JP2008052268A - Method for manufacturing display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device that can be manufactured while improving use efficiency of materials and simplifying manufacture steps, and to provide techniques of manufacturing the device. <P>SOLUTION: A light absorbing layer is formed; an insulating layer is formed on the light absorbing layer; the light absorbing layer and the insulating layer are selectively irradiated with laser light to remove the irradiated region of the insulating layer to form an opening in the insulating layer; and a conductive film is formed in the opening so as to be in contact with the light absorbing layer. By forming the conductive layer in the opening so as to be in contact with the exposed light absorbing layer, the light absorbing layer and the conductive film can be electrically connected via the insulating layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a method for manufacturing a display device having a thin film stacked structure. Specifically, the present invention relates to a step of forming an opening in a thin film in a step of manufacturing a display device.

A thin film transistor (hereinafter also referred to as “TFT”) and an electronic circuit using the thin film transistor are obtained by laminating various thin films such as a semiconductor, an insulating film, and a conductive film on a substrate and appropriately forming a predetermined pattern by a photolithography technique. It is manufactured. Photolithographic technology is a technology that uses a light to transfer a circuit pattern or other pattern formed on a transparent flat plate called a photomask onto a target substrate. It is widely used in the manufacturing process.

In the manufacturing process using the conventional photolithography technology, a multi-step process such as exposure, development, baking, and peeling is required only for handling a mask pattern formed using a photosensitive organic resin material called a photoresist. Become. Therefore, the manufacturing cost inevitably increases as the number of photolithography processes increases. In order to improve such problems, attempts have been made to manufacture TFTs by reducing the photolithography process (see, for example, Patent Document 1). In Patent Document 1, after a resist mask formed by a photolithography process is used once, it is subjected to volume expansion by swelling and used again as a resist mask having a different shape.
JP 2000-133636 A

The present invention reduces the number of photolithography processes in the manufacturing process of a TFT, an electronic circuit using the TFT, and a display device formed by the TFT, simplifies the manufacturing process, and a large-area substrate whose one side exceeds 1 meter. Another object of the present invention is to provide a technique that can be manufactured at a low cost and with a high yield.

In the present invention, when thin films (conductive layers and semiconductor layers) stacked via an insulating layer are electrically connected to each other, an opening (a so-called contact hole) is formed in the insulating layer. In this case, the mask layer is not formed over the insulating layer, and the opening is selectively formed by laser light irradiation. After forming a light absorption layer having a function of absorbing irradiated light and laminating an insulating layer on the light absorption layer, the insulating layer side is selectively formed in a region where an opening is formed in the lamination of the light absorption layer and the insulating layer. The laser beam is irradiated from Laser light passes through the insulating layer, but is absorbed by the light absorption layer. The light absorption layer is heated by the energy of the absorbed laser light, and destroys the insulating layer laminated thereon. Accordingly, an opening is formed in the insulating layer, and the light absorption layer under the insulating layer is exposed on the bottom surface of the opening.

When the light absorption layer is formed using a conductive material such as a conductive layer using a conductive material or a semiconductor layer using a semiconductor material, a conductive film is formed in the opening so as to be in contact with the exposed light absorption layer. Thus, the light absorption layer and the conductive film can be electrically connected through the insulating layer. In other words, in the present invention, openings are formed in the insulating layer formed on the light absorption layer functioning as a conductive layer and a semiconductor layer by irradiating the light absorption layer with laser light, and the light absorption layer is formed by laser ablation. An opening is formed in the insulating layer on the laser irradiation region.

Since openings can be selectively formed by laser light, a mask layer is not required and processes and materials can be reduced. In addition, since the laser beam can be focused on a very small spot, the insulating layer to be processed can be processed into a predetermined shape with high accuracy, and it can be heated instantaneously in a short time. There is an advantage of not having to.

In addition, a conductive layer, a semiconductor layer, or the like used when the thin film is processed into a desired pattern is selectively formed to have a desired shape without using a photolithography process. A light-absorbing film such as a conductive film or a semiconductor film is formed over the translucent transfer substrate, and laser light is selectively irradiated from the transfer substrate side, so that the light-absorbing film corresponding to the laser light irradiation region is formed. It transfers to a transfer board | substrate and forms the conductive layer and semiconductor layer which are light absorption layers with a desired shape (pattern). In this specification, a conductive film or a semiconductor film which is a light absorption film is formed in the first step, a substrate to be irradiated with laser light is a transfer substrate, and finally a conductive layer or a semiconductor layer which is a light absorption layer selectively. The substrate on which is formed is also referred to as a transferred substrate. Since a desired shape can be selectively formed without using a photolithography process, process simplification, cost reduction, and the like can be achieved.

One method for manufacturing a display device of the present invention is to form a light absorption layer, form an insulating layer over the light absorption layer, selectively irradiate the light absorption layer and the insulating layer with laser light, and irradiate the insulating layer. The region is removed, an opening is formed in the insulating layer, and a conductive film is formed in the opening so as to be in contact with the light absorption layer.

According to one method for manufacturing a display device of the present invention, a conductive layer is formed, a light absorption layer is formed over the conductive layer, an insulating layer is formed over the light absorption layer, and the light absorption layer and the insulating layer are selectively formed. Irradiation with a laser beam is performed, an irradiation region of the insulating layer is removed, an opening is formed in the insulating layer, and a conductive film is formed in contact with the light absorption layer in the opening.

The light absorption layer formed above only needs to absorb irradiated laser light. When a conductive material is used, the light absorption layer can be a conductive layer. When a semiconductor material is used, the light absorption layer can be a semiconductor layer. It can be used for any conductive layer or semiconductor layer constituting the display device. For example, the conductive layer can be used for a wiring layer, a gate electrode layer, a source electrode layer, a drain electrode layer, a pixel electrode layer, and the like.

In the above structure, a conductive material can be used for the light absorption layer, and for example, one or more of chromium, tantalum, silver, molybdenum, nickel, titanium, cobalt, copper, or aluminum can be used. A semiconductor material can also be used for the light absorption layer, for example, silicon (silicon), germanium, silicon germanium, gallium arsenide, molybdenum oxide, tin oxide, bismuth oxide, vanadium oxide, nickel oxide, zinc oxide, gallium arsenide. Inorganic semiconductor materials such as gallium nitride, indium oxide, indium phosphide, indium nitride, cadmium sulfide, cadmium telluride, and strontium titanate can be used. Further, hydrogen or an inert gas (such as helium (He), argon (Ar), krypton (Kr), neon (Ne), or xenon (Xe)) may be added to the light absorption layer. The insulating layer for forming the opening can be formed using a material that transmits laser light, such as a light-transmitting inorganic insulating material or an organic resin.

The present invention can also be used for a display device that is a device having a display function. The display device using the present invention includes an organic substance, an inorganic substance, and an organic substance that emits light called electroluminescence (hereinafter also referred to as “EL”). Alternatively, there are a light-emitting display device in which a light-emitting element in which a layer containing a mixture of an organic substance and an inorganic substance is interposed between electrodes and a TFT are connected, and a liquid crystal display device in which a liquid crystal element having a liquid crystal material is used as a display element. In the present invention, a display device refers to a device having a display element (such as a liquid crystal element or a light emitting element). Note that a display panel body in which a plurality of pixels including a display element such as a liquid crystal element or an EL element and a peripheral driver circuit for driving these pixels are formed over a substrate may be used. Furthermore, a device to which a flexible printed circuit (FPC) or a printed wiring board (PWB) is attached (such as an IC, a resistor, a capacitor, an inductor, or a transistor) may also be included. Furthermore, an optical sheet such as a polarizing plate or a retardation plate may be included. Furthermore, a backlight (which may include a light guide plate, a prism sheet, a diffusion sheet, a reflection sheet, or a light source (such as an LED or a cold cathode tube)) may be included.

Note that the display element and the display device can have various forms or have various elements. For example, EL elements (organic EL elements, inorganic EL elements or EL elements including organic and inorganic substances), electron-emitting elements, liquid crystal elements, electronic ink, grating light valves (GLV), plasma displays (PDP), digital micromirror devices ( DMD), piezoelectric ceramic displays, carbon nanotubes, and the like, which can be applied to display media whose contrast is changed by an electromagnetic action. Note that a display device using an EL element is an EL display, and a display device using an electron-emitting device is a liquid crystal display such as a field emission display (FED) or a SED type flat display (SED: Surface-conduction Electron-Emitter Display). A display device using the element includes a liquid crystal display, a transmissive liquid crystal display, a transflective liquid crystal display, a reflective liquid crystal display, and a display device using electronic ink includes electronic paper.

Further, by using the present invention, a device having a circuit including a semiconductor element (a transistor, a memory element, a diode, or the like) or a semiconductor device such as a chip having a processor circuit can be manufactured. Note that in the present invention, a semiconductor device refers to a device that can function by utilizing semiconductor characteristics.

According to the present invention, a component such as a wiring constituting a display device or the like, and a contact hole for electrically connecting them through an insulating layer can be formed while reducing a complicated photolithography process. Therefore, since a display device can be manufactured through a simplified process, material loss is small and cost reduction can be achieved. A high-performance and highly reliable display device can be manufactured with high yield.

Embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below. Note that in structures of the present invention described below, the same portions or portions having similar functions are denoted by the same reference numerals in different drawings, and description thereof is not repeated.

(Embodiment 1)
In this embodiment mode, a method for forming a contact hole, which has high reliability and is manufactured at a low cost with a simplified process, will be described with reference to FIGS.

In the case of electrically connecting thin films (conductive layer and semiconductor layer) stacked via an insulating layer, an opening (a so-called contact hole) is formed in the insulating layer. In this case, the mask layer is not formed over the insulating layer, and the opening is selectively formed by laser light irradiation. After forming a light absorption layer having a function of absorbing irradiated light and laminating an insulating layer on the light absorption layer, the insulating layer side is selectively formed in a region where an opening is formed in the lamination of the light absorption layer and the insulating layer. The laser beam is irradiated from Laser light passes through the insulating layer, but is absorbed by the light absorption layer. The light absorption layer is heated by the energy of the absorbed laser light, and destroys the insulating layer laminated thereon. Accordingly, an opening is formed in the insulating layer, and the light absorption layer under the insulating layer is exposed on the bottom surface of the opening.

When the light absorption layer is formed using a conductive material such as a conductive layer using a conductive material or a semiconductor layer using a semiconductor material, a conductive film is formed in the opening so as to be in contact with the exposed light absorption layer. Thus, the light absorption layer and the conductive film can be electrically connected through the insulating layer. In other words, in the present invention, openings are formed in the insulating layer formed on the light absorption layer functioning as a conductive layer and a semiconductor layer by irradiating the light absorption layer with laser light, and the light absorption layer is formed by laser ablation. An opening is formed in the insulating layer on the laser irradiation region.

Since openings can be selectively formed by laser light, a mask layer is not required and processes and materials can be reduced. In addition, since the laser beam can be focused on a very small spot, the insulating layer to be processed can be processed into a predetermined shape with high accuracy, and it can be heated instantaneously in a short time. There is an advantage of not having to.

This will be specifically described with reference to FIG. In this embodiment mode, as illustrated in FIG. 1, a light absorption layer 721 and an insulating layer 722 are formed over a substrate 720. In this embodiment mode, a conductive material is used for the light absorption layer 721, and the light absorption layer 721 can function as a conductive layer. In this embodiment mode, chromium is used for the light absorption layer 721.

As shown in FIG. 1B, the light absorption layer 721 is selectively irradiated with laser light 723 from the insulating layer 722 side, and the insulating layer 722 on the irradiation region of the light absorption layer 721 is removed by the irradiated energy. , An opening 725 can be formed. The insulating layer 722 is separated into an insulating layer 727a and an insulating layer 727b (see FIG. 1C). A conductive film 726 can be formed in the opening 725 in which the light absorption layer 721 is exposed, so that the light absorption layer 721 and the conductive film 726 can be electrically connected to each other (see FIG. 1D).

A laser beam drawing apparatus that draws laser light (also referred to as a laser beam) in a processing region will be described with reference to FIG. In this embodiment mode, a laser beam direct writing apparatus is used for processing by directly irradiating a processing region with a laser beam. As shown in FIG. 30, a laser beam direct writing apparatus 1001 includes a personal computer (hereinafter referred to as a PC) 1002 that executes various controls when irradiating a laser beam, a laser oscillator 1003 that outputs a laser beam, and a laser. A power source 1004 of the oscillator 1003, an optical system (ND filter) 1005 for attenuating the laser beam, an acousto-optic modulator (AOM) 1006 for modulating the intensity of the laser beam, and an enlargement or reduction of the cross section of the laser beam An optical system 1007 composed of a lens for changing the optical path, a mirror for changing the optical path, etc., a substrate moving mechanism 1009 having an X stage and a Y stage, and D / D for digital-to-analog conversion of control data output from the PC A converter 1010 and the sound according to the analog voltage output from the D / A converter It includes a driver 1011 for controlling the academic modulator 1006, a driver 1012 for outputting a driving signal for driving the substrate moving mechanism 1009.

As the laser oscillator 1003, a laser oscillator that can oscillate ultraviolet light, visible light, or infrared light can be used. Examples of laser oscillators include excimer laser oscillators such as KrF, ArF, XeCl, and Xe, gas laser oscillators such as He, He—Cd, Ar, He—Ne, and HF, YAG, GdVO ₄ , YVO ₄ , YLF, and YAlO _3. A solid-state laser oscillator using a crystal doped with Cr, Nd, Er, Ho, Ce, Co, Ti, or Tm, and a semiconductor laser oscillator such as GaN, GaAs, GaAlAs, or InGaAsP can be used. In the solid-state laser oscillator, it is preferable to apply the fundamental wave and the first to fifth harmonics of the fundamental wave. In order to adjust the shape of the laser light emitted from the laser oscillator and the path of the laser light, an optical system including a reflector such as a shutter, a mirror or a half mirror, a cylindrical lens, or a convex lens may be installed.

Further, the laser crystallization may be performed using a frequency band significantly higher than a frequency band of several tens to several hundreds Hz that is usually used with an oscillation frequency of pulsed laser light of 0.5 MHz or more. A pulse laser with a pulse width in the picosecond range or a femtosecond ( ^10-15 seconds) range may be used.

Further, the laser beam may be irradiated in an inert gas atmosphere such as a rare gas or nitrogen, or the laser beam may be irradiated under reduced pressure.

Next, a film modification process using a laser beam direct writing apparatus will be described. When the substrate 1008 is mounted on the substrate moving mechanism 1009, the PC 1002 detects the position of the marker attached to the substrate by a camera (not shown). Next, the PC 1002 generates movement data for moving the substrate movement mechanism 1009 based on the detected marker position data and drawing pattern data input in advance. Thereafter, the PC 1002 controls the output light amount of the acousto-optic modulator 1006 via the driver 1011, whereby the laser beam output from the laser oscillator 1003 is attenuated by the optical system 1005, and then the acousto-optic modulator 1006. The light amount is controlled so as to be a predetermined light amount. On the other hand, the laser beam output from the acousto-optic modulator 1006 is changed in optical path and beam shape by the optical system 1007 and condensed by the lens, and then the base film formed on the substrate is irradiated with the beam, The membrane is modified. At this time, according to the movement data generated by the PC 1002, the movement of the substrate moving mechanism 1009 is controlled in the X direction and the Y direction. As a result, a laser beam is irradiated to a predetermined place, and film modification processing is performed.

The shorter the laser beam, the shorter the beam diameter can be focused. Therefore, it is preferable to irradiate the laser beam with a short wavelength in order to process a region with a fine width.

In addition, the spot shape on the film surface of the laser beam is processed by an optical system so as to be a dot, circle, ellipse, rectangle, or line (strictly, an elongated rectangle).

The apparatus shown in FIG. 30 shows an example in which exposure is performed by irradiating a laser beam from the front side of the substrate. However, the optical system and the substrate moving mechanism are appropriately changed, and the laser beam is irradiated from the back side of the substrate. Alternatively, a laser beam drawing apparatus that performs exposure may be used.

Note that here, the laser beam is selectively irradiated by moving the substrate; however, the present invention is not limited to this, and the laser beam can be irradiated by scanning the laser beam in the X and Y axis directions. In this case, it is preferable to use a polygon mirror or a galvanometer mirror for the optical system 1007.

The light absorption layer 721 can be formed by a vapor deposition method, a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method such as a plasma CVD method (Chemical Vapor Deposition), or the like. In addition, a method in which the composition can be transferred or drawn in a desired pattern, for example, various printing methods (screen (stencil) printing, offset (flat plate) printing, letterpress printing, gravure (intaglio printing), etc.) ), A dispenser method, a selective coating method, and the like can also be used.

The light absorption layer 721 can be formed using one or more of chromium, molybdenum, nickel, titanium, cobalt, copper, tungsten, or aluminum. A semiconductor material can also be used for the light absorption layer, for example, silicon (silicon), germanium, silicon germanium, gallium arsenide, molybdenum oxide, tin oxide, bismuth oxide, vanadium oxide, nickel oxide, zinc oxide, gallium arsenide. Inorganic semiconductor materials such as gallium nitride, indium oxide, indium phosphide, indium nitride, cadmium sulfide, cadmium telluride, and strontium titanate can be used. Further, hydrogen or an inert gas (such as helium (He), argon (Ar), krypton (Kr), neon (Ne), or xenon (Xe)) may be added to the light absorption layer. The insulating layer for forming the opening can be formed using a material that transmits laser light, such as a light-transmitting inorganic insulating material or an organic resin.

In addition, the shape of the opening functioning as the contact hole may not be perpendicular to the bottom surface, and the opening may have a tapered side. For example, the shape of the opening may be a mortar shape, and the side surface of the opening may be tapered with respect to the bottom surface.

In this manner, the light absorption layer below the insulating layer and the conductive film on the insulating layer are electrically connected in the opening provided in the insulating layer. The size and shape of the opening formed in the insulating layer can be controlled by the irradiation conditions (energy intensity, irradiation time, etc.) of the laser beam and the properties of the insulating layer and conductive layer (thermal conductivity, melting point, boiling point, etc.). it can.

The size of the opening with respect to the irradiation region determined by the diameter of the laser beam depends on the energy of the laser beam. If the laser beam energy is sufficiently large, the energy is transmitted to the periphery of the irradiation region and the laser is transmitted to the insulating layer. An opening larger than the light irradiation region is formed. Conversely, when the energy of the laser beam is small, an opening having almost the same size as the irradiated region is formed in the insulating layer.

As described above, by controlling the energy of the laser light, the size of the opening formed in the insulating layer can be appropriately controlled.

After the opening is formed by laser light irradiation, the conductive material and insulating material remaining in the vicinity of the opening with a liquid are washed to remove the residue. Also good. In this case, an unreacted substance such as water may be used for cleaning, or a chemical solution such as an etchant that reacts (dissolves) with the insulating layer may be used. When an etchant is used, the opening is over-etched, dust and the like are removed, and the surface is flattened. The opening can also be widened.

Since openings can be selectively formed by laser light, a mask layer is not required and processes and materials can be reduced. In addition, since the laser beam can be focused on a very small spot, the conductive layer and insulating layer to be processed can be processed into a predetermined shape with high accuracy and can be heated instantaneously in a short time. There is an advantage that almost no heating is required.

Thus, an opening (contact hole) for electrically connecting the conductive layer and the conductive layer can be formed in the insulating layer by laser light irradiation without performing a complicated photolithography process and formation of a mask layer.

Therefore, when a display device is manufactured using the present invention, the process can be simplified, so that material loss is small and cost reduction can be achieved. Thus, a display device can be manufactured with high yield.

(Embodiment 2)
In this embodiment, a method for forming a contact hole, which is highly reliable and is intended to be manufactured at a low cost through a simplified process, will be described with reference to FIGS.

In this embodiment, an example in which the conductive film is electrically connected to the stack of the light absorption layer and the conductive layer through the insulating layer in Embodiment 1 is described.

This will be specifically described with reference to FIG. In this embodiment mode, as illustrated in FIG. 2, a conductive layer 709, a light absorption layer 701, and an insulating layer 702 are formed over a substrate 700. In this embodiment, a material having conductivity is used for the light absorption layer 701, and the light absorption layer 701 can function as a conductive layer. Alternatively, the conductive layer 709 may be formed using a material that absorbs laser light to serve as a light absorption layer.

The conductive layer 709 and the light absorption layer 701 have a stacked structure. In this embodiment, a low melting point metal (chromium in this embodiment) that is relatively easily evaporated is used for the light absorption layer 701, and the conductive layer 709 is used. For this, a refractory metal (tungsten in this embodiment) that is harder to evaporate than the light absorption layer 701 is used.

As shown in FIG. 2B, the light absorption layer 701 is selectively irradiated with laser light 703 from the insulating layer 702 side, and the insulating layer 702 on the irradiation region of the light absorption layer 701 is removed by the irradiated energy. The opening 705 can be formed. The insulating layer 702 is separated into an insulating layer 707a and an insulating layer 707b (see FIG. 2C). A conductive film 706 can be formed in the opening 705 from which the light absorption layer 701 is exposed, so that the conductive layer 709, the light absorption layer 701, and the conductive film 706 can be electrically connected (see FIG. 2D).

As described above, the light absorption layer may be stacked with a conductive layer (or a semiconductor layer), and the light absorption layer itself and the conductive layer itself may be stacked.

After the opening is formed by laser light irradiation, the conductive material and insulating material remaining in the vicinity of the opening with a liquid are washed to remove the residue. Also good. In this case, an unreacted substance such as water may be used for cleaning, or a chemical solution such as an etchant that reacts (dissolves) with the insulating layer may be used. When an etchant is used, the opening is over-etched, dust and the like are removed, and the surface is flattened. The opening can also be widened.

In this manner, the light absorption layer below the insulating layer and the conductive film on the insulating layer are electrically connected in the opening provided in the insulating layer. In this embodiment mode, a light-absorbing layer made of a highly sublimable metal is formed over a conductive layer, and energy is applied to the light-absorbing layer with a laser beam, whereby an insulating layer formed over the light-absorbing layer and the conductive layer is formed. Form an opening. The size and shape of the opening formed in the insulating layer can be controlled by the irradiation conditions (energy intensity, irradiation time, etc.) of the laser beam and the properties of the insulating layer and conductive layer (thermal conductivity, melting point, boiling point, etc.). it can. An example of the size of the laser beam and the size of the opening to be formed is shown in FIG.

A conductive layer 309 (309a, 309b, 309c) and a light absorption layer 301 are stacked over the substrate 300, and an insulating layer 302 is formed to cover the conductive layer 309 (309a, 309b, 309c) and the light absorption layer 301. Is formed. 4, a conductive layer 309 (309a, 309b, 309c) has a stacked structure including a plurality of thin films. For example, the conductive layer 309a is titanium, the conductive layer 309b is aluminum, the conductive layer 309c is titanium, and the light absorption layer 301 is Chrome can be used. In addition, tungsten, molybdenum, or the like can be used for the conductive layer 309 (309a, 309b, and 309c). Needless to say, the light absorption layer 301 can also have a stacked structure, and a stacked layer of copper and chromium can be used.

The insulating layer 302 and the light absorption layer 301 are selectively irradiated with a laser beam 303 having a laser diameter L1. When the energy of the laser beam 303 is large, as shown in FIG. 4C, the energy given to the light absorption layer 301 is also large, and heat is conducted to the irradiation region and its periphery in the light absorption layer 301. Therefore, an opening 305 having a diameter L2 larger than the diameter L1 of the laser beam 303 is formed in the insulating layer 302 formed on the light absorption layer 301. As described above, the insulating layer 302 is divided into the insulating layers 307a and 307b, and the opening 305 is formed. A conductive film 306 is formed in the opening 305 where the light absorption layer 301 is exposed, and the conductive layer 309 (309a, 309b, and 309c) and the light absorption layer 301 and the conductive film 306 are electrically connected to each other (FIG. 4D). reference.).

The size of the opening with respect to the irradiation region determined by the diameter of the laser beam depends on the energy of the laser beam. If the laser beam energy is sufficiently large, the energy is transmitted to the periphery of the irradiation region and the laser is transmitted to the insulating layer. An opening larger than the light irradiation region is formed. Conversely, when the energy of the laser beam is small, an opening having almost the same size as the irradiated region is formed in the insulating layer.

As described above, by controlling the energy of the laser light, the size of the opening formed in the insulating layer can be appropriately controlled.

Since openings can be selectively formed by laser light, a mask layer is not required and processes and materials can be reduced. In addition, since the laser beam can be focused on a very small spot, the conductive layer and insulating layer to be processed can be processed into a predetermined shape with high accuracy and can be heated instantaneously in a short time. There is an advantage that almost no heating is required.

Thus, an opening (contact hole) for electrically connecting the conductive layer and the conductive layer can be formed in the insulating layer by laser light irradiation without performing a complicated photolithography process and formation of a mask layer.

Therefore, when a display device is manufactured using the present invention, the process can be simplified, so that material loss is small and cost reduction can be achieved. Thus, a display device can be manufactured with high yield.

(Embodiment 3)
In this embodiment, a method for manufacturing a display device, which has high reliability and is manufactured at a low cost with a simplified process, will be described with reference to FIGS.

In this embodiment mode, a structure (also referred to as a pattern) such as a conductive layer and a semiconductor layer is selectively formed to have a desired shape without using a photolithography process when the thin film is processed into a desired pattern. . In the present invention, a component (also referred to as a pattern) refers to a conductive layer such as a wiring layer, a gate electrode layer, a source electrode layer, and a drain electrode layer, a semiconductor layer, a mask layer, an insulating layer, etc. that constitute a thin film transistor or a display device. Including all components formed with a predetermined shape.

In this embodiment mode, a light-absorbing film such as a conductive film or a semiconductor film is formed over a light-transmitting transfer substrate, and laser light is selectively irradiated from the transfer substrate side, thereby corresponding to the laser light irradiation region. The light absorption film is transferred to the transfer substrate, and a conductive layer and a semiconductor layer which are light absorption layers are formed in a desired shape (pattern). In this specification, a conductive film or a semiconductor film which is a light absorption film is formed in the first step, a substrate to be irradiated with laser light is a transfer substrate, and finally a conductive layer or a semiconductor layer which is a light absorption layer selectively. The substrate on which is formed is also referred to as a transferred substrate. Since a desired shape can be selectively formed without using a photolithography process, process simplification, cost reduction, and the like can be achieved.

A method for forming a thin film described in this embodiment will be described in detail with reference to FIGS. In FIG. 3, a light absorption film 2202 is formed on a first substrate 2201 which is a transfer substrate, and the first substrate 2201 and a second substrate 2200 which is a transfer substrate so that the light absorption film 2202 is inside. Are installed facing each other.

From the substrate 2201 side, the light absorption film 2202 is selectively irradiated with the laser light 2203 through the substrate 2201. The light absorption film 2202 in the region irradiated with the laser light 2203 absorbs the laser light 2203 and is transferred as a light absorption layer 2205 to the second substrate 2200 side by energy such as heat. On the other hand, the region not irradiated with the laser light 2203 remains on the first substrate 2201 side as the light absorption films 2204a and 2204b. In this manner, a structure (also referred to as a pattern) such as a conductive layer and a semiconductor layer is selectively formed into a desired shape without using a photolithography process when the thin film that is the light absorption layer 2206 is processed into a desired pattern. Form to have.

A laser beam similar to the laser beam described in Embodiment Mode 1 can be used for irradiation, and the laser beam direct drawing apparatus illustrated in FIG. 30 may be used. Therefore, detailed description is omitted here.

After the transfer with the laser beam, the light absorption layer may be subjected to heat treatment or may be irradiated with the laser beam.

A light-absorbing film 2202 that is a transposed material is formed using a material that absorbs irradiated light, and the first substrate 2201 is a light-transmitting substrate that transmits the irradiated light. When the present invention is used, the substrate can be freely transferred to various substrates, so that the range of substrate material selectivity is widened. In addition, an inexpensive material can be selected as the substrate, so that not only a wide function can be provided depending on the application, but also a display device can be manufactured at low cost.

The thin film formation method of this embodiment is used for forming a conductive layer such as a wiring layer, a gate electrode layer, a source electrode layer, and a drain electrode layer, a semiconductor layer, a mask layer, an insulating layer, and the like which constitute a thin film transistor or a display device. A film using a desired material can be formed as the light absorption film, and light absorbed by the film can be selected and irradiated.

For example, a conductive material can be used for the light absorption film, and for example, one or more of chromium, tantalum, silver, molybdenum, nickel, titanium, cobalt, copper, or aluminum can be used. A semiconductor material can also be used as the light absorption film, for example, silicon (silicon), germanium, silicon germanium, gallium arsenide, molybdenum oxide, tin oxide, bismuth oxide, vanadium oxide, nickel oxide, zinc oxide, gallium arsenide. Inorganic semiconductor materials such as gallium nitride, indium oxide, indium phosphide, indium nitride, cadmium sulfide, cadmium telluride, and strontium titanate can be used. Further, hydrogen or an inert gas (such as helium (He), argon (Ar), krypton (Kr), neon (Ne), or xenon (Xe)) may be added to the light absorption film.

According to the present invention, a component such as a wiring constituting the display device can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

(Embodiment 4)
FIG. 25A is a top view illustrating a structure of a display panel according to the present invention. A pixel portion 2701 in which pixels 2702 are arranged in a matrix over a substrate 2700 having an insulating surface, a scanning line side input terminal 2703, a signal A line side input terminal 2704 is formed. The number of pixels may be provided in accordance with various standards. For full color display using XGA and RGB, 1024 × 768 × 3 (RGB), and for full color display using UXGA and RGB, 1600 × 1200. If it corresponds to x3 (RGB) and full spec high vision and is full color display using RGB, it may be 1920 x 1080 x 3 (RGB).

The pixels 2702 are arranged in a matrix by a scan line extending from the scan line side input terminal 2703 and a signal line extending from the signal line side input terminal 2704 intersecting. Each of the pixels 2702 includes a switching element and a pixel electrode connected to the switching element. A typical example of the switching element is a TFT. By connecting the gate electrode side of the TFT to a scanning line and the source or drain side to a signal line, each pixel can be controlled independently by a signal input from the outside. Yes.

FIG. 25A shows the structure of a display panel in which signals input to the scan lines and signal lines are controlled by an external driver circuit. As shown in FIG. 26A, COG (Chip on The driver IC 2751 may be mounted on the substrate 2700 by a glass method. As another mounting mode, a TAB (Tape Automated Bonding) method as shown in FIG. 26B may be used. The driver IC may be formed on a single crystal semiconductor substrate or may be a circuit in which a TFT is formed on a glass substrate. In FIG. 26, the driver IC 2751 is connected to the FPC 2750.

In the case where a TFT provided for a pixel is formed using a polycrystalline (microcrystalline) semiconductor with high crystallinity, a scan line driver circuit 3702 may be formed over the substrate 3700 as illustrated in FIG. it can. In FIG. 25B, reference numeral 3701 denotes a pixel portion, and the signal line side driver circuit is controlled by an external driver circuit as in FIG. In the case where a TFT provided for a pixel is formed using a high mobility polycrystalline (microcrystalline) semiconductor, single crystal semiconductor, or the like like the TFT formed in the present invention, FIG. 4702 and the signal line side driver circuit 4704 can be formed over the substrate 4700 integrally.

Embodiment modes of the present invention will be described with reference to FIGS. More specifically, a method for manufacturing a display device having an inverted staggered thin film transistor to which the present invention is applied will be described. 8A to 13A are top views of the display device pixel portion, and FIGS. 8B to 13B are cross-sectional views taken along line A-C in FIGS. 8A to 13A. C) is a sectional view taken along line BD. 14A and 14B are also cross-sectional views of the display device.

As the substrate 100, a glass substrate made of barium borosilicate glass, alumino borosilicate glass, or the like, a quartz substrate, a metal substrate, or a plastic substrate having heat resistance that can withstand the processing temperature in this manufacturing process is used. Further, polishing may be performed by a CMP method or the like so that the surface of the substrate 100 is planarized. Note that an insulating layer may be formed over the substrate 100. The insulating layer is formed as a single layer or a stacked layer using an oxide material or a nitride material containing silicon by various methods such as a CVD method, a plasma CVD method, a sputtering method, and a spin coating method. This insulating layer may not be formed, but has an effect of blocking contaminants from the substrate 100.

Gate electrode layers 103 (103a and 103b) and 104 (104a and 104b) are formed over the substrate 100. The gate electrode layers 103 (103a, 103b), 104 (104a, 104b) are formed of an element selected from Ag, Au, Ni, Pt, Pd, Ir, Rh, Ta, W, Ti, Mo, Al, Cu, or What is necessary is just to form with the alloy material or compound material which has the said element as a main component. Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus, or an AgPdCu alloy may be used. Alternatively, a single-layer structure or a multi-layer structure may be used, for example, a two-layer structure of a tungsten nitride film and a molybdenum (Mo) film, a tungsten film with a thickness of 50 nm, or an alloy of aluminum and silicon with a thickness of 500 nm. A three-layer structure in which an (Al—Si) film and a titanium nitride film with a thickness of 30 nm are sequentially stacked may be employed. In the case of a three-layer structure, tungsten nitride may be used instead of tungsten of the first conductive film, or aluminum instead of the aluminum and silicon alloy (Al-Si) film of the second conductive film. A titanium alloy film (Al—Ti) may be used, or a titanium film may be used instead of the titanium nitride film of the third conductive film.

The gate electrode layers 103a, 103b, 104a, and 104b are formed using a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method (Chemical Vapor Deposition) such as a plasma CVD method, or the like. And can be formed by processing using a mask layer. In addition, a method in which the composition can be transferred or drawn in a desired pattern, for example, various printing methods (screen (stencil) printing, offset (flat plate) printing, letterpress printing, gravure (intaglio printing), etc.) ), A droplet discharge method, a dispenser method, a selective coating method, and the like can also be used.

The conductive film may be processed by dry etching or wet etching. Using an ICP (Inductively Coupled Plasma) etching method, the etching conditions (the amount of power applied to the coil-type electrode, the amount of power applied to the substrate-side electrode, the electrode temperature on the substrate side, etc.) are appropriately set. By adjusting, the electrode layer can be etched into a tapered shape. As an etching _gas, using Cl _2, BCl 3, SiCl ₄ or a chlorine-based gas typified by CCl _4, fluorine-based gas or _{O 2} and typified by CF 4, SF ₆ or NF ₃ as appropriate be able to.

In this embodiment mode, the gate electrode layer is formed by forming a conductive film which is a light absorption film over the transfer substrate and then selectively processing the transfer substrate into a desired shape with a laser beam. A light absorption film is formed over the substrate 101 by a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method such as a plasma CVD method (Chemical Vapor Deposition), or the like.

The light absorption film is formed over the substrate 101 which is a transfer substrate, and the substrate 101 and the substrate 100 are placed facing each other so that the substrate 100 which is a transfer substrate and the light absorption film are inside.

From the substrate 101 side, the light absorption film is selectively irradiated with laser beams 112a, 112b, 112c, and 112d through the substrate 101. The light absorption film in the region irradiated with the laser beams 112a, 112b, and 112c absorbs the laser beams 112a, 112b, 112c, and 112d, and the gate electrode layer 103 (103a and 103b) is formed on the substrate 100 side by energy such as heat. , 104 (104a, 104b). On the other hand, the regions not irradiated with the laser beams 112a, 112b, 112c, and 112d remain on the substrate 101 side as the light absorption films 102a, 102b, 102c, and 102d. In this manner, the light absorption film is selectively transferred, and the gate electrode layers 103 (103a and 103b) and 104 (104a and 104b) are selectively formed to have a desired shape without using a photolithography process. (See FIGS. 8A to 8C.)

After the transfer with the laser beam, the light absorption layer may be subjected to heat treatment or may be irradiated with the laser beam.

A light-absorbing film that is a transposed material is formed using a light-absorbing material, and the substrate 101 is a light-transmitting substrate that transmits the irradiated light. When the present invention is used, the substrate can be freely transferred to various substrates, so that the range of substrate material selectivity is widened. In addition, an inexpensive material can be selected as the substrate, so that not only a wide function can be provided depending on the application, but also a display device can be manufactured at low cost.

Next, the gate insulating layer 105 is formed over the gate electrode layers 103 (103a and 103b) and 104 (104a and 104b). The gate insulating layer 105 may be formed of a material such as a silicon oxide material or a nitride material, and may be a stacked layer or a single layer. In this embodiment, a two-layer stack of a silicon nitride film and a silicon oxide film is used. Alternatively, a single layer of silicon oxynitride film or a stack of three or more layers may be used. A silicon nitride film having a dense film quality is preferably used. In addition, when silver or copper is used for a conductive layer formed by a droplet discharge method, if a silicon nitride film or a NiB film is formed thereon as a barrier film, diffusion of impurities can be prevented and the surface can be planarized. is there. Note that in order to form a dense insulating film with low gate leakage current at a low deposition temperature, a rare gas element such as argon is preferably contained in a reaction gas and mixed into the formed insulating film.

Next, an opening 107 is formed in the gate insulating layer 105. A mask layer made of an insulator such as resist or polyimide is formed by a droplet discharge method, and an opening 107 is formed in a part of the gate insulating layer 105 by etching using the mask layer, and the lower layer side A part of the gate electrode layer 104 disposed on the substrate can be exposed. The etching process may be either plasma etching (dry etching) or wet etching, but plasma etching is suitable for processing a large area substrate. As an etching gas, a fluorine-based or chlorine-based gas such as CF ₄ , NF ₃ , Cl ₂ , or BCl ₃ may be used, and an inert gas such as He or Ar may be appropriately added. Further, if an atmospheric pressure discharge etching process is applied, a local electric discharge process is also possible, and it is not necessary to form a mask layer on the entire surface of the substrate.

In this embodiment mode, the opening 107 is formed using laser light as described in Embodiment Mode 1 (see FIGS. 9A to 9C). The gate electrode layer 104 is selectively irradiated with laser light 106 from the gate insulating layer 105 side, and the gate insulating layer 105 on the irradiation region of the gate electrode layer 104 is removed by the irradiated energy, so that an opening 107 can be formed. it can. A conductive film for forming a source electrode layer or a drain electrode layer is formed in the opening 107 from which the gate electrode layer 104 is exposed, and the gate electrode layer 104 and the source electrode layer or the drain electrode layer can be electrically connected. The opening 107 may be formed after the semiconductor layer is formed.

Next, a semiconductor layer is formed. A semiconductor layer having one conductivity type may be formed as necessary. In addition, an n-type semiconductor layer is formed, an n-channel TFT NMOS structure, a p-channel TFT PMOS structure having a p-type semiconductor layer, and an n-channel TFT and p-channel TFT CMOS structure. Can be produced. Further, in order to impart conductivity, an n-channel TFT or a p-channel TFT can be formed by adding an element imparting conductivity by doping and forming an impurity region in the semiconductor layer. Instead of forming an n-type semiconductor layer, conductivity may be imparted to the semiconductor layer by performing plasma treatment with a PH ₃ gas.

As a material for forming the semiconductor layer, an amorphous semiconductor (hereinafter also referred to as “AS”) manufactured by a vapor deposition method or a sputtering method using a semiconductor material gas typified by silane or germane is used. A polycrystalline semiconductor crystallized using energy or thermal energy, a semi-amorphous (also referred to as microcrystal or microcrystal, hereinafter, also referred to as “SAS”) semiconductor, or the like can be used. The semiconductor layer can be formed by various means (such as sputtering, LPCVD, or plasma CVD).

SAS is a semiconductor having an intermediate structure between amorphous and crystalline structures (including single crystal and polycrystal) and having a third state that is stable in terms of free energy and has a short-range order and a lattice. It includes a crystalline region with strain. A crystal region of 0.5 to 20 nm can be observed in at least a part of the film, and when silicon is a main component, the Raman spectrum is shifted to a lower wave number side than 520 cm ^−1. Yes. In X-ray diffraction, diffraction peaks of (111) and (220) that are derived from the silicon crystal lattice are observed. In order to terminate dangling bonds (dangling bonds), hydrogen or halogen is contained at least 1 atomic% or more. SAS is formed by glow discharge decomposition (plasma CVD) of a gas containing silicon. As a gas containing silicon, SiH ₄ , Si ₂ H ₆ , SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , SiF _4, or the like can be used. Further, F ₂ and GeF ₄ may be mixed. The gas containing silicon may be diluted with H ₂ , or H ₂ and one or more kinds of rare gas elements selected from He, Ar, Kr, and Ne. The dilution rate is in the range of 2 to 1000 times, the pressure is in the range of 0.1 Pa to 133 Pa, and the power supply frequency is 1 MHz to 120 MHz, preferably 13 MHz to 60 MHz. The substrate heating temperature is preferably 300 ° C. or lower, and can be formed even at a substrate heating temperature of 100 to 200 ° C. Here, as an impurity element mainly taken in at the time of film formation, impurities derived from atmospheric components such as oxygen, nitrogen, and carbon are preferably 1 × 10 ²⁰ cm ⁻³ or less, and in particular, the oxygen concentration is 5 × 10 5. It is preferable to be ¹⁹ cm ⁻³ or less, preferably 1 × 10 ¹⁹ cm ⁻³ or less. Further, by adding a rare gas element such as helium, argon, krypton, or neon to further promote lattice distortion, stability is improved and a favorable SAS can be obtained. In addition, a SAS layer formed of a hydrogen-based gas may be stacked on a SAS layer formed of a fluorine-based gas as a semiconductor layer.

A typical example of an amorphous semiconductor is hydrogenated amorphous silicon, and a typical example of a crystalline semiconductor is polysilicon. Polysilicon (polycrystalline silicon) is mainly made of so-called high-temperature polysilicon using polysilicon formed through a process temperature of 800 ° C. or higher as a main material, or polysilicon formed at a process temperature of 600 ° C. or lower. And so-called low-temperature polysilicon, and polysilicon crystallized by adding an element that promotes crystallization. Of course, as described above, a semi-amorphous semiconductor or a semiconductor including a crystal phase in a part of the semiconductor layer can also be used.

In the case where a crystalline semiconductor layer is used for the semiconductor layer, a method for manufacturing the crystalline semiconductor layer can be selected from various methods (laser crystallization method, thermal crystallization method, or heat using an element that promotes crystallization such as nickel. A crystallization method or the like may be used. In addition, a microcrystalline semiconductor that is a SAS can be crystallized by laser irradiation to improve crystallinity. In the case where an element for promoting crystallization is not introduced, the amorphous silicon film is heated at 500 ° C. for 1 hour in a nitrogen atmosphere before irradiating the amorphous silicon film with laser light, whereby the concentration of hydrogen contained in the amorphous silicon film is set to 1 ×. Release to 10 ²⁰ atoms / cm ³ or less. This is because the amorphous silicon film is destroyed when the amorphous silicon film containing a large amount of hydrogen is irradiated with laser light.

The method of introducing the metal element into the amorphous semiconductor layer is not particularly limited as long as the metal element can be present on the surface of the amorphous semiconductor layer or inside the amorphous semiconductor layer. For example, sputtering, CVD, A plasma treatment method (including a plasma CVD method), an adsorption method, or a method of applying a metal salt solution can be used. Among these, the method using a solution is simple and useful in that the concentration of the metal element can be easily adjusted. At this time, in order to improve the wettability of the surface of the amorphous semiconductor layer and to spread the aqueous solution over the entire surface of the amorphous semiconductor layer, irradiation with UV light in an oxygen atmosphere, thermal oxidation method, hydroxy radical It is desirable to form an oxide film by treatment with ozone water or hydrogen peroxide.

The crystallization of the amorphous semiconductor layer may be a combination of heat treatment and crystallization by laser light irradiation, or may be performed multiple times by heat treatment or laser light irradiation alone.

Alternatively, the crystalline semiconductor layer may be directly formed over the substrate by a plasma method. Alternatively, the crystalline semiconductor layer may be selectively formed over the substrate by a linear plasma method.

As a semiconductor, an organic semiconductor material can be used and formed by a printing method, a dispenser method, a spray method, a spin coating method, a droplet discharge method, or the like. In this case, the number of processes can be reduced because the etching process is not necessary. As the organic semiconductor, a low molecular material such as pentacene, a polymer material, or the like is used, and materials such as an organic dye or a conductive polymer material can also be used. The organic semiconductor material used in the present invention is preferably a π-electron conjugated polymer material whose skeleton is composed of conjugated double bonds. Typically, a soluble polymer material such as polythiophene, polyfluorene, poly (3-alkylthiophene), or a polythiophene derivative can be used.

In addition, as an organic semiconductor material that can be used in the present invention, there is a material that can form a semiconductor layer by processing after forming a soluble precursor. Examples of such an organic semiconductor material include polythienylene vinylene, poly (2,5-thienylene vinylene), polyacetylene, a polyacetylene derivative, and polyarylene vinylene.

When converting the precursor into an organic semiconductor, a reaction catalyst such as hydrogen chloride gas is added as well as heat treatment. Typical solvents for dissolving these soluble organic semiconductor materials include toluene, xylene, chlorobenzene, dichlorobenzene, anisole, chloroform, dichloromethane, γ-butyllactone, butyl cellosolve, cyclohexane, N-methyl-2-pyrrolidone. (NMP), cyclohexanone, 2-butanone, dioxane, dimethylformamide (DMF), THF (tetrahydrofuran), or the like can be applied.

In this embodiment mode, a semiconductor layer and a semiconductor layer having one conductivity type are formed by forming a semiconductor film which is a light absorption film over a transfer substrate and then selectively processing the transferred substrate into a desired shape with a laser beam. Then transpose and form. A semiconductor film, which is a light absorption film, is formed over the substrate 114 by a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method (Chemical Vapor Deposition) such as a plasma CVD method, or the like. To do.

A light absorption film is formed over the substrate 114 which is a transfer substrate, and the substrate 114 and the substrate 100 are disposed so as to face each other so that the substrate 100 which is a transfer substrate and the light absorption film are inside.

From the substrate 114 side, the light absorption film is selectively irradiated with the laser beams 115a and 115b through the substrate 114. The light absorption films in the regions irradiated with the laser beams 115a and 115b absorb the laser beams 115a and 115b, and the semiconductor layers 110a, 110b, 111a, and 111b having one conductivity type are formed on the substrate 100 side by energy such as heat. Transposed. On the other hand, the regions not irradiated with the laser beams 115a and 115b remain on the substrate 114 side as the light absorption films 113a to 113f. Similarly to the semiconductor layer having one conductivity type, the semiconductor layers 108 and 109 can be formed by a transposition method using laser light. In this manner, the light absorption film is selectively transferred to selectively form the semiconductor layers 108 and 109 and the semiconductor layers 110a, 110b, 111a, and 111b having one conductivity type without using a photolithography process. (See FIGS. 10A to 10C).

After the transfer with the laser beam, the light absorption layer may be subjected to heat treatment or may be irradiated with the laser beam.

A light-absorbing film that is a transposed object is formed using a material that absorbs irradiated light, and the substrate 114 is a light-transmitting substrate that transmits the irradiated light. When the present invention is used, the substrate can be freely transferred to various substrates, so that the range of substrate material selectivity is widened. In addition, an inexpensive material can be selected as the substrate, so that not only a wide function can be provided depending on the application, but also a display device can be manufactured at low cost.

In this embodiment, amorphous semiconductor layers are formed as the semiconductor layers 108 and 109 and the semiconductor layers 110a, 110b, 111a, and 111b having one conductivity type. In this embodiment, an n-type semiconductor film containing phosphorus (P) which is an impurity element imparting n-type conductivity is formed as the semiconductor film having one conductivity type. A semiconductor film having one conductivity type functions as a source region and a drain region. A semiconductor film having one conductivity type may be formed as necessary, and includes an n-type semiconductor film having an impurity element imparting n-type (P, As) and an impurity element imparting p-type (B). A p-type semiconductor film can be formed.

Source or drain electrode layers 116, 117, 118, and 119 are formed over the substrate 100. The source electrode layer 116, 117, 118, and 119 are made of Ag (silver), Au (gold), Cu (copper), W (tungsten), Al (aluminum), Mo (molybdenum), and Ta (tantalum). An element selected from Ti (titanium) or an alloy material or a compound material containing the element as a main component can be used. Alternatively, light-transmitting indium tin oxide (ITO), indium tin oxide containing silicon oxide (ITSO), organic indium, organic tin, zinc oxide, titanium nitride, or the like may be combined.

The source or drain electrode layers 116, 117, 118, and 119 are formed by a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method (Chemical Vapor Deposition) such as a plasma CVD method, or the like. And can be formed by processing using a mask layer. In addition, a method in which the composition can be transferred or drawn in a desired pattern, for example, various printing methods (screen (stencil) printing, offset (flat plate) printing, letterpress printing, gravure (intaglio printing), etc.) ), A droplet discharge method, a dispenser method, a selective coating method, and the like can also be used.

The conductive film may be processed by dry etching or wet etching. Using an ICP (Inductively Coupled Plasma) etching method, the etching conditions (the amount of power applied to the coil-type electrode, the amount of power applied to the substrate-side electrode, the electrode temperature on the substrate side, etc.) are appropriately set. By adjusting, the electrode layer can be etched into a tapered shape. As an etching _gas, using Cl _2, BCl 3, SiCl ₄ or a chlorine-based gas typified by CCl _4, fluorine-based gas or _{O 2} and typified by CF 4, SF ₆ or NF ₃ as appropriate be able to.

In this embodiment mode, the source electrode layer or the drain electrode layer is formed by forming a conductive film that is a light absorption film over the transfer substrate and then selectively processing the transferred electrode into a desired shape with a laser beam. To do. A light absorption film is formed over the substrate 121 by a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method (Chemical Vapor Deposition) such as a plasma CVD method, or the like.

A light absorption film is formed on the substrate 121 which is a transfer substrate, and the substrate 121 and the substrate 100 are disposed so as to face each other so that the substrate 100 which is a transfer substrate and the light absorption film are inside.

From the substrate 121 side, the light absorbing film is selectively irradiated with laser beams 122a, 122b, 122c, and 122d through the substrate 121. The light absorption film in the region irradiated with the laser beams 122a, 122b, 122c, and 122d absorbs the laser beams 122a, 122b, 122c, and 122d, and the source electrode layer or the drain electrode layer on the substrate 100 side by energy such as heat. 116, 117, 118, and 119 are transposed. On the other hand, the regions not irradiated with the laser beams 122a, 122b, 122c, and 122d remain on the substrate 121 side as light absorption films 120a, 120b, 120c, 120d, 120e, and 120f. In this manner, the light absorption film is selectively transferred, and the source or drain electrode layers 116, 117, 118, and 119 are selectively formed to have a desired shape without using a photolithography process ( (See FIGS. 11A to 11C.)

After the transfer with the laser beam, the light absorption layer may be subjected to heat treatment or may be irradiated with the laser beam.

A light-absorbing film that is a transposed material is formed using a light-absorbing material, and the substrate 121 is a light-transmitting substrate that transmits the irradiated light. When the present invention is used, the substrate can be freely transferred to various substrates, so that the range of substrate material selectivity is widened. In addition, an inexpensive material can be selected as the substrate, so that not only a wide function can be provided depending on the application, but also a display device can be manufactured at low cost.

The source or drain electrode layer 116 also functions as a source wiring layer, and the source or drain electrode layer 118 also functions as a power supply line.

In the opening 107 formed in the gate insulating layer 105, the source or drain electrode layer 117 and the gate electrode layer 104 are electrically connected. A part of the source or drain electrode layer 118 forms a capacitor.

Through the above steps, transistors 139a and 139b which are inverted staggered thin film transistors are manufactured (see FIGS. 11A to 11C).

An insulating layer 123 is formed over the gate insulating layer 105 and the transistors 139a and 139b.

The insulating layer 123 can be formed by a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method such as a plasma CVD method (Chemical Vapor Deposition), or the like. Further, a droplet discharge method, a printing method (a method for forming a pattern such as screen printing or offset printing), a coating method such as a spin coating method, a dipping method, a dispenser method, or the like can also be used.

The insulating layer 123 is formed using silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, aluminum oxynitride, diamond-like carbon (DLC), nitrogen-containing carbon (CN), polysilazane, or other inorganic insulating materials. It can be formed of a material selected from Further, a material containing siloxane may be used. Further, an organic insulating material may be used, and as the organic material, polyimide, acrylic, polyamide, polyimide amide, resist, or benzocyclobutene can be used. Moreover, an oxazole resin can also be used, for example, photocurable polybenzoxazole or the like can be used.

Next, an opening 125 is formed in the insulating layer 123. In this embodiment mode, the opening 125 is formed using laser light as described in Embodiment Mode 1. The source electrode layer or drain electrode layer 119 is selectively irradiated with laser light 124 from the insulating layer 123 side, and the insulating layer 123 on the irradiation region of the source electrode layer or drain electrode layer 119 is removed by the irradiated energy, so that an opening is formed. 125 can be formed (see FIGS. 12A to 12C).

A first electrode layer 126 of a light-emitting element functioning as a pixel electrode is formed in the opening 125 from which the source or drain electrode layer 119 is exposed. The source or drain electrode layer 119 and the first electrode layer 126 are Can be electrically connected.

As shown in Embodiment Mode 3, the first electrode layer 126 is selectively processed into a desired shape on the transferred substrate by irradiating the transferred substrate with a laser beam after forming a conductive light absorption film on the transferred substrate. May be formed.

In this embodiment mode, the first electrode layer is formed by forming a conductive film and then processing it into a desired shape using a mask layer.

The first electrode layer 126 can be formed by a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method such as a plasma CVD method (Chemical Vapor Deposition), or the like. As a conductive material for forming the first electrode layer 126, indium tin oxide (ITO), indium tin oxide containing silicon oxide (ITSO), zinc oxide (ZnO), or the like can be used. More preferably, indium tin oxide containing silicon oxide is used by a sputtering method using a target containing 2 to 10% by weight of silicon oxide in ITO. In addition, a conductive material obtained by doping ZnO with gallium (Ga), and an oxide conductive material formed using a target containing silicon oxide and indium oxide mixed with 2 to 20 wt% zinc oxide (ZnO). Indium zinc oxide (IZO (indium zinc oxide)) may be used.

For the mask layer, a resin material such as an epoxy resin, a phenol resin, a novolac resin, an acrylic resin, a melamine resin, or a urethane resin is used. Also, benzocyclobutene, parylene, fluorinated arylene ether, organic materials such as permeable polyimide, compound materials made by polymerization of siloxane polymers, composition materials containing water-soluble homopolymers and water-soluble copolymers Etc. are formed by a droplet discharge method. Alternatively, a commercially available resist material containing a photosensitizer may be used, and for example, a positive resist or a negative resist may be used. Regardless of which material is used, its surface tension and viscosity are appropriately adjusted by adjusting the concentration of the solvent, adding a surfactant or the like.

The first electrode layer 126 may be processed by dry etching or wet etching. Using an ICP (Inductively Coupled Plasma) etching method, the etching conditions (the amount of power applied to the coil-type electrode, the amount of power applied to the substrate-side electrode, the electrode temperature on the substrate side, etc.) are appropriately set. By adjusting, the electrode layer can be etched into a tapered shape. As an etching _gas, using Cl _2, BCl 3, SiCl ₄ or a chlorine-based gas typified by CCl _4, fluorine-based gas or _{O 2} and typified by CF 4, SF ₆ or NF ₃ as appropriate be able to.

The first electrode layer 126 may be cleaned and polished with a CMP method or a polyvinyl alcohol-based porous body so that the surface thereof is planarized. Further, after the polishing using the CMP method, the surface of the first electrode layer 126 may be subjected to ultraviolet irradiation, oxygen plasma treatment, or the like.

Through the above process, a TFT substrate for a display panel in which the bottom gate TFT and the first electrode layer 126 are connected to the substrate 100 is completed. The TFT of this embodiment mode is an inverted stagger type.

Next, an insulating layer 131 (also referred to as a partition wall) is selectively formed. The insulating layer 131 is formed over the first electrode layer 126 so as to have an opening. In this embodiment mode, the insulating layer 131 is formed over the entire surface, and is etched and processed with a mask such as a resist. When the insulating layer 131 is formed using a droplet discharge method, a printing method, a dispenser method, or the like that can be directly and selectively formed, the processing by etching is not necessarily required.

The insulating layer 131 is formed using silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, aluminum oxynitride, or other inorganic insulating materials, acrylic acid, methacrylic acid, and derivatives thereof, polyimide, aromatic, or aromatic. Bonded to heat-resistant polymers such as polyamide, polybenzimidazole, or inorganic siloxanes containing Si-O-Si bonds among silicon, oxygen, and hydrogen compounds formed from siloxane-based materials as starting materials It can be formed of an organic siloxane insulating material in which hydrogen is substituted with an organic group such as methyl or phenyl. You may form using photosensitive and non-photosensitive materials, such as an acryl and a polyimide. The insulating layer 131 preferably has a shape in which the radius of curvature continuously changes, and the coverage of the electroluminescent layer 132 and the second electrode layer 133 formed thereon is improved.

Alternatively, after the insulating layer 131 is formed by discharging a composition by a droplet discharge method, the surface may be pressed and flattened by pressure in order to improve the flatness. As a pressing method, unevenness may be reduced by scanning a roller-shaped object on the surface, or the surface may be pressed vertically with a flat plate-like object. Alternatively, the surface may be softened or melted with a solvent or the like, and the surface irregularities may be removed with an air knife. Further, polishing may be performed using a CMP method. This step can be applied when the surface is flattened when unevenness is generated by the droplet discharge method. When flatness is improved by this step, display unevenness of the display panel can be prevented and a high-definition image can be displayed.

A light emitting element is formed over a substrate 100 which is a TFT substrate for a display panel (see FIGS. 14A and 14B).

Before the electroluminescent layer 132 is formed, heat treatment is performed at 200 ° C. under atmospheric pressure to remove moisture adsorbed in the first electrode layer 134 and the insulating layer 131 or on the surface thereof. Further, it is preferable to perform heat treatment at 200 to 400 ° C. under reduced pressure, preferably 250 to 350 ° C., and form the electroluminescent layer 132 by vacuum deposition or droplet discharge under reduced pressure without being exposed to the air as it is. .

As the electroluminescent layer 132, materials that emit red (R), green (G), and blue (B) light are selectively formed by an evaporation method using an evaporation mask or the like. A material that emits red (R), green (G), and blue (B) light can be formed by a droplet discharge method (such as a low-molecular or high-molecular material) in the same manner as a color filter. In this case, a mask is not used. Both are preferable because RGB can be separately applied. A second electrode layer 133 is stacked over the electroluminescent layer 132 to complete a display device having a display function using a light emitting element.

Although not shown, it is effective to provide a passivation film so as to cover the second electrode layer 133. A passivation (protective) film provided when a display device is formed may have a single layer structure or a multilayer structure. As the passivation film, silicon nitride (SiN), silicon oxide (SiO ₂ ), silicon oxynitride (SiON), silicon nitride oxide (SiNO), aluminum nitride (AlN), aluminum oxynitride (AlON), nitrogen content is oxygen It is made of an insulating film containing aluminum nitride oxide (AlNO) or aluminum oxide, diamond-like carbon (DLC), or nitrogen-containing carbon (CN _X ) that is higher than the content, and a single layer or a combination of the insulating films is used. it can. For example, a laminate such as a nitrogen-containing carbon film (CN _x ) or silicon nitride (SiN), or an organic material can be used, or a laminate of polymers such as styrene polymer may be used. A siloxane material may also be used.

At this time, it is preferable to use a film with good coverage as the passivation film, and it is effective to use a carbon film, particularly a DLC film. Since the DLC film can be formed in a temperature range from room temperature to 100 ° C., it can be easily formed over the electroluminescent layer having low heat resistance. The DLC film is formed by a plasma CVD method (typically, an RF plasma CVD method, a microwave CVD method, an electron cyclotron resonance (ECR) CVD method, a hot filament CVD method, etc.), a combustion flame method, a sputtering method, or an ion beam evaporation method. It can be formed by laser vapor deposition. The reaction gas used for film formation was hydrogen gas and a hydrocarbon-based gas (for example, CH ₄ , C ₂ H ₂ , C ₆ H _6, etc.), ionized by glow discharge, and negative self-bias was applied. Films are formed by accelerated collision of ions with the cathode. The CN film may be formed using C ₂ H ₄ gas and N ₂ gas as reaction gases. The DLC film has a high blocking effect against oxygen and can suppress oxidation of the electroluminescent layer. Therefore, the problem that the electroluminescent layer is oxidized during the subsequent sealing process can be prevented.

A sealing material is formed and sealed using a sealing substrate. After that, a flexible wiring board may be connected to a gate wiring layer formed by being electrically connected to the gate electrode layer 103 to be electrically connected to the outside. The same applies to the source wiring layer formed by being electrically connected to the source or drain electrode layer 116 which is also the source wiring layer.

A filler is sealed between the substrate 100 having elements and the sealing substrate. A dripping method can also be used to enclose the filler. Instead of the filler, an inert gas such as nitrogen may be filled. Further, by installing the desiccant in the display device, the light emitting element can be prevented from being deteriorated by moisture. The installation place of the desiccant may be on the sealing substrate side or the substrate 100 side having elements, and may be installed with a recess formed in the substrate in the region where the sealing material is formed. In addition, when it is installed at a location corresponding to a region that does not contribute to display, such as a drive circuit region or a wiring region of a sealing substrate, the aperture ratio is not lowered even if the desiccant is an opaque substance. The filler may be formed so as to include a hygroscopic material, and may have a function of a desiccant. Thus, a display device having a display function using a light-emitting element is completed.

In this embodiment mode, the switching TFT has a single gate structure, but a multi-gate structure such as a double gate structure may be used. In the case where a semiconductor is manufactured using a SAS or a crystalline semiconductor, an impurity region can be formed by adding an impurity imparting one conductivity type. In this case, the semiconductor layer may have impurity regions having different concentrations. For example, the vicinity of the channel region of the semiconductor layer and the region stacked with the gate electrode layer may be low-concentration impurity regions, and the outer region may be high-concentration impurity regions.

This embodiment mode can be combined with any of Embodiment Modes 1 to 3 as appropriate.

According to the present invention, a component such as a wiring constituting the display device can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

(Embodiment 5)
In this embodiment, an example of a display device which has high reliability and is manufactured at a low cost through a simplified process will be described. Specifically, a light-emitting display device using a light-emitting element as a display element will be described. A method for manufacturing the display device in this embodiment will be described in detail with reference to FIGS.

Silicon nitride oxide by a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method (Chemical Vapor Deposition) such as a plasma CVD method, or the like as a base film over a substrate 150 having an insulating surface. A base film 151a is formed to 10 to 200 nm (preferably 50 to 150 nm) using the film, and a base film 151b is stacked to 50 to 200 nm (preferably 100 to 150 nm) using a silicon oxynitride film. Alternatively, heat-resistant polymers such as acrylic acid, methacrylic acid and derivatives thereof, polyimide, aromatic polyamide, polybenzimidazole, or siloxane resin may be used. Moreover, resin materials such as vinyl resins such as polyvinyl alcohol and polyvinyl butyral, epoxy resins, phenol resins, novolac resins, acrylic resins, melamine resins, and urethane resins may be used. Alternatively, an organic material such as benzocyclobutene, parylene, fluorinated arylene ether, or polyimide, a composition material containing a water-soluble homopolymer and a water-soluble copolymer, or the like may be used. Moreover, an oxazole resin can also be used, for example, photocurable polybenzoxazole or the like can be used.

Further, a droplet discharge method, a printing method (a method for forming a pattern such as screen printing or offset printing), a coating method such as a spin coating method, a dipping method, a dispenser method, or the like can also be used. In this embodiment, the base film 151a and the base film 151b are formed by a plasma CVD method. As the substrate 150, a glass substrate, a quartz substrate, a silicon substrate, a metal substrate, or a stainless substrate on which an insulating film is formed may be used. Further, a plastic substrate having heat resistance that can withstand the processing temperature of this embodiment may be used, or a flexible substrate such as a film may be used. As the plastic substrate, a substrate made of PET (polyethylene terephthalate), PEN (polyethylene naphthalate), or PES (polyethersulfone) can be used, and as the flexible substrate, a synthetic resin such as acrylic can be used. Since the display device manufactured in this embodiment has a structure in which light from the light-emitting element is extracted through the substrate 150, the substrate 150 needs to have a light-transmitting property.

As the base film, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, or the like can be used, and a single layer or a laminated structure of two layers or three layers may be used.

Next, a semiconductor film is formed over the base film. The semiconductor film may be formed by various means (a sputtering method, an LPCVD method, a plasma CVD method, or the like) with a thickness of 25 to 200 nm (preferably 30 to 150 nm). In this embodiment mode, it is preferable to use a crystalline semiconductor film obtained by crystallizing an amorphous semiconductor film by laser crystallization.

In order to control the threshold voltage of the thin film transistor, the semiconductor film thus obtained may be doped with a trace amount of impurity element (boron or phosphorus). This doping of the impurity element may be performed on the amorphous semiconductor film before the crystallization step. When the impurity element is doped in the state of the amorphous semiconductor film, the impurity can be activated by heat treatment for subsequent crystallization. In addition, defects and the like generated during doping can be improved.

Next, the crystalline semiconductor film is etched into a desired shape to form a semiconductor layer.

As the etching process, either plasma etching (dry etching) or wet etching may be employed, but plasma etching is suitable for processing a large area substrate. As an etching gas, a fluorine-based gas such as CF ₄ or NF ₃ or a chlorine-based gas such as Cl ₂ or BCl ₃ may be used, and an inert gas such as He or Ar may be appropriately added. Further, if an atmospheric pressure discharge etching process is applied, a local electric discharge process is also possible, and it is not necessary to form a mask layer on the entire surface of the substrate.

In the present invention, a conductive layer for forming a wiring layer or an electrode layer, a mask layer for forming a predetermined pattern, or the like may be formed by a method capable of selectively forming a pattern such as a droplet discharge method. . A droplet discharge (ejection) method (also called an ink-jet method depending on the method) is a method in which a droplet of a composition prepared for a specific purpose is selectively ejected (ejection) to form a predetermined pattern (such as a conductive layer or a conductive layer). An insulating layer or the like can be formed. At this time, a process for controlling wettability and adhesion may be performed on the formation region. In addition, a method by which the pattern can be transferred (transferred) or drawn, for example, a printing method (a method for forming a pattern such as screen printing or offset printing), a dispenser method, or the like can also be used.

A gate insulating layer is formed to cover the semiconductor layer. The gate insulating layer is formed of an insulating film containing silicon with a thickness of 10 to 150 nm using a plasma CVD method or a sputtering method. The gate insulating layer may be formed using a material such as silicon nitride, silicon oxide, silicon oxynitride, or silicon oxide or nitride material typified by silicon nitride oxide, and may be a stacked layer or a single layer. Further, the insulating layer may be a three-layer stack of a silicon nitride film, a silicon oxide film, and a silicon nitride film, or a stack of a single layer and two layers of a silicon oxynitride film.

Next, a gate electrode layer is formed over the gate insulating layer. The gate electrode layer can be formed by a technique such as sputtering, vapor deposition, or CVD. The gate electrode layer is an element selected from tantalum (Ta), tungsten (W), titanium (Ti), molybdenum (Mo), aluminum (Al), copper (Cu), chromium (Cr), neodymium (Nd), or What is necessary is just to form with the alloy material or compound material which has the said element as a main component. Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus, or an AgPdCu alloy may be used for the gate electrode layer. The gate electrode layer may be a single layer or a stacked layer.

In this embodiment mode, the gate electrode layer is formed to have a tapered shape; however, the present invention is not limited thereto, and the gate electrode layer has a stacked structure, and only one layer has a tapered shape, and the other is anisotropic. You may have a vertical side surface by an etching. As in this embodiment, the taper angle may be different between the stacked gate electrode layers, or may be the same. By having a tapered shape, the coverage of a film stacked thereon is improved and defects are reduced, so that reliability is improved.

The gate insulating layer may be slightly etched by the etching process when forming the gate electrode layer, and the film thickness may be reduced (so-called film reduction).

An impurity element is added to the semiconductor layer to form an impurity region. The impurity region can be a high concentration impurity region and a low concentration impurity region by controlling the concentration thereof. A thin film transistor having a low-concentration impurity region is referred to as an LDD (Lightly Doped Drain) structure. The low-concentration impurity region can be formed so as to overlap with the gate electrode. Such a thin film transistor is referred to as a GOLD (Gate Overlapped LDD) structure. The polarity of the thin film transistor is n-type by using phosphorus (P) or the like in the impurity region. When p-type is used, boron (B) or the like may be added.

In this embodiment, a region where the impurity region overlaps with the gate electrode layer through the gate insulating layer is referred to as a Lov region, and a region where the impurity region does not overlap with the gate electrode layer through the gate insulating layer is referred to as a Loff region. In FIG. 15, hatching and white background are shown in the impurity region, but this does not indicate that the impurity element is not added to the white background portion, but the concentration distribution of the impurity element in this region is mask or doping. This is because it is possible to intuitively understand that the conditions are reflected. This also applies to other drawings in this specification.

In order to activate the impurity element, heat treatment, intense light irradiation, or laser light irradiation may be performed. Simultaneously with activation, plasma damage to the gate insulating layer and plasma damage to the interface between the gate insulating layer and the semiconductor layer can be recovered.

Next, a first interlayer insulating layer is formed to cover the gate electrode layer and the gate insulating layer. In this embodiment mode, a stacked structure of the insulating film 167 and the insulating film 168 is employed. As the insulating film 167 and the insulating film 168, a silicon nitride film, a silicon nitride oxide film, a silicon oxynitride film, a silicon oxide film, or the like using a sputtering method or plasma CVD can be used, and another insulating film containing silicon can be used. A single layer or a stacked structure of three or more layers may be used.

Further, a heat treatment is performed at 300 to 550 ° C. for 1 to 12 hours in a nitrogen atmosphere to perform a step of hydrogenating the semiconductor layer. Preferably, it carries out at 400-500 degreeC. This step is a step of terminating dangling bonds in the semiconductor layer with hydrogen contained in the insulating film 167 which is an interlayer insulating layer. In this embodiment, heat treatment is performed at 410 degrees (° C.).

In addition, as the insulating films 167 and 168, aluminum nitride (AlN), aluminum oxynitride (AlON), aluminum nitride oxide (AlNO) or aluminum oxide in which the nitrogen content is higher than the oxygen content, diamond like carbon (DLC) , Nitrogen-containing carbon (CN), polysilazane, and other materials including inorganic insulating materials. Further, a material containing siloxane may be used. Further, an organic insulating material may be used, and as the organic material, polyimide, acrylic, polyamide, polyimide amide, resist, or benzocyclobutene can be used. Moreover, an oxazole resin can also be used, for example, photocurable polybenzoxazole or the like can be used.

Next, contact holes (openings) reaching the semiconductor layer are formed in the insulating film 167, the insulating film 168, and the gate insulating layer.

In this embodiment mode, an opening is formed using laser light as described in Embodiment Mode 1. The source region and the drain region of the semiconductor layer are selectively irradiated with laser light from the insulating film 167 and the insulating film 168 side, and the insulating film 167 on the irradiation region of the source region and the drain region of the semiconductor layer is insulated by the irradiated energy. The film 168 and the gate insulating layer are removed, so that an opening can be formed.

A source electrode layer or a drain electrode layer is formed in the opening in which the source region and the drain region of the semiconductor layer are exposed, and the source region and the drain region of the semiconductor layer are electrically connected to the source electrode layer or the drain electrode layer. it can.

The source electrode layer or the drain electrode layer can be formed by forming a conductive film by a PVD method, a CVD method, an evaporation method, or the like, and then processing it into a desired shape. In addition, a conductive layer can be selectively formed at a predetermined place by a droplet discharge method, a printing method, a dispenser method, an electrolytic plating method, or the like. Furthermore, a reflow method or a damascene method may be used. The material of the source electrode layer or the drain electrode layer is Ag, Au, Cu, Ni, Pt, Pd, Ir, Rh, W, Al, Ta, Mo, Cd, Zn, Fe, Ti, Si, Ge, Zr, Ba Or a metal nitride thereof or a metal nitride thereof. Moreover, it is good also as these laminated structures.

As shown in Embodiment Mode 3, a light-absorbing film using a conductive material or a semiconductor material for a gate electrode layer, a semiconductor layer, a source electrode layer, and a drain electrode layer included in the display device described in this embodiment mode After the film is formed, it can be selectively processed into a desired shape by being irradiated with a laser beam. Accordingly, since a photolithography process is not used, the process can be simplified and material loss can be prevented, so that cost reduction can be achieved.

Through the above steps, the peripheral driver circuit region 204 includes a thin film transistor 285 which is a p-channel thin film transistor having a p-type impurity region in the Lov region, and a thin film transistor 275 which is an n-channel thin film transistor having an n-channel impurity region in the Lov region. In 206, an active matrix substrate having a thin film transistor 265 which is a multi-channel n-channel thin film transistor having an n-type impurity region in a Loff region and a thin film transistor 255 which is a p-channel thin film transistor having a p-type impurity region in a Lov region is manufactured. Can do.

Without being limited to this embodiment mode, the thin film transistor may have a single gate structure in which one channel formation region is formed, a double gate structure in which two channel formation regions are formed, or a triple gate structure in which three channel formation regions are formed. The thin film transistor in the peripheral driver circuit region may have a single gate structure, a double gate structure, or a triple gate structure.

Next, an insulating film 181 is formed as a second interlayer insulating layer. In FIG. 15, there are a separation region 201 for separation by scribing, an external terminal connection region 202 that is an FPC pasting portion, a wiring region 203 that is a peripheral wiring region, a peripheral driver circuit region 204, and a pixel region 206. . The wiring region 203 is provided with wirings 179a and 179b, and the external terminal connection region 202 is provided with a terminal electrode layer 178 that is connected to an external terminal.

As the insulating film 181, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, aluminum nitride (AlN), aluminum oxide containing nitrogen (also referred to as aluminum oxynitride) (AlON), aluminum nitride containing oxygen (aluminum nitride oxide) (Also) (AlNO), aluminum oxide, diamond like carbon (DLC), nitrogen-containing carbon film (CN), phosphorus glass (PSG), phosphorus boron glass (BPSG), alumina film, polysilazane, and other inorganic insulating materials It can be formed of a material selected from the containing substances. A siloxane resin may also be used. An organic insulating material may be used, and the organic material may be either photosensitive or non-photosensitive. Polyimide, acrylic, polyamide, polyimide amide, resist or benzocyclobutene, low dielectric constant (Low-k) Materials can be used. Moreover, an oxazole resin can also be used, for example, photocurable polybenzoxazole or the like can be used. An interlayer insulating layer provided for planarization is required to have high heat resistance and high insulation and a high planarization rate. Therefore, a method for forming the insulating film 181 is represented by a spin coating method. It is preferable to use a coating method.

The insulating film 181 may employ other dipping methods, spray coating, doctor knife, roll coater, curtain coater, knife coater, CVD method, vapor deposition method, and the like. The insulating film 181 may be formed by a droplet discharge method. When the droplet discharge method is used, the material liquid can be saved. Further, a method capable of transferring or drawing a pattern, such as a droplet discharge method, for example, a printing method (a method for forming a pattern such as screen printing or offset printing), a dispenser method, or the like can be used.

A fine opening, that is, a contact hole is formed in the insulating film 181 in the pixel region 206. The source electrode layer or the drain electrode layer is electrically connected to the first electrode layer 185 through an opening formed in the insulating film 181. The opening formed in the insulating film 181 can be formed by irradiation with laser light as described in Embodiment Mode 1. In this embodiment, a low-melting-point metal (chromium in this embodiment) that is relatively easily evaporated is used for the source electrode layer or the drain electrode layer. The source electrode layer or the drain electrode layer is selectively irradiated with laser light from the insulating film 181 side, and the insulating film 181 on the irradiation region of the source electrode layer or the drain electrode layer is removed by the irradiated energy to form an opening. be able to. The first electrode layer 185 is formed in the opening from which the source or drain electrode layer is exposed, and the source or drain electrode layer and the first electrode layer 185 can be electrically connected.

The first electrode layer 185 functions as an anode or a cathode and is an element selected from Ti, Ni, W, Cr, Pt, Zn, Sn, In, or Mo, or titanium nitride, TiSi _X N _Y , WSi _X , Tungsten nitride, WSi _X N _Y , NbN, or the like, a film mainly containing an alloy material or compound material containing the above elements as a main component, or a stacked film thereof may be used in a total film thickness range of 100 nm to 800 nm.

In this embodiment, a light-emitting element is used as a display element and light from the light-emitting element is extracted from the first electrode layer 185 side; thus, the first electrode layer 185 has a light-transmitting property. A transparent conductive film is formed as the first electrode layer 185, and the first electrode layer 185 is formed by etching into a desired shape.

In the present invention, a transparent conductive film made of a light-transmitting conductive material may be used for the first electrode layer 185 that is a light-transmitting electrode layer, indium oxide containing tungsten oxide, Indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, or the like can be used. Needless to say, indium tin oxide (ITO), indium zinc oxide (IZO), indium tin oxide added with silicon oxide (ITSO), or the like can also be used.

Further, even when a material such as a metal film that does not have translucency is used, the first film thickness can be reduced by thinning (preferably about 5 nm to 30 nm) so that light can be transmitted. It becomes possible to emit light from the electrode layer 185. As the metal thin film that can be used for the first electrode layer 185, a conductive film made of titanium, tungsten, nickel, gold, platinum, silver, aluminum, magnesium, calcium, lithium, or an alloy thereof is used. Can do.

The first electrode layer 185 can be formed by an evaporation method, a sputtering method, a CVD method, a printing method, a dispenser method, a droplet discharge method, or the like. In this embodiment, the first electrode layer 185 is formed by a sputtering method using indium zinc oxide containing tungsten oxide. The first electrode layer 185 is preferably used in a total film thickness range of 100 nm to 800 nm. As shown in Embodiment Mode 3, the first electrode layer 185 is selectively processed into a desired shape on the transferred substrate by irradiating the transferred substrate with a laser light after forming a conductive light absorption film on the transferred substrate. May be formed.

The first electrode layer 185 may be wiped with a CMP method or a polyvinyl alcohol-based porous material and polished so that the surface thereof is planarized. Further, after polishing using the CMP method, the surface of the first electrode layer 185 may be subjected to ultraviolet irradiation, oxygen plasma treatment, or the like.

Heat treatment may be performed after the first electrode layer 185 is formed. By this heat treatment, moisture contained in the first electrode layer 185 is released. Therefore, the first electrode layer 185 does not cause degassing. Therefore, even when a light-emitting material that is easily deteriorated by moisture is formed over the first electrode layer, the light-emitting material is not deteriorated and the display device has high reliability. Can be produced.

Next, an insulating layer 186 (referred to as a partition wall, a barrier, or the like) is formed to cover the end portion of the first electrode layer 185 and the source or drain electrode layer.

As the insulating layer 186, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, or the like can be used, and a single layer or a stacked structure of two layers or three layers may be used. As other materials for the insulating layer 186, aluminum nitride, aluminum oxynitride having an oxygen content higher than the nitrogen content, aluminum nitride oxide or aluminum oxide having a nitrogen content higher than the oxygen content, diamond-like carbon (DLC) ), Nitrogen-containing carbon, polysilazane, and other materials including inorganic insulating materials. A material containing siloxane may be used. Further, an organic insulating material may be used, and the organic material may be either photosensitive or non-photosensitive, and polyimide, acrylic, polyamide, polyimide amide, resist, or benzocyclobutene can be used. Moreover, an oxazole resin can also be used, for example, photocurable polybenzoxazole or the like can be used.

The insulating layer 186 is formed by a sputtering method, a PVD method (Physical Vapor Deposition), a low pressure CVD method (LPCVD method), a CVD method such as a plasma CVD method (Chemical Vapor Deposition), or a droplet discharge capable of selectively forming a pattern. It is also possible to use a method, a printing method capable of transferring or drawing a pattern (a method of forming a pattern such as screen printing or offset printing), a coating method such as a dispenser method, a spin coating method, or a dipping method.

As the etching process for processing into a desired shape, either plasma etching (dry etching) or wet etching may be employed. Plasma etching is suitable for processing large area substrates. As an etching gas, a fluorine-based gas such as CF ₄ or NF ₃ or a chlorine-based gas such as Cl ₂ or BCl ₃ may be used, and an inert gas such as He or Ar may be appropriately added. Further, if an atmospheric pressure discharge etching process is applied, a local electric discharge process is also possible, and it is not necessary to form a mask layer on the entire surface of the substrate.

In the connection region 205 illustrated in FIG. 15A, the wiring layer formed of the same material and in the same process as the second electrode layer is electrically connected to the wiring layer of the same process and the same material as the gate electrode layer. To do.

A light emitting layer 188 is formed over the first electrode layer 185. Although only one pixel is shown in FIG. 15, electroluminescent layers corresponding to each color of R (red), G (green), and B (blue) are separately formed in this embodiment.

Next, a second electrode layer 189 made of a conductive film is provided over the light emitting layer 188. As the second electrode layer 189, Al, Ag, Li, Ca, or an alloy or compound thereof such as MgAg, MgIn, AlLi, CaF ₂ , or calcium nitride may be used. Thus, a light-emitting element 190 including the first electrode layer 185, the light-emitting layer 188, and the second electrode layer 189 is formed (see FIG. 15B).

In the display device of this embodiment mode illustrated in FIG. 15, light emitted from the light-emitting element 190 is transmitted through and emitted from the first electrode layer 185 side in the direction of the arrow in FIG.

In this embodiment, an insulating layer may be provided as a passivation film (a protective film) over the second electrode layer 189. Thus, it is effective to provide a passivation film so as to cover the second electrode layer 189. As the passivation film, silicon nitride, silicon oxide, silicon oxynitride, silicon nitride oxide, aluminum nitride, aluminum oxynitride, aluminum nitride oxide or aluminum oxide having a nitrogen content higher than the oxygen content, diamond-like carbon (DLC), It can be formed of an insulating film containing nitrogen-containing carbon, and a single layer or a combination of the insulating films can be used. Alternatively, a siloxane resin may be used.

At this time, it is preferable to use a film with good coverage as the passivation film, and it is effective to use a carbon film, particularly a DLC film. Since the DLC film can be formed in a temperature range from room temperature to 100 ° C., it can be easily formed over the light-emitting layer 188 having low heat resistance. The DLC film is formed by a plasma CVD method (typically, an RF plasma CVD method, a microwave CVD method, an electron cyclotron resonance (ECR) CVD method, a hot filament CVD method, etc.), a combustion flame method, a sputtering method, or an ion beam evaporation method. It can be formed by laser vapor deposition. The reaction gas used for film formation was hydrogen gas and a hydrocarbon-based gas (for example, CH ₄ , C ₂ H ₂ , C ₆ H _6, etc.), ionized by glow discharge, and negative self-bias was applied. Films are formed by accelerated collision of ions with the cathode. The CN film may be formed using C ₂ H ₄ gas and N ₂ gas as reaction gases. The DLC film has a high blocking effect against oxygen and can suppress oxidation of the light-emitting layer 188. Therefore, the problem that the light emitting layer 188 is oxidized during the subsequent sealing process can be prevented.

The substrate 150 over which the light-emitting element 190 is formed in this manner and the sealing substrate 195 are fixed with a sealant 192 to seal the light-emitting element (see FIG. 15). As the sealant 192, it is typically preferable to use a visible light curable resin, an ultraviolet curable resin, or a thermosetting resin. For example, bisphenol A type liquid resin, bisphenol A type solid resin, bromine-containing epoxy resin, bisphenol F type resin, bisphenol AD type resin, phenol type resin, cresol type resin, novolac type resin, cyclic aliphatic epoxy resin, epibis type epoxy Epoxy resins such as resins, glycidyl ester resins, glycidylamine resins, heterocyclic epoxy resins, and modified epoxy resins can be used. Note that a region surrounded by the sealant may be filled with a filler 193, or nitrogen or the like may be sealed by sealing in a nitrogen atmosphere. Since this embodiment mode is a bottom emission type, the filler 193 does not need to have translucency, but in the case of a structure in which light is extracted through the filler 193, the filler 193 needs to have translucency. Typically, a visible light curable, ultraviolet curable, or thermosetting epoxy resin may be used. Through the above steps, a display device having a display function using a light-emitting element in this embodiment is completed. Further, the filler can be dropped in a liquid state and filled in the display device. When a material having hygroscopicity such as a desiccant is used as the filler, a further water absorption effect can be obtained and deterioration of the element can be prevented.

A desiccant is installed in the EL display panel in order to prevent deterioration of the element due to moisture. In this embodiment mode, the desiccant is provided in a recess formed in the sealing substrate so as to surround the pixel region, and the thickness is not hindered. Moreover, if a desiccant is formed also in the area | region corresponding to a gate wiring layer and a water absorption area is taken widely, the water absorption effect will be high. Further, when a desiccant is formed on the gate wiring layer that does not emit light directly, the light extraction efficiency is not lowered.

Note that in this embodiment mode, a case where a light-emitting element is sealed with a glass substrate is shown; however, the sealing process is a process for protecting the light-emitting element from moisture and is mechanically sealed with a cover material. Either a method, a method of encapsulating with a thermosetting resin or an ultraviolet light curable resin, or a method of encapsulating with a thin film having a high barrier ability such as a metal oxide or a nitride is used. As the cover material, glass, ceramics, plastic, or metal can be used. However, when light is emitted to the cover material side, it must be translucent. In addition, the cover material and the substrate on which the light emitting element is formed are bonded together using a sealing material such as a thermosetting resin or an ultraviolet light curable resin, and the resin is cured by heat treatment or ultraviolet light irradiation treatment to form a sealed space. Form. It is also effective to provide a hygroscopic material typified by barium oxide in this sealed space. This hygroscopic material may be provided in contact with the sealing material, or may be provided on the partition wall or in the peripheral portion so as not to block light from the light emitting element. Further, the space between the cover material and the substrate on which the light emitting element is formed can be filled with a thermosetting resin or an ultraviolet light curable resin. In this case, it is effective to add a moisture absorbing material typified by barium oxide in the thermosetting resin or the ultraviolet light curable resin.

In addition, the source electrode layer or the drain electrode layer and the first electrode layer may be in direct contact with each other and may be connected via a wiring layer without being electrically connected.

In this embodiment mode, the FPC 194 is connected to the terminal electrode layer 178 with the anisotropic conductive layer 196 in the external terminal connection region 202 so as to be electrically connected to the outside. As shown in FIG. 15A, which is a top view of the display device, the display device manufactured in this embodiment includes a peripheral driver circuit region 204 having a signal line driver circuit and a peripheral driver circuit region 209. A peripheral driving circuit region 207 having a scanning line driving circuit and a peripheral driving circuit region 208 are provided.

In this embodiment mode, the circuit is formed as described above. However, the present invention is not limited to this, and an IC chip may be mounted as a peripheral driver circuit by the above-described COG method or TAB method. Further, the gate line driver circuit and the source line driver circuit may be plural or singular.

In the display device of the present invention, the screen display driving method is not particularly limited. For example, a dot sequential driving method, a line sequential driving method, a surface sequential driving method, or the like may be used. Typically, a line sequential driving method is used, and a time-division gray scale driving method or an area gray scale driving method may be used as appropriate. The video signal input to the source line of the display device may be an analog signal or a digital signal, and a drive circuit or the like may be designed in accordance with the video signal as appropriate.

This embodiment mode can be combined with any of Embodiment Modes 1 to 3 as appropriate.

According to the present invention, a component such as a wiring constituting the display device can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

(Embodiment 6)
A thin film transistor is formed by applying the present invention, and a display device can be formed using the thin film transistor. When a light-emitting element is used and an n-channel transistor is used as a transistor for driving the light-emitting element, The light emitted from the light emitting element emits either downward radiation, upward radiation, or both radiation. Here, a stacked structure of light-emitting elements corresponding to each case will be described with reference to FIGS.

In this embodiment mode, channel protective thin film transistors 461, 471, and 481 to which the present invention is applied are used. The thin film transistor 481 is provided over a light-transmitting substrate 480 and includes a gate electrode layer 493, a gate insulating film 497, a semiconductor layer 494, an n-type semiconductor layer 495a, an n-type semiconductor layer 495b, a source electrode layer, or The drain electrode layer 487a, the source or drain electrode layer 487b, the channel protective layer 496, the insulating layer 499, and the wiring layer 498 are formed. As shown in Embodiment Mode 3, the gate electrode layer, the semiconductor layer, the source electrode layer, the drain electrode layer, and the like are selectively formed by irradiating with a laser beam after forming a light-absorbing film having conductivity on the transfer substrate. The transfer substrate may be processed into a desired shape. Since the process is simplified and material loss can be prevented, cost reduction can be achieved.

17A to 17C described in this embodiment, a contact hole (opening) reaching the source or drain electrode layer 487b is formed in the insulating layer 499.

In this embodiment mode, an opening is formed using laser light as described in Embodiment Mode 1. The source electrode or drain electrode layer 487b is selectively irradiated with laser light from the insulating layer 499 side, and the insulating layer 499 over the irradiation region of the source electrode layer or drain electrode layer 487b is removed by the irradiated energy, so that an opening is formed. Can be formed.

A wiring layer 498 is formed in the opening from which the source or drain electrode layer 487b is exposed, and the source or drain electrode layer 487b and the wiring layer 498 can be electrically connected. Since the wiring layer 498 is formed in contact with the first electrode layer 484 of the light-emitting element, the thin film transistor 481 and the light-emitting element are electrically connected to each other through the wiring layer 498.

In this embodiment mode, an amorphous semiconductor layer is used as the semiconductor layer. However, the present invention is not limited to this embodiment mode, and a crystalline semiconductor layer can be used as a semiconductor layer, and an n-type semiconductor layer can be used as a semiconductor layer of one conductivity type. Instead of forming an n-type semiconductor layer, conductivity may be imparted to the semiconductor layer by performing plasma treatment with a PH ₃ gas. When a crystalline semiconductor layer such as polysilicon is used, an impurity region having one conductivity type may be formed by introducing (adding) an impurity into the crystalline semiconductor layer without forming the one conductivity type semiconductor layer. . In addition, an organic semiconductor such as pentacene can be used. When the organic semiconductor is selectively formed by a droplet discharge method or the like, a processing process can be simplified.

The case where a crystalline semiconductor layer is used as the semiconductor layer is described. First, an amorphous semiconductor layer is crystallized to form a crystalline semiconductor layer. In the crystallization step, an element (also referred to as a catalyst element or a metal element) that promotes crystallization is added to the amorphous semiconductor layer, and crystallization is performed by heat treatment (at 550 ° C. to 750 ° C. for 3 minutes to 24 hours). As elements for promoting crystallization, metal elements for promoting crystallization of silicon include iron (Fe), nickel (Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium (Pd). One or a plurality selected from osmium (Os), iridium (Ir), platinum (Pt), copper (Cu), and gold (Au) can be used.

In order to remove or reduce the element that promotes crystallization from the crystalline semiconductor layer, a semiconductor layer containing an impurity element is formed in contact with the crystalline semiconductor layer and functions as a gettering sink. As the impurity element, an impurity element imparting n-type conductivity, an impurity element imparting p-type conductivity, a rare gas element, or the like can be used. For example, phosphorus (P), nitrogen (N), arsenic (As), antimony (Sb ), Bismuth (Bi), boron (B), helium (He), neon (Ne), argon (Ar), Kr (krypton), and Xe (xenon) can be used. An n-type semiconductor layer is formed over the crystalline semiconductor layer containing an element that promotes crystallization, and heat treatment (at 550 ° C. to 750 ° C. for 3 minutes to 24 hours) is performed. The element that promotes crystallization contained in the crystalline semiconductor layer moves into the n-type semiconductor layer, and the element that promotes crystallization in the crystalline semiconductor layer is removed or reduced, so that the semiconductor layer is formed. Is done. On the other hand, the n-type semiconductor layer becomes an n-type semiconductor layer containing a metal element which is an element that promotes crystallinity, and is then processed into a desired shape to become an n-type semiconductor layer. Thus, the n-type semiconductor layer functions as a gettering sink of the semiconductor layer, and also functions as a source region and a drain region as it is.

The semiconductor layer crystallization step and the gettering step may be performed by a plurality of heat treatments, and the crystallization step and the gettering step may be performed by a single heat treatment. In this case, an amorphous semiconductor layer is formed, an element that promotes crystallization is added, a semiconductor layer serving as a gettering sink is formed, and then heat treatment is performed.

In this embodiment, the gate insulating layer is formed by stacking a plurality of layers, and a silicon nitride oxide film and a silicon oxynitride film are formed as the gate insulating film 497 from the gate electrode layer 493 side to have a two-layer stacked structure. The insulating layers to be stacked are preferably formed continuously while switching the reaction gas at the same temperature without breaking the vacuum in the same chamber. If formed continuously without breaking the vacuum, it is possible to prevent the interface between the stacked films from being contaminated.

For the channel protective layer 496, polyimide, polyvinyl alcohol, or the like may be dropped by a droplet discharge method. As a result, the exposure process can be omitted. As the channel protective layer, inorganic materials (silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, etc.), photosensitive or non-photosensitive organic materials (organic resin materials) (polyimide, acrylic, polyamide, polyimide amide, resist) , Benzocyclobutene, etc.), a low dielectric constant material, or a film made of a plurality of kinds, or a stack of these films can be used. A siloxane material may also be used. As a manufacturing method, a vapor deposition method such as a plasma CVD method or a thermal CVD method, or a sputtering method can be used. Alternatively, a droplet discharge method, a dispenser method, or a printing method (a method for forming a pattern such as screen printing or offset printing) can be used. An SOG film obtained by a coating method can also be used.

First, the case where radiation is performed to the substrate 480 side, that is, the case where downward radiation is performed will be described with reference to FIG. In this case, the wiring layer 498, the first electrode layer 484, the electroluminescent layer 485, and the second electrode layer 486 are sequentially in contact with the source or drain electrode layer 487b so as to be electrically connected to the thin film transistor 481. Laminated. The substrate 480 through which light is transmitted needs to have a light-transmitting property with respect to at least light in the visible region.

Next, the case where radiation is performed on the side opposite to the substrate 460, that is, the case where upward radiation is performed will be described with reference to FIG. The thin film transistor 461 can be formed in a manner similar to that of the thin film transistor 481 described above. A wiring layer 462 which is electrically connected to the thin film transistor 461 is in contact with and electrically connected to the first electrode layer 463. A first electrode layer 463, an electroluminescent layer 464, and a second electrode layer 465 are stacked in this order. The wiring layer 462 is a reflective metal layer and reflects light emitted from the light emitting element to the upper surface of the arrow. Since the wiring layer 462 is stacked with the first electrode layer 463, even if light is transmitted using a light-transmitting material for the first electrode layer 463, the light is transmitted through the wiring layer 462. It is reflected and radiates to the opposite side of the substrate 460. Needless to say, the first electrode layer 463 may be formed using a reflective metal film. Since light emitted from the light-emitting element is emitted through the second electrode layer 465, the second electrode layer 465 is formed using a material that transmits at least light in the visible region.

Finally, a case where light is emitted to the substrate 470 side and the opposite side, that is, a case where both are emitted will be described with reference to FIG. The thin film transistor 471 is also a channel protective thin film transistor. A wiring layer 475 and a first electrode layer 472 are electrically connected to a source electrode layer or a drain electrode layer electrically connected to a semiconductor layer of the thin film transistor 471. A first electrode layer 472, an electroluminescent layer 473, and a second electrode layer 474 are stacked in this order. At this time, when both the first electrode layer 472 and the second electrode layer 474 are formed with a light-transmitting material at least in a visible region or with a thickness capable of transmitting light, both radiations are realized. In this case, the insulating layer through which light is transmitted and the substrate 470 also need to have a light-transmitting property with respect to at least light in the visible region.

This embodiment mode can be freely combined with any of Embodiment Modes 1 to 5.

According to the present invention, a component such as a wiring constituting the display device can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

(Embodiment 7)
In this embodiment, an example of a display device which has high reliability and is manufactured at a low cost through a simplified process will be described. Specifically, a light-emitting display device using a light-emitting element as a display element will be described.

In this embodiment mode, a structure of a light-emitting element that can be used as a display element of the display device of the present invention will be described with reference to FIGS.

FIG. 22 shows an element structure of a light-emitting element, in which an electroluminescent layer 860 formed by mixing an organic compound and an inorganic compound is sandwiched between a first electrode layer 870 and a second electrode layer 850. It is. As illustrated, the electroluminescent layer 860 includes a first layer 804, a second layer 803, and a third layer 802.

First, the first layer 804 is a layer that has a function of transporting holes to the second layer 803, and includes a first organic compound and a first organic electron-accepting property with respect to the first organic compound. It is a structure containing an inorganic compound. What is important is not simply that the first organic compound and the first inorganic compound are mixed, but the first inorganic compound exhibits an electron accepting property with respect to the first organic compound. By adopting such a configuration, many hole carriers are generated in the first organic compound which has essentially no intrinsic carrier, and exhibits extremely excellent hole injection and hole transport properties.

Therefore, the first layer 804 has not only an effect (such as improvement in heat resistance) considered to be obtained by mixing an organic compound and an inorganic compound, but also excellent conductivity (especially in the first layer 804). , Hole injection property and transport property) can also be obtained. This is an effect that cannot be obtained with a conventional hole transport layer in which an organic compound and an inorganic compound that do not have an electronic interaction with each other are simply mixed. Due to this effect, the drive voltage can be made lower than in the prior art. Further, since the first layer 804 can be thickened without causing an increase in driving voltage, a short circuit of an element due to dust or the like can be suppressed.

By the way, as described above, since hole carriers are generated in the first organic compound, the first organic compound is preferably a hole-transporting organic compound. Examples of the hole transporting organic compound include phthalocyanine (abbreviation: H ₂ Pc), copper phthalocyanine (abbreviation: CuPc), vanadyl phthalocyanine (abbreviation: VOPc), 4,4 ′, 4 ″ -tris (N, N -Diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 1,3 , 5-tris [N, N-di (m-tolyl) amino] benzene (abbreviation: m-MTDAB), N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1 ′ -Biphenyl-4,4'-diamine (abbreviation: TPD), 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4,4'-bis {N -[4-di m-tolyl) amino] phenyl-N-phenylamino} biphenyl (abbreviation: DNTPD), 4,4 ′, 4 ″ -tris (N-carbazolyl) triphenylamine (abbreviation: TCTA), and the like. It is not limited to. Among the above-mentioned compounds, aromatic amine compounds represented by TDATA, MTDATA, m-MTDAB, TPD, NPB, DNTPD, TCTA, etc. are likely to generate hole carriers and are suitable as the first organic compound. A group.

On the other hand, the first inorganic compound may be anything as long as it can easily receive electrons from the first organic compound, and various metal oxides or metal nitrides can be used. Any transition metal oxide belonging to Group 12 is preferable because it easily exhibits electron acceptability. Specific examples include titanium oxide, zirconium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide, and zinc oxide. Among the metal oxides described above, any of the transition metal oxides in Groups 4 to 8 of the periodic table has a high electron accepting property and is a preferred group. Vanadium oxide, molybdenum oxide, tungsten oxide, and rhenium oxide are particularly preferable because they can be vacuum-deposited and are easy to handle.

Note that the first layer 804 may be formed by stacking a plurality of layers to which the above-described combination of an organic compound and an inorganic compound is applied. Moreover, other organic compounds or other inorganic compounds may be further contained.

Next, the third layer 802 will be described. The third layer 802 is a layer having a function of transporting electrons to the second layer 803, and includes at least a third organic compound and a third inorganic compound that exhibits an electron donating property with respect to the third organic compound. It is the structure containing these. What is important is not that the third organic compound and the third inorganic compound are merely mixed, but that the third inorganic compound exhibits an electron donating property with respect to the third organic compound. By adopting such a structure, many electron carriers are generated in the third organic compound which has essentially no intrinsic carrier, and exhibits extremely excellent electron injection properties and electron transport properties.

Therefore, the third layer 802 has not only an effect (such as improvement in heat resistance) considered to be obtained by mixing an inorganic compound but also excellent conductivity (especially in the third layer 802, electron injection). And transportability) can also be obtained. This is an effect that cannot be obtained with a conventional electron transport layer in which an organic compound and an inorganic compound that do not have an electronic interaction with each other are simply mixed. Due to this effect, the drive voltage can be made lower than in the prior art. In addition, since the third layer 802 can be thickened without causing an increase in driving voltage, a short circuit of an element due to dust or the like can be suppressed.

By the way, as described above, since an electron carrier is generated in the third organic compound, the third organic compound is preferably an electron-transporting organic compound. Examples of the electron-transporting organic compound include tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [ h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (abbreviation: BAlq), bis [2- (2′-hydroxyphenyl) benzoxa Zolato] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2′-hydroxyphenyl) benzothiazolate] zinc (abbreviation: Zn (BTZ) ₂ ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 2- (4-biphenylyl) -5- (4-tert-butylphenyl)- , 3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (4-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD) -7), 2,2 ′, 2 ″-(1,3,5-benzenetriyl) -tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 3- (4-biphenylyl)- 4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-biphenylyl) -4- (4-ethylphenyl) -5- (4- tert-butylphenyl) -1,2,4-triazole (abbreviation: p-EtTAZ) and the like, but are not limited thereto. Among the compounds described above, a chelate metal complex having a chelate ligand containing an aromatic ring typified by Alq ₃ , Almq ₃ , BeBq ₂ , BAlq, Zn (BOX) ₂ , Zn (BTZ) ₂ , Organic compounds having a phenanthroline skeleton typified by BPhen, BCP, etc., and organic compounds having an oxadiazole skeleton typified by PBD, OXD-7, etc., are likely to generate electron carriers and are suitable as a third organic compound. Compound group.

On the other hand, the third inorganic compound may be anything as long as it easily gives electrons to the third organic compound, and various metal oxides or metal nitrides can be used. Earth metal oxides, rare earth metal oxides, alkali metal nitrides, alkaline earth metal nitrides, and rare earth metal nitrides are preferable because they easily exhibit electron donating properties. Specific examples include lithium oxide, strontium oxide, barium oxide, erbium oxide, lithium nitride, magnesium nitride, calcium nitride, yttrium nitride, and lanthanum nitride. In particular, lithium oxide, barium oxide, lithium nitride, magnesium nitride, and calcium nitride are preferable because they can be vacuum-deposited and are easy to handle.

Note that the third layer 802 may be formed by stacking a plurality of layers to which the above-described combination of an organic compound and an inorganic compound is applied. Moreover, other organic compounds or other inorganic compounds may be further contained.

Next, the second layer 803 will be described. The second layer 803 is a layer having a light emitting function and includes a light emitting second organic compound. Moreover, the structure containing a 2nd inorganic compound may be sufficient. The second layer 803 can be formed using various light-emitting organic compounds and inorganic compounds. However, since the second layer 803 is less likely to flow current than the first layer 804 and the third layer 802, the thickness is preferably about 10 nm to 100 nm.

The second organic compound is not particularly limited as long as it is a luminescent organic compound. For example, 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 9,10-di (2 -Naphthyl) -2-tert-butylanthracene (abbreviation: t-BuDNA), 4,4'-bis (2,2-diphenylvinyl) biphenyl (abbreviation: DPVBi), coumarin 30, coumarin 6, coumarin 545, coumarin 545T , Perylene, rubrene, periflanthene, 2,5,8,11-tetra (tert-butyl) perylene (abbreviation: TBP), 9,10-diphenylanthracene (abbreviation: DPA), 5,12-diphenyltetracene, 4- ( Dicyanomethylene) -2-methyl- [p- (dimethylamino) styryl] -4H-pyran (abbreviation: DCM1), 4- (di Cyanomethylene) -2-methyl-6- [2- (julolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DCM2), 4- (dicyanomethylene) -2,6-bis [p- (dimethylamino) ) Styryl] -4H-pyran (abbreviation: BisDCM) and the like. In addition, bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (picolinate) (abbreviation: FIrpic), bis {2- [3 ′, 5′-bis (trifluoromethyl) ) Phenyl] pyridinato-N, C ^{2 ′} } iridium (picolinate) (abbreviation: Ir (CF ₃ ppy) ₂ (pic)), tris (2-phenylpyridinato-N, C ^{2 ′} ) iridium (abbreviation: Ir (Ppy) ₃ ), bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium (acetylacetonate) (abbreviation: Ir (ppy) ₂ (acac)), bis [2- (2′-thienyl) pyridinato -N, C ^{3 ']} iridium (acetylacetonate) _{(abbreviation: Ir (thp) 2 (acac} )), bis (2-phenylquinolinato--N, C ^2') iridium (Asechirua Tonato) _{(abbreviation: Ir (pq) 2 (acac} )), bis [2- (2'-benzothienyl) pyridinato -N, C ^{3 ']} iridium (acetylacetonate) (abbreviation: Ir _(btp) 2 (acac A compound capable of emitting phosphorescence such as)) can also be used.

For the second layer 803, a triplet excitation material containing a metal complex or the like may be used in addition to the singlet excitation light-emitting material. For example, among red light emitting pixels, green light emitting pixels, and blue light emitting pixels, a red light emitting pixel having a relatively short luminance half time is formed of a triplet excitation light emitting material, and the other A singlet excited luminescent material is used. The triplet excited luminescent material has a feature that the light emission efficiency is good, so that less power is required to obtain the same luminance. That is, when applied to a red light-emitting pixel, the amount of current flowing through the light-emitting element can be reduced, so that reliability can be improved. As a reduction in power consumption, a red light-emitting pixel and a green light-emitting pixel may be formed using a triplet excitation light-emitting material, and a blue light-emitting pixel may be formed using a singlet excitation light-emitting material. By forming a green light-emitting element having high human visibility with a triplet excited light-emitting material, power consumption can be further reduced.

Further, in the second layer 803, not only the second organic compound that emits light but also other organic compounds may be added. Examples of the organic compound that can be added include TDATA, MTDATA, m-MTDAB, TPD, NPB, DNTPD, TCTA, Alq ₃ , Almq ₃ , BeBq ₂ , BAlq, Zn (BOX) ₂ , and Zn (BTZ) described above. ₂ , BPhen, BCP, PBD, OXD-7, TPBI, TAZ, p-EtTAZ, DNA, t-BuDNA, DPVBi, etc., 4,4′-bis (N-carbazolyl) biphenyl (abbreviation: CBP), 1 , 3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB) can be used, but is not limited thereto. In addition, the organic compound added in addition to the second organic compound in this way has an excitation energy larger than the excitation energy of the second organic compound in order to efficiently emit the second organic compound, and the second organic compound. It is preferable to add more than the organic compound (by this, concentration quenching of the second organic compound can be prevented). Or as another function, you may show light emission with a 2nd organic compound (Thereby, white light emission etc. are also attained).

The second layer 803 may have a structure in which a light emitting layer having a different emission wavelength band is formed for each pixel to perform color display. Typically, a light emitting layer corresponding to each color of R (red), G (green), and B (blue) is formed. In this case as well, it is possible to improve color purity and prevent mirror reflection (reflection) of the pixel portion by providing a filter that transmits light in the emission wavelength band on the light emission side of the pixel. Can do. By providing the filter, it is possible to omit a circularly polarizing plate that has been conventionally required, and it is possible to eliminate the loss of light emitted from the light emitting layer. Furthermore, a change in color tone that occurs when the pixel portion (display screen) is viewed obliquely can be reduced.

The material that can be used for the second layer 803 may be a low molecular weight organic light emitting material or a high molecular weight organic light emitting material. The polymer organic light emitting material has higher physical strength and higher device durability than the low molecular weight material. In addition, since the film can be formed by coating, the device can be manufactured relatively easily.

Since the light emission color is determined by the material for forming the light emitting layer, a light emitting element exhibiting desired light emission can be formed by selecting these materials. Examples of the polymer electroluminescent material that can be used for forming the light emitting layer include polyparaphenylene vinylene, polyparaphenylene, polythiophene, and polyfluorene.

Examples of the polyparaphenylene vinylene include poly (paraphenylene vinylene) [PPV] derivatives, poly (2,5-dialkoxy-1,4-phenylene vinylene) [RO-PPV], poly (2- (2′- Ethyl-hexoxy) -5-methoxy-1,4-phenylenevinylene) [MEH-PPV], poly (2- (dialkoxyphenyl) -1,4-phenylenevinylene) [ROPh-PPV] and the like. Examples of polyparaphenylene include derivatives of polyparaphenylene [PPP], poly (2,5-dialkoxy-1,4-phenylene) [RO-PPP], poly (2,5-dihexoxy-1,4-phenylene). ) And the like. The polythiophene series includes polythiophene [PT] derivatives, poly (3-alkylthiophene) [PAT], poly (3-hexylthiophene) [PHT], poly (3-cyclohexylthiophene) [PCHT], poly (3-cyclohexyl). -4-methylthiophene) [PCHMT], poly (3,4-dicyclohexylthiophene) [PDCHT], poly [3- (4-octylphenyl) -thiophene] [POPT], poly [3- (4-octylphenyl) -2,2 bithiophene] [PTOPT] and the like. Examples of the polyfluorene series include polyfluorene [PF] derivatives, poly (9,9-dialkylfluorene) [PDAF], poly (9,9-dioctylfluorene) [PDOF], and the like.

The second inorganic compound may be any inorganic compound as long as it is difficult to quench the light emission of the second organic compound, and various metal oxides and metal nitrides can be used. In particular, a metal oxide of Group 13 or Group 14 of the periodic table is preferable because it is difficult to quench the light emission of the second organic compound, and specifically, aluminum oxide, gallium oxide, silicon oxide, and germanium oxide are preferable. . However, it is not limited to these.

Note that the second layer 803 may be formed by stacking a plurality of layers to which the above-described combination of an organic compound and an inorganic compound is applied. Moreover, other organic compounds or other inorganic compounds may be further contained. The layer structure of the light-emitting layer can be changed, and instead of having a specific electron injection region or light-emitting region, it is possible to provide an electrode layer for electron injection or to have a light-emitting material dispersed. Can be permitted without departing from the spirit of the present invention.

A light-emitting element formed using the above materials emits light by being forward-biased. A pixel of a display device formed using a light-emitting element can be driven by a simple matrix method or an active matrix method. In any case, each pixel emits light by applying a forward bias at a specific timing, but is in a non-light emitting state for a certain period. By applying a reverse bias during this non-light emitting time, the reliability of the light emitting element can be improved. The light emitting element has a degradation mode in which the light emission intensity decreases under a constant driving condition and a degradation mode in which the non-light emitting area is enlarged in the pixel and the luminance is apparently decreased. However, alternating current that applies a bias in the forward and reverse directions. By performing a typical drive, the progress of deterioration can be delayed, and the reliability of the light-emitting display device can be improved. Further, either digital driving or analog driving can be applied.

Therefore, a color filter (colored layer) may be formed on the sealing substrate. The color filter (colored layer) can be formed by an evaporation method or a droplet discharge method. When the color filter (colored layer) is used, high-definition display can be performed. This is because the color filter (colored layer) can be corrected so that a broad peak becomes a sharp peak in the emission spectrum of each RGB.

Full color display can be performed by forming a material exhibiting monochromatic light emission and combining a color filter and a color conversion layer. The color filter (colored layer) and the color conversion layer may be formed on, for example, a sealing substrate and attached to the element substrate.

Of course, monochromatic light emission may be displayed. For example, an area color type display device may be formed using monochromatic light emission. As the area color type, a passive matrix type display unit is suitable, and characters and symbols can be mainly displayed.

The materials of the first electrode layer 870 and the second electrode layer 850 need to be selected in consideration of the work function, and both the first electrode layer 870 and the second electrode layer 850 are anodes depending on the pixel structure. Or a cathode. In the case where the polarity of the driving thin film transistor is a p-channel type, the first electrode layer 870 may be an anode and the second electrode layer 850 may be a cathode as illustrated in FIG. In the case where the polarity of the driving thin film transistor is an n-channel type, it is preferable that the first electrode layer 870 be a cathode and the second electrode layer 850 be an anode as shown in FIG. Materials that can be used for the first electrode layer 870 and the second electrode layer 850 are described. In the case where the first electrode layer 870 and the second electrode layer 850 function as anodes, a material having a high work function (specifically, a material of 4.5 eV or more) is preferable, and the first electrode layer and the second electrode In the case where the layer 850 functions as a cathode, a material having a low work function (specifically, a material having a value of 3.5 eV or less) is preferable. However, since the hole injection and hole transport characteristics of the first layer 804 and the electron injection and electron transport characteristics of the third layer 802 are excellent, both the first electrode layer 870 and the second electrode layer 850 are Various materials can be used with almost no work function limitation.

22A and 22B has a structure in which light is extracted from the first electrode layer 870, the second electrode layer 850 does not necessarily have a light-transmitting property. As the second electrode layer 850, an element selected from Ti, Ni, W, Cr, Pt, Zn, Sn, In, Ta, Al, Cu, Au, Ag, Mg, Ca, Li, or Mo, or nitriding A film mainly composed of an alloy material or a compound material mainly composed of the above elements such as titanium, TiSi _X N _Y , WSi _X , tungsten nitride, WSi _X N _Y , NbN or the like, or a laminated film thereof having a total film thickness of 100 nm to It may be used in the range of 800 nm.

The second electrode layer 850 can be formed by an evaporation method, a sputtering method, a CVD method, a printing method, a dispenser method, a droplet discharge method, or the like.

In addition, when a light-transmitting conductive material such as a material used for the first electrode layer 870 is used for the second electrode layer 850, light is extracted from the second electrode layer 850, so that the light-emitting element can emit light. The emitted light may have a dual emission structure in which both the first electrode layer 870 and the second electrode layer 850 are emitted.

Note that the light-emitting element of the present invention has various variations by changing types of the first electrode layer 870 and the second electrode layer 850.

FIG. 22B illustrates a case where the electroluminescent layer 860 includes the third layer 802, the second layer 803, and the first layer 804 in this order from the first electrode layer 870 side.

As described above, in the light-emitting element of the present invention, the electric field in which the layer sandwiched between the first electrode layer 870 and the second electrode layer 850 includes a layer in which an organic compound and an inorganic compound are combined is included. The light emitting layer 860 is formed. Then, by mixing the organic compound and the inorganic compound, there are provided layers (that is, the first layer 804 and the third layer 802) that can obtain functions of high carrier injection and carrier transport that cannot be obtained independently. This is an organic and inorganic composite light emitting element. In addition, when the first layer 804 and the third layer 802 are provided on the first electrode layer 870 side, the first layer 804 and the third layer 802 need to be a layer in which an organic compound and an inorganic compound are combined. When provided on the 850 side, only an organic compound or an inorganic compound may be used.

Note that although the electroluminescent layer 860 is a layer in which an organic compound and an inorganic compound are mixed, various methods can be used as a formation method thereof. For example, there is a technique in which both an organic compound and an inorganic compound are evaporated by resistance heating and co-evaporated. In addition, while the organic compound is evaporated by resistance heating, the inorganic compound may be evaporated by electron beam (EB) and co-evaporated. Further, there is a method of evaporating the organic compound by resistance heating and simultaneously sputtering the inorganic compound and depositing both at the same time. In addition, the film may be formed by a wet method.

Similarly, for the first electrode layer 870 and the second electrode layer 850, a vapor deposition method using resistance heating, an EB vapor deposition method, a sputtering method, a wet method, or the like can be used. As shown in Embodiment Mode 3, the first electrode layer 870 and the second electrode layer 850 are selectively formed by irradiating with a laser beam after forming a conductive light absorption film on the transfer substrate. The transfer substrate may be processed into a desired shape.

FIG. 22C illustrates a structure in which a reflective electrode layer is used for the first electrode layer 870 and a light-transmitting electrode layer is used for the second electrode layer 850 in FIG. Light emitted from the element is reflected by the first electrode layer 870 and transmitted through the second electrode layer 850 to be emitted. Similarly, in FIG. 22D, a reflective electrode layer is used for the first electrode layer 870 and a light-transmitting electrode layer is used for the second electrode layer 850 in FIG. 22B. The light emitted from the light emitting element is reflected by the first electrode layer 870 and is transmitted through the second electrode layer 850 and emitted.

This embodiment mode can be freely combined with the embodiment mode of the display device having the above light-emitting element. This embodiment mode can be freely combined with each of Embodiment Modes 1 to 5 as appropriate.

According to the present invention, a component such as a wiring constituting a display device or the like can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

(Embodiment 8)
In this embodiment, an example of a display device which has high reliability and is manufactured at a low cost through a simplified process will be described. Specifically, a light-emitting display device using a light-emitting element as a display element will be described. In this embodiment mode, structures of light-emitting elements that can be used as display elements of the display device of the present invention will be described with reference to FIGS.

A light-emitting element utilizing electroluminescence is distinguished depending on whether the light-emitting material is an organic compound or an inorganic compound. Generally, the former is called an organic EL element and the latter is called an inorganic EL element.

Inorganic EL elements are classified into a dispersion-type inorganic EL element and a thin-film inorganic EL element depending on the element structure. The former has an electroluminescent layer in which particles of a luminescent material are dispersed in a binder, and the latter has an electroluminescent layer made of a thin film of luminescent material, but is accelerated by a high electric field. This is common in that it requires more electrons. Note that the obtained light emission mechanism includes donor-acceptor recombination light emission using a donor level and an acceptor level, and localized light emission using inner-shell electron transition of a metal ion. In general, the dispersion-type inorganic EL often has donor-acceptor recombination light emission, and the thin-film inorganic EL element often has localized light emission.

A light-emitting material that can be used in the present invention includes a base material and an impurity element serving as a light emission center. By changing the impurity element to be contained, light emission of various colors can be obtained. As a method for manufacturing the light-emitting material, various methods such as a solid phase method and a liquid phase method (coprecipitation method) can be used. Also, spray pyrolysis method, metathesis method, precursor thermal decomposition method, reverse micelle method, method combining these methods with high temperature firing, liquid phase method such as freeze-drying method, etc. can be used.

The solid phase method is a method in which a base material and an impurity element or a compound containing the impurity element are weighed, mixed in a mortar, heated and fired in an electric furnace, reacted, and the base material contains the impurity element. The firing temperature is preferably 700 to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state. Although firing at a relatively high temperature is required, it is a simple method, so it has high productivity and is suitable for mass production.

The liquid phase method (coprecipitation method) is a method in which a base material or a compound containing the base material and an impurity element or a compound containing the impurity element are reacted in a solution, dried, and then fired. The particles of the luminescent material are uniformly distributed, and the reaction can proceed even at a low firing temperature with a small particle size.

As a base material used for the light-emitting material, sulfide, oxide, or nitride can be used. Examples of the sulfide include zinc sulfide (ZnS), cadmium sulfide (CdS), calcium sulfide (CaS), yttrium sulfide (Y ₂ S ₃ ), gallium sulfide (Ga ₂ S ₃ ), strontium sulfide (SrS), sulfide. Barium (BaS) or the like can be used. As the oxide, for example, zinc oxide (ZnO), yttrium oxide (Y ₂ O ₃ ), or the like can be used. As the nitride, for example, aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN), or the like can be used. Furthermore, zinc selenide (ZnSe), zinc telluride (ZnTe), and the like can also be used, and calcium sulfide-gallium sulfide (CaGa ₂ S ₄ ), strontium sulfide-gallium sulfide (SrGa ₂ S ₄ ), barium sulfide-gallium (BaGa). _It may be a ternary mixed crystal such as ₂ S ₄ ).

As emission centers of localized emission, manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), thulium (Tm), europium (Eu), cerium (Ce), praseodymium (Pr) or the like can be used. Note that a halogen element such as fluorine (F) or chlorine (Cl) may be added. The halogen element can also function as charge compensation.

On the other hand, a light-emitting material containing a first impurity element that forms a donor level and a second impurity element that forms an acceptor level can be used as the emission center of donor-acceptor recombination light emission. As the first impurity element, for example, fluorine (F), chlorine (Cl), aluminum (Al), or the like can be used. For example, copper (Cu), silver (Ag), or the like can be used as the second impurity element.

In the case where a light-emitting material for donor-acceptor recombination light emission is synthesized using a solid-phase method, a base material, a first impurity element or a compound containing the first impurity element, a second impurity element, or a second impurity element Each compound containing an impurity element is weighed and mixed in a mortar, and then heated and fired in an electric furnace. As the base material, the above-described base material can be used, and examples of the first impurity element or the compound containing the first impurity element include fluorine (F), chlorine (Cl), and aluminum sulfide (Al ₂ S). ₃ ) or the like, and examples of the second impurity element or the compound containing the second impurity element include copper (Cu), silver (Ag), copper sulfide (Cu ₂ S), and silver sulfide (Ag). ₂ S) or the like can be used. The firing temperature is preferably 700 to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state.

In addition, as an impurity element in the case of using a solid phase reaction, a compound including a first impurity element and a second impurity element may be used in combination. In this case, since the impurity element is easily diffused and the solid-phase reaction easily proceeds, a uniform light emitting material can be obtained. Further, since no extra impurity element is contained, a light-emitting material with high purity can be obtained. As the compound including the first impurity element and the second impurity element, for example, copper chloride (CuCl), silver chloride (AgCl), or the like can be used.

Note that the concentration of these impurity elements may be 0.01 to 10 atom% with respect to the base material, and is preferably in the range of 0.05 to 5 atom%.

In the case of a thin-film inorganic EL, the electroluminescent layer is a layer containing the above-described luminescent material, and is a physical vapor deposition method such as a resistance heating vapor deposition method, a vacuum vapor deposition method such as an electron beam vapor deposition (EB vapor deposition) method, or a sputtering method ( PVD), metal organic chemical vapor deposition (CVD), chemical vapor deposition (CVD) such as hydride transport low pressure CVD, atomic layer epitaxy (ALE), or the like.

FIGS. 23A to 23C illustrate an example of a thin-film inorganic EL element that can be used as a light-emitting element. 23A to 23C, the light-emitting element includes a first electrode layer 50, an electroluminescent layer 52, and a second electrode layer 53.

The light-emitting element illustrated in FIGS. 23B and 23C has a structure in which an insulating layer is provided between the electrode layer and the electroluminescent layer in the light-emitting element in FIG. The light-emitting element illustrated in FIG. 23B includes an insulating layer 54 between the first electrode layer 50 and the electroluminescent layer 52, and the light-emitting element illustrated in FIG. 23C includes the first electrode layer 50. And an electroluminescent layer 52, and an insulating layer 54 b is provided between the second electrode layer 53 and the electroluminescent layer 52. Thus, the insulating layer may be provided only between one of the pair of electrode layers sandwiching the electroluminescent layer, or may be provided between both. Further, the insulating layer may be a single layer or a stacked layer including a plurality of layers.

23B, the insulating layer 54 is provided so as to be in contact with the first electrode layer 50. However, the order of the insulating layer and the electroluminescent layer is reversed so as to be in contact with the second electrode layer 53. An insulating layer 54 may be provided.

In the case of a dispersion-type inorganic EL element, a particulate light emitting material is dispersed in a binder to form a film-like electroluminescent layer. When particles having a desired size cannot be obtained sufficiently by the method for manufacturing a light emitting material, the particles may be processed into particles by pulverization or the like in a mortar or the like. A binder is a substance for fixing a granular light emitting material in a dispersed state and maintaining the shape as an electroluminescent layer. The light emitting material is uniformly dispersed and fixed in the electroluminescent layer by the binder.

In the case of a dispersion-type inorganic EL element, the electroluminescent layer can be formed by a droplet discharge method capable of selectively forming an electroluminescent layer, a printing method (screen printing, offset printing, etc.), a coating method such as a spin coating method, A dipping method, a dispenser method, or the like can also be used. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm. In the electroluminescent layer including the light emitting material and the binder, the ratio of the light emitting material may be 50 wt% or more and 80 wt% or less.

24A to 24C illustrate an example of a dispersion-type inorganic EL element that can be used as a light-emitting element. A light-emitting element in FIG. 24A has a stacked structure of a first electrode layer 60, an electroluminescent layer 62, and a second electrode layer 63, and a luminescent material 61 held by a binder in the electroluminescent layer 62. Including.

Further, as shown in Embodiment Mode 3, the first electrode layers 50 and 60 and the second electrode layers 53 and 63 are also irradiated with laser light after a conductive light absorption film is formed on the transfer substrate. Alternatively, the transfer substrate may be selectively processed into a desired shape.

As a binder that can be used in this embodiment mode, an organic material or an inorganic material can be used, and a mixed material of an organic material and an inorganic material may be used. As the organic material, a polymer having a relatively high dielectric constant such as a cyanoethyl cellulose resin, or a resin such as polyethylene, polypropylene, polystyrene resin, silicone resin, epoxy resin, or vinylidene fluoride can be used. Alternatively, a heat-resistant polymer such as aromatic polyamide, polybenzimidazole, or siloxane resin may be used. Note that a siloxane resin corresponds to a resin including a Si—O—Si bond. Siloxane has a skeleton structure formed of a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aromatic hydrocarbon) is used. A fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as a substituent. Moreover, resin materials such as vinyl resins such as polyvinyl alcohol and polyvinyl butyral, phenol resins, novolac resins, acrylic resins, melamine resins, urethane resins, and oxazole resins (polybenzoxazole) may be used. The dielectric constant can be adjusted by appropriately mixing fine particles of high dielectric constant such as barium titanate (BaTiO ₃ ) and strontium titanate (SrTiO ₃ ) with these resins.

Examples of the inorganic material contained in the binder include silicon oxide (SiOx), silicon nitride (SiNx), silicon containing oxygen and nitrogen, aluminum nitride (AlN), aluminum containing oxygen and nitrogen or aluminum oxide (Al ₂ O ₃ ), Titanium oxide (TiO ₂ ), BaTiO ₃ , SrTiO ₃ , lead titanate (PbTiO ₃ ), potassium niobate (KNbO ₃ ), lead niobate (PbNbO ₃ ), tantalum oxide (Ta ₂ O ₅ ), barium tantalate ( BaTa ₂ O ₆ ), lithium tantalate (LiTaO ₃ ), yttrium oxide (Y ₂ O ₃ ), zirconium oxide (ZrO ₂ ), and other materials including inorganic insulating materials can be used. . By including an inorganic material having a high dielectric constant in the organic material (by addition or the like), the dielectric constant of the electroluminescent layer made of the light emitting material and the binder can be further controlled, and the dielectric constant can be further increased. . When a mixed layer of an inorganic material and an organic material is used for the binder and the dielectric constant is high, a larger charge can be induced in the light emitting material.

In the manufacturing process, the light-emitting material is dispersed in a solution containing a binder, but as a solvent for the solution containing the binder that can be used in this embodiment, a method of forming an electroluminescent layer by dissolving the binder material (various types) The wet process) and a solvent capable of producing a solution having a viscosity suitable for a desired film thickness may be selected as appropriate. For example, when a siloxane resin is used as a binder, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate (also referred to as PGMEA), 3-methoxy-3-methyl-1-butanol (also referred to as MMB) can be used. Etc. can be used.

The light-emitting element illustrated in FIGS. 24B and 24C has a structure in which an insulating layer is provided between the electrode layer and the electroluminescent layer in the light-emitting element in FIG. The light-emitting element illustrated in FIG. 24B includes an insulating layer 64 between the first electrode layer 60 and the electroluminescent layer 62, and the light-emitting element illustrated in FIG. 24C includes the first electrode layer 60. And an electroluminescent layer 62, and an insulating layer 64 b between the second electrode layer 63 and the electroluminescent layer 62. Thus, the insulating layer may be provided only between one of the pair of electrode layers sandwiching the electroluminescent layer, or may be provided between both. Further, the insulating layer may be a single layer or a stacked layer including a plurality of layers.

In FIG. 24B, the insulating layer 64 is provided so as to be in contact with the first electrode layer 60; however, the order of the insulating layer and the electroluminescent layer is reversed so as to be in contact with the second electrode layer 63. An insulating layer 64 may be provided on the substrate.

Insulating layers such as the insulating layer 54 in FIG. 23 and the insulating layer 64 in FIG. 24 are not particularly limited, but preferably have a high withstand voltage, a dense film quality, and a high dielectric constant. It is preferable. For example, silicon oxide (SiO ₂ ), yttrium oxide (Y ₂ O ₃ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), tantalum oxide (Ta ₂ O ₅ ), Barium titanate (BaTiO ₃ ), strontium titanate (SrTiO ₃ ), lead titanate (PbTiO ₃ ), silicon nitride (Si ₃ N ₄ ), zirconium oxide (ZrO ₂ ), etc., a mixed film thereof, or two or more kinds thereof A laminated film can be used. These insulating films can be formed by sputtering, vapor deposition, CVD, or the like. The insulating layer may be formed by dispersing particles of these insulating materials in a binder. The binder material may be formed using the same material and method as the binder contained in the electroluminescent layer. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm.

The light-emitting element described in this embodiment can emit light by applying a voltage between a pair of electrode layers sandwiching an electroluminescent layer, but can operate in either direct current drive or alternating current drive.

According to the present invention, a component such as a wiring constituting a display device or the like can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

This embodiment mode can be freely combined with each of Embodiment Modes 1 to 5 as appropriate.

(Embodiment 9)
In this embodiment, an example of a display device which has high reliability and is manufactured at a low cost through a simplified process will be described. Specifically, a liquid crystal display device using a liquid crystal display element as a display element will be described.

19A is a top view of the liquid crystal display device, and FIG. 19B is a cross-sectional view taken along line GH in FIG. 19A.

As shown in FIG. 19A, a pixel region 606, a driver circuit region 608a which is a scan line driver circuit, and a driver circuit region 608b are sealed between a substrate 600 and a counter substrate 695 by a sealant 692. A driving circuit region 607 which is a signal line driving circuit formed by an IC driver is provided over the substrate 600. A transistor 622 and a capacitor 623 are provided in the pixel region 606, and a driver circuit including a transistor 620 and a transistor 621 is provided in the driver circuit region 608b. For the substrate 600, an insulating substrate similar to that in the above embodiment can be used. In general, substrates made of synthetic resin have a concern that the heat-resistant temperature is lower than other substrates, but they can also be adopted by transposing after a manufacturing process using a substrate with high heat resistance. Is possible.

In the pixel region 606, a transistor 622 serving as a switching element is provided through a base film 604a and a base film 604b. In this embodiment, a multi-gate thin film transistor (TFT) is used for the transistor 622, a semiconductor layer having an impurity region functioning as a source region and a drain region, a gate insulating layer, a gate electrode layer having a two-layer structure, a source An electrode layer and a drain electrode layer are included, and the source electrode layer or the drain electrode layer is in contact with and electrically connected to the impurity region of the semiconductor layer and the pixel electrode layer 630.

The source and drain electrode layers have a stacked structure, and the source or drain electrode layers 644 a and 644 b are electrically connected to the pixel electrode layer 630 through openings formed in the insulating layer 615. The opening formed in the insulating layer 615 can be formed by irradiation with laser light as described in Embodiment Mode 2. In this embodiment, a low-melting point metal (chromium in this embodiment) that is relatively easily evaporated is used for the source electrode layer or the drain electrode layer 644b, and the source electrode layer or the drain electrode is used for the source electrode layer or the drain electrode layer 644a. A refractory metal (tungsten in this embodiment) that is harder to evaporate than the layer 644b is used. The source electrode or drain electrode layers 644a and 644b are selectively irradiated with laser light from the insulating layer 615 side, and the insulating layer 615 on the irradiation region of the source electrode layer or drain electrode layer 644b is removed by the irradiated energy. An opening can be formed. The pixel electrode layer 630 is formed in the opening from which the source or drain electrode layers 644a and 644b are exposed, and the source or drain electrode layers 644a and 644b and the pixel electrode layer 630 can be electrically connected.

Thin film transistors can be manufactured by a number of methods. For example, a crystalline semiconductor film is applied as the active layer. A gate electrode is provided over the crystalline semiconductor film with a gate insulating film interposed therebetween. An impurity element can be added to the active layer using the gate electrode. Thus, it is not necessary to form a mask for adding the impurity element by adding the impurity element using the gate electrode. The gate electrode can have a single-layer structure or a stacked structure. The impurity region can be a high concentration impurity region and a low concentration impurity region by controlling the concentration thereof. A thin film transistor having such a low concentration impurity region is referred to as an LDD (Lightly Doped Drain) structure. The low-concentration impurity region can be formed so as to overlap with the gate electrode. Such a thin film transistor is referred to as a GOLD (Gate Overlapped LDD) structure. The polarity of the thin film transistor is n-type by using phosphorus (P) or the like in the impurity region. When p-type is used, boron (B) or the like may be added. After that, an insulating film 611 and an insulating film 612 that cover the gate electrode and the like are formed. A dangling bond in the crystalline semiconductor film can be terminated by a hydrogen element mixed in the insulating film 611 (and the insulating film 612).

In order to further improve the flatness, an insulating layer 615 may be formed as an interlayer insulating layer. For the insulating layer 615, an organic material, an inorganic material, or a stacked structure thereof can be used. For example, silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, aluminum nitride, aluminum oxynitride, aluminum nitride oxide or aluminum oxide whose nitrogen content is higher than oxygen content, diamond like carbon (DLC), polysilazane, nitrogen content It can be formed of a material selected from carbon (CN), PSG (phosphorus glass), BPSG (phosphorus boron glass), alumina, and other inorganic insulating materials. An organic insulating material may be used, and the organic material may be either photosensitive or non-photosensitive, and polyimide, acrylic, polyamide, polyimide amide, resist, benzocyclobutene, siloxane resin, or the like can be used. . Note that a siloxane resin corresponds to a resin including a Si—O—Si bond. Siloxane has a skeleton structure formed of a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aromatic hydrocarbon) is used. A fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as a substituent.

In addition, by using a crystalline semiconductor film, the pixel region and the driver circuit region can be formed over the same substrate. In that case, the transistor in the pixel portion and the transistor in the driver circuit region 608b are formed at the same time. Transistors used for the driver circuit region 608b constitute a CMOS circuit. Although the thin film transistor included in the CMOS circuit has a GOLD structure, an LDD structure such as the transistor 622 can also be used.

Without being limited to this embodiment mode, the thin film transistor in the pixel region may have a single gate structure in which one channel formation region is formed, a double gate structure in which two channel formation regions are formed, or a triple gate structure in which three channel formation regions are formed. . The thin film transistor in the peripheral driver circuit region may have a single gate structure, a double gate structure, or a triple gate structure.

Note that the present invention is not limited to the thin film transistor described in this embodiment mode, and is a top gate type (eg, forward stagger type), bottom gate type (eg, inverted stagger type), or gate insulating films above and below a channel region. The present invention can also be applied to a dual gate type or other structure having two gate electrode layers arranged in a row.

Next, an insulating layer 631 called an alignment film is formed by a printing method or a droplet discharge method so as to cover the pixel electrode layer 630. Note that the insulating layer 631 can be selectively formed by a screen printing method or an offset printing method. Thereafter, a rubbing process is performed. This rubbing process may not be performed in the liquid crystal mode, for example, the VA mode. The insulating layer 633 functioning as an alignment film is similar to the insulating layer 631. Subsequently, a sealant 692 is formed in a peripheral region where pixels are formed by a droplet discharge method.

After that, a counter substrate 695 provided with an insulating layer 633 functioning as an alignment film, a conductive layer 634 functioning as a counter electrode, a colored layer 635 functioning as a color filter, and a polarizer 641 (also referred to as a polarizing plate), and a TFT substrate The substrate 600 is bonded through a spacer 637, and a liquid crystal layer 632 is provided in the gap. Since the liquid crystal display device in this embodiment is a transmissive type, a polarizer (polarizing plate) 643 is provided on the side opposite to the surface of the substrate 600 having elements. The polarizer can be provided on the substrate by an adhesive layer. A filler may be mixed in the sealing material, and a shielding film (black matrix) or the like may be formed on the counter substrate 695. Note that the color filter or the like may be formed from a material exhibiting red (R), green (G), and blue (B) when the liquid crystal display device is set to full color display. It may be formed of a material that eliminates or exhibits at least one color.

Note that a color filter may not be provided when an RGB light emitting diode (LED) or the like is arranged in the backlight and a continuous additive color mixing method (field sequential method) in which color display is performed by time division is adopted. The black matrix is preferably provided so as to overlap with the transistor or the CMOS circuit in order to reduce reflection of external light due to the wiring of the transistor or the CMOS circuit. Note that the black matrix may be formed so as to overlap with the capacitor. This is because reflection by the metal film constituting the capacitor element can be prevented.

As a method for forming the liquid crystal layer, a dispenser method (a dropping method) or an injection method in which liquid crystal is injected using a capillary phenomenon after the substrate 600 having an element and the counter substrate 695 are bonded to each other can be used. The dropping method is preferably applied when handling a large substrate to which the injection method is difficult to apply.

The spacer may be provided by spraying particles of several μm, but in this embodiment, a method of forming a resin film on the entire surface of the substrate and then etching it is employed. After applying such a spacer material with a spinner, it is formed into a predetermined pattern by exposure and development processing. Further, it is cured by heating at 150 to 200 ° C. in a clean oven or the like. The spacers produced in this way can have different shapes depending on the conditions of exposure and development processing, but preferably, the spacers are columnar and the top is flat, so that the opposite substrate is When combined, the mechanical strength of the liquid crystal display device can be ensured. The shape can be a conical shape, a pyramid shape or the like, and there is no particular limitation.

Subsequently, an FPC 694 which is a wiring board for connection is provided on the terminal electrode layers 678a and 678b electrically connected to the pixel region with an anisotropic conductive layer 696 interposed therebetween. The FPC 694 plays a role of transmitting an external signal or potential. Through the above steps, a liquid crystal display device having a display function can be manufactured.

Note that a wiring included in the transistor, a gate electrode layer, a pixel electrode layer 630, and a conductive layer 634 which is a counter electrode layer include indium tin oxide (ITO), indium oxide and zinc oxide (ZnO) mixed in IZO (indium zinc oxide). Indium oxide mixed with silicon oxide (SiO ₂ ), indium oxide, organic tin, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, titanium oxide Indium tin oxide containing, tungsten (W), molybdenum (Mo), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), cobalt (Co) Nickel (Ni), Titanium (Ti), Platinum (Pt), Aluminum It can be selected from metals such as luminium (Al), copper (Cu), silver (Ag), alloys thereof, or metal nitrides thereof.

You may laminate | stack in the state which had the phase difference plate between the polarizing plate and the liquid-crystal layer.

Note that although a TN liquid crystal panel is described in this embodiment mode, the above process can be similarly applied to other types of liquid crystal panels. For example, the present embodiment can be applied to a horizontal electric field type liquid crystal panel in which an electric field is applied in parallel with a glass substrate to align liquid crystals. Further, the present embodiment can be applied to a VA (Vertical Alignment) liquid crystal panel.

5 and 6 show the pixel structure of the VA liquid crystal panel. FIG. 5 is a plan view, and FIG. 6 shows a cross-sectional structure corresponding to the cutting line I-J shown in the drawing. The following description will be given with reference to both the drawings.

In this pixel structure, a single pixel has a plurality of pixel electrodes, and a TFT is connected to each pixel electrode. Each TFT is configured to be driven by a different gate signal. In other words, a multi-domain designed pixel has a configuration in which signals applied to individual pixel electrodes are controlled independently.

The pixel electrode layer 1624 is connected to the TFT 1628 through a wiring layer 1618 through an opening (contact hole) 1623. The pixel electrode layer 1626 is connected to the TFT 1629 through an opening (contact hole) 1627 through a wiring layer 1619. The gate wiring layer 1602 of the TFT 1628 and the gate electrode layer 1603 of the TFT 1629 are separated so that different gate signals can be given. On the other hand, the wiring layer 1616 functioning as a data line is used in common by the TFT 1628 and the TFT 1629.

As shown in Embodiment Mode 3, the pixel electrode layer 1624 and the pixel electrode layer 1626 are selectively formed on the transfer substrate by forming a light-absorbing film having conductivity on the transfer substrate and then irradiating with a laser beam. It may be formed by processing into the shape. In this manner, when the present invention is used, the process can be simplified and material loss can be prevented; thus, a display device can be manufactured at low cost with high productivity.

The pixel electrode layer 1624 and the pixel electrode layer 1626 have different shapes and are separated by a slit 1625. A pixel electrode layer 1626 is formed so as to surround the outside of the V-shaped pixel electrode layer 1624. The timing of the voltage applied to the pixel electrode layer 1624 and the pixel electrode layer 1626 is varied depending on the TFT 1628 and the TFT 1629, thereby controlling the alignment of the liquid crystal. A counter substrate 1601 is provided with a light-blocking film 1632, a coloring layer 1636, and a counter electrode layer 1640. In addition, a planarization film 1637 is formed between the coloring layer 1636 and the counter electrode layer 1640 to prevent alignment disorder of the liquid crystal. FIG. 7 shows a structure on the counter substrate side. The counter electrode layer 1640 is a common electrode between different pixels, but a slit 1641 is formed. By arranging the slits 1641 and the slits 1625 on the pixel electrode layer 1624 and pixel electrode layer 1626 side to alternately engage with each other, an oblique electric field can be effectively generated to control the alignment of the liquid crystal. Thereby, the direction in which the liquid crystal is aligned can be varied depending on the location, and the viewing angle is widened.

Thus, a liquid crystal panel can be manufactured using a composite material in which an organic compound and an inorganic compound are combined as the pixel electrode layer. By using such a pixel electrode layer, it is not necessary to use a transparent conductive film containing indium as a main component, and a bottleneck in terms of raw materials can be eliminated.

This embodiment mode can be freely combined with any of Embodiment Modes 1 to 3 as appropriate.

According to the present invention, a component such as a wiring constituting the display device can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

(Embodiment 10)
In this embodiment, an example of a display device which has high reliability and is manufactured at a low cost through a simplified process will be described. Specifically, a liquid crystal display device using a liquid crystal display element as a display element will be described.

In the display device illustrated in FIG. 18, a transistor 220 which is an inverted staggered thin film transistor, a pixel electrode layer 251, an insulating layer 252, an insulating layer 253, a liquid crystal layer 254, a spacer 281, an insulating layer 235, and a counter region are formed over a substrate 250. Electrode layer 256, color filter 258, black matrix 257, counter substrate 210, polarizing plate (polarizer) 231, polarizing plate (polarizer) 233, sealing material 282 in sealing region, terminal electrode layer 287, anisotropic conductive layer 288 and FPC 286 are provided.

As shown in Embodiment Mode 3, the gate electrode layer, the semiconductor layer, the source electrode layer, the drain electrode layer, and the pixel electrode layer 251 of the transistor 220 that is an inverted staggered thin film transistor manufactured in this embodiment mode are formed over the transfer substrate. After the light absorption film using a conductive material or a semiconductor material is formed, it may be formed by selectively processing the transferred substrate into a desired shape by irradiation with laser light. In this manner, when the present invention is used, the process can be simplified and material loss can be prevented; thus, a display device can be manufactured at low cost with high productivity.

In this embodiment mode, an amorphous semiconductor is used as a semiconductor layer, and a semiconductor layer having one conductivity type may be formed as needed. In this embodiment mode, an amorphous n-type semiconductor layer is stacked as a semiconductor layer and a semiconductor layer having one conductivity type. In addition, an n-type semiconductor layer is formed, an NMOS structure of an n-channel thin film transistor, a PMOS structure of a p-channel thin film transistor in which a p-type semiconductor layer is formed, and a CMOS structure of an n-channel thin film transistor and a p-channel thin film transistor. it can.

In order to impart conductivity, an element imparting conductivity is added by doping, and an impurity region is formed in the semiconductor layer, whereby an n-channel thin film transistor or a P-channel thin film transistor can be formed. Instead of forming the n-type semiconductor layer, conductivity may be imparted to the semiconductor layer by performing plasma treatment with PH ₃ gas.

In this embodiment, the transistor 220 is an n-channel inverted staggered thin film transistor. Alternatively, a channel-protective inverted staggered thin film transistor in which a protective layer is provided over the channel region of the semiconductor layer can be used.

Next, the configuration of the backlight unit 352 will be described. The backlight unit 352 includes a cold cathode tube, a hot cathode tube, a light emitting diode, an inorganic EL, and an organic EL as a light source 361 that emits fluorescence, a lamp reflector 362 for efficiently guiding the fluorescence to the light guide plate 365, and the fluorescence is totally reflected. However, a light guide plate 365 for guiding light to the entire surface, a diffusion plate 366 for reducing unevenness in brightness, and a reflection plate 364 for reusing light leaked under the light guide plate 365 are provided. .

A control circuit for adjusting the luminance of the light source 361 is connected to the backlight unit 352. The luminance of the light source 361 can be controlled by supplying a signal from the control circuit.

A source electrode layer or a drain electrode layer of the transistor 220 is electrically connected to the pixel electrode layer 251 through an opening formed in the insulating layer 252. The opening formed in the insulating layer 252 can be formed by irradiation with laser light as described in Embodiment Mode 1. In this embodiment, a low-melting-point metal (chromium in this embodiment) that is relatively easily evaporated is used for the source electrode layer or the drain electrode layer. The source electrode layer or the drain electrode layer is selectively irradiated with laser light from the insulating layer 252 side, and the insulating layer 252 on the irradiation region of the source electrode layer or the drain electrode layer is removed by the irradiated energy to form an opening. be able to. The pixel electrode layer 251 can be formed in the opening from which the source or drain electrode layer is exposed, and the source or drain electrode layer and the pixel electrode layer 251 can be electrically connected.

This embodiment mode can be combined with any of Embodiment Modes 1 to 3 as appropriate.

According to the present invention, a component such as a wiring constituting the display device can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

(Embodiment 11)
In this embodiment, an example of a display device which has high reliability and is manufactured at a low cost through a simplified process will be described.

FIG. 21 shows active matrix electronic paper to which the present invention is applied. Although an active matrix type is shown in FIG. 21, the present invention can also be applied to a passive matrix type.

A twist ball display system can be used as the electronic paper. In the twist ball display system, spherical particles that are separately painted in white and black are arranged between the first electrode layer and the second electrode layer, and a potential difference is generated between the first electrode layer and the second electrode layer. In this method, display is performed by controlling the orientation of the spherical particles.

The transistor 581 is a reverse coplanar thin film transistor and includes a gate electrode layer 582, a gate insulating layer 584, a wiring layer 585 a, a wiring layer 585 b, and a semiconductor layer 586. The wiring layer 585b is in contact with and electrically connected to the first electrode layer 587a through an opening formed in the insulating layer 598. Between the first electrode layers 587a and 587b and the second electrode layer 588, spherical particles 589 including a cavity 594 having a black region 590a and a white region 590b and filled with a liquid are provided. The periphery of the spherical particles 589 is filled with a filler 595 such as resin (see FIG. 21).

In this embodiment mode, as shown in Embodiment Mode 3, the gate electrode layer, the semiconductor layer, the source electrode layer, the drain electrode layer, the electrode layer, and the like are subjected to laser light after forming a conductive light absorption film over the transfer substrate. May be formed by selectively processing the transferred substrate into a desired shape. When the present invention is used, the process can be simplified and material loss can be prevented, so that cost reduction can be achieved.

The wiring layer 585b is electrically connected to the first electrode layer 587a through an opening formed in the insulating layer 598. An opening formed in the insulating layer 598 can be formed by irradiation with laser light as described in Embodiment Mode 1. In this embodiment mode, a low melting point metal (chromium in this embodiment mode) that is relatively easily evaporated is used for the wiring layer 585b. The wiring layer 585b is selectively irradiated with laser light from the insulating layer 598 side, and the insulating layer 598 over the irradiation region of the wiring layer 585b is removed by the irradiated energy, so that an opening can be formed. A first electrode layer 587a is formed in the opening from which the wiring layer 585b is exposed, and the wiring layer 585b and the first electrode layer 587a can be electrically connected.

Further, instead of the twisting ball, an electrophoretic element can be used. A microcapsule having a diameter of about 10 μm to 200 μm in which transparent liquid, positively charged white microparticles, and negatively charged black microparticles are enclosed is used. In the microcapsule provided between the first electrode layer and the second electrode layer, when an electric field is applied by the first electrode layer and the second electrode layer, the white particles and the black particles are in opposite directions. And can display white or black. A display element using this principle is an electrophoretic display element, and is generally called electronic paper. Since the electrophoretic display element has higher reflectance than the liquid crystal display element, an auxiliary light is unnecessary, power consumption is small, and the display portion can be recognized even in a dim place. In addition, even when power is not supplied to the display unit, it is possible to retain the image once displayed. Therefore, even when the display device with a display function is moved away from the radio wave source, it is displayed. The image can be stored.

The transistor may have any structure as long as it can function as a switching element. As the semiconductor layer, various semiconductors such as an amorphous semiconductor, a crystalline semiconductor, a polycrystalline semiconductor, and a microcrystalline semiconductor can be used, and an organic transistor may be formed using an organic compound.

In this embodiment mode, specifically, the case where the structure of the display device is an active matrix type is shown; however, the present invention can also be applied to a passive matrix type display device. Even in a passive matrix display device, a wiring layer, an electrode layer, and the like are selectively processed into a desired shape on a transferred substrate by irradiating with a laser beam after forming a conductive light absorption film on the transferred substrate. May be formed.

This embodiment mode can be freely combined with any of Embodiment Modes 1 to 3 as appropriate.

According to the present invention, a component such as a wiring constituting the display device can be formed in a desired shape. In addition, a display device can be manufactured through a simplified process by reducing complicated photolithography processes, so that material loss is small and cost reduction can be achieved. Therefore, a high-performance and highly reliable display device can be manufactured with high yield.

(Embodiment 12)
Next, a mode in which a driver circuit for driving is mounted on the display panel manufactured according to Embodiment Modes 4 to 11 will be described.

First, a display device employing a COG method is described with reference to FIG. A pixel portion 2701 for displaying information such as characters and images is provided over the substrate 2700. A substrate provided with a plurality of drive circuits is divided into a rectangular shape, and a divided drive circuit (also referred to as a driver IC) 2751 is mounted on the substrate 2700. FIG. 26A illustrates a mode in which an FPC 2750 is mounted on the tip of a plurality of driver ICs 2751 and driver ICs 2751. Further, the size of dividing the driver IC may be almost the same as the length of the side of the pixel portion on the signal line side, and a tape may be mounted on the tip of the driver IC on a single driver IC.

Alternatively, a TAB method may be employed. In that case, a plurality of tapes may be attached and driver ICs may be mounted on the tapes as shown in FIG. As in the case of the COG method, a single driver IC may be mounted on a single tape. In this case, a metal piece or the like for fixing the driver IC may be attached together due to strength problems.

A plurality of driver ICs mounted on these display panels may be formed on a rectangular substrate having a side of 300 mm to 1000 mm or more from the viewpoint of improving productivity.

That is, a plurality of circuit patterns having a drive circuit portion and an input / output terminal as one unit may be formed on the substrate, and finally divided and taken out. The long side of the driver IC may be formed in a rectangular shape having a long side of 15 to 80 mm and a short side of 1 to 6 mm in consideration of the length of one side of the pixel portion and the pixel pitch. Or a length obtained by adding one side of the pixel portion and one side of each driver circuit.

The advantage of the external dimensions of the driver IC over the IC chip lies in the length of the long side. When a driver IC formed with a long side of 15 to 80 mm is used, the number required for mounting corresponding to the pixel portion is as follows. This is less than when an IC chip is used, and the manufacturing yield can be improved. Further, when a driver IC is formed over a glass substrate, the shape of the substrate used as a base is not limited, and thus productivity is not impaired. This is a great advantage compared with the case where the IC chip is taken out from the circular silicon wafer.

In the case where the scan line side driver circuit 3702 is formed over the substrate as shown in FIG. 25B, a driver IC in which a signal line side driver circuit is formed is mounted in a region outside the pixel portion 3701. Is done. These driver ICs are drive circuits on the signal line side. In order to form a pixel region corresponding to RGB full color, the number of signal lines in the XGA class is 3072 and the number in the UXGA class is 4800. The signal lines formed in such a number are divided into several blocks at the end of the pixel portion 3701 to form lead lines, and are collected according to the pitch of the output terminals of the driver IC.

The driver IC is preferably formed of a crystalline semiconductor formed over a substrate, and the crystalline semiconductor is preferably formed by irradiating continuous-emitting laser light. Therefore, a continuous light emitting solid state laser or gas laser is used as an oscillator for generating the laser light. When a continuous light emission laser is used, a transistor can be formed using a polycrystalline semiconductor layer having a large grain size with few crystal defects. In addition, since the mobility and response speed are good, high-speed driving is possible, the operating frequency of the element can be improved as compared with the prior art, and there is less variation in characteristics, so that high reliability can be obtained. Note that for the purpose of further improving the operating frequency, the channel length direction of the transistor and the scanning direction of the laser light are preferably matched. This is because, in the laser crystallization process using a continuous-wave laser, the highest mobility is obtained when the channel length direction of the transistor and the scanning direction of the laser beam with respect to the substrate are substantially parallel (preferably −30 ° to 30 °). Is obtained. Note that the channel length direction corresponds to the direction in which current flows in the channel formation region, in other words, the direction in which charges move. The transistor manufactured in this way has an active layer composed of a polycrystalline semiconductor layer in which crystal grains extend in the channel length direction. This means that the crystal grain boundaries are formed substantially along the channel length direction. Means that.

In order to perform laser crystallization, it is preferable to significantly narrow down the laser beam, and the width of the laser beam shape (beam spot) should be about 1 mm to 3 mm, which is the same width of the short side of the driver IC. Is good. In order to ensure a sufficient and efficient energy density for the irradiated object, the laser light irradiation region is preferably linear. However, the line shape here does not mean a line in a strict sense, but means a rectangle or an ellipse having a large aspect ratio. For example, the aspect ratio is 2 or more (preferably 10 or more and 10,000 or less). In this manner, a method for manufacturing a display device with improved productivity can be provided by setting the width of the laser beam shape (beam spot) to the same length as the short side of the driver IC.

As shown in FIGS. 26A and 26B, driver ICs may be mounted as both the scanning line driver circuit and the signal line driver circuit. In that case, the specifications of the driver ICs used on the scanning line side and the signal line side may be different.

In the pixel region, the signal line and the scanning line intersect to form a matrix, and a transistor is arranged corresponding to each intersection. The present invention is characterized in that a TFT having an amorphous semiconductor or semi-amorphous semiconductor as a channel portion is used as a transistor disposed in a pixel region. The amorphous semiconductor is formed by a method such as a plasma CVD method or a sputtering method. A semi-amorphous semiconductor can be formed at a temperature of 300 ° C. or less by a plasma CVD method. For example, even a non-alkali glass substrate having an outer dimension of 550 × 650 mm has a film thickness necessary for forming a transistor. Is formed in a short time. Such a feature of the manufacturing technique is effective in manufacturing a large-screen display device. In addition, the semi-amorphous TFT can obtain a field effect mobility of ² to 10 cm ² / V · sec by forming a channel formation region with SAS. In addition, when the present invention is used, a pattern can be formed in a desired shape with good controllability, so that fine wiring can be stably formed without causing a defect such as a short circuit. Thus, a display panel that realizes system-on-panel can be manufactured.

By using TFTs in which the semiconductor layer is formed of SAS, the scanning line side driver circuit can also be integrally formed on the substrate. In the case of using TFTs in which the semiconductor layer is formed of AS, the scanning line side driver circuit and the signal A driver IC may be mounted on both the line side driver circuits.

In that case, it is preferable that the specifications of the driver ICs used on the scanning line side and the signal line side are different. For example, although a transistor constituting the driver IC on the scanning line side is required to have a withstand voltage of about 30 V, the driving frequency is 100 kHz or less, and a relatively high speed operation is not required. Therefore, it is preferable to set the channel length (L) of the transistors forming the driver on the scanning line side to be sufficiently large. On the other hand, it is sufficient for the transistor of the driver IC on the signal line side to have a withstand voltage of about 12V, but the drive frequency is about 65 MHz at 3V, and high speed operation is required. Therefore, it is preferable to set the channel length and the like of the transistors constituting the driver on the signal line side on the micron rule.

The method for mounting the driver IC is not particularly limited, and a COG method, a wire bonding method, or a TAB method can be used.

By setting the thickness of the driver IC to be the same as that of the counter substrate, the height between the two becomes substantially the same, which contributes to the reduction in thickness of the entire display device. In addition, since each substrate is made of the same material, thermal stress is not generated even when a temperature change occurs in the display device, and the characteristics of a circuit made of TFTs are not impaired. In addition, the number of driver ICs to be mounted in one pixel region can be reduced by mounting the drive circuit with a driver IC that is longer than the IC chip as shown in this embodiment.

As described above, a driver circuit can be incorporated in the display panel.

(Embodiment 13)
Examples of display panels (EL display panels and liquid crystal display panels) manufactured according to Embodiment Modes 4 to 11 in which a semiconductor layer is formed using an amorphous semiconductor or SAS and a driver circuit on the scan line side is formed over a substrate. Indicates.

FIG. 31 shows a block diagram of a scanning line side driving circuit constituted by an n-channel TFT using SAS capable of obtaining a field effect mobility of 1 to 15 cm ² / V · sec.

In FIG. 31, a block denoted by reference numeral 8500 corresponds to a pulse output circuit that outputs a sampling pulse for one stage, and the shift register includes n pulse output circuits. Reference numeral 8501 denotes a buffer circuit to which a pixel 8502 is connected.

FIG. 32 shows a specific structure of the pulse output circuit 8500, and the circuit is composed of n-channel TFTs 8601-8613. At this time, the size of the TFT may be determined in consideration of the operating characteristics of the n-channel TFT using SAS. For example, if the channel length is 8 μm, the channel width can be set in the range of 10 to 80 μm.

A specific configuration of the buffer circuit 8501 is shown in FIG. Similarly, the buffer circuit includes n-channel TFTs 8620 to 8635. At this time, the size of the TFT may be determined in consideration of the operating characteristics of the n-channel TFT using SAS. For example, if the channel length is 10 μm, the channel width is set in the range of 10 to 1800 μm.

In order to realize such a circuit, it is necessary to connect the TFTs by wiring.

As described above, a driver circuit can be incorporated in the display panel.

(Embodiment 14)
This embodiment will be described with reference to FIG. FIG. 16 shows an example in which an EL display module is formed using a TFT substrate 2800 manufactured by applying the present invention. In FIG. 16, a pixel portion including pixels is formed over the TFT substrate 2800.

In FIG. 16, the same TFT as that formed in the pixel or the gate of the TFT and one of the source and the drain is connected between the driving circuit and the pixel outside the pixel portion, and similar to the diode. The protection circuit portion 2801 operated in the above is provided. As the driver circuit 2809, a driver IC formed of a single crystal semiconductor, a stick driver IC formed of a polycrystalline semiconductor film over a glass substrate, a driver circuit formed of SAS, or the like is applied.

The TFT substrate 2800 is fixed to the sealing substrate 2820 through spacers 2806a and 2806b formed by a droplet discharge method. The spacer is preferably provided to keep the distance between the two substrates constant even when the substrate is thin and the area of the pixel portion is increased. Resin material having light-transmitting property at least in the visible region in the gap between the TFT substrate 2800 and the sealing substrate 2820 on the light-emitting element 2804 and the light-emitting element 2805 connected to the TFT 2802 and the TFT 2803, respectively. May be solidified by filling, or may be filled with anhydrous nitrogen or inert gas.

FIG. 16 shows a case where the light-emitting element 2804 and the light-emitting element 2805 are configured as an upward emission type (top emission type), in which light is emitted in the direction of the arrow shown in the drawing. Each pixel can perform multicolor display by changing the emission color of the pixels to red, green, and blue. At this time, by forming the colored layer 2807a, the colored layer 2807b, and the colored layer 2807c corresponding to each color on the sealing substrate 2820 side, the color purity of the emitted light can be increased. Alternatively, the pixel may be combined with a colored layer 2807a, a colored layer 2807b, or a colored layer 2807c as a white light emitting element.

A driver circuit 2809 which is an external circuit is connected to a scanning line or a signal line connection terminal provided at one end of the external circuit board 2811 through a wiring board 2810. Further, a heat pipe 2813 and a heat radiating plate 2812 which are pipe-like high-efficiency heat conduction devices used for transferring heat to the outside of the device in contact with or close to the TFT substrate 2800 are provided to enhance the heat radiation effect. It is good also as a structure.

In FIG. 16, the top emission EL module is used. However, the configuration of the light emitting element and the arrangement of the external circuit board may be changed to have a bottom emission structure, of course, a dual emission structure in which light is emitted from both the upper surface and the lower surface. In the case of a top emission type structure, an insulating layer serving as a partition wall may be colored and used as a black matrix. The partition walls can be formed by a droplet discharge method, and may be formed by mixing a resin material such as polyimide with a pigment-based black resin, carbon black, or the like, or may be a laminate thereof.

In addition, the EL display module may block reflected light of light incident from the outside using a retardation plate or a polarizing plate. In the case of an upward emission display device, an insulating layer serving as a partition wall may be colored and used as a black matrix. This partition wall can also be formed by a droplet discharge method or the like. Carbon black or the like may be mixed with a pigment-based black resin or a resin material such as polyimide, or may be laminated. A different material may be discharged to the same region a plurality of times by a droplet discharge method to form a partition wall. As the phase difference plate and the phase difference plate, a λ / 4 plate and a λ / 2 plate may be used and designed so that light can be controlled. As a structure, it becomes a structure called a light emitting element, a sealing substrate (sealing material), a phase difference plate, a phase difference plate (λ / 4 plate, λ / 2 plate), and a polarizing plate in order from the TFT element substrate side. The light emitted from the element passes through them and is emitted to the outside from the polarizing plate side. The retardation plate and the polarizing plate may be installed on the side from which light is emitted, and may be installed on both in the case of a dual emission type display device that emits both. Further, an antireflection film may be provided outside the polarizing plate. This makes it possible to display a higher-definition and precise image.

In the TFT substrate 2800, a sealing structure may be formed by attaching a resin film to the side where the pixel portion is formed using a sealing material or an adhesive resin. Although glass sealing using a glass substrate is described in this embodiment mode, various sealing methods such as resin sealing using a resin, plastic sealing using a plastic, and film sealing using a film can be used. A gas barrier film for preventing the permeation of water vapor may be provided on the surface of the resin film. By adopting a film sealing structure, further reduction in thickness and weight can be achieved.

This embodiment mode can be used in combination with each of Embodiment Modes 1 to 8, Embodiment 12, and Embodiment 13.

(Embodiment 15)
This embodiment will be described with reference to FIGS. 20A and 20B. 20A and 20B illustrate an example in which a liquid crystal display module is formed using a TFT substrate 2600 manufactured by applying the present invention.

FIG. 20A illustrates an example of a liquid crystal display module, in which a TFT substrate 2600 and a counter substrate 2601 are fixed to each other with a sealant 2602, and a pixel portion 2603 and a liquid crystal layer 2604 are provided therebetween to form a display region. The colored layer 2605 is necessary for color display. In the case of the RGB method, a colored layer corresponding to each color of red, green, and blue is provided corresponding to each pixel. Polarizing plates 2606 and 2607 and a diffusion plate 2613 are disposed outside the TFT substrate 2600 and the counter substrate 2601. The light source is composed of a cold cathode tube 2610 and a reflection plate 2611. The circuit board 2612 is connected to the TFT substrate 2600 by a flexible wiring board 2609, and an external circuit such as a control circuit or a power supply circuit is incorporated. Moreover, you may laminate | stack in the state which had the phase difference plate between the polarizing plate and the liquid-crystal layer.

The liquid crystal display module includes TN (Twisted Nematic) mode, IPS (In-Plane-Switching) mode, FFS (Fringe Field Switching) mode, MVA (Multi-domain Vertical Alignment) mode, PVA (SMB) Axial Symmetrically Aligned Micro-cell (OCB) mode, OCB (Optical Compensated Birefringence) mode, FLC (Ferroelectric Liquid Crystal) mode, AFLC (Anti-Ferroelectric Liquid Liquor) Door can be.

FIG. 20B is an example in which the OCB mode is applied to the liquid crystal display module of FIG. 20A, and is an FS-LCD (Field sequential-LCD). The FS-LCD emits red light, green light, and blue light in one frame period, and can perform color display by combining images using time division. Further, since each light emission is performed by a light emitting diode or a cold cathode tube, a color filter is unnecessary. Therefore, it is not necessary to arrange the color filters of the three primary colors and limit the display area of each color, and it is possible to display all three colors in any area. On the other hand, since the three colors emit light in one frame period, a high-speed response of the liquid crystal is required. By applying the FLC mode using the FS method and the OCB mode to the display device of the present invention, a high-performance and high-quality display device and a liquid crystal television device can be completed.

The liquid crystal layer in the OCB mode has a so-called π cell structure. The π cell structure is a structure in which the pretilt angles of liquid crystal molecules are aligned in a plane-symmetric relationship with respect to the center plane between the active matrix substrate and the counter substrate. The alignment state of the π cell structure is splay alignment when no voltage is applied between the substrates, and shifts to bend alignment when a voltage is applied. This bend orientation is white. When a voltage is further applied, the bend-aligned liquid crystal molecules are aligned perpendicularly to both substrates, and light is not transmitted. In the OCB mode, high-speed response that is about 10 times faster than the conventional TN mode can be realized.

Further, as a mode corresponding to the FS method, HV (Half V) -FLC using a ferroelectric liquid crystal (FLC) capable of high-speed operation, SS (Surface Stabilized) -FLC, or the like can be used. . A nematic liquid crystal having a relatively low viscosity is used for the OCB mode, and a smectic liquid crystal having a ferroelectric phase can be used for HV-FLC and SS-FLC.

In addition, the high-speed optical response speed of the liquid crystal display module is increased by narrowing the cell gap of the liquid crystal display module. The speed can also be increased by reducing the viscosity of the liquid crystal material. The increase in speed is more effective when the pixel pitch of the pixel region of the TN mode liquid crystal display module is 30 μm or less. Further, the speed can be further increased by the overdrive method in which the applied voltage is increased (or decreased) for a moment.

The liquid crystal display module in FIG. 20B is a transmissive liquid crystal display module, and a red light source 2910a, a green light source 2910b, and a blue light source 2910c are provided as light sources. The light source is provided with a controller 2912 for controlling on / off of the red light source 2910a, the green light source 2910b, and the blue light source 2910c. The light emission of each color is controlled by the control unit 2912, light enters the liquid crystal, an image is synthesized using time division, and color display is performed.

As described above, when the present invention is used, a highly delicate and highly reliable liquid crystal display module can be manufactured.

This embodiment mode can be used in combination with each of Embodiment Modes 1 to 3 and Embodiments 9 to 13.

(Embodiment 16)
With the display device formed according to the present invention, a television device (also simply referred to as a television or a television receiver) can be completed. FIG. 27 is a block diagram showing a main configuration of the television device.

FIG. 25A is a top view illustrating a structure of a display panel according to the present invention. A pixel portion 2701 in which pixels 2702 are arranged in a matrix over a substrate 2700 having an insulating surface, a scan line side input terminal 2703, a signal A line side input terminal 2704 is formed. The number of pixels may be provided in accordance with various standards. For full color display using XGA and RGB, 1024 × 768 × 3 (RGB), and for full color display using UXGA and RGB, 1600 × 1200. If it corresponds to x3 (RGB) and full spec high vision and is full color display using RGB, it may be set to 1920 x 1080 x 3 (RGB).

The pixels 2702 are arranged in a matrix by a scan line extending from the scan line side input terminal 2703 and a signal line extending from the signal line side input terminal 2704 intersecting. Each pixel of the pixel portion 2701 is provided with a switching element and a pixel electrode layer connected to the switching element. A typical example of a switching element is a TFT. By connecting the gate electrode layer side of the TFT to a scanning line and the source or drain side to a signal line, each pixel can be controlled independently by a signal input from the outside. It is said.

FIG. 25A shows the structure of a display panel in which signals input to the scan lines and signal lines are controlled by an external driver circuit. As shown in FIG. 26A, COG (Chip on The driver IC 2751 may be mounted on the substrate 2700 by a glass method. As another mounting mode, a TAB (Tape Automated Bonding) method as shown in FIG. 26B may be used. The driver IC may be formed on a single crystal semiconductor substrate or may be a circuit in which a TFT is formed on a glass substrate. In FIG. 26, the driver IC 2751 is connected to an FPC (Flexible Printed Circuit) 2750.

In the case where a TFT provided for a pixel is formed using a crystalline semiconductor, the scan line driver circuit 3702 can be formed over the substrate 3700 as shown in FIG. In FIG. 25B, the pixel portion 3701 is controlled by an external driver circuit as in FIG. 25A connected to the signal line side input terminal 3704. In the case where a TFT provided for a pixel is formed using a polycrystalline (microcrystalline) semiconductor, a single crystal semiconductor, or the like with high mobility, as illustrated in FIG. 25C, a pixel portion 4701, a scan line driver circuit 4702, The signal line driver circuit 4704 can be formed over the substrate 4700 as a single body.

In the display panel, as shown in FIG. 25A, only the pixel portion 901 in FIG. 27 is formed, and the scan line side driver circuit 903 and the signal line side driver circuit 902 are replaced with each other in FIG. The TFT is formed as shown in FIG. 25B when mounted by the TAB method as shown in FIG. 26A, when mounted by the COG method as shown in FIG. In the case where the driver circuit 903 is formed over the substrate and the signal line driver circuit 902 is separately mounted as a driver IC, as shown in FIG. 25C, the pixel portion 901, the signal line driver circuit 902, and the scanning line driver circuit There is a case where 903 is integrally formed on the substrate, but any form is possible.

27, as other external circuit configurations, on the video signal input side, among the signals received by the tuner 904, the video signal amplification circuit 905 that amplifies the video signal and the signal output therefrom are red, green, and so on. , A video signal processing circuit 906 for converting into a color signal corresponding to each color of blue, a control circuit 907 for converting the video signal into an input specification of the driver IC, and the like. The control circuit 907 outputs signals to the scanning line side and the signal line side, respectively. In the case of digital driving, a signal dividing circuit 908 may be provided on the signal line side so that an input digital signal is divided into m pieces and supplied.

Of the signals received by the tuner 904, the audio signal is sent to the audio signal amplifier circuit 909, and the output is supplied to the speaker 913 via the audio signal processing circuit 910. The control circuit 911 receives control information on the receiving station (reception frequency) and volume from the input unit 912 and sends a signal to the tuner 904 and the audio signal processing circuit 910.

As shown in FIGS. 28A and 28B, these display modules can be incorporated into a housing to complete a television device. If a liquid crystal display module is used as the display module, a liquid crystal television device can be manufactured. If an EL module is used, an EL television device, a plasma television, an electronic paper, or the like can be manufactured. In FIG. 28A, a main screen 2003 is formed using a display module, and a speaker portion 2009, operation switches, and the like are provided as accessory equipment. Thus, a television device can be completed according to the present invention.

A display panel 2002 is incorporated in a housing 2001, and general television broadcasting is received by a receiver 2005, and connected to a wired or wireless communication network via a modem 2004 (one direction (from a sender to a receiver)). ) Or bi-directional (between the sender and the receiver, or between the receivers). The television device can be operated by a switch incorporated in the housing or a separate remote control device 2006, and the remote control device 2006 also includes a display unit 2007 for displaying information to be output. good.

In addition, the television device may have a configuration in which a sub screen 2008 is formed using the second display panel in addition to the main screen 2003 to display channels, volume, and the like. In this configuration, the main screen 2003 and the sub-screen 2008 can be formed using the liquid crystal display panel of the present invention, the main screen 2003 is formed using an EL display panel with an excellent viewing angle, and the sub-screen has low power consumption. It may be formed of a liquid crystal display panel that can be displayed with In order to prioritize the reduction in power consumption, the main screen 2003 may be formed using a liquid crystal display panel, the sub screen may be formed using an EL display panel, and the sub screen may blink. When the present invention is used, a highly reliable display device can be obtained even when such a large substrate is used and a large number of TFTs and electronic components are used.

FIG. 28B illustrates a television device having a large display portion of 20 to 80 inches, for example, which includes a housing 2010, a display portion 2011, a remote control device 2012 that is an operation portion, a speaker portion 2013, and the like. The present invention is applied to manufacture of the display portion 2011. The television device in FIG. 28B is a wall-hanging type and does not require a large installation space.

Of course, the present invention is not limited to a television device, but can be applied to various uses such as a monitor for a personal computer, an information display board in a railway station or airport, an advertisement display board in a street, etc. can do.

This embodiment mode can be freely combined with any of Embodiment Modes 1 to 15 as appropriate.

(Embodiment 17)
As electronic devices according to the present invention, portable information such as a television device (also simply referred to as a television or a television receiver), a digital camera, a digital video camera, a cellular phone device (also simply referred to as a cellular phone or a cellular phone), a PDA, etc. Examples include a terminal, a portable game machine, a computer monitor, a computer, an audio playback device such as a car audio, and an image playback device including a recording medium such as a home game machine. A specific example will be described with reference to FIG.

A portable information terminal device illustrated in FIG. 29A includes a main body 9201, a display portion 9202, and the like. The display device of the present invention can be applied to the display portion 9202. As a result, since it can be manufactured at a low cost with a simplified process, a highly reliable portable information terminal device can be provided at a low price.

A digital video camera shown in FIG. 29B includes a display portion 9701, a display portion 9702, and the like. The display device of the present invention can be applied to the display portion 9701. As a result, a highly reliable digital video camera can be provided at a low price because it can be manufactured at a low cost with a simplified process.

A cellular phone shown in FIG. 29C includes a main body 9101, a display portion 9102, and the like. The display device of the present invention can be applied to the display portion 9102. As a result, a highly reliable mobile phone can be provided at a low price because it can be manufactured at a low cost with a simplified process.

A portable television device illustrated in FIG. 29D includes a main body 9301, a display portion 9302, and the like. The display device of the present invention can be applied to the display portion 9302. As a result, a highly reliable television device can be provided at a low price because it can be manufactured at a low cost with a simplified process. In addition, the present invention can be applied to a wide variety of television devices, from a small one mounted on a portable terminal such as a cellular phone to a medium-sized one that can be carried and a large one (for example, 40 inches or more). The display device can be applied.

A portable computer shown in FIG. 29E includes a main body 9401, a display portion 9402, and the like. The display device of the present invention can be applied to the display portion 9402. As a result, a highly reliable computer can be provided at a low price because it can be manufactured at a low cost with a simplified process.

As described above, the display device of the present invention can provide a high-performance electronic device that can display a high-quality image with excellent visibility.

This embodiment mode can be freely combined with any of Embodiment Modes 1 to 16 as appropriate.

In this embodiment, an example in which an opening is formed in an insulating layer using the present invention will be described.

A stack of a conductive layer, a light absorption layer, and an insulating layer was formed on a glass substrate. Using a sputtering method, a molybdenum film (thickness 300 nm) as a conductive layer, a chromium film (thickness 20 nm) as a light absorption layer, and a silicon oxynitride film (thickness 1000 nm) which is a silicon film containing nitrogen as an insulating layer, respectively. Formed.

Laser light was irradiated from the insulating layer side through the insulating layer to the light absorption layer. The laser light was absorbed by the light absorption layer, the heat was conducted to the insulating layer, and an opening was formed in the insulating layer. In this embodiment, when the fundamental wave of a continuous wave YAG laser is used as the laser beam, the opening to the insulating layer is performed when the second harmonic and the third harmonic of the pulsed YAG laser are used.

When the fundamental wave of a continuous wave YAG laser was used as the laser light, the laser irradiation conditions were a laser output of 480 W and an irradiation time of 1.4 ms. Since the diameter of the opening was 100 μm, it was 3 × 10 ⁵ W / cm ² in terms of energy density (5 × 10 ² J / cm ^{2 in} terms of joule).

When the second harmonic and the third harmonic of a pulsed YAG laser were used as the laser light, the laser irradiation conditions were a laser output of 2 μJ and a laser pulse width of 5 ns. Since the diameter of the opening was 15 μm, it was about 2 × 10 ⁸ W / cm ² (1 J / cm ^{2 in} terms of joule) when converted to energy density.

As shown in this embodiment, even if the insulating layer does not absorb the laser light using the present invention, the light absorbing layer is formed under the insulating layer, so that the laser light is transmitted to the light absorbing layer through the insulating layer. It was confirmed that an opening could be formed in the insulating layer by irradiation.

Since openings can be selectively formed by laser light, a mask layer is not required and processes and materials can be reduced. In addition, since the laser beam can be focused on a very small spot, the conductive layer and insulating layer to be processed can be processed into a predetermined shape with high accuracy and can be heated instantaneously in a short time. There is an advantage that almost no heating is required.

Thus, an opening (contact hole) for electrically connecting the conductive layer and the conductive layer can be formed in the insulating layer by laser light irradiation without performing a complicated photolithography process and formation of a mask layer.

Therefore, when a display device is manufactured using the present invention, the process can be simplified, so that material loss is small and cost reduction can be achieved. Thus, a display device can be manufactured with high yield.

The conceptual diagram explaining this invention. The conceptual diagram explaining this invention. The conceptual diagram explaining this invention. The conceptual diagram explaining this invention. 6A and 6B illustrate a display device of the present invention. 6A and 6B illustrate a display device of the present invention. 6A and 6B illustrate a display device of the present invention. 4A to 4D illustrate a method for manufacturing a display device of the present invention. 4A to 4D illustrate a method for manufacturing a display device of the present invention. 4A to 4D illustrate a method for manufacturing a display device of the present invention. 4A to 4D illustrate a method for manufacturing a display device of the present invention. 4A to 4D illustrate a method for manufacturing a display device of the present invention. 4A to 4D illustrate a method for manufacturing a display device of the present invention. 4A to 4D illustrate a method for manufacturing a display device of the present invention. 6A and 6B illustrate a display device of the present invention. Sectional drawing explaining the structural example of the display module of this invention. 6A and 6B illustrate a display device of the present invention. 6A and 6B illustrate a display device of the present invention. 6A and 6B illustrate a display device of the present invention. Sectional drawing explaining the structural example of the display module of this invention. 6A and 6B illustrate a display device of the present invention. 3A and 3B each illustrate a structure of a light-emitting element that can be applied to the present invention. 3A and 3B each illustrate a structure of a light-emitting element that can be applied to the present invention. 3A and 3B each illustrate a structure of a light-emitting element that can be applied to the present invention. The top view of the display apparatus of this invention. The top view of the display apparatus of this invention. 1 is a block diagram illustrating a main configuration of an electronic device to which the present invention is applied. FIG. 11 illustrates an electronic device to which the present invention is applied. FIG. 11 illustrates an electronic device to which the present invention is applied. 1A and 1B illustrate a structure of a laser beam direct drawing apparatus that can be applied to the present invention. 4A and 4B each illustrate a circuit structure in the case where a scan line side driver circuit is formed using TFTs in a display panel of the present invention; 4A and 4B illustrate a circuit structure in the case where a scan line driver circuit is formed using TFTs in a display panel of the present invention (shift register circuit). 4A and 4B illustrate a circuit configuration in the case where a scan line side driver circuit is formed using TFTs in a display panel of the present invention (buffer circuit).

Claims (7)

Forming a light absorption layer,
Forming an insulating layer on the light absorbing layer;
Selectively irradiating the light absorption layer and the insulating layer with laser light, removing an irradiation region of the insulating layer to form an opening in the insulating layer;
A manufacturing method of a display device, wherein a conductive film is formed in the opening so as to be in contact with the light absorption layer. Forming a conductive layer,
Forming a light absorption layer on the conductive layer;
Forming an insulating layer on the light absorbing layer;
Selectively irradiating the light absorption layer and the insulating layer with laser light, removing an irradiation region of the insulating layer to form an opening in the insulating layer;
A manufacturing method of a display device, wherein a conductive film is formed in the opening so as to be in contact with the light absorption layer. 3. The method for manufacturing a display device according to claim 1, wherein the light absorption layer is formed using a conductive material. 4. The method for manufacturing a display device according to claim 3, wherein the light absorption layer is formed using one or more of chromium, tantalum, silver, molybdenum, nickel, titanium, cobalt, copper, and aluminum. 3. The method for manufacturing a display device according to claim 1, wherein the light absorption layer is formed using a semiconductor material. 6. The method for manufacturing a display device according to claim 5, wherein the light absorption layer is formed using silicon. 7. The method for manufacturing a display device according to claim 1, wherein the insulating layer transmits the laser light.

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