JP2002289356A - Luminescence equipment and its producing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element structure, which enables to make average film resistance in a positive electrode of a light emitting element low resistance, in active-matrix type luminescence equipment. SOLUTION: By forming an upper part 107b of a bank 107, which is formed so that between a negative electrode 104 may be filled, with an electric conduction film, the average film resistance in the positive electrode 109 can be made low resistance, and the luminescence equipment of clearer picture display can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a light-emitting device having a film containing an organic compound capable of emitting light by applying an electric field (hereinafter referred to as "organic compound layer"), an anode, and a cathode. The present invention relates to a film forming apparatus and a film forming method used. In particular, the present invention relates to the manufacture of a light-emitting element which is less likely to deteriorate than a conventional one and has a long lifetime.

[0002]

2. Description of the Related Art In recent years, research on light-emitting devices having organic light-emitting elements (light-emitting elements) as self-luminous elements has been actively conducted. In particular, light-emitting devices using organic compounds as light-emitting materials have attracted attention. . This light emitting device is an organic electroluminescent display (OELD: Organic EL Display) or an organic light emitting diode (OLED: Organic Light Emitting Dio).
de).

[0003] A light-emitting element includes a layer containing an organic compound capable of obtaining luminescence (Electro Luminescence) generated by applying an electric field (hereinafter referred to as an organic compound layer).
, An anode, and a cathode. Luminescence of an organic compound includes light emission (fluorescence) when returning from a singlet excited state to a ground state and light emission (phosphorescence) when returning to a ground state from a triplet excited state. It can be applied to the case where either light emission is used.

[0004] Unlike a liquid crystal display device, a light emitting device is of a self-luminous type, and thus has a feature that there is no problem of a viewing angle. That is, as a display used outdoors, it is more suitable than a liquid crystal display, and its use in various forms has been proposed.

[0005] The light-emitting element has a structure in which an organic compound layer is sandwiched between a pair of electrodes. The organic compound layer usually has a laminated structure. A typical example is a laminated structure of “hole transport layer / light emitting layer / electron transport layer” proposed by Tang et al. Of Kodak Eastman Company. This structure has a very high luminous efficiency, and most light emitting devices currently under research and development are adopting this structure.

In addition, a hole injection layer / hole transport layer / light-emitting layer / electron transport layer, or a hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer may be formed on the anode. A structure in which layers are sequentially stacked is also good. The light emitting layer may be doped with a fluorescent dye or the like. Further, these layers may be all formed using a low molecular material, or all may be formed using a high molecular material.

[0007] In the present specification, all layers provided between the cathode and the anode are collectively referred to as an organic compound layer. Therefore, the above-described hole injection layer, hole transport layer, light emitting layer, electron transport layer, and electron injection layer are all included in the organic compound layer. An element formed of a cathode, an organic compound layer, and an anode is called a light-emitting element, and includes a method in which an organic compound layer is formed between two types of striped electrodes provided so as to be orthogonal to each other. (Simple matrix type)
And a method of forming an organic compound layer between a cathode and an anode connected to a TFT and arranged in a matrix (active matrix type).

Particularly, in the active matrix type, a current flowing through a light emitting element provided in each pixel is supplied to a TF provided in the pixel.
Many studies have been made because they can be controlled by T and high-definition display is possible.

Further, in an active matrix type light emitting device, an electrode electrically connected to a TFT on a substrate is formed as an anode, an organic compound layer is formed on the anode, and a cathode is formed on the organic compound layer. It had a light emitting element to be formed, and had a structure in which light generated in the organic compound layer was extracted from the anode, which is a transparent electrode, toward the TFT.

However, in this structure, there is a problem that the aperture ratio is limited by the arrangement of the TFTs and the wirings in the pixel portion in order to improve the resolution.

[0011]

Therefore, in order to solve the above-mentioned problems, in the present invention, an electrode on the TFT side electrically connected to the TFT on the substrate is formed as a cathode, and an organic compound layer is formed on the cathode. Then, an active matrix light-emitting device including a light-emitting element having a structure in which an anode which is a transparent electrode is formed over an organic compound layer (hereinafter, referred to as a top emission structure) is manufactured.

However, when a light emitting device having a top emission structure is manufactured, a problem arises that the film resistance of the anode is increased. When the film resistance of the anode increases, the voltage drop causes the in-plane potential distribution of the anode to become non-uniform, which causes a problem that the luminance of the light emitting element varies. Therefore, an object of the present invention is to provide a light-emitting device having a structure in which the film resistance of an anode in a light-emitting element is reduced, and a manufacturing method thereof. Then, it is an object to provide an electric appliance using such a light emitting device as a display portion.

[0013]

According to the present invention, an electrode electrically connected to a TFT formed on a substrate is used as a cathode, an organic compound layer is formed on the cathode, and an anode is formed on the organic compound layer. In manufacturing a light emitting device, a conductive film is formed before the anode is formed, and the film resistance of the anode is reduced.

Therefore, a light emitting device and a method for manufacturing the same according to the present invention will be described with reference to FIGS. In FIG. 1A, a TFT 101 is formed over a substrate 100. Note that the substrate 100 is an insulator, and is a substrate having an insulator on its surface, an insulating substrate, or an insulating film. The TFT 101 is a TFT (current control TFT) for controlling a current flowing through the light emitting element.

Further, a first insulating film 102 is formed so as to cover the TFT 101. As a material for forming the first insulating film 102, in addition to inorganic materials containing silicon such as silicon oxide, silicon nitride, and silicon oxynitride, polyimide,
Polyamide, acrylic, BCB (benzocyclobutene)
It is possible to use such an organic material.

The cathode 1 formed on the first insulating film 102
04 and the TFT 101 are electrically connected. Although the case where the wiring to the TFT 101 is formed at the same time as the formation of the cathode 104 is described here, the cathode and the wiring can be formed separately from different materials.

In the present invention, since the cathode 104 serves as a cathode, it is desirable to use aluminum having a small work function or an aluminum alloy such as Al: Li. In the case where the cathode 104 also serves as a wiring, it is preferable that the cathode 104 be formed using a metal having low resistivity.

Next, as shown in FIG.
A second insulating film 105 is formed thereover. Note that as a material for forming the second insulating film 105, in addition to an inorganic material containing silicon such as silicon oxide, silicon nitride, and silicon oxynitride,
Organic materials such as polyimide, polyamide, acrylic, and BCB (benzocyclobutene) can be used, and a vapor deposition method, a CVD method, a sputtering method, a spin coating method,
The film can be formed by a film formation method such as an ink-jet method and a printing method. Note that the second insulating film 105 has a thickness of 0.
It is desirable that the film is formed to have a thickness of 1 to 3 μm.

Further, the conductive film 1 is formed on the second insulating film 105.
06 is formed. As the conductive film 106, a conductive material with low resistance such as aluminum, titanium, or tantalum may be used. Note that since the conductive film is formed without covering the cathode, the conductive film does not necessarily need to be light-transmitting and may be light-blocking. The conductive film 106 formed here
Functions as a conductive film that lowers the film resistance of the anode at a contact portion 110 with the anode of the light emitting element to be formed later.

Further, in this specification, the film resistance of the entire anode obtained by averaging the film resistance of the contact portion and the film resistance of only the anode, that is, the film resistance of the entire portion electrically connected to the anode is referred to as the anode resistance. When the conductive film 106 is provided under the anode, the average film resistance at the anode can be reduced. Further, the conductive film 10
When 6 is made of a light-shielding material, it also functions as a light-shielding film.

As a method for forming the conductive film 106, a sputtering method or an evaporation method can be used.

Next, as shown in FIG.
An opening is formed on the cathode by etching the second insulating film 105 and the conductive film 106 formed thereon, respectively. Note that in the present invention, either a dry etching method or a wet etching method can be used, and the method may be appropriately selected depending on a material for forming the second insulating film 105 and the conductive film 106.

Further, an organic compound layer 1 is formed in the opening on the cathode.
08 is formed. The organic compound for forming the organic compound layer may be a low molecular material or a high molecular material, and may be formed using a known material in a single layer or a combination of a plurality of these layers. can do.

In the present invention, in order to form a plurality of organic compound layers that emit different light, a vapor deposition method, an ink-jet method, a printing method, or the like that can be separately applied to each pixel using a metal mask can be used. .

Before forming the organic compound layer 108, an insulating compound containing an alkali metal or an alkaline earth metal (hereinafter, referred to as an alkali compound) may be formed on all the cathodes. . Examples of the alkali compound include lithium fluoride (LiF), lithium oxide (Li ₂ O), barium fluoride (BaF ₂ ), barium oxide (BaO), calcium fluoride (CaF ₂ ), calcium oxide (CaO), and strontium oxide. (SrO) or cesium oxide (Cs ₂ O) can be used.

Next, an anode 109 is formed on the organic compound layer 108 as shown in FIG. Note that a transparent conductive film is used for the anode 109, and a compound of indium oxide and tin oxide (called ITO), a compound of indium oxide and zinc oxide, tin oxide, zinc oxide, or the like is used as the transparent conductive film. Is possible.

The anode 109 is formed as a common electrode for a plurality of light emitting elements included in the pixel portion, and has a structure in which the anode 109 and the conductive film are in contact at a position where the anode 109 and the organic compound layer 108 do not overlap. That is, in the contact portion 110, the film resistance of the transparent conductive film forming the anode decreases.

By implementing the present invention, a light emitting device having a light emitting element having a structure in which light generated in the organic compound layer 108 is taken out in the direction of the arrow is formed, and the problem of lowering the film resistance at the anode is solved. be able to.

Although the method in which the upper portion of the bank is formed of a conductive film has been described herein, the present invention is not limited to this, and the opening is formed in the second insulating film formed of only an insulating material. After forming the part and forming the organic compound layer,
A conductive film may be formed over the second insulating film using a metal mask, and may be in contact with an anode formed later, so that the film resistance of the anode can be reduced.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a light emitting device of the present invention and a method for manufacturing the same will be described below.

FIG. 2 shows an example of a block diagram of a light emitting device. The light-emitting device in FIG. 2 includes a pixel portion 201 using a TFT formed over a substrate, a source signal line driving circuit 202 arranged around the pixel portion, a writing gate signal line driving circuit (a first gate signal line driving circuit). ) 203, erase gate signal line drive circuit (second gate signal line drive circuit) 204
have. Note that although the light emitting device has one source signal line driver circuit in this embodiment mode, the present invention may have two source signal line driver circuits.

In the present invention, the source signal side driving circuit 202, the writing gate signal side driving circuit 203 or the erasing gate signal line driving circuit 204 includes the pixel section 201.
May be provided on a substrate provided with, or may be provided on an IC chip and connected to the pixel portion 201 via FPC or TAB.

The source signal line drive circuit 202 basically has a shift register 202a, a latch (A) 202b, and a latch (B) 202c.

In the source signal line driving circuit 202, a clock signal (CLK) and a start pulse (SP) are input to the shift register 202a. The shift register 202a sequentially generates a timing signal based on the clock signal (CLK) and the start pulse (SP), and sequentially supplies the timing signal to a subsequent circuit through a buffer or the like (not shown).

The timing signal from the shift register 202a is buffer-amplified by a buffer or the like. The wiring to which the timing signal is supplied has a large load capacitance (parasitic capacitance) because many circuits or elements are connected. This buffer is provided to prevent "dulling" of the rise or fall of the timing signal caused by the large load capacitance.

The timing signal buffer-amplified by the buffer is supplied to the latch (A) 202b. The latch (A) 202b outputs a digital data signal (digital data signal).
signals) for processing a plurality of stages. When the timing signal is input, the latch (A) 202b sequentially captures and holds the digital data signal supplied from the time-division grayscale data signal generation circuit 206.

When a digital data signal is taken into the latch (A) 202b, the digital data signal may be sequentially input to a plurality of stages of latches of the latch (A) 202b. However, the present invention is not limited to this configuration.

The time until the writing of the digital data signal to the latches of all the stages of the latch (A) 202b is completed is called a line period. That is, a time interval from the time when the writing of the digital data signal to the latch of the leftmost stage in the latch (A) 202b starts to the time when the writing of the digital data signal to the latch of the rightmost stage ends. Is a line period.
Actually, the line period may include a period obtained by adding the horizontal retrace period to the line period.

When one line period ends, the latch (B)
A latch signal (LatchSignal) is supplied to 202c. At this moment, the digital data signal written and held in the latch (A) 202b is
c, and is written to and held in the latches of all the stages of the latch (B) 202c.

The digital data signal is latched (B) 202
The digital data signal supplied from the time-division grayscale data signal generation circuit 206 is sequentially written into the latch (A) 202b which has finished sending the data to the latch (A) 202b, based on the timing signal from the shift register 202a.

During the second one line period, the digital data signal written and held in the latch (B) 202b is input to the source signal line.

On the other hand, the write gate signal line drive circuit 2
03 and the erase gate signal line drive circuit 204 each have a shift register and a buffer (both not shown). In some cases, the write gate signal line drive circuit 203 and the erase gate signal line drive circuit 20
4 may have a level shift in addition to the shift register and the buffer.

In the write gate signal line drive circuit 203 and the erase gate signal line drive circuit 204, a timing signal from a shift register (not shown) is supplied to a buffer (not shown), and a corresponding gate signal line ( Scan lines). The gate signal lines are connected to the gate electrodes of pixel TFTs for one line, and all pixel TFTs for one line must be turned on at the same time. Used.

In the time division gray scale data signal generation circuit 206, an analog or digital video signal (a signal including image information) is used to perform a time division gray scale by a digital data signal (Digital Data Signals).
And input to the latch (A) 202b. The time-division grayscale data signal generation circuit 206 is also a circuit that generates timing pulses and the like necessary for performing time-division grayscale display.

Although not shown here, the pixel section 20
1 is a latch (B) 2 of the source signal line driving circuit 202.
02c, a current supply line connected to a power supply external to the light emitting device via the FPC, and a write gate signal line (first gate signal) connected to the write gate signal line driving circuit 203. Line) and an erasing gate signal line (a second gate signal line) connected to the erasing gate signal line driving circuit 204 are provided in the pixel portion 201.

Note that a region provided with a source signal line, a current supply line, a write gate signal line, and an erase gate signal line is the pixel 205. That is, a plurality of pixels 205 are arranged in a matrix in the pixel portion 201.

According to the present invention, in a light emitting device having the above-described structure, a conductive film is formed so as to be in contact with an anode when a plurality of pixels 205 are formed in the pixel portion 201, and the film resistance of the anode is reduced. It is related to a method for making it. Note that a plurality of pixels 205 included in the pixel portion 201 are formed in the region 206 in FIG. Note that the light-emitting element of the present invention and a method for manufacturing the light-emitting element will be described with reference to FIGS.

FIG. 3A is a top view of the region 206, and FIG. 3B is a cross-sectional view of FIG. 3A taken along the line PP ′.

In FIG. 3A, a plurality of pixels are formed, and a cathode 301 serving as a cathode is formed at the uppermost portion. Reference numeral 302 shown by a dotted line denotes a source signal line, which is connected to the source signal line driving circuit. Reference numeral 303 indicated by a dotted line denotes a current supply line,
It is connected to a power supply external to the light emitting device via C.

In the present invention, since the cathode and the wiring can be formed simultaneously, Al, Ti, W, Al-S
i, and a current controlling TFT 3 formed on a substrate 300 using a material such as an alloy such as Al: Li.
04 is electrically connected. The current control TFT
Are formed in each pixel, and serve to supply a current from a current supply line to a light emitting element. Although not shown here, each pixel has a switching TFT.
And an erasing TFT are also formed.

A bank 305 is formed so as to fill a gap between the cathodes 301. The bank 305
Has a laminated structure of a layer made of an insulating material and a layer made of a conductive material.

As a method for manufacturing the bank 305, an insulating material is formed to a thickness of 0.5 to 5 μm on a substrate formed up to the cathode, and then a conductive material such as metal is coated for 10 to 300 nm.
m (preferably 40 to 80 nm).

As the insulating material, besides inorganic materials containing silicon such as silicon oxide, silicon nitride and silicon oxynitride, organic materials such as acrylic, polyimide, polyamide and BCB (benzocyclobutene) can be used.

As a method of forming the insulating material, in the case of an inorganic material, a vapor deposition method, a CVD method, or a sputtering method is preferable. In the case of an organic material, a spin coating method, an ink jet method, or the like is used. be able to.

As the conductive material, a material having low resistivity (also referred to as specific resistance) is used. In this specification, a conductive material having a low resistivity refers to a material having a sheet resistance of 0.01 to 1 Ω / □. Specifically, titanium (Ti), aluminum (Al), tantalum (T
a), tungsten (W), chromium (Cr), copper (C
u) or a material such as silver (Ag) can be used.
Note that the material and the thickness of the conductive film may be appropriately selected and used so that the film resistance of the conductive film is lower than the film resistance of the anode 309.

It is preferable that the conductive material is formed by a vapor deposition method or a sputtering method.

Second interlayer insulating film 306 and conductive film 307
Is formed, an opening is formed at a position corresponding to the cathode 301 by etching the second interlayer insulating film 306 and the conductive film 307.

The etching here can be a dry etching method such as an ICP etching method or an RIE (reactive ion etching) method or a wet etching method.

As an etching gas, a gas such as Ar, O ₂ , He or the like is used in addition to a fluorine-based gas or a chlorine-based gas, and a plurality of these gases are mixed. Then, etching is performed.

Then, the second insulating film 306 and the conductive film 307 left after the etching for forming the opening are referred to as a bank 305 in this specification.

Next, as shown in FIGS. 4A and 4B, an organic compound layer 308 (308R,
308G, 308B) are formed. Here, an aspect is shown in which three types of organic compound layers that emit light are formed in the vertical direction toward the paper surface. FIG. 4B
FIG. 4 is a cross-sectional view taken along a line PP ′ in FIG.

These organic compound layers are formed of known organic compounds such as an organic compound having an electron transporting property, an organic compound having a blocking property, an organic compound having a light emitting property, a host material, an organic compound having a hole transporting property and an organic compound having a hole injecting property. Organic compounds can be freely combined and used.

Here, the case where the organic compound layers showing three kinds of light emission are formed in the vertical direction toward the paper surface is shown. However, the present invention is not limited to this, and differs in the vertical direction. It is also possible to form an organic compound layer.

As a method for forming the organic compound layer 308, a vapor deposition method, an ink jet method, a printing method, or the like can be used.

An anode 309 of a light emitting element is formed on a substrate on which an organic compound layer 308 is formed. A cross-sectional view at this time is shown in FIG.

As the anode 309, a transparent conductive film of 80 to 1
The film is formed with a thickness of 20 nm. For example, an indium tin oxide (ITO) film or a transparent conductive film in which indium oxide is mixed with 2 to 20% of zinc oxide (ZnO) can be used. In addition, as a film forming method, a film can be formed by an ion plating method in addition to a vapor deposition method or a sputtering method. However, since an anode is formed after an organic compound layer is formed, a vapor deposition method or an ion plating method is used. It is desirable to use the marking method.

[0067]

[Embodiment 1] In this embodiment, a pixel portion and a driving circuit TFT (an n-channel TFT and a p-channel TFT) provided around the pixel portion are simultaneously formed on the same substrate. A method for forming a light-emitting element electrically connected to a TFT in a pixel portion and manufacturing an element substrate will be described with reference to FIGS.

First, in this embodiment, Corning # 70
A substrate 600 made of glass such as barium borosilicate glass represented by 59 glass or # 1737 glass, or aluminoborosilicate glass is used. Note that the substrate 600 is not limited as long as it is a light-transmitting substrate, and a quartz substrate may be used. Further, a plastic substrate having heat resistance enough to withstand the processing temperature of this embodiment may be used.

Next, a base film 601 made of an insulating film such as a silicon oxide film, a silicon nitride film or a silicon oxynitride film is formed on the substrate 600. Although a two-layer structure is used as the base film 601 in this embodiment, a single-layer film of the insulating film or a structure in which two or more layers are stacked may be used. As the first layer of the base film 601, a plasma CVD method is used, and SiH ₄ , N
A silicon oxynitride film 601a formed by using H ₃ and N ₂ O as a reaction gas is formed to a thickness of 10 to 200 nm (preferably 50 to 10 nm).
0 nm).

In this embodiment, a 50 nm-thick silicon oxynitride film 601a (composition ratio: Si = 32%, O = 27%, N =
24%, H = 17%). Next, the base film 60
As the first second layer, a plasma CVD
₄ and a silicon oxynitride film 301b formed using N ₂ O as a reaction gas to a thickness of 50 to 200 nm (preferably 100 to 1 nm).
(50 nm). In this embodiment, the film thickness 1
00 nm silicon oxynitride film 301b (composition ratio Si = 32
%, O = 59%, N = 7%, H = 2%).

Next, the semiconductor layers 602 to 60 are formed on the underlying film.
5 is formed. The semiconductor layers 602 to 605 are formed by forming a semiconductor film having an amorphous structure by a known means (sputtering method, LPCV
D method or plasma CVD method)
A crystalline semiconductor film obtained by performing a known crystallization treatment (such as a laser crystallization method, a thermal crystallization method, or a thermal crystallization method using a catalyst such as nickel) is patterned and formed into a desired shape. . The thickness of the semiconductor layers 602 to 605 is 2
It is formed with a thickness of 5 to 80 nm (preferably 30 to 60 nm). The material of the crystalline semiconductor film is not limited, but is preferably silicon (silicon) or silicon germanium (S
_{i X Ge 1-X (X} = 0.0001~0.02)) may be formed such as an alloy.

In this embodiment, the plasma CVD method is used.
After forming a 55 nm amorphous silicon film, a solution containing nickel is held on the amorphous silicon film. After dehydrogenation (500 ° C., 1 hour) of this amorphous silicon film, thermal crystallization (550 ° C., 4 hours) is performed, and further, a laser annealing process for improving crystallization is performed. To form a crystalline silicon film. The crystalline silicon film is patterned by photolithography to form a semiconductor layer 60.
2 to 605 are formed.

Before or after the formation of the semiconductor layers 602 to 605, a small amount of impurity element (boron or phosphorus) may be doped in order to control the threshold value of the TFT.

When a crystalline semiconductor film is formed by a laser crystallization method, a pulse oscillation type or continuous emission type excimer laser, a YAG laser, or a YVO ₄ laser can be used. In the case of using these lasers, it is preferable to use a method in which laser light emitted from a laser oscillator is linearly condensed by an optical system and irradiated on a semiconductor film. The crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is set to 300 Hz, and the laser energy density is set to 100 to 4.
(Typically 200~300mJ / cm ²⁾ 00mJ / cm2 to.
When a YAG laser is used, it is preferable that the second harmonic is used, the pulse oscillation frequency is 30 to 300 Hz, and the laser energy density is 300 to 600 mJ / cm ² (typically 350 to 500 mJ / cm ² ). And width 100
A laser beam condensed linearly at ~ 1000 μm, for example 400 μm, is irradiated over the entire surface of the substrate, and the superposition rate (overlap rate) of the linear laser light at this time is 50-9.
What is necessary is just to set it as 0%.

Next, a gate insulating film 607 covering the semiconductor layers 602 to 605 is formed. The gate insulating film 607 is formed by a plasma CVD method or a sputtering method and has a thickness of 40 to
The insulating film containing silicon is formed to have a thickness of 150 nm. In this embodiment, a silicon oxynitride film (composition ratio: Si = 32%, O = 59%, N =
7%, H = 2%). Needless to say, the gate insulating film is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure.

When a silicon oxide film is used, TEOS (Tetraethyl Ortho Silica t
e) and O ₂ were mixed, the reaction pressure was 40 Pa, and the substrate temperature was 300.
It can be formed by discharging at a high-frequency (13.56 MHz) power density of 0.5 to 0.8 W / cm ² . The silicon oxide film thus produced is
Good characteristics as a gate insulating film can be obtained by thermal annealing at 00 to 500 ° C.

Next, as shown in FIG. 5A, a first conductive film 608 having a thickness of 20 to 100 nm and a second conductive film 60 having a thickness of 100 to 400 nm are formed on the gate insulating film 607.
9 are laminated. In this embodiment, a 30 nm-thick T
a first conductive film 608 made of an aN film and a film thickness of 370 nm
A second conductive film 609 made of a W film is formed by lamination. T
The aN film is formed by a sputtering method, and is sputtered using a Ta target in an atmosphere containing nitrogen. The W film is formed by a sputtering method using a W target. Thermal CV using tungsten hexafluoride (WF6)
It can also be formed by Method D.

In any case, in order to use the gate electrode as a gate electrode, it is necessary to lower the resistance.
It is desirable to set it to 0 μΩcm or less. The resistivity of the W film can be reduced by enlarging the crystal grains.
When there are many impurity elements such as oxygen in the film, crystallization is hindered and the resistance is increased. Therefore, in this embodiment, the W film is formed by a sputtering method using a high-purity W (purity of 99.9999%) target, and further taking care not to mix impurities from the gas phase during film formation. By forming, a resistivity of 9 to 20 μΩcm can be realized.

In this embodiment, the first conductive film 608 is used.
Is TaN and the second conductive film 609 is W. However, the present invention is not particularly limited, and any of Ta, W, Ti, Mo, Al, Cu,
It may be formed of an element selected from Cr and Nd, or an alloy material or a compound material containing the element as a main component.
Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus may be used. Also, Ag,
An alloy made of Pd and Cu may be used.

The first conductive film is formed of a tantalum (Ta) film, and the second conductive film is formed of a W film.
Is formed by a titanium nitride (TiN) film, the second conductive film is a W film, the first conductive film is formed by a tantalum nitride (TaN) film, and the second conductive film is an Al film. And the first conductive film is made of tantalum nitride (TaN).
A combination of a film and a second conductive film as a Cu film;
The first conductive film is formed of W, Mo or a film made of W and Mo, and the second conductive film is formed of Al and Si, Al and Ti, A
formed of a film comprising l and Sc or Al and Nd;
The third conductive film may be formed of Ti, TiN, or a combination of Ti and TiN.

Next, as shown in FIG.
A mask 610 made of a resist using a graphic method
613, and a first for forming electrodes and wiring.
Perform an etching process. In the first etching process, the first
And under the second etching condition. In this embodiment, the first
Etching conditions are ICP (Inductively Coupled).
Plasma: Inductively coupled plasma) etching method
CF for gas for etching _FourAnd Cl_TwoAnd O_TwoAnd use
The gas flow ratio is 25/25/10 (sccm),
500W RF (13.56M) on coil type electrode at 1Pa pressure
Hz) Apply power and generate plasma to perform etching.
U. Here, ICP manufactured by Matsushita Electric Industrial Co., Ltd. was used.
Dry etching equipment (Model E645- □ ICP)
Is used. 150W RF on substrate side (sample stage)
(13.56MHz) power on, virtually negative self-bias
Apply voltage.

The W film is etched under the first etching conditions to make the end of the first conductive layer tapered. The etching rate for W under the first etching condition is 200.39 nm / min, the etching rate for TaN is 80.32 nm / min, and the selectivity ratio of W to TaN is about 2.5. Further, the taper angle of W is about 26 ° under the first etching condition.

After that, as shown in FIG. 5B, the second etching condition is changed without removing the masks 610 to 613 made of resist, and CF ₄ and Cl ₂ are used as etching gases, respectively. Gas flow ratio 30/30 (scc
m) and 500 W of R on the coil-type electrode at a pressure of 1 Pa
F (13.56 MHz) power is applied to generate plasma and about 3
Etching is performed for about 0 seconds. Substrate side (sample stage)
Also, a 20 W RF (13.56 MHz) power is applied to apply a substantially negative self-bias voltage. Under the second etching condition in which CF ₄ and Cl ₂ are mixed, the W film and the TaN film are etched to the same extent.

The etching rate for W under the second etching condition is 58.97 nm / min, and the etching rate for TaN is 66.43 nm / min. Note that in order to perform etching without leaving a residue on the gate insulating film, the etching time is preferably increased by about 10 to 20%.

In the first etching process, by making the shape of the mask made of resist suitable,
The ends of the first conductive layer and the second conductive layer are tapered due to the effect of the bias voltage applied to the substrate side. The angle of the tapered portion may be 15 to 45 degrees. In this manner, the first shape conductive layers 615 to 618 (the first conductive layers 615 a to 618 a and the second conductive layer 615 b) including the first conductive layer and the second conductive layer are formed by the first etching process.
To 618b). Reference numeral 620 denotes a gate insulating film, and a region which is not covered with the first shape conductive layers 615 to 618 is etched by about 20 to 50 nm to form a thinned region.

Then, a first doping process is performed without removing the resist mask to add an n-type impurity element to the semiconductor layer. (FIG. 5B) The doping treatment may be performed by an ion doping method or an ion implantation method. The condition of the ion doping method is that the dose is 1 × 10 ¹³
Up to 5 × 10 ¹⁵ atoms / cm ² and an acceleration voltage of 60 to 100
Performed as keV. In this embodiment, the dose is 1.5 × 1
This is performed at 0 ¹⁵ atoms / cm ² and an acceleration voltage of 80 keV.

An element belonging to Group 15 as an impurity element imparting n-type, typically, phosphorus (P) or arsenic (As)
Here, phosphorus (P) is used. in this case,
The conductive layers 615 to 618 serve as a mask for the impurity element imparting n-type, and are self-aligned with the high concentration impurity region 62.
1 to 624 are formed. High concentration impurity regions 621-6
24 is doped with an impurity element imparting n-type in a concentration range of 1 × 10 ²⁰ to 1 × 10 ²¹ atoms / cm ³ .

Next, as shown in FIG. 5C, a second etching process is performed without removing the resist mask. The second etching process is performed under the third and fourth etching conditions. Here, as a third etching condition, CF ₄ and Cl ₂ are used as etching gases, the respective gas flow ratios are 30/30 (sccm), and 500 W of RF ( (13.56 MHz) Power is supplied to generate plasma, and etching is performed for about 60 seconds. 20W RF on substrate side (sample stage)
(13.56 MHz) Power is applied and a substantially negative self-bias voltage is applied. Under the third etching condition in which CF ₄ and Cl ₂ are mixed, the W film and the TaN film are etched to the same extent.

The etching rate for W under the third etching condition is 58.97 nm / min, and the etching rate for TaN is 66.43 nm / min. Note that in order to perform etching without leaving a residue on the gate insulating film, the etching time is preferably increased by about 10 to 20%.

Thereafter, as shown in FIG. 5C, the fourth etching condition was changed without removing the resist masks 610 to 613, and CF ₄ , Cl ₂ and O ₂ were used as etching gases. , Each gas flow ratio is 20/20/2
0 (sccm) and a pressure of 1 Pa, 5
An RF (13.56 MHz) power of 00 W is supplied to generate plasma, and etching is performed for about 20 seconds. A 20 W RF (13.56 MHz) power is also applied to the substrate side (sample stage) and a substantially negative self-bias voltage is applied.

The etching rate for TaN in the fourth etching process is 14.83 nm / min. Therefore, the W film is selectively etched. By the fourth etching process, the second conductive layers 626 to 629 (the first conductive layers 626a to 629a and the second conductive layers 626b to 626b
29b) is formed.

Next, a second doping process is performed as shown in FIG. Doping is performed on the second conductive layer 626
b to 629b are used as masks for impurity elements,
The semiconductor layer below the tapered portion in the first conductive layer is doped so that an impurity element is added. In this embodiment, P (phosphorus) is used as the impurity element, and the dose amount is 1.
5 × 10 ¹⁴ , current density 0.5 μA, acceleration voltage 90 keV
Performs plasma doping.

Thus, low concentration impurity regions 631a to 634a overlapping with the first conductive layer and low concentration impurity regions 631b to 634b not overlapping with the first conductive layer are formed in a self-aligned manner. The low concentration impurity regions 631 to 634
The concentration of phosphorus (P) added to the solution is 1 × 10 ^{17 to} 5 × 1
0 ¹⁸ atoms / cm ³ . Further, the high concentration impurity region 621
To 624 are also doped with impurity elements to form high concentration impurity regions 635 to 638.

Next, as shown in FIG. 6B, a mask made of resists (639, 640) is formed, and a third doping process is performed. By the third doping process, the impurity region 641 in which the impurity element imparting the conductivity type (p-type) opposite to the one conductivity type (n-type) is added to the semiconductor layer serving as the active layer of the p-channel TFT. , 642. First conductive layer 627a and second conductive layer 62
7b is used as a mask for the impurity element, and an impurity element imparting p-type is added to form an impurity region in a self-aligned manner.

In this embodiment, the impurity regions 641 and 642
Is formed by an ion doping method using diborane (B ₂ H ₆ ). Phosphorus is added at different concentrations to the impurity regions 641 and 642 by the first doping process and the second doping process, and the concentration of the impurity element imparting p-type is 2 × in each of the regions. 10 ²⁰ ~
By performing the doping treatment at 2 × 10 ²¹ atoms / cm ³ , there is no problem because it functions as a source region and a drain region of a p-channel TFT.

Next, a resist mask 639,
640 is removed to form a first interlayer insulating film 643 as shown in FIG. In this embodiment, as the first interlayer insulating film 643, a stacked film of a first insulating film 643a containing silicon and a second insulating film 643b made of an organic insulating material is formed.

First, the first insulating film 643a containing silicon is formed with a thickness of 100 to 200 nm by a plasma CVD method or a sputtering method using an insulating film containing silicon. In this embodiment, the film thickness is 50
A stacked film of a silicon oxynitride film with a thickness of 100 nm and a silicon nitride film with a thickness of 100 nm is formed. Needless to say, the first insulating film 643a is not limited to the above-described stacked film, and another insulating film containing silicon may be used as a single layer or a stacked structure.

Next, a step of activating the impurity element added to each semiconductor layer is performed. This activation step is performed by a thermal annealing method using a furnace annealing furnace. As a thermal annealing method, the oxygen concentration is 1 ppm or less,
Preferably in a nitrogen atmosphere of 0.1 ppm or less 400 ~
700 ° C., typically at 500-550 ° C.
In this embodiment, the activation treatment is performed by heat treatment at 550 ° C. for 4 hours. Note that, other than the thermal annealing method, a laser annealing method or a rapid thermal annealing method (RTA method) can be applied.

In this embodiment, at the same time as the activation treatment, the nickel used as a catalyst during the crystallization is doped with an impurity region (635, 637, 638) containing a high concentration of phosphorus.
And the nickel concentration in the semiconductor layer which mainly becomes a channel formation region is reduced. A TFT having a channel formation region manufactured in this manner has a low off-current value and high crystallinity, so that a high field-effect mobility can be obtained and favorable characteristics can be achieved.

The activation treatment may be performed before the formation of the first insulating film. However, when the wiring material used is weak to heat, after forming an interlayer insulating film (an insulating film containing silicon as a main component, for example, a silicon nitride film) for protecting the wiring and the like as in this embodiment, the active material is activated. It is preferable to carry out a chemical treatment.

Alternatively, a doping process may be performed after the activation process to form the first insulating film.

Further, a heat treatment is performed at 300 to 550 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% of hydrogen to hydrogenate the semiconductor layer. In this embodiment, heat treatment was performed at 410 ° C. for one hour in a nitrogen atmosphere containing about 3% of hydrogen. In this step, dangling bonds in the semiconductor layer are terminated by hydrogen contained in the interlayer insulating film. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed.

In the case where a laser annealing method is used as the activation treatment, it is desirable to irradiate a laser beam such as an excimer laser or a YAG laser after the hydrogenation.

Next, a second insulating film 643b made of an organic insulating material is formed on the first insulating film 643a. In this embodiment, an acrylic resin film having a thickness of 1.0 μm is formed.

As the organic insulating material for the second insulating film 643b, an organic resin such as polyimide, polyamide, or BCB (benzocyclobutene) can be used.

As described above, a first interlayer insulating film including the first insulating film and the second insulating film can be formed.

Next, each of the impurity regions 635, 636, 6
Patterning for forming contact holes reaching 37 and 638 is performed.

In this embodiment, since an insulating film containing silicon is formed as the first insulating film by the plasma CVD method and an insulating film made of acrylic is formed as the second insulating film, a contact hole is formed. For this, dry etching or wet etching can be used, but in this embodiment, dry etching using an RIE apparatus is performed.

First, the second insulating film is etched. At this time, CF ₄ , O _2, and He are used for the etching gas, and the respective gas flow ratios are 5/95/40 (scc).
m) and 500 W RF at the electrode at a pressure of 66.5 Pa
Turn on the power.

Next, the first insulating film is etched. At this time, the same etching gas as that for the first insulating film was used, and the flow ratio of each gas was set to 60/40/35 (s).
ccm), and the pressure of 66.5 Pa
Etching is performed by supplying RF power of W.

Then, each high-concentration impurity region 635, 63
6, 637, 638 and wiring 6 electrically connected to each other
40 to 646 and a cathode 649 are formed. In this embodiment,
After forming a film with a thickness of 500 nm using Al, this is patterned and formed. In addition to Ti and Al: Si,
l: An alloy such as Li or a stacked film of these may be used as the conductive film.

In this embodiment, since the cathode 649 is formed as a cathode, the cathode 649 is formed also as a wiring to the high-concentration impurity region 638. However, the present invention is not limited to this, and the wiring and the cathode may be separately formed of different materials.

Next, as shown in FIG. 7B, a second interlayer insulating film 650 is formed to a thickness of 1 μm, and a conductive film 651 made of a conductive material is further formed to a thickness of 10 to 10 nm (preferably, 10 to 10 nm). (10 to 50 nm).

In this embodiment, although a film made of silicon oxide is used as the second interlayer insulating film, depending on the case, in addition to an insulating film containing silicon such as silicon nitride and silicon oxynitride, polyimide, Polyamide, acrylic,
An organic resin film such as BCB (benzocyclobutene) can also be used.

[0115] As a material for forming the conductive film 651, it is preferable to use a metal material having low resistivity (also referred to as specific resistance). In this specification, a conductive material having a low resistivity has a sheet resistance of 0.01 to 1 Ω /.
The material that is □. Specifically, titanium (Ti), aluminum (Al), tantalum (Ta), tungsten (W), chromium (Cr), copper (Cu), or silver (Ag)
And the like can be used, and it is preferable that the film be formed by an evaporation method or a sputtering method.

Second interlayer insulating film 650 and conductive film 651
Is formed, an opening is formed at a position corresponding to the cathode 649 by performing a third etching process.
A bank 652 including the second interlayer insulating film 652a and the conductive film 652b is formed (FIG. 8A).

First, a mask made of a resist is formed by photolithography, and a third etching process for forming a bank is performed. Also in the third etching process, the fifth and sixth ICP etching methods are used.
The etching conditions are as follows.

In the present embodiment, as the fifth etching condition, Cl ₂ and BCl ₃ are used as the etching gas, and the respective gas flow ratios are 40/40 (sccm).
RF of 450W (13.56M) is applied to the coil type electrode at a pressure of 2Pa.
Hz) power is applied to generate plasma to perform etching, and the substrate side (sample stage) also has a 100 W RF (13.5
6MHz) Power is applied and a substantially negative self-bias voltage is applied.

Under the fifth etching condition, a part of the Al film as the conductive film can be etched.

Thereafter, the sixth etching condition was changed, CHF ₃ and Ar were used as etching gases, the respective gas flow rates were set to 30/30 (sccm), and 500 W was applied to the coil-type electrode at a pressure of 1 Pa. RF (13.56 MHz) power is applied to generate plasma and perform etching for about 30 seconds. 20W RF (1) on the substrate side (sample stage)
3.56MHz) Power is applied and a substantially negative self-bias voltage is applied. Thereby, a part of the second interlayer insulating film is etched.

As described above, as shown in FIG.
Of the interlayer insulating film 652a and the conductive film 652b are formed.

Next, as shown in FIG.
An organic compound layer 654 is formed thereover by an evaporation method. Here, it is shown that one kind of the organic compound layer formed by the organic compound which emits three kinds of light of red, green and blue is formed in this embodiment. The combination of the organic compounds will be described in detail below.

First, an organic compound layer that emits red light is formed. The red-emitting organic compound layer in this example is formed of an organic compound having an electron transporting property, an organic compound having a blocking property, an organic compound having a light emitting property, a host material, an organic compound having a hole transporting property and an organic compound having a hole injecting property. It is formed.

Specifically, tris (8-quinolinolato) aluminum (hereinafter, referred to as an organic compound having an electron transporting property)
Alq ₃ is formed to a thickness of 25 nm, and bathocuproin (hereinafter, referred to as an organic compound having blocking properties) is formed.
BCP) is formed to a thickness of 8 nm, and 2,3,7,8,12,13,17,1
8-octaethyl-21H, 23H-porphyrin-platinum (hereinafter, referred to as PtOEP) together with 4,4'-dicarbazole-biphenyl (hereinafter, referred to as CBP) which is an organic compound (hereinafter, referred to as a host material) serving as a host A film having a thickness of 25 to 40 nm is formed by co-evaporation, and 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (hereinafter referred to as an organic compound having a hole transporting property) is used. ,
α-NPD) is formed into a film having a thickness of 40 nm, and copper phthalocyanine (hereinafter referred to as C), which is an organic compound capable of injecting holes, is formed.
(shown as u-Pc) to a thickness of 15 nm, whereby a red-emitting organic compound layer can be formed.

Here, the case where the organic compound layer emitting red light is formed using six kinds of organic compounds having different functions has been described. However, the present invention is not limited to this, and the organic compound layer emitting red light can be used. Known materials can be used as the compound.

Next, an organic compound layer which emits green light is formed. The organic compound layer emitting green light in this embodiment is an organic compound having an electron transporting property, an organic compound having a blocking property,
It is formed from a light-emitting organic compound, a host material, a hole-transporting organic compound, and a hole-injecting organic compound.

More specifically, an electron-transporting organic compound, Alq ₃ , is formed to a thickness of 40 nm, and a blocking organic compound, BCP, is formed to a thickness of 10 nm. Tris (2-phenylpyridine) which is a luminescent organic compound using CBP as a transporting host material
A film is formed in a thickness of 5 to 40 nm by co-evaporation with iridium (Ir (ppy) ₃ ), and a film of α-NPD, which is an organic compound having a hole transporting property, is formed in a thickness of 10 nm.
MTDATA which is an organic compound having a hole transporting property
m, and a hole-injecting organic compound, C
A green light-emitting organic compound can be formed by forming u-Pc to a thickness of 10 nm.

Here, the case where the organic compound layer emitting green light is formed using seven kinds of organic compounds having different functions has been described. However, the present invention is not limited to this. Known materials can be used as the compound.

Next, an organic compound layer which emits blue light is formed. The organic compound layer emitting blue light in this example is an organic compound having an electron transporting property, an organic compound having a blocking property,
It is formed from a light-emitting organic compound and a hole-injecting organic compound.

Specifically, an electron transporting organic compound, Alq _3, was formed to a thickness of 40 nm, and a blocking organic compound, BCP, was formed to a thickness of 10 nm. Α-NPD which is an organic compound of 40 nm
Is a hole injecting organic compound, Cu
By forming -Pc to a thickness of 20 nm, an organic compound layer emitting blue light can be formed.

Although the case where the organic compound layer emitting blue light is formed using four kinds of organic compounds having different functions has been described above, the present invention is not limited to this, and the organic compound layer emitting blue light can be used. Known materials can be used as the compound.

By forming the organic compound described above on the cathode, an organic compound layer which emits red, green and blue light can be formed in the pixel portion.

Next, the organic compound layer 654 and the bank 65
2, an anode 655 made of a transparent conductive film is formed. In this embodiment, an indium tin oxide (ITO) film or a transparent conductive film obtained by mixing 2 to 20% of zinc oxide (ZnO) with indium oxide is used as a transparent electrode for 80 to 120 n.
m to be used. In this embodiment, another known material can be used as long as it is a transparent conductive film as the anode 655 of the light emitting element.

Note that the ITO film can be formed by using an evaporation method. In this embodiment, a case in which an ion plating method is used is particularly described.

The ion plating method is one of gas phase surface treatment techniques classified as a vapor deposition method. A substrate to be vaporized is ionized or excited by a high-frequency plasma or vacuum discharge to deposit a vapor-deposited substance by any method. Is applied to the substrate by applying a negative potential to the ions to accelerate the ions.

As a specific condition for forming the anode by using the ion plating method, the substrate temperature is set to 100 to 300 in an inert gas atmosphere of 0.01 to 1 Pa.
It is desirable to carry out vapor deposition while keeping the temperature at ° C. It is desirable to use ITO as an evaporation source having a sintering density of 70% or more. The optimum conditions for using the ion plating method can be appropriately selected by a practitioner.

By ionizing or exciting the deposition material using high-frequency plasma, the rate of ionization or excitation of the deposition material can be increased, and the ionized or excited deposition material is in a high energy state. Therefore, it is possible to sufficiently bond with oxygen while maintaining a high evaporation rate. Therefore, a high-quality film can be formed at a high speed.

The method of forming the anode 655 of this embodiment is as follows.
It is not limited to the ion plating method described above. However, a film formed by using the ion plating method has a high adhesion and has a high crystallinity even at a relatively low temperature.
Since an O film can be formed, the resistance of ITO can be reduced, and a uniform film can be formed over a relatively large area, which is suitable for increasing the size of a substrate.

Thus, as shown in FIG. 8B, the cathode 649 electrically connected to the current controlling TFT 704,
A bank 652 formed in the gap between the cathodes;
2 and the organic compound layer 654 formed on the cathode 649
Thus, an element substrate of a light emitting device including the organic compound layer 654 and the anode formed over the bank 652 can be formed. In the manufacturing process of the light emitting device in this embodiment, a source signal line is formed using a material for forming a gate electrode, and a source and a drain electrode are formed due to a relationship between a circuit configuration and a process. Although the gate signal lines are formed using a wiring material, different materials can be used.

Further, a driver circuit 705 having an n-channel TFT 701 and a p-channel TFT 702 and a pixel portion 706 having a switching TFT 703 and a current control TFT 704 can be formed over the same substrate.

The n-channel TFT 70 of the drive circuit 705
Reference numeral 1 denotes a low-concentration impurity region 6 overlapping the channel formation region 501 and the first conductive layer 626a forming a part of the gate electrode.
31 (GOLD region) and a high-concentration impurity region 635 functioning as a source region or a drain region.
The channel formation region 50 is provided in the p-channel TFT 702.
2. It has impurity regions 641 and 642 functioning as a source region or a drain region.

The switching TFT 70 of the pixel portion 706
3 includes a channel formation region 503 and a low-concentration impurity region 633 overlapping with the first conductive layer 628a for forming a gate electrode.
a (LDD region), a low-concentration impurity region 633b (LDD region) which does not overlap with the first conductive layer 628a, and a high-concentration impurity region 637 functioning as a source or drain region.

The current controlling TFT 704 of the pixel portion 706 has a channel forming region 504 and a first forming a gate electrode.
Low-concentration impurity region 634a overlapping conductive layer 629a of FIG.
(LDD region), a low-concentration impurity region 634b (LDD region) which does not overlap with the first conductive layer 628a, and a high-concentration impurity region 6 functioning as a source region or a drain region.
38.

In this embodiment, although the erasing TFT is not shown, it is formed in the same manner as the current controlling TFT.
It has a similar structure.

In this embodiment, the driving voltage of the TFT is 1.2 to 10 V, preferably 2.5 to 10 V.
5.5V.

When the display of the pixel portion is operating (in the case of displaying a moving image), the background display is performed by the pixels emitting the light emitting elements, and the character display is performed by the pixels where the light emitting elements do not emit light. However, in the case where the moving image display of the pixel portion is stationary for a certain period of time or more (referred to as a standby state in this specification), the display method is switched (inverted) to save power. It is good to keep it.
Specifically, characters are displayed by pixels in which the light emitting element emits light (also referred to as character display), and the background is displayed by pixels in which the light emitting element does not emit light (also referred to as background display).

FIG. 9 is a top view of an element substrate in which light emitting elements are formed on a substrate (element substrate) as described above.

[0148] A state in which a pixel portion 706, a gate signal line driver circuit 901, a source signal line driver circuit 902, and a terminal 903 are formed on a substrate 600 is shown. The terminal 903 is connected to each drive circuit, a current supply line formed in a pixel portion, and an anode by a lead wiring 904.

Further, an IC chip on which a CPU, a memory, and the like are formed as necessary may be mounted on the element substrate by a COG (Chip on Glass) method or the like.

Note that the light emitting element 656 is formed between the second interlayer insulating film 650 and the bank 652 including the conductive film 651. First, a cathode 649 is formed, and an organic compound layer 654 is formed thereon. Then, an anode 655 is formed over the entire pixel portion so as to cover the plurality of organic compound layers 654 and the banks 652. Note that, at this time, the anode 655 is formed to be in contact with the conductive film 653.

The wiring 904 is formed in the same layer as the gate signal line (not shown), and is not in direct contact with the conductive film 653. Then, the routing wiring 904 and the anode 6
Reference numeral 55 designates a contact at a portion where the anode 655 is formed on the routing wiring 904 so as to overlap.

[Embodiment 2] Next, a method of completing the element substrate shown in FIG. 9 as a light emitting device will be described with reference to FIG.

FIG. 10A is a top view showing a light emitting device.
FIG. 10B is a cross-sectional view taken along line AA ′ of FIG. 1001 shown by a dotted line is a source signal line driving circuit, 1002 is a pixel portion, and 1003 is a gate signal line driving circuit. 1004 is a cover material, 1005 is a sealant, and the inside surrounded by the sealant 1005 is a space.

Incidentally, reference numeral 1008 denotes a source signal line driving circuit 1
001 and a wiring for transmitting a signal input to the gate signal line driver circuit 1003, and receives a video signal and a clock signal from an FPC (flexible print circuit) 1009 serving as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC.
The light-emitting device in this specification includes not only the light-emitting device main body but also a state in which an FPC or a PWB is attached thereto.

Next, the sectional structure will be described with reference to FIG. The pixel portion 100 is provided above the substrate 1010.
2, a source signal line driving circuit 1001 is formed;
The pixel portion 1002 is formed by a plurality of pixels including a current control TFT 1011 and a cathode 1012 electrically connected to a drain thereof. Also, the source signal line driving circuit 10
01 is an n-channel TFT 1013 and a p-channel TF
CMOS circuit combined with T1014 (see FIG. 8)
It is formed by using.

The cathode 1012 functions as a cathode of the light emitting element. Banks 1015 are formed at both ends of the cathode 1012, and an organic compound layer 1016 is formed on the cathode 1012. In the present invention, the bank 1015
Is formed by stacking an insulating film 1015a and a conductive film 1015b. Further, an anode 1017 of a light emitting element is formed over the bank 1015 and the organic compound layer 1016.

The anode 1017 also functions as a common wiring for all pixels, and is electrically connected to the FPC 1009 via the wiring 1008.

Further, the cover material 1 was
004 is attached. The cover material 1004
A spacer made of a resin film may be provided to secure an interval between the light emitting element and the light emitting element. The space 1007 inside the sealant 1005 is filled with an inert gas such as nitrogen. Note that an epoxy resin is preferably used as the sealant 1005. Further, it is preferable that the sealant 1005 be a material that does not transmit moisture and oxygen as much as possible. Further, a substance having a moisture absorbing effect or a substance having an effect of preventing oxidation may be contained in the space 1007.

In this embodiment, as a material for forming the cover member 1004, in addition to a glass substrate and a quartz substrate, FRP
(Fiberglass-Reinforced Plastics), a plastic substrate made of PVF (polyvinyl fluoride), mylar, polyester, acrylic, or the like can be used.

Further, after the cover material 1004 is bonded using the sealant 1005, it is also possible to seal with a sealant so as to further cover the side surface (exposed surface).

As described above, the light emitting element is placed in the space 1007.
The light-emitting element can be completely shut off from the outside by encapsulating the organic compound layer, and a substance such as moisture or oxygen, which promotes deterioration of the organic compound layer, can be prevented from entering from the outside. Therefore, a highly reliable light-emitting device can be obtained.

The structure of this embodiment can be implemented by freely combining with any structure of the first embodiment.

[Embodiment 3] FIG. 11A shows a detailed top structure of a pixel, and FIG. 11B shows a circuit diagram. Figure 1
In 1, the switching TFT provided on the substrate
1100 is a switching (n-channel type) TF shown in FIG.
It is formed using T701. Therefore, for the description of the structure, the description of the switching (n-channel) TFT 701 may be referred to. The wiring denoted by 1102 is a gate electrode 1101 (11
01a and 1101b).

Although the present embodiment has a double gate structure in which two channel forming regions are formed, a single gate structure in which one channel forming region is formed or a triple gate structure in which three channel forming regions are formed. good.

The source of the switching TFT 1100 is connected to the source wiring 1103, and the drain is connected to the drain wiring 1104. Also, the drain wiring 1
104 is a gate electrode 110 of the current controlling TFT 1105
6 is electrically connected. The current controlling TFT 11
05 is a current control (n-channel type) TFT 704 shown in FIG.
It is formed by using. Therefore, for the description of the structure, the description of the current control (n-channel type) TFT 704 may be referred to. Although the present embodiment has a single gate structure, it may have a double gate structure or a triple gate structure.

The source of the current control TFT 1105 is electrically connected to the current supply line 1107, and the drain is electrically connected to the drain wiring 1108. Further, the drain wiring 1108 is electrically connected to a cathode 1109 shown by a dotted line.

The wiring denoted by reference numeral 1110 is a gate wiring electrically connected to the gate electrode 1112 of the erasing TFT 1111. Note that the source of the erasing TFT 1111 is electrically connected to the current supply line 1107, and the drain is electrically connected to the drain wiring 1104.

The erasing TFT 1111 is formed in the same manner as the current controlling (n-channel type) TFT 704 in FIG. Therefore, for the description of the structure, the description of the current control (n-channel type) TFT 704 may be referred to. Although the present embodiment has a single gate structure, it may have a double gate structure or a triple gate structure.

A storage capacitor (capacitor) is formed in a region indicated by reference numeral 1113. Capacitor 1113
Is a semiconductor film 1114 electrically connected to the current supply line 1107, and an insulating film (not shown) in the same layer as the gate insulating film
And the gate electrode 1106. In addition, a capacitor formed by the gate electrode 1106, the same layer (not shown) as the first interlayer insulating film, and the current supply line 1107 can be used as a storage capacitor.

The light emitting element 1115 shown in the circuit diagram of FIG. 11B has a cathode 1109, an organic compound layer (not shown) formed on the cathode 1109, and an anode (not shown) formed on the organic compound layer. (Not shown)). In the present invention,
The cathode 1109 is connected to the source region or the drain region of the current controlling TFT 1105.

A counter potential is applied to the anode of the light emitting element 1115. The power supply potential is applied to the current supply line V. The potential difference between the counter potential and the power supply potential is always kept at such a level that the light emitting element emits light when the power supply potential is applied to the cathode. The power supply potential and the counter potential are provided to the light emitting device of the present invention by a power supply provided by an external IC or the like. The power supply for giving the opposite potential is
In this specification, it is particularly referred to as a counter power supply 1116.

The structure of this embodiment can be implemented by freely combining with any of the structures of the first and second embodiments.

[Embodiment 4] In this embodiment, a method for manufacturing a light emitting element having a structure different from that shown in Embodiment 1 will be described with reference to FIGS. Note that the steps up to the production of the cathode 649 in FIG.

As shown in FIG. 12A, a second interlayer insulating film 1201 made of acrylic is formed on the cathode 649 by 1 μm.
To a thickness of

In this embodiment, acrylic is used for the second interlayer insulating film 1201. In some cases, in addition to organic resins such as polyimide, polyamide, and BCB (benzocyclobutene), silicon oxide and nitride are used. An inorganic material containing silicon such as silicon and silicon oxynitride can also be used.

After the second interlayer insulating film 1201 is formed, an opening is formed at a position corresponding to the cathode 649 by etching.

In this case, a dry etching method such as an ICP etching method or a RIE (reactive ion etching) method or a wet etching method can be used for etching, but in this embodiment, an RIE apparatus is used. Perform dry etching.

Using CF ₄ , O _2, and He as the etching gas, the respective gas flow rates were 5/95/40 (sc).
cm) and 500 W of R at the electrode at a pressure of 66.5 Pa.
Apply F power. As a result, the second interlayer insulating film formed on the cathode can be etched, and the bank 12 can be etched.
03 can be formed.

Next, an organic compound layer 1202 is formed in the opening of the second interlayer insulating film by using an evaporation method. Note that in this embodiment, an organic compound layer formed of an organic compound which emits three kinds of light of red, green, and blue is formed, so that a film is formed for each different organic compound layer using a metal mask. FIG. 12B shows one of the three types of organic compound layers.
Although the manner in which the types are formed is shown, three types of organic compound layers are formed. Note that the organic compound layer described in Embodiment 1 can be used for the organic compound layer formed in this embodiment.

Next, as shown in FIG. 13A, a conductive film 1204 is formed so as to cover the second interlayer insulating film in the pixel portion and a part of the organic compound layer.

[0181] As a metal material for forming the conductive film 1204, a metal material having low resistivity (also referred to as specific resistance) is preferably used. In this specification, a conductive material having a low resistivity has a sheet resistance of 0.01 to 1 Ω /.
The material that is □. Specifically, titanium (Ti), aluminum (Al), tantalum (Ta), tungsten (W), chromium (Cr), copper (Cu), or silver (Ag)
Etc. can be used.

It is preferable that the conductive film 1204 be formed by an evaporation method or a sputtering method using a metal mask so as not to be formed in a portion where the cathode 649 and the organic compound layer are stacked. The thickness is 3
The thickness may be 0 to 100 nm (preferably 40 to 80 nm).

Further, after the conductive film 1204 is formed, the anode 1205 is formed by an evaporation method. Note that as other methods for forming the anode, an ion plating method or a sputtering method can be used. As the anode 1205, a transparent conductive film is formed with a thickness of 80 to 120 nm.

In this embodiment, as the anode 1205, an indium tin oxide (ITO) film or a transparent conductive film in which 2 to 20% of zinc oxide (ZnO) is mixed with indium oxide is used. In this embodiment, the anode 120 of the light emitting element is used.
Other known materials can be used as long as the conductive film 5 is a transparent conductive film.

As described above, the light emitting device of the present invention can be formed. Note that the light emitting device of this embodiment can have the sealing structure of Embodiment 2 and can be implemented with the circuit configuration shown in Embodiment 3.

[Embodiment 5] Since a light emitting device using a light emitting element is a self-luminous type, it has better visibility in a bright place and a wider viewing angle than a liquid crystal display device. Therefore, it can be used for display portions of various electric appliances.

Electric appliances using the light emitting device manufactured according to the present invention include a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproducing device (car audio, audio component, etc.), a notebook type personal computer. Computers, game consoles, personal digital assistants (mobile computers, mobile phones, portable game consoles, electronic books, etc.),
An image reproducing device provided with a recording medium (specifically, a device provided with a display device capable of reproducing a recording medium such as a digital video disk (DVD) and displaying the image) is provided. In particular, in a portable information terminal in which a screen is often viewed from an oblique direction, since a wide viewing angle is regarded as important, it is preferable to use a light emitting device having a light emitting element. FIG. 14 shows specific examples of these electric appliances.

FIG. 14A shows a display device,
01, a support base 2002, a display unit 2003, a speaker unit 2004, a video input terminal 2005, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2003. Since a light-emitting device having a light-emitting element is a self-luminous type, it does not require a backlight and can have a thinner display portion than a liquid crystal display device. The display device includes all information display devices for personal computers, TV broadcast reception, advertisement display, and the like.

FIG. 14B shows a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103,
An operation key 2104, an external connection port 2105, a shutter 2106, and the like are included. The light-emitting device manufactured according to the present invention can be used for the display portion 2102.

FIG. 14C shows a notebook personal computer, which includes a main body 2201, a housing 2202, and a display section 2.
203, keyboard 2204, external connection port 220
5, including a pointing mouse 2206 and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2203.

FIG. 14D shows a mobile computer, which includes a main body 2301, a display portion 2302, and a switch 230.
3, an operation key 2304, an infrared port 2305, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2302.

FIG. 14E shows a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, and includes a main body 2401, a housing 2402, a display portion A 2403, a display portion B 2404, a recording medium ( DVD, etc.) reading unit 240
5, operation keys 2406, a speaker unit 2407, and the like. The display portion A2403 mainly displays image information and the display portion B2404 mainly displays character information. The light-emitting device manufactured according to the present invention employs these display portions A and B240.
3, 2404. Note that the image reproducing device provided with the recording medium includes a home game machine and the like.

FIG. 14F shows a goggle-type display (head-mounted display).
1, including a display unit 2502 and an arm unit 2503. The light-emitting device manufactured according to the present invention can be used for the display portion 2502.

FIG. 14G) shows a video camera,
Reference numeral 601, display unit 2602, housing 2603, external connection port 2604, remote control receiving unit 2605, image receiving unit 260
6, a battery 2607, a voice input unit 2608, operation keys 2609, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2602.

FIG. 14H shows a mobile phone, which includes a main body 2701, a housing 2702, a display portion 2703, a voice input portion 2704, a voice output portion 2705, operation keys 2706,
An external connection port 2707, an antenna 2708, and the like are included.
The light-emitting device manufactured according to the present invention can be used for the display portion 2703. Note that the display portion 2703 displays white characters on a black background, so that power consumption of the mobile phone can be suppressed.

If the emission luminance of the organic material is increased in the future, the light including the output image information can be enlarged and projected by a lens or the like and used for a front-type or rear-type projector.

[0197] The above-mentioned electric appliances are available on the Internet or C
Information distributed through an electronic communication line such as an ATV (cable television) is frequently displayed, and in particular, opportunities to display moving image information are increasing. Since the response speed of the organic material is extremely high, the light-emitting device is preferable for displaying moving images.

In the light emitting device, since the light emitting portion consumes power, it is preferable to display information so that the light emitting portion is reduced as much as possible. Therefore, when a light emitting device is used for a portable information terminal, particularly a display portion mainly for character information such as a mobile phone or a sound reproducing device, the light emitting portion is driven to form character information with a non-light emitting portion as a background. Is preferred.

As described above, the application range of the light emitting device manufactured according to the present invention is extremely wide, and it can be used for electric appliances in various fields. Further, in the electric appliance of this embodiment, the light emitting devices manufactured in Embodiments 1 to 4 can be used for the display portion.

[0200]

According to the present invention, the average film resistance of the anode can be reduced by the conductive film provided in contact with the anode. Thus, the in-plane potential distribution at the anode can be made uniform, and the luminance of the light-emitting element can be made uniform, so that a light-emitting device that displays clearer images can be obtained. In addition, by using the light-emitting device of the present invention as a display portion, an electric appliance with high visibility can be obtained.

[Brief description of the drawings]

FIG. 1 illustrates a light-emitting element of the present invention.

FIG. 2 is a top block diagram of the light emitting device of the present invention.

FIG. 3 illustrates a pixel portion of a light-emitting device of the present invention.

FIG. 4 is a diagram illustrating a pixel portion of a light emitting device of the present invention.

FIG. 5 illustrates a manufacturing process of a light-emitting device of the present invention.

FIG. 6 illustrates a manufacturing process of a light-emitting device of the present invention.

FIG. 7 illustrates a manufacturing process of a light-emitting device of the present invention.

FIG. 8 illustrates a manufacturing process of a light-emitting device of the present invention.

FIG. 9 illustrates an element substrate of a light emitting device of the present invention.

FIG. 10 illustrates a sealing structure of a light emitting device of the present invention.

FIG. 11 is a top view of a pixel of a light emitting device of the present invention.

FIG. 12 illustrates a manufacturing process of a light-emitting device of the present invention.

FIG. 13 illustrates a manufacturing process of a light-emitting device of the present invention.

FIG. 14 is a diagram of an electric appliance using the light-emitting device of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/10 H05B 33/14 A 33/12 H01L 29/78 612Z 33/14 F-term (Reference) 3K007 AB02 AB05 BA06 BB07 CA03 CB01 DA02 EB00 FA01 5C094 AA02 AA21 BA03 BA27 CA19 CA24 DA15 EA04 EA05 EA07 EB05 5F110 AA30 BB02 CC02 DD01 DD02 DD03 DD13 DD14 DD15 DD17 EE01 EE02 EE03 EE04 FF23 FF23 FF23 FF23 GG32 GG35 GG43 GG45 GG47 HJ01 HJ04 HJ12 HJ13 HJ18 HJ23 HL03 HL05 HL06 HM15 NN03 NN22 NN24 NN27 NN35 NN72 NN73 PP01 PP03 PP05 PP06 PP10 PP34 QQ11 QQ24 QQ25 QQ28

Claims (35)

[Claims] A TFT formed on an insulating surface;
A plurality of cathodes electrically connected to the FT; a bank formed between the cathodes; an organic compound layer formed on the cathode; and an anode formed on the organic compound layer and the bank. Wherein the bank comprises:
A light-emitting device comprising an insulating film and a conductive film, wherein the light-emitting device has a structure in which the conductive film is stacked over the insulating film. 2. A TFT formed on an insulating surface;
A cathode electrically connected to the FT; a bank formed in contact with an end of the cathode; an organic compound layer formed on the cathode; and an anode formed on the bank and the organic compound layer And wherein the bank has a structure in which a conductive film is stacked on an insulating film. 3. The light emitting device according to claim 1, wherein the anode formed on the organic compound layer and the bank is formed of the same film. 4. A TFT formed on an insulating surface;
A plurality of cathodes electrically connected to the FT; an insulating film formed between the plurality of cathodes; a conductive film formed on the insulating film; and an organic compound layer formed on the cathode. A light emitting device comprising: an anode formed on the conductive film and the organic compound layer. 5. The light emitting device according to claim 1, wherein said anode is made of a transparent conductive film. 6. The light emitting device according to claim 1, wherein said insulating film is made of an inorganic material. 7. The light emitting device according to claim 6, wherein said inorganic material is made of silicon oxide, silicon nitride, and silicon oxynitride. 8. The conductive film according to claim 1, wherein the conductive film has a sheet resistance of 0.01 to 1 Ω /.
A light-emitting device comprising a conductive material of □. 9. The light emitting device according to claim 1, wherein the conductive film is made of titanium, aluminum, tantalum, tungsten, chromium, copper, silver, or an alloy containing these. A light-emitting device characterized by the above-mentioned. 10. A TFT formed on an insulating surface, a plurality of cathodes electrically connected to the TFT, a bank of an insulating film formed between the cathodes, and a bank formed on the cathode. A light-emitting device comprising: an organic compound layer; a conductive film formed on the bank; and an anode formed on the organic compound layer and the conductive film. 11. A TFT formed on an insulating surface, a plurality of cathodes electrically connected to the TFT, an insulating film formed between the plurality of cathodes, and an organic film formed on the cathode. A compound layer, a conductive film formed on the insulating film,
A light emitting device comprising: an anode formed on the conductive film and the organic compound layer. 12. The light emitting device according to claim 10, wherein said organic compound layer and said anode formed on said conductive film are made of the same film. 13. A light emitting device according to claim 10, wherein said anode is made of a transparent conductive film. 14. The light emitting device according to claim 10, wherein the insulating film is made of an inorganic material. 15. The light emitting device according to claim 14, wherein
The light emitting device according to claim 1, wherein the inorganic material includes silicon oxide, silicon nitride, and silicon oxynitride. 16. The conductive film according to claim 10, wherein the conductive film has a sheet resistance of 0.01 to 0.01.
A light-emitting device comprising a conductive material of 1 Ω / □. 17. The light emitting device according to claim 10, wherein the conductive film is made of titanium,
Aluminum, tantalum, tungsten, chromium, copper,
A light-emitting device comprising silver or an alloy containing these. 18. An electric appliance using the light emitting device according to claim 1. Description: 19. A method for forming a TFT on an insulating surface, comprising:
Forming a plurality of cathodes electrically connected to T, forming a bank between the plurality of cathodes, forming an organic compound layer on the cathode, forming an anode on the organic compound layer and on the bank; A method for manufacturing a light-emitting device to be formed, wherein the bank is formed by stacking a conductive film on an insulating film. 20. forming a TFT on an insulating surface;
Forming a cathode electrically connected to T; forming a bank in contact with an end of the cathode; forming an organic compound layer on the cathode; and forming an anode on the bank and the organic compound layer A light emitting device manufacturing method, wherein the bank comprises:
A method for manufacturing a light-emitting device, comprising forming a conductive film over an insulating film. 21. The method according to claim 19, wherein
The method for manufacturing a light-emitting device, wherein the anode is formed of the same film on the organic compound layer and the bank. 22. A method of forming a TFT on an insulating surface, comprising:
Forming a plurality of cathodes electrically connected to T, forming an insulating film between the plurality of cathodes, forming a conductive film on the insulating film, forming an organic compound layer on the cathode, A method for manufacturing a light-emitting device, comprising forming an anode over a conductive film and over the organic compound layer. 23. The method for manufacturing a light emitting device according to claim 19, wherein the anode is formed of a transparent conductive film. 24. The method for manufacturing a light-emitting device according to claim 19, wherein the insulating film is formed of an inorganic material. 25. The method according to claim 24, wherein the inorganic material comprises:
A method for manufacturing a light-emitting device, which includes silicon oxide, silicon nitride, and silicon oxynitride. 26. The conductive film according to claim 19, wherein the conductive film has a sheet resistance of 0.01 to 1.
A method for manufacturing a light-emitting device, which is a conductive material of Ω / □. 27. The light-emitting device according to claim 19, wherein the conductive film is made of titanium, aluminum, tantalum, tungsten, chromium, copper, silver, or an alloy containing these. Method for manufacturing the device. 28. A method of forming a TFT on an insulating surface, comprising:
Forming a plurality of cathodes electrically connected to T; forming a bank between the plurality of cathodes; forming an organic compound layer on the cathode; forming a conductive film on the bank; A method for manufacturing a light-emitting device, comprising forming an anode over a layer and over the conductive film. 29. forming a TFT on an insulating surface,
Forming a plurality of cathodes electrically connected to T, forming an insulating film between the plurality of cathodes, forming an organic compound layer on the cathode, forming a conductive film on the insulating film, A method for manufacturing a light-emitting device, wherein an anode is formed over an organic compound layer and the conductive film. 30. The method according to claim 28 or 29,
A method for manufacturing a light-emitting device, wherein the anode is formed of the same film. 31. The method for manufacturing a light emitting device according to claim 28, wherein the anode is formed of a transparent conductive film. 32. The method for manufacturing a light-emitting device according to claim 28, wherein the insulating film is made of an inorganic material. 33. The method according to claim 32, wherein the inorganic material comprises:
A method for manufacturing a light-emitting device, comprising silicon oxide, silicon nitride, and silicon oxynitride. 34. The conductive film according to claim 28, wherein the conductive film has a sheet resistance of 0.01 to 1.
A method for manufacturing a light-emitting device, which is a conductive material of Ω / □. 35. The light-emitting device according to claim 28, wherein the conductive film is made of titanium, aluminum, tantalum, tungsten, chromium, copper, silver, or an alloy containing these. Method for manufacturing the device.