KR20100051499A - Method for fabricating flexible display device - Google Patents

Abstract

PURPOSE: A method for manufacturing flexible display device is provided to reduce a manufacturing process through technology of returning dissolution substrate carrier, thereby securing the productivity. CONSTITUTION: A carrier substrate(100) is provided. A dissolution coating film(101) is formed by using dissolution polymer material in the carrier substrate. A display device layer is formed on the dissolution coating film. The dissolution coating film is hardened. The carrier substrate is removed. The dissolution coating film is formed in a spin coating, a silt coating or mixed way of the spin coating and the silt coating. The dissolution polymer material is a material that has high temperature thermal resistance characteristic like a polyimide, a silicone resin, or acryl.

Description

Flexible display device manufacturing method {Method for fabricating flexible display device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible display device, and more particularly, a flexible display capable of securing mass productivity of a flexible product by applying a soluble substrate carrier transport technology by a method of transporting a flexible substrate such as a plastic substrate. It relates to a device manufacturing method.

A general display device is an image display device using a phenomenon in which colloidal particles are moved to either polarity when a pair of electrodes applied with a voltage is immersed in a colloidal solution. It is expected to be spotlighted as an electric paper because it has characteristics such as electric power.

A display device such as an electric paper has a structure in which an electrophoretic body is interposed between two electrodes, and at least one of the two electrodes needs to be transparent to display an image. When an electric potential is applied across these electrodes, the charged particles in the electrophoretic body move to one electrode or the other, whereby the image can be viewed through a viewing sheet or an opposite electrode.

In addition, the display device such as the electric paper must be flexible, and in order to implement such a flexible display device, a flexible substrate such as a plastic substrate or a thin metal foil must be used.

Conventionally, in order to implement a flexible display device, a technique of attaching a flexible substrate to a glass substrate has been proposed.

A method of manufacturing a flexible display device according to the related art, in which a flexible substrate is attached to a glass substrate as described above, will be described below with reference to FIGS. 1A to 1D.

1A to 1D are cross-sectional views illustrating a method of manufacturing a flexible display device according to the related art.

As shown in Fig. 1A, a flexible plastic substrate 11 is prepared, and before the device fabrication process is performed on the plastic substrate 11, the plastic substrate 11 has a thin thickness. It has a characteristic that is easy to bend, but when the plastic substrate 11 is seated on the table to perform the manufacturing process is bent state. At this time, if the plastic 11 is placed in the 휜 state, it becomes difficult to perform the manufacturing process. In addition, the plastic substrate 11 is supplied in a roll type, and has a thickness of about 100 μm or more.

Therefore, as shown in Figure 1b, in order to prevent this problem, after preparing a rigid substrate (rigid substrate) 10 made of a material such as glass as a carrier substrate on the plastic substrate (10) 11) is adhered using the adhesive (31).

Then, the fixed substrate 10 to which the plastic substrate 11 is attached is loaded into the manufacturing process chamber through a substrate transport system (not shown) to perform the device manufacturing process on the plastic substrate 11.

In this case, the device manufacturing process performed on the plastic substrate 11 will be described with reference to FIG. 1C.

As illustrated in FIG. 1C, a metal material is deposited on a plastic substrate 11 adhered to the fixed substrate 10, and then selectively patterned by a mask process to form a gate electrode 13.

Next, a gate insulating film 15 made of silicon nitride (SiNx) or the like is formed on the lower substrate 11 including the gate electrode 13.

Subsequently, a semiconductor layer 17 including a hydrogenated amorphous silicon layer or the like is formed on the gate insulating layer 15, and an n + silicon layer doped with a high concentration of n + impurities on the surface of the semiconductor layer 17. (19) is formed. In this case, the n + silicon layer 19 is used as an ohmic contact layer of the thin film transistor.

Subsequently, the n + silicon layer 19 and the semiconductor layer 17 are selectively patterned by a mask process.

Next, a metal material is deposited on the gate insulating layer 15 including the selectively patterned n + silicon layer 19 and the semiconductor layer 17, and then selectively patterned by a mask process to form a source electrode 21. And the drain electrode 23 spaced apart from the source electrode 21 by the channel length, respectively. In this case, a portion of the n + silicon layer 19 positioned between the source electrode 21 and the drain electrode 23 is exposed to the outside.

In this way, the source electrode 21 and the drain electrode 23 together with the semiconductor layer 17 and the gate electrode 13 below form a thin film transistor which is a switching element.

In addition, a channel of the thin film transistor is formed in the semiconductor layer 17 between the source electrode 21 and the drain electrode 23.

Subsequently, the exposed n + silicon layer 19 is removed by performing a dry etching process using the source electrode 21 and the drain electrode 23 as a blocking film.

Next, an organic material having excellent planarization characteristics and photosensitivity on the lower substrate 11 including the source electrode 21 and the drain electrode 23, an insulating material having a low dielectric constant, or an inorganic material, silicon nitride, or the like. A protective film 25 is formed.

Subsequently, the protective layer 25 is selectively patterned by a mask process to form a contact hole (not shown) in the protective layer 25 to expose a part of the drain electrode 23.

Next, a metal layer (not shown) made of a transparent conductive material such as ITO or IZO is deposited on the passivation layer 25 including the contact hole (not shown), and then selectively removed by a mask process to form a pixel electrode ( 29).

In this way, the process of manufacturing a thin film transistor array on the plastic substrate 11 is completed.

Subsequently, as shown in FIG. 1D, after the process of manufacturing the thin film transistor array is completed, the plastic substrate 11 is unloaded with the fixed substrate 10 to which the plastic substrate 11 is adhered by a substrate transporting system. The detachment process of the fixed substrate 10 is completed by removing the adhesive 31 adhered between the 11 and the substrate 10.

Thus, the thin film transistor array manufacturing process is completed on the flexible plastic substrate 11.

However, the manufacturing method of the flexible display device according to the related art has the following problems.

The method of manufacturing a flexible display device according to the related art requires a process of adhering a plastic substrate to a glass substrate, and a desorption process of detaching the fixed substrate from the plastic substrate after performing the thin film transistor array manufacturing process, which increases the manufacturing process. As a result, the mass productivity of the product is reduced.

In addition, a pressure-sensitive adhesive is used in the process of adhering a plastic substrate to a fixed substrate made of a glass material. Since the pressure-sensitive adhesive is deteriorated at a temperature higher than about 150 ° C., the high temperature process becomes difficult during the manufacturing process of the thin film transistor array. The reliability of the product is reduced by the process.

In addition, since the plastic substrate and the fixed substrate are adhered with an adhesive, and then the manufacturing process is stably performed, the plastic substrate and the glass substrate must be detached from each other. Therefore, a new adhesive that can maintain a proper adhesive force is required. It is also expensive compared to existing adhesives.

Accordingly, the present invention has been made to solve the above problems of the prior art, the object of the present invention by applying a soluble substrate carrier transport technology by a method for transporting a flexible substrate, such as a plastic substrate is a conventional adhesive The present invention provides a method of manufacturing a flexible display device capable of reducing the manufacturing process such as a process, thereby ensuring mass production of a flexible product.

According to another aspect of the present invention, there is provided a method of manufacturing a flexible display device, including: providing a carrier substrate; Forming a dissolution coating film on the carrier substrate by using a dissolution polymer material; Forming a display device layer on the dissolution coating film; And removing the carrier substrate.

According to the manufacturing method of the flexible display device according to the present invention has the following advantages.

In the manufacturing method of the flexible display device according to the present invention, since the melt coating film is formed on the carrier substrate to be used as the plastic substrate, the adhesion or bonding process between the glass substrate and the plastic substrate using an existing adhesive and the desorption process of the carrier substrate are unnecessary. Therefore, the manufacturing process can be shortened and manufacturing cost can be reduced.

In addition, the present invention can remove the carrier substrate through the etching process after the thin film transistor array manufacturing process is completed can improve the productivity and yield of the product.

In addition, since the present invention does not use a pressure-sensitive adhesive only in a low temperature process as in the prior art, since the manufacturing process is performed in the same process as the existing standard process to manufacture on a glass substrate to improve the reliability of the product even at a high temperature process Can be.

In addition, the carrier metal substrate used in the present invention is cheaper than the existing process because the metal substrate is cheaper than the glass of the same size, the same thickness.

In addition, since the present invention forms a dissolution coating film through a direct coating method, it is possible to form a thickness of about 100 μm or less, and the thickness can be adjusted in a desired form.

Hereinafter, a method of manufacturing a flexible display device according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2A through 2D are cross-sectional views illustrating a method of manufacturing a flexible display device according to an exemplary embodiment of the present invention.

As shown in FIG. 2A, a conventional rigid substrate is first prepared as a carrier substrate 100. In this case, the fixed substrate uses a low cost carrier metal substrate having properties equivalent to that of conventional glass or glass.

Here, the low-cost carrier metal substrate that can be used is cheaper as a metal substrate using a lot of pure iron, and easier to etch later, so a metal containing a lot of pure iron is advantageous. In addition, the carrier metal substrate may be a substrate having a bending characteristic equivalent to that of the existing glass substrate, so as to utilize the existing equipment.

In addition, the carrier metal substrate is inexpensive because the metal substrate is cheaper than glass having the same size and thickness.

Next, as shown in FIG. 2B, a soluble polymer material is directly coated on the carrier substrate 100 to form a soluble coating film 101. In this case, as the dissolved polymer material, a material having high temperature heat resistance characteristics such as polyimide, silica resin, acryl, or the like is used. In addition, the dissolution coating film 101 is used as a plastic substrate having a flexible (flexible) characteristics.

In addition, as a coating method, after dissolving a polymer material on the entire surface of the carrier substrate 100 by spin coating or a coating method such as slit coating, the dissolution coating film 101 may be cured. Form. In this case, since the dissolution coating film 101 should be used as a substrate, a film thickness of at least about 5 μm is formed.

Next, the carrier substrate 100 on which the melt coating film 101 is formed is loaded into a manufacturing process chamber (not shown) through a substrate transport system (not shown), and then a device manufacturing process is performed on the melt coating film 101. Done. In this case, the device manufacturing process refers to manufacturing a display device layer. Here, a thin film transistor manufacturing process will be described, but a process of manufacturing a color filter layer may also be included, or a process of manufacturing these thin film transistors and color filter layers. It may also include.

In this case, referring to FIG. 2C, a device manufacturing process performed on the dissolution coating film 101 is as follows.

As illustrated in FIG. 2C, a metal material is deposited on the dissolution coating layer 101 and then selectively patterned by a mask process to form a gate electrode 103.

In this case, Al-based metals such as Al and Al alloys, Ag-based metals such as Ag and Ag alloys, Mo-based metals such as Mo and Mo alloys, Cr, Ti, Ta and the like.

In addition, they may include two membranes of different material properties, that is, the lower layer and the upper layer thereon. The upper layer is made of a low resistivity metal such as an Al-based metal or an Ag-based metal so as to reduce the signal delay or voltage drop of the gate line.

On the other hand, the lower layer may be made of other materials, especially materials having excellent physical, chemical and electrical contact properties with indium tin oxide (ITO) or indium zinc oxide (IZO), for example, Ti, Ta, Cr, Mo-based metals, or the like. Or an example of the combination of the lower layer and the upper layer is a Cr / Al-Nd alloy.

Next, a gate insulating film 105 made of silicon nitride (SiNx) or the like is formed on the melt coating film 101 including the gate electrode 103.

Subsequently, a high concentration of n + impurities and a semiconductor layer 107 formed of a hydrogenated amorphous silicon layer and the like are doped on the gate insulating layer 105 by using a plasma enhanced chemical vapor deposition (PECVD) method. The n + silicon layer 109 is formed continuously. In this case, the n + silicon layer 109 is used as an ohmic contact layer of the thin film transistor.

Subsequently, the n + silicon layer 109 and the semiconductor layer 107 are selectively patterned by a mask process.

Subsequently, a metal material is deposited on the gate insulating layer 105 including the selectively patterned n + silicon layer 109 and then selectively patterned by a mask process to form a source electrode 111 and the source electrode ( 111 and drain electrodes 113 spaced apart from each other by channel length are formed. In this case, an area between the source electrode 111 and the drain electrode 113, that is, a portion of the n + silicon layer 109 positioned in the channel area is exposed to the outside. In this way, the source electrode 111 and the drain electrode 113 together with the semiconductor layer 107 and the gate electrode 103 thereunder constitute a thin film transistor as a switching element.

In addition, a channel of the thin film transistor is formed in the semiconductor layer 107 between the source electrode 111 and the drain electrode 113.

As the metal material for forming the source electrode 111 and the drain electrode 113, a material such as an Al-based metal, an Ag-based metal, a Mo-based metal, Cr, Ti, Ta, or the like is used. You may.

Subsequently, an organic material having excellent planarization characteristics and photosensitivity, an insulating material having low dielectric constant characteristics, or silicon nitride, which is an inorganic material, may be formed on the melt coating film 101 including the source electrode 111 and the drain electrode 113. A protective film 115 is formed.

Subsequently, the protective film 115 is selectively patterned by a mask process to form a contact hole (not shown) for exposing a part of the drain electrode 113 in the protective film 115.

Next, a metal layer (not shown) made of a transparent conductive material such as ITO or IZO is deposited on the passivation layer 115 including the contact hole (not shown), and then selectively removed by the mask process to form a pixel electrode ( 119).

In this manner, the process of manufacturing the thin film transistor array for display device on the melt coating film 101 is completed.

Subsequently, as shown in FIG. 2D, the carrier substrate 100 is completely removed by the front etching process, thereby separating the carrier substrate 100 and the dissolution coating film, that is, the plastic substrate 101. In this case, when the carrier substrate 100 is a metal, it is possible to etch by spray or dipping method using iron chloride (FeCl ₂ ), in the case of the carrier substrate 100 is glass (fluoric acid) Etching is also possible by dipping method or spray method.

Although only the process of forming a thin film transistor on the flexible substrate of this invention was described, it turns out that it is applicable also in the process of forming a color filter layer.

Meanwhile, a method of manufacturing a flexible display device according to another exemplary embodiment of the present invention will be described with reference to FIGS. 3A to 3D.

3A to 3D are cross-sectional views illustrating a method of manufacturing a flexible display device according to another exemplary embodiment of the present invention.

As shown in FIG. 3A, a conventional rigid substrate is prepared as a carrier substrate 200. In this case, the fixed substrate uses a low cost carrier metal substrate having properties equivalent to that of conventional glass or glass.

Here, the low-cost carrier metal substrate that can be used is cheaper as a metal substrate using a lot of pure iron, and easier to etch later, so a metal containing a lot of pure iron is advantageous. In addition, the carrier metal substrate may be a substrate having a bending characteristic equivalent to that of the existing glass substrate, so as to utilize the existing equipment.

In addition, the carrier metal substrate is inexpensive because the metal substrate is cheaper than glass having the same size and thickness.

Next, as shown in FIG. 3B, a soluble polymer material is directly coated on the carrier substrate 200 to form a soluble coating film 201. In this case, as the dissolved polymer material, a material having high temperature heat resistance characteristics such as polyimide, silica resin, acryl, or the like is used. In addition, the dissolution coating film 201 is used as a plastic substrate having a flexible (flexible) characteristics.

In addition, as a coating method, the carrier substrate 200 may be formed by a spin coating method or a coating method such as a slit coating method or a method in which these spin coatings and a slit coating are mixed. ) After dissolving the polymer material on the front surface is cured to form a dissolution coating film 201. In this case, since the dissolution coating film 201 should be used for a substrate, a film thickness of at least about 5 μm is formed.

Next, the carrier substrate 200 on which the melt coating film 201 is formed is loaded into a manufacturing process chamber (not shown) through a substrate transport system (not shown), and then a device manufacturing process is performed on the melt coating film 201. Done. In this case, the device manufacturing process refers to manufacturing a display device layer. Here, a thin film transistor manufacturing process will be described, but a process of manufacturing a color filter layer may also be included, or a process of manufacturing these thin film transistors and color filter layers. It may also include.

In this case, a device manufacturing process performed on the dissolution coating film 201 will be described with reference to FIG. 3C.

As shown in FIG. 3C, a metal material is deposited on the dissolution coating layer 201 and then selectively patterned by a mask process to form a gate electrode 203.

In this case, Al-based metals such as Al and Al alloys, Ag-based metals such as Ag and Ag alloys, Mo-based metals such as Mo and Mo alloys, Cr, Ti, Ta and the like.

In addition, they may include two membranes of different material properties, that is, the lower layer and the upper layer thereon. The upper layer is made of a low resistivity metal such as an Al-based metal or an Ag-based metal so as to reduce the signal delay or voltage drop of the gate line.

On the other hand, the lower layer may be made of other materials, especially materials having excellent physical, chemical and electrical contact properties with indium tin oxide (ITO) or indium zinc oxide (IZO), for example, Ti, Ta, Cr, Mo-based metals, or the like. Or an example of the combination of the lower layer and the upper layer is a Cr / Al-Nd alloy.

Next, a gate insulating film 205 made of silicon nitride (SiNx) or the like is formed on the melt coating film 201 including the gate electrode 203.

Subsequently, a high concentration of the n + impurity and a semiconductor layer 207 made of a hydrogenated amorphous silicon layer and the like are doped on the gate insulating layer 205 using plasma enhanced chemical vapor deposition (PECVD). The n + silicon layer 209 is formed continuously. In this case, the n + silicon layer 209 is used as an ohmic contact layer of the thin film transistor.

Subsequently, the n + silicon layer 209 and the semiconductor layer 207 are selectively patterned by a mask process.

Next, a metal material is deposited on the gate insulating film 205 including the selectively patterned n + silicon layer 209 and then selectively patterned by a mask process to form a source electrode 211 and the source electrode ( 211 and the drain electrode 213 spaced apart from each other by the channel length are formed. In this case, an area between the source electrode 211 and the drain electrode 213, that is, a portion of the n + silicon layer 209 positioned in the channel area is exposed to the outside. In this way, the source electrode 211 and the drain electrode 213 together with the semiconductor layer 207 and the gate electrode 203 thereon constitute a thin film transistor as a switching element.

In addition, a channel of the thin film transistor is formed in the semiconductor layer 207 between the source electrode 211 and the drain electrode 213.

As the metal material for forming the source electrode 211 and the drain electrode 213, an Al-based metal, an Ag-based metal, a Mo-based metal, Cr, Ti, Ta, or the like is used, and formed in multiple layers. You may.

Subsequently, an organic material having excellent planarization characteristics and photosensitivity, an insulating material having low dielectric constant characteristics, or silicon nitride, which is an inorganic material, may be formed on the melt coating film 201 including the source electrode 211 and the drain electrode 213. A protective film 215 is formed.

Subsequently, the passivation layer 215 is selectively patterned by a mask process to form a contact hole (not shown) exposing a part of the drain electrode 213 in the passivation layer 215.

Next, a metal layer (not shown) made of a transparent conductive material such as ITO or IZO is deposited on the passivation layer 215 including the contact hole (not shown) and then selectively removed by a mask process to remove the pixel electrode ( 219).

In this way, the process of manufacturing the thin film transistor array for display device on the melt coating film 201 is completed.

Thereafter, as shown in FIG. 3D, the carrier substrate 200 needs to be removed. When the dissolution coating layer is applied to an active matrix organic light emitted diode device (AMOLED), a dissolving plastic such as moisture absorption is applied. In order to prevent such a problem, the film may be prevented from being etched such that only the carrier substrate 200a remains as shown in FIG. This remaining part is used for barrier use. At this time, the remaining carrier substrate 200a serves as a protective sheet as well as the barrier to prevent moisture absorption and external scratches of the plastic substrate. In addition, it is possible to omit a separate barrier (barrier) forming process that was previously performed can simplify the manufacturing process.

In addition, when removing a portion of the carrier substrate 200 by an etching process, when the carrier substrate 200 is a metal, it can be etched by a spray method using iron chloride (FeCl ₂ ) or a dipping method. In the case where the carrier substrate 200 is made of glass, etching may be performed using a dipping method or a spray method using hydrofluoric acid.

Although only the process of forming a thin film transistor on the flexible substrate of this invention was described, it turns out that it is applicable also in the process of forming a color filter layer.

Meanwhile, the manufacturing method of the flexible display device according to the present invention is applicable to an electrophoretic display device, an organic light emitting diode (OLED), a liquid crystal display device, or other display devices.

Although the above has been described with reference to the preferred embodiment of the present invention, those skilled in the art various modifications and changes to the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1A to 1D are cross-sectional views illustrating a method of manufacturing a flexible display device according to the related art.

2A through 2D are cross-sectional views illustrating a method of manufacturing a flexible display device according to an exemplary embodiment of the present invention.

3A to 3D are cross-sectional views illustrating a method of manufacturing a flexible display device according to another exemplary embodiment of the present invention.

*** Description of the main parts of the drawing ***

100: carrier substrate 101: melt coating film

103: gate electrode 105: gate insulating film

107: semiconductor layer 109: n + silicon layer

111 source electrode 113 drain electrode

115: protective film 119: pixel electrode

Claims (10)

Providing a carrier substrate; Forming a dissolution coating film on the carrier substrate by using a dissolution polymer material; Forming a display device layer on the dissolution coating film; And Removing the carrier substrate; and a method of manufacturing a flexible display device. The flexible coating of claim 1, wherein the dissolution coating layer is formed by spin coating, slit coating, or a mixture of spin coating and slit coating. Display device manufacturing method. The method of claim 1, wherein a material having high temperature heat resistance such as polyimide, silica resin, or acrylic is used as the dissolved polymer material. The method of claim 1, further comprising curing the melt-coated film and then curing the film. The method of claim 1, wherein the carrier substrate is a glass or metal substrate. The method of claim 5, wherein the display device layer comprises a thin film transistor, a color filter layer, or a thin film transistor and a color filter layer. The method of claim 5, wherein when the metal substrate or the glass substrate is used as the carrier substrate, the carrier substrate is etched by spraying or dipping using iron chloride (FeCl ₂ ). . The method of claim 1, wherein all of the carrier substrates are removed or only some of the carrier substrates remain. The method of claim 8, wherein when the carrier substrate is partially removed, the remaining carrier substrate is used as a barrier. The method of claim 9, wherein the method of manufacturing the flexible display device is applied to a display device including an electrophoretic device, a liquid crystal display, and an organic light emitting display device.

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