KR100978252B1 - Fabrication method of liquid crystal display device - Google Patents

Abstract

The present invention relates to a method of manufacturing a reflective liquid crystal display device, comprising the steps of: preparing a substrate in which a pixel region is defined; Printing a resist pattern on the pixel area; Heat-treating the resist pattern to form a wave-shaped uneven layer having a round surface; Comprising a step of forming a reflective film on the uneven layer, by using a printing method when forming the uneven layer, it is possible to simplify the pattern forming process.

Description

Manufacturing method of liquid crystal display device {FABRICATION METHOD OF LIQUID CRYSTAL DISPLAY DEVICE}

1 is a view of a typical reflective liquid crystal display device.

2A to 2D are process flowcharts showing the unevenness forming process of a conventional reflective liquid crystal display device;

3A to 3D are process flowcharts showing the unevenness forming process of a conventional reflective liquid crystal display device;

4A to 4C are process flowcharts illustrating a method of manufacturing a liquid crystal display device according to the present invention.

5 is a process flowchart showing a process of forming irregularities of the liquid crystal display according to the present invention.

6 is a process flowchart showing a process of forming irregularities of the liquid crystal display device according to the present invention.

*** Explanation of symbols for main parts of drawing ***

200, 305: printing roll 201, 202: resist

205: convex portion 210, 310: doctor blade

300: cliché

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a process of forming an uneven layer of a reflective liquid crystal display device that can simplify the process.

The liquid crystal display device is used in various fields such as an electronic notebook, a portable information terminal, a game machine, a mobile phone, etc. in addition to a notebook type word processor, a notebook personal computer, and the like. In particular, in the case of portable communication devices, a low power consumption type display is required to carry a portable device for a long time.

In the case of a transmissive liquid crystal display device having a separate light source including a back light, the backlight occupies 80% or more of the power consumption, so that a reflective liquid crystal without a backlight is used to make a low power consumption liquid crystal display device. Display elements are required. In the case of the reflective liquid crystal display device, since the image must be expressed using only external light, maximizing the light efficiency is the maximum research point of the reflective liquid crystal display device. Therefore, many studies have been conducted to improve the light efficiency.

As shown in FIG. 1, a general reflective liquid crystal display device includes a thin film transistor substrate 10, a color filter substrate 20, and a liquid crystal layer 30 formed therebetween.

The color filter substrate 20 has a black matrix 2 for preventing light leakage between pixels, and a common voltage for applying a voltage to the color filter 4 and the liquid crystal layer 30 to substantially realize color. The electrode 6 is formed.

The thin film transistor substrate 10 includes a thin film transistor T disposed at each pixel to serve as a switching for applying and blocking a signal voltage to the liquid crystal, a protective film 9 and a thin film transistor for protecting the thin film transistor. A pixel electrode 11 is formed to apply a signal voltage applied through the T to the liquid crystal cell. The thin film transistor T includes a gate electrode 1 to which a scan signal is applied and data corresponding to the scan signal. An active layer 5 provided to transmit a signal, a gate insulating film 3 that electrically isolates the active layer 5 and the gate electrode 1, and an upper portion of the active layer 5 to apply a data signal. A source electrode 7a, a drain electrode 7b for applying a data signal to the pixel electrode, and a protective film 9 for protecting it. At this time, a contact hole 9a for exposing a part of the drain electrode 7b is formed in the passivation layer 9, and the drain electrode 7b and the pixel electrode 11 are electrically connected to each other.

The pixel electrode (hereinafter referred to as a reflecting plate) 11 is formed of an opaque metal material having excellent reflectance to serve as a reflecting film. In this case, the reflective plate 11 mainly uses a metal film made of aluminum or an aluminum alloy (AlNd; Aluminum-Neodymium) having excellent interface reflection characteristics. In addition, in order to improve the reflection efficiency of the external light, the uneven structure is formed in the reflecting plate 11, which is due to the structure of the protective film 9 formed in the lower portion. That is, by forming the surface of the protective film 9 to have irregularities, the reflective plate 11 formed thereon may also be formed on the surface along the shape of the protective film 9.

As described above, the unevenness may be formed by patterning the protective film itself, or after coating a separate film on the protective film, and then patterning it by a photo mask process.

Through the drawings will be described in more detail with respect to the conventional method of forming irregularities.

2A to 2D are process flowcharts illustrating a conventional process of forming irregularities. First, as shown in FIG. 2A, spin coating or roll coating is performed on the substrate 21 on which the protective film 23 is formed. the photoresist film 25 of the polymer resin is uniformly applied by applying a roll coating method, and then the photoresist film 25 is applied to the mask 27 on which the non-transmissive areas A to D are selectively formed. After blocking, the UV (arrow on the drawing) is irradiated.

Next, as shown in FIG. 2B, the photoresist film 25 irradiated with the ultraviolet rays is developed to form a pattern 25a of photoresist selectively remaining on the protective film 23. Thereafter, a portion of the protective film 23 is removed using the photoresist pattern as a mask to form the convex pattern 23a. Then, as shown in FIG. 2C, after removing the photoresist pattern 25a remaining on the protective film 23, the surface of the protective film is interposed between the convex pattern 23a and the pattern through a curing process. By making part melt, the surface forms the unevenness | corrugation 23b which has a natural embossing wave.

Lastly, as shown in FIG. 2D, an opaque metal material such as aluminum or aluminum (AlNd) is deposited on the protective film 23 having the unevenness 23b on the surface thereof, and thus may serve as a reflective film. (29) is formed.

3A to 3E illustrate a conventional method for forming another unevenness, and after forming a resist pattern on the passivation layer, the unevenness is formed.

 First, as shown in FIG. 3A, a spin coating or roll coating method is applied on the substrate 31 on which the protective film 33 is formed to form the first photoresist film 35a of the polymer resin. Is uniformly applied, and then the photoresist film 35a is blocked through a mask 37 prepared in advance, and then UV (arrow on the drawing) is irradiated. Next, as shown in FIG. 3B, the photoresist film irradiated with the ultraviolet rays is developed to form a pattern 35b of photoresist selectively remaining on the protective film 33. Next, as shown in FIG. 3C, the surface of the photoresist pattern 35c is rounded through a curing process, and thereafter, the second photoresist film 35d is formed thereon. ) So that the valleys between the photoresist patterns 35c are filled. Finally, as shown in FIG. 3E, an opaque metal material such as aluminum or aluminum (AlNd) is deposited on the second photoresist film 35d to form a reflector plate 39 which may serve as a pixel electrode. do.

As described above, one photomask process is conventionally added to form irregularities in the pixel electrode, and the photomask process is performed by a process such as photoresist coating-> exposure-> developing-> etching-> strip. Because it is made through the process is not only complicated, there is a problem that the productivity is reduced due to the increase in manufacturing cost and the number of processes.

In addition, after the application of the photoresist and before the exposure proceeds, the alignment between the mask and the substrate should be made. At this time, the alignment error occurs due to the characteristics of the alignment equipment, it was difficult to form irregularities in the correct position.

Accordingly, the present invention has been made to solve the above problems, the object of the present invention is to form a reflective plate having a concave-convex surface through a printing method without a separate photo mask process, the process is simple and can reduce the manufacturing cost It is to provide a method of manufacturing a liquid crystal display device.

Other objects and features of the present invention will be described in detail in the configuration and claims of the following invention.

The present invention for achieving the above object comprises the steps of preparing a substrate in which the pixel region is defined; Printing a resist pattern on the pixel area; Heat-treating the resist pattern to form a concave-convex layer having a rounded wave shape; And forming a reflective film on the resist pattern t film. In this case, the printing of the resist pattern may include preparing a printing roll having a plurality of grooves formed at a position corresponding to a region where a pattern is to be formed; Filling a resist into the groove; The printing roll filled with the resist is connected to the substrate, and then printed on the pixel area, which is very simple compared to the conventional photo mask process.

Hereinafter, a method of manufacturing a liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.                     

4A to 4C are process flowcharts for describing a method of manufacturing a liquid crystal display according to the present invention. First, as shown in FIG. 4A, a substrate in which a thin film transistor T and a pixel region P are defined ( Prepare 100).

The thin film transistor T includes a gate electrode 101, a semiconductor layer 103 formed thereon, and a source / drain electrode 105a / 105b. The thin film transistor T is formed through the following process. The drawings will be omitted here.

First, a first metal layer such as aluminum (Al), copper (Cu), or the like is deposited on the transparent substrate 100, and then patterned to form a gate electrode 101, and then an inorganic material, such as SiNx or SiO 2, on the entire upper surface thereof. The material is deposited to form the gate insulating layer 102. Subsequently, n + amorphous silicon doped with impurities such as amorphous-Si and phosphorous (P) is sequentially deposited on the gate insulating layer 102 on the gate insulating layer 102, and then patterned to form an active layer. The semiconductor layer 103 composed of the 103a and the ohmic contact layer 103b is formed. Then, a second metal layer such as molybdenum (Mo), molybdenum alloys (MoTa, MoW), etc. is deposited on the semiconductor layer 103, and then patterned to form a source / space spaced apart on the semiconductor layer 103. The thin film transistor T is fabricated by forming the drain electrodes 105a / 105b.

After forming the thin film transistor T through the above process, as shown in FIG. 4B, an inorganic material such as SiOx, SiNx, BCB or the like is formed on the entire surface of the substrate including the thin film transistor T and the pixel region P. After the photoacryl and the organic material are applied, a protective film 107 is formed to expose a portion of the drain electrode 105b by patterning.                     

Next, as shown in FIG. 4C, the patterned resist pattern is printed on the passivation layer 107 of the pixel region P to form the uneven layer 109, and then aluminum or aluminum is formed thereon. After depositing a metal material having excellent reflection characteristics such as an alloy (AlNd; Aluminum-Neodymium), the reflective plate 110 is formed to be connected to the drain electrode 105b.

Hereinafter, the forming process of the uneven layer will be described in detail with reference to the accompanying drawings.

FIG. 5 illustrates a process of forming unevenness through processing of a printing roll. First, as shown in FIG. 5A, a recess 201 is formed on a surface of the printing roll 200 through processing of the printing roll 200. The resist 202 is filled in the groove 201. In addition, the resist 202 is also applied to the surface of the printing roll 200. At this time, the surface of the printing roll 200 is pushed flat using a doctor blade 210 so that the resist may be uniformly applied. Thereafter, as shown in FIG. 5B, the printing roll 200 in which the resist 202 is uniformly applied is aligned at the position of the substrate 250 on which the pattern is to be formed, and then the printing roll on the substrate 250 is aligned. By contacting and rotating the 200, as shown in Fig. 5C, a resist pattern 204 having a uniform thickness and having a plurality of convex portions 205 on its surface is formed. In this case, a protective film is formed on the substrate 250, and the resist pattern 204 is printed on the protective film, and the convex portion 205 of the resist pattern 204 is formed along the shape of the groove formed in the printing roll. . Subsequently, as shown in FIG. 5D, through the heat treatment of the resist pattern 204, an uneven layer 207 having a natural wave formed between the convex portions is formed, and then the reflective film 209 is formed thereon. To form. At this time, the heat treatment of the resist for forming the uneven layer is made at a temperature of about 300 degrees, and the heat treatment temperature is not limited in the present invention because it must be changed according to the viscosity of the resist to be used.

Fig. 6 shows a printing method using a cliché. Instead of forming a concave groove in the printing roll, a separate concave plate (cliché) is provided to form a pattern. First, as shown in FIG. 6A, after preparing a cliché 300 having a concave groove formed at a position corresponding to a region where a pattern is to be formed, and then applying a resist 302 thereon, the doctor blade 310 The resist 302 is filled only in the groove 301 by using the N-, and all the resist remaining on the surface of the cliché 300 is removed. Subsequently, as shown in FIG. 6B, a printing roll 305 having a flat surface is prepared, and then connected to the cliché 300, and then the printing roll 305 is rotated to thereby form a groove in the cliché 300. The filled resist 302 is transferred to the surface of the printing roll 305. Thereafter, as shown in FIG. 6C, the resist 302 deposited on the printing roll 305 is retransmitted on the substrate 350 to form a resist pattern 307. Next, the resist pattern 307 is heat-treated to form a plurality of irregularities 308 by rounding the surface thereof, as shown in FIG. 6D, and then, by depositing an opaque metal material on the irregularities 308, a reflective film 309 is formed. At this time, the surface of the reflective film 309 forms an uneven portion caused by the resist pattern, which serves to more effectively reflect the external light to further improve the brightness of the screen.                     

In addition, although not shown in the drawings, the substrate and the cliché are directly contacted with each other without using a printing roll as a means for transferring the resist filled in the cliché onto a substrate, and then, after applying heat or pressure thereto, the substrate A resist pattern can also be formed in a board | substrate by peeling from a Cliché.

The profile of the unevenness is a main factor in determining the reflectance of external light in the reflective liquid crystal display. Therefore, controlling the shape of the uneven pattern well determines the luminance of the reflective liquid crystal display element. However, the conventional method of forming the unevenness through the photomask process has been very difficult to select the photoresist PR because the shape of the unevenness depends on the heat treatment characteristics of the selected photoresist PR. On the other hand, when the printing method is used, the shape of the unevenness can be adjusted by selecting the viscosity of the resist regardless of the heat treatment characteristics of the resist, so the dependency of the material is low. On the other hand, the biggest factor that determines the shape of the unevenness in the printing method is the shape of the groove formed in the printing roll or the cliché, which can be realized by processing of the printing roll and the cliché.

As described above, according to the present invention, as the irregularities are formed in the pixel region through the printing method, the reflectance can be improved, and the productivity can be improved by simplifying the process.

Claims (6)

Preparing a substrate in which a thin film transistor and a pixel region are defined; Forming a protective film on the entire surface of the substrate; Processing the concave groove at a position corresponding to the pattern to be formed on the printing roll surface; Filling the resist into the groove of the printing roll and applying the resist to the surface of the printing roll; Transferring the resist onto the protective film; Heat treating the resist pattern to form a wave-shaped uneven layer; Forming a reflective film on the concave-convex layer. delete delete The method of claim 1, wherein forming the thin film transistor comprises: forming a gate electrode; Forming a gate insulating film on the gate electrode; Forming a semiconductor layer on the gate insulating film; And forming source and drain electrodes spaced apart from each other by a predetermined interval on the semiconductor layer. The method of claim 4, wherein a portion of the drain electrode is connected to the reflective film. delete

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