KR100242435B1 - Color filter of liquid crystal display and method of production thereof - Google Patents

Abstract

The present invention relates to a color filter for LCD and a method of manufacturing the same. A positive color film such as a film film or a slide film for producing precise forms and accurate chromaticities of three primary colors of light, such as R, G, and B colors. It is using the phenomenon.

In other words, using a single photomask patterned with chromium on a substrate coated with a positive photoresist having heat resistance and chemical resistance, each part is exposed to a stepper while being exposed to each of three R, G, and B primary colors having the same height. At the same time, the black black matrix, which is a portion in which the three primary colors of R, G, and B overlap with each other by the mask pattern during exposure, is exposed to the same height as the three primary colors of the R, G, and B primary colors. Because it is formed, it is possible to finish three or more coating and etching processes at the same time in manufacturing color filter, which simplifies the process, the same color control and high reliability LCD that can reduce the effort for smoothing the surface of color filter. A color filter can be realized.

Description

Color filter for liquid crystal display device and manufacturing method thereof

1 (a) to 1 (d) is a manufacturing process diagram of the color filter for LCD according to the prior art.

2 is a cross-sectional view of a photomask according to the present invention.

3 (a) to 3 (e) are manufacturing process diagrams of the color filter for LCD according to the present invention.

[Industrial use]

The present invention relates to a color filter for a liquid crystal display (LCD), and more particularly, to simplify the manufacturing process using the principle of the color film (COLOR FILM) for the LCD that can improve the spectral characteristics, durability and surface smoothness A color filter and a method of manufacturing the same.

[Prior Art and Problem]

Recently, with the spread of OA devices and portable small TVs, LCD displays, electroluminescence sensor (EL) devices, plasma displays (PDP), and light emitting diodes (LEO) are used instead of CRTs. ), Researches on fluorescent display tubes (VFD), etc. have been actively promoted, and some have been put into practical use.

Among them, the liquid crystal display is extremely lightweight, thin, low-cost, low power consumption, and has a good match with integrated circuits.It is also equipped with a color for vehicle loading, in addition to the display of a LAP TOP COMPUTER or a Pocket COMPUTER. Its use is rapidly expanding for TV images.

In addition, the color filter used in the LCD is 3-5 inches in practical use, 10-14 inches are under development, and is rapidly progressing toward larger size.

Like CRT, COLOR FILTER is a technology that realizes color by using three primary colors of light (R. G. B) as a basic unit of pixels and controlling the intensity of the same three colors, that is, the intensity of light passing through.

The color characteristics are most advantageous in the active matrix liquid crystal panel with a contrast ratio of about 40: 1. Triple pixels), resulting in increased peripheral ICs (DRIVER, etc.), higher costs, lower YIELD, etc.

Conventional methods for forming a color filter include a printing method, a deposition method, an electrodeposition method, a pigment dispersion method, and the like, and a dyeing method is generally used. The dyeing method is divided into positive and negative methods according to the usage of the resist, and natural THROUGH-BACK materials such as gelatin and casein are used as the dyeing layer, but gelatin is easy to dye.

This LCD technology requires the most uniformity of GELL GAP uniformity. For this purpose, the surface of the color filter must be flat and excellent process technology is required.

The dyeing process of the color filter includes a mask (MASK) method and a pattern (PATTERN) method, the pattern method is excellent in smoothness, there is an advantage in the practical use, but when using a positive resist, technical problems such as unstable isolation is followed.

Here, in particular, the dyeing method and the pigment dispersion method having a similarity to the present invention. The dyeing method is mainly applied in color filters for LCDs to form a chromium black matrix on a glass substrate, uniformly apply gelatin, casein, and the like, and then form R.G.B by photolithography and dyeing techniques.

The same technology is used in general photographic technology, so it can get good smoothness and etching is relatively easy, so it is possible to PATTERN compared to other technologies and shows excellent characteristics in color and fine processing. It has disadvantages such as complexity, difficulty in managing the dyeing solution and poor heat resistance of the dyeing medium.

On the other hand, the pigment dispersion method is a process of applying a black matrix (BLACK MATRIX), R, G, B for photosensitivity to SPINNER and patterning with photo lithography (PHOTO LITHOGRAPHY), the smoothness of film formation and filter While the distinction of filter edge is clear, the disadvantage of this technology is based on the photolithography method, which makes the process complicated and the black matrix and the R, G, B pattern are bent, which makes the unevenness of the part harder. There is a number.

As described above, the dyeing method and the pigment dispersion method have a similarity to the present invention in that the photolithography technique is used, but it can be seen that the principle of color development is fundamentally different.

That is, the dyeing method and the pigment dispersion method is to form a black matrix of chromium, and then form the colors of R, G, and B separately, and in the case of the dyeing method, each of the dyes R, G, and B is exposed and patterned by dye. G, B dyeing and color development. Pigment dispersion method is a pattern of R, G and B exposure by dispersing and coloring pigments coloring the photosensitive resin itself, and top coat (TOP) for surface smoothness and durability. COAT) layer is formed and ITO is sputtered.

Meanwhile, the role of the photolithography process, that is, the photoresist film and the etching process in the semiconductor field, is to reduce and integrate various unit active and passive semiconductor devices to have electrical functions, thereby reproducing the structural shaping of the circuit on the semiconductor substrate. Its main purpose has already been recognized.

The liquid crystal display panel manufactured using the above technique is a bottom substrate on which a thin film transistor (THIN FILM TRANSISTOR) TFT is formed, that is, a TFT substrate, a liquid crystal layer, and three color filter layers of R, G, and B are repeatedly arranged. It is composed of an upper substrate for colorization, an overcoat layer formed on the upper substrate, and an indium tin oxide (ITO) transparent electrode film.

A conventional color filter manufacturing method related to the manufacture of the upper substrate on which the color filter layer is formed will be described with reference to FIGS. 1 (a) to 1 (d).

1 (a) to 1 (d) show a manufacturing process diagram of the LCD color filter according to the prior art, and the glass substrate for LCD 12 subjected to CP (CUTTING, POLISHING) treatment as shown in the drawing. ) Is formed by sputtering and patterning chromium to a thickness of about 1000-2000 Å on the light blocking black matrix 11 to prevent deterioration and mixing of the TFT.

Then, a negative photoresist (NEGATIVE PHOTORESIST) having optimized spectral characteristics, for example, a colored acrylic photosensitive resin in which a pigment is dispersed, is coated on a transparent substrate 12 having a black matrix made of chromium (Cr) material to a thickness of 1.5-2.0 μm. Soft bake for 90 seconds on a hot plate at 80-110 ° C., and then a transparent resin such as an oxygen barrier film (PVA) is applied on the already formed colored film to prevent oxidation of the resist generated during exposure. After drying, exposure is performed using the photomask 10 with ultraviolet rays. After exposure, the oxygen barrier film is stripped with DIW for 5 minutes. The photomask 10 is a pattern of the chromium pattern 15 on a quartz (QUARTZ) 14 which is a kind of transparent substrate.

Then, the solution is developed for 2-3 minutes and then rinsed with DIW (DEIONIZED WATER) for 90 seconds to form a first color filter layer 21 having optimized red spectroscopic characteristics.

Colored acrylic having an optimized green spectral characteristic on the glass substrate 12 to be partially overlapped on the black matrix 11 and separated from the first color filter layer 21 in the same manner as the first color filter layer 21. The second color filter layer 22 of the photosensitive resin is formed.

Subsequently, the third color filter layer 23 of the colored acrylic resin superimposed on the black matrix 11 and having the optimized blue spectral characteristics on the glass substrate 11 is separated from the second color filter layer 22. Form.

In order to protect them from external impacts on the black matrix 11 and the color filter layers 21, 22, and 23 and improve smoothness, for example, polyimide, polyacrylate, polyurethane and the like have high surface hardness and excellent light transmittance. After forming the transparent resin to a thickness of about 0.5-3㎛ and heated for 5 minutes at 150-220 ℃ hot plate to form a protective film (OVER COAT LAYER) (24).

Thereafter, the upper substrate is formed by forming a transparent electrode film 25 of ITO having a thickness of about 500-1300 kPa on which the voltage for driving the liquid crystal is applied on the entire surface of the protective film 24.

In the conventional color filter formed in this manner, a difference occurs in the amount of light absorption after development (DEVELOP) due to the absorption and reflection of light by the colored photoresist film during exposure, thereby changing the shape of the pattern edge part (EDGE part). The upper layer part easily reaches the light has a large pattern, and the lower layer part where the absorption of light is disturbed by the color is not absorbed by the light, so that the cross-linking is not sufficient, so that the color filter pattern has an inverted triangle shape.

If the ITO electrode is deposited in such a state, disconnection occurs at the pattern edge part. Therefore, the unevenness of the pattern edge part is flattened by applying and drying acrylic or polyimide resin having excellent flatness on the pattern to prevent short circuit of the ITO electrode. An ITO electrode was deposited to complete the color pattern.

As described above, if the R, G, B colored film is planarized using a protective layer material and then ITO sputtering, problems such as disconnection of ITO do not occur, but defects and throughput due to the protective film process are reduced. And because of the high cost of materials, there was a problem in terms of cost reduction.

In addition, when the characteristics of the color filter are viewed in terms of spectral characteristics, durability, surface smoothness, etc., the color filter formed by the conventional method should have red light, green and blue colors of about 30% and three primary colors of light. In order to prevent the process, such as forming a black matrix separately from chromium, and the resulting smoothness of the surface is caused by problems.

[Purpose of invention]

Accordingly, the present invention has been made in view of the above, and by forming three primary colors and a black matrix of light on one plane with three exposures, the process is simplified and the thickness of the filter pattern is reduced to improve the transmittance of the color filter. An object of the present invention is to provide a color filter for LCD and a method of manufacturing the same, which can improve surface smoothness.

[Configuration of Invention]

Color filter for LCD of the present invention for achieving the above object is a plurality of black matrix formed at a predetermined interval to prevent degradation and mixing of the thin film transistor on the substrate coated with a positive color photosensitive liquid, and between the black matrix And a first to third color filter layers sequentially separated from each other at the same height as the black matrix, and a transparent electrode film coated on the black matrix and the color filter layer formed at the same height.

Meanwhile, in the method of manufacturing the color filter, first to third color filter layers having the same height are sequentially formed on the substrate on which the positive color photosensitive liquid is applied, and at the same time, the first to third color filter layers are formed. Forming a black matrix at predetermined intervals to prevent deterioration and mixing of the thin film transistor at the same height as the filter layer in between; And forming a transparent electrode film on the planarized black matrix and the first to third color filter layers.

[Action]

According to the above-described configuration, since the three primary colors and the black matrix of light are formed at the same height on three planes in three exposures, there is no terminal between the R, G, and B patterns and the black matrix, so that the flattening is performed. Even if ITO film is directly applied on G, B film and black matrix, defects such as ITO disconnection do not occur, which can reduce the effort for smoothing the surface of color filter, and at least three coating and etching processes in manufacturing color filter Can be done all at once, simplifying the process.

EXAMPLE

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 shows a cross-sectional view of a photomask used in the present invention, and FIGS. 3 (a) to 3 (e) show a manufacturing process of the color filter for LCD according to the present invention.

In general, the color filter of the upper substrate is required for colorization of a flat panel display device such as an LCD, and when the characteristics of the color filter are classified into spectral characteristics, durability, and surface smoothness, the three primary colors of light are red, green, and In order to produce a precise form and accurate chromaticity of a blue pixel, the present invention uses a principle of a positive color film phenomenon such as a movie film or a slide film phenomenon.

Referring to FIGS. 3 (a) to 3 (e), the color filter according to the present invention is prescribed to prevent deterioration and mixing of the thin film transistors on the substrate 12 to which the positive color photosensitive liquid 61 is applied. A plurality of black matrices 72 formed at intervals and the first to third color filter layers 60 sequentially formed by being separated from the black matrix 72 at the same height as the black matrix 72 and sequentially formed. It can be seen that the structure of the transparent electrode film 71 coated on the black matrix 72 and the color filter layer 60 formed at a height.

The manufacturing method of the color filter having the above structure can be largely divided into two steps. One of the first to third colors having the same height using a photo mask on the substrate 12 to which the positive color photosensitive liquid 61 is applied is applied. In order to form the color filter layer 60 in sequence and at the same height as the filter layer 60 between the first to third color (60) filter layer to prevent deterioration and mixing of the thin film transistor at a predetermined interval (black matrix ( 72, and the other is forming the transparent electrode layer 71 on the planarized black matrix 72 and the first to third color filter layers 60.

In the photomask, the chromium pattern 52 is patterned on the quartz substrate 51. The mask pattern used in the present invention is two chromium patterns 52 successively spaced apart by a predetermined interval, and the width of the chromium pattern is changed again. The chrome pattern 52 has a size of 100 (W) * 320 (H) μm.

The manufacturing method of the LCD color filter structure according to the present invention will be described below based on the above-described configuration and manufacturing process.

As shown in FIG. 3 (a), a positively durable positive color photosensitive liquid 61 is first applied to a transparent substrate 12 such as glass, quartz, or a polymer film to obtain a film having good adhesion.

Thereafter, a photomask designed according to a pixel pattern (stripe, mosaic, delta type) suitable for the characteristics of the display element is placed and exposed in red. At this time, the exposure is exposed while moving the various parts to the stepper according to the screen size, as a result, the positive color photosensitive film 61 of the portion where the chromium pattern 52 is not formed is reduced to red and thus the third (b) A first color filter layer 63 is formed as shown in FIG.

Subsequently, on the substrate on which the first color filter layer 63 is formed in the same manner, the photoresist film is further exposed to green and blue colors by exposing the photoresist film two times while moving several portions with a stepper according to the screen size. ) And second color 64 and third color 65 filter layers as shown in FIG. 3 and (d).

In this case, the black matrix represents a portion 72 in which the three primary colors of R, G, and B overlap with each other by a mask pattern during exposure, that is, a portion 72 in which both red and cyan colors are exposed and developed into black. As can be seen from the drawings, it can be seen that the three primary colors R, G, and B 60 and the black black matrix 72 formed by performing three exposures with one photomask are formed at the same height.

Here, the exposure is performed by 5: 1 using a stepper, and the exposure is performed for each part according to the screen size.

After exposure, it is immediately deposited on the developer, and color development occurs. After development, fixing and drying process do not form a protective layer (TOP COAT) directly on the R, G, B pattern film and the black black matrix. OXIDE) The transparent electrode film 71 can be formed by sputtering to complete the color filter structure according to the present invention as shown in FIG.

The color filter of the delta type according to the present invention of the active matrix method using TFT (THIN FILM TRANSISTOR) and MIM (METAL INSULATOR METAL) is a photomask (or reticle) as shown in FIG. Using a medium, red and cyan are respectively exposed to obtain a color array as shown in FIG. 3 (e).

In the same way, the MOAIC TYPE and the STRIPE TYPE used for STN LCDs also differ in the pattern arrangement of the photomask, and R, G, B patterns and black matrices can be obtained with one reticle.

[Effects of the Invention]

As described above, according to the present invention, the three primary colors of the same height are formed by performing three exposures, respectively, by moving a plurality of portions with a stepper using a single photomask using the principle of positive color photographing. At the same time, since the black black matrix, in which the R, G, and B primary colors are all exposed, is formed at the same height as the R, G, and B primary colors, conventional red, green, and blue resists (RESIST) are not required. The elimination of the chrome sputter process to simplify the process and avoid the mixing of color 3 eliminates the pinhole problem of chromium, and eliminates the need for a protective layer, which accounts for 15% of the color filter price, and requires surface smoothness like STN LCD. It can be applied to the display device, and the light transmittance (20-30%) of the existing color filter can be improved to about 10%.

Claims (9)

In order to prevent deterioration of the thin film transistor on the substrate, the same height is formed at predetermined intervals, and a plurality of black matrices made of positive photoresist and the black matrix are separated from the black matrix at the same height, respectively, and are sequentially formed. And a R, G, B color filter layer made of a positive photoresist, and the black matrix formed at the same height and a transparent electrode film coated on the color filter layer. The color filter of claim 1, wherein the substrate is formed of glass, quartz, or a polymer film. The color filter of claim 1 or 2, wherein the black matrix is formed of portions in which all three primary colors of R, G, and B are exposed to overlap the three primary colors. The color filter layer and the R, G, B color filter layer are formed between the R, G, B color filter layers sequentially while forming the R, G, B color filter layers sequentially at the same height with each other through exposure and development using a photomask on a substrate coated with a positive color photosensitive liquid. Forming a black matrix at a predetermined interval to prevent deterioration of the thin film transistor at the same height, and forming a transparent electrode film on the flattened black matrix and the color filter layer. . The method of claim 4, wherein the color filter for the LCD is manufactured using the color development principle of the positive color photosensitive material. The method of claim 4, wherein the photomask is patterned with a chrome pattern on a quartz substrate, and the mask pattern is successively arranged in a form in which two chrome patterns successively spaced at a predetermined interval and a width of the chrome pattern are re-floating. Method of manufacturing a color filter for LCD, characterized in that the. 5. The red pattern of claim 4, wherein the R, G, B color filter layer and the black matrix are exposed on the substrate to which the positive color photoresist is applied using a single photomask while moving various portions with a stepper according to the screen size. After the phosphorus R color filter layer was formed, the stepper was moved and exposed again in the same manner as in the above manufacturing process to form G and B color filter layers, which are green patterns and blue patterns, and red, green color by the mask pattern during exposure. And all of the blue color is exposed, and a black matrix, which is a part showing black color, is formed at the same time. The method of manufacturing a color filter for an LCD according to claim 4 or 7, wherein the exposure is performed with visible light to form the color filter layer. The method of claim 4, wherein the substrate coated with the positive color photoresist is deposited and developed in a developing solution immediately after exposure, and then formed through a fixing process and a drying process.