JPH08234014A - Production of color filter and color filter substrate used for the same - Google Patents

Abstract

PURPOSE: To enhance production efficiency by speeding up the alignment of a photomask substrate and a color filter substrate. CONSTITUTION: The photomask substrate 20 formed with first alignment marks of a wedge type and the color filter substrate 10 formed with second alignment marks of a wedge type are used at the time of producing the color filters by successively aligning patterns of respective colored pixels of red, green and blue on the color filter substrate 10. The alignment of the photomask substrate 20 and the color filter substrate 10 is executed by these first and second alignment marks. The position relations of the alignment marks on the respective substrates 10, 20 is rapidly recognized only by detection on one line and the time required for the alignment is shortened. The alignment marks of the wedge type are reversed in case the directions or front and rear of the substrates 10, 20 are mistaken and, therefore, the easy discovery of the mistakes in setting is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a color filter for a liquid crystal display, and more specifically, a pattern of a light shielding layer in the color filter and red (R), green (G) and blue (B). The present invention relates to a method of manufacturing a color filter for sequentially forming a pattern of each of the colored pixels and a color filter substrate used therefor.

[0002]

2. Description of the Related Art The structure of a general color filter used in a liquid crystal display is as shown in the sectional view of FIG. 1. This color filter is a thin film of chromium or the like on a substrate 1 of glass, plastic or the like. After the pattern of the light-shielding layer 2 is formed by, the pattern of the fine colored pixels 3 of three colors of R, G, B is sequentially and repeatedly formed, and the protective film 4 is further provided thereon, and the transparent electrode 5 is made of ITO. It is manufactured by forming a film. Then, as a method of forming the three colored pixels 3 in this color filter, there are a dyeing method, a pigment dispersion method, a printing method, an electrodeposition method, a transfer method and the like. In any method, the light shielding layer 2 is formed. It is necessary to align the patterns with each other in the process of sequentially forming each colored pixel 3 on the formed substrate 1.

As one of the methods for performing this alignment,
For example, there is one described in JP-A-4-333018. In this method, "well" -shaped mask marks are written in two appropriate places on the photomask substrate, and "+" marks are placed on the color filter substrate at positions corresponding to each mask mark.
The substrate mark of "++" shape is written and the alignment in the X and Y directions is performed with respect to the two marks so that the alignment of each colored pixel with the pattern is performed.

[0004]

In the alignment method described in the prior art, the substrate mark provided on the color filter substrate is set to the center point of the mask mark provided on the photomask substrate also used for three colors. Since the corresponding three points are aligned with each other for alignment, there is an advantage that there is no fear of misunderstanding of each color and the alignment of the colored pixels of each color can be surely performed, but for alignment, X and Y are used. Since it is necessary to detect on the two lines in the direction by the sensor, there is a problem that the detection time is long and the alignment cannot be performed quickly. In addition, usually, this kind of substrate mark is formed at the same time when the pattern of the light shielding layer is formed, but when a coloring material such as a colored photosensitive material is applied or transferred, the coloring material is also formed on the substrate mark. There is also a problem in that it is difficult to detect the substrate mark due to coating or transfer.

The present invention has been made in view of the above problems, and an object of the present invention is to speed up the alignment between the photomask substrate and the color filter substrate to improve the manufacturing efficiency. It is an object of the present invention to provide a method of manufacturing a color filter that can be used, and also to provide a color filter substrate used in the manufacturing method.

[0006]

In order to achieve the above-mentioned object, a method of manufacturing a color filter according to the present invention comprises a color filter substrate on which a pattern of a light-shielding layer is formed.
In a method of manufacturing a color filter by sequentially aligning and forming patterns of blue colored pixels,
Using a photomask substrate having a wedge-shaped first alignment mark and a color filter substrate having a wedge-shaped second alignment mark, the photomask is formed by the first alignment mark and the second alignment mark. It is characterized in that the substrate and the color filter substrate are aligned with each other.

Then, the second alignment mark on the color filter substrate is formed at the same time when the pattern of the light shielding layer is formed, and the pattern of each colored pixel is formed in a region where the second alignment mark is not formed. Is preferred.

Further, the color filter substrate used in the above manufacturing method is a color filter substrate provided with a second alignment mark for alignment used when forming a pattern of each colored pixel of red, green and blue. The second alignment mark is a wedge-shaped alignment mark formed corresponding to the wedge-shaped first alignment mark formed on the photomask substrate.

It is preferable that the second alignment mark is formed at the same time as the formation of the pattern of the light shielding layer, and is formed beside the pattern portion where the pattern of each colored pixel is formed.

[0010]

In the method of manufacturing the color filter having the above-mentioned structure, since the wedge-shaped alignment mark is used for the alignment between the photomask substrate and the color filter substrate,
The positional relationship of each alignment mark can be recognized by the detection on one line. In addition, when the photomask substrate and the color filter substrate are misaligned in direction or front and back, the wedge-shaped alignment marks are reversed, so that setting mistakes between the two can be prevented. Then, by forming the pattern of each colored pixel in the region where the second alignment mark is not formed on the color filter substrate, the coloring material does not come into contact with the alignment mark, which facilitates detection.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a plan view showing a color filter substrate on which wedge-shaped alignment marks are formed.

The color filter substrate 10 has a rectangular shape (350 mm × 300 mm) as viewed from above and has a thickness of 0.7.
mm, and the material is glass. At the center of the substrate 10, a pattern portion 11 composed of a light-shielding layer and R, G, and B colored pixels is provided on the upper and lower sides to form two surfaces. The pattern portion 11 is first formed through a pattern forming step of the light shielding layer, a step of forming a blue colored pixel pattern, a step of forming a green colored pixel pattern, and a step of forming a red colored pixel pattern. The pattern of each colored pixel is 100μ
m intervals.

An alignment mark region 12 (generally 12 mm × 4 mm) is provided on both sides of the pattern portion 11 on the periphery of the color filter substrate 10, and this region 12 (only the right side is shown) is provided. Three wedge-shaped alignment marks are formed of the same material as the light-shielding layer. The line widths of the diagonal line and the horizontal line of the alignment mark are 50 μm, respectively. The diagonal lines are horizontal and 45
The length of the diagonal line is 2.1 mm and the length of the horizontal line is 1.5 mm. This alignment mark has the alignment mark area 12 in the positional relationship shown in FIG.
Are spaced apart by about 3.75 mm.
Then, in the vicinity of these alignment marks, in order to show how many colors each alignment mark is used for aligning colored pixel patterns, in order to indicate the colors of blue, green and red, “b”, Symbols such as "g" and "r" are provided. The light-shielding layer is called a black matrix, and is mainly formed of chrome, and the alignment mark is also formed of chrome at the same time. The chromium layer has a thickness of 0.05 μm to 0.2 μm.

In this embodiment, the alignment mark areas 12 are provided on both sides of the pattern portion 11, but the R, G, and B colored pixels of the color filter are aligned with the light shielding layer (alignment, registration). It is preferable to provide a large number around the color filter substrate 10. Further, in this embodiment, the pattern portion 11 of the color filter is provided on two sides, but FIG.
One surface having a color filter pattern portion 11 in the center of the color filter substrate 10 as shown in FIG. 3A, and the pattern portion 11 near four corners as shown in FIG. 3B.
There are 4 imposition etc. Here, in any imposition, as shown in the drawing, the alignment mark regions 12 may be provided on both sides of the pattern portion 11 or may be provided in a large number around. The color filter substrate 10 has a size of 320 mm ×
There are 300 mm, 400 mm × 300 mm, etc., and the thickness is 1.1 mm.

Next, a pattern transfer photomask substrate used in the step of forming a colored pixel pattern on the color filter substrate 10 will be described. FIG. 4 is a plan view for explaining this photomask substrate.

As shown in FIG. 4, the photomask substrate 2
0 is provided with pattern portions 21 in two upper and lower stages,
Alignment mark areas 22 (only the right side is shown) are provided on both sides thereof. Then, in the alignment mark region 22, wedge-shaped alignment marks are formed in the positional relationship shown in FIG. 4 so as to correspond in order to the wedge-shaped alignment marks formed on the color filter substrate 10 of FIG. There is. That is, a wedge-shaped mark for blue for the first color is arranged above the alignment mark region 22, a wedge-shaped mark for green for the second color is arranged at the center, and a red wedge for the third color is arranged at the bottom. A wedge-shaped mark is placed. The alignment mark has the same shape and size as the wedge-shaped alignment mark provided on the color filter substrate. Further, symbols such as "B", "G", "R", etc. are provided in the vicinity of each alignment mark as symbols indicating the respective colors. These symbols may be formed so that they can be seen side by side with the symbols of the color filter substrate 10 when they are aligned, or they may be overlapped. Note that the allowable amount of alignment is about ± 30 μm, but in reality it is preferably less than that, and for this purpose, the line width needs to be made even thinner.

As described above, the wedge-shaped marks for the R, G, and B colored pixels on the photomask substrate 20 and the wedge-shaped marks on the color filter substrate 10 corresponding to the respective colors are located below the alignment mark area. And the central part and the upper part are overlapped with each other. Furthermore, since the alignment mark is a wedge-shaped mark composed of diagonal lines and horizontal lines, the color filter substrate 1
When the front and back of 0 and the front and back are mistaken, the error can be easily checked, which facilitates visual inspection after automatic alignment. Further, by providing a symbol corresponding to each color in the vicinity of the wedge-shaped mark for each R, G, B colored pixel, the efficiency of visual confirmation is improved. It should be noted that other symbols corresponding to the respective colors may be used in the vicinity of the alignment mark instead of the symbols. Of course, the symbol at this time may be one that can be easily recognized at the time of visual confirmation.

Next, the manufacturing method of the color filter of the present invention will be described with reference to the process chart of FIG. As described above, the color filter manufacturing method includes a dyeing method, a pigment dispersion method, a printing method, an electrodeposition method, a transfer method and the like, and the manufacturing method of the present invention can be applied to all of these manufacturing methods. A case where a mosaic type color filter pattern is formed by a manufacturing process using a dispersion method will be described as an example.

First, in step 1, the glass substrate is washed. Then, after forming a chromium film in step 2, the chromium thin film is processed in step 3 to form a light shielding layer pattern. At this time, a wedge-shaped alignment mark made of the same material as the light-shielding layer is also formed at the same time.
Process to form the bottom, center, and top of the. As a result, the color filter substrate 10 shown in FIG. 2 in which only the light shielding layer is formed on the pattern portion 11 is completed. That is, the substrate is completed without the R, G, and B colored pixel patterns.

Subsequently, in step 4, a first color blue (B) colored resist is applied. Here, die head coating or the like is performed so that the colored resist is not applied to the alignment mark region 12 on the color filter substrate 10. In this way, since the colored resist is not applied on the alignment mark, it becomes easy to process the image data input from the CCD camera during the alignment process in step 6 described below. That is, since the colored resist has three colors and the alignment mark is formed of the same material as the light-shielding layer, three types of slice level settings were required. There is a merit that only one type of detection is required. Then, in step 5, the color filter substrate is pre-baked (dried) to evaporate only the solvent.

The alignment in step 6 will be described with reference to FIG. The photomask substrate 20 shown in FIG. 4 is superposed on the color filter substrate 10 with an interval of 50 μm therebetween so that the alignment marks substantially overlap each other. These substrates 10 and 20 are held by adjustable holders (not shown).
Further, a CCD camera 6 having an area sensor of about 250,000 pixels and two light sources 7, 7 are installed above the alignment mark areas 12, 22 so that the alignment mark can be monitored. First, the camera 6 performs a general alignment by photographing an area of 12 mm × 12 mm (an area of 24 μm × 24 μm per pixel) covering the alignment mark areas 12 and 22. That is, the holders of the substrates 10 and 20 are adjusted so that the three sets of wedge-shaped alignment marks have a predetermined positional relationship. Next, camera 6
Takes a set of alignment marks for blue arranged below the alignment mark areas 12 and 22. The input area of the camera 6 at this time is 3.5 mm × 3.5 mm, and an area of 7 μm × 7 μm is photographed per pixel. Then, the holder is moved and adjusted for precise positioning. Further, when performing high-resolution and high-accuracy alignment, or when reducing the line width and the size of the mark, a sensor with a large number of pixels in the area sensor is used, or a CCD camera in which a plurality of area sensors are arranged is used. You can use it. Of course, it is necessary to increase the image memory etc. according to these data.

After the color filter substrate 10 and the photomask substrate 20 are aligned with each other, the first step is performed in step 7.
The colored pixel pattern of color is exposed on the pattern portion 11 of the color filter substrate 10. Subsequently, in step 8, these are developed to remove the pattern of unnecessary areas which are not exposed. Then, in step 9, post-baking hardens the exposed pattern.

Further, the above steps 4 to 9 are repeated by using a colored resist of green (G) as the second color and red (R) as the third color. here,
The alignment mark arranged in the center of the alignment mark regions 12 and 22 is used for alignment in the second color forming step, and the alignment mark arranged below is used for alignment in the third color forming step. I do.

The photomask substrate 2 used above
0 is the one shown in FIG. 4, and is used when one sheet also serves three colors. When a different photomask substrate is used for each color, the photomask substrate 20 having an alignment mark for one color may be used as illustrated in FIG.

Here, the alignment performed in step 6 will be described in detail, first with reference to FIGS. 8 to 11, and then with reference to FIG.

8 to 11 show the basic layouts of the colored pixel patterns in the color filter. As can be seen from these, the patterns of FIGS.
A single photomask substrate can be used by using a photomask substrate having a larger size for each two pixels in the vertical direction as the G / B combined pattern. this is,
After forming the first color (blue), the photomask substrate may be shifted by one pixel to form the second color (green), and the photomask substrate may be further shifted by another pixel to form the third color (red). Because. In addition, the pattern of FIG. 11 cannot be used also as a pattern for green, so it is necessary to prepare separately. In this case, alignment marks may be provided as shown in FIG. 7, and patterns for red and blue are vertically arranged. The photomask substrate formed to have a larger size for each pixel may be used as the photomask substrate. By forming in this way, the number of exposure masks can be reduced.

FIG. 12A shows the alignment mark area 1 from the CCD camera 6 after the color filter substrate 10 of FIG. 2 and the photomask substrate 20 of FIG. 4 are overlapped as shown in FIG.
2 and 22 show a state in which the whole is viewed. When the alignment marks are visible as shown in the figure, both substrates 10,
It can be confirmed that 20 is almost matched. of course,
The photomask substrate 20 is shown as its positional relationship in the figure so that one photomask substrate 20 can also be used for three colors.
The alignment marks on the side are shifted by one pixel.
By aligning the offset alignment marks for each color in step 6, each color is formed at a predetermined position.

When forming the colored pixel pattern of the first color (blue), with respect to the alignment mark (b) of the first color among the wedge-shaped alignment marks formed on the color filter substrate 10, The wedge-shaped alignment mark (B) formed on the photomask substrate 20 for each color is aligned with a predetermined position. If it is normal here, the second color (green) alignment mark (g)
And (G) are displaced by one pixel, and the alignment marks (r) and (R) of the third color (red) are displaced by two pixels.
The image is as shown in FIG.

FIG. 12B shows the CCD during the alignment operation.
FIG. 6 is a view of the alignment mark areas 12 and 22 seen from the camera 6, which is a mark position in a normal state in which no positional deviation occurs. At this time, a ₁ = b ₁ and L ₁ = 2.
It is 0 mm (predetermined value). However, an allowable value of about ± 30 μm is set.

FIG. 12 (c) shows a state in which a positional deviation has occurred. At this time, a ₂ = b ₂ ± c and L ₂ = L ₁
(2.0 mm) ± d. These deviations c and d are ±
If it is 30 μm or more, the position of the color filter substrate 10 is adjusted so as to be ± 30 μm or less. Then, an image is input again from the CCD camera 6 and the above processing is repeated until the normal state is reached. Here, d represents the amount of deviation in the vertical direction. Further, c corresponds to the amount of deviation in the horizontal direction. That is, since the angle of the wedge is 45 degrees, it is possible to uniquely obtain the deviation in the lateral direction from c. If another angle is set, the calculation according to the angle may be performed. Although the position of the color filter substrate is adjusted here, the position of the photomask substrate may be adjusted.

Here, the conveying direction of the color filter substrate 10 and the front and back are reversed, or the photomask substrate 20 is used.
If the setting position or the front and back are reversed, the alignment mark on the color filter substrate 10 side and the alignment mark on the photomask substrate 20 side are in opposite directions.
This makes it possible to confirm that the settings of the color filter substrate 10 and the photomask substrate 20 are defective.

[0033]

As described above, according to the method of manufacturing a color filter of the present invention, since the wedge-shaped alignment mark is used for aligning the photomask substrate and the color filter substrate, the alignment mark on each substrate is Since the positional relationship can be quickly recognized only by detecting on one line, it is possible to shorten the time required for the alignment and improve the manufacturing efficiency. Also, if the orientation of the photomask substrate and the color filter substrate or the front and back are wrong, the wedge-shaped alignment marks will be reversed, so you can easily find the setting mistake of both and prevent the unnecessary process after that. You can

By forming the pattern of each colored pixel in the area where the alignment mark is not formed on the color filter substrate, the coloring material does not cover the alignment mark, so that the detection can be easily performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a general color filter.

FIG. 2 is a plan view showing a color filter substrate having alignment marks formed thereon.

FIG. 3 is an explanatory diagram showing another example of imposition of pattern portions.

FIG. 4 is a plan view showing a photomask substrate.

FIG. 5 is a process drawing showing a manufacturing process of a color filter.

FIG. 6 is an explanatory diagram showing a specific example of a method of aligning a color filter substrate and a photomask substrate.

FIG. 7 is a plan view showing a G photomask substrate.

FIG. 8 is a pattern layout diagram of colored pixels in a color filter.

FIG. 9 is another pattern layout diagram of the same.

FIG. 10 is another pattern layout diagram of the same.

FIG. 11 is another pattern layout diagram of the same.

FIG. 12 is an explanatory diagram showing an alignment state of a color filter substrate and a photomask substrate.

[Explanation of symbols]

 10 Color Filter Substrate 11 Pattern Part 12 Alignment Mark Area 20 Photomask Substrate 21 Pattern Part 22 Alignment Mark Area

Claims (4)

[Claims] 1. A method of manufacturing a color filter by sequentially aligning and forming patterns of colored pixels of red, green, and blue on a color filter substrate on which a pattern of a light-shielding layer is formed. A photomask substrate on which the first alignment mark is formed and a color filter substrate on which the wedge-shaped second alignment mark is formed are used, and the photomask substrate and the color filter are formed by the first alignment mark and the second alignment mark. A method for manufacturing a color filter, which comprises aligning a substrate. 2. The second alignment mark on the color filter substrate is formed at the same time when the pattern of the light shielding layer is formed, and the pattern of each colored pixel is formed in a region where the second alignment mark is not formed. The method of manufacturing a color filter according to claim 1, wherein 3. A color filter substrate having a second alignment mark for alignment used when forming a pattern of red, green and blue colored pixels, wherein the second alignment mark is a photo film. A color filter substrate, which is a wedge-shaped alignment mark formed corresponding to a wedge-shaped first alignment mark formed on a mask substrate. 4. The second alignment mark is formed at the same time when the pattern of the light shielding layer is formed, and is formed beside a pattern portion where the pattern of each colored pixel is formed. Item 3. A color filter substrate according to item 3.