JP2000028815A - Production of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain color filters having high flatness of color filter layers while having resin black matrices which are high in light shieldability. SOLUTION: After a first BM(black matrix) layer 104 is formed, the color filter layer 107 is formed. The second BM layer 110 is then formed in the position superposed on the first BM layer 104. The color filters are obtd. by forming the black matrices(BMs) of at least two layers, forming the color filter layer after the formation of the first black matrix layer, then forming the second black matrix layer in the position superposed on the first black matrix layer and, therefore, the adequate hue corresponding to image signals and sufficient color densities are obtd. at the time of combining the color filter with an optical shutter function of liquid crystals. The excellent display contrast with the sufficiently high light shieldability of the black matrices may be obtd. and the flatness of the color filter layer is improved. The pattern collapse at the time of forming the black matrices may be prevented as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter having a resin black matrix having a high light-shielding property and a high flatness of a color filter layer.

[0002]

2. Description of the Related Art Generally, a color filter for a liquid crystal display element is composed of R (red), G (color) formed close to a glass substrate.
It is composed of a large number of pixels each of which has three primary color pixels (green) and B (blue). Further, a black matrix, which is a light-shielding region having a certain width, is provided between each pixel in order to increase display contrast.

Many of the black matrices used in conventional color filters are made of a metal thin film of Cr, Ni, Al or the like on which a fine pattern is formed in advance by a photolithography method. As a method for forming the metal thin film, a vacuum thin film forming method such as a sputtering method or a vacuum evaporation method is widely used. In order to form a fine pattern on the metal thin film, a photoresist pattern is usually formed by a photolithography method, and then the metal thin film is etched using the photoresist as an etching mask.
By this step, a fine pattern of the metal thin film that matches the fine pattern of the photoresist can be formed.

As a method of forming pixels of a color filter, a method of dyeing a dyeable film formed by photolithography, a method of using a photosensitive pigment dispersion composition, a method of non-photosensitive pigment dispersion composition In addition to an etching method, an electrodeposition method using a patterned electrode, a method of forming a colored portion by a printing method or an inkjet method is also known as a low-cost manufacturing method.

In recent years, instead of a metal thin film, a resin containing a light-shielding agent is patterned to form a black matrix, and pixels are formed thereon to form a color filter for the purpose of environmental friendliness and low cost. A manufacturing method has been proposed (for example, JP-A-2-239204).
Generally, a black matrix obtained by patterning a resin containing a light-blocking agent is called a resin black matrix. Hereinafter, the resin black matrix is referred to as “BM”.
Abbreviated.

An example of a conventional method for manufacturing a color filter using the BM is shown in FIGS. FIG.
6A, a BM photoresist including a light-shielding agent is applied on a glass substrate 301 to form a BM resist layer 3.
03 is formed, and is irradiated with ultraviolet rays UV through the BM photomask 302, and is developed, as shown in FIG.
An M layer 304 is formed. Next, as shown in FIG.
An operation of applying a color photoresist for a color filter on the BM to form a color resist layer 306 and irradiating and developing ultraviolet UV through the color filter layer mask 305 for R, G, and B colors is repeated, FIG.
As shown in (d), the color filter layer 3 as a pixel
07 is manufactured.

[0007]

Generally, in a color filter, uniformity of transmitted light is extremely important.
For this reason, it is desired that the color filter layer 307 be formed as flat as possible. On the other hand, in order to increase the display contrast of each pixel, a high light-shielding property is required for the BM. For example, an optical density value (OD value) required for the BM
Is 3 or more. As a method of giving a high OD value to the BM, a method of increasing the content of the light-blocking agent in the BM,
A possible method is to increase the thickness of the BM layer.

[0008] Among them, the method of increasing the content of the light-shielding agent extremely lowers the adhesion to the substrate 301. It is considered that this is because an increase in the amount of the light-shielding agent component that does not contribute to the adhesion to the substrate reduces the adhesive area between the resin and the substrate. When the adhesion between the substrate 301 and the BM layer 304 is reduced, there is a problem that peeling occurs during patterning of the BM or in a post-process, particularly in a process requiring heat treatment at a high temperature. For this reason, the BM layer 3 is generally unavoidable.
The method of increasing the thickness of the film 04 is adopted. However,
As shown in FIG. 5, in order to obtain a light-shielding characteristic with an optical density value of 3 or more required for the BM, as shown in FIG.
m, which is a metal thin film (1000Å
Å2000 °), which is nearly ten times thicker.

However, if the thickness of the BM layer 304 is increased to about 1 μm to 1.5 μm in order to obtain an optical density required for the BM, as shown in FIG. Since the film thickness of the color filter layer 307 to be formed is also about 1 μm to 1.5 μm, the total film thickness of the overlapping portion is much larger than other portions, and the flatness of the color filter layer 307 as a whole is reduced. The problem of significant damage occurs.

In addition, if the thickness of the BM layer 304 is increased, the light-shielding property is naturally increased, so that it is difficult for light to reach the deep portion of the film during the exposure for forming the BM, and as shown in FIG. The allowable range of the developing time is narrowed, and B
There is a problem that the M pattern is lost. As a method for avoiding this, for example, Japanese Patent Application Nos. Hei 6-331816, Hei 9-297209, Hei 6-324.
No. 207 is disclosed, but these are effective for forming a highly light-shielding BM layer without erosion, but have no effect for the purpose of improving the flatness of a color filter layer. Could not be obtained. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and accordingly, an object of the present invention is to provide a method for manufacturing a color filter which forms a highly light-shielding BM and ensures the flatness of a color filter layer. To provide.

[0011]

According to the present invention, there is provided a color filter having a resin black matrix (BM) formed of at least two layers. A method for manufacturing a color filter is provided, in which a color filter layer is formed after forming a BM layer, and then a second BM layer is formed at a position overlapping the first BM layer. In the above, according to the present invention, a first BM layer is formed on one surface of a glass substrate;
Form a color filter layer so that the layer and the peripheral part overlap,
Next, a photoresist layer for a second BM layer is formed thereon, and a method for manufacturing a color filter is provided, in which the photoresist layer is exposed through a photomask to form a second BM layer. The present invention also provides a method for producing a color filter in which, after forming a photoresist layer for a second BM layer, the photoresist layer is exposed from the back side of a glass substrate to form a second BM layer. I do. In the above, it is preferable that the optical density values (OD values) of the first and second BM layers both fall within the range of 1-2.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the accompanying drawings. (Embodiment 1) FIGS. 1A to 1F are process diagrams sequentially showing Embodiment 1 of the present invention. In the first step shown in FIG. 1A, a negative type is formed on a glass substrate 101 which has been subjected to a pretreatment such as washing with pure water and / or a surfactant aqueous solution using a spin coater, a slit coater, a roll coater or the like. A first BM photoresist is applied uniformly over the entire surface to form a first BM resist layer 103. Next, a photomask 102 for the first BM on which a predetermined pattern is formed is arranged at a predetermined position, and ultraviolet rays UV are irradiated from above the photomask 102. Next, the exposed first BM resist layer 103 is developed with an inorganic or organic alkaline developing solution and baked to form a first patterned BM having a predetermined pattern as shown in FIG. The BM layer 104 is obtained. The first BM layer 104 has a thickness of about 0.5 μm and is adjusted so that the optical density value (OD value) is in the range of 1-2.

In the second step shown in FIG. 1C, R (red), G (green), B
A negative colored photoresist for a color filter containing any one of the colors (blue) is uniformly applied using a spin coater, a slit coater, a roll coater, or the like to form a colored resist layer 106. Next, a photomask 105 for a color layer on which a predetermined pattern is formed is arranged at a predetermined position, ultraviolet rays are irradiated from above the photomask, and then developed with an inorganic or organic alkaline developer and baked. To form a color filter layer of one color. The thickness of this color filter layer is about 1 μm. By repeating this operation using a negative-colored photoresist of another color, as shown in FIG. 1D, a color filter layer 107 in which three color filters are arranged close to each other on a plane is formed. It is formed. At this time, there is no particular limitation on the order of applying the R, G, and B colored photoresists.

Next, in a third step shown in FIG.
Using a spin coater, a slit coater, a roll coater, or the like, a negative type second BM photoresist is uniformly applied on the entire surface to form a second BM resist layer 109. Next, a photomask 1 for the second BM on which a predetermined pattern is formed
08 at a predetermined position, and the photomask 102
UV light is irradiated from above. The exposed second BM resist layer 109 is developed with an inorganic or organic alkaline developer and baked to form a second BM layer 110 on which a predetermined pattern is formed as shown in FIG. Get. The second BM layer 110 has a thickness of about 0.5 μm and is adjusted so that the optical density value (OD value) is in the range of 1-2. The second BM layer 110 is formed so as to overlap with the first BM layer 104 at least at the center by adjusting the pattern and arrangement of the photomask. According to the manufacturing method of the first embodiment described above, FIG.
As shown in a cross-sectional view of one pixel in (a), the color filter 100 in which the BM 111 is formed by the upper and lower BM layers 104 and 110 can be manufactured. In addition,
In the first embodiment, an example in which a negative type photoresist is used has been described. However, a positive type photoresist may be used.

As shown in FIG. 3A, the color filter 100 manufactured according to the first embodiment has R, G, B
Each of the three color filter layers 107 has a thickness of about 1 μm.
When combined with the liquid crystal light shutter function, light corresponding to an image signal can be transmitted with a suitable hue and a sufficient color density.

The peripheral portion of each color filter layer 107 is surrounded by a BM 111. Each BM 111 has a thickness of about 0.5 μm and an optical density value (OD value) of 1.
, The total film thickness is about 1 μm.
m, the optical density value (OD value) is in the range of 2 to 4 and the light shielding property is sufficiently high, and the display contrast of the obtained color filter is improved.

In the color filter manufactured by the conventional manufacturing method shown in FIG. 3C, the step t3 between the center and the periphery of the color filter layer 307 is different from that of the BM layer 30.
4 is 1 μm or more depending on the film thickness of No. 4 and the flatness of the color filter layer 307 is significantly impaired.
In the color filter 100 according to the first embodiment shown in FIG. 5A, the thickness of the first BM layer 104 is about 0.5 μm, so that the step t1 in the color filter layer 107 is only about 0.5 μm. The flatness of the filter layer 107 is significantly improved. Therefore, an additional film forming operation such as an overcoat which has been conventionally performed to correct the distortion of the flatness becomes unnecessary or can be simplified.

Further, in the manufacturing method of the present invention shown in the first embodiment, since the optical density values (OD values) of the first and second BM layers 104 and 110 are within the range of 1 to 2, respectively. As shown in FIG. 6, in the exposure and development when forming the BM layer, there is an advantage that the allowable range of the development time is much larger than that of the conventional method, and that pattern collapse due to loss or the like during development does not occur. is there.

(Embodiment 2) Next, another embodiment of the present invention will be described. 2A to 2F are process diagrams sequentially showing Example 2 of the present invention. The first shown in FIG.
In the process, a glass substrate 2 treated in the same manner as in Example 1
, A negative type first BM photoresist is uniformly applied on the entire surface in the same manner as in Example 1 to form a first BM resist layer 203, and then a first BM on which a predetermined pattern is formed A photomask 202 is disposed at a predetermined position, and ultraviolet rays UV are irradiated from above the photomask 202. Next, the exposed first BM resist layer 203 is developed and baked to obtain a first BM layer 204 on which a predetermined pattern is formed as shown in FIG. This first BM
The layer 204 has a thickness of about 0.5 μm and is adjusted so that the optical density value (OD value) is in the range of 1 to 2.

In the second step shown in FIG. 2C, R, G, and B are formed on the first BM layer 204 in the same manner as in the first embodiment.
Is uniformly applied over the entire surface to form a colored resist layer 206. Next, a color layer photomask 20 on which a predetermined pattern is formed
5 is arranged at a predetermined position, and is irradiated with ultraviolet rays UV from above the photomask, developed, and baked to form a color filter layer of one color. The thickness of this color filter layer is about 1
μm. By repeating this operation using a negative-colored photoresist of another color, as shown in FIG. 2D, a color filter layer 207 in which three color filters are arranged close to each other on a plane is formed. It is formed. At this time, there is no particular limitation on the order of applying the R, G, and B colored photoresists.

Next, in a third step shown in FIG.
Using a spin coater, a slit coater, a roll coater, or the like, a positive type second BM photoresist is uniformly applied over the entire surface to form a second BM resist layer 209. Next, in Example 2, the second BM resist layer 209 was used.
Is exposed from the back side of the glass substrate 201, developed with an inorganic or organic alkaline developer, and baked to form a second BM layer 210 as shown in FIG. 2nd BM
Exposure of the first resist layer 209
4 performs the function of a photomask, so that the second BM layer 210 overlapping the pattern of the first BM layer 204 can be formed without using a separate photomask by self-alignment.
Is formed. The formed second BM layer 210 has a thickness of about 0.5 μm and is adjusted so that the optical density value (OD value) is in the range of 1-2. Example 2
The negative type photoresist used for forming the first BM layer 204 may be of a positive type.

As shown in FIG. 3B, the color filter 200 manufactured according to the second embodiment has R, G, B
Each of the three color filter layers 207 has a thickness of about 1 μm.
When combined with the optical shutter function of the liquid crystal, a suitable hue corresponding to the image signal and a sufficient color density are obtained, and the BM 211 has a thickness of about 0.5 μm.
The first and second BM layers 204 and 210 have a total film thickness of about 1 μm, an optical density value (OD value) in the range of 2 to 4, and a sufficiently high light-shielding property. And excellent display contrast can be obtained.

Further, as shown in FIG. 3B, the step t2 which affects the flatness of the color filter layer 207 depends only on the thickness of the first BM layer 204. The flatness is high, overcoating or the like for correcting flatness is unnecessary or simplified, and the optical density values (OD values) of the first and second BM layers 204 and 210 are each within the range of 1-2. Because each BM
Pattern collapse does not occur during exposure and development when forming the layer.

[0024]

The method for manufacturing a color filter according to the present invention comprises:
A black matrix (BM) is formed from at least two layers, a color filter layer is formed after forming a first black matrix layer, and then a second black matrix layer is formed at a position overlapping the first black matrix layer. When combined with the optical shutter function of the liquid crystal, a suitable hue and a sufficient color density corresponding to the image signal are obtained, and the light shielding property of the black matrix is sufficiently high and excellent display contrast is obtained. The flatness of the color filter layer is improved, and the pattern collapse during the formation of the black matrix can be prevented.

[Brief description of the drawings]

FIG. 1 is a process chart showing one embodiment of the present invention in the order of (a) to (f).

FIG. 2 is a process chart showing another embodiment of the present invention in the order of (a) to (f).

3A is a cross-sectional view of a color filter manufactured according to one embodiment of the present invention, FIG. 3B is a cross-sectional view of a color filter manufactured according to another embodiment of the present invention, and FIG. )
Is a cross-sectional view of a color filter manufactured by a conventional manufacturing method.

FIG. 4 is a process chart showing an example of a conventional color filter manufacturing method in the order of (a) to (d).

FIG. 5 is a graph showing a relationship between a film thickness of a black matrix (BM) and an optical density value (OD value).

FIG. 6 is a graph showing a relationship between an optical density value (OD value) and a developing time when a black matrix (BM) is formed.

[Explanation of symbols]

 100: Color filter 101: Glass substrate 102: First BM photomask 103: First BM resist layer 104: First BM (black matrix) layer 105: Color layer photomask 106: Colored resist layer 107: Color filter Layer 108: Photomask for second BM 109: Resist layer for second BM 110: Second BM (black matrix) layer 200: Color filter 201: Glass substrate 202: Photomask for first BM 203: Resist for first BM Layer 204: First BM (black matrix) layer 205: Photomask for color layer 206: Colored resist layer 207: Color filter layer 209: Resist layer for second BM 210: Second BM (black matrix) layer

Claims (4)

[Claims] When manufacturing a color filter having a resin black matrix, the black matrix is formed from at least two layers, a color filter layer is formed after forming a first black matrix layer, and then the first black matrix layer is formed. Forming a second black matrix layer at a position overlapping the black matrix layer. 2. In the above, a first black matrix layer is formed on one surface of a glass substrate, and a color filter layer is formed so that the first black matrix layer and a peripheral portion overlap with each other. The color according to claim 1, wherein a photoresist layer for a second black matrix layer is formed, and a second black matrix layer is formed by exposing the photoresist layer through a photomask. Manufacturing method of filter. 3. The method according to claim 1, wherein a first black matrix layer is formed on one surface of the glass substrate, a color filter layer is formed such that the first black matrix layer overlaps a peripheral portion, and then a first black matrix layer is formed on the first black matrix layer. The color filter according to claim 1, wherein a photoresist layer for a second black matrix layer is formed, and the photoresist layer is exposed from the back side of the glass substrate to form a second black matrix layer. Manufacturing method. 4. An optical density value (OD value) of each of the first and second black matrix layers is within a range of 1 to 2. 3. The method for producing a color filter according to item 1.