JP2007093714A - Method for manufacturing color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase surface flatness of a color filter and to improve accuracy of a color filter by suppressing a buildup in an overlapped portion of a black matrix and a color layer. <P>SOLUTION: The method for manufacturing a color filter, after a color layer is applied on a transparent substrate (substrate) W having a black matrix formed thereon, the color layer is subjected to exposure along the pattern of an aperture 7a of a photomask 7 via a projection lens 4b by using a projection exposure device 1 so as to form a colored filter on the transparent substrate W, wherein the projection exposure device 1 is equipped with a light equalization means 4a in the exposure optical system 4, and when exposing the color layer by irradiating the transparent substrate W by the projection lens 4b with exposure light passing through the light equalization means 4a, the distance between the projection lens 4b and the surface of the transparent substrate W to be exposed is shorter or longer by 350 to 700 μm than the focal length of the projection lens 4b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a color filter used for a liquid crystal panel, a plasma display, or the like.

Conventionally, in a method for producing a color filter for a liquid crystal panel, after forming a patterned colored layer on a substrate, a negative photosensitive composition for black matrix is applied to the entire surface, or a black matrix is formed on the substrate. Later, a negative photosensitive composition containing a colorant is applied to the entire surface, and red (R), green (G), and blue (B) colored layers on the substrate are formed using a proxy-mility type exposure apparatus. A color filter manufacturing method is known in which a colored layer pattern separated by a black matrix is arranged on a substrate by performing development after defocus exposure is performed on a portion to be formed (see, for example, Patent Document 1). ).
JP-A-9-159815

In order to prevent the overlapping portion of each colored layer pattern and the black matrix from remaining in a raised state without being sufficiently dissolved and removed by development after exposure, the color filter manufacturing method is usually provided with a proximity gap. By making the defocus exposure to be considerably larger than that of the proximity exposure apparatus, the amount of exposure to the overlapped portion is reduced, and the overlapped portion is easily dissolved and removed by development. An object is to obtain a color filter having excellent flatness.
However, in the color filter manufacturing method, since the proximity exposure apparatus used for this uses a large photomask in the batch exposure method, the photomask is bent by its own weight, thereby exposing the proximity gap. Because the defocus amount varies depending on the exposure area, the defocus exposure cannot be appropriately performed on the entire exposure area as set, and the proximity gap is increased. When there is an error in the parallelism of the light beams of the exposure light, the transfer position shift of the pattern of the opening portion of the photomask to the substrate becomes large, and the accuracy of the color filter may be lowered.

  The present invention has been made in view of the above circumstances, and suppresses the bulge in the overlapping portion between the black matrix and the colored layer as much as possible to improve the surface flatness of the color filter and improve the accuracy of the color filter. An object of the present invention is to provide a method for producing a color filter that can improve the quality.

The present invention is characterized by the following points in order to solve the above problems.
That is, in the color filter manufacturing method according to claim 1, after a colored layer is applied on a substrate on which a black matrix is formed, a pattern of a photomask is exposed to the colored layer through a projection lens using a projection exposure apparatus. In the color filter manufacturing method of forming a colored filter on the substrate,
The projection exposure apparatus includes a light uniformizing unit in an exposure optical system, and the projection lens exposes the colored layer by exposing the substrate with exposure light passing through the light uniforming unit and exposing the colored layer. The exposure is performed at a distance shorter than or longer than the focal length of the projection lens.

  A color filter manufacturing method according to claim 2 is characterized in that, in the color filter manufacturing method according to claim 1, the opening width of the pattern of the photomask is smaller than the width of the opening portion of the black matrix.

  The color filter manufacturing method according to claim 3 is the color filter manufacturing method according to claim 1 or 2, wherein a distance between the projection lens and the surface of the substrate to be exposed is shorter or longer than a focal length of the projection lens. Is 350 μm to 700 μm.

The present invention has the following excellent effects.
According to the color filter manufacturing method of the first aspect, it is possible to expose a wide exposure area by a scanning method using a small photomask without any deflection, and by the light uniformizing means of the exposure optical system. Since the exposure light having a uniform light intensity distribution can be projected on the entire surface of the photomask, the exposure light irradiated on the substrate by the projection lens through the opening of the photomask is spread over the entire exposure region. The defocus amount can be made uniform, and the distribution state of the defocus exposure for the colored layer on the substrate corresponding to the opening of the photomask can be appropriately formed.
In addition, since the pattern of the opening of the photomask is transferred onto the substrate by the projection lens, there is no possibility that transfer deviation of the photomask pattern occurs due to the parallelism error of the light beam of exposure light as in proximity exposure. The pattern of the opening can be transferred onto the substrate with high accuracy.
Therefore, it is possible to suppress the bulge in the overlapping portion between the black matrix and the colored layer as much as possible, to improve the surface flatness of the color filter and to improve the accuracy of the color filter.

  According to the color filter manufacturing method of the second aspect, since the spread of light in the circumferential direction of the opening of the photomask pattern can be increased, the exposure light in the overlapping portion between the black matrix and the colored layer can be increased. The light intensity distribution can be accurately reduced, and the swell amount can be surely kept small.

  According to the color filter manufacturing method of the third aspect, since the defocus amount can be appropriately set, it is possible to reliably control the rising amount in the overlapping portion between the black matrix and the colored layer within the limit value. Thus, the accuracy of the color filter can be further improved.

Hereinafter, a method for manufacturing a color filter according to an embodiment of the present invention will be described.
First, a projection exposure apparatus 1 used when carrying out a color filter manufacturing method according to an embodiment of the present invention will be described with reference to FIGS.
The projection exposure apparatus 1 includes a substrate stage 3 that moves a transparent substrate (substrate) W placed on the upper surface in a Y-axis direction y and an X-axis direction x perpendicular thereto by the operation of the substrate driving means 2, and light uniformity. An optical axis L which is disposed on the exposure unit 5 above the substrate stage 3 with the converting means 4a on the upper side and the projection lens 4b on the lower side and perpendicular to the substrate stage 3 (a plane including the X and Y axes). , An exposure optical system 4, a photomask 7 disposed between the light uniformizing means 4 a and the projection lens 4 b, supported by a mask stage 6, and an illumination optical axis above the photomask 7. And a light source 8 provided so as to coincide with the optical axis L of the optical system 4, and exposure light emitted from the light source 8 through the light uniformizing means 4 a is projected through the opening 7 a of the photomask 7. The substrate W is irradiated by 4b, It is adapted to transfer a pattern of the serial opening 7a on a transparent substrate W.

As is well known in the art, the light homogenizing means 4a emits light with uniform illuminance distribution (light intensity distribution) from the exit surface even when light with uneven illuminance distribution is incident on the incident surface. And an optical lens called a rod lens (rod integrator), a fly-eye lens (fly-eye intector), a kaleidoscope, an optical homogenizer, or the like is used (Japanese Patent Laid-Open No. 5-127086). JP, 7-271052, JP 11-149058, JP 2002-184206, JP 2005-141039, etc.).
As the projection lens 4b, for example, a projection lens having excellent telecentricity can be used on both sides formed by combining five lens groups as described in JP-A-2002-15987.

In addition, the photomask 7 is formed in a rectangular plate shape that is narrow in the transport direction (Y-axis direction y) of the transparent substrate W and long in the X-axis direction x. The rectangular opening 7a is provided. As shown in FIGS. 3 and 4, the size and shape of the pattern of the opening 7a is a light shielding arranged vertically and horizontally in the light shielding layer BMa in the black matrix BM formed on the transparent substrate W of the color filter CF. A width (opening) in the X-axis direction x corresponding to the shape of the rectangular opening BMb (the portion where the red R, green G, and blue B pixels (colored layer) of the color filter are formed) where the layer BMa is not formed The width (h) is set to be slightly smaller than the width (opening width) H of the opening BMb, and the length in the Y-axis direction y is set to be substantially the same as the length N of the opening BMb. Yes.
The distance between the openings 7a of the photomask 7 coincides with the distance in the X-axis direction x of the same pixel of the color filter CF.

  The light source 8 is composed of a lamp such as an ultra-high pressure mercury lamp, and continues to project illumination light until it is turned on when instructed to turn on and instructed to turn off. At least one of the substrate stage 3 and the mask stage 6 is provided so as to be movable and adjustable in a Z-axis direction z (a direction along the optical axis L) perpendicular to the X-axis and Y-axis by a driving unit (not shown). With respect to the focal length of the projection lens 4b fixed in the direction z, the distance between the projection lens 4b and the surface of the transparent substrate W is increased or decreased, so that the distance to the surface of the transparent substrate W is increased. The defocus amount of the projection lens 4b can be adjusted.

Next, an exposure method of the transparent substrate W when manufacturing a color filter using the projection exposure apparatus 1 having the above-described configuration will be described.
After forming a black matrix BM and placing a transparent substrate W coated with, for example, a red R coloring layer (coloring agent) on the black matrix BM, the substrate stage 3 is placed on the X-axis and Y-axis. The exposure start position of the transparent substrate W, for example, the leading opening BMb corresponding to the red R colored layer in the black matrix BM is moved in the axial directions x and y, and the photomask in the exposure unit 5 of the projection exposure apparatus 1 is used. 7 to adjust to the position of the opening 7a. Further, the substrate stage 3 is moved in the Z-axis direction z with respect to the projection lens 4b, and the distance between the projection lens 4b and the transparent substrate W is selected from a predetermined value (350 to 700 μm) from the focal length of the projection lens 4b. The defocus amount f is set by increasing it by a certain value.

  Thereafter, when the substrate stage 3 is moved to one side in the Y-axis direction y (leftward in FIGS. 1 and 2) at a constant speed by the driving means 2 and the light source 8 is turned on, exposure light from the light source 8 is emitted. After the illuminance distribution is made uniform up to the periphery by the light uniformizing means 4a, it is incident on the projection lens 4b through the opening 7a of the photomask 7. The exposure light incident on the projection lens 4b is emitted while keeping the illuminance distribution uniform, and is irradiated on the surface of the transparent substrate W in a defocused state. Irradiation of the exposure light to the transparent substrate W is such that the terminal opening BMb corresponding to the red R colored layer in the black matrix BM is positioned at the position of the opening 7 a of the photomask 7 in the exposure unit 5 of the projection exposure apparatus 1. The light source 8 is turned off, and the movement of the substrate stage 3 is stopped and finished.

  By exposure of the exposure light to the transparent substrate W, the exposure light passes through a plurality of openings 7a arranged in the X-axis direction x in a row in the Y-axis direction y of the photomask 7 (two in the illustrated example). The strip-shaped exposure area A corresponding to the two red R colored layers along the Y-axis direction is exposed. The exposure states of the exposure areas A and A are uniform without any difference between the illuminance distributions of the exposure light passing through the plurality of openings 7a by the light uniformizing means 4a. In the exposure, the width h of the opening 7a of the photomask 7 is formed to be smaller than the width H of the black mask BM. However, when exposure light passes through the opening 7a of the photomask 7, diffraction occurs. By spreading to the periphery of the back side of the opening 7a, the projection lens 4b irradiates the transparent substrate W as it is, so that the illuminance distribution of the exposure light is strong in a wide range at the center of the opening 7a, and its periphery is weak. The defocus exposure is distributed, and the red R colored layer portion applied to the opening BMb of the black matrix BM is sufficiently exposed and applied to the light shielding layer BMa around the opening BMb. Exposure of the colored layer portion is insufficient.

  Therefore, when the transparent substrate W is developed after the exposure, as shown by the solid line in FIG. 4, the exposure is performed with sufficient intensity and the photocuring proceeds in correspondence with the opening BMb of the black matrix BM. On the other hand, a red R colored layer is formed. On the other hand, most of the red R colored layer overlying the light-shielding layer BMa that has not been sufficiently exposed and has not been photocured is dissolved and removed. The portion forms a raised portion E1. As shown by a broken line in FIG. 4, the height (swell amount) t1 of the swelled portion E1 is higher than the height t2 of the swelled portion E2 when the colored layer is formed without performing defocus exposure on the projection lens 4b. Therefore, the accuracy (performance) of the color filter is not hindered and practically acceptable.

After the formation of the red R colored layer is completed, the substrate stage 3 is moved by one pitch of the colored layer in the X-axis direction x, and sequentially the openings BMb of the black matrix BM in the same manner as described above. The green G and blue B colorants applied above are repeatedly exposed and developed, and the red R, green G, and blue B colored layers are formed on the transparent substrate W in the black matrix BM. Formed vertically and horizontally aligned.
In the defocused state of the exposure light, the distance between the projection lens 4b and the transparent substrate W is set to be larger than the focal length of the projection lens 4b. It may be formed by setting the defocus amount f by making it smaller than the focal length by the predetermined value, and the same effect can be obtained by any exposure.

Example Next, a method for manufacturing a color filter according to an embodiment of the present invention will be specifically described.
(1) First, a black matrix resin made of a negative photoresist (BK4617 made by Tokyo Applied Chemical) is applied to the entire surface of the transparent substrate W with a spinner, and then the exposure amount is set to 200 mJ / cm ² through a photomask. Exposure light was irradiated at a wavelength of 365 nm. Then, as a development process, a transparent substrate irradiated with exposure light in a 1% aqueous solution of sodium hydroxide (KOH) is immersed for 70 seconds, and then baked at a temperature of 200 ° C. for 20 minutes to obtain a rectangular opening. A black matrix BM made of a lattice-shaped light shielding layer BMa with BMb arranged vertically and horizontally was formed on the transparent substrate W.

  (2) Next, after applying a red R coloring resin layer (colored layer) made of a negative photoresist (M302R manufactured by Sumitomo Chemical Co., Ltd.) on the entire surface of the transparent substrate W on which the black matrix BM has been formed, The projection exposure apparatus 1 is used to change the defocus amount of the projection lens 4b in various ways, and the projection resin 4b irradiates the coloring resin layer with exposure light passing through the opening 7a of the photomask 7. . Then, as a development process, a transparent substrate irradiated with exposure light in a 1.0% aqueous solution of sodium hydroxide is immersed for 70 seconds, and then baked at a temperature of 200 ° C. for 20 minutes to form a rectangular red R color. A layer was formed in the opening BMb of the black matrix BM.

  (3) Next, using the green G and blue B color resin layers made of negative photoresist (M302G manufactured by Sumitomo Chemical) and negative photoresist (M302B manufactured by Sumitomo Chemical), the treatment of (2) above is performed. Repeatedly, green G and blue B colored layers were formed in the openings BMa of the black matrix BM to manufacture the color filter CF. Then, a transparent electrode was deposited on the color filter CF.

(4) Further, the result of measuring the swelled portion E1 formed on the light-shielding layer BMa of the grid-like black matrix BM of the obtained color filter CF using a stylus type film thickness meter is obtained as a defocus amount f and swell Table 1 and FIG. 5 show the relationship of the height (swelling amount) t of the portion.
According to this, when the defocus amount f of the projection lens 4b is set in the range of 350 to 700 μm, a good exposure result in which the rising amount t1 is 0.5 μm or less is obtained, and the transparent formed on the transparent substrate W is obtained. It has been found that a high-precision color filter can be produced without causing an electrode peeling phenomenon. When the defocus amount f is larger than 700 μm, the straightness of the pattern of the opening 7a in the photomask 7 is deteriorated, the color layer and the color layer overlap on the black matrix BM, and the color filter CF becomes defective. .

  As described above, the color filter manufacturing method according to the embodiment applies the red R, green G, and blue B colored layers on the transparent substrate W on which the black matrix BM is formed, and then the projection exposure apparatus 1 is used. Manufacturing of a color filter for forming a filter colored in red R, green G, and blue B on the transparent substrate W by exposing each colored layer to the pattern of the opening 7a of the photomask 7 through the projection lens 4b. In the method, the projection exposure apparatus 1 includes a light uniformizing unit 4a in the exposure optical system 4, and the transparent substrate W is irradiated by the projection lens 4b with the exposure light that has passed through the light uniformizing unit 4a to each colored layer. In the exposure, the distance between the projection lens 4b and the surface of the transparent substrate W to be exposed is set to be shorter or longer than the focal length of the projection lens 4b.

  Therefore, according to the method for manufacturing a color filter according to the above-described embodiment, it is possible to expose a wide range of exposure areas A and A by a scanning method using a small photomask 7 and having no deflection thereof, and exposure optics. Since the exposure light whose light intensity distribution is made uniform can be projected on the entire surface of the photomask 7 by the light uniformizing means 4a of the system 4, the projection lens 4b passes through the opening 7a of the photomask 7 and the transparent substrate. The defocus amount f of the exposure light irradiated on W can be made uniform over the entire exposure areas A and A, and defocusing on the colored layer on the transparent substrate W corresponding to the opening 7a of the photomask 7 is achieved. The exposure distribution state can be appropriately formed.

Further, since the pattern of the opening 7a of the photomask 7 is transferred onto the transparent substrate W by the projection lens 4b, a transfer shift of the pattern of the photomask 7 due to the parallelism error of the light beam of exposure light occurs as in proximity exposure. There is no fear, and the pattern of the opening 7a of the photomask 7 can be transferred onto the transparent substrate W with high accuracy.
Therefore, it is possible to suppress the rising amount t1 in the overlapping portion E1 between the black matrix BM and the colored layer as much as possible, to improve the surface flatness of the color filter CF, and to improve the accuracy of the color filter CF.

Further, according to the color filter manufacturing method of the embodiment, the opening width h of the opening 7a of the photomask 7 is configured to be smaller than the opening width H of the opening BMb of the black matrix BM. Since the spread of light in the circumferential direction of the opening 7a of the photomask 7 can be increased, the light intensity distribution of the exposure light at the overlapping portion of the black matrix BM and the colored layer can be accurately reduced. Thus, the rising amount t1 of the rising portion E1 can be surely reduced.
Furthermore, since the distance from the projection lens 4b to the surface of the transparent substrate W to be exposed is shorter or longer than the focal length of the projection lens 4b, the defocus amount is set appropriately. The rising amount t1 at the rising portion E1 between the black matrix BM and the colored layer can be reliably controlled within the limit value, and the accuracy of the color filter CF can be further improved.

It is sectional drawing which shows an example of the projection exposure apparatus used when enforcing the manufacturing method of the color filter which concerns on one embodiment of this invention. It is a top view which similarly shows the relationship between the photomask and transparent substrate in a projection exposure apparatus. It is a top view of the color filter manufactured by the manufacturing method of the color filter which concerns on one embodiment of this invention. FIG. 4 is a cross-sectional view taken along the line II in FIG. 3. It is a diagram which shows the relationship between the amount of defocusing, and the amount of swelling of the colored layer on a black matrix.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projection exposure apparatus 3 Substrate stage 4 Exposure optical system 4a Light uniformizing means 4b Projection lens 5 Exposure part 6 Mask stage 7 Photomask 7a, BMb Aperture 8 Light source A Exposure area BM Black matrix BMa Shading layer CF Color filter L Optical axis W Transparent substrate (substrate)
f Defocus amount t1 Swell amount

Claims (3)

Manufacture of a color filter that forms a colored filter on a substrate by applying a colored layer on a substrate on which a black matrix is formed and then exposing the colored layer to a pattern of a photomask through a projection lens using a projection exposure apparatus. In the method
The projection exposure apparatus includes a light uniformizing unit in an exposure optical system, and the projection lens exposes the colored layer by exposing the substrate with exposure light passing through the light uniforming unit and exposing the colored layer. A method for producing a color filter, wherein exposure is performed at a distance shorter or longer than a focal length of a projection lens.   2. The method of manufacturing a color filter according to claim 1, wherein the opening width of the photomask pattern is smaller than the opening width of the black matrix. 3. The method of manufacturing a color filter according to claim 1, wherein a distance between the projection lens and the surface of the substrate to be exposed is shorter or longer than a focal length of the projection lens is 350 to 700 [mu] m.

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