JP3122498B2 - Manufacturing method of color filter - Google Patents

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 used for forming a color display device in combination with a liquid crystal, for example, a super twisted nematic liquid crystal.

[0002]

2. Description of the Related Art One side of a substrate constituting a liquid crystal cell has
A color display device in which a color filter having pixels of predetermined colors, for example, pixels of three colors of red, green and blue is formed and a liquid crystal layer is sandwiched between two opposing substrates is disclosed in, for example,
It is known from Japanese Patent No. 3122 and the like. In such a color filter, a smoothing film is provided for protecting pixels and smoothing a pixel forming portion. Generally, a polymer resin such as an acrylic resin, a polyimide resin, or an epoxy resin is used for the smoothing film. However, when a smoothing film is formed on the entire surface of the substrate, and a photolithography technique using a photosensitive resin or the like is used. In some cases, a smoothing film is formed by patterning that covers only the display section.

[0003] In the latter case of patterning that covers only the display portion, the edge portion of the smoothing film tends to have a sharp cross-sectional shape due to the turn-up caused by the penetration of the developer during development. FIG. 3 illustrates this state, where 1 is a substrate,
Reference numeral 2 denotes a pixel, reference numeral 3 denotes a smoothing film, and reference numeral 3a denotes an edge portion having an upwardly raised portion. The transparent conductive film 4 is formed on the upper surface of the smoothing film 3 in a later step. However, the sharp edge portion 3a tends to apply an excessive force to the portion 4a covering the edge portion 3a, and the step coverage is poor. In this case, the falling portion along the end surface of the smoothing film 3 becomes thin. For this reason, the wire is easily broken at the portion 4a, and the reliability is reduced.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention has been made to provide a color filter in which the transparent conductive film is not broken at the edge of the smoothing film.

[0005]

According to the present invention, a pixel of a predetermined color is formed on a substrate.
A photosensitive resin for forming a smoothing film is applied thereon, and then (a) a photomask in which a light-shielding film of a predetermined pattern is formed on one surface of a transparent mask substrate, and the other surface faces the substrate. To arrange. (B) UV light is irradiated from the side of the photomask on which the light-shielding film is formed, and the amount of light exposure of a portion of the photosensitive resin corresponding to the light-shielding film edge by utilizing the spread of the ultraviolet light at the light-shielding film edge. Exposing the photosensitive resin in a state where changes gradually. (C) developing the photosensitive resin on the mask substrate; By sequentially performing the above steps, a smoothing film having a cross-sectional shape such that the film thickness gradually decreases at the edge portion is formed.

[0006]

Since the thickness of the edge portion of the smoothing film is gradually reduced, the transparent conductive film formed on the upper surface of the smoothing film does not have a sharp shape as shown in FIG. As a result, disconnection is less likely to occur.

[0007]

Next, an embodiment shown in the drawings will be described. FIG. 2 is a process explanatory view of a manufacturing method according to one embodiment of the present invention, and FIG. 1 is a sectional view of a color filter manufactured by the method. In FIG. 1, reference numeral 1 denotes a substrate, 2 denotes a pixel, and 3 denotes a smoothing film, as in FIG. 3, but the edge 3 b of the smoothing film 3 has a cross-sectional shape like the edge 3 a in FIG. 3. It is not a sharp shape but a shape in which the film thickness gradually decreases with a gradient. For this reason, when the transparent conductive film 4 is formed on the upper surface of the smoothing film 3, the portion 4 b covering the edge portion 3 b is also gentle, and no excessive force is applied to this portion, and sharp edges are not formed. Since it does not have a downward shape, it also has an advantageous effect with respect to step coverage, so that the portion 4b can be easily formed with a predetermined thickness. The inclination of the edge 3b is 45 °.
It is desirable to make the following.

In FIG. 2, reference numeral 14 denotes a photomask,
A light-shielding film 12 is formed on one surface of a transparent mask substrate 11 in a predetermined pattern. The light-shielding film 12 is formed by, for example, forming chromium. In the exposure process, as shown in FIG. 2A, a substrate 1 on which pixels (not shown) are formed and a photosensitive resin 5 for forming a smoothing film is applied thereon.
Then, the above photomask 14 is overlaid and irradiated with ultraviolet light,
This is performed by exposing a portion other than the portion covered with the light-shielding film 12, but the photomask 14 is arranged in such a direction that the side on which the light-shielding film 12 is not formed faces the substrate 1,
Ultraviolet rays are irradiated from the side where the light shielding film 12 is formed.

In the photolithography technique, the distance between the mask and the object to be exposed, that is, the proximity amount is usually set to 100 μm or less in order to improve the transfer accuracy. Since the photomask 14 is arranged with the non-formed side facing the substrate 1, the proximity amount becomes larger than usual, and the influence of the spread of the ultraviolet light generated at the edge of the light shielding film 12 due to the diffraction phenomenon of the ultraviolet light is increased. . For this reason, the exposure amount of the portion corresponding to the edge of the light-shielding film 12 gradually changes with a gradient, but the ultraviolet rays pass through the mask substrate 11 after passing through the light-shielding film 12 and are slightly scattered. Therefore, the change in the exposure amount becomes gentler. In addition,
The spread of the ultraviolet light is caused by the substrate 1 and the photomask 1 at the time of exposure.
4 also changes with the distance.

Next, the substrate 1 is developed and the photosensitive resin 5
The exposed portion is removed and the remaining portion is used as the smoothing film 3. The edge portion 3 corresponding to the edge of the light shielding film 12 is removed.
As for b, the amount of exposure gradually changes, so that the amount removed during development also changes gradually, resulting in a shape whose film thickness gradually decreases. Thereafter, a color filter is completed through a transparent conductive film formation and other predetermined processes.

In the above embodiment, a positive type photosensitive resin is used as a material for forming the smoothing film. However, when the material is a negative type, only the position of the light shielding film is reversed. Through the process, a smoothing film having a shape in which the thickness of the edge portion gradually decreases with a gradient can be obtained.

[0012]

As is apparent from the above description, the method for manufacturing a color filter of the present invention positively utilizes the spread of ultraviolet rays at the edge of a light-shielding film during exposure processing using a photomask. Thus, the exposure amount at the edge portion of the smoothing film is gradually changed, and the edge portion of the smoothing film is formed in a cross-sectional shape whose thickness gradually decreases.

Therefore, the edge portion of the smoothing film does not have a sharp shape, and scattering is particularly promoted when ultraviolet light passes through the mask substrate, so that the edge portion becomes more gentle.
The transparent conductive film is also formed along the gentle shape of the smoothing film, and the step coverage at the time of forming the transparent conductive film becomes good, and it becomes easy to secure a predetermined film thickness at the edge portion, Disconnection of the transparent conductive film hardly occurs, and a highly reliable color filter can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a color filter according to a manufacturing method of the present invention.

FIG. 2 is a process explanatory view of one embodiment of a method for manufacturing a color filter of the present invention.

FIG. 3 is a cross-sectional view of a color filter according to a conventional manufacturing method.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 pixel 3 smoothing film 3b edge 4 transparent conductive film 5 photosensitive resin 11 mask substrate 12 light shielding film 14 photomask

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-115584 (JP, A) JP-A-2-193184 (JP, A) JP-A-62-163017 (JP, A) JP-A-4- 278902 (JP, A) JP-A-4-51204 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 5/20-5/28

Claims (1)

(57) [Claims] 1. A pixel of a predetermined color is formed on a substrate, a photosensitive resin for forming a smoothing film is applied thereon, and then the following steps (a), (b) and (c) are sequentially performed. Forming a smoothing film having a sectional shape such that the film thickness gradually decreases at the edge portion. (A) a step of arranging a photomask in which a light-shielding film of a predetermined pattern is formed on one surface of a transparent mask substrate so that the other surface faces the substrate; (B) UV light is irradiated from the side of the photomask on which the light-shielding film is formed, and the amount of light exposure of a portion of the photosensitive resin corresponding to the light-shielding film edge by utilizing the spread of the ultraviolet light at the light-shielding film edge. Exposing the photosensitive resin in a state where changes gradually. (C) developing the photosensitive resin on the mask substrate;