JPH02106755A - Pattern forming method - Google Patents

Abstract

PURPOSE:To easily obtain a stable pattern which has a prescribed film thickness and no fault by applying a colored photoresist on a substrate with a film thickness which is fully exposed till a light reaches the rear surface of the photoresist to form a pattern 7, and then applying the color photoresist on the pattern 7 with the same film thickness to that of the pattern 7, and subsequently exposing and developing, and by repeating the step as mentioned above to obtain the pattern with a thick film thickness. CONSTITUTION:The colored photoresist 5 is applied on the substrate with the film thickness which is exposed till exposure energy fully reaches to the rear surface of the photoresist with an usual exposure to form the pattern 7. The colored photoresist 5 is applied on the pattern 7 with the same film thickness to that mentioned above, exposed and then developed. Then by repeating the step of forming a thick pattern at a several times, the pattern with a prescribed film thickness is formed. Accordingly, the film thickness of the colored resist 5 is thin, and as the photoresist is fully exposed to the rear surface of the resist, even if the exposure of the colored resist 5 is set in a region in which an aberration between the pattern 7 and a mask 6 due to the light diffraction at the time of exposing the photoresist, is small, the side etching of the photoresist due to the shortage of the polymerization of the photoresist does not generate. Thus, the pattern which does not generate the chipping and the peeling of the resist is formed with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for forming patterns on colored resists used in the production of color filters and the like.

BACKGROUND TECHNOLOGY In general, the method of forming a pattern using a colored resist is the first method.
As shown in FIG.
The process consists of exposing the film to light through a process, removing unnecessary parts through development, and finally post-baking.

FIG. 2 shows the exposure characteristic curve of a negative colored resist.

The horizontal axis is the exposure amount, and the vertical axis is the remaining film rate.

As the exposure amount is changed, the remaining film rate changes from 0 to 1 at the exposure amount ET. That is, when the exposure amount is less than Ey, no film remains after development due to insufficient polymerization, and when the exposure amount is more than ET, polymerization is sufficiently performed and the film remains completely after development. In addition, colored photoresists contain light-absorbing factors such as pigments, so light absorption within the film is large, resulting in a light intensity distribution in the film thickness direction. This requires a very large amount of exposure.

For example, when 25% carbon is dispersed in a transparent resist, the transmittance is 1% or less at a film thickness of 1 μm (wavelengths 365-43
6 nm), and the film thickness is 1 as shown in Figure 2(b).
In the case of μm, an exposure amount of approximately 10000 J/cm is required.

Problems to be Solved by the Invention However, in the conventional method, if a predetermined film thickness is coated from the beginning and exposed, the exposure energy does not reach the lower part of the resist sufficiently, resulting in insufficient photoreaction at the lower part of the resist. In the case of negative resist, side etch 9 occurs,
Pattern chipping or peeling occurs. Furthermore, when attempting to fully expose the lower part, a very large amount of exposure is required, which increases the time required for exposure (and further increases the dimensional difference with the mask due to diffraction, etc.).

SUMMARY OF THE INVENTION In view of the problems of the prior art, it is an object of the present invention to provide a pattern forming method for easily manufacturing a color filter having a stable pattern without defects.

Means for Solving the Problems The present invention uses a colored photoresist in which pigments or dyes are mixed and dispersed on a substrate, and the film thickness is such that sufficient exposure energy reaches the bottom surface of the resist within the exposure dose range normally used. By repeating several times the steps of coating, exposing and developing to form a pattern, further coating the colored photoresist to the thickness described above on the pattern, exposing and developing to form an even thicker pattern. This makes it possible to form a pattern with a predetermined film thickness.

Function The technical means of the present invention has a thin film thickness, so even if the exposure amount is set in an area where the difference between the pattern and the mask due to diffraction etc. is small during exposure, the lower surface is sufficiently exposed. Because of this, side etch due to insufficient polymerization does not occur. Therefore, a pattern without chipping or peeling can be formed with high precision.

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

In FIG. 1(a), a colored photoresist 5 in which pigments, carbon, etc. are dispersed is applied to a substrate 4, dried, and then emitted from a high-pressure mercury lamp through a mask 6 on which a desired pattern is drawn. The photoresist is irradiated with collimated ultraviolet light with uniform exposure power by an optical system (not shown) to print the pattern of the mask onto the photoresist. Then, in another development process, the resist in the non-irradiated area is etched and peeled off, and then in the curing process, the remaining resist in the light irradiated area is thermally hardened to form a pattern 7 on the substrate. form. Furthermore, the colored photoresist 5 is applied over the pattern 7, and the series of steps described above are performed. At this time, the film thickness of the colored resist layer in one process is set to be thinner than a predetermined film thickness so as to ensure sufficient exposure amount ET at the lower part of the resist in the normal exposure range (400 mJ/cm2 or less). There is. A pattern 8 having a predetermined thickness is formed by repeating this series of steps once or multiple times.

For example, when using a negative colored resist with 25% carbon dispersed in Eva, as shown in Figure 2 (a), the resist film thickness is set to 0.5 μm in one step, and the prescribed thickness is achieved in two steps. A pattern with a film thickness of 1 μm is formed. At this time, the amount of exposure per time is about 150 (mJ/cm2), and this amount of exposure is a sufficiently practical exposure range.

Other materials for the colored photoresist include, for example, a pigment-filled resist made by Fuji Hunt Electronics Technology Co., Ltd., which is made of an acrylic photosensitive resin, that is, a blue resist (trade name: Color Mosaic R1, abbreviated as CR);
Green resist (trade name Color Mosaic G1, abbreviation CG), red resist (trade name Color Mosaic R1, abbreviation CR), black resist (trade name Color Mosaic 1)
The abbreviation CK) was used. A 1% by weight aqueous sodium carbonate solution was used as the developer.

In addition, although this example describes a colored resist agent, when a light-absorbing functional material is mixed into the photoresist instead of a pigment or coloring agent, a pattern can be formed in the same way with high precision. A stable pattern can be obtained.

As described in detail, the present invention enables stable patterning of a photoresist that absorbs a lot of light with high precision and without side etching, chipping, or peeling.

[Brief explanation of the drawing]

FIG. 1 is a pattern formation process diagram showing a comparison between an embodiment of the present invention and a conventional example, and FIG. 2 is a characteristic diagram of a colored photoresist. 1, 4...Substrate, 2, Strike, 3.6...Mask,

Claims (3)

[Claims] (1) Mixing coloring agents such as pigments or dyes on the substrate,
A dispersed colored photoresist is applied to a film thickness that allows sufficient exposure energy to reach the bottom surface of the resist within the range of exposure that is normally used, and is exposed and developed to form a pattern.
Furthermore, a pattern having a predetermined thickness is formed by repeating several times the steps of applying the colored photoresist to the thickness above the pattern, exposing it to light, developing it, and forming an even thicker pattern. Pattern formation method (2) The colored resist material is a colored material containing a pigment and a photosensitive resin whose composition is a photopolymerization initiator containing a polyfunctional acrylate monomer, an organic polymer binder, and a trihalomethyl-s-triazine compound. The pattern forming method according to claim 1, characterized in that (3) The exposure amount E is set to several hundred mJ or less, and the exposure energy on the lower surface of the colored resist coated on the substrate is E_
Claim 1 characterized in that the film thickness range is T (exposure amount at which the remaining film rate of the colored resist is from 0 to 1) or more.
The pattern formation method described.