JPH02192728A - Formation of pattern - Google Patents

Abstract

PURPOSE:To form patterns having a resolving-property nearly identical with that of opening patterns by a method wherein the opening patterns are formed in a P-type resist film and after a thin film consisting of a desired material is formed to perform an entire surface etching, the resist film is peeled. CONSTITUTION:Opening patterns 9 are formed in a P-type resist film 8 on a substrate 1, a gelatine film 2 is formed and an entire surface etching is performed until the surface of the film 8 is exposed. Then, an entire surface exposure is performed to develop and the film 8 is peeled to pattern gelatine patterns 2'. Then, the patterns 2' are dyed into a desired color to form first- color color filter patterns 3 and after an intermediate film 4 is formed, second- color color filter patterns 5 and third-color color filter patterns 6 are respectively formed and a protective film 7 is formed. Thereby, patterns, which have a resolution nearly identical with that of the patterns 9 in the film 8 and consist of a desired material, can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a pattern forming method used for forming, for example, color filters and semiconductor devices.

[Conventional technology]

FIGS. 10(a) to 10(C) are cross-sectional views illustrating an example of a conventional pattern forming method applied to a color filter forming method formed by, for example, a dyeing method.

In the figure, first, as shown in the figure (,), a filter base material made of photosensitive gelatin or casein with ammonium gold dichromate added thereto is first coated on a substrate 1 made of, for example, a silicon or glass plate. A gelatin film 2 having a desired thickness is formed by coating by a method.

Next, using photophosphorography technology, this gelatin film 2 is
After patterning, the pattern is dyed in a desired color, for example red, to form a first color filter pattern 3. Next, as shown in FIG. 5(e), the first color filter pattern 3 was formed. After coating the transparent polymer resin on the substrate 1 by spin coating to form the intermediate film 4, Repeat the same process several times, dye it green for example, and make a second
A color filter pattern 5 of a different color and a color filter pattern 6 of a third color are formed by dyeing, for example, a back color, and finally, a transparent polymer resin is applied by a spin coating method, and a protective film 7t is formed to complete the process. was.

[Problem to be solved by the invention]

However, in the conventional color filter forming method, the gelatin film 2 has good transparency after buttering;
It was necessary to have excellent dyeing properties, and for this purpose it was necessary to use even those with poor pattern resolution. In addition, when the filter base material is formed from gelatin with ammonium dichromate, etc., the gelation point is around room temperature, so it is kept warm during use.
The thickness of the gelatin film 2 sometimes varied. Furthermore, since the color filter patterns 3, 5, and 6t are formed by photolithography using a negative resist, the pattern shape has a large tapered portion. Therefore, in the conventional method of forming color filters, the filter base material must have good dyeability and transparency, so there are restrictions on the materials, and there are problems such as inferior resolution compared to general photoresists. .

Therefore, this invention was made in order to improve the above-mentioned conventional problems, and it is possible to use a film made of a material that cannot provide the same resolution as a positive resist due to dyeability, photosensitivity, resolution, etc. Formed on positive resist,
The object of the present invention is to provide a pattern forming method capable of forming a positive pattern having a resolution equivalent to that of a resist by etching the entire surface.

[Means to solve the problem]

In the pattern forming method according to the present invention, a positive resist film is formed on a substrate, an opening pattern of a desired size is formed in this positive resist film, and then a desired resist film is formed on the positive resist film having the opening pattern. forming a thin film of material;
After etching the entire surface until the thin film of the desired material formed on the positive resist film is removed, the positive resist film is completely peeled off to form a pattern of the desired material in the opening pattern.

[Effect]

In the present invention, a pattern of a desired material is formed having a resolution substantially equivalent to the size of the opening pattern of the positive resist film.

〔Example〕

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

Figures 1 (-) to (,) are cross-sectional views illustrating an embodiment in which the pattern forming method according to the present invention is applied to a color filter forming method, and the same parts as in the previous figures are denoted by the same reference numerals. I'll attach it. In the same figure, first, the same figure (&)
As shown in FIG.
800 (manufactured by Tokyo Ohka) by the spin coating method to form a positive resist film 8 with a thickness of about 1 μm on the entire surface, and then use photolithography technology to coat the area where you want to completely form the first color filter. The opening pattern 9 is formed only in a width of approximately 2 μm. Next, as shown in Φ) in the same figure, a filter base material made of gelatin with ammonium dichromate is coated on the positive resist film 8 on which the opening pattern 9 is formed, using a spin coating method to a thickness of about 3 to 4 μm. A gelatin film 2 is formed. At this time, it is advantageous for the thickness of the gelatin M2 to completely fill the opening pattern 9 to the same level as the thickness of the positive resist film 8 in order to fully control the thickness of the filter to be formed thereafter. Moreover, when this gelatin film 2 is thin,
Although the film thickness of the opening pattern 9 is thinner than the total film thickness obtained by adding the film thickness of the positive resist film 8 and the film thickness of the gelatin film 2 on this positive resist film 8, the film thickness can be increased. Accordingly, the film thickness flatness of the gelatin film 2 can be improved. Next, as shown in FIG. 2C, a mixed gas containing oxygen is applied to the surface of the gelatin film 2, and etching is performed on the entire surface until the surface of the positive resist film 8 is exposed. In this case, the etching time varies depending on the gas mixture ratio used, but is approximately 15 minutes to 5 hours. At this time, the positive resist film 8
By finishing the etching of the entire surface when the surface of the resist film 8 is exposed, the thickness of the gelatin film 2 can be made the same as that of the positive resist film 8, and the film thickness can also be controlled thereby. Next, as shown in FIG. 3(d), the entire surface is exposed. As a result, the positive resist film 8 becomes soluble in the alkaline solution, and the gelatin film 2 becomes insoluble in water. Next, it is developed using NMDW (manufactured by Tokyo Ohka) as a developer,
The gelatin pattern 2' is covered only in the area where the positive resist film 8 is peeled off and the color filter is to be formed. Next, dye this gelatin pattern 2' with a desired color, for example, red, by adding R-136 (manufactured by Nippon Kayaku) to pure water.
? The solution was dissolved in a dye solution at a concentration of 1/1, immersed in an aqueous dye solution, and dyed at a temperature of about 80°C, a pH of 5.0, and a dyeing time of 10 minutes. A color filter pattern 3 is formed.

As a result, pattern formation special condition 2 of gelatin pattern 2'
．． The width, which was 0 μm, swelled by about 0.2 μm, and the width decreased to about 2.0 μm.
A first color force 2-filter pattern 3 of 2 μm is formed. Next, on the substrate 1 on which the first color filter pattern 3 is formed, FVR (manufactured by Fuji Pharmaceutical Co., Ltd.) is applied as a transparent polymer resin by a spin coating method to form the first intermediate film 4.
form. Next, on this first interlayer film 4, similarly to the color filter pattern 3 for the first color, a pattern with a width of about 2, A gelatin pattern with a second color of 0 μm is formed. Next, as a green dye, CVall (
Nippon Kayaku) in pure water? The color filter pattern 5 of the second color is formed by immersing it in an aqueous dye solution dissolved at a concentration of /l and dyeing it under the same conditions as above. In this case as well, like the color filter pattern 3 of the first color, the color filter pattern 5 of the second color also expanded in pattern width due to swelling, and became about 2.2 μm. Next, on the first intermediate film 4 on which the color filter pattern 5 of the second color is formed, the above-described transparent polymer resin is applied by the FVR'i spin coating method to form the second intermediate film 4. Furthermore, this second
Similarly to the color filter pattern 3 for the first color, a region approximately 019μ steps away from the edge of the color filter pattern 5 for the second color has a width of approximately 2.0 μm on the middle M4.
Form a gelatin pattern with the third color. Next, as a blue dye, B43P (manufactured by Nippon Kayaku) was added to pure water at 17%
It is immersed in an aqueous dye solution dissolved at a concentration of 1,000 ml, and dyed under the same conditions as described above to form a third color color filter butter 76. In this case as well, the third color filter butter 76 is applied to the first color filter pattern 3 and the second color filter butter 76.
Similar to the colored color filter pattern 5, the pattern width becomes approximately 2.2 μm due to swelling. Finally, the second intermediate $4 where this third color color filter pattern 6 is formed.
The above-mentioned transparent polymer resin (FVR) is coated by the full spin coating method to completely form the surface protective film γ.

According to such a method of forming a color filter, the first color color filter pattern 3. The width of each filter pattern of the second color filter pattern 5 and the third color filter pattern 6 is approximately 2.2 μm, and the dimension between each filter pattern is approximately 0.8 μm, and a taper occurs at the pattern periphery. No minute force, 7-filter could be formed. That is, in the conventional forming method, the line and space filter butter/width is 3 to 4
μm is the limit, and it is not possible to form a filter pattern with a width of about 2.0 μm.Also, even if the entire filter pattern with a width of about 5 μm is formed, there will be a Chi-Ha portion of about 1 to 2 μm in the periphery, so the filter pattern When the distance between the patterns was about 1 μm, the patterns overlapped and could not be formed, but according to the forming method of this embodiment, the fine three-color color filter patterns 3, 5, 82>! It can be formed with X precision, and the second
Three color spectral characteristics of red (R), green (G), and blue (B) as shown in the figure were obtained. Further, according to such a method of forming a color filter, as shown in FIG. 3, three color filter patterns 3,5. A color filter can be formed with an anti-dye wall 10 formed therebetween. Further, as shown in FIG. 4, a white filter pattern 11 is formed between the first color filter pattern 3 and the second color filter pattern 5 to form nine color filters. Furthermore, the color filter formed in this manner can be combined with a color solid-state image sensor in which a large number of light-receiving parts are made of dodecyl gold in the semiconductor substrate 1', as shown in FIG. A high-resolution color solid-state imaging device can be obtained. For example, the separation width between the transfer section and pixels of a color solid-state image sensor is approximately 1
In the case of .mu.m, when the pixel part is 2 .mu.m x 2 .mu.m, a 1-inch format can theoretically accommodate 4 million pixels. Furthermore, as shown in FIG. 6, by using it in an auto white balance sensor and a liquid crystal display, products with good uniformity and high yield can be obtained.

FIGS. 7(a) to (d) are cross-sectional views illustrating another embodiment in which the pattern forming method according to the present invention is similarly applied to a color filter forming method. The same reference numerals are given. In this embodiment, primary color filters of red (R), green (G), and blue (B) are formed on a substrate using a colored polymer solution in which a polymer and dye are dissolved as a filter base material. Here, polyglycidyl methacrylate (PGMA) was used as the polymer, and ZaponFast Fiery Red B was used as the red dye.
(manufactured by BASF), N1honthrena B as green dye
r eye 1iant Green FFB (manufactured by Sumitomo Chemical),
Mikethren Br1lliant B for blue dye
Use lueR8M (manufactured by Mitsui Toatsu). A mixed solution of ethyl cellosolve and dimethylacetamide (DMAC) is used as a solvent. Using the above materials, colored polymer solutions in which 5 to 20 parts of dye is dissolved in PGMA are prepared in three colors: full red, green, and blue.

In the figure, first, as shown in (-) in the figure, a positive type photoresist (OFPR800) is coated on the surface of the substrate 1 by a spin coating method, and a positive type photoresist film with a thickness of about 1 μm is coated on the entire surface. After forming a'ft, an opening pattern 9t is formed only in a region (width about 2 μm) where the first color filter is desired to be formed using a photolithography technique.

Next, on the positive resist film 8 on which the opening pattern 9 was formed, a red colored polymer solution as a filter base material was applied by a spin coating method to form a red colored polymer film with a thickness of 4 to 5 μm. 10 using oxygen as etching gas
Etching is carried out for a minute to two hours to form a color filter pattern 3 of the first color (red) as shown in FIG. 3(b). Next, an opening pattern l is formed in which a part of the p-positive resist film 8 is cut out as a pattern by an exposure method in the formation region of the second color color filter approximately 1 μm away from the edge of the first color color filter pattern 3. do. Next, in the same manner as in the formation of the first color color filter pattern 3, a green colored polymer solution was applied by the spin coating method, and then 10% was applied with oxygen in the same manner.
Etching is carried out for a minute to two hours to form a second color (green) color filter pattern 5 as shown in FIG. Furthermore, after forming an opening pattern 9 in which a part of the positive resist film 8 is cut out as a pattern by an exposure method in the formation region of the third color color filter approximately 1 μm away from the edge of the second color color filter pattern 5, Similarly to the second color filter pattern 5, a blue colored polymer solution is applied and etching is performed to form a third color (blue) color filter pattern 6t as shown in FIG. Next, the entire surface of the substrate 1 on which the three-color color filter patterns 3, 5° 6 have been formed is exposed, developed, and the remaining positive resist film 8 is peeled off.
The surface protective film 1 is formed by applying R by a spin coating method to complete the process. This makes it possible to form a fine, well-shaped color filter with no uneven coating.

As still another embodiment of the pattern forming force method according to the present invention, a case where it is applied to a method of forming a color filter will be described. In this embodiment, a color filter is formed on a color detection device substrate on which a light receiving section is formed using a filter base material in which pigment is dispersed in a polyimide precursor. Here, PSI-G (manufactured by Chisso) is used as the polyimide precursor, and Chromophtal 5carlet is used as the red pigment.
RN (manufactured by Ciba Geigy), IRGALIT in green pigment
E 6G (manufactured by Ciba Geigy), Cromofi for blue pigment
ne Blue 5R5020 (Dainichiseika M) is used, and N-methylpyrrolidone (NMP) is used as a solvent.

First, as mentioned above, make a positive mold on the surface of the substrate 1).
(OF'PR800) film thickness is approximately 1μ by spin coating method.
After forming a process-grade positive resist film, an opening pattern is formed in which the region (approximately 1 m) where the first color color filter is to be formed is a punched pattern. After coating the body to a thickness of about 10 μm using a roll coater, a developer (NM
DW)'i Wet etching is performed over time using a diluted developer solution diluted approximately 4 times. In this case, the etching time was approximately 40 minutes until the entire surface of the positive resist film was exposed.

Next, the polyimide precursor (PSI-G) is partially crosslinked by heating at about 120°C for 16 minutes using a hot plate (hot plate), and the entire surface is exposed to light.
The positive resist film is peeled off using k.

After that, use the hot plate again for 200-300'
C, heating for 15 minutes to form a polyimide precursor (PS
I-G)'i completely crosslinked to form a first color color filter that is insoluble in alkaline solutions. Subsequently, the polyimide precursor in which the green pigment and blue pigment were completely dispersed was subjected to the same treatment as described above to form a second color filter and a third color filter, respectively.

According to the forming force method of such a color filter, the diameter is 4
As shown in FIG. 8, color filters with good film thickness uniformity can be obtained for inch wafers. In other words, in the past, when a precursor solution containing a pigment was directly applied by spin coating, the center part became thicker due to the thixotropic phenomenon as shown in Figure 9, but with the forming method according to this embodiment, A color filter with high film uniformity over the entire surface of the wafer can be obtained.

As another embodiment of the pattern forming method according to the present invention, a case where it is applied to a method of forming a color filter for a liquid crystal display will be described. In this embodiment, a colored polymer in which a dye is dissolved in the polymer is used as the filter base material. Here, the aforementioned polyglycidyl methacrylate (PGMA) was used as the polymer, and Zapon Fas was used as the red dye.
t Fiery Red B (manufactured by BASF), green dye with N1hon throne Br1lli-ant G
reen FFB (manufactured by Sumitomo Chemical), Mik- in blue dye
ethren Br1lliant Blus R8N
(manufactured by Mitsui Toatsu), and a mixed solution of methylene chloride and dimethylacetamide (DMAC) is used as the solvent.

Using the above materials, colored polymer solutions of three colors, red, green, and blue, are prepared by dissolving each dye in the PGMA. First, as explained in the embodiment of FIG.
Apply a positive resist (OFPR800) to the 0 surface using the spin coating method, and apply the three colors of red, green, and blue using the same method.
Form a color filter of color. In this case, the pattern width is different from the example shown in FIG. 7, and is 100 μm x 200 μm.
That's about it. As a result, it is possible to form a three-color color filter without uneven coating.

According to such a method of forming a color filter, a color filter for a liquid crystal display that is free from uneven coating and has a uniform film thickness at room temperature can be obtained. In other words, in the past, color filters were formed by dyeing gelatin patterns, and since the gelation point of the gelatin photosensitive solution is around room temperature, it was necessary to heat it above room temperature to make it into a sol state. During spin coating, a temperature difference occurs between the coating and the substrate 1, which causes uneven coating. This uneven coating was particularly likely to occur with large patterns. According to this embodiment, since the process can be performed at room temperature, the above-mentioned problems can be completely solved.

In the above-mentioned embodiment, the entire surface of the gelatin film 2 was etched until the surface of the positive resist film 8 was exposed. Further etching may be performed as long as it can be controlled. In this case, it is desirable that the etching rate of the positive resist film 8 is approximately the same as that of the gelatin film 2, but the etching rate is particularly high and the pattern shape of the gelatin film 2 may be affected. For example, any method may be used as long as it does not cause major damage such as pattern peeling.

In addition, in the above-mentioned embodiment, flatness is provided by increasing the thickness of the gelatin film 2, but the same effect can be obtained with a thin film by lowering the viscosity of the gelatin film 2. 4!This does not apply when flatness is not required for P).

Further, in the above embodiments, exposure and development was used to peel off the positive resist film, but it may also be peeled off using an appropriate organic solvent.

Further, in the above embodiment, the gelatin film 2 is applied by a spin coating method, but any material and film that can fill the opening pattern 9 and maintain the necessary flatness of the gelatin film 2 can be used. Any formation method may be used.

In addition, in the above-mentioned example below, the color scheme of the color filter is three colors of red, green, and blue, but it is a primary color system.

Any complementary color may be used and the same effect can be obtained.

Further, in the above-mentioned embodiment, a mosaic color filter is formed, but a stripe-like color filter may also be used, and the same effect as described above can be obtained.

In addition, in the above-mentioned embodiment, a dyed color filter was explained, but it is also possible to use a coloring material that uses a mixture of pigments or dyes, such as a coloring material that uses a pigment and a polyimide precursor or an acrylic polymer, and a dye and a polyimide precursor. A colored material made of acrylic resin or acrylic polymer may also be used, and the same effect as described above can be obtained.

In addition, in the above-mentioned embodiments, the method for forming the force 2 filter was explained, but even if there is another purpose, materials, pattern shapes, and solutions that cannot obtain resolution almost equivalent to that of positive resists may be used. A material that requires a complicated process to improve image quality may be used, and the same effect as described above can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, after forming a positive resist gt on a substrate and forming an opening pattern of a desired size on this positive resist film, the positive resist film having the opening pattern is A thin film of the desired material is formed on the positive resist film, the entire surface is etched until the thin film of the desired material formed on the positive resist film is removed, and then this positive resist film is peeled off to form a pattern of the desired material. As a result, a pattern of the desired material having a resolution approximately equal to the size of the opening pattern of the positive resist film can be obtained. Further, since the film is formed by etching the entire pattern of the desired material, by optimizing the etching gas composition etc., the pattern film thickness of the desired material can be formed uniformly. Furthermore, since the shape of the desired material pattern depends on the opening pattern formed in the positive resist film, extremely excellent effects such as the ability to improve the shape of tapered portions etc. can be obtained.

[Brief explanation of the drawing]

FIGS. 1(&) to (e) are cross-sectional views of steps for explaining an example in which an embodiment of the pattern forming method according to the present invention is applied to a color filter forming method, and FIG. 2 shows the spectral characteristics of the color filter. 3 and 4 are cross-sectional views showing other configurations of the color filter according to the present invention, and FIG. 5 is a cross-sectional view showing an example in which the color filter according to the present invention can be applied as a color filter of a color solid-state imaging device. 6 is a sectional view showing an example in which the color filter according to the present invention can be applied as a color filter of an auto white balance sensor, and FIGS. 7(a) to (d) are other embodiments of the pattern forming method according to the present invention. For example, FIG. 8 is a cross-sectional view of a process for explaining another example applied to the method for forming a filter, FIG. 8 is a diagram showing the film thickness distribution of a color filter according to the present invention, and FIG.
Figure 10 shows the film thickness distribution of a conventional color filter.
Figures (a) to (C) are cross-sectional views illustrating a conventional method for forming a color filter. 1・φ・・Substrate, 1′・−・Semiconductor substrate, 2・−・・
Gelatin film, 2'... Gelatin pattern, 3...
- Color filter pattern for the first color, 4... Intermediate film, 5... Color filter pattern for the second color, 6
1111...Third color filter pattern, T...
... Preservation ag, a... Positive resist film, 9...
・Aperture pattern, 10. Anti-dye wall, 11. White filter pattern, 12. Light receiving part.

Claims (1)

[Claims] After forming a positive resist film on a substrate and forming an opening pattern of a desired size in this positive resist film, a thin film of a desired material is formed on the positive resist film having the opening pattern, and A pattern forming method characterized by etching the entire surface until a thin film of a desired material formed on a type resist film is removed, and then peeling off the positive type resist film.