JPS6058442B2 - Color filter manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing a color filter for a solid-state image sensor.

[Background of the Invention] Conventionally, color filters for solid-state image sensors include:
For example, as shown in Japanese Patent Publication No. 52-17375, it is provided on a flat substrate such as a glass substrate, and is written on a solid-state image sensor (also known as a substrate), or some of the inventors' There are devices that are directly provided on solid-state image pickup devices, such as the one previously filed as Japanese Patent Application No. 54-21855.

In manufacturing any of these, a coating film of a photosensitive material is first formed, exposed through a mask with a predetermined pattern, developed, and dyed to form a first color filter film. If a second color filter film is formed immediately on top of the first color filter film, the first color filter film will also be further dyed when the second color is dyed.
A transparent protective film is provided on the colored filter film, and a second colored filter film is formed thereon. Furthermore, the next protective film is provided on top of this, and a third color filter film is formed on top of this. In addition, when the color filter is provided directly on the solid-state image sensor, a protective layer is provided on the substrate for the purpose of flattening the substrate surface and protecting the substrate from contamination.
It is said that it is preferable to form a color filter film with a different color.

As the photosensitive material for the color filter film, it is preferable to use a water-soluble photosensitive material, such as a gelatin/dichromate-based material, since it is easy to dye.

The protective film is preferably hydrophobic, and therefore preferably made of a polymer compound soluble in an organic solvent.
Further, since it is necessary to make a hole in the bonding pad portion, it is more preferable to use a photosensitive material. When an aqueous solution of a photosensitive material is applied onto such a hydrophobic coating film, the wettability of the coating film surface is poor and uneven coating tends to occur, which has the disadvantage that it is difficult to form a good rough filter film.

[Object of the Invention] An object of the present invention is to provide a method for manufacturing a color filter having a uniform color filter film.

[Invention (already required)]

The method for producing a color filter of the present invention is characterized in that the surface of the protective film is subjected to plasma treatment, and a color filter film is provided thereon.

By forming a protective film on a substrate or a color filter film and subjecting it to plasma treatment, the coating properties of the film have been dramatically improved. As a plasma atmosphere, argon or the like is also suitable, but oxygen plasma is particularly good. Furthermore, conventionally, it has been considered preferable to use polyglycidyl methacrylate (hereinafter abbreviated as PGMA) as the protective film.

This is due to the fact that PGMA becomes a strong hydrophobic film when heated, and that it exhibits properties as a positive resist when exposed to deep ultraviolet light, making it easy to drill holes in the bonding pad area. . Also in the present invention, it is preferable to use PGMA. However, when a PGMA coating film is formed on an uneven substrate and subjected to exposure, development, rinsing, and drying, cracks may occur on the coating film surface. The rate of cracks occurring is particularly high in areas where the substrate has large irregularities. During staining, the solution seeps through this area and contaminates the filter membrane. This also applies to the protective film that has been subjected to the plasma treatment described above. It has been found that this problem can be solved by incorporating a small amount of water into the developer solution. 0.5% water (by volume)
By using the developer added above, the PGMA coating film becomes a good protective film without cracks. On the other hand, when a developer with a large amount of water is used, the residual film rate in unexposed areas decreases. In order to maintain the properties as a protective film, it is desirable that the residual film rate is as high as possible, and the residual film ratio is preferably 70% or more, more preferably 80% or more. Figure 1 shows methyl ethyl ketone (
PGMA coating film (180°C bake) using a developer containing 5 volumes of MEK and 2 volumes of ethanol with water added.
shows the remaining film rate. As is clear from the figure, the preferable amount of water added is 4% or less, and the more preferable amount is 3.5% or less. As a developer for PGMA, alcohol (ethanol, methanol, etc.) or alcohol and ketone (
MEKl (methyl isobutyl ketone, etc.) is used, and when water in the above range is added to this, it becomes an extremely excellent developer.

Therefore, a color filter having a protective film developed with such a developer exhibits excellent characteristics. [Examples of the Invention] The present invention will be explained below with reference to Examples.

Example 1 Polyglycidyl methacrylate was coated as a protective film on a solid-state image sensor to a thickness of 0.7 μm, and baked at 200° C. for 1 hour to form a strong hydrophobic film.

Thereafter, plasma treatment was performed for 3 minutes under the conditions of oxygen partial pressure of 2t0rr and high frequency power of 20W. Thereafter, when an aqueous gelatin solution was applied, a uniform and good film could be formed.
Note that the contact angle of water changed from 52 degrees to 17 degrees before and after the plasma treatment, indicating that the wettability of water was improved. FIG. 2 shows a cross section of a color filter provided with such a protective film. 1 is a solid-state image sensor; 2, 3, 4, and 5 are protective films; 6 is a first color filter film; 7 is a second color filter film; 8 is a third color filter film. It is.

Example 2 In the process of configuring a color filter on an M0S type solid-state image sensor, 0.7 μm (7) PGMA was applied between the color filter films in the same manner as in Example 1, and after baking at 200° C. for 1 hour, it was heated with a 3KWXe lamp. Far ultraviolet light was irradiated for 6 minutes.

After that, MEK5Occl ethanol 20CC1 water 1c
It was immersed in the developer solution of c for 2 minutes, further immersed in methyl isobutyl ketone for 2 minutes, and then dried. As a result, PGMA was completely removed in the exposed areas, and a strong protective film could be formed in the unexposed areas. [Effects of the Invention] As described above, according to the present invention, a uniform and good Rani filter can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the present invention, and FIG. 2 is a sectional view of a color filter according to an embodiment of the present invention. 1... Solid-state image sensor, 2, 3, 4, 5...
...Protective film, 6,7,8... Color filter film.

Claims (1)

[Claims] 1. A step of forming a protective film on a substrate or a color filter film, a step of subjecting the protective film to plasma treatment, and a coating film of a water-soluble photosensitive material on the plasma-treated protective film. A method for manufacturing a color filter, comprising the steps of forming a predetermined pattern, and dyeing the pattern. 2. The method of manufacturing a color filter according to claim 1, wherein polyglycidyl methacrylate is used as the protective film.