JPH01225902A - Method of stripping color filter - Google Patents

Abstract

PURPOSE:To eliminate the undesirable influence on a substrate and the attachments thereof by projecting UV rays on a color filter and processing the filter by using water alone or a liquid mixture composed of the water and org. solvent. CONSTITUTION:The far UV rays are projected on the color filter and the color filter is processed by using the water alone or the soln. prepd. by mixing the water and the org. solvent at a specified ratio. The colored layer of the color filter to be used is formed by dyeing synthetic resin photoresists of an acrylate system, etc., in addition to gelatin, low molecular weight gelatin casein, glue, etc., to be used as natural protein by dyes. The recovery of the substrate of, for example, a solid state image pickup element of high additive value which cannot heretofore be recovered is thereby enabled without flawing the photodetecting surface and the other attached parts.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for peeling off a color filter, and more particularly, to a method for removing a color filter without adversely affecting a substrate and its attached parts. .

[Problems with conventional technology]

Conventionally, the most well-known method for forming a color filter layer on a substrate such as a solid-state image sensor or a glass plate is the "staining method." When the substrate is a solid-state image sensor, this dyeing method coats the irregularities of the substrate with a resin that has excellent transparency, flatness, and adhesion, and then exposes and develops it to form the desired pattern. After flattening, a dyeable resist is coated, exposed and developed to pattern the desired dyeing area, and then the patterned area is dyed with a dye having predetermined spectral characteristics. The resin is coated with a resin having the following properties, exposed and developed to form a desired pattern and provide an intermediate layer.

After that, a color filter is formed by repeating the dyeing layer and the intermediate layer several times in that order.

However, the color filter layer formed on the substrate by applying this dyeing method has problems such as uneven resist coating, uneven development, etc.
Unevenness due to uneven dyeing or the like may occur over the entire layer, or scratches may occur on the layer due to adhesion of dust or the like when forming the color filter layer.

Furthermore, in recent years, high reliability has been required, and color filter layers are required to be formed with even greater accuracy, so the yield rate for manufacturing color solid-state image sensors is currently extremely low. Therefore, if the above-mentioned problems such as unevenness and scratches occur, it is necessary to
It is necessary to peel off the color filter layer from the substrate such as C[l].

Conventionally known methods for removing the film include an acid treatment method using concentrated sulfuric acid or the like, and a method of immersing the entire film in a basic aqueous solution such as sodium hydroxide or potassium hydroxide.

Although these treatment methods can easily peel off the color filter layer, they not only roughen the C00 surface but also dissolve the aluminum wiring on the CCO surface, making it difficult to reuse the CCD substrate after peeling. was not possible.

Also, JP-A-61-148402, JP-A-62-
Although peeling methods such as those disclosed in Japanese Patent No. 124174 are known, these methods have the problem that the color filter cannot be peeled off with sufficient reproducibility from the surface of the CCD substrate.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for removing color filters that eliminates the above-mentioned problems and does not adversely affect the substrate and its accessories.

(Means for Solving the Problems) The color filter of the present invention is irradiated with far ultraviolet rays with an exposure energy of 5 J/d or more, and then water alone or water and an organic solvent are added at a certain ratio, preferably 90% or less, preferably 30% It is characterized in that the treatment is performed using a solution mixed at % to 70% by weight.

The colored layer of the color filter used in the present invention is made of gelatin used as a natural protein, low molecular weight gelatin casein, grue, etc., as well as acrylate-based synthetic resin photoresist (for example, JP-A-58-205146). It is dyed.

-a, color separation filters rarely have only a colored layer formed on the substrate, and often include a smoothing layer, intermediate layer, overcoat layer, etc. in addition to the colored layer. When the substrate is a solid-state imaging device, the smoothing layer is a transparent layer provided to soften and flatten the uneven surface of the substrate, and is formed using, for example, a transparent negative resist that is difficult to stain. Specific examples of the negative resist include polystyrene, polyacrylic ester, polymethacrylic ester, polyimide, urethane, or polycarbonate negative resists.

In addition to the above-mentioned smoothing layer, the color filter may be an overcoat layer using the same photoresist as the above-mentioned smoothing layer, or an overcoat layer interposed between each dyeing layer with the above-mentioned overcoat layer as an intermediate layer. There may be a color filter with a multilayer structure.

Examples of far ultraviolet light sources used in the present invention include:
Low-pressure mercury lamps, high-pressure mercury lamps, xenon mercury lamps, etc. are known.

The exposure energy when irradiating this far ultraviolet light is 5J/
It is sufficient if it is more than CD.

In addition to ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone, the solvent used in the present invention may be any solvent as long as it dissolves in water. Among these, methyl ethyl ketone, cyclohexanone, toluene, methyl cellosolve, and tetrahydrofuran are preferably used.

In the treatment of the present invention, for example, a substrate having a color filter layer irradiated with deep ultraviolet rays at an exposure energy of 5 J/cd or more, preferably 20 J/cd, is treated with water alone or with water and the above organic solvent in a certain amount of 90% by weight or less. Preferably 341
% to 70% by weight of the mixed solvent or paper treatment. As the processing conditions, the processing temperature is 50
~200°C, more preferably 80~150°C,
The treatment time is usually 1 to 24 hours, preferably 5 to 9 hours.

[Example 1] (1) Preparation of color filter on solid-state imaging element Negative transparent photoresist 1-FVR (
Fuji Pharmaceutical Co., Ltd. (Product name) was applied to a film thickness of 1.0 μm, and then an i-line reduction projection exposure device (Ni
(manufactured by Kon) and developed. A smoothing layer was formed by repeating this operation several times. followed by 10% by weight
A gelatin aqueous solution containing ammonium dichromate was spin-coded onto a dyed photoresist to a film thickness of 1.5 μm, and a predetermined pattern was formed by exposing and developing using the above exposure device. Thereafter, it was immersed in a dyeing solution, washed with water, and dried to form a colored layer for color separation.

As the dye, any dye such as acid dye, reactive dye, basic dye etc. can be used, but specific examples include: l) Red dye, for example, Suminol Sealing Scarlet G (product manufactured by Sumitomo Chemical) 2) Green dyes include, for example, Suminol Sealing Brilliant Green 5G (trade name manufactured by Sumitomo Chemical) 3) Blue dyes include, for example, Kayanol Sealing Blue GW (trade name manufactured by Nippon Kayaku) name) etc. are known.

Furthermore, in order to protect the dyed layer, the same treatment as for the smoothing layer was performed and an overcoat layer was provided, thereby producing a substrate having a color filter.

(n) Peeling of color filter The solid-state imaging element having the color filter obtained above was exposed to an exposure energy of 20 J/c using an ultraviolet dry cleaning machine HMW-4578 (Oak Seisakusho type) (lamp: low pressure mercury lamp). was irradiated, and then immersed in water alone or in a solution of a mixture of water and the following organic solvent at 102°C for 9 hours.

As a result, the substrate on which the color filter is formed, for example, C.
It was possible to completely remove the color filter layer without damaging the surface of the CD or the aluminum wiring. For example, it has become possible to recover high-value-added substrates for solid-state imaging devices, which previously could not be recovered, without damaging the light-receiving surface or other attached parts. Since a color filter can be formed again on top, the yield of manufacturing color solid-state image sensors can be significantly improved.

Claims (1)

[Claims] 1) A color filter having a colored layer on a substrate, at least a resin layer dyed with a dye, is irradiated with ultraviolet rays, and then water alone or a mixture of water and an organic solvent is used. A method for removing a color filter, the method comprising: 2) The color filter peeling method according to claim 1, wherein the substrate is a solid-state image sensor.