JPS5952549B2 - Color solid-state image sensor - Google Patents

Description

[Detailed description of the invention] The present invention relates to a color solid-state image sensor.

The imaging section of a solid-state color imaging device has a large number of light detection sections, and is therefore a semiconductor circuit section (abbreviated as an image sensor) made of silicon, for example.

), and three primary color (or complementary color) filters provided corresponding to the light detection section. Naturally, the structure is such that a mosaic color filter of three primary colors (or complementary colors) is arranged on each photodetecting element of the photodetecting section. The photodetection section may be made of the same base material as the semiconductor integrated circuit that forms the peripheral circuitry for operating it, or the photodetection section and other semiconductor circuit sections may be made of different types of semiconductor materials. be.
Conventionally, the way to make these solid-state color image sensors is to make the solid-state image sensor and color filter separately, and then use optical adhesive to align them with the fine pattern of the light detection part of the image sensor, and then create a mosaic color filter. A bonding method is used.

Additionally, P., L., P., Dillon et al. have proposed a method of similarly arranging a color filter on a solid-state image pickup device using an optical matching oil instead of the above-mentioned optical adhesive. However, with this type of adhesive color filter, the color filter needs to be made on a separate transparent substrate, which increases material costs.

In addition, there are various problems such as the fact that the bonding process is time-consuming.
In the present invention, color filters are directly stacked on the substrate of a solid-state image sensor. To achieve this purpose, the following water-soluble bisazide compound is used as a crosslinking agent for the filter base material (generally, protein-based organic materials such as gelatin, casein, and egg white are used).
Examples of bisazide compounds include the following.

Then, an element that becomes an impurity such as an alkali metal (Na in the above-mentioned specific example) or an alkaline earth metal in this bisazide compound is replaced with an H+ group or an NH↓ group.

This substitution can be accomplished by deionization using a cation exchange resin. The use of a protein-based organic polymer material using a water-soluble bisazide compound having sulfonic acid or an ammonium salt of sulfonic acid as a crosslinking material for the filter base material has the following advantages.

(1) To obtain the same saturated absorbance (generally referred to as the depth of staining), the objective can be achieved with a thinner film thickness than when ammonium dichromate, etc., which have been used as a crosslinking material so far, is mixed. Table 1 shows the results of comparing the film thicknesses required to obtain the same saturated absorbance.

note. (1) The film thickness is a relative value. (2) The filter base material used in the present invention is the same as in the examples described below.

(3) The solution composition for forming the filter base material used in the comparative example is as follows.

Gelatin 12%, ammonium dichromate 5% (relative to gelatin), tartrazine 1.5% (relative to gelatin), water Remainder As can be seen in these results, the film thickness is about 60% compared to the conventional example. One purpose can be achieved.

(2) Therefore, a more precise color filter pattern can be formed, and the resolution of the imaging device can be improved.

Table 2 shows the degree of decrease in transmittance between the linear filters, which should be white in nature, when linear filters are processed.

Filter width 13μm, Filter spacing 13μm This is the result.

Cy'W indicates the transmittance of cyan to white, and Y/W indicates the transmittance of yellow to white. It is understood from Table 2 that the degree of fogging is extremely small in the materials according to the present invention. (3) On the substrate of the solid-state image sensor,
Various semiconductor device parts are formed, but even if a color filter made of an organic polymer material is formed on top of the color filter, the alkali metal or alkaline earth metal contained in the bisazide contained in the filter base material cannot be converted to H+. Base, or NH!
Since it is substituted with a group, there is no adverse effect on the semiconductor device section.

Example Removal of sodium and trichlorium ions in bisazide compounds was carried out using a cation exchange resin, (DOwex5OW x 2,
This was carried out by using a Dow Chemistry Co., Ltd. column.

That is, 40 ml of the above cation exchange resin was packed into a column, and first, 11 ion-exchanged water, 2N monohydrochloric acid, ion-exchanged water, ammonium chloride (or ammonium sulfate,
5 or other inorganic ammonium salts) and then ion-exchanged water to prepare an ammonium salt type ion-exchange resin column. Add to this an azide aqueous solution (2.5%)
, and collect the ammonium salt that distills out. or,
In the above treatment, ammonium, H +
It may have a group. From the viewpoint of water solubility, ammonium salts are preferred. A photosensitive composition shown below was prepared using a crosslinking agent made of a bisazide compound from which sodium and potassium ions had been removed in this manner. FIGS. 1 to 3 are cross-sectional views of the apparatus showing each step of forming a color filter on a solid-state image sensor.

A photosensitive film is formed by uniformly drying the photosensitive composition shown above on a solid-state imaging device substrate using a spin coater. The photoelectric conversion units 8, 9, 10 and additional peripheral circuits are incorporated into this solid-state image sensor base. A color filter is formed corresponding to this photoelectric conversion section. Then,
Using the mask exposure method, only the mosaic pattern portion 2 of the first color is placed at 70,000Lx2 on the photoelectric conversion section 8 that should feel red.
Expose for 0 seconds and develop with warm water at 40° C. for 2 minutes.

Thereafter, the photoresist film other than the mosaic pattern portion 2 is removed by washing with water for 2 minutes. The mosaic pattern portion 2 is dyed with a dye having predetermined spectral characteristics, and a transparent intermediate layer (polyglycidyl methacrylate) 3 is coated on top of the mosaic pattern portion 2. FIG. 1 is a sectional view showing this state. The dyeing method may be a conventional method using an aqueous dye solution, and the dyeing conditions are as follows.

(1) Dye blended edge color Next, the photosensitive composition is similarly applied uniformly to form a photosensitive film, and the photoelectric conversion area 9 where the edge color is to be felt is exposed using a mask exposure method, developed, and washed with water. A colored mosaic pattern portion 4 is formed.

Next, the striped portion 4 is dyed with a dye having predetermined spectral characteristics, and a transparent intermediate layer 5 is coated on top of the striped portion 4. This state is shown in FIG. Further, in the same manner, the photosensitive composition is uniformly applied to form a photosensitive film, and then the photoelectric conversion portion 10 that should sense blue color is exposed to light using a mask exposure method and developed.
A colored mosaic pattern portion 6 is formed.

The striped portion 6 is dyed with a dye having predetermined spectral characteristics, and a protective film 7 is formed on the striped portion 6. In this way, it was possible to directly stack the mosaic colors and tiles on the solid-state image sensor substrate. In this way, by removing sodium and potassium, which have the most adverse effect on semiconductor devices, the life of the device can be greatly extended, and at the same time, it is safer than using ammonium dichromate as a photosensitizer. It was also possible to reduce the cost of salt, which is difficult to handle safely because it is a hazardous substance.
Of course, forming the filter directly on the semiconductor substrate is extremely useful for simplifying the process. Note that silane was added to enhance the adhesion of the azide-added gelatin photosensitive agent to the substrate.

However, it is not absolutely necessary to add silane.

[Brief explanation of drawings]

1 to 3 are cross-sectional views of an apparatus showing each step of the manufacturing process of the color solid-state image sensing device of the present invention. In the figure, 1 is the solid-state image sensor substrate, 2 is the gelatin color pattern of the first color, 3 is the intermediate layer, 4 is the gelatin color pattern of the second color and 6 is the gelatin color pattern of the third color, 5 is the intermediate layer, and 7 is the protective film layer. It is. Reference numerals 8, 9, and 10 indicate light detection units corresponding to the respective colors.

Claims (1)

[Scope of Claims] 1. A color filter having an organic polymer material layer as a dye-receiving layer is provided on a semiconductor substrate incorporating at least a photodetecting section in which a plurality of photodetecting elements are arranged, and the color filter corresponds to the photodetecting section. In the color solid-state image sensing device, the organic polymer material layer is formed of an organic polymer material containing a water-soluble bisazide compound having a sulfonic acid group or an ammonium salt of sulfonic acid as a crosslinking agent. A color solid-state image sensor. 2. The color solid-state imaging device according to claim 1, wherein the organic polymer material is water-soluble.