JPS6041004A - Solid-state image pickup element - Google Patents

Abstract

PURPOSE:To easily work a color separation filter by using positive type radiation sensitive organic high polymer material for an intermediate layer and a protection layer which constitute the color separation filter, and performing the work by as many times as prescribed number of laminated layers. CONSTITUTION:A photodetection part 10 and a driving circuit part 11 are formed, and the protection layer 16 of organic high polymer material is formed on the surfaces. A layer of the base material of the color separation film is formed on a substrate 1; only a part 17 of this layer corresponding to the 1st color is cured by light irradiation and dyed with a dye having specific spectral characteristics. Then, the transparent intermediate layer 18 having resistance to dyeing is covered with organic high polymer material having radiation sensitivity characteristics different from the photosensitivity characteristics of the base material of the color separation filter. Those two protection layers 16 and 18 are developed by irradiating an unnecessary part such as a bonding part with far- ultraviolet rays. Then, the layer of the color filter base material is formed and developed to form a filter part 19 corresponding to the 2nd color, and the part is dyed with a dye having specific spectral characteristics. Then, a transparent intermediate layer 20 is formed and a desired part is removed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a solid-state image pickup device. [Background of the Invention] Conventionally, a solid-state image pickup device and a color separation filter are manufactured separately, and then optical A common manufacturing method is to bond with a commercial adhesive (Japanese Patent Publication No. 52-17375)
).

[Purpose of the invention]

An object of the present invention is to mount a color separation filter directly on the light detection section of a solid-state image sensor to improve the workability of manufacturing the device.

A second object of the present invention is to make the color separation filter in this case sufficiently accurate and of high quality.

[Summary of the invention]

The present invention uses a positive radiation-sensitive organic polymer material for the so-called intermediate layer and protective layer constituting the color separation filter, and the processing of the filter is made by stacking no more than two layers. Make it easier and improve machining accuracy.

The following radiation-sensitive organic polymer materials are useful for use in the present invention.

Non (1) Poly-alkyme methacrylate or its copolymer CH3 However, R+ is an alkyl group 1, for example, CH3°C,H.

(2) Polyglycidyl methacrylate or its copolymer CH3 1 (3) Polymethacrylamide CH3 moCH2-C+.

0NH2 (4) Polymethylimpropenylketone H3 MoCH2-C→0 OCH3 CH2 CI(3 (6) Polyisobutylene CH3 ■ So CH2-C+.

CH3 It goes without saying that positive-type radiation-sensitive organic polymer materials other than these examples may be used.

Of course, those sensitive to ultraviolet rays, electron beams, and X-rays can also be used, and in this specification, these are referred to as "radiation sensitive."

Among the radiation-sensitive materials mentioned above, for example, polyglycidyl methacrylate, polymethyl methacrylamide, and poly(methyl methacrylate)-methacryloyl chloride copolymer belonging to copolymers with polymethyl methacrylate are thermally crosslinkable additives. be.

In the case of such a material, for example, by applying the intermediate layer and heating it at a temperature sufficient to cause thermal crosslinking, the water resistance of the intermediate layer is improved and it acts more effectively as a dye-resistant layer.

If the heating temperature and time are about 200 DEG C. and about 15 minutes, polymerization due to crosslinking will proceed to a considerable extent, resulting in the above-mentioned improvement in water resistance, etc.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail according to specific examples.

1 to 4 show the manufacturing process of the color solid-state camera of the present invention. Both are cross-sectional views of the main parts of the elements. FIG. 5 is a plan view thereof.

At least a large number of photodetecting sections 10 and a drive circuit section 11 for driving them are formed on the color solid-state image sensor substrate 1. As shown in FIG. Generally, the substrate 1 is made of silicon. The optical detection section may be made of the same base material as the semiconductor integrated circuit that forms the peripheral circuitry that operates it, or it may be made of semiconductor material from tree stubble.

A layer of a base material of a color separation filter is formed to a thickness of about 0.5 to 2.5 μm on such a color solid-state image sensor substrate. This matrix is generally made of gelatin, egg white, glue, casein, gum arabic, poval, or the like, which has been made photosensitive. As for photosensitive characteristics, it is common to use a negative type and have sensitivity in the range of 365 nm to 435 nm.

By photo-curing only the first color portion 17 of this layer using a mask exposure method and developing it, only the portion 17 of the one-color separation filter base material remains. This area is stained with a dye having predetermined spectral characteristics. Note that the dyeing method may be a conventional method using an aqueous dye solution.

Note that when forming this first color filter matrix layer,
It is preferable to form a protective layer 16 of an organic polymer material on the surface of the substrate 1 to a thickness of about 0.5 to 1 μm. The surface of the substrate is further planarized by this coating of organic polymer material. This brings about the following advantages.

(1) The semiconductor device portion provided in the substrate 1 is protected from contamination such as impurities.

(2) The optical surface of the substrate 1 is flattened, making it easier to form the intermediate layer 18, the filter base material layer, etc. formed on top of the optical surface, and also reducing color mixture during dyeing, which occurs especially due to deformation of the intermediate layer. (3) In the color filter processing process, the adhesion area of impurities is reduced, which is useful for preventing contamination of semiconductor devices in the substrate.

Note that it is advantageous for later processing to use a radiation-sensitive organic polymer material for forming the above-mentioned intermediate layer and the like as the organic polymer material.

In this case, polyglycidyl methacrylate was used.

Next, a transparent dye-resistant intermediate layer 18 is formed to a thickness of 0.5 to 15 mm.
Coat to μm. This state is shown in Figure 1. The above-mentioned radiation-sensitive organic polymer material is used for this intermediate layer. In this case, it is best to select a material that has radiation sensitivity characteristics different from those of the color separation filter base material. was mentioned above.

These two protective layers (16, 18) are bonded. Exposure time is approximately 500 ms using a 3kW mercury lamp at a distance of approximately 10 am.
It was set as 1 minute.

Next, a layer of a one-color filter base material is formed, exposed by a mask exposure method, and developed to form a second color filter portion 19, which is dyed with a dye having predetermined spectral characteristics. Furthermore, a transparent intermediate layer 20 is applied.

Next, the protective film 20 is processed to remove a desired portion in the same manner as described above. Exposure time is about 30 seconds.

Note that the intermediate layer and the protective film are also made of a positive radiation-sensitive organic polymer material.

A color separation filter is formed through the above steps.

In addition, dyeing for forming a one-color filter was carried out according to the conventional method.
All you have to do is decide on the dye formulation, content, dyeing solution temperature and dyeing time.

In this case, the first color was cyan, for example, dyed with Chipa Chrome Taxiple (trade name), and the second color was dyed yellow with Kayanol Yellow NsG. In this way, the bonding butt portion and the like are opened. FIG. 5 is a plan view of the color solid-state image sensor. As shown in the figure, a photodetector 14, a circuit 15 for driving the photodetector, and a bonding section 11 are arranged in the silicon chip substrate.A color filter such as a mosaic pattern is formed in the photodetector by the method described above. has been done. The filter material in the bonding part was removed by the method described above, and the bonding butt was made to have 4 holes. Next, Au
, or Al-8i (Si content 0.5 to 1 wt%) is ultrasonically bonded to a bonding bat. Or Au
-8n (Au content: 10 wt%) may be thermocompression bonded to an Au bonding bat.

In this way, a color solid-state imaging system is completed.

As in this example, the following drawbacks can be eliminated by using a positive radiation organic polymer material as the intermediate layer and protective film of the filter, and by processing it with a laminated number of no more than two layers.

For example, (1) when forming a color filter layer, gelatin, which is the base material of the filter, is very thin and usually has a monomolecular layer, and a thin film is interposed between the protective layers and acts as an absorbing layer during exposure to prevent light exposure. It becomes difficult to process because it becomes a damage prevention layer when the developing solution penetrates into the lower layer during development. In addition, (2) improving the adhesion between gelatin and the protective layer or improving the wettability of the surface of the protective layer against water will cause the surface of the protective layer to change in quality, and the damaged layer will act as a protection against damage in the same way as a thin film of gelatin. . As color filters are processed, it becomes increasingly difficult to process the protective film. (3) When there are 3 to 5 layers, the exposure time becomes long.

The exposure time will not subside within normal economical exposure times.

There are methods such as increasing the intensity of the exposure light source or applying ultrasonic waves during development, but the ultrasonic method causes defects such as cracks in the filter. In order to increase the light source intensity, it is necessary to increase the capacity of the lamp, but since the proportion of far ultraviolet components is small, heat ray emission is a problem, and it is difficult to increase the light source intensity.

The present invention addresses the deterioration of the protective layer, takes advantage of the properties of the positive radiation-sensitive protective layer, and is economical.

Since this example is a complementary color type and a two-color type, the protective film is three layers, and this is an example in which the protective film at the bonding portion was removed by a combination of two-layer overlapping exposure and single-layer exposure processing.

In cases other than this embodiment, the protective film 16 is first processed and the Cy
A color filter of an, yellow, etc. is formed.

There is also a method of forming the final protective film 20 and processing the two layers of protective films 18 and 20 at the same time.

Also, RGB type, Cyan, Yellow, Black
In the case of multilayer color filters such as molds, the number of layers of the protective film increases, and various combinations of processing can be considered, and processing becomes possible depending on the combination.

Further, there are cases where a protective layer such as the protective film 16 on the surface of the image sensor is omitted, but even in such a case, the processing of the protective layer becomes easier depending on the combination.

Table 1 shows other specific examples of the filter base material, intermediate layer, and protective layer.

Note that the protective film is preferably of positive type. Some materials are made of materials whose color filters are altered by strong ultraviolet rays during processing, but there is no need to worry about this with positive types that are not irradiated with ultraviolet rays. [Effects of the Invention] As described above, the solid-state image sensor of the present invention has the advantage of workability. It is excellent.

[Brief explanation of the drawing]

1 to 4 are device diagrams showing a method of manufacturing a color solid-state image sensor according to the present invention, and FIG. 5 is a plan view of the color solid-state image sensor. 1...Solid-state image sensor substrate, 16...Protective film, 17.19...Color filter section, 18...
...Intermediate layer, 20...Protective film. Figure 1/i Figure 3 Figure 5//

Claims (1)

[Claims] A color separation filter section is provided on the top of a semiconductor substrate having a photodetection section in which a plurality of photodetection elements are arranged, and the color separation filter section has a desired shape and a predetermined spectral distribution. A solid-state imaging device 0 characterized in that a predetermined number of filter layers having specific characteristics and transparent positive radiation-sensitive organic polymer material layers are sequentially laminated.