JPH0582561B2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention]

The present invention relates to a method of manufacturing a color solid-state image sensor in which a color separation filter is directly mounted on a photodetector.

[Background of the invention]

Conventionally, a common manufacturing method is to separately manufacture a solid-state image sensor and a color separation filter, and then bond them together using an optical adhesive or the like while aligning the two.
Also, instead of optical adhesive, optical matching
Examples of using oil have also been reported. Further, a method for manufacturing a polychromatic optical filter is disclosed in Japanese Patent Application Laid-Open No. 53-99822, and a method for manufacturing a color separation filter is disclosed in Japanese Patent Application Laid-open No. 147823-1989. There is no mention of providing it directly. Further, although a color imaging device and a method for manufacturing the same are disclosed in Japanese Patent Application Laid-Open No. 53-47282, there is no mention of radiation-sensitive materials at all. Regarding the composition to be copied, Japanese Patent Application Laid-Open No. 50-83425
Although the publication discloses radiation-sensitive materials in the publication, these are merely techniques related to containers and plywood.

[Purpose of the invention]

A first 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 create a color separation filter that does not cause color mixture with sufficient accuracy and high quality.

[Summary of the invention]

The above purpose is to form a plurality of photodetecting parts on a substrate, to form a flattening film made of an organic polymer material having a film thickness in the range of about 0.5 μm to 1 μm on this substrate, and then to apply a plurality of dyeing filters. This is accomplished by layer deposition to form a color separation filter. In particular, by using a radiation-sensitive organic polymer material as the so-called intermediate layer or protective layer constituting the color separation filter, the manufacturing process of the solid-state imaging device can be simplified. Furthermore, it is more preferable that the organic polymer material described above has thermal crosslinkability. This is useful for strengthening intermediate layers used in the laminated structure of color separation filters. Furthermore, it is extremely advantageous for the radiation-sensitive organic polymer material to be of a so-called positive type in terms of process simplification. Even if it has negative radiation sensitivity, this property can be used for processing the filter section. However, as each intermediate layer is formed, it becomes necessary to perform crosslinking by exposing to a predetermined radiation, which increases the number of steps. Of course, even if a positive radiation-sensitive organic polymer material is used, each of the intermediate layers described above may be formed and exposed to a predetermined radiation, and then developed and subjected to the desired processing. Of course, it is okay to do so. When each layer is processed, the number of steps is the same as in the case of negative molding. However, even in this case, the positive type has the following advantages. That is, in the case of a positive type, a portion of the organic polymer material layer to be removed is exposed to radiation, whereas in the case of a negative type, a portion of the organic polymer material to be left is exposed to radiation. Naturally, the color separation filter base material is the part where the layer of the organic polymer material remains. Therefore, in the case of a negative type, the color separation filter base material is also irradiated with exposure radiation several times, which affects the deterioration of the filter characteristics. In the case of positive type, there is no such effect at all. Furthermore, in many cases, the filter base material is also used by imparting photosensitivity, but in this case, it is preferable that the photosensitivity characteristics of the filter base material and the optical characteristics of the materials of the intermediate layer and the protective layer are different. When processing the filter base material, it is necessary not to affect the materials of the intermediate layer and protective layer that exist below it. The radiation-sensitive organic polymer materials useful in the present invention include the following. (1) Poly alkyl methacrylate or its copolymer

[Formula] However, R is an alkyl group, for example, CH ₃ ,
C ₄ H ₉ (2) Polyglycidyl methacrylate or its copolymer

【formula】 (3) Polymethacrylamide

【formula】 (4) Polymethylisopropenylketone

【formula】 (5) Poly(butene-1 sulfone)

【formula】 (6) Polyisobutylene

[Formula] It goes without saying that radiation-sensitive organic polymer materials other than these examples can be used. Of course, as the radiation-sensitive organic polymer material, those sensitive to ultraviolet rays, electron beams, X-rays, etc. can be used.
As used herein, the term "radiation sensitivity" includes these various types.

[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 image sensing device of the present invention. Both are cross-sectional views of the main parts of the elements. FIG. 5 is a plan view thereof. The color solid-state image sensor substrate 1 is provided with at least a large number of photodetecting sections 10 and a drive circuit section 15 for driving them. Note that the semiconductor substrate 1
The detailed structure inside has been omitted. Generally board 1
is made of silicon. The photodetector may be made of the same substrate as the semiconductor integrated circuit that forms the peripheral circuitry for operating the photodetector, or may be made of a different type of semiconductor material. 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 the color solid-state image sensor substrate. This matrix is generally made of gelatin, egg white, green, casein, poval, or the like, which has been made photosensitive. As for photosensitive characteristics, it is common to use a negative type and have sensitivity between 365 nm and 435 nm. By photo-curing and developing only the first color portion 2 of this layer using a mask exposure method, only the portion 2 of the color separation filter base material remains. This area is dyed with a dye having predetermined spectral characteristics. Note that the dyeing method may be a conventional method using an aqueous dye solution. In addition, when forming the layer of the filter base material of the first color, it is preferable to form a film of an organic polymer material on the surface of the substrate 1 to a thickness of about 0.5 to 1 μm. If the thickness is 0.5 μm or less, it cannot be sufficiently flattened, and if the thickness is 1 μm or more, it takes time to form and process, which is not practical. 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) By setting the film thickness to about 0.5 μm or more, the surface of the substrate 1 is flattened, making it easier to form the intermediate layer, filter base material layer, etc. formed on the top thereof, and especially the intermediate layer. It is possible to prevent color mixing during dyeing that occurs due to deformation of the material. Also,
By setting the thickness to 1 μm or less, it is possible to prevent deterioration of the filtering effect due to the wraparound of light from adjacent filters. (3) In the color filter processing process, the area on which impurities adhere is reduced, which is useful for preventing contamination of semiconductor devices on 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. Next, a transparent dye-resistant intermediate layer 5 is formed to a thickness of 0.5~
Coat to 1.5μm. FIG. 1 shows this state. The aforementioned radiation-sensitive organic polymer material is used for this intermediate layer. In this case, as described above, it is preferable to select a material having radiation sensitivity characteristics different from those of the color separation filter base material. Next, as shown in FIG. 2, a layer of color filter base material is formed, exposed using a mask exposure method, and developed to form a second color filter portion 3, which has predetermined spectral characteristics. Dye with dye. Furthermore, a transparent intermediate layer 6 is coated. Furthermore, as shown in FIG. 3, a color filter 4 is formed and dyed, and then a protective film 7 is formed. Note that the intermediate layer 6 and the protective film 7 are also made of the same radiation-sensitive organic polymer material as the intermediate layer 5.

[Table] Contained.
Through the above steps, three color separation filters are formed. In addition, dyeing for forming a color filter may be performed by determining the dye preparation, content, temperature of the dyeing solution, and dyeing time according to conventional methods. Table 1 shows specific examples of the filter base material, intermediate layer, and protective layer. Further, examples of staining conditions are shown below. (1) Dye-containing green Sirius Yellow GC 0.8wt% Lissamine Green V 0.4wt% Acetic acid 2wt% Methyl Blue Acetic acid 2wt% Water Red Poncean S 0.08wt% Kayanol Yellow N5G Acetic acid 2wt% Water (2) Dyeing temperature, time Green Color 40℃, 2 minutes Blue Color 40℃, 1 minute Red Color 40℃, 2 minutes Among the radiation-sensitive materials mentioned above, for example, polymethyl methacrylate, which belongs to polyglycidyl methacrylate, polymethyl methacrylamide, and copolymers with polymethyl methacrylate.
Methacryloyl chloride copolymer is a thermally crosslinkable material. For such materials, after applying the intermediate layer,
By heating at a temperature that causes thermal crosslinking, the water resistance of the intermediate layer is improved and it functions more effectively as a dye-resistant layer. If the heating temperature and time are 200° C. for about 15 minutes, polymerization due to crosslinking will proceed to a considerable extent, resulting in the above-mentioned improvement in water resistance, etc. This heat treatment is usually performed after forming each intermediate layer and the like. Bonding of color solid-state image sensor substrate 1
A mask is applied leaving desired parts, such as the patch part 12, and exposed to ultraviolet light. The exposure conditions are as shown in Table 1. If far ultraviolet light is used as the light source,
A Xe-Hg lamp (1KW) is suitable. The desired portions are then removed by developing the three layers of laminated material for forming the filter. In this way, a desired portion such as a bonding pad portion is opened. FIG. 5 is a plan view of the color solid-state image sensor. As shown in the figure, a photodetecting section 14, a circuit 15 for driving the photodetecting section, and a bonding section 12 are arranged in a silicon chip substrate. A color filter, such as a mosaic pattern, is formed in the light detection section by the method described above. The filter material in the bonding area was removed in the manner described above, leaving the bonding pad exposed. Next, Au or Al-Si (Si content 0.5~1wt)
%) to the bonding pad. Alternatively, Au-Si (Au content 10wt%) may be thermocompression bonded to an Au bonding pad. In this way, a color solid-state image sensor is completed. In the above specific example, processing of the bonding pad part 12, etc. on the radiation-sensitive material layer consists of laminating (1) a film formed on the surface of the semiconductor substrate 1, (2) each intermediate layer, and (3) a protective film, etc. Although the post-processing treatment is carried out, it goes without saying that the post-processing treatment may be performed for each layer or, for example, for every two layers.

【Effect of the invention】

According to the present invention, it is possible to directly mount a color separation filter on a solid-state image sensor, and it is possible to improve the workability of manufacturing the device. Furthermore, a color separation filter without color mixing can be provided with high precision and high quality.

[Brief explanation of drawings]

1 to 4 are sectional views of the color solid-state image sensing device according to the present invention, and FIG. 5 is a plan view of the color solid-state image sensing device. DESCRIPTION OF SYMBOLS 1... Solid-state image sensor substrate, 2, 3, 4... Color filter part, 5, 6... Intermediate layer, 7... Protective film.

Claims (1)

[Claims] 1. A step of forming a plurality of photodetectors on a substrate;
Approximately 0.5 μm to 1 μm on the substrate with the photodetector
a step of forming a flattening film made of an organic polymer material having a film thickness in the range of , and a step of forming a first dyeing filter above a predetermined photodetection section of the photodetection section via the planarization film. and forming an intermediate layer on the substrate having the first dyeing filter;
A method for manufacturing a solid-state image sensing device, comprising the step of forming a second dyed filter above the photodetecting section adjacent to the predetermined photodetecting section via the intermediate layer. 2. The method for manufacturing a solid-state imaging device according to claim 1, wherein the intermediate layer is a radiation-sensitive organic polymer material layer. 3. The method of manufacturing a solid-state image sensor according to claim 1 or 2, wherein the intermediate layer has a thickness of 0.5 μm to 1.5 μm. 4 The first staining filter mentioned above is from 0.5 μm.
A method for manufacturing a solid-state image sensor according to any one of claims 1 to 3, characterized in that the solid-state image sensor has a thickness of 2.5 μm.