JPH027041B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a color filter,
More specifically, the invention relates to improvements in the dyeing process for filter base materials. Typical conventional color separation filters are made by uniformly coating a glass substrate with photosensitive polyvinyl alcohol, greens, gelatin, etc., and photo-curing and developing only the hue of the first color using a mask exposure method. remove parts. This hue area is dyed with a dye having the required spectral characteristics. A transparent anti-color mixing layer (generally an interlayer) is then applied. The second color hue portion is also dyed using the same process to cover the intermediate layer. The third color is also dyed using the same process to form a protective film. However, color filters are generally provided with a color mixture prevention layer (hereinafter referred to as an intermediate layer) for preventing color mixture from other filters or regions. In particular, if this layer is provided around or near the filter, the intermediate layer will also be dyed during dyeing. In the case where a plurality of filters are provided in a layered manner, the dyed intermediate layer significantly reduces the light transmittance, leading to a decrease in sensitivity to ultraviolet rays. In this way, for practical filters with an intermediate layer made of a radiation-sensitive organic polymer material, the dyeing solution is adjusted under conditions that the filter is easily dyed but the intermediate layer is not. There is a need. In the past, dyeing solutions were prepared based on dyeing conditions for filters only, which resulted in extremely low manufacturing yields for practical color filters with intermediate layers or protective layers, and also made it difficult to produce filters with good optical properties. The drawback was that it was not formed. An object of the present invention is to provide a method for manufacturing a color filter that eliminates the above-mentioned drawbacks and has good optical properties, and also facilitates the processing of the above-mentioned intermediate layer or protective layer after forming the filter layer. . In order to achieve the above object, the method for manufacturing a color filter for a solid-state image sensor according to the present invention has the following features. That is, a step of providing an organic polymer material layer on the upper part of the solid-state imaging device substrate, a step of providing a filter base material layer of a desired shape on the organic polymer material layer, and a step of dyeing the filter base material layer to have a predetermined spectral characteristic. and a step of processing at least a part of the organic polymer material layer, in this order, the organic polymer material is polyglycidyl methacrylate, polymethyl methacrylate, polymethyl isopropenyl ketone, polymethyl At least one member of the group consisting of methacrylamide, polyhexafluorobutyl methacrylate, and polybutene-1 sulfone is used. In the graph, PH=6.3 at 0℃, PH=7.5 at 50℃, 75℃
The purpose is to dye the dye under the following conditions: PH=5.0 at 60°C, PH=2.0 at 60°C, and PH=2.0 at 0°C. This is the area indicated by diagonal lines in FIG. Polyglycidyl methacrylate (hereinafter abbreviated as PGMA) is a typical example of the intermediate layer of a filter and is a radiation-sensitive material.
There is. Processing of the intermediate layer or protective layer after forming the filter layer is carried out by selectively exposing the intermediate layer or protective layer to radiation, deep ultraviolet rays or ultraviolet rays, and developing. By processing in this manner, it is possible to expose, for example, the bonding pad portion of the peripheral circuit of the solid-state image sensor. Polyglycidyl methacrylate (PGMA)
Radiation-sensitive polymeric organic materials such as (abbreviated as ) are used in the first region where the pH of the dyeing solution is less than 2, and also the line connecting the dyeing solution temperature PH2.0 at 60℃ and PH5.0 at 75℃. PH5.0 in the area and temperature exceeding 75℃ and 50℃
The area that crosses the line connecting PH7.5 is stained. Furthermore, the filter base material made of a polymeric organic material such as gelatin is dyed in the region on the stronger acid (left) side of the line connecting PH6.3 at 0°C and PH7.5 at 50°C. It goes without saying that if the solution is below 0°C, it will freeze and will not be dyed, so we will not discuss it here. A pentagonal area surrounded by straight lines 61, 62, 52, and 53 (of course above 0° C.) is the range of an appropriate staining solution. The following pentagonal area is defined as the appropriate staining area. If staining is done outside this area, the intermediate layer
It also stains PGMA, deteriorating the filter properties, and having an adverse effect on radiation irradiation for processing the shape of the filter, or for processing the holes. The filter matrix material such as gelatin is dyed in the proper dyeing area, and the intermediate layer such as PGMA is not dyed in the proper dyeing area. This is because gelatin forms ionic bonds with the sulfonic groups or amino acid groups of dyes in acidic solutions, but for PGAM, the acidity is too low to form ionic bonds. Each straight line indicating the above-mentioned boundary is caused by one of these. In addition, gelatin has a high degree of swelling, about twice that of an aqueous solution for dyeing. This indicates that the dye easily penetrates into the gaps in the expanded and coarsened gelatin composition. on the other hand,
PGMA hardly swells in water, and dyes do not penetrate into it. For the above reasons, gelatin is stained and PGMA is not stained in the properly stained area. In particular, the solution temperature 40 indicated by the broken line 60 in FIG.
Staining in the range S shown at ~60°C and pH 3-5 is a very good staining area. The intermediate layer is required to have particularly high transparency, and is particularly effective when processing is carried out using exposure to light with a short wavelength. As described above, according to the present invention, when dyeing a filter base material provided with an intermediate layer, the intermediate layer can be formed extremely well without causing optical contamination such as color mixing. Since there is no optical contamination, even if multiple layers of filters are provided, the light transmittance is no longer lowered by the intermediate layer. Furthermore, since the sensitivity of the intermediate layer to ultraviolet rays does not decrease, the intermediate layer can be easily removed by irradiating ultraviolet rays when processing bonding pads on the substrate. This will be explained in detail below using examples. 2 to 4 are sectional views showing the manufacturing process of a color filter as an embodiment of the present invention. A layer of a color filter base material made of gelatin or the like imparted with photosensitivity is formed on a glass substrate 1. This layer is photocured by photocuring only the first color portion 2 using a mask exposure method. As a result, only portion 2 of the color filter matrix remains. This portion is dyed with a dye having predetermined spectral characteristics by the method described below. A transparent dye-resistant intermediate layer 5 is then applied. A thermally crosslinked or radiation-sensitive polymer material is used for this intermediate layer. Figure 2 shows this state. In addition to the above-mentioned gelatin, egg white, gris, casein, gum arabic, and poval can also be used as the filter base material. PGMA was used for the intermediate layer and protective film. In addition, the thickness of the filter base material is 0.3 to 5 μm,
The thickness of the intermediate layer is 0.3 to 1.5μm, and the thickness of the protective film is 0.5μm.
~2.0 μm. The heating temperature and heating time after applying the radiation-sensitive or thermally crosslinkable polymer material are 200° C. and 20 minutes, respectively. The dyeing solution for color filter formation is as follows. Usually one color is chosen. (a) Dye formulation Green Chrysophene yellow
Yellow) 0.15wt% Lissamine Green
0.8wt% Acetic Acid 0-0.5wt% Water Blue Color Methyl Blue 1wt% Acetic Acid 0-0.5wt% Water Red Color Diacid 11 (Diacid11 Fast Red 3BL)
0.3wt% Kayanol Yellow N5G
N5G) 0.2wt% Acetic Acid 0-0.5wt% Water (b) Staining conditions Temperature Time Green 0-74℃ 2 minutes Blue 0-75℃ 1 minute Red 0-75℃ 2 minutes Use acetic acid to adjust the hydrogen index. there was. The relationship between acetic acid concentration and hydrogen index is shown in Table 1, and adjustments were made using this as a guide. Furthermore, when obtaining a high hydrogen index, acetic acid, ammonia, etc. are used in combination. PGMA is not stained at all by the staining solutions of the above colors. This is because the epoxy ring of PGMA has a pH

[Table]
This is because from PH2 to PH7, it remains closed and does not open. This is because the epoxy ring of PGMA opens for the first time in a strong acid with a pH of less than 2 and reacts with the sulfonic acid of the dye, resulting in dyeing. In general, radiation-sensitive polymer materials and thermally crosslinkable polymer materials do not swell with water, so they are not dyed. Next, if necessary, a layer of color filter base material is formed in the same manner as shown in FIG. 3, and exposed using a mask exposure method.
A second color filter portion 3 is formed by development and dyed with a dye having predetermined spectral characteristics. Since it is dyed in the dye solution mentioned above, the intermediate layer 5 is not dyed and only the filter portion 3 is dyed. Thereafter, the same procedure is repeated to form and dye the color filter 4 as shown in FIG. 4, and to form the protective film 7.
This protective film 7 may also be made of the aforementioned PGMA. A three-color filter is formed through the above steps. In addition to the above-mentioned examples, the following radiation-sensitive polymer materials for the intermediate layer may be used in the same manner. Polymethyl methacrylate, polymethyl isopropenyl ketone, polymethyl methacrylamide,
Poly(hexafluorobutyl methacrylate), polybutene-1 sulfone A thermally crosslinkable polymeric material may be added or mixed with the above-mentioned radiation-sensitive polymeric material for use in the same manner. Examples of such thermally crosslinkable polymer materials include the following. Epoxidized 1,4-polybutadiene Epoxidized polyisoprene Epoxidized polybutadiene Polyacrylamide FIGS. 5 to 8 show the manufacturing process of a color solid-state imaging device as another embodiment of the present invention.
Both are cross-sectional views of the main parts of the elements. FIG. 9 is a plan view thereof. The color solid-state image sensor substrate 21 includes a large number of light detection units 10 and a drive circuit unit 11 that drives them.
is formed at least. Generally, the substrate 21 is made of silicon. The photodetector may be made of the same base material 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. When forming the first color filter base material layer, it is preferable to form a film of an organic polymer material on the surface of the substrate 21 to a thickness of about 0.5 to 1 μm, if necessary. The surface of the substrate is further planarized by this coating of organic polymer material. 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. A layer of a base material of a color separation filter is formed to a thickness of about 0.3 to 2.5 μm on such a color solid-state image sensor substrate. In addition to the aforementioned gelatin, this base material includes egg white,
Griyu, casein, gum arabic and poval (polyvinyl alcohol, commonly abbreviated as PVA)
Materials that are made photosensitive are used. 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 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 method using an aqueous dye solution described below. Next, a transparent dye-resistant intermediate layer 5 is formed with a thickness of 0.3~
Coat to 1.5μm. FIG. 5 shows this state. The aforementioned radiation-sensitive organic polymer material is used for this intermediate layer. In this case, it is preferable to select a material having radiation sensitivity different from the photosensitivity of the color separation filter base material. Next, as shown in FIG. 6, 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. Stain using the staining method described below. Furthermore, a transparent intermediate layer 6 is coated. Furthermore, as shown in FIG. 7, 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. Through the above steps, three color separation filters are formed. In addition, dyeing for forming a color filter may be performed by appropriately determining the dye formulation, content, temperature of the dyeing solution, and dyeing time. Table 2 shows specific examples of the filter base material, intermediate layer, and protective layer.

[Table] Absorbed.
Further, examples of staining conditions are shown below. (1) Dye combination Green Color Sirius Yellow GC
0.8wt% Lissamine Green V
0.4wt% Acetic acid 0.0003~0.15wt% Water Blue Methyl Blue 1wt% Acetic acid 0.0003~0.15wt% Water Red Color Poncean S 0.3wt% Kayanol Yellow N5G
N5G) 0.08wt% Acetic Acid 0.0003-0.15wt% Water (2) Dyeing temperature, time Green 40-60℃, 2 minutes Blue 40-60℃, 1 minute Red 40-60℃, 2 minutes The relationship is as follows. 1wt
PH2.3 at %, 2.9 at 0.1wt%, 3.5 at 0.01wt%,
It is 4.1 at 0.001wt%. Based on this, the desired pH
is obtained. The staining solution is not limited to acetic acid as long as it is acidic. Not only hydrochloric acid, sulfuric acid, oxalic acid, and hydrofluoric acid, but also organic acids such as tartaric acid and sulfonic acid can be similarly used. In that case, it goes without saying that the pH is adjusted as appropriate. Further, among the radiation-sensitive materials mentioned above, for example, polymethyl methacrylate-methacryloyl chloride copolymer, which belongs to polyglycidyl methacrylate, polymethyl methacrylamide, and copolymers with polymethyl methacrylate, is also a thermally crosslinkable material. In the case of such a material, by heating the intermediate layer at a temperature sufficient to cause thermal crosslinking after coating, the water resistance of the intermediate layer is improved and it acts more effectively as a stain-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. A mask is applied leaving desired parts of the color solid-state image sensor substrate 21, such as the bonding pad part 12, and exposed to ultraviolet light. The exposure conditions are as shown in Table 1. If the light source is for far ultraviolet light, a Xe-Hg lamp is suitable. Next, by developing the three-layer laminated material for forming the filter, a desired portion is removed using an organic solvent. As such an organic solvent, a mixed solution of methyl ethyl ketone and ethanol is used. The bonding pad portion is thus opened. FIG. 9 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, a bonding section 12, etc. 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-Si13 (Si content 0.5 to 1 wt%) is ultrasonically pounded onto the bonding pad. Alternatively, Au-Sn (Au content 10wt%) may be thermocompression bonded to an Au bonding pad. In this way, a color solid-state image sensor is completed. In this way, since the intermediate layer is not dyed at all, the translucency is nearly 100%, making it possible to expose to deep ultraviolet light of 220 nm. With conventional methods, there is already a 20% light loss in visible light, and more than 50% light loss in ultraviolet light, making it difficult to thoroughly irradiate the inside of a PGMA layer with a thickness of 1.5 μm or more. Therefore, it was not possible to make an accurate perforation. In the embodiment of the present invention, the color filter is formed using the three primary colors of light, red, blue, and green, but the same effect can be achieved using the three primary colors of red, blue, and yellow. The same applies even if there are two colors or four or more colors. Furthermore, the same process could be performed by forming a color filter using complementary colors such as magenta, cyan, and yellow. FIG. 10 shows an example of a complementary color filter. The manufacturing method and symbols are the same as in the previous embodiments, so detailed explanations will be omitted. The difference is the first
The color filters 102 and 103 are both cyan. Further, the second color filters 105 and 106 are both yellow. Green color is sensed in the area where cyan color 103 and yellow color 105 overlap. Note that 101 is a leveling film. As described above, there are various types and combinations of color filters, but they do not deviate from the present invention. In addition to optical processing, these can also be provided with appropriate filters by electrical signal processing, etc., and can be equipped with an imaging function in exactly the same way as in the case of ordinary three primary colors. Furthermore, some solid-state image sensing devices have a structure as shown in Japanese Patent Laid-Open No. 10751/1982, but it is of course possible to apply the present invention to such a semiconductor substrate and provide a collar and a filter.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the scope of application of the present invention, FIGS. 2 to 4 are schematic manufacturing process diagrams of a color filter as an embodiment of the present invention, and FIGS. 5 to 8 and FIG. 10 is a schematic manufacturing process diagram of a color filter as another embodiment of the present invention, and FIG. 9 is a plan view of a solid-state image sensor as an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Glass substrate, 2-4... Filter base material, 6... Intermediate layer, 7... Protective layer.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a color filter for a solid-state image sensor, comprising: providing an organic polymer material layer on an upper part of a solid-state image sensor substrate; and forming a filter matrix having a desired shape on the organic polymer material layer. the step of providing a material layer, the step of dyeing the filter base material layer to have predetermined spectral characteristics, and the step of processing at least a part of the organic polymer material layer, in this order, the organic polymer material layer The material is at least one member of the group consisting of polyglycidyl methacrylate, polymethyl methacrylate, polymethyl isopropenyl ketone, polymethyl methacrylamide, polyhexafluorobutyl methacrylate, and polybutene-1 sulfone, and the filter matrix layer is dyed. The process of
7.5, PH=5.0 at 75℃, PH=2.0 at 60℃ and PH=2.0 at 0℃
The step of processing at least a part of the organic polymer material layer is carried out under conditions that satisfy the conditions within the area surrounded by the straight line connecting each point of PH = 2.0, and the step of processing at least a part of the organic polymer material layer is performed on the organic polymer material layer. 1. A method for manufacturing a color filter for a solid-state imaging device, comprising the steps of selectively exposing to radiation, far ultraviolet rays, or ultraviolet rays, and developing. 2 After the step of dyeing the filter base material to a predetermined spectral characteristic, the step of providing another organic polymer material layer covering the filter base material layer, and processing at least a part of the organic polymer material layer. 2. The method of manufacturing a color filter for a solid-state image sensor according to claim 1, wherein at least a part of the other organic polymer material layer is also processed. 3. For a solid-state imaging device according to claim 1 or 2, wherein the filter base material uses at least one member of the group consisting of gelatin, egg white, gris, casein, gum arabic, and poval. Method of manufacturing color filters. 4. The solid-state image sensor substrate is a semiconductor substrate having at least a photodetection section in which a photodetection element is disposed and a peripheral circuit for operating the photodetection section, and the organic polymer material layer above the peripheral circuit and the other 4. A method for manufacturing a color filter for a solid-state imaging device according to claim 2 or 3, characterized in that an organic polymer material layer is processed.