JPH0132677B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color image sensor in which a color filter is integrally formed on a light-receiving surface of the image sensor.

For example, in a solid-state image sensor that uses a charge transfer element such as a CCD (charge coupled device) or a BBD (bucket bridge device), a color filter is integrally formed on the light-receiving surface of the image sensor. Attempts have been made to produce color image sensors. For the applicant,
Previously, we proposed a color image sensor in which color filters were integrally formed as shown in FIG. This color image sensor has a transparent film 4 made of, for example, polyimide resin, on the light-receiving surface of the image sensor 1, so as to fill in the unevenness caused by the difference in thickness between the light-receiving portion 2 and other portions 3.
After forming and flattening the surface, a light shielding layer 5 of Al is selectively formed in order to prevent optical color mixing between each dyed layer (contamination of photons from adjacent dyed layers).
Next, a layer to be dyed, such as casein, is formed in accordance with each color on the membrane 4 corresponding to each light-receiving portion 2, and this is dyed to form a color filter consisting of dyed layers 6R, 6B, and 6G of red, blue, and green, for example. 6. In addition, when forming the blue dyed layer 6B, in order to adjust the red spectral sensitivity, the diffusion prevention treatment of the blue dye to the red dyed layer 6R is not performed, and in the formation of the next green dyed layer 6G, the green dye is blue dyed. Isolation layer 7 is formed to prevent color mixing due to diffusion into layer 6B. In this color image sensor, the uneven light-receiving surface is made flat by the film 4, so the dyed layer formed thereon does not have any breaks or cracks, and the dyed layer does not peel or fall off. There are advantages.

However, when the color filter 6 is formed through the film 4 made of polyimide resin or the like in this way, the film 4 often peels off locally during dyeing, which causes disturbances on the surface of the filter film. occurs, and the formation of a high-quality color filter is impaired. The reason for this peeling is that when patterning Al by selective etching after vapor-depositing Al to become the light-shielding layer 5 on the film 4, the lower layer Fine cracks 8 occur in the membrane 4, and when the layer 6' to be dyed is subsequently formed directly on the membrane 4 and dyed, Fig. 2B (state after staining) occurs.
As shown in , it is thought that the dyeing liquid penetrates into the crack 8, and the layer 6' to be dyed swells with the dyeing liquid, and the tension at the time of swelling acts directly on the membrane 4, causing the membrane 4 to peel off. .

In view of the above-mentioned points, the present invention prevents quality deterioration of color filters and provides an improved color image sensor.

Hereinafter, an example of a color image sensor according to the present invention will be described in detail with reference to the drawings, along with its manufacturing method. In this example, a color filter consisting of three colors of red, blue, and green is formed on the light receiving surface of a solid-state image sensor. It is.

In the present invention, first, as shown in FIG. 3A, a solid-state imaging device 1 made of a charge transfer device such as a CCD or a BBD is provided. The figure particularly shows the light-receiving surface of the image sensor, and the surface has a step difference between the light-receiving portion 2 and the other portion 3. This image sensor 1
A transparent film 4 is deposited on the light-receiving surface of the device to protect the surface, fill in irregularities, and flatten the surface. This membrane 4
As for the characteristics, it is necessary to have chemical resistance and at the same time be transparent. Generally blue (wavelength 450μm)
Since the sensitivity is poor, the film 4 is preferably made of a transparent material that does not impair this sensitivity, and a polyimide resin film can be used. In the case of polyimide resin, the blue transmittance is about 90 to 95%. This membrane 4
As a result, the unevenness of the light-receiving surface becomes flat.

Next, a light-shielding material such as Al is deposited on the entire surface of the film 4, and patterned by selective etching to form a light-shielding layer 5 of Al on the portion to be light-shielded except for the light-receiving portion 2 (FIG. 3B). .

Next, a negative-type oil-based photoresist (commercial product) mainly made of polyvinyl cinnamate, which has affinity for both the film 4 and the dyed layer to be formed later, is applied to the entire surface of the film 4, including the light-shielding layer 5. TPR),
A transparent separation layer 10 made of a negative-type acrylic polymer photoresist (trade name: FVR) or the like and impermeable to the dye solution is deposited. This separation layer 1
0, when a polyimide resin-based membrane is used as the membrane 4, the separation layer 10 is coated with the material to be dyed, for example, the casein layer 11, in order to further improve the adhesion between the membrane 4 and the separation layer 10. (Fig. 3C).

After forming the separation layer 10 on the entire surface in this way, a layer to be dyed is selectively formed on the separation layer 10 corresponding to the dyed area 2 in which the first color dyeing layer is to be formed among the plurality of light-receiving areas 2. For example, a casein layer for dyeing is formed, and this casein layer is immersed in a dyeing liquid of a first color, for example, red, to be colored to form a red dyed layer 6R. Next, a casein layer for dyeing is selectively formed in the same manner on the separation layer 10 corresponding to the light-receiving portion 2 where a second color dyeing layer is to be formed, and this is applied to a dyeing solution of the second color, for example, blue. Dipped and colored blue dyeing layer 6B
form. In this case, when dyeing blue, the blue dye is allowed to diffuse into the red dye layer 6R at the same time, thereby adjusting the spectral sensitivity of red. Next, in order to isolate the red dyed layer 6R and the blue dyed layer 6B, that is, to prevent color mixture, a transparent layer made of, for example, TPR (trade name) is applied to the entire surface of the light receiving surface including the red dyed layer 6R and the blue dyed layer 6B. After forming the isolation layer 7, a casein layer for dyeing is selectively formed corresponding to the light-receiving area 2 where the third color dyeing layer is to be formed in the same manner as above, and this is dyed with the third color green. It is immersed in a liquid and colored to form a green dyed layer 6G. Finally, a protective layer 7' made of TPR (trade name) or the like similar to the isolation layer 7 is deposited over the entire surface. In addition to casein, the above-mentioned layers to be dyed include gelatin and polyvinyl alcohol (PVA).
A layer to be dyed such as the following can be used.

Thus, as shown in FIG. 3D, a dyed filter has red, blue, and green dyed layers 6R, 6B, and 6G disposed on the light-receiving surface corresponding to each light-receiving portion 2, respectively.
In other words, a color image sensor 12 in which the color filter 6 is integrally formed is obtained.

According to the present invention described above, the separation layer 10 is formed between the layer to be dyed and the film 4 made of polyimide resin, etc., which flattens the unevenness of the light-receiving surface, so that the film 4 during dyeing is In other words, the dye solution no longer permeates into minute cracks in the film 4 (cracks generated in the patterning of the Al light-shielding layer), and the tension when the layer to be dyed swells directly acts on the film 4. do not. Therefore, separation of the film 4 from the element substrate is reliably prevented, and a high-quality color filter 6 with no disturbance in the filter film surface is formed on the light-receiving surface of the element 1. Moreover, as in the case of FIG. 1, the film 4 eliminates unevenness on the light-receiving surface, thereby avoiding breaks in the layer to be dyed and occurrence of cracks, preventing the dyed layer from peeling or falling off, and furthermore, the isolation layer 7 This also prevents color mixing (bleeding) between mutually dyed layers. Therefore, the present invention provides an excellent color image sensor having a better quality color filter without sacrificing the advantages of the conventional technology. In the above example, the present invention is applied to the case where the color filter is made up of three colors, red, blue, and green, but it is of course applicable to the case where the present invention is provided with the color filter made of other colors.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional color image sensor, FIGS. 2A and B are explanatory diagrams for explaining the present invention, and FIGS. 3A to 3D are steps showing an example of a color image sensor according to the present invention. FIG. 1 is an image sensor, 2 is a light receiving part, 4 is a transparent film,
5 is a light-shielding layer, 6R, 6B, and 6G are dyed layers, 7 is an isolation layer, and 10 is a separation layer.

Claims (1)

[Claims] 1. A film is formed on the surface of the image sensor to protect the surface, fill in irregularities, and flatten the surface, and a layer to be dyed is formed on the film with a separation layer that is transparent and impermeable to the dyeing solution. A color image sensor comprising dyed layers and a color filter formed on the image sensor.