JP2697002B2 - Method for manufacturing color solid-state imaging device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color solid-state imaging device, and more particularly to a method for manufacturing a color solid-state imaging device with improved color reproducibility.

[Conventional technology]

The color solid-state imaging device separates light incident through an optical system of a camera into red, blue, green, or complementary colors thereof, and extracts a color signal as an electric signal.

A conventional method for manufacturing this type of color solid-state imaging device is described in the third section.
This will be described with reference to FIGS.

First, the light receiving section 2 for converting incident light into an electric signal is formed on the surface of the semiconductor substrate 12. Note that the light receiving section 2 is connected by a transfer electrode (not shown). Next, an aluminum light-shielding film 4 having an opening at a portion corresponding to the light receiving section 2 is formed on the substrate with an interlayer film 3 interposed therebetween. A transparent polymer resin such as polyglycidyl methacrylate (PGMA), polymethyl methacrylate (PMMA), or GCM is formed as an intermediate layer 5 thereon, and a water-soluble resist is applied to a position corresponding to the light receiving unit 2 by a spinner. Perform patterning. Examples of the water-soluble resist include proteins such as gelatin, casein, and glue, and those obtained by adding dichromate to polyvinyl alcohol. This water-soluble resist is dyed with a magenta dye to form a magenta dyed layer 6 (FIG. 3A). Then,
An intermediate layer 5 is formed, a cyan dye layer 7 is formed at a predetermined position (FIG. 3 (b)), and a yellow dye layer 10 is formed by repeating this process (FIG. 3 (c)). Transparent polymer resin film
11 is formed (FIG. 3D).

FIG. 2 shows an example of a color filter array of a color solid-state imaging device. Generally, a green pixel is formed by superposing a cyan dye layer and a yellow dye layer.

[Problems to be solved by the invention]

The conventional color solid-state imaging device described above has a structure in which green pixels are formed by superimposing a cyan dye layer and a yellow dye layer. By the way, when forming the yellow dyed layer, since the cyan dyed layer has already been formed on the green pixel, it is raised as compared with the yellow pixel. Normally, spinner application of resist on steps
Since the surface is formed so as to be planarized, the film becomes thinner at the protruding portion, and the film becomes thicker at the opposite portion.
Therefore, the yellow dyed layer on the green pixel has a smaller thickness than the yellow dyed layer on the yellow pixel. Since the dye transmittance greatly depends on the film thickness, as shown in FIG. 4, the near ultraviolet region (400 nm to 500 nm) of the spectral characteristics of the green pixel and the yellow pixel, which should originally match, does not match, and the color reproducibility deteriorates. There is a disadvantage of doing so.

[Means for solving the problem]

In the method for manufacturing a color solid-state imaging device according to the present invention, an intermediate layer is applied to a surface of a semiconductor substrate on which a plurality of photoelectric conversion regions are formed, and a film to be dyed is applied and patterned on the intermediate layer. The process of forming a color filter film by sequentially stapling with a specific dye and forming a color filter film by dyeing with a specific dye to form a dye layer is performed, and a filter is formed by stacking a plurality of different color filter films. In the method for manufacturing a color solid-state imaging device including a step, a plurality of dyed layers of at least one color filter film are divided into two or more groups, and the dyed films are separately applied and patterned, and then dyed. It is to form.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

1 (a) to 1 (d) are cross-sectional views of a semiconductor chip arranged in the order of steps for explaining an embodiment of the present invention.

First, similarly to the conventional color solid-state imaging device, a light receiving section 2 is formed on the surface of a semiconductor substrate 1, and an interlayer film 3 and an aluminum light shielding film 4 are formed thereon. Next, PGMA is applied by spinner, and thermally cured at 140 ° C. for 30 minutes to form an intermediate layer 5-1.
To form Subsequently, gelatin containing 10% ammonium dichromate is formed to a thickness of 0.8 μm by spinner coating, prebaked at 70 ° C. for 10 minutes to form a film to be dyed, and then using a high-pressure mercury lamp. Expose. Then, it is immersed in pure water for 1 minute to form a predetermined pattern. Further, the dyed layer is immersed in a magenta dyeing solution at 60 ° C. for 2 minutes to form a magenta dyed layer 6. 0.8μm of PGMA on the top
Then, a cyan dyed layer is formed to a thickness of 0.8 μm in the same manner as the magenta dyed layer (FIG. 1A). Further, 0.8 μm of PGMA is formed to form the intermediate layer 5-3.
And Next, gelatin is spinner coated to form a film to be dyed having a thickness of 0.8 μm, and the film is exposed so as to leave a pattern only on the yellow pixels, and developed to form a first yellow dyed layer 8. Figure (b). Thereafter, gelatin is applied again by spinner, and applied to the green pixels so as to have a thickness of 0.8 μm, and the second yellow dyed layer 9 is formed while remaining on the green pixels (FIG. 1 (c)). this
Immerse in a yellow dyeing solution at 60 ° C for 10 minutes to form a yellow dye layer
Form 10. Finally, PGMA is spin-coated to a thickness of 2.0 μm to flatten the surface and form a transparent polymer resin film 11 (FIG. 1 (d)).

Since the yellow dyed layer is formed by patterning twice, the film thickness can be made uniform regardless of the shape of the base. For this reason, since the dyeing transmittance of the yellow dye layer on the green pixel and the yellow dye layer on the yellow pixel match, the near-ultraviolet region of the spectral characteristics of the green pixel and the yellow pixel in FIG. The reproducibility is greatly improved.

〔The invention's effect〕

As described above, when forming a color filter by laminating a color filter film composed of an intermediate layer and a dye layer, the present invention divides the color filter film of the upper layer into two groups according to the presence or absence of the lower dye layer. By separately forming the films to be dyed, a uniform filter can be formed, and thus there is an effect that a color solid-state imaging device with good color reproducibility can be obtained.

[Brief description of the drawings]

1 (a) to 1 (d) are longitudinal sectional views of semiconductor chips arranged in the order of steps for explaining one embodiment of a method for manufacturing a color solid-state imaging device according to the present invention, and FIG. FIGS. 3A to 3D are block diagrams showing an example of a color filter array, FIGS. 3A to 3D are cross-sectional views of semiconductor chips arranged in the order of steps for explaining a conventional method of manufacturing a color solid-state imaging device, and FIG. FIG. 4 is a spectral characteristic diagram of the color solid-state imaging device of FIG. 1 ... Semiconductor substrate, 2 ... Light receiving section, 3 ... Interlayer film, 4 ...
... Aluminum light-shielding film, 5-1 to 5-3 ... Intermediate layer, 6
... Magenta dyed layer, 7... Cyan dyed layer, 8.
Yellow dyeable layer, 9... Second yellow dyeable layer,
10 ... Yellow dyed layer, 11 ... Transparent polymer resin film.

Claims (1)

(57) [Claims] An intermediate layer is applied to a surface of a semiconductor substrate on which a plurality of photoelectric conversion regions are formed, and a film to be dyed is applied and patterned on the intermediate layer, and stapled in a predetermined arrangement. Thereafter, a step of forming a color filter film by sequentially dyeing with a specific dye to form a dye layer is performed a plurality of times,
A method for manufacturing a color solid-state imaging device including a step of forming a filter by laminating a plurality of different color filter films,
A color solid-state imaging device characterized in that at least one of the plurality of dye layers of the color filter film is divided into two or more groups, a film to be dyed is separately applied, patterned, and then dyed, and then formed by dyeing. Production method.