JPS60261278A - Color solid-state image pickup element - Google Patents

Abstract

PURPOSE:To prevent cracks, peeling, or the like of a filter layer by providing a smooth layer consisting of a transparent resin on all of the surface of a solid- state image pickup element substrate provided with a packing layer consisting of a transparent photosensitive resin and providing the filter layer for color separation on the smooth layer. CONSTITUTION:For example, a coating layer 6 of a negative transparent photosensitive resin is formed on the rugged part of a solid-state image element substrate 1. Light is irradiated to the later in recessed parts to harden it. For the purpose of hardening the layer 6 in recessed parts, the mask where light shielding films 8 are provided in positions corresponding to projecting parts provided with wiring layers consisting of Al or the like is used as an exposure mask 7. Unhardened parts are removed by a developer after this partial exposure to form packing layers consisting of a transparent photosensitive resin in recessed parts. A transparent resin layer is provided as smooth layer 9, thereby making the surface of the substrate 1 smooth approximately ideally.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a color solid-state image sensor used in the heart of a video camera or the like.

(Prior Art to the Invention) A solid-state image sensor, in which a large number of photoelectric conversion elements are provided on a semiconductor chip such as silicon, like the compound eyes of an insect, and used in place of a conventional image pickup tube, is smaller and lighter than an image pickup tube. Due to its characteristics such as durability against vibration, it is increasingly being used as a photoelectric conversion element in video cameras.

This solid-state image sensor includes CCD method, MO8 method, 1B
There are various methods such as BD method, but basically,
The surface of the device consists of a light-receiving section consisting of a photodiode that converts light into an electrical signal, and an aluminum wiring layer for transfer, which extracts the current generated in the light-receiving section as a signal. For example, CC,
Regarding the D method, this light receiving portion is a concave portion of about 2 to 10 microns compared to the aluminum wiring layer, and it can be said that the unevenness on the surface of the solid-state image sensor is a considerably large step.

There are various methods for obtaining color information using such a solid-state image sensor, but in general, color separation of multiple sets of hues such as red, green, blue, yellow, and cyan is performed on the solid-state image sensor. This is done by forming a filter layer. The color separation filter layer is a polypeptide (e.g., gelatin) organic material layer dyed with a dye, or a high refractive index material such as titanium oxide and a low refractive index material such as silicon dioxide that are repeatedly deposited in alternating layers. materials, dyes and pigments that are vacuum-deposited to form filter layers, etc.
There are various types. The thickness of these filter layers is approximately 1
It is on the order of microns.

However, as mentioned above, the surface of a solid-state image sensor is uneven with height differences of about 2 to 2 microns, and if a color separation filter layer is formed on such an uneven surface, no matter what kind of filter layer it is, cracks will occur in the filter layer. There was a thing,
Breaking or peeling phenomena were observed.

In order to solve this problem, a coating layer of transparent resin is formed on the entire surface of the solid-state image sensor to soften the uneven surface. However, with this measure, if the coating layer is thin, the surface of the coating layer will not be completely smooth. It seems that this problem can be solved to some extent by increasing the thickness of the coating layer by applying multiple coats, but in reality, the color separation filter layer formed on the thick coating layer depends on the distance from the light receiving surface of the solid-state image sensor. As a result, the incident light is diffused by the thick coating layer or attenuated by light absorption, which causes another problem of deteriorating the spectral characteristics and sensitivity of the color solid-state image sensor.

(Problems to be Solved by the Invention) Based on the above-mentioned conventional technology, the present invention is intended to prevent cracks, breaks, peeling, etc. from occurring in the color separation filter layer formed on the solid-state image sensor. The present invention provides a new structure of a color solid-state image sensor in which the spectral characteristics, sensitivity, etc. do not deteriorate even if such a solution is taken.

(Structure of the Invention) That is, the present invention provides a filling layer made of a transparent photosensitive resin in the concave portion of a light receiving portion formed on the surface of a solid-state image sensor substrate, and a filling layer made of a transparent photosensitive resin is provided on the entire surface of the solid-state image sensor substrate provided with the filling layer. The present invention is a color solid-state imaging device characterized in that a smooth layer made of transparent resin is provided, and a color separation filter layer is provided on the smooth layer.

(Detailed description will be given below based on FIG. 1 showing an embodiment of the invention. The solid-state image sensor substrate (1) is made of a semiconductor such as silicon, and a photodiode is provided on the surface layer of the substrate (1). (2
) are formed in a desired shape such as a matrix shape or a mosaic shape to form a light receiving portion (3). On the side of the light receiving part (3), there is a wiring layer (4) made of aluminum, polysilicon, etc. that extracts the current generated by photoelectric conversion as a signal, and forms a surface higher than the light receiving part (3) as shown in the figure. are doing. A filling layer (5) made of a transparent photosensitive resin is embedded in the recess of the light receiving part (3).

The means for forming this filling layer (5) will be explained with reference to FIG. 2 of the drawing. That is, a coating layer (6) of a negative or positive transparent photosensitive resin is applied to the uneven portions of the solid-state image sensor substrate (1).
form. As shown in the figure, in this state, the coating layer (6
) has a gentle unevenness reflecting the unevenness of the solid-state image sensor substrate (1).

The thickness of the photosensitive resin coating layer (6) is preferably approximately equal to the depth of the concave portion of the light receiving portion. Next, as shown in FIG. 2(b), partial exposure is performed to leave the photosensitive resin coating layer (6) only in the recessed portions. In the illustrated example, since the photosensitive resin is of negative type, the partial exposure is performed by irradiating the photosensitive resin coating layer (6) in the recessed portion with light to cure it. For this purpose, a mask in which a light-shielding film (8) is provided at a location corresponding to a convex portion of a wiring layer made of aluminum or the like is used as an exposure mask (7). If the photosensitive resin is positive type, the light shielding film (
8) may be reversed, with the part with the light shielding film (8) and the part without it.

After performing such partial exposure, if the uncured areas (or softened areas) are removed using a developer, the image shown in Figure 2 (C) is obtained.
As shown in the figure, a transparent photosensitive resin filling layer (5) is placed in the recess.
is formed, and since the convex portions and the filling layer (5) share a surface having approximately the same height on the surface of the solid-state image sensor substrate (1), flattening can be achieved to a considerable degree.

As shown in FIG. 2(d), by further providing a transparent resin layer as a smoothing layer (9), the surface of the solid-state image pickup device substrate (1) can be made nearly ideally smooth.

At this time, since the surface to which the smooth layer (9) is applied has been planarized to a considerable extent as described above, it is sufficient that the smooth layer (9) be thin. As the material for the smooth layer (9), in addition to the usual resin composition for coating, a photosensitive resin may be used similarly to the filling layer (5).

As shown in FIG. 1, a color filter layer for color separation is formed on the smooth layer (5). As the filter layer, conventionally known filters are used, such as organic dyed filters made of polypeptide dyed with dyes, interference filters made of laminated transparent inorganic substances with different refractive indexes, and filters made by vapor-depositing dyes or pigments. The example in the figure shows an example of an organic dyed filter.In other words, after forming the red filter layer α0), an organic synthetic resin that is difficult to dye is used to prevent dye diffusion and color mixing between filter layers. uniformly apply the intermediate layer (11), then form the green filter layer (12), form the blue filter layer (04) via the second intermediate layer (13), and apply an overcoat on top of it. This is a form in which a layer (15) is formed. The form of the filter layer is of course not limited to this, and for example, each filter layer may be treated with a dye fixing agent such as tannic acid or potassium antimonyl tartrate, the intermediate layer may be omitted, or the form may be formed on an aluminum wiring layer. Various embodiments can be applied within the conventionally known range, such as first forming a black light-shielding layer and then forming a filter layer for color separation.

An example of the manufacturing method of the present invention will be described below, but of course the present invention is not limited to this.℃・0 (Example of manufacturing method) CCD type solid-state image sensor with a step difference of about 25 microns between the light receiving part and the wiring layer. A color separation filter layer was formed on the substrate by the following operation to obtain a color solid-state image sensor.

For a substrate consisting of 136 CCD type solid-state image sensors formed on a silicon wafer (diameter 1'Ocm),
A negative type photosensitive resin [FVR1oGl (parts manufactured by Fuji Yakuhin ■, manufactured by 2 people) was applied at 120 Or'pm using a rotary coater to a thickness of 25 microns. j'-F V R・
10q" is a transparent coating resin composition containing acrylic resin as a main component. After drying, using an exposure mask with a light-shielding layer formed on the portion corresponding to the convex portion of the CCI) type solid-state image sensor, exposure was performed for 15 seconds at 20 mW/7.
Only the transparent resin in the recesses was cured.

A special developer was used to remove the uncured resin coating film on the convex portions to form a filling layer. Next, acrylic transparent photosensitive resin "FVR10G" was coated on the convex parts for about 20 minutes using a rotary coating device. A smooth layer was formed by coating to a micron thickness and curing by exposing the entire surface to light.

Next, an organic dyed filter layer with an intervening intermediate layer as shown in FIG. 1 was formed in the following manner.

First, a peptide resin photosensitive material consisting of gelatin as a solid resin component of 20% by weight and ammonium dichromate 4% by weight was used as a water-soluble photosensitive material, and was coated on a smooth layer with a spin coating machine to a thickness of 10 μm. 10'00
Apply at rpm.

After drying, mask aligner-pLA-500F (Canon ■
The resin layer was subjected to alignment exposure for 20 seconds and cold water spray development to obtain a matrix-like relief pattern with a thickness of 08 μm. This was colored a first color red using a red dye solution and dyeing conditions as shown in Table 1 below to form a red filter layer.

Next, as a first intermediate layer, a coating liquid having the same composition as the undercoat layer was used and coated with a rotary coater to 3000 +-1) +1
After coating No. 1, this was heat-treated at 1.60° C. for 30 minutes to be thermally cured. After cooling, the same water-soluble photosensitive material used for the first color was applied thereon to a thickness of 08 μm,
After drying, it was exposed and developed in the same way to form a resin layer with a thickness of 065 μm.
A relief pattern of m was obtained.

This was immersed in the green dyeing solution shown in Table 1 to obtain a second color green filter layer. A second intermediate layer is coated on the dyed resin layer of the second color under the same conditions as the first intermediate layer,
Repeat in the same way as the third color, adding a blue resin layer to a thickness of 0.
A relief pattern of 8 μm was obtained, and this was colored blue with the blue liquid shown in Table 1 below to form a blue filter layer. After that, the same coating liquid as that for the smooth layer was used as an oval coat film (.01 μm). A thick coating layer was formed.

The composition and dyeing conditions (temperature and soaking time) of red, green, and blue dye solutions are shown below as an example of a dye solution, and these are suitable for forming a dyed resin layer using a pebutide resin photosensitive material. be.

Table 1 Red Color 60°C for 3 minutes Green Blue Color (Effects of the Invention) The present invention is a color solid-state image sensor as described above, and C
For an uneven surface with a considerable height difference, such as the surface of a CD solid-state image sensor, we first provided a filling layer to fill the recesses, and then provided a smooth layer over the entire surface, so the uneven surface of the solid-state image sensor is relatively smooth. Flattening is achieved by the thin resin layer, and the flattening of the particles is also close to ideal.

Therefore, in the color solid-state imaging device of the present invention, since the color filter layer for color separation is formed on the flat surface,
No defective development such as cracks, breakage, or peeling of the filter layer is observed.

Furthermore, in the present invention, since the resin layer for smoothing is thin, the extent to which the incident light is diffused or attenuated is small, and therefore the spectral characteristics and sensitivity as a color image sensor are extremely good.

As described above, it can be said that the present invention is a color solid-state image sensor that is extremely excellent in terms of quality and practicality.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view showing one embodiment of the color solid-state image sensor of the present invention, and FIG. 2 (a) to (=) form the filling layer and smooth layer of the color solid-state image sensor of the present invention. FIG. 3 is an explanatory diagram showing the process in order. (1)...Solid-state image sensor substrate (5)...Filling layer (
9)...Smooth layer 00)...Red filter layer (11)...
...Middle layer (121...Green filter layer 03)...
Second intermediate layer α force...Blue filter layer (15)...
Overcoat layer patent applicant: Toppan Printing Co., Ltd. Representative: Kazuo Suzuki

Claims (1)

[Claims] 1. A filling layer made of a transparent photosensitive resin is provided in the concave portion of the light receiving portion formed on the surface of the solid-state image sensor substrate, and a smooth layer made of transparent resin is provided on the entire surface of the solid-state image sensor substrate on which the filling layer is provided. . A can-solid-state imaging device, characterized in that a filter layer for color separation is provided on the smooth layer.