JPH06120461A - Solid-state image sensing device - Google Patents

Abstract

PURPOSE:To eliminate incident light reflection between the layers of a solid-state image sensing device which has the multi-layer film on a semiconductor substrate and prevent sensitivity deterioration, image deterioration, etc. CONSTITUTION:When a filter film formed of a multi-layer composed of a planarization layer 4, a color filter layer 5, an intermediate layer 6, etc., is provided on the light receiving part 2 of a semiconductor substrate 1, the whole filter film is formed of material that has the same refractive index. When a micro lens layer 7 is provided on the light receiving part 2 of the semiconductor substrate 1 through an intermediate film composed of the planarization layer 4, the color filter layer 5, the intermediate layer 6, etc., the micro lens layer 7 and the intermediate layer are formed of material that has the same refractive index. Since incident light reaches the light receiving part 2 without reflecting on the interfaces of each layer, the deterioration of the sensibility of the solid- state image sensing device, image deterioration due to the incidence of the re-reflected light on other light receiving parts and sensitivity variation due to the nonuniformity of the pattern of each layer are effectively prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device in which a filter layer or a microlens layer is provided on a semiconductor substrate, and more particularly to measures for preventing reflection at the interface between layers.

[0002]

2. Description of the Related Art In recent years, as a method of forming a color filter in a solid-state image pickup device, a method of forming it directly on a wafer (on-chip filter) has become mainstream.

The solid-state image pickup device will be described below.

FIG. 4 is a sectional view of a conventional solid-state image pickup device. 1 is a semiconductor substrate made of silicon, 2 is a light receiving portion made of a photodiode, 3 is a light shielding portion made of aluminum, and 4 is made of an acrylic transparent resin. A flattening layer, 5 is a color filter layer made of gelatin resin and dyed in a desired color, 6 is an intermediate layer made of acrylic transparent resin, 7
Is a microlens layer made of phenolic resin.

That is, light incident not only on the light receiving portion 2 but also on the light shielding portion 3 is condensed through the microlens layer 7, passes through the intermediate layer 6, and has a desired wavelength. Only the light passes through the color filter layer 5 and further through the flattening layer 4, and is incident on the light receiving portion 2. The light incident on the light receiving section 2 is converted into electric charges according to the amount thereof.

[0006]

However, in the above-mentioned conventional structure, since the materials for forming the flattening layer, the color filter layer, the intermediate layer and the microlens layer have different refractive indexes, the microlens layer, the intermediate layer and the intermediate layer are different from each other. Part of the incident light is reflected at the interface between the layer and the color filter layer,
There is a problem that the amount of light incident on the light receiving portion is reduced.

The action of reducing the light quantity will be described. Generally, the greater the angle of incidence, the greater the reflectance. For example, in the configuration of the conventional solid-state imaging device shown in FIG. 4, the refractive index of the phenol resin forming the microlens layer is 1.560, and the refractive index of the acrylic transparent resin forming the intermediate film is 1. .495 and Snel
According to the law of l, if the incident angle of light entering the interface between the microlens layer 7 and the intermediate layer 6 exceeds 73.4 °, total reflection occurs at the interface. That is, particularly when the diaphragm of the lens of the video camera is opened, the proportion of incident oblique light increases, which may reduce the amount of incident light, that is, may deteriorate the sensitivity of the solid-state imaging device. Further, if the reflected light is re-reflected at another interface and is incident on another light receiving portion, image deterioration may occur and S / N may deteriorate.

In addition, if the pattern shapes of the flattening layer 4, the color filter layer 5, the intermediate layer 6 and the microlens layer 7 are non-uniform, the directions of reflection and refraction at the interfaces of the respective layers also become non-uniform, Since the amount of light incident on the light receiving portion is also nonuniform, there is a problem in that sensitivity varies.

The present invention has been made in view of the above points, and an object thereof is to provide a microlens layer and an intermediate layer in a solid-state imaging device in which a microlens or a color filter layer is formed on a semiconductor substrate. In order to effectively prevent the deterioration of sensitivity, the deterioration of image and the fluctuation of sensitivity by taking measures to prevent the reflection of incident light at the interface between the color filter layer and the flattening layer.

[0010]

Means for Solving the Problems To achieve the above object, the means of the present invention as defined in claim 1 is formed on a semiconductor substrate, a light receiving portion formed on the semiconductor substrate, and a light receiving portion formed on the light receiving portion. It is assumed that the solid-state imaging device has a filter film formed of a multilayer film.

The filter film is formed of a material having the same refractive index.

According to a second aspect of the present invention, a means includes a semiconductor substrate, a light receiving portion formed on the semiconductor substrate, and a microlens layer formed on the light receiving portion via an intermediate film. An imaging device is assumed.

The microlens layer and the intermediate layer are formed of materials having the same refractive index.

According to a third aspect of the present invention, a means for forming a semiconductor substrate, a light receiving portion formed on the semiconductor substrate, a filter film formed on the light receiving portion, and a filter film formed on the filter film are provided. A solid-state imaging device having a microlens layer is assumed.

The filter film and the microlens layer are integrally formed using materials having the same refractive index.

[0016]

With the above construction, in the invention of claim 1, when light is incident on the solid-state image pickup device, a multi-layer including a flattening layer for filling irregularities between the light receiving portion on the semiconductor substrate side and the color filter is provided. Since the filter film made of a film is formed of a material having the same refractive index, the incident light reaches the light receiving portion without being reflected at the interface between the layers.
Therefore, the incident light is efficiently taken in, the sensitivity deterioration of the solid-state imaging device is prevented, and the image deterioration caused by the light reflected at the layer interface being re-reflected at other interfaces is also prevented. . Further, even if the pattern of each layer becomes non-uniform, reflection or refraction does not occur at the interface of each layer, so that there is no variation in sensitivity and uniform sensitivity is maintained.

According to the second aspect of the invention, since the microlens layer and the intermediate film filling the irregularities between the microlens layer and the semiconductor substrate are made of materials having the same refractive index, the incident light at the interface between the two can be treated. Reflection does not occur, deterioration of sensitivity and image deterioration are prevented, and uniform sensitivity is maintained, as in the first aspect of the invention.

In the third aspect of the invention, since the filter film and the microlens layer are integrally formed by using the materials having the same refractive index, the pattern of each layer does not become non-uniform and the sensitivity is deteriorated. Image deterioration and sensitivity variation can be prevented more reliably.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

First, the first embodiment will be described. Figure 1
[FIG. 8] is a sectional view of the solid-state image pickup device in the first embodiment. In FIG. 1, 1 is a semiconductor substrate made of silicon, 2 is a light receiving portion made of a photodiode, and 3 is a light shielding portion made of aluminum.

Next, the structure of the upper portion of the light receiving portion 2, which is a characteristic part of the present invention, will be described.

First, the flattening layer 4 is formed of gelatin resin. Next, a color filter layer 5 made of the same gelatin resin as that used for the flattening layer 4 and dyed in a desired color is formed. Further, the intermediate layer 6 is formed of the same gelatin resin as that used for the flattening layer 4 and the color filter layer 5. Then, the microlens layer 7 is formed of the same gelatin-based resin as that used for the flattening layer 4, the color filter layer 5, and the intermediate layer 6.

The flattening layer 4, the color filter layer 5 and the intermediate layer 6 function as a filter film in the invention of claim 1, and the filter film composed of a multilayer film is made of a material having the same refractive index. . In addition, the flattening layer 4,
The color filter layer 5 and the intermediate layer 6 function as an intermediate film in the invention of claim 2, and the microlens layer 7 and the intermediate film are made of a material having the same refractive index.

The operation of the solid-state image pickup device of the first embodiment constructed as described above will be described below.

In FIG. 1, when light enters the solid-state image pickup device, the microlens layer 7, the intermediate layer 6, the color filter layer 5 and the flattening layer 4 are formed of materials having the same refractive index. , The incident light reaches the light receiving portion 3 without being reflected at the interface of each layer.

Therefore, incident light can be efficiently taken in without causing reflection at the layer interface,
Sensitivity deterioration of the solid-state imaging device is prevented. Further, image deterioration due to the light reflected at the layer interface being re-reflected at another interface is effectively prevented. Further, even if the pattern of each layer becomes non-uniform, since there is no reflection or refraction at the interface of each layer, variations in sensitivity do not occur.

Therefore, sensitivity deterioration in the solid-state image pickup device,
Image deterioration and sensitivity variation can be effectively prevented.

In the first embodiment, gelatin resin is used for the microlens layer 7, the intermediate layer 6, the color filter layer 5 and the flattening layer 4. However, if the same material is used for all layers, the gelatin resin is used. Needless to say, the same effect can be obtained by using a material other than resin.

In the first embodiment, the microlens layer 7, the intermediate layer 6, the color filter layer 5 and the flattening layer 4 are all made of the same material. It suffices if the filter film composed of a multilayer film such as the filter layer 5 is made of a material having the same refractive index, and if it does not have a color filter layer, an intermediate film (flattening layer 4 etc.) and a microlens. The layer 7 may be made of a material having the same refractive index.

Further, even if not all the layers have the same refractive index, if any adjacent layers are made of a material having the same refractive index, the conventional solid-state image pickup device. More effectively, reflection of incident light can be prevented, and the same effect can be obtained.

Next, the second embodiment will be described.

FIG. 2 is a sectional view of the solid-state image pickup device according to the second embodiment. 2, the configuration of the semiconductor substrate 1, the light receiving portion 2 and the light shielding portion 3 is the same as that in the first embodiment.
The configuration is the same as that of.

Here, in the second embodiment, the color filter / microlens layer 21 also serving as both a color filter that transmits only light of an arbitrary wavelength and a microlens that collects incident light uses a gelatin resin. It is integrally formed directly on the light receiving unit 2. That is, the color filter and the microlens are made of materials having the same refractive index, and the flattening layer and the intermediate layer are unnecessary.

The operation of the solid-state image pickup device of the second embodiment constructed as described above will be described below.

In FIG. 2, since the color filter / microlens layer 21 is formed by using one material, when the light enters the solid-state image pickup device, it is reflected in the color filter / microlens layer 21. Light enters without incident. Therefore, incident light can be efficiently taken in, and sensitivity deterioration of the solid-state imaging device can be prevented. Further, since the incident light is not reflected, it is possible to effectively prevent the image deterioration caused by the re-reflected light on the other interface of the incident light entering the other light receiving portion. Further, in this structure, since the color filter / microlens layer 21 is integrally formed, nonuniformity of the pattern of each layer does not occur, and variations in sensitivity and the like can be prevented more reliably.

In the structure having the microlens layer 7, the intermediate layer 6, the color filter layer 5 and the flattening layer 4, even if not all layers have the same refractive index, the invention of claim 1 can be obtained. So-called filter film (flattening layer 4,
A material having the same refractive index as the color filter layer 5 and the intermediate layer 6) and the microlens layer 7 and the intermediate layer 6 (in this case, the intermediate film according to the invention of claim 2 is the intermediate layer 6 only). It may be configured with. For example, in FIG. 3, a gelatin resin is used as the material forming the filter film including the flattening layer 4, the color filter layer 5 and the intermediate layer 6, and only the microlens 7 is formed of another material (for example, phenol resin). The cross section of the solid-state imaging device according to the third example and the state of incident light are shown.

That is, also in the third embodiment, the reflection of incident light can be reduced as compared with the conventional solid-state image pickup device, and sensitivity deterioration, image deterioration, etc. can be prevented as much as possible. .

[0038]

As described above, according to the first aspect of the invention, in the solid-state image pickup device in which the filter film formed of the multilayer film is further formed on the light receiving portion formed on the semiconductor substrate, Is made of a material having the same refractive index, so that when light is incident on the solid-state imaging device, a multilayered structure such as a flattening layer for filling irregularities between the light receiving portion on the semiconductor substrate side and the color filter It is possible to prevent reflection of incident light in the filter film made of a film,
Therefore, it is possible to prevent deterioration of sensitivity, prevent image deterioration due to re-reflected light, and maintain uniform sensitivity.

According to the second aspect of the invention, in the solid-state imaging device in which the microlens layer is formed on the light receiving portion formed on the semiconductor substrate with the intermediate film interposed therebetween, the microlens layer and the intermediate layer are refracted. Since the materials are formed of the same material, the reflection of incident light at the interface between the microlens layer and the intermediate film can be prevented, and the same effect as the invention of claim 1 can be obtained. it can.

According to the third aspect of the present invention, in the solid-state image pickup device in which the microlens layer is formed on the light receiving portion formed on the semiconductor substrate through the filter film, the filter film and the microlens layer have a refractive index. Since they are integrally formed using the same material, in addition to the effect of preventing the reflection of incident light, the uniformity of the pattern of the filter film and the microlens layer reduces the sensitivity, deteriorates the image, and reduces the image quality. It is possible to prevent variations more reliably.

[Brief description of drawings]

FIG. 1 is a sectional view of a solid-state imaging device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a solid-state imaging device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a solid-state imaging device according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a conventional solid-state imaging device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Light receiving part 3 Light shielding part 4 Flattening layer 5 Color filter layer 6 Intermediate layer 7 Micro lens layer 21 Color filter and micro lens layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akito Kidera 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electronics Industrial Co., Ltd. (72) Inventor Hirotatsu Kodama 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electronics Industrial Co., Ltd.

Claims (3)

[Claims] 1. A solid-state imaging device having a semiconductor substrate, a light-receiving portion formed on the semiconductor substrate, and a filter film formed of a multilayer film on the light-receiving portion, wherein the filter film has a refractive index. A solid-state imaging device, wherein the solid-state imaging device is formed of the same material. 2. A solid-state imaging device comprising: a semiconductor substrate; a light receiving portion formed on the semiconductor substrate; and a microlens layer formed on the light receiving portion with an intermediate film interposed therebetween. The intermediate layer is a solid-state imaging device characterized by being formed of a material having the same refractive index. 3. A solid-state imaging device having a semiconductor substrate, a light receiving portion formed on the semiconductor substrate, a filter film formed on the light receiving portion, and a microlens layer formed on the filter film. 2. The solid-state imaging device according to claim 1, wherein the filter film and the microlens layer are integrally formed by using materials having the same refractive index.