JPH05326901A - Solid-state image sensing device and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the dispersion of light receiving sensitivity and the occurrence of white flaws caused by the light in a far ultraviolet ray region. CONSTITUTION:A layer 15 for absorbing invisible light is provided on a color filter part 3 corresponding to a light receiving part 2 on a solid-state image sensing device substrate 1. On the layer 15, a micro-lens layer 16 having the uniform shape is formed. In this constitution, incident light is converged with the micro-lens layer 16. Invisible light of the wavelength of less than 400nm is absorbed in the absorbing layer 15. Therefore, only the light in the intended visible region is incident on the light receiving part 2.

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 having a color filter having a microlens and a method of manufacturing the same.

[0002]

2. Description of the Related Art As a method for colorizing a solid-state image pickup device, a color filter is directly formed on a substrate on which the solid-state image pickup device is formed, and incident light is condensed on each light-receiving section to obtain a solid-state image pickup device. A method of forming a microlens on the color filter in order to increase the sensitivity has become the mainstream.

A conventional solid-state image pickup device and a method of manufacturing the same will be described with reference to the drawings. FIG. 8 is a partially enlarged sectional view showing the structure of a conventional solid-state imaging device. 9 to 13 are partial enlarged cross-sectional views showing a method of manufacturing the conventional solid-state imaging device shown in FIG. 8 in the order of steps.

In these figures, 1 is a solid-state image pickup device substrate. Reference numeral 2 is a light receiving portion that receives incident light. Reference numeral 3 is a complementary color system such as magenta (Mg), yellow (Ye), cyan (Cy), or a color filter portion of red (R), green (G) and blue (B). A microlens layer 4 has a semicircular cross section. Reference numeral 5 is an ultraviolet-sensitive material layer for forming microlenses. Reference numeral 6 is an ultraviolet-sensitive material layer pattern. Reference numeral 7 is a transparent ultraviolet light-sensitive material layer pattern.

First, the structure of a conventional solid-state image pickup device will be described with reference to FIG. A desired color filter portion 3 is formed on the substrate 1 of the solid-state imaging device so as to correspond to each light receiving portion 2, and the surface of the color filter portion 3 is flattened with a transparent resin or the like (not shown). ing. Then, a microlens layer 4 having a semicircular cross section is formed on the flattened color filter portion 3 and has a structure in which incident light is focused on the light receiving portion 2. With the structure as described above, the solid-state imaging device including the color filter having the microlens layer 4 is realized.

Next, the operation of the conventional solid-state image pickup device will be described with reference to FIG. Light incident on the uppermost microlens layer 5 is focused by the microlens layer 5. Then, the focused light passes through the color filter unit 3 and undergoes color separation. Each color-separated light enters the light receiving unit 2 and is processed as a color signal to realize a solid-state imaging device that provides a color image.

Next, a conventional method for manufacturing a solid-state image pickup device will be described in order of steps with reference to FIGS.

First, FIG. 9 shows a state in which a color filter portion 3 corresponding to each light receiving portion 2 is formed on a solid-state image pickup device substrate 1 and the surface thereof is flattened by a transparent material or the like (not shown). ing.

FIG. 10 shows a state in which the ultraviolet photosensitive material layer 5 is formed by applying a positive ultraviolet photosensitive resin, which is a material for forming the microlens layer 4, for example.

Subsequently, the ultraviolet-sensitive material layer 5 formed by coating is subjected to patterning exposure with ultraviolet light having a wavelength of 436 nm, development and rinsing treatments are carried out, and the ultraviolet-sensitive material layer pattern 6 is formed. It is FIG.

Next, FIG. 12 shows that the ultraviolet-sensitive material layer pattern 6 is entirely irradiated with light having a wavelength in the ultraviolet region of 400 nm or more to improve the transmittance of the ultraviolet-sensitive material layer pattern 6 in the visible light region. Then, the transparent ultraviolet light-sensitive material layer pattern 7 is formed. The transmittance is improved to 90% or more.

Next, in FIG. 13, the transparent UV-sensitive material layer pattern 7 is heated at about 150 ° C. to melt and
This is a state in which the microlens layer 4 is formed by being fluidized. Conventionally, the solid-state imaging device including the color filter having the microlens layer 4 has been realized by the above method.

[0013]

However, in the above-mentioned conventional structure, there is no problem when the incident light has a desired wavelength in the visible light region, but light having a wavelength in the invisible light region which is not necessary in natural light. Is always included, and uneven sensitivity occurs due to the incidence of light having a wavelength in the invisible light region,
There are issues such as white spot induction.

A description will be given below with reference to the drawings. 14
FIG. 6 is a partially enlarged cross-sectional view showing a mechanism of the problem of the conventional solid-state imaging device. In FIG. 14, 1 is a solid-state imaging device substrate. 2 is a light receiving part. 4 is a microlens layer. Reference numeral 8 is a magenta layer in the color filter section. Reference numeral 9 is a yellow layer in the color filter section. Reference numeral 10 is a cyan layer in the color filter section. Reference numeral 11 is light passing through the magenta layer. Reference numeral 12 is light passing through the yellow layer. Reference numeral 13 is light passing through the cyan layer. 14 is a charge transfer unit.

For example, the structure of the color filter section 3 is
In the case of each color layer of the magenta layer 8, the yellow layer 9 and the cyan layer 10, the yellow layer 9 is the only layer that can absorb the problematic invisible light region light to some extent, and the other color layers absorb it. There is almost no ability. The yellow layer 9 can absorb light in a wavelength range around 350 to 450 nm. Therefore, when the incident light including the invisible light region light is focused by the microlens layer 4 and passes through the color filter unit 3, the light that passes through the magenta layer 8 and the cyan layer 10, that is, the magenta layer passing light 11 and the cyan layer passing Light 13
The respective lights of 1) include light in the invisible light region, and the yellow layer passing light 12 has a small ratio including the light in the invisible light region. Therefore, the invisible light region light is directly incident on the light receiving portion 2 below the magenta layer 8 and the cyan layer 10 without color separation, and the incident amount of the invisible light region light is incident on the light receiving portion 2 below the yellow layer 9. Is few. This causes variations in light receiving sensitivity.

Further, when the far ultraviolet ray having a wavelength of 300 nm or less is incident on the light receiving portion 2 as the invisible ray region light which has not been color-separated, there is a possibility that a defect called white spot may occur in image characteristics. This is because when the far-ultraviolet light is received by the light receiving unit 2 and converted into an electric signal, it is not efficiently transferred by the charge transfer unit 14 and remains in the solid-state imaging device, which is considered to be one of the causes of white spots. There is. The phenomenon in which the remaining signal becomes a white spot and appears in the image is called white spot.

The light in the visible light range referred to in the present invention is
It is light having a wavelength of 400 to 700 nm. Light in the invisible light region is light having a wavelength of less than 400 nm, and light having a wavelength of more than 700 nm is excluded.

Further, in the manufacturing method, the microlens layer 4 is formed by directly exposing the ultraviolet-sensitive material layer 5 on the color filter portion 3 with light having a wavelength of 436 nm to form a pattern. However, halation occurs due to exposure reflected light from the underlying charge transfer portion and the like, and the shape of the formed UV-sensitive material layer pattern 6 is not uniform, and as a result, a microlens layer 4 having an uneven shape is formed.
If the shape of the microlens layer 4 is non-uniform, the light-collecting rate of incident light will also be non-uniform, and the light-receiving sensitivity will vary.
Poor sensitivity due to image characteristics.

[0019]

The present invention has the following constitution in order to solve the above-mentioned conventional problems. That is, a structure having a light receiving portion, a color filter portion, which are sequentially formed on the solid-state imaging device substrate, a non-visible light region light absorbing layer on the color filter portion, and a microlens layer at a position corresponding to the light receiving portion. Become.

Further, in the manufacturing method, a step of forming a non-visible light region light absorbing layer on the color filter formed on the solid-state image pickup device substrate, and a photosensitive material layer on the non-visible light region light absorbing layer. A step of forming, a step of selectively exposing the photosensitive material layer with light having a wavelength in the invisible light region to form a photosensitive material layer pattern, and a step of exposing the entire surface of the photosensitive material layer pattern, And a step of forming a microlens layer by heating the photosensitive material layer pattern after the whole surface exposure.

[0021]

Even when light in the invisible light region exists in the incident light, the invisible light region light absorption layer provided under the microlens layer absorbs the invisible light region light. As a result, since the light that enters the color filter unit is only the light in the visible light region that is required, the light that has been efficiently color-separated enters each light receiving unit. Therefore, variations in light receiving sensitivity due to incidence of light in the invisible light region, defects such as white spots, etc. are eliminated.

In the manufacturing method, when the microlens layer is formed, an invisible light region light absorbing layer is provided as a lower layer, and then the photosensitive material layer is exposed to light in the invisible light region to form a pattern. ing. Therefore, reflected light at the time of exposure can be absorbed, halation can be prevented, patterning property can be improved, and a microlens layer having a uniform shape can be formed.

[0023]

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

FIG. 1 is a partially enlarged sectional view showing the structure of a solid-state image pickup device according to an embodiment of the present invention. 2 to 7 are partial enlarged cross-sectional views showing a method of manufacturing the solid-state imaging device according to the embodiment of the present invention in the order of steps. 1 and 2 to 7
In the figure, 1 is a solid-state imaging device substrate. 2 is a light receiving part. 3 is a color filter section. Reference numeral 15 is a non-visible light region light absorption layer. 16 is a microlens layer. 17 is an exposure wavelength of 365 nm in the invisible light region
It is a positive type photosensitive material layer which is exposed to light of wavelength. 1
Reference numeral 8 is a photosensitive material layer pattern. Reference numeral 19 denotes a transparent photosensitive material layer pattern which is improved in transmittance in the visible light region by irradiation with ultraviolet rays.

First, the structure of the solid-state image pickup device according to the present invention will be described with reference to FIG. A color filter portion 3 for color-separating incident light is formed at a position corresponding to each light receiving portion 2 on the solid-state imaging device substrate 1. The color filter unit 3 may be composed of, for example, magenta (Mg), yellow (Ye) and cyan (Cy) complementary color filter layers or red (R), green (G) and blue (B) filter layers. is there. A non-visible light region light absorption layer 15 is formed on the color filter portion 3. A microlens layer 16 that focuses incident light and guides it to the light receiving unit 2 is uniformly formed on the non-visible light region light absorption layer 15.

Next, the operation will be described. Light incident on the microlens layer 16 which is the uppermost layer is focused and enters the light receiving unit 2. In the process, since the incident light includes light in the invisible light region, the light in the invisible light region is absorbed by the invisible light region light absorption layer 15 which is the lower layer of the microlens layer 16. Then, only the desired light in the visible light region passes through the color filter unit 3 and undergoes color separation.
Each color-separated light enters the light receiving unit 2 and is processed as a color signal to realize a solid-state imaging device that provides a color image.

With the configuration and operation as described above, the solid-state image pickup device according to this embodiment has the non-visible light region light absorption layer 15
Absorbs light in the invisible light region. Therefore, it is possible to realize a solid-state imaging device which receives only light in a desired visible light region and provides a color image without variations in light-receiving sensitivity and without image defects such as white spots.

2 to 7, a method of manufacturing the solid-state image pickup device according to the embodiment of the present invention will be described in the order of steps.

First, FIG. 2 shows a state in which a color filter portion 3 corresponding to each light receiving portion 2 is formed on a solid-state image pickup device substrate 1, and the surface thereof is flattened by a transparent resin or the like.

FIG. 3 shows a state in which the non-visible light region light absorbing layer 15 having a desired thickness is applied and formed on the flattened color filter portion 3 and cured and baked.

Next, as shown in FIG. 4, a positive type photosensitive resin, which is a material for forming the microlens layer 16, is applied by a desired thickness, and the temperature is about 100.degree. It is in a state where the photosensitive material layer 17 is formed by baking.

Next, as shown in FIG. 5, the photosensitive material layer 17 formed by coating is subjected to patterning exposure with light having a wavelength of 365 nm in the invisible light region generally called i-line as an exposure wavelength, and development / rinse processing is performed. It is a state in which the photosensitive material layer pattern 18 has been formed. Here, since the non-visible light region light absorption layer 15 is present in the lower layer to prevent halation, the patterning property is improved.

Next, FIG. 6 shows the photosensitive material layer pattern 18
On the other hand, the entire surface is irradiated with light having a wavelength in the ultraviolet region to improve the transmittance of the photosensitive material layer pattern 18 in the visible light region to form the transparent photosensitive material layer pattern 19. The transmittance is improved to 90% or more.

Next, in FIG. 7, the transparent photosensitive material layer pattern 19 is heated at about 150 to 200 ° C. to melt and
This is a state in which the microlens layer 16 is formed by being fluidized.
The shape is a semi-circular shape in the cross-sectional direction or a separated and independent dot shape having a shape close to a semi-circular shape. Further, by increasing the temperature accuracy of the heat treatment, the microlens layer 16 having a uniform shape can be formed. The solid-state imaging device including the color filter having the microlens layer 16 can be realized by the above method.

As materials for the invisible light region light absorption layer 15, PMMA (polymethylmethacrylate) and P are used.
Examples thereof include a copolymer with GMA (polyglycidyl methacrylate) to which an i-ray (365 nm wavelength light) absorbing dye or the like is bound. The transmittance in the visible light region is 10
It should be close to 0% and has excellent thermosetting property. As for the thickness, it is necessary to avoid applying an extremely thick coating because the distance from the light receiving portion 2 to the formed microlens 16 becomes long, which leads to deterioration of characteristics such as deterioration of light receiving sensitivity.

Examples of the material of the photosensitive material layer 17 for forming the microlens layer 16 include a phenol-type positive resist having naphthoquinonediazide as a photosensitive group, and the lower non-visible light absorption layer 15 is used. And adhesion,
It suffices that they are compatible with each other and that they can be selectively exposed with light having a wavelength of 365 nm to form a fine pattern. And the transmittance of visible light is 90
Anything that can be increased to more than 10% may be used. This is to prevent the deterioration of the light receiving sensitivity due to the decrease of the transmittance. Further, any material may be used as long as it is a material having excellent reliability such as chemical resistance because the shape change due to thermoplasticity and the shape fixing due to thermosetting proceed substantially at the same time by heat treatment and the shape is determined by the progress difference between the two.

According to the above-described manufacturing method, a non-visible light region light absorbing layer 15 that absorbs light having a wavelength of 365 nm is provided as a lower layer, and then a photosensitive material layer 17 that is sensitive to light having a wavelength of 365 nm is used. To form the microlens layer 16. Therefore, the microlens layer 16 having an excellent patterning property and a uniform shape can be formed.

The solid-state image pickup device and the method for manufacturing the same according to the present embodiment are for the case of interposing a color filter, but it goes without saying that the same effect can be obtained in the case of interposing only a black light shielding layer other than the color filter. ..

[0039]

As described above, in the solid-state image pickup device according to the present invention, by providing the non-visible light region light absorption layer on the color filter and below the microlens layer, the non-visible light of less than 400 nm of the incident light is absorbed. Only light in the visible light range can be absorbed. Therefore, since the light receiving section receives only the light in the target visible light region, there is no variation in the light receiving sensitivity. In addition, the occurrence of image defects such as white spots due to light having a wavelength near 300 nm, which is an invisible light region, is also eliminated. Therefore, a solid-state imaging device that provides an excellent color image is realized.

Further, in the manufacturing method, a material in the invisible light region as a photosensitive wavelength is used as the patterning material, and a non-visible light region light absorbing layer that absorbs the photosensitive wavelength of the material is formed below the material layer. Then, patterning is performed by selective exposure using a mask. Therefore, halation due to reflection from the base during exposure can be prevented, and the patterning property can be improved. As a result, a microlens layer having a uniform shape can be formed.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view showing the structure of a solid-state imaging device according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a first step of a method for manufacturing a solid-state imaging device according to an embodiment of the present invention.

FIG. 3 is a partially enlarged cross-sectional view showing a second step of the method for manufacturing the solid-state imaging device according to the embodiment of the present invention.

FIG. 4 is a partially enlarged sectional view showing a third step of the method for manufacturing the solid-state imaging device according to the embodiment of the present invention.

FIG. 5 is a partially enlarged sectional view showing a fourth step of the method for manufacturing the solid-state imaging device according to the embodiment of the present invention.

FIG. 6 is a partially enlarged sectional view showing a fifth step of the method for manufacturing the solid-state imaging device according to the embodiment of the present invention.

FIG. 7 is a partially enlarged cross-sectional view showing a sixth step of the method for manufacturing the solid-state imaging device according to the embodiment of the present invention.

FIG. 8 is a partially enlarged cross-sectional view showing the structure of a solid-state imaging device in a conventional example.

FIG. 9 is a first method of manufacturing a solid-state imaging device in a conventional example.
Partially enlarged sectional view showing the process

FIG. 10 is a partially enlarged cross-sectional view showing a second step of the method for manufacturing the solid-state imaging device in the conventional example.

FIG. 11 is a partially enlarged cross-sectional view showing a third step of the method for manufacturing the solid-state imaging device in the conventional example.

FIG. 12 is a partially enlarged cross-sectional view showing a fourth step of the method for manufacturing the solid-state imaging device in the conventional example.

FIG. 13 is a partially enlarged cross-sectional view showing a fifth step of the method for manufacturing the solid-state imaging device in the conventional example.

FIG. 14 is a partially enlarged cross-sectional view showing the mechanism of the problem of the conventional solid-state imaging device.

[Explanation of symbols]

 1 Solid-State Imaging Device Substrate 2 Light Receiving Section 3 Color Filter Section 4 Microlens Layer 5 Ultraviolet Sensitive Material Layer 6 Ultraviolet Sensitive Material Layer Pattern 7 Clarified Ultraviolet Sensitive Material Layer Pattern 8 Magenta Layer 9 Yellow Layer 10 Cyan Layer 11 Magenta Layer passing light 12 Yellow layer passing light 13 Cyan layer passing light 14 Charge transfer part 15 Invisible light region light absorption layer 16 Microlens layer 17 Photosensitive material layer 18 Photosensitive material layer pattern 19 Transparentized photosensitive material layer pattern

Claims (2)

[Claims] 1. A light receiving part, a color filter part, which are sequentially formed on a solid-state image pickup device substrate, a non-visible light region light absorbing layer on the color filter part, and a microlens layer at a position corresponding to the light receiving part. A solid-state imaging device comprising: 2. A step of forming a non-visible light region light absorbing layer on a color filter formed on a solid-state image pickup device substrate, and a step of forming a photosensitive material layer on the non-visible light region light absorbing layer. A step of forming a photosensitive material layer pattern by selectively exposing the photosensitive material layer with light in a non-visible light region; a step of exposing the photosensitive material layer pattern over the entire surface; And a step of forming a microlens layer by heat-treating the conductive material layer pattern.