JPH0555536A - Image sensor - Google Patents

Abstract

PURPOSE:To improve the sensitivity and provide an easy-to-produce image sensor by condensing the light peripheral to light receiving element section to the light receiving elements. CONSTITUTION:The title device is provided with the light receiving elements 7, 8 and 9 on one surface of a transparent wiring substrate 2. Further, the grooves 11 which have an nearly semicircular cross-section are formed in the side of the position corresponding to the fixing positions of the elements 7, 8 and 9 on one surface of a transparent member, and on the other surface of the transparent member is stucked to the surface of the substrate where light receiving elements are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor for optically reading an image signal of a copying machine or a facsimile.

[0002]

2. Description of the Related Art In a solid-state image pickup device using a silicon wafer, a solid-state image pickup device is restricted because an installation area of a photodiode is restricted by an occupied area of aluminum wirings forming vertical and horizontal scanning circuits. A method is taken to increase the aperture ratio by increasing the ratio of the apparent light receiving area in the whole.

As a method of improving the aperture ratio, Japanese Patent Laid-Open No. 59-59
In Japanese Laid-Open Patent Publication No. 94456/94, a lens forming thin film made of an organic material is deposited on the entire surface of the light receiving portion formed on an image pickup substrate, and a microlens for condensing is formed on each light receiving portion by photolithography. A method is disclosed.

On the other hand, in Japanese Patent Laid-Open No. 59-92567, a lens material layer made of an organic material is deposited on the light-receiving surface of a solid-state image pickup device on which a photodiode and a color filter are formed, and this is formed by a photoresist method. Etching is performed to form a condenser lens above the installation position of the photodiode.

[0005]

According to the above-described method of forming the condenser lens, for example, the solid-state image pickup device has a light receiving area of about 10 × 10 μm ^2, and a hemispherical lens having a film thickness of 2 μm is formed on the light receiving area. If this is done, the apparent aperture ratio can be improved by about 1.5 times, but the one-dimensional 40
In the 0SPI contact-type image sensor, the light receiving area is about 50 × 50 μm ² , which is 2 μm.
When a hemispherical condensing lens is formed with the film thickness of, the film thickness of the lens is thin in proportion to the large light receiving area, so the condensing ratio is inferior and the apparent aperture ratio is improved compared to the former. It is about 10% at most.

Further, in the two-dimensional 400 SPI contact image sensor, the light receiving area is 40 × 40 μm ² , and when a hemispherical lens having a film thickness of, for example, 10 μm or more is formed on this, significant sensitivity is obtained. However, there is a problem that it is generally difficult to uniformly coat a material having a thickness of 10 μm and make the curvature of the lens in the radial direction uniform by a method such as photolithography and to manufacture the lens with good reproducibility. ..

The present invention has been made in view of the above-mentioned problems, and its object is one-dimensional or two-dimensional.
In an image sensor such as a three-dimensional image sensor, the light around the light receiving element portion is focused on the light receiving element to enhance the sensitivity and to provide an image sensor which can be easily manufactured.

[0008]

Therefore, in order to solve the above-mentioned problems, the image sensor according to claim 1 of the present invention is an image sensor having a light receiving element on one surface of a transparent wiring substrate. A groove with an approximately semicircular cross section is provided on the side of one surface corresponding to the installation position of the light receiving element, and the non-installation surface side of the groove of this transparent member is attached to the light receiving element installation surface side of the transparent wiring board. It is designed to be worn.

An image sensor according to a second aspect of the present invention is an image sensor in which a light receiving element is provided on one surface of a transparent wiring substrate, and a color filter substrate is laminated on the upper surface of the light receiving element. On the side of the color filter non-installed side of the device, which has a semi-circular cross section on the side corresponding to the position where the light receiving element is installed, the color filter installation surface side of the color filter substrate is installed on the transparent wiring substrate It is configured by being attached to the surface side.

Further, the image sensor according to claim 3 of the present invention is an image sensor having a light receiving element on one surface of a transparent wiring substrate, wherein the position on the one surface of the transparent member corresponding to the installation position of the light receiving element. The transparent member is provided with a groove having a substantially semicircular cross section having a size exceeding both sides of the corresponding position, and a member having a light refractive index higher than that of the transparent member is provided in the groove. Is attached to the side of the transparent wiring substrate on which the light receiving element is installed.

[0011]

According to the image sensor of claim 1, the light incident on the flat surface of the transparent member is directly received by the light receiving element, while the light incident on the side portion of the light receiving element is refracted by the groove having a substantially semicircular cross section. It is incident on the light receiving element.

Further, in the image sensor of claim 2, incident light on the side of the light receiving element is refracted by a groove having a substantially semicircular cross section provided on the non-installation surface side of the light receiving element, and color separation is performed by a color filter. Then, the light is collected on the light receiving element.

Further, in the image sensor of claim 3, the light incident on the side portion of the light receiving element has a substantially semicircular cross-section having a size from a position corresponding to the installation position of the light receiving element to both side portions of the corresponding position. Incident on the groove, and is further refracted by the high-refractive index member provided in the groove to enter the light receiving element.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on the embodiments shown in the accompanying drawings. In FIG. 1, a groove having a substantially semicircular cross section is provided on the side of the position corresponding to the installation position of the light receiving element.
2 is a plan view of the image sensor shown in FIG. 1. FIG.

FIG. 1 is a cross-sectional view of the two-dimensional image sensor 1 shown in FIG. 2 as seen from the section AA in the direction of the arrow, showing the upper surface of the transparent wiring substrate 2 such as glass in the sub-scanning direction. , Cr (chrome) deposited by the sputtering method is patterned to form three Cr metal electrodes 3, 3,
3 are arranged in parallel, and these are also arranged vertically in the main scanning direction. Photoelectric conversion layers 4, 4, 4 such as amorphous silicon (a-Si) are deposited on the upper surfaces of the Cr metal electrodes 3, 3, 3 by a CVD method, and further, these photoelectric conversion layers 4,
Transparent electrodes 5, 5, 5 made of indium tin oxide or the like are deposited on the upper surfaces of 4, 4 by a sputtering method and patterned to form light receiving elements 7, 8, 9. Then, the transparent electrodes 5, 5, 5 and the upper part, and the transparent wiring substrate 2
A passivation film 6 made of polyimide is coated on the upper surface of the.

Next, when a glass substrate such as Corning 7059 (made by Corning) is used as a transparent plate, C
F ₄ , SF ₆ , or a chlorofluorocarbon-based gas, or a mixture of these gases, is used to detect the light-receiving element 7 on the glass substrate.
Isotropic etching is performed outside the positions corresponding to the installation positions of 8 and 9 in the main scanning direction to form grooves 11 and 1 having a substantially semicircular cross section.
Four 1, 1, 11 are formed.

The formation of the grooves 11, 11, 11, 11 is as follows.
It is also possible to create it by a wet process using an etching solution such as hydrofluoric acid. When an organic material such as polysulfone, polyethersulfone, polyarylate, polyetheramide, polyamideimide, or amorphous polyolefin is used as the transparent plate forming the grooves 11 ..., Injection molding or casting It is also possible to form the transparent plate 10 having the light collecting groove by a method such as a method.

The grooves 11 of the transparent plate 10 formed in this way
.. The non-installation surface side of the light receiving element 7 of the transparent wiring substrate 2,
The image sensor 1 is prepared by facing the installation surface side of 8 and 9 and adhering it to the upper surface of the passivation film 6 with an appropriate transparent adhesive.

The operation of the image sensor 1 described above will be described. When a part of the image light 12 incident from the light incident surface side is incident on the flat surface of the transparent plate 10 located immediately above the light receiving elements 7, 8 and 9, it is directly incident on the light receiving elements 7, 8 and 9. Further, the image light 12 incident on a part of the peripheral surface of the grooves 11, 11, 11, and 11 located outside the position corresponding to the installation position of the light receiving elements 7, 8, and 9 is the light that these grooves have. The light is refracted by the refraction and enters the light receiving elements 7, 8 and 9.
Therefore, the amount of light received by the light receiving elements 7, 8 and 9 is significantly increased.

FIG. 3 shows an example in which the present invention is applied to an image sensor in which a light receiving element is provided on one surface of a transparent wiring substrate and a color filter substrate is laminated on the light receiving element. In the plan view of the embodiment of the present invention shown in FIG. 4, there is shown a cross section of the cutting plane B-B viewed in the arrow direction. Note that reference numerals 2 to 10 in the figure are the same constituent elements as those shown in FIG.

In FIG. 3, the installation positions of the light receiving elements 7, 8 and 9 formed on one surface of the transparent plate 10 which is a color filter substrate by an arbitrary coloring method such as a dispersion coloring method or a dyeing method. R (red), G (green), and B (blue) color filters 13, 14 and 15 having a size exceeding both outsides of the corresponding position from the position are provided. And this transparent plate 1
No. 4 of the color filters 13, 14 and 15 on the non-installation surface side and outside the positions corresponding to the installation positions of the light receiving elements 7, 8 and 9 are four grooves 11, 11, 11 having a substantially semicircular cross section. 1
1 is formed by the above-mentioned isotropic etching or the like. The side of the transparent plate 10 on which the color filters 13, 14 and 15 are installed faces the passivation layer 6 and is attached with a transparent adhesive to form the color image sensor 1.

According to this structure, the image light 12 that has entered the flat surface of the transparent plate 10 has the color filters 13, 14,
The image light of R, G, and B which has been color-separated via 15 is incident on the light receiving elements 7, 8 and 9, and the image light which is incident from both outer sides of the light receiving elements 7, 8 and 9 is the groove 11 ... The light is refracted toward the light receiving element side by the condensing action of, and the color filters 13, 14,
The color is separated into R, G, and B by 15 and condensed on the light receiving elements 7, 8, and 9.

In the embodiment shown in FIGS. 1 and 3,
It is possible to further improve the light collection efficiency by providing the groove 11 not only in the main scanning direction but also in the sub scanning direction.

FIG. 5 shows a cross section of another embodiment in which the present invention is applied to a one-dimensional image sensor. In addition,
Reference numerals 2 to 10 in the figure are the same constituent elements as those described in FIG. 1, and thus detailed description thereof will be omitted. The transparent plate 10 is located on the side of the surface facing the one row of light receiving elements 16 arranged in parallel in the main scanning direction, and has a cross section of a size larger than the corresponding position of the installation position of the light receiving elements 16 and outside the corresponding positions. One semicircular groove 11 is formed by the above-mentioned isotropic etching or the like. Then, the groove 11 is filled with a high refractive index member 17 having a refractive index higher than the optical refractive index of the transparent plate 10 and made of an organic material such as polyimide or an inorganic material. Then, the surface side of the transparent plate 10 on which the groove 11 is provided faces the installation surface side of the light receiving element 16, and is adhered to the surface of the passivation film 6 with an appropriate transparent adhesive.
With this configuration, the image light 12 incident on the outside of the light receiving element 16 via the light incident surface side of the transparent plate 10 is efficiently condensed on the light receiving element 16 by the photorefractive action of the high refractive index member 17.

Even when the transparent plate 10 shown in the embodiment of FIG. 5 has a structure in which the groove-non-installed surface side is attached to the light-receiving element installation surface side, the same effect can be obtained. It is also possible to provide a plurality of the grooves 11 to be applied to a two-dimensional image sensor.

FIG. 6 is a sectional view of a modification of the embodiment shown in FIG. 5 described above. In this example, of the transparent plate 10,
On the surface of the corresponding position on the installation position side of the light receiving elements 7, 8 and 9, three cross-sections each having a size of a semicircle of a size exceeding the corresponding positions of the installation positions of the light receiving elements 7, 8 and 9 to the outside of the corresponding positions Grooves 11, 11, 11 are provided. A color that separates the image light into R, G, and B colors by filling the grooves 11, 11, and 11 with a polyimide or the like in which a pigment is dispersed and having a refractive index higher than that of the transparent plate 10. Filters 18, 19, 2
Form 0. The surface of the transparent plate 10 on which the grooves 11, 11, 11 are provided faces the light receiving elements 7, 8, 9 and is attached.
According to this configuration, the transparent plate 10 to the light receiving elements 7, 8,
The image light 12 incident on the outside of 9 is the color filters 18 and 1 made of polyimide having a high optical refractive index.
The light is separated into R, G, and B by 9, 20 and is refracted and efficiently condensed on the light receiving elements 7, 8, 9.

FIG. 7 shows a modification of the embodiment shown in FIG. 6, and is a cross-sectional view of the section CC taken in the direction of the arrow in the plan view of the embodiment of the color image sensor shown in FIG. It is a figure. Note that reference numerals 2 to 10 in the figure are the same components as those shown in the embodiment of FIG.
The detailed description is omitted.

In FIG. 7, three grooves 11 each having a substantially semicircular cross section and having a size exceeding a position corresponding to the installation position of the light receiving elements 7, 8 and 9 on the transparent plate 10 and outside the corresponding positions.
11, 11 are provided in the main scanning direction by the above-mentioned isotropic etching or the like, and the semi-circular grooves 11, 11, 1 are provided.
1 is filled with polyimide or the like in which a pigment is dispersed and has a higher optical refractive index than that of the transparent plate 10, and image light is colored into R (red), G (green), and B (blue). The color filters 18, 19 and 20 to be separated are formed. The transparent plate 10 thus formed is pasted with a transparent adhesive so that the non-installation surface side of the grooves 11, 11, 11 faces the light receiving elements 7, 8, 9. According to this configuration, the image light 12 incident on the outside of the light receiving elements 7, 8 and 9 from the image light incident surface side of the transparent plate 10.
Are R, G, B by the color filters 18, 19, 20.
The image light 12 is refracted by the polyimide having a high optical refractive index while being color separated into
Is focused on.

In the embodiment described above, the light collecting groove is formed on the transparent plate 10 and then the transparent wiring board 2 is formed.
It is possible to form grooves having an arbitrary size ranging from several microns to several hundreds of microns because it is attached to the. Needless to say, the curvature and size of the groove can be appropriately changed according to the design value of the wiring of the image sensor and the structure of the image sensor.

[0030]

As described above, according to the present invention, in the image sensor having the light receiving element on one surface of the transparent wiring substrate, the light receiving element installation position on one surface of the transparent member as another member corresponds to the light receiving element installation position. Since a groove with a substantially semicircular cross section is provided on the side of the position where the groove is formed, the groove can be formed without any restrictions on the wiring space of the light receiving element installation part, and the cross sectional shape of the groove Since the shape is semicircular, the shape may be created in consideration of the uniformity of the shape only in the circumferential surface direction, and thus, the shape can be easily created. Since the light incident on the side of the light receiving element can be condensed on the light receiving element, the light collection rate on the light receiving element becomes large, and the sensitivity of the image sensor can be significantly increased. Moreover, even if such a configuration is applied to a color easy sensor, the same effect can be obtained.

Further, according to the present invention, one surface of the transparent member is provided with a groove having a substantially semicircular cross section having a size exceeding a position corresponding to the light receiving element installation position and both sides of the corresponding position, Since a member having a light refractive index higher than that of the transparent member is provided in this groove, it is possible to collect the light incident from the side portion where the light receiving element is installed at the light receiving element. ..

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of an image sensor of the present invention.

FIG. 2 is a plan view of the embodiment shown in FIG.

FIG. 3 is a sectional view of an embodiment in which the present invention is applied to a color image sensor.

FIG. 4 is a plan view of the embodiment shown in FIG.

FIG. 5 is a sectional view of an embodiment in which the present invention is applied to a one-dimensional image sensor.

6 is a sectional view of a modification of the embodiment shown in FIG.

7 is a cross-sectional view of a color image sensor which is a modification of the embodiment shown in FIG.

FIG. 8 is a plan view of the modified example shown in FIG. 7.

[Explanation of reference numerals] 1 image sensor, 2 transparent wiring substrate, 3 metal electrode, 4 photoelectric conversion layer such as amorphous silicon, 5
Transparent electrode, 6 passivation film, 7, 8, 9 and 1
6 light receiving element, 10 transparent plate, 11 grooves having a substantially semicircular cross section, 12 image light, 17 a member having a high optical refractive index,
13 to 15 and 18 to 20 color filters.

Claims (3)

[Claims] 1. An image sensor having a light receiving element on one surface of a transparent wiring substrate, comprising:
A groove having a substantially semicircular cross section is provided on a side portion of a position corresponding to the installation position of the light receiving element, and the non-installation surface side of the groove of the transparent member is attached to the light receiving element installation surface side of the transparent wiring board. An image sensor characterized in that 2. An image sensor comprising a light receiving element on one surface of a transparent wiring substrate, and a color filter substrate laminated on an upper surface of the light receiving element, wherein the color filter substrate is provided with a color filter non-installation surface side. A groove having a substantially semicircular cross section is provided on a side portion corresponding to the installation position of the light receiving element, and the color filter installation surface side of the color filter substrate is attached to the light receiving element installation surface side of the transparent wiring substrate. An image sensor characterized in that 3. An image sensor having a light receiving element on one surface of a transparent wiring substrate, wherein one surface of the transparent member is
A groove having a substantially semicircular cross-section having a size exceeding the positions corresponding to the installation position of the light receiving element and beyond both sides of the corresponding position is provided, and the optical refractive index higher than that of the transparent member is provided in the groove. An image sensor, comprising: a member having: and the transparent member being attached to a light receiving element installation surface side of a transparent wiring substrate.