JPH07226884A - Solid-state imaging device - Google Patents

Abstract

(57) [Summary] [Object] To obtain a solid-state imaging device capable of preventing an abnormality in image output at a connecting portion between solid-state imaging devices without lowering mechanical strength. [Structure] Concavities and convexities are formed on the entire surface of each of the end faces 1b, 2b on the side where the first and second solid-state imaging devices 1, 2 are attached.

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 plurality of solid-state image pickup devices for picking up infrared rays are juxtaposed, and in particular, an abnormal image output which occurs at a connecting portion between the solid-state image pickup devices. It relates to an improved structure.

[0002]

2. Description of the Related Art A solid-state image pickup device in which a photoelectric conversion element array and a mechanism for reading out electric signals are integrated on the same semiconductor substrate is already used in a video camera or the like in the visible region. On the other hand, the development of solid-state image pickup devices in the infrared region is also progressing, and in particular, the infrared solid-state image pickup device using a silicon Schottky barrier diode as a photoelectric conversion part has a resolution equivalent to that of the visible solid-state image pickup device. .

Recently, there is a demand for a solid-state image pickup device having a better resolution. This requirement can be met by further miniaturizing the pixels in the visible range solid-state imaging device, but considering the diffraction limit because the infrared solid-state imaging device has a long wavelength of infrared light, There is a limit. Therefore, in the infrared solid-state imaging device, if the number of pixels is increased, the device becomes large in area, and the yield is reduced due to the increase in chip size. Further, when a pattern is formed using a reduction projection type exposure apparatus, there is a limit to the transferable area, and therefore the chip size cannot be increased. Therefore, the configuration shown in FIGS. 5 and 6 can be considered as a configuration for increasing the resolution of the infrared solid-state imaging device.

FIG. 5 is a plan view showing the structure of a conventional solid-state image pickup device of this type, and FIG. 6 is a cross-sectional view showing a cross section taken along line VI-VI in FIG. 1, 2 and 3 are, for example, the first, second and third Schottky via diodes on a Si substrate.
The first, second, and third solid-state imaging devices in which the photoelectric conversion array units 4, 5, 6 and the means for reading out the electric signals thereof are monolithically formed. Reference numeral 7 denotes infrared light incident on each of the solid-state image pickup devices 1, 2 and 3, and 8 indicates end face 1 of each of the solid-state image pickup devices 1 and 2.
a is a stray light component of the infrared light 7 that occurs when the infrared light 7 is reflected by a and 2a.

The solid-state image pickup devices 1, 2 and 3 are arranged side by side so that the gap between the devices is very small. Therefore, the solid-state image pickup device including the solid-state image pickup elements 1, 2, and 3 effectively includes three photoelectric conversion array units 4,
As a result, the image pickup area is three times as large as that of the case where only one solid-state image pickup device 1 is used, and the resolution can be tripled.

If the pixel pitch of each solid-state image pickup device 1, 2, 3 is d ₀ , the photoelectric conversion array units 4 and 5, and
If the solid-state image pickup devices 1, 2 and 3 are arranged so that the distance d between the centers of the pixels at the ends of 5 and 6 is equal to d ₀ , the solid-state image pickup devices 1 and 2 and the solid-state image pickup devices 2 and 3 can be arranged. The photoelectric conversion array units 4, 5, and 6 are continuously connected. Therefore, an image can be picked up in a large area formed by the photoelectric conversion array sections 4, 5, and 6, and an image having no image loss at the joint portion between the solid-state image pickup elements 1, 2, and 3 can be obtained.

Next, the operation of the conventional solid-state image pickup device configured as described above will be described. Each solid-state image sensor 1,
The infrared light 7 incident on the rays 2 and 3 is transmitted through the transparent Si substrate and is incident thereon, and is detected by each of the photoelectric conversion array units 4, 5, and 6.

[0008]

The conventional solid-state image pickup device is configured as described above, and as shown in FIG. 6, the infrared light 7 is totally reflected by the end faces 1a and 2a of the solid-state image pickup devices 1 and 2 which face each other. As a result, stray light component 8 is generated and is incident on a pixel different from the pixel to which it should be originally incident. Therefore, an abnormality occurs in the image output of the connecting portion between the solid-state imaging devices 1, 2, and 3. A means for reducing the stray light component 8 by thinning the Si substrate is also conceivable, but the solid-state imaging devices 1, 2, 3
However, there is a problem that it is difficult to carry out because of the decrease in mechanical strength.

The present invention has been made in order to solve the above-mentioned problems, and solid-state imaging capable of preventing abnormality in image output at a connecting portion between solid-state image pickup devices without lowering mechanical strength. The purpose is to obtain the device.

[0010]

A solid-state image pickup device according to a first aspect of the present invention is such that solid-state image pickup elements are provided with concavities and convexities on opposite end faces thereof.

In the solid-state image pickup device according to the second aspect of the present invention, a light absorption layer is formed on the end faces of the solid-state image pickup elements facing each other.

In the solid-state image pickup device according to the third aspect of the present invention, a light absorption layer is formed on the entire end faces of the solid-state image pickup elements facing each other.

Further, in the solid-state image pickup device according to a fourth aspect of the present invention, a plurality of light absorption layers each having a surface in a direction perpendicular to the end faces are formed at desired intervals on opposite end faces of the solid-state image pickup elements. It is a thing.

[0014]

According to the first aspect of the present invention, the irregularities formed on the end faces of the solid-state image pickup devices facing each other scatter the stray light component of the infrared light incident on the end faces of the solid-state image pickup device.

In the second aspect of the present invention, the light absorption layer formed on the end faces of the solid-state image pickup elements facing each other absorbs infrared light incident on the end portions of the solid-state image pickup elements.

In the third aspect of the present invention, the light absorbing layer formed on the entire end faces of the solid-state image pickup elements facing each other absorbs infrared light incident on the end portions of the solid-state image pickup elements.

Further, according to claim 4 of the present invention, the plurality of light absorption layers which are formed at desired intervals on the opposing end faces of the solid-state image pickup devices and have the faces in the direction perpendicular to the end faces are the solid-state image pickup devices. Infrared light incident on the edge of is received at an angle close to vertical and efficiently absorbed.

[0018]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. 1 is a plan view showing the configuration of a solid-state imaging device according to Embodiment 1 of the present invention, and FIG. 2 is a line II-II in FIG.
It is sectional drawing which shows the cross section along. In the figure, the same parts as those in the conventional case are designated by the same reference numerals, and the description thereof will be omitted. 1
Reference numerals b and 2b denote end surfaces of the Si substrate 10 that the solid-state image pickup devices 1 and 2 face each other, and the entire surface is formed in a concavo-convex shape.

Next, the operation of the solid-state image pickup device of the first embodiment constructed as described above will be described. As in the conventional case, the infrared light 7 incident on each of the solid-state image pickup devices 1, 2 and 3
Is transmitted through the transparent Si substrate 10 from the surface opposite to the surface on which the photoelectric conversion array sections 4, 5 and 6 are formed, and is incident thereon, and is detected by the photoelectric conversion array sections 4, 5, and 6. This time,
As shown in FIG. 2, the end faces 1 of the substrates of the solid-state imaging devices 1 and 2
Infrared light 7 entering b and 2b is irregularly reflected because the end faces 1b and 2b are uneven, and the stray light component 8 is dispersed and loses energy.

As described above, according to the first embodiment, the end surface 1
The stray light component 8 is dispersed by the unevenness formed in b and 2b and loses energy so that it does not reach the photoelectric conversion array units 4 and 5, so that the photoelectric conversion array units 4 and 5 should actually receive light. Since only light can be received, it is possible to reduce abnormalities in the image output at the connecting portion between the solid-state image pickup devices 1 and 2. Although only the connecting portion between the first and second solid-state imaging devices 1 and 2 is described here, it goes without saying that the connecting portion between the second and third solid-state imaging devices 2 and 3 is also shown. The same can be said.

Example 2. FIG. 3 is a cross-sectional view showing details of the configuration between the solid-state imaging devices of the solid-state imaging device according to the second embodiment. In the figure, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the figure, 9 is a light absorption layer formed on the entire end faces 1c, 2c of the Si substrates 10 facing each other between the solid-state imaging devices 1, 2.

The light absorption layer 9 preferably has a refractive index close to that of the Si substrate 10 in order to prevent total reflection at the end portion. For example, impurities such as boron and phosphorus are ion-implanted into the Si substrate 10. A high-concentration region of 10 ²⁰ cm ^-3 or more is formed to form the light absorption layer 9, or an amorphous silicon film in which impurities such as boron are highly-concentrated to 10 ²⁰ cm ^-3 or more is formed on the Si substrate. The light absorption layer 9 may be deposited.

Next, a second embodiment constructed as described above
The operation of the solid-state imaging device will be described. Example 1 above
Infrared light 7 incident on each solid-state image sensor 1, 2 is S
The light passes through the i-substrate 10 and is detected by the photoelectric conversion array units 4 and 5. At this time, the infrared light 7 incident on the ends of the solid-state image pickup devices 1 and 2 is absorbed by the light absorption layer 9 formed on the end faces 1c and 2c.

As described above, according to the second embodiment, the end face 1c,
The infrared light 7 incident on the end portion is absorbed by the light absorption layer 9 formed in 2c and no stray light component is generated, so that each photoelectric conversion array unit 4 and 5 can receive only the light that should be actually received. It is possible to prevent abnormalities in the image output at the connecting portion between the solid-state image pickup devices 1 and 2.

Example 3. FIG. 4 is a sectional view showing the details of the configuration between the solid-state image pickup elements of the solid-state image pickup device according to the third embodiment of the present invention. In the figure, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 11 denotes a light absorption layer which is embedded in grooves 12 formed at desired intervals in a direction perpendicular to the end faces 1d and 2d of the Si substrates 10 facing each other between the solid-state image pickup devices 1 and 2 in the same manner as in the second embodiment. Is. The depth of the groove 12 is set to a position where it is not blocked by the vertically projected cross-sectional area of each photoelectric conversion array section 4 and 5, and the pitch of the groove 12 is such that all incident infrared light 7 is incident on the end faces 1d and 2d. It is set not to reach.

Next, Example 3 configured as described above
The operation of the solid-state imaging device will be described. Example 1 above
Infrared light 7 incident on each solid-state image sensor 1, 2 is S
The light passes through the i-substrate 10 and is detected by the photoelectric conversion array units 4 and 5. At this time, since the infrared light 7 incident on the ends of the solid-state imaging devices 1 and 2 is incident on the surface of the light absorption layer 11 formed in the vertical direction of the end faces 1d and 2d at an angle close to vertical,
It is efficiently absorbed by the light absorption layer 11.

As described above, according to the third embodiment, the infrared light 7
Is incident on and absorbed by the light absorption layer 11 at an angle nearly perpendicular to the light absorption layer 11, the same effect as in each of the above-described embodiments can be obtained, and the refractive index of the light absorption layer 11 is equal to that of the Si substrate 10. Since the infrared absorption 7 is sufficiently absorbed even if it is slightly different, the light absorption layer 11 may be any material as long as it absorbs the infrared absorption 7.

Example 4. In each of the above embodiments, three solid-state image pickup devices 1, 2 and 3 are arranged side by side in the lateral direction, but the present invention is not limited to this, and a plurality of solid-state image pickup devices may be arranged side by side in both the vertical and horizontal directions. It goes without saying that the same effect can be obtained even when applied to the solid-state imaging device described above.

[0029]

As described above, according to claim 1 of the present invention, since the concavities and convexities are formed on the opposed end faces of the solid-state image pickup devices, the image output between the solid-state image pickup devices can be performed without lowering the mechanical strength. There is an effect that it is possible to obtain a solid-state imaging device that prevents the above abnormality.

Further, according to the second aspect of the present invention, since the light absorption layer is formed on the end faces of the solid-state image pickup elements which face each other, the abnormality in the image output between the solid-state image pickup elements can be prevented without lowering the mechanical strength. There is an effect that it is possible to obtain a solid-state image pickup device that prevents it.

Further, according to the third aspect of the present invention, since the light absorption layer is formed on the entire end faces of the solid-state image pickup elements facing each other, the image output between the solid-state image pickup elements can be performed without lowering the mechanical strength. There is an effect that a solid-state imaging device that prevents an abnormality can be obtained.

Further, according to the fourth aspect of the present invention, since the solid-state image pickup elements are provided with a plurality of light absorption layers at desired intervals, each having a surface in the direction perpendicular to the opposite end surfaces, The solid-state imaging device may not only prevent abnormalities in image output between the solid-state imaging devices without lowering mechanical strength, but may use any light absorption layer as long as it can absorb infrared light. There is an effect that can be obtained.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a section taken along line II-II in FIG.

FIG. 3 is a cross-sectional view showing details of a configuration between solid-state image pickup elements of a solid-state image pickup device according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing details between solid-state image pickup elements of a solid-state image pickup device in Embodiment 3 of the present invention.

FIG. 5 is a plan view showing a configuration of a conventional solid-state imaging device.

6 is a cross-sectional view showing a cross section taken along line VI-VI in FIG.

[Explanation of symbols]

 1 1st solid-state image sensor 2 2nd solid-state image sensor 3 3rd solid-state image sensor 4 1st photoelectric conversion array part 5 2nd photoelectric conversion array part 6 3rd photoelectric conversion array part 7 Infrared light 8 Stray light component 9, 11 Light absorption layer 10 Si substrate 12 Groove

Claims (4)

[Claims] 1. A solid-state image pickup device comprising a plurality of solid-state image pickup devices arranged side by side, the solid-state image pickup device having a photoelectric conversion unit provided on one surface of a semiconductor substrate and detecting infrared rays incident from the other surface to convert the infrared light into an electric signal. A solid-state image pickup device, wherein irregularities are formed on end faces of image pickup devices which face each other. 2. A solid-state image pickup device in which a plurality of solid-state image pickup devices, each of which is provided on one surface of a semiconductor substrate and has a photoelectric conversion unit for detecting infrared rays incident from the other surface and converting the infrared rays into an electric signal, are arranged side by side. A solid-state image pickup device, wherein a light absorption layer is formed on end faces of image pickup devices facing each other. 3. The solid-state imaging device according to claim 2, wherein the light absorption layer is formed on the entire end surface of the solid-state imaging device. 4. The solid-state imaging device according to claim 2, wherein a plurality of light absorption layers each having a surface in a direction perpendicular to the end surface of the solid-state imaging device are formed at desired intervals.