JPH0667114A - Solid-state image pickup element - Google Patents

Abstract

PURPOSE:To provide the solid-state image pickup element with which the detection signals obtd. by the connected solid-state image pickup elements with each other, are the detection signals not delaying with time by laminating the ends of semiconductor substrates forming the plural solid-state image pickup elements to each other thereby forming the long-sized solid-state image pickup element. CONSTITUTION:The end of the compd. semiconductor substrate 3B is etched to a shape having a projecting part and this compd. semiconductor substrate 3B is stuck onto a supporting substrate 11 so that the end of the compd. semiconductor substrate 3A and the etched end of the compd. semiconductor substrate 3B overlap on each other. The photoelectric conversion parts formed at the ends of the respective compd. semiconductor substrates 3A, 3B are removed by etching. The photoelectric conversion part 1A-1, 1B-1 formed at the ends of the compd. semiconductor substrates 3A, 3B are prevented from being damaged by cutting if the substrates are formed in such a manner and, therefore, the photoelectric conversion part 1A-1, 1A-2..., 1B-1, 1B-2... which are not damaged are formed on one straight line. IR images free from the time lag are obtd. in spite of scanning by a mirror.

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, and more particularly to a long-sized solid-state image pickup device having a plurality of photoelectric conversion units.

In recent years, it has been increasingly desired to detect an object to be detected with a high resolution, or in order to eliminate the need for providing a complicated scanning means such as a mirror, a solid-state image pickup device having a plurality of photoelectric conversion sections is provided. There is a demand for a solid-state image sensor in which elements are linearly arranged in a long dimension.

[0003]

2. Description of the Related Art Conventionally, a compound semiconductor substrate such as mercury, cadmium, tellurium (HgCdTe) having a predetermined diameter has been used.
Alternatively, the compound semiconductor substrate having a HgCdTe crystal provided on a CdTe substrate having a predetermined diameter is used as the HgCdTe substrate, or a photoelectric conversion unit including a pn junction by introducing impurity atoms of a reverse conductivity type with respect to the HgCdTe crystal in a predetermined pattern. To provide.

When forming a solid-state image pickup device having a size longer than the diameter of this compound semiconductor substrate, a solid-state image pickup device having a plurality of photoelectric conversion portions is cut out from this compound semiconductor substrate into a rectangular shape, and the semiconductor cut out into the rectangular shape is cut out. A method of arranging the substrates in a straight line is adopted.

However, when a plurality of solid-state image pickup devices are cut out from a compound semiconductor substrate, stress is easily applied to the cut-out end portion of the compound semiconductor substrate at the time of cutting, and defects are likely to occur. As shown in the plan view, the cut ends of the compound semiconductor substrates 3A and 3B are attached to an unillustrated sapphire substrate or the like with an adhesive so that the ends thereof are staggered.

Since the photoelectric conversion parts 1A-1 and 1B-1 formed at the end portions of the compound semiconductor substrates 3A and 3B have defects that occur during cutting, they are removed by means of etching or the like. As a result, the long-sized solid-state imaging device 2 is obtained without being used.

[0007]

By the way, in the structure in which the ends of the thus cut compound semiconductor substrates 3A, 3B are placed alternately, the photoelectric conversion parts 1A-1, 1A-1, 3B formed on the respective substrates 3A, 3B are arranged. 1A-2, 1A-3 ... and 1B-1, 1B-2, 1B-3 ... are not arranged on a straight line, and the photoelectric conversion units 1A-1, 1A-2, 1A-3.
When a detection signal obtained from the light incident on 1B-1, 1B-2, 1B-3 ... Is scanned by an optical system such as a mirror as shown by an arrow A, the scanned detection signal is detected by the compound semiconductor substrate 3A. , 3B arranged in a row in each of the photoelectric conversion units 1A-1, 1A-2,
Between the detection signals obtained at 1A-3 ... and 1B-1,1B-2,1B-3 ...
As a result, a time delay phenomenon occurs, and the detection target object cannot be detected with high accuracy in terms of time.

An object of the present invention is to solve the above problems and to provide a solid-state image pickup device in which a detection signal obtained between connected solid-state image pickup devices becomes a detection signal which is not delayed in time. Is.

[0009]

According to the solid-state image pickup device of the present invention, when a solid-state image pickup device having a plurality of photoelectric conversion parts is connected to form a long-sized solid-state image pickup device as described in claim 1. In this case, the semiconductor substrate on which the plurality of solid-state imaging devices are formed is formed by laminating the end portions of each other.

Further, as described in claim 2, the length and thickness of the semiconductor substrate are appropriately changed, and the photoelectric conversion portion of the stacked semiconductor substrates is provided with a focus of a condenser lens for condensing incident light on the image pickup device. Characterized by matching with the surface.

Further, as described in claim 3, when stacking the semiconductor substrates on which the solid-state imaging device is formed, a refractive index adjusting member is provided between the semiconductor substrate and the condenser lens so that the condenser lens is It is characterized in that the focal plane and the photoelectric conversion section of the stacked solid-state imaging device are matched.

[0012]

In the solid-state imaging device of the present invention, the semiconductor substrate on which the photoelectric conversion section is formed is cut and arranged so that the ends of the semiconductor substrate overlap with each other, and the photoelectric conversion section formed at the end of the semiconductor substrate is removed. It is removed by etching so that incident light is transmitted through this etched portion and reaches the photoelectric conversion portion of the lower semiconductor substrate.

Further, if the semiconductor substrates on which the photoelectric conversion portions are formed as described above are simply overlapped at the end portions, the photoelectric conversion portions may not match the focal plane of the condenser lens. The thickness and length of the semiconductor substrate to be formed and cut are adjusted to predetermined dimensions as appropriate and cut, and the photoelectric conversion units arranged are stacked stepwise along the focal plane of the condenser lens. Deploy.

FIG. 4 shows the wavelength of the light beam incident on the condenser lens with respect to the position in the radial direction from the center O of the condenser lens,
The relationship of the focal planes is shown. In Fig. 4, the vertical axis indicates the value obtained by standardizing the image height. Since the image height is 10 mm, the value of 1.00 is 10
It corresponds to mm. The horizontal axis indicates the position in the horizontal direction from the center O of the condenser lens, and the curves a, b, c, d, e, f show the condenser lens at wavelengths of 8000 nm, 9000 nm, 10000 nm, 11000 nm, 12000 nm, 13000 nm, respectively. The focal plane is indicated by a curve that connects the focal points when the light enters.

As described above, the light incident on the condenser lens has different focal planes connecting the positions of the focal points where the incident light transmitted through the condenser lens forms an image, depending on the wavelength of the light. The position and shape of the focal plane are confirmed, and the photoelectric conversion units of the solid-state imaging device are stacked stepwise so as to match the focal plane.

Further, a refractive index adjusting member is provided on one side of the semiconductor substrate on which the photoelectric conversion section is formed so that each photoelectric conversion section formed on the stacked substrates matches the focal plane of the condenser lens.

[0017]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 (a) is a plan view of the solid-state image sensor of the present invention, and FIG. 1 (b) is a sectional view of the solid-state image sensor of the present invention.

As shown in FIGS. 1 (a) and 1 (b), the p-type
The p-type HgCdTe crystal of the compound semiconductor substrate 3A made of a CdTe substrate formed on the surface of the HgCdTe crystal by vapor phase epitaxy
The photoelectric conversion units 1A-1, 1A-2, 1A-3 ... Are provided by introducing n-type impurity atoms at a pitch of 50 μm with a size of μm × 30 μm to form the solid-state image pickup device 2A.

The compound semiconductor substrate 3B made of a CdTe substrate on the surface of which a p-type HgCdTe crystal is formed by vapor phase epitaxy is used.
A p-type HgCdTe crystal with dimensions of 30 μm × 30 μm and 50
Introducing n-type impurity atoms at a pitch of μm to provide photoelectric conversion units 1B-1, 1B-2, 1B-3 ..., And to form a solid-state imaging device 2B.

Each of the compound semiconductor substrates 3A and 3B described above is cut into a rectangular shape from a CdTe substrate having a diameter of 3 inches. Such an end portion of the compound semiconductor substrate 3B is selectively etched into a shape having a protruding portion, and the substrate 3B is attached to the supporting substrate 11 made of quartz with an adhesive to remove the compound semiconductor substrate 3A. Edge and etched compound semiconductor substrate
Make the ends of 3B overlap each other.

Then, the compound semiconductor substrate 3A is cut at a distance of 50 μm from the photoelectric conversion section 1A-1 formed at the end portion, and the compound semiconductor substrate 3B is cut at the photoelectric conversion section 1B-2 formed at the end portion. Try to cut at a distance of 50 μm.

Then, the photoelectric conversion portions formed by the dotted lines and formed at the end portions of the respective compound semiconductor substrates 3A and 3B are removed by etching. In this way, the photoelectric conversion parts 1A-1 and 1B formed at the ends of the compound semiconductor substrates 3A and 3B are formed.
-1 is the state where no damage is caused by cutting, so the photoelectric conversion units 1A-1, 1A-2 ... and 1B-1, 1B- where damage is not in a straight line
2 is formed, an infrared image with no time lag can be obtained even if the mirror scans in the direction of arrow A.

A second embodiment of the present invention is shown in FIG. As shown in FIG. 4, the light incident on the condenser lens has different focal planes that connect the focal points where the incident light transmitted through the condenser lens forms an image, depending on the wavelength of the light. Check the shape of the focal plane of the condensing lens according to.

Then, as shown in FIG. 2, a supporting substrate 11 made of quartz or the like having a step shape along the shape of the focal plane 12 is processed, and a predetermined solid-state image pickup device is formed on the step supporting substrate 11. In the compound semiconductor substrate 3 having the photoelectric conversion part 1 formed therein, the thickness and the length of the compound semiconductor substrate 3 are adjusted so that the photoelectric conversion part 1 follows the shape of the focal plane 12, and the thickness and the length are adjusted. The compound semiconductor substrate 3 is bonded onto the stepped support substrate 11 using an adhesive.

Although only one photoelectric conversion unit 1 is shown in FIG. 2, a plurality of photoelectric conversion units may be arranged at a narrow pitch so as to follow the shape of the focal plane 12. A third embodiment of the present invention is shown in FIG. The third embodiment is a further improvement of the first embodiment, and as shown in FIG. 1 (b), a compound semiconductor substrate having photoelectric conversion parts 1A-1, 1A-2, 1A-3 ...
When the thickness of the compound semiconductor substrate 3B on which 3A and the photoelectric conversion parts 1B-1, 1B-2, 1B-3 ...
-1,1A-2,1A-3 ... and the photoelectric conversion units 1B-1,1B-2,1B-3 ... do not match the focal plane of the condenser lens.

Therefore, the photoelectric conversion units 1A-2, 1A-3, ... And the photoelectric conversion units 1B-1, 1B-2, 1B-3 ,. A refractive index adjusting member 13 made of germanium is installed on the conversion units 1A-2, 1A-3 ....

The photoelectric conversion units 1A-2, 1A-3, ... And the photoelectric conversion units 1B-1, 1B-2, 1B-3, ... Form an HgCdTe layer on a CdTe substrate, and the HgCdTe layer is photoelectrically converted. The parts 1A-2, 1A-3, ... And the photoelectric conversion parts 1B-1, 1B-2, 1B-3 ,.

The refractive index adjusting member 13 uses a germanium substrate having a refractive index of 4, and the thickness t ₁ of the refractive index adjusting member 13 on the photoelectric conversion parts 1A-2, 1A-3, 1A-4 is 1067 μm. , Photoelectric conversion part
Since the CdTe substrate exists on 1A-1, the thickness t ₂ of the refractive index adjusting member 13 is set to 470.5 μm in consideration of the transmittance of the CdTe substrate.

In this way, the photoelectric conversion units 1A-1, 1A-2, 1A
-3 ... and the photoelectric conversion units 1B-1, 1B-2, 1B-3 ...
-1,1A-2,1A-3 ... Since the refractive index adjusting member 13 is disposed on the photoelectric conversion units 1A-1,1A-2,1A-3 ..., and the photoelectric conversion units 1B-1,1.
B-2, 1B-3 ... When infrared rays are radiated from above using a condenser lens, the photoelectric conversion units 1A-1, 1A-2, 1A-3 ... and the photoelectric conversion units 1B-1, 1B- from the light source. The optical distances to 2,1B-3 ... are equal.

Therefore, the photoelectric conversion units 1A-1, 1A-2, 1A-3 ...
Then, the photoelectric conversion units 1B-1, 1B-2, 1B-3 ... Align with the focal plane of the condenser lens, and a higher performance solid-state image sensor can be obtained as compared with the first embodiment. . In addition to germanium, the above-mentioned refractive index adjusting member may be any infrared transmitting member such as Si or CdTe substrate.

As shown in the plan view of FIG. 3 (b), the signal processing device 14 for processing the signals of the photoelectric conversion units 1A-1, 1A-2, 1A-3 ... And the photoelectric conversion unit 1B-1. , 1B-2, 1B-3 ... Are provided with a signal processing device 15, and the signals obtained by the photoelectric conversion units are processed.

As described above, according to the solid-state image pickup device of the present invention, it is not necessary to use the photoelectric conversion parts formed at the cut ends of the semiconductor substrate, and the photoelectric conversion parts are arranged in a line. Therefore, when the signal obtained by the photoelectric conversion unit is scanned, a detection signal with no time delay is obtained.

Further, since the photoelectric conversion parts of the stacked solid-state image pickup elements are aligned with the focal plane of the condenser lens, a high-resolution solid-state image pickup element can be obtained. Although the present embodiment has been described by using an example of a solid-state imaging device having photoelectric conversion units arranged in a line, the present invention can be applied to a solid-state imaging device having photoelectric conversion units arranged in a plurality of columns. is there.

[0034]

As described above, according to the solid-state image pickup device of the present invention, it is possible to obtain a solid-state image pickup device which does not cause a time delay in a scanning signal when scanning is performed by a condenser lens.

Further, since the photoelectric conversion part is aligned with the focal plane of the condenser lens, there is an effect that a high resolution solid-state image pickup device can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view and a sectional view of a first embodiment of a solid-state image sensor according to the present invention.

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

3A and 3B are a sectional view and a plan view of a third embodiment of the solid-state image pickup device of the present invention.

FIG. 4 is an explanatory diagram of a focal plane according to a wavelength of a condenser lens.

FIG. 5 is a plan view of a conventional solid-state image sensor.

[Explanation of symbols]

 1,1A-1,1A-2,1A-3… Photoelectric converter 1B-1,1B-2,1B-3… Photoelectric converter 2,2A, 2B Solid-state image sensor 3,3A, 3B Compound semiconductor substrate 11 Support Substrate 12 Focal plane 13 Refractive index adjusting member 14, 15 Signal processing device

Front Page Continuation (72) Inventor Ouzaki Kazuo 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (3)

[Claims] 1. A plurality of photoelectric conversion units (1A-1, 1A-2, 1A-3 ...,
1B-1, 1B-2, 1B-3 ...) are connected to form a long-sized solid-state image pickup device (2A, 2B), the solid-state image pickup device (2A , 2B) is formed on the semiconductor substrate (3A, 3B) by laminating the ends thereof on each other. 2. The semiconductor substrate (3A, 3B) according to claim 1, wherein the length and thickness of the semiconductor substrate (3A, 3B) are appropriately changed and laminated.
B) photoelectric conversion unit (1A-1,1A-2,1A-3 ..., 1B-1,1B-2,1B-3
.) Is matched with the focal plane (12) of the condensing lens of the incident light incident on the solid-state image sensor. 3. When stacking the semiconductor substrates (3A, 3B) on which the solid-state imaging device according to claim 1 or 2 is laminated, a refractive index adjusting member (13) is used as the semiconductor substrate (3A, 3B). The photoelectric conversion unit (1A-1, 1A-2, 1A-3 ..., 1B-1, 1 of the solid-state image pickup device, which is provided between the condenser lenses and laminated with the focal plane (12) of the condenser lenses, is stacked.
B-2, 1B-3 ...) are matched.