JPH0730083A - Infrared ray sensor - Google Patents

Abstract

PURPOSE:To provide the title infrared ray sensor capable of simply and easily avoiding the generation of thermal stress without using a wirebonding at all in relation to the modification of the constitution of the infrared ray sensor. CONSTITUTION:The title hybrid infrared ray sensor composed of photodiode array 1a and silicon CCD coupled with each another is provided with a bump 1d of this silicon CCD 2, wiring 1c and bonding pads 1e for reading-out signals on a substrate 1 overlaid with the photodiode arrays 1a so that this silicon CCD 2 may be divided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in the structure of infrared detecting elements. In the conventional infrared sensing element that is wired by wire bonding, there is a failure due to the contact of adjacent wires, and the silicon substrate on which the charge-coupled element is formed and the mercury on which the infrared sensing part is formed
In the infrared detection element that connects the cadmium-tellurium substrate with the wiring substrate via the bump, the thermal stress causes a failure due to the difference in the thermal expansion coefficient between the silicon substrate and the mercury-cadmium-tellurium substrate. .

Under the circumstances as described above, there is a demand for an infrared detecting element that does not use wire bonding and can prevent the occurrence of thermal stress.

[0003]

2. Description of the Related Art A conventional front-illuminated infrared detecting element will be described in detail with reference to FIGS. 6 is a diagram showing a first example of a conventional infrared detecting element, FIG. 7 is a diagram showing a second example of a conventional infrared detecting element, and FIG. 8 is a manufacturing method of a second example of the conventional infrared detecting element. It is a figure showing in order of a process.

A first example of a conventional hybrid type infrared detecting element is, as shown in the side view of FIG. 6 (a) and the plan view of FIG. 6 (b), mercury-cadmium-tellurium (hereinafter referred to as HgCdTe).
(Abbreviated as ") Photodiode array 41 formed in crystal
a and a silicon charge coupled device (hereinafter, abbreviated as silicon CCD) 42 are bonded on a substrate 41 made of ceramic,
Photodiode array 41a and relay wiring part 41b of substrate 41
Between the relay wiring portion 41b and the silicon charge coupled device 42
And a silicon CCD 42 and an external signal pin (not shown) are electrically connected by a wire 43 made of aluminum.

A second example is HgCdTe as shown in FIG.
Photodiode array 51 and silicon CCD 52
Are electrically connected to each other by a bump 54b and a wiring 54a provided on a wiring substrate 54 made of sapphire.
52 is a supporting substrate made of insulating gallium arsenide (GaAs)
It is glued and fixed to 53, and this substrate 53 is attached to the cooling head 55.
It is fixed to.

In order to manufacture the infrared detecting element of the second example, first, as shown in FIG. 8 (a), the bump 51a of the photodiode array 51 formed on the HgCdTe crystal and the incident window made of sapphire are used. The bumps 54b connected by the wirings 54a provided on the wiring board 54 having 54c are pressed to be electrically connected.

Next, as shown in FIG. 8B, the wiring board 54
And the bumps 52a of the silicon CCD 52 are pressed to electrically connect. Then, as shown in Fig. 8 (c),
The silicon CCD 52 is adhered and fixed to the support substrate 53.

Finally, as shown in FIG. 7, this supporting substrate 53
Is bonded and fixed to the cooling head 55 of the container, and the bonding pad 52e of the silicon CCD 52 and an external signal pin (not shown) are electrically connected by a wire made of aluminum.

When manufacturing the wiring board 54 made of sapphire, the wiring 54a and the bumps 54b are first formed, and the wiring board 54 is divided into individual wiring boards 54, which are then ultrasonically processed to form an incident window.
54c is formed, but wiring 54a and bump 54b are formed during this processing.
And the adhesion to the wiring board 54 made of sapphire is poor.

An aperture for preventing stray light and a bandpass filter are separately provided in these infrared detecting elements.

[0011]

In the first example of the conventional infrared detecting element described above, since the wire having the outer diameter of 25 μm is used, it is difficult to arrange the wires at a high density, and the bonding work is difficult. It is complicated and there is a failure due to contact between adjacent wires. Further, in the second example of the infrared detecting element in which the conventional silicon substrate on which the charge coupled device is formed and the HgCdTe substrate on which the infrared detecting portion is formed are connected by the bump of the wiring substrate, the silicon substrate and the HgCd
There is a problem that thermal stress due to the difference in the coefficient of thermal expansion from the Te substrate occurs in the bump joints, resulting in a poor electrical connection. There is a problem in that the formed wiring 54a and bumps 54b and the wiring board 54 have poor adhesion and are broken.

In view of the above situation, the present invention has an object to provide an infrared detecting element capable of easily and easily preventing the occurrence of thermal stress without using wire bonding.

[0013]

The infrared sensing element of the present invention is a front-illuminated hybrid infrared sensing element in which a photodiode array and a charge-coupled device are combined, and the photodiode array is formed. The charge-coupled device is provided with a connection portion with the charge-coupled device, a wiring for reading a signal, and a bonding pad on the substrate, and the charge-coupled device is divided.

[0014]

That is, in the present invention, since the coupling portion with the charge coupled device, the wiring for reading the signal and the bonding pad are provided on the substrate on which the photodiode array is formed, the photodiode array and the silicon CCD can be connected. Since no bonding wire is used, it is possible to prevent contact failure between adjacent bonding wires.

In addition, when HgCdTe and a substrate other than silicon are laminated, the silicon CC is dimensioned to withstand the stress caused by the thermal cycle between room temperature and 77K in use.
Since D is divided and mounted, it is possible to prevent the occurrence of thermal stress at the bump bonding portion due to the difference in thermal expansion coefficient between silicon and HgCdTe.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a diagram showing the structure of an infrared detecting element according to the first embodiment of the present invention, FIG. 2 is a diagram showing the structure of an infrared detecting element of the second embodiment according to the present invention, and FIG. 3 is a third embodiment according to the present invention. FIG. 4 is a diagram showing the structure of the infrared detecting element of the embodiment of the present invention, FIG. 4 is a diagram showing the structure of the infrared detecting element of the fourth embodiment of the present invention, and FIG. 5 is the infrared detecting element of the fourth embodiment of the present invention. It is a figure showing a manufacturing method in order of a process.

In the first embodiment according to the present invention shown in FIG. 1, as shown in the side sectional view of FIG. 1 (a), cadmium tellurium (CdTe) 111a and HgCdTe 111b are laminated, and this Hg
A wiring 1c having a bump 1d and a bonding pad 1e is provided on the surface of the substrate 1 having the photodiode array 1a formed in the center of the CdTe 111b through an insulating film 1b.
As shown in the plan view of (b), a plurality of silicon Cs whose bump joints are divided into dimensions that can withstand the stress of thermal cycles.
The bump 2a of the CD 2 and the bump 1d are pressure-bonded to each other, and the bonding pad 1e and an external signal pin (not shown) are electrically connected by a wire 3 made of aluminum.

Instead of the above-mentioned substrate 1 in which CdTe and HgCdTe are laminated, a heterogeneous substrate, for example, a substrate in which cadmium zinc tellurium (CdZnTe) and HgCdTe are laminated, or a substrate in which sapphire and HgCdTe are laminated, or silicon And HgCd
Substrates laminated with Te, or gallium arsenide (GaAs) and Hg
If a substrate laminated with CdTe is used, it is possible to further reduce the stress due to the difference in coefficient of thermal expansion with the silicon CCD 2.

In the second embodiment according to the present invention shown in FIG. 2, HgCdTe121b is embedded in the central portion of cadmium tellurium (CdTe) 121a as shown in the side sectional view of FIG. Bumps 11d are formed on the surface of the substrate 11 on which the photodiode array 11a is formed, with an insulating film 11b interposed therebetween.
A wiring 11c including a bonding pad 11e and a bonding pad 11e is provided. As shown in the plan view of FIG. 2 (b), the bumps 12a of the plurality of silicon CCDs 2 are divided into a size such that the bonding portion of the bump can withstand the stress of thermal cycle. And the bump 11d are pressure-bonded to each other, and the bonding pad 11e and an external signal pin (not shown) are electrically connected by a wire 13 made of aluminum.

In the third embodiment of the present invention shown in FIG. 3, as shown in the side sectional view and the plan view of FIG. 3 (a), silicon 131a and HgCdTe 131b are laminated, and this HgCdTe is formed.
A wiring 21c including a bump 21d and a bonding pad 21e is provided on the surface of the substrate 21 on which the photodiode array 31a is formed in the central portion of 131b via an insulating film 21b.
The bumps 22a of the silicon CCD 22 made of silicon and having the bumps 22a formed on the lower surface of the substrate 21 and wirings are formed in other regions so that the infrared transmitting region 22b for transmitting infrared rays is formed in the central portion. The bumps 21d formed on the surface of the
A wire 23 made of aluminum electrically connects between e and an external signal pin (not shown).

In a fourth embodiment according to the present invention shown in FIG. 4, as shown in the side sectional view and the plan view of FIG. 4 (a), silicon 141a and HgCdTe 141b are laminated, and this HgCdTe is laminated.
A wiring 31c having a bump 31d and a bonding pad 31e is provided on the surface of the substrate 31 having the photodiode array 31a formed in the center of 141b via an insulating film 31b.
Band pass filter 32b that transmits infrared rays in the center
And the infrared absorption film 32c is formed in other areas,
The bump 32a of the silicon CCD 32 made of silicon with the bump 32a formed on the lower surface is connected to the bump 31d formed on the surface of the substrate 31 by pressure bonding, and the bonding pad 31e and an external signal pin (not shown) are connected by aluminum. Are electrically connected by a wire 33 consisting of.

In order to manufacture the infrared detector of the fourth embodiment according to the present invention, first, as shown in FIG. 5 (a), cadmium tellurium (CdTe) 141a and HgCdTe 141b are laminated, and Bumps 31d and bonding pads are formed on the wiring 31c formed through the insulating film 31b on the surface of the substrate 31 on which the photodiode array 31a is formed in the center of the HgCdTe 141b.
31e and.

Next, a bandpass filter section is provided at the center.
32b, infrared absorption film 32c is formed in the other area,
The silicon CCD 32 on which the bumps 32a are formed and the substrate 31 are opposed to each other as shown in FIG. 5 (b), the bumps 31d of the substrate 31 and the bumps 32a of the silicon CCD 32 are connected by pressure bonding, and the substrate 31 is cooled by the container. Adhesive and fixed to the head 34,
Bonding pad 31e formed on wiring 31c on substrate 31
And an external signal pin (not shown) are electrically connected by a wire 33 made of aluminum.

[0024]

As is apparent from the above description, according to the present invention, the structure in which the charge coupled device of the infrared detection device is divided causes the contact failure of the bonding wire and the difference in the coefficient of thermal expansion of the substrate. It is possible to provide an infrared sensing element which has advantages such as prevention of thermal stress failure of the bump bonding portion, and which can be expected to have significant economic and reliability improvement effects.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of an infrared detection element according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a structure of an infrared detection element according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a structure of an infrared detection element of a third embodiment according to the present invention.

FIG. 4 is a diagram showing a structure of an infrared detection element according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a method of manufacturing an infrared detection element according to a fourth embodiment of the present invention in the order of steps.

FIG. 6 is a diagram showing a first example of a conventional infrared detecting element.

FIG. 7 is a diagram showing a second example of a conventional infrared detecting element.

FIG. 8 is a diagram showing a manufacturing method of a second example of the conventional infrared detecting element in the order of steps.

[Explanation of symbols]

 1,11,21,31 Substrate 111a CdTe 111b HgCdTe 121a CdTe 121b HgCdTe 131a Silicon 131b HgCdTe 141a Silicon 141b HgCdTe 1a, 11a, 21a, 31a Photodiode array 1b, 11b, 21b, 31b Insulating film 1c, 11c, 21c, 31c Wiring 1d, 11d, 21d, 31d Bump 1e, 11e, 21e, 31e Bonding pad 2,12,22,32 Silicon CCD 2a, 12a, 22a, 32a Bump 3,13,23,33 Wire 22b Infrared transparent area 32b Bandpass Filter part 32c Infrared absorption film 34 Cooling head

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshio Watanabe, Yoshio Watanabe, 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (5)

[Claims] 1. A front-illuminated photodiode array.
A hybrid type infrared sensing element in which (1a) and a charge-coupled device (2) are coupled to each other, which is coupled to the charge-coupled device (2) on the substrate (1) on which the photodiode array (1a) is formed. Part (1d) and wiring (1c) for reading signals and bonding pad (1e) are provided,
An infrared detecting element, wherein the charge-coupled device (2) is divided. 2. The substrate according to claim 1, wherein the substrate is a single crystal of mercury cadmium tellurium (HgCdTe) or a substrate in which cadmium tellurium (CdTe) and mercury cadmium tellurium are laminated or cadmium zinc tellurium (CdZnTe). Substrate in which silicon and mercury / cadmium / tellurium are stacked, substrate in which sapphire and mercury / cadmium / tellurium are stacked, substrate in which silicon and mercury / cadmium / tellurium are stacked, or gallium / arsenic (GaAs) and mercury / cadmium / tellurium An infrared detecting element, which is a substrate in which and are laminated. 3. The substrate according to claim 1 has the laminated substrate structure according to claim 2 only in a region where a photodiode array is formed, and the other coupling portion (1d) and wiring for reading out a signal. An infrared detecting element characterized in that a region forming (1c) and a bonding pad (1e) is made of only the above-mentioned cadmium-tellurium, cadmium-zinc-tellurium, sapphire, silicon or gallium-arsenic. 4. The infrared detecting device according to claim 1, further comprising an infrared transmitting region (22b) formed on the photodiode array, the infrared transmitting region (22b) having no wiring or the like for preventing infrared radiation from entering. . 5. The charge-coupled device according to claim 4, wherein the infrared transmitting region is a bandpass filter portion (32b), and the other region is an infrared absorbing region formed with an infrared absorbing film (32c). Infrared detector element.