JPH05142038A - Manufacture of infrared ray detector and cold shielding - Google Patents

Abstract

PURPOSE:To obtain an infrared ray detector with improved sensitivity characteristics and image quality. CONSTITUTION:A first groove 14 is provided on a surface side in a infrared rays detector where a plurality of infrared rays detection elements 12 are arranged on a substrate 11. A cold shield 13 which consists of nearly plate-shaped member with a plurality of second grooves 15 which reach the first groove 14 and are placed in equal gap in a direction which crosses the first groove 14 is adhered and fixed to a rear-surface side so that a part 16 among a plurality of second grooves 15 is placed at a part among the infrared ray-detection elements 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-element infrared detector having a cold shield and a method for manufacturing the cold shield.

A crystal block made of a multi-element semiconductor having a small energy gap, such as mercury, cadmium, or tellurium, is provided on a support substrate such as sapphire, and a pair of contact electrodes are formed on both sides of the main surface of the crystal block to form a gap between the electrodes. An infrared detecting element having an area as an infrared receiving section is known, and this kind of infrared detecting element is generally used in a state of being cooled to a liquid nitrogen temperature (77 K).

Further, in this type of infrared detector,
In order to increase the detection sensitivity, the viewing angle of infrared rays entering the infrared detection element from the detection target is narrowed as much as possible,
It is desirable to eliminate extra radiation coming from the background other than the object to be detected. For this reason, in general, a cold shield having an infrared transmitting window for determining the visual field is arranged on the front surface of each infrared detecting element in order to limit the viewing angle. The cold shield does not become a source of unnecessary light,
It is cooled together with the infrared detection element.

In the infrared detector provided with such a cold shield, it is desired to improve the sensitivity characteristic or the image quality and to facilitate the manufacture.

[0005]

2. Description of the Related Art FIG. 3 is a transverse sectional view showing the structure of a main part of a conventional infrared detector, and FIG. 4 is a longitudinal sectional view of the same. In the figure, 1 is a support substrate made of sapphire or the like, and a plurality of infrared detection elements 2 are arranged on the support substrate 1. The infrared detecting element 2 has a pair of electrodes formed on both sides of a crystal block of mercury, cadmium, tellurium, etc., and an area between these electrodes is constituted as an infrared receiving section, and a bias current is applied between these electrodes. By so doing, the resistance value that changes according to the intensity of the infrared light that enters the infrared light receiving portion is extracted as a voltage change to an external circuit.

Bumps (stands) 3 made of metal or the like are formed in the vicinity of both ends in the arrangement direction of these infrared detecting elements, and a substantially plate-like cold shield 4 is adhered and fixed onto these bumps 3. Has been done. This cold shield 4 has an infrared transmitting plate 5 which transmits infrared rays such as zinc sulfide (ZnS), the surface of which is blackened, a metal aperture 7 having an infrared transmitting window 6 is provided, and the lower surface transmits infrared rays. An opaque film 8 made of a metal or the like is formed, and an infrared transmitting window 9 is formed by removing a predetermined portion of the opaque film 8.

Only the infrared rays that have passed through the infrared transmission window 6 of the metal aperture 7 and the infrared transmission window 9 of the opaque film 8 are
It is incident on the infrared ray receiving portion of the infrared ray detecting element 2.

[0008]

However, according to the structure of the conventional cold shield, the metal aperture mainly has a visual field in a direction (hereinafter, lateral direction) perpendicular to the array direction (hereinafter, vertical direction) of the infrared detecting elements. Since the opaque film limits the vertical field of view, the viewing angle may differ between each infrared detection element, and the passage loss due to the infrared transmission plate is large, and the cold shield is used as a bump. Since it is installed, it has a drawback that it is vulnerable to vibration, the field of view of the infrared detection element fluctuates and causes noise, and the sensitivity characteristic or image quality is not very good.

There is also a problem that the structure is complicated and the manufacture is not easy. The present invention has been made in view of the above points, and it is an object of the present invention to improve sensitivity characteristics or image quality and to facilitate manufacturing.

[0010]

In order to solve the above-mentioned problems, the following infrared detector and cold shield manufacturing method are provided.

That is, in the infrared detector according to the present invention, a plurality of infrared detecting elements are arranged on a substrate, and the first infrared detecting element is arranged on the front surface side of the infrared detecting element.
Cold shield made of a substantially plate-shaped member having a plurality of second grooves arranged on the back surface side to reach the first groove and arranged at equal intervals in a direction intersecting the first groove. Is bonded and fixed so that the wall portions on both sides of the plurality of second grooves are arranged in the portions between the infrared detection elements.

Further, in the cold shield manufacturing method according to the present invention, a step of forming a first groove on the front surface side of the plate-shaped member that does not reach the back surface of the plate-shaped member, and the plate-shaped member. A plurality of second grooves reaching the first groove on the back surface side of
Forming at equal intervals in a direction intersecting the first groove.

[0013]

According to the infrared detector of the present invention, the second groove on the rear surface side of the cold shield reaches the first groove on the front surface side, and the portion where the first groove and the second groove intersect (continuously). (Portion) is provided with a plurality of openings (penetrating portions) having the same shape, and these openings are used as infrared transmitting windows to regulate the incidence of infrared rays on the corresponding infrared detecting elements. Each opening has the same shape,
Since each infrared detection element corresponds to each infrared detection element, all infrared detection elements have the same field of view.

Further, since the cold shield is adhered and fixed to the substrate in a state in which the portion between the second grooves is located between the infrared detecting elements, it is conventionally supported and fixed only at both ends thereof. In addition to being superior in quake resistance as compared with the configuration of No. 1, the passage loss can be improved as compared with the conventional one because there is no substance in the opening.

On the other hand, according to the cold shield manufacturing method of the present invention, the openings (infrared transmitting windows) having a desired shape can be formed by forming the grooves on both surfaces of the plate-shaped member. It's very easy.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the structure of a cold shield, and FIG. 2 is a sectional view of an infrared detector using this cold shield. In FIG. 2, 11 is a supporting substrate made of sapphire or the like, and a plurality of infrared detecting elements 12 are arranged on the supporting substrate 11. This infrared detection element 12
Is a structure in which a pair of electrodes are formed on both sides of a crystal block of mercury, cadmium, tellurium, etc., and the region between these electrodes is configured as an infrared light receiving part, and by applying a bias current between these electrodes, The resistance value, which changes according to the intensity of the infrared rays incident on the infrared light receiving section, is taken out to the external circuit as a voltage change.

A cold shield 13 having a structure as shown in FIG. 1 is adhered and fixed onto the support substrate 11. The cold shield 13 has a linear first groove 14 formed on the front surface side of a plate-shaped member in the longitudinal direction thereof, and a plurality of second grooves 14 formed on the back surface side in a direction orthogonal to the first groove 14. The grooves 15 are formed at equal intervals over both ends in the short side direction.

The first groove 14 and the second groove 15 have continuous portions, that is, the sum of the depths of the first groove 14 and the second groove 15 is plate-like. Is set to be equal to or larger than the plate thickness of the member of the first groove 1
A rectangular opening is formed at the intersection of 4 and the second groove 15.

As a material of the cold shield 13, a material which does not transmit infrared rays, for example, a metal such as stainless steel or Kovar can be used. Further, a semiconductor such as silicon, a dielectric such as sapphire, or ceramics can be used. In this case, the first groove 14 and the second groove 15 can be used.
It is possible to use a material in which the surface is covered with an antireflection film or blackened, or silicon is doped with a high concentration of impurities so that infrared rays cannot be transmitted.

The first groove 14 and the second groove 15 can be formed by an etching process using a photoresist. That is, it can be formed by applying a resist on the surface of a plate-shaped member, masking and exposing, and then removing the portion to be a groove by etching, and similarly treating the back surface side. The first groove 14 and the second groove 15 can also be formed by mechanically cutting.

As shown in FIG. 2, the cold shield 13 manufactured in this manner is arranged so that the infrared detecting elements 12 are located in the second grooves 15, respectively. An adhesive agent is applied to the end faces of the wall portions 16 on both sides of the above, and is fixed to the support substrate 11 by adhesion.

According to this embodiment, the cold shield 13
The second groove 15 on the back surface side reaches the first groove 14 on the front surface side, and a plurality of identical shapes are formed in a portion (continuous portion) where the first groove 14 and the second groove 15 intersect. It has an opening (penetrating portion). These openings are used as infrared transmitting windows to control the incidence of infrared rays on the corresponding infrared detecting elements 12. Since each opening has the same shape (rectangle) and corresponds to each infrared detecting element 12, all infrared detecting elements 1
2 have the same field of view.

Further, since the cold shield 13 is adhered and fixed to the support substrate 11 with the wall portions 16 on both sides of each second groove 15 positioned between the infrared detection elements 12, only the both end portions thereof are fixed. It is superior in earthquake resistance as compared with the conventional structure in which it is supported and fixed by and is very easy to manufacture.

[0024]

Since the present invention is constructed as described above in detail, the field of view of each infrared detecting element is the same, the passage loss is small, and the vibration resistance is excellent. An effect is provided that an infrared detector with good image quality can be provided.

Further, there is an effect that the manufacturing of the cold shield is facilitated.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a cold shield according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a configuration of a conventional technique.

FIG. 4 is a vertical cross-sectional view showing a configuration of a conventional technique.

[Explanation of symbols]

 11 Support Substrate 12 Infrared Detector 13 Cold Shield 14 First Groove 15 Second Groove 16 Wall

Front page continued (72) Inventor Koji Hirota 1015 Kamiodanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Yukihiro Yoshida 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited

Claims (3)

[Claims] 1. A plurality of infrared detection elements (12) on a substrate (11)
An infrared detector having an array of the first groove (14) on the front surface side and the first groove (14) on the rear surface side.
A cold shield (13) made of a substantially plate-shaped member having a plurality of second grooves (15) reaching the (14) and arranged at equal intervals in a direction intersecting the first groove (14). An infrared detector characterized by being bonded and fixed so that a portion (16) between the plurality of second grooves (15) is arranged in a portion between the infrared detection elements (12). .. 2. The method for manufacturing a cold shield for an infrared detector according to claim 1, wherein a first groove (14) which does not reach the back surface of the plate-shaped member is provided on the front surface side of the plate-shaped member. And a plurality of second grooves (15) reaching the first groove (14) on the back surface side of the plate-shaped member in a direction intersecting the first groove (14). A method of manufacturing a cold shield, comprising the steps of forming at intervals. 3. The cold shield manufacturing method according to claim 2, wherein the first groove (14) and the second groove (15) are formed by an etching process using a photoresist. A method for manufacturing a cold shield, comprising: