JP2833373B2 - Imaging infrared detector and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging infrared detector comprising a large number of infrared detecting elements arranged at a predetermined pitch for detecting infrared light as image information, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, an infrared detecting element of an infrared detector comprises an HgCdTe crystal part mounted on a sapphire substrate, and a pair of electrodes is connected to the HgCdTe crystal part. When the HgCdTe crystal part is irradiated with infrared rays while a predetermined voltage is applied between the pair of electrodes, the voltage between the pair of electrodes fluctuates according to the irradiation amount. In order to detect image information using such an infrared detecting element, a large number of infrared detecting elements 1 are placed on a sapphire substrate 10 as shown in FIG.
2 are arranged at a predetermined arrangement pitch on a straight line, and image information detection light (infrared rays) obtained by the imaging scanning optical system is made incident on such an infrared detection element arrangement area. The image information detection light incident on the infrared detection element array area at each time interval is detected as voltage fluctuation by each infrared detection element 12, and the voltage fluctuation value of each infrared detection element 10 is processed as one pixel data of a reproduced image. Is done.

In order to detect good image information with such an infrared detector for imaging, it is necessary to use individual infrared detecting elements 10
It is necessary to increase the detection sensitivity. More specifically, only the image information detection light focused by the above-described imaging scanning optical system should be made incident on each infrared detection element 10, and the incidence of other infrared rays, that is, background light that is noise, is as large as possible. Must be eliminated. Therefore, conventionally, as shown in FIG. 8, a background light regulating member 14 called a cold aperture is provided in the infrared detecting element array region, and the background light regulating member 12 corresponds to the position of each infrared detecting element 12. Aperture or opening 1 in place
6 are formed. The cross-sectional shape of the opening 16 may be any of a rectangular shape and a circular shape, and the size of the opening is set to a size corresponding to the incident angle α of the image information detection light.
As a result, the incidence of background light to each infrared detecting element 10 is prevented as much as possible, and the detection sensitivity of each infrared detecting element 10 is enhanced. During operation, the background light regulating member, that is, the cold door aperture 14 itself is cooled down to about 80 K (-200 C) as the name implies, and infrared radiation (noise) from the cold door aperture 14 is suppressed as much as possible. Can be

[0004]

However, noise light inevitably exists in the angle region of the incident angle α defined by the above-described imaging optical system. As shown in FIG.
The noise light N that is incident on the side surface is also included.
Note that the opening 16 has a size larger than the detection area of the infrared detection element 10. Such noise light N is diffusely reflected on the side surface of the infrared detecting element 12 to become stray light, and is detected by the adjacent infrared detecting element 12, so that the reproduced image becomes unclear or, in a remarkable case, a ghost occurs. . Therefore, an object of the present invention is to provide an imaging infrared detector including a large number of infrared detection elements arranged at a predetermined arrangement pitch for detecting infrared light as image information, the light being incident on a side surface of each infrared detection element. An object of the present invention is to provide an imaging infrared detector configured to prevent the noise light from being detected by an adjacent infrared detection element. Another object of the present invention is to provide a manufacturing method for manufacturing the above-described infrared detector for imaging at low cost and economically.

[0005]

According to the present invention, there is provided an imaging infrared detector comprising a plurality of infrared detectors arranged at a predetermined arrangement pitch on a substrate, the intermediate between two adjacent infrared detectors. setting a light-shielding barrier position,
The light shielding barrier is made of the same material as the infrared detecting element.
That it is characterized. In the manufacturing method according to the present invention, first, an infrared detecting element material layer is formed on a substrate, and a first resist is applied on the infrared detecting element material layer in correspondence with the arrangement of the infrared detecting elements. At the same time, the second resist is applied in the middle of the two adjacent arrangement points along the cross direction and at least over the size of the infrared detecting element. Thereafter, the infrared detecting element material layer is subjected to an etching treatment to remove the infrared detecting element material other than the application locations of the first and second resists, thereby forming the infrared detecting elements at a predetermined arrangement pitch and A light-shielding barrier is formed at an intermediate position between the two adjacent infrared detecting elements, and then the first and second resists are removed.

[0006]

As apparent from the above description, in the infrared detector for imaging according to the present invention, a light-shielding barrier is provided at an intermediate portion between two infrared detecting elements adjacent to each other. Even if the noise light incident on the side surface of the element is reflected toward the other infrared detecting element, the reflected noise light is not blocked by the light shielding barrier and does not reach the other infrared detecting element. Further, in the manufacturing method according to the present invention, when the first resist is applied to the infrared detection element material layer in correspondence with the arrangement of the infrared detection elements, the first resist is applied at an intermediate point between the two adjacent arrangement points. Since the second resist is also applied along the transverse direction and at least over the dimensions of the infrared detecting element, after the infrared detecting element material layer is subjected to the etching treatment, the infrared ray is applied at a predetermined arrangement pitch. The detection element is formed, and a light-shielding barrier is formed at an intermediate position between two adjacent infrared detection elements. That is, in the manufacturing method according to the present invention, a light-shielding barrier can be obtained at the same time when the infrared detecting element is formed.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an infrared detector for imaging according to the present invention; FIG. FIG. 1 is a cross-sectional view of a part of an imaging infrared detector according to the present invention. This infrared detector has basically the same configuration as that shown in FIG. In FIG. 1, the same reference numerals are used for the same components as those in FIG. In the embodiment shown in FIG. 1, the substrate 10 is formed as a sapphire substrate, on which a number of infrared detecting elements 12 made of HgCdTe crystal are mounted. These infrared detecting elements 12 are arranged in a straight line at a predetermined arrangement pitch, for example, at an interval of 100 microns.
The dimensional shape of the second is, for example, 50 × 50 microns. A background light regulating member, that is, a cold door aperture 14 is provided in such an infrared detecting element array region, and an opening 16 is formed in the cold door aperture 14. As described above, the cold aperture 14 serves to prevent the background light from being incident on the individual infrared detecting elements 12 as much as possible, thereby increasing the detection sensitivity of each infrared detecting element 12.

According to the present invention, a light-shielding barrier 18 is provided at an intermediate position between two infrared detecting elements 12 adjacent to each other, and the light-shielding barrier 18 is provided between the two infrared detecting elements 1.
2 and extends over at least the dimension of the infrared detecting element. For this reason, as shown in FIG. 1, even if the noise light N incident on the side surface of one of the infrared detection elements 12 is irregularly reflected and becomes stray light, even if it goes to the adjacent infrared detection element 12, the stray light is It does not reach the adjacent infrared detecting element 12 because it is blocked by the barrier 18.

Referring to FIG. 2, there is shown a modified embodiment of the imaging infrared detector according to the present invention shown in FIG. 1, in which the thickness of the cold door aperture 14 is increased, whereby the light shielding barrier is increased. A top surface 18 provides a bearing surface for the cold aperture 14. When the imaging infrared detector is vibrated by an external force during its operation, the cold door aperture 14 is also likely to vibrate. At this time, the reproduced image is disturbed. By using the bearing surface, the cold door aperture 14 can be effectively suppressed. Note that it is preferable that the top surface of the light-shielding barrier 18 and the cold door aperture 14 are appropriately fixed with an adhesive or the like.

In the embodiment shown in FIGS. 1 and 2,
It is preferable that the light-shielding barrier 18 is formed of the same material as that of the infrared detecting element 12. In this case, it is not necessary to introduce a special process for forming the light-shielding barrier 18 in the manufacturing process of the imaging infrared detector. Can be done. Hereinafter, a method for manufacturing such an imaging infrared detector will be described with reference to FIGS.

First, as shown in FIG. 3, an infrared detecting element material layer, that is, an HgCdTe crystal layer 2 is formed on a sapphire substrate 10.
0 is formed in a known manner, and then as shown in FIG.
A first resist 22 is applied on the HgCdTe crystal layer 20 in correspondence with the arrangement of the infrared detecting elements 12, and at the same time, at the middle of the two adjacent arrangements, along the transverse direction and at least the infrared. Detection element 1
The second resist 24 is applied over a dimension of 2 or more. After that, the HgCdTe crystal layer 20 is subjected to an etching process, and as shown in FIG.
And the HgCdTe crystal material other than the application location of 24 is removed, and thereby the infrared detecting elements 12 are arranged at a predetermined arrangement pitch.
Is formed and a light-shielding barrier 18 is formed at an intermediate position between two adjacent infrared detecting elements, and then the first and second resists are removed as shown in FIG. Subsequently, the sapphire substrate 1 is
A pair of electrodes (not shown) are formed on the substrate 0 by a well-known method, and thereafter, a cold aperture is installed to obtain an imaging infrared detector as shown in FIGS. As described above, when the light-shielding barrier 18 is formed together with the infrared detection element 12, the imaging infrared detector according to the present invention can be used without substantially changing the manufacturing process of the conventional imaging infrared detector. However, if necessary, the light-shielding barrier 1 may be used.
Needless to say, 8 may be additionally formed on the sapphire substrate 10 using a material different from the infrared detecting element 12.

Referring to FIG. 7, another embodiment of the imaging infrared detector according to the present invention is shown. In this embodiment, the light shielding barrier 18 ′ is integrally formed so as to be suspended from the cold door aperture 14. Is done. The cold aperture 14 may be made of an appropriate metal material capable of precision processing, for example, Kovar, stainless steel, aluminum, or the like, or a semiconductor material such as Si or ZnS, or a ceramic. 'Is formed integrally with the same material as the cold aperture 14. In such an embodiment, the vibration of the cold door aperture 14 can be effectively prevented. Preferably, the light shielding barrier 1 is used.
The bottom surface of 8 'is appropriately fixed on the sapphire substrate 10.

[0013]

As is clear from the above description, in the imaging infrared detector according to the present invention, even if noise light incident on the side surface of each infrared detection element is irregularly reflected there and becomes stray light, The stray light is reliably prevented from reaching the adjacent infrared detecting element by the light-shielding barrier, so that a clear reproduced image can be obtained. In addition, in the manufacturing method according to the present invention, since the manufacturing process of the conventional imaging infrared detector can be used without substantially changing the same, the imaging infrared detector according to the present invention can be used without additional cost. It is possible to obtain.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing an embodiment of an imaging infrared detector according to the present invention.

FIG. 2 is a longitudinal sectional view similar to FIG. 1, showing a modification of the embodiment of FIG. 1;

FIG. 3 is a partial sectional view showing an initial process of the manufacturing method according to the present invention.

FIG. 4 is a partial cross-sectional view similar to FIG. 3, showing a process that follows the process shown in FIG. 3;

5 is a partial cross-sectional view similar to FIG. 4, illustrating a process subsequent to the process illustrated in FIG. 4;

6 is a partial cross-sectional view similar to FIG. 5, showing a process that follows the process shown in FIG. 5;

FIG. 7 is a partial vertical sectional view showing another embodiment of the imaging infrared detector according to the present invention.

FIG. 8 is a partial longitudinal sectional view showing a conventional imaging infrared detector.

FIG. 9 is a partial cross-sectional view similar to FIG. 8, and is an explanatory view illustrating a problem of a conventional infrared detector for imaging.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Sapphire board 12 ... Infrared ray detection element 14 ... Cold door aperture 16 ... Opening 18.18 '... Light-shielding barrier

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor ▲ Hiro ▼ Ta Koji 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Hiroyuki Tsuchida 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Stock In-company (56) References JP-A-2-165672 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 27/14-27/148 H01L 29/762-29/768

Claims (4)

(57) [Claims] 1. An imaging infrared detector comprising a plurality of infrared detecting elements (12) arranged at a predetermined pitch on a substrate (10), an intermediate point between two adjacent infrared detecting elements (12). Shielding barriers (18, 1
8 ') a set only, the light-shielding barrier (18) is the infrared detection
An infrared detector for imaging, comprising the same material as the output element (12) . 2. An infrared detector for imaging according to claim 1 , wherein a cold aperture is provided in an array area of said infrared detecting elements (12) so as to restrict incidence of background light to each of said infrared detecting elements (12). (14), wherein the light-shielding barrier (18) provides a bearing surface for the cold door aperture (14). 3. An infrared detector for imaging according to claim 1, wherein a cold aperture is provided in an array area of said infrared detecting elements (12) to restrict incidence of background light to each of said infrared detecting elements (12). (14), wherein the light shielding barrier (18 ') is formed integrally with the cold door aperture (14). 4. A method of manufacturing an infrared detector for imaging comprising a plurality of infrared detecting elements (12) arranged at a predetermined arrangement pitch on a substrate (10), the method comprising detecting infrared light on the substrate (10). An element material layer (20) is formed, and the infrared detection element (12) is formed on the infrared detection element material layer (20).
The first resist (22) is applied corresponding to the arrangement position of (1), and the intermediate position between the two adjacent arrangement positions along the transverse direction and at least over the size of the infrared detecting element (12). A second resist (24) is applied to the first and second resists (22,
The infrared detecting element material other than the application point of 24) is removed to form an infrared detecting element (12) at a predetermined arrangement pitch, and a light shielding barrier (18) is provided at an intermediate point between two adjacent infrared detecting elements (12). ) And then the first
And removing the second resist (22, 24).