JPS62139333A - Manufacture of infrared ray detecting element - Google Patents

Abstract

PURPOSE:To avoid any crystalline pollution by a method wherein, when an HgCdTe crystal bonded on the surface of a substrate using a bonding agent is formed into a thin layer to be an infrared ray detecting element, the residual bonding agent exposed to the sides of crystal is removed by O2 plasma etching process. CONSTITUTION:An HgCdTe crystal 3 is bonded on a substrate 1 using epoxy resin bonding agent 2 to be formed into a thin layer with specified thickness using grinding process together with etching process in bromine methanole solution. At this time, any needless residual thick bonding agent 2 around the crystal 3 is removed by O2 plasma etching process i.e. said agent 2 is irradiated with activated O atoms in O2 atmosphere to be removed by etching process. Later, the substrate 1 and the periphery of crystal 3 are coated with a conductor film 6 using a resist 5 as a mask as usual and then the resist 5 is removed to produce an infrared detecting element. Through these procedures, the bonding agent 2 hardly removed by chemical etching process can be removed easily to avoid any crystalline pollution.

Description

[Detailed description of the invention] [Industrial application field] This issue #4 relates to a method for manufacturing an infrared detection element.

[Conventional technology]

Infrared detection elements are made of HgCdTe crystals and electrode terminals bonded onto a substrate, and are broadly classified into photoconductive type detection elements and photovoltaic type detection elements. The photoconductive type detecting element detects resistance change between electrode terminals, and the photovoltaic type detecting element detects HgCd.
Infrared rays are detected as changes in current between pn junctions provided in a Te crystal. In the production of such infrared detecting elements, HgCdTe crystals are bonded onto a substrate with adhesive, and after polishing and etching with a bromine-methanol solution to reduce the thickness to a predetermined thickness, the conductor material, which is the electrode material, is After the layers are formed, etching is performed to form a predetermined element shape. At this time, when the HgCdTe crystal is thinned, a thick layer of adhesive remains exposed on the substrate surrounding the crystal, and the electrode wiring formed later is very likely to break at this portion. Conventionally, this unnecessary adhesive was removed mechanically or etched using a chemical such as sulfuric acid (for example, Japanese Patent Application Laid-Open No. 104523/1983).

[Problem that the invention seeks to solve]

However, mechanical scrubbing causes deterioration of the adhesive strength of the remaining adhesive, and chemical etching is not easy because the luehoxy adhesive originally used has high chemical resistance. There were problems in terms of lack of crystals and contamination of crystals.

The purpose of the present invention is to provide a method for manufacturing an infrared detecting element in which unnecessary adhesive can be easily removed without degrading the adhesive strength of the adhesive remaining on the substrate or contaminating the crystal. be.

[Means for solving problems]

In the method for manufacturing an infrared detection element of the present invention, HgC
After bonding the dTe crystal and making it a thin layer, the HgCdT
This is achieved by performing a step of removing unnecessary adhesive exposed on the substrate by oxygen plasma etching using the e-crystal as a mask.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 (aHe) is a sectional view sequentially showing the manufacturing process of an embodiment of the present invention. First, as shown in FIG. 1(a), HgCdT was applied onto a substrate 1 using an epoxy adhesive 2.
After adhering the e-crystal 3, polishing and etching with bromine methanol solution resulted in Hg as shown in Figure (b).
The CdT@crystal 3 is made thinner. At this time, a thick layer of adhesive 2 remains around the crystal 3, and this layer must be removed because it causes disconnection of the electrode wiring as described above. This layer of adhesive 2 is etched away in an oxygen atmosphere using a plasma etching process. That is,
In FIG. 4E, the epoxy adhesive is etched by irradiating oxygen 8 activated by plasma discharge in an oxygen atmosphere and incinerating the epoxy adhesive with the activated oxygen 8.

Unnecessary adhesive can be easily removed by etching process.
Moreover, unlike mechanical removal, the adhesive strength of the remaining adhesive portion 4 is not reduced. In addition, by appropriately selecting the etching conditions, for example, the oxygen gas pressure can be set to 80 Pa, R
By setting the F power to about 50 W, it is possible to maintain a sufficient etching rate and not cause any damage to the HgCdTe crystal 3.

Following this, in the same way as the normal manufacturing method, the same figure (d)
As shown in the figure (el), a conductor film 6, which is an electrode material, is formed by a so-called lift-off method using a photoresist 5 of a predetermined shape as a mask, and then, as shown in the figure (el), ion milling etching is performed using a photoresist 7 as a mask. The infrared detecting element 9 shown in FIG. Etching can be carried out in the same manner. Sapphire, aluminum nitride, etc. are suitable for the substrate 1, and a laminated layer of Cr and Au, or ij:In, etc. is suitable for the conductor film 6. .

〔Effect of the invention〕

As explained above, according to the present invention, by performing etching with oxygen plasma, unnecessary adhesive on the substrate can be easily removed without damaging the HgCdT@ crystal or the adhesive layer that should remain. It has the effect of being able to be removed.

[Brief explanation of drawings]

FIG. 1 (- to (f) are cross-sectional views showing one embodiment of the present invention in construction order. 1...Substrate, 2, 4...Adhesive, 3...HgCd
Te crystal, 5.7... Photoresist, 6... Conductor layer, 8... Activated oxygen, 9... Infrared detection element. (α) (b) Figure 1

Claims (1)

[Claims] (1) Infrared detection characterized by bonding an HgCdTe crystal onto a substrate and making it a thin layer, and then using the HgCdTe crystal as a mask to remove unnecessary adhesive exposed on the substrate by oxygen plasma etching. Method of manufacturing elements.