JPH041294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing an infrared detector used for earth sensors and the like.

Conventional structure and problems Thermal infrared detectors such as pyroelectric type absorb infrared rays, and the resulting temperature rise causes the generation of electric charges (pyroelectric effect) or changes in resistance (detectors such as thermistors). We are using. Therefore, in order to effectively utilize the incident infrared rays, it is necessary to reduce the heat capacity of the detector and facilitate the temperature rise of the detector.

Conventionally, as shown in FIG. 1, an insulator 11 is made hollow to reduce the heat capacity of the detector.
A thermal infrared detector (for example, a lead titanate pyroelectric detector) 12 having a thickness of several to several hundred micrometers is adhered to (for example, silicon whose upper surface 111 is oxidized) using an insulating adhesive 13. A common electrode 121 made of aluminum or the like is provided on the back side of the detector, and is taken out to the outside through a conductive adhesive 122. The electrode on the infrared incident surface of the linear array detector is, for example, a Ni-Cr electrode 123 that also serves as infrared absorption, separating each detection element. The electrodes of each detection element are taken out using a shift register (not shown) or a buffer (not shown) for sequentially scanning and reading out an electrode 124 made of aluminum or gold that reflects infrared rays using a bonding line 125. via or directly to the outside.

In such a conventional structure, bonding wire 1
25 is essential, but in this case bonding with the electrode 124 of the detection element is a problem; if the thickness of the detection element is thin, the detection element will be destroyed if sufficient bonding strength is attempted with an ultrasonic bonder. This resulted in a disadvantage of poor yield.

Purpose of the Invention The present invention solves these drawbacks, and provides a linear array infrared detector in which a sufficiently strong bonding can be achieved with less damage to the detection element, and electrodes on both sides of the element can be taken out from the same surface. The purpose is to obtain.

Structure of the Invention The present invention involves bonding the top surface of an infrared detection element and a support base so that they are on the same plane, taking out the signal electrode from the detection element by vapor deposition, etc., and forming the common electrode on the back side using conductive adhesive, vapor deposition, etc. This is a method for manufacturing an infrared detector in which the bonding wire is drawn out on a flat surface and taken out by a bonding electrode provided on a support base that is stronger than the detection element.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows the structure of an infrared detector according to the present invention and a method of manufacturing the same. As shown in FIG. 1A, a hole 211 is first formed in the silicon substrate 21 by anisotropic etching using a silicon oxide film as a mask. This hole 211 does not necessarily have to be penetrating.
Next, anisotropic etching is performed so that the width and length of the infrared detecting element can be accommodated, and the depth is the thickness desired for the infrared detecting element, thereby forming a stepped portion 212 as shown by the dotted line. do.

An oxide film 213 is formed on the surface of the silicon support base 21 thus produced, as shown in FIG. Step portion 212 of this silicon support stand 21
A thick detecting element 22 with a back electrode 221 that has been polished on one side in advance is adhered to the inside using an insulating adhesive 23 and a conductive adhesive 24. Next, as shown in FIG. 3C, the upper surface of the detection element 22 is polished until it is at the same height as the silicon support base 21, so that the surfaces are flush with each other. As shown in FIG.
For example, Ni-Cr may be used as the signal extraction electrode 2.
As 23, aluminum or gold that reflects infrared rays is deposited, and a bonding wire 224 is taken out from the bonding electrode 214 on the silicon support 21. Similarly, an electrode terminal 225 is provided on the silicon support 21, and the back electrode 221 of the detector element is connected to the bonding wire 226 through the conductive adhesive 24.
Take it out.

By doing so, the output of the rear common electrode 221 of the detection element can be taken out from the same upper surface as the signal electrode bonding electrode 214 using the bonding electrode terminal 225 via the conductive adhesive 24.

Furthermore, as the support base 21, it goes without saying that ceramic or other insulators may be used in place of the silicon substrate.

Effects of the Invention As described above, in the present invention, an infrared detection element is bonded to a support base having a stepped portion corresponding to the thickness of the infrared detection element, and the top surface of the detection element and the top surface of the support base are on the same plane. Adjust by polishing, etc., and attach conductive adhesive to the signal electrode of the detection element, the back common electrode, and its extraction electrode. This infrared detector is formed by vapor deposition, etc., and this extraction electrode is extended to a bonding electrode formed on a support base, and the bonding wire is taken out from this bonding electrode.The detection element and support base are on the same plane. Therefore, no unevenness occurs on the deposited electrode, so there is no risk of wire breakage. In addition, the bonding strength is increased by not taking out the bonding wires directly from each element of the detector, but from the same top surface on a support base that is thicker and stronger than the detector.
Yield is improved.

An infrared detector having such a configuration is particularly effective as a high-density linear array infrared detector.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a conventional linear array infrared detector, and FIG. 2 is for explaining the manufacturing method and configuration of a linear array infrared detector as an example of the infrared detector according to the present invention. In the figure, A, B and C are cross-sectional views showing the manufacturing process,
D is a plan view. 21...Silicon substrate, 211...Processed shape,
212... Stepped shape, 22... Infrared detection element, 23... Insulating adhesive, 24... Conductive adhesive, 213... Oxide film, 214... Bonding electrode, 221... Back electrode, 222... Infrared absorption electrode, 223... Signal extraction electrode, 224... Bonding wire, 225... Back electrode terminal, 226
...bonding wire.

Claims (1)

[Scope of Claims] 1. In a method for manufacturing an infrared detector that detects infrared rays by an infrared detecting element in which an infrared absorbing electrode group is formed on the upper surface and a rear common electrode is formed on the lower surface, first, the infrared detecting element is A back common electrode is formed on the lower surface of the infrared detecting element, and a back common electrode of the infrared detecting element is formed on one end side of the support having a step portion corresponding to the thickness of the infrared detecting element and larger than the size of the infrared detecting element. It is mounted with a conductive material that is electrically connected to the electrode, and is adhered to the other end of the support with an insulating material that is electrically insulated from the rear common electrode of the infrared detection element. Adjust by polishing so that the upper surface of the detection element and the support base are on the same plane, and form an infrared absorbing electrode group on the upper surface of the infrared detection element, and a bonding electrode group formed on the upper surface of the support base. , the infrared absorbing electrode group formed on the upper surface of the infrared detecting element is electrically connected to the infrared absorbing electrode group formed on the upper surface of the infrared detecting element through a first signal readout electrode formed by vapor deposition; The electrode and the conductive material exposed on the upper surface of the infrared detection element are electrically connected by a second signal readout electrode by vapor deposition, and then the bonding electrode group and the bonding common electrode are connected. A method of manufacturing an infrared detector in which a bonding wire is formed on the infrared detector.