Technical method of infrared detector indium bump

Abstract

The invention provides a technical method of an infrared detector indium bump. The method comprises spin-coating two layers of photoresist on a chip in a superposing manner, and further comprises the following steps: firstly, spin-coating a layer of negative photoresist on the chip, and then spin-coating a layer of inversion photoresist on the negative photoresist; through a masking plate exposure and masking plate-free exposure, enabling the contours of the sections of the upper half portions of the two layers of photoresist on the chip to be trapezoidal and the contours of the sections of the lower half portions to be inverted-trapezoidal; and performing indium membrane precipitation, wherein an indium precipitation window is not obviously reduced and an indium bump is platform-shaped so that subsequent preparation is facilitated. By means of the method provided by the invention, the technical problem of preparing a flat-top indium bump on the chip is solved, and good effects of easy preparation, low cost and facilitated combination with external equipment are achieved.

Description

technical field [0001] The invention belongs to the technical field of detectors, and in particular, provides a process method for an indium column of an infrared detector. Background technique [0002] The photosensitive part of the infrared detector is connected with the readout circuit part through an indium column. Under the requirement of increasing pixel density, the distance between pixels is getting smaller and smaller, and the diameter of the indium column is also reduced, but its height cannot be reduced. When the diameter is reduced but the height remains the same, the indium column is easy to grow into a conical shape. This is because during the indium deposition process, the indium on the photoresist mask will not only grow thicker, but also grow laterally, resulting in the deposition of indium. The window of the pillar shrinks, so that the deposited indium pillar becomes smaller in diameter and finally becomes tapered. Generally, when the growth height of ind...

AI Technical Summary

Problems solved by technology

However, due to the unevenness of both the photosensitive material and the readout circuit, reducing the height of the indium column will cause the concave position of the photosensitive material or the readout circuit to be inaccessible, resulting in the problem of soldering failure.

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