Wafer-level packaging structure for improving response rate of thermopile infrared detector

Abstract

The invention provides a wafer-level packaging structure for improving a response rate of a thermopile infrared detector. The wafer-level packaging structure comprises an infrared detector and a bearing base plate for bearing the infrared detector; the infrared detector comprises a silicon substrate, a floating film, a cavity structure and a thermopile structure, wherein the cavity structure is formed in the silicon substrate; the thermopile structure is formed in the floating film; one end of the thermopile structure is a hot end; the other end of the thermopile is a cold end; a lead-wire electrode is led out on the floating film; a welding flux convex point is formed on the lead-wire electrode; and the infrared detector is buckled and stacked on the bearing base plate in an inverted manner. The wafer-level packaging structure is improved as follows: an infrared antireflection film is grown on the back surface of the silicon substrate of the infrared detector, and an infrared reflective film is arranged on the surface of the bearing plate directly opposite to the floating film below the cavity structure. The wafer-level packaging structure is further improved as follows: the infrared antireflection film is a graphical infrared antireflection film which is covered on the back surface of the silicon substrate except a corresponding area of the back surface of the silicon substrate above the cold end. The wafer-level packaging structure is used for improving the response rate of the infrared detector.

Description

technical field [0001] The invention relates to a microelectronic packaging structure, in particular to a wafer-level packaging structure of a thermopile infrared detector. Background technique [0002] Infrared detectors are one of the most critical components in an infrared system. The thermopile infrared detector is an uncooled infrared detector developed earlier. Its working principle is based on the Seebeck effect, in which a temperature difference between two different electrical conductors or semiconductor materials results in a voltage difference between the two materials. Because thermopile infrared detectors have the advantages of small size, can work at room temperature, wide-spectrum infrared radiation response, can detect constant radiation, and low manufacturing cost, they are widely used in safety monitoring, medical treatment, life detection, etc. [0003] At present, the thermopile structure generally adopts a thin film structure to achieve a good heat ins...

AI Technical Summary

Problems solved by technology

[0005] However, since the silicon base material has a certain selectivity to the infrared band, and the transmittance of the original silicon base is not high, there is an infrared reflection phenomenon on the silicon surface, which will cause the infrared radiation energy to attenuate

In addition, the material of the suspension film 3 has a low absorption rate of infrared rays, causing secondary attenuation of infrared radiation energy, which limits the wavelength of the detector and lowers the responsivity.

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