Micro-mechanical CMOS (complementary metal oxide semiconductor) thermopile infrared temperature sensor

Abstract

The invention relates to a micro-mechanical CMOS (complementary metal oxide semiconductor) thermopile infrared temperature sensor which is characterized by adopting a bridge type structure and comprising a silicon substrate and a microbridge arranged on the silicon substrate, wherein a thermopile hot end is positioned in the microbridge central area, and a cold end is positioned above a heat sink of the silicon substrate; a sensor photosensitive area of the microbridge central area is suspended above a cavity formed by etching the silicon substrate; the microbridge comprises a support layer, an Al-Si (aluminum-silicon) thermocouple and a passivation layer, wherein the support layer is made from a silicon oxide film and a silicon nitride film which are sequentially arranged from inside to outside, the Al-Si thermocouple is made from the doped polysilicon and an Al film, and the passivation layer is made from silicon nitride; the outer surface of the sensor photosensitive area of the microbridge is provided with an infrared absorption layer; an isolation medium layer is arranged between the doped polysilicon and the Al film; and an etching hole is arranged on the microbridge. The invention has the beneficial effects that: the sensor can be processed and manufactured on a CMOS integrated circuit instead of a factory; the development of a special material and a manufacturing method for the devices is not needed; the method has good generality; large-scale batch production is convenient; and the device cost is low. Moreover, the sensor release is realized by the front photoetching and dry plasma etching technology; and the method has good stability and perfect controllability, and ensures high device yield.

Description

technical field [0001] The invention relates to a micromechanical CMOS thermopile infrared temperature measuring sensor. Background technique [0002] Infrared is a kind of light invisible to human eyes, which is outside the visible light band, and it contains the temperature information of objects. By measuring the infrared radiation of an object, the surface temperature of the object can be measured. Thermocouple (thermopile) infrared temperature sensor is a common infrared temperature sensor, which works on the principle of Seebeck effect. The Seebeck effect refers to the thermocouple composed of two different materials, if there is a temperature difference between the two nodes in a closed loop, an electromotive force will be generated between the two nodes. Early thermopile infrared temperature sensors were obtained by depositing thermocouple materials on plastic or alumina substrates. With the development of MEMS technology, various MEMS infrared temperature sensors...

AI Technical Summary

Problems solved by technology

However, there are still deficiencies: First, the patented thermocouple material uses doped single crystal silicon and Al thin film. Compared with polycrystalline silicon, although single crystal silicon has a high Seebeck coefficient, the cost of the SOI substrate is relatively high, which is not conducive to the further development of the device. cut costs

Secondly, the invention uses wet etching (TMAH or KOH) to etch the silicon substrate, which is difficult to protect the substrate by wet etching, and it is difficult to guarantee the controllability of the corrosion

Images