Hot air speed and air direction sensor based on thinning process and manufacturing method thereof

Abstract

The invention provides a wafer level packaged hot air speed and air direction sensor realized by adopting a silicon substrate thinning process technology and a manufacturing method thereof. In a sensor chip, a heating element and a heat-sensitive temperature measuring element are manufactured by adopting a CMOS (Complementary Metal-Oxide-Semiconductor Transistor) process; a heat insulation groovewith the depth of 50 microns is formed between the heating element and the heat-sensitive temperature measuring element by adopting a dry etching process, so that transverse heat conduction effects between the heating element and the heat-sensitive temperature measuring element are reduced; a silicon substrate of a sensing chip is thinned by using a thinning process until the thickness of the silicon substrate is 80-100 microns, so that the heat conduction and the heat capacity of the substrate of the chip are lowered; and a ceramic substrate is attached to the back face of a thinned silicon chip to protect the silicon chip and sense the changes of the air speed and the air direction of the ambient temperature. By adopting the air speed and air direction sensor, wafer package is realized,the heat conduction loss of the silicon substrate and the heat capacity of the sensor chip are greatly lowered, and a large output signal and shorter response time can be obtained under low power consumption.

Description

technical field [0001] The invention relates to a wafer-level packaged thermal wind speed and direction sensor realized by silicon substrate thinning process technology. The sensor chip is prepared by standard CMOS integrated circuit technology, and especially relates to a low-power integrated wind speed sensor based on ceramic packaging. Wind direction sensor and preparation method thereof. Background technique [0002] In the design of CMOS integrated wind speed and direction sensors, packaging has always been a technical bottleneck hindering its development. On the one hand, the encapsulation material is required to have good thermal conductivity and to protect the sensor, and the impact of the encapsulation material on the sensitivity, reliability and price of the sensor needs to be considered in the design, which limits the sensor’s own encapsulation. Design freedom. On the other hand, the thermal flow sensor requires the sensitive part of the sensor to be exposed to ...

AI Technical Summary

Problems solved by technology

As a result, silicon wafers are easily subject to various contaminations, resulting in unstable performance and even damage.

If a ceramic substrate with high thermal conductivity is used, and the silicon chip of the sensor is packaged by flip-chip packaging or thermally conductive adhesive, the above contradictions can be better avoided, but the heat generated by the sensor after packaging is extremely large. Part of it is dissipated from the silicon-based substrate in the form of heat conduction, and only a small part is heat-exchanged with the outside air through the ceramic, which greatly reduces the amplitude of the output sensitive signal, and the sensitive signal can be improved by increasing the power consumption of the sensor. amplitude, but it causes a large power consumption of the entire sensor system

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