Thermal wind sensor based on anodic bonding technology and preparation method thereof

Abstract

The invention discloses a wafer level package thermal wind sensor based on an anodic bonding technology which comprises the following steps: step 1, preparation of silicon chips, manufacturing a heating element, a thermal sensing temperature measuring element and an electric extraction pad by utilizing a standard CMOS (complementary metal-oxide-semiconductor transistor) technology, and etching off an oxide layer at the anodic bonding area at the front surface of the silicon chip by utilizing an MEMS (micro electro mechanical systems) dry etching technology, so that a silicon substrate is exposed; step 2, preparation of packaging glass substrate, preparing bosses for anodic bonding by utilizing an anodic bonding technology, and preparing a through hole for electric extraction by utilizing a laser etching technology; step 3, carrying out bonding packaging on the silicon chips and packaged glass substrate by utilizing the anodic bonding technology; step 4, carrying out thinning on the substrate of the silicon chips by utilizing a thinning technology; step 5, sticking and sealing a ceramic sensing substrate on the back face of the pair of thinned chips; and step 6, scribing and finishing the preparation of the sensor. In the whole preparation process of the sensor, the preparation technologies used are compatible with the standard CMOS technology; the postprocessing technology is simple; the frontage protection of the silicon chips for sensing is realized by the packaging anodic bonding technology; the ceramics are basically sticked and sealed to the back face of the thinned silicon chips, on the one hand, the ceramics serve as heat sensitive materials to sense the wind changes in the outside environment, and on the other hand, the ceramics are used for protecting the silicon chips. By the sensor, the wafer level packaging is realized, and the sensor has the characteristics of good compatibility, simple subsequent technology, and low cost.

Description

technical field [0001] The invention relates to a wafer-level packaged thermal wind speed and direction sensor realized by anodic bonding technology, the preparation process is compatible with the standard CMOS process, in particular to a low power consumption integrated wind speed and direction sensor based on glass and ceramic packaging and its Preparation. 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 the measurement environment, and ...

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

Images