Silicon-silicon-bonding-based pressure sensor capable of isolating packaging stress

Abstract

The invention discloses a silicon-silicon-bonding-based pressure sensor capable of isolating a packaging stress. The pressure sensor includes a chip layer and a support layer. A lug used for silicon-silicon bonding is etched on the surface of the support layer. Gaps exist between other areas of the support layer and the chip layer. The structure is capable of avoiding too much consideration of material selection (such as a packing substrate of low stress and an adhesive of low stress) so that high-efficiency thermal isolation is realized comparatively easily and larger shock can be resisted and thus the pressure sensor is wider in application occasions.

Description

technical field [0001] The invention belongs to the technical field of silicon micromechanical sensors, and in particular relates to a pressure sensor based on silicon-silicon bonding for isolating package stress. Background technique [0002] A piezoresistive pressure sensor is widely used because it is a DC element and has good linearity. However, piezoresistive sensors are not only sensitive to the stress to be measured, but also to thermal stress. In order to improve the accuracy of the sensor and suppress the thermal zero drift, it is very necessary to reduce the thermal stress caused by the thermal mismatch of the materials during the packaging process. [0003] It is well known that the packaging stress of MEMS sensor chips comes from the thermal expansion coefficient mismatch between packaging materials and silicon chips. The MEMS sensor silicon chip is usually pasted on the substrate with various adhesive materials, and then sintered at a certain temperature to so...

AI Technical Summary

Problems solved by technology

Traditional methods to reduce thermal stress include the following categories: (1) Select substrate materials with low thermal mismatch, that is, alloy materials with a thermal expansion coefficient close to that of silicon, such as Kovar alloy (KOVAR), low-temperature co-fired ceramics, etc.; but this The cost of this method is relatively high

[0004] (2) Use low-stress flexible adhesive materials such as soft silicone; the use of flexible adhesives has the disadvantage of weak bonding strength, and flexible adhesives Not suitable for applications with shear stress

The disadvantage is that the chip area is increased, and a more complicated etching process is required to make the cantilever beam structure

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