A method for manufacturing an inverted assembly mems chip package structure

Abstract

The invention discloses a preparation method of an MEMS (Micro-electromechanical System) chip packaging structure with inverted assembly. The preparation method comprises the following steps: processing an anchor point structure and a sensitive structure cavity body on a silicon electrode layer of a wafer A and processing an electrode structure in the sensitive structure cavity body; bonding a silicon electrode layer of another wafer B onto a silicon electrode layer on the wafer A by adopting a bonding process; removing a silicon substrate and a silicon-dioxide isolation layer of the wafer B; processing a sensitive structure on the silicon electrode layer of the wafer B; bonding silicon caps onto the sensitive structure on the wafer B; etching in sequence from the back surface of the SOI wafer A to remove the silicon substrate and the silicon-dioxide isolation layer of the SOI wafer A at the area position of a welding disc, exposing the electrode layer of the SOI wafer A at the area of the welding disc, adopting a sputtering mode to process a metal welding disc, and forming an MEMS bare chip; processing a stress release groove in the silicon substrate of the wafer A by adopting a deep-trench etching process; and inverting the chip, fixing the silicon caps to the bottom surface of a ceramic tube shell cavity body, then bonding metal leads to realize electric signal connection between the metal welding disc and ceramic tube shell pins, and finally, sealing a ceramic tube shell by adopting a kovar alloy cover plate. The method disclosed by the invention has the advantages that the packaging process is simple, the packaging cost is not obviously increased and the implementation is easy.

Description

technical field [0001] The invention relates to a MEMS chip packaging structure, which belongs to the technical field of MEMS. Background technique [0002] MEMS (Micro Electro Mechanical System) capacitive sensors have the advantages of small size, light weight, low power consumption, and low cost, and are widely used. The MEMS capacitive sensor realizes the measurement of the corresponding physical quantity to be measured by measuring the capacitance change formed by the tiny sensitive structure. Usually, MEMS sensors need to be packaged in a certain structure to provide the electrical connection, mechanical connection and corresponding chemical environmental protection required by the sensor. [0003] Metal package, plastic package and ceramic package are the three most common packaging forms of MEMS chips. Because ceramic packages have the advantages of good thermal conductivity and air tightness, ceramic packages are most widely used. [0004] The packaging structure...

AI Technical Summary

Problems solved by technology

[0019] Invention patents "MEMS Inertial Sensor Package Structure with Stress Isolation", "Package Structure That Can Reduce Package Stress", "Chip Attach Stress Isolation", "A Pressure Sensor Based on Silicon-Silicon Bonding Isolated Package Stress", " A Thermal Stress Isolation Structure for MEMS Devices" and "A MEMS Device and Its Manufacturing Method" all add a special isolation structure under the existing MEMS bare chip to reduce the impact of packaging stress on chip deformation. The disadvantage of the method is that an additional structural layer is required, thus increasing the overall thickness of the device

Invention patent "Method for Reducing MEMS Chip Packaging Stress Through Back Patterning" Although the etching process is used to process a special graphic structure on the back of the chip, which reduces the contact area between the chip and the package, there are still many parts on the bottom of the chip The problem of fixed connection with the shell, multi-position fixed connection will still generate thermal stress, resulting in deformation of the chip

Its disadvantage is that the packaging cavity and blocking filler need to be specially customized, which increases the processing complexity and cost

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