Wafer manufacturing process flow of high-performance MEMS inertial sensor

Abstract

The invention discloses a wafer manufacturing process flow of an MEMS inertial sensor, which comprises the following steps: providing a first substrate with a top plane and a bottom plane, and arranging an oxide layer below the bottom plane; providing a second substrate having an upper flat surface; etching a portion of the second substrate from the upper flat surface to form a plurality of protrusions and a shallow cavity, each protrusion having an upper flat surface; bonding a top plane of the first substrate to an upper flat surfaces of the protrusions to form an anchoring portion; etchingoff the oxide layer at a certain position of the first substrate; etching a portion of the first substrate from the bottom surface and / or the top surface to a total thickness of the first substrate toform a sensitive structure having a freely rotatable structure. Icon alignment is not needed during silicon-silicon bonding, so that the bonding process is simple, the thickness of the formed beam isequal to that of the mass block, no error is generated, and better structural symmetry is achieved.

Description

technical field [0001] The invention relates to a manufacturing process of an inertial sensor, in particular to a wafer manufacturing method of a MEMS inertial sensor. Background technique [0002] A wide variety of applications, especially aerospace applications such as inertial navigation systems, guidance systems and aeronautical data measurement systems, require high performance accelerometers with near microgravity resolution, high sensitivity, high linearity and low bias drift and gyroscope. The resolution of high-performance accelerometers and gyroscopes is limited by the thermomechanical Brownian noise of the sensor, which is determined by the damping coefficient and mass of the structure and the readout electronics. [0003] Fabrication techniques play a crucial role in ensuring simultaneous access to large mass, large capacitance and small damping, as well as achieving microgravity resolution. Previously, many high-performance silicon accelerometers and gyroscope...

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Problems solved by technology

However, the above process requires the first substrate to etch a deep groove, and then perform pattern alignment bonding, which makes the bonding process complicated; and the thickness of the beam is smaller than the thickness of the proof mass, and the center of gravity of the structure is on the upper side, which will make the accelerometer sensor The output symmetry of ±1G produces a certain error

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