Electrostatic Force Rebalance Pendulum Silicon Micro Accelerometer Sensitive Structure and Manufacturing Method

Abstract

The sensitive structure of the electrostatic force rebalanced pendulum silicon micro accelerometer is the upper and lower glass plates, and the middle is the sensitive mass block of the monocrystalline silicon pendulum structure. The three are connected together by bonding. The double flexible beams of the crystalline silicon sensitive mass are arranged opposite to the lead-out lines of the electrodes. In addition, in order to further reduce the influence of temperature on the monocrystalline silicon pendulum plate, the bonding area is reduced in the design, instead of the overall bonding, three small pieces of bonding are used to ensure that the bonding area of ​​the upper and lower glass plates is completely Consistent, and further reduce the temperature coefficient caused by thermal stress; the manufacturing method of the above-mentioned sensitive structure includes the manufacturing of single crystal silicon pendulum plate and the manufacturing of upper and lower glass cover plates. The invention can reduce the temperature coefficient of the instrument and improve the temperature repeatability, thereby improving the resolution and sensitivity of the silicon micro accelerometer and meeting the requirements of inertial guidance systems such as missiles.

Description

Technical field [0001] The invention relates to a sensitive structure and a manufacturing method of a silicon micro-accelerometer, in particular to a sensitive structure and a manufacturing method of an electrostatic force rebalancing pendulum silicon micro-accelerometer. Background technique [0002] Silicon accelerometer is an important mechanical sensor widely used in control, navigation, monitoring and other systems. In 1977, Stanford University in the United States first manufactured an open-loop silicon accelerometer using micromachining technology, but the performance of this early-produced silicon accelerometer was relatively poor, specifically manifested in small dynamic range, low resolution, bias and The stability of the scale factor is relatively poor, which cannot meet the precision requirements of the inertial instrument. With the further development of semiconductor technology, especially the development of MEMS, the closed-loop force balance silicon accelero...

AI Technical Summary

Problems solved by technology

Although the temperature coefficient ratio and temperature repeatability of this sensitive structure have been greatly improved, the manufacturing process of the three-layer microstructure cannot be completely symmetrical. This asymmetry still brings the temperature coefficient when the ambient temperature changes relatively When it is large, there is deformation, which leads to poor temperature characteristics of the instrument and poor temperature repeatability

[0006] In addition, the silicon pendulum is etched from top to bottom at the same time, which requires double-sided engraving. Many processes have strict requirements and there are errors

As the corrosion progresses, the concentration of the corrosion solution changes, which makes the corrosion rate unstable and the symmetry of the upper and lower gaps is affected.

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