Single anchor supporting-type double axis silicon micro resonant accelerometer

Abstract

The invention discloses a single anchor supporting-type double axis silicon micro resonant accelerometer, which comprises a lower-layer glass substrate, a lead layer, a bonding layer and an upper-layer silicon structure layer, wherein the bottom layer is the glass substrate; metal is sputtered on the upper surface of the glass substrate as the lead layer; the bonding layer is arranged on the glass substrate and the lead layer, and through the bonding layer, the silicon structure layer is suspended above the glass substrate; the movable structure of the entire upper-layer silicon structure layer is supported by the only anchor; the upper-layer silicon structure layer comprises a fixed supporting frame and four upper-layer silicon micromechanical substructures, and the upper-layer silicon micromechanical substructures are arranged sequentially in a counter-clockwise direction; and the first upper-layer silicon micromechanical substructure and the third upper-layer silicon micromechanical substructure, and the second upper-layer silicon micromechanical substructure and the fourth upper-layer silicon micromechanical substructure form groups of accelerometer measurement modules respectively. Influences brought by mismatch between material properties of the substrate material and the silicon material can be effectively restrained, residual stress generated in the case of bonding and thermal stress in the case of environmental changes can be eliminated, and decoupling between two orthogonal directions is realized.

Description

technical field [0001] The invention relates to the technical fields of micro-electromechanical systems (MEMS) and micro-inertial measurement, in particular to a single-anchor point-supported biaxial silicon micro-resonance accelerometer. Background technique [0002] Since the 1980s, the development of micro-electromechanical systems and micro-manufacturing technology has promoted the development of micro-inertial technology and micro-inertial instruments, leading to the generation of a new generation of accelerometers and gyroscopes. Micro-inertial instruments are mostly manufactured by semiconductor processing technology, with small size, light weight and low power consumption. Using silicon as a processing material and using a processing technology compatible with the manufacturing process of microelectronic integrated circuits can integrate the sensitive meter and signal processing circuit of silicon micro inertial devices on one chip, thereby realizing mass production ...

AI Technical Summary

Problems solved by technology

[0004] At present, the existing biaxial silicon microresonant accelerometers are generally composed of resonators, mass blocks and glass substrates. The four resonators are of the same size, and the movable structure is supported by multiple anchor points. It is possible to make the resonator processing completely symmetrical, so the influence of material property mismatch and ambient temperature on the device is highlighted

Silicon microresonant accelerometers are widely used in anchor point bonding during processing. During anchor point bonding, the ambient temperature must be controlled at 400°C, and the structural layer material (silicon) and substrate material (glass) are heated to about 400°C. Due to the difference in thermal expansion coefficient and thermal conductivity coefficient between silicon and glass, when there are multiple anchor points, the mismatch of material properties between silicon and glass between any two anchor points will cause the silicon material to be unable to freely expand with heat and contract with cold , when the structure is cooled to room temperature after bonding, a large residual stress will be generated, and the residual stress will affect the stability of the resonant frequency by affecting the mechanical properties of the resonator; in addition, in the use environment, when the temperature changes , due to the mismatch of material properties, the multi-anchor silicon microresonator accelerometer will also generate thermal stress, resulting in a drift of the resonant frequency, making the resonator highly temperature sensitive, and causing the resonator frequency and quality factor The change

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