Cantilever beam acceleration transducer manufactured by micro-machining on single side of single silicon chip and method

Abstract

The invention relates to a cantilever beam acceleration transducer manufactured by micro-machining on a single side of a single silicon chip and a manufacturing method. The acceleration transducer is characterized in that: an accelerometer is manufactured by micro-mechanical single side machining through the single silicon chip, so that stress caused by the bonding process of a plurality of chipsand different materials is avoided. In order to realize a single side-machined cantilever beam sensitive structure, the cantilever beam structure is released by transversely etching the bottom of thecantilever beam by an anisotropic corrosion method after deep structural etching. The structure provides air squeeze-film damping and mechanical overload protection in a sensitive direction, solves the problem of the absence of air squeeze-film damping in the vertical sensitive direction of the conventional structure and prevents parasitic signal interference caused by structural resonance in thevertical direction. The acceleration transducer has the characteristics of particular suitability for measuring a high g value, simple structure, small size of the chip and the like. Simultaneously, a single side process can use low-cost single throwing silicon chips, is suitable for low-cost mass manufacturing and has higher performance and wide application prospects.

Description

technical field [0001] The invention relates to a cantilever beam acceleration sensor and method produced by single-sided micro-machining on a single silicon chip, belonging to the field of silicon micro-mechanical sensors. Background technique [0002] With the continuous development of MEMS technology and the maturity of silicon micromachined processing technology, silicon micromachined acceleration sensors are widely used in different fields due to their low price, high precision and suitability for mass production, such as automotive airbags and robot industries And automation control and other monitoring projects of various movements. At present, acceleration sensors for high-g range detection in high-shock environments are widely used in military, aerospace and other fields. In recent years, with the development of penetrating weapons and the continuous deepening of research on high-explosive shock phenomena, the demand and requirements for high-range acceleration sen...

AI Technical Summary

Problems solved by technology

This type of acceleration sensor mainly has the following two different structures: (1) cantilever beam + mass block structure, for example, [1] Y Ning, Y Loke, G Mckinnon MCKNNON G, Fabrication and characterization of high-g-force, silicon piezoresistive accelerometers, Sensors and Actuators.1995, A48:55-61. (2) cantilever beam structure, for example, [2] J.Dong, X.Li, Y.Wang, D.Lu and S.Ahat, Silicon micromachined high-shock accelerometers with acurved-surface-application structure for over-rang stop protection and free-mode-resonance depression, J.Micromech.Microeng.2002, 12(6): 742-746. The surface micromachined acceleration sensor needs to spend a lot of time in the production process to use KOH solution to thin the silicon wafer in a large area and deep to the expected thickness of the structural beam, which not only prolongs the production cycle, but also (100) silicon wafer back corrosion The formed inclined sidewall occupies a large area, so the chip size after processing is very large (see figure 1 ), and the processed device needs to provide its strength and substrate through silicon-silicon bonding or silicon-glass bonding, which not only increases the complexity of the process, but also increases the production cost, and the acceleration sensor of this bonding structure Its working bandwidth and high-range shock resistance are greatly reduced, and it is difficult to meet the detection requirements of ultra-high g range (>80,000 g).

More importantly, due to the large gap between the cantilever beam and the substrate, this kind of double-sided micromachined sensor does not have enough air pressure film damping in the direction perpendicular to the sensitive direction to suppress the spurious signal interference caused by the structural resonance.

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