Comb teeth type body silicon working microchemical accelerometer

Abstract

The structure of comb tooth type silicon processing micromachinery accelerometer includes the tooth comb formed by means of body processing, sensing quality element formed from several groups of moving teeth and folded beam group fixed tooth biased fixed tooth and substrate, and its circuit includes the portions of microcapacitor detection and force feedback servocircuit, etc. Said invention can develope the face-processed comb tooth structure into body-processed comb tooth sturcture by means of fixed tooth biased structure, and can increase detection and thrust capacitance so as to greatly raise its resolution and accuracy. Besides, in its preamplifier low input impedance circuit is used and in closed loop feedback thrust the differential D.C. voltage mode is used, so that it can make instrument possess high accuracy.

Description

technical field [0001] The invention relates to a comb-tooth type body silicon processing micromachine accelerometer, which belongs to the field of microelectromechanical systems. Background technique [0002] Micromachined accelerometers have been developed in recent years. The ADXL50 of American AD Company is the most representative micromachined accelerometer on the market. AD company started the research of comb-tooth capacitive accelerometer in 1989. In 1990, it cooperated with German Seimens company to develop its electronic measurement circuit. It was put into production in 1993 and has now formed a series of products. This force-balanced accelerometer is made of surface processing technology, and the sensitive axis is parallel to the substrate. figure 1 A schematic diagram of its structure. The proof mass is "H" shaped. Four thin beams with a width of 2 μm in the shape of an "H" fix the detection mass on the substrate, and the detection mass can freely move along...

AI Technical Summary

Problems solved by technology

However, due to the small measurement capacitance of the comb-tooth structure obtained by surface processing, it affects the further improvement of the resolution and accuracy of the comb-tooth micromechanical sensor.

Replacing surface processing with bulk silicon processing is an effective way to overcome the above disadvantages. However, for the comb structure of body processing, due to the small bonding surface of the fixed teeth uniform configuration structure, and the thicker movable sheet and the increased mass of the sensitive quality of bulk silicon processing, the process After the running water came down, the bonded fixed teeth fell off seriously, and the resistance between the fixed teeth measured by the probe station was very large, which was mainly due to insufficient bonding strength.

In addition, the bonding contact resistance also increases

The Chinese patent (Application No.: 01141718.8) titled "Cab Teeth Offset Micromechanical Structure for Bulk Silicon Machining with Fixed Teeth" proposes a comb-teeth micromechanical structure for Bulk Silicon Machining with fixed teeth offset, but the structure The gap between the moving piece and the substrate is small, and it is easy to be stuck during work, making the work abnormal

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