Micromechanical Accelerometer and Method for the Production Thereof

摘要

The high-precision, micromechanical accelerometer is produced as a layered structure made from, in particular, five semiconductor wafers which are insulated with respect to one another by thin semiconductor material oxide layers. The cover plate (1) and baseplate (5) are firstly connected to an assigned insulating plate (2 and 4, respectively) by bonding. Subsequently, counterelectrodes (6, 7) which are fixed on the cover plate and baseplate, respectively, and can be contacted via contact windows (10 and 11, respectively) by the cover plate and baseplate, respectively, are produced from the respective insulating plate by anisotropic etching. A middle wafer (3) contains the unilaterally pivoted mass (14) (pendulum), which is likewise produced by anisotropic etching, and serves at the same time as a movable middle electrode of the differential capacitor. The five-layer structure is hermetically sealed by semiconductor fusion bonding, for example in a vacuum. Electrical contacting of the individual wafer layers is possible from the topside owing to the fact that contact pads (17-21) can be attached for each individual wafer by stepping an edge region of the individual wafers in a staircase fashion. A microaccelerometer according to the invention is distinguished chiefly by extremely low stray capacitances and by high temperature stability.