Micro-mechanical acceleration sensor with anti-stiction feature

摘要

The micro-mechanical acceleration sensor (1) has a silicon substrate base (2) whose upper surface (3) has an insulating oxide layer (4) and a cavity (5) of depth a few tens of micrometres which is excavated by photolithographic etching. A first contact plate (7) provides an electrical connection to a number of finger-shaped capacitor elements (9a to 9e) which run parallel to the surface (3) and these are interleaved by the similar capacitor elements (10a to 10d) extending from the seismic mass (11). The mass (11) is supported by the cantilever deflection arms (12a to 12e) and the collective assembly including the contact plate (8) forms the responding element of a variable capacitor incorporated in the same chip as the acceleration evaluation module (not shown).