Micromechanical accelerometer with plate-like semiconductor wafers

US5614742A · kind A · utility

Assignee

• LITEF GmbH · DE

Inventors

• Thomas Gessner · Plymouth, US
• Martin Hafen · Colmar, FR
• Eberhard Handrich · Kirchzarten, DE
• Peter Leinfelder · Ehrenkirchen, DE
• Bruno Ryrko · Denzlingen, DE
• Egbert Vetter · Gelenau, DE
• Maik Wiemer · Limbach-Oberfrohna, DE

Key dates

• Filing date: Jan 2, 1996
• Grant date: Mar 25, 1997
• Expiry date: Jan 2, 2016

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S148/012
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A high precision micromechanical accelerometer comprises a layered structure of five (5) semiconductor wafers insulated from one another by thin oxide layers. The accelerometer is formed by first connecting a coverplate and a baseplate to associated insulating plates. Counter-electrodes, produced by anisotropic etching from the respective insulating plates, are fixed to the coverplate and the baseplate respectively. The counter-electrodes are contactable through the cover or baseplate via contact windows. A central wafer contains a unilaterally linked mass (pendulum) that is also produced by anisotropic etching and which serves as a movable central electrode of a differential capacitor. The layered structure is hermetically sealed by semiconductor fusion bonding. A stepped gradation from the top is formed at a wafer edge region for attaching contact pads to individual wafers to permit electrical contacting of individual wafers. The invention permits fabrication of a .mu.B device characterized by extremely small leakage capacitances and high temperature stability.