Patent ID: 6212056
Filing Date: 2001-04-03
Classification: H01G

Abstract:
A variable capacitor comprisinga first wafer having a main planar surface,a single-layer flexible membrane formed integral with said wafer and mechanically supported by said wafer only along the entire periphery of said membrane, the surface of said membrane comprising a portion of said main planar surface,a first metal capacitor plate on the surface of said flexible membrane,a second wafer having a main planar surface,a well in the surface of said second wafer,a second metal capacitor plate in said well,said first and second wafers being bonded together such that the respective main planar surfaces thereof face each other and said first and second capacitor plates are in alignment with each other with an air-gap therebetween,and metal patterns on said first and second wafers respectively connected to said first and second plates to provide bonding pads for electrical connections to said plates,wherein said first wafer comprises single-crystal silicon, the surface of said silicon wafer constituting the main planar surface of said first wafer.