Patent ID: 7604749
Filing Date: 2009-10-20
Classification: B81B,B81C

Abstract:
1. A method for preparing a comb drive from an ( 001 ) oriented mono-crystalline substrate having top and bottom surfaces by anisotropic wet etching the substrate from both sides simultaneously, which comprises the steps of: designing a lithography mask having anti-symmetric type comb-drive mask features relating to both rotor teeth and stator teeth and shifts of said mask features for alternately detaching comb teeth; applying the lithography mask by means of lithography and creating an etch mask directly on a micromachined layer or an intermediate layer on each of the top and bottom surfaces of the ( simultaneously anisotropically wet etching the micromachined layer from both sides of the substrate to form alternately detached comb-drive teeth having a vertically anti-symmetric diagonal cross-section where a single tooth is created from both top surface and bottom surface etch mask features; and releasing the anti-symmetric comb-drive teeth by removing the etch mask or intermediation layer, wherein no preceding or succeeding dry etching of said substrate is required.