METHOD OF ETCHING COMB ELECTRODES BY SELF-ALIGNMENT

摘要

A self-aligned comb electrode etching method is provided to decrease an alignment error between upper and lower structures of a MEMS(Micro Electro-Mechanical System) structure and to precisely form a gap between comb electrodes. A method for etching a fixed comb electrode formed on a first silicon layer(401) of an SOI(Silicon-On-Insulator) substrate(400) and a drive comb electrode formed on a second silicon layer(403) of the substrate includes steps of: forming a first mask on the part of the first silicon layer where the fixed comb electrode is formed, a second mask on the position where the drive comb electrode is formed, and an oxidization preventing layer(S) on a region correspondent to the fixed comb electrode part of the second silicon layer; etching the first silicon layer exposed to the second mask to a predetermined depth; removing the second mask, etching the first silicon layer exposed to the first mask, and leaving a first part of the first silicon layer of the predetermined height on the drive comb electrode part; etching an insulating layer(402) of the substrate exposed to the first mask and the first part; etching the second silicon layer exposed to the first mask and the first part; removing the first mask and forming a silicon oxide layer on the exposed silicon layer; removing the oxidization preventing layer and etching the silicon layer formed under the oxidization preventing layer; and removing the silicon oxide layer.