Patent ID: 7343661

Claim:
A method for making condenser microphones, comprising: forming a fixed electrode layer structure of a plurality of fixed electrode units; forming a sacrificial layer of a plurality of sacrificial units on one side of the fixed electrode layer structure such that the sacrificial units are aligned with the fixed electrode units, respectively; forming a diaphragm layer structure of a plurality of diaphragm units on the sacrificial layer such that the diaphragm units are aligned with the sacrificial units, respectively; forming a patterned mask layer on an opposite side of the fixed electrode layer structure opposite to the sacrificial layer; forming a plurality of etching channels, each of which extends through the patterned mask layer and the fixed electrode layer structure; removing a portion of the sacrificial layer of each of the sacrificial units by wet etching by passing an etchant into the etching channels so as to form a spacer between a respective one of the fixed electrode units and a respective one of the diaphragm units; and removing the patterned mask layer from the fixed electrode layer structure.