METHOD OF TURNING CONDENSER MICROPHONE INTO ELECTRET, ELECTRET-TURNING DEVICE AND METHOD OF PRODUCING CONDENSER MICROPHONE USING THIS

摘要

A novel electret-turning technology for a silicon microphone capable of easily turning the dielectric film of a condenser microphone formed by micro-processing a silicon substrate into electret, and accommodating variations in microphone sensitivity caused by changes in production and component characteristics. A silicon microphone chip is completed, which is then mounted on a mounting substrate, and as it is kept mounted, each one of dielectric films in the silicon microphone chip is individually turned into electret by corona discharge by one needle electrode (51). A plurality of times of electret-turning operations, that is, a second electret-turning quantity and thereafter, are properly determined based on actual measurement results of microphone sensitivity, whereby dielectric films are accurately and efficiently turned into electret.