CAPACITIVE MEMS MICROPHONE AND METHOD OF MAKING THE SAME

摘要

The present invention relates to a capacitive MEMS microphone and a manufacturing method thereof, capable of obtaining low surface resistance and low stress through a low temperature process by using metal silicide when manufacturing a membrane and a back plate electrode and limiting the excessive movement of the membrane by inserting a support part between the membrane and a back plate. The manufacturing method of the capacitive MEMS microphone comprises: a first step of etching an upper portion of a silicon substrate; a second step of depositing an insulation film on the etched surface on the silicon substrate; a third step of forming a metal silicide membrane on the insulation film; a fourth step of forming a first sacrificial layer on the membrane; a fifth step of forming the support part on the first sacrificial layer; a sixth step of forming a second sacrificial layer after forming the support part; a seventh step of forming a pattern for dimples on the second sacrificial layer and then depositing an insulation film for dimples; an eighth step of forming a metal silicide back plate on the insulation film for dimples; and a ninth step of forming a back chamber by silicon etching and removing the sacrificial layer to form an air gap. According to the present invention, since metal silicide is used to manufacture the membrane and the back plate, stress can be controlled by a low temperature process of approximately 350C, and the low surface resistance can be obtained. A structure operating as the support part is inserted between the membrane and the back plate to prevent damage and stiction in the membrane.