Patent ID: 8304846
Filing Date: 2012-11-06
Classification: H01L,H04R

Abstract:
1. A process of forming an integrated circuit including a capacitive microphone, comprising: providing a substrate, said substrate including a semiconductor region which extends to a surface of said substrate; forming a dielectric support layer at said surface of said substrate; forming access holes through said dielectric support layer; forming a fixed plate of said capacitive microphone on said dielectric support layer; forming a capacitor cavity sacrificial layer on said fixed plate, said capacitor cavity sacrificial layer containing a sacrificial material; forming a permeable membrane on said capacitor cavity sacrificial layer; removing said sacrificial material from said capacitor cavity sacrificial layer, such that a space separates said permeable membrane from said fixed plate; and performing a cavity formation process so as to form a back side cavity in said substrate by providing etchants through said permeable membrane and through said access holes to said substrate, such that said back side cavity is connected through said access holes to said space between said permeable membrane and said fixed plate, and such that a bottom of said cavity is located in said substrate.