Si-based Condenser Microphone by Wafer Bonding Technique

摘要

This paper described the fabrication and characteristics of Si-based condenserrnmicrophone that is based on wafer bonding technology and semiconductorrnprocess. The microphone diaphragm and back-plate are defined on 4" silicon. Then, using wafer bonding with adhesive layer in a vacuum environment, the two wafers are bonded together to form a microphone. The microphones are characterized by bonding strength, bonding yield, frequency response and sensitivity. When microphone was finished, it was combined with the amplifier circuit, then examined its frequency response in the anechoic chamber. The device shows frequency response of-45.4 dBV/Pa (-33 dBV/Pa ref. 1 V/Pa) with 25 V bias in 1 kHz. In addition, the bonded sample can stand for dicing process and the dicing yield is above 90%. The bonding strength is above 5 kg/mm~2. A complete microphone chip after dicing which dimension is 2 mmx2 mm x0.6 mm.