Etching technique of high aspect ratio silicon trenches based on CMOS-MEMS process

Abstract

Etching technique of deep silicon trenches with high aspect ratio is critical in improving integration and accuracy of Micro-Electro-Mechanical Systems(MEMS)sensor array and reducing the cost of it. To fabricate silicon isolation trenches with aspect ratio equaling to 25 μm/0.8 μm,we use and compare three kinds of MEMS process，Reactive Ion Etching(RIE),Bosch,and RIE combined with Bosch,which are all CMOS process compatible and easy to integrate with CMOS ICs.Finally it proves that RIE combined with Bosch process is better than the other two in producing deep trenches with smooth side walls.

Keywords

• cmos-mems process
• high aspect ratio
• deep trench etching
• rie combined with bosch