Multi-Physics Simulation Platform and Multi-Layer Metal Technology for CMOS-MEMS Accelerometer with Gold Proof Mass

Abstract

This chapter describes technical features and solutions to realize a highly sensitive CMOS-MEMS accelerometer with gold proof mass. The multi-physics simulation platform for designing the CMOS-MEMS device has been developed to understand simultaneously both mechanical and electrical behaviors of MEMS stacked on LSI. MEMS accelerometer fabrication process is established by the multilayer metal technology, which consists of the gold electroplating and the photosensitive polyimide film. The proposed MEMS accelerometers are fabricated and evaluated to verify the effectiveness of the proposed techniques regarding sub-1G MEMS and arrayed MEMS devices. The experimental results show that the Brownian noise of the sub-1G MEMS accelerometer can achieve 780 nG/(Hz) 1/2 and the arrayed MEMS accelerometer has a wide detection, ranging from 1.0 to 20 G. Moreover, using the developed simulation platform, we demonstrate the proposed capacitive CMOS-MEMS accelerometer implemented by the multi-layer metal technology. In conclusion, it is confirmed that the multi-physics simulation platform and the multi-layer metal technology for the CMOS-MEMS device have a potential to realize a nano-gravity sensing technology.

Serpentine spring design technique for high sensitivity MEMS capacitive accelerometer fabricated by gold multi-layer metal technology

“…We have developed a highresolution CMOS-MEMS capacitive accelerometer consisting of a gold proof-mass, spring, fixed electrode, and CMOS LSI. [17][18][19][20][21] When designing a high sensitivity MEMS capacitive accelerometer, there are two key parameters that determine performance: Brownian noise B N and sensitivity S m . First, Brownian noise B N determines the resolution of MEMS capacitive accelerometers.…”