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 multi-layer metal technology, which consists of the gold electroplating and the photo-sensitive 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.
Part of the book: Novel Metal Electrodeposition and the Recent Application