Title :
The next generation integrated MEMS and CMOS process on SOI wafers for overdamped accelerometers
Author :
Chen, Thomas D. ; Kelly, T.W. ; Collins, D. ; Berthold, B. ; Brosnihan, T.J. ; Denison, T. ; Kuang, J. ; O´Kane, M. ; Weigold, J.W. ; Bain, D.
Author_Institution :
Micromachined Products Div., Analog Devices, Inc., Cambridge, MA, USA
Abstract :
We developed a MEMS process for the manufacture of accelerometers that combines CMOS processing on SOI wafers. Unit processes for electrical isolation trench fabrication, MEMS structural release, and CMOS foundry compatibility were developed for robustness and reliability. Current-voltage measurements of the isolation trenches show that the trench leakage is < 0.4 nA even at 100V; leakage at the operational voltage of 5V is < 1.63 pA. A "pedestal and bridge" photolithography process was developed to etch away the underlying sacrificial buried oxide to release the MEMS structures. These processes were developed and adapted to ensure the best compatibility with a given 0.6 μm foundry CMOS process for volume production of a particular accelerometer designed for overdamped applications, such as vehicle crash sensing.
Keywords :
CMOS integrated circuits; accelerometers; isolation technology; microsensors; silicon-on-insulator; surface treatment; 0.4 nA; 0.6 micron; 1.63 pA; 100 V; 5 V; CMOS process; MEMS process; SOI wafers; current-voltage measurements; electrical isolation trench fabrication; overdamped accelerometers; photolithography process; sacrificial buried oxide; trench leakage; vehicle crash sensing; Accelerometers; Bridge circuits; CMOS process; Current measurement; Fabrication; Foundries; Manufacturing processes; Micromechanical devices; Robustness; Voltage;
Conference_Titel :
Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05. The 13th International Conference on
Print_ISBN :
0-7803-8994-8
DOI :
10.1109/SENSOR.2005.1497273
