Preliminary Results

We have developed CMOS accelerometers by releasing BEOL (Back-End-Of-Line) metal layers using the silicon dioxide as a sacrificial layer. The initial idea is reported in this paper. The sacrificial material (inter-metal oxide) is selectively removed by a wet or gaseous acid agent through open windows in the manufacturing process passivation layer itself that acts as a mask as reported in this paper.

CMOS-MEMS accelerometer. Electromechanical device at the top of the image and conditioning electronics at the bottom of the image.

CMOS-MEMS accelerometer experimental setup. A loudspeaker is used in order to generate vibrations.

Measured signal (top) compared to a comercial accelerometer as reference (bottom)