CMOS-based tactile sensors using oxide as sacrificial layer

In this work, CMOS-based tactile sensors using oxide as the sacrificial layer was demonstrated. The multiple metal layers and dielectric layers in the backend of CMOS processes were used to fabricate the moveable membrane of capacitive-based tactile sensors. The sensor was fabricated by the commercial 0.35 μm CMOS process and our self-developed post CMOS oxide etching. Three different via designs were proposed to adjust mechanical strength of the membrane electrode. A multivibrator circuit was utilized to decrease the parasitic effect of the capacitive sensors. The tactile sensors with point-type vias showed the best sensitivity of 2.65 Hz/mmHg with the dynamic range 0–388 mmHg.