Multi Heat-Sink CMOS-BEOL Integrated MEMS Pirani Gauge for Vacuum Detection in Packaged Microsensors

A multi-heat sink based MEMS Pirani gauge integrated in the back-end-of-line (BEOL) CMOS layers is designed and developed. The sandwiched heater line (SiO
2
/M2/SiO
2
) is designed in a meander configuration for improved heating efficiency. Multi heat-sink based design offers improved sensitivity and the thinner heater line offers reduced solid conduction losses and a lower detection limit. In a fully monolithically integrable process, the given gauge can be employed to detect vacuum levels from 4.6 Pa to 10
⁶
Pa. Experimental results agree with the simulated response with a maximum error of 0.16 %. Moreover, the successive measurements on the same device show a maximum error of 0.026 %, thereby indicating excellent repeatability.