A new concept for LTCC-based pressure sensors

A new type of a LTCC-based pressure sensor was presented. It bases on a new design principle consisting the fully mechanical decoupling of the sensor cell from outer mechanical stress and the pressure connection by integrated micro-channels. The sensor bases on Du Pont's Green Tape 951 system. The 951 system is a fair compromise in comparison to other ceramic materials regarding Young's Modulus and fracture strength. Different post fired resistor pastes for alumina substrates were characterized on LTCC with respect to their R(ind sqr), TCR, N and Gaug Factor. It could be shown that pastes exist which are suited as strain gauges for pressure sensors. Several simulation calculations verified the new design concept. They showed that the decoupling of the sensor cell works properly. Furthermore the sensitivity of different sensor types was simulated. It was shown that there is an easy possibility for the integration of signal conditioning electronics. For the sensor characterization a 12-channel measurement equipment was developed and installed. The sensor behavior is excellent in the tested temperature range. The sensor failures caused by non-linearity and hysteresis are below 0.1 % FS. Entnommen aus <a_href="http://www.fiz-technik.de/db/b_tema.htm" target="_blank">TEMA</a>