Capacitive pressure sensor in post-processing on LTCC substrates

A capacitive pressure sensor was realized by means of a post-processing step on a low temperature co-fired ceramics (LTCC) substrate. The new sensor fabrication technology allows for integration of the sensor with interface circuitry and possibly also wireless transmission circuits on LTCC substrates to realize a truly autonomous sensor unit. A special feature of this sensor technology is the flush surface. The article describes the design considerations, and compares experimental data to the theoretical design. Special point of attention is the long-term behaviour of the soldering joint. Various design variants have been evaluated considering reproducibility and creep behaviour.