Thermal hysteresis and voltage shift analysis for differential pressure sensors

Pressure sensors should be capable of measuring pressure accurately and consistently without being disturbed by the temperature environment. With silicon's better thermal material properties, silicon micromachined pressure sensors are mass-produced and widely used. However, a silicon pressure-sensing element has to be packaged and protected. The thermal mismatching between the sensing element and packaging may generate stresses on the transducer of a sensing element and create thermal hysteresis and voltage shift during temperature cycling. The induced thermal stresses can easily deteriorate performance reliability.In this paper, finite element analyses (FEA) and experimental tests were conducted to reduce the thermal stress and thermal hysteresis for differential pressure sensors. With the glass substrate to isolate the stress from plastic housing, the thermal hysteresis can be significantly improved. The die placement and dispense pattern can be also optimized to further improve the thermal hysteresis.