Micromechanical pressure sensors have been established on the market for many years due to the excellent mechanical properties of monocrystalline silicon. The CiS Research Institute developed a media-resistant version of its miniaturised piezoresistive pressure sensor.
A design with two identical silicon-based absolute pressure sensors enables the simultaneous measurement of differential pressure and process pressure in aggressive media. This solution has the advantage that a very small and compact design can be realised. The approach pursued by the CiS Research Institute uses miniaturised pressure sensors which can be applied to carrier materials such as silicon or ceramics by means of flip-chip technologies. By means of passivation processes adapted to the desired application (ALD, Parylene, etc.), the pressure sensors are available in a media-resistant design. The developed assembly technologies with media-resistant and hermetically sealed encapsulation are optimised with regard to long-term stability and media resistance. The overall assembly is calibrated and contains two ASICs for evaluation of the Wheatstone measuring bridge. Both an analogue and a digital signal (I2C) are output.
Target applications can be found in the chemical and large-scale industry, in the automotive sector, in medical technology and research.
The research and development work described above is funded by the Federal Ministry of Economics and Energy (BMWi) in the research project “Flip-Chip Assembly for the Construction of Pressure Sensor Flip-Chip DDS” (Flip-Chip-DDS).