2. How a pressure sensor works
Pressure sensors are a highly interactive combination of complex electronics and robust packaging materials. At the heart of a pressure sensor is the bonded MEMS silicon die, an extremely sensitive structure that includes a small and very thin membrane that bends with applied pressure. This pressure is detected by piezoresistors on top of the membrane and converted, via resistance change, into an electric signal, which is calibrated and evaluated by an application specific integrated circuit (ASIC).
Key to the overall performance of the MEMS silicon die is the pedestal below the silicon, which provides a highly accurate through-hole to guide the pressure transmitting fluid or gas towards the membrane. Glass is the ideal material for these pedestals since it has low electrical and thermal conductivity, high chemical resistance, outstanding structurability, and a coefficient of thermal expansion (CTE) that matches silicon.