A doubly anchored surface micromachined Pirani gauge for vacuum package characterization

This paper presents a surface micromachined Pirani gauge for measuring vacuum pressure inside sealed micro cavities. This thin gap (800nm) SiO₂/Si₃N₄/SiO₂ gauge can measure absolute pressure from atmospheric to less than 1mTorr without sophisticated interface electronics by using a reliable software calibration technique. This allows the sensor to be integrated with common vacuum packaging technologies to measure leak rates as low as 10^-17cm³/s. This represents a 5 order of magnitude improvement over traditional helium leak testing with a substantially reduced cost.