A micro in-situ Pirani vacuum gauge for microsystem package applications

A novel micro-Pirani vacuum gauge applied in micro-system packages has been experimentally investigated. The gauge consists of a micro metal hot-wire, which is bonded on the pads of the LTCC substrate of a microsystem package and hangs over a cavity micromachined into the substrate. With a simple structure, this gauge may provide an in-situ and real-time monitoring of the vacuum inside the chamber of microsystem packages. This paper looks into the fundamental characteristics of this kind of micro-Pirani gauge. The performance characteristic curves are measured for metal wires with various length and current load. Based on the data thus obtained, the impacting factors are found out to optimize the micro-Pirani gauge.