Electrical test structure for the measurement of hermeticity in electronic and MEMS packages with small cavity volumes

In this paper we present the first world realisation of a novel electromechanical sensor for the detection of hermeticity in low-cavity-volume packages. We designed, fabricated, and characterised this test structure. Its core element is a 0-level silicon cap acting as a piezoresistive deflecting membrane. The hermeticity of the package can then be determined in real-time. Low leak rates can be measured with a sensitivity two orders of magnitude lower than the limit of traditional helium fine leak test. Abraham’s contribution: development of theoretical model to calculate the voltage created by piezoresistors deposited on a square membrane