Design, fabrication and characterization of a MEMS safe pyrotechnical igniter integrating arming, disarming and sterilization functions

Abstract

We proposed a safe MEMS pyrotechnical igniter made of one micro igniter and three single-use electrothermal micro switches. One ON–OFF micro switch is used to arm the pyrotechnical initiator. One OFF–ON micro switch is used to disarm the pyrotechnical initiator by cutting its electrical connections from the power supply. A second ON–OFF micro switch definitively removes the pyrotechnical initiator's ignition capability. Switches are based on electrothermal mechanisms and consist in breaking one electrical connection (ON–OFF switching), or micro soldering locally two electrical connections (OFF–ON switching). The ON–OFF switching based on the decomposition of GAP energetic material requires 500 mW during 30 ms. The OFF–ON switch using a Ø350 µm Sn/Pb ball requires a minimum of 200 mW during 5 s to create a good intermetallic layer and therefore a good electrical contact. The fabrication process of both switches and igniter is based on classic MEMS technology steps including LPCVD, PECVD, copper electro deposition and plasma etching steps. Fabrication yield reaches 99%.