Abstract: Based on non-silicon surface micromachining technology, a simple but reliable micro electro-mechanical system (MEMS) electrical inertia micro-switch with single sensitive direction and reverse impact protection is designed and fabricated on glass substrate. In this design, conjoined serpentine springs are used to fix and suspend the mobile electrode (mass) and blocks are used to protect the device against reverse impulse. The switch is laterally driven (i.e. its sensitive direction is parallel to the substrate). Fabrication is carried out by low-cost and convenient multi-layer electroplating technology. The relationship between threshold acceleration and mass thickness has been investigated by theoretical analysis and finite element analysis (FEA) simulation. After fabrication and packaging, micro-switches are tested by using drop weight. The results show that the threshold accelerations distribute between 58g and 72g, which basically fulfils the expected 60g; and the response time to 100g half-sine waved shock is in the order of 10–4 s, which is in agreement with simulation result.

Key words: Inertia micro-switch, Micro electro-mechanical system, Non-silicon surface micromachining, Simulation, Threshold acceleration