Mechanical reliability of MEMS-structures under shock load

For automotive applications, the mechanical reliability of MEMS-structures in accelerometers and gyroscopes has to be ensured for harsh conditions. In this paper, we consider shock-type loads which arise during drop-tests. Th ese may lead to unforeseen contact of moving structures, inducing large str esses potentially damaging the structures. We demonstrate an approach to im prove shock resistance using dynamic finite element analysis for the case o f polysilicon cantilevers. Comparison of the results with experimental data validates the feasibility of the approach, as the optimized design withsta nds loads three times higher than the initial design. By analyzing the stre ss history of the damaged regions, we are working towards an understanding of a failure criterion for polysilicon structures under shock load. (C) 200 1 Elsevier Science Ltd. Ail rights reserved.