Mechanical Characterization of MEMS-Microphones by Means of Nanoindentation and Coupled Finite Element Analysis

Within this paper, we present a mechanical characterization method using the nanoindentation technique for representing the failure mode occurring during drop of MEMS-microphones (MEMS: Micro-Electro-Mechanical Systems). Different indenter tip geometries and their influence on the enforced load and damage of the microphone structure are investigated. Cylindrical tips have been found to represent the drop-failure in a best manner by enforcing a comparable load case and damage configuration. Then, the experimental findings are correlated to finite element models to get a deep insight about the mechanical stress situation. By utilization of the extended finite element method XFEM as implemented in ABAQUS [1], the fracture of the microphone supporting structure are represented. Finally, a design study is performed, showing the influence of the support spring design on the mechanical as well as acoustical behavior.