Abstract: To characterize the effect of deformation of die-bonding packages on the performance of MEMS devices,a laser scanning vibrometer was used,based on the theory of vibration analysis and signal processing.Because it is a commonly used structure in MEMS design,a surface micromachined polysilicon fixed-fixed beam was chosen.Its resonant frequencies from the 1st to the 3rd order were recorded before and after die bonding and compared to FEM simulations.The results suggest that the thermo-mechanical coupling deformation in the multilayer packaging structure affects the performance of MEMS device remarkably,and the resonant frequencies shift of the beam are more than 15%~30%.Therefore,it is possible to include the package effect in the primary design circle of MEMS devices,which may enhance the device performance and shorten the primary design cycle.

Key words: MEMS, packaging effect, fixed-fixed beam, resonant frequency, co-design