Eigenfrequency Investigation of SU-8 Single Axis MEMS Piezoresistive Accelerometers

This paper presents experimental and analytical eigenfrequency evaluation of SU-8 polymer piezoresistive MEMS accelerometers using two different attachment beams, dual and quad structures. Beam thicknesses of 4.475 µm and 8.216 µm produce two different sets of prototypes with dual-beam attachments. Those with quad-beam attachments are only 8.216 µm thick. The dynamic characterization of the fabricated devices is performed to measure resonance frequency using Lazer Doppler Vibrometer (LDV). For a beam thickness of 8.216 µm, measured eigenfrequencies are 1325 Hz and 1813 Hz for dual and quad-beam attachments, respectively. Using experimental dimensions, analytical study is performed to evaluate the frequency response of the devices. Resonant frequencies obtained from analytical study are in good agreement with experimental ones. Maximum errors are 18% and 12% for the dual and quad-beam structures, respectively.