| Summary: | 碩士 === 華梵大學 === 機電工程研究所 === 95 === This paper presents a novel and high-precision algorithm and method for stability analysis of micro electromechanical structures. The contents are extracting the Young’s modulus and residual stress of thin films through the pull-in voltage of the micro test-key at wafer level. For theory deducing, firstly we use energy method to drive out the bending strain energy and electrical potential energy of the micro fixed-fixed beam sudjected to electrostatic loads. Secondly, the analytical solution to the pull-in voltage is derived based on the minimum energy method with Taylor’s series expansion and assumed deflection shape function. Then one can use the aforesaid analytical solution of the pull-in voltage to extract the Young’s modulus and residual stress of the micro fixed-fixed beam. The proposed analytical model is verified by comparing with the published literatures. It is shown that the proposed three different models agree very well with the published works. In addition, the Young’s modulus and residual stress extracted by the proposed algorithms are also very close to the data in the literatures. The Surface micromachining compatible with the CMOS process was used in our experiment with aluminum as the testing structural material. Compared to the experimental measurements, the deviations of the extracted Young’s modulus and residual stress are also very close and within confident intervals.
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