Towards Measuring Young’s Modulus by Electronic Probing

We propose an accurate and precise method for measuring the Young’s modulus of MEMS with comb drives by electronic probing of capacitance. The electronic measurement can be performed off-chip for quality control or on-chip after packaging for self-calibration. Young’s modulus is an important material property that affects the static or dynamic performance of MEMS. Electrically-probed measurements of Young’s modulus may also be useful for industrial scale automation. Conventional methods for measuring Young’s modulus include analyzing stress-strain curves, which is typically destructive, or include analyzing a large array of test structures of varying dimensions, which requires a large amount of chip real estate. Our method measures Young’s modulus by uniquely eliminating unknowns and extracting the fabricated geometry, displacement, comb drive force, and stiffness. Since Young’s modulus is related to geometry and stiffness that we find using electronic measurands, we are able to express Young’s modulus as a function of electronic measurands. We verify our method by using it to predict the Young’s modulus of a computer model. We treat the computer model as we would treat a true experiment by depending only on its electronic measurands. We find good agreement in predicting the exactly known Young’s modulus in a computer model within 0.1%.