Laser ultrasound measurement of diaphragm thickness, Young’s modulus and Poisson’s ratio in a MEMS device

McKee, Campbell; Culshaw, Brian; Leach, Richard K.

Abstract

Laser-generated Lamb waves, coupled with a large bandwidth Michelson interferometer, have been demonstrated to accurately measure the thickness of a MEMS pressure sensor diaphragm in the [110] direction of a silicon wafer. Using the reassigned Gabor time-frequency method to produce group velocity dispersion curves, the technique facilitates the measurement of thickness, Young’s modulus and Poisson’s ratio from just one non-contact measurement. In this investigation, thickness was determined to be 35.01 μm ± 0.18 μm. For comparison, the thickness was measured using an independent optical technique; obtaining a value of 34.60 μm ± 0.27 μm. Values for Young’s modulus and Poisson’s ratio were also determined to be 163 GPa ± 11.7 GPa and 0.351 respectively and these are in good agreement with values found in the literature.

Citation

McKee, C., Culshaw, B., & Leach, R. K. (in press). Laser ultrasound measurement of diaphragm thickness, Young’s modulus and Poisson’s ratio in a MEMS device. IEEE Journal of Selected Topics in Quantum Electronics, https://doi.org/10.1109/JSTQE.2016.2635518

• Journal Article Type: Article
• Acceptance Date: Dec 2, 2016
• Deposit Date: Feb 21, 2017
• Journal: IEEE Journal of Selected Topics in Quantum Electronics
• Print ISSN: 1077-260X
• Electronic ISSN: 1558-4542
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1109/JSTQE.2016.2635518
• Keywords: Elastic modulus, Elasticity, Laser ultrasonics, Microelectromechanical systems (MEMS), Poisson’s ratio, Silicon, Young’s modulus
• Public URL: https://nottingham-repository.worktribe.com/output/836733
• Publisher URL: http://dx.doi.org/10.1109/JSTQE.2016.2635518
• Additional Information: (c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.
• Contract Date: Feb 21, 2017