Optimization of the resonant frequency MEMS pressure sensor based on numerical simulation

Vtorushin S.E., Talovskaia A.A., Barbin E.S., Kulinich I.V., Vaisbekker M.S. Optimization of the resonant frequency MEMS pressure sensor based on numerical simulation. Scientific and Technical Journal of Information Technologies, Mechanics and Optics, 2025, vol. 25, no. 6, pp. 1067–1079 (in Russian). doi: 10.17586/2226-1494-2025-25-6-1067-1079

Silicon microelectromechanical pressure sensors of the resonant-frequency type are distinguished by high linearity and stability of their output characteristics, making them particularly promising for precision measurements. This paper presents a study of the influence of membrane geometry and stress-strain state on the sensitivity of resonant-frequency pressure sensors. Recommendations for optimal resonator placement and the selection of a process route for membrane formation are also developed. Using three-dimensional models of membranes of various geometric shapes, numerical simulation of their stress-strain state under static pressure was performed using the finite element method. This method allowed us to identify the zones of localized deformation most suitable for resonator placement. Wet etching with preliminary wafer thinning and subsequent finishing machining was used to fabricate test samples of silicon membranes. It is shown that maximum sensitivity is achieved by positioning the resonator in zones of peak tensile and compressive stresses. An analysis of the membrane shape relationship to stress distribution and resonator response was conducted, enabling the identification of optimal resonator locations in terms of manufacturing tolerances and sensitivity. Membrane preparation methods were compared: chemical and mechanical thinning followed by polishing. Based on roughness measurements for membranes manufactured using different methods, the optimal preparation technology was described. The obtained results enable optimization of the geometry and manufacturing process of the resonant-frequency pressure sensor, which contributes to increased sensitivity, wider manufacturing tolerances, reduced production costs, and improved reliability in industrial operation.

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