Design of Micro-Plates Subjected to Residual Stresses in Microelectromechanical Systems (MEMS) Applicationss

Bakeer, Bahi; Elsabbagh, Adel; Hedaya, Mohammed

doi:10.21608/pserj.2021.54511.1084

Design of Micro-Plates Subjected to Residual Stresses in Microelectromechanical Systems (MEMS) Applicationss

Document Type : Original Article

Authors

¹ Design and Production Engineering Department, Faculty of Engineering, Ain Shams University University., Cairo, Egypt

² Design and Production Engineering Department, Faculty of Engineering, Ain Shams University, Cairo, Egypt

10.21608/pserj.2021.54511.1084

Abstract

Microelectromechanical Systems (MEMS) devices suffer from reliability problems which affect its performance. Fabrication process initiate residual stresses that cause stress stiffening and curling. It is shown from the previous research that reducing both stiffening and curling is a challenging issue. Analytical analysis for a fixed-fixed beam is done to determine the factors affecting stiffening in rectangular cross-section beams. A new U-shaped cross-section plate is proposed to decrease both stiffening and curling. The new U-shaped plate is compared with a reference flat plate with the same bending stiffness, length, width and material properties. In order to capture plate effects and biaxial residual stress, Finite Element model is developed. Results showed better performance of the U-shaped plate than the flat one. Curling and stiffening reduced by 72 and 42 %, respectively. Stiffness variation with temperature reduced by 43%, stabilizing the operational performance parameters such as pull-in voltage. Moreover, the critical buckling temperature of the U-shaped plate is greater than that of the flat one by 27 ℃, extending the operational temperature range of the plate. The fundamental natural frequency increased by 33%, due to the lower mass of the U-shaped plate. In general, high switching time is considered as another reliability problem in MEMS devices. The increase in fundamental natural frequency for U-shaped plate expects to reduce the switching time. The concept of U-shape plate can be used in many MEMS applications such as resonators, Radio-frequency (RF) switches, pressure sensors, and micromirrors in order to improve the reliability of these devices.

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