Challenges and Issues of Using Polymers as Structural Materials in MEMS: A Review

Polymers are ever more widely and more prominently used in microelectromechanical systems. They provide significant added value to the existing silicon-based technologies, such as flexibility, low stiffness, easy fabrication, and low cost. Nevertheless, the intrinsic properties of polymer materials also bring new challenges and issues to their applications as structural materials in MEMS devices, such as fabrication failures, electrical drift/failures (induced by charging, leakage, or breakdown), as well as mechanical drift/failures (induced by residual stress, environmental conditions, or viscoelasticity). This paper presents a review on the origin, impact, underlying physics, and mitigation methods to those challenges for polymer devices (especially SU-8).