Mechanical Reliability Evaluation and its Standardization of Thin Films Used in MEMS

Abstract

Thin film tensile testers equipped with an electrostatic grip have been developed for the evaluation of the mechanical reliability of thin films in microelectromechanical systems, and mechanical reliability evaluations of thin films were described in this paper. The electrostatic grip uses an electrostatic force in order to fix thin film specimen of less than 2 μm thick. Single crystal silicon, polysilicon, silicon dioxide, silicon nitride, and titanium films were tested using the testers. Specimen dimensions ranged from 1 to 50 μm in width, from 0.05 to 5 μm in thickness, and from 10 to 600 μm in length. The tensile strength, Young’s modulus, and fracture behavior were investigated. In order to improve the accuracy and the reliability of tensile strength measurements, standardization of the mechanical properties evaluation is being carried out in collaboration of researchers in Japan. The results from the comparison between the existing testing methods were described.