Methods to improve reliability of bulge test technique to extract mechanical properties of thin films

Abstract

Knowledge of thin films mechanical properties is strongly associated to the reliability and the performances of Micro Electro Mechanical Systems (MEMS). In the literature, there are several methods for micro materials’ characterization. Bulge test is an established non destructive technique for studying the mechanical properties of thin films. This technique is easy to implement and to use, but there are important issues that can distort the characterization results. In this paper, we set up a rigorous experimental protocol in order to improve the reliability of mechanical characterization by bulging test. First we analyse and examine the parameters involved in the test bench. Then we propose some methods to improve the accuracy of the measurement. Crystalline silicon free-standing membranes were fabricated and characterized in order to calibrate the test bench.