A reliable test key for thin film mechanical properties characterization

In this study, a reliable test key using resonant technique to characterize the mechanical properties of thin film materials is reported. The test key consists of micromachined cantilever array that are fabricated using the thin film to be determined. The Young's modulus, Shear modulus, and Poisson's ratio of the thin film are successfully extracted after the natural frequencies of bending and torsional modes are measured. In applications, this technique has been employed to determine the mechanical properties of SiO/sub 2/ film fabricated from bulk micromachining processes. Moreover, the test key has also been used to determine the mechanical properties of poly-silicon layers in MUMPs surface processes.