Shape and thermal effects of metal films on stress-induced bending of surface micromachined curved grating

In this study, the shape and thermal effects of metal films on the stress-induced bending of micromachined curved grating are systematically investigated. The characterization of the curved grating with different shape has been performed to observe out-of-plane deformation. A finite-element model has been established to analyze such a deformation. Furthermore, the influence of postprocessing temperature on the residual stress of the metal films is examined. Experimental indicates that the postprocessing temperature and residual stress reveal a close relationship. As postprocessing temperature increases, the residual stress of the metal increases, resulting in a larger out-of-plane deformation of the curved grating. The proposed curved grating can be applied to optical measurement applications.