Study of Surface Deformation of MEMS Components using the FFT and Phase-shifting Interferometry

In this paper, we describe methods for the 3D test of MEMS micro-components using optical interferometry. Utilizing optical interference, microscope optics, PZT nano-scanning and a CCD camera, the proposed technique can detect deformations and measure surface contours with a precision of the order of nanometers. Application of the proposed technique is demonstrated by testing on two typical components: an accelerometer and a micro-mirror. The resulting interference fringes, that are related to deformation of the micro-beam and the surface profile of the micro-mirror, are analyzed by the fast Fourier transform (FFT) and 3-step phaseshifting algorithms. Experimental results from these components are given to demonstrate the feasibility of the proposed method for measuring 3D deformation and surface profiles of microcomponents and to highlight the potential of the proposed technique as a tool for materials research.