title: Optical Fourier transform based in-plane vibration characterization for MEMS comb structure.
abstract: On-line and on-wafer characterizations of mechanical properties of Micro-Electro-Mechanical-System (MEMS) with efficiency are very important to the mass production of MEMS foundry in the near future. However, challenges still remain. In this paper, we present an in-plane vibration characterizing method for MEMS comb using optical Fourier transform (OFT). In the experiment, the intensity distribution at the focal plane was captured to characterize the displacement of the vibrator in the MEMS comb structure. A typical MEMS comb was tested to verify the principle. The shape and the movement of MEMS comb was imitated and tested to calibrate the measurement by using a spatial light modulator (SLM). The relative standard deviations (RSD) of the measured displacements were better than 5%, where the RSD is defined as the ratio of the standard deviation to the mean. It is convinced that the presented method is feasible for on-line and on-wafer characterizations for MEMS with great convenience, high efficiency and low cost.
authors.affiliation: State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084, China.
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Gao
authors.forename: Liangcai
authors.initials: L
authors.lastname: Cao
authors.forename: Zheng
authors.initials: Z
authors.lastname: You
authors.forename: Jiahao
authors.initials: J
authors.lastname: Zhao
authors.forename: Zichen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Yang
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005374:Filtration / Q000295:instrumentation*; D005583:Fourier Analysis; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D055096:Optical Devices; D013685:Telecommunications / Q000295:instrumentation*; D014732:Vibration