Title :
Subnanometer Translation of Microelectromechanical Systems Measured by Discrete Fourier Analysis of CCD Images
Author :
Yamahata, Christophe ; Sarajlic, Edin ; Krijnen, Gijs J M ; Gijs, Martin A M
Author_Institution :
Lab. of Microsyst., Ecole Polytech. Fed. de Lausanne, Lausanne, Switzerland
Abstract :
In-plane linear displacements of microelectromechanical systems are measured with subnanometer accuracy by observing the periodic micropatterns with a charge-coupled device camera attached to an optical microscope. The translation of the microstructure is retrieved from the video by phase-shift computation using discrete Fourier transform analysis. This approach is validated through measurements on silicon devices featuring steep-sided periodic microstructures. The results are consistent with the electrical readout of a bulk micromachined capacitive sensor, demonstrating the suitability of this technique for both calibration and sensing. Using a vibration isolation table, a standard deviation of σ = 0.13 nm could be achieved, enabling a measurement resolution of 0.5 nm (4σ) and a subpixel resolution better than 1/100 pixel.
Keywords :
CCD image sensors; capacitive sensors; discrete Fourier transforms; microsensors; optical microscopes; CCD images; DFT; MEMS; bulk micromachined capacitive sensor; charge-coupled device camera; discrete Fourier transform analysis; electrical readout; in-plane linear displacements; microelectromechanical systems; optical microscope; phase-shift computation; steep-sided periodic microstructures; subnanometer translation; vibration isolation table; Accuracy; Discrete Fourier transforms; Micromechanical devices; Microscopy; Optical imaging; Optical sensors; Pixel; Discrete Fourier transform (DFT); optical measurement; phase correlation; subpixel resolution;
Journal_Title :
Microelectromechanical Systems, Journal of
DOI :
10.1109/JMEMS.2010.2067445
