Mechanical Response of Surface-Micromachined Beams Exposed to Short-Pulse Laser Irradiation

Due to the small dimensions of microelectromechanical systems (MEMS), real-time imaging and metrology techniques must be developed for characterizing MEMS devices. This paper describes an interferometric imaging system used to visualize the mechanical response of MEMS structures during laser irradiation. By incorporating a high-speed CCD camera into the interferometric imaging system, video showing the transient repair of adhered microcantilevers is captured. The video clearly reveals that the failed structures peel from the substrate as they are repaired. The time-scale for repair is on the order of ten milliseconds and depends on the temperature difference between the cantilever and substrate created by the laser. Transient buckling and relaxation due to differential thermal expansion and subsequent cooling is also captured using the transient imaging system. These experimental results provide insight into the energy absorption and transport processes in microstructures during and after laser heating.