Fabrication and testing of a novel silicon probe for micromachined surface profilers

In this paper, we present the fabrication and testing of a novel probe for micromechanical surface profiler with double-ended tuning forks (DETFs) resonator as the displacement-sensing element. The probe is fabricated through the standard silicon-on-glass process developed by Peking University. The frequency variation of the DETF caused by the induced axial stress is directly proportional to the input displacement. Two stages micro-leverage mechanisms are introduced for force amplification to increase the overall sensitivity. The experimental results indicate the device has a nominal resonant frequency of 54.5 kHz under atmosphere at room temperature and the overall sensitivity is approximately 359.7 Hz/μm, which shows a good agreement with the simulation value of 330 Hz/μm using ANSYS™. Furthermore, the testing results depict the variation of frequency is linear to the displacement load within the range of 10μm.