Silicon probe for micromachined surface profilers

Abstract

A single-crystal silicon probe for micromechanical surface profilers is presented, which uses a double-ended tuning fork (DETF) resonator as the displacement-sensing element. In addition, a two-stage micro-leverage mechanism for force amplification is introduced to increase the overall sensitivity. The frequency shift of the DETF caused by the induced axial stress is directly proportional to the displacement input. The probe was fabricated through a standard silicon-on-glass process, which can realise high aspect ratio single-crystal silicon structures. The experimental results indicated that the probe had a nominal resonant frequency of 54.5 kHz under atmosphere at room temperature. The scale factor and linearity of the probe with the input range of 0–10 µm were evaluated to be 359.7 Hz/µm and 6.3%, respectively. The measured scale factor shows good agreement with the simulated value of 330 Hz/µm using ANSYSTM.