Design and fabrication of a silicon probe for surface profilers

A micromachining probe for surface profilers is reported in this paper. This probe employs single crystal silicon double-ended tuning forks (DETFs) as the sensitive unit to achieve high resolution and frequency read-out. The frequency shift of the DETFs caused by the induced axial stress is directly proportional to the undulation of the measured surface. Moreover, one-stage and two-stage microleverage amplification mechanisms are respectively implemented to improve the probe performance. The silicon on glass (SOG) process which can provide high aspect ratio single crystal silicon structures has been adopted to enhance the performance of the probes. The testing results indicate that the probe with two-stage mechanical amplifiers has a frequency-displacement sensitivity of 257.1 Hz/μm with a nominal frequency 27.3 kHz at room temperature in atmosphere, which is in close agreement with the simulation results.