Polymer Material Grating Used on Contactless Sub-Wavelength MEMS Physical Sensors

We will present a novel detecting principle for MEMS physical sensors based on contactless optical property through periodic sub-wavelength gratings formed by polymer material. This approach employs the wire-grid polarizer (WGP) structure which was fabricated by laser interference lithography (LIL) system and inductively coupled plasma (ICP) dry etching method on the silicon substrate. The WGP transform the deflection of the cantilever beam to the P-polarized of the transmitted light (T-p). In this way, we can get high sensitivity sensing signal directly by the photodetector without physical influence in the MEMS structure.