An Improved SOI-on-Glass Fabrication Method of Large-Area Sheeting of MEMS Isolator

Abstract

Vibration isolators are utilized to help large-area micromirrors survive in the AEC-Q100 test. The supporting platform of the isolator, however, involves a larger area of movable silicon sheeting and is hard to be fabricated by direct etching due to the collapse and adhesion caused by thermal deformation. In this paper, an SOI-on-Glass (SOIOG) process is proposed to fabricate a large area of sheeting with a controllable air gap and four flexible beams. Six sacrificial pillars are introduced to prop up the sheeting in the center before structure release. Meanwhile, the pillars can increase heat dissipation to reduce thermal deformation during the DRIE process. Finally, an isolator with a $20.2 \mathrm{~mm} \times 14.2 \mathrm{~mm}$ sheeting is fabricated successfully.