Vertical-Comb-Driven Tip-Tilt 32×32 Micromirror Array Based on Double-SOI and Single-Crystalline-Silicon TSV

Aimed at increasing the yield rate of large-scale vertical-comb-driven tilt-tip (TT) micromirror array (MMA), this paper, for the first time, introduces double-SOI (D-SOI) and our previously-proposed single-crystalline-silicon (SCS) TSV into its development. D-SOI has two mutually-insulated device layers (top device layer and middle device layer), which is well suited for the fabrication of isolated vertical comb drives. The SCS TSV is based on filling and oxidation of silicon powders (FOSP) for through silicon insulation. The D-SOI wafer is bonded to the FOSP-based SCS TSV wafer after lower comb sets are etched on its top device layer, followed by removing its handle layer and etching its middle device layer to form upper comb sets, gimbal frames, springs and reflectors. Based on the proposed fabrication process, a vertical-comb-driven TT 32×32 MMA is fabricated successfully, whose pixel dimension is 951μm×1000μm, pixel fill factor is about 50%, and driving voltage is about 22V/26V for 1°.