A 2-axis comb-driven micromirror array for 3D MEMS switches

Presents a new architecture of a 2-axis comb-driven micromirror array that combines a large deflection angle in a stationary operation, a low drive voltage, and easy scalability for a 3D MEMS switch. By using an SOI wafer with 100-/spl mu/m thick top and bottom Si layers and a 1-/spl mu/m buried oxide layer and, bulk micromachining with DRIE, we fabricated a 2-axis comb-driven micromirror array with a V-shaped torsion bar and comb teeth. The V-shaped torsion bar that has an optimized spring constant that enables both a large rotational angle and a low drive voltage without creating the undesired pull-in motion of the comb teeth. To implement a 2-axis tilt motion, we fabricated a gold bump for creating a gap under the comb teeth on the electrode substrate and mounted the mirror array substrate onto the electrode substrate by using the flip-chip-transfer technique. We fabricated an 80/spl times/80 switch chip and achieved a +/-5 degree rotation of the 2-axis stationary operation with a 60-V drive voltage.