Flexible fabrication of large pixel count piston-tip-tilt mirror arrays for fast spatial light modulators

We present arrays of electrostatically actuated piston-tip-tilt micromirrors realized using a surface micromachining 3-structural-layer polysilicon process. High fill factor, flat mirrors 120 pm in size have mechanical response in the order of 10 mu s, with +/- 4 degrees mechanical tip and tilt and 5 mu m piston continuous, controllable range under 110 V. The actuator design is based on four dual in-plane comb drives with 0.5 mu m critical feature size and high aspect ratio. We show a modular approach to fabricate these arrays, allowing multiple array sizes (64(2) and 256(2) mirrors) and four different designs to be implemented in three DUV masks per lithography level. (c) 2007 Elsevier B.V. All rights reserved.