ELECTROSTATIC ALUMINUM MICROMIRRORS USING DOUBLE-PASS METALLIZATION

The fabrication of aluminum spatial light modulators has so far requir ed costly process engineering efforts. In this paper, a low-cost proce ss approach is presented, suitable for the manufacture of electrostati c micromirror arrays. The mirrors are made from the second metallizati on of complementary metal oxide semiconductor (CMOS) or bipolar proces ses deposited in two passes. This metal2 is protected by a photoresist layer that can be patterned using the top passivation mask of the pro cess. No additional layer deposition and layer structuring is necessar y during postprocessing. The actuators are released in a simple surfac e micromachining postprocessing sequence based on a sacrificial alumin um and silicon dioxide etch. Our approach allows one metallization to be used for both the circuitry and the electrooptomechanical devices. Deformable mirror arrays of up to 16 x 16 pixels were fabricated. Stat ic self-consistent electromechanical simulations using the finite-elem ent method (FEM) toolbox SOLIDIS were performed for a theoretical anal ysis and optimization of the actuator devices. [217]