Fabrication processes for packaged optical MEMS devices

Abstract

Processes for the fabrication of packaged optical MEMS devices are presented. A single structural layer surface micromachining process for creating MEMS actuators and sensors is discussed. A base metal layer allows electrical routing. The structural layer is made of a stack of metal, dielectric, and metal to allow electrostatic actuation of parts, stiffness, and high optical reflectivity. All three structural layers are patterned using a single mask. The lower structural metal can be additionally patterned to allow isolated areas for electrical switching applications. Toward the goal of packaged optical devices, a new scheme for creating optically-transparent package lids, which are subsequently thermo compression bonded onto the surface micromachined parts, is also introduced. The fabrication technique allows creation of extremely vertical through-wafer surfaces in silicon, with minimal surface damage to the co-bonded glass lid. An optical corner cube retroreflector (CCR) communication device is presented as one application.