Method for fabricating a through-wafer optical MEMS device having an anti-reflective coating

摘要

An optical MEMS device is fabricated in either a surface or bulk micromachining process wherein an integral process step entails providing an antireflective coating on one or more surfaces of a substrate through which optical information is to be transmitted. In one method, a surface micromachining process is carried out in which a sacrificial layer is formed and patterned on an optically transmissive substrate. A structural layer is formed on the sacrificial layer and fills in regions of the sacrificial layer that have been removed. An amount of the sacrificial layer is removed sufficient to define and release a microstructure and thereby render the microstructure movable for interaction with an optical signal directed toward the optically transmissive substrate. In another method, a bulk micromachining process is carried out in which a first substrate is provided that is composed of an optically transmissive material. An antireflective coating is deposited on a major surface of the first substrate to enable an optical signal to be transmitted along a path directed through the antireflective coating and the first substrate. A movable, actuatable microstructure is formed a second substrate. The first and second substrates are aligned and bonded together in a manner enabling the microstructure to interact with the optical signal upon actuation of the microstructure.