PHOTO-ASSISTED SILICON MICROMACHINING - OPPORTUNITIES FOR CHEMICAL SENSING

Micromachining methods allow for the fabrication of small, three-dimen sional structures including membranes, micro-valves, and pumps, channe ls, etc., in materials such as silicon. When integrated with microcirc uitry this provides for the opportunity of creating unique miniature ' smart' chemical sensing devices. We present a novel method of photo-as sisted electrochemical silicon micromachining which allows for the fab rication of stress-free submicrometer thick beams, membranes, and high aspect ratio three-dimensional structures, whose complex surface topo logies were previously inaccessible by conventional processing routes. We discuss a number of gas and chemical sensor structures which benef it from MEMS technology and would benefit further from the processing versatility provided by our new micromachining fabrication method.