Photosensitive Glass for Ultra High Aspect Ratio Features
J.H. Flemming, R. Mack, C. Buckley
Life BioScience, Inc., US
Keywords: glass, aspect ratio, microfluidic, photosensitive
Abstract:Glass is a preferred substrate for microfluidic channels for a variety of reasons, including chemical inertness, optical clarity, and uniform surface chemistry. Unfortunately, many approaches to glass microfabrication are either expensive or are not scaleable for affordable high volume manufacturing. Life BioScience, Inc. (LBSI) presents an innovative photosensitive substrate, APEX™ Glass, for the microfabrication of high aspect ratio structures. This glass has four primary advantages over existing photosensitive glasses. First, aspect ratios greater than 50:1 may be easily microfabricated when using a flood exposure system, compared to 20:1 for other photosensitive glasses. Second, the resulting rectangle microchannel cross section, as opposed to hour glass cross sections for lower aspect ratio etches, will lead to better device-model correlations. Third, processing times of APEX™ Glass is up to 40% faster than other photosensitive glasses. Fourth, APEX™ Glass wafers are extremely uniform in their composition leading to yield rates greater than 90%; historically, commercially available photosensitive glasses have been very inhomogeneous and typically yield about 50% of their processed features. These four advantages make APEX™ Glass extremely user friendly and eliminate a lot of the processing guess work and frustrations which have previously plagued photosensitive glasses.