SU-8 lift-off patterned silicone chemical vapor sensor arrays

This paper reports on the fabrication and preliminary characterizations of our micromachined silicone/carbon black chemical vapor sensor arrays. By utilizing SU-8 lift-off technique, we have successfully patterned room temperature vulcanizing (RTV) polymers down to 25 μm feature size using low resolution mask (with line-width of 5-10μm) with yields in excess of 90% throughout a 4" silicon wafer. Based on this technique, we have fabricated the smallest functional polymer/carbon black based chemical vapor sensor (60×60×25μm³) reported in the literature known to the authors thus far. Preliminary characterizations showed that the sensors are capable of sensing alcohols and acetone in the range from 2.5ppth to 12.5ppth with response time down to 5 seconds.