Optical Lever Based Parylene Cantilevers for Biochemical Sensing

Abstract

This paper reports the development of optical lever based parylene cantilevers for biochemical sensing. A simple but effective process to fabricate parylene cantilevers using Tetramethylammonium Hydroxide (TMAH) bulk-micromachining was demonstrated. A scheme of using anchoring holes was employed to prevent the peeling off of parylene during TMAH etching. Moreover, ridge structures were incorporated on the cantilever tip to achieve a flat surface for a well-controlled reflected laser spot. An analytical model was presented to guide the design of the cantilever sensor. The stability of the parylene cantilever sensor in water and buffer solution was demonstrated. Based on optical lever method, the parylene cantilevers successfully detected vapour phase alkanethiols, and DNA molecules in buffer solution.