Microcantilevers encapsulated in fluid wells for sensing in liquids

We fabricated arrays of cantilever sensors suspended deep inside fluid wells. To eliminate critical alignment and assembling steps during encapsulation of the cantilevers, these 3-D MEMS devices are realized in a single-side, single-wafer process by employing photolithography on bulk micromachined substrates. Silicon nitride cantilevers with varying geometries are suspended up to 100μm below the wafer surface, and a structured gold layer is patterned on top. After calibrating the cantilevers in an optical lever setup, the formation of a DNA monolayer on the cantilever surface is detected.

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► Cantilever sensors integrated in individual fluid wells.
► Gold patterning by contact lithography through a 100 μm gap.
► Encapsulated cantilever sensors in a single wafer by single-side processing.
► Capping MEMS without alignment.