A versatile surface channel concept for microfluidic applications

MEMS fluidic devices often require the integration of transducer structures with freely suspended microchannels. In this paper a versatile microchannel fabrication concept is presented, allowing for easy fluidic interfacing and integration of transducer structures in close proximity to the fluid. This is achieved by the reliable fabrication of completely sealed microchannels directly below the substrate surface. The resulting planar substrate surface allows for the deposition of transducer material and pattern transfer by lithography. The microchannels are subsequently released and fluidic entrance holes are created, while the transducer structures can be protected by photoresist. Several monolithic microfluidic device structures have been fabricated, demonstrating the versatility of the concept. Fabricated surface microchannel devices can optionally be vacuum sealed by anodic bonding.