Micromachining of buried micro channels in silicon

A new method for the fabrication of micro structures for fluidic applicatio ns, such as channels, cavities, and connector holes in the bulk of silicon wafers, called buried channel technology (BCT), is presented in this paper. The micro structures are constructed by trench etching, coating of the sid ewalls of the trench, removal of the coating at the bottom of the trench, a nd etching into the bulk of the silicon substrate. The structures can be se aled by deposition of a suitable layer that closes the trench. BCT is a pro cess that can be used to fabricate complete micro channels in a single wafe r with only one Lithographic mask and processing on one side of the wafer, without the need for assembly and bonding. The process leaves a substrate s urface with little topography, which easily allows further processing, such as the integration of electronic circuits or solid-state sensors. The esse ntial features of the technology, as well as design rules and feasible proc ess schemes, will be demonstrated on examples from the field of mu-fluidics , [482].