US Patent 7171975 Fabrication of ultra-shallow channels for microfluidic devices and systems

A method for etching an ultra-shallow channel includes using an etch process that is selective for one material to etch a different material in order to achieve a very precise channel depth in the different material. Channels as shallow as 10 nm can be fabricated in silicon with precision of 5 nm or better using the method. Stepped channels can be fabricated where each segment is a different depth, with the segments being between 10 nm and 1000 nm in depth. The method is applied to create a fluidic channel which includes a channel substrate to which is bonded a lid substrate to confine fluids to the fluidic channels so fabricated.