Patent ID: 7381628

Claim:
A process of fabricating a micromachined tube for fluid flow therethrough, the process comprising the steps of: providing a first wafer having a thickness throughout which the first wafer has a substantially uniform doping level and a second wafer having a thickness throughout which the second wafer has a substantially uniform doping level; etching a channel in a first portion of the first wafer in a direction of the thickness thereof, the channel extending through more than half but not entirely through the thickness of the first wafer, the channel being between second and third portions of the first wafer; bonding the first wafer to the second wafer so that a first portion of the second water overlies the first portion of the first wafer and encloses the channel therein to define a passage, and so that second and third portions of the second wafer overlie the second and third portions of the first wafer; thinning the second wafer so that the first portion thereof defines a thinned wall of the passage, wherein the thinned wall has a thickness of about 10 to about 100 micrometers; removing the second and third portions of the second wafer and some but not all of the second and third portions of the first wafer underlying the second and third portions of the second wafer, such that the first portions of the first and second wafers define a protrusion; bonding the thinned wall defined by the first portion of the second wafer to a substrate adjacent a recess in a surface of the substrate such that a portion of the passage projects over the recess; and then removing the second and third portions of the first wafer such that the thinned wall defined by the first portion of the second wafer, walls defined by the first portion of the first wafer, and the passage therein define a tube, a freestanding portion of the tube projecting over the recess in the substrate so as to be capable of movement relative thereto.