Patent ID: 8585910

Claim:
A process of fabricating a microtube of a microfluidic device, the process comprising the steps of: providing a first substrate; isotropically etching a first surface of the first substrate to define therein a channel having an arcuate cross-sectional profile; isotopically etching a first surface of a second substrate to define therein a channel having an arcuate cross-sectional profile; forming a substrate structure by bonding the first surface of the first substrate to the first surface of the second substrate so that the channels thereof are enclosed between the first and second substrates to define a passage having a cross-sectional profile defined by each of the channels of the first and second substrates; thinning the substrate structure by etching a second surface of the first substrate opposite the first surface thereof and by etching a second surface of the second substrate opposite the first surface thereof to define side portions of the substrate structure that are separated by the passage; bonding the side portions of the substrate structure to a third substrate such that a portion of the substrate structure containing the passage is spaced apart from a surface of the third substrate; and then removing the side portions of the substrate structure so that the portion of the substrate structure defines a microtube that projects over the surface of the third substrate and has external walls surrounding the passage, the removing step simultaneously releasing the microtube so as to be capable of movement relative to the surface of the third substrate.