Patent ID: 8141573

Claim:
A method of fabricating a micro check valve having a floating member for controlling flow of fluid, the method comprising: depositing a plurality of polymer layers and a plurality of sacrificial layers on a substrate in an alternating manner, the substrate comprising a multi-level valve seat, the plurality of polymer layers including a first polymer layer comprising the floating member, a second polymer layer comprising a valve cap, and a third polymer layer comprising an outer wall defining a fluid channel; and removing the plurality of sacrificial layers, thereby forming an in-channel microfluidic valve having a floating polymer member that is movable between the valve seat and the polymer valve cap by application of pressure on the floating member by a fluid to passively control flow of the fluid through the multi-level valve seat and the valve cap, wherein the multi-level valve seat, the valve cap and the floating member are configured to permit flow of the fluid when the fluid pressure is between a threshold pressure and a cut-off pressure and to stop flow of the fluid when the fluid pressure exceeds the cut-off pressure.