Fabrication of Microfluidic Devices by Thermoplastic Molding and Diaphragm Transfer

A process for manufacturing microfluidic devices has been developed at Karlsruhe Research Center which allows such devices to be produced in a cost-effective way. They are assembled in a batch process from microstructures produced by molding and membranes fabricated by spin-coating and patterned by photolithography. Thermo-pneumatic actuators are made with heater wires on top of the membrane and actuator chambers on top of the heater wires. This process is used to manufacture micropumps and microvalves. Microvalves normally open as well as bistable have been realized with overall dimensions of a few millimeters and less. The production process has been employed in small-scale production of micropumps from polysulfone. Microfluidic handling modules consisting of four micropumps were combined with sensor modules for use in chemical microanalysis systems.