Fabrication of Suspended Polymer Microstructures Using Sacrificial Layer Micromolding and Patterned Substrate Micromolding

Two soft lithography based fabrication techniques were employed for fabricating mechanically independent, freely suspended polymer microstructure from poly(n-propyl methacrylate) (PPMA) and poly(methyl methacrylate) (PMMA). Both methods involve a micromolding process followed by thermal bonding to the substrate. The first method, sacrificial layer micromolding, uses a water-soluble sacrificial layer, allowing functional structures to be released by immersion in water. The second method, patterned substrate micromolding, uses a permanent substrate patterned via photolithography. Functional regions of the polymer structures are suspended over the voids in the photoresist pattern. The processes have been applied to the fabrication of polymer microstructures with a variety of geometries for specific applications. Devices have included microcantilevers, beams, and other more complicated microstuctures. The thermal molding process is conceivably applicable to the fabrication of microstructures from a wide variety of thermoplastic polymers, allowing material selection to be tailored based on application.