Scientific Drivers Fabrication of new types of electronic, magnetic, and optical devices currently consists of redesigning existing structures in down-sized versions. With these techniques we are able to generate patterns with critical dimensions as small as 30 nm. The stamps can be prepared by casting prepolymers against masters patterned by conventional lithographic techniques, as well as against other masters of interest. Several different techniques are known collectively as soft lithography. A transparent PDMS phase mask with relief on its surface is placed in conformal contact with a layer of photoresist.
Light passing through the stamp is modulated in the near-field.
Replica Molding . A PDMS stamp is cast against a conventionally patterned master. Polyurethane is then molded against the secondary PDMS master. In this way, multiple copies can be made without damaging the original master. Continuous channels are formed when a PDMS stamp is brought into conformal contact with a solid substrate.