Paul Joseph - Soft Lithography Methods of Fabrication

Soft lithography (SL) refers to a family of techniques for fabricating or replicating structures using elastomeric stamps, molds, and conformable photomasks. Fabrication of microfluidic devices by SL is the most popular approach due to simplicity and low cost. In this approach PDMS (polydimethylsiloxane) is cast on a SU-8 master mold to generate elastomeric stamps that are then sealed against glass slides using oxygen plasma. SL plays a vital role in microfluidics, ranging from simple channel fabrication with inlet/outlet to the creation of micropatterns onto a substrate surface. SL includes a collection of fabrication methods that are all based on using an elastomeric (or PDMS) stamp. These methods with reference to Microfluidics device fabrication (µDF), Replica Molding (REM), Micro-contact printing (µCP), Micro-transfer molding (µTM), and Micro-molding in capillaries (MIMIC) will be presented. The goal for this presentation is to impart a basic understanding of soft lithography for microfluidic applications as practiced in academia and industry