Using Elastomeric Membranes as Dry Resists and for Dry Lift-Off

Elastomeric membranes that contained regular arrays of well-defined holes were formed by spin-coating a prepolymer onto a photolithographically defined master. These membranes were used as dry resists or as masks in dry lift-off to produce simple features as small as 5 μm on both planar and nonplanar surfaces. These procedures were "dry" because the membranes conformed and sealed reversibly to surfaces: no solvent was required either to deposit the membrane or to remove it from the substrate. A variety of materials, some of which would be difficult to pattern using conventional methods, were patterned using this technique. These materials included metals, sol−gels, hydrogels, biological macromolecules, and organometallic molecules. The membranes were used in sequential, dry-lift off steps to produce structures with greater complexity than those generated with a single membrane.