Abstract: A lift-off mask for the patterned deposition of thin films comprises a three layer sandwich of photoresist-aluminum-photoresist on a substrate. Deposition occurs through an opening in the top photoresist layer and through larger size (i.e., undercut) openings in the aluminum and bottom photoresist layers. The top layer of photoresist remains on the mask during deposition and defines the pattern, the bottom photoresist is fully exposed and in the openings provides an undercut which prevents edge tearing during lift-off, and the aluminum layer (typically 50-200 Angstroms thick) protects the bottom layer of photoresist from dissolving during formation of the top photoresist layer. Also described is a technique in which the edges of thin films are tapered by depositing them from a direction oblique to the substrate surface and by rotating the substrate during deposition. These techniques are specifically discussed in the context of fabricating Josephson junction devices.