Projection photolithography-liftoff techniques for production of 0.2-µm metal patterns

A technique which allows the use of projection photolithography with the photoresist liftoff process, for fabrication of Submicrometer metal patterns, is described. Through-the-substrate (back-projection) exposure of the photoresist produces the undercut profiles necessary for liftoff processing. Metal lines and superconducting microbridges of 0.2-µm width have been fabricated with this technique. Experimental details and process limits are discussed.