US Patent 7633035 Reverse side film laser circuit etching

A direct-write laser lithography system comprises a reel-to-reel feed system in a vacuum chamber that presents the clear film-side of a single-sided metal-clad tape to a laser for direct patterning of the metal. The laser beam is swept laterally across the tape by rotating mirrors, and is intense enough to ablate the metal but not so strong as to destroy the tape substrate. In one instance, two specialized lasers are used, one set to ablate large field areas, and the other tuned to scribe fine features and lines. The ablated metal blows off in a downward direction and is collected for recycling.