Polyimides in lithography

Polyimides and Polyamide-imides have a high thermal and dimensional stability, good properties, and resistance to attack by solvents. These features, along with their electrical properties, have led to their wide acceptance in the electronics industry. Specifically, Polyimide masks are superior to conventional resists during metal deposition, sputter etching, and chip soldering, for which high-temperature stability is essential. Such a mask is prepared by selectively etching the polyamide-imide with in organic solvent such as ethylenediamine. The reaction of ethylenediamine with polyamide-imides has been applied successfully in metallizing semiconductors by the lift-off method; also, polyamide-imides have been used as a reworkable protective coating for semiconductor modules.