POLYMERIC ELECTRON BEAM RESISTS

Crosslinking polymers may be used as negative acting resists. The product of the minimum charge dose Q required and the weight average molecular weight Mw is a constant and is a characteristic of the polymer. At an electron beam voltage of 10 kV, this Q-M product is found experimentally to be 6.3 coul-g/cm2-mole for polystyrene, 1 coul-g/cm2-mole for poly (vinyl chloride), and 14 coul-g/cm2-mole for Polyacrylamide. Degrading polymers may be used as positive acting resists. Their average molecular weights have only a very minor effect on their efficiency as positive resists. Their glass transition temperatures Tg are an important factor. It is recommended that these resists be prebaked at T > Tg, stored and developed at T < Tg, and postbaked at T > Tg. © 1969, The Electrochemical Society, Inc. All rights reserved.