Polymeric Electron Beam Resists

Abstract

Crosslinking polymers may be used as negative acting resists. The product of the minimum charge dose required and the weight average molecular weight 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 are an important factor. It is recommended that these resists be prebaked at , stored and developed at , and postbaked at .