Positive electron beam resists

Claim 1

In the method of producing a positive resist image comprising the step of (a) exposing a portion of a film of polymeric material to electron beam radiation until the exposed area experiences a degradation in molecular weight resulting in a change of solubility and (b) removing the degraded polymer of the exposed area by dissolution with a solvent, the improvement comprises said polymeric material being polymerized or copolymerized units of (A) 0 to 95 mol % of at least one alkyl ester of methacrylic acid having from 1 to 20 carbon atoms in the alkyl moiety; (B) 5 to 100 mol % of at least one monomer corresponding to the formula ##STR4## wherein n is zero or one and one of X and Y is always hydrogen and X or Y is phenyl or napthyl substituted by at least one halogen, or phenyl or napthyl substituted by at least one alkyl having from 1 to 8 carbon atoms, alkoxy having from 1 to 8 carbon atoms, carboxyl, cyano, carboxyalkyl having from 1 to 4 carbon atoms in the alkyl moiety, or alkylcarbonyl having from 1 to 8 carbon atoms in the alkyl moiety provided that when n is one, at least one of X or Y is hydrogen and the other of X or Y, if not a hydrogen atom, is as hereinbefore defined or a halogenoalkylcarbonyl having from 1 to 4 carbon atoms in the alkyl moiety or a halogen acrylcarbonyl; (C) 0 to 30 mol % of an α,β-monoolefinically unsaturated carboxylic acid having from 3 to 5 carbon atoms; (D) 0 to 40 mol % of acrylamide, methacrylamide or an N-mono- or N-di-alkyl ester thereof having from 1 to 8 carbon atoms in each alkyl moiety; and (E) 0 to 70 mol % of styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl chloride, vinylidene chloride, a vinyl alkyl ether having from 1 to 8 carbon atoms in the alkyl moiety, an allyl acetate, maleic imide, maleic anhydride, maleic acid, or mixtures thereof; with the sum of all of the molar percentages of components (A), (B), (C), (D), and (E) being 100.