Positive-working chemical-amplification photoresist composition and method for forming a resist pattern using the same

Abstract

Disclosed is a novel positive-working chemical-amplification photoresist composition capable of giving an extremely finely patterned resist layer in the manufacturing process of semiconductor devices and a method for forming a finely patterned resist layer therewith. The photoresist composition comprises: (A) 100 parts by weight of a copolymeric resin consisting of from 50 to 85% by moles of (a) hydroxyl group-containing styrene units, from 15 to 35% by moles of (b) styrene units and from 2 to 20% by moles of (c) tert-butyl (meth)acrylate units; and (B) from 1 to 20 parts by weight of a radiation-sensitive acid-generating agent which is an onium salt containing a fluoroalkyl sulfonate ion having 1 to 10 carbon atoms as the anion such as diphenyliodonium trifluoromethane sulfonate. In the pattern-forming method with the photoresist composition, the photoresist coating layer is subjected to heat treatments before and after the pattern-wise exposure to light at a relatively low temperature of 100-110 ° C. so that a satisfactory patterning can be accomplished even for an isolated pattern having a line width as small as 0.15 μm.

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