Patent ID: 6869745

Claim:
A positive-working chemical-amplification photoresist composition which comprises, as a uniform solution in an organic solvent: (A) 100 parts by weight of a combination of a first copolymeric resin consisting of from 62 to 68% by moles of monomeric units (a) hydroxyl group containing styrene units, from 15 to 25% by moles of monomeric units (b) styrene units and from 12 to 18% by moles of monomeric units (c) acrylate or methacrylate ester units each having a solubility-reducing group capable of being eliminated in the presence of acid and a second copolymeric resin consisting of from 62 to 68% by moles of the monomeric units (a), from 25 to 35% by moles of the monomeric units (b) and from 2 to 8% by moles of the monomeric units (c) wherein the first copolymeric resin is present in a weight ratio with respect to the second polymeric resin in the range from 9:1 to 5:5 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 3 to 10 carbon atoms as the anion.