Patent ID: 6864036

Claim:
A negative-working photoresist composition which comprises, as a uniform solution in an organic solvent: (A) 100 parts by weight of an alkali-soluble resin which is a copolymer of hydroxystyrene and styrene consisting of from 60 to 97% by moles of hydroxystyrene units and from 40 to 3% by moles of styrene units, a copolymer of hydroxystyrene and styrene consisting of from 60 to 97% by moles of hydroxystyrene units and from 40 to 3% by moles of styrene units substituted by alkali-insoluble groups for from 5 to 30% of the hydroxyl groups or a polyhydroxystyrene substituted by alkali-insoluble groups for from 3 to 40% of the hydroxyl groups; (B) from 0.5 to 20 parts by weight of an onium salt compound selected from the group consisting of iodonium salt compounds and sulfonium salt compounds, of which the anionic moiety is a fluoroalkyl sulfonate anion as a radiation-sensitive acid-generating agent; and (C) from 3 to 50 parts by weight of an ethyleneurea compound represented by the general formula in which R 1 and R 2 are each a hydroxyl group or an alkoxy group having 1 to 4 carbon atoms and R 3 and R 4 are each a hydrogen atom, a hydroxyl group or an alkoxy group having 1 to 4 carbon atoms, as a crosslinking agent.