Chemically amplified resist composition containing low molecular weight additives

A chemically amplified positive photoresist composition comprising:

• a multi-component copolymer represented by the formula 1 and having a polystyrene-reduced weight average molecular weight (Mw) of 3,000 to 50,000 and a molecular weight distribution (Mw/Mn) of 1.0 to 3.0;
• a low molecular weight additive represented by the formula V;
• an acid generator;
• and
• a solvent,
• [Formula 1]
• wherein X and Y independently comprise a repeating unit selected from the group consisting of monomers represented by the formulas (II), (III) and (IV):
• wherein R1 is a hydrogen atom, a normal, branched, monocyclic or polycyclic alkyl group having 1 to 20 carbon atoms, or a normal, branched, monocyclic or polycyclic alkyl carbonyl group having 1 to 20 carbon atoms, including acetyl group, t-butyl oxycarbonyl group, cyclohexane carbonyl group, adamanthane carbonyl group and bicyclo[2,2,1]heptane methyl carbonyl group;
• R2 is a hydrogen atom, a hydroxyl group, a carboxyl group, an alkyl or alkoxy group having 1 to 20 carbon atoms, an alkyl or alkoxy group containing a hydroxyl or carboxyl group, a normal or branched alkyloxycarbonyl or alkoxyalkylcarbonyl group, or a monocyclic or polycyclic alkyloxycarbonyl group;
• R3 is a hydrogen atom, or a normal, branched, monocyclic or polycyclic alkyl group having 1 to 20 carbon atoms, including methyl group, ethyl group, t-butyl group, isopropyl group, adamanthyl group, and bicyclo[2,2,1]heptane methyl group;
• and l, m, n and o are independently a number representing the repeating unit of the polymer and satisfying 0≦l/(l+m+n+o)≦0.5, 0≦m/(l+m+n+o)≦0.5, 0≦n/(l+m+n+o)≦0.35, 0.4≦o/(l+m+n+o)≦0.6, and 0.15≦(l+m)/(l+m+n+o)≦0.5,
• [Formula 2]
• wherein R4 and R5 are the same as or different from each other and each represents a normal, branched, monocyclic or polycyclic alkyl group having 1 to 20 carbon atoms;
• and R6 is a hydrogen atom, or a normal, branched, monocyclic or polycyclic alkyl or alkoxy group having 1 to 20 carbon atoms.