Photoresist cross-linker and photoresist composition comprising the same

A photoresist composition which comprises (i) a photoresist polymer, (ii) at least one cross-linking substance selected from the group consisting of a monomer represented by the following Chemical Formula 1, its homopolymer, its copolymers, and mixtures thereof:

• wherein, R1 and R2 individually represent unsubstituted straight or branched C1-10 alkyl, straight or branched C1-10 alkyl substituted with at least one ester group, straight or branched C1-10 alkyl substituted with at least one ketone group, straight or branched C1-10 alkyl substituted with at least one carboxylic acid group, straight or branched C1-10 alkyl substituted with at least one acetal group, straight or branched C1-10 alkyl substituted with at least one hydroxyl group, straight or branched C1-10 alkyl substituted with at least one hydroxyl group and one ester group, straight or branched C1-10 alkyl substituted with at least one hydroxyl group and one ketone group, straight or branched C1-10 alkyl substituted with at least one hydroxyl group and one carboxylic acid group, and straight or branched C1-10 alkyl substituted with at least one hydroxyl group and one acetal group;
• and R3 represents hydrogen or methyl;
• (iii) a photoacid generator;
• and (iv) an organic solvent.