Photoresist composition and a method for forming a fine pattern using the same

A photoresist composition, comprising:

• a photosensitive polymer including a polymer chain and a first functional group coupled to the polymer chain, and a photoacid generator, wherein:
• the photoacid generator generates acid ions (H+) when the photoacid generator is exposed to light, and
• the first functional group is convertible into a second functional group by a de-protection reaction using the acid ions (H+) as a catalyst, wherein the second functional group has a structure represented by the following Chemical Formula 8,
• where R1 is one of an alkyl group having a carbon number of 1 to 20 and an aryl group having a carbon number of 1 to 20, and R2 is one of —H, —F, —Cl, —Br, an alkyl group having a carbon number of 1 to 20, and an aryl group having a carbon number of 1 to 20, and wherein the polymer is hydrophilic when it contains the first functional group and hydrophobic when the first functional group is converted into the second functional group, and
• wherein the photosensitive polymer includes a structure represented by the following Chemical Formula 2 or the following Chemical Formula 3,
• where n is an integral number ranging from 1 to 1,000,000, R3 is one of —H and CH3, and R is represented by the following Chemical Formula 4,
• where R1 is one of an alkyl group having a carbon number of 1 to 20 and an aryl group having a carbon number of 1 to 20, and R2 is one of —H, —F, —Cl, —Br, an alkyl group having a carbon number of 1 to 20, and an aryl group having a carbon number of 1 to 20.