Brush polymer, photoresist composition including the same, and method of manufacturing integrated circuit device

A photoresist composition, comprising:

• a brush polymer for a photoresist, the brush polymer including a core and a plurality of side polymer chains, the plurality of side polymer chains being bonded to the core and extending from the core to form a bottle-brush polymer or a star-brush polymer, together with the core;
• a chemically amplified polymer;
• a photoacid generator (PAG);
• and
• a solvent,
• wherein:
• each of the plurality of side polymer chains includes a first repeating unit represented by Formula 1 and a second repeating unit represented by Formula 2:
• in Formulae 1 and 2,
• R1 is a hydrogen atom, an unsubstituted methyl group, a fluorine atom, or a trifluoromethyl group,
• R2 is a C3 to C30 fluoroaliphatic group including a hydroxyl group,
• R3 is a hydrogen atom, an unsubstituted methyl group, a fluorine atom, or a trifluoromethyl group, and
• R4 is a C2 to C20 organic group including an oxygen atom,
• wherein the first repeating unit represented by Formula 1 is different than the second repeating unit represented by Formula 2, and
• wherein each of the plurality of side polymer chains has a terminal group distal to the core.

A method of manufacturing an integrated circuit device, the method comprising:

• forming a photoresist film on an underlying film by using a photoresist composition that includes:
• a brush polymer, the brush polymer including a core and a plurality of side polymer chains, the plurality of side polymer chains being bonded to the core and extending from the core to form a bottle-brush polymer or a star-brush polymer, together with the core,
• a chemically amplified polymer,
• a photoacid generator (PAG), and
• a solvent;
• forming a surface-modified photoresist film having a hydrophilic surface portion, the hydrophilic surface portion being formed by segregating the brush polymer from the chemically amplified polymer in the photoresist film and distributing the brush polymers at a surface of the photoresist film, which is distal to the underlying film;
• generating an acid from the PAG by exposing a first area of the surface-modified photoresist film, which includes a portion of the hydrophilic surface portion, and deprotecting the chemically amplified polymer with the acid;
• pre-wetting the hydrophilic surface portion of the exposed first area of the surface-modified photoresist film with deionized water;
• removing the exposed first area of the surface-modified photoresist film by using a developer to form a photoresist pattern including a non-exposed area of the surface-modified photoresist film;
• and
• processing the underlying film by using the photoresist pattern,
• wherein:
• each of the plurality of side polymer chains includes a first repeating unit represented by Formula 1 and a second repeating unit represented by Formula 2,
• in Formulae 1 and 2,
• R1 is a hydrogen atom, an unsubstituted methyl group, a fluorine atom, or a trifluoromethyl group,
• R2 is a C3 to C30 fluoroaliphatic group including a hydroxyl group,
• R3 is a hydrogen atom, an unsubstituted methyl group, a fluorine atom, or a trifluoromethyl group, and
• R4 is a C2 to C20 organic group including an oxygen atom,
• wherein the first repeating unit represented by Formula 1 is different than the second repeating unit represented by Formula 2, and
• wherein each of the plurality of side polymer chains has a terminal group distal to the core.