content_image/888958.jpg content_image/888955.jpg
wherein R$_{1 }$ is a hydrogen atom, a trifluoromethyl group, a C$_{1 }$ -Cs alkyl group, or C$_{1 }$ -Cs alkoxy group, R$_{2 }$ and R$_{3 }$ are respectively a linear or branched C$_{1 }$-C$_{20 }$alkyl group, an aryl group, a linear or branched C$_{1 }$-C$_{20 }$ perfluoroalkyl group, a benzyl group, or a CcC$_{20 }$ aryl group, R$_{4}$ , Rs and R$_{6 }$ are respectively a hydrogen atom, or a C$_{1 }$-C$_{30 }$alkyl group includ› ing or not including an ether group, an ester group, a carbonyl group, an acetal group, an epoxy group, a nitrile group, or an aldehyde group, R$_{7}$ , R$_{8 }$ and R$_{9 }$ are respectively a hydrogen atom, a methyl group, or a trifluoromethyl group, X$_{2 }$is olefin, vinyl, styrene, or a derivative thereof, a, b, c, d, and e respec- tively satisfy 0.0l~a/(a+b+c+d+e)<0.4; 0.01 <b/(a+b+c+d+ e)<0.3; 0.01 <c/(a+b+c+d+e)<0.3; 0.01 ~d/(a+b+c+d+e) <0.3; 0.0l~e/(a+b+c+d+e)<0.15, and A- is a compound represented as 

wherein X$_{1 }$ is a monocyclic or polycyclic C$_{3}$ -C$_{20 }$hydro› carbon group, a benzyl group, a C$_{6}$-C$_{20 }$aryl group, a C$_{1 }$-C$_{10 }$ alkyl group, a C$_{1 }$-C$_{10 }$alkoxy group, a C$_{1 }$-C$_{10 }$hydroxy alkyl group, or a cyano group, at least one hydrogen atom of the monocyclic or polycyclic C$_{3}$ -C$_{20 }$hydrocarbon group is or is not substituted with an ether group, an ester group, a carbonyl group, an acetal group, a nitrile group, a cyano group, a hydroxy group, a carboxyl group, or an aldehyde group, R is a C$_{1 }$-C$_{10 }$alkyl group, aC$_{1 }$-C$_{10 }$alkoxy group, a nitrogen atom, a sulfur atom, or an oxygen atom, and mis a positive integer ofO to 2. 

The copolymer may be a block copolymer, a random copolymer, or a graft copolymer. The copolymer may be synthesized by a polymerization of monomers including the PAG, and a method of the polymerization is not particularly limited, however, for example, a radical polymerization may be used. As a polymerization initiator of the radical polymer› ization, azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), lauryl peroxide, azobisisocapronitrile, azobisisovale› ronitrile, tert-butyl hydroperoxide, and the like may be used alone or in a combination of two or more thereof. A polymer› ization reaction may be performed by an arbitrary polymer› ization reaction selected from among bulk polymerization, 

<img src='content_image/888958.jpg'>

<img src='content_image/888955.jpg'>

[Chemical formula 2] 

solution polymerization, suspension polymerization, bulk› suspension polymerization, emulsion polymerization, and the like. As a polymerization solvent, at least one polymer- ization solvent selected from benzene, toluene, xylene, halo› genated benzene, diethyl ether, tetrahydrofuran, 1,2-dichlo› roethane, esters, ethers, lactones, ketones, and amides may be used. Non-reaction monomer and by-products remaining in a reaction mixture may be preferably removed by a precipita› tion method performed by means of a solvent, after the poly- merization is completed. 

An amount of the PAG upon the polymerization of the copolymer may rely on an amount of a total solid of the chemically amplified resist composition including the copolymer. Specifically, the copolymer may perform the polymerization using the PAG of about 0.5 to 15 parts by weight with respect to about 100 parts by weight of the total solid of the chemically amplified resist composition. When the amount of the PAG is about 0.5 parts by weight or less with respect to about 100 parts by weight of the total solid of the composition, acid generation may be reduced to thereby reduce a resolution, and a resist pattern including a bottom layer may be not properly generated, that is, formed to be inclined, and when the amount of the PAG is about 15 parts by weight or more with respect to about 100 parts by weight of the same, the acid generation may overly occur to thereby increase in a thickness loss of an upper portion of the resist layer, and a light absorption of the PAG may increase to thereby reduce a transparence of a resin. 

A weight-average molecular weight in terms of polysty› rene measured by gel permeation chromatography (GPC) of the copolymer may be about 500 to 100,000. More specifi- cally, the weight-average molecular weight may be about 3,000 to 30,000 considering coating property of the chemi› cally amplified resist composition, developing property and heat resistance of the resist layer. When the weight-average molecular weight is about 500 or less, the resist pattern may be easily destroyed or deformed, and when the weight-aver› age molecular weight exceeds about 100,000, the resolution of the resist pattern may be reduced. The molecular weight distribution of the copolymer may be about 0.9 to 5, and more particularly, about 1 to 3. The molecular weight distribution of the copolymer may be appropriately adjusted by changing a used amount and reaction time of a radical polymerization initiator. 

As examples of the copolymer according to an exemplary embodiment of the invention, copolymers represented as Chemical formulas 9 to 21 may be given, and the present exemplary embodiments are not limited thereto. 

[Chemical formula 9] 

