8  Jun.  27,  2013  US 2013/0164674 Al  consisting of a hydrogen atom, an alkyl group having 1 to 10  carbon atoms, an alkenyl group, a haloalkyl group having 1 to  10 carbon atoms, an aralkyl group having 6 to 30 carbon  atoms, an aryl group having 6 to 30 carbon atoms, and com› binations thereof, while X$_{1 }$ and X$_{2}$, or Y$_{1 }$ and Y$_{2 }$ may be  joined together to form a saturated or unsaturated hydrocar› bon ring having 3 to 30 carbon atoms;  [0044]  X$_{3}$ ,  X$_{4}$ ,  X$_{5}$ ,  Y$_{3}$ ,  Y$_{4 }$ and Y$_{5 }$ each independently rep› resent any one selected from the group consisting of a hydro› gen atom, an alkyl group having 1 to 30 carbon atoms, a  halogen group, an alkoxy group having 1 to 30 carbon atoms,  an aryl group having 6 to 30 carbon atoms, a thiophenoxy  group, a thioalkoxy group having 1 to 30 carbon atoms, an  alkoxycarbonylalkoxy group having 1 to 20 carbon atoms,  and combinations thereof;  [0045]  Z  of the anion moiety represents OSO$_{2}$CF$_{3}$ ,  OSO$_{2}$C$_{4}$ F$_{9}$ ,  OSO$_{2}$C$_{8}$F $_{17}$, N(CF 3 ) 2 ,  N(C$_{2}$F  5 ) 2 ,  N(C$_{4}$F$_{9}$ ) 2 ,  C(CF  3 ) 3 ,  C(C$_{2}$F  5 ) 3 ,  C(C$_{4}$F$_{9}$ ) 3 ,  or the following formula (20):  [0046]  wherein V$_{1 }$ and V$_{2 }$ each independently represent a  halogen atom;  [0047]  W $_{1 }$ represents -(C=O)- or -(SO$_{2}$)-;  [  0048]  W $_{2 }$ represents an alkanediy 1 group having 1 to 10  carbon atoms;  [0049]  W $_{3 }$ represents any one selected from the group con› sisting of a cycloalkyl group having 3 to 30 carbon atoms, an  aryl group having 6 to 30 carbon atoms, an aralkyl group  having 7 to 30 carbon atoms, an aryloxy group having 6 to 30  carbon atoms, an arylthio group having 6 to 30 carbon atoms,  a heterocyclic group having 5 to 30 carbon atoms, and com› binations thereof;  [0050]  W $_{4 }$ represents any one selected from the group con› sisting of a hydrogen atom, a halogen group, an alkyl group  having 1 to 10 carbon atoms, an alkoxy group having 1 to 10  carbon atoms, a haloalkyl group having 1 to 10 carbon atoms,  an alkylthio group having 1 to 10 carbon atoms, an aryl group  having 6 to 30 carbon atoms, and combinations thereof;  [0051]  o represents an integer of 0 or 1; and  [0052]  p represents an integer from Oto 2.  [0053]  The acid generator may be included in an amount of  0.3 to 10 parts by weight relative to l00parts by weight of the  solids content in the resist composition.  [0054]  The resist composition may further include addi› tives selected from the group consisting of an alkali dissolu› tion inhibitor, an acid diffusion inhibitor, a surfactant, and  mixtures thereof.  [0055]  According to another aspect of the present inven› tion, there is provided a method for forming a resist pattern,  which includes a step of applying the resist composition  described above on a substrate and thereby forming a resist  film; a step of heat treating the resist film and then exposing  the resist film into a predetermined pattern; and a step of  developing the exposed resist pattern.  [0056]  The exposure process may be carried out by using a  light source selected from the group consisting of a KrF  excimer laser, an ArF excimer laser, an extreme ultraviolet  laser, X-radiation, and an electron beam.  [0057]  The details of other embodiments of the present  invention will be disclosed in the detailed description of the  invention given below.  [0058]  The acrylic monomer according to the present  invention is useful as a monomer for forming a base polymer  of a resist composition, particularly a positive chemically  amplified photoresist composition, which is less dependent  on the substrate at the time of resist patterning, and is capable  of enhancing the transparency, contrast, sensitivity, resolu› tion and developability of the resist.  [0059]  The polymer according to the present invention con› taining a repeating unit derived from the monomer described  above is useful for the formation of a fine pattern using  various radiations such as far-ultraviolet radiation of a KrF  excimer laser, an ArF excimer laser or a F$_{2 }$ excimer laser;  X-radiation such as synchrotron radiation; and charged par› ticle beams such as EUV.  [0060]  Furthermore, the resist composition according to  the present invention containing the polymer described above  exhibits  excellent adhesiveness,  storage  stability  and  enhanced line width roughness, and exhibits excellent reso› lution in both C/H patterns and LIS patterns.  [0061]  Also, since the resist composition has excellent pro› cess window, an excellent pattern profile can be obtained  regardless of the type of the substrate, and improved contrast  is exhibited.  BRIEF DESCRIPTION OF THE DRAWINGS  [0062]  FIG.  1  is a proton nuclear magnetic resonance (1H› NMR (CDC1$_{3}$ ,  400 MHz)) spectrum of the intermediate (iii)  produced in Step 1 of Synthesis Example 1 for the acrylic  monomer.  [0063]  FIG.  2  is a $^{1}$H-NMR(CDC1$_{3}$ ,  400MHz) spectrum of  the compound of formula (1 a) produced in Step 2 of Synthesis  Example 1 for the acrylic monomer.  [0064]  FIG.  3  is a $^{1}$H-NMR(CDC1$_{3}$ ,  400MHz) spectrum of  the polymer (16) produced in Intermediate Synthesis  Example 1.  [0065]  FIG.  4  is a $^{1}$H-NMR(CDC1$_{3}$ ,  400MHz) spectrum of  the polymer (15) produced in Polymer Synthesis Example 2.  DETAILED DESCRIPTION OF THE INVENTION  [0066]  Hereinafter, embodiments of the present invention  will be described in detail. However, these embodiments are  only for illustrative purposes, and the present invention is not  intended to be limited thereto. The present invention is to be  defined only by the scope of the claims that will be described  below.  [0067]  Unless particularly stated otherwise in the present  specification, the term "halogen atom" means any one  selected from the group consisting of fluorine, chlorine, bro› mine and iodine.  [0068]  Unless particularly stated otherwise herein, the pre› fix "hetero-" means that one to three carbon atoms are sub› stituted by heteroatoms selected from the group consisting of  nitrogen (N), oxygen (0), sulfur (S) and phosphorus (P). For  example, a heteroalkyl group means that one to three carbon  atoms among the carbon atoms of an alkyl group are substi› tuted by heteroatoms.  [0069]  Unless particularly stated otherwise herein, the term  "alkyl group" means a linear or branched alkyl group having  [Chemical Formula 20]  0  V1  II  I  H2  -o- 11 - 1 -c -O-W1-(W2)0-r:,;v$_{3}$ )p-w 4  0  V2 