US 9,465,291 B2  24  23  -continued  (1-2-14)  The cyclic a,~-unsaturated ketone is reacted with the  organolithium compound or the hydrogenation agent (e.g.,  LiAIH$_{4}$ )  in a solvent (e.g., tetrahydrofuran (THF)) to obtain  the cyclic unsaturated alcohol compound. A (meth)acryloyl  halide, (meth)acrylic acid, or (meth)acrylic anhydride is  reacted with the unsaturated alcohol compound in the pres› ence of a base ( e.g., organic amine) to synthesize the  compound (i).  Examples of the halogen atom represented by X include  a chlorine atom, a bromine atom, and an iodine atom.  Among these, a chlorine atom is preferable.  Examples of the monovalent chain hydrocarbon group  represented by R 2  include those mentioned above in con- nection with the monovalent chain hydrocarbon group rep› resented by R 3 , R 4 , and Rs, and the like.  Examples of the monovalent aromatic hydrocarbon group  represented by R 2  include those mentioned above in con› nection with the monovalent aromatic hydrocarbon group  represented by R 3 , R 4 , and Rs, and the like.  The polymer [A] may include the following structural  units (II) to (VII) and an additional structural unit in addition  to the structural unit  (I). Note that the polymer [A] may  include two or more types of each structural unit. Each  structural unit is described in detail below.  Structural Unit (II)  The structural unit (II) is a structural unit represented by  the following formula (2). When the polymer [A] is used as  the base polymer, the hydrophilicity of the resulting resist  film can be appropriately adjusted by incorporating the  structural unit (II) in the polymer [A]. When the polymer [A]  is used as the water-repellent additive, an improvement in  hydrophobicity can be achieved by incorporating the struc› tural unit (II) that includes a fluorine atom in the polymer  [A], and the dynamic contact angle of the surface of a resist  film formed using the resulting radiation-sensitive resm  composition can be further improved.  Among these, the structural units (I-2-1) to (I-2-8), (I-2- 13),  and (I-2-14) are preferable.  The content of the structural unit  (I) in the polymer [A] is  preferably  10 to 80 mo! %, more preferably 20 to 70 mo! %,  and still more preferably 30 to 60 mo! %, based on the total  structural units included in the polymer [A]. When the  content of the structural unit  (I) is within the above range, a  resist pattern can be formed with more excellent sensitivity,  LWR performance, and resolution.  A monomer compound (i) that produces the structural unit  (I) may be synthesized according to the following scheme,  for example.  In the above scheme, R  1  is a hydrogen atom, a fluorine  atom, a methyl group, or a trifluoromethyl group, R 2  is a  hydrogen atom or a monovalent hydrocarbon group, R 3  is a  hydrogen atom, a monovalent chain hydrocarbon group, a  monovalent alicyclic hydrocarbon group, or a monovalent  aromatic hydrocarbon group, or is bonded to R  $^{6 }$to form an  alicyclic structure together with the carbon atoms respec› tively bonded to R 3  and R 6 , R 4  is a hydrogen atom, a  monovalent chain hydrocarbon group, a monovalent alicy› clic hydrocarbon group, or a monovalent aromatic hydro- carbon group, Rs is a hydrogen atom, a monovalent chain  hydrocarbon group, a monovalent alicyclic hydrocarbon  group, or a monovalent aromatic hydrocarbon group, or is  bonded to R  $^{6 }$to form an alicyclic structure together with the  carbon atoms respectively bonded to Rs and R 6 , R 6  monovalent chain hydrocarbon group, and is bonded to R 3  or Rs to form an alicyclic structure together with the carbon  HO  R2  ~R’  R 2 Li  -- R6  (b)  R5  I  R4  (a)  (c)  RI  (c)  RI  ====<  ====<  C=O  I  -- 1  C=O  I  R3  X  R6  (d)  R5  I  R4  (i)  (2)  wherein R 7  is a hydrogen atom, a fluorine atom, a methyl  group, or a trifluoromethyl group, G is a single bond, an  oxygen atom, a sulfur atom, ----C0-0-, -S0$_{2}$-0- NH-, --CO-NH-, or ---0-CO-NH-, and  W  is a  monovalent chain hydrocarbon group having 1 to 6 carbon  atoms that includes at least one fluorine atom, or a mon- atoms respectively bonded to R$^{3 }$or Rs and R 6 , provided that,  when R 6  and Rs are bonded to each other, R 2  is a hydrogen  atom, and R 3  and R 4  are independently a hydrogen atom, a  monovalent chain hydrocarbon group, a monovalent alicy- clic hydrocarbon group, or a monovalent aromatic hydro› carbon group, or R$^{3 }$and R 4  are bonded to each other to form  an alicyclic structure or an aromatic heterocyclic structure  together with the carbon atoms respectively bonded to R 3  and R 4 ,  or R 4  and Rs are bonded to each other to form an  alicyclic structure or an aromatic heterocyclic structure  together with the carbon atom bonded to R 4  and Rs, and  some or all of the hydrogen atoms of R 2 , R 3 , and R 4  are  optionally substituted with a fluorine atom, X is a halogen  atom, a hydroxyl group, or R$^{2}$COO-, and R 2  is a monova- lent hydrocarbon group. 