92  US 8,691,490 B2  91  The position of substitution in the hydroxyvinylnaphtha› lene represented by the foregoing general formula (14) is  arbitrary, but 6-hydroxy-2-vinylnaphthalene, 4-hydroxy-1- vinylnaphthalene and the like may be used, while especially  6-hydroxy-2-vinylnaphthalene is preferably used.  The polymer of the present invention can further include, in  addition to a repeating unit represented by the foregoing  general formula ( 4) or (5) and a repeating unit represented by  the foregoing general formulae (11) to (15), a repeating unit  represented by the foregoing general formulae (6) to (10).  Especially, preferably usable is a polymer including a repeat› ing unit represented by the foregoing general formula (6)  among these repeating units represented by the formulae (6)  to (10).  The polymer including a sulfonium salt of the present  invention having a polymerizable functional group as a  repeating unit and including any one or more kinds of repeat- ing units represented by the foregoing general formulae (11)  to (15) may contain a repeating unit derived from a monomer  having a carbon-carbon double bond other than those  described above. For example, it may contain a repeating unit  derived from substituted acrylic acid esters such as methyl  methacrylate, methyl crotonate, dimethyl maleate, and dim› ethyl itaconate; unsaturated carboxylic acids such as maleic  acid, fumaric acid and itaconic acid; cyclic olefins such as  norbornene, a norbornene derivative and a tetracyclo  [ 6 .2.  1.  1  3  • $^{6 }$.02 •  7 ] dodecene derivative, norvornadiene; unsatur- ated acid anhydrides such as itaconic anhydride; styrene,  acenaphthylene, vinylnaphthalene, and other monomers.  Meanwhile, the weight-average molecular weight of the  polymer of the present invention is preferably 1,000 to 500,  000, or more preferably 3,000 to 100,000. The weight-aver› age molecular weight is preferably in this range, because  there is no possibility that the etching resistance is extremely  deteriorated and the difference in dissolution rates before and  after the exposure cannot be secured and thereby resolution is  deteriorated. As to the measurement method of the molecular  weight, a gel permeation chromatography (GPC) with the  polystyrene conversion and a light scattering method may be  mentioned.  In the polymer of the present invention, the preferable ratio  of each repeating unit derived from respective monomers can  be made, for example, in the following ranges  (% by mole),  but is not limited to them.  H  H  H  H  H  H  H  H  H  :>---<  \  H  H  H  :>---<  H  H  H  -f  H  H  H  H  H  H  H  H  -continued  -continued 