99  US 7,511,179 B2  100  The novel fluorine-containing polymer of the present  invention possesses dry etching resistance higher than that of  polymers prepared using norbomene and transparency  thereof even in a vacuum ultraviolet region is excellent as  compared with polymers prepared using norbornene.  wherein Rf4 is a perfluoroalkylene group which has 1 to 10  carbon atoms and may have ether bond;  R $^{4 }$is hydrogen atom  or an alky 1 group having 1 to 10 carbon atoms.  3.  The fluorine-containing unsaturated cyclic compound of  claim  1,  wherein in the formula (1 )(a),  Z $^{3 }$is represented by the  formula:  Also the copolymer obtained by copolymerizing a fluo› roolefin with the novel unsaturated compound having a  monocyclic structure of the present invention which has an  acid-reactive functional group directly bonded to a ring and  partly contains fluorine possesses an excellent dry etching  resistance and high transparency when used for a resist.  What is claimed is:  1.  A fluorine-containing unsaturated cyclic compound rep- resented by the formula (l)(a):  wherein  R: $^{15 }$is an alkylene group which has 1 to 5 carbon  atoms and may have ether bond or a fluorine-containing alky› lene group which has 1 to 5 carbon atoms and may have ether  bond; RF is a fluorine-containing alkyl group which has 1 to  10 carbon atoms and may have ether bond; RF is hydrogen  atom, an alkyl group having 1 to 10 carbon atoms or a fluo› rine-containing alkyl group which has 1 to 10 carbon atoms  and may have ether bond; nl 2 is 0 or 1.  4.  The fluorine-containing unsaturated cyclic compound of  claim  3,  wherein Z $^{3 }$is represented by the formula:  wherein  Z $^{3 }$are the same or different and each is  -RF-Z , in  which Z 4  is at least one functional group selected from the  group consisting of OH group, COOH group, a derivative of  carboxylic acid group and a functional group protected by a  protective group which can convert the functional group to  OH group by reaction with an acid; Rf $^{3 }$is a fluorine-contain› ing alkylene group which has 1 to 30 carbon atoms and may  have ether bond; nl 1 is an integer of from 1 to 4.  2.  The fluorine-containing unsaturated cyclic compound of $_{55 }$ claim  1,  wherein in the formula (1 )(a),  Z $^{3 }$is represented by the  formula:  wherein RF and R:f6 are as defined in said formula; n13 is 0 or  an integer of from 1 to 5; n14 is 0 or 1.  5.  The fluorine-containing unsaturated cyclic compound of  claim  3,  wherein  RF  and R:f6 are the same or different and  each is a perfluoroalkyl group having 1 to 5 carbon atoms.  *  *  *  *  *  TABLE 2-continued  Fluorine-containing compound  having OH group  (1)  (2)  Model structure  i\.H  pKa  H  H  116.3  11.5  ,~cc,  F  OH  CH$_{2}$=CHCH$_{2}$C(CF$_{3}$)oOH  CF$_{2}$=CF-----C(CF $_{3}$)oOH  CF$_{3}$CH(CF$_{3}$)---0H  CH$_{2}$=CF-----C(CF$_{3}$)oOH  CH2=CFCF2OCFCF2OCFCH2OH  CH$_{2}$=CHCH$_{2}$C(CF$_{3}$)oOH  CH$_{2}$=CHCH$_{2}$C(CF$_{3}$)oOH  CH$_{2}$=CHCH$_{2}$C(CF$_{3}$)oOH  CH$_{2}$=CHCH$_{2}$C(CF$_{3}$)oOH  HCF2OCFCH2OH  74.2  9.6  13.2  7.1  50.4  9.3  38.7  8.0  122.3  12.6  I  I  I  CF3  CF3  CF3  H  H  (Z  )nil  -Rf’-----COOR 14  Rf5  I  --(CH2)n13-(OCH2)n14-C-OH  ~  Rf 5  I  --(R 15 )n12-C-OH  !iu  (l)(a) 