NOVELTY - A fluorine-containing diene (1) has specific structure.    USE - For manufacturing fluorine-containing (co)polymer used for resist composition and resist protective film composition used for forming resist pattern (all claimed), ion-exchange membrane, fuel cell, battery material, optical fiber, electronic component, transparent film material, agricultural film, adhesive agent, fiber material, and weather resistance coating material.    ADVANTAGE - The fluorine-containing diene provides fluorine-containing polymer with high transparency with respect to wide wavelength region. The fluorine-containing polymer has high chemical stability and heat resistance. The resist pattern easily formed using the resist composition has excellent sensitivity, resolution, flatness, and heat resistance.    DETAILED DESCRIPTION - A fluorine-containing diene is of formula (1): CF2=CFCF2C(CF3)(OR1)-(CH2)nCR2=CHR3.    R1=H, 20C or less alkyl or (CH2)aCOOR4;    R4=H or 20C or less alkyl;    a=0 or 1;    R2,R3=H or 12C or less alkyl;and    n=0 or 2.    When R1 or R4, and R2 or R3 is alkyl, a portion or whole of hydrogen atoms are optionally substituted by fluorine atom, and have ether property oxygen atom. When n is 0, at least one of R1-R3 excludes H. INDEPENDENT CLAIMS are included for the following: (i) fluorine-containing polymer, which has monomer unit formed by cyclo-polymerizing fluorine-containing diene (1); (ii) manufacture of fluorine-containing polymer; (iii) resist composition, which contains the fluorine-containing polymer, an acid-generating compound, which receives light irradiation and generates an acid, and an organic solvent; (iv) resist protective film composition, which is obtained by dissolving fluorine-containing polymer having monomer unit (M) formed by cyclo-polymerizing fluorine-containing diene of formula (14): CF2=CFCF2C(CF3)(OR1)-(CH2)nCR2=CHR3 or formula (15): CF2=CFCH2CHQ-(CH2)nCR2=CHR3, in a solvent.    R1-R3=same as defined above;    Q=(CH2)bC(CF3)c(R5)dOR1;    b=0-3;    c,d=0-2;    c+d=2;and    R5=H or methyl;    (v) fluorine-containing copolymer, which has the monomer unit (M) and a monomer unit formed by polymerizing vinyl ester group monomer of formula (16): CH2=CHOC(O)R8, where R8 is 8C or less alkyl; (vi) manufacture of fluorine-containing copolymer, which involves co-polymerizing the fluorine-containing diene (14 or 15) and vinyl ester group monomer (16); and (vii) resist pattern formation, which involves forming a resist film on a main surface of a substrate, forming a resist protective film using the resist protective film composition on the resist film, exposing the substrate by liquid immersion lithography, and carrying out alkali image development of the exposed substrate.