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[0048] that undergoes free radical polymerization will afford a polymer having a repeat unit: 

<img src='content_image/933503.jpg'>

[0049] where P, Q, S, and T independently can represent, but are not limited to, H, F, Cl, Br, an alkyl group containing 1 to 14 carbon atoms, aryl, aralkyl group containing 6 to 14 carbon atoms or a cycloalkyl group containing 3 to 14 carbon atoms. 

[0050] If only one ethylenically unsaturated compound undergoes polymerization, the resulting polymer is a homopolymer. If two or more distinct ethylenically unsat› urated compounds undergo polymerization, the resulting polymer is a copolymer. 

[0051] Some representative examples of ethylenically unsaturated compounds and their corresponding repeat units are given below: 

<img src='content_image/933504.jpg'>

[0052] In the sections that follow, the photoresist compo› sitions of this invention are described in terms of their component parts. 

[0053] The photoresists of this invention comprise a fluo› rine-containing copolymer comprising a repeat unit derived from at least one ethylenically unsaturated compound char› acterized in that at least one ethylenically unsaturated com› pound is polycyclic and at least one ethylenically unsatur› ated compound contains at least one fluorine atom covalently attached to an ethylenically unsaturated carbon atom. Representative ethylenically unsaturated compounds that are suitable for the fluorine-containing copolymers of this invention include, but are not limited to, tetrafluoroet› hylene, chlorotrifluoroethylene, hexafluoropropylene, trif› luoroethylene, vinylidene fluoride, vinyl fluoride, perfluoro› (2,2-dimethyl-1,3-dioxole ), perfluoro-(2-methylene-4- methyl-1,3-dioxolane, CF$_{2}$=CFO(CF$_{2}$),CF=CF$_{2}$ , where t is 1 or 2, and RfOCF=CF$_{2 }$ wherein Rf is a saturated 

fluoroalkyl group of from 1 to about 10 carbon atoms. The fluorine-containing copolymers of this invention can be comprised of any integral number of additional fluorine› containing comonomers, which include, but are not limited to, those listed supra. Preferred comonomers are tetrafluo› roethylene, chlorotrifluoroethylene, hexafluoropropylene, trifluoroethylene and RfOCF=CF$_{2}$ , wherein Rf is a satu› rated fluoroalkyl group of from 1 to about 10 carbon atoms. More preferred comonomers are tetrafluoroethylene, chlo› rotrifluoroethylene, hexafluoropropylene, and RfOCF=CF$_{2}$ , wherein Rf is a saturated perfluoroalkyl group of from 1 to about 10 carbon atoms. Most preferred comono› mers are tetrafluoroethylene and chlorotrifluoroethylene. 

[0054] Representative comonomers having structure H include, but are not limited to: 

<img src='content_image/933505.jpg'>

[0055] Representative comonomers having structure I include, but are not limited to: 

<img src='content_image/933506.jpg'>

[0056] Representative comonomers having structure J include, but are not limited to: 

<img src='content_image/933508.jpg'>

[0057] Representative comonomers having structure K include, but are not limited to: 

<img src='content_image/933509.jpg'>

