▎ 摘　　要

NOVELTY - A carbon film comprises a polyphenylene polymer (I), and has a specific width or a specific shape. USE - Carbon film e.g. graphene nanoribbon is used for electroconductive element and carbon film element (all claimed). ADVANTAGE - The carbon film having specific width/shape can be manufactured by simple process. DETAILED DESCRIPTION - A carbon film comprises a polyphenylene polymer of formula (I), and has a specific width or a specific shape. R1-R8=H, halo, alkyl or aryl; n=0-5; X=groups chosen from group of formulae (i) and (ii); one of X1-X3 and Y1-Y3=1C or more ether or optionally substituted acyloxy and other being H;and Q1-Q6=H, halo or monovalent organic group. Q1 to Q6 are optionally coupled to form ring. An INDEPENDENT CLAIM is included for carbon film element, which has a support substrate, a gate insulating layer on the substrate, a carbon film layer consisting of the carbon film on the gate insulating layer, electrode (a) formed adjacent to the carbon film layer, and electrode (b).