Low dielectric constant, low coefficient of linear thermal expansion, high transparency, and a polyimide having both a high glass transition temperature that precursor

摘要

PROBLEM TO BE SOLVED: To provide a method for producing practically useful polyimide film having a combination of low dielectric constant, low coefficient of linear thermal expansion, high transparency, high glass transition temperature and adequate toughness, and to provide a precursor of the polyimide film.;SOLUTION: The polyimide precursor (polyamic acid) is represented by the formula(1) (wherein, A is a bivalent aromatic group, its coupling scheme is para-linkage, or A is a bivalent aliphatic group, its coupling scheme is 1,4-linkage; and X is 0.1-1). The method for producing the polyimide film comprises carrying out a cyclization reaction of the precursor. The polyimide film thus obtained has a dielectric constant of lower than 2.7, a coefficient of linear thermal expansion of lower than 30 ppm/K, a transmittance of i-beam (365 nm) of high-pressure mercury lamp of ≥80% (i.e. colorless), a glass transition temperature of ≥300°C and adequate toughness.;COPYRIGHT: (C)2006,JPO&NCIPI