Polyimide film, high-frequency circuit substrate, and flexible electronic device substrate

A polyimide film comprising a polyimide prepared by reacting a tetracarboxylic acid component with a diamine component containing 4,4″-diamino-p-terphenyl, wherein the polyimide film has a glass transition temperature of 300° C. or more, a coefficient of linear expansion in the temperature range of 50° C. to 200° C. of 6 ppm/K or less, and any one of the following (A) to (C) applies:

• (A) the tetracarboxylic acid component includes 10 to 30 mol % of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) and 70 to 90 mol % of pyromellitic dianhydride (PMDA) in the total tetracarboxylic acid components, and the diamine component includes 50 mol % or more of 4,4″-diamino-p-terphenyl (DATP) in the total diamine components,
• (B) the tetracarboxylic acid component includes 70 to 90 mol % of pyromellitic dianhydride (PMDA) and 30 to 10 mol % of oxydiphthalic dianhydride (ODPA) in the tetracarboxylic acid components, and the diamine component includes 50 mol % or more of 4,4″-diamino-p-terphenyl (DATP) in the total diamine components,
• and
• (C) the tetracarboxylic acid component includes 10 to 30 mol % of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) and 70 to 90 mol % of pyromellitic dianhydride (PMDA) in the total tetracarboxylic acid components, and the diamine component includes 10 to 70 mol % of 4,4″-diamino-p-terphenyl (DATP) and 90 to 30 mol % of p-phenylenediamine (PPD) in the total diamine components.