| 摘要 |
A circuit substrate having an insulating layer comprising a polyimide resin on a metal foil substrate, wherein the polyimide resin is a polyimide resin obtained by the reaction of (A) aromatic diamines comprising (a) 1,3-bis(4-aminophenoxy)benzene and (b) 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl and (B) aromatic tetracarboxylic acid dianhydrides comprising (a) 3,4,3',4'-biphenyltetracarboxylic acid dianhydride and (b) 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride. The circuit-formed substrate has a desired circuit comprising a conductive layer on the circuit substrate. The polyimide resin has a low hygroscopic property and thus the substrate is excellent in the dimensional stability and does not cause warping even when the humidity in the environmental atmosphere is changed.
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