Wiring board and semiconductor device excellent in folding endurance

摘要

A wiring board with folding endurance includes an insulating film and a copper-containing wiring pattern on a surface of the insulating film, and includes an insulating resin coating layer formed on the wiring pattern such that terminals are exposed. The wiring board has any of the constitutions (A), (B), (C) and (D) below. (A) The wiring pattern includes copper particles having a mean crystal particle diameter in the range of from 0.65 to 0.85 mum as determined by EBSP; not more than 1% of the volume of the wiring pattern is accounted for by copper crystal particles having a particle diameter of less than 1.0 mum as determined by EBSP; and copper crystal particles that are [100] oriented in the longitudinal direction of a lead of the wiring pattern account for from 10 to 20% of the volume of the wiring pattern as determined by EBSP. (B) The insulating film is formed of a polyimide film having a tensile strength within the range of from 450 to 600 MPa and a Young's modulus within the range of from 8500 to 9500 MPa. (C) The insulating film is formed of a polyimide film having a thickness of from 10 to 30 mum. (D) The insulating resin coating layer has a thickness of from 50 to 150% relative to the thickness of the insulating film.