Patent ID: 7566834

Claim:
A wiring board comprising: a base insulating film which has a thickness of 20 to 100 μm and in which via holes are formed; a lower wiring which is formed on the under surface of said base insulating film and which is connected to said via holes; and an upper wiring which is formed on said base insulating film and which is connected to said lower wiring through said via holes, said base insulating film being composed of a heat-resistant resin, which has a glass-transition temperature of 150° C. or higher and which contains reinforcing fibers made of glass or aramid, and having the following physical properties (1) to (6) when an elastic modulus at a temperature of T° C. is given as D T (GPa), and when a breaking strength at a temperature of T° C. is given as H T (MPa) (1) A coefficient of thermal expansion in the direction of thickness thereof is 90 ppm/K or less (2) D 23 ≧5 (3) D 150 ≧2.5 (4) (D −65 /D 150 )≦3.0 (5) H 23 ≧140 (6) (H −65 /H 150 )≦2.3.