Circuit board and semiconductor device using the same

Abstract

A base plate is made of a material that is lower in thermal expansion coefficient than a wiring layer, to thereby set the thermal expansion coefficient of a surface of the wiring layer lower than the thermal expansion coefficient of the material of the wiring layer. The thermal expansion coefficient of the surface of the wiring layer can be set to be suitable for a semiconductor element and other electronic parts mounted on the surface of the wiring layer, that is, set closer to the thermal expansion coefficient of the electronic parts by choosing a glass transition temperature Tg of an insulating resin layer appropriately.

Dependencies are inferred from the claim text.