| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit board with high reliability, capable of suppressing generations of cracks in an insulating layer.SOLUTION: A metal base circuit board comprises: a metal substrate; an insulating layer formed on the substrate; and a conductive circuit layer formed on the insulating layer. The insulating layer contains Cu as a main component, and is formed of epoxy resin composition obtained by mixing epoxy resin, hardening agent and an inorganic filler. The epoxy resin composition satisfies that a crack resistance index &Sgr;≤0.025 ( the &Sgr;is defined by E×|α-α|×(Tg-25)/F, the Eis a tensile elasticity of the epoxy resin composition at 25°C, the αis a coefficient of linear expansion of the conductive circuit layer at 25°C, the αis a coefficient of linear expansion of the epoxy resin composition at 25°C, the Tg is a glass transition point of the epoxy resin composition, and the F is a tensile breaking strength of the epoxy resin composition at 25°C.) |
