| abstract |
In a semiconductor device, a wiring layer as the uppermost layer of a package substrate is made of an insulating material having a Young's modulus of not more than 1 GPa and an elongation at break of not less than 50% at a temperature from 10˚C to 30˚C. This insulating material contains a reactive elastomer which reacts with an epoxy resin or a curing agent for epoxy resins, an epoxy resin, a curing agent for epoxy resins, and a crosslinked styrene butadiene rubber having a polar group such as a hydroxyl group or carboxyl group and a double bond in its structure. Consequently, there can be obtained a semiconductor device having high connection reliability against temperature cycles and comprising a wiring substrate wherein high adhesion is attained between an insulating layer and an electroless copper plating layer. |