Patent ID: 8921703

Claim:
A circuit board, comprising: a core unit comprising: a first polyimide layer having a first surface and a second surface opposite to each other; a first adhesive layer disposed on the first surface; a second adhesive layer disposed on the second surface; a first conductive layer disposed on the first adhesive layer; and a second conductive layer disposed on the second adhesive layer; and a first lamination unit disposed at a first side of the core unit and comprising: a second polyimide layer having a third surface and a fourth surface opposite to each other; a third adhesive layer disposed on the third surface; a fourth adhesive layer disposed on the fourth surface and bonded to the first conductive layer; and a third conductive layer disposed on the third adhesive layer, wherein the first adhesive layer, the second adhesive layer, the third adhesive layer and the fourth adhesive layer all have a glass transition temperature between 140° C. and 160° C.