Patent ID: 7696613

Claim:
A multilayered wiring substrate comprising: wiring layers and insulating layers which are stacked in predetermined number to form a multilayer structure, wherein at least one of the wiring layers is formed as a reinforcing wiring layer whose thickness is greater than 35 μm to less than 70 μm, wherein the thickness of a said wiring layer other than the reinforcing wiring layer is 10 μm to 20 μm, wherein the thickness of a said insulating layer, which is measured between a said wiring layer on the top of that said insulating layer and a said wiring layer on the bottom of that said insulating layer, is 30 μm to 40 μm, and wherein the thickness of the reinforcing wiring layer is larger than that of the other wiring layers, and a ratio (T 1 /T 2 ) of the reinforcing wiring layer to the insulating layer is set to 1≦(T 1 /T 2 )≦5, where T 1 is a thickness of the reinforcing wiring layer and T 2 is a thickness of the insulating layer.