Patent ID: 8138424

Claim:
A wiring substrate, comprising: (i) a wiring forming region in which wiring layers and insulating layers are alternately stacked; (ii) an outer periphery region around the wiring forming region; and (iii) a solid reinforcing structural body having (a) a first reinforcing member continuously extending along said outer periphery region, and (b) a second reinforcing member extending in a thickness direction and being engaged with the first reinforcing member, wherein said first reinforcing member is composed of reinforcing patterns having a multilayer structure and continuously extending within planes of respective insulating layers, and being formed along each side of said wiring substrate, said second reinforcing member is composed of reinforcing pillars buried in said insulating layer sandwiched between said reinforcing patterns of different layers, said reinforcing patterns and said reinforcing pillars are bonded together to form the solid reinforcing structural body and formed so as to surround said wiring forming region, one surface of said wiring substrate is a mounting surface of an electronic component, another surface of said wiring substrate is a mounting surface of an external device, and the first reinforcing member and the second reinforcing member are electrically separated from the wiring layers in the wiring forming region.