Patent ID: 7911048

Claim:
A wiring substrate, comprising: a semiconductor substrate having a through hole; an insulating film provided to cover an upper surface, a lower surface and a first surface of the semiconductor substrate, the first surface corresponding to a side surface of the through hole; a through electrode extending through the through hole, the through electrode including a main body disposed in the through hole, a first projection portion projecting from the insulating film formed on the upper surface of the semiconductor substrate, and a second projection portion projecting from the insulating film formed on the lower surface of the semiconductor substrate, the main body, first projection portion, and the second projection portion being integrally formed, having a constant width, and forming a continuous side surface of the through electrode; a first wiring pattern disposed on an upper surface side of the semiconductor substrate and coupled to the first projection portion of the through electrode, and supported by the first projection portion; and a second wiring pattern disposed on a lower surface side of the semiconductor substrate and coupled to the second projection portion of the through electrode, and supported by the second projection portion, wherein a first air gap is confined by the first wiring pattern, the side surface of the through electrode, and the insulating film formed on the upper surface of the semiconductor substrate, and a second air gap is confined by the second wiring pattern, the side surface of the through electrode, and the insulating film formed on the lower surface of the semiconductor substrate.