| 摘要 |
PROBLEM TO BE SOLVED: To provide a wiring board where heat radiation as the wiring board such as a power module is increased and at the same time the thermal resistance of the wiring board is reduced. SOLUTION: In the silicon nitride wiring board where a wiring circuit layer 2 is provided on one surface of an insulation substrate 1 that is made of ceramics with silicon nitride as a main constituent, and a heat sink 4 is applied to the other surface, a via formation layer 1b where a plurality of via conductors 6 in that a conductor that is mainly made of copper is filled are arranged is provided at the other surface side of the insulation substrate 1, the via conductor 1b is thermally connected to the heat sink 4, and the thickness of the via formation layer 1b in the insulation substrate 1 is set to 30-80% of the entire insulation substrate. |
