| 摘要 |
PROBLEM TO BE SOLVED: To provide means for increasing a wiring density with inhibition of protrusion of a brazing filler material in a direction toward one principal surface of an insulation substrate, and with increase in a distance between distribution lines and in a creeping distance, and without decrease of a dielectric strength voltage.SOLUTION: A wiring board comprises: an insulation substrate 1; metal circuit boards 3 bonded to one principal surface of the insulation substrate 1 via brazing filler material layers 2; and a heat sink 4 bonded to the other principal surface of the insulation substrate 1. The insulation substrate 1 includes recesses 1a formed on the one principal surface each along an outer edge of the metal circuit board 3, and the brazing filler material layer 2 extends from the outer edge of the metal circuit board 3 to inside the recess 1a. A distance between distribution lines is increased and a dielectric strength voltage is more unlikely to decrease than the case where the brazing filler material layer 2 is formed on the one principal surface of the insulation substrate 1 so as to protrude from an outside end of the metal circuit board 3 in a direction toward the one principal surface of the insulation substrate 1, so that a wiring density can be increased. |
