| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a wiring board which has electric wirings on at least one surface and is mounted with a heat generating component so that heat radiation characteristics can be improved and adhesiveness between a metal layer and a resin insulating layer can also be improved by reducing thermal stress of the resin insulating layer due to a difference in coefficient of thermal expansion between a first metal layer 3 and a third metal layer 6 even when the difference in coefficient of thermal expansion is large. <P>SOLUTION: A first metal layer 3 of≥0.5 mm in thickness, a second metal layer 5, and a third metal layer 7 of≥1 mm in thickness are arranged in this order, and the first metal layer 3 and the second metal layer 5 are united together with a conductive adhesive layer. The second metal layer 5 and the third metal layer 7 are united together with a resin insulating layer 6. Representing the coefficient of thermal expansion of the first metal layer 3 asα1, the coefficient of thermal expansion of the second metal layer 5 asα2, and the coefficient of thermal expansion of the third metal layer 7 asα3, the coefficients of thermal expansion are so set to satisfyα1<α2<α3 when the difference betweenα1 andα3 is≥10 ppm/°C. Further, the thickness of the second metal layer 5 is≥20% of the thickness of the first metal layer 3. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
