| 摘要 |
PURPOSE:To arbitrarily change the variation of heat conductivity and insulation resistance in the thickness wise direction of a substrate, to obtain a circuit board which has desired heat conductive characteristic and insulation resistance characteristics and to prevent the peeling between layers caused by heat shock by varying the ratio of a metal component and an insulating magnetic component in the thickness wire direction of the board. CONSTITUTION:A circuit board 11 is constituted of a mixed material of a metal and an insulating ceramic composition, and the ratio of the metal component (shown by a broken line A) and the ratio of the ceramic composition (shown by a solid line B) are continuously varied ion the thickness wire direction. The board 11 allows the resistivity to be lower as it reaches a bottom surface 11b from a top surface 11a and a heat conductivity is continuously increased. Thus, thermal expansion coefficient is continuously changed in the thickness wire direction of the board, and layer peeling in the board caused by thermal expansion coefficient difference is suppressed. |
