Abstract: An electronic component mounting base includes a base, a first, second and third conductor layers, and first and second via conductors. The base includes first and second insulating layers. The first insulating layer has a first surface and a second surface opposite to the first surface. The second insulating layer has a third surface facing overlapping the second surface, and a fourth surface opposite the third surface. The first conductor layer includes a first electrode portion positioned on the first surface. The second conductor layer is positioned between the second and third surfaces. The third conductor layer includes a second electrode portion positioned on the fourth surface. The first via conductor extends penetrating from the first to the second surfaces, and connects the first conductor and second conductor layers. The second via conductor extends penetrating from the third to the fourth surfaces, and connects the second and third conductor layers.

Abstract: An electronic component mounting substrate according to an embodiment of the present disclosure includes a substrate and a plurality of via conductors. The substrate includes a mounting region where an electronic component is to be mounted, and one or more insulating layers. The plurality of via conductors extend through the one or more insulating layers in a thickness direction of the substrate. The plurality of via conductors are arranged, in a plan view of the one or more insulating layers, in m columns in an X direction and n rows in a Y direction, where m and n are natural numbers, and positioned either in odd-numbered rows of odd-numbered columns and even-numbered rows of even-numbered columns only, or in even-numbered rows of odd-numbered columns and odd-numbered rows of even-numbered columns only.

Abstract: A circuit board includes a metal circuit plate, a metallic heat diffusing plate disposed below the metal circuit plate and having an upper surface and a lower surface, a metallic heat dissipating plate below the heat diffusing plate, an insulating substrate disposed between the metal circuit plate and the heat diffusing plate, and an insulating substrate disposed between the heat diffusing plate and the heat dissipating plate. A grain diameter of metal grains contained in the heat diffusing plate decreases from each of the upper surface and the lower surface of the heat diffusing plate toward a center portion of the heat diffusing plate in a thickness direction.

Abstract: A circuit board includes an insulating substrate; a metal circuit sheet joined to a first principal surface of the insulating substrate; and a heat dissipating sheet made of metal and joined to a second principal surface of the insulating substrate, the second principal surface being opposite the first principal surface. The thickness of the heat dissipating sheet is at least 3.75 times the thickness of the metal circuit sheet. The size of metal grains contained in the heat dissipating sheet is smaller than the size of metal grains contained in the metal circuit sheet, and decreases with increasing distance from the second principal surface of the insulating substrate.

Abstract: A circuit board includes a metal circuit plate, a metallic heat diffusing plate disposed below the metal circuit plate and having an upper surface and a lower surface, a metallic heat dissipating plate below the heat diffusing plate, an insulating substrate disposed between the metal circuit plate and the heat diffusing plate, and an insulating substrate disposed between the heat diffusing plate and the heat dissipating plate. A grain diameter of metal grains contained in the heat diffusing plate decreases from each of the upper surface and the lower surface of the heat diffusing plate toward a center portion of the heat diffusing plate in a thickness direction.

Abstract: A circuit board includes an insulating substrate; a metal circuit sheet joined to a first principal surface of the insulating substrate; and a heat dissipating sheet made of metal and joined to a second principal surface of the insulating substrate, the second principal surface being opposite the first principal surface. The thickness of the heat dissipating sheet is at least 3.75 times the thickness of the metal circuit sheet. The size of metal grains contained in the heat dissipating sheet is smaller than the size of metal grains contained in the metal circuit sheet, and decreases with increasing distance from the second principal surface of the insulating substrate.