Printed wiring board

摘要

A printed wiring board includes a core substrate including an insulative substrate, a first conductive layer formed on first surface of the insulative substrate, and a second conductive layer formed on second surface of the insulative substrate, a first buildup laminated on first surface of the core and including an interlayer insulation layer, a conductive layer formed on the insulation layer, and a via conductor penetrating through the insulation layer and connected to the conductive layer, and a second buildup laminated on second surface of the core and including an interlayer insulation layer, a conductive layer formed on the interlayer insulation layer, and a via conductor penetrating through the insulation layer and connected to the conductive layer. The insulation layer of the first buildup has thermal expansion coefficient set higher than thermal expansion coefficient of the insulation layer of the second buildup.

主权项

1. A printed wiring board, comprising:
a core substrate comprising an insulative substrate, a first conductive layer formed on a first surface of the insulative substrate, and a second conductive layer formed on a second surface of the insulative substrate; a first buildup layer laminated on a first surface of the core substrate and comprising an interlayer resin insulation layer, a conductive layer formed on the interlayer resin insulation layer of the first buildup layer, and a via conductor penetrating through the interlayer resin insulation layer of the first buildup layer and connected to the conductive layer of the first buildup layer; and a second buildup layer laminated on a second surface of the core substrate and comprising an interlayer resin insulation layer, a conductive layer formed on the interlayer resin insulation layer of the second buildup layer, and a via conductor penetrating through the interlayer resin insulation layer of the second buildup layer and connected to the conductive layer of the second buildup layer, wherein the interlayer resin insulation layer of the first buildup layer has a thermal expansion coefficient which is set higher than a thermal expansion coefficient of the interlayer resin insulation layer of the second buildup layer, and the thermal expansion coefficients of the interlayer resin insulation layers of the first and second buildup layers are set such that the thermal expansion coefficient of the interlayer resin insulation layer of the first buildup layer divided by the thermal expansion coefficient of the interlayer resin insulation layer of the second buildup layer is a value of greater than 1 but 1.5 or smaller, where the thermal expansion coefficients of the interlayer resin insulation layers of the first and second buildup layers are values in X-Y directions obtained in a temperature range of 195 degrees to 280 degrees.