Patent ID: 8945329
Filing Date: 2015-02-03
Classification: H05K,Y10T

Abstract:
1. A method for manufacturing a printed wiring board, comprising: laminating a first core substrate having a through-hole conductor formed through the first core substrate and a second core substrate having a through-hole conductor formed through the second core substrate; forming a first upper buildup layer on a surface of the first core substrate; forming a second upper buildup layer on a surface of the second core substrate; separating the first core substrate and the second core substrate from each other; laminating the first upper buildup layer formed on the first core substrate and the second upper buildup layer formed on the second core substrate; forming a first lower buildup layer on an opposite surface of the first core substrate; forming a second lower buildup layer on an opposite surface of the second core substrate; and separating the first upper buildup layer and the second upper buildup layer, wherein the forming of the first upper buildup layer comprises forming a plurality of resin insulation layers, the forming of the second upper buildup layer comprises forming a plurality of resin insulation layers, the forming of the first lower buildup layer comprises forming at least one resin insulation layer, the forming of the second lower buildup layer comprises forming at least one resin insulation layer, the plurality of insulation layers in the first upper buildup layer has a greater number of layers than the at least one resin insulation layer in the first lower buildup layer, the plurality of insulation layers in the second upper buildup layer has a greater number of layers than the at least one resin insulation layer in the second lower buildup layer, the first upper buildup layer has an outermost resin insulation layer comprising a material different from a material of an outermost resin insulation layer of the first lower buildup layer, the second upper buildup layer has an outermost resin insulation layer comprising a material different from a material of an outermost resin insulation layer of the second lower buildup layer, the outermost resin insulation layer of the first upper buildup layer has a thermal expansion coefficient which is lower than a thermal expansion coefficient of the first core substrate, the outermost resin insulation layer of the first lower buildup layer has a thermal expansion coefficient which is higher than a thermal expansion coefficient of the first core substrate, the outermost resin insulation layer of the second upper buildup layer has a thermal expansion coefficient which is lower than a thermal expansion coefficient of the second core substrate, the outermost resin insulation layer of the second lower buildup layer has a thermal expansion coefficient which is higher than a thermal expansion coefficient of the second core substrate, the outermost resin insulation layer of the first lower buildup layer does not have a reinforcing material, and the outermost resin insulation layer of the second lower buildup layer does not have a reinforcing material.