Printed wiring board

A printed wiring board, comprising:

• a first buildup layer comprising a first interlayer resin insulating layer and a second interlayer resin insulating layer;
• and
• a second buildup layer formed on the first buildup layer and comprising an outermost interlayer resin insulating layer and an outermost conductive layer formed on the outermost interlayer resin insulating layer,
• wherein the first buildup layer includes a first signal line interposed between the first interlayer resin insulating layer and the second interlayer resin insulating layer, a first ground layer formed on a surface of the first interlayer resin insulating layer, and a second ground layer formed on a surface of the second interlayer resin insulating layer such that the first signal line is interposed between the first ground layer and the second ground layer, the first and second interlayer resin insulating layers in the first buildup layer and the outermost interlayer resin insulating layer in the second buildup layer comprise resin materials, respectively, such that each of the first and second interlayer resin insulating layers in the first buildup layer comprises a single material, and the first and second interlayer resin insulating layers in the first buildup layer are different in material, thickness or a combination thereof from the outermost interlayer resin insulating layer in the second buildup layer.