Patent ID: 8198544

Claim:
A printed wiring board, comprising: a plurality of interlayer resin insulation layers comprising a first interlayer resin insulation layer and a second interlayer resin insulation layer; and a plurality of conductive circuits formed on the first interlayer resin insulation layer and encapsulated by the first and second interlayer resin insulation layers such that spaces between the conductive circuits are filled with a resin material of the second interlayer resin insulation layer and covered with the resin material of the second interlayer resin insulation layer, wherein the conductive circuits include a first conductive circuit and a second conductive circuit positioned adjacent to the first conductive circuit, each of the first and second conductive circuits has a trapezoidal cross section, and the first and the second conductive circuits satisfy a formula, 0.10T≦|W 1 −W 2 |≦0.73T, and the first conductive circuit and the second conductive circuit have W 2 of 15 μm or less, where W 1 represents a width of a space between upper surfaces of the first and second conductive circuits, W 2 represents a width of a space between lower surfaces of the first and second conductive circuits, and T represents a thickness of each of the first and second conductive circuit.