US Patent 7804031 Printed wiring board and manufacturing method thereof

A printed wiring board having an interlayer insulation layer and conductive circuits formed on the interlayer insulation layer. The conductive circuits include a first conductive circuit and a second conductive circuit positioned adjacent to each other, and the first and second conductive circuits satisfy a formula, 0.10 T≦|W1−W2|≦0.73 T, where W1 represents an upper conductive circuit space between the first and second conductive circuits, W2 represents a lower conductive circuit space between the first and second conductive circuits, and T represents a thickness of the first and second conductive circuits.