Surface-treated copper foil, and copper-clad laminate and printed wiring board using same

Provided is a surface-treated copper foil in which the treated surface has a three-dimensional shape comprising a plurality of contiguous fine copper particles, the surface area ratio per 1 m2 of the two-dimensional area is high, and the anchoring effect is excellent, so that the surface-treated copper foil exhibits high adhesion to a low-dielectric resin base material, and the surface-treated copper foil has excellent adhesion to a low-dielectric resin base material even when exposed to high temperatures for a long period of time. Provided is a printed wiring board for high-frequency signal transmission, which has excellent transmission characteristics equivalent to that of a non-roughened copper foil, and which can be used as a printed wiring board for high-frequency signal transmission, said printed wiring board being also capable of producing a multilayer printed wiring board having excellent interlayer adhesion. The surface-treated copper foil according to the present invention comprises, on at least one