TWI587757B

The purpose of the present invention is to provide a copper foil that has better adhesiveness with an insulating resin substrate than an unroughened copper foil and has etchability as good as that of an unroughened copper foil. In order to achieve this purpose, used is a copper foil comprising a layer subjected to a roughening treatment on at least one surface of the copper foil, the copper foil being characterized in that the layer subjected to the roughening treatment comprises a composite copper compound and has a fine irregular structure formed from needle-shaped or plate-shaped convex sections with sizes of 500 nm or less, and in that a layer treated with a silane coupling agent is disposed on the surface of the layer subjected to the roughening treatment. Alternatively, used is a copper foil with a carrier foil comprising a carrier foil/joint interface layer/copper foil layer structure, the copper foil being characterized in that, on the surface of the copper foil layer, disposed is a layer subjected to