Metal foil, carrier with metal layer comprising the same and printed circuit board comprising the same

The present invention relates to a metal layer having a rough surface, a carrier-attached metal foil including the metal layer, and a printed circuit board manufactured using the metal layer. The metal layer includes a plurality of flat-topped projections and has a thickness of 1 [mu]m or less. Each of the projections includes a protrusion having a truncated cone or polygonal truncated pyramidal shape and a plateau formed at the upper end of the protrusion. The projections are formed by electroless plating. The protrusion has a plurality of microprojections formed on the lateral surface thereof other than the plateau to enhance the adhesion to an insulating resin substrate due to its increased surface area.