Patent ID: 7651783

Claim:
In a copper-clad laminate used for higher frequency applications and comprising a surface treated copper foil having at least one side in which surface roughening treatment has not been applied and which is laminated to a substrate, the improvement comprising the surface-treated copper foil is formed from a copper foil having at least one side in which surface roughening treatment has not been applied and which is sequentially provided on said at least one side with a heat-resistant layer, an anticorrosive layer and an olefin-based silane coupling agent layer on the at least one side thereof, the heat-resistant layer is at least one film selected from the group consisting of a zinc-tin film, a zinc-nickel film, a zinc-cobalt film, a copper-zinc film and a copper-nickel-cobalt film, the anticorrosive layer is a film formed by a zinc chromate or a chromate treatment, a siloxane coating is formed over the anticorrosive layer, the olefin-based silane coupling agent is provided over the siloxane coating, and the substrate is bonded to the olefin-based silane coupling agent layer and contains an insulating resin having a curing system involving double bonds and selected from the group consisting of thermosetting polyphenylene ether resins, thermosetting polyphenylene ether resins containing a polystyrene polymer, resin compositions containing a triallyl cyanurate polymer or copolymer, acrylic or methacrylic modified epoxy resin compositions, phenol-added butadiene polymers, diallyl phthalate resins, divinylbenzene resins, polyfunctional methacryloyl resins, polybutadiene resins, styrene-butadiene resins and styrene-butadiene-styrene-butadiene resins, wherein the copper foil's at least one side has a surface roughness Rz of no more than 3.5 μm and the insulating resin is cured after the surface-treated copper foil is laminated on the insulating resin.