One aspect of the invention relates to a method for producing a circuit carrier. For this purpose, an electrically insulating carrier is provided, having an upper side and also an underside opposite from the upper side. A first metal foil and a hardening material are likewise provided. Then, an upper metallization layer, which is arranged on the upper side and has a hardening area, is produced. In this case, at least one contiguous portion of the hardening area is created by at least part of the hardening material being diffused into the first metal foil.