Abstract: There is provided a method for manufacturing a wiring substrate in which damage to a device layer during carrier release can be suppressed, and a photolithography process can be carried out with good accuracy on the device layer after carrier release. This method includes: providing a laminated sheet including a carrier, a release layer, a metal layer, and a device layer in order; making a cut line from a surface of the laminated sheet on the carrier side so that the cut line passes through the carrier, the release layer, and the metal layer when the laminated sheet is seen in a cross-sectional view; and removing outer edge portions outside the cut line in the carrier, the release layer, and the metal layer, thereby exposing part of a surface of the device layer on the metal layer side to form a pressurizable exposed portion for promoting release of the carrier.

Abstract: Provided is a carrier-attached metal foil which can suppress the number of foreign matter particles on the surface of a metal layer to enhance circuit formability, and can keep stable releasability even after heating at a high temperature of 240° C. or higher (for example, 260° C.) for a long period of time. The carrier-attached metal foil includes a carrier, a release functional layer provided on the carrier, the release functional layer including a metal oxynitride, and a metal layer provided on the release functional layer.