A production method includes: preparing a metal clad laminate including a dielectric layer≤30 μm thick, a first metal foil on a first surface of the dielectric layer, a second metal foil on a second surface of the dielectric layer, first and second carriers on the metal foil via a releasable layer; arranging the pair of metal clad laminates on a resin substrate so the first carrier of each metal clad laminate faces the resin substrate on each surface of the resin substrate; releasing the second carrier from a laminated member to expose the second metal foil; forming a pattern on the second metal foil; arranging an insulating layer on the pattern and arranging a metal layer on the insulating layer; and separating the first carrier and the first metal foil from each other. The dielectric layer has a strain energy at break of 1.8 MJ or less.