Provided is a semiconductor device manufacturing method in which semiconductor elements are formed into multiple layers through the lamination of wafers in which the semiconductor elements are fabricated, the method being suited for efficiently creating multiple layers of thin wafers while suppressing warping of a wafer laminate. The method of the present invention includes a preparation step, a thinning step, a bonding step, a removal step, and a multilayering step. In the preparation step, a reinforced wafer is prepared, the reinforced wafer having a laminated structure that includes: a wafer including an element forming surface and a back surface opposite from the element forming surface; a supporting substrate; and a temporary adhesive layer for forming temporary adhesion, the temporary adhesive layer being provided between the element forming surface side of the wafer and the supporting substrate.