Even when a substrate for treatment is joined with a supporting substrate having an outer shape larger than that of the substrate for treatment, with a photothermal conversion layer and an adhesive layer interposed, and the surface of the substrate for treatment on the side opposite this joined surface is treated, the occurrence of a defective external appearance on the treatment surface of the substrate for treatment is prevented.An adhesive layer 4 is formed on one surface of a substrate for treatment 3, a photothermal conversion layer 2 is formed on one surface of a supporting substrate 1 having a surface with an outer shape larger than that of the surface of the substrate for treatment, and the substrate for treatment 3 is bonded onto the surface of the photothermal conversion layer 2 with the adhesive layer 4 interposed, to obtain a layered member. This layered member is placed on a spin chuck 9 in a chamber 8 of a spin coater device, an alkaline aqueous solution 11 is dropped onto a portion 2a of the photothermal conversion layer 2 which protrudes from the substrate for treatment, and thereafter cleaning is performed on this portion using a high-pressure cleaning nozzle 12. Then, grinding, wet treatment, or similar treatment is performed on the surface of the substrate for treatment 3, to manufacture a semiconductor device.