The yield of a manufacturing process of a semiconductor device is increased. The mass productivity of the semiconductor device is increased. The semiconductor device is manufactured by performing a step of performing plasma treatment on a first surface of a substrate; a step of forming a first layer over the first surface with the use of a material containing a resin or a resin precursor; a step of forming a resin layer by performing heat treatment on the first layer; and a step of separating the substrate and the resin layer from each other. In the plasma treatment, the first surface is exposed to an atmosphere containing one or more of hydrogen, oxygen, and water vapor.