If the size of a single crystal silicon layer attached is not appropriate, even when a large glass substrate is used, the number of panels to be obtained cannot be maximized. Therefore, in the present invention, a substantially quadrangular single crystal semiconductor substrate is formed from a substantially circular single crystal semiconductor wafer, and a damaged layer is formed by irradiation with an ion beam into the single crystal semiconductor substrate. A plurality of the single crystal semiconductor substrates are arranged so as to be separated from each other over one surface of a supporting substrate. By thermal treatment, a crack is generated in the damaged layer and the single crystal semiconductor substrate is separated while a single semiconductor layer is left over the supporting substrate. After that, one or a plurality of display panels is manufactured from the single crystal semiconductor layer bonded to the supporting substrate.