A plurality of rectangular single crystal semiconductor substrates are prepared. Each of the single crystal semiconductor substrates is doped with hydrogen ions and a damaged region is formed at a desired depth, and a bonding layer is formed on a surface thereof. The plurality of single crystal substrates with the damaged regions formed therein and the bonding layers formed thereover are arranged on a tray. Depression portions for holding the single crystal semiconductor substrates are formed in the tray. With the single crystal semiconductor substrates arranged on the tray, the plurality of single crystal semiconductor substrates with the damaged regions formed therein and the bonding layers formed thereover are bonded to a base substrate. By performing heat treatment and dividing the single crystal semiconductor substrates along the damaged regions, the plurality of single crystal semiconductor layers that are sliced are formed over the base substrate.