摘要 |
An SOI substrate having a single crystal semiconductor layer the surface of which has high planarity is manufactured. A semiconductor substrate is doped with hydrogen to form a damaged region containing a large amount of hydrogen. After a single crystal semiconductor substrate and a supporting substrate are bonded to each other, the semiconductor substrate is heated to separate the single crystal semiconductor substrate in the damaged region. While a heated high-purity nitrogen gas is sprayed on a separation surface of a single crystal semiconductor layer which is separated from the single crystal semiconductor substrate and irradiation with a microwave is performed from the back side of the supporting substrate, the separation surface is irradiated with a laser beam. The single crystal semiconductor layer is melted by irradiation with the laser beam, so that the surface of the single crystal semiconductor layer is planarized and re-single-crystallization thereof is performed. In addition, the length of the melting time is increased by irradiation with the nitrogen gas and the microwave; thus, the re-single-crystallization is performed more efficiently.
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