Manufacturing method of soi semiconductor device

Abstract

To prevent, in the case of irradiating a single crystal semiconductor layer with a laser beam, an impurity element from being taken into the single crystal semiconductor layer at the time of laser irradiation. In a manufacturing method of an SOI substrate, a single crystal semiconductor substrate and a base substrate are prepared; an embrittlement region is formed in a region at a predetermined depth from a surface of the single crystal semiconductor substrate by irradiating the single crystal semiconductor substrate with accelerated ions; the single crystal semiconductor substrate and a base substrate are bonded to each other with an insulating layer interposed therebetween; a single crystal semiconductor layer is formed over the base substrate with the insulating layer interposed therebetween by heating the single crystal semiconductor substrate to cause separation using the embrittlement region as a boundary; an oxide film formed on the single crystal semiconductor layer is removed; and at least a surface of the single crystal semiconductor layer is melted by irradiating the surface of the single crystal semiconductor layer with a laser beam after the removal of the oxide film. The number of times the single crystal semiconductor layer is melted by the irradiation with the laser beam is one.