Patent ID: 8343847

Claim:
A manufacturing method of an SOI semiconductor device, comprising the steps of: a first step of forming an embrittlement region in a single crystal semiconductor substrate by irradiating the single crystal semiconductor substrate with accelerated ions; a second step of bonding the single crystal semiconductor substrate and a base substrate to each other with an insulating layer interposed therebetween; a third step of forming a single crystal semiconductor layer 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; a fourth step of removing an oxide film formed on a surface of the single crystal semiconductor layer; a fifth step of melting a portion of the surface of the single crystal semiconductor layer by irradiating the portion of the surface of the single crystal semiconductor layer with a laser beam in a chamber with a reduced-pressure atmosphere; and a sixth step of forming an insulating film over the single crystal semiconductor layer, wherein the fourth step is followed by the fifth step, and the fifth step is followed by the sixth step, wherein the number of times that the portion of the surface of the single crystal semiconductor layer is melted from the fourth step to the sixth step is one, and wherein the repetition rate of the laser beam is 10 MHz or higher.