Patent ID: 8686320

Claim:
A heat treatment method irradiating a substrate with flashes of light from flash lamps to heat the substrate, comprising: (a) a first irradiation step of irradiating said substrate with a flash of light of a first pulse, said first irradiation step is started at a first time; and (b) a second irradiation step of irradiating said substrate with a flash of light of a second pulse, said second irradiation step is started at a second time later than said first time; wherein, at least a part of the irradiation of a flash of light of said second irradiation step is superimposed on the irradiation of a flash of light of said first irradiation step, and the surface temperature of said substrate is increased to a treatment temperature of a predetermined value by the irradiation of the flash of light of said first irradiation step, and the surface temperature of said substrate is maintained at said treatment temperature equal to said predetermined value for not less than a predetermined duration of time by the irradiation of the flash of light of said second irradiation step.