Patent ID: 8498525

Claim:
A heat treatment method for heating a substrate by light irradiation of the substrate, the method comprising: a temperature-raising step of raising a surface temperature of said substrate to a predetermined processing temperature by light irradiation of said substrate from a flash lamp, producing an output waveform that reaches a peak at a first emission output; and a temperature-maintaining step of maintaining the surface temperature of said substrate at said processing temperature for 5 milliseconds or more by performing supplemental light irradiation of the substrate from the flash lamp after said peak, producing an emission output smaller than said first emission output, wherein a total of a light irradiation time in said temperature-raising step and a light irradiation time in said temperature-maintaining step is one second or less, and the light irradiation in the temperature-raising step and in the temperature-maintaining step is executed by applying a pulse signal to a gate of an insulated-gate bipolar transistor (IGBT) connected to the flash lamp to chopper control light emission from the flash lamp.