Patent ID: 8835813

Claim:
A heat treatment apparatus for heating a substrate by irradiating the substrate with light, comprising: a holder that holds a substrate; a light-irradiation unit that irradiates the substrate held by said holder with light; and a light-emission control unit that controls a light-emission output of said light-irradiation unit, said light-emission control unit comprising a switching element connected in series with said light-irradiation unit, a coil and a capacitor, and a pulse generator for applying a pulse signal to a gate of said switching element, wherein said pulse generator is configured to apply a pulse signal to said switching element so that a total light-irradiation time is not more than one second and that said light-irradiation unit performs a first light-irradiation of the substrate with a first light-emission output being as a target value, then performs a second light-irradiation of the substrate in accordance with an output waveform that peaks at a second light-emission output that is higher than said first light-emission output and a maximum value of the light-emission output of said first light-irradiation, and further performs an additional third light-irradiation of the substrate, after said peak, with a light-emission output that is lower than said second light-emission output.