Patent ID: 8658951

Claim:
A heat treatment apparatus for performing a heat treatment on a plurality of substrates by supplying a gas into a depressurizable processing chamber having a sidewall made of aluminum or an aluminum alloy, the heat treatment apparatus comprising: a plurality of susceptors having conductive members for mounting the substrates thereon, each of the susceptors having an induction heating body divided into a central portion and a peripheral portion; a susceptor supporting unit for supporting the susceptors, which are spaced apart from each other at a regular interval in a row; an induction coil which is arranged inside the processing chamber to surround a circumference of each of the susceptors, a temperature of the induction coil being controllable, and wherein, for the induction heating body of each of the plurality of susceptors, the central portion of the induction heating body is farther away from the induction coil than the peripheral portion of the induction heating body is from the induction coil; a high frequency current circuit for applying two high frequency currents of different frequencies to the induction coil; a control unit configured to perform temperature control by changing a ratio between a heat value at the central portion of the induction heating body and a heat value at the peripheral portion thereof by controlling the two high frequency currents of different frequencies to be applied at the same time as a superposition of the two high frequency current, and a wall temperature control mechanism for controlling a temperature of the sidewall independently of temperature of the plurality of susceptors.