Patent ID: 8835811

Claim:
A thermal processing apparatus comprising: a furnace body; a processing vessel disposed in the furnace body, the processing vessel defining a space between the furnace body and the processing vessel, the space including therein a plurality of unit areas, wherein the processing vessel is configured to accommodate a plurality of objects to be processed therein; a plurality of heating units disposed on an inner surface of the furnace body, corresponding to each of the unit areas of the space; a plurality of in-furnace temperature sensors disposed within the furnace and corresponding to each of the unit areas of the space; and a control unit configured to control the heating units of the unit areas, based on a signal from the in-furnace temperature sensors of each of the unit areas; wherein the control unit includes a first control zone mode in which a number of control zones, which are formed of the unit areas and are independently controlled, corresponds to a total number of the unit areas, and a second control zone mode in which a number of control zones, which are formed of the unit areas and are independently controlled, is less than the total number of the unit areas; and wherein the control unit is configured to select the second control zone mode to control the heating units of the respective control zones when a temperature is increased or decreased, and is configured to select the first control zone mode to control the heating units of the respective control zones when a temperature is stabilized.