A thermal treatment apparatus and method for processing a wafer are provided. The thermal treatment apparatus includes a process chamber for thermally treating the wafer, a heating unit for heating the wafer in the process chamber, and a gas supply unit for supplying a gas and controlling a gas pressure differently by sections of the wafer. The heating unit is provided in at least one of the upper side and the lower side of the process chamber. The heating unit includes a plurality of heater blocks capable of controlling a temperature for sections of the wafer.