Thermal treatment apparatus utilizing heated lid

Abstract

A heater body or a circulation path for a heating gas is provided in an inner surface of a lid body that opens and closes an opening portion of a process tube. The circulation path is formed in such a manner that it passes through a gap between the lid body and the shaft of a rotation mechanism that rotates a quartz boat holding semiconductor wafers within the process tube. A heating gas at a temperature at least as high as the vaporization temperature of reaction products is made to circulate through this circulation path. Since the inner surfaces of the lid body are heated, reaction products do not adhere to the inner walls of the lid body and the lower portions of the process tube. Since there no source of contamination is generated thereby, the semiconductor wafers and the clean room are not contaminated. Since the circulation gas is made to flow in the reverse direction in the gap, there is no leakage of reaction gas therefrom. Thus the clean room is not contaminated and semiconductor wafers can be fabricated with a good yield.

Dependencies are inferred from the claim text.