Substrate processing apparatus, substrate retainer and method of manufacturing semiconductor device

A substrate retainer comprising

• a plurality of support columns configured to support a substrate,
• wherein at least one among the plurality of the support columns comprises:
• a hollow portion through which an inert gas is supplied;
• and
• a gas supply port through which the inert gas is supplied toward an inner wall of a reaction tube.

A method of manufacturing a semiconductor device, comprising:

• (a) loading a substrate retainer in which a substrate is supported into a reaction tube;
• (b) supplying a process gas into the reaction tube;
• (c) unloading the substrate retainer out of the reaction tube;
• and
• (d) supplying an inert gas toward an inner wall of the reaction tube through a support column of the substrate retainer.