Abstract: A heat treatment apparatus includes a processing chamber having a gate valve at a sidewall and a cover at a ceiling via a sealing member; a gate valve heating unit provided at the gate valve; a processing chamber heating unit provided at a sidewall of the processing chamber; and a temperature controller that controls a set temperature for the sidewall of the processing chamber adjacent to the gate valve to be lower than a set temperature for an opposite sidewall of the processing chamber from the gate valve by controlling the processing chamber heating unit. The two set temperatures are set to be higher than a sublimation temperature of a reaction by-product, or higher than a condensation temperature of the gas, and the two set temperatures are also set to be lower than a temperature at which an amount of a gas permeating the sealing member increases.

Abstract: Disclosed is a susceptor which achieves uniform temperature distribution of a wafer placed on the susceptor, and also disclosed is a substrate processing apparatus provided with the susceptor. An annular recess 12a is formed in an intermediate portion between the central portion and the peripheral portion of a wafer support surface of the susceptor 12. Due to the provision of the recess, the substrate heating effect by thermal radiation from the susceptor is suppressed in the intermediate portion. The geometrical dimension of the recess is determined taking the chamber internal pressure into consideration.