Method of cleaning reaction tube, method of manufacturing semiconductor device, and substrate processing apparatus

A method of manufacturing a semiconductor device, comprising:

• a cleaning step of cleaning a reaction tube, the cleaning step including:
• a first annealing step of annealing the reaction tube;
• a first cleaning step of cleaning an inner surface of the reaction tube, after the first annealing step, with a liquid including a fluorine compound having a first concentration;
• a first rinsing step of washing away the fluorine compound used in the first cleaning step with pure water, wherein performing the first rinsing step one or more times is set to be a first cycle, and the first cycle is performed one or more times;
• a second annealing step of annealing the reaction tube;
• a second cleaning step of cleaning the inner surface of the reaction tube, after the second annealing step, with a liquid including a fluorine compound having a second concentration higher than the first concentration;
• and
• a second rinsing step of washing away the fluorine compound used in the second cleaning step with pure water, the second rinsing step being performed two or more times;
• and
• a substrate-processing step of accommodating one or more substrates in a process chamber installed inside the reaction tube after the cleaning step and processing the substrates.