Substrate processing apparatus, method of manufacturing semiconductor device and non-transitory computer-readable recording medium

A substrate processing apparatus comprising:

• a process chamber configured to accommodate a substrate;
• a first reactive gas supply line connected to the process chamber at a first location of the process chamber and configured to supply a reactive gas onto the substrate accommodated in the process chamber;
• a first valve configured to open and close the first reactive gas supply line;
• a second reactive gas supply line having one end connected to the first reactive gas supply line at an upstream side of the first valve and other end connected to the process chamber at a second location of the process chamber different from the first location of the process chamber to supply the reactive gas onto the substrate accommodated in the process chamber;
• a gas storage unit installed in line with the second reactive gas supply line;
• a second valve installed between the first reactive gas supply line and the gas storage unit, and configured to open and close the second reactive gas supply line;
• a third valve installed between the gas storage unit and the process chamber and configured to open and close the second reactive gas supply line;
• and
• a control unit configured to open the second valve with the first valve and the third valve closed such that the reactive gas is stored in the gas storage unit, and open the first valve and the third valve when the reactive gas is supplied onto the substrate accommodated in the process chamber such that the reactive gas is supplied onto the substrate via the first reactive gas supply line and the second reactive gas supply line simultaneously.