Substrate processing apparatus

A substrate processing apparatus which supplies a process gas to a substrate placed in a hermetic process chamber to perform substrate processing, comprising:

• a first hole portion formed through an inner circumferential surface of a sidewall of the process chamber and horizontally extending outward, the first hole portion having a circular cross-section;
• a second hole portion formed to be contiguous with an outer end of the first hole portion and defining a supply channel for the process gas, the second hole portion being concentric with the first hole portion and having a smaller diameter than the first hole portion and a circular cross-section;
• a gas nozzle, a proximal end of which is inserted into the first hole portion through an inner end of the first hole portion, the gas nozzle being configured to supply the process gas from the second hole portion to the substrate;
• a plurality of seal members spaced apart from each other in a longitudinal direction of the gas nozzle between an outer circumferential surface of the gas nozzle and the first hole portion, each of the seal members being formed in an annular shape in a circumferential direction of the gas nozzle;
• and
• an annular spacer inserted into the outer end of the first hole portion and pressed against an annular surface of an opening periphery of the second hole portion by the gas nozzle in a state where the proximal end of the gas nozzle is engaged with the annular spacer.