Gas cluster irradiation mechanism, substrate processing apparatus using same, and gas cluster irradiation method

A substrate processing apparatus for performing predetermined processing on a substrate to be processed by using a gas cluster, comprising:

• a processing chamber maintained in a vacuum state;
• a substrate supporting unit configured to support the substrate to be processed in the processing chamber;
• and
• a gas cluster irradiation mechanism for generating the gas cluster by adiabatic expansion a gas into the processing chamber and irradiating the gas cluster onto the substrate to be processed,
• wherein the gas cluster irradiation mechanism includes:
• at least one nozzle unit having a plurality of gas injection nozzles configured to inject the gas into the processing chamber which is maintained in a vacuum state;
• and
• a gas supply unit configured to supply the gas to the nozzle unit,
• wherein the number of the nozzle unit is set such that when the gas is supplied from the gas injection nozzles at a preset flow rate a pressure in the processing chamber remains below a limit at which the gas cluster begins to be destroyed, and
• wherein the gas injection nozzles are arranged with a preset interval between neighboring gas injection nozzles such that respective areas in which residual gas from the neighboring gas injection nozzles spreads do not overlap with each other, the residual gas being part of the gas injected from the gas injection nozzles and not contributing to generation of the gas cluster.