Patent ID: 8034183

Claim:
A cleaning method comprising: purging the process chamber by introducing a purge gas into the process chamber while suctioning the process chamber, wherein the process chamber is a process chamber of a substrate processing apparatus which is configured to perform an oxidizing process, a nitriding process or an oxynitriding process to a substrate; heating an interior of the process chamber; and cleaning the process chamber by introducing a cleaning gas comprising O 2 gas and H 2 gas into the process chamber and by generating a plasma of the cleaning gas, thereby removing contaminants comprising alkali metals or alkali earth metals present in the process chamber by active species contained in the plasma, wherein, when removing the contaminants, temperature of the interior of the process chamber is set within a range of from room temperature to 800° C. and the pressure in the process chamber is set within a range of 266.7 to 6665 Pa, wherein the purging is performed while the introducing of the O 2 gas and H 2 gas into the process chamber is stopped and the generating of the plasma is stopped, wherein said cleaning method is performed during a time period before the substrate processing apparatus performs the oxidizing process, a nitriding process or an oxynitriding process to any substrate after the substrate processing apparatus is subjected to setting-up or maintenance, wherein an operation set comprising the purging and the cleaning subsequent to the purging is performed for plural times during the time period, wherein said cleaning method removes the alkali metals or the alkali earth metals which are adhered to surfaces in the process chamber when the setting-up or the maintenance is being performed.