Cleaning method and plasma processing method

1. 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.

2. The cleaning method according to claim 1 , wherein a flow rate ratio of the H 2 gas and the O 2 gas contained in the cleaning gas is in a range of about 0.5:1 to 20:1.

3. The cleaning method according to claim 1 , wherein the contaminants are Na, K, Mg or Ca present in the process chamber.

4. The cleaning method according to claim 1 , wherein the cleaning is performed by using a plasma formed by introducing microwaves into the process chamber by using a planer antenna having a plurality of slots.

5. A plasma processing apparatus configured to perform an oxidizing process, a nitriding process or oxynitriding process, comprising:

a plasma supply source that generates plasma;

a process vessel defining a process chamber for performing a process for a substrate by using the plasma;

a substrate support table that supports thereon the substrate in the process vessel;

an exhaust device for decompressing an interior of the process vessel;

a gas supply system for supplying a cleaning gas comprising O 2 gas and H 2 gas, and a purge gas into the process vessel;

a heater configured to heat an interior of the processing chamber; and

a control unit configured to control operation of said plasma processing apparatus during a time period before the substrate processing apparatus performs the oxidizing process, the nitriding process or the oxynitriding to any substrate after said substrate processing apparatus is subjected to setting-up or maintenance,

to perform a cleaning method comprising

purging the process chamber by introducing a purge gas into the process chamber while suctioning the process chamber;

heating an interior of the process chamber; and

cleaning the process chamber by introducing a cleaning gas comprising O 2 gas and H 2 as into the process chamber and 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 the temperature of the interior of the process chamber is set within a range 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

wherein an operation set comprising the purging and the cleaning subsequent to the purging is performed for plural times during the time period.

6. The method according to claim 1 , wherein each of the cleaning is performed for 100 to 300 seconds, and each of the purging is performed for 5 to 150 seconds.

7. The method according to claim 1 , wherein pressure in the process chamber during the purging is the same as that during the cleaning.