Cleaning method, method of manufacturing semiconductor device and substrate processing apparatus

1. A cleaning method comprising:

removing deposits adhered to an inside of a processing vessel by forming a film on a substrate in the processing vessel, and after that, supplying a cleaning gas into the processing vessel,

wherein the removing the deposits includes:

a first step of supplying the cleaning gas into the processing vessel at a first flow rate when a temperature of a connection portion connecting an exhaust pipe that exhausts the interior of the processing vessel and the processing vessel is lower than a first temperature; and

a second step of supplying the cleaning gas to the processing vessel while gradually decreasing the flow rate of the cleaning gas from the first flow rate to a second flow rate lower than the first flow rate when the temperature of the connection portion reaches a first temperature.

2. The cleaning method according to claim 1 , wherein the removing the deposits further includes a third step of supplying the cleaning gas into the processing vessel while macroscopically decreasing the flow rate of the cleaning gas at flow rates lower than the second flow rate so that a second temperature is maintained after the temperature of the connection portion reaches the second temperature higher than the first temperature.

3. The cleaning method according to claim 1 , wherein the flow rate of the cleaning gas decreases exponentially in the second step.

4. The cleaning method according to claim 2 , wherein the second temperature is set according to a tolerance temperature of the exhaust pipe to the cleaning gas.

5. The cleaning method according to claim 2 , wherein in the third step, the flow rate of the cleaning gas fluctuates during the macroscopic decrease so that a pressure in the processing vessel increases and decreases.

6. A method of manufacturing a semiconductor device, comprising:

forming a film on a substrate in a processing vessel; and

removing deposits adhered to an inside of the processing vessel by supplying a cleaning gas into the processing vessel,

wherein the removing the deposits includes:

a first step of supplying the cleaning gas into the processing vessel at a first flow rate when a temperature of a connection portion connecting an exhaust pipe that exhausts the interior of the processing vessel and the processing vessel is lower than a first temperature; and

a second step of supplying the cleaning gas to the processing vessel while gradually decreasing the flow rate of the cleaning gas from the first flow rate to a second flow rate lower than the first flow rate when the temperature of the connection portion reaches a first temperature.

7. A substrate processing apparatus, comprising:

a processing vessel accommodating a substrate in the processing vessel;

a film forming gas supply unit that supplies a film forming gas to the substrate in the processing vessel;

a cleaning gas supply unit that supplies a cleaning gas into the processing vessel;

a connection portion connecting an exhaust pipe that exhausts an interior of the processing vessel and the processing vessel; and

a controller that controls the film forming gas supply unit and the cleaning gas supply unit to perform forming a film by supplying the film forming gas to the substrate in the processing vessel and removing deposits adhered to the inside of the processing vessel by supplying the cleaning gas into the processing vessel, wherein, in the removing the deposits, when the temperature of the connection portion is lower than a first temperature, a first process of supplying the cleaning gas into the processing vessel at a first flow rate is performed, and when the temperature of the connection portion reaches the first temperature, a second process of supplying the cleaning gas to the interior of the processing vessel while gradually decreasing the flow rate of the cleaning gas from the first flow rate to a second flow rate lower than the first flow rate is performed.