Substrate processing apparatus, method of manufacturing semiconductor device, and non-transitory computer-readable recording medium

1. A method of manufacturing a semiconductor device by processing a substrate by supplying a processing space with a processing gas dispersed in a buffer space disposed at an upstream side of the processing space, the method comprising:

(a) transferring the substrate into the processing space while exhausting a transfer space of the substrate by a first vacuum pump;

(b) closing a first valve disposed at a downstream side of the first vacuum pump;

(c) supplying the processing gas into the processing space via the buffer space while exhausting the processing gas from the processing space through a third valve connected to the processing space;

(d) exhausting an inner atmosphere of the processing space through the third valve by supplying a purge gas into the processing space via the buffer space with a second valve connected to the buffer space closed and a supply of the process gas into the processing space suspended; and

(e) exhausting the buffer space through the second valve and an exhaust pipe connected to a downstream side of the first valve after performing (d) by supplying the purge gas into the buffer space with the third valve closed and the second valve open.

2. The method of claim 1 , wherein (c) comprises (c-1) supplying a first processing gas and (c-2) supplying a second processing gas, and (d) and (e) are performed between (c-1) and (c-2).

3. The method of claim 1 , wherein (b) is performed after closing a fourth valve disposed at an upstream side of the first vacuum pump after (a) is performed.

4. The method of claim 1 , wherein (c) is performed while suspending the exhausting of the transfer space.

5. The method of claim 1 , further comprising: exhausting the inner atmosphere of the processing space through the third valve after performing (e) by supplying the purge gas into the processing space with the second valve closed.