Patent ID: 6996453

Claim:
A method of processing a substrate comprising: (a) providing purging gas into a substrate transfer chamber, and re-circulating the purging gas through the substrate transfer chamber; (b) loading a container, containing a plurality of substrates, onto a load port disposed outside of the substrate transfer chamber; (c) transferring the substrates from the container on the load port into the substrate transfer chamber using a robot disposed within the substrate transfer chamber; (d) transferring the substrates from the substrate transfer chamber to at least one substrate processing chamber; (e) processing the substrates within said at least one substrate process chamber; (f) transferring the processed substrates from said at least one process chamber into a container disposed on the load port at a standby position at which the interior of the container is exposed to the interior of the substrate transfer chamber, wherein said providing of the purging gas into the substrate transfer chamber, and said re-circulating of the purging gas through the substrate transfer chamber of step (a) are continuously carried out during the steps of (b) to (f) such that the container into which the substrates are being transferred in step (f) is filled with the purging gas from the substrate transfer chamber at the time a substrate is first transferred into the container, whereby the substrates in the container are enveloped by the purging gas; and (g) measuring the humidity in the substrate transfer chamber in real time during the step of (a), determining a value for the level of humidity in the transfer chamber at which condensate will not form on a wafer accommodated within a container at said standby position, increasing the amount of the purging gas being supplied into the substrate transfer chamber when the measured humidity exceeds said value, and decreasing the amount of the purging gas being supplied into the substrate transfer chamber when the measured humidity is less than said value, whereby the formation of particles by condensation on substrates within said container at said standby position is prevented.