| 摘要 |
PROBLEM TO BE SOLVED: To provide a substrate processing apparatus which is capable of supplying pure water that is kept stable in nitrogen gas concentration. SOLUTION: A pure water feed pathway 3 is branched off, nitrogen gas is dissolved in pure water at a dissolution unit 4 to obtain nitrogen-rich pure water, and on the other hand, nitrogen gas is degassed from the pure water at a degassing unit 5 to generate nitrogen-poor pure water. The nitrogen gas concentrations C1 and C2 of the nitrogen gas-rich pure water and the nitrogen gas-poor pure water are successively measured. Provided that target nitrogen gas concentration and the total flow rate of the pure water are represented by C and V respectively, first pure water running through a first pure water valve 19 and the second pure water running through a second pure water valve 22 are mixed together so as to satisfy formulas, C1×X1+C2×X2=C×V and X1+X2=V, as the first pure water valve 19 and the second pure water valve 22 are adjusted to control the flow rate X1 of the first valve 19 and the flow rate X2 of the second valve 22 respectively, whereby the pure water having the target nitrogen concentration C can be stably supplied. COPYRIGHT: (C)2004,JPO |
