Patent ID: 7237562

Claim:
A substrate processing apparatus comprising: (a) a processing part for performing a predetermined process of a substrate with a processing liquid; (b) a processing liquid supply path for supplying a processing liquid to said processing part, said processing liquid supply path having: (b-1) a first measuring element for obtaining a first measured concentration value by measuring a concentration of an inert gas of said processing liquid in a first state, said concentration of said inert gas of said processing liquid in said first state being not adjusted, (b-2) a concentration change element comprising first and second groups of a plurality of hollow fiber type separation membranes housed in a single body for changing said processing liquid into a second state by changing said concentration of said inert gas of said processing liquid in said first state, and (b-3) a second measuring element for obtaining a second measured concentration value by measuring said concentration of said inert gas of said processing liquid in said second state; and (c) a controlling element for controlling said concentration of said inert gas of said processing liquid in said second state toward a predetermined target concentration by controlling said concentration change element, such that said concentration of said inert gas of said processing liquid is caused to be changed by both dissolving said inert gas in said processing liquid through said first group of said plurality of hollow fiber type separation membranes and degassing said inert gas from said processing liquid through said second group of said plurality of hollow fiber type separation membranes based on said first and second measured concentration values.