Patent ID: 8104948

Claim:
A processing liquid mixing apparatus, comprising: a mixing tank to mix a plurality of stock solutions; a flow controller provided in supply flow paths to control flow rates of the stock solutions flowing through the supply flow paths at predetermined flow rates, the supply flow paths each supplying the stock solutions from stock solution supply sources to the mixing tank; a flow detector to detect the flow rates of the stock solutions flowing through the supply flow paths; discharge valves provided between the flow controller of the supply flow paths and the mixing tank to discharge the stock solutions flowing through the supply flow paths to an outside; supply valves provided between the discharge valves of the supply flow paths and the mixing tank to open/close the supply flow paths; and a controller to close the supply valves of the supply flow paths and to open the discharge valves of the supply flow paths when the supply of the stock solutions to the mixing tank starts, and to close the discharge valves of the supply flow paths and to open the supply valves of the supply flow paths after all the flow rates of the stock solutions detected by the flow detector reach the predetermined flow rates.