Wafer cleaning water supply system and wafer cleaning water supply method

A method of supplying wafer cleaning water, the method comprising:

• dissolving a chemical agent in ultrapure water in a wafer cleaning water production unit thereby to produce wafer cleaning water having a predetermined concentration of the chemical agent;
• feeding the wafer cleaning water, by a replenishment pipe connected to the wafer cleaning water production unit and a circulation-type cleaning water supply pipe, to the circulation-type cleaning water supply pipe thereby to supply the wafer cleaning water to a use point;
• and
• circulating, by the circulation-type cleaning water supply pipe, the wafer cleaning water unused at the use point and reusing the unused wafer cleaning water,
• wherein
• the circulation-type cleaning water supply pipe includes a supply side that supplies the wafer cleaning water to the use point and a recovery side that recovers the unused wafer cleaning water from the use point;
• the supply side and the recovery side form a circulation path between a connection portion of the circulation-type cleaning water supply pipe to the replenishment pipe and the use point;
• no reservoir is provided in the circulation path,
• an index for calculating a usage amount of cleaning water is measured at the use point of the wafer cleaning water that circulates through the circulation-type cleaning water supply pipe;
• and
• a replenishment amount of the wafer cleaning water based on the measurement result is controlled by a control means.