Patent ID: 7617836

Claim:
A system for supplying a functional water to a process unit which treats a substrate using the functional water, the system comprising: a functional water generator generating the functional water; a functional water supply pipe supplying the functional water generated in the functional water generator to the process unit; a buffer tank connected with the functional supply pipe, for storing the functional water generated in the functional water generator; a concentration meter measuring the concentration of a gas dissolved in the functional water stored in the buffer tank; a functional water returning pipe having one end connected to the buffer tank and the other end connected to the functional water generator, the functional water returning pipe returning the functional water in the buffer tank to the functional water generator when the concentration of the gas dissolved in the functional water received stored in the buffer tank is out of a set concentration range; a distributor for distributing the functional water supplied from the functional water supply pipe to the process unit; and a functional water recovery pipe having one end connected to the distributor and the other end connected the functional water generator, the functional water recovery pipe recovering the functional water which is not distributed to the process unit to the functional water generator; wherein the functional water supply pipe includes: a first supply pipe having one end connected to the functional water generator and the other end connected to the buffer tank, the first supply pipe supplying the functional water generated in the functional water generator to the buffer; a second supply pipe having one end connected to the buffer tank and the other end connected to the distributor, the second supply pipe supplying the functional water stored in the buffer tank to the distributor; and a third supply pipe having one end connected to the distributor and the other end connected to the process unit, the third supply pipe supplying the functional water supplied to the distributor to the process unit.