Substrate processing method and substrate processing apparatus
Processing liquid is stored by a supply tank. The dissolved oxygen concentration of the processing liquid is measured. The dissolved oxygen concentration of the processing liquid in the supply tank is adjusted by supplying concentration adjusting gas having a concentration of inert gas higher than that of air into the supply tank in accordance with the dissolved oxygen concentration of the processing liquid measured. The processing liquid in the supply tank is supplied to a substrate. The processing liquid that has been supplied to the substrate is collected to the supply tank. Unnecessary gas that is a gas other than the concentration adjusting gas and dissolved in the processing liquid during the processing of the substrate is decreased from the processing liquid before the processing liquid is collected to the supply tank.
1. A substrate processing method comprising:
a processing liquid storing step of storing a processing liquid by a supplying tank;
a dissolved oxygen concentration measuring step of measuring a dissolved oxygen concentration of the processing liquid;
a dissolved oxygen concentration adjusting step of adjusting the dissolved oxygen concentration of the processing liquid stored in the supplying tank by supplying a concentration adjusting gas having a concentration of inert gas higher than that of air into the supply tank in accordance with the dissolved oxygen concentration of the processing liquid measured in the dissolved oxygen concentration measuring step;
a processing liquid supplying step of supplying the processing liquid in the supplying tank to a substrate;
a processing liquid collecting step of collecting the processing liquid that has been supplied to the substrate into the supply tank; and
an unnecessary gas decreasing step of decreasing an unnecessary gas, that is a gas other than the concentration adjusting gas and dissolved in the processing liquid in the processing liquid supplying step, from the processing liquid before the processing liquid that has been supplied to the substrate is collected into the supply tank.
2. The substrate processing method according to claim 1 , wherein the unnecessary gas decreasing step includes a degassing step of decreasing a total amount of gas dissolved in the processing liquid before the processing liquid that has been supplied to the substrate is collected into the supply tank.
3. The substrate processing method according to claim 1 , wherein the unnecessary gas decreasing step includes a gas dissolving step of replacing the unnecessary gas dissolved in the processing liquid with the concentration adjusting gas by dissolving the concentration adjusting gas into the processing liquid before the processing liquid that has been supplied to the substrate is collected into the supply tank.
4. The substrate processing method according to claim 1 , wherein the processing liquid collecting step includes an intermediate collecting step of causing the processing liquid to flow into a collecting tank before the processing liquid that has been supplied to the substrate is collected into the supply tank, and
the unnecessary gas decreasing step includes a step of decreasing the unnecessary gas from the processing liquid in the collecting tank.
5. The substrate processing method according to claim 4 , wherein the unnecessary gas decreasing step includes a gas dissolving step of dissolving the concentration adjusting gas into the processing liquid in the collecting tank by supplying the concentration adjusting gas into the collecting tank.
6. The substrate processing method according to claim 1 , wherein the processing liquid collecting step includes an upstream collecting step of causing the processing liquid to flow into an upstream tank before the processing liquid that has been supplied to the substrate is collected into the supply tank, and a downstream collecting step of causing the processing liquid to flow from the upstream tank to a downstream tank before the processing liquid in the upstream tank is collected into the supply tank, and
the unnecessary gas decreasing step includes a degassing step of decreasing a total amount of gas dissolved in the processing liquid in the upstream tank, and a gas dissolving step of dissolving the concentration adjusting gas into the processing liquid in the downstream tank by supplying the concentration adjusting gas into the downstream tank.
7. The substrate processing method according to claim 1 , wherein the processing liquid collecting step includes an intermediate collecting step of causing the processing liquid to flow into a collecting tank before the processing liquid that has been supplied to the substrate is collected into the supply tank,
the substrate processing method further includes a liquid temperature determining step of determining whether or not a temperature of the processing liquid in the supply tank is not greater than a reference temperature,
the unnecessary gas decreasing step includes a step of decreasing the unnecessary gas from the processing liquid in the collecting tank when the temperature of the processing liquid is determined to be not greater than the reference temperature in the liquid temperature determining step, and
the processing liquid collecting step includes a step of sending the processing liquid in the collecting tank toward the supply tank without decreasing the unnecessary gas from the processing liquid in the collecting tank when the temperature of the processing liquid is determined to be greater than the reference temperature in the liquid temperature determining step.
8. The substrate processing method according to claim 1 , wherein the processing liquid collecting step includes an intermediate collecting step of causing the processing liquid to flow into a collecting tank before the processing liquid that has been supplied to the substrate is collected into the supply tank,
the substrate processing method further includes an unnecessary gas concentration measuring step of measuring a concentration of the unnecessary gas in the processing liquid before the processing liquid that has been supplied to the substrate is sent from the collecting tank toward the supply tank, and a concentration determining step of determining whether or not the concentration of the unnecessary gas in the processing liquid measured in the unnecessary gas concentration measuring step is not less than a reference concentration,
the unnecessary gas decreasing step includes a step of decreasing the unnecessary gas from the processing liquid in the collecting tank when the concentration of the unnecessary gas is determined to be not less than the reference concentration in the concentration determining step,
the processing liquid collecting step includes a step of sending the processing liquid in the collecting tank toward the supply tank without decreasing the unnecessary gas from the processing liquid in the collecting tank when the concentration of the unnecessary gas is determined to be less than the reference concentration in the concentration determining step.
9. The substrate processing method according to claim 1 , wherein
the processing liquid collecting step further includes
a first collecting step of causing the processing liquid to flow into a first upstream tank without causing the processing liquid to flow into a second tank that is connected in parallel to the first tank before the processing liquid that has been supplied to the substrate is collected into the supply tank, and
a second collecting step of causing the processing liquid to flow into the second upstream tank without causing the processing liquid to flow into the first tank before the processing liquid that has been supplied to the substrate is collected into the supply tank, and
the unnecessary gas decreasing step includes a first unnecessary gas decreasing step of decreasing the unnecessary gas from the processing liquid in the first upstream tank in parallel to the second collecting step, and a second unnecessary gas decreasing step of decreasing the unnecessary gas from the processing liquid in the second upstream tank in parallel to the first collecting step.