Substrate processing apparatus and substrate processing method

1. A substrate processing apparatus comprising:

at least one nozzle unit configured to eject a processing liquid to a substrate,

wherein the at least one nozzle unit includes a conductive part for voltage application configured to be brought into contact with the processing liquid, and a voltage detection part or a current detection part configured to be brought into contact with the processing liquid,

wherein a non-conductive part is interposed between the conductive part for voltage application and the voltage detection part or between the conductive part for voltage application and the current detection part, and

wherein a voltage application part is connected to the conductive part for voltage application, and a voltage detector is installed in the voltage detection part or a current detector is installed in the current detection part.

2. The substrate processing apparatus of claim 1 , wherein the at least one nozzle unit further includes a pipe configured to supply the processing liquid, and a nozzle tip provided at a tip end of the pipe and configured to eject the processing liquid toward the substrate, and

wherein the nozzle tip functions as the conductive part for voltage application.

3. The substrate processing apparatus of claim 2 , wherein the voltage detection part includes a conductive part for voltage detection or the current detection part includes a conductive part for current detection, and wherein the voltage detector is connected to the conductive part for voltage detection to directly detect a voltage of the conductive part for voltage detection, or the current detector is connected to the conductive part for current detection to directly detect a current flowing in the conductive part for current detection.

4. The substrate processing apparatus of claim 2 , wherein the voltage detector is formed by a capacitance-type surface electrometer configured to indirectly detect a voltage of the voltage detection part.

5. The substrate processing apparatus of claim 2 , further comprising:

a control device configured to determine whether or not the processing liquid is present between the conductive part for voltage application and the voltage detection part or between the conductive part for voltage application and the current detection part based on a signal from the voltage detector or the current detector.

6. The substrate processing apparatus of claim 1 , wherein the voltage detection part includes a conductive part for voltage detection or the current detection part includes a conductive part for current detection, and wherein the voltage detector is connected to the conductive part for voltage detection to directly detect a voltage of the conductive part for voltage detection, or the current detector is connected to the conductive part for current detection to directly detect a current flowing in the conductive part for current detection.

7. The substrate processing apparatus of claim 1 , wherein the voltage detector is formed by a capacitance-type surface electrometer configured to indirectly detect a voltage of the voltage detection part.

8. The substrate processing apparatus of claim 1 , further comprising:

a control device configured to determine whether or not the processing liquid is present between the conductive part for voltage application and the voltage detection part or between the conductive part for voltage application and the current detection part based on a signal from the voltage detector or the current detector.

9. The substrate processing apparatus of claim 8 , wherein the conductive part for voltage application includes a plurality of conductive part elements for voltage application with additional non-conductive parts being interposed between adjacent ones among the conductive part elements for voltage application, and

wherein the control device is further configured to obtain an interface of the processing liquid in the at least one nozzle unit based on a signal from the voltage detector or the current detector.

10. The substrate processing apparatus of claim 9 , wherein a processing liquid supply system including an opening and closing valve and a drain valve provided at a side of an outlet of the opening and closing valve is connected to an upstream side of the at least one nozzle unit, and a drain line is connected to the drain valve, and

wherein when stopping ejection of the processing liquid, the control device closes the opening and closing valve and opens the drain valve such that the processing liquid is discharged from the drain line, and obtains the interface of the processing liquid based on the signal from the voltage detector or the current detector.

11. The substrate processing apparatus of claim 10 , wherein the control device obtains a draining speed of the processing liquid based on the interface of the processing liquid.

12. The substrate processing apparatus of claim 8 , wherein a processing liquid supply system including an opening and closing valve and a drain valve provided at a side of an outlet of the opening and closing valve is connected to an upstream side of the at least one nozzle unit, and a drain line is connected to the drain valve, and

wherein the control device closes the opening and closing valve and the drain valve while the substrate processing apparatus is on standby, and opens the drain valve to discharge the processing liquid from the drain line when the processing liquid is determined to be present between the conductive part for voltage application and the voltage detection part or between the conductive part for voltage application and the current detection part.

13. The substrate processing apparatus of claim 1 , wherein the at least one nozzle unit is installed with a plurality of nozzle units.

14. A substrate processing method using a substrate processing apparatus that includes a nozzle unit configured to eject a processing liquid to a substrate and a control device, wherein the nozzle unit includes a conductive part for voltage application configured to be brought into contact with the processing liquid, and a voltage detection part or a current detection part configured to be brought into contact with the processing liquid, wherein a non-conductive part is interposed between the conductive part for voltage application and the voltage detection part or between the conductive part for voltage application and the current detection part, wherein a voltage application part is connected to the conductive part for voltage application, and a voltage detector is installed in the voltage detection part or a current detector is installed in the current detection part, and wherein a processing liquid supply system is provided at an upstream side of the nozzle unit, the method comprising:

ejecting the processing liquid from the nozzle unit to the substrate by operating the processing liquid supply system by the control device;

stopping the ejection of the processing liquid from the nozzle unit to the substrate by operating the processing liquid supply system by the control device;

applying a voltage from the voltage application part to the conductive part for voltage application by the control device; and

determining, by the control device, whether or not the processing liquid is present between the conductive part for voltage application and the voltage detection part by detecting a voltage of the voltage detection part by the voltage detector, or determining, by the control device, whether or not the processing liquid is present between the conductive part for voltage application and the current detection part by detecting a current flowing in the current detection part by the current detector.

15. The substrate processing method of claim 14 , wherein the conductive part for voltage application includes a plurality of conductive part elements for voltage application with additional non-conductive parts being interposed between adjacent ones among the conductive part elements for voltage application, and

wherein the control device is configured to obtain an interface of the processing liquid in the nozzle unit based on a signal from the voltage detector or the current detector.

16. The substrate processing method of claim 14 , wherein the processing liquid supply system includes an opening and closing valve and a drain valve provided at a side of an outlet of the opening and closing valve, and a drain line is connected to the drain valve, and

wherein the control device closes the opening and closing valve and the drain valve while the substrate processing apparatus is on standby, and opens the drain valve to discharge the processing liquid from the drain line when the processing liquid is determined to be present between the conductive part for voltage application and the voltage detection part or between the conductive part for voltage application and the current detection part.

17. The substrate processing method of claim 14 , wherein the processing liquid supply system includes an opening and closing valve and a drain valve provided at a side of an outlet of the opening and closing valve, and a drain line is connected to the drain valve, and

wherein in the stopping the ejection of the processing liquid, the control device closes the opening and closing valve and opens the drain valve such that the processing liquid is discharged from the drain line, and obtains an interface of the processing liquid based on a signal from the voltage detector or the current detector.

18. The substrate processing method of claim 17 , wherein the control device obtains a draining speed of the processing liquid based on the interface of the processing liquid.