Megasonic cleaner and dryer

• US 6,754,980 B2
• Filed: 06/12/2002
• Issued: 06/29/2004
• Est. Priority Date: 06/12/2001
• Status: Expired due to Term

• Current Assignee: Akrion Technologies Incorporated (Akrion Incorporated), Interuniversitair Micro-Electronica Centrum VZW (IMEC International)
• Original Assignee: Goldfinger Technologies LLC (Akrion Incorporated)
• Inventors: Nicolosi, Thomas J. Jr., Mertens, Paul, Lauerhaas, Jeffrey M., Fyen, William
• Primary Examiner(s): Bennett, Henry
• Assistant Examiner(s): NGUYEN, CAMTU TRAN
• Application Number:
  US10/171,426
• Publication Number:
  US 20020185152A1
• Time in Patent Office: 748 Days
• Field of Search: 134/1.3, 134/95.2, 134/184, 134/902, 134/1, 134/95.3, 134/103.2, 134/147, 134/148, 134/151, 134/153, 134/198, 134/157, 134/187, 343/17, 343/12, 345/94, 346/67, 343/37, 344/67, 34/58, 34/72
• US Class Current: 34/594
• CPC Class Codes: H01L 21/67034 for drying
• CPC Class Codes: H01L 21/67051 using mainly spraying means, e.g. nozzles
• CPC Class Codes: Y10S 134/902 Semiconductor wafer

Abstract

An apparatus for drying a generally flat substrate that has been cleaned has a rotatable support for supporting the substrate, a substrate drying assembly, and a controller. The substrate drying assembly includes a substrate drying assembly support arm, an outlet for applying liquid to an upper surface of the substrate, and an outlet for applying a drying vapor to the upper surface of the substrate. The substrate drying assembly is configured to position the liquid applying outlet and to position the vapor applying outlet above a portion of the substrate. The controller causes the substrate drying assembly to be retracted over the upper surface of the substrate at a faster rate near a center of the substrate than near a periphery of the substrate.

Claims

1. A method of cleaning and drying a generally flat substrate positioned on a rotatable support comprising the steps of:

positioning a transmitter closely spaced above an upper surface of the substrate;

applying fluid to the substrate to create a meniscus between the transmitter and the rotating substrate;

applying megasonic energy to the transmitter to cause it to propagate megasonic energy through the meniscus to the substrate to loosen particles on the substrate while the substrate is rotating at a first rate;

retracting the transmitter; and

moving a substrate drying assembly support arm of a substrate drying assembly into position closely spaced above the substrate, the substrate drying assembly including an outlet for applying liquid to the upper surface of the substrate and including an outlet for applying a drying vapor to the upper surface of the substrate;

wherein the substrate drying assembly support arm is moved into place as the transmitter is being retracted.

2. A method of cleaning and drying a generally flat substrate positioned on a rotatable support comprising the steps of:

cleaning a surface of the substrate;

moving a substrate drying assembly support arm of a substrate drying assembly into position closely spaced above the substrate, said substrate drying assembly including an outlet for applying liquid to the upper surface of the substrate and including an outlet for applying a drying vapor to the upper surface of the substrate; and

retracting the substrate drying assembly support arm radially outwardly at a retraction rate to a periphery of the substrate while applying liquid to the substrate through the liquid outlet and following that with said drying vapor being applied to the substrate to dry the substrate;

wherein the step of retracting the substrate drying assembly support arm comprises retracting at a substrate-center retraction rate near the center of the substrate and a substrate-periphery retraction rate near the periphery of the substrate, the substrate-center retraction rate being faster than the substrate-periphery retraction rate.

3. The method of claim 2, further comprising:

positioning the liquid applying outlet approximately over a center of the substrate;

applying liquid to the substrate through the liquid applying outlet;

positioning the drying vapor outlet approximately over the center of the substrate; and

applying tensioactive vapor to the substrate as the substrate is rotating to thereby dry the center of the substrate due to the rotation and by the action of the vapor on the liquid;

wherein the positioning the liquid applying outlet, applying liquid, positioning the drying vapor outlet, and applying tensioactive vapor steps are performed before the retracting step.

4. A method of cleaning and drying a generally flat substrate positioned on a rotatable support comprising the steps of:

cleaning a surface of the substrate;

moving a substrate drying assembly support arm of a substrate drying assembly into position closely spaced above the substrate, said substrate drying assembly including an outlet for applying liquid to the upper surface of the substrate and including an outlet for applying a drying vapor to the upper surface of the substrate; and

retracting the substrate drying assembly support arm radially outwardly at a retraction rate to a periphery of the substrate while applying liquid to the substrate through the liquid outlet and following that with said drying vapor being applied to the substrate to dry the substrate;

wherein at a location between the center of the substrate and the periphery of the substrate, the retraction rate of the substrate drying assembly support arm is greater than the retraction rate near the center of the substrate and greater than the retraction rate near the periphery of the substrate.

5. The method of claim 4, further comprising

positioning the liquid applying outlet approximately over a center of the substrate;

applying liquid to the substrate through the liquid applying outlet;

positioning the drying vapor outlet approximately over the center of the substrate; and

applying tensioactive vapor to the substrate as the substrate is rotating to thereby dry the center of the substrate due to the rotation and by the action of the vapor on the liquid;

wherein the positioning the liquid applying outlet, applying liquid, positioning the drying vapor outlet; and

applying tensioactive vapor steps are performed before the retracting step.

6. A method of cleaning and drying a generally flat substrate positioned on a rotatable support comprising the steps of:

cleaning a surface of the substrate;

moving a substrate drying assembly support arm of a substrate drying assembly into position closely spaced above the substrate, said substrate drying assembly including an outlet for applying liquid to the upper surface of the substrate and including an outlet for applying a drying vapor to the upper surface of the substrate; and

retracting the substrate drying assembly support arm radially outwardly at a retraction rate to a periphery of the substrate while applying liquid to the substrate through the liquid outlet and following that with said drying vapor being applied to the substrate to complete the drying action of the substrate;

wherein the substrate is rotated in a range between about 50 rpm and about 1,000 rpm while the retraction rate is in the range between about 1 mm per second and about 20 mm per second.

7. The method of claim 6, further comprising

positioning the liquid applying outlet approximately over a center of the substrate;

applying liquid to the substrate through the liquid applying outlet;

positioning the drying vapor outlet approximately over the center of the substrate; and

applying tensioactive vapor to the substrate as the substrate is rotating to thereby dry the center of the substrate due to the rotation and by the action of the vapor on the liquid;

wherein the positioning the liquid applying outlet, applying liquid, positioning the drying vapor outlet; and

applying tensioactive vapor steps are performed before the retracting step.

8. The method of claim 6, wherein during the drying operation of the upper surface of the substrate the substrate is rotated in a range between about 200 rpm and about 1,000 rpm while the retraction rate is in the range between about 4 mm per second and about 9 mm per second.

9. The method of claim 6, wherein the step of retracting the substrate drying assembly support arm comprises using a stepper motor to retract the substrate drying assembly support arm.

10. The method of claim 6, wherein the retraction rate comprises a range of rates up to and including a maximum rate, and wherein the maximum rate is increased as the rate at which the substrate is rotated is increased by about 0.5 mm per second for about each 100 increase in the revolutions per minute of the rotation of the substrate.

11. The method of claim 10, wherein the maximum rate at which the drying arm is retracted is about 5 mm/sec when the rate of rotation of the substrate is about 300 revolutions per minute.

12. A method of drying a generally flat substrate that has been cleaned, the substrate positioned on a rotatable support, the method comprising the steps of:

moving a substrate drying assembly support arm into position closely spaced above the substrate, the substrate drying assembly including an outlet for applying liquid to an upper surface of the substrate and including an outlet for applying a drying vapor to the upper surface of the substrate;

retracting the substrate drying assembly support arm radially outwardly at a retraction rate to a periphery of the substrate while applying liquid to the substrate through the liquid applying outlet and following that with said drying vapor being applied to the substrate to complete the drying action of the substrate;

wherein the step of retracting the substrate drying assembly support arm comprises retracting at a substrate-center retraction rate near the center of the substrate and a substrate-periphery retraction rate near the periphery of the substrate, the substrate-center retraction rate being faster than the substrate-periphery retraction rate.

13. The method of claim 12, further comprising:

positioning the liquid applying outlet approximately over a center of the substrate;

applying liquid to the substrate through the liquid applying outlet;

positioning the drying outlet approximately over the center of the substrate; and

applying tensioactive vapor to the substrate as the substrate is rotating to thereby dry the center of the substrate due to the rotation and by the action of the vapor on the liquid;

wherein the positioning the liquid applying outlet, applying liquid, positioning the drying vapor outlet; and

applying tensioactive vapor steps are performed before the retracting step.

14. The method of claim 12, wherein at a location between the center of the substrate and the periphery of the substrate, the step of retracting the substrate drying assembly support arm comprises retracting at a rate faster than the substrate-center retraction rate and faster than that the substrate-periphery retraction rate.

15. The method of claim 12, further comprising the step of holding the substrate drying assembly position constant at the center of the substrate while the center is dried.

16. The method of claim 12, further comprising the steps of stopping the application of liquid to the upper surface of the substrate near the periphery of the substrate, and stopping the application of drying vapor to the substrate after the application of liquid to the substrate is stopped.

17. The method of claim 12, further comprising the step of greatly increasing the rate of rotation of the substrate at the completion of the drying of the upper surface of the substrate so as to dry a lower surface of the substrate by centrifugal action.

18. The method of claim 12, further comprising the steps of stopping the retraction of the substrate drying assembly support arm near the periphery, stopping the application of liquid to the upper surface of the substrate near the periphery of the substrate, and stopping the application of drying vapor to the substrate after the application of liquid to the substrate is stopped.

19. The method of claim 18, wherein the step of applying drying vapor to the substrate is stopped before the substrate drying assembly is retracted beyond the outer periphery of the substrate.

20. A method of cleaning and drying a generally flat substrate positioned on a rotatable support comprising the steps of:

cleaning a surface of the substrate;

selecting at least one of a blanket substrate drying process window if the substrate has a blanket portion or a patterned substrate drying process window if the substrate has a patterned portion;

moving a substrate drying assembly support arm into position closely spaced above the substrate, the substrate drying assembly including an outlet for applying liquid to the surface of the substrate and including an outlet for applying a drying vapor to the surface of the substrate;

rotating the substrate; and

retracting the substrate drying assembly support arm radially outwardly according to the selected drying process window to a periphery of the substrate while applying liquid to the substrate through the liquid applying outlet and following that with said drying vapor being applied to the substrate to dry the substrate.

21. The method of claim 20, further comprising:

positioning the liquid applying outlet approximately over a center of the substrate;

applying liquid to the substrate through the liquid applying outlet;

positioning the drying vapor outlet approximately over the center of the substrate;

applying tensioactive vapor to the substrate as the substrate is rotating to thereby dry the center of the substrate due to the rotation and by the action of the vapor on the liquid;

wherein the positioning the liquid applying outlet, applying liquid, positioning the drying vapor outlet, and applying tensioactive vapor steps are performed before the retracting step.

22. The method of claim 20, wherein the blanket substrate drying process window comprises a range of retraction rates up to and including a maximum rate, and wherein the maximum rate is increased as the rate at which the substrate is rotated is increased by about 0.5 mm per second for about each 100 increase in the revolutions per minute of the rotation of the substrate, and wherein the maximum retraction rate is about 5 mm/sec when the rate of rotation of the substrate is about 300 revolutions per minute.

23. The method of claim 20, wherein the patterned substrate drying process window comprises the range of retraction rates up to and including a maximum rate, and wherein the maximum retraction rate is increased as the rate at which the substrate is rotated is increased by about 0.5 mm per second for about each 100 increase in the revolutions per minute of the rotation of the substrate, and wherein the maximum retraction rate is retracted is about 4 mm/sec when the rate of rotation of the substrate is about 300 revolutions per minute.

24. The method of claim 20, wherein during the drying operation of the upper surface of the substrate the substrate is rotated in a range between 50 rpm and 1,000 rpm while the retraction rate of the drying arm is in the range between about 1 and about 20 mm per second.

25. The method of claim 20, wherein during the drying operation of the upper surface of the substrate the substrate is rotated in a range between 200 rpm and 1,000 rpm while the retraction rate of the drying arm is in the range between about 4 and about 9 mm per second.

26. The method of claim 20, wherein the step of retracting the substrate drying assembly support arm comprises using a stepper motor to retract the substrate drying assembly support arm.

27. The method of claim 20, wherein the retraction rate comprises a range of rates up to and including a maximum rate, and wherein the maximum rate is increased as the rate at which the substrate is rotated is increased at a rate of at a rate of about 0.5 mm per second for each 100 increase in the revolutions per minute of the rotation of the substrate.

28. The method of claim 27, wherein the maximum rate at which the drying arm is retracted is 5 mm/sec when the rate of rotation of the substrate is 300 revolutions per minute.

29. The method of claim 20, wherein the surface comprises an upper surface of the substrate.

30. A method of cleaning and drying a generally flat substrate positioned on a rotatable support comprising the steps of:

cleaning the substrate;

selecting at least one of a blanket substrate drying process window if the substrate has a blanket portion or a patterned substrate drying process window if the substrate has a patterned portion;

moving a substrate drying assembly support arm into position closely spaced from the substrate, the substrate drying assembly including an outlet for applying liquid to the substrate and including an outlet for applying a drying vapor to the substrate;

rotating the substrate; and

retracting the substrate drying assembly support arm radially outwardly according to the selected drying process window to a periphery of the substrate while applying liquid to the substrate through the liquid applying outlet and following that with said drying vapor being applied to the substrate to dry the substrate.

31. The method of claim 30, wherein the cleaning step further comprises:

applying a liquid to an upper surface and a lower surface of the substrate; and

directing sonic energy through the liquid to the substrate.

32. The method of claim 31, wherein the directing step further comprises directing sonic energy through the liquid on the upper surface of the substrate.

33. The method of claim 32, wherein the moving step further comprises moving the substrate drying assembly support arm into position closely spaced above the substrate.

34. The method of claim 30, wherein the cleaning step further comprises:

applying a liquid to a first surface of the substrate and to a second surface opposite the first surface of the substrate to create a thin film of liquid on at least one of said first and said second surfaces;

positioning a transmitter close to the substrate in contact with said thin film; and

applying sonic energy to the substrate through the thin film.

35. The method of claim 34, wherein the applying sonic energy step further comprises applying sonic energy through the substrate to loosen particles on both sides of the substrate simultaneously.

36. The method of claim 34, wherein the positioning step further comprises positioning the transmitter above the substrate.