Apparatus and method for deposition of an electrophoretic emulsion

• US 20030079989A1
• Filed: 09/03/2002
• Published: 05/01/2003
• Est. Priority Date: 08/31/2001
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Semitool Incorporated (Applied Materials Incorporated)
• Inventors: Hanson, Kyle M., Klocke, John
• Granted Patent: US 7,150,816 B2
• Time in Patent Office: Days
• US Class Current: 204/471
• CPC Class Codes: C25D 13/00 Electrophoretic coating characterised by the process C25D15/00 takes precedence; compositions for electrophoretic coating C09D5/44
• CPC Class Codes: C25D 13/12 characterised by the article coated
• CPC Class Codes: C25D 13/22 Servicing or operating apparatus or multistep processes
• CPC Class Codes: C25D 17/001 Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• CPC Class Codes: G03F 7/164 using electric, electrostatic or magnetic means; powder coating

Abstract

The present invention provides a system that enables the use of electrophoretic resists in the microfabrication industry for the production of microelectronic devices and is of sufficiently high quality to be used as a replacement for, or supplement to, current photoresist deposition technology. This system enables the application of electrophoretic resists in automated equipment that meets the standards for cleanliness and production throughput desired by the microelectronic fabrication industry. The system, apparatus and method, for providing electrophoretic resist (“EPR”) layers on microelectronic workpieces for the microfabrication of microelectronic devices comprises a deposition station for receiving a microelectronic workpiece and depositing a layer of electrophoretic photoresist (EPR) thereon, a workpiece handling apparatus, and a control unit coupled to the workpiece handling apparatus and the deposition station for coordinating the processing of the workpiece in accordance with a predetermined sequence and set of processing parameters.

Claims

1. A reactor base of an electrophoretic deposition station for depositing electrophoretic material onto a workpiece, comprising:

an overflow cup;

a processing cup in the overflow cup, the processing cup having an inlet coupled to a supply conduit for an electrophoretic emulsion and a weir defining a processing zone;

a gas control system in the processing cup, the gas control system being configured to inhibit bubbles from residing on a workpiece oriented at least substantially horizontal in the processing zone; and

an electrode in the processing cup.

2. The reactor base of claim 1 further comprising a reservoir in the reactor base below the overflow cup, a thermal element in the reservoir, and a drainage passage between the overflow cup and the reservoir through which an EPE fluid can flow downward.

3. The reactor base of claim 1 further comprising an ultrafilter configured to separate an EPE into a permeate solution and a concentrated EPE.

4. The reactor base of claim 1 wherein the gas control system comprises an annular bubble trap extending around an interior portion of the processing cup and projecting radially inwardly above the electrode, and wherein the head further comprises a rotor for rotating the workpiece holder in the processing position.

5. The reactor base of claim 1 wherein the gas control system comprises an annular bubble trap having a ledge extending around the interior portion of the processing cup and projecting radially inwardly above the electrode, and a vent through the processing cup located under a portion of the ledge through which bubbles can flow out of the processing cup before reaching the processing zone, and wherein the head further comprises a rotor for rotating the workpiece holding in the processing position.

6. The reactor base of claim 5 wherein the ledge has a lower surface that projects radially inwardly and downwardly from the processing cup.

7. The reactor base of claim 1 wherein the gas control system comprises a diffuser at the inlet of the processing cup that directs a flow component of an EPE upwardly toward a central location of the processing zone.

8. The reactor base of claim 1 wherein:

the electrode comprises an annular electrode having a vertically oriented side wall and an opening aligned with the processing zone through which an EPE fluid can flow; and

the gas control system comprises a diffuser at the inlet of the processing cup that directs a first flow component of the EPE fluid toward a central location of the processing zone and a second flow component of the EPE fluid upward and radially outward toward the side wall of the electrode.

9. The reactor base of claim 1 wherein:

the electrode comprises an annular electrode having a vertically oriented side wall and an opening aligned with the processing zone through which an EPE fluid can flow; and

the gas control system comprises a diffuser at the inlet of the processing cup that directs a first flow component of the EPE fluid toward a central location of the processing zone and a second flow component of the EPE fluid upward and radially outward toward the side wall of the electrode, and a bubble trap having a ledge extending around an interior portion of the processing cup and projecting radially inward above the electrode and a vent through the processing cup located under the ledge.

10. A reactor base of an electrophoretic deposition reactor for depositing electrophoretic material onto a workpiece having a first diameter, comprising:

a reservoir for containing an EPE;

a thermal element in the reservoir for maintaining the EPE at a desired temperature;

a reactor vessel above the reservoir, the reactor vessel comprising an overflow cup;

a processing cup in the overflow cup, the processing cup having an inlet coupled to a supply conduit for an electrophoretic emulsion and a weir having a diameter larger than the first diameter of the workpiece to define a processing zone for a single-workpiece oriented at least substantially horizontal; and

an electrode in the processing cup; and

a filter in fluid communication with EPE flowing through the reactor vessel and/or the reservoir, the filter being configured to separate the EPE into a permeate solution and a concentrated EPE solution.

11. The reactor base of claim 10 further comprising a gas control system configured to inhibit bubbles from residing on a horizontally oriented workpiece in the processing zone.

12. The reactor base of claim 11 further comprising an in-situ ancillary processing assembly above the processing cup, the in-situ processing assembly having a nozzle to direct a flow of an ancillary processing fluid different than the EPE fluid radially inward and a collector to catch spent ancillary processing fluid above the weir.

13. The reactor base of claim 11 wherein the gas control system comprises an annular bubble trap extending around an interior portion of the processing cup and projecting radially inwardly above the electrode, and wherein the head further comprises a rotor for rotating the workpiece holder in the processing position.

14. The reactor base of claim 11 wherein the gas control system comprises an annular bubble trap having a ledge extending around the interior portion of the processing cup and projecting radially inwardly above the electrode, and a vent through the processing cup located under a portion of the ledge through which bubbles can flow out of the processing cup before reaching the processing zone, and wherein the head further comprises a rotor for rotating the workpiece holder in the processing position.

15. The reactor base of claim 14 wherein the ledge has a lower surface that projects radially inwardly and downwardly from the processing cup.

16. The reactor base of claim 11 wherein the gas control system comprises a diffuser at the inlet of the processing cup that directs a flow component of an EPE upwardly toward a central location of the processing zone.

17. The reactor base of claim 11 wherein:

the electrode comprises an annular electrode having a vertically oriented side wall and an opening aligned with the processing zone through which an EPE fluid can flow; and

the gas control system comprises a diffuser at the inlet of the processing cup that directs a first flow component of the EPE fluid toward a central location of the processing zone and a second flow component of the EPE fluid upward and radially outward toward the side wall of the electrode.

18. The reactor base of claim 11 wherein:

the electrode comprises an annular electrode having a vertically oriented side wall and an opening aligned with the processing zone through which an EPE fluid can flow; and

the gas control system comprises a diffuser at the inlet of the processing cup that directs a first flow component of the EPE fluid toward a central location of the processing zone and a second flow component of the EPE fluid upward and radially outward toward the side wall of the electrode, and a bubble trap having a ledge extending around an interior portion of the processing cup and projecting radially inward above the electrode and a vent through the processing cup located under the ledge.

19. A reactor base of an electrophoretic deposition reactor for depositing electrophoretic material onto a workpiece, comprising:

an overflow cup;

a processing cup in the overflow cup, the processing cup having an inlet coupled to a supply conduit for an electrophoretic emulsion and a weir defining a processing zone;

a gas control system in the processing cup, the gas control system being configured to inhibit bubbles from residing on a workpiece oriented at least substantially horizontal in the processing zone;

an electrode in the processing cup; and

an in-situ ancillary processing assembly above the overflow cup, the in-situ processing assembly having a nozzle to direct a flow of an ancillary processing fluid different than the EPE fluid radially inward and a collector to catch spent ancillary processing fluid above the weir.

20. The reactor base of claim 19 further comprising a reservoir in the reactor base below the overflow cup, a thermal element in the reservoir, and a drainage passage between the overflow cup and the reservoir through which an EPE fluid can flow downward.

21. The reactor base of claim 19 further comprising an ultrafilter configured to separate an EPE into a permeate solution and a concentrated EPE.

22. The reactor base of claim 19 wherein the gas control system comprises an annular bubble trap extending around an interior portion of the processing cup and projecting radially inwardly above the electrode, and wherein the head further comprises a rotor for rotating the workpiece holder in the processing position.

23. The reactor base of claim 19 wherein the gas control system comprises an annular bubble trap having a ledge extending around the interior portion of the processing cup and projecting radially inwardly above the electrode, and a vent through the processing cup located under a portion of the ledge through which bubbles can flow out of the processing cup before reaching the processing zone, and wherein the head further comprises a rotor for rotating the workpiece holder in the processing position.

24. The reactor base of claim 23 wherein the ledge has a lower surface that projects radially inwardly and downwardly from the processing cup.

25. The reactor base of claim 19 wherein the gas control system comprises a diffuser at the inlet of the processing cup that directs a flow component of an EPE upwardly toward a central location of the processing zone.

26. The reactor base of claim 19 wherein:

the electrode comprises an annular electrode having a vertically oriented side wall and an opening aligned with the processing zone through which an EPE fluid can flow; and

the gas control system comprises a diffuser at the inlet of the processing cup that directs a first flow component of the EPE fluid toward a central location of the processing zone and a second flow component of the EPE fluid upward and radially outward toward the side wall of the electrode.

27. The reactor base of claim 19 wherein:

the electrode comprises an annular electrode having a vertically oriented side wall and an opening aligned with the processing zone through which an EPE fluid can flow; and

the gas control system comprises a diffuser at the inlet of the processing cup that directs a first flow component of the EPE fluid toward a central location of the processing zone and a second flow component of the EPE fluid upward and radially outward toward the side wall of the electrode, and a bubble trap having a ledge extending around an interior portion of the processing cup and projecting radially inward above the electrode and a vent through the processing cup located under the ledge.

28. A method of processing a microelectronic workpiece, comprising depositing a layer of electrophoretic material onto a processing side of the workpiece by contacting the processing side of the workpiece with a bath of an electrophoretic emulsion while isolating at least a region of the workpiece from contacting the electrophoretic emulsion and establishing an electrical field in the bath of electrophoretic emulsion.

29. The method of claim 28 wherein contacting the processing side of the workpiece with a bath of an electrophoretic emulsion comprises holding the workpiece at least substantially horizontal with the processing side in contact with the electrophoretic emulsion.

30. The method of claim 28 wherein contacting the processing side of the workpiece with a bath of an electrophoretic emulsion comprises holding the workpiece at least substantially horizontal with the processing side in contact with the electrophoretic emulsion and rotating the workpiece.

31. The method of claim 28 wherein isolating at least a region of the workpiece from contacting the electrophoretic emulsion comprises sealing a perimeter portion of the processing side of the workpiece.

32. The method of claim 28 further comprising inhibiting gases from residing on the processing side of the workpiece.

33. The method of claim 32 wherein inhibiting gases from residing on the processing side of the workpiece comprises removing bubbles from the electrophoretic emulsion before the bubbles reach the processing side of the workpiece.

34. The method of claim 32 wherein inhibiting gases from residing on the processing side of the workpiece comprises sweeping bubbles away from the processing side of the workpiece.

35. The method of claim 32 wherein inhibiting gases from residing on the processing side of the workpiece comprises directing a first flow component toward a central region of the workpiece, directing a second flow component upward and radially outward toward an annular electrode, and trapping bubbles entrained in the second flow component under a ledge overhanging the electrode.

36. The method of claim 28 further comprising rinsing the workpiece with a permeate solution in-situ within the deposition station.

37. The method of claim 28 further comprising rinsing the workpiece with a permeate solution in-situ within the deposition station by raising the workpiece out of the electrophoretic emulsion, impinging a stream of permeate solution against the workpiece, rotating the workpiece while impinging the stream of permeate solution, and collecting spent permeate solution flung from the wafer to maintain the spent permeate solution separate from the electrophoretic solution.