Clamshell apparatus for electrochemically treating semiconductor wafers

• US 6,156,167 A
• Filed: 11/13/1997
• Issued: 12/05/2000
• Est. Priority Date: 11/13/1997
• Status: Expired due to Term

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Patton, Evan E., Fetters, Wayne
• Primary Examiner(s): Gorgos, Kathryn
• Assistant Examiner(s): SMITH HICKS, ERICA D
• Application Number:
  US08/969,984
• Time in Patent Office: 1,118 Days
• Field of Search: 204/297 R, 204/212, 204/270
• US Class Current: 204/270
• 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: H01L 21/68721 characterised by edge clamping, e.g. clamping ring
• CPC Class Codes: H01L 21/68728 characterised by a plurality of separate clamping members, e.g. clamping fingers
• CPC Class Codes: H01L 21/68735 characterised by edge profile or support profile
• CPC Class Codes: H01L 21/68785 characterised by the mechanical construction of the susceptor, stage or support
• CPC Class Codes: H01L 21/68792 characterised by the construction of the shaft

Abstract

An apparatus for electroplating a wafer surface includes a cup having a central aperture defined by an inner perimeter, a compliant seal adjacent the inner perimeter, contacts adjacent the compliant seal and a cone attached to a rotatable spindle. The compliant seal forms a seal with the perimeter region of the wafer surface preventing plating solution from contaminating the wafer edge, wafer backside and the contacts. As a further measure to prevent contamination, the region behind the compliant seal is pressurized. By rotating the wafer during electroplating, bubble entrapment on the wafer surface is prevented. Further, the contacts can be arranged into banks of contacts and the resistivity between banks can be tested to detect poor electrical connections between the contacts and the wafer surface.

Claims

1. An apparatus for treating a surface of a substrate comprising:

a cup having a central aperture defined by an inner perimeter;

a compliant seal adjacent said inner perimeter, said compliant seal being for pressing against said substrate;

a plurality of electrical contacts adjacent said compliant seal for making electrical contact with said substrate;

a cone attached to a rotatable spindle, wherein said cone and said cup define a first cavity, said plurality of contacts being located in said first cavity;

said first cavity containing a pressurized gas.

2. The apparatus of claim 1 further comprising:

bearings for supporting said spindle; and

a motor for rotating said spindle.

3. The apparatus of claim 1 further comprising:

one or more slip rings on said spindle; and

one or more brushes for contact with corresponding ones of said slip rings.

4. The apparatus of claim 1 further comprising a rotary union mounted to said spindle.

5. The apparatus of claim 1 further comprising a rack which allows vertical movement of said apparatus.

6. The apparatus of claim 1 wherein said cone is in abutting contact with said cup, said cone and said cup defining a second cavity therebetween, said apparatus further comprising a vacuum line for evacuating said second cavity.

7. The apparatus of claim 6 further comprising a first O-ring and a second O-ring, said second cavity being further defined by said first O-ring and said second O-ring.

8. The apparatus of claim 1 wherein said compliant seal is formed of a material having a shore A hardness in the range of 60-80.

9. The apparatus of claim 8 wherein said compliant seal is formed of a material consisting of synthetic rubber.

10. The apparatus of claim 1 wherein said cone comprises a pressing surface for pressing said substrate against said compliant seal.

11. The apparatus of claim 10 further comprising a third O-ring located in a channel of said pressing surface, said third O-ring extending beyond the plane defined by said pressing surface.

12. The apparatus of claim 1 further comprising a contact strip comprising said plurality of contacts and a base section, said base section being attached to said cup.

13. The apparatus of claim 12 wherein said contact strip further comprises a tab, said apparatus further comprising a sliding contact extending from said cone aligned to make contact with said tab when said cone and said cup are in abutting contact.

14. The apparatus of claim 12 wherein said plurality of contacts are bent from said base section, said contacts having a normal resting position, said contacts exerting a spring force when displaced from said normal resting position.

15. The apparatus of claim 1 further comprising a thief electrode mounted on an outer surface of said cup.

16. The apparatus of claim 1 further comprising at least one alignment pin, said cup and said cone each having at least one corresponding alignment hole.

17. The apparatus of claim 1 wherein said plurality of contacts are grouped into at least two banks of contacts, each of said banks being electrically isolated for the other of said banks.

18. The apparatus of claim 1 further comprising snubbers for centering said substrate in said cup.

19. The apparatus of claim 1 wherein said cup is attached to said spindle, said apparatus further comprising a shaft extending into said spindle, said cone capable of vertical movement along said shaft.

20. The apparatus of claim 19 further comprising an air actuated cylinder which moves said cone along said shaft.

21. The apparatus of claim 19 further comprising at least one lead extending from said spindle to said cup, said at least one lead being electrically connected to said plurality of contacts.

22. The apparatus of claim 19 further comprising at least one poppet valve on said cone.

23. The apparatus of claim 1 wherein said cup comprises an electrically insulating material.

24. The apparatus of claim 1 wherein said cup comprises an electrically conductive material having an electrically insulating coating.

25. The apparatus of claim 1, wherein each of said plurality of contacts is torsionally bent so that an apex of a tip of each contact projects upward and a base of said tip points downward relative to a plane defined by said inner perimeter.

26. The apparatus of claim 1 further comprising a compressed gas line for supplying said pressurized gas to said first cavity.

27. The apparatus of claim 1 further comprising a bath containing an electroplating solution.

28. The apparatus of claim 27 wherein said electroplating solution comprises metal ions.

29. The apparatus of claim 28 wherein said electroplating solution comprises copper ions.

30. The apparatus of claim 27 further comprising an anode immersed in said electroplating solution.

31. The apparatus of claim 30 further comprising a power supply for biasing said anode positive and said electrical contacts negative.

32. The apparatus of claim 31 comprising a conductive path between said power supply and said electrical contacts, said conductive path comprising a slip ring and a brush.

33. The apparatus of claim 31 comprising a substrate to be electroplated, said compliant seal being in contact with a perimeter region of said substrate, said substrate being urged by said compliant seal against said cone.

34. The apparatus of claim 33 wherein contact between said compliant seal and said perimeter region of said substrate prevents said electroplating solution from entering said first cavity.

35. The apparatus of claim 33 wherein said substrate comprises a semiconductor wafer.