Methods and apparatuses for removing material from discrete areas on a semiconductor wafer

• US 6,153,532 A
• Filed: 02/27/1998
• Issued: 11/28/2000
• Est. Priority Date: 02/27/1998
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Lane, Richard H., Dow, Daniel B.
• Primary Examiner(s): Utech, Benjamin L.
• Assistant Examiner(s): DEO, DUY VU NGUYEN
• Application Number:
  US09/032,212
• Time in Patent Office: 1,005 Days
• Field of Search: 438/745, 438/748, 438/754, 438/975, 156/345, 118/669, 118/624, 216/90, 216/91, 216/92
• US Class Current: 438/745
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/67075 for wet etching

Abstract

Methods and apparatuses for removing material from discrete areas on a semiconductor wafer are described. In one implementation, an etchant applicator is provided having a tip portion. Liquid etchant material is suspended proximate the tip portion and the etchant applicator is moved, together with the suspended liquid, sufficiently close to a discrete area on a wafer to transfer liquid etchant onto the discrete area. In various embodiments the tip portion can comprise fluid permeable materials, fluid-absorbent materials, and/or wick assemblies. An exhaust outlet can be provided operably proximate the tip portion for removing material from over the wafer. The tip portion can be moved to touch the discrete area.

Claims

1. A method of removing material from discrete areas on a wafer during processing comprising:

suspending a liquid etchant material proximate a tip portion of an etchant applicator;

moving the etchant applicator and suspended liquid sufficiently close to a discrete area on a wafer to transfer at least some suspended liquid etchant material onto the discrete area; and

retaining the liquid etchant material within the discrete area without using a physical barrier as part of the etchant applicator.

2. The method of claim 1, wherein the tip portion comprises a fluid permeable material.

3. The method of claim 1, wherein the tip portion comprises a fluid permeable material having a plurality of fibrous members.

4. The method of claim 1, wherein the tip portion comprises a fluid permeable material and the suspending comprises absorbing liquid etchant onto the material.

5. The method of claim 1, wherein the tip portion comprises a fluid permeable material and the suspending comprises absorbing liquid etchant through the material.

6. The method of claim 1, wherein the tip portion comprises a hollow opening and the suspending comprises projecting a droplet portion of the liquid etchant material outward of the hollow opening.

7. The method of claim 1, wherein the moving of the etchant applicator comprises touching the discrete area with the tip portion.

8. A method of removing material from discrete areas on a wafer during processing comprising:

providing an etchant applicator having a tip portion;

providing an amount of etchant material over the tip portion, the etchant material being supported by the tip portion;

placing the tip portion into proximity with a discrete area of a wafer sufficiently to bring at least some of the supported etchant material into physical contact with the discrete area;

removing the tip portion from the wafer, at least some of the supported etchant material being left behind thereon; and

retaining any liquid portion of the etchant material within the discrete area without using a physical barrier as part of the etchant applicator.

9. The method of claim 8, wherein the tip portion comprises a fluid-absorbent material.

10. The method of claim 8, wherein:

the tip portion comprises a fluid-absorbent material;

the providing of the amount of etchant material comprises absorbing the amount of etchant material onto the tip portion; and

the placing of the tip portion comprises touching the discrete area with at least some of the fluid-absorbent material.

11. The method of claim 8, wherein the tip portion comprises a wick assembly.

12. The method of claim 8, wherein the tip portion comprises a wick assembly having a plurality of fibers.

13. The method of claim 8, wherein the providing of the amount of etchant material comprises immersing the tip portion in an amount of the etchant material prior to the placing.

14. A method of removing material from discrete areas on a wafer during processing comprising:

clinging a liquid etchant material onto an applicator tip portion;

moving the applicator tip portion and clung liquid etchant to sufficiently proximate a discrete area on a wafer to cause removal of clung liquid etchant material from the tip portion and onto the discrete area; and

retaining the liquid etchant material within the discrete area without using a physical barrier as part of the applicator tip portion.

15. The method of claim 14, wherein the applicator tip portion comprises a hollow opening and the clinging comprises projecting a droplet portion of the liquid etchant material outward of the hollow opening.

16. The method of claim 14, wherein the applicator tip portion comprises a fluid-absorbent material and the clinging comprises absorbing the liquid etchant material onto the fluid-absorbent material.

17. The method of claim 14, wherein the applicator tip portion comprises a fluid-permeable material, and the clinging comprises providing the liquid etchant material into the fluid-permeable material.

18. The method of claim 14, wherein the moving comprises touching the discrete area with the applicator tip portion.

19. The method of claim 14, wherein the moving comprises touching the discrete area only with etchant material and not any of the tip portion.

20. A method of removing material from discrete areas on a wafer during processing comprising:

providing a liquid etchant applicator having a fluid-permeable tip portion;

providing liquid etchant material over the fluid-permeable tip portion;

moving the fluid-permeable tip portion into contact with a discrete area of a wafer;

removing the fluid-permeable tip portion from the wafer, at least some of the liquid etchant material being left behind thereon; and

retaining the liquid etchant material within the discrete area without using a physical barrier as part of the etchant applicator.

21. The method of claim 20, wherein the providing of the liquid etchant material over the fluid-permeable tip portion comprises dipping the tip portion in an amount of liquid etchant material.

22. The method of claim 20, wherein the fluid-permeable tip portion comprises fibrous material.

23. The method of claim 20, wherein the fluid permeable tip portion comprises a fluid-absorbent material.

24. The method of claim 20, wherein the fluid permeable tip portion comprises a fluid-absorbent material, and the providing of the liquid etchant material over the fluid-permeable tip portion comprises absorbing liquid etchant material within the tip portion.

25. A method of removing material from discrete areas on a wafer during processing comprising:

providing a liquid etchant applicator having a wick assembly thereon configured for receiving an amount of liquid etchant;

supporting an amount of liquid etchant with said wick assembly;

transferring at least some of the liquid etchant from said wick assembly onto a discrete area on a wafer; and

retaining the liquid etchant within the discrete area without using a physical barrier as part of the etchant applicator.

26. The method of claim 25, wherein the wick assembly comprises a fluid-absorbent material.

27. The method of claim 25, wherein the wick assembly comprises a plurality of fibrous members.

28. The method of claim 25, wherein said supporting comprises dipping a portion of said wick assembly into liquid etchant.

29. The method of claim 25, wherein said transferring comprises touching said discrete area with the wick assembly.

30. The method of claim 25, wherein said transferring comprises touching said discrete area with liquid etchant supported by the wick assembly.

31. A method of removing material from discrete areas on a wafer during processing comprising:

providing a liquid etchant applicator assembly comprising a fluid-permeable tip portion and an exhaust outlet proximate the tip portion, the exhaust outlet being configured to remove material from around the tip portion;

providing the fluid-permeable tip portion with liquid etchant material;

moving the fluid-permeable tip portion into contact with a discrete area of a wafer;

transferring at least some of the liquid etchant material from the fluid-permeable tip portion onto the wafer;

retaining the liquid etchant material within the discrete area without reliance on any part of the etchant applicator as a physical barrier; and

removing material from over the discrete area through the exhaust outlet.

32. The method of claim 31, wherein the exhaust outlet comprises a vacuum device configured to remove gaseous material.

33. The method of claim 31, wherein the exhaust outlet comprises a sheath and the removing comprises touching the wafer with the sheath.

34. The method of claim 31, wherein the fluid-permeable tip portion comprises a plurality of fibrous members.

35. The method of claim 31, wherein the providing of the fluid-permeable tip portion with liquid etchant material comprises providing a reservoir of etchant material in fluid communication with the tip portion.

36. A method of removing material from discrete areas on a wafer during processing comprising:

providing a liquid etchant applicator comprising a fluid-absorbent tip portion;

providing a liquid etchant reservoir in fluid communication with the fluid-absorbent tip portion;

absorbing liquid etchant from the reservoir onto the fluid-absorbent tip portion;

contacting a discrete area on a wafer with the fluid-absorbent tip portion, the contacting transferring some of the liquid etchant onto the discrete area; and

retaining the liquid etchant within the discrete area without using a physical barrier as part of the etchant applicator.

37. The method of claim 36, wherein fluid-absorbent tip portion comprises a fibrous wick.

38. The method of claim 36, wherein the liquid etchant comprises hydrofluoric acid.

39. A method of removing material from discrete areas on a wafer during processing comprising:

providing a liquid etchant applicator having a fluid-permeable tip portion;

dipping at least some of the tip portion into an amount of liquid etchant material;

transferring at least some liquid etchant from the dipped tip portion onto a discrete area on a wafer; and

retaining the liquid etchant material within the discrete area without using a physical barrier as part of the etchant applicator.

40. The method of claim 39, wherein the transferring comprises dabbing the discrete area with the tip portion, the dabbing placing the tip portion into physical contact with the discrete area for no more than two seconds.

41. The method of claim 39, wherein the transferring comprises dabbing the discrete area with the tip portion, the dabbing placing the tip portion into physical contact with the discrete area for no more than one second.

42. A method of removing material from over alignment marks on a wafer during processing comprising:

providing a substrate having a plurality of alignment marks thereover;

processing the substrate and depositing material over the alignment marks;

providing a liquid etchant applicator having a fluid-permeable tip portion;

providing liquid etchant material over the fluid-permeable tip portion;

moving the liquid etchant applicator into proximity with the alignment marks;

transferring at least some of the liquid etchant material from the fluid-permeable tip portion onto the material over the alignment marks; and

retaining the liquid etchant material where transferred without using a physical barrier as part of the etchant applicator.

43. The method of claim 42, wherein the transferring comprises touching the wafer with the tip portion.

44. The method of claim 42, wherein the fluid-permeable tip portion comprises a plurality of fibers.

45. The method of claim 42, wherein the fluid-permeable tip portion comprises an absorbent material.

46. The method of claim 42, wherein the fluid-permeable tip portion comprises a wick assembly.

47. A method of removing material from discrete areas on a wafer during processing comprising:

providing a liquid etchant applicator having a fluid-permeable tip portion;

providing liquid etchant material over the fluid-permeable tip portion;

dabbing a discrete area on a wafer with the tip portion sufficiently to transfer liquid etchant material onto the discrete area; and

retaining the liquid etchant material within the discrete area without using a physical barrier as part of the etchant applicator.

48. The method of claim 47, wherein the dabbing comprises touching the discrete area with the tip portion for no longer than about two seconds.

49. The method of claim 47, wherein the dabbing comprises repeatedly touching the discrete area with the tip portion, at least one of the touchings comprising touching the discrete area for no longer than about two seconds.

50. A method of removing material from discrete areas on a wafer during processing comprising:

providing a liquid etchant applicator having a fluid-permeable tip portion;

providing liquid etchant material over the fluid-permeable tip portion;

touching a discrete area on a wafer with the tip portion sufficiently to transfer liquid etchant material onto the discrete area;

while the tip portion is touching the wafer, moving the tip portion across a surface of the wafer; and

retaining the liquid etchant material within the discrete area without using a physical barrier as part of the etchant applicator.