Using backgrind wafer tape to enable wafer mounting of bumped wafers

• US 20020166625A1
• Filed: 05/14/2001
• Published: 11/14/2002
• Est. Priority Date: 05/14/2001
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Sanchez, Jose L., Ball, Michael B.
• Granted Patent: US 6,949,158 B2
• Time in Patent Office: Days
• US Class Current: 156/247
• CPC Class Codes: B24B 21/04 for grinding plane surfaces
• CPC Class Codes: H01L 21/67132 Apparatus for placing on an insulating substrate, e.g. tape
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 21/6838 with gripping and holding devices using a vacuum; Bernoulli devices
• CPC Class Codes: H01L 2221/68386 Separation by peeling
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/11003 for holding or transferring the bump preform
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 24/11 Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01032 Germanium [Ge]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01047 Silver [Ag]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01082 Lead [Pb]
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: Y10S 156/941 Means for delaminating semiconductive product
• CPC Class Codes: Y10T 156/1179 : with poking during delaminating [e.g., jabbing, etc.]
• CPC Class Codes: Y10T 156/19 : Delaminating means

Abstract

A method and apparatus for mounting a wafer on a wafer mount and thinning the wafer on the wafer mount. The wafer includes a front surface having bumps located thereon and a back surface. Attached to the bumps on the wafer is an adhesive tape having a backing. The wafer mount includes a suction surface with apertures that communicate with a vacuum. The wafer is mounted on the suction surface with its front surface face down with the backing of the adhesive tape abutting the suction surface of the wafer mount. The wafer is then suctioned to the wafer mount by the vacuum communicating with the apertures in the suction surface, after which, the back surface of the wafer undergoes a grinding process to thin the wafer. Since the backing attached to the bumps on the wafer is substantially planar and sits substantially flat on the suction surface of the wafer mount, the force exerted on the wafer from the thinning process does not overcome the suction force holding the wafer on the wafer mount. Thus, the bumped wafer may be thinned without damaging the bumps and the active surface of the wafer.

Claims

1. A method of attaching a wafer having bumps on a surface thereof, comprising:

attaching a tape having an adhesive and a backing on at least a portion of said surface of said wafer;

providing a wafer mount having a suction surface; and

applying said suction force to said backing of said tape.

2. The method of claim 1, further comprising:

removing wafer material from a back surface of said wafer.

3. The method of claim 1, wherein said attaching a tape having an adhesive and a backing includes:

conforming said backing to include a substantially planar surface on at least a portion thereof.

4. The method of claim 3, wherein said applying said suction for to said backing of said tape comprises applying a suction force to said substantially planar surface of said suction surface.

5. The method of claim 1, wherein said applying a tape having an adhesive and a backing comprises:

conforming at least a portion of the adhesive of said tape to said bumps forming a substantially planar surface on said backing of said tape.

6. The method of claim 1, wherein said applying a suction force to said backing of said tape includes abutting said backing to said suction surface of said wafer mount.

7. The method of claim 1, wherein said wafer comprises a wafer having a thickness of at least about 12 mils.

8. The method of claim 2, wherein said removing comprises thinning said wafer to a thickness in the range of about 6 mils and about 12 mils.

9. The method of claim 2, wherein said removing comprises thinning said wafer to one of about 6 mils thickness and less than about 6 mils thickness.

10. The method of claim 2, wherein said removing comprises grinding said back surface of said wafer.

11. The method of claim 2, wherein said removing comprises thinning said wafer by chemical-mechanical polishing said back surface of said wafer.

13. The method of claim 12, further comprising:

removing wafer material from another surface of said wafer.

14. The method of claim 12, wherein said attaching said backing comprises:

conforming said backing to at least a portion of said surface of said wafer for forming a substantially planar surface.

15. The method of claim 14, wherein said holding backing to said suction surface of said wafer mount comprises applying a suction force to said substantially planar surface of said backing.

16. The method of claim 12, wherein said attaching said backing includes conforming said adhesive and said backing to said bumps for forming a substantially planar surface on said backing.

17. The method of claim 12, wherein said holding said backing to said suction surface of said wafer mount comprises abutting at least a portion of said backing to said suction surface of said wafer mount.

18. The method of claim 12, wherein said wafer comprises a wafer having a thickness of at least about 12 mils.

19. The method of claim 13, wherein said removing comprises thinning said wafer to a thickness in the range of about 6 mils and about 12 mils.

20. The method of claim 13, wherein said removing comprises thinning said wafer to one of a thickness of about 6 mils and a thickness of about less than 6 mils.

21. The method of claim 13, wherein said removing comprises grinding said back surface of said wafer.

22. The method of claim 13, wherein said removing comprises thinning said wafer by chemical-mechanical polishing said back surface of said wafer.

24. The method of claim 23, wherein said attaching said adhesive having said backing comprises conforming said backing to include a substantially planar surface.

25. The method of claim 24, wherein said attaching said backing to at least a portion of said suction surface of said wafer mount comprises applying said suction force to said substantially planar surface of said backing.

26. The method of claim 23, wherein said attaching said adhesive having said backing comprises providing an adhesive portion conforming to said bumps for said backing includes a substantially planar surface.

27. The method of claim 23, wherein said attaching said backing to at least a portion of said suction surface of said wafer mount comprises abutting at least a portion of said backing to at least a portion of said suction surface for said suction force attaches said wafer to said wafer mount.

28. The method of claim 23, wherein said wafer comprises a wafer having a thickness of at least about 12 mils.

29. The method of claim 24, wherein said removing comprises thinning said wafer thickness in the range of about 6 mils and about 12 mils.

30. The method of claim 23, wherein said removing comprises thinning said wafer to one of about 6 mils and less than about 6 mils.

31. The method of claim 23, wherein said removing comprises grinding said back surface of said wafer.

32. The method of claim 23, wherein said removing comprises thinning said wafer by chemical-mechanical polishing said back surface of said wafer.

12. A method of holding a wafer having bumps on at least a portion of a surface thereof, comprising:

applying an adhesive to a portion of said surface of said wafer;

attaching a backing to at least a portion of said adhesive;

providing a wafer mount having a suction surface; and

holding said backing to said suction surface of said wafer mount using a suction force.

23. A method for the thinning of a wafer comprising:

providing a wafer having bumps on at least a portion of a surface thereof;

attaching an adhesive having a backing to at least a portion of the surface of said wafer;

providing a wafer mount having a suction surface;

attaching said backing of said adhesive to at least a portion of said suction surface of said wafer mount using a suction force; and

removing wafer material from another surface of said wafer.

33. A method of fabricating a wafer having a front surface having bumps thereon and a back surface, comprising:

applying an adhesive having a backing on said bumps of said front surface of said wafer;

providing a wafer mount having a suction surface;

attaching at least a portion of said backing to at least a portion of said suction surface of said wafer mount chuck using a suction force; and

removing wafer material from said back surface of said wafer.

34. The method of claim 33, wherein said applying said adhesive having said backing comprises conforming said backing to include a substantially planar surface.

35. The method of claim 34, wherein said applying at least a portion of said backing to at least a portion of said suction surface of said wafer mount comprises applying said suction force to at least a portion of said substantially planar surface of said backing.

36. The method of claim 33, wherein said applying said adhesive having said backing comprises providing an adhesive portion conforming to said bumps for said backing including a substantially planar surface.

37. The method of claim 33, wherein said attaching said backing to said suction surface of said wafer mount comprises abutting at least a portion of said backing to said suction surface for said suction force to attach said wafer to said wafer mount.

38. The method of claim 33, wherein said wafer comprises a wafer having a thickness of at least about 12 mils.

39. The method of claim 33, wherein said removing comprises thinning said wafer to a thickness in the range of between about 6 mils and about 12 mils.

40. The method of claim 33, wherein said removing comprises thinning said wafer to a thickness of one of about 6 mils and less than about 6 mils.

41. The method of claim 33, wherein said removing comprises grinding said second surface of said wafer.

42. The method of claim 33, wherein said removing comprises thinning said wafer by chemical-mechanical polishing said second surface of said wafer.

43. The method of claim 33, further comprising:

removing said adhesive from said wafer.

44. The method of claim 43, further comprising:

singulating said wafer into at least one die.

46. The method of claim 45, wherein said applying said adhesive having a backing comprises conforming said backing to include a substantially planar surface.

47. The method of claim 46, wherein said mounting said wafer to the wafer mounting chuck comprises applying said suction force to at least a portion of said substantially planar surface.

48. The method of claim 45, wherein said applying said adhesive having said backing comprises conforming said adhesive portion to at least a portion of said bumps for said backing to include a substantially planar surface.

49. The method of claim 45, wherein said mounting said wafer to the wafer mounting chuck comprises abutting at least a portion of said backing to a suction surface of the wafer mounting chuck.

50. The method of claim 45, wherein said wafer comprises a wafer having thickness of at least about 12 mils.

45. A method of mounting a bumped wafer having bumps on at least a portion of a surface thereof to a wafer mounting chuck, comprising:

applying an adhesive having a backing to at least a portion of said bumps and at least a portion of said surface of said surface of said wafer; and

mounting said wafer to said wafer mounting chuck using a suction force communicated through the wafer mounting chuck.

51. A method using a vacuum to hold a bumped wafer having a front surface having bumps thereon and a back surface, comprising:

applying an adhesive having a backing to at least a portion of the front surface of said wafer covering at least one bump thereon; and

holding at least a portion of said front surface of said wafer using a vacuum applied through at least a portion of a surface of a wafer mount.

52. The method of claim 51, wherein said applying said adhesive having said backing includes conforming said backing to include a substantially planar surface of a portion of said backing.

53. The method of claim 52, wherein said holding comprises applying said vacuum to said substantially planar surface of said backing.

54. The method of claim 51, wherein said applying said adhesive having a backing over said at least one bump comprises providing an adhesive conforming to said at least one bump for said backing to form a substantially planar surface.

55. The method of claim 51, wherein said holding comprises abutting at least a portion of said backing to said surface of the wafer mount for said vacuum holds said wafer to the wafer mount.

56. The method of claim 51, wherein said wafer comprises a wafer having a thickness of at least about 12 mils.

58. The assembly of claim 57, further comprising:

a wafer mount having a vacuum surface thereon, said vacuum surface of said wafer mount for abutting said at least a portion of said backing of said adhesive tape, and said vacuum surface including apertures therein for communicating a vacuum therethrough.

59. The assembly of claim 57, wherein said backing of said tape includes a substantially planar surface for overlying said at least one bump.

60. The assembly of claim 59, wherein said substantially planar surface of said backing of said tape provides an area for the application of a vacuum to at least a portion of said front surface of said wafer.

61. The assembly of claim 57, wherein said backing includes a substantially planar surface overlying said at least one bump.

62. The assembly of claim 57, wherein said adhesive attaches said at least one bump.

63. The assembly of claim 57, wherein said adhesive conforms to said at least one bump for said backing of said tape to form a substantially planar surface on at least a portion thereof.

64. The assembly of claim 57, wherein said tape substantially overlays another bump.

65. The assembly of claim 57, wherein said wafer comprises a wafer having thickness of at least 12 mils.

66. The assembly of claim 57, wherein said at least one bump comprises a conductive bump for electrical connection.

68. The assembly of claim 67, wherein said backing includes a substantially planar surface overlying said at least one bump.

69. The assembly of claim 67, wherein said adhesive attaches to said at least one bump for forming a substantially planar surface.

70. The assembly of claim 67, wherein said adhesive conforms to said at least one bump for said backing including a substantially planar surface on a portion thereof.

71. The assembly of claim 67, wherein said tape substantially covers the front surface of said wafer.

72. The assembly of claim 67, wherein said at least one bump comprises a conductive bump for electrical connection.

73. The assembly of claim 67, wherein said backing comprises a resilient material.

74. The assembly of claim 67, wherein said wafer comprises a thickness of at least 12 mils prior to being mounted to the wafer mount.

75. The assembly of claim 67, wherein said wafer comprises another thickness of one of about less than 6 mils and greater than about 6 mils and less than about 12 mils after grinding said back surface of said wafer.

57. A wafer mount assembly for a wafer having a front surface having at least one bump thereon and a back surface, comprising:

an adhesive tape having an adhesive and having a backing, said adhesive tape for adhesively attaching a portion of said front surface of said wafer having said at least one bump thereon to a portion of said wafer mount assembly.

67. An assembly of a bumped wafer mounted to a wafer mount for grinding, the bumped wafer comprising:

a wafer having a front surface and a back surface thereof, said front surface having at least one bump thereon; and

a tape having an adhesive and having a backing, said tape for adhesively attaching a portion of said wafer having said at least one bump thereon.