Method and device for protecting micro electromechanical systems structures during dicing of a wafer

• US 6,946,326 B2
• Filed: 12/05/2001
• Issued: 09/20/2005
• Est. Priority Date: 12/05/2000
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Harney, Kieran P., Spooner, Timothy R., Martin, John R., Courage, David S.
• Primary Examiner(s): Tran, Minhloan
• Assistant Examiner(s): Dickey, Thomas L
• Application Number:
  US10/006,964
• Publication Number:
  US 20020096743A1
• Time in Patent Office: 1,385 Days
• Field of Search: 257/414, 257/415, 257/417, 257/418, 257/620, 257/626, 257/678, 257/797, 438/68, 438/110, 438/113, 438/118, 438/458, 438/460, 438/464
• US Class Current: 438/113
• CPC Class Codes: B81C 1/00888 Multistep processes involving only mechanical separation, e.g. grooving followed by cleaving
• CPC Class Codes: B81C 1/00896 Temporary protection during separation into individual elements
• CPC Class Codes: H01L 21/6836 Wafer tapes, e.g. grinding or dicing support tapes adhesive tapes in general C09J7/20
• CPC Class Codes: H01L 2221/68327 used during dicing or grinding

Abstract

A wafer cap protects micro electromechanical system (“MEMS”) structures during a dicing of a MEMS wafer to produce individual MEMS dies. A MEMS wafer is prepared having a plurality of MEMS structure sites thereon. Upon the MEMS wafer, the wafer cap is mounted to produce a laminated MEMS wafer. The wafer cap is recessed in areas corresponding to locations of the MEMS structure sites on the MEMS wafer. The capped MEMS wafer can be diced into a plurality of MEMS dies without causing damage to or contaminating the MEMS die.

Claims

1. A method for making a protected MEMS structure, comprising:

(a) preparing a MEMS wafer having a plurality of MEMS structure sites thereon;

(b) mounting, upon the MEMS wafer, a spacer layer having a thickness to prevent electrostatically induced damage to the MEMS wafer and being perforated in areas corresponding to locations of the MEMS structure sites on the MEMS wafer, the spacer layer comprising a tape having adhesive on two sides and a flexible film; and

(c) mounting, upon the spacer layer, a wafer cap to produce a laminated MEMS wafer.

2. The method as claimed in claim 1, wherein the flexible film is transmissive to UV radiation.

3. The method as claimed in claim 2, wherein the wafer cap is a cover tape.

6. The method as claimed in claim 1, wherein the wafer cap is a cover tape.

9. The method as claimed in claim 1, wherein the flexible film is about 40 mils thick.

10. The method as claimed in claim 1, wherein the flexible film and tape are combined and then cut to produce areas corresponding to the MEMS structures on the MEMS wafer.

11. The method as claimed in claim 10, wherein the flexible film and tape are combined using pressure to promote adhesion.

12. The method as claimed in claim 1, wherein the flexible film and tape are combined and then cut by a laser to produce areas corresponding to the MEMS structures on the MEMS wafer.

13. The method as claimed in claim 1, wherein the flexible film and tape are combined and then punched to produce areas corresponding to the MEMS structures on the MEMS wafer.

14. The method as claimed in claim 1, wherein the flexible film and tape are pre-cut to produce areas corresponding to the MEMS structures on the MEMS wafer before being combined.

15. The method as claimed in claim 1, wherein the flexible film and tape are pre-punched to produce areas corresponding to the MEMS structures on the MEMS wafer before being combined.

4. The method as claimed in 3, wherein the spacer layer has a thickness to prevents the wafer cap from deflecting in such a manner to damage the MEMS structures.

5. The method as claimed in 2, wherein the spacer layer has a thickness to prevents the wafer cap from deflecting in such a manner to damage the MEMS structures.

7. The method as claimed in 6, wherein the spacer layer has a thickness to prevents the wafer cap from deflecting in such a manner to damage the MEMS structures.

8. The method as claimed in 1, wherein the spacer layer has a thickness to prevents the wafer cap from deflecting in such a manner to damage the MEMS structures.

16. A method for making a protected MEMS structure, comprising:

(a) preparing a MEMS wafer having a plurality of MEMS structure sites thereon;

(b) mounting, upon the MEMS wafer, a spacer layer having a thickness to prevent a wafer cap from coming into physical contact with the MEMS wafer and being perforated in areas corresponding to locations of the MEMS structure sites on the MEMS wafer, the spacer layer comprising a tape having adhesive on two sides and a flexible film; and

(c) mounting, upon the spacer layer, a wafer cap to produce a laminated MEMS wafer.

17. The method as claimed in claim 16, wherein the flexible film is transmissive to UV radiation.

18. The method as claimed in claim 17, wherein the wafer cap is a cover tape.

19. The method as claimed in claim 16, wherein the flexible film comprises a static dissipative material.

20. The method as claimed in claim 16, wherein the wafer cap is a cover tape.

21. The method as claimed in claim 16, wherein the flexible film is about 40 mils thick.

22. The method as claimed in claim 16, wherein the spacer layer comprises a plurality of layers of perforated tape, an aggregate of the plurality of layers of perforated tape producing a thickness to prevent the wafer cap from coming into physical contact with the MEMS wafer.

23. The method as claimed in claim 16, wherein the flexible film and tape are combined and then cut to produce areas corresponding to the MEMS structures on the MEMS wafer.

24. The method as claimed in claim 23, wherein the flexible film and tape are pre-punched to produce areas corresponding to the MEMS structures on the MEMS wafer before being combined.

25. The method as claimed in claim 16, wherein the flexible film and tape are combined and then cut by a laser to produce areas corresponding to the MEMS structures on the MEMS wafer.

26. The method as claimed in claim 16, wherein the flexible film and tape are combined and then punched to produce areas corresponding to the MEMS structures on the MEMS wafer.

27. The method as claimed in claim 16, wherein the flexible film and tape are pre-cut to produce areas corresponding to the MEMS structures on the MEMS wafer before being combined.

28. The method as claimed in claim 16, wherein the flexible film and tape are combined using pressure to promote adhesion.

29. The method as claimed in claim 16, wherein the wafer cap comprises a static dissipative material.

30. The method as claimed in claim 16, wherein the spacer layer comprises a static dissipative material.

31. A method for making a protected MEMS structure, comprising:

(a) preparing a MEMS wafer having a plurality of MEMS structure sites thereon;

(b) mounting, upon the MEMS wafer, a spacer layer having a thickness to prevent electrostatically induced damage to the MEMS wafer and to prevent a wafer cap from coming into physical contact with the MEMS wafer and being perforated in areas corresponding to locations of the MEMS structure sites on the MEMS wafer, the spacer layer comprising a tape having adhesive on two sides and a flexible film; and

(c) mounting, upon the spacer layer, a wafer cap to produce a laminated MEMS wafer.

32. The method as claimed in claim 31, wherein the flexible film is transmissive to UV radiation.

33. The method as claimed in claim 32, wherein the wafer cap is a cover tape.

34. The method as claimed in claim 31, wherein the wafer cap is a cover tape.

35. The method as claimed in claim 31, wherein the flexible film is about 40 mils thick.

36. The method as claimed in claim 31, wherein the flexible film and tape are combined and then cut to produce areas corresponding to the MEMS structures on the MEMS wafer.

37. The method as claimed in claim 36, wherein the flexible film and tape are combined using pressure to promote adhesion.

38. The method as claimed in claim 31, wherein the flexible film and tape are combined and then cut by a laser to produce areas corresponding to the MEMS structures on the MEMS wafer.

39. The method as claimed in claim 31, wherein the flexible film and tape are combined and then punched to produce areas corresponding to the MEMS structures on the MEMS wafer.

40. The method as claimed in claim 31, wherein the flexible film and tape are pre-cut to produce areas corresponding to the MEMS structures on the MEMS wafer before being combined.

41. The method as claimed in claim 31, wherein the flexible film and tape are pre-punched to produce areas corresponding to the MEMS structures on the MEMS wafer before being combined.

42. A laminated MEMS wafer, comprising:

a MEMS wafer having a plurality of MEMS structure sites located thereon;

a spacer layer mounted upon the MEMS wafer, the spacer layer being perforated in areas corresponding to locations of the MEMS structure sites on the MEMS wafer; and

a wafer cap mounted upon said spacer layer to produce a laminated MEMS wafer;

said spacer layer having a thickness to prevent electrostatically induced damage to said MEMS wafer;

said spacer layer comprising a tape having adhesive on two sides and a flexible film.

43. The laminated MEMS wafer as claimed in claim 42, wherein said flexible film is transmissive to UV radiation.

44. The laminated MEMS wafer as claimed in claim 42, wherein said flexible film is about 40 mils thick.

45. The laminated MEMS wafer as claimed in claim 42, wherein said flexible film and tape are combined and then cut to produce areas corresponding to the MEMS structures on said MEMS wafer.

46. The laminated MEMS wafer as claimed in claim 45, wherein said flexible film and tape are combined using pressure to promote adhesion.

47. The laminated MEMS wafer as claimed in claim 42, wherein said flexible film and tape are combined and then punched to produce areas corresponding to the MEMS structures on said MEMS wafer.

48. The laminated MEMS wafer as claimed in claim 42, wherein said flexible film and tape are pre-cut to produce areas corresponding to the MEMS structures on said MEMS wafer before being combined.

49. The laminated MEMS wafer as claimed in claim 42, wherein said flexible film and tape are pre-punched to produce areas corresponding to the MEMS structures on said MEMS wafer before being combined.

50. A laminated MEMS, comprising:

a MEMS wafer having a plurality of MEMS structure sites located thereon;

a spacer layer mounted upon the MEMS wafer, the spacer layer being perforated in areas corresponding to locations of the MEMS structure sites on the MEMS wafer; and

a wafer cap mounted upon said spacer layer to produce a laminated MEMS wafer;

said spacer layer having a thickness to prevent damage to the MEMS structures due to said wafer cap coming into physical contact with said MEMS wafer;

said spacer layer comprising a tape having adhesive on two sides and a flexible film.

51. The laminated MEMS wafer as claimed in claim 50, wherein said flexible film is transmissive to UV radiation.

52. The laminated MEMS wafer as claimed in claim 50, wherein said flexible film is about 40 mils thick.

53. The laminated MEMS wafer as claimed in claim 50, wherein said spacer layer comprises a plurality of layers of perforated tape, an aggregate of the plurality of layers of perforated tape producing a thickness to prevent damage to the MEMS structures due to said wafer cap coming into physical contact with said MEMS wafer.

54. The laminated MEMS wafer as claimed in claim 50, wherein said flexible film and tape are combined and then cut to produce areas corresponding to the MEMS structures on said MEMS wafer.

55. The laminated MEMS wafer as claimed in claim 54, wherein said flexible film and tape are combined using pressure to promote adhesion.

56. The laminated MEMS wafer as claimed in claim 50, wherein said flexible film and tape are combined and then punched to produce areas corresponding to the MEMS structures on said MEMS wafer.

57. The laminated MEMS wafer as claimed in claim 50, wherein said flexible film and tape are pre-cut to produce areas corresponding to the MEMS structures on said MEMS wafer before being combined.

58. The laminated MEMS wafer as claimed in claim 50, wherein said flexible film and tape are pre-punched to produce areas corresponding to the MEMS structures on said MEMS wafer before being combined.

59. The laminated MEMS wafer as claimed in claim 50, wherein the wafer cap comprises a static dissipative material.

60. The laminated MEMS wafer as claimed in claim 50, wherein the spacer layer comprises a static dissipative material.

61. The laminated MEMS wafer as claimed in claim 50, further comprising:

a contiguous tape applied to a backside of said MEMS wafer, the backside of said MEMS wafer being a side opposite of a side having said wafer cap located thereon.

62. The laminated MEMS wafer as claimed in claim 61, wherein said contiguous tape is applied to the backside of said MEMS wafer after the laminated MEMS wafer is sawn.

63. A laminated MEMS wafer, comprising:

a MEMS wafer having a plurality of MEMS structure sites located thereon;

a spacer layer mounted upon the MEMS wafer, the spacer layer being perforated in areas corresponding to locations of the MEMS structure sites on the MEMS wafer; and

a wafer cap mounted upon said spacer layer to produce a laminated MEMS wafer

said spacer layer having a thickness to prevent said wafer cap from coming into physical contact with said MEMS wafer and to prevent electrostatically induced damage to said MEMS wafer;

said spacer layer comprising a tape having adhesive on two sides and a flexible film.

64. The laminated MEMS wafer as claimed in claim 63, wherein said flexible film is transmissive to UV radiation.

65. The laminated MEMS wafer as claimed in claim 63, wherein said flexible film is about 40 mils thick.

66. The laminated MEMS wafer as claimed in claim 63, wherein said flexible film and tape are combined and then cut to produce areas corresponding to the MEMS structures on said MEMS wafer.

67. The laminated MEMS wafer as claimed in claim 66, wherein said flexible film and tape are combined using pressure to promote adhesion.

68. The laminated MEMS wafer as claimed in claim 63, wherein said flexible film and tape are combined and then punched to produce areas corresponding to the MEMS structures on said MEMS wafer.

69. The laminated MEMS wafer as claimed in claim 63, wherein said flexible film and tape are pre-cut to produce areas corresponding to the MEMS structures on said MEMS wafer before being combined.

70. The laminated MEMS wafer as claimed in claim 63, wherein said flexible film and tape are pre-punched to produce areas corresponding to the MEMS structures on said MEMS wafer before being combined.