WIRE BONDING METHOD FOR PREVENTING POLYMER CRACKING

Abstract

This invention provides a wire bonding method, comprising providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer; forming a polymer layer on the passivation layer; forming an adhesive/barrier layer on the polymer layer; forming a metal pad layer on the adhesive/barrier layer; bonding a wire onto the metal pad layer to form a ball bond thereon; and after forming the ball bond on the metal pad layer, running the wire so as to contact the wire with a second bonding pad and forming a wedge bond thereto.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:

FIG. 1 is a schematic, cross-sectional diagram illustrating the ball-wedge wire bonding with ball bonding on thick polymer layer in accordance with one preferred embodiment of this invention;

FIG. 2 is a schematic, cross-sectional diagram illustrating the ball-wedge wire bonding with ball bonding on thick adhesive/barrier layer in accordance with another preferred embodiment of this invention;

FIG. 3 is a schematic, cross-sectional diagram illustrating the ball-wedge wire bonding with ball bonding on thick gold pad in accordance with the third preferred embodiment of this invention;

FIG. 4 is a schematic, cross-sectional diagram illustrating the ball-wedge wire bonding with ball bonding on hard metal pad in accordance with the fourth preferred embodiment of this invention;

FIG. 5 is a schematic, cross-sectional diagram illustrating the ball-wedge wire bonding with ball bonding on hard metal pad in accordance with the fourth preferred embodiment of this invention; and

FIGS. 6-12 are schematic, cross-sectional diagrams illustrating the exemplary process of forming the thick polymer layer on passivation of the IC die 10 as set forth in FIGS. 1-5.

Claims

1. A wire bonding method, comprising: providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer;forming a polymer layer on the passivation layer;forming an adhesive/barrier layer on the polymer layer;forming a metal pad layer on the adhesive/barrier layer;bonding a wire onto the metal pad layer to form a ball bond thereon; andafter forming the ball bond on the metal pad layer, running the wire so as to contact the wire with a second bonding pad and forming a wedge bond thereto.

2. The wire bonding method according to claim 1 wherein the second bonding pad is provided on the IC die, another die, ceramic substrate, organic substrate, silicon substrate, glass substrate, leadframe or a flexible substrate with only polymer layer.

3. The wire bonding method according to claim 1 wherein the passivation layer comprises silicon nitride, silicon oxide, silicon oxy-nitride and combinations thereof.

4. The wire bonding method according to claim 1 wherein the first bonding pads comprise sputtered aluminum pads, CVD aluminum pads, electroplated copper pads, and CVD copper pads.

5. The wire bonding method according to claim 1 wherein the polymer layer comprises polyimide (PI) and benzocyclobutene (BCB).

6. The wire bonding method according to claim 1 wherein the polymer layer has a thickness that is greater than 3 micrometers.

7. The wire bonding method according to claim 1 wherein the polymer layer has a thickness of 3-100 micrometers.

8. The wire bonding method according to claim 1 wherein the polymer layer has a thickness of 8-30 micrometers.

9. The wire bonding method according to claim 1 wherein the adhesive/barrier layer comprises TiW, Ti, Ta, TaN, Cr, CrCu and TiN.

10. The wire bonding method according to claim 1 wherein the adhesive/barrier layer has a thickness of about 1000 angstroms to 6000 angstroms.

11. The wire bonding method according to claim 1 wherein the adhesive/barrier layer has a thickness of about 1000 angstroms to 6000 angstroms.

12. The wire bonding method according to claim 1 wherein the adhesive/barrier layer has a thickness of about 1500 angstroms to 4500 angstroms.

13. The wire bonding method according to claim 1 wherein the metal pad layer comprises Au, Ru, Rh, Pt and Ag.

14. The wire bonding method according to claim 1 wherein the wire comprises Au, Cu and Al.

15. A wire bonding method, comprising: providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer;forming a polymer layer on the passivation layer;forming a Cr layer on the polymer layer;forming a Cu layer on the Cr layer;forming a Ni layer on the Cu layer;forming a Au layer on the Ni layer;bonding a wire onto the Au layer to form a ball bond thereon; andafter forming the ball bond on the Au layer, running the wire so as to contact the wire with a second bonding pad and forming a wedge bond thereto.

16. The wire bonding method according to claim 15 wherein the second bonding pad is provided on the IC die, another die, ceramic substrate, organic substrate, silicon substrate, glass substrate, leadframe or a flexible substrate with only polymer layer.

17. The wire bonding method according to claim 15 wherein the passivation layer comprises silicon nitride, silicon oxide, silicon oxy-nitride and combinations thereof.

18. The wire bonding method according to claim 15 wherein the first bonding pads comprise sputtered aluminum pads, CVD aluminum pads, electroplated copper pads, and CVD copper pads.

19. The wire bonding method according to claim 15 wherein the polymer layer comprises polyimide (PI) and benzocyclobutene (BCB).

20. The wire bonding method according to claim 15 wherein the polymer layer has a thickness that is greater than 3 micrometers.

21. The wire bonding method according to claim 15 wherein the polymer layer has a thickness of 3-100 micrometers.

22. The wire bonding method according to claim 15 wherein the polymer layer has a thickness of 8-30 micrometers.

23. The wire bonding method according to claim 15 wherein the Cr layer has a thickness of about 100 angstroms to 2000 angstroms.

24. The wire bonding method according to claim 15 wherein the Cu layer has a thickness of about 1 micrometer to 10 micrometers.

25. The wire bonding method according to claim 15 wherein the Ni layer has a thickness of about 0.5 micrometer to 5 micrometers.

26. The wire bonding method according to claim 15 wherein the Au layer has a thickness of about 300 angstroms to 10000 angstroms.

27. The wire bonding method according to claim 15 wherein the wire comprises Au, Cu and Al.

28. A wire bonding method, comprising: providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer;forming a polymer layer on the passivation layer;forming an adhesive/barrier layer on the polymer layer;forming a metal pad layer on the adhesive/barrier layer;bonding a wire onto the metal pad layer to form a wedge bond thereon; andafter forming the ball bond on the metal pad layer, running the wire so as to contact the wire with a second bonding pad and forming a ball bond thereto.

29. The wire bonding method according to claim 28 wherein the second bonding pad is provided on the IC die, another die, ceramic substrate, organic substrate, silicon substrate, glass substrate, leadframe or a flexible substrate with only polymer layer.

30. The wire bonding method according to claim 28 wherein the passivation layer comprises silicon nitride, silicon oxide, silicon oxy-nitride and combinations thereof.

31. The wire bonding method according to claim 28 wherein the first bonding pads comprise sputtered aluminum pads, CVD aluminum pads, electroplated copper pads, and CVD copper pads.

32. The wire bonding method according to claim 28 wherein the polymer layer comprises polyimide (PI) and benzocyclobutene (BCB).

33. The wire bonding method according to claim 28 wherein the polymer layer has a thickness that is greater than 3 micrometers.

34. The wire bonding method according to claim 28 wherein the polymer layer has a thickness of 3-100 micrometers.

35. The wire bonding method according to claim 28 wherein the polymer layer has a thickness of 8-30 micrometers.

36. The wire bonding method according to claim 28 wherein the adhesive/barrier layer comprises TiW, Ti, Ta, TaN, Cr, CrCu and TiN.

37. The wire bonding method according to claim 28 wherein the adhesive/barrier layer has a thickness of about 1000 angstroms to 6000 angstroms.

38. The wire bonding method according to claim 28 wherein the adhesive/barrier layer has a thickness of about 1000 angstroms to 6000 angstroms.

39. The wire bonding method according to claim 28 wherein the adhesive/barrier layer has a thickness of about 1500 angstroms to 4500 angstroms.

40. The wire bonding method according to claim 28 wherein the metal pad layer comprises Au, Ru, Rh, Pt and Ag.

41. The wire bonding method according to claim 28 wherein the wire comprises Au, Cu and Al.

42. A wire bonding method, comprising: providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer;forming a polymer layer on the passivation layer;forming a Cr layer on the polymer layer;forming a Cu layer on the Cr layer;forming a Ni layer on the Cu layer;forming a Au layer on the Ni layer;bonding a wire onto the Au layer to form a wedge bond thereon; andafter forming the ball bond on the Au layer, running the wire so as to contact the wire with a second bonding pad and forming a ball bond thereto.

43. The wire bonding method according to claim 42 wherein the second bonding pad is provided on the IC die, another die, ceramic substrate, organic substrate, silicon substrate, glass substrate, leadframe or a flexible substrate with only polymer layer.

44. The wire bonding method according to claim 42 wherein the passivation layer comprises silicon nitride, silicon oxide, silicon oxy-nitride and combinations thereof.

45. The wire bonding method according to claim 42 wherein the first bonding pads comprise sputtered aluminum pads, CVD aluminum pads, electroplated copper pads, and CVD copper pads.

46. The wire bonding method according to claim 42 wherein the polymer layer comprises polyimide (PI) and benzocyclobutene (BCB).

47. The wire bonding method according to claim 42 wherein the polymer layer has a thickness that is greater than 3 micrometers.

48. The wire bonding method according to claim 42 wherein the polymer layer has a thickness of 3-100 micrometers.

49. The wire bonding method according to claim 42 wherein the polymer layer has a thickness of 8-30 micrometers.

50. The wire bonding method according to claim 42 wherein the Cr layer has a thickness of about 100 angstroms to 2000 angstroms.

51. The wire bonding method according to claim 42 wherein the Cu layer has a thickness of about 1 micrometer to 10 micrometers.

52. The wire bonding method according to claim 42 wherein the Ni layer has a thickness of about 0.5 micrometer to 5 micrometers.

53. The wire bonding method according to claim 42 wherein the Au layer has a thickness of about 5000 angstroms to 10000 angstroms.

54. The wire bonding method according to claim 42 wherein the wire comprises Au, Cu and Al.

55. A wire bonding method, comprising: providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer;forming a polymer layer on the passivation layer;forming an adhesive/barrier layer on the polymer layer;forming a metal pad layer on the adhesive/barrier layer; andbonding a wire onto the metal pad layer at a bonding force ranging between 200 mg and 500 mg and a bonding temperature that is less than glass transition point of the polymer layer to form a ball bond thereon.

56. The wire bonding method according to claim 55 wherein the passivation layer comprises silicon nitride, silicon oxide, silicon oxy-nitride and combinations thereof.

57. The wire bonding method according to claim 55 wherein the polymer layer comprises polyimide (PI) or benzocyclobutene (BCB).

58. The wire bonding method according to claim 55 wherein the polymer layer has a thickness that is in the range between 3 and 30 micrometers.

59. The wire bonding method according to claim 55 wherein the adhesive/barrier layer comprises TiW, or Ti, or Cr, or TiN.

60. The wire bonding method according to claim 55 wherein the adhesive/barrier layer has a thickness of about 1500 angstroms to 4500 angstroms.

61. The wire bonding method according to claim 55 wherein the metal pad layer comprises Au, Ru, Rh, Pt and Ag.

62. A method for preventing polymer cracking during wire bonding, comprising: providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer;forming a polymer layer on the passivation layer;forming an adhesive/barrier layer on the polymer layer;forming a gold layer having a thickness of greater than 8 micrometers on the adhesive/barrier layer; andbonding a wire onto the gold layer to form a wire bond thereon.

63. The wire bonding method according to claim 62 wherein the adhesive/barrier layer comprises TiW.

64. The wire bonding method according to claim 62 wherein the adhesive/barrier layer has a thickness in the range between 0.5 and 1 micrometers.

65. A method for preventing polymer cracking during wire bonding, comprising: providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer;forming a polymer layer on the passivation layer;forming an adhesive layer selected from the group consisting of Ti, TiW and Cr on the polymer layer;forming a top metal layer selected from the group consisting of Ag, Pt, Ru and Rh on the adhesive layer; andbonding a wire onto the top metal layer to form a wire bond thereon.

66. A method for preventing polymer cracking during wire bonding, comprising: providing an integrated circuit (IC) die having thereon a passivation layer and a plurality of first bonding pads exposed by respective openings in the passivation layer;forming a polymer layer on the passivation layer;forming an adhesive layer selected from the group consisting of Ti, TiW and Cr on the polymer layer;forming a top metal layer selected from the group consisting of Cu, Ni and Au on the adhesive layer; andbonding a wire onto the top metal layer to form a wire bond thereon.