Cylindrical bonding structure and method of manufacture

• US 20030127734A1
• Filed: 01/22/2002
• Published: 07/10/2003
• Est. Priority Date: 01/07/2002
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lee, Jin-Yuan, Chou, Chien-Kang, Lin, Shih-Hsiung, Kuo, Hsi-Shan
• Application Number:
  US10/055,580
• Publication Number:
  US 20030127734A1
• Time in Patent Office: Days
• US Class Current: 257/737
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/05552 in top view
• CPC Class Codes: H01L 2224/05572 the external layer extending out of an opening
• CPC Class Codes: H01L 2224/05611 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/05639 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05647 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05655 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05657 Cobalt [Co] as principal constituent
• CPC Class Codes: H01L 2224/05664 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/05666 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/05671 Chromium [Cr] as principal constituent
• CPC Class Codes: H01L 2224/05672 Vanadium [V] as principal constituent
• CPC Class Codes: H01L 2224/05684 Tungsten [W] as principal constituent
• CPC Class Codes: H01L 2224/11462 Electroplating
• CPC Class Codes: H01L 2224/1147 using a lift-off mask
• CPC Class Codes: H01L 2224/11474 Multilayer masks
• CPC Class Codes: H01L 2224/11849 Reflowing
• CPC Class Codes: H01L 2224/11906 with modification of the same mask
• CPC Class Codes: H01L 2224/13017 being non uniform along the bump connector
• CPC Class Codes: H01L 2224/13022 : the bump connector being at least partially embedded in the surface
• CPC Class Codes: H01L 2224/1308 : being stacked
• CPC Class Codes: H01L 2224/13083 : Three-layer arrangements
• CPC Class Codes: H01L 2224/13099 : Material
• CPC Class Codes: H01L 2224/13109 : Indium [In] as principal constituent
• CPC Class Codes: H01L 2224/13111 : Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/13113 : Bismuth [Bi] as principal constituent
• CPC Class Codes: H01L 2224/13116 : Lead [Pb] as principal constituent
• CPC Class Codes: H01L 2224/13118 : Zinc [Zn] as principal constituent
• CPC Class Codes: H01L 2224/1312 : Antimony [Sb] as principal constituent
• CPC Class Codes: H01L 2224/13123 : Magnesium [Mg] as principal constituent
• CPC Class Codes: H01L 2224/13139 : Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/13144 : Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/13147 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/13155 : Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/13609 : Indium [In] as principal constituent
• CPC Class Codes: H01L 2224/16145 : the bodies being stacked
• CPC Class Codes: H01L 2224/16237 : the bump connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/29099 : Material
• CPC Class Codes: H01L 2224/81191 : wherein the bump connectors are disposed only on the semiconductor or solid-state body
• CPC Class Codes: H01L 2225/06513 : Bump or bump-like direct electrical connections between devices, e.g. flip-chip connection, solder bumps
• CPC Class Codes: H01L 24/03 : Manufacturing methods
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• CPC Class Codes: H01L 24/11 : Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 24/13 : of an individual bump connector
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• CPC Class Codes: H01L 25/50 : Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00013 : Fully indexed content
• 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 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01012 : Magnesium [Mg]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01024 : Chromium [Cr]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/0103 : Zinc [Zn]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/01051 : Antimony [Sb]
• CPC Class Codes: H01L 2924/01073 : Tantalum [Ta]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/013 : Alloys
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/04953 : TaN
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/14 : Integrated circuits

Abstract

A cylindrical bonding structure and its method of manufacture. The cylindrical bonding structure is formed over the bonding pad of a silicon chip and the chip is flipped over to connect with a substrate board in the process of forming a flip-chip package. The cylindrical bonding structure mainly includes a conductive cylinder and a solder block. The conductive cylinder is formed over the bonding pad of the silicon chip and the solder block is attached to the upper end of the conductive cylinder. The solder block has a melting point lower than the conductive cylinder. The solder block can be configured into a cylindrical, spherical or hemispherical shape. To fabricate the cylindrical bonding structure, a patterned mask layer having a plurality of openings that correspond in position to the bonding pads on the wafer is formed over a silicon wafer. Conductive material is deposited into the openings to form conductive cylinders and finally a solder block is attached to the end of each conductive cylinder.

Claims

1. A cylindrical bonding structure on a chip having one or more bonding pads thereon, comprising:

a conductive cylinder on the bonding pad of the chip; and

a solder block on the conductive cylinder, wherein the solder block is made from a material having a melting point lower than the conductive cylinder.

2. The structure of claim 1, wherein the bonding pad is the original bonding pad on the chip.

3. The structure of claim 1, wherein the chip further includes a redistribution circuit layer and the bonding pad is a pad on the redistribution circuit layer.

4. The structure of claim 1, wherein the solder block is a solder ball.

5. The structure of claim 1, wherein the solder block is a cylindrical solder cap.

6. The structure of claim 5, wherein the cylindrical solder cap has an outer diameter smaller than the conductive cylinder.

7. The structure of claim 1, wherein material forming the conductive cylinder is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

8. The structure of claim 1, wherein material forming the solder block is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

9. The structure of claim 1, wherein the structure further includes a ball contact metallic layer between the conductive cylinder and the bonding pad.

10. The structure of claim 1, wherein the structure further includes a transition layer between the conductive cylinder and the solder block.

11. The structure of claim 10, wherein the transition layer has at least one conductive layer.

12. A method of forming one or more cylindrical bonding structures over a silicon wafer having an active surface and at least one bonding pad on the active surface, comprising the steps of:

forming a ball contact metallic layer over the entire active surface of the silicon wafer, including the bonding pads;

forming a patterned mask layer over the ball contact metallic layer, wherein the first mask layer has at least one opening that corresponds in position to the bonding pad and exposes a portion of the ball contact metallic layer;

depositing conductive material into the opening to form a conductive cylinder over the ball contact metallic layer, wherein the conductive material only partially fills the opening;

depositing solder material into the remaining space of the opening to form at least one cylindrical solder cap on the upper surface of the conductive cylinder, wherein the solder material has a melting point lower than the conductive cylinder material; and

removing the mask layer and the ball contact metallic layer outside the conductive cylinder such that the remaining ball contact metallic layer, the conductive cylinder and the cylindrical solder cap together form the cylindrical bonding structure.

13. The method of claim 12, wherein the bonding pad is an original bonding pad on the wafer.

14. The method of claim 12, wherein the wafer further includes a redistribution circuit layer and the bonding pad is a pad on the redistribution circuit layer.

15. The method of claim 12, wherein after removing the mask layer and a portion of the ball contact metallic layer, further includes conducting a reflow operation to transform the cylindrical solder cap into a solder block.

16. The method of claim 12, wherein the step of depositing conductive material into the opening includes conducting an electroplating operation.

17. The method of claim 12, wherein the step of depositing solder material into the opening includes conducting an electroplating or a printing operation.

18. The method of claim 12, wherein after forming the conductive cylinder but before forming the cylindrical solder cap, further includes forming a transition layer over the upper surface of the conductive cylinder so that the cylindrical solder cap is formed over the transition layer.

19. The method of claim 18, wherein the transition layer has at least one conductive layer.

20. The method of claim 12, wherein material forming the conductive cylinder is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

21. The method of claim 12, wherein material forming the solder block is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

22. The method of claim 12, wherein material forming the mask layer includes photoresist.

23. The method of claim 12, wherein the step of forming the patterned mask layer includes forming a photoresist layer over the ball contact metallic layer and patterning the photoresist layer.

24. The method of claim 23, wherein the step of patterning the photoresist layer includes conducting a photo-exposure and developing the exposed photoresist layer.

25. A method of forming one or more cylindrical bonding structures over a silicon wafer having an active surface and at least one bonding pad on the active surface, comprising the steps of:

forming a ball contact metallic layer over the entire active surface of the silicon wafer, including the bonding pads;

forming a patterned mask layer over the ball contact metallic layer, wherein the mask layer has at least one opening that corresponds in position to the bonding pad and exposes a portion of the ball contact metallic layer;

depositing conductive material into the opening to form a conductive cylinder over the ball contact metallic layer, wherein the conductive material only partially fills the opening;

removing the mask layer and the ball contact metallic layer outside the conductive cylinder; and

attaching a solder ball onto the upper surface of the conductive cylinder such that the remaining ball contact metallic layer, the conductive cylinder and the solder ball together form the cylindrical bonding structure.

26. The method of claim 25, wherein the bonding pad is the original bonding pad on the wafer.

27. The method of claim 25, wherein the wafer further has a redistribution circuit layer and the bonding pads are pads on the redistribution circuit layer.

28. The method of claim 25, wherein the step of depositing conductive material into the opening includes conducting an electroplating operation.

29. The method of claim 25, wherein after forming the conductive cylinder but before attaching the solder ball, further includes forming a transition layer on the upper surface of the conductive cylinder so that the solder ball is attached to the transition layer.

30. The method of claim 29, wherein the transition layer has at least one conductive layer.

31. The method of claim 25, wherein material forming the conductive cylinder is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

32. The method of claim 25, wherein material forming the solder ball is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

33. The method of claim 25, wherein material forming the mask layer includes photoresist.

34. The method of claim 25, wherein the step of forming the patterned mask layer includes forming a photoresist layer over the ball contact metallic layer and patterning the photoresist layer.

35. The method of claim 34, wherein the step of patterning the photoresist layer includes conducting a photo-exposure and developing the exposed photoresist layer.

36. A cylindrical bonding structure on a silicon chip such that the structure may flip over and connect with a substrate, wherein the chip has at least one bonding pad and the substrate has a substrate surface having a patterned solder mask and at least one junction pad thereon, and the solder mask layer has at least an opening that exposes the junction pad, the cylindrical bonding structure comprising:

a conductive cylinder on the bonding pad of the chip; and

a cylindrical solder cap on the conductive cylinder, wherein the cylindrical solder cap has an outer diameter smaller than the diameter of the opening in the solder mask and a length greater than the depth of the opening, and the solder material has a melting point lower than the conductive cylinder material.

37. The structure of claim 36, wherein the bonding pad is the original bonding pad on the chip.

38. The structure of claim 36, wherein the chip further includes a redistribution circuit layer and the bonding pad is a pad on the redistribution circuit layer.

39. The structure of claim 36, wherein material forming the conductive cylinder is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

40. The structure of claim 36, wherein material forming the cylindrical solder cap is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

41. The structure of claim 36, wherein the structure further includes a ball contact metallic layer between the conductive cylinder and the bonding pad.

42. The structure of claim 36, wherein the structure further includes a transition layer between the conductive cylinder and the cylindrical solder cap.

43. The structure of claim 42, wherein the transition layer has at least one conductive layer.

44. A method of forming one or more cylindrical bonding structures over a silicon wafer having an active surface and at least one bonding pad on the active surface, comprising the steps of:

forming a ball contact metallic layer over the entire active surface of the silicon wafer, including the bonding pads;

forming a patterned first mask layer over the ball contact metallic layer, wherein the first mask layer has at least one opening that corresponds in position to the bonding pad and exposes a portion of the ball contact metallic layer;

depositing conductive material into the opening to form a conductive cylinder over the ball contact metallic layer;

forming a patterned second mask layer over the first mask layer, wherein the second mask layer has at least one opening than exposes a portion of the conductive cylinder;

depositing solder material into the opening to form a cylindrical solder cap over the conductive cylinder, wherein the solder material has a melting point lower than the conductive cylinder material; and

removing the first mask layer, the second mask layer and the ball contact metallic layer outside the conductive cylinder such that the remaining ball contact metallic layer, the conductive cylinder and the cylindrical solder cap together form the cylindrical bonding structure.

45. The method of claim 44, wherein the bonding pad is the original bonding pad on the wafer.

46. The method of claim 44, wherein the wafer further has a redistribution circuit layer and the bonding pads are pads on the redistribution circuit layer.

47. The method of claim 44, wherein the step of depositing conductive material into the first mask layer opening includes conducting an electroplating operation.

48. The method of claim 44, wherein the step of depositing solder material into the second mask layer opening includes conducting an electroplating operation.

49. The method of claim 44, wherein after forming the conductive cylinder but before the cylindrical solder cap, further includes forming a transition layer on the upper surface of the conductive cylinder so that the cylindrical solder cap is formed over the transition layer.

50. The method of claim 49, wherein the transition layer has at least one conductive layer.

51. The method of claim 44, wherein material forming the conductive cylinder is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

52. The method of claim 44, wherein material forming the solder material is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

53. The method of claim 44, wherein material forming the first mask layer includes photoresist.

54. The method of claim 44, wherein the step of forming the patterned first mask layer includes forming a photoresist layer over the ball contact metallic layer and patterning the photoresist layer.

55. The method of claim 54, wherein the step of patterning the photoresist layer includes conducting a photo-exposure and developing the exposed photoresist layer.

56. The method of claim 44, wherein material forming the second mask layer includes photoresist.

57. The method of claim 44, wherein the step of forming the patterned second mask layer includes forming a photoresist layer over the first mask layer and patterning the photoresist layer.

58. The method of claim 57, wherein the step of patterning the photoresist layer includes conducting a photo-exposure and developing the exposed photoresist layer.

59. A method of connecting a chip to a substrate to form a flip-chip package, wherein the chip has an active surface having at least a bonding pad thereon, the substrate has a substrate surface having a patterned solder mask and at least one junction pad thereon, and the solder mask has at least one opening that exposes the junction pad, the method comprising the steps of:

forming a cylindrical bonding structure on the bonding pad of the chip, wherein the cylindrical bonding structure comprises a conductive cylinder and a solder block, the bottom surface of the conductive cylinder is on top of the bonding pad and the bottom surface of the solder block is on the upper surface of the conductive cylinder, and the solder block has a melting point lower than the conductive cylinder;

flipping over the active surface of the chip to face the substrate surface of the substrate such that the upper surface of the solder block contacts the junction pad; and

conducting a reflow process to melt the solder block material so that the conductive cylinder and the junction pad are joined together.

60. The method of claim 59, wherein the bonding pad is the original bonding pad on the chip.

61. The method of claim 59, wherein the wafer further has a redistribution circuit layer and the bonding pads are pads on the redistribution circuit layer.

62. The method of claim 59, wherein material forming the conductive cylinder is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

63. The method of claim 59, wherein material forming the solder block is selected from a group consisting of tin, lead, copper, gold, silver, zinc, bismuth, magnesium, antimony, indium and an alloy of the aforementioned metals.

64. The method of claim 59, wherein the solder block is a cylindrical solder cap.

65. The method of claim 64, wherein the cylindrical solder cap has an outer diameter smaller than the opening diameter on the solder mask.

66. The method of claim 65, wherein the cylindrical solder cap has a length greater than the depth of the opening on the solder mask.

67. The method of claim 59, wherein the cylindrical bonding structure further includes a ball contact metallic layer between the conductive cylinder and the bonding pad on the chip.

68. The method of claim 59, wherein the cylindrical bonding structure further includes a transition layer between the conductive cylinder and the solder block.

69. The method of claim 68, wherein the transition layer has at least a conductive layer.