Flip chip bonding tool tip

• US 20050109817A1
• Filed: 09/15/2004
• Published: 05/26/2005
• Est. Priority Date: 02/25/1999
• Status: Active Grant

• Current Assignee: Anza Technology, Inc.
• Original Assignee: Steven F Reiber (Anza Technology, Inc.)
• Inventors: Reiber, Steven F.
• Granted Patent: US 7,389,905 B2
• Time in Patent Office: Days
• US Class Current: 228/49.600
• CPC Class Codes: B23K 20/004 Wire welding
• CPC Class Codes: B23K 20/005 Capillary welding
• CPC Class Codes: B23K 20/025 Bonding tips therefor
• CPC Class Codes: B23K 2101/32 Wires
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48 of an individual wire connector
• CPC Class Codes: H01L 2224/75745 in the upper part of the bonding apparatus, e.g. in the bonding head
• CPC Class Codes: H01L 2224/78302 Shape
• CPC Class Codes: H01L 2224/851 the connector being supplied to the parts to be connected in the bonding apparatus
• CPC Class Codes: H01L 2224/85205 Ultrasonic bonding
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/85 using a wire connector wire bonding in general B23K20/004
• 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 2924/00014 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 Silicon [Si]
• CPC Class Codes: H01L 2924/01021 Scandium [Sc]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/0104 : Zirconium [Zr]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• 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 2924/01105 : Rare earth metals
• CPC Class Codes: H01L 2924/04941 : TiN
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/19043 : being a resistor

Abstract

A flip chip bonding tool tip comprising a dissipative material with a resistance low enough to prevent a discharge of a charge to a device being bonded and high enough to avoid current flow large enough to damage the device being bonded is disclosed. Methods for manufacturing a dissipative material for use in a flip chip bonding tool tip are further disclosed.

Claims

1. A flip chip bonding tool tip for use in flip chip bonding machines for connecting leads on integrated circuit bonding pads, the flip chip bonding tool tip comprising a dissipative material, wherein the dissipative material has a resistance low enough to prevent a discharge of a charge to a device being bonded and high enough to avoid current flow large enough to damage the device being bonded.

2. The flip chip bonding tool tip of claim 1, wherein the dissipative material comprises a resistance in a range of 10² to 10¹² ohms.

3. The flip chip bonding tool tip of claim 1, wherein the flip chip bonding tool tip comprises a tube for vacuum.

4. The flip chip bonding tool tip of claim 1, wherein the flip chip bonding tool tip comprises grooves.

5. The flip chip bonding tool tip of claim 1, wherein the flip chip bonding tool tip comprises a high enough stiffness to resist bending when hot and a high enough abrasiveness so as to function for at least two uses.

6. The flip chip bonding tool tip of claim 1, wherein the dissipative material comprises an extrinsic semi-conducting material that has dopant atoms in an appropriate concentration and valence states to produce the resistance.

7. The flip chip bonding tool tip of claim 6, wherein the dissipative material further comprises a polycrystalline silicon carbide.

8. The flip chip bonding tool tip of claim 7, wherein the polycrystalline silicon carbide is uniformly doped with boron.

9. The flip chip bonding tool tip of claim 1, wherein the dissipative material comprises a doped semi-conductor formed on an insulating core.

10. The flip chip bonding tool tip of claim 9, wherein the insulating core is comprised of diamond.

11. The flip chip bonding tool tip of claim 10, wherein the doped semi-conductor further comprises an outer surface of the diamond that is ion implanted with boron.

12. The flip chip bonding tool tip of claim 1, wherein the dissipative material comprises a doped semi-conductor formed on a conducting core.

13. The flip chip bonding tool tip of claim 12, wherein the conducting core is comprised of a cobalt-bonded tungsten carbide.

14. The flip chip bonding tool tip of claim 13, wherein the cobalt-bonded tungsten carbide is coated with titanium nitride carbide.

15. A method of manufacturing a dissipative material for use in a flip chip bonding tool tip, wherein the dissipative material has a resistance low enough to prevent a discharge of a charge to a device being bonded and high enough to avoid current flow large enough to damage the device being bonded, comprising:

mixing particles of a composition appropriate for forming the dissipative material with solvents, dispersants, binders, and sintering aids to form a mixture;

molding the mixture into at least one wedge;

drying the at least one wedge;

heating the dried at least one wedge to a temperature sufficient to remove the dispersants and binders;

further heating the heated at least one wedge to a temperature to sinter the particles together into a solid structure with low porosity; and

cooling the solid structure.

16. The method of claim 15 further comprising machining the cooled solid structure to a required size, shape, or tolerance.

17. The method of claim 15, wherein heating the dried at least one wedge to remove dispersants and binders occurs at a temperature of 500-2500 degrees Celsius.

18. The method of claim 15, wherein further heating the heated at least one wedge is heated to sinter the particles together into a solid structure with low porosity occurs at a temperature of at least 4000 degrees Celsius.

19. The method of claim 15 wherein the binders are selected from the group consisting of magnesia, yttria, boron, carbon colloidal silica, alumina solvent, ethyl silicate, phosphate, yttrium, or a rare earth metal oxide.

20. The method of claim 15 wherein the solvents are selected from the group consisting of magnesia, ytrria, boron, carbon colloidal silica, alumina solvent, ethyl silicate, phosphate, yttrium, or a rare earth metal oxide.

21. The method of claim 15 further comprising treating the cooled solid structure to produce a desired surface layer.

22. The method of claim 21 wherein treating the cooled solid structure to produce a desired surface layer comprises ion implementation.

23. The method of claim 21 wherein treating the cooled solid structure to produce a desired surface layer comprises vapor deposition.

24. The method of claim 21 wherein treating the cooled solid structure to produce a desired surface layer comprises chemical vapor deposition.

25. The method of claim 21 wherein treating the cooled solid structure to produce a desired surface layer comprises physical deposition.

26. The method of claim 21 wherein treating the cooled solid structure to produce a desired surface layer comprises electroplating deposition.

27. The method claim 21 wherein treating the cooled solid structure to produce a desired surface layer comprises neutron bombardment.

28. The method of claim 15 further comprising heat treatment of the cooled solid structure in a controlled atmosphere to produce at least one desired layer property.

29. The method of claim 28 wherein heat treatment of the cooled solid structure in a controlled atmosphere to produce at least one desired layer property comprises diffusion.

30. The method of claim 28 wherein heat treatment of the cooled solid structure in a controlled atmosphere to produce at least one desired layer property comprises re-crystallization.

31. The method of claim 28 wherein heat treatment of the cooled solid structure in a controlled atmosphere to produce at least one desired layer property comprises dopant activation.

32. The method of claim 28 wherein heat treatment of the cooled solid structure in a controlled atmosphere to produce at least one desired layer property comprises valence changes of metallic ions.

33. A method of manufacturing a dissipative material for use in a flip chip bonding tool tip, wherein the dissipative material has a resistance low enough to prevent a discharge of a charge to a device being bonded and high enough to avoid current flow large enough to damage the device being bonded comprising:

mixing particles of a composition appropriate for forming the dissipative material with binders and sintering aids to form a mixture;

pressing the mixture in a mold at a high enough temperature to cause consolidation and binding of the particles into a solid structure with low porosity; and

removing the solid structure from the mold.

34. The method of claim 33, further comprising machining the solid structure to a required size, shape, or tolerance.

35. The method of claim 33, wherein pressing the mixture in a mold occurs as a temperature between 1000 and 2500 degrees Celsius.

36. The method of claim 33 wherein the binders are selected from the group consisting of magnesia, yttria, boron, carbon colloidal silica, alumina solvent, ethyl silicate, phosphate, yttrium, or a rare earth metal oxide.

37. The method of claim 33 further comprising treating the solid structure to produce a desired surface layer.

38. The method of claim 37 wherein treating the solid structure to produce a desired surface layer comprises ion implementation.

39. The method of claim 37 wherein treating the solid structure to produce a desired surface layer comprises vapor deposition.

40. The method of claim 37 wherein treating the solid structure to produce a desired surface layer comprises chemical vapor deposition.

41. The method of claim 37 wherein treating the solid structure to produce a desired surface layer comprises physical deposition.

42. The method of claim 37 wherein treating the solid structure to produce a desired surface layer comprises electroplating deposition.

43. The method of claim 37 wherein treating the solid structure to produce a desired surface layer comprises neutron bombardment.

44. The method of claim 33 further comprising heat treatment of the solid structure in a controlled atmosphere to produce at least one desired layer property.

45. The method of claim 44 wherein heat treatment of the solid structure in a controlled atmosphere to produce at least one desired layer property comprises diffusion.

46. The method of claim 44 wherein heat treatment of the solid structure in a controlled atmosphere to produce at least one desired layer property comprises re-crystallization.

47. The method of claim 44 wherein heat treatment of the solid structure in a controlled atmosphere to produce at least one desired layer property comprises dopant activation.

48. The method of claim 44 wherein heat treatment of the solid structure in a controlled atmosphere to produce at least one desired layer property comprises valence changes of metallic ions.

49. A method of manufacturing a dissipative material for use in a flip chip bonding tool tip, wherein the dissipative material has a resistance low enough to prevent a discharge of a charge to a device being bonded and high enough to avoid current flow large enough to damage the device being bonded comprising:

melting at least one metal of a composition appropriate for forming the dissipative material in a non-reactive crucible;

casting the melted at least one metal into an ingot;

rolling the ingot into a rolled ingot;

extruding the rolled ingot into an extruded material;

drawing the extruded material into a drawn material; and

pressing the drawn material into a pressed material.

50. The method of claim 49, further comprising machining the pressed material to a required size, shape, or tolerance.

51. The method of claim 49 further comprising treating the pressed material to produce a desired surface layer.

52. The method of claim 51 wherein treating the pressed material to produce a desired surface layer comprises vapor deposition.

53. The method of claim 51 wherein treating the pressed material to produce a desired surface layer comprises chemical vapor deposition.

54. The method of claim 51 wherein treating the pressed material to produce a desired surface layer comprises physical deposition.

55. The method of claim 51 wherein treating the pressed material to produce a desired surface layer comprises electroplating deposition.

56. The method of claim 49 further comprising heat treatment of the pressed material in a controlled atmosphere to produce at least one desired layer property.

57. The method of claim 56 wherein heat treatment of the pressed material in a controlled atmosphere to produce at least one desired layer property comprises diffusion.

58. The method of claim 56 wherein heat treatment of the pressed material in a controlled atmosphere to produce at least one desired layer property comprises re-crystallization.

59. The method of claim 56 wherein heat treatment of the pressed material in a controlled atmosphere to produce at least one desired layer property comprises dopant activation.

60. The method of claim 56 wherein heat treatment of the pressed material in a controlled atmosphere to produce at least one desired layer property comprises valence changes of metallic ions.

61. A device comprising a flip chip bonding tool tip comprising a dissipative material, wherein the tip is positioned to come in contact with a device being bonded, and wherein a current produced by static charge generated during bonding is allowed to flow, and the dissipative material has a resistance low enough to prevent a discharge of charge to a device being bonded and high enough so that the current flow is not large enough to damage the device being bonded.

62. The device of claim 61, wherein the current flow allowed is no more than 3 milliamps.

63. A method of bonding using a dissipative flip chip bonding tool tip comprising:

providing a flip chip bonding tool tip comprising a dissipative material that has a resistance low enough to prevent a discharge of charge to a device being bonded and high enough so that the current flow is not large enough to damage a device being bonded;

positioning the flip chip bonding tool tip so that the dissipative material electrically couples with the device being bonded during bonding;

forming a bond on the device being bonded; and

allowing a current flow that is produced by static charge generated by the bonding.

64. The method of claim 63 wherein the current flow allowed is no more than 3 milliamps.

65. A method of using an electrically dissipative flip chip bonding tool tip, having a resistance in the range of 10² to 10¹² ohms, comprising:

providing the electrically dissipative flip chip bonding tool tip;

bonding a material to a device; and

allowing an essentially smooth current to dissipate to the device, the current being low enough so as not to damage the device being bonded and high enough to avoid a build up of charge that could discharge to the device being bonded and damage the device being bonded.

66. The method of claim 65, wherein bonding comprises:

heating the electrically dissipative flip chip bonding tool tip using electrical resistive heating; and

using the electrically dissipative flip chip bonding tool tip to melt a bonding material.

67. The method of claim 65, wherein bonding comprises scrubbing the material laterally to cause the material to flow.

68. The method of claim 65, further comprising establishing a potential between the electrically dissipative flip chip bonding tool tip and the device being bonded.

69. The method of claim 68, wherein establishing the potential between the electrically dissipative flip chip bonding tool tip and the device being bonded further comprises grounding leads on the device being bonded.

70. The method of claim 65 further comprising placing the electrically dissipative flip chip bonding tool tip in electrical contact with the device being bonded.

71. The method of claim 70 further comprising feeding wire through a tubular channel in the electrically dissipative flip chip bonding tool tip prior to placing it in contact with the device being bonded.

72. The method of claim 65 further comprising:

providing an electrical discharge at the electrically dissipative flip chip bonding tool tip to melt a bit of wire; and

forming the bit of wire into a bonding ball.

73. The method of claim 72 further comprising causing the bonding ball to make intimate contact with the device, thereby initiating dissipation of charge.

74. The method of claim 72 further comprising moving the electrically dissipative flip chip bonding tool tip from the device, with the wire being fed as the electrically dissipative flip chip bonding tool tip moves onto a different point of the device.

75. A method for using a flip chip bonding tool in microelectronic assembly, comprising:

providing a flip chip bonding machine capable of being equipped with a flip chip bonding tool;

equipping the flip chip bonding machine with the flip chip bonding tool, wherein the flip chip bonding tool has a tip comprised of a dissipative material wherein the dissipative material has a resistance low enough to prevent a discharge of a charge to a device being bonded and high enough to avoid current flow large enough to damage the device being bonded;

providing a bonding material that is thermally and electrically conductive;

melting the bonding material so that it becomes substantially spherical in shape; and

electrically connecting an at least one component to a substrate by means of the flip chip bonding tool tip pressing the substantially spherical-shaped bonding material against a chip bond pad, wherein the substantially spherical bonding material is pressed to form a conductive bump.

76. The method of claim 75 further comprising coining the conductive bump.