Projected contact structures for engaging bumped semiconductor devices and methods of making the same
First Claim
1. A contact structure for making electrical contact with a deformable conductive bump, said contact structure comprising a contact pad including a plurality of non-planar surfaces substantially radially oriented about a central planar area, said plurality of non-planar surfaces including conductive regions thereon.
5 Assignments
0 Petitions
Accused Products
Abstract
A bumped semiconductor device contact structure is disclosed including at least one non-planar contact pad having a plurality of projections extending therefrom for contacting at least one solder ball of a bumped integrated circuit (IC) device, such as a bumped die and a bumped packaged IC device. The projections are arranged to make electrical contact with the solder balls of a bumped IC device without substantially deforming the solder ball. Accordingly, reflow of solder balls to reform the solder balls is not necessary with the contact pad of the present invention. Such a contact pad may be provided on various testing equipment such as probes and the like and may be used for both temporary and permanent connections. Also disclosed is an improved method of forming the contact pads by etching and deposition.
118 Citations
114 Claims
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1. A contact structure for making electrical contact with a deformable conductive bump, said contact structure comprising a contact pad including a plurality of non-planar surfaces substantially radially oriented about a central planar area, said plurality of non-planar surfaces including conductive regions thereon.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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2. The contact structure of claim 1, wherein said plurality of non-planar surfaces exhibits substantial knife edges at its outermost extents.
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3. The contact structure of claim 1, wherein said plurality of non-planar surfaces comprises elongated elements and exhibiting longitudinally-extending substantial knife edges.
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4. The contact structure of claim 3, wherein at least a portion of each of said longitudinal-extending substantial knife edges lies at an acute angle to a surface of said central planar area.
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5. The contact structure of claim 4, wherein said longitudinal-extending substantial knife edges extend from said surface of said contact structure proximate said central planar area and increase in elevation radially away therefrom.
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6. The contact structure of claim 5, wherein each of said plurality of non-planar surfaces is substantially identical in configuration and dimensions.
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7. The contact structure of claim 1, wherein said non-planar surfaces are configured to make penetrating contact with a portion of an exterior surface of said deformable conductive bump.
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8. The contact structure of claim 7, wherein said plurality of non-planar surfaces comprises a cradle for centralizing said deformable conductive bump over said central planar area prior to said penetrating contact.
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9. The contact structure of claim 1, wherein said contact pad is conductive, and further comprising a substrate supporting said contact pad.
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10. The contact structure of claim 9, further comprising an insulating material interposed between said conductive regions of said non-planar surfaces and said substrate.
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11. The contact structure of claim 10, wherein said plurality of non-planar surfaces and said contact pad comprise contiguous conductive surfaces, and said insulating material comprises an insulating layer interposed between said substrate and said conductive regions.
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12. The contact structure of claim 11, wherein said plurality of non-planar surfaces comprises material of said substrate, and said conductive regions comprise a layer of conductive material disposed over said substrate.
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13. The contact structure of claim 9, wherein said plurality of non-planar surfaces comprises conductive material deposited over said contact pad.
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14. The contact structure of claim 9, further including a conductive trace extending from said contact pad.
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15. The contact structure of claim 1, wherein said plurality of non-planar surfaces comprises elongated elements arranged about said central planar area and exhibiting elongated substantial knife edges.
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16. The contact structure of claim 15, wherein said elongated substantial knife edges lie in substantially parallel relationship to said central planar area.
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17. The contact structure of claim 16, wherein said plurality of non-planar surfaces is arcuate and substantially defines a circle about said central planar area.
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18. The contact structure of claim 17, wherein ends of said elongated elements are in adjacent, non-abutting proximity.
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19. The contact structure of claim 16, wherein said plurality of non-planar surfaces substantially bounds said central planar area.
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20. The contact structure of claim 1, wherein said plurality of non-planar surfaces is arranged in a plurality of groups about said central planar area, the non-planar surfaces of each of said plurality of groups lying a different distance from a center of said central planar area.
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21. The contact structure of claim 20, wherein said projections of each group lie at substantially the same distance from said center as other non-planar surfaces of the same group.
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22. The contact structure of claim 20, wherein said non-planar surfaces of each of said plurality of groups extend above said central planar area surface a different distance than the non-planar surfaces of any other group of said plurality of groups.
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23. The contact structure of claim 20, wherein said plurality of non-planar surfaces comprises elongated elements exhibiting elongated knife edges and having ends proximate other non-planar surfaces of the same group of said plurality of groups.
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24. The contact structure of claim 23, wherein said plurality of non-planar surfaces is arcuate and defines a series of concentric, substantially circular frames.
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25. The contact structure of claim 20, wherein said plurality of groups increases in height above a surface of said central planar area with increased distance from said central planar area.
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26. The contact structure of claim 20, wherein said plurality of non-planar surfaces comprises substantially symmetrical, pyramidal or conical elements extending above said central planar area.
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27. The contact structure of claim 26, wherein said plurality of groups increases in height above a surface of said central planar area plane with increased distance from said central planar area.
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28. The contact structure of claim 20, wherein said plurality of non-planar surfaces comprises substantially symmetrical, pyramidal or conical elements extending above a surface of said central planar area.
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29. The contact structure of claim 28, wherein said plurality of groups increases in height above a surface of said central planar area plane with increased distance from said central planar area.
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30. The contact structure of claim 29, wherein at least some of said substantially symmetrical pyramidal or conical elements include a flat outermost tip surface.
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31. The contact structure of claim 1, further comprising a test probe tip supporting said contact pad.
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32. The contact structure of claim 1, wherein said contact pad comprises a plurality of contact pads arranged on a wafer-scale substrate for simultaneous contact with a plurality of unsingulated semiconductor dice fabricated on a semiconductor wafer.
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2. The contact structure of claim 1, wherein said plurality of non-planar surfaces exhibits substantial knife edges at its outermost extents.
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33. A semiconductor device assembly comprising:
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at least one semiconductor die including a plurality of solder bumps thereon;
a contact structure comprising at least one contact pad configured to align with at least one solder bump of said plurality of solder bumps of said at least one semiconductor die; and
a plurality of projections protruding from each contact pad of said at least one contact pad, said plurality of projections adjacent a substantially central projection-free portion of each of said contact pad and in communication with a solder bump of said plurality of solder bumps. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68)
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34. The assembly of claim 33, wherein said contact structure comprises a probe configured for functional testing of said at least one semiconductor die.
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35. The assembly of claim 33, wherein said contact structure comprises a carrier substrate.
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36. The assembly of claim 33, wherein a central, bottom portion of each of said plurality of solder bumps lies proximate a corresponding contact pad of said at least one contact pad over said projection-free contact pad portion thereof.
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37. The assembly of claim 36, wherein said solder bumps of said plurality vary in height, and at least one projection of each of said at least one contact pad penetrates an exterior surface of its associated solder bump.
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38. The assembly of claim 33, wherein said plurality of projections exhibits substantial knife edges at its outermost extents.
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39. The assembly of claim 33, wherein said plurality of projections comprises elongated elements arranged to extend substantially radially from said projection-free contact pad portions and exhibiting longitudinally-extending substantial knife edges.
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40. The assembly of claim 39, wherein at least a portion of each of said longitudinal-extending substantial knife edges lies at an acute angle to a substantially planar surface of said contact structure.
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41. The assembly of claim 40, wherein said longitudinally-extending substantial knife edges extend from said at least one contact pad proximate said projection-free contact pad portions and increase in elevation radially away therefrom.
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42. The assembly of claim 41, wherein each of said plurality of projections of a given contact pad is substantially identical in configuration and dimensions.
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43. The assembly of claim 33, wherein said plurality of projections comprises a cradle for centralizing said plurality of solder bumps over said projection-free contact pad portion prior to communication with said solder bump.
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44. The assembly of claim 33, wherein said at least one contact pad is conductive.
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45. The assembly of claim 44, further comprising an insulating material interposed between said plurality of projections and said contact structure.
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46. The assembly of claim 45, wherein said plurality of projections and said at least one contact pad comprise contiguous conductive surfaces, and said insulating material comprises an insulating layer interposed between said contact structure and said contiguous conductive surfaces.
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47. The assembly of claim 46, wherein said plurality of projections comprises material of said contact structure, and said contiguous conductive surfaces comprise a layer of conductive material disposed over said contact structure.
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48. The assembly of claim 44, wherein said plurality of projections comprises conductive material deposited over said at least one contact pad.
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49. The assembly of claim 44, further including conductive traces extending from said at least one contact pad.
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50. The assembly of claim 33, wherein said plurality of projections comprises elongated elements arranged about said projection-free contact pad portions and exhibiting elongated substantial knife edges.
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51. The assembly of claim 50, wherein said elongated substantial knife edges lie in substantially parallel relationship to a substantially planar surface of said contact structure.
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52. The assembly of claim 51, wherein projections of said plurality of projections are arcuate and substantially define circles about said projection-free contact pad portions.
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53. The assembly of claim 52, wherein ends of said elongated elements are in adjacent, non-abutting proximity.
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54. The assembly of claim 51, wherein said plurality of projections substantially bound said projection-free contact pad portions.
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55. The assembly of claim 54, wherein said plurality of projections comprises elongated linear elements defining at least one rectangular frame about said projection-free contact pad portions.
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56. The assembly of claim 55, wherein ends of said elongated linear elements lie adjacent corners of said at least one rectangular frame in non-abutting mutual relationship.
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57. The assembly of claim 55, wherein each of said plurality of projections is substantially identical in configuration and dimensions.
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58. The assembly of claim 50, wherein said plurality of projections comprises a cradle for centralizing said solder bump of said plurality over said projection-free contact pad portions prior to communication with said solder bump.
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59. The assembly of claim 58, wherein said plurality of projections of each contact pad of said at least one contact pad is arranged in a plurality of groups about said projection-free contact pad portions, the projections of each of said plurality of groups lying a different distance from a center of said projection-free contact pad portions.
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60. The assembly of claim 59, wherein said projections of each group of said plurality of groups lie at substantially the same distance from said center as other projections of the same group of said plurality of groups.
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61. The assembly of claim 59, wherein each of said plurality of groups of projections associated with a contact pad extends above that contact pad a different distance than the projections of any other group of said plurality of groups.
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62. The assembly of claim 61, wherein said plurality of projections comprises elongated elements exhibiting elongated knife edges and having ends proximate other projections of the same group.
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63. The assembly of claim 62, wherein said plurality of projections is linear and define a series of substantially concentric rectangular frames.
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64. The assembly of claim 62, wherein said plurality of projections are arcuate and define a series of concentric, substantially circular frames.
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65. The assembly of claim 60, wherein groups of said plurality of groups of projections increase in height above said substantially planar surface with increased distance from said projection-free contact pad portion.
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66. The assembly of claim 60, wherein said plurality of projections comprises substantially symmetrical, pyramidal or conical elements extending above a substantially planar surface of said contact structure.
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67. The assembly of claim 66, wherein at least some of said substantially symmetrical pyramidal or conical elements include a flat outermost tip surface.
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68. The structure of claim 33, wherein said at least one semiconductor die comprises a plurality of unsingulated semiconductor dice in wafer form and said contact structure comprises a wafer-scale substrate carrying said plurality of contact pads thereon for simultaneous contact with said plurality of unsingulated semiconductor dice.
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34. The assembly of claim 33, wherein said contact structure comprises a probe configured for functional testing of said at least one semiconductor die.
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69. A method for creating at least one projection body for engaging outer surfaces of conductive bumps without substantially deforming said outer surfaces of the conductive bumps, said method comprising:
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forming at least one masking block on a substrate blank;
subjecting said masked substrate to an oxidizing atmosphere to form at least one projection body thereon;
forming a second mask over said at least one projection body; and
refining said at least one projection body. - View Dependent Claims (70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114)
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70. The method according to claim 69, wherein said subjecting comprises exposing said masked substrate to steam and O2 at a temperature of approximately 950°
- C.
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71. The method according to claim 69, further comprising employing a wet etchant after said subjecting.
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72. The method according to claim 69 wherein said refining comprises subjecting said substrate to a second oxidizing atmosphere after said forming a second mask to further define said projection body.
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73. The method according to claim 69, wherein said forming at least one least one masking block comprises forming at least one masking block on a substrate blank, said substrate blank having a coefficient of thermal expansion matching a coefficient of thermal expansion of an underlying silicon die.
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74. The method according to claim 73, wherein said substrate blank is selected from the group consisting of monocrystalline silicon, silicon-on-glass, silicon-on sapphire, germanium and ceramic.
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75. The method according to claim 69, wherein said forming at least one masking block comprises:
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forming at least one mask on said substrate blank; and
patterning and etching said at least one mask selective to said substrate blank to form a hard mask including said at least one masking block patterned to define a location for said at least one projection body.
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76. The method according to claim 75, wherein said patterning and etching comprises etching with phosphoric acid.
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77. The method according to claim 75, wherein said forming at least one mask comprises placing a silicon nitride mask on said carrier substrate.
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78. The method according to claim 77, wherein said placing a silicon nitride mask comprises depositing said silicon nitride mask by chemical vapor deposition.
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79. The method according to claim 77, wherein said forming at least one mask comprises forming a first mask having a thickness of about 500 Å
- to 6000 Å
.
- to 6000 Å
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80. The method according to claim 69, wherein said refining comprises undercutting said second mask with an etchant that reacts with said substrate blank.
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81. The method according to claim 80, wherein said etchant comprises a mixture of KOH and H2O.
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82. The method according to claim 69, wherein said substrate blank comprises monocrystalline silicon, and said subjecting said masked substrate to an oxidizing atmosphere to form at least one projection body thereon comprises forming triangular cross-section, sharp projections.
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83. The method according to claim 82, wherein said refining comprises removing a top surface of said substrate blank faster than sidewalls of said at least one projection body.
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84. The method according to claim 83, wherein said refining comprises defining said sidewalls of said at least one projection body at an angle approximately 54°
- relative to a plane defined by said top surface of said substrate blank.
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85. The method according to claim 69, wherein said subjecting comprises defining a flat-topped, slope-walled, elongated projection body.
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86. The method according to claim 69, wherein said subjecting said substrate blank to an oxidizing atmosphere comprises defining a truncated, pyramidal projection body.
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87. The method according to claim 69, wherein subjecting said substrate blank to an oxidizing atmosphere comprises forming a closely-spaced array of projection bodies wherein no planar substrate blank surface extends between adjacent projection bodies.
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88. The method according to claim 69, further comprising forming an insulating layer over said at least one projection body and said substrate blank.
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89. The method according to claim 88, wherein said forming an insulating layer comprises exposing said substrate blank to a second oxidizing atmosphere.
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90. The method according to claim 88, wherein said forming an insulating layer comprises depositing said insulating layer by chemical vapor deposition.
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91. The method according to claim 88, further comprising forming a conductive layer over said insulating layer.
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92. The method according to claim 91, wherein said forming a conductive layer comprises forming said conductive layer of metal, said metal selected from the group consisting of aluminum (Al), iridium (Ir), copper (Cu), titanium (Ti), tungsten (W), tantalum (Ta), molybdenum (Mo), beryllium (Be) and alloys thereof.
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93. The method according to claim 69, wherein said at least one projection body extends upwardly from a contact area on said substrate blank and further comprising forming conductive traces extending from said contact area.
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94. The method according to claim 93, wherein said forming conductive traces comprises one of depositing a metal conductor and photopatterning and etching a metal layer.
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95. The method according to claim 91, wherein said forming a conductive layer comprises forming a non-metallic conductive layer.
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96. The method according to claim 95, wherein said forming a conductive layer comprises forming said conductive layer of phosphorous-doped polysilicon by LPCVD.
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97. The method according to claim 69, wherein said subjecting said substrate blank to an oxidizing atmosphere to form at least one projection body comprises creating said at least one projection body having a point at a narrow end of said at least one masking block and wherein said at least one masking block covers a flat mesa top on the at least one projection body.
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98. The method according to claim 97, wherein said refining comprises increasing the relative height of said at least one projection body and sharpening said point of said at least one projection body.
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99. The method according to claim 69, further comprising sharpening a point of said at least one projection body, said sharpening comprising:
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forming a third mask over said at least one projection body, said third mask being shorter and narrower than said at least one masking block and said second mask; and
etching said substrate blank to sharpen the point of said at least one projection body.
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100. The method according to claim 69, wherein said forming at least one masking block comprises forming an elongated trapezoidal, substantially triangular mask or a rectangular mask on said substrate blank.
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101. The method according to claim 69, wherein said subjecting said substrate blank to an oxidizing atmosphere creates a sloping knife-edge extending longitudinally along substantially an entire length of said at least one projection body defining said at least one projection body, said knife-edge beginning at a surface of said substrate blank at a narrow end of said at least one projection body.
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102. The method according to claim 69, wherein a first projection body of said at least one projection body and a second projection body of said at least one projection body comprise different relative heights.
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103. The method according to claim 69, wherein said refining comprises isotropically etching with a mixture of HF, HNO3 and H2O.
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104. The method according to claim 103, further comprising forming said at least one projection body to include arcuate and concave sidewalls.
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105. The method according to claim 104, further comprising controlling a radius of arc of said sidewalls by varying etch parameters.
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106. The method according to claim 69, further comprising:
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forming a third mask on said substrate blank after said subjecting said substrate blank to an oxidizing atmosphere to form said at least one projection body thereon, said third mask adjacent said at least one projection body; and
etching said substrate blank, thereby revealing a second projection body and defining said at least one projection body.
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107. The method according to claim 69, wherein said refining comprises exposing said substrate blank and said at least one projection body to a second oxidizing atmosphere.
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108. The method according to claim 107, wherein said exposing said substrate blank and said at least one projection body to a second oxidizing atmosphere comprises exposing said substrate blank and said at least one projection body to steam and O2 at a temperature of approximately 950°
- C.
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109. The method according to claim 107, wherein said exposing said substrate blank and said at least one projection body to a second oxidizing atmosphere comprises:
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undercutting said at least one projection body beneath said at least one masking block or said second mask; and
forming an oxide layer on exposed portions of said substrate blank.
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110. The method according to claim 109, further comprising removing said oxide layer from said substrate blank.
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111. The method according to claim 110, wherein said removing said oxide layer comprises exposing said substrate blank to a wet etchant.
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112. The method according to claim 69, wherein said subjecting comprises:
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undercutting said at least one projection body beneath said at least one masking block or said second mask; and
forming an oxide layer on exposed portions of said substrate blank.
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113. The method according to claim 112, further comprising removing said oxide layer from said substrate blank.
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114. The method according to claim 112, wherein said removing said oxide layer comprises exposing said substrate blank to a wet etchant.
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70. The method according to claim 69, wherein said subjecting comprises exposing said masked substrate to steam and O2 at a temperature of approximately 950°
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Specification
- Resources
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Current AssigneeJames M. Wark, Salman Akram
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Original AssigneeJames M. Wark, Salman Akram
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InventorsWark, James M., Akram, Salman
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current438/613
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CPC Class CodesG01R 1/06738 related to tip portionH01L 22/34 Circuits for electrically c...H01L 2224/0401 Bonding areas specifically ...H01L 2224/05551 comprising apertures or cav...H01L 2224/05552 in top viewH01L 2224/05553 being rectangularH01L 2224/05554 being squareH01L 2224/05555 being circular or ellipticH01L 2224/13 of an individual bump conne...H01L 2224/13099 MaterialH01L 2224/13111 Tin [Sn] as principal const...H01L 2224/13144 Gold [Au] as principal cons...H01L 2224/16 of an individual bump conne...H01L 2224/1601 StructureH01L 2224/81191 wherein the bump connectors...H01L 2224/81385 Shape, e.g. interlocking fe...H01L 2224/81801 Soldering or alloyingH01L 23/49811 Additional leads joined to ...H01L 23/49816 Spherical bumps on the subs...H01L 24/10 Bump connectors bumps on in...H01L 24/12 : Structure, shape, material ...H01L 24/13 : of an individual bump conne...H01L 24/81 : using a bump connectorH01L 2924/00 : Indexing scheme for arrange...H01L 2924/00014 : the subject-matter covered ...H01L 2924/01004 : Beryllium [Be]H01L 2924/01005 : Boron [B]H01L 2924/01006 : Carbon [C]H01L 2924/01013 : Aluminum [Al]H01L 2924/01015 : Phosphorus [P]H01L 2924/01019 : Potassium [K]H01L 2924/01022 : Titanium [Ti]H01L 2924/01027 : Cobalt [Co]H01L 2924/01029 : Copper [Cu]H01L 2924/01032 : Germanium [Ge]H01L 2924/01033 : Arsenic [As]H01L 2924/01042 : Molybdenum [Mo]H01L 2924/01047 : Silver [Ag]H01L 2924/01049 : Indium [In]H01L 2924/0105 : Tin [Sn]H01L 2924/01072 : Hafnium [Hf]H01L 2924/01073 : Tantalum [Ta]H01L 2924/01074 : Tungsten [W]H01L 2924/01075 : Rhenium [Re]H01L 2924/01077 : Iridium [Ir]H01L 2924/01078 : Platinum [Pt]H01L 2924/01079 : Gold [Au]H01L 2924/01082 : Lead [Pb]H01L 2924/01087 : Francium [Fr]H01L 2924/014 : Solder alloysH01L 2924/09701 : Low temperature co-fired ce...H01L 2924/10253 : Silicon [Si]H01L 2924/12042 : LASERH01L 2924/14 : Integrated circuitsH01L 2924/1433 : Application-specific integr...H01L 2924/15787 : Ceramics, e.g. crystalline ...H05K 2201/0367 : Metallic bump or raised con...H05K 2201/0373 : Conductors having a fine st...H05K 2201/10734 : Ball grid array [BGA]; Bump...H05K 3/325 : by abutting or pinching, i....H05K 3/4007 : Surface contacts, e.g. bump...Y10T 29/49147 : Assembling terminal to baseY10T 29/49155 : Manufacturing circuit on or...