Microelectronic assemblies having compliancy

• US 7,999,379 B2
• Filed: 02/23/2006
• Issued: 08/16/2011
• Est. Priority Date: 02/25/2005
• Status: Expired due to Fees

• Current Assignee: Tessera, Inc. (Adeia Inc.)
• Original Assignee: Tessera, Inc. (Adeia Inc.)
• Inventors: Haba, Belgacem
• Primary Examiner(s): Hoang; Quoc D
• Assistant Examiner(s): Tran; Tony
• Application Number:
  US11/360,230
• Publication Number:
  US 20060194365A1
• Time in Patent Office: 2,000 Days
• Field of Search: 257/737
• US Class Current: 257/737
• CPC Class Codes: G01R 31/2896 Testing of IC packages; Test features related to IC packages containers per se H01L23/02, encapsulations per se H01L23/28
• CPC Class Codes: H01L 2224/0231 Manufacturing methods of the redistribution layers
• CPC Class Codes: H01L 2224/0233 Structure of the redistribution layers
• CPC Class Codes: H01L 2224/0236 Shape of the insulating layers therebetween
• CPC Class Codes: H01L 2224/0239 Material of the redistribution layers
• CPC Class Codes: H01L 2224/024 Material of the insulating layers therebetween
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/0554 External layer
• CPC Class Codes: H01L 2224/1132 Screen printing, i.e. using a stencil
• CPC Class Codes: H01L 2224/1147 using a lift-off mask
• CPC Class Codes: H01L 2224/13016 in side view
• CPC Class Codes: H01L 2224/13023 the whole bump connector protruding from the surface
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/13147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/29099 Material
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 23/3114 the device being a chip scale package, e.g. CSP
• CPC Class Codes: H01L 23/3171 the coating being directly applied to the semiconductor body, e.g. passivation layer H01L23/3178 takes precedence
• CPC Class Codes: H01L 23/525 with adaptable interconnections
• 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 24/16 : of an individual bump connector
• CPC Class Codes: H01L 24/81 : using a bump connector
• CPC Class Codes: H01L 2924/00013 : Fully indexed content
• 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 2924/01022 : Titanium [Ti]
• 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 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01076 : Osmium [Os]
• 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 2924/014 : Solder alloys

Abstract

A microelectronic assembly includes a microelectronic element, such as a semiconductor wafer or semiconductor chip, having a first surface and contacts accessible at the first surface, and a compliant layer overlying the first surface of the microelectronic element, the compliant layer having openings in substantial alignment with the contacts of the microelectronic element. The assembly desirably includes conductive posts overlying the compliant layer and projecting away from the first surface of the microelectronic element, the conductive posts being electrically interconnected with the contacts of the microelectronic element by elongated, electrically conductive elements extending between the contacts and the conductive posts.

Claims

1. A microelectronic assembly comprising:

a microelectronic element having a first surface and contacts accessible at the first surface;

a compliant layer overlying a portion of the first surface of said microelectronic element, the compliant layer having a top surface remote from the first surface and a sloping transition surface extending away from the top surface, wherein at least a portion of at least one of the contacts is exposed beyond the sloping transition surface of the compliant layer;

conductive traces extending along the sloping transition surface and the top surface of said compliant layer, said traces connected with the contacts;

a plurality of substantially rigid metal posts overlying said compliant layer and projecting away from the first surface of said microelectronic element, said substantially rigid metal posts disposed remote from said contacts, each said substantially rigid metal post having a monolithic metal layer extending directly from a trace of said traces and extending above a height of said traces and to a majority of a height of such post, wherein said monolithic metal layer consists essentially of at least one metal selected from the group consisting of;

copper, copper alloys, gold and combinations thereof, and nickel, each said substantially rigid metal post having a base adjacent said compliant layer and a tip remote from said compliant layer, said base having a width along a surface of the compliant layer not greater than a width of any other portion of said substantially rigid metal post;

a solder mask overlying portions of the conductive traces, the solder mask having an exposed top surface and openings, wherein the substantially rigid metal posts extend through the openings to a height above the top surface of the solder mask; and

wherein said solder mask is a conformal layer such that a height of the to surface of the solder mask above the first surface of the microelectronic element varies with a shape of the compliant layer.

2. The assembly as claimed in claim 1, wherein said tips of said substantially rigid metal posts define the highest point on said assembly.

3. The assembly as claimed in claim 1, wherein said compliant layer has openings in substantial alignment with said contacts of said microelectronic element.

4. The assembly as claimed in claim 3, wherein said conductive traces pass through the openings in said compliant layer for conductively interconnecting said substantially rigid metal posts and said contacts of said microelectronic element.

5. The assembly as claimed in claim 1, wherein said microelectronic element is a semiconductor wafer.

6. The assembly as claimed in claim 1, wherein said microelectronic element is a semiconductor chip.

7. The assembly as claimed in claim 1, further comprising a dielectric passivation layer disposed between the first surface of said microelectronic element and said compliant layer.

8. The assembly as claimed in claim 1, wherein said compliant layer comprises a material having a low modulus of elasticity.

9. The assembly as claimed in claim 1, wherein said compliant layer comprises a dielectric material.

10. The assembly as claimed in claim 1, wherein said compliant layer comprises a material selected from the group consisting of silicones, flexibilized epoxies, polyimides, thermosetting polymers, fluoropolymers and thermoplastic polymers.

11. The assembly as claimed in claim 1, wherein said sloping transition surface extends between the top surface of said compliant layer and the first surface of said microelectronic element.

12. The assembly as claimed in claim 11, wherein the top surface of said compliant layer is substantially flat.

13. The assembly as claimed in claim 12, wherein the sloping transition surface includes at least one curved surface.

14. The assembly as claimed in claim 13, wherein the at least one curved surface includes a curved surface extending from the first surface of said microelectronic element.

15. The assembly as claimed in claim 13, wherein the at least one curved surface includes a curved surface extending from the top surface of said compliant layer.

16. The assembly as claimed in claim 1, wherein said conductive traces electrically interconnect said substantially rigid metal posts and said contacts of said microelectronic element.

17. The assembly as claimed in claim 1, wherein said traces comprise at least one material selected from the group consisting of copper, gold, nickel and alloys, combinations and composites thereof.

18. The assembly as claimed in claim 1, wherein said conductive traces extend over said compliant layer.

19. The assembly as claimed in claim 1, wherein said compliant layer comprises a plurality of compliant bumps overlying the first surface of said microelectronic element.

20. The assembly as claimed in claim 19, wherein at least one of said conductive posts is disposed atop at least one of said compliant bumps.

21. The assembly as claimed in claim 19, wherein said conductive posts are disposed atop said compliant bumps.

22. The assembly as claimed in claim 1, wherein each said substantially rigid metal post has a thickness of about 50-300 micrometers.

23. The assembly as claimed in claim 1, wherein at least one of said conductive posts has a frustoconical shape with the base having a diameter of about 100-600 micrometers and the tip having a diameter of about 40-200 micrometers.

24. The assembly as claimed in claim 1, wherein said monolithic metal layer consists essentially of at least one metal selected from the group consisting of:

copper and copper alloys.

25. The assembly as claimed in claim 1, wherein said monolithic metal layer consists essentially of a plated metal layer and is plated in contact with said trace.

26. The assembly as claimed in claim 1, wherein the tips of the substantially rigid metal posts have widths equal to the widths of the respective bases of the posts.

27. The assembly as claimed in claim 1, wherein the tip of at least one of the substantially rigid metal posts has a width equal to the width of the base of the at least one post.

28. The assembly as claimed in claim 1, wherein said monolithic metal layer has straight edges extending in an at least substantially vertical direction from said trace.

29. The assembly as claimed in claim 1, wherein edges of said monolithic metal layer extend in the vertical direction.

30. A microelectronic assembly comprising:

a microelectronic element having a first surface and contacts accessible at the first surface;

a compliant layer overlying a portion of the first surface of said microelectronic element, said compliant layer having a top surface spaced from the first surface of said microelectronic element and a sloping transition surface extending away from the top surface, wherein the first surface of the microelectronic element is exposed between at least one of the contacts and the sloping transition surface;

conductive posts overlying the top surface of said compliant layer and projecting away from the first surface of said microelectronic element, said conductive posts disposed remote from said contacts;

elongated, conductive elements electrically interconnecting said conductive posts and said contacts of said microelectronic element;

a solder mask overlying portions of the conductive elements, the solder mask having an exposed top surface and openings, wherein the conductive posts extend through the openings to a height above the top surface of the solder mask,

wherein each said conductive post has a monolithic metal layer extending directly from a conductive element of said conductive elements and extending above a height of said conductive elements and to a majority of a height of such post, wherein said monolithic metal layer consists essentially of at least one metal selected from the group consisting of;

copper, copper alloys, gold and combinations thereof, and nickel, and said monolithic metal layer consists essentially of a plated metal layer and is plated in contact with the conductive traces elements; and

wherein said solder mask is a conformal layer such that a height of the to surface of the solder mask above the first surface of the microelectronic element varies with a shape of the compliant layer.

31. The assembly as claimed in claim 30, wherein said microelectronic element is a semiconductor wafer.

32. The assembly as claimed in claim 30, wherein said microelectronic element is a semiconductor chip.

33. The assembly as claimed in claim 30, wherein said compliant layer comprises a plurality of compliant bumps and each said conductive post is disposed atop one of said conductive bumps.

34. The assembly as claimed in claim 30, wherein said compliant layer has openings in alignment with said contacts of said microelectronic element, said sloping transition surface of said compliant layer disposed in at least one of said openings and extending from the first surface of said microelectronic element to the top surface of said compliant layer, wherein said elongated, conductive elements overlie the sloping transition surface of said compliant layer.

35. The assembly as claimed in claim 30, wherein said monolithic metal layer consists essentially of at least one metal selected from the group consisting of:

copper and copper alloys.

36. The assembly as claimed in claim 30, wherein tips of the conductive posts remote from said compliant layer have widths equal to the widths of bases of the posts adjacent said compliant layer.

37. The assembly as claimed in claim 30, wherein a tip of at least one of the conductive posts remote from said compliant layer has a width equal to the width of a base of the at least one post adjacent said compliant layer.

38. The assembly as claimed in claim 30, wherein said monolithic metal layer has straight edges extending in an at least substantially vertical direction from the conductive element.

39. The assembly as claimed in claim 30, wherein edges of said monolithic metal layer extend in the vertical direction.

40. A microelectronic assembly comprising:

a microelectronic element having a first surface and contacts accessible at the first surface;

a compliant layer overlying a portion of the first surface of said microelectronic element, wherein the compliant layer does not wholly overlie at least one of the contacts;

conductive traces exposed at a top surface of said compliant layer, said traces connected with the contacts;

a dielectric layer overlying portions of the conductive traces, the dielectric layer having an exposed top surface and openings;

a plurality of substantially rigid metal posts overlying said compliant layer and projecting away from the first surface of said microelectronic element, said substantially rigid metal posts being directly in contact with said traces, each said substantially rigid metal post having a monolithic metal layer extending directly from a trace of said traces and extending above a height of said traces and to a majority of a height of such post, wherein said monolithic metal layer consists essentially of at least one metal selected from the group consisting of;

copper, copper alloys, gold and combinations thereof, and nickel,

wherein the substantially rigid metal posts extend through the openings to a height above the top surface of the dielectric layer; and

wherein said dielectric layer is a conformal layer such that a height of the to surface of the dielectric layer above the first surface of the microelectronic element varies with a shape of the compliant layer.

41. The assembly as claimed in claim 40, wherein said monolithic metal layer consists essentially of at least one metal selected from the group consisting of:

copper and copper alloys.

42. The assembly as claimed in claim 40, wherein said monolithic metal layer consists essentially of a plated metal layer and is plated in contact with said trace.

43. The assembly as claimed in claim 40, wherein tips of the substantially rigid metal posts remote from said compliant layer have widths equal to the widths of bases of the posts adjacent said compliant layer.

44. The assembly as claimed in claim 40, wherein a tip of at least one of the substantially rigid metal posts remote from said compliant layer has a width equal to the width of a base of the at least one post adjacent said compliant layer.

45. The assembly as claimed in claim 40, wherein said monolithic metal layer has straight edges extending in an at least substantially vertical direction from the trace.

46. The assembly as claimed in claim 40, wherein edges of said monolithic metal layer extend in the vertical direction.