Interconnect structure having improved metallization

• US 5,436,412 A
• Filed: 08/03/1993
• Issued: 07/25/1995
• Est. Priority Date: 10/30/1992
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Perfecto, Eric D., Kumar, Ananda H., Ahmad, Umar M. U., Purushothaman, Sampath, Ray, Sudipta K., Prasad, Chandrika
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): TSO, LAURA K
• Application Number:
  US08/102,027
• Time in Patent Office: 721 Days
• Field of Search: 174/250, 174/251, 174/255, 174/257, 174/261, 174/262, 174/265
• US Class Current: 174/265
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 23/49816 Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 23/49866 characterised by the materials materials of the substrates H01L23/14, of the lead-frames H01L23/49579
• CPC Class Codes: H01L 23/5383 Multilayer substrates H01L23/5385 takes precedence; multilayer metallisation on monolayer substrates H01L23/538
• CPC Class Codes: H01L 24/48 of an individual wire connector
• 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 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H05K 1/0306 Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: H05K 1/113 Via provided in pad; Pad over filled via
• CPC Class Codes: H05K 2201/0154 Polyimide
• CPC Class Codes: H05K 2201/0195 Dielectric or adhesive layers comprising a plurality of layers, e.g. in a multilayer structure
• CPC Class Codes: H05K 2201/09563 Metal filled via plated through-hole filled with insulating material H05K2201/0959
• CPC Class Codes: H05K 2201/096 : Vertically aligned vias, holes or stacked vias
• CPC Class Codes: H05K 2201/0979 : Redundant conductors or connections, i.e. more than one current path between two points
• CPC Class Codes: H05K 3/0041 : by plasma etching
• CPC Class Codes: H05K 3/4076 : by thin-film techniques
• CPC Class Codes: H05K 3/4605 : made from inorganic insulating material
• CPC Class Codes: H05K 3/467 : Adding a circuit layer by thin film methods H05K3/4647 takes precedence

Abstract

An electrical interconnect structure for connecting a substrate to the next level of packaging or to a semiconductor device. The interconnect structure includes at least two layers of polymeric material, one of the layers having a capture pad and the second of the layers having a bonding pad electrically connected to the capture pad. The bonding pad and the second layer of polymeric material are at the same height so that the bonding pad is level with the second layer of polymeric material. Finally, there is a cap of electrically conducting metallization on the bonding pad and extending beyond the second layer of polymeric material. The cap is of a different composition than the bonding pad.

Claims

1. An electrical interconnect structure comprising:

at least one electrically conducting feature on a surface of a substrate;

a cap of electrically conducting metallization on the electrically conducting feature wherein said cap only partially covers said electrically conducting feature; and

a layer of polymeric material deposited on the surface of the substrate, on the electrically conducting feature not covered by said cap and around said cap, wherein said cap extends beyond the layer of polymeric material.

2. The interconnect structure of claim 1 further comprising at least a second electrically conducting feature, said second electrically conducting feature being totally enclosed within said layer of polymeric material.

3. The interconnect structure of claim 1 wherein the electrically conducting feature is a pad for joining to a semiconductor device.

4. The interconnect structure of claim 1 wherein the electrically conducting feature is selected from the group consisting of an engineering change and a wiring bonding pad.

5. The interconnect structure of claim 1 wherein said electrically conducting feature is a bonding pad for receiving an I/O pin or pad.

6. The interconnect structure of claim 1 wherein the cap of metallization is selected from the group consisting of sequential layers of nickel (P) and gold and cobalt (P) and gold.

7. The interconnect structure of claim 1 wherein the cap of metallization is selected from the group consisting of sequential layers of Cr/Cu/Ti/Mo/Au, Cr/Ni/Au, Cr/Ti/Au, Cr/Co/Au, Cr/Cu/Ni/Au and Cr/Cu/Co/Au.

8. An electrical interconnect structure comprising:

at least one electrically conducting capture pad on a surface of the substrate;

a first layer of polymeric material deposited on the surface of the substrate and the capture pad;

at least one electrically conducting bonding pad deposited on the first layer of polymeric material;

an electrically conducting stud connecting the capture pad and bonding pad through said first layer of polymeric material;

a second layer of polymeric material deposited on the first layer of polymeric material and around the bonding pad, the polymeric material being at the same height as the bonding pad;

a cap of electrically conducting metallization on the bonding pad extending beyond the second layer of polymeric material, the cap being of a different composition than the bonding pad; and

further comprising a third layer of polymeric material deposited on the second layer of polymeric material and around the cap of metallization, the cap of metallization extending beyond the third layer of polymeric material.

9. The interconnect structure of claim 8 further comprising a wiring line enclosed within said first layer of polymeric material.

10. The interconnect structure of claim 8 further comprising a wiring line enclosed within said second layer of polymeric materials.

11. The interconnect structure of claim 8 wherein there are a plurality of capture pads and bonding pads.

14. The interconnect structure of claim 11 further comprising at least one pad external to the substrate bonded to a cap of metallization on a bonding pad to form a pad-on-pad connection.

15. The interconnect structure of claim 14 further comprising at least one I/O pin bonded to a cap of metallization on a bonding pad to form a pin connection.

12. An electrical interconnect structure comprising:

at least one electrically conducting capture pad on a surface of the substrate;

a first layer of polymeric material deposited on the surface of the substrate and the capture pad;

at least one electrically conducting bonding pad deposited on the first layer of polymeric material;

an electrically conducting stud connecting the capture pad and bonding pad through said first layer of polymeric material;

a second layer of polymeric material deposited on the first layer of polymeric material and around the bonding pad, the polymeric material being at the same height as the bonding pad;

a cap of electrically conducting metallization on the bonding pad extending beyond the second layer of polymeric material, the cap being of a different composition than the bonding pad;

wherein the bonding pads are principally copper; and

wherein the cap of metallization is selected from the group consisting of sequential layers of nickel(P) and gold and cobalt(P) and gold.

13. An electrical interconnect structure comprising:

at least one electrically conducting capture pad on a surface of the substrate;

a first layer of polymeric material deposited on the surface of the substrate and the capture pad;

at least one electrically conducting bonding pad deposited on the first layer of polymeric material;

an electrically conducting stud connecting the capture pad and bonding pad through said first layer of polymeric material;

a second layer of polymeric material deposited on the first layer of polymeric material and around the bonding pad, the polymeric material being at the same height as the bonding pad;

a cap of electrically conducting metallization on the bonding pad extending beyond the second layer of polymeric material, the cap being of a different composition than the bonding pad;

wherein the bonding pads are principally copper; and

wherein the cap of metallization is selected from the group consisting of sequential layers of Cr/Cu/Ti/Mo/Au, Cr/Ni/Au, Cr/Ti/Au, Cr/Co/Au, Cr/Cu/Ni/Au and Cr/Cu/Co/Au.

16. An electrical interconnect structure comprising:

at least two electrically conducting capture pads on a surface of the substrate;

a first layer of polymeric material deposited on the surface of the substrate and the capture pads;

at least two electrically conducting bonding pads deposited on the first layer of polymeric material wherein one bonding pad is larger than the other bonding pad;

an electrically conducting stud connecting each of the capture pads to a corresponding bonding pad through said first layer of polymeric material;

a second layer of polymeric material deposited on the first layer of polymeric material and around the bonding pads, the polymeric material being at the same height as the bonding pads;

a cap of electrically conducting metallization on each of the bonding pads extending beyond the second layer of polymeric material, the caps of metallization being of a different composition than the bonding pads.

17. The interconnect structure of claim 16 further comprising a third layer of polymeric material deposited on the second layer of polymeric material and around the caps of metallization, the caps of metallization extending beyond the third layer of polymeric material.

18. The interconnect structure of claim 16 further comprising a wiring line enclosed within said first layer of polymeric material.

19. The interconnect structure of claim 16 further comprising a wiring line enclosed within said second layer of polymeric material.

20. The interconnect structure of claim 16 wherein the bonding pads are principally copper.

21. The interconnect structure of claim 16 wherein the caps of metallization are selected from the group consisting of sequential layers of nickel(P) and gold and cobalt(P) and gold.

22. The interconnect structure of claim 17 wherein the bonding pads are principally copper.

23. The interconnect structure of claim 22 wherein the caps of metallization are selected from the group consisting of sequential layers of Cr/Cu/Ti/Mo/Au, Cr/Ni/Au, Cr/Ti/Au, Cr/Cu/Ni/Au and Cr/Cu/Co/Au.

24. The interconnect structure of claim 16 further comprising at least one pad external to the substrate bonded to the smaller of the bonding pads and the cap of metallization to form a pad-on-pad connection.

25. The interconnect structure of claim 24 further comprising at least one I/O pin bonded to the larger of the bonding pads and the cap of metallization to form a pin connection.

26. The interconnect structure of claim 16 wherein there are a plurality of capture pads and a plurality of the differently-sized bonding pads.

27. The interconnect structure of claim 26 further comprising a plurality of pads external to the substrate bonded to the smaller of the bonding pads and the caps of metallization and to form a plurality of pad-on-pad connections.

28. The interconnect structure of claim 27 further comprising a plurality of I/O pins bonded to the larger of the bonding pads and the caps of metallization to form a plurality of pin connections.

29. The interconnect structure of claim 28 wherein the plurality of pad-on-pad connections are located around the periphery of the surface of the substrate and the plurality of pin connections are located in a generally central portion of the surface of the substrate.

30. The interconnect structure of claim 16 wherein there are a plurality of electrically conducting studs connecting at least one capture pad to its corresponding bonding pad.