Wafer-level interconnect for high mechanical reliability applications

• US 8,754,524 B2
• Filed: 02/16/2012
• Issued: 06/17/2014
• Est. Priority Date: 10/05/2006
• Status: Active Grant

• Current Assignee: Huatian Technology (Kunshan) Electronics Co., Ltd
• Original Assignee: Flipchip International LLC (Tianshui Huatian Technology Company Limited)
• Inventors: Curtis, Anthony, Burgess, Guy F., Johnson, Michael, Tessier, Ted, Lu, Yuan
• Primary Examiner(s): CLARK, JASMINE JHIHAN B
• Application Number:
  US13/397,876
• Publication Number:
  US 20120146219A1
• Time in Patent Office: 852 Days
• Field of Search: 257/772, 257/779, 257/E23.015, 257/E23.02, 257E23023-E23079, 257/E21.508, 257/E21.509, 257/E21.519
• US Class Current: 257/738
• CPC Class Codes: B23K 2101/36 Electric or electronic devices
• CPC Class Codes: B23K 35/262 Sn as the principal constituent
• CPC Class Codes: C22C 13/00 Alloys based on tin
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/05124 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05155 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05164 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/05166 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/05171 Chromium [Cr] as principal constituent
• CPC Class Codes: H01L 2224/0558 being stacked
• 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 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/131 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 24/03 Manufacturing methods
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 24/10 Bump connectors bumps on insulating substrates, e.g. chip carriers, H01L23/49816; Manufacturing methods related thereto
• 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 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 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• 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 2924/01074 : 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 2924/01327 : Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H05K 3/3463 : Solder compositions in relation to features of the printed circuit board or the mounting process

Abstract

An interconnect structure comprises a solder including nickel (Ni) in a range of 0.01 to 0.20 percent by weight. The interconnect structure further includes an intermetallic compound (IMC) layer in contact with the solder. The IMC layer comprises a compound of copper and nickel.

Claims

1. An interconnect structure positioned between two electrical contacts including a first metal contact and a second metal contact, the interconnect structure comprising:

a solder alloy comprising nickel (Ni) and tin (Sn), wherein the nickel (Ni) is in a range of 0.01 to 0.20 percent by weight (wt %); and

an intermetallic compound (IMC) layer having a top surface in contact with the solder alloy and a bottom surface in contact with the first metal contact, the IMC layer comprising a compound of copper and nickel.

2. The interconnect structure of claim 1, wherein the interconnect structure is incorporated in a flip-chip package.

3. The interconnect structure of claim 1, wherein the first metal contact comprises nickel.

4. The interconnect structure of claim 1, wherein the solder alloy consists essentially of nickel (Ni), tin (Sn), silver (Ag), and copper (Cu).

5. The interconnect structure of claim 1, wherein the first metal contact and the second metal contact are each located on a respective substrate, and the respective substrate of the first metal contact is a semiconductor die comprising an integrated circuit electrically coupled to the second metal contact.

6. The interconnect structure of claim 1, wherein the first metal contact comprises a top layer comprising copper.

7. The interconnect structure of claim 6, wherein the first metal contact further comprises an intermediate layer underlying the top layer, and the intermediate layer comprises nickel.

8. The interconnect structure of claim 1, wherein the compound of copper and nickel promotes smoothness of the top surface of the IMC layer.

9. An interconnect structure, comprising:

a semiconductor substrate comprising an integrated circuit;

an under bump metallurgy (UBM) on the substrate, the UBM comprising nickel and the integrated circuit electrically coupled to the UBM;

an intermetallic compound (IMC) layer on the UBM, the IMC layer comprising a compound of copper and nickel; and

a bulk solder body on the IMC layer, the bulk solder body comprising nickel (Ni) and copper (Cu), wherein the nickel (Ni) is in a range of 0.01 to 0.20 percent by weight (wt %).

10. The interconnect structure of claim 9, wherein the bulk solder body comprises:

greater than 94.5 percent by weight (wt %) tin (Sn);

less than 4.0 percent by weight (wt %) silver (Ag); and

less than 2.0 percent by weight (wt %) copper (Cu).

11. The interconnect structure of claim 9, wherein the bulk solder body comprises less than 2.0 percent by weight (wt %) of copper (Cu).

12. The interconnect structure of claim 9, wherein the under bump metallurgy (UBM) is a film having a top layer of copper and an underlying layer of nickel.

13. The interconnect structure of claim 9, wherein the IMC layer has a thickness of less than 2.0 microns.

14. The interconnect structure of claim 9, wherein the under bump metallurgy (UBM) is a film composed of one or more alloys selected from the group consisting of:

aluminum (Al)-nickel vanadium (NiV)-copper (Cu);

titanium (Ti)-nickel vanadium (NiV)-copper (Cu);

titanium (Ti)-nickel (Ni)-copper (Cu);

titanium tungsten (TiW)-copper (Cu);

titanium tungsten (TiW)-nickel (Ni)-copper (Cu);

titanium tungsten (TiW)-nickel vanadium (NiV)-copper (Cu);

chromium (Cr)-nickel (Ni)-copper (Cu); and

chromium (Cr)-nickel vanadium (NiV)-copper (Cu).

15. The interconnect structure of claim 9, wherein the UBM has a structure selected from the group consisting of:

aluminum (Al)-nickel vanadium (NiV)-copper (Cu); and

titanium (Ti)-nickel vanadium (NiV)-copper (Cu).

16. An interconnect structure positioned between two electrical contacts, the interconnect structure comprising:

a solder alloy attached through an intermetallic compound (IMC) layer to an under bump metallurgy containing copper on a top surface, the under bump metallurgy being disposed between the two contacts, and the solder alloy comprising nickel (Ni), tin (Sn), silver (Ag), and copper (Cu);

wherein the nickel (Ni) content is in a range of 0.01 to 0.20 percent by weight (wt %), and the IMC layer comprises a compound of copper and nickel.