Semiconductor copper bond pad surface protection

• US 20020135077A1
• Filed: 05/22/2002
• Published: 09/26/2002
• Est. Priority Date: 10/05/1998
• Status: Active Grant

• Current Assignee: Kulicke and Soffa Industries Incorporated
• Original Assignee: Kulicke and Soffa Industries Incorporated
• Inventors: Murdeshwar, Nikhil, Ellis, Timothy W., Eshelman, Mark A., Rheault, Christian
• Granted Patent: US 6,885,104 B2
• Time in Patent Office: Days
• US Class Current: 257/779
• CPC Class Codes: H01L 21/4846 Leads on or in insulating or insulated substrates, e.g. metallisation H01L21/4821 takes precedence; metallisation of ceramics in general C04B41/51; printed circuits H05K3/00
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05073 Single internal layer
• CPC Class Codes: H01L 2224/05647 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48647 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48699 Principal constituent of the connecting portion of the wire connector being Aluminium (Al)
• CPC Class Codes: H01L 2224/48747 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48847 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 23/49894 Materials of the insulating layers or coatings
• 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 24/45 of an individual wire connector
• 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01012 : Magnesium [Mg]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/0104 : Zirconium [Zr]
• CPC Class Codes: H01L 2924/01041 : Niobium [Nb]
• CPC Class Codes: H01L 2924/01057 : Lanthanum [La]
• CPC Class Codes: H01L 2924/01058 : Cerium [Ce]
• CPC Class Codes: H01L 2924/01073 : Tantalum [Ta]
• 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 2924/01105 : Rare earth metals
• CPC Class Codes: H01L 2924/01327 : Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/04941 : TiN
• CPC Class Codes: H01L 2924/04953 : TaN
• CPC Class Codes: H01L 2924/05042 : Si3N4
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/2075 : larger or equal to 1 micron less than 10 microns
• CPC Class Codes: H01L 2924/20753 : larger or equal to 30 microns less than 40 microns
• CPC Class Codes: H01L 2924/20754 : larger or equal to 40 microns less than 50 microns
• CPC Class Codes: H01L 2924/20755 : larger or equal to 50 microns less than 60 microns
• CPC Class Codes: H01L 2924/20756 : larger or equal to 60 microns less than 70 microns
• CPC Class Codes: H01L 2924/20757 : larger or equal to 70 microns less than 80 microns
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H05K 3/282 : for inhibiting the corrosion of the circuit, e.g. for preserving the solderability
• CPC Class Codes: Y10T 29/4913 : Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 428/24917 : including metal layer

Abstract

Electronic packages with uninsulated portions of copper circuits protected with coating layers having thicknesses that are suitable for soldering without fluxing and are sufficiently frangible when being joined to another metal surface to obtain metal-to-metal contact between the surfaces.

Claims

1. An electronic package comprising an uninsulated portion of a copper circuit protected with a coating layer consisting essentially of a ceramic material having a thickness that is suitable for soldering without fluxing and that is sufficiently frangible when being joined to another metal surface to obtain metal-to-metal contact between the surfaces.

2. The package of claim 1, wherein said ceramic material is selected from the group consisting of hydrides of rare earth-copper complexes, hydrides of hydride-forming copper-immiscible metals, silicon nitride, silicon carbide, titanium nitride, tantalum nitride, aluminum oxide, magnesium oxide, silicon dioxide, titanium, dioxide, zirconium oxide, tantalum carbide, tungsten carbide, titanium carbide, boron carbide, cubic boron nitride and diamond.

3. The package of claim 1, wherein said thickness of said layer of ceramic material provides said layer with a Rockwell Hardness (N-45) value greater than about 38.

4. The package of claim 1, wherein said layer has a thickness between about 10 and about 1,000 angstroms.

5. The package of claim 1, comprising a semiconductor wafer including at least one device having an uninsulated copper bond pad protected with said coating layer, wherein said coating layer is sufficiently frangible during ball or wedge wire bonding to obtain metal-to-metal contact between each bonding surface and the wire bonded thereto.

6. The wafer of claim 5, further comprising at least one wire that is ball or wedge bonded to said bond pad of said wafer device.

7. The wafer of claim 5, wherein said device is a flip chip in which at least one wire lead is soldered to said coated bond pad.

8. The package of claim 1, wherein said package comprises an organic substrate package, a metal substrate package or a ceramic substrate package

9. An electronic package comprising an uninsulated portion of a copper circuit coated with a surface layer of a material selected from the group consisting of copper-rare earth metal complexes and copper-immiscible metals that form metal hydride compounds, said surface layer having a thickness that, upon exposure to a reducing environment containing hydrogen, forms a hydride layer having a thickness that is suitable for soldering without fluxing and that provides the layer with a hardness that is sufficiently frangible when being joined to another metal surface to obtain metal-to-metal contact between the surfaces.

10. The package of claim 9, wherein said surface layer comprises a copper-immiscible metal.

11. The package of claim 10, wherein said surface layer is formed by co-deposition of said copper-immiscible metal and copper to form said bond pad during wafer fabrication, followed by heating of said wafer so that said copper-immiscible metal migrates to said bond pad surface, thereby forming said surface layer.

12. The package of claim 11, wherein said surface layer is formed by vapor, electro-chemical deposition of said copper-immiscible metal onto said bond surface.

13. The package of claim 9, wherein said surface layer consists essentially of a copper-rare earth metal complex.

14. The package of claim 13, wherein said copper complex is formed by vapor deposition, electrodeposition or chemical deposition of said rare earth metal in a layer onto said bond pad surface.

15. The package of claim 14, wherein said copper complex forms by heating said deposited rare earth metal layer.

16. The package of claim 13, wherein said rare earth metal is selected from the group consisting of La, Y and Ce.

17. The package of claim 9, wherein said copper-immiscible metal is selected from the group consisting of Ta, V and Nb.

18. The package of claim 9, wherein said package comprises aan organic substrate package, a metal substrate package or a ceramic substrate package

19. The package of claim 9, comprising a semiconductor wafer including at least one device having an uninsulated copper bond pad.

20. An electronic package comprising an uninsulated portion of a copper circuit coated with a surface layer of a rare earth metal that forms a copper complex, said surface layer having a thickness that, upon formation of said copper complex and exposure to a reducing environment comprising hydrogen, forms a hydride layer having a thickness that is suitable for soldering without fluxing and that is sufficiently frangible when being joined to another metal surface to obtain metal-to-metal contact between the surfaces.

21. The package of claim 20, wherein said surface layer is formed by vapor deposition, electrodeposition or chemical deposition of said rare earth metal in a layer on said bond pad surface.

22. The package of claim 20, wherein said rare earth metal is selected from the group consisting of La, Y and Ce.

23. The package of claim 20, wherein said package comprises an organic substrate package, a metal substrate package or a ceramic substrate package

24. The package of claim 20, comprising a semiconductor wafer including at least one device having an uninsulated copper bond pad.

26. The package of claim 25, wherein said surface layer comprises a hydride of a copper-immiscible metal.

27. The package of claim 26, wherein said copper-immiscible metal is selected from the group consisting of Ta, V and Nb.

28. The package of claim 25, wherein said surface layer consists essentially of a hydride of a copper-rare earth metal complex.

29. The package of claim 25, wherein said rare earth metal is selected from the group consisting of La, Y and Ce.

30. The package of claim 25, wherein said package comprises an organic substrate package, a metal substrate package or a ceramic substrate package 31. The package of claim 25, comprising a semiconductor wafer including at least one device having an uninsulated copper bond pad coated with a surface layer that is sufficiently frangible during ball or wedge wire bonding to obtain metal-to-metal contact between each bonding surface and the wire bonded thereto.

25. An electronic package comprising an uninsulated portion of a copper circuit coated with a surface layer of a metal hydride compound selected from the group consisting of metal hydrides of copper-rare earth metal complexes and metal hydrides of copper-immiscible metals that form metal hydrides, said surface layer having a thickness that is suitable for soldering without fluxing and that is sufficiently frangible when being joined to another metal surface to obtain metal-to-metal contact between the surfaces.