MULTILAYER PILLAR FOR REDUCED STRESS INTERCONNECT AND METHOD OF MAKING SAME

• US 20190326242A1
• Filed: 07/03/2019
• Published: 10/24/2019
• Est. Priority Date: 10/11/2007
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: JADHAV, Virendra R., SEMKOW, Krystyna W., SRIVASTAVA, Kamalesh K., SUNDLOF, Brian R.
• Granted Patent: US 11,094,657 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/05099 Material
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/05666 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/1145 Physical vapour deposition [PVD], e.g. evaporation, or sputtering
• CPC Class Codes: H01L 2224/11452 Chemical vapour deposition [CVD], e.g. laser CVD
• CPC Class Codes: H01L 2224/11462 Electroplating
• CPC Class Codes: H01L 2224/11901 with repetition of the same manufacturing step
• CPC Class Codes: H01L 2224/13005 Structure
• CPC Class Codes: H01L 2224/13013 being rectangular or square
• CPC Class Codes: H01L 2224/13023 the whole bump connector protruding from the surface
• CPC Class Codes: H01L 2224/1308 being stacked
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/13109 Indium [In] as principal constituent
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/13113 Bismuth [Bi] as principal constituent
• CPC Class Codes: H01L 2224/13124 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/13139 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/13144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/13147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/13155 : Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/13166 : Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/13171 : Chromium [Cr] as principal constituent
• CPC Class Codes: H01L 2224/13184 : Tungsten [W] as principal constituent
• CPC Class Codes: H01L 2224/13599 : Material
• CPC Class Codes: H01L 2224/13655 : Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/13666 : Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/13671 : Chromium [Cr] as principal constituent
• CPC Class Codes: H01L 2224/13684 : Tungsten [W] as principal constituent
• CPC Class Codes: H01L 2224/16235 : the bump connector connecting to a via metallisation of the item
• CPC Class Codes: H01L 2224/29099 : Material
• CPC Class Codes: H01L 2224/29599 : Material
• CPC Class Codes: H01L 2224/81815 : Reflow soldering
• CPC Class Codes: H01L 23/562 : Protection against mechanical damage H01L23/02, H01L23/28 take precedence
• 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 2924/00014 : 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 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01024 : Chromium [Cr]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• 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 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/2064 : larger or equal to 1 micron less than 100 microns
• CPC Class Codes: H01L 2924/351 : Thermal stress
• CPC Class Codes: H01L 2924/35121 : Peeling or delaminating
• CPC Class Codes: H01L 2924/37001 : Yield
• CPC Class Codes: H01L 2924/384 : Bump effects
• CPC Class Codes: Y10T 156/10 : Methods of surface bonding and/or assembly therefor

Abstract

A multi-layer pillar and method of fabricating the same is provided. The multi-layer pillar is used as an interconnect between a chip and substrate. The pillar has at least one low strength, high ductility deformation region configured to absorb force imposed during chip assembly and thermal excursions

Claims

1. A method comprising:

forming a barrier and adhesion layer that connects a modulated copper pillar to a chip;

forming a seed layer contacting the barrier and adhesion layer;

forming a first copper layer contacting the seed layer;

forming a second copper layer contacting a solder material;

forming at least one deformation region having a modulus of elasticity less than copper between the first copper layer and the second copper layer; and

forming protective layers interposed at interfaces between a surface of the at least one deformation region and the first copper layer and the surface of the at least one deformation region and the second copper layer.

2. The method of claim 1, wherein the at least one deformation region comprises two separate low strength, high ductility deformation regions between the first copper layer and the second copper layer.

3. The method of claim 2, further comprising forming a third copper layer between the two separate low strength, high ductility deformation regions.

4. The method of claim 3, wherein at least one low strength, high ductility deformation region of the two separate low strength, high ductility deformation regions includes at least one material of gold, aluminum and silver.

5. The method of claim 4, wherein the at least one low strength, high ductility deformation region is about 0.2 to 1 microns in thickness.

6. The method of claim 5, wherein a first protective layer of the protective layers is interposed at an interface between an uppermost surface of the at least one low strength, high ductility deformation region and the first copper layer, and a second protective layer of the protective layers is interposed at an interface between a lowermost surface of the at least one low strength, high ductility deformation region and the second copper layer.

7. The method of claim 6, wherein the first protective layer is a layer of nickel covering the entire uppermost surface of the at least one low strength, high ductility deformation region, and the second protective layer is another layer of nickel covering the entire lowermost most surface of the at least one low strength, high ductility deformation region.

8. The method of claim 1, wherein the barrier and adhesion layer prevents a diffusion of materials between the chip and materials of the modulated copper pillar.

9. The method of claim 1, wherein the solder material contacts a via in a substrate.

10. The method of claim 1, wherein a vertical sidewall of the first copper layer is aligned with a vertical sidewall of the second copper layer.

11. The method of claim 1, wherein the protective layers are layers of nickel covering an entire surface of the at least one deformation region.