Electroless process for the preparation of particle enhanced electric contact surfaces

• US 6,630,203 B2
• Filed: 06/15/2001
• Issued: 10/07/2003
• Est. Priority Date: 06/15/2001
• Status: Expired due to Fees

• Current Assignee: Bio Lab Naturals, Inc. (Limitless X Holdings, Inc.)
• Original Assignee: Bio Lab Naturals, Inc. (Limitless X Holdings, Inc.)
• Inventors: Zou, Bin, Neuhaus, Herbert J., Blum, Fred A., Bahn, Robert J.
• Primary Examiner(s): BARR, MICHAEL E
• Application Number:
  US09/883,012
• Publication Number:
  US 20020192363A1
• Time in Patent Office: 844 Days
• Field of Search: 427/98, 427/123, 427/304, 427/305, 427/437, 427/438, 427/443.1
• US Class Current: 427/304
• CPC Class Codes: G06K 19/0775 arrangements for connecting the integrated circuit to the antenna
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/83101 as prepeg comprising a layer connector, e.g. provided in an insulating plate member
• CPC Class Codes: H01L 2224/8319 Arrangement of the layer connectors prior to mounting
• CPC Class Codes: H01L 2224/838 Bonding techniques
• CPC Class Codes: H01L 23/49811 Additional leads joined to the metallisation on the insulating substrate, e.g. pins, bumps, wires, flat leads H01L23/49827 takes precedence
• 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 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/83 using a layer 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01011 Sodium [Na]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01025 Manganese [Mn]
• 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 2924/01037 : Rubidium [Rb]
• CPC Class Codes: H01L 2924/01044 : Ruthenium [Ru]
• CPC Class Codes: H01L 2924/01045 : Rhodium [Rh]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• 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 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/0781 : being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H05K 3/4007 : Surface contacts, e.g. bumps H05K3/4092 takes precedence; deposition of finish layers on pads H05K3/24; forming solder bumps H05K3/3457
• CPC Class Codes: Y10T 428/12451 : Macroscopically anomalous interface between layers
• CPC Class Codes: Y10T 428/12486 : Laterally noncoextensive components [e.g., embedded, etc.]

Abstract

The present invention provides a unique method for the electroless co-deposition of metal and hard particles on an electrical contact surface to provide electrical, thermal, and mechanical connections between the particle enhanced contact surface and an opposing contact surface, and to enhance the thermal and electrical conductivity between the contact surfaces and their corresponding substrates. The innovative method is able to uniformly deposit metal and particles of any shape, and with a wide range of density and sizes, on contact surfaces, and can be adjusted to provide any desired surface area coverage in desirable deposition patterns. The co-deposited contact surface can, for example, be easily joined to another surface of any type by nonconductive adhesive, resulting in a connection that is mechanically robust, chemically inert, and inherently electrically conductive.

Claims

1. A method for enhancing at least one electrical contact surface to provide an improved electrical, thermal, and/or mechanical connection with at least one opposing electrical contact surface, the method comprising:

co-depositing a first layer of a first metal and at least one particle on the at least one electrical contact surface by electroless deposition, wherein the at least one particle is trapped by the deposition of the first metal on the at least one electrical contact surface;

activating the at least one particle to accept a deposition of a second layer of a second metal; and

depositing the second layer of the second metal over the at least one particle by electroless deposition.

2. A method as described in claim 1 wherein the at least one particle comprises a plurality of particles.

3. A method as described in claim 1 further comprising depositing a layer of gold over the second layer of the second metal.

4. A method as described in claim 3 wherein the gold is deposited by an immersion gold process.

5. A method as described in claim 1 wherein the first metal comprises at least one of the following substances:

nickel, cobalt, copper, iron, gold, silver, zinc, palladium, platinum, rhodium, and ruthenium.

6. A method as described in claim 1 wherein the second metal comprises at least one of the following substances:

nickel, cobalt, copper, iron, gold, silver, zinc, palladium, platinum, rhodium, and ruthenium.

7. A method as described in claim 1 wherein the second metal comprises the same metal as the first metal.

8. A method as described in claim 1 wherein the at least one particle is a nonconductive particle comprising at least one of the following substances:

ceramics, glasses, metals, oxides, silicates, suicides, borides, nitrides, and diamonds.

9. A method as described in claim 1 or claim 8 wherein the at least one particle comprises a hard particle capable of piercing the electrical contact surface.

10. A method as described in claim 1 or claim 8 wherein the at least one particle comprises a hard particle capable of piercing the opposing electrical contact surface.

11. A method as described in claim 1 wherein the at least one electrical contact surface comprises a contact pad of an integrated circuit chip.

12. A method as described in claim 1 wherein the at least one electrical contact surface comprises a plurality of discrete electrical contact surfaces.

13. A method as described in claim 12 wherein the surfaces of the plurality of discrete electrical contact surfaces are electrically insulated from each other.

14. A method as described in claim 12 wherein the plurality of discrete electrical contact surfaces comprises an area array contact configuration of an integrated circuit chip.

15. A method as described in claim 12 wherein the plurality of discrete electrical contact surfaces comprises a plurality of contact surfaces on an integrated circuit wafer.

16. A method as described in claim 1 wherein the at least one particle comprises a plurality of particles and the step of co-depositing comprises depositing the plurality of particles in a single, uniformly dispersed layer on the at least one contact surface.

17. A method for enhancing an electrical contact surface to provide an improved electrical, thermal, and/or mechanical connection with an opposing electrical contact surface, the method comprising:

co-depositing a first layer of nickel and a plurality of diamond particles on the electrical contact surface by electroless deposition, wherein the plurality of diamond particles is deposited in a single, uniformly dispersed layer, and the plurality of diamond particles is trapped by the deposition of the first layer of nickel on the electrical contact surface;

activating the plurality of diamond particles to accept a deposition of a second layer of nickel; and

depositing the second layer of nickel over the plurality of diamond particles by electroless deposition.

18. A method as described in claim 17 further comprising depositing a layer of immersion gold over the second layer of nickel.

19. A method as described in claim 17, wherein the electrical contact surface comprises a contact pad of an integrated circuit chip.

20. A method as described in claim 19 wherein the contact pad is one of a plurality of contact pads of the integrated circuit chip and the contact pad is electrically isolated from any other of the plurality of contact pads of the integrated circuit chip.