IP Library › Granted Patent US 7,186,923
Granted Patent B2
US 7,186,923 · App. 10/728,423 · Granted Mar 6, 2007

Printed wiring boards and methods for making them

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Quick Facts
Patent No.
US 7,186,923
App. No.
10/728,423
Granted
Mar 6, 2007
Kind
B2
Abstract

A printed wiring board comprising conductive layers separated by nonconductive material and having through holes or other nonconductive surfaces on which an electrically conductive carbon coating is formed. The conductive carbon coating includes electrically conductive carbon having a mean particle size not greater than about 1 micron and a water-dispersible organic binding agent. The conductive carbon coating formed on the nonconductive surfaces has a low electrical resistance and is tenacious enough to be plated and exposed to molten solder without creating voids or losing adhesion.

Claims (23)

1. A printed wiring board comprising:

A. at least two conductive circuit layers separated by nonconductive material;

B. at least one recess in said nonconductive material defined by a nonconductive surface intersecting at least two of said conductive circuit layers, said at least one recess having a diameter within the range of about 0.15 mm to about 6 mm;

C. an electrically conductive coating adhered to said nonconductive surface defining said recess, said coating including electrically conductive carbon having a mean particle size no greater than about 1 micron and a water-dispersible organic binding agent, wherein said coating is electrically conductive, thereby allowing electrical current to flow between the two conductive circuit layers such that the electrically conductive coating can accept electroplating to provide a surface at least substantially free of visible voids.

2. The printed wiring board of claim 1 , having a resistivity between said conductive circuit layers of less than about 1000 ohms prior to electroplating.

3. The printed wiring board of claim 1 , having a resistivity between said conductive circuit layers of less than about 600 ohms, prior to electroplating.

4. The printed wiring board of claim 1 , having a resistivity between said conductive circuit layers of less than about 400 ohms, prior to electroplating.

5. The printed wiring board of claim 1 , having a resistivity between said conductive circuit layers of less than about 250 ohms, prior to electroplating.

6. The printed wiring board of claim 1 , having a resistivity between said conductive circuit layers of less than about 80 ohms, prior to electroplating.

7. The printed wiring board of claim 1 , having a resistivity of less than about 60 ohms between said conductive circuit layers, prior to electroplating.

8. The printed wiring board of claim 1 , having a resistivity between said conductive circuit layers of less than about 30 ohms, prior to electroplating.

9. The printed wiring board of claim 1 , having a resistivity between said conductive circuit layers of less than about 10 ohms, prior to electroplating.

10. The printed wiring board of claim 1 , having a resistivity between said conductive circuit layers of less than about 2 ohms, prior to electroplating.

11. The printed wiring board of claim 1 , including a multiplicity of said conductive through holes including said coating.

12. The printed wiring board of claim 1 , wherein said coating is not greater than about 12 microns thick.

13. The printed wiring board of claim 1 , wherein said coating is not greater than about 7 microns thick.

14. The printed wiring board of claim 1 , wherein said coating is not greater than about three microns thick.

15. The printed wiring board of claim 1 , wherein said coating is not greater than about one micron thick.

16. The printed wiring board of claim 1 , wherein said coating is free of lumpiness.

17. The printed wiring board of claim 1 , wherein said water-dispersible organic binding agent is selected from the group consisting of monosaccharides, polysaccharides, and combinations thereof.

18. The printed wiring board of claim 1 , wherein said electrically conductive carbon comprises graphite.

19. The printed wiring board of claim 1 , further comprising an electroplated layer deposited on at least a portion of said electrically conductive coating.

20. The printed wiring board of claim 19 , further comprising a solder layer deposited on at least a portion of said electroplated layer.

Assignments (8)
TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENTS Recorded Oct 28, 2015
From: PNC BANK
To: OMG ELECTRONIC CHEMICALS, LLC
Reel/Frame 036985/0566 →
SECURITY AGREEMENT Recorded Sep 12, 2013
From: OM GROUP, INC.; OMG ELECTRONIC CHEMICALS, LLC; OMG AMERICAS, INC.; EAGLEPICHER TECHNOLOGIES, LLC; EAGLEPICHER MEDICAL POWER, LLC
To: PNC BANK
Reel/Frame 031208/0876 →
RELEASE OF SECURITY INTEREST Recorded Sep 5, 2013
From: BANK OF AMERICA, N.A.
To: OM GROUP, INC.; EAGLEPICHER TECHNOLOGIES, LLC; EAGLEPICHER MEDICAL POWER, LLC; OMG AMERICAS, INC.; OMG ELECTRONIC CHEMICALS, LLC
Reel/Frame 031169/0976 →
SECURITY AGREEMENT Recorded Aug 12, 2011
From: OM GROUP, INC., A DELAWARE CORPORATION; COMPUGRAPHICS U.S.A. INC., A DELAWARE CORPORATION; CYANTEK CORPORATION, A DELAWARE CORPORATION; OMG AMERICAS, INC., A OHIO CORPORATION; OMG ELECTRONIC CHEMICALS, LLC, A DELAWARE LIMITED LIABILITY COMPANY; OMG ENERGY HOLDINGS, INC., A DELAWARE CORPORATION; OMG HARKO HOLDINGS, LLC, A DELAWARE LIMITED LIABILITY COMPANY; EAGLEPICHER MEDICAL POWER, LLC, A DELAWARE LIMITED LIABILITY COMPANY; EAGLEPICHER TECHNOLOGIES, LLC, A DELAWARE LIMITED LIABILITY COMPANY; EPEP HOLDING COMPANY, LLC, A DELAWARE LIMITED LIABILITY COMPANY
To: BANK OF AMERICA, N.A., AS COLLATERAL AGENT
Reel/Frame 026740/0353 →
PATENT RELEASE AGREEMENT Recorded Aug 10, 2011
From: PNC BANK, NATIONAL ASSOCIATION, AS ADMINISTRATIVE AGENT
To: OM GROUP, INC., A DELAWARE CORPORATION; OMG AMERICAS, INC., A OHIO CORPORATION; OMG ELECTRONIC CHEMICALS, INC., A DELAWARE LIMITED LIABILITY COMPANY; COMPUGRAPHICS U.S.A. INC., A DELAWARE CORPORATION; OMG ENERGY HOLDINGS, INC., A DELAWARE CORPORATION; EAGLEPICHER TECHNOLOGIES, LLC, A DELAWARE LIMITED LIABILITY COMPANY; EPEP HOLDING COMPANY, LLC, A DELAWARE LIMITED LIABILITY COMPANY; EAGLEPICHER MEDICAL POWER, LLC, A DELAWARE LIMITED LIABILITY COMPANY
Reel/Frame 026727/0485 →
CHANGE OF NAME Recorded Aug 11, 2010
From: OMG ELECTRONIC CHEMICALS, INC.
To: OMG ELECTRONIC CHEMICALS, LLC
Reel/Frame 024812/0920 →
SECURITY AGREEMENT Recorded Mar 11, 2010
From: OM GROUP, INC.; OMG AMERICAS, INC.; OMG ELECTRONIC CHEMICALS, INC.; COMPUGRAPHICS U.S.A. INC.; OM HOLDINGS, INC.; OMG ENERGY HOLDINGS, INC.; EAGLEPICHER TECHNOLOGIES, LLC; EPEP HOLDING COMPANY, LLC; EAGLEPICHER MEDICAL POWER, LLC
To: PNC BANK, NATIONAL ASSOCIATION
Reel/Frame 024066/0130 →
MERGER Recorded Jan 14, 2009
From: ELECTROCHEMICALS INC.; OMG FIDELITY, INC.
To: OMG ELECTRONIC CHEMICALS, INC.
Reel/Frame 022102/0711 →