Apparatus with a Wire Bond and Method of Forming the Same

• US 20110186334A1
• Filed: 02/18/2011
• Published: 08/04/2011
• Est. Priority Date: 08/18/2008
• Status: Active Grant

• Current Assignee: HzO, Inc.
• Original Assignee: Semblant Global Limited
• Inventors: Humphries, Mark Robson, Smith, Rodney Edward, Ferdinandi, Frank
• Granted Patent: US 8,618,420 B2
• Time in Patent Office: Days
• US Class Current: 174/251
• CPC Class Codes: B23K 1/20 Preliminary treatment of work or areas to be soldered, e.g. in respect of a galvanic coating preparation of surfaces in particular ways, see the relevant classes for the treatments or the materials treated, e.g. C04B, C23C
• CPC Class Codes: B23K 20/24 Preliminary treatment
• CPC Class Codes: B23K 31/02 relating to soldering or welding dip or wave soldering in the manufacture of printed circuits H05K3/34
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• 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 24/85 using a wire connector wire bonding in general B23K20/004
• 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 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01018 Argon [Ar]
• CPC Class Codes: H01L 2924/01028 Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01047 Silver [Ag]
• CPC Class Codes: H01L 2924/0105 Tin [Sn]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H05K 1/00 : Printed circuits
• CPC Class Codes: H05K 1/09 : Use of materials for the conductive, e.g. metallic pattern
• CPC Class Codes: H05K 2203/049 : Wire bonding

Abstract

In some embodiments, a printed circuit board (PCB) comprises a substrate comprising an insulating material. The PCB further comprises a plurality of conductive tracks attached to at least one surface of the substrate. The PCB further comprises a multi-layer coating deposited on the at least one surface of the substrate. The multi-layer coating (i) covers at least a portion of the plurality of conductive tracks and (ii) comprises at least one layer formed of a halo-hydrocarbon polymer. The PCB further comprises at least one electrical component connected by a solder joint to at least one conductive track, wherein the solder joint is soldered through the multi-layer coating such that the solder joint abuts the multi-layer coating.

Claims

1. A printed circuit board, comprising:

a substrate comprising an insulating material;

a plurality of conductive tracks attached to at least one surface of the substrate;

a coating deposited on the at least one surface of the substrate, wherein;

the coating covers at least a portion of the plurality of conductive tracks; and

comprises at least one halo-hydrocarbon polymer; and

at least one conductive wire that is connected by a wire bond to at least one conductive track, the wire bond formed through the coating without prior removal of the coating such that the wire bond abuts the coating.

2. The printed circuit board of claim 1, wherein the wire bond abuts the coating along a plane parallel to the at least one surface of the substrate.

3. The printed circuit board of claim 1, wherein the wire bond is at least one of:

a ball bond; and

a wedge bond.

4. The printed circuit board of claim 1, wherein the wire comprises at least one of:

gold;

aluminum;

silver;

copper;

nickel; and

iron.

5. The printed circuit board of claim 1, wherein at least a portion of the wire is covered with the coating.

6. The printed circuit board of claim 1, wherein the coating has a thickness of from 1 nanometers to 2 micrometers.

7. The printed circuit board of claim 1, wherein the coating has a thickness of from 10 nanometers to 100 nanometers.

8. The printed circuit board of claim 1, wherein the at least one halo-hydrocarbon polymer is a fluoro-hydrocarbon polymer.

9. The printed circuit board of claim 1, wherein the wire bond is formed at a particular region of the substrate, the formation of the wire bond altering the coating at the particular region without altering the coating at other regions of the substrate.

10. The printed circuit board of claim 9, wherein:

the coating is not removed from the particular region of the substrate prior to the formation of the wire bond; and

the formation of the wire bond alters the coating at the particular region of the substrate by selectively removing the coating from the particular region of the substrate.

11. The printed circuit board of claim 1, further comprising at least one electrical component connected by a solder joint to at least one conductive track, wherein the solder joint is soldered through the coating such that the solder joint abuts the coating.

12. The printed circuit board of claim 1, wherein the wire bond is formed at a first region of the substrate, the first region coated with the coating, and further comprising:

at least one electrical component connected by a solder joint to at least one conductive track at a second region of the substrate, the second region coated with another coating.

13. The printed circuit board of claim 1, further comprising a contact attached to at least one surface of the substrate, the contact coated with the coating, the contact operable to conduct an electrical signal through the coating to another contact.

14. The printed circuit board of claim 1, wherein the coating is deposited such that a metal halide layer covers at least a portion of the plurality of conductive tracks.

15. The printed circuit board of claim 1, wherein the coating is deposited such that there is essentially no metal halide layer between the plurality of conductive tracks and the coating.

16. A method, comprising:

attaching a plurality of conductive tracks to at least one surface of a substrate comprising an insulating material;

depositing a coating on the at least one surface of the substrate, the coating covering at least a portion of the plurality of conductive tracks, the coating comprising at least one halo-hydrocarbon polymer; and

forming a wire bond between at least one conductive wire and at least one conductive track, the wire bond formed through the coating without prior removal of the coating such that the wire bond abuts the coating.

17. The method of claim 16, wherein the wire bond abuts the coating along a plane parallel to the at least one surface of the substrate.

18. The method of claim 16, wherein the wire bond is at least one of:

a ball bond; and

a wedge bond.

19. The method of claim 16, wherein the wire comprises at least one of:

gold;

aluminum;

silver;

copper;

nickel; and

iron.

20. The method of claim 16, wherein at least a portion of the wire is covered with the coating prior to formation of the wire bond.

21. The method of claim 16, wherein the coating has a thickness of from 1 nanometers to 2 micrometers.

22. The method of claim 16, wherein the coating has a thickness of from 10 nanometers to 100 nanometers.

23. The method of claim 16, wherein the at least one halo-hydrocarbon polymer is a fluoro-hydrocarbon polymer.

24. The method of claim 16, wherein the wire bond is formed at a particular region of the substrate, the formation of the wire bond altering the coating at the particular region without altering the coating at other regions of the substrate.

25. The method of claim 24, wherein:

the coating is not removed from the particular region of the substrate prior to the formation of the wire bond; and

the formation of the wire bond alters the coating at the particular region of the substrate by selectively removing the coating from the particular region of the substrate.

26. The method of claim 16, further comprising:

after depositing the coating, soldering through the coating to form a solder joint between an electrical component and at least one conductive track attached to the substrate, the solder joint abutting the coating.

27. The method of claim 16, wherein the wire bond is formed at a first region of the substrate, the first region coated with the coating, and further comprising:

depositing another coating on a second region of the substrate; and

soldering through the other coating on the second region of the substrate to form a solder joint between an electrical component and at least one conductive track attached to the substrate.

28. The method of claim 16, further comprising:

affixing a contact to at least one surface of the substrate, the contact coated with the coating, the contact operable to conduct an electrical signal through the coating to another contact.

29. The method of claim 16, wherein depositing the coating comprises depositing a first layer of the coating, and further comprising, after formation of the wire bond, depositing a second layer of the coating on the at least one surface of the substrate, the second layer of the coating covering at least a portion of the wire bond.

30. The method of claim 16, wherein the wire bond is a bare die wire bond.

31. The method of claim 16, wherein the substrate is comprised in a printed circuit board, and further comprising:

after formation of the wire bond, depositing a conformal coating on the printed circuit board, the conformal coating comprising at least one halo-hydrocarbon polymer, the conformal coating having at least one of the following properties;

solder-through capability;

capability to permit wire bonding through the conformal coating; and

conductivity along an axis perpendicular to a surface coated with the conformal coating.