Apparatus with a multi-layer coating and method of forming the same

• US 9,055,700 B2
• Filed: 08/11/2009
• Issued: 06/09/2015
• Est. Priority Date: 08/18/2008
• Status: Active Grant

• Current Assignee: HzO, Inc.
• Original Assignee: Semblant Limited (HzO, Inc.)
• Inventors: Humphries, Mark Robson, Ferdinandi, Frank, Smith, Rodney Edward
• Primary Examiner(s): Aychillhum, Andargie M
• Application Number:
  US13/059,602
• Publication Number:
  US 20110253429A1
• Time in Patent Office: 2,128 Days
• Field of Search: 174/251, 174/250, 174/258
• US Class Current: 1/1
• CPC Class Codes: H01H 13/78 characterised by the contacts or the contact sites
• CPC Class Codes: H01H 2215/004 Collapsible dome or bubble
• CPC Class Codes: H01H 2229/012 Vacuum deposition
• CPC Class Codes: H01L 2224/06 of a plurality of bonding areas
• CPC Class Codes: H01L 2224/43848 Thermal treatments, e.g. annealing, controlled cooling
• CPC Class Codes: H01L 2224/45014 Ribbon connectors, e.g. rectangular cross-section
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45105 Gallium (Ga) as principal constituent
• CPC Class Codes: H01L 2224/45109 Indium (In) as principal constituent
• CPC Class Codes: H01L 2224/45111 Tin (Sn) as principal constituent
• CPC Class Codes: H01L 2224/45113 Bismuth (Bi) as principal constituent
• CPC Class Codes: H01L 2224/45116 Lead (Pb) as principal constituent
• CPC Class Codes: H01L 2224/4512 Antimony (Sb) as principal constituent
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45138 the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
• CPC Class Codes: H01L 2224/45139 Silver (Ag) 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 2224/45149 Manganese (Mn) as principal constituent
• CPC Class Codes: H01L 2224/45155 Nickel (Ni) as principal constituent
• CPC Class Codes: H01L 2224/45157 : Cobalt (Co) as principal constituent
• CPC Class Codes: H01L 2224/4516 : Iron (Fe) as principal constituent
• CPC Class Codes: H01L 2224/45164 : Palladium (Pd) as principal constituent
• CPC Class Codes: H01L 2224/45166 : Titanium (Ti) as principal constituent
• CPC Class Codes: H01L 2224/45169 : Platinum (Pt) as principal constituent
• CPC Class Codes: H01L 2224/4517 : Zirconium (Zr) as principal constituent
• CPC Class Codes: H01L 2224/45171 : Chromium (Cr) as principal constituent
• CPC Class Codes: H01L 2224/45173 : Rhodium (Rh) as principal constituent
• CPC Class Codes: H01L 2224/45178 : Iridium (Ir) as principal constituent
• CPC Class Codes: H01L 2224/4518 : Molybdenum (Mo) as principal constituent
• CPC Class Codes: H01L 2224/45184 : Tungsten (W) as principal constituent
• CPC Class Codes: H01L 2224/45565 : Single coating layer
• CPC Class Codes: H01L 2224/45599 : Material
• CPC Class Codes: H01L 2224/45644 : Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/4569 : with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/48091 : Arched
• CPC Class Codes: H01L 2224/48455 : Details of wedge bonds
• CPC Class Codes: H01L 2224/48463 : the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/48464 : the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 2224/48599 : Principal constituent of the connecting portion of the wire connector being Gold (Au)
• CPC Class Codes: H01L 2224/48699 : Principal constituent of the connecting portion of the wire connector being Aluminium (Al)
• CPC Class Codes: H01L 2224/8502 : Applying permanent coating, e.g. in-situ coating
• CPC Class Codes: H01L 2224/85201 : Compression bonding
• CPC Class Codes: H01L 2224/85205 : Ultrasonic bonding
• CPC Class Codes: H01L 2224/85439 : Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/85444 : Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/85447 : Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/85484 : Tungsten (W) as principal constituent
• CPC Class Codes: H01L 2224/85611 : Tin (Sn) as principal constituent
• 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01007 : Nitrogen [N]
• CPC Class Codes: H01L 2924/01011 : Sodium [Na]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01016 : Sulfur [S]
• CPC Class Codes: H01L 2924/01018 : Argon [Ar]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01021 : Scandium [Sc]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01024 : Chromium [Cr]
• CPC Class Codes: H01L 2924/01025 : Manganese [Mn]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/0103 : Zinc [Zn]
• CPC Class Codes: H01L 2924/01031 : Gallium [Ga]
• CPC Class Codes: H01L 2924/01032 : Germanium [Ge]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/0104 : Zirconium [Zr]
• CPC Class Codes: H01L 2924/01042 : Molybdenum [Mo]
• 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 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01051 : Antimony [Sb]
• CPC Class Codes: H01L 2924/01072 : Hafnium [Hf]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• 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 2924/01083 : Bismuth [Bi]
• CPC Class Codes: H01L 2924/01087 : Francium [Fr]
• CPC Class Codes: H01L 2924/01327 : Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/19042 : being an inductor
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/206 : Length ranges
• CPC Class Codes: H01L 2924/2075 : larger or equal to 1 micron less than 10 microns
• CPC Class Codes: H01L 2924/20751 : larger or equal to 10 microns less than 20 microns
• CPC Class Codes: H01L 2924/20752 : larger or equal to 20 microns less than 30 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 2924/20758 : larger or equal to 80 microns less than 90 microns
• CPC Class Codes: H01L 2924/20759 : larger or equal to 90 microns less than 100 microns
• CPC Class Codes: H01L 2924/2076 : equal to or larger than 100 microns
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H05K 2201/015 : Fluoropolymer, e.g. polytetrafluoroethylene [PTFE]
• CPC Class Codes: H05K 2201/0179 : Thin film deposited insulating layer, e.g. inorganic layer for printed capacitor
• CPC Class Codes: H05K 2201/0195 : Dielectric or adhesive layers comprising a plurality of layers, e.g. in a multilayer structure
• CPC Class Codes: H05K 2203/049 : Wire bonding
• CPC Class Codes: H05K 3/222 : Completing of printed circuits by adding non-printed jumper connections printed jumper connections H05K3/4685
• CPC Class Codes: H05K 3/282 : for inhibiting the corrosion of the circuit, e.g. for preserving the solderability
• CPC Class Codes: H05K 3/284 : for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: H05K 3/328 : by welding
• CPC Class Codes: Y10T 29/49155 : Manufacturing circuit on or in base

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

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;

the solder joint is formed on a particular region of the substrate after a substantially continuous layer of the multi-layer coating is deposited on the substrate; and

the soldering alters the multi-layer coating at the particular region of the substrate without altering the multi-layer coating at other regions of the substrate.

2. The printed circuit board of claim 1, wherein the multi-layer coating has a thickness of from 1 nanometer to 10 micrometers.

3. The printed circuit board of claim 1, wherein the multi-layer coating comprises a first layer and a second layer that are distinct from each other, the first layer and the second layer comprising different polymers.

4. The printed circuit board of claim 1, wherein:

the multi-layer coating comprises a first layer comprising a particular type of polymer;

the multi-layer coating comprises a second layer comprising the particular type of polymer;

the polymer in the first layer differs from the polymer in the second layer with respect to at least one of the following properties;

molecular weight;

chemical composition;

structure;

geometry; and

porosity.

5. The printed circuit board of claim 1, wherein:

the multi-layer coating comprises a particular layer of a first polymer and another layer of a second polymer, the layers abutting each other; and

the layers are graded such that the multi-layer coating transitions from the first polymer to the second polymer.

6. The printed circuit board of claim 1, wherein the multi-layer coating comprises a particular layer formed of a halo-hydrocarbon polymer and another layer formed of a polymer free of halogen atoms.

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

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

9. The printed circuit board of claim 1, wherein the halo-hydrocarbon polymer comprises one or more fluoro-hydrocarbons.

10. The printed circuit board of claim 1, wherein the multi-layer coating comprises:

a first layer comprising a fluoro-hydrocarbon material; and

a second layer comprising a chlorofluoro-hydrocarbon material.

11. The printed circuit board of claim 10, wherein the second layer is formed between the first layer and the plurality of conductive tracks.

12. The printed circuit board of claim 10, wherein the first layer is formed between the second layer and the plurality of conductive tracks.

13. The printed circuit board of claim 1, wherein the soldering alters the multi-layer coating at the particular region of the substrate by removing the multilayer coating from the particular region of the substrate without removing the multilayer coating from other regions of the substrate.

14. The printed circuit board of claim 1, wherein:

a first region of the substrate is coated with the multi-layer coating; and

a second region of the substrate is coated with another coating.

15. The printed circuit board of claim 14, further comprising a contact attached to at least one surface of the substrate, the contact coated with the single-layer coating, the contact operable to conduct an electrical signal through the single-layer coating to another contact.

16. 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 multi-layer coating, the contact operable to conduct an electrical signal through the multi-layer coating to another contact.

17. The printed circuit board of claim 1, further comprising at least one wire that is connected by a wire bond to at least one conductive track, the wire bond formed through the multi-layer coating such that the wire bond abuts the multi-layer coating.

18. The printed circuit board of claim 1, wherein heating a flux at a particular region of the substrate alters the multi-layer coating at the particular region of the substrate without altering the multi-layer coating at other regions of the substrate.

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

an epoxy resin bonded glass fabric;

a synthetic resin bonded paper;

an epoxy;

a cotton paper;

a cardboard;

a natural wood based material; and

a synthetic wood based material.

20. The printed circuit board of claim 1, wherein at least one layer of the multi-layer coating comprises a metal material.

21. A method, comprising:

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

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

after depositing the multi-layer coating, soldering through the multi-layer 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 multi-layer coating;

the solder joint is formed on a particular region of the substrate after a substantially continuous layer of the multi-layer coating is deposited on the substrate; and

the soldering alters the multi-layer coating at the particular region of the substrate without altering the multi-layer coating at other regions of the substrate.

22. The method of claim 21, wherein the multi-layer coating has a thickness of from 1 nanometer to 10 micrometers.

23. The method of claim 21, wherein the multi-layer coating comprises a first layer and a second layer that are distinct from each other, the first layer and the second layer comprising different polymers.

24. The method of claim 21, wherein:

the multi-layer coating comprises a first layer comprising a particular type of polymer;

the multi-layer coating comprises a second layer comprising the particular type of polymer;

the polymer in the first layer differs from the polymer in the second layer with respect to at least one of the following properties;

molecular weight;

chemical composition;

structure;

geometry; and

porosity.

25. The method of claim 21, wherein:

the multi-layer coating comprises a particular layer of a first polymer and another layer of a second polymer, the layers abutting each other; and

the layers are graded such that the multi-layer coating transitions from the first polymer to the second polymer.

26. The method of claim 21, wherein the multi-layer coating comprises a particular layer formed of a halo-hydrocarbon polymer and another layer formed of a polymer free of halogen atoms.

27. The method of claim 21, wherein the multi-layer coating is deposited such that a metal halide layer covers at least a portion of the plurality of conductive tracks.

28. The method of claim 21, wherein the multi-layer coating is deposited such that there is essentially no metal halide layer between the plurality of conductive tracks and the multi-layer coating.

29. The method of claim 21, wherein the halo-hydrocarbon polymer comprises one or more fluoro-hydrocarbons.

30. The method of claim 21, wherein the multi-layer coating comprises:

a first layer comprising a fluoro-hydrocarbon material; and

a second layer comprising a chlorofluoro-hydrocarbon material.

31. The method of claim 30, wherein the second layer is formed between the first layer and the plurality of conductive tracks.

32. The method of claim 30, wherein the first layer is formed between the second layer and the plurality of conductive tracks.

33. The method of claim 21, wherein the soldering alters the multi-layer coating at the particular region of the substrate by removing the multi-layer coating from the particular region of the substrate without removing the multi-layer coating from other regions of the substrate.

34. The method of claim 21, wherein:

a first region of the substrate is coated with the multi-layer coating; and

a second region of the substrate is coated with another coating.

35. The method of claim 34, further comprising:

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

36. The method of claim 21, further comprising:

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

37. The method of claim 21, further comprising:

forming a wire bond through the multi-layer coating, the wire bond connecting at least one wire to at least one conductive track, the wire bond abutting the multilayer coating.

38. The method of claim 21, further comprising:

modifying a wetting characteristic of the multi-layer coating by at least one of the following;

plasma cleaning;

plasma etching;

plasma activation;

plasma polymerization and coating; and

liquid based chemical etching.

39. The method of claim 21, wherein the multi-layer coating is deposited by at least one of the following:

plasma deposition;

chemical vapor deposition;

metallo-organic-chemical vapor deposition;

molecular beam epitaxy;

spray coating;

sputtering; and

spin coating.

40. The method of claim 21, wherein:

the substrate is comprised in a printed circuit board; and

the coating causes the printed circuit board to be flame retardant.

41. The method of claim 21, further comprising, during the soldering, controlling wetting of the multi-layer coating.

42. The method of claim 21, further comprising balancing solderability and protectability of coating, the balancing achieved at least in part by controlling porosity and wetting of the multi-layer coating.

43. The method of claim 21, further comprising:

after formation of the solder joint, 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.

44. The method of claim 21, further comprising:

after formation of the solder joint, depositing a conformal coating on the printed circuit board, the conformal coating comprising at least one halo-hydrocarbon polymer, wherein;

the conformal coating is insulative along an axis perpendicular to a surface coated with the conformal coating; and

the conformal coating has at least one of the following properties;

solder-through capability; and

capability to permit wire bonding through the conformal coating.