Circuit materials, circuits laminates, and method of manufacture thereof

Patent metadata

Field	Value
Publication number	US-9258892-B2
Application number	US-201414334876-A
Country	US
Kind code	B2
Filing date	Jul 18, 2014
Priority date	Jul 23, 2013
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

A circuit subassembly is disclosed comprising a conductive metal layer and a dielectric substrate layer having a dielectric constant of less than about 3.5 and a dissipation factor of less than about 0.006 at 10 GHz, wherein the composition of the dielectric substrate layer comprises about 5 to about 70 volume percent of borosilicate microspheres that have been treated with an alkaline solution.

First claim

What is claimed is:

1. A circuit subassembly, comprising
a conductive layer disposed on a dielectric substrate layer, wherein the composition of the dielectric substrate layer comprises, based on the volume of the dielectric substrate layer:
about 30 to about 90 volume percent of a polymer matrix material; and
about 5 to about 70 volume percent of hollow borosilicate microspheres
wherein the borosilicate microspheres are a product of a process of subjecting the borosilicate microspheres to an alkaline solution; and wherein the dielectric substrate layer has a dielectric constant of less than about 3.5 and a dissipation factor of less than about 0.006 at 10 GHz.

2. The circuit subassembly of claim 1 , wherein the circuit subassembly has a dissipation factor of less than about 0.0035 at 10 GHz.

3. The circuit subassembly of claim 1 , wherein the circuit subassembly has a passive intermodulation (PIM) that is less than −154 dBc.

4. The circuit subassembly of claim 1 , wherein the mean particle size of the microspheres is less than 70 micrometers.

5. The circuit subassembly of claim 1 , wherein the microspheres further comprise an inert gas within the hollow microspheres.

6. The circuit subassembly of claim 1 , wherein the microspheres have a ferric oxide content of about 0.5 weight percent, as measured by XPS surface analysis, based on the total weight of the composition.

7. The circuit subassembly of claim 1 , wherein the microspheres have a density of 0.20 to 0.60 g/cc.

8. The circuit subassembly of claim 1 , wherein the microspheres have a sodium oxide content of not more than about 5 weight percent, as measured by XPS surface analysis.

9. The circuit subassembly of claim 1 , wherein the microspheres have a sodium oxide content of 2.5 to 4.5 weight percent, as measured by XPS surface analysis.

10. The circuit assembly of claim 1 , wherein the borosilicate microspheres are a product made by a process in which treatment with the alkaline solution reduced the sodium oxide content below a preselected amount.

11. The circuit assembly of claim 10 , wherein the borosilicate microspheres are a product of a process comprising washing the microspheres in a strong aqueous alkaline solution until the measured sodium oxide content is reduced by at least 25 wt. % of the original amount.

12. The circuit assembly of claim 8 , wherein the borosilicate microspheres are a product of a process in which the content of sodium oxide is reduced by at least 2 wt. % as measured by XPS surface analysis.

13. The circuit assembly of claim 1 , wherein the borosilicate microspheres are a product of a process that does not comprise washing or leaching the microspheres with an acidic solution to obtain the final sodium oxide content of the microspheres.

14. The circuit subassembly of claim 1 , wherein the borosilicate microspheres have a median particle diameter of 20 to 100 micrometers.

15. The circuit subassembly of claim 1 , wherein the dielectric substrate layer comprises one or more additional fillers, in an amount from 20 to 80 vol. %, based on the total volume of the filler component.

16. The circuit subassembly of claim 15 , wherein additional filler is silica, fused amorphous silica, or a combination thereof.

17. The circuit subassembly of claim 1 , wherein the polymer matrix material comprises 1,2-polybutadiene, polyisoprene, polyetherimide, a fluoropolymer, polytetrafluoroethylene, polyphenylene ether, polyimide, polyetheretherketone, polyamidimide, polyethylene terephthalate, polyethylene naphthalate, polycyclohexylene terephthalate, or a combination comprising at least one of the foregoing.

18. The circuit subassembly of claim 1 , wherein the polymer matrix material is polytetrafluoroethylene.

19. The circuit subassembly of claim 1 , wherein the polymer matrix material comprises 1,2-polybutadiene, polyisoprene, or a combination of 1,2-polybutadiene and polyisoprene.

20. The circuit subassembly of claim 1 , wherein the polymer matrix material comprises poly(arylene ether).

21. The circuit subassembly of claim 19 , wherein the polybutadiene or polyisoprene polymer is carboxy-functionalized, and comprises butadiene, isoprene, or butadiene and isoprene, and less than 50 weight percent of a co-curable monomer.

22. The circuit subassembly of claim 1 , further comprising a second conductive layer disposed on a side of the dielectric substrate layer opposite a first said conductive layer.

23. The circuit subassembly of claim 1 , wherein the conductive layer is a copper foil.

24. The circuit subassembly of claim 1 , wherein the conductive layer is etched to provide a circuit.

25. The circuit subassembly of claim 1 , wherein the conductive layer is in direct contact with the dielectric substrate layer or optional adhesive layer, without an intervening layer, wherein an optional adhesive layer is less than 10 percent of the thickness of the dielectric substrate layer.

26. The circuit subassembly of claim 1 , wherein a bond ply is disposed between and in adjacent contact with two patterned conductive layers, wherein each conductive layer is attached to a dielectric layer.

27. A circuit comprising the circuit subassembly of claim 1 .

28. A multilayer circuit comprising the circuit subassembly of claim 1 .

29. The multilayer circuit of claim 28 , wherein the circuit subassembly is used in an antenna.

30. A method of making a circuit subassembly, the method comprising:
treating hollow borosilicate microspheres with an alkaline solution;
combining the hollow borosilicate microspheres with a polymer matrix material to form a dielectric composite material;
forming a layer of the dielectric composite material, thereby obtaining a dielectric substrate layer;
disposing a conductive layer on the dielectric substrate layer; and
laminating the dielectric substrate layer and the conductive layer, wherein the dielectric substrate layer exhibits a dielectric constant of less than about 3.5 and a dissipation factor of less than about 0.006 at 10 GHz.

31. The method of claim 30 , wherein treating the hollow borosilicate microsphere with an alkaline solution comprises washing the borosilicate microspheres with an aqueous alkaline solution to effectively reduce the sodium oxide content of the borosilicate microspheres to a preselected amount, as determined by XPS surface analysis.

32. The method of claim 31 , wherein treating the borosilicate microspheres with an alkaline solution comprises reducing the sodium oxide content by at least 25 wt. % of the original amount, as determined by XPS surface analysis.

33. The method of claim 31 , wherein treating the borosilicate microspheres with an alkaline solution comprises reducing the sodium content by at least 1 wt. %, as determined by XPS surface analysis.

34. The method of claim 31 , wherein the borosilicate microspheres are not washed with a strong acidic solution to effectively lower and obtain a final sodium oxide content in the borosilicate microspheres, as determined by XPS surface analysis.

Assignees

• Rogers Corp

Inventors

• Crosley Jessica

Classifications

• C03C11/00

  Multi-cellular glass {; Porous or hollow glass or glass particles} · CPC title

• H05K1/0373 Primary

  containing additives, e.g. fillers (H05K1/036 takes precedence) · CPC title

• H05K1/024

  Dielectric details, e.g. changing the dielectric material around a transmission line · CPC title

• H05K1/0243

  Printed circuits associated with mounted high frequency components · CPC title

• C03C23/008

  comprising a lixiviation step · CPC title