Surface-treated electrolytic copper foil and method for wireless charging of flexible printed circuit board

Patent metadata

Field	Value
Publication number	US-9673646-B1
Application number	US-201615241264-A
Country	US
Kind code	B1
Filing date	Aug 19, 2016
Priority date	Aug 19, 2016
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

Disclosed are novel copper foils used as components of wireless charging systems. The copper foils can be laminated to produce flexible copper clad laminates, which can then be etched to form printed circuits (coils). The coils can be used as either, or both, of a receiver wireless charging circuit and/or a transmitter wireless charging circuit. Regulation of the chemical and physical properties of the copper foil produces higher efficiencies in the wireless charging system components.

First claim

The invention claimed is:

1. A surface treated copper foil comprising:
(a) a copper content greater than 90%;
(b) (R max −Rz)/Rz of a laminate side of the copper foil is lower than 0.9;
(c) a tensile strength reduction rate is lower than 15% after 200° C.×1 hr annealing;
(d) based on a total sum of texture coefficients of a (111) plane, a (200) plane, a (220) plane and a (311) plane of the surface treated copper foil, a sum of the texture coefficients of the (200) plane and the (220) plane of the surface treated copper foil is greater than 50%, wherein texture coefficients of the surface treated copper foil for each of a (111) plane, a (200) plane, a (220) plane and a (311) plane is obtained by calculation from measurement of X-ray diffraction intensity on a resist side after 200° C.×1 hr. annealing; wherein the tensile strength is in the range of 29 to 39 kg/mm 2 at room temperature.

2. The surface treated copper foil of claim 1 , wherein the surface roughness (Rz) of the laminate side is in the range of 0.7 to 3.0 μm.

3. The surface treated copper foil of claim 1 , wherein a nickel content of the laminate side is lower than 500 μg/dm 2 .

4. The surface treated copper foil of claim 1 , wherein the TC (111) is lower than 1.0 after 200° C.×1 hr. annealing.

5. The surface treated copper foil of claim 1 , wherein the TC (200) is larger than 1.0 after 200° C.×1 hr. annealing.

6. The surface treated copper foil of claim 1 , wherein the surface roughness of resist side is lower than 2.2 μm.

7. The surface treated copper foil of claim 1 , wherein the thickness of the copper foil is in the range of 35 to 210 μm.

8. The surface treated copper foil of claim 7 , wherein the thickness is in the range of 35 to 70 μm.

9. The surface treated copper foil of claim 1 , further comprising a layer of copper nodules.

10. The surface treated copper foil of claim 9 , further comprising a silane coupling agent.

11. The surface treated copper foil of claim 9 , further comprising a Zn treatment.

12. The surface treated copper foil of claim 9 , further comprising a chromate treatment.

13. A flexible copper clad laminate comprising two layers of the surface treated copper foil according to claim 1 laminated to composite film.

14. The flexible copper clad laminate according to claim 13 , wherein the composite film comprises a polyimide sandwiched between two layers of thermoplastic film.

15. A method of making the flexible copper clad laminate of claim 13 comprising;
providing two spaced layers of the surface treated copper foil;
providing the composite film between the spaced layers of copper foil;
feeding the two layers of copper foil and the composite film through a hot press at a temperature in the range of 300°˜400° C. for a time period of about 2 minutes to form a two layer flexible copper clad laminate.

16. The method of claim 15 further comprising etching the copper clad laminate to form a circuit.

17. The method according to claim 16 , wherein the circuit is a coil of a wireless charging flexible printed circuit board.

18. A wireless charging receiver comprising the surface treated copper foil of claim 1 .

19. The wireless charging receiver of claim 18 , wherein the receiver is one selected from the group consisting of smartphones, tablets, wearables, automobiles, industrial machinery and combinations thereof.

20. A wireless charging transmitter comprising the surface treated copper foil of claim 1 .

21. The wireless charging transmitter of claim 20 incorporated into at least one of a desk, a conference table, a coffee table, airport seating, theater seating, airplanes and an automobile.

Assignees

• Chang Chun Petrochemical Co Ltd

Inventors

• Cheng Kuei-Sen
• Lai Yao-Sheng

Classifications

• H02J7/70 Primary

  characterised by the mechanical construction · CPC title

• C22F1/08

  of copper or alloys based thereon · CPC title

• B29L2009/00

  Layered products · CPC title

• B29L2031/3425

  Printed circuits · CPC title

• B29C66/8341

  Roller, cylinder or drum types; Band or belt types; Ball types (B29C66/8351 takes precedence) · CPC title