Electrodeposited copper foil with low repulsive force

Patent metadata

Field	Value
Publication number	US-10190225-B2
Application number	US-201715490608-A
Country	US
Kind code	B2
Filing date	Apr 18, 2017
Priority date	Apr 18, 2017
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

The present disclosure relates to a copper foil that exhibits surprising low repulsive force characteristics; and to methods for manufacturing such copper foils. Typically, the copper foil has (a) a lightness L* value of the nodule untreated side, based on the L*a*b color system, in the range of 75 to 90 and (b) a normal tensile strength in the range of 40 kgf/mm2 to 55 kgf/mm2. The disclosure further relates to flexible printed circuit boards and electronic devices using the above-mentioned copper foils for forming conductive lines therein.

First claim

What is claimed is:

1. A method for manufacturing electrodeposited copper foil comprising:
(a) preparing a copper sulfate electrolyte solution with a chlorine ion concentration of 20 ppm or less;
(b) performing an electrochemical reaction on the copper sulfate electrolyte solution using a current density of about 80 A/dm 2 or less to yield a bare copper foil; and
(c) processing the bare copper foil to yield the electrodeposited copper foil, so that the electrodeposited copper foil has:
(i) a lightness L* value of a nodule untreated side, based on the L*a*b color system, in the range of 75 to 90;
(j) a normal tensile strength in the range of 40 kgf/mm 2 to 55 kgf/mm 2 ; and
(k) a degree of curl, as measured by the lamination curl test, is in the range of 0.45 mm to 3.0 mm;

wherein the processing comprises a surface treatment process.

2. The process of claim 1 , wherein the chlorine ion concentration is about 20 ppm, and wherein the normal tensile strength is in the range of 40 kgf/mm 2 to 45 kgf/mm 2 and the degree of curl, as measured by the lamination curl test, is in the range of 0.45 mm to 1.5 mm.

3. The process of claim 1 , wherein the chlorine ion concentration is about 15 ppm, and wherein the normal tensile strength is in the range of 45 kgf/mm 2 to 50 kgf/mm 2 and the degree of curl, as measured by the lamination curl test, is in the range of 1.5 mm to 2.5 mm.

4. The process of claim 1 , wherein the chlorine ion concentration is about 10 ppm, and wherein the normal tensile strength is in the range of 50 kgf/mm 2 to 55 kgf/mm 2 and the degree of curl, as measured by the lamination curl test, is in the range of 2.5 mm to 3.0 mm.

5. The process of claim 1 , wherein the surface treatment process comprises subjecting the copper foil to an acid washing.

6. The process of claim 5 , further comprising the step of washing the copper foil with water after the acid washing.

7. The process of claim 1 , wherein the surface treatment step comprises a surface roughening of the copper foil.

8. The process of claim 7 , wherein the surface roughening comprises the step of forming nodules on one of a deposit side or a drum side of the electrodeposited copper foil.

9. The process of claim 8 , further comprising the step of cover plating the nodules.

10. The process of claim 9 , further comprising the step of alloying a metal layer onto the cover plating.

11. The process of claim 8 , further comprising the step of passivating each of the deposit side and drum side of the copper foil.

12. The process of claim 11 , wherein the step of passivating comprises applying a passivating agent comprising zinc.

13. The process of claim 12 , further comprising the step of forming an anti-tarnish layer by applying a chromic acid solution to the zinc passivated copper foil.

14. The process of claim 13 , further comprising applying an organic anti-tarnish solution over the chromic treated zinc passivated copper foil.

15. The process of claim 14 , wherein the organic anti-tarnish solution comprises at least one member selected from the group consisting of triazoles, thiazoles, imidazoles and their derivatives.

16. The process of claim 14 , further comprising treating only the Zn/Cr passivated nodule layer with a silane coupling agent.

17. The process of claim 16 , wherein the Zn/Cr passivated nodule layer is washed with water upon completion of the anti-tarnish layer and the silane coupling agent is applied without drying the water washed Zn/Cr passivated nodule layer.

18. A method for manufacturing electrodeposited copper foil comprising:
(a) preparing a copper sulfate electrolyte solution with a chlorine ion concentration of 20 ppm or less;
(b) performing an electrochemical reaction on the copper sulfate electrolyte solution using a current density of about 80 A/dm 2 or less to yield a bare copper foil; and
(c) processing the bare copper foil to yield the electrodeposited copper foil, so that the electrodeposited copper foil has:
(i) a lightness L* value of a nodule untreated side, based on the L*a*b color system, in the range of 75 to 90;
(j) a normal tensile strength in the range of 40 kgf/mm 2 to 55 kgf/mm 2 ; and
(I) a low angle grain boundary (LAGB) value measured after an annealing step to the electrodeposited copper foil is in the range of 3.5% to 7.0%;

wherein the processing comprises a surface treatment process.

19. The process of claim 18 , wherein the surface treatment step comprises a surface roughening step wherein the surface roughening comprises the step of forming nodules on one of a deposit side or a drum side of the electrodeposited copper foil.

20. The process of claim 19 , further comprising the step of cover plating the nodules.

21. The process of claim 18 , wherein the current density is about 60 A/dm 2 , and the electrodeposited copper foil further comprising a low angle grain boundary (LAGB) value measured after annealing is in the range of 3.5% to 3.8% and the lightness L* value of the nodule untreated side is in the range of 75 to 80.

22. The process of claim 18 , wherein the current density is about 70 A/dm 2 , and the electrodeposited copper foil further comprising the LAGB value measured after annealing is in the range of 5.8% to 6.0% and the lightness L* value of the nodule untreated side is in the range of 83 to 87.

23. The process of claim 18 , wherein the current density is about 80 A/dm 2 , and the electrodeposited copper foil further comprising the LAGB value measured after annealing is in the range of 6.4% to 7.0% and the lightness L* value of the nodule untreated side is in the range of 87 to 90.

Assignees

• Chang Chun Petrochemical Co Ltd

Inventors

• Lai Yao-Sheng
• Cheng Kuei-Seng
• Huang Jian-Ming

Classifications

• H01M4/045

  Electrochemical coating; Electrochemical impregnation · CPC title

• C25D1/04 Primary

  Wires; Strips; Foils · CPC title

• C25D5/38

  of refractory metals or nickel · CPC title

• C25D7/0614

  Strips or foils · CPC title

• H01M4/0438

  by electrochemical processing (electroless electrochemical plating C23C18/54) · CPC title