Copper foil, copper-clad laminate board, method for producing printed wiring board, method for producing electronic apparatus, method for producing transmission channel, and method for producing antenna

Patent metadata

Field	Value
Publication number	US-10448507-B2
Application number	US-201715405517-A
Country	US
Kind code	B2
Filing date	Jan 13, 2017
Priority date	Jan 15, 2016
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

To provide a copper foil and a copper-clad laminate board that have a favorably suppressed transmission loss even in the use thereof in a high frequency circuit board that is folded in use or bent in use. A copper foil having a number of times of folding of 1 or more in a folding test under a prescribed condition for a copper-clad laminate board containing the copper foil having adhered thereto an insulating substrate.

First claim

The invention claimed is:

1. A copper foil having a number of times of folding of 1 or more in a folding test under the following condition (G), when the copper foil is adhered in any one of the following conditions (D) to (F) to any one of the following insulating substrates (A) to (C), the insulating substrate having a thickness of 50 μm, to be a copper-clad laminate board,
(A) a fluorine resin,
(B) a polyimide resin having a dielectric dissipation factor of 0.01 or less, and
(C) a liquid crystal polymer resin,
(D) for a case where the insulating substrate is the fluorine resin, a pressure of 5 MPa, a heating temperature and a heating time of 350° C. for 30 minutes,
(E) for a case where the insulating substrate is the polyimide resin having a dielectric dissipation factor of 0.01 or less, a pressure of 4 MPa, a heating temperature and a heating time of any one of the following (E-1) to (E-4):
(E-1) 370° C. for 0.8 second,
(E-2) 370° C. for 2 seconds,
(E-3) 350° C. for 4 seconds, and
(E-4) 300° C. for 10 minutes, and
(F) for a case where the insulating substrate is the liquid crystal polymer resin, a pressure of 3.5 MPa, a heating temperature and a heating time of 300° C. for 10 minutes,
(G) folding test condition:
in a case where a thickness of the copper foil is smaller than 12 μm, the copper foil after adhering on the insulating substrate to form the copper-clad laminate board is subjected to copper plating to make a total thickness of the copper foil and the copper plating of 12 μm, and the condition of the copper plating is as follows,
condition of the copper plating:
composition of plating solution: concentration of copper: 100 g/L, concentration of sulfuric acid: 100 g/L
temperature of plating solution: 50° C.
current density: 0.8 A/dm 2 , and

in a case where a thickness of the copper foil is larger than 12 μm, the copper foil after adhering on the insulating substrate to form the copper-clad laminate board is etched to make the thickness of the copper foil of 12 μm,
in a case where a thickness of the copper foil is 12 μm, the thickness of the copper foil is not adjusted,
the thickness of the copper foil is calculated by the following expression:
thickness of copper foil (μm)=(weight of specimen of copper foil (g))/((area of specimen of copper foil (cm 2 ))×(density of copper, 8.94 (g/cm 3 )))×10 4 (μm/cm),

the thickness of the copper foil after adhering the copper foil and the insulating substrate is calculated by the following expression, and in the case where a total thickness of the copper foil and the copper plating is calculated by the following expression, with replacing “thickness of copper foil (μm)” with “total thickness of the copper foil and the copper plating (μm)”, and “copper foil” with “copper foil and copper plating” in the following expression,
thickness of copper foil (μm)=((weight of specimen of the laminate of the copper foil and the insulating substrate before etching (g))−(weight of the insulating substrate after removing the copper foil entirely from the specimen by etching (g)))/((area of specimen of the laminate of the copper foil and the insulating substrate (cm 2 ))×(density of copper, 8.94 (g/cm 3 )))×10 4 (μm/cm),

a number of test pieces having a width of 12.7 mm and a length of 100 mm are cut out from the copper-clad laminate board in such a manner that a width direction of the test piece is in parallel to a transverse direction, and a length direction of the test piece is in parallel to a machine direction, and then, the test piece is folded (180° contact folding) with the copper foil directed outward by pressing with a load of 1,000 N in the direction of a folding axis in parallel to the width direction of the test piece and perpendicular to the length direction of the test piece, and then the presence of a crack in the copper foil is confirmed,
in a case where a crack is observed, a cross section of the copper foil perpendicular to the folding axis of the test piece and in parallel to the thickness direction of the copper foil is observed to measure the length of the crack,
in a case where the length of the crack is 3 μm or more, it is determined that a crack is observed,
in a case where the length of the crack is less than 3 μm, it is determined that no crack is observed,
the number of times of the observation of a crack in the copper foil is designated as the number of times of folding of the copper foil,
in a case where no crack is observed, the test piece is again flattened by pressing with a load of 1,000 N, and then, the test piece is again folded in the same manner as above,
when the observation of the cross section is performed to determine that no crack is observed because the length of the crack is less than 3 μm, the same evaluation is performed, by using a different test piece, with one more time of folding than the number of times of folding wherein it is determined that no crack is observed, and
the evaluation is performed three times, and the average value of the number of times of folding in the three times evaluations is designated as the number of times of folding.

2. The copper foil according to claim 1 , wherein the copper foil satisfies at least one of the following conditions (2-1) to (2-2):
(2-1) the copper foil has a number of cracks having a depth of 1 μm or more from a surface of the copper foil being 3 or less after a sliding bending test under the following condition (H) for a copper-clad laminate board containing the copper foil having any one of the following insulating substrates (A) to (C), the insulating substrates having a thickness of 50 μm, adhered to the copper foil in any one of the following conditions (D) to (F), in an observation of a region having a size of a thickness of the copper foil×100 μm on a cross section of the copper foil in parallel to a sliding direction in the sliding bending test;
(2-2) the copper foil has a number of cracks having a depth of 2 μm or more from a surface of the copper foil being 2 or less after a sliding bending test under the following condition (H) for a copper-clad laminate board containing the copper foil having any one of the following insulating substrates (A) to (C), the insulating substrates having a thickness of 50 μm, adhered to the copper foil in any one of the following conditions (D) to (F), in an observation of a region having a size of a thickness of the copper foil×100 μm on a cross section of the copper foil in parallel to a sliding direction in the sliding bending test,
(A) a fluorine resin,
(B) a polyimide resin having a dielectric dissipation factor of 0.01 or less, and
(C) a liquid crystal polymer resin,
(D) for a case where the insulating substrate is the fluorine resin, a pressure of 5 MPa, a heating temperature and a heating time of 350° C. for 30 minutes,
(E) for a case where the insulating substrate is the polyimide resin having a dielectric dissipation factor of 0.01 or less, a pressure of 4 MPa, a heating temperature and a heating time of any one of the following (E-1) to (E-4):
(E-1) 370° C. for 0.8 second,
(E-2) 370° C. for 2 seconds,
(E-3) 350° C. for 4 seconds, and
(E-4) 300° C. for 10 minutes, and
(F) for a case where the insulating substrate is the liquid crystal polymer resin, a pressure of 3.5 MPa, a heating temperature and a heating time of 300° C. for 10 minutes,
(H) sliding bending test condition:
in a case where a thickness of the copper foil is smaller than 12 μm, the copper foil after adhering on the insulating substrate to form the copper-clad laminate board is subjected to copper plating to make a total thickness of the copper foil and the copper plating of 12 μm, and the condition of the copper plating is as follows,
condition of the copper plating:
composition of plating solution: concentration of copper: 100 g/L, concentration of sulfuric acid: 100

Assignees

• Jx Nippon Mining & Metals Corp

Inventors

• Fukuchi Ryo

Classifications

• C25D5/48

  After-treatment of electroplated surfaces · CPC title

• C25D3/562

  containing more than 50% by weight of iron or nickel or cobalt · CPC title

• H05K2201/0355

  Metal foils · CPC title

• H05K1/0393

  Flexible materials (H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups) · CPC title

• C25D9/08

  by cathodic processes · CPC title