U.S. patent application number 10/720579 was filed with the patent office on 2004-06-03 for method for manufacturing very low roughness electrodeposited copper foil and electrodeposited copper foil manufactured thereby.
This patent application is currently assigned to LG CABLE LTD.. Invention is credited to Choi, Chang Hee, Jo, Cha Jae, Ki, Joon Seo, Kim, Jeong Ik, Kim, Sangyum, Moon, Hong Gi, Woo, Kyung Nyung.
Application Number | 20040104118 10/720579 |
Document ID | / |
Family ID | 32388281 |
Filed Date | 2004-06-03 |
United States Patent
Application |
20040104118 |
Kind Code |
A1 |
Kim, Sangyum ; et
al. |
June 3, 2004 |
Method for manufacturing very low roughness electrodeposited copper
foil and electrodeposited copper foil manufactured thereby
Abstract
The present invention relates to a method for manufacturing a
low roughness electrodeposited copper foil, and an electrodeposited
copper foil manufactured thereby, and uses an electrolyte which
basically consists of a sulfuric acid, a copper ion and a chloride
ion is adapted with an additive which consists of a HEC
(Hydroxyethyl Cellulose) of 0.05.about.50 ppm, a SPS
(bis(sodiumsulfopropyl)disulfide) of 0.05.about.20 ppm, and a
gelatin of 0.1.about.100 ppm. The present invention is adapted to
manufacture a low roughness electrodeposited copper foil using a
conventional copper foil manufacture facility and the
electrodeposited copper foil according to the present invention is
adapted as a material for a copper clad laminate for a printed
circuit substrate and an electrode material for a lithium ion
battery.
Inventors: |
Kim, Sangyum; (Gyeonggi-do,
KR) ; Choi, Chang Hee; (Gyeonggi-do, KR) ; Jo,
Cha Jae; (Gyeonggi-do, KR) ; Kim, Jeong Ik;
(Seoul, KR) ; Woo, Kyung Nyung; (Daegu, KR)
; Ki, Joon Seo; (Seoul, KR) ; Moon, Hong Gi;
(Jeonrabukdo, KR) |
Correspondence
Address: |
John S. Egbert
Harrison & Egbert
7th Floor
412 Main Street
Houston
TX
77002
US
|
Assignee: |
LG CABLE LTD.
Seoul
KR
|
Family ID: |
32388281 |
Appl. No.: |
10/720579 |
Filed: |
November 24, 2003 |
Current U.S.
Class: |
205/76 ;
205/291 |
Current CPC
Class: |
H05K 1/09 20130101; C25D
3/38 20130101; C25D 1/04 20130101 |
Class at
Publication: |
205/076 ;
205/291 |
International
Class: |
C25D 003/38; C25D
001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 29, 2002 |
KR |
10-2002-0075411 |
Claims
We claim:
1. In a method for manufacturing an electrodeposited copper foil in
which a rotating drum and an anode plate which is formed of a curve
distanced from the outer surface of the drum by a certain distance
are drowned in an electrolyte, said electrolyte consists of a
sulfuric acid, copper ion and chloride ion, and the
electrodeposited copper foil is deposited on the surface of the
drum as a negative current is applied to the drum, and a positive
current is applied to the anode plate, a method for manufacturing
an electrodeposited copper foil which is characterized in that an
additive which consists of a gelatin of 0.1.about.100 ppm, a
HEC(Hydroxyethyl Cellulose) of 0.05 ppm.about.50 ppm, and a
SPS(bis(sodiumsulfopropyl)disulfide) of 0.05.about.20 ppm is added
to the electrolyte.
2. The method of claim 1, wherein the amount of the addition of the
gelatin is 2.about.5 ppm.
3. The method of claim 1, wherein the amount of the addition of the
HEC is 1.about.3 ppm.
4. The method of claim 1, wherein the amount of the addition of the
SPS is 0.5.about.3 ppm.
5. The method of one among claims 1 through 4, wherein a roughness
of a matte side of the electrodeposited copper foil is larger than
a roughness of a shiny side.
6. The method of one among claims 1 through 4, further comprising a
post-treatment process.
7. The method of claim 6, wherein said post-treatment process is
formed of one or more than one selected from the steps of: a nodule
process for forming a nodule on one side or both sides of the
electrodeposited copper foil for increasing an adhesion with a
resin; a barrier process for preventing a copper from being
diffused into a resin layer; a corrosion resisting process for
preventing an oxidation of the electrodeposited copper foil; and a
silane coupling agent process for enhancing an adhesion reliability
with the resin.
8. The method of either claim 1 or claim 2, wherein a molecular
weight of the gelatin is above 10000.
9. The method of claim 1, wherein said electrolyte is formed of a
sulfuric acid of 50.about.200 g/l, a copper ion of 30.about.150
g/l, and a chloride ion of 200 mg/l.
10. The method of claim 9, wherein a temperature of the electrolyte
is 20.about.80.degree. C.
11. The method of claim 9, wherein a current density of the
electrolyte is 20.about.150 A/dm.sup.2.
12. A low roughness electrodeposited copper foil manufactured by
one method selected from the claims 1 through 4.
13. The foil of claim 12, wherein a roughness of a matte side of
the electrodeposited copper foil is larger than a roughness of a
shiny side.
14. The foil of claim 12, further comprising a post-treatment
process.
15. The foil of claim 14, wherein said post-treatment process is
formed of one or more than one selected from the steps of: a nodule
process for forming a nodule on one side or both sides of the
electrodeposited copper foil for increasing an adhesion with a
resin; a barrier process for preventing a copper from being
diffused into a resin layer; a corrosion resisting process for
preventing an oxidation of the electrodeposited copper foil; and a
silane coupling agent process for enhancing an adhesion reliability
with the resin.
Description
RELATED U.S. APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO MICROFICHE APPENDIX
[0003] Not applicable.
FIELD OF THE INVENTION
[0004] The present invention relates to a method for manufacturing
an electrodeposited copper foil adhered to a prepreg for a
PCB(Printed Circuit Board) and an electrodeposited copper foil
manufactured thereby, and in particular to a method for
manufacturing an electrodeposited copper foil which does not have a
residual copper by decreasing a roughness of a matte side of an
electrodeposited copper foil even when a fine pattern is
formed.
BACKGROUND OF THE INVENTION
[0005] Generally, a PCB is widely used in a home appliance such as
a radio, television, washing machine, VCR, etc., and an industrial
electric/electronic instrument such as a computer, wireless
communication instrument, various controllers, etc. The PCB is
formed of an insulated substrate such as a prepreg of a frame
retardant formed in such a manner that a glass fiber is impregnated
in foil is adhered to an insulation substrate at a high temperature
and pressure, and then the electrodeposited copper foil is etched
based on a circuit design.
[0006] The electrodeposited copper foil adhered to the insulation
substrate is manufactured by the following processes. A raw foil is
manufactured in a copper sulphate solution by a continuous
electrodepositing method. Next, a nodule process is performed with
respect to a raw copper foil for forming a copper nodule for
thereby enhancing an adhesion to an insulation substrate and a
barrier layer is formed on the copper foil surface. Finally, a
corrosion resist chromating process is performed.
[0007] Recently, as an electric/electro instrument is made thin, a
printed circuit for a substrate need have a fine and high intensive
and compact construction. For this, a method for developing a very
low roughness copper foil has been provided.
[0008] In a conventional electrodeposited copper foil manufacturing
method, a first method is to divide an electrolytic section into
two sections and then to enhance a current density of a second
section rather than a first section for thereby obtaining a low
roughness copper foil.
[0009] A super anode is attached to a foil manufacturing apparatus
of the above manufacturing facility. In the case that the super
anode is adapted, it is possible to change the size of a nucleus
when a nucleus is initially generated by adjusting the current
applied to the super anode and the main anode. Therefore, it is
possible to manufacture the low roughness copper foil by accurately
adjusting the size of the initial nucleus. However, it is
impossible to manufacture a low roughness copper foil corresponding
to the recent fine circuit pattern with the above described
method.
[0010] A second method is directed to decreasing the concentration
of a chloride ion in an electrolyte below 1 ppm for thereby
obtaining a low roughness copper foil. However, it is possible to
decrease the concentration of a chloride ion below 1ppm based on
only an experimental condition. In the case that the
electrodeposited copper foil is manufactured, a copper scrap is
generally used as a source material. When the copper scrap is used
for the mass production system, there is no suitable economic
method for preventing a chloride ion generated by a waste electric
wire. Therefore, it is impossible to implement an actual
practicality.
[0011] A third method is directed to obtaining a low roughness
copper foil by mechanically polishing a conventional
electrodeposited copper foil through a buffing method. However, the
above method is needed to have an additional manufacturing
facility. If there is a surplus during the buffing process, a
residual copper may be formed during the manufacture of the
PCB.
[0012] A fourth method is directed to adjusting morphology of a
copper foil by changing an additive added to an electrolyte. In
more detail, the above fourth method is directed to implementing a
low roughness copper foil by adding a low molecular weight
water-soluble cellulose ether, a low molecular weight water-soluble
polyalkylene glycol ether, a low molecular weight water-soluble
polyethyleneimine, and a water soluble sulfonated organic sulfur
compound. In the above method, it is possible to manufacture a low
roughness copper foil by changing only an additive of an
electrolyte without changing or modifying a conventional copper
manufacture apparatus. In addition, a mechanical polishing process
like a buffing process is not needed. It is not needed to manage a
chloride ion at a very low degree. The above method is more
economical compared to the other methods.
[0013] However, since the copper foil manufactured by the above
method has a roughness Rz of a matte side of 3.81 .mu.m, the above
method does not satisfy the demand of the recent low roughness
copper foil.
[0014] A fifth method is directed to manufacturing a low roughness
copper foil using an electrolyte including a small amount of
polyethylene glycol, tin ion, iron ion and a chloride ion of below
0.1 ppm. In the above method, there is a limit for substantially
maintaining the concentration of the chloride ion below 0.1 ppm for
a mass production.
BRIEF SUMMARY OF THE INVENTION
[0015] Accordingly, it is a first object of the present invention
to provide a method for manufacturing a low roughness
electrodeposited copper foil and an electrodeposited copper foil
manufactured by the method which does not need a design change or
modification of a conventional copper manufacture apparatus and
directly uses a source material of a low cost waste electric wire
without using a conventional facility like a mechanical polishing
apparatus and an additional process and is capable of manufacturing
an electrodeposited copper foil having a low roughness by adjusting
the amount of an additive.
[0016] It is a second object of the present invention to provide a
method for manufacturing a low roughness electrodeposited copper
foil and an electrodeposited copper foil manufactured by the same
which are well adapted to an electrode of a lithium ion battery or
copper clad laminates which is used in an electronic instrument
such as a PCB and a flexible circuit substrate, etc.
[0017] To achieve the above objects, in a method for manufacturing
an electrodeposited copper foil in which a rotating drum and an
anode plate formed of a curve distanced from an outer surface of
the drum by a certain distance are drowned in an electrolyte, said
electrolyte consists of a sulfuric acid, copper ion and chloride
ion, and an electrodeposited copper foil is deposited on a surface
of the drum as a negative current is applied to the drum and a
positive current is applied to the anode plate, there is provided a
method for manufacturing an electrodeposited copper foil which is
characterized in that an additive which consists of a gelatin of
0.1.about.100 ppm, a HEC(Hydroxyethyl Cellulose) of 0.05
ppm.about.50 ppm, and a SPS(bis(sodiumsulfopropyl)disulfide) of
0.05.about.20 ppm is added to the electrolyte.
[0018] The amount of the addition of the gelatin is preferably
2.about.5 ppm. The amount of the addition of the HEC is preferably
1.about.3 ppm. The amount of the addition of the SPS is preferably
0.5.about.3 ppm.
[0019] The molecular weight of the gelatin is preferably above
10000.
[0020] There is preferably further provided a post-treatment for
forming a nodule on one surface or both surfaces of the
electrodeposited copper foil.
[0021] A roughness of a matte side of the electrodeposited copper
foil is larger than that of a shiny side.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0022] The present invention will become better understood with
reference to the accompanying drawings which are given only by way
of illustration and thus are not limitative of the present
invention, wherein;
[0023] FIG. 1 is a view illustrating the construction of a copper
manufacture apparatus for describing a method for manufacturing an
electrodeposited copper foil according to the present
invention;
[0024] FIG. 2 is a picture obtained by photographing an
electrodeposited copper foil manufactured according to an
embodiment 1 of the present invention using a SEM; and
[0025] FIG. 3 is a picture obtained by photographing an
electrodeposited copper foil manufactured according to a comparison
example 2 using a SEM.
DETAILED DESCRIPTION OF THE INVENTION
[0026] FIG. 1 is a view illustrating a copper foil manufacture
apparatus for describing a method for manufacturing an
electrodeposited copper foil according to the present
invention.
[0027] As shown in FIG. 1, the copper foil manufacture apparatus is
constructed in such a manner that a rotating drum 100 and a
circular shaped anode plate 200 are spaced apart by a certain
distance. Here, the drum 100 and the anode plate 200 are provided
within a tank 500 having an electrolyte 600.
[0028] Here, a lower portion of the rotation center of the drum 100
is drowned in the electrolyte 600. The anode plate 200 is drowned
in the electrolyte 600 in such a manner that the drowned shape of
the drum 100 corresponds to the drowned shape of the anode plate
200. The negative and positive currents are applied to the drum 100
and the anode plate 200, respectively.
[0029] Preferably, the electrolyte 600 filled in the tank 500
consists of H.sub.2SO.sub.4 of about 50.about.200 g/l, Cu.sup.2+ of
about 30.about.150 g/l, and Cl.sup.- of below about 200 mg/l. The
temperature of the electrolyte 600 is about 20.about.80.degree. C.,
and the current density is about 20.about.150 A/dm.sup.2.
[0030] An electrolytic process is performed between the drum 100
and the anode plate 200, such that an electrodeposited copper foil
400 is deposited on a surface of the drum 100. The electrodeposited
copper foil 400 is rolled up by the roller 300 installed in the
upper right side.
[0031] A certain additive is usually provided into the electrolyte
600 for adjusting a material property of the electrodeposited
copper foil 400 in the above method. In the present invention, the
electrodeposited copper foil 400 having a fine circuit pattern is
manufactured by using a gelatin, and HEC(Hydroxyethyl cellulose),
SPS(bis(sodiumsulfopropyl)disul- fide) as an additive. In addition,
a low roughness electrodeposited copper foil 400 which may be used
as an electrode material of a lithium ion battery is
manufactured.
[0032] The gelatin used as an additive is a kind of a drived
protein and has a molecular weight of above 10000. If the gelatin
having molecular weight below 10000 is used, an interaction between
SPS and HEC is weakened, so that an electrodeposited copper foil
having ununiform roughness and gloss is manufactured. In the case
that the molecular weight of the gelatin is above 10000, it is
possible to manufacture a low roughness copper foil having a
uniform roughness and gloss.
[0033] The amount of the addition of the gelatin is minimum about
0.1 ppm through maximum about 100 ppm. Preferably, the amount range
of the addition of the gelatin is about 1.about.10 ppm. More
preferably, the amount range of the same is about 2.about.5
ppm.
[0034] If the gelatin is added below 0.1 ppm in the electrolyte
600, more delicate initial structure may be obtained, but an
electrodeposited copper foil with high roughness is obtained by
promoting the growth of the copper foil 400. Accordingly, an
electrodeposited copper foil with low roughness cannot be
manufactured. On the other hand, if the gelatin is added above 100
ppm, an electrodeposited copper foil with low roughness may be
obtained, but the characteristic of HTE(High Temperature
Elongation, measured at 180.degree. C.) which is one of the
important characteristics of the copper foil can be
deteriorated.
[0035] The amount of the addition of the HEC is minimum about 0.05
ppm through maximum about 50 ppm. Preferably, the amount range of
the addition of the HEC is about 0.5.about.5 ppm. More preferably,
the amount range of the same is about 1-3 ppm. In the case that the
HEC is added with the SPS and the gelatin in the electrolyte 600,
an electrodeposited copper foil with a lower roughness can be
manufactured by an interaction of the additives.
[0036] If the HEC is added below 0.05 ppm in the electrolyte, a
uniform electrodeposited copper foil may not be manufactured due to
the decrease of the interaction. On the other hand, if the HEC is
added above 50 ppm, protrusion may be extracted from the
electrodeposited copper foil. In the case that copper clad
laminates are produced by the electrodeposited copper foil with
protrusion and then a PCB(Printed Circuit Board) is produced by the
above copper clad laminates, the inferiority of the PCB is
caused.
[0037] The amount of the addition of the SPS is minimum about 0.05
ppm through maximum about 20 ppm. Preferably, the amount range of
the addition of the SPS is about 0.1.about.10 ppm. More peferably,
the amount range of the same is about 0.5.about.3 ppm. The SPS is a
material used as a brightener for an electrodepositing process. In
the case that the SPS is added into the electrolyte 600, it is
possible to decrease the roughness of the electrodeposited copper
foil in accordance with an interaction with the HEC and the
gelatin.
[0038] If the SPS is added by below 0.05 ppm, the ability of the
interaction is decreased, so that an electrodeposited copper foil
400 having ununiform roughness is manufactured. On the other hand,
if the SPS is added by the amount of above 20 ppm, there is not a
certain effect, but the cost is increased.
[0039] Three embodiments for manufacturing an electrodeposited
copper foil 400 in such a manner that the amounts of the gelatin,
HEC, and SPS added to the electrolyte 600 as an additive are
different by the unit of ppm will be described in the
following.
[0040] According to the embodiments of the present invention, the
electrolysis condition is as follows. The electrolyte 600 basically
consists of H.sub.2SO.sub.4 of about 100 g/l, Cu.sup.2+ of about
100 g/l, and Cl.sup.- of below about 30 mg/l. The temperature of
the electrolyte 600 is about 60.degree. C., and the current density
is about 100 A/dm.sup.2.
[0041] The amounts of the additives added to the electrolyte 600
are shown in Table 1.
1 TABLE 1 Gelatin HEC SPS Embodiment 1 2.5 ppm 3 ppm 1.5 ppm
Embodiment 2 3.5 ppm 1 ppm 2.5 ppm Embodiment 3 4.5 ppm 2 ppm 0.5
ppm
[0042] In the following, the comparison example 1 that HEC is not
added as an additive and the comparison example 2 that Thiourea is
newly added without adding HEC and SPS will be described. The
comparison examples are performed for comparing the material
properties of the electrodeposited copper foil 400 which is
manufactured when the additives according to the present invention
are all added with those of the electrodeposited copper foil which
is manufactured when a certain additive among the additives
according to the present invention is not added.
[0043] The electrolysis condition of the electrolyte of the
comparisons except for the components of the additives is the same
as the electrolysis condition of the electrolyte of the above
embodiments of the present invention. The amounts of the additives
added are shown in Table 2.
2TABLE 2 Gelatin HEC SPS Thiourea Comparison example 1 2.5 ppm --
1.5 ppm -- Comparison example 2 3.5 ppm -- -- 0.4 ppm
[0044] FIG. 2 is a picture obtained by photographing an
electrodeposited copper foil manufactured according to an
embodiment 1 of the present invention using a SEM, and FIG. 3 is a
picture obtained by photographing an electrodeposited copper foil
manufactured according to a comparison example 2 using a SEM. As
shown therein, FIGS. 2 and 3 illustrate the pictures of the SEM of
the electrodeposited copper foil manufactured based on the
embodiment 1 of the present invention and the electrodeposited
copper foil manufactured based on the comparison example 2,
respectively, before the post-treatments are performed.
[0045] As shown in FIGS. 2 and 3, it is known that the
electrodeposited copper foil 400 manufactured based on the
embodiment 1 of the present invention has a more smooth surface
compared to the surface of the electrodeposited copper foil
manufactured based on the comparison example 2. The above
consequence represents that the roughness of the surface of the
electrodeposited copper foil 400 manufactured based on the
embodiment 1 of the present invention is relatively lower than that
of the electrodeposited copper foil 400 manufactured based on the
comparison example 2.
[0046] In Table 3, there are a roughness, tensile strength,
elongation, high temperature tensile strength, and high temperature
elongation of the electrodeposited copper foil manufactured based
on each embodiment of the present invention and the
electrodeposited copper foil manufactured based on each comparison
example.
3 TABLE 3 High High temper- Rough- Tensile Elon- temperature ature
ness strength gation tensile strength elonga- Rz(.mu.m)
(kgf/mm.sup.2) (%) (kgf/mm.sup.2) tion(%) Embodiment 1 1.8 33.3
15.9 18.3 16.3 Embodiment 2 1.6 34.6 18.1 18.2 15.1 Embodiment 3
2.1 32.8 16.3 19.1 15.3 Comparison 2.5 34.1 5.8 20.1 8.5 example 1
Comparison 3.5 33.8 8.3 20.3 2.1 example 2
[0047] As shown in Table 3, it is known that the roughness of the
electrodeposited copper foils manufactured according to the
embodiments 1 through 3 are 1.61 .mu.m through 2.1 pm, and the
roughness of the electrodeposited copper foils manufactured
according to the comparison examples 1 through 2 are about 2.5 pm
through 3.5 .mu.m. As a result, it is known that the
electrodeposited copper foils manufactured according to the
preferred embodiments of the present invention have a lower
roughness, respectively, compared to the roughness of the
electrodeposited copper foils manufactured according to the
comparison examples.
[0048] The electrodeposited copper foil manufactured according to
the present invention can be implemented with a conventional
post-treatment for manufacturing the copper clad laminates which is
used for printed circuit substrate.
[0049] As a conventional post-treatment of the electrodeposited
copper foil 400, there are a nodule process adapted to further form
a nodule on one side or both sides of the electrodeposited copper
foil for increasing an adhesion with a resin, a barrier process
adapted to prevent a copper from being diffused into a resin layer,
a corrosion resisting process adapted to prevent an oxidation of a
copper foil, and a silane coupling agent process adapted to enhance
a adhesion reliability when being adhered with a resin.
[0050] In addition, the electrodeposited copper foil 400
manufactured according to the present invention is formed of a
copper clad laminate with an insulation film layer and an adhesive
layer. The copper clad laminate is etched based on a circuit design
and is adapted to manufacture a printed circuit substrate.
[0051] In the method for manufacturing a low roughness
electrodeposited copper foil and an electrodeposited copper foil
manufactured thereby, the amounts of additives cited in each
embodiment are not limited thereto. In the present invention,
various embodiments may be implemented in the addition ranges of
the additives cited in the present invention. The electrodeposited
copper foils 400 having various material properties may be adapted
to the production of the copper clad laminate and the circuit
substrate.
[0052] As the present invention may be embodied in several forms
without departing from the spirit or essential characteristics
thereof, it should also be understood that the above-described
examples are not limited by any of the details of the foregoing
description, unless otherwise specified, but rather should be
construed broadly within its spirit and scope as defined in the
appended claims, and therefore all changes and modifications that
fall within the meets and bounds of the claims, or equivalences of
such meets and bounds are therefore intended to be embraced by the
appended claims.
* * * * *