U.S. patent application number 11/573167 was filed with the patent office on 2007-09-13 for barrier film for flexible copper substrate and sputtering target for forming barrier film.
This patent application is currently assigned to NIPPON MINING & METALS CO., LTD.. Invention is credited to Shuichi Irumata, Yasuhiro Yamakoshi.
Application Number | 20070209547 11/573167 |
Document ID | / |
Family ID | 35839246 |
Filed Date | 2007-09-13 |
United States Patent
Application |
20070209547 |
Kind Code |
A1 |
Irumata; Shuichi ; et
al. |
September 13, 2007 |
Barrier Film For Flexible Copper Substrate And Sputtering Target
For Forming Barrier Film
Abstract
Provided are a barrier film for a flexible copper substrate
comprising a Co--Cr alloy film containing 5 to 30 wt % of Cr and a
balance of unavoidable impurities and Co, having a film thickness
of 3 to 150 nm, and film thickness uniformity of 10% or less at
1.sigma.; and a sputtering target for forming a barrier film
comprising a Co--Cr alloy containing 5 to 30 wt % of Cr and a
balance of unavoidable impurities and Co, wherein the relative
magnetic permeability in the in-plane direction of the sputtered
face is 100 or less. The barrier film for a flexible copper
substrate and the sputtering target for forming such barrier film
have a film thickness that is thin enough to prevent film peeling
in inhibiting the diffusion of copper to a resin film such as
polyimide, is capable of obtaining a sufficient barrier effect even
in a minute wiring pitch, and have barrier characteristics that
will not change even when the temperature rises due to heat
treatment or the like.
Inventors: |
Irumata; Shuichi; (Ibaraki,
JP) ; Yamakoshi; Yasuhiro; (Ibaraki, JP) |
Correspondence
Address: |
HOWSON AND HOWSON
SUITE 210
501 OFFICE CENTER DRIVE
FT WASHINGTON
PA
19034
US
|
Assignee: |
NIPPON MINING & METALS CO.,
LTD.
10-1, Toranomon 2-chome, Minato-ku
Tokyo
JP
1050001
|
Family ID: |
35839246 |
Appl. No.: |
11/573167 |
Filed: |
July 25, 2005 |
PCT Filed: |
July 25, 2005 |
PCT NO: |
PCT/JP05/13548 |
371 Date: |
February 2, 2007 |
Current U.S.
Class: |
106/1.12 |
Current CPC
Class: |
C23C 14/205 20130101;
Y10T 428/1291 20150115; Y10T 428/31721 20150401; C23C 14/3414
20130101; Y10T 428/12715 20150115; C22C 19/07 20130101; Y10T
428/12847 20150115; H05K 1/0346 20130101; Y10T 428/12569 20150115;
H05K 1/0393 20130101; H05K 3/388 20130101; Y10T 428/31681
20150401 |
Class at
Publication: |
106/001.12 |
International
Class: |
C09D 5/00 20060101
C09D005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 10, 2004 |
JP |
2004-232872 |
Claims
1. A barrier film for a flexible copper substrate comprising a
Co--Cr alloy film containing 5 to 30 wt % of Cr and a balance of
unavoidable impurities and Co, having a film thickness of 3 to 150
nm, and film thickness uniformity of 10% or less at 1.sigma..
2. A sputtering target for forming a barrier film comprising a
Co--Cr alloy containing 5 to 30 wt % of Cr and a balance of
unavoidable impurities and Co, wherein the relative magnetic
permeability in the in-plane direction of the sputtered face is 100
or less.
Description
TECHNICAL FIELD
[0001] The present invention relates to a barrier film for a
flexible copper substrate and a sputtering target for forming such
barrier film capable of effectively inhibiting the diffusion of
copper to a resin film such as polyimide.
BACKGROUND ART
[0002] Conventionally, a copper layer is formed on a resin film
such as polyimide, which is to become the base film, upon
manufacturing a flexible copper substrate, Specifically, a copper
seed layer is formed on the polyimide film by sputtering or
electroless deposition, and a thick copper plated layer is formed
thereon. Thereafter, the copper is subject to etching so as to form
a copper circuit pattern.
[0003] The problem here is that the copper formed on the polyimide
film easily diffuses (migrates) in the polyimide film, and causes a
short circuit in the wiring on the circuit board.
[0004] In order to inhibit this kind of diffusion of Cu to the
polyimide film, proposed is a method of forming in advance a
barrier layer for preventing the diffusion of Cu on the polyimide
film, and forming a Cu seed layer and a thick Cu plated layer
thereon.
[0005] As a representative example, there is technology which forms
a Ni--Cr alloy barrier layer (refer to Patent Document 1).
[0006] Nevertheless, when the temperature rises to about 200 to
300.degree. C., diffusion of Cu to the polyimide film can still be
acknowledged. In addition, when the wiring pitch becomes narrower
than 30 .mu.m, it is not possible to prevent diffusion to the
polyimide layer with a conventional barrier layer, and it has
become known that this is not necessarily effective.
[0007] As a means for preventing the foregoing problem, it is
conceivable that the barrier characteristics can be improved by
thickening the conventional barrier layer. Nevertheless, when the
thickness exceeds a certain value, another problem occurs in that
the barrier film would peel from the polyimide film. Therefore,
this method was insufficient to become a fundamental solution.
[0008] As another proposal, suggested is a method of forming a
thermoplastic polyimide layer on a thermosetting polyimide base
film, covering this with a barrier metal formed from at least one
type of metal selected from Ni, Cr, Co and Mo, heating and
fluidizing the thermoplastic resin, and increasing the bonding
strength between the thermoplastic polyimide and the barrier metal
(refer to Patent Document 2).
[0009] Nevertheless, in this case, since the foregoing method does
not fundamentally solve the diffusion of the barrier metal, this
problem still needs to be solved.
[Patent Document 1] Japanese Patent Laid-Open Publication No.
2002-252257
[Patent Document 2] Japanese Patent Laid-Open Publication No.
2002-280684
SUMMARY OF THE INVENTION
[0010] In light of the foregoing problems of conventional
technology, an object of the present invention is to obtain a
barrier film for a flexible copper substrate and a sputtering
target for forming such barrier film. The barrier film for a
flexible copper substrate can inhibit the diffusion of copper to a
resin film such as polyimide. Further, the film thickness is thin
enough to prevent film peeling, and is capable of obtaining a
sufficient barrier effect even in a minute wiring pitch. Moreover,
the barrier characteristics will not change even when the
temperature rises due to heat treatment or the like.
[0011] As a result of intense study, the present inventors
discovered that the foregoing problems can be overcome by using an
alloy having effective barrier characteristics, forming the barrier
film as thin as possible in order to prevent peeling, and improving
the uniformity of the deposited film.
[0012] Based on the foregoing discovery, the present invention
provides: [0013] (1) A barrier film for a flexible copper substrate
comprising a Co--Cr alloy film containing 5 to 30 wt % of Cr and a
balance of unavoidable impurities and Co, having a film thickness
of 3 to 150 nm, and film thickness uniformity of 10% or less at
1.sigma.; and [0014] (2) A sputtering target for forming a barrier
film comprising a Co--Cr alloy containing 5 to 30 wt % of Cr and a
balance of unavoidable impurities and Co, wherein the relative
magnetic permeability in the in-plane direction of the sputtered
face is 100 or less.
[0015] The barrier film for a flexible copper substrate of the
present invention yields superior effects in that it has a film
thickness that is thin enough to prevent film peeling, is capable
of obtaining a sufficient barrier effect even in a minute wiring
pitch, and has barrier characteristics that will not change even
when the temperature rises due to heat treatment or the like. The
present invention yields significant characteristics in that it is
capable of effectively inhibiting the diffusion of copper to a
resin film such as polyimide.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a diagram showing the analysis (AES) of Cu
diffusion in the case of using the Co--Cr alloy barrier film of
Example 1; and
[0017] FIG. 2 is a diagram showing the analysis (AES) of Cu
diffusion in the case of using the Ni--Cr alloy barrier film of
Comparative Example 1.
BEST MODE FOR CARRYING OUT THE INVENTION
[0018] The barrier film for a flexible copper substrate according
to the present invention is a Co--Cr alloy film containing 5 to 30
wt % of Cr and a balance of unavoidable impurities and Co.
[0019] In the film composition, if the Cr content is less than 5 wt
%, the barrier properties will be insufficient, and there will be
no advantage over conventional barrier films. Further, if the Cr
content exceeds 30 wt %, it would be impractical since the barrier
film will interfere with the etching of the Cu layer to form a
circuit, and much time will be required in eliminating such barrier
film. Accordingly, the Cr content shall be within the foregoing
range.
[0020] The film thickness of the barrier film for a flexible copper
substrate of the present invention shall be 3 to 150 nm. If the
film thickness is less than 3 nm, sufficient barrier properties
cannot be obtained. Further, if the film thickness exceeds 150 nm,
the film will easily peel. Thus, the film thickness shall be within
the foregoing range.
[0021] The film thickness of the barrier film for a flexible copper
substrate of the present invention shall have a film thickness
uniformity of 10% or less at 1.sigma.. When the film thickness
uniformity (1.sigma.) exceeds 10%, there is a problem in that,
during etching process, the portion where the barrier film is thin
will be etched broader than the portion to be removed when etching
is performed until the thick portion of the barrier film is to be
removed, and the linewidth of such portion will become narrow. As a
result, the durability of the actual device will deteriorate.
Accordingly, the film thickness uniformity (1.sigma.) shall be 10%
or less.
[0022] The sputtering target for forming a barrier film according
to the present invention employs a Co--Cr alloy target containing 5
to 30 wt % of Cr and a balance of unavoidable impurities and Co.
The composition of the Co--Cr alloy target of the present invention
is directly reflected to the composition of the barrier film. In
other words, when the Cr content in the target composition is less
than 5 wt %, it is not possible to deposit a Co alloy film having 5
wt % or more of Cr.
[0023] Meanwhile, when the Cr content exceeds 30 wt %, it is not
possible to deposit a Co alloy film having 30% or less of Cr.
Therefore, the composition of the Co--Cr alloy target shall be
within the foregoing range.
[0024] Moreover, with the sputtering target for forming a barrier
film according to the present invention, the relative magnetic
permeability in the in-plane direction of the sputtered face shall
be 100 or less. If the relative magnetic permeability exceeds 100,
the film thickness uniformity of the sputtered film will exceed 10%
at 1.sigma..
[0025] It is desirable that the Co--Cr alloy target of the present
invention has an average grain size of 500 .mu.m or less,
preferably 100 .mu.m or less. This is because if the average grain
size exceeds 500 .mu.m, the generation of particles will increase,
a film defect known as pinholes will increase, and the production
yield will deteriorate.
[0026] Further, with the Co--Cr alloy target of the present
invention, it is desirable that the variation of the average grain
size in the target is 30% or less. This is because if the variation
of the average grain size exceeds 30%, the film thickness
uniformity of the film subject to sputtering deposition could
exceed 10% at 1.sigma..
[0027] Upon manufacturing the target of the present invention, it
is desirable to process the target board with a combination of hot
forging and rolling at 800 to 1370.degree. C.
[0028] Further, after performing the foregoing hot forging and
rolling, it is desirable to perform heat treatment in the
atmosphere, in a vacuum, or under an inert gas atmosphere at a
holding temperature of 300 to 960.degree. C.
[0029] The heat treated plate obtained as described above is
machined into a target shape, and the average roughness (Ra) of the
sputtering surface is made to be 0.01 to 5 .mu.m.
[0030] Further, it is desirable that the non-sputtering surface
such as the target side or backing plate; that is, the portions to
which the sputtered substances adhere, should be roughened such
that the average roughness (Ra) of the surface becomes 1 to 50
.mu.m by bead blasting, etching or spraying so as to prevent the
peeling of the deposited film. This is because substances that peel
and float in the sputtering atmosphere cause the generation of
particles on the substrate.
[0031] It is desirable that the target of the present invention is
bonded to a backing plate formed from an Al alloy, Cu, Cu alloy,
Ti, or Ti alloy by way of metallic bonding such as brazing,
diffusion bonding or friction pressure welding so that it can
endure high power sputtering.
[0032] Further, as impurities contained in the target, it is
desirable that the concentrations of Na and K are respectively 5
ppm or less (hereinafter, ppm represents wtppm), the concentrations
of U and Th are respectively 0.05 ppm or less, the total amount of
metallic elements except principal elements and added elements is
0.5 wt % or less, and the oxygen concentration is 0.5 wt % or
less.
EXAMPLES
[0033] The present invention is now explained in further detail
with reference to the Examples. These Examples are merely
illustrative, and the present invention shall never be limited
thereby. In other words, the present invention shall only be
limited by the scope of the present invention, and shall include
the various modifications other than the Examples of this
invention.
Example 1
[0034] The composition of Co-20 wt % Cr was subject to melting and
casting to prepare a Co--Cr ingot. This ingot was subject to hot
forging and hot rolling at 1100.degree. C., cooled, and thereafter
subject to heat treatment at 500.degree. C. for 2 hours and
machined into a target. The grain size of this target was 280
.mu.m. This target was further subject to finishing so that the
average surface roughness Ra became 0.14 .mu.m.
[0035] The Cr concentration of the target was 19.1 wt %, impurity
components were 0.2 ppm of Na, 0.1 ppm of K, 0.02 ppm of U, 0.03
ppm of Th, the total content of metal components was 470 ppm, and
the oxygen content was 10 ppm.
[0036] This target was bonded to the backing plate with indium, and
the target side and the backing plate near the target were subject
to bead blasting and coarsened until the Ra became 7.5 .mu.m.
[0037] This target was used to prepare a barrier layer having a
film thickness of 140 nm. As a result of analyzing the composition
of the respective added components of this barrier layer, there was
18.3 wt % of Cr, and coincided with the composition with a slightly
low content of Cr. The film thickness of this barrier layer was
measured with a 49-point measurement, and the film thickness
uniformity was 7.2% at 1.sigma..
[0038] Cu layer of 200 nm thickness was deposited on this barrier
layer with sputtering.
[0039] With respect to this Cu/Co--Cr laminated film, a depth
profile of a sample only subject to the foregoing deposition and a
sample that was further subject to heat treatment in a vacuum at
300.degree. C..times.2 hours was taken with AES (Auger electron
spectroscopy), and the diffusion of Cu to the barrier layer was
evaluated.
[0040] FIG. 1 shows the results of depth profile with AES. With the
barrier film formed from Co--Cr that were subject to heat treatment
at 300.degree. C., the Cu profile was the same profile as the
sample that was not subject to heat treatment, and diffusion to the
barrier layer could not be acknowledged.
Comparative Example 1
[0041] A material having a composition of Ni-20 wt % Cr, which is a
conventional barrier material, was subject to melting and casting
to prepare a Ni--Cr ingot. This ingot was subject to hot forging
and hot rolling at 1100.degree. C., cooled, and thereafter subject
to heat treatment at 500.degree. C. for 2 hours and processed into
a target.
[0042] The grain size of the target was 300 .mu.m, and the surface
roughness was subject to finishing so that the Ra became 0.15
.mu.m. The Cr concentration in the target was 19.7 wt %, impurity
components were 0.1 ppm of Na, 0.3 ppm of K, 0.02 ppm of U, 0.04
ppm of Th, the total content of metal components was 510 ppm, and
the oxygen content was 10 ppm.
[0043] This target was bonded to the backing plate with indium, and
the target side and the backing plate near the target were subject
to bead blasting and roughened until the Ra became 7.0 .mu.m. The
relative magnetic permeability in the in-plane direction of the
target was 130.
[0044] Using this target, a barrier film having a film thickness of
140 nm was formed on a SiO.sub.2 substrate so that the barrier film
would not peel.
[0045] As a result of the composition analysis of the respective
added components of this barrier layer, there was 18.5 wt % of Cr
and the composition of the layer is slightly lower than that of the
target. The film thickness of this barrier layer was measured at
49-point, and the film thickness uniformity was 7.4% at
1.sigma..
[0046] A 200 nm Cu film was deposited on this barrier layer with
sputtering. For this Cu/Ni--Cr film, a profile in the depth
direction of a sample only subject to the foregoing deposition and
a sample that was further subject to heat treatment in a vacuum at
300.degree. C..times.2 hours were analyzed by AES (Auger electron
spectroscopy), and the diffusion of Cu to the barrier layer was
evaluated. FIG. 2 shows the results of AES.
[0047] The Cu of the sample that was subject to heat treatment at
300.degree. C. was diffused deeper into the barrier layer in
comparison to the sample that was not subject to heat treatment. In
other words, it has been discovered that the function as a barrier
layer is inferior.
Example 2 to 8
[0048] A target was prepared with the same manufacturing method as
Example 1, and such target having an alloy composition and relative
magnetic permeability within the range of the present invention
shown in Table 1 was used to form a barrier layer having a film
thickness of 10 nm on a polyimide sheet having a thickness of 38
.mu.m.
[0049] Further, the composition (wt %) of the respective added
components of the barrier layer, the film thickness (nm) of the
barrier layer, the film thickness uniformity (%) that measured the
film thickness of the barrier layer at a 49-point, and the
endurance test (hours) are similarly shown in Table 1. The film
composition (wt %), film thickness (nm), and film thickness
uniformity (%) of the barrier film of Examples 2 to 8 were all
within the range of the present invention.
[0050] Further, a 20 nm Cu seed layer was deposited on this barrier
layer with sputtering, and this was further subject to
electroplating so as to form a Cu layer of 8 .mu.m. An endurance
test was performed to a wiring pattern prepared with a 30 .mu.m
pitch (linewidth 15 .mu.m, distance between wires 15 .mu.m) by
applying a +60V voltage, and retaining the wiring pattern in an
atmosphere having a temperature of 85.degree. C. and humidity of
85%. The results are similarly shown in Table 1.
[0051] As a result of the above, Examples 2 to 8 did not cause a
short circuit in its wires.
Comparative Example 2
[0052] The same target as Comparative Example 1 shown in Table 1
was used, and a Ni--Cr barrier layer having a film thickness of 10
nm was formed on a polyimide sheet having a thickness of 38
.mu.m.
[0053] Further, the composition (wt %) of the respective added
components of the barrier layer, the film thickness (nm) of the
barrier layer, the film thickness uniformity (%) that measured the
film thickness of the barrier layer at a 49-point, and the
endurance test (hours) are similarly shown in Table 1.
[0054] The alloy component (Ni--Cr) of the barrier film of
Comparative Example 2 is out of the range of the present
invention.
[0055] Moreover, a 20 nm Cu seed layer was deposited on this
barrier layer by sputtering, and this was further subject to
electroplating so as to form a Cu layer of 8 .mu.m. An endurance
test was performed to a wiring pattern prepared with a 30 .mu.m
pitch (linewidth 15 .mu.m, distance between wires 15 .mu.m) by
applying a +60V voltage, and retaining the wiring pattern in an
atmosphere having a temperature of 85.degree. C. and humidity of
85%. The results are similarly shown in Table 1.
[0056] As a result of performing the foregoing endurance test,
although Comparative Example 2 lasted for 350 hours, it caused a
short circuit in the wires thereafter.
Comparative Example 3
[0057] A target was prepared with the same manufacturing method as
Example 1, and a target having an alloy composition outside the
range of the present invention (Cr content is less than the present
invention) as shown in Table 1 was used to form a Co--Cr barrier
layer having a film thickness of 10 nm on a polyimide sheet having
a thickness of 38 .mu.m.
[0058] Further, the composition (wt %) of the respective added
components of the barrier layer, the film thickness (nm) of the
barrier layer, the film thickness uniformity (%) that measured the
film thickness of the barrier layer at a 49-point, and the
endurance test (hours) are similarly shown in Table 1.
[0059] The film composition (3.5 wt % of Cr) of the barrier film of
Comparative Example 3 was less than the Cr content (5 to 30 wt %)
of the film according to the present invention.
[0060] Moreover, a 20 nm Cu seed layer was deposited on this
barrier layer, and this was further subject to electrodeposition so
as to form a Cu layer of 8 .mu.m. An endurance test was performed
to a wiring pattern prepared with a 30 .mu.m pitch (linewidth 15
.mu.m, distance between wires 15 .mu.m) by applying a +60V voltage,
and retaining the wiring pattern in an atmosphere having a
temperature of 85.degree. C. and humidity of 85%. The results are
similarly shown in Table 1.
[0061] As a result of performing the foregoing endurance test,
although Comparative Example 3 lasted for 210 hours, it caused a
short circuit in the wires thereafter.
Comparative Example 4
[0062] A target was prepared with the same manufacturing method as
Example 1, and a target having an alloy composition outside the
range of the present invention (Cr content is more than the present
invention) as shown in Table 1 was used to form a Co--Cr barrier
layer having a film thickness of 10 nm on a polyimide sheet having
a thickness of 38 .mu.m.
[0063] Further, the composition (wt %) of the respective added
components of the barrier layer, the film thickness (nm) of the
barrier layer, the film thickness uniformity (%) that measured the
film thickness of the barrier layer at a 49-point, and the
endurance test (hours) are similarly shown in Table 1.
[0064] The film composition (33.1 wt % of Cr) of the barrier film
of Comparative Example 4 was less than the Cr content (5 to 30 wt
%) of the film according to the present invention.
[0065] Moreover, a 20 nm Cu seed layer was deposited on this
barrier layer, and this was further subject to electroplating so as
to form a Cu layer of 8 .mu.m. Although an attempt was made to
prepare a wiring pattern prepared with a 30 .mu.m pitch (linewidth
15 .mu.m, distance between wires 15 .mu.m), the Co--Cr layer
remained since it could not be etched, and a pattern could not be
formed.
Comparative Example 5
[0066] A target was prepared with the same manufacturing method as
Example 1, and a target having a relative magnetic permeability
outside the range of the present invention as shown in Table 1 was
used to form a Co--Cr barrier layer having a film thickness of 10
nm on a polyimide sheet having a thickness of 38 .mu.m.
[0067] Further, the composition (wt %) of the respective added
components of the barrier layer, the film thickness (nm) of the
barrier layer, the film thickness uniformity (%) that measured the
film thickness of the barrier layer at a 49-point, and the
endurance test (hours) are similarly shown in Table 1.
[0068] Moreover, a 20 nm Cu seed layer was deposited on this
barrier layer, and this was further subject to electroplating so as
to form a Cu layer of 8 .mu.m. An endurance test was performed to a
wiring pattern prepared with a 30 .mu.m pitch (linewidth 15 .mu.m,
distance between wires 15 .mu.m) by applying a +60V voltage, and
retaining the wiring pattern in an atmosphere having a temperature
of 85.degree. C. and humidity of 85%. The results are similarly
shown in Table 1.
[0069] As a result of performing the foregoing endurance test,
although Comparative Example 5 lasted for 470 hours, it caused a
short circuit in the wires thereafter. In addition, the film
thickness uniformity was also considerably inferior.
Comparative Example 6
[0070] A target was prepared with the same manufacturing method as
Example 1, and a target shown in Table 1 was used to perform
sputtering, and a Co--Cr barrier layer having a film thickness of
2.5 nm which is out of the range of the present invention (thinner
than the present invention) was formed on a polyimide sheet having
a thickness of 38 .mu.m.
[0071] Further, the composition (wt %) of the respective added
components of the barrier layer, the film thickness (nm) of the
barrier layer, the film thickness uniformity (%) that measured the
film thickness of the barrier layer at a 49-point, and the
endurance test (hours) are similarly shown in Table 1.
[0072] Moreover, an endurance test was performed to a wiring
pattern prepared with a 30 .mu.m pitch (linewidth 15 .mu.m,
distance between wires 15 .mu.m) by applying a +60V voltage, and
retaining the wiring pattern in an atmosphere having a temperature
of 85.degree. C. and humidity of 85%. The results are similarly
shown in Table 1.
[0073] As a result of performing the foregoing endurance test,
although Comparative Example 6 lasted for 390 hours, it caused a
short circuit in the wires thereafter. It has become clear that
when the film thickness of the barrier layer is insufficient,
diffusion of Cu to the polyimide sheet will occur, resulting in no
durability.
Comparative Example 7
[0074] A target was prepared with the same manufacturing method as
Example 1, and, under the condition that the film thickness of the
barrier layer is outside the range of the present invention as
shown in Table 1, a Co--Cr barrier layer having a film thickness of
180 nm which is out of the range of the present invention (thicker
than the present invention) was formed on a polyimide sheet having
a thickness of 38 .mu.m.
[0075] The composition of the respective added components of the
barrier layer and the film thickness (nm) of the barrier layer are
similarly shown in Table 1. Nevertheless, since the barrier layer
peeled, it was impossible to perform subsequent measurements.
Accordingly, it has become clear that excess film thickness of the
barrier layer is inappropriate. TABLE-US-00001 Relative Magnetic
Target Permeability of Film Composition Film Thickness of
Uniformity of Film Endurance Test Composition Target [wt %] Barrier
Layer [nm] Thickness [%] [Hours] Example 2 Co-19.1 wt % Cr 30 18.3
10 6.5 >1000 Example 3 Co-19.1 wt % Cr 30 18.1 3 7 >1000
Example 4 Co-19.1 wt % Cr 30 18.1 30 6.1 >1000 Example 5 Co-19.1
wt % Cr 30 18.5 140 6.8 >1000 Example 6 Co-4.5 wt % Cr 25 5.2 10
8.9 >1000 Example 7 Co-30.0 wt % Cr 32 29.8 10 7.2 >1000
Example 8 Co-22.3 wt % Cr 70 21.3 10 8.2 >1000 Comparative
Ni-18.5 wt % Cr -- 18.1 10 7.6 350 Example 2 Comparative Co-3.5 wt
% Cr -- 4.2 10 8.9 210 Example 3 Comparative Co-37.5 wt % Cr --
33.1 10 10.2 Defective Example 4 Patterning Comparative Co-22.1 wt
% Cr 120 21.9 10 15.3 470 Example 5 Comparative Co-19.1 wt % Cr 30
18.2 2.5 6.3 390 Example 6 Comparative Co-19.1 wt % Cr 30 18.3 180
Film Peeling N/A Example 7
INDUSTRIAL APPLICABILITY
[0076] The present invention yields superior effects in that it is
capable of obtaining sufficient barrier effects even in a fine
wiring pitch, and has barrier characteristics that will not change
even when the temperature increases due to heat treatment or the
like. Accordingly, the present invention is effective as a barrier
film for a flexible copper substrate since it possesses superior
barrier characteristics against the diffusion of copper to a resin
film such as polyimide.
* * * * *