U.S. patent application number 17/289582 was filed with the patent office on 2021-12-23 for metal clad laminated plate and method for manufacturing metal clad laminated plate.
This patent application is currently assigned to Panasonic Intellectual Property Management Co., Ltd.. The applicant listed for this patent is Panasonic Intellectual Property Management Co., Ltd.. Invention is credited to Yusuke ITO, Kiyotaka KOMORI, Masaya KOYAMA, Yoshinori MATSUZAKI, Hiroaki TAKAHASHI.
Application Number | 20210400810 17/289582 |
Document ID | / |
Family ID | 1000005878611 |
Filed Date | 2021-12-23 |
United States Patent
Application |
20210400810 |
Kind Code |
A1 |
KOYAMA; Masaya ; et
al. |
December 23, 2021 |
METAL CLAD LAMINATED PLATE AND METHOD FOR MANUFACTURING METAL CLAD
LAMINATED PLATE
Abstract
A metal clad laminated plate is a metal clad laminated plate
including: an insulating layer containing a liquid crystal polymer;
and a metal foil lying on the insulating layer. The metal foil has
a surface lying on the insulating layer. The surface has a mean
width of profile elements (RSm) of greater than or equal to 10
.mu.m and less than or equal to 65 .mu.m. The mean width is
calculated from a roughness curve obtained from a cross section of
the metal clad laminated plate. The metal clad laminated plate has
a plate thickness accuracy of less than .+-.20%. Pull strength of
the metal foil from the insulating layer is greater than or equal
to 0.8 N/mm.
Inventors: |
KOYAMA; Masaya; (Mie,
JP) ; ITO; Yusuke; (Mie, JP) ; MATSUZAKI;
Yoshinori; (Mie, JP) ; KOMORI; Kiyotaka; (Mie,
JP) ; TAKAHASHI; Hiroaki; (Mie, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Intellectual Property Management Co., Ltd. |
Osaka |
|
JP |
|
|
Assignee: |
Panasonic Intellectual Property
Management Co., Ltd.
Osaka
JP
|
Family ID: |
1000005878611 |
Appl. No.: |
17/289582 |
Filed: |
October 25, 2019 |
PCT Filed: |
October 25, 2019 |
PCT NO: |
PCT/JP2019/042051 |
371 Date: |
April 28, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 2250/40 20130101;
B32B 37/06 20130101; B32B 2250/03 20130101; B32B 2307/734 20130101;
H05K 1/05 20130101; B32B 2307/206 20130101; B32B 2307/748 20130101;
B32B 37/1027 20130101; B32B 2305/55 20130101; B32B 2307/538
20130101; B32B 2457/08 20130101; B32B 15/08 20130101 |
International
Class: |
H05K 1/05 20060101
H05K001/05; B32B 15/08 20060101 B32B015/08; B32B 37/06 20060101
B32B037/06; B32B 37/10 20060101 B32B037/10 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 29, 2018 |
JP |
2018-203324 |
Claims
1. A metal clad laminated plate, comprising: an insulating layer
containing a liquid crystal polymer; and a metal foil lying on the
insulating layer, the metal foil having a surface lying on the
insulating layer, the surface having a mean width of profile
elements (RSm) of greater than or equal to 10 .mu.m and less than
or equal to 65 .mu.m, the mean width being calculated from a
roughness curve obtained from a cross section of the metal clad
laminated plate, the metal clad laminated plate having a plate
thickness accuracy of less than .+-.20%, pull strength of the metal
foil from the insulating layer being greater than or equal to 0.8
N/mm.
2. The metal clad laminated plate of claim 1, ten-point average
roughness (Rzjis) calculated from the roughness curve is greater
than or equal to 0.5 .mu.m and less than or equal to 3 .mu.m.
3. The metal clad laminated plate of claim 1, wherein the number of
voids which appear between the metal foil and the insulating layer
in the cross section is three or less per 10 .mu.m in length in a
direction orthogonal to a direction in which the metal foil and the
insulating layer face each other.
4. The metal clad laminated plate of claim 1, wherein a plate
thickness accuracy of the metal clad laminated plate is less than
or equal to .+-.10%.
5. The metal clad laminated plate of claim 1, wherein a dimensional
stability, defined in IPC-TM650 No. 2.2.4, of the metal clad
laminated plate is less than or equal to .+-.0.1%.
6. The metal clad laminated plate of claim 1, wherein the liquid
crystal polymer has a melting point of higher than or equal to
300.degree. C. and lower than or equal to 345.degree. C.
7. A method for manufacturing the metal clad laminated plate of
claim 1, the method comprising: hot pressing a laminated body by a
double belt press method, the laminated body including an
insulating film containing the liquid crystal polymer and the metal
foil lying on the insulating film.
8. The method of claim 7, wherein in the hot pressing of the
laminated body, a highest heating temperature is higher than or
equal to a temperature lower than a melting point of the insulating
film by 5.degree. C. and is lower than or equal to a temperature
higher than the melting point by 20.degree. C., and the highest
heating temperature is maintained for longer than or equal to 20
seconds and shorter than or equal to 120 seconds.
9. The metal clad laminated plate of claim 2, wherein the number of
voids which appear between the metal foil and the insulating layer
in the cross section is three or less per 10 .mu.m in length in a
direction orthogonal to a direction in which the metal foil and the
insulating layer face each other.
10. The metal clad laminated plate of claim 2, wherein a plate
thickness accuracy of the metal clad laminated plate is less than
or equal to .+-.10%.
11. The metal clad laminated plate of claim 2, wherein a
dimensional stability, defined in IPC-TM650 No. 2.2.4, of the metal
clad laminated plate is less than or equal to .+-.0.1%.
12. The metal clad laminated plate of claim 2, wherein the liquid
crystal polymer has a melting point of higher than or equal to
300.degree. C. and lower than or equal to 345.degree. C.
13. The metal clad laminated plate of claim 3, wherein a plate
thickness accuracy of the metal clad laminated plate is less than
or equal to .+-.10%.
14. The metal clad laminated plate of claim 3, wherein a
dimensional stability, defined in IPC-TM650 No. 2.2.4, of the metal
clad laminated plate is less than or equal to .+-.0.1%.
15. The metal clad laminated plate of claim 3, wherein the liquid
crystal polymer has a melting point of higher than or equal to
300.degree. C. and lower than or equal to 345.degree. C.
16. The metal clad laminated plate of claim 4, wherein a
dimensional stability, defined in IPC-TM650 No. 2.2.4, of the metal
clad laminated plate is less than or equal to .+-.0.1%.
17. The metal clad laminated plate of claim 4, wherein the liquid
crystal polymer has a melting point of higher than or equal to
300.degree. C. and lower than or equal to 345.degree. C.
18. The metal clad laminated plate of claim 5, wherein the liquid
crystal polymer has a melting point of higher than or equal to
300.degree. C. and lower than or equal to 345.degree. C.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a metal clad laminated
plate and a method for manufacturing the metal clad laminated
plate.
BACKGROUND ART
[0002] Patent Literature 1 discloses a laminate (a metal clad
laminated plate) for a flexible printed wiring board. The metal
clad laminated plate is manufactured by hot press molding of an
insulating film and a metal foil stacked on one another. Thus, the
insulating film is welded to the metal foil, and therefore, an
insulating layer including the insulating film is in close contact
with the metal foil.
[0003] The laminate disclosed in Patent Literature 1, however,
often requires an increased heating temperature, an increased
welding pressure, or the like when the metal foil is welded to the
insulating film in order to increase adhesive strength between the
insulating layer and the metal foil (the pull strength of the metal
foil from the insulating layer). Therefore, the metal clad
laminated plate, which is an end product, may difficultly have a
preferred plate thickness accuracy.
CITATION LIST
Patent Literature
[0004] Patent Literature 1: JP 2010-221694 A
SUMMARY OF INVENTION
[0005] It is an object of the present disclosure to provide a metal
clad laminated plate having a preferred plate thickness accuracy
and preferred pull strength and a method for manufacturing the
metal clad laminated plate.
[0006] An aspect of the present disclosure is a metal clad
laminated plate including: an insulating layer containing a liquid
crystal polymer; and a metal foil lying on the insulating layer.
The metal foil has a surface lying on the insulating layer. The
surface has a mean width of profile elements (RSm) of greater than
or equal to 10 .mu.m and less than or equal to 65 .mu.m. The mean
width is calculated from a roughness curve obtained from a cross
section of the metal clad laminated plate. The metal clad laminated
plate has a plate thickness accuracy of less than .+-.20%. Pull
strength of the metal foil from the insulating layer is greater
than or equal to 0.8 N/mm.
[0007] A method for manufacturing a metal clad laminated plate of
an aspect of the present disclosure is a method for manufacturing
the metal clad laminated plate. The method includes hot pressing a
laminated body by a double belt press method. The laminated body
includes the insulating film containing the liquid crystal polymer
and the metal foil on the insulating film.
[0008] The present disclosure provides a metal clad laminated plate
having a preferred plate thickness accuracy and preferred pull
strength.
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is sectional view schematically illustrating an
example of a metal clad laminated plate according to an
embodiment;
[0010] FIG. 2 is a photograph of a cross section of part of the
metal clad laminated plate according to the embodiment;
[0011] FIG. 3 is a view illustrating the metal clad laminated plate
according to the embodiment;
[0012] FIG. 4 is a photograph of a cross section of part of a metal
clad laminated plate of a second comparative example;
[0013] FIG. 5 is a view illustrating a method for manufacturing the
metal clad laminated plate according to the embodiment; and
[0014] FIG. 6 is a view illustrating the method.
DESCRIPTION OF EMBODIMENTS
[0015] An embodiment of the present disclosure will be described
below.
[0016] <Metal Clad Laminated Plate>
[0017] First, a metal clad laminated plate 1 according to an
embodiment will be described with reference to FIGS. 1 to 4.
[0018] As illustrated in FIG. 1, the metal clad laminated plate 1
includes an insulating layer 21 and metal foils 3. The insulating
layer 21 contains a liquid crystal polymer. The metal foils 3 lie
on the insulating layer 21. The pull strength of each metal foil 3
from the insulating layer 21 is greater than or equal to 0.8 N/mm,
and the metal clad laminated plate 1 has a plate thickness accuracy
of less than .+-.20%.
[0019] Saying that the plate thickness accuracy is less than
.+-.20% specifically means that a maximum thickness is less than
T.times.1.20 and a minimum thickness is greater than T.times.0.8,
where T is the average thickness of the metal clad laminated plate
1. Thus, the metal clad laminated plate 1 can have a uniform
thickness, and a printed wiring board formed of the metal clad
laminated plate 1 can have preferred high-frequency transmission
characteristics. The plate thickness accuracy of the metal clad
laminated plate 1 is preferably less than or equal to .+-.10%, that
is, the maximum thickness is less than T.times.1.10 and the minimum
thickness is greater than T.times.0.9.
[0020] The maximum thickness and the minimum thickness of the metal
clad laminated plate 1 are obtained by, for example, the following
method. First, thicknesses of the metal clad laminated plate 1 are
measured at arbitrary ten points of the metal clad laminated plate
1. Then, a maximum value and a minimum value of the thicknesses at
the ten points are respectively defined as the maximum thickness
and the minimum thickness. Further, an average value is calculated
from the thicknesses at the ten points, thereby obtaining the
average thickness of the metal clad laminated plate 1. The average
thickness of the metal clad laminated plate 1 is preferably,
greater than or equal to 25 .mu.m and less than or equal to 300
.mu.m.
[0021] Moreover, each metal foil 3 has a surface which lies on the
insulating layer 21 and which has a mean width of profile elements
(RSm) of greater than or equal to 10 .mu.m and less than or equal
to 65 .mu.m. The mean width of the profile elements (RSm) is
derived from a shape of a surface, in contact with the insulating
layer 21, of the metal foil 3, the surface appearing in a cross
section of the metal clad laminated plate 1. This cross section is
parallel to a direction in which the metal foil 3 lies on the
insulating layer 21, and the cross section has a length of 10 .mu.m
in a direction orthogonal to the direction in which the metal foil
3 lies on the insulating layer 21.
[0022] Specifically, an image of the cross section of the metal
clad laminated plate 1 as illustrated in FIG. 2 is captured at
first, where the cross section has a length b of 10 .mu.m. From the
shape, which appears in the cross section and which is the shape of
the surface, which is in contact with the insulating layer 21, of
the metal foil 3, a roughness curve c as illustrated in FIG. 3 is
obtained. The roughness curve c is a projection line that appears
in the cross section when in the cross section of FIG. 2, for
example, vertically projecting a virtual straight line toward the
surface, which is in contact with the insulating layer 21 in the
cross section, of the metal foil 3. The virtual straight line is
parallel to a direction orthogonal to a direction in which the
metal foil 3 and the insulating layer 21 face each other. The
virtual straight line extends along the cross section. The mean
width of profile elements (RSm) is calculated from the roughness
curve c in accordance with Japanese Industrial Standards (JIS) B
0601:2001. Note that the length a sown in FIG. 3 is 10 .mu.m
similarly to the length b of FIG. 2.
[0023] The mean width of the profile elements (RSm) of greater than
or equal to 10 .mu.m makes easy engagement of the insulating layer
21 and the metal foil 3 with each other. This can increase the
adhesiveness (pull strength) between the insulating layer 21 and
the metal foil 3. Moreover, the mean width of profile elements
(RSm) of less than or equal to 65 .mu.m makes voids less likely to
be formed between the insulating layer 21 and the metal foil 3.
Thus, impairment of the adhesiveness due to the voids is hardly
caused, and the metal clad laminated plate 1 easily obtains a
preferred plate thickness accuracy. In addition, the mean width of
profile elements (RSm) of greater than or equal to 10 .mu.m and
less than or equal to 65 .mu.m easily imparts preferred
high-frequency transmission characteristics to the printed wiring
board formed of the metal clad laminated plate 1.
[0024] In the metal clad laminated plate 1 according to the present
embodiment, a ten-point average roughness (Rzjis) calculated from
the roughness curve c as illustrated in FIG. 3 is preferably
greater than or equal to 0.5 .mu.m and less than or equal to 3 This
makes easier the engagement of the insulating layer 21 and the
metal foil 3 with each other and further reduces voids formed
between the insulating layer 21 and the metal foil 3. This can
increase the adhesiveness (pull strength) between the insulating
layer 21 and the metal foil 3. The ten-point average roughness
(Rzjis) is calculated in accordance with JIS B 0601:2001.
[0025] Moreover, in the metal clad laminated plate 1, an improved
dimensional stability is obtained. The dimensional stability is
calculated in accordance with IPC-TM650 No. 2.2.4 Method C. The
dimensional stability thus obtained is preferably less than or
equal to .+-.0.1%. Such an improved dimensional stability results
from reduced interior stress in the insulating layer 21. Thus, when
a printed wiring board (referred to as a first wiring plate) formed
of the metal clad laminated plate 1 is laminated with another
printed wiring board (referred to as a second wiring plate)
including an insulating layer and a conductor wire to provide a
multilayer printed wiring board, a conductor wire on the first
wiring plate and the conductor wire on the second wiring plate are
less likely to be shifted from each other. Thus, when a through
hole through which the conductor wires are to be connected is
formed in the multilayer printed wiring board, the through hole is
also less likely to be positionally shifted from each of the
conductor wires.
[0026] In the present embodiment, the metal foil 3 is at least a
metal film applicable to the metal clad laminated plate 1. The
metal foil 3 is, for example, a copper foil. Moreover, the metal
foil 3 has a thickness of, for example, greater than or equal to 6
.mu.m and less than or equal to 70 .mu.m.
[0027] When the metal foil 3 is a copper foil, examples of the
copper foil include an electrolytic copper foil and a rolled copper
foil.
[0028] Moreover, the insulating layer 21 contains a liquid crystal
polymer as described above. The liquid crystal polymer preferably
has a melting point of higher than or equal to 300.degree. C. and
lower than or equal to 345.degree. C. The melting point of the
liquid crystal polymer is obtained by measuring the melting point
of an insulating film 2 which will be described later by, for
example, differential scanning calorimetry (DSC).
[0029] Examples of the liquid crystal polymer includes: a
polyarylate-based liquid crystal polymer; a copolymer including
wholly aromatic polyester, semi-rigidity aromatic polyester,
polyester amide, aromatic, or aliphatic dihydroxy compound as a raw
material; a copolymer including aromatic or aliphatic dicarboxylic
acid as a raw material; a copolymer including aromatic hydroxy
carboxylic acid as a raw material; a copolymer including aromatic
diamine as a raw material; and a copolymer including aromatic
hydroxy amine or aromatic amino carboxylic acid as a raw material.
The liquid crystal polymer contains at least one of the compounds
described above.
[0030] The insulating layer 21 may further contain an additive such
as a filler. Alternatively, the insulating layer 21 may contain
only the liquid crystal polymer.
[0031] Moreover, in the metal clad laminated plate 1 according to
the present embodiment, the number of voids which exist between the
metal foil 3 and the insulating layer 21 and appear in the cross
section as shown in FIG. 2 is preferably three or less per 10 .mu.m
in length in the direction orthogonal to a direction in which the
metal foil 3 and the insulating layer 21 face each other. In this
case, engagement of the insulating layer 21 and the metal foil 3 to
each other is improved, which can improve the adhesiveness (pull
strength) between the insulating layer 21 and the metal foil 3. The
number of voids appearing between the insulating layer 21 and the
metal foil 3 is preferably as small as possible and is particularly
preferably zero. Note that the voids are voids 23 at the border
between the insulating layer 21 and the metal foil 3 as shown in
FIG. 4.
[0032] The metal clad laminated plate 1 according to the present
embodiment is manufactured by, for example, a double belt press
method.
[0033] <Method for Manufacturing Metal Clad Laminated
Plate>
[0034] Next, a manufacturing method of the metal clad laminated
plate 1 according to the embodiment will be described with
reference to FIGS. 5 and 6.
[0035] The manufacturing method is a method for manufacturing the
metal clad laminated plate 1. Thus, the present embodiment may make
reference to the description of the metal clad laminated plate
1.
[0036] The manufacturing method includes a preparation step and a
molding step.
[0037] The preparation step is a step of preparing the insulating
film 2 and the metal foils 3. Each metal foil 3 has a surface
(hereinafter referred to as a contact surface) to be laid on the
insulating film 2, and the ten-point average roughness (Rzjis),
which is defined in JIS B 0601:2001, of the contact surface is
preferably greater than or equal to 0.5 .mu.m and less than or
equal to 3 .mu.m. Adopting the metal foil 3 whose contact surface
having such a ten-point average roughness (Rzjis) in manufacturing
of the metal clad laminated plate 1 provides ten-point average
roughness (Rzjis) calculated from the roughness curve c as
illustrated in FIG. 3. The roughness curve c is obtained from the
shape of the surface, which is in contact with the insulating layer
21 in the cross section of the metal clad laminated plate 1, of the
metal foil 3. Moreover, the ten-point average roughness (Rzjis) may
be greater than or equal to 1.0 .mu.m and less than or equal to 2.5
.mu.m.
[0038] The mean width of profile elements (RSm), which is defined
in JIS B 0601:2001, of the contact surface is preferably greater
than or equal to 10 .mu.m and less than or equal to 65 .mu.m, and
more preferably greater than or equal to 20 .mu.m and less than or
equal to 65 .mu.m. Adopting the metal foil 3 whose contact surface
having such a mean width of profile elements (RSm) in manufacturing
of the metal clad laminated plate 1 provides a mean width of
profile elements (RSm), the mean width being calculated from the
roughness curve c as illustrated in FIG. 3. The roughness curve c
is obtained from the shape of the surface, which is in contact with
the insulating layer 21 in the cross section of the metal clad
laminated plate 1, of the metal foil 3.
[0039] The roughness of the contact surface is adjusted by
subjecting the surface of the metal foil 3 to, for example, an
appropriate roughening process. Moreover, when the metal foil 3 is
an electrolytic copper foil, the electrolytic copper foil has a
matte surface formed when the electrolytic copper foil is
manufactured. The matte surface may be processed to have the
above-described roughness, and the matte surface thus processed may
be used as the contact surface.
[0040] The insulating film 2 contains a liquid crystal polymer.
Such an insulating film 2 preferably has a melting point of higher
than or equal to 300.degree. C. and lower than or equal to
345.degree. C. The melting point of the insulating film 2 can be
obtained by being measured by, for example, differential scanning
calorimetry (DSC). Moreover, the thickness of the insulating film 2
is arbitrarily selected and is, for example, greater than or equal
to 12.5 .mu.m and less than or equal to 200 .mu.m.
[0041] The insulating film 2 may further contain an additive such
as a filler. Alternatively, the insulating film 2 may contain only
the liquid crystal polymer. When the insulating film 2 contains an
additive, the melting point of the insulating film 2 is preferably
the same as the melting point of the liquid crystal polymer (the
insulating film containing only the liquid crystal polymer).
[0042] Moreover, in the preparation step, each of the insulating
film 2 and the metal foils 3 is once rolled up and is thus formed
in the form of a roll. Then, the insulating film 2 in the form of a
roll is installed in a delivery apparatus 5 which will be described
later, and the metal foils 3 each in the form of a roll are
installed in delivery apparatuses 6 which will be described
later.
[0043] In the present embodiment, the preparation step is
performed, and then, the molding step is performed.
[0044] The molding step is a step of forming a metal clad laminated
plate from a laminated body including the insulating film 2 and the
metal foils 3 laid on the insulating film 2 and is performed by a
metal clad laminated plate manufacturing device (hereinafter
referred to as a manufacturing device) as illustrated in FIG.
5.
[0045] The manufacturing device includes the delivery apparatus 5
configured to deliver the insulating film 2, the delivery
apparatuses 6 configured to deliver the metal foils 3, a winder 8
configured to roll up the metal clad laminated plate 1, and a
double belt press device 7 disposed between the winder 8 and a set
of the delivery apparatuses 5 and 6.
[0046] The double belt press device 7 includes a pair of endless
belts 4, drums 9, and a pair of thermal pressure devices 10. The
pair of endless belts 4 are vertically disposed with the laminated
body being sandwiched therebetween. Of the pair of endless belts 4,
one endless belt 4 encircles two drums 9, and the other endless
belt 4 encircles two drums 9. The pair of thermal pressure devices
10 are disposed with the endless belts 4, 4 and the laminated body
being sandwiched therebetween. The thermal pressure devices 10
hot-presses the laminated body via the endless belts 4. The thermal
pressure devices 10 includes, for example, a hydraulic plate. The
hydraulic plate is configured to hot-press the laminated body via
the endless belts 4 by the hydraulic pressure of, for example,
heated liquid.
[0047] The endless belt 4 is not specifically limited but is made
of, for example, metal.
[0048] Moreover, the pair of drums 9 vertically facing each other
rotate to deliver the laminated body toward the winder 8. Along
with this rotation, the pair of endless belts 4 turn.
[0049] In the molding step, the delivery apparatus 5 holds the
insulating film 2 in a rolled state and continuously feeds the
insulating film 2 to the double belt press device 7. The delivery
apparatuses 6 hold the metal foils 3 in a rolled state and
continuously feed the metal foils 3 to the double belt press device
7. Thus, between the double belt press device 7 and the set of the
delivery apparatuses 5 and 6, the laminated body including the
insulating film 2 and the metal foils 3 laid on the insulating film
2 is formed, and the laminated body is hot-pressed by the double
belt press method. The double belt press method is performed by the
double belt press device 7.
[0050] The double belt press method adopted in the molding step
applies uniform pressure to the entirety of a pressurizing surface
of the laminated body via the pair of endless belts 4. This reduces
variations in the pressure applied to the insulating film 2 and
reduces the interior stress in the insulating layer 21 of the metal
clad laminated plate 1 to be obtained after the molding step. Thus,
the dimensional stability of the metal clad laminated plate 1 is
improved and is easily stabilized.
[0051] When the laminated body is hot-pressed, for example, the
laminated body is heated as the laminated body comes close to the
double belt press device 7. Next, the laminated body is further
heated while the laminated body passes the drums 9, the laminated
body is hot-pressed via the endless belts 4 while the laminated
body passes between the thermal pressure devices 10, and the
laminated body is heated to the highest heating temperature. Then,
the laminated body, which has been hot-pressed, passes the drums 9
and is cooled as the laminated body is away from the thermal
pressure devices 10.
[0052] The highest heating temperature when the laminated body is
hot-pressed via the endless belts 4 by the thermal pressure devices
10 is preferably higher than or equal to a temperature which is
lower than the melting point of the insulating film 2 by 5.degree.
C. and lower than or equal to a temperature higher than the melting
point of the insulating film 2 by 20.degree. C. In this case, a
reduced number of voids is formed between the insulating layer 21
and the metal foil 3 of the metal clad laminated plate 1 to be
formed, so that high adhesive strength (pull strength) can be
obtained between the insulating layer 21 and the metal foil 3. In
addition, the metal clad laminated plate 1 can obtain a preferred
plate thickness accuracy. The plate thickness accuracy enables the
metal clad laminated plate 1 to easily obtain preferred
high-frequency transmission characteristics. Moreover, the highest
heating temperature is preferably maintained for longer than or
equal to 20 seconds and shorter than or equal to 120 seconds. In
this case, a reduced number of voids is formed between the
insulating layer 21 and the metal foil 3 of the metal clad
laminated plate 1 to be formed, so that high adhesiveness can be
obtained between the insulating layer 21 and the metal foil 3. In
addition, the metal clad laminated plate 1 can obtain a preferred
plate thickness accuracy. The plate thickness accuracy enables the
metal clad laminated plate 1 to easily obtain high-frequency
transmission characteristics.
[0053] The laminated body is hot-pressed preferably at a pressure
of greater than or equal to 2 MPa and less than or equal to 5 MPa.
In this case, a reduced number of voids is formed between the
insulating layer 21 and the metal foil 3 of the metal clad
laminated plate 1 to be formed, so that high adhesiveness can be
obtained between the insulating layer 21 and the metal foil 3.
Moreover, the pressure may be less than 4.0 MPa or may be less than
or equal to 3.5 MPa.
[0054] Furthermore, in the molding step, application of nonuniform
pressure to the insulating film 2 impairs the plate thickness
accuracy of the metal clad laminated plate 1 to be obtained, which
tends to impair the high-frequency transmission characteristics.
Thus, hot pressing by the double belt press device 7 enables
uniform pressure to be applied to the insulating film 2. This
enables the plate thickness accuracy of the metal clad laminated
plate 1 to be improved and enables the metal clad laminated plate 1
to obtain preferred high-frequency transmission
characteristics.
[0055] In the present embodiment, the metal clad laminated plate 1
continuously delivered from the double belt press device 7 is
rolled up in the form of a roll by the winder 8.
[0056] The metal clad laminated plate 1 thus manufactured is
applicable to manufacturing of the printed wiring board. For
example, the metal foil 3 of the metal clad laminated plate 1 may
be subjected to an arbitrary wiring process, thereby manufacturing
the printed wiring board. To the printed wiring board, an
insulating layer and a conductor wire may be added by an
appropriate method to obtain a multilayered printed wiring
board.
[0057] The material for the insulating layer may be the same
material as that for the insulating layer 21 or may be different
from that for the insulating layer 21.
[0058] The material for the metal layer may be the same as that for
the metal foil 3 or may be different from that of the metal foil
3.
[0059] <Variation>
[0060] In the embodiment described above, the metal clad laminated
plate 1 is a double-sided metal clad laminated plate.
Alternatively, the metal clad laminated plate 1 may be a
single-sided metal clad laminated plate. For manufacturing the
single-sided metal clad laminated plate, one delivery apparatus 6
of the two delivery apparatuses 6 feeds a stripping sheet laid on
the insulating film 2 to the double belt press device 7. The
stripping sheet has at least releasability from the insulating
layer 21 and may be any sheet material. The stripping sheet is made
of, for example, a resin material such as a polyimide resin or a
tetrafluoro ethylene resin which provides both the releasability
and the heat resistance.
EXAMPLE
[0061] The present disclosure will be specifically described with
reference to examples below.
Examples and Comparative Examples
[0062] Each of examples and comparative examples are embodied by
using the following materials.
[0063] <Metal Foil 3> [0064] Metal foil A: "TP4-S" (copper
foil) manufactured by Fukuda Metal Foil & Powder Co., Ltd.
[0065] Metal foil B: "F2WS" (copper foil) manufactured by Furukawa
Electric Co., Ltd. [0066] Metal foil C: "3EC-VLP" (copper foil)
manufactured by Mitsui Mining & Smelting Co., Ltd. [0067] Metal
foil D: "TQ-M7-VSP" (copper foil) manufactured by Mitsui Mining
& Smelting Co., Ltd. [0068] Metal foil E: "BHFX-P92C-HA-V2"
(copper foil) manufactured by JX Nippon Mining & Metals
Corporation
[0069] <Insulating Film 2> [0070] Insulating film A: "Vecstar
CT-Z" manufactured by Kuraray Co., Ltd. [0071] Insulating film B:
"Vecstar CT-Q" manufactured by Kuraray Co., Ltd.
First Example
[0072] An insulating film A was sandwiched between rough surfaces
of two metal foils A with a metal clad laminated plate
manufacturing device having the structure shown in FIG. 5, thereby
producing a laminated body, and then, the laminated body was
hot-pressed by a double belt press method, thereby manufacturing a
metal clad laminated plate. The laminated body was hot-pressed at a
pressure of 3.5 MPa, where the highest heating temperature was
335.degree. C. and the highest heating temperature was maintained
for 30 seconds.
Second Example
[0073] A metal clad laminated plate 1 was manufactured by a similar
method to the first example except that metal foils B were used in
place of the metal foils A.
Third Example
[0074] A metal clad laminated plate 1 was manufactured by a similar
method to the first example except that an insulating film B was
used in place of the insulating film A and the laminated body was
hot-pressed under a pressure of 3.5 MPa with the highest heating
temperature of 310.degree. C. being maintained for 50 seconds.
Fourth Example
[0075] An insulating film B was sandwiched between rough surfaces
of two metal foils C, thereby providing a laminated body. Then, the
laminated body was hot-pressed by the double belt press method
under the condition shown in Table 1, thereby manufacturing a
double-sided metal clad laminated plate (a metal clad laminated
plate 1).
Fifth Example
[0076] An insulating film B was sandwiched between rough surfaces
of two metal foil D, thereby providing a laminated body. Then, the
laminated body was hot-pressed by the double belt press method
under the condition shown in Table 1, thereby manufacturing a
double-sided metal clad laminated plate (a metal clad laminated
plate 1).
Sixth Example
[0077] An insulating film B was sandwiched between rough surfaces
of two metal foils E, thereby providing a laminated body. Then, the
laminated body was hot-pressed by the double belt press method
under the condition shown in Table 1, thereby manufacturing a
double-sided metal clad laminated plate (a metal clad laminated
plate 1).
First Comparative Example
[0078] An insulating film A was sandwiched between rough surfaces
of two metal foil A, thereby providing a laminated body. Then, the
laminated body was hot-pressed between two molding boards under the
condition shown in Table 1 below, thereby manufacturing a
double-sided metal clad laminated plate (a metal clad laminated
plate 1).
Second Comparative Example
[0079] An insulating film B was sandwiched between rough surfaces
of two metal foil B, thereby providing a laminated body. Then, the
laminated body was hot-pressed between two molding boards under the
condition shown in Table 1 below, thereby manufacturing a
double-sided metal clad laminated plate (a metal clad laminated
plate 1).
Third Comparative Example
[0080] An insulating film A was sandwiched between rough surfaces
of two metal foil A, thereby providing a laminated body. Then, the
laminated body was hot-pressed between two rolls under the
condition shown in Table 1 below, thereby manufacturing a
double-sided metal clad laminated plate (a metal clad laminated
plate 1).
Fourth Comparative Example
[0081] An insulating film B was sandwiched between rough surfaces
of two metal foil B, thereby providing a laminated body. Then, the
laminated body was hot-pressed between two rolls under the
condition shown in Table 1 below, thereby manufacturing a
double-sided metal clad laminated plate (a metal clad laminated
plate 1).
Fifth Comparative Example
[0082] An insulating film A was sandwiched between rough surfaces
of two metal foils B, thereby providing a laminated body. Then, the
laminated body was hot-pressed by the double belt press method
under the condition shown in Table 1 below, thereby manufacturing a
double-sided metal clad laminated plate (a metal clad laminated
plate 1).
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4
Example 5 Example 6 LCP Material Type Insulating Insulating
Insulating Insulating Insulating Insulating Film A Film A Film B
Film B Film B Film B Thickness (.mu.m) 100 100 100 100 100 100
Melting Point (.degree. C.) 335 335 310 310 310 310 Copper Material
Type Metal Foil A Metal Foil B Metal Foil A Metal Foil C Metal Foil
D Metal Foil E Foil Thickness (.mu.m) 12 12 12 12 12 12 Rough
Ten-Point Average Roughness (Rzjis) 1.2 2.5 1.2 3.5 1.2 1.0 Surface
(.mu.m)*1 Mean Width of Profile Elements (RSm) 20 65 20 21 33 45
(.mu.m) *2 Molding Method Double Belt Double Belt Double Belt
Double Belt Double Belt Double Belt Press Press Press Press Press
Press Healing Temperature in Hot Press (.degree. C.) 335 335 310
310 310 310 Pressure in Hot Press (MPa) 3.5 3.5 3.5 3.5 3.5 3.5
Time for Hot Press (Second) 30 30 50 50 50 50 Metal Clad Cross- The
Average Number of Voids *3 0 0 0 0 0 0 Laminated Section Ten-Point
Average Roughness (Rzjis) 1.2 2.5 1.2 3.5 1.2 1.0 Plate (.mu.m)*4
Mean Width of Profile Elements 20 65 20 21 33 45 (RSm) (.mu.m) *5
Evaluation Pull Strength of Metal Foil from Insulating Layer 0.8 1
0.8 1.3 1.2 0.8 Result Plate Thickness Accuracy <.+-.10%
<.+-.10% <.+-.10% <.+-.10% <.+-.10% <.+-.10% Average
Thickness of Metal Clad 124 124 124 124 124 124 Laminated Plate
(.mu.m) Dimemsional Stability <.+-.0.1% <.+-.0.1%
<.+-.0.1% <.+-.0.1% <.+-.0.1% <.+-.0.1% High-Frequency
Transmission Charactristics -3.4 -5.5 -3.4 -6.1 -3.6 -3.4 (dB/100
mm) Comparative Comparative Comparative Comparative Comparative
Example 1 Example 2 Example 3 Example 4 Example 5 LCP Material Type
Insulating Insulating Insulating Insulating Insulating Film A Film
B Film A Film B Film A Thickness (.mu.m) 100 100 100 100 100
Melting Point (.degree. C.) 335 310 335 310 335 Copper Material
Type Metal Foil A Metal Foil B Metal Foil A Metal Foil B Metal Foil
B Foil Thickness (.mu.m) 12 12 12 12 12 Rough Ten-Point Average
Roughness (Rzjis) 1.2 2.5 1.2 2.5 2.5 Surface (.mu.m)*1 Mean Width
of Profile Elements (RSm) 20 65 20 65 65 (.mu.m) *2 Molding Method
Hot Plate Hot Plate Roll Press Roll Press Double Belt Press Press
Press Healing Temperature in Hot Press (.degree. C.) 330 305 340
315 335 Pressure in Hot Press (MPa) 3.5 3.5 4 4 4 Time for Hot
Press (Second) 5400 5400 10 10 10 Metal Clad Cross- The Average
Number of Voids .sup.*3 0 0 5 11 5 Laminated Section Ten-Point
Average Roughness (Rzjis) 1.2 2.5 1.2 2.5 2.5 Plate (.mu.m)*4 Mean
Width of Profile Elements 20 65 20 65 65 (RSm) (.mu.m) *5
Evaluation Pull Strength of Metal Foil from Insulating Layer 0.8 1
0.5 0.7 0.5 Result Plate Thickness Accuracy .+-.20% .+-.20% .+-.10%
.+-.10% .+-.10% Average Thickness of Metal Clad 120 120 124 124 124
Laminated Plate (.mu.m) Dimemsional Stability <.+-.0.2%
<.+-.0.2% <.+-.0.2% <.+-.0.2% <.+-.0.1% High-Frequency
Transmission Charactristics -3.4 -5.5 -3.4 -5.5 -5.5 (dB/100 mm)
*1-*2: Value per 10 .mu.m of travel distance of contact-type
surface roughness meter to rough surface of metal foil. *3-*5:
Value par 10 .mu.m in length in direction orthogonal to direction
in which metal foil and insulating layer face each other in
cross-section of metal clad laminated plate.
[0083] <Evaluation>
[0084] [Pull Strength]
[0085] From the metal clad laminated plate 1 of each of the
examples and the comparative examples, a test piece
(width.times.length=10 mm.times.150 mm) was produced. Based on the
test piece, the pull strength of the metal foil 3 from the
insulating layer 21 was measured in accordance with JIS C 6481.
[0086] [Plate Thickness Accuracy]
[0087] The plate thickness accuracy of the metal clad laminated
plate 1 of each of the examples and the comparative examples was
calculated by the following procedure. First, thicknesses of the
metal clad laminated plate 1 were measured at arbitrary ten pints
of the metal clad laminated plate 1. Then, an average value of the
thicknesses at the ten points was calculated, thereby obtaining the
average thickness of the metal clad laminated plate 1. In addition,
a maximum value and a minimum value of the thicknesses at the ten
points were respectively defined as a maximum thickness and a
minimum thickness. Next, the difference (d1) between the maximum
thickness and the average thickness and the difference (d2) between
the minimum thickness and the average thickness were calculated.
Then, a value as the ratio of the difference (d1) to the average
thickness and a value as the ratio of the difference (d2) to the
average thickness were calculated, thereby obtaining the plate
thickness accuracy of the metal clad laminated plate 1.
[0088] [Dimension Change (Dimensional Stability)]
[0089] The dimensional stability of the metal clad laminated plate
1 of each of the examples and the comparative examples was
calculated in accordance with IPC-TM650 No.2.2.4 Method C.
[0090] [Photograph of Cross Section]
[0091] The cross section of the metal clad laminated plate 1 of the
second example was photographed with a scanning electron
microscope, thereby obtaining the photograph shown in FIG. 2. In
addition, the cross section of the metal clad laminated plate 1 of
the second comparative example was photographed with the scanning
electron microscope, thereby obtaining the photograph shown in FIG.
4. The cross section shown in each of FIGS. 2 and 4 has a length b
of 10 .mu.m in a direction orthogonal to a direction in which the
metal foil 3 and the insulating layer 21 face each other. In the
photograph shown in FIG. 2, no void was observed between the
insulating layer 21 and the metal foil 3. In the photograph shown
in FIG. 4, ten voids 23 were observed between the insulating layer
21 and the metal foil 3. In this way, the number of voids formed at
the ten points in the cross section of the metal clad laminated
plate 1 of each of the examples and the comparative examples was
counted. Then, the total number of voids in each of the examples
and the comparative examples was divided by the number of cross
sections (ten points), thereby obtaining the average number of
voids formed in each metal clad laminated plate 1.
[0092] [High-Frequency Transmission Characteristics]
[0093] First, plating layers each having a thickness of 10 .mu.m
were further formed on both surfaces of the metal clad laminated
plate 1 of each of the examples and the comparative examples,
thereby forming metal layers each including the metal foil 3 and
the plating layer on respective surfaces of the metal clad
laminated plate 1. Next, one metal layer of the metal layers was
subjected to an etching process, thereby forming a signal circuit
(a microstrip line), and the other metal layer was defined as a
ground circuit. Thus, a test piece including the signal circuit and
the ground circuit was prepared. Then, the signal circuit was
caused to transmit a high-frequency electric signal, and the
transmission loss of the electric signal in the signal circuit was
measured at 25.degree. C. and at 40% RH by a probe method with
E5071C manufactured by Agilent Technologies Japan, Ltd. Next, the
transmission loss per 100 mm of the wire length of the signal
circuit was calculated as high-frequency transmission
characteristics. Table 1 shows the high-frequency transmission
characteristics in the case where the frequency of the electric
signal input to the signal circuit is 20 GHz.
[0094] <Measurement>
[0095] [Metal Foil]
[0096] [Ten-Point Average Roughness (Rzjis) of Rough Surface]
[0097] The ten-point average roughness (Rzjis), defined in JIS B
0601:2001, of the contact surface of the metal foil 3 was measured
before the metal clad laminated plate 1 was manufactured.
[0098] [Mean Width of Profile Elements (RSm)]
[0099] The mean width of profile elements (RSm), defined in JIS B
0601:2001, of the contact surface of the metal foil 3 was measured
before the metal clad laminated plate 1 was manufactured.
[0100] [Metal Clad Laminated Plate]
[0101] [Ten-Point Average Roughness (Rzjis) Calculated from
Roughness Curve Obtained from Cross Section of Metal Clad Laminated
Plate]
[0102] From the photograph of the cross section of each of the
examples and the comparative examples, the roughness curve c as
illustrated in FIG. 3 was created. Then, in accordance with JIS B
0601:2001, the ten-point average roughness (Rzjis) was calculated
based on the roughness curve c of each of the examples and the
comparative examples.
[0103] [Mean Width of Profile Elements (RSm)]
[0104] In accordance with JIS B 0601:2001, the mean width of
profile elements (RSm) was calculated based on the roughness curve
of each of the examples and the comparative examples.
REFERENCE SIGNS LIST
[0105] 1 METAL CLAD LAMINATED PLATE [0106] 21 INSULATING LAYER
[0107] 3 METAL FOIL
* * * * *