U.S. patent application number 08/022199 was filed with the patent office on 2001-12-06 for cylindrical coil and production process thereof.
Invention is credited to OHMI, HIROSHI, SHIMIZU, HIROSHI.
Application Number | 20010048979 08/022199 |
Document ID | / |
Family ID | 12504073 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010048979 |
Kind Code |
A1 |
OHMI, HIROSHI ; et
al. |
December 6, 2001 |
CYLINDRICAL COIL AND PRODUCTION PROCESS THEREOF
Abstract
The present invention enables selective plating of a substrate
by use of the method of removing or deactivating by an argon laser
beam L an electroless plating reaction catalyst imparted to the
substrate.
Inventors: |
OHMI, HIROSHI; (ANJO-SHI,
JP) ; SHIMIZU, HIROSHI; (NAGOYA-SHI, JP) |
Correspondence
Address: |
CUSHMAN, DARBY & CUSHMAN
1100 NEW YORK AVENUE, N.W.
NINTH FLOOR
WASHINGTON
DC
200053918
|
Family ID: |
12504073 |
Appl. No.: |
08/022199 |
Filed: |
February 25, 1993 |
Current U.S.
Class: |
427/555 ;
427/256 |
Current CPC
Class: |
H05K 3/185 20130101;
C23C 18/38 20130101; C23C 18/1612 20130101; C23C 18/204 20130101;
C23C 18/30 20130101; C23C 18/1608 20130101 |
Class at
Publication: |
427/555 ;
427/256 |
International
Class: |
B05D 003/06 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 25, 1992 |
JP |
4-37670 |
Claims
1. A plating method comprising the steps of: (1) imparting an
electroless plating reaction catalyst to a surface of a substrate;
(2) deactivating or removing the electroless plating reaction
catalyst imparted to the surface of the substrate by a
reaction-catalyst selective-imparting means at only desired
locations of the electroless plating reaction catalyst; and (3)
applying electroless plating to the locations of the substrate
having the electroless plating reaction catalyst.
2. A plating method as claimed in claim 1, wherein groove portions
are formed by the step (2) at locations of the substrate surface
irradiated by an energy beam.
3. A plating method as claimed in claim 1, wherein the catalyst
selective-imparting means works using a laser.
4. A cylindrical coil comprising: a cylindrical substrate and a
spiral-shaped conductor formed on at least one side surface of the
substrate, obtained by imparting an electroless plating reaction
catalyst on the side surface of the cylindrical substrate, then
deactivating or removing the electroless plating reaction catalyst
in the form of a continuous winding at the side surface of the
cylindrical substrate, then causing a reaction between the
electroless plating reaction catalyst and an electroless plating
solution.
5. A cylindrical coil as claimed in claim 4, wherein the heat
conductivity of the substrate is 4.5 to 8.4 w/m.multidot..degree.C.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method for selectively
imparting an electroless plating catalyst on a substrate to be
plated and to a cylindrical coil obtained using this method.
[0003] 2. Description of the Related Art
[0004] In the past, it has been known to forming, for example,
wiring on a printed circuit board by electroless plating employing
means using a resist, as typically represented by an additive
method.
[0005] The method of forming a pattern on a printed circuit board
by the additive method called for an electroless plating reaction
catalyst, for example, palladium (Pd), to be imparted to the
surface of the insulating substrate, then the portions other than
the conductor circuit of the substrate to be covered by a resist
and the substrate covered with the resist to be immersed in an
electroless plating solution, whereby electroless plating was
applied on only the uncovered portions on the substrate. This
additive method, however, had the problem of an extremely large
number of steps and the need for complicated work, as mentioned
above.
[0006] Therefore, in the past, to overcome this problem, for
example, as disclosed in Japanese Unexamined Patent Publication
(Kokai) No. 63-212285 or Japanese Unexamined Patent Publication
(Kokai) No. 62-218580, there had been proposed the method of
directly drawing the wiring on a ceramic substrate, without the use
of a resist, by using the local heating effect of a laser.
Explaining this method of using the local heating effect of a laser
in more detail, when for example using an alumina nitride
substrate, the irradiation of the laser causes a reaction of:
AlN.fwdarw.Al.sup.0+1/2N.sub.2
[0007] and changes the substrate to the metal (here, aluminum metal
as shown by Al.sup.0) at the laser-irradiated portions of the
substrate. The aluminum metal obtained by this laser irradiation
is, in turn, used as the nucleus for electroless plating, thereby
forming a circuit.
[0008] In the above method, however, in the case of an alumina
nitride substrate, for example, the substrate has to be placed in a
vacuum atmosphere so as to prevent the formation of an oxide layer
such as alumina (Al.sub.2O.sub.3) on the surface of the substrate,
necessitating expensive, large-sized facilities such as vacuum
chambers. Further, even substrates such as AlN which are relatively
easily metallized by irradiation by a laser require use of a high
output pulse laser (hereinafter referred to as a YAG) of a peak
output of 4 kW, a pulse width of 200 ns, and a repetition of 1 kHz.
In the past, since use was made of a pulse laser, it was extremely
difficult to form wiring with uniform wire widths, to increase the
drawing speed, etc.
[0009] Further, regarding prior art coils, for example, as shown
in, for example, U.S. Pat. No. 4,903,674, there have been proposed
coils etc. attached to spark plugs of internal combustion engines.
These have been manufactured by the additive method or the etching
method, both of which use the above-mentioned circuit forming
method, i.e., the resist method, which are complicated in steps and
require difficult technology for attachment of a resist on a curved
surface. Therefore, as shown in Japanese Unexamined Patent
Publication (Kokai) No. 63-212285 and Japanese Unexamined Patent
Publication (Kokai) No 62-218580, consideration has been given to
applying electroless plating to just the laser-irradiated portions,
but as mentioned above, the formation of wiring with uniform wire
widths, the increase of the drawing speed, etc. end up becoming
extremely difficult.
SUMMARY OF THE INVENTION
[0010] Accordingly, the objects of the present invention are to
elminate the above-mentioned disadvantages of the prior art and to
provide a plating method capable of selectively imparting an
electroless plating catalyst selectively to a circuit substrate
etc. simply and with few steps.
[0011] Another object of the present invention is to provide a
cylindrical coil obtained by selective formation of a coil wiring
pattern by plating, without the use of the resist method
accompanying with its complicated steps.
[0012] In accordance with the present invention, there is provided
a plating method comprising:
[0013] (1) imparting an electroless plating reaction catalyst to a
surface of a substrate;
[0014] (2) deactivating or removing the electroless plating
reaction catalyst imparted to the substrate surface by a
reaction-catalyst selective-imparting means at only desired
locations of the electroless plating reaction catalyst; and
[0015] (3) applying electroless plating to the locations of the
substrate having the electroless plating reaction catalyst.
[0016] In accordance with the present invention, there is also
provided a cylindrical coil having a cylindrical substrate and a
spiral-shaped conductor formed on at least one side surface of the
substrate, obtained by imparting an electroless plating reaction
catalyst on the side surface of the cylindrical substrate, then
deactivating or removing the electroless plating reaction catalyst
in the form of a continuous winding at the side surface of the
cylindrical substrate, then causing a reaction between said
electroless plating reaction catalyst and an electroless plating
solution.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The present invention will be better understood from the
description set forth below with reference to the accompanying
drawings, wherein:
[0018] FIG. 1 is an explanatory view showing the plating method of
the present invention;
[0019] FIG. 2 is an explanatory view showing the plating method of
the present invention;
[0020] FIG. 3 is an explanatory view showing the plating method of
the present invention;
[0021] FIG. 4 is an explanatory view showing the plating method of
the present invention;
[0022] FIG. 5 is an explanatory view showing the plating method of
the present invention;
[0023] FIG. 6 is an explanatory view showing the plating method of
the present invention;
[0024] FIG. 7 is a sectional view of the plating shape obtained by
the plating method of the present invention;
[0025] FIG. 8 is a graph of the relationship of the nonplated width
to the laser energy;
[0026] FIG. 9(a) to (d) are explanatory views showing the plating
method of a second embodiment of the present invention;
[0027] FIG. 10 is a perspective view of an apparatus used in a
third embodiment of the present invention;
[0028] FIG. 11 is an explanatory view showing the second step of
the plating method of the third embodiment of the present
invention;
[0029] FIG. 12 is an explanatory view showing the second step of
the plating method of the third embodiment of the present
invention;
[0030] FIG. 13 is a schematic view showing the cylindrical coil
obtained by the third embodiment of the present invention; and
[0031] FIG. 14 is a graph showing the relationship of the nonplated
width of the metal Pd catalyst with the laser scanning speed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] In the first aspect of the present invention, the method is
employed of imparting to a surface of a substrate an electroless
plating reaction catalyst, deactivating or removing the electroless
plating reaction catalyst imparted to the substrate surface by a
reaction-catalyst selective-imparting means at only desired
locations of the electroless plating reaction catalyst, and
applying electroless plating to the locations to which the
electroless plating reaction catalyst has been selectively applied,
so use is made of the means of deactivating or removing the
catalyst and therefore treatment in the atmosphere becomes
possible. Further, it is sufficient merely to deactivate or remove
the electroless plating reaction catalyst, so electroless plating
can be applied at a low energy to predetermined portions and thus
formation of wiring with uniform wiring width, an increase of the
drawing speed, and the like become possible.
[0033] Further, in the second aspect of the invention, it is
possible to form electroless plating enabling formation of wiring
with uniform wire widths, increased drawing speeds, etc. even using
a cylindrical insulating material as a substrate and with a curved
side surface, so it becomes possible to obtain a winding-less
cylindrical coil and it becomes possible to cut a large number of
parts, lighten the weight, and reduce the size compared with
conventional winding type coils.
[0034] According to the present invention, it is sufficient to
deactivate or remove the electroless plating reaction catalyst, so
it is possible to place the substrate in the atmosphere, so not
only is it possible to reduce the cost of the facilities, but also
the degree of freedom of selectively imparting the catalyst to the
substrate becomes greater and easy application even to a
three-dimensional circuit becomes possible. Further, the
deactivation or removal of the electroless plating reaction
catalyst does not require causing a reduction reaction of the
substrate itself as in the past, so there is no need to use a high
output pulse laser, it is possible to perform the operation with a
much lower energy compared with the past, and further the speed of
movement can be made faster, so miniaturization of the wiring can
be realized.
EMBODIMENTS
[0035] FIGS. 1 to 6 show the plating method of the present
invention.
[0036] Reference numeral 1 is the substrate used in the first
embodiment. It is a flat substrate comprised of 60% alumina and the
balance of silica, magnesia, kaolin, etc. The substrate 1 was
degreased, then immersed for 10 minutes in a 33% by weight NaOH
solution of a bath temperature of 80.degree. C. so as to improve
the adhesive power of the plating. Next, to impart the catalyst,
i.e., perform the first step, the degreased substrate 1 was
immersed for about 10 minutes in Activator Neogant 834 (catalyst Pd
ion imparting agent made by Nihon Schering K.K.) of 40.degree. C.
so as to make bivalent Pd ions deposit on the substrate, then it
was immersed for about 5 minutes in Reducer Neogant WA (catalyst Pd
imparting agent made by Nihon Schering K.K.) of 40.degree. C. to
reduce the bivalent Pd to a metal and form a metal palladium layer
(hereinafter referred to as metal Pd) on the surface of the
substrate 1 as a whole, as shown in FIG. 2.
[0037] Next, as a second step, as shown in FIG. 3, an argon laser
beam L was irradiated in the atmosphere on the substrate 1 covered
on its surface with metal Pd 2 from a not shown argon laser
apparatus (Model 2020 made by Spectra Physics Co.) via condensing
lenses 3 and 4 etc. condensed to a diameter of about 10 .mu.m. At
the same time, the substrate 1 was made to move at a constant speed
by a not shown XY-stage carrying the substrate so as to deactivate
or remove the catalyst at the portions where electroless plating
was not to be applied. Next, the substrate 1 was immersed in an
electroless copper plating bath (OPC Copper T made by Okano Seiyaku
Kogyo), whereupon, as shown in FIG. 4, nonplated portions 6 were
formed at just the locations corresponding to the laser-irradiated
portions and whereupon the wiring portions 8a and the outer
circumference portions 8b of the electroless plated portions 8
could be created to the portions not irradiated with the laser.
[0038] FIG. 7 shows the cross-section along A-A of FIG. 4. Between
the wiring portions 8a and the outer circumference portions 8b are
formed the nonplated portions 6, which nonplated portions 6 are
comprised of the groove portions 6a removed by the argon laser beam
L and the oxide portions 6b oxidized by the heat of the argon laser
beam L. The width of the groove portions 6a is about 10 .mu.m. The
depth is 20 .mu.m. The catalyst 2 is completely removed in the
groove portions 6a, so no electroless plating film is formed at all
there. The width of the oxide portions 6b is about 20 .mu.m at both
sides of the groove portions 6a. The width depends, however, on the
intensity of the argon laser beam L. At this oxide portions 6b, the
catalyst 2 was deactivated by the heat and no electroless plating
was formed at these portions either. In other words, the catalyst
could be removed and deactivated as mentioned above by irradiation
by the argon laser beam L, so it was possible to eliminate the
formation of the electroless plating film at just the desired
portions.
[0039] Further, in the present embodiment, by causing the groove
portions 6a to be formed between the wiring portions 8a and the
outer circumference portions 8b, the distance between the wiring
portions Sa and the outer circumference portions 8b is made greater
than the mere straight line distance, whereby the distance along
the surface between the wiring portions 8a is lengthened and the
withstand voltage becomes greater.
[0040] When reducing the resistance of the wiring formed, one may
increase the thickness by further electroless plating alone at the
catalyst-imparted substrate 1 irradiated by the laser beam at the
outer circumference portions of the wiring portions 8a shown in
FIG. 4 or else may apply electroless plating to 2 to 3 .mu.m as a
base layer, then immerse a catalyst imparted substrate 1 having the
electroless plated portions 8 and the anode electrode 10 in an
electrolytic solution comprised of a copper sulfate plating bath,
for example, as shown in FIG. 5, then apply the cathode to the
catalyst-imparted substrate 1 by the cathode electrode 12 so as to
create the desired film thickness.
[0041] When applying such electroplating, in particular when using
a copper sulfate plating bath, by plating to increase the thickness
of the wiring portions 8a and at the same time etching (removing)
the copper of the outer circumference portions 8b other than the
wiring portions 8a, it becomes possible to obtain the substrate 1
having only the wiring portions 8a as shown in FIG. 6.
[0042] FIG. 8 shows the relationship with the nonplated width when
changing the irradiated laser output and changing the speed of
movement of the substrate.
[0043] Here, the "nonplated width" refers to the width of the
nonplated portion 6 shown by 1 in FIG. 7.
[0044] The type of substrate and the laser used are the same as the
ones used in the previous embodiment. The only difference from the
previous embodiment is that the output and the speed of movement
are changed.
[0045] As clear from FIG. 8, the nonplated width is determined by
the laser output and the speed of the member (relative speed of
beam and member) when the condensed diameter is constant. That is,
the lower the laser output, the smaller the nonplated width may be
made and therefore the more formation of fine wiring becomes
possible. When the laser output is too low or the rotational speed
(relative speed) is too fast, however, the catalytic action of the
Pd is not lost, it is learned.
[0046] Further, as mentioned above, under conditions where the
irradiated portion becomes nonplated, processing grooves are formed
in the substrates by the laser and the distance along the surface
between the wirings becomes longer, which is advantageous in terms
of the insulation between wirings.
[0047] In the above embodiment, after careful study, it was found
that a substrate having a pattern with a wiring width/wiring space
of 50/50 .mu.m (copper plated layer of 10 .mu.m) can be obtained
under conditions of a laser output of 5 W and a speed of movement
of 50 mm/sec.
[0048] Further, to obtain the desired wiring width in substrates of
various materials, it is sufficient to experiment in the same way
as with FIG. 8 in advance for each substrate and obtain a grasp of
the nonplated width.
[0049] Next, a detailed explanation will be given, as a second
embodiment, of a process of production of a cylindrical coil of the
second aspect of the invention using the above plating method.
[0050] FIG. 9(a) shows a cylindrical member 20 comprised of 60%
alumina ceramic formed to an outer diameter of 13 mm, an inner
diameter of 9 mm, and a length of 70 mm.
[0051] This cylindrical member 20 was degreased, then etched by
immersion in 33% NaOH, then the electroless plating reaction
catalyst, metal Pd, was imparted to the cylindrical member 20 as a
whole by Activator Neogant 834 and Reducer Neogant WA made by Nihon
Schering K.K. FIG. 9(b) shows the cylindrical member 20 on whose
outer surface the metal Pd layer 21 was formed.
[0052] Next, as shown in FIG. 9(c), an argon laser beam L of an
output of 6 W was condensed to a diameter of about 10 .mu.m by a
lens 22 and irradiated in a spiral-manner. The rotational speed of
the cylindrical member 20 was made 1.0 sec/rev and the speed of
movement was made 100 .mu.m/sec. By the irradiation of the argon
laser beam, it was possible to remove or deactivate the metal Pd
layer at the irradiated portions.
[0053] After the irradiation of the laser beam, the cylindrical
member 20 was immersed for 30 seconds in an electroless copper
plating bath (OPC Copper T made by Okano Seiyaku Kogyo), whereupon
it was possible to obtain a winding-free fine cylindrical coil with
a wiring width/wiring space of 40/60 .mu.m (plating thickness of 2
.mu.m) as shown in FIG. 9(d).
[0054] Here, the pitch of the coil wiring may be adjusted as
desired by the rotational speed of the cylindrical member and the
speed of equilibrium movement.
[0055] Further, the wiring width is determined by the set wiring
pitch and the nonplated width of the Pd catalyst caused by the
laser beam.
[0056] Next, a detailed explanation will be made of a cylindrical
coil with a coil formed not only at the outer surface of the
cylindrical member, but also at the inner surface, which had been
impossible in prior art windings, as a third embodiment, and to a
process for production of the same.
[0057] FIG. 10 is view of the apparatus used for the third
embodiment.
[0058] In FIG. 10, 25 is an argon gas laser generator--a Model
12020 argon gas laser unit made by Spectra Physics Co. The argon
laser beam L issued from this laser generator 25 passes via the
reflecting lens 26 and the condensing unit 27 so that the laser
beam is irradiated only in a predetermined direction from the laser
irradiation portion 28 provided at the tip of the condensing unit
27.
[0059] The cylindrical member 30 is comprised of 60% alumina and is
100 mm in length, 16 mm in outer diameter, and 13 mm in inner
diameter (thickness of 1.5 mm). The cylindrical member 30 was
degreased, teen etched by immersion in 33% NaOH, then a metal Pd
layer 31 was imparted to the inner surface 30a and outer surface
30b of the cylindrical member 30 as a whole by Activator Neogant
834 and Reducer Neogant WA made by Nihon Schering K.K.
[0060] The cylindrical member 30 with the metal Pd layer 31 is
fixed in place by a work clamp 32. The work clamp 32 is arranged on
an X-stage 33 which can be moved in the left and right directions.
It is rotatable along with the cylindrical member 30 by a motor
34.
[0061] The apparatus shown in FIG. 10 is employed to fabricate a
primary coil (low voltage side) at the outer surface 30a of the
cylindrical member 30 and a secondary coil (high voltage side) at
the inner surface 30b.
[0062] The method of irradiation of the laser beam on the inner
surface 30a and the outer surface 30b of the cylindrical member 30
using the apparatus of FIG. 10 will be explained below using FIG.
11 and FIG. 12.
[0063] FIG. 11 and FIG. 12 are sectional views of the
above-mentioned condensing unit 27 and schematic views showing the
method of irradiation of an argon laser beam to the inner
circumferential surface 30a and the outer circumferential surface
30b of the cylindrical member 30. When irradiating an argon laser
beam L to the inner surface 30a of the cylindrical member 30, as
shown in FIG. 11, first the laser irradiation portion 28 of the
condensing unit 27 is disposed at the inner surface 30a of the
cylindrical member 30. Next, the argon laser beam is issued from
the laser generator 25, whereupon the argon laser beam L passes via
the reflecting plate 26 to the condensing unit 27. The argon laser
L incident here travels in the condensing unit 27 via a beam
expander 40, reflecting mirror 41, condensing lens 42, and
reflecting mirror 43 and is irradiated from the laser irradiation
portion 28 to the inner surface 30a of the cylindrical member 30.
While the argon laser beam L is being irradiated from the
irradiation portion 28, the cylindrical member 30 is being rotated
by the motor 34 and the cylindrical member 30 is being moved by the
X-stage 33. Due to the rotation and movement of the cylindrical
member 30 the argon laser beam L is irradiated in a spiral fashion
on the inner surface 30a. After the argon laser L is irradiated
enough for a predetermined number of turns, the X-stage 33 is moved
so as to take the laser irradiation portion 28 out from the inside
of the cylindrical member 30.
[0064] Next, the outer surface 30b of the cylindrical member 30 is
irradiated by the argon laser beam L. The irradiation of the outer
surface 30b is performed, as shown in FIG. 12, by arranging the
laser irradiation portion 28 of the condensing unit 27 at a
predetermined location of the cylindrical member 30 by moving the
X-stage 33 and the condensing unit 27. After this, in the same way
as with the case of irradiating a laser beam on the inner surface
30a, a laser beam is irradiated from the laser irradiation portion
28. By rotating and moving the cylindrical member 30, the laser
beam is made to irradiate in a spiral fashion on the outer surface
30b of the cylindrical member 30.
[0065] Table 1 shows the conditions, such as the rotational speed
of the cylindrical member 30, at the time of laser irradiation.
1 TABLE 1 Outer Inner surface surface side side Rotational speed of
10 sec/rev 1 sec/rev member Speed of movement in 1000 .mu.m/sec 100
.mu.m/sec lateral direction Wiring space 10,000 .mu.m 100 .mu.m
Laser output 5W 5W
[0066] By doing the above, it is possible to irradiate a laser beam
in a spiral fashion at both the inner surface 30a and the outer
surface 30b of the cylindrical member 30.
[0067] The cylindrical member 30 irradiated with the laser beam in
a spiral manner was immersed in a not shown OPC Copper T
electroless copper plating bath made by Okano Seiyaku Kogyo and
plated to a thickness of 25 .mu.m, thereby obtaining a cylindrical
member 30 with conductive electroless plating formed in a spiral
fashion on the inner and outer surfaces.
[0068] The structure of this cylindrical member 30 is shown in
Table 2.
2 TABLE 2 Outer Inner surface surface side side No. of turns 10
1000 Wiring width/Wiring 9800 .mu.m/200 .mu.m 50 .mu.m/50 .mu.m
space Wiring sectional area 0.245 mm.sup.2 0.00125 mm.sup.2
[0069] FIG. 13 shows the outer appearance of the cylindrical member
after coil formation.
[0070] The sectional areas of the wirings of the outer surface side
50a and the inner surface side 50b of the winding-less cylindrical
coil 50 obtained by the third embodiment shown in FIG. 13 are, as
shown in Table 2, 0.245 mm.sup.2 and 0.00125 mm.sup.2,
respectively, which corresponds to a diameter of a winding in a
conventional winding coil of 560 .mu.m.phi. in the case of the
outer surface side 50a and 40 .mu.m.phi. in the case of the inner
surface side 50b.
[0071] If a not shown magnetic core is inserted into the magnetic
hole 51 of the cylindrical coil 50 and a primary voltage is applied
to the two ends 51 and 52 of the wiring formed on the outer surface
side 50a, it is possible to generate a secondary voltage between
the two ends 53 and 54 of the wiring formed at the inner surface
side 50b.
[0072] In the third embodiment, the secondary voltage was made 100
times the primary voltage in design, but when a greater secondary
voltage is required, use may be made of a longer cylindrical member
or use may be made of cylindrical members with different diameters
places one inside the other to make multiple layers.
[0073] Finally, we considered that there might be substrate
conditions excellent for the plating method of the present
invention and therefore engaged in careful studies on the selection
of the substrate.
[0074] That is, the present invention is characterized in that the
second step of selectively removing or deactivating the electroless
plating reaction catalyst is applied to the substrate to which the
first step of imparting an electroless plating reaction catalyst
was applied and in that the substrate to which the second step was
applied is immersed in an electroless plating bath so as to
selectively apply the electroless plating to the substrate. In our
further studies, however, we discovered that it is not possible to
achieve the desired removal or deactivation when using a laser beam
for removal or deactivation of the catalyst for some types of
substrates.
[0075] Therefore, the reason for this was searched for by taking
note of the characteristics of the substrate, whereupon it was
discovered for the first time that in the case of an alumina type
ceramic, there is a close relationship between the heat
conductivity of the substrate and the nonplated width of the
catalyst (corresponding to 6b in FIG. 7).
[0076] FIG. 14 is a graph showing the relationship between the
laser scanning speed and the nonplated width of the metal Pd
catalyst when changing the material of the cylindrical member 20
used in the second embodiment. Here, the laser scanning speed is
changed by changing the rotational speed of the cylindrical member
20. Further, the laser output was made 5 W.
[0077] Here, as the material of the cylindrical member, use was
made of 60% alumina (corresponding to heat conductivity of about
4.6 W/m.degree.C.) as A, 70% alumina (corresponding to heat
conductivity of about 6.3 W/m.degree.C.) as B, 80% alumina
(corresponding to heat conductivity of about 8.4 W/m.degree.C.) as
C, and 95% alumina (corresponding to heat conductivity of about
14.6 to 31.0 W/m.degree.C.) as D. The results are shown in FIG.
15.
[0078] As a result, if a good value of the heat conductivity of the
cylindrical member is 4.5 to 8.4 W/mK, it is learned that it is
possible to obtain the desired extent of catalyst deactivation by
adjusting the laser scanning speed. That is, when the heat
conductivity of the substrate is smaller than 4.5 W/mK, in the case
of an alumina type ceramic, the substrate itself becomes extremely
brittle and ends up no longer suitable for practical use. Further,
when larger than 14.5 W/mK, as shown in FIG. 14, a sufficient
nonplated width ends up not being able to be formed and, therefore,
the desired nonplated width ends up no longer able to be
formed.
[0079] Further, in the above embodiments, use was made of an argon
laser beam as the reaction-catalyst selective-imparting means, but
the present invention is not limited an argon laser beam. Any means
may be used if it causes deactivation of the catalyst applied to
the substrate, for example, a YAG laser, carbon dioxide gas laser,
excimer laser, electron beam, without regarding to continuous
emission or pulsed emission.
[0080] Further, in the embodiments, as the substrate, use was made
of a substrate comprised of a ceramic, but the substrate is not
limited to a ceramic. It may also be, for example, a resin the
substrate made of, for example, ABS, polypropylene, polycarbonate,
epoxy.
[0081] Further, in the above embodiments, grooves were formed in
the substrate by a laser, but it is possible not to form these
grooves, but merely to cause only deactivation of the catalyst by
the heat of a laser etc.
[0082] Still further, in the above embodiments, the wiring circuit
was formed by applying an electroless copper plating film, but the
invention may also be applied to any other kind of electroless
plating aside from electroless copper plating. For example, it is
possible to cause the formation of a resistor by forming an
electroless plating film with a large film resistance such as
electroless nickel-phosphorus, nickel-tungsten-phosphorus, etc.
[0083] Also, in the above embodiments, use was made of Pd as the
electroless plating reaction catalyst, but Ag, Pt, or anything else
serving as an electroless plating reaction catalyst may be also
used.
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