U.S. patent application number 14/978354 was filed with the patent office on 2016-06-30 for resin article having plating layer and manufacturing method thereof.
The applicant listed for this patent is CANON COMPONENTS, INC.. Invention is credited to Taisuke IWASHITA.
Application Number | 20160186323 14/978354 |
Document ID | / |
Family ID | 56163519 |
Filed Date | 2016-06-30 |
United States Patent
Application |
20160186323 |
Kind Code |
A1 |
IWASHITA; Taisuke |
June 30, 2016 |
RESIN ARTICLE HAVING PLATING LAYER AND MANUFACTURING METHOD
THEREOF
Abstract
There is provided with a method for manufacturing a resin
article having a plating layer, obtained by forming a plating layer
on a portion of the surface of a resin article. The surface of the
resin article is treated with a mask material solution. A portion
of the surface of the resin article is irradiated selectively with
ultraviolet rays such that it is possible to apply an electroless
plating catalyst to the portion of the surface of the resin
article. An electroless plating catalyst is applied to the portion
of the surface of the resin article irradiated with ultraviolet
rays. A plating layer is formed on the portion of the surface of
the resin article irradiated with ultraviolet rays, using
electroless plating.
Inventors: |
IWASHITA; Taisuke;
(Saitama-ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CANON COMPONENTS, INC. |
Saitama-ken |
|
JP |
|
|
Family ID: |
56163519 |
Appl. No.: |
14/978354 |
Filed: |
December 22, 2015 |
Current U.S.
Class: |
428/195.1 ;
427/553 |
Current CPC
Class: |
C23C 18/204 20130101;
C23C 18/1612 20130101; C23C 18/1605 20130101; C23C 18/2086
20130101; C23C 18/1608 20130101 |
International
Class: |
C23C 18/16 20060101
C23C018/16; C23C 18/18 20060101 C23C018/18 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 24, 2014 |
JP |
2014-261209 |
Claims
1. A method for manufacturing a resin article having a plating
layer, obtained by forming a plating layer on a portion of a
surface of a resin article, the method comprising: treating the
surface of the resin article with a mask material solution;
irradiating a portion of the surface of the resin article
selectively with ultraviolet rays such that it is possible to apply
an electroless plating catalyst to the portion of the surface of
the resin article; applying the electroless plating catalyst to the
portion of the surface of the resin article irradiated with
ultraviolet rays; and forming a plating layer on the portion of the
surface of the resin article irradiated with ultraviolet rays,
using electroless plating.
2. The method for manufacturing a resin article having a plating
layer according to claim 1, further comprising modifying the
surface of the resin article before the treating.
3. The method for manufacturing a resin article having a plating
layer according to claim 2, wherein the modifying further includes
treating the resin article with an alkali solution.
4. The method for manufacturing a resin article having a plating
layer according to claim 3, wherein a chemical adsorption group is
produced on the surface of the resin article due to the treatment
with the alkali solution.
5. The method for manufacturing a resin article having a plating
layer according to claim 1, wherein the surface of the resin
article includes at least one of an imide bond, an amide bond, and
an ester bond.
6. The method for manufacturing a resin article having a plating
layer according to claim 1, wherein the surface of the resin
article includes polyimide resin or polyamide resin.
7. The method for manufacturing a resin article having a plating
layer according to claim 1, wherein the mask material includes a
cation polymer.
8. The method for manufacturing a resin article having a plating
layer according to claim 1, wherein in the irradiating, the portion
of the surface of the resin article is irradiated with ultraviolet
rays of 243 nm or less.
9. The method for manufacturing a resin article having a plating
layer according to claim 1, wherein the irradiating is performed in
an atmosphere including at least one of oxygen and ozone.
10. The method for manufacturing a resin article having a plating
layer according to claim 1, wherein the applying includes bringing
an electroless plating catalyst solution or an electroless plating
catalyst ion solution into contact with the surface of the resin
article.
11. The method for manufacturing a resin article having a plating
layer according to claim 1, wherein the applying includes bringing
an electroless plating catalyst ion solution into contact with the
surface of the resin article and reducing the electroless plating
catalyst ions, and the electroless plating catalyst ions are
palladium complexes having a positive charge in at least a portion
thereof.
12. A resin article having a plating layer, manufactured using a
method comprising: treating a surface of a resin article with a
mask material solution; irradiating a portion of the surface of the
resin article selectively with ultraviolet rays such that it is
possible to apply an electroless plating catalyst to the portion of
the surface of the resin article; applying the electroless plating
catalyst to the portion of the surface of the resin article
irradiated with ultraviolet rays; and forming a plating layer on
the portion of the surface of the resin article irradiated with
ultraviolet rays, using electroless plating.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a resin article having a
plating layer and a manufacturing method thereof.
[0003] 2. Description of the Related Art
[0004] A resin article provided with a plating layer having a
predetermined pattern is useful as, for example, a wiring board, a
conductive film, or the like. A method in which electroless plating
is used has been known as a method for manufacturing such a resin
article having a plating layer.
[0005] For example, Japanese Patent Laid-Open No. 2008-094923
discloses a method for manufacturing a wiring board using surface
modification by means of ultraviolet rays. Specifically, first, the
entire surface of a cyclo-olefin polymer base material is
irradiated with ultraviolet rays emitted from an ultraviolet lamp,
and thus the surface of the base material is modified. An
electroless plating layer is likely to be deposited on the modified
region. Thereafter, an alkali degreasing treatment is performed on
the base material. It is thought that this treatment is performed
in order to improve adhesion with the catalyst ions or a binder
material that binds together catalyst ions and the base material,
the plating layer, and the like by cleaning the surface, and by
increasing hydrophilicity and forming fine surface roughness.
Furthermore, a conditioning treatment is performed on the base
material, and with this treatment, a binder material for binding
together catalyst ions and the base material is applied to the base
material. The catalyst ions are adsorbed on the binder material and
reduced to deposit a catalyst metal, whereafter electroless plating
is performed, and thereby a metal plating layer is formed on the
entire surface of the modified cyclo-olefin polymer material.
Finally, photolithography and etching are performed, whereby the
metal plating layer is patterned so as to have a desired
pattern.
[0006] Japanese Patent Laid-Open No. 2009-007613 discloses a method
for forming a metal thin film pattern on the surface of a polyimide
resin base material. Specifically, a resist pattern is formed on
the surface of the polyimide resin base material, and by performing
alkali modification, addition of fine metal particles, and
electroless plating on a portion exposed through an opening portion
of the resist pattern, a metal thin film is formed on the opening
portion of the resist pattern. The polyimide resin base material
has particularly excellent heat resistance compared to other resin
base materials, and in one example, has a Tg of 200.degree. C. or
more. Also, the polyimide resin base material has high mechanical
strength, high versatility, and can also be processed into a film,
for example. For these reasons, most flexible substrates are made
of polyimide resin.
SUMMARY OF THE INVENTION
[0007] According to an embodiment of the present invention, a
method for manufacturing a resin article having a plating layer,
obtained by forming a plating layer on a portion of a surface of a
resin article, includes: treating the surface of the resin article
with a mask material solution; irradiating a portion of the surface
of the resin article selectively with ultraviolet rays such that it
is possible to apply an electroless plating catalyst to the portion
of the surface of the resin article; applying the electroless
plating catalyst to the portion of the surface of the resin article
irradiated with ultraviolet rays; and forming a plating layer on
the portion of the surface of the resin article irradiated with
ultraviolet rays, using electroless plating.
[0008] According to another embodiment of the present invention, a
resin article having a plating layer is manufactured using a method
including: treating a surface of a resin article with a mask
material solution; irradiating a portion of the surface of the
resin article selectively with ultraviolet rays such that it is
possible to apply an electroless plating catalyst to the portion of
the surface of the resin article; applying the electroless plating
catalyst to the portion of the surface of the resin article
irradiated with ultraviolet rays; and forming a plating layer on
the portion of the surface of the resin article irradiated with
ultraviolet rays, using electroless plating.
[0009] Further features of the present invention will become
apparent from the following description of exemplary embodiments
(with reference to the attached drawings).
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a diagram illustrating a method for manufacturing
a resin article having a plating layer according to an
embodiment.
[0011] FIG. 2 is a flowchart for a method for manufacturing a resin
article having a plating layer according to an embodiment.
[0012] FIG. 3 is a diagram showing a mask used in an example and a
comparative example.
[0013] FIG. 4 is a diagram illustrating a method for manufacturing
a resin article having a plating layer according to an example and
a comparative example.
DESCRIPTION OF THE EMBODIMENTS
[0014] Photolithography and etching are needed in order to form a
plating layer having a desired pattern using the method disclosed
in Japanese Patent Laid-Open No. 2008-094923. Also, a resist
pattern needs to be formed using photolithography in the method
disclosed in Japanese Patent Laid-Open No. 2009-007613 as well. For
this reason, the methods disclosed in Japanese Patent Laid-Open No.
2008-094923 and Japanese Patent Laid-Open No. 2009-007613 are
problematic in terms of cost, and in that the environmental burden
is high since a large amount of waste liquid is produced.
[0015] According to an embodiment of the present invention, a
plating layer having a desired pattern can be formed on a resin
article at low cost.
[0016] The inventor knew of a technique in which the technique
disclosed in Japanese Patent Laid-Open No. 2008-094923 is adapted
such that instead of irradiating the entire surface of a resin
article with ultraviolet rays, a portion of the surface of the
resin article is selectively modified by being selectively
irradiated with ultraviolet rays in accordance with a desired
pattern. With this technique, a plating layer is selectively
deposited using electroless plating on the portion irradiated with
ultraviolet rays. That is, a plating layer having a desired pattern
can be obtained without using a photolithography step or an etching
step.
[0017] However, the inventor encountered a problem in that even if
such a technique is used, the shape of the resulting plating layer
is not stable in some cases. For example, the inventor found that
depending on conditions such as the type of the resin article used,
the plating layer is sometimes deposited also on a portion that was
not irradiated with ultraviolet rays. For example, in the case of
using a polyimide resin base material, when electroless plating was
performed after performing selective irradiation with ultraviolet
rays, the plating layer was deposited also on a portion that was
not irradiated with ultraviolet rays, and therefore a plating layer
having a desired pattern was not obtained.
[0018] The inventor speculates that the reason for this is as
follows. First, an example of the molecular structure of polyimide
will be shown below.
##STR00001##
[0019] Imide rings are opened by performing an alkali treatment on
polyimide, and thereby a carboxyl group COOH, which is a chemical
adsorption group, is produced as shown below.
##STR00002##
[0020] According to the method disclosed in Japanese Patent
Laid-Open No. 2008-094923, the alkali degreasing treatment is
performed, and conditioning treatment is performed using a binder
solution (conditioner) that is usually alkaline. In such a case, it
is thought that the imide rings of polyimide are opened by the
alkali degreasing treatment and the conditioning treatment, whereby
a chemical adsorption group is produced also on a portion that was
not irradiated with ultraviolet rays. Also, since carbonyl groups
(.dbd.O), which are chemical adsorption groups, are present in the
molecular structure of the polyimide, wettability is high. For this
reason, it is thought that the conditioner tends to be adsorbed on
the polyimide even if the imide rings are not opened.
[0021] As a result of examination, the inventor found that the mask
material on the region irradiated with ultraviolet rays can be
deactivated by treating the surface of the resin article with a
mask material solution and thereafter performing selective
irradiation with ultraviolet rays. When electroless plating was
performed thereafter, the plating layer was not deposited on the
portion that was not irradiated with ultraviolet rays.
[0022] Using this new method made it possible to perform selective
plating with good reproducibility even in the case of using resin
modified by an alkali solution, or resin with high wettability.
That is, a plating layer having a desired pattern could be formed
on a resin article at low cost without using a photolithography
step and an etching step.
[0023] Hereinafter, an embodiment according to which the present
invention can be applied will be described with reference to the
drawings. However, the scope of the present invention is not
limited to the following embodiment.
[0024] A method for manufacturing a resin article 100 having a
plating layer according to an embodiment of the present invention
includes a modifying step, a first applying step, an ultraviolet
ray irradiation step, a second applying step, and a plating step.
Hereinafter, each of these steps will be described with reference
to FIGS. 1 and 2.
[0025] Modifying Step
[0026] In the modifying step (step S210), treatment for modifying
at least a portion of a surface 120 of a resin article 110 is
performed on the resin article 110 that needs to be modified in
order to cause a plating layer to be deposited thereon in the
plating step. The modifying step makes it easier to deposit the
plating layer on the resin article 110 and makes it easier to
attach the mask material in the first applying step. In an
embodiment, the modifying step can be omitted for a resin article
on which the plating layer can be deposited in the plating step
even without performing modification, and to which the mask
material can be applied in the masking step. In 1a in FIG. 1, the
resin article 110 and the resin article surface 120 are shown. In
1b in FIG. 1, a modified resin article surface 130 of the resin
article 110 resulting from the modifying step is shown.
[0027] There is no particular limitation on the material of the
resin article 110. In particular, the method for manufacturing of
the present embodiment can be used for the resin article 110 having
a polyimide resin or a polyamide resin on its surface. Among these,
the polyimide resin has excellent heat resistance and strength, and
therefore soldering (including reflow) can be performed on a wiring
board obtained by forming a plating layer pattern on a polyimide
resin substrate.
[0028] The resin article 110, which includes a material that is
modified by an alkali solution, can also be used in the present
embodiment. In an embodiment, a chemical adsorption group is
produced on the surface of the resin article 110 due to hydrolysis
caused by the alkali treatment. Examples of the chemical adsorption
group include a hydroxyl group, a carbonyl group, a carboxyl group,
and the like. Also, in an embodiment, the surface of the resin
article 110 includes at least one of an imide bond, an amide bond,
and an ester bond.
[0029] In the present embodiment, a resin article 110 constituted
by a material having high wettability can also be used. In an
embodiment, the surface of the resin article 110 includes a
material having at least one of a hydroxyl group, a carbonyl group,
and a carboxyl group. A resin having this kind of functional group
has high wettability.
[0030] There is no particular limitation on the shape of the resin
article 110, and it can be in the form of a plate, film, or the
like, for example. Also, the resin article 110 may be constituted
by multiple resin materials, may have a structure in which multiple
resin materials are layered, or may be constituted by a compound
material including a coating structure obtained by coating the
surface of another material with a resin material.
[0031] Examples of modification methods include, but are not
limited to, irradiation with ultraviolet rays, acid treatment using
chromic acid or the like, and alkali treatment using sodium
hydroxide or the like. Also, it is possible to use two or more
modification methods in combination in the modification step.
[0032] In one embodiment, the resin article 110 is modified using
an alkali solution. That is, the resin article 110 has a property
in which bonds between molecules on the surface thereof are cut by
the alkali treatment. Examples of resin materials that are easily
modified by an alkali treatment include polyimide resin, polyamide
resin, polycarbonate resin, acrylic resin, and polyester resin.
[0033] For example, if polyimide resin is used as the resin article
110, when the alkali treatment is performed on the resin article
110, imide rings are opened, and carboxyl groups or carboxyl ions
are produced on the surface 120 of the resin article 110. Since the
carboxyl groups or carboxyl ions have a high affinity with the
later-described mask material, the mask material is more easily
adsorbed on the surface 120 in the first applying step (step S220).
For this reason, it is thought that after the mask material at a
region 150 irradiated with ultraviolet rays is deactivated,
electroless plating is more likely to be deposited on the surface
of the resin article 110 modified by the alkali treatment.
[0034] The alkali treatment may be performed on the entire resin
surface 120, or it may be selectively performed on a portion of the
resin surface that includes the region 150 irradiated with
ultraviolet rays, which will be described later. In this case, the
conditions for the alkali treatment may be selected as appropriate,
such that the plating layer is deposited on the region 150 that is
irradiated with ultraviolet rays and at which the mask material is
deactivated, and the plating layer is not deposited on the region
that is not irradiated with ultraviolet rays and at which the mask
material remains.
[0035] In an embodiment, the alkali treatment is performed by
immersing the resin article 110 in an alkali treatment solution.
For example, it is possible to use an aqueous solution of an alkali
metal hydroxide, an alkali earth metal hydroxide, or the like as
the alkali treatment solution. Specific examples of the alkali
treatment solution include an aqueous solution of sodium hydroxide,
an aqueous solution of potassium hydroxide, and the like. After the
alkali treatment, the resin article 110 may be cleaned by washing
with water, or the like.
[0036] First Applying Step
[0037] In the first applying step (S220), the mask material is
applied to the surface of the resin article 110 as shown in 1c in
FIG. 1. In 1c in FIG. 1, a region 140 of the resin article 110 to
which the mask material has been applied, resulting from the first
applying step, is shown. In the case of using a resin article 110
having a property such that the mask material attaches easily
thereto, the above-described modifying step may be omitted. In an
embodiment, each oxygen atom existing on the modified surface is
high in electro-negativity and strongly attracts electrons in the
molecule, and therefore has a negative charge. In another
embodiment, imide bonds (--CONCO--) in primary chains of the
polyimide resin undergo imide ring opening due to the alkali
treatment in the modifying step, and thus have a negative charge.
The mask material may be thus applied to the surface of the resin
having a negative charge or an adsorption group.
[0038] The mask material may include an ion polymer as a component.
Ion polymers include cation polymers, anion polymers, and non-ion
polymers. Specifically, a mask material that easily attaches to the
surface of the resin article 110 can be used. For example, in an
embodiment in which a resin article 110 having a surface with a
negative charge is used, a cation polymer is used as the mask
material. Thus, a mask material having a charge opposite to that of
the surface of the resin article 110 can be used as a mask material
that easily attaches to the surface of the resin article 110. In an
embodiment, the mask material is in the form of a solution.
Application of the mask material can be performed by treating the
surface of the resin article 110 with the mask material solution,
and for example, it can be performed by bringing the mask material
solution into contact with the surface of the resin article. In an
embodiment, the first applying step may be performed by immersing
the resin article 110 in the mask material solution. In another
embodiment, the first applying step may be performed by spraying
the mask material solution onto the resin article 110 or coating
the resin article 110 with the mask material solution.
[0039] It is thought that the mask material is deactivated due to
the mask material being selectively irradiated with ultraviolet
rays in a later step. Then, in an even later step, a catalyst is
adsorbed on the surface of the resin article 110, and thus an
electroless plating layer is deposited at that region. As long as a
desired property is obtained, the mask material may remain on the
resin article having a plating layer after all of the steps are
complete, and there is no need to include a step of removing the
mask material.
[0040] Ultraviolet Ray Irradiation Step
[0041] In an ultraviolet ray irradiation step (step S230), the
resin article 110 to which the mask material has been applied is
selectively irradiated with ultraviolet rays, as shown in 1d in
FIG. 1. In 1d in FIG. 1, the region 150 that was selectively
irradiated with ultraviolet rays, and the region 140 that was not
irradiated with ultraviolet rays and to which a mask material was
applied are shown. In the ultraviolet ray irradiation step, a
region on at least a portion of the surface of the resin article
110 to which the mask material has been applied is irradiated with
ultraviolet rays such that an electroless plating catalyst can be
applied to the portion of the surface of the resin article 110 to
which the mask material has been applied. It is thought that by
performing irradiation with ultraviolet rays, the mask material
applied to the surface of the resin article 110 is deactivated.
[0042] In an embodiment, the resin article 110 is irradiated with
ultraviolet rays in an atmosphere including at least one of oxygen
and ozone. As a specific example, the resin article 110 can be
irradiated with ultraviolet rays in air. In another embodiment, in
order to further promote the deactivation of the mask material,
irradiation is performed in an atmosphere including ozone.
[0043] For example, upon performing irradiation with ultraviolet
rays having a specific wavelength or less that can decompose oxygen
in an atmosphere including oxygen, the oxygen in the atmosphere is
decomposed to produce ozone. Furthermore, active oxygen is produced
in the process of decomposing ozone.
[0044] The energy of a photon having a specific wavelength can be
represented by the following equation.
E=Nhc/.lamda.(KJmol.sup.-1)
[0045] N=6.022.times.10.sup.23 mol.sup.-1 (Avogadro's number)
[0046] h=6.626.times.10.sup.-37 KJs (Planck constant)
[0047] c=2.988.times.10.sup.8 ms.sup.-1 (speed of light)
[0048] .lamda.=light wavelength (nm)
[0049] Here, the binding energy of an oxygen molecule is 490.4
KJmol.sup.-1. The light wavelength is approximately 243 nm when
converted from the binding energy based on the equation for the
energy of photons. This indicates that the oxygen molecules in the
atmosphere absorb ultraviolet rays having a wavelength of 243 nm or
less and are decomposed. As a result, ozone O.sub.3 is produced.
Furthermore, during decomposition of ozone, active oxygen is
produced. At this time, if ultraviolet rays having a wavelength of
310 nm or less are present, ozone is efficiently decomposed to
produce active oxygen. Furthermore, ultraviolet rays having a
wavelength of 254 nm decompose ozone most efficiently.
O.sub.2+h.nu. (243 nm or less).fwdarw.O(3P)+O(3P)
O.sub.2+O(3P).fwdarw.O.sub.3 (ozone)
O.sub.3+h.nu. (310 nm or less).fwdarw.O.sub.2+O(1D) (active
oxygen)
[0050] O(3P): oxygen atom in ground state
[0051] O(1D): oxygen atom in excited state (active oxygen)
[0052] There is no particular limitation on the method for
irradiation with ultraviolet rays, and for example, it is possible
to use an ultraviolet lamp, an ultraviolet LED, an ultraviolet
laser, or the like. In an embodiment, the region 150 to be
irradiated is irradiated with ultraviolet rays emitted from an
ultraviolet lamp or the like through a quartz chromium mask in
which a desired pattern is formed. In another embodiment, the
region 150 to be irradiated with ultraviolet rays is scanned with
ultraviolet rays using ultraviolet rays from an ultraviolet laser
or the like.
[0053] In the present embodiment, the portion of the surface of the
resin article 110 on which the electroless plating is to be
deposited is selectively irradiated with ultraviolet rays. It is
thought that the mask material applied to the surface of the resin
article 110 is deactivated at the portion irradiated with
ultraviolet rays, and as a result, an electroless plating catalyst
can be applied thereto. For example, by performing irradiation with
ultraviolet rays via a mask having an ultraviolet ray transmission
portion with a shape corresponding to the plating pattern to be
deposited, the region 150 to be irradiated with ultraviolet rays
can be selectively irradiated with ultraviolet rays. An example of
the mask is shown in FIG. 3. The photomask 300 shown in FIG. 3
includes a substrate 310 that transmits ultraviolet rays, and a
metal thin film 320 that is provided on the substrate 310 and does
not transmit ultraviolet rays. The metal thin film 320 is patterned
so as to have an opening having a shape that corresponds to the
region 150 to be irradiated with ultraviolet rays.
[0054] There is no particular limitation on the wavelength of the
ultraviolet rays, and a wavelength that promotes deactivation of
the mask material applied to the resin surface is selected. In an
embodiment, the wavelength of the ultraviolet rays is 243 nm or
less. Due to the wavelength being 243 nm or less, the deactivation
of the mask material on the surface of the resin article 110 is
further promoted. Ultraviolet rays with a wavelength of 243 nm or
less can decompose oxygen in the atmosphere, and can produce ozone
and active oxygen.
[0055] There is no particular limitation on the irradiation amount
of ultraviolet rays, and the irradiation amount can be selected as
appropriate such that the mask material of the region 150
irradiated with ultraviolet rays is deactivated and the plating is
selectively deposited on the region 150 irradiated with ultraviolet
rays. In general, it is thought that the larger the irradiation
amount of ultraviolet rays is, that is, the higher the intensity of
the ultraviolet rays is or the longer the irradiation time is, the
more the deactivation of the mask material at the region 150
irradiated with ultraviolet rays advances and the easier it is for
the plating to be deposited. However, the inventor confirmed, by
means of an experiment, that the deposition of the plating
deteriorates in some cases if the irradiation amount of ultraviolet
rays exceeds an appropriate amount. The inventor speculates that
the reason for this is that the modified layer on the surface of
the resin article 110 falls off when the deactivation of the mask
material advances and the ultraviolet rays reach the surface of the
resin article 110.
[0056] In an embodiment, the cumulative irradiation amount of
ultraviolet rays at the primary wavelength can be 600 mJ/cm.sup.2
or more, or 800 mJ/cm.sup.2 or more. In an embodiment, the
cumulative irradiation amount at the primary wavelength is 1200
mJ/cm.sup.2 or less. In the present specification, unless otherwise
stated, the irradiation amount and irradiation intensity of
ultraviolet rays indicate values at the primary wavelength. In the
present specification, the primary wavelength indicates the
wavelength with the highest intensity in a range of 243 nm and
less. Specifically, in the case of using a low-voltage mercury
lamp, the primary wavelength is 185 nm.
[0057] The conditions for deactivating the mask material may change
depending on the type of the resin article 110, the existence of
modification of the resin surface and the state thereof, the level
of contamination of the surface of the resin article 110, the type
of the mask material, the thickness of the mask material, the type
of the plating solution, the concentration, temperature, pH, and
deterioration over time of the plating solution, variation in the
output of the ultraviolet lamp, or the like. In this case, it is
sufficient that the irradiation amount of ultraviolet rays is
determined as appropriate with reference to the foregoing
values.
[0058] Second Applying Step
[0059] In the second applying step (step S240), an electroless
plating catalyst is applied to the surface of the resin article 110
irradiated with ultraviolet rays. Specifically, as shown in 1e in
FIG. 1, an electroless plating catalyst is applied to the region
150 irradiated with ultraviolet rays.
[0060] The electroless plating catalyst can be applied in
accordance with a conventionally-known method. For example, the
electroless plating catalyst can be applied by using the following
two steps.
[0061] The catalyst is applied by bringing a catalyst ion solution
into contact with the surface of the resin article 110. In an
embodiment, the catalyst may be applied by immersing the resin
article 110 in the catalyst ion solution. In another embodiment,
the catalyst may be applied by spraying the catalyst ion solution
onto the resin article 110 or coating the resin article 110 with
the catalyst ion solution.
[0062] The catalyst ions are reduced by immersing the resin article
110 in a solution containing a reducing agent. Thus, the catalyst
is deposited. Examples of the reducing agent include hydrogen gas,
dimethylamine borane, sodium borohydride, and the like.
[0063] An electroless plating catalyst is used which easily
attaches to locations at which the mask material on the surface of
the resin article 110 is deactivated, and which is not likely to
attach to the mask material on the resin article 110. For example,
the electroless plating catalyst can be applied by using an
electroless plating catalyst having a charge opposite that of the
surface of the resin article 110 after the mask material has been
deactivated. In this case, the electroless plating catalyst
selectively attaches to the region 150 irradiated with ultraviolet
rays. On the other hand, the electroless plating catalyst does not
attach to the region 140 that was not irradiated with ultraviolet
rays and to which the mask material was applied. Specific examples
of the electroless plating catalyst include a cation catalyst such
as an activator solution (product name ELFSEED ES-300, available
from JCU Corporation) containing a palladium complex (e.g., a
palladium (II)-basic amino acid complex) having a positive charge
in at least a portion thereof. A palladium-basic amino acid complex
disclosed in WO 2007/066460 can be used as another example of a
palladium-basic amino acid complex. It is possible to perform the
second applying step (step S240) by using an activator solution for
electroless plating including this kind of electroless plating
catalyst. This kind of palladium complex having a positive charge
in at least a portion thereof is likely to interact with the
chemical adsorption group produced on the surface of the resin
article 110 after the mask material is deactivated.
[0064] Specific examples of the reducing agent include a cation
activating agent such as an accelerator solution (product name:
ELFSEED ES-400, available from JCU Corporation).
[0065] Plating Step
[0066] In the plating step (step S250), the resin article 110 to
which the electroless plating catalyst has been applied is immersed
in the electroless plating solution. In if in FIG. 1, a resin
article 100 having a plating layer, in which a plating layer 170
has been deposited on the region 150 irradiated with ultraviolet
rays, is shown.
[0067] There is no limitation on the specific method for
electroless plating. Examples of electroless plating that can be
used include electroless plating using a formalin-based electroless
plating bath, and electroless plating using hypophosphorous acid as
the reducing agent, which has a slow depositing speed but is easy
to handle. Also, the plating layer 170 may be formed using a
high-speed electroless plating method in order to form a thicker
plating layer. Further specific examples of electroless plating
include electroless copper plating, electroless copper nickel
plating, and zinc oxide plating.
[0068] Electroless plating according to such a method can be
performed using, for example, an electroless Cu--Ni plating
solution (product name: AISL-520, available from JCU Corporation).
In the case of using hypophosphorous acid as the reducing agent,
copper nickel plating in which nickel is used is performed in order
to give the plating layer self-catalyzing properties.
[0069] The plating layer 170 formed using electroless plating in
this way is often thin, and therefore the thickness of the plating
layer 170 may be increased by further performing electrolytic
plating. In 1g in FIG. 1, the plating layer 180 whose thickness has
been increased by further performing electrolytic plating is shown.
Examples of the material of the metallic layer provided using
electrolytic plating include, but are not limited to, copper,
nickel, copper-nickel alloy, zinc oxide, zinc, silver, cadmium,
iron, cobalt, chromium, nickel-chromium alloy, tin, tin-lead alloy,
tin-silver alloy, tin-bismuth alloy, tin-copper alloy, gold,
platinum, rhodium, palladium, and palladium-nickel alloy. Also,
silver or the like may be deposited on the plating layer 170 by
displacement plating.
[0070] According to the method of the present embodiment, the
plating layer 170 is deposited on the region 150 irradiated with
ultraviolet rays by performing electroless plating. On the other
hand, even if electroless plating is performed, the plating layer
170 is not deposited on the region that was not irradiated with
ultraviolet rays. For example, the plating layer is not deposited
on the region adjacent to the region 150 irradiated with
ultraviolet rays. Thus, according to the method of the present
embodiment, the plating layer 170 can be selectively deposited with
good reproducibility on the region 150 irradiated with ultraviolet
rays.
EXAMPLES
Example 1
[0071] A polyimide plate (product name: Kapton EN200, thickness: 50
.mu.m, available from DuPont-Toray Co., Ltd.) was used as a resin
article 410. Table 1 shows the steps performed in Example 1.
TABLE-US-00001 TABLE 1 Step Treatment conditions Alkali treatment
50.degree. C., 10 seconds Mask material application 50.degree. C.,
2 minutes treatment Ultraviolet ray irradiation 10 minutes Catalyst
application treatment 50.degree. C., 5 minutes Reduction treatment
35.degree. C., 4 minutes Electroless copper nickel plating
60.degree. C., 5 minutes (Washing with water is performed as needed
after each step)
[0072] Modifying Step
[0073] The resin article 410 and the resin article surface 420 are
shown in 4a in FIG. 4. First, the resin article 410 was subjected
to an alkali treatment. In 4b in FIG. 4, a modified resin article
surface 430 of the resin article 410 resulting from the modifying
step is shown. Specifically, the resin article 410 was immersed for
10 seconds in an aqueous solution of sodium hydroxide adjusted so
as to be 50.degree. C. and 0.90 mol/L, which is an alkali treatment
solution used in a Cu--Ni plating solution set "AISL" available
from JCU Corporation. Thereafter, the resin article 410 was washed
with water.
[0074] Mask Material Applying Step (First Applying Step)
[0075] Next, after undergoing the alkali treatment, the resin
article 410 was subjected to a mask material application treatment.
In 4c in FIG. 4, the surface 440 of the resin article 410 to which
the mask material has been applied, resulting from the mask
material applying step, is shown. Specifically, the resin article
410 was immersed for 2 minutes at 50.degree. C. using a conditioner
solution used in the Cu--Ni plating solution set "AISL", available
from JCU Corporation. Thereafter, the resin article 410 was washed
with water.
[0076] Ultraviolet Ray Irradiation Step
[0077] Next, the portion on which the plating layer was to be
formed on the resin article 410 was irradiated with ultraviolet
rays via a photomask in air. In 4d in FIG. 4, a region 450
selectively irradiated with ultraviolet rays is shown. The other
region was not irradiated with ultraviolet rays. The ultraviolet
ray irradiation conditions were as follows.
[0078] Low-voltage mercury lamp: UV-300 (primary wavelengths: 185
nm, 254 nm), available from Samco Corporation
[0079] Irradiation distance: 3.5 cm
[0080] Illuminance at irradiation distance of 3.5 cm: 5.40
mW/cm.sup.2 (254 nm), and 1.35 mW/cm.sup.2 (185 nm)
[0081] Irradiation time: 10 minutes
[0082] The cumulative exposure amount at this time was 1.35
mW/cm.sup.2.times.600 seconds=about 810 mJ/cm.sup.2.
[0083] Catalyst Applying Step (Second Applying Step)
[0084] Next, the resin article 410 irradiated with ultraviolet rays
was subjected to a catalyst application treatment. As shown in 4e
in FIG. 4, the electroless plating catalyst is applied to the
surface of the resin article 410 that was irradiated with
ultraviolet rays. The electroless plating catalyst binds to the
region 450 irradiated with ultraviolet rays. In 4e in FIG. 4, a
region 460 to which the electroless plating catalyst was applied is
shown. Specifically, the resin article 410 was immersed for 5
minutes at 50.degree. C. using an activator solution (product name:
ELFSEED ES-300, available from JCU Corporation). At this time, the
activator solution was used at three times the concentration
specified by the manufacturer. Thereafter, the resin article 410
was washed with water. Thus, the catalyst ions were applied.
Furthermore, the resin article 410 was immersed for 4 minutes at
35.degree. C. using the accelerator solution (product name: ELFSEED
ES-4, available from JCU Corporation). Thereafter, the resin
article 410 was washed with water. Thus, the catalyst ions were
reduced.
[0085] Electroless Plating Step
[0086] Next, the resin article 410 resulting from the reduction
treatment was subjected to electroless copper nickel plating.
Specifically, the resin article 410 was heated to 60.degree. C. and
immersed for 5 minutes using the electroless Cu--Ni plating
solution (product name: AISL-520, available from JCU Corporation).
Thereafter, the resin article 410 was washed with water.
[0087] A resin article 400 having a plating layer shown in 4f in
FIG. 4 was produced using the treatments above. The resin article
400 having a plating layer was observed, and it was found that the
plating layer 470 was formed on the region 450 irradiated with
ultraviolet rays, but no plating layer was formed on the portion
that was not irradiated with ultraviolet rays. Thus, it can be
understood that the plating layer can be formed selectively with
good reproducibility according to the method of Example 1.
Example 2
[0088] The resin article 410 having a plating layer was produced in
a manner similar to that of Example 1, except for the fact that the
resin article 410 was irradiated with ultraviolet rays for 7
minutes in the ultraviolet ray irradiation step. In Example 2 as
well, the plating layer 470 was formed on the region 450 irradiated
with ultraviolet rays and no plating layer was formed on the
portion that was not irradiated with ultraviolet rays.
Example 3
[0089] The resin article having a plating layer 410 was produced in
a manner similar to that of Example 1, except for the fact that the
resin article 410 was irradiated with ultraviolet rays for 3
minutes in the ultraviolet ray irradiation step. In Example 3, the
plating layer 480 was formed only on a portion of the region 450
irradiated with ultraviolet rays. Also, no plating layer was formed
on the portion that was not irradiated with ultraviolet rays. In 4g
in FIG. 4, the resin article 410 on which the plating layer 480 was
formed in the present example is shown.
Example 4
[0090] The resin article 410 having a plating layer was produced in
a manner similar to that of Example 1, except for the fact that the
resin article 410 was irradiated with ultraviolet rays for 5
minutes in the ultraviolet ray irradiation step. In Example 4, the
plating layer 490 was not formed in narrow parts of the region 450
irradiated with ultraviolet rays. Also, no plating layer was formed
on the portion that was not irradiated with ultraviolet rays. In
the present example, in 4h in FIG. 4, the resin article 410 on
which the plating layer 490 was formed is shown.
Example 5
[0091] The resin article having a plating layer 410 was produced in
a manner similar to that of Example 1, except for the fact that the
resin article 410 was irradiated with ultraviolet rays for 15
minutes in the ultraviolet ray irradiation step. In Example 5, the
plating layer was not sufficiently formed on the region 450
irradiated with ultraviolet rays. Also, no plating layer was formed
on the portion that was not irradiated with ultraviolet rays.
[0092] As described above, it was confirmed that the plating layer
is sufficiently deposited on the portion of the resin article
selectively irradiated with ultraviolet rays by performing
irradiation with ultraviolet rays for an appropriate amount of
time. The inventor also found that if there is originally-present
damage on the resin surface or the resin is damaged in a step of
generating the plating layer, or the like, the plating layer tends
to spread out in the form of spikes at the damaged portion. On the
other hand, the inventor confirmed that the plating layer tends to
withdraw inward from the boundary along recessions and protrusions
caused by damage in the plating layer produced using the methods of
Examples 1 and 2. Due to these characteristics, with the methods of
Examples 1 and 2, it is possible to prevent the occurrence of
defects such as a wiring pattern short circuiting.
Comparative Example 1
[0093] First, the resin article 410 was subjected to ultraviolet
ray irradiation for 10 minutes using a procedure similar to that of
Example 1. Thereafter, the resin article 410 irradiated with
ultraviolet rays was subjected to an alkali treatment.
Specifically, the resin article 410 was immersed for 2 minutes in
an aqueous solution of sodium hydroxide adjusted so as to be
50.degree. C. and 0.90 mol/L, which is an alkali treatment solution
used in the Cu--Ni plating solution set "AISL", available from JCU
Corporation. Thereafter, the resin article 410 was washed with
water.
[0094] Furthermore, the resin article 410 subjected to the alkali
treatment was subjected to a conditioning treatment. Specifically,
the resin article 410 was immersed for 2 minutes at 50.degree. C.
using a conditioner solution used in the Cu--Ni plating solution
set "AISL", available from JCU Corporation. At this time, the
conditioner solution that was used was diluted to one-tenth the
concentration designated by the maker. If the resin article is
polyimide, the conditioner tends to remain in the portion that was
not irradiated with ultraviolet rays due to the alkali treatment in
the previous step. For this reason, the conditioner used was
diluted in order to achieve selectivity by causing the conditioner
to remain on the portion irradiated with ultraviolet rays and
making it easier to rinse off the conditioner on the non-irradiated
portion. Thereafter, the resin article 410 was washed with water.
Next, the resin article 410 irradiated with ultraviolet rays was
subjected to a catalyst application treatment. Specifically, the
resin article 410 was immersed for 2 minutes at 50.degree. C. using
the activator solution (product name: AISL-ACT, available from JCU
Corporation). Thereafter, the resin article 410 was washed with
water. Furthermore, the resin article 410 was immersed for 2
minutes at 40.degree. C. using the accelerator solution (product
name: acceleration treatment solution for AISL-520, available from
JCU Corporation). Thereafter, the resin article 410 was washed with
water. Thus, a catalyst ion reduction treatment was performed.
Thereafter, electroless copper nickel plating was performed in a
manner similar to that of Example 1. In Comparative Example 1, the
plating layer was formed on both the portion irradiated with
ultraviolet rays and the portion that was not irradiated with
ultraviolet rays. Table 2 shows the steps carried out in
Comparative Example 1.
TABLE-US-00002 TABLE 2 Step Treatment Conditions Ultraviolet ray
irradiation 10 minutes Alkali treatment 50.degree. C., 2 minutes
Conditioning treatment 50.degree. C., 2 minutes Catalyst
application treatment 50.degree. C., 2 minutes Reduction treatment
40.degree. C., 2 minutes Electroless copper nickel 60.degree. C., 5
minutes. plating (Washing with water was performed as needed after
each step)
[0095] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0096] This application claims the benefit of Japanese Patent
Application No. 2014-261209, filed Dec. 24, 2014, which is hereby
incorporated by reference herein in its entirety.
* * * * *