U.S. patent application number 11/431546 was filed with the patent office on 2006-11-23 for photoreduction method for metal complex ions.
This patent application is currently assigned to RIKEN. Invention is credited to Atsushi Ishikawa, Satoshi Kawata, Takuo Tanaka.
Application Number | 20060263541 11/431546 |
Document ID | / |
Family ID | 37448622 |
Filed Date | 2006-11-23 |
United States Patent
Application |
20060263541 |
Kind Code |
A1 |
Tanaka; Takuo ; et
al. |
November 23, 2006 |
Photoreduction method for metal complex ions
Abstract
The present invention provides a photoreduction method for metal
complex ions by which strict controllability is not required in the
control of its exposure amount, and a size of the metallic
structure to be produced can be controlled, besides there is no
fear of reducing spatial resolution of the size of the metallic
structure to be produced. The photoreduction method for metal
complex ions wherein a laser beam is beam-irradiated on a metal
complex ion dispersion element dispersed in a material to
photoreduce the metal complex ions thereby fabricating a metallic
structure, includes the steps of adding a predetermined coloring
matter to the material in which the metal complex ion dispersion
element is dispersed, and beam-irradiating the laser beam to the
material to which the predetermined coloring matter has been
added.
Inventors: |
Tanaka; Takuo; (Wako-shi,
JP) ; Ishikawa; Atsushi; (Wako-shi, JP) ;
Kawata; Satoshi; (Wako-shi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
RIKEN
Wako-shi
JP
|
Family ID: |
37448622 |
Appl. No.: |
11/431546 |
Filed: |
May 11, 2006 |
Current U.S.
Class: |
427/581 |
Current CPC
Class: |
C23C 18/143 20190501;
G03F 1/72 20130101 |
Class at
Publication: |
427/581 |
International
Class: |
C23C 18/14 20060101
C23C018/14 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2005 |
JP |
2005-139329 |
Claims
1. A photoreduction method for metal complex ions wherein a laser
beam is beam-irradiated on a metal complex ion dispersion element
dispersed in a material to photoreduce the metal complex ions
thereby fabricating a metallic structure, comprising: adding a
predetermined coloring matter to the material in which the metal
complex ion dispersion element is dispersed; and beam-irradiating
the laser beam to the material to which the predetermined coloring
matter has been added.
2. The photoreduction method for metal complex ions as claimed in
claim 1, wherein: the coloring matter has the peak of absorption
wavelength in the vicinity of about half of the wavelength of the
laser beam which is beam-irradiated to the material.
3. The photoreduction method for metal complex ions as claimed in
claim 1, wherein: the functional groups of the coloring matter have
not a reducing ability with respect to the metal complex ion
dispersion element dispersed into the material.
4. The photoreduction method for metal complex ions as claimed in
claim 1, wherein: the material is Au.sup.+ aqueous solution; the
coloring matter is any of P-Quaterphenyl, Stilbene 420, Coumarin
440, Coumarin 481, Coumarin 485, Coumarin 500, or Coumarin 515; and
a solution prepared by dissolving the coloring matter into a
dimethylformamide solvent is added to the Au.sup.+ aqueous
solution.
5. The photoreduction method for metal complex ions as claimed in
claim 4, wherein: a concentration of the coloring matter is 0.1 wt
% with respect to the dimethylformamide solvent.
6. The photoreduction method for metal complex ions as claimed in
claim 1, wherein: the material is Ag.sup.+ aqueous solution; the
coloring matter is any of Stilbene 420, Coumarin 440, Coumarin 504,
or Coumarin 515; and a solution prepared by dissolving the coloring
matter into an ethanol solvent is added to the Ag.sup.+ aqueous
solution.
7. The photoreduction method for metal complex ions as claimed in
claim 6, wherein: a concentration of the coloring matter is set out
at the amount of saturation with respect to the ethanol solvent.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a photoreduction method for
metal complex ions, and more particularly to a photoreduction
method for metal complex ions suitable for use in case of
fabricating a metallic structure by irradiating a laser beam to
photoreduce the metal complex ions.
[0003] 2. Description of the Related Art
[0004] In recent years, ultramicrofabrication technology such as
optical lithography technology, and optical disk manufacturing
technology wherein a light is applied is widely utilized, and such
technology has been studied in a variety of fields.
[0005] For instance, the most widely applied ultramicrofabrication
technology at present wherein a light is applied is the
above-described optical lithography technology. The optical
lithography technology is a backbone technology for manufacturing a
variety of electronic devices such as a semiconductor chip. The
technology relates to a massive copying technology applying a
photo-transferring technology in principle wherein a metal in a
specified region is dissolved, deposited, or removed finally in a
chemical manner, whereby a desired metallic pattern is fabricated
as a metallic structure.
[0006] On one hand, a manner for fabricating a metallic pattern by
irradiating directly a laser beam on a specified material is known
as a technology for fabricating a desired metallic pattern as a
metallic structure other than the above-described optical
lithography. More specifically, there have been proposed a manner
wherein a laser beam is beam-irradiated on a dispersion element
made of metallic nanoparticles, whereby the metallic nanoparticles
are molten and bound at the intermediate focus point of the laser
beam applied, so that a metallic pattern is fabricated as a
metallic structure; a manner wherein a laser beam is
beam-irradiated on metal complex ions, so that the metal complex
ions are photoreduced to deposit a metallic body, whereby a
metallic pattern is fabricated as a metallic structure, and the
like manners.
[0007] In the above-described manner wherein the metallic body is
deposited by photoreducing the metal complex ions, when the laser
beam is scanned while beam-irradiating the metal complex ions, it
is possible to fabricate an arbitrary metallic pattern in response
to the locus scanned as a metallic structure. Accordingly, its
applicable range is extremely wide, so that studies and
developments are made upon the manner in a variety of fields in
recent years.
[0008] The inventor of this application has made on a study as to a
manner wherein a multiphoton absorption process using an optical
system in which a femtosecond ultrashort pulse laser is applied
among lasers as a light source is utilized, whereby metal complex
ions are photoreduced, so that the metal complex ions are
photoreduced at only the intermediate focus point of the laser beam
in a three-dimensional space, and a three-dimensional metallic
structure is directly fabricated.
[0009] In the meantime, a technology wherein a laser beam is
beam-irradiated on metal complex ions to photoreduce the metal
complex ions thereby to fabricate a metallic structure involves
such a problem that a control of the light exposure is
difficult.
[0010] One of the major causes of a difficulty in controlling the
light exposure is in that a metal deposited as a result of
photoreduction of the metal complex ions causes the absorption
spectrum or the absorption sectional area of the material itself to
change, so that characteristic properties of the material which is
subjected to laser beam irradiation change momentarily as a result
of the laser beam irradiation. In other words, in case of
irradiating a light on a material, a constant exposure pattern
cannot be maintained so far as such control that optical intensity
of the light to be irradiated following to the precedent
irradiation is allowed to change timely in response to an amount of
the light which has been exposed until then is executed strictly.
However, it has been extremely difficult usually to execute such
strict control of the optical intensity.
[0011] Furthermore, in the case when a laser beam is
beam-irradiated to photoreduce metal complex ions to fabricate a
metallic structure, an absorption factor of light increases usually
with deposition of a metallic structure. In these circumstances,
there are many cases where the reaction proceeds explosively just
at the moment when an increased amount of the metallic structure
exceeds a certain threshold value. Thus, there is such a problem
that it is difficult to control a size of the metallic structure
produced.
[0012] Particularly, when the above-described explosive reaction
begins, the photoreduction of metal complex ions existing in the
vicinities of the intermediate focus point of a laser beam proceeds
at the same time. Hence, there is also such a problem that a
metallic structure produced becomes extremely large as compared
with a size of the intermediate focus point of a laser beam,
whereby its spatial resolution decreases.
OBJECT AND SUMMARY OF THE INVENTION
[0013] The present invention has been made in view of the
above-described various problems involved in the prior art, and an
object of the invention is to provide a photoreduction method for
metal complex ions by which no strict controllability is required
in control of an exposure amount, besides a size of a metallic
structure produced can be controlled, and further there is no fear
of decreasing spatial resolution of the size of the metallic
structure produced.
[0014] In order to achieve the above-described object, a
photoreduction method for metal complex ions according to the
present invention is the one wherein a laser beam is
beam-irradiated on a metal complex ion dispersion element dispersed
in a material such as a liquid, vapor, and a solid to photoreduce
the metal complex ions thereby fabricating a metallic structure,
including the step of adding a predetermined coloring matter to the
material in which the metal complex ion dispersion element is
dispersed, whereby photoreduction of the metal complex ions is
controlled to improve a process tolerance in case of fabricating
the metallic structure. As a result, for example, it becomes
possible to directly manufacture a three-dimensional metallic
structure having a nanomicron size.
[0015] More specifically, in the photoreduction method for the
metal complex ions according to the present invention, a specified
coloring matter is added to a metal complex ion dispersion element,
whereby an absorption spectrum and an absorption sectional area of
a non-processed material are maintained at constant, and it is
prevented to propagate energy of the laser beam to an area other
than the intermediate focus point of the laser beam, besides
photoreduction efficiency at the intermediate focus point of the
laser beam is improved.
[0016] Namely, the present invention may be a photoreduction method
for metal complex ions wherein a laser beam is beam-irradiated on a
metal complex ion dispersion element dispersed in a material to
photoreduce the metal complex ions thereby fabricating a metallic
structure, comprises the steps of adding a predetermined coloring
matter to the material in which the metal complex ion dispersion
element is dispersed; and beam-irradiating the laser beam to the
material to which the predetermined coloring matter has been
added.
[0017] Furthermore, the present invention may be the photoreduction
method for metal complex ions wherein the coloring matter has the
peak of absorption wavelength in the vicinity of about half of the
wavelength of the laser beam which is beam-irradiated to the
material.
[0018] Moreover, the present invention may be the photoreduction
method for metal complex ions wherein the functional groups of the
coloring matter have not a reducing ability with respect to the
metal complex ion dispersion element dispersed into the
material.
[0019] Still further, the present invention may be the
photoreduction method for metal complex ions wherein the material
is Au.sup.+ aqueous solution; the coloring matter is any of
P-Quaterphenyl, Stilbene 420, Coumarin 440, Coumarin 481, Coumarin
485, Coumarin 500, or Coumarin 515; and a solution prepared by
dissolving the coloring matter into a dimethylformamide solvent is
added to the Au.sup.+ aqueous solution.
[0020] Yet further, the present invention may be the photoreduction
method for metal complex ions wherein a concentration of the
coloring matter is 0.1 wt % with respect to the dimethylformamide
solvent.
[0021] Besides, the present invention may be the photoreduction
method for metal complex ions wherein the material is Ag.sup.+
aqueous solution; the coloring matter is any of Stilbene 420,
Coumarin 440, Coumarin 504, or Coumarin 515; and a solution
prepared by dissolving the coloring matter into an ethanol solvent
is added to the Ag.sup.+ aqueous solution.
[0022] In addition, the present invention may be the photoreduction
method for metal complex ions wherein a concentration of the
coloring matter is set out at the amount of saturation with respect
to the ethanol solvent.
[0023] Since the present invention is constituted as mentioned
above, it may provide such excellent advantageous effects that
strict controllability is not required in the control of its
exposure amount, and a size of the metallic structure to be
produced may be controlled, besides there is no fear of reducing
spatial resolution of the size of the metallic structure to be
produced.
[0024] The method of the present invention as described above may
be applied to optical memory technology, optical processing
technology, UV light molding technology, or optical lithography
technology. Accordingly, the present invention may be applied to
manufacturing of optical disks, laser processing equipment, optical
molding equipment or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0026] FIG. 1 is a schematic constructional explanatory view
showing an optical system used for experiments by the inventor of
this application;
[0027] FIG. 2 is an electron micrograph showing experimental
results made by the inventor of this application;
[0028] FIG. 3 is an electron micrograph showing experimental
results made by the inventor of this application;
[0029] FIG. 4 is an optical micrograph showing experimental results
made by the inventor of this application; and
[0030] FIG. 5 is an optical micrograph showing experimental results
made by the inventor of this application.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] In the following, an example of a manner of practice of the
photoreduction method for metal complex ions according to the
present invention will be described in detail by referring to the
accompanying drawings.
[0032] The photoreduction method for metal complex ions according
to the present invention is executed in such that a coloring matter
having a predetermined absorption wavelength and absorption
sectional area which is in such form that the coloring matter is
dissolved in a predetermined solvent (for example, water or an
organic solvent) is added to a material in which a metal complex
ion dispersion element has been dispersed, and then a laser beam is
beam-irradiated to the resulting product.
[0033] As an effective coloring matter in case of photoreducing
metal complex ions by the use of two-photon absorption process by
means of irradiation of a laser beam such as a femtosecond
ultrashort pulse laser, the coloring matter the absorption
wavelength of which has the peak in the vicinities of about half of
the laser beam to be beam-irradiated to a material; and the
absorption end on the long wavelength side expands up to
substantially red zone, in other words, there is no absorption in
near-infrared zone is preferred. For example, when a wavelength of
a laser beam to be beam-irradiated to a material has a wavelength
of around 800 nm, a coloring matter the absorption wavelength of
which has the peak in the vicinities of a wavelength of 350 to 450
nm; and the absorption end on the long wavelength side expands up
to substantially red zone, in other words, there is no absorption
in near-infrared zone is preferred.
[0034] Furthermore, concerning luminous efficacy of a coloring
matter, when the coloring matter having high luminous efficacy is
added to a material, an action for suppressing absorption
characteristics of the material can be obtained, while a coloring
matter having low luminous efficacy is added to a material, an
action for elevating absorption characteristics of the material may
be obtained. This is because the coloring matter having high
luminous efficacy absorbs once incident radiation energy, and then,
the most of the incident radiation energy is consumed as
fluorescence, so that photoreduction of metal complex ions is
obstructed. On the other hand, the coloring matter having low
luminous efficacy allows the incident radiation energy absorbed to
transit directly to metal ions, whereby either metal complex ions
are caused to be reduced, or discharged as heat, and then the heat
energy is again absorbed by metal ions. As a result, the metal
complex ions are reduced. Accordingly, when a coloring matter of
low luminous efficacy is added to a material, a reduction
efficiency of the metal complex ions is improved by a quantity
corresponding to that wherein an absorption amount of light
increases as a result of adding a coloring matter.
[0035] Moreover, when a coloring matter is selected, such coloring
matter wherein a functional group itself in an coloring matter
molecule has no reducing ability with respect to metal complex ions
is to be selected. This is because when the coloring matter itself
reduces the metal complex ions, the metal complex ions in the
material are reduced, so that an intended metallic structure cannot
be fabricated.
[0036] As a result of studying experimentally coloring matters, it
has been found that a gold structure can be manufactured by
beam-irradiating a laser beam on an Au.sup.+ aqueous solution being
a material prepared by adding the following coloring matters to
dimethylformamide solvent without requiring strict controllability
in the control of an exposure amount while controlling a size of
the resulting gold structure without decreasing the spatial
resolution. The Au.sup.+ aqueous solution is prepared by adding a
coloring matter such as p-Quaterphenyl, Stilbene 420, Coumarin 440,
Coumarin 481, Coumarin 485, Coumarin 500, or Coumarin 515 which has
been dissolved into the above-described dimethylformamide (DMF)
solvent to the Au.sup.+ aqueous solution (for example, an aqueous
solution of HAuCl.sub.4) as a material containing a metal complex
ion element in the case where gold ions are photoreduced as the
metal complex ions.
[0037] Furthermore, it has been found that a silver structure can
be manufactured by beam-irradiating a laser beam on an Ag.sup.+
aqueous solution being a material prepared by adding the following
coloring matters to ethanol solvent without requiring strict
controllability in the control of an exposure amount while
controlling a size of the resulting silver structure without
decreasing the spatial resolution. The Ag.sup.+ aqueous solution is
prepared by adding a coloring matter such as Stilbene 420, Coumarin
440, Coumarin 504, or Coumarin 515 which has been dissolved into
the above-described ethanol solvent to the Ag.sup.+ aqueous
solution (for example, an aqueous solution of AgNO.sub.3) as a
material containing a metal complex ion element in the case where
silver ions are photoreduced as the metal complex ions.
[0038] Concerning a concentration of a coloring matter, when
dimethylformamide is used as a solvent and an amount of a coloring
matter is made to be 0.1 wt % or less (a concentration of the
coloring matter with respect to the dimethylformamide solvent),
reduction of gold ions due to addition of the coloring matter is
not observed. Moreover, when the invention is compared with the
prior art, improvements are observed in resolution or a surface
condition of the gold structure fabricated in the photoreduction by
means of a laser beam.
[0039] On one hand, in the case where silver ions are photoreduced
as the above-described metal complex ions, ethanol may be used as a
solvent; and a concentration of a coloring matter may be set out to
the amount of saturation. The amount of saturation changes
dependent upon a coloring matter. For instance, it is 0.01 wt %
(the concentration of the coloring matter with respect to an
ethanol solvent) in case of Stilbene 420, it is 0.02 wt % (the
concentration of the coloring matter with respect to an ethanol
solvent) in case of Coumarin 440, itis 0.08 wt % (the concentration
of the coloring matter with respect to an ethanol solvent) in case
of Coumarin 504, and it is 0.02 wt % (the concentration of the
coloring matter with respect to an ethanol solvent) in case of
Coumarin 515. When a concentration of a coloring matter is set out
to its amount of saturation, improvements are observed in
resolution and a surface condition of the silver structure
fabricated in photoreduction by means of a laser beam in the
invention as compared with the prior art. On the other hand, no
reduction of silver ions due to addition of a coloring matter is
observed.
[0040] The experiments by which the above-described results are
obtained and which are made by the inventor of this application
will be described hereinbelow as examples 1 to 2.
[0041] In the experiments shown as examples 1 to 2, an optical
system 10 shown in FIG. 1 is used. The optical system 10 is
composed of a titanium-sapphire laser 12 as a femtosecond
ultrashort pulse laser, a condenser lens 14 for condensing the
laser beam output from the titanium-sapphire laser 12, and an XYZ
stage 18 for supporting a transparent glass substrate 16 with
respect to the laser beam output from the titanium-sapphire laser
12 and further being transferable freely in an X-axis, a Y-axis,
and a Z-axis directions (see the reference drawing corresponding to
FIG. 1 showing the XYZ-orthogonal coordinate system).
[0042] It is to be noted that the titanium-sapphire laser 12 has
800 nm central wavelength .lamda., 80 fs pulse width .DELTA.t, and
80 MHz repetition frequency f, respectively.
[0043] Moreover, on the substrate 16, a material containing a metal
complex ion dispersion element, and a material containing a metal
complex ion dispersion element added in such form that a coloring
matter is dissolved in a solvent are placed as a sample S.
[0044] In the construction as described above, the substrate 16 on
the top of which the sample S is placed is attached to the XYZ
stage 18, and when the XYZ stage 18 is driven in an arbitrary
direction along the X-axis direction, the Y-axis direction and the
Z-axis direction and further the intermediate focus point A of the
laser beam output from the titanium-sapphire laser 12 by means of
the condenser lens 14 is arbitrarily transferred to the Z-axis
direction in the sample S, metallic structures M are fabricated on
a locus of the above-described intermediate focus point in a
three-dimensional space.
EXAMPLE 1
[0045] FIG. 2 is an electron micrograph showing the results of
fabricating a silver structure in the case where a AgNO.sub.3
aqueous solution is used as the sample S, and the sample S is
relatively scanned with the laser beam output from the
titanium-sapphire laser 12 at a scanning speed 50 .mu.m/s by means
of the above-described optical system 10 wherein an illuminating
radiation power is 78.5 mW with respect to the sample S.
[0046] On one hand, FIG. 3 is an electron micrograph showing the
results of fabricating a silver structure in the case where a
mixture prepared by dissolving Coumarin 440 into an ethanol solvent
to a AgNO.sub.3 aqueous solution is used as the sample S, and the
sample S is relatively scanned with the laser beam output from the
titanium-sapphire laser 12 at a scanning speed 50 .mu.m/s by means
of the above-described optical system 10 wherein a concentration of
Coumarin 440 is 0.02 wt % with respect to the ethanol solvent,
while an illuminating radiation power is 14.3 mW with respect to
the sample S.
[0047] The locus of the laser beam output from the
titanium-sapphire laser 12 is transferred so as to fabricate an
inverted C-shaped silver structure outside a C-shaped structure in
both the experiments shown in FIGS. 2 and 3.
[0048] As is apparent from the comparison of FIG. 2 with FIG. 3, it
is found that sizes of both the silver structures are controlled at
high precision in the control of the exposure amount in the
experimental results shown in FIG. 3, and further its spatial
resolution is remarkably improved in spite of the fact that no
strict control is made in the control of the exposure amount.
EXAMPLE 2
[0049] FIG. 4 is an optical micrograph showing the results of
fabricating a gold structure in the case where a HAuCl.sub.4
aqueous solution is used as the sample S, and the sample S is
relatively scanned with the laser beam output from the
titanium-sapphire laser 12 at a scanning speed 50 .mu.m/s by means
of the above-described optical system 10 wherein an illuminating
radiation power is 142.9 mW with respect to the sample S.
[0050] On one hand, FIG. 5 is an optical micrograph showing the
results of fabricating a gold structure in the case where a mixture
prepared by dissolving Coumarin 481 into a dimethylformamide
solvent to a HAuCl.sub.4 aqueous solution is used as the sample S,
and the sample S is relatively scanned with the laser beam output
from the titanium-sapphire laser 12 at a scanning speed 50 .mu.m/s
by means of the above-described optical system 10.
[0051] In this case, a concentration of Coumarin 481 is 0.1 wt %
with respect to the dimethylformamide solvent, while an
illuminating radiation power is 39.3 mW with respect to the sample
S.
[0052] The locus of the laser beam output from the
titanium-sapphire laser 12 is transferred so as to fabricate an
inverted C-shaped gold structure outside a C-shaped structure in
both the experiments shown in FIGS. 4 and 5.
[0053] As is apparent from the comparison of FIG. 4 with FIG. 5, it
is found that sizes of both the gold structures are controlled at
high precision in the control of the exposure amount in the
experimental results shown in FIG. 5, and further its spatial
resolution is remarkably improved in spite of the fact that no
strict control is made in the control of the exposure amount.
[0054] It is to be noted that a dye-sensitization method utilized
in a photo conductor such as a photographic film which has been
heretofore known is a method for intending primarily to increase an
absorption sectional area of the photo conductor thereby improving
sensitivity and specifying wavelengths (cyan, magenta, yellow and
the like layers in case of color film).
[0055] On the other hand, the photoreduction method for metal
complex ions according to the present invention is quite different
from a conventional dye-sensitization method in that changes in the
absorption spectrum of a material with exposure to light is reduced
and an extent over which photoreduction effect due to the light
irradiated locally extends is limited in addition to that light
absorption characteristics of a material are allowed to change as
described above, whereby spatial resolution of the metal structure
may be improved. As a result, the following functions and
advantageous effects are obtained according to the present
invention.
[0056] (1) Changes in absorption wavelength and absorption
sectional area due to metal fine particles produced by exposure to
light may be suppressed by adding a coloring matter.
[0057] (2) In the present invention, a femtosecond ultrashort pulse
laser is used as a light source for taking place a photoreduction
reaction, so that the invention is particularly effective in a
system wherein a multiphoton process is used for absorption. When
such system as described is applied, it becomes possible that an
extent over which influences of a laser beam being condensed at the
intermediate focus point extend may be more spatially restricted,
and as a result, a metallic structure may be fabricated in finer
than a spot diameter of a laser beam decided by diffraction limit
of a light.
[0058] (3) When a femtosecond ultrashort pulse laser is used as a
light source thereby utilizing nonlinearity in a two-photon
absorption process, spatial resolution can be given to an
irradiation direction of the laser beam, and as a result, a
three-dimensional metallic structure can be easily fabricated.
[0059] (4) Since a coloring matter may be selected suitably so as
to accommodate to a wavelength or a desired absorption wavelength
of a light source, a tolerance in case of fabricating a metallic
structure becomes high.
[0060] (5) As a result of adding a coloring matter, energy
conversion efficiency of a light source can be improved, and as a
result, even when a laser beam is scanned at high speed, it becomes
possible to produce a metallic structure, so that the throughput
can be improved.
[0061] Furthermore, the above-described manner of practice and
examples may be modified as enumerated in the following paragraphs
(1) through (4).
[0062] (1) In the above-described manner of practice and examples,
although the invention is described with respect to the case where
a femtosecond ultrashort pulse laser is used as a light source, it
is not limited to the femtosecond ultrashort pulse laser as a
matter of course, but a variety of pulse lasers and continuous
lasers are applicable.
[0063] (2) In the above-described manner of practice and examples,
although a variety of coloring matters are shown, they are merely
exemplifications, and the other coloring matters may also be used
as a matter of course.
[0064] (3) In the above-described manner of practice and examples,
although the gold ions and the silver ions are described for
fabricating metallic structures, the metal complex ions to which
the present invention is applicable are not limited to the gold
ions and the silver ions as a matter of course, but the invention
may be applied to a variety of metal complex ions.
[0065] (4) The above-described manner of practice may be suitably
combined with the modifications described in the above-described
paragraphs (1) through (3), respectively.
[0066] It will be appreciated by those of ordinary skill in the art
that the present invention can be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof.
[0067] The presently disclosed embodiments are therefore considered
in all respects to be illustrative and not restrictive. The scope
of the invention is indicated by the appended claims rather than
the foregoing description, and all changes that come within the
meaning and range of equivalents thereof are intended to be
embraced therein.
[0068] The entire disclosure of Japanese Patent Application No.
2005-139329 filed on May 12, 2005 including specification, claims,
drawings and summary are incorporated herein by reference in its
entirety.
* * * * *