U.S. patent application number 14/143231 was filed with the patent office on 2014-06-12 for sensor, sensor system, portable sensor system, method of analyzing metal ions, mounting substrate, method of analyzing plating preventing chemical species, method of analyzing produced compound, and method of analyzing monovalent copper chemical species.
This patent application is currently assigned to NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY. The applicant listed for this patent is HITACHI CHEMICAL COMPANY, LTD., NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY. Invention is credited to Yutaka HAYASHI, Yuji KAWANISHI, Hidehiro NAKAMURA, Tooru NAKAMURA.
Application Number | 20140158555 14/143231 |
Document ID | / |
Family ID | 40511434 |
Filed Date | 2014-06-12 |
United States Patent
Application |
20140158555 |
Kind Code |
A1 |
NAKAMURA; Hidehiro ; et
al. |
June 12, 2014 |
SENSOR, SENSOR SYSTEM, PORTABLE SENSOR SYSTEM, METHOD OF ANALYZING
METAL IONS, MOUNTING SUBSTRATE, METHOD OF ANALYZING PLATING
PREVENTING CHEMICAL SPECIES, METHOD OF ANALYZING PRODUCED COMPOUND,
AND METHOD OF ANALYZING MONOVALENT COPPER CHEMICAL SPECIES
Abstract
This invention provides a sensor having such a structure that
the area in which a sensor electrode comes into contact with a
liquid, a mist or a gas containing an analyte has been previously
specified. The sensor comprises at least an electroconductive first
electrode, an electroconductive second electrode, electroconductive
first and second wirings connected to the first and second
electrodes, and an insulating part for insulating the first and
second wirings from each other and from a liquid, a mist or a gas
containing the analyte. The insulating part is formed of an organic
material. In the first and second electrodes, at least the surface,
which comes into contact with a liquid, a mist or a gas containing
the analyte, is formed of a material which is insoluble in a liquid
or a mist containing the analyte, or is not attacked by a gas
containing the analyte.
Inventors: |
NAKAMURA; Hidehiro;
(Tsukuba-shi, JP) ; NAKAMURA; Tooru; (Ushiku,
Ibaraki, JP) ; HAYASHI; Yutaka; (Tsukuba, JP)
; KAWANISHI; Yuji; (Tsukuba, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND
TECHNOLOGY
HITACHI CHEMICAL COMPANY, LTD. |
Tokyo
Tokyo |
|
JP
JP |
|
|
Assignee: |
NATIONAL INSTITUTE OF ADVANCED
INDUSTRIAL SCIENCE AND TECHNOLOGY
Tokyo
JP
HITACHI CHEMICAL COMPANY, LTD.
Tokyo
JP
|
Family ID: |
40511434 |
Appl. No.: |
14/143231 |
Filed: |
December 30, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12680447 |
Mar 26, 2010 |
8648605 |
|
|
PCT/JP2008/067384 |
Sep 26, 2008 |
|
|
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14143231 |
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Current U.S.
Class: |
205/789 |
Current CPC
Class: |
G01N 27/423 20130101;
G01N 27/42 20130101 |
Class at
Publication: |
205/789 |
International
Class: |
G01N 27/42 20060101
G01N027/42 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2007 |
JP |
P2007-255997 |
Dec 27, 2007 |
JP |
P2007-337684 |
Claims
1. A method of analyzing a compound produced from a copper plating
solution during copper plating, comprising: contacting the copper
plating solution that is used for the copper plating with at least
a first electrode and a second electrode; applying a voltage whose
level varies over time between the first and second electrodes;
identifying the compound produced from the copper plating solution
during the copper plating in a voltage range in which a variation
in a current flowing between the first and second electrodes is
observed; and analyzing the concentration of the compound produced
from the copper plating solution during the copper plating based on
the maximum value of the current or the integral value of the
current with respect to the voltage.
2. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 1,
further comprising: providing a third electrode that supplies at
least a portion of the potential thereof to the first electrode or
the second electrode at the same polarity or different polarities;
and contacting the copper plating solution with the third
electrode.
3. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 1,
wherein the voltage range is from +0.2 V to +2.0 V.
4. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 2,
wherein the voltage range is from +0.2 V to +2.0 V.
5. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 1,
wherein the concentration of the compound produced is analyzed
based on a value obtained by subtracting the maximum value of the
current or the integral value of the current with respect to the
voltage, which is obtained from an initial make-up bath copper
plating solution before being used, instead of the copper plating
solution that is being used, from the maximum value of the current
or the integral value of the current with respect to the voltage,
which is obtained from the copper plating solution that is used for
the copper plating.
6. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 2,
wherein the concentration of the compound produced is analyzed
based on a value obtained by subtracting the maximum value of the
current or the integral value of the current with respect to the
voltage, which is obtained from an initial make-up bath copper
plating solution before being used, instead of the copper plating
solution that is being used, from the maximum value of the current
or the integral value of the current with respect to the voltage,
which is obtained from the copper plating solution that is used for
the copper plating.
7. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 5,
wherein the temperature of the initial make-up bath copper plating
solution and the temperature of the copper plating solution that is
being used are measured, the rate of change of the maximum value of
the current or the integral value of the current with respect to
the voltage of the initial make-up bath copper plating solution,
which is separately analyzed, according to the temperature is used
to convert the maximum value of the current or the integral value
of the current with respect to the voltage of the analyzed initial
make-up bath copper plating solution into a value corresponding to
the temperature of the copper plating solution that is being used,
and the concentration of the compound produced is analyzed based on
a value obtained by subtracting the converted value from the
maximum value of the current or the integral value of the current
with respect to the voltage of the copper plating solution used for
copper plating.
8. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 6,
wherein the temperature of the initial make-up bath copper plating
solution and the temperature of the copper plating solution that is
being used are measured, the rate of change of the maximum value of
the current or the integral value of the current with respect to
the voltage of the initial make-up bath copper plating solution,
which is separately analyzed, according to the temperature is used
to convert the maximum value of the current or the integral value
of the current with respect to the voltage of the analyzed initial
make-up bath copper plating solution into a value corresponding to
the temperature of the copper plating solution that is being used,
and the concentration of the compound produced is analyzed based on
a value obtained by subtracting the converted value from the
maximum value of the current or the integral value of the current
with respect to the voltage of the copper plating solution used for
copper plating.
9. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 5,
wherein a copper plating solution obtained by making an analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble is used.
10. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 6,
wherein a copper plating solution obtained by making an analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble is used.
11. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 5,
wherein a copper plating solution obtained by making an analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble with a chemical species which forms a
hardly soluble compound with the analysis preventing material is
used.
12. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 6,
wherein a copper plating solution obtained by making an analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble with a chemical species which forms a
hardly soluble compound with the analysis preventing material is
used.
13. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 5,
wherein a copper plating solution obtained by making an analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble with cations which form a hardly soluble
salt with the analysis preventing material is used.
14. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 6,
wherein a copper plating solution obtained by making an analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble with cations which form a hardly soluble
salt with the analysis preventing material is used.
15. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 9,
wherein, after a pre-process selected from a precipitation process
and/or a filtering process is performed to make the analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble, the analysis is performed.
16. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 11,
wherein, after a pre-process selected from a precipitation process
and/or a filtering process is performed to make the analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble, the analysis is performed.
17. The method of analyzing a compound produced from a copper
plating solution during copper plating according to claim 13,
wherein, after a pre-process selected from a precipitation process
and/or a filtering process is performed to make the analysis
preventing material, which is included in the initial make-up bath
copper plating solution or the copper plating solution that is
being used, hardly soluble, the analysis is performed.
Description
CLAIM OF PRIORITY
[0001] The present application claims priority from Japanese
Application No. P2007-255997, filed on Sep. 28, 2007, and Japanese
Application No. P2007-337684, filed on Dec. 27, 2007, in the
Japanese Patent Office, the contents of each of which are
incorporated herein by reference. This application is a divisional
of application Ser. No. 12/680,447, filed on Mar. 26, 2010, now
allowed, the contents of which are incorporated herein by
reference. application Ser. No. 12/680,447 is a 371 of
International Application No. PCT/JP2008/067384, filed Sep. 26,
2008.
TECHNICAL FIELD
[0002] The present invention relates to a metal ion sensor that is
used to analyze metal ions, a sensor system, a portable sensor
system, and a method of analyzing metal ions, and more
particularly, to a metal ion sensor structure, a sensor system, a
method of analyzing a chemical species, and a mounting
substrate.
BACKGROUND ART
[0003] In recent years, the earth's environment has greatly
affected by manufacture, a consuming society, and business
activity. The influence is incomputable. For example, air
pollution, water pollution, and soil pollution due to wastes cause
the deterioration of an ecosystem by a food chain and global
warming. Therefore, CSR, environment, business, and laws and
regulations that are inseparable from the business activity have
become important. For this reason, it becomes to be important to
develop a technique capable of contributing to the improvement and
conservation of the environment. For example, the importance of the
analysis of metal ions, such as copper ions, cadmium ions, lead
ions, chrome ions, and mercury ions, which are important in a
manufacturing field and an environmental field has increased. From
this point of view, a "surface potential measurement-type sensor
device" has been proposed as an analysis technique (for example,
see Patent Document 1). This technique uses the analysis function
of a self-assembled film. The analysis principle is as follows:
when ion atoms are attracted to a self-assembled film provided at
the leading end of an electrode, a work function varies from a
position corresponding to the Fermi level of a base before and
after the ion atoms are attracted, and the variation in potential
is measured based on a reference electrode to analyze the
concentration of a very small amount of solution. It is considered
that this technique has the following effects:
[0004] 1) The potential variation reaches a specific potential
corresponding to the attracted ions (it is possible to selectively
perform analysis corresponding to a molecular film structure);
[0005] 2) The specific potential does not depend on the area of the
electrode (since a current is not measured, a measurement system is
simple and there is a strong possibility that the size of the
system will be reduced);
[0006] 3) The time required for the potential to reach the specific
potential is proportional to the area of the electrode (it is
possible to perform analysis in a wide range); and
[0007] 4) It is possible to repeatedly perform analysis a maximum
of twenty times by EDTA cleaning.
[0008] The inventors has pursued analysis using an electrochemical
analysis method in which the self-assembled film is not provided on
the electrode, according to an analysis target. However, the
inventors found that this method had the following problems,
similar to the self-assembled sensor.
[0009] When this technique is applied to a complex system sample
(hereinafter, simply referred to as a "complex system") in which a
material included in an analyte is not known or the concentration
of the material is not known even though the kind of material is
known, a technique for more selectively analyzing the material is
needed. Therefore, it is indispensable to increase the number of
electrodes for analyzing a multi-component system, and a
multi-layer wiring technique capable of reducing the size of a
system even when the number of measuring electrodes is increased is
more advantageous than a technique for forming a single-layer
wiring substrate. That is, an effectively manufacturing technique
capable of corresponding to the multi-layer wiring technique as
well as the single-layer wiring substrate is required for the
measuring substrate. In recent years, an inorganic substrate, such
as a glass, ceramic, or mica substrate, has been used as an
electrochemical measuring substrate, and a vacuum process, such as
sputtering or vapor deposition, has been performed to form wiring
lines. This process is effective in miniaturizing the wiring line,
but it is difficult to reduce manufacturing costs and form a
multi-layer structure.
[0010] An example in which an organic substrate used in the printed
circuit board industry is used as the measuring substrate has not
been known.
[0011] As the main multi-layer wiring technique generally known in
the printed circuit board industry, there is a through hole
connection technique which is a combination of drilling and a
plating process, which has generally been known. However, in the
technique, since holes are formed in all layers, there is a limit
in the accommodation of wiring lines. In order to reduce the volume
of holes provided in a connection portion, a build-up technique has
generally been used which repeatedly performs the formation of an
insulating resin composition layer, boring, and the formation of a
circuit. The build-up technique is mainly divided into a laser
method and a photolithography method. The laser method radiates a
laser beam to form holes in the insulating resin composition layer.
The photolithography method uses a photosensitive hardener
(photoinitiator) for the insulating resin composition layer, puts a
photomask on the insulating resin composition layer, and performs
exposure and development to form holes. In addition, in order to
further reduce manufacturing costs and increase density, some
interlayer connection methods have been proposed. Among them, a
method capable of omitting boring and a conductive layer plating
process has drawn attention. In the method, first, a conductive
paste is printed on wiring lines on a substrate to form a bump, an
interlayer connection insulating material and a metal layer in a B
stage are arranged, and the bump is inserted into a molding resin
by a press to be electrically connected to a metal layer. The
method of inserting the bump has been published in the scientific
society or the newspaper, and has widely been known in the printed
circuit board industry (for example, see Non-Patent Documents 1 and
2).
[0012] There is a collectively laminating method as a more
efficient forming method. A wiring plate has been proposed which is
integrally formed by printing holes, a connection conductor, and
wiring lines on a ceramic body, which is called a green sheet
before sintering, aligning them, and applying heat and pressure.
However, since the plate is shrunken by about 20%, numerical
stability is low. In addition, since the plate is made of an
inorganic material, it is expensive. As a collectively laminating
method that uses an organic material and does not require a boring
process, there is a collectively laminated substrate conceived by
the inventors including Nakamura (for example, see Patent Document
2). This method uses an insulating substrate made of a
thermoplastic liquid crystal polymer.
[0013] In the method of forming a multi-layer structure, for
example, plating, etching, printed wiring, and a wiring transfer
method have been used to form a fine wiring line.
[0014] In the analysis of a complex system, it is very difficult to
directly contact a sensor with a liquid to be extracted and
analyzed and selectively analyze target metal ions. Even when a
component system has been known, other metal ions preventing
analysis or an analysis preventing material is included in the
target metal ions when the concentration of the metal ions is
selectively analyzed, which significantly reduces the possibility
of analysis. The analysis of a monovalent copper chemical species
is given as an example. In this case, the monovalent copper
chemical species is a simple monovalent copper ion, a monovalent
copper ion complex, or a composite chemical species including
monovalent copper.
[0015] For example, the analysis of the monovalent copper chemical
species is used to identify protein and sugar.
[0016] In addition, in an electrochemical measuring method in a
filled via copper plating solution that covers a structure portion
having a hole with the bottom with copper and forms a flat wiring
layer, the measurement of the potential of a constant current at a
cathode is used to evaluate a filled via property. However, it is
difficult to qualitatively and/or quantitatively analyze a
monovalent copper chemical species even though there is a plurality
of metal ions or an analysis preventing material and the principle
of a measurement method thereof is considered.
[0017] For the filled via copper plating solution, the monovalent
copper ion deteriorates the filled via property a little, and it is
preferable to qualitatively and quantitatively analyze the filled
via copper plating solution. However, it is not certain that the
plating preventing chemical species deteriorating the filled via
property is the monovalent copper ion, the monovalent copper ion
complex, the composite chemical species including monovalent
copper, or a produced compound included in the plating solution
that is used. When there is a large amount of divalent copper or an
analysis preventing material, it is difficult to qualitatively and
quantitatively analyze a target plating preventing chemical species
and a produced compound selectively.
[0018] In the invention, the electrochemical analysis method means
a method which immerses a plurality of electrodes in a liquid to be
analyzed, applies a voltage or a current between the electrodes,
and observes a variation in the current or the voltage. In the
method, a plurality of strip-shaped gold thin films that are
adhered on a glass substrate and extend in one direction
substantially in parallel to each other are used as the
electrodes.
[0019] Since the electrode is connected to a measuring device, a
portion of the electrode needs to protrude from the liquid to be
analyzed to the outside. The contact area of the electrode with the
liquid to be analyzed is changed by, for example, the depth of
immersion and the inclination of the substrate during immersion. In
this case, the reproducibility of the analysis result is not
ensured. In particular, there is a problem in the reproducibility
of quantitative analysis. Therefore, it is important to insulate a
wiring line from, for example, a liquid, mist, or gas, which is an
analysis target, separate the electrode from the wiring line, and
ensure a predetermined area of the electrode. It is important to
provide an insulating portion on the wiring line, but it is
difficult to effectively form the layer on a glass substrate at a
low cost.
[0020] It is difficult to repeatedly use the electrode for a long
time since it is contaminated, modified, and plated in the analysis
process, and the electrode is regarded as an article of
consumption. Therefore, in order to frequently use an inorganic
substrate, such as a glass substrate, having electrodes formed
thereon for field water quality analysis for managing chemicals and
a work environment in the manufacturing line, it is preferable that
the substrate be manufactured at a low cost.
[0021] The inventors have conducted an examination on the
application of an organic substrate to electrochemical measurement
and surface potential. As a result of the examination, the organic
substrate has two main problems. The first problem is chemical
resistance. When a liquid to be extracted and analyzed is a strong
acid or a strong alkali, ions or molecules that prevent or increase
an analysis function are likely to be generated from the organic
substrate during analysis. In addition, the decomposition of an
organic material forming the organic substrate, the remaining
solvent, various kinds of additives, an ion material attracted
during a wiring process, and a material absorbed from the air cause
the generation of the analysis preventing ions or molecules.
[0022] The second problem is heat resistance. This is because it is
necessary to form a carbon layer, which is an inert layer, such as
a gold or platinum layer, on the electrode in the electrochemical
analysis. (It is preferable that the carbon layer be formed of 100%
of carbon. However, when an additive, such as a binder or a
dispersant, is used in the component, impurities are removed such
that the purity of the additive is approximately 100%. Hereinafter,
a layer that includes carbon as a component and serves as an inert
layer is referred to as a carbon including layer, and a material is
referred to as a carbon including material. In addition, coating
with the carbon including layer is referred to as carbon coating.
The shape of carbon may be a particle or a carbon filament). For
example, in general, a DLC method has been used to form the carbon
including layer in which the content of carbon is approximately
100%, in terms of characteristics thereof, and a base material is
exposed to a high temperature of 200.degree. C. or more. In
high-accuracy analysis, in a vapor deposition process and/or a
sputtering process, the precipitation of impurities that are
decomposed and generated prevents analysis. Therefore, an organic
resin having high chemical resistance and high heat resistance,
such as polyimide or liquid crystal polymer, in the method of
forming a multi-layer wiring substrate is considered as an
insulating material for a substrate for a sensor. However, this
material is not necessarily selected, but there is a difficulty in
a reduction in cost and the degree of recognition or spread in the
industry. In particular, it is considered that the decomposition of
an organic material at the adhesion interface or the bonding
interface between an insulating material and a buried electrode
causes the most serious problem. In this case, a liquid to be
extracted and analyzed is infiltrated into the interface, which
results in a variation in the area of the electrode during
measurement or when the electrode is repeatedly used.
[0023] In the analysis of a complex system, that is, in
high-accuracy analyze, a pre-process is needed. In many case, a
complicated pre-process is needed. For example, an organic ligand,
a filtering method, and a colorimetric method using absorbance
measurement are performed to analyze monovalent copper (for
example, see Non-Patent Document 3). This analysis method is
relatively simple and has high selectivity. However, in order to
put this analysis method to practical use, it is necessary to
reduce the time required for a pre-process or analysis. [0024]
Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No.
2006-058020 [0025] Patent Document 2: WO/2003/056889 [0026]
Non-Patent Document 1: Hiroshi Ohira, other two persons: Proposal
of Printed Circuit Board by New Manufacturing Process (B2it), 9th
Proceedings of JIEP (Japan Institute of Electronics Packaging)
Annual Meeting, ISSN0916-0043, 15A-10, PP.55-56, (March, 1995)
[0027] Non-Patent Document 2: Takahiro Mori, other five persons:
Application and Miniaturization of Substrate by Interlayer
Connection Technique Using Bump, 10th Proceedings of JIEP Annual
Meeting, ISSN0916-0043, 15A-09, PP.79-80, (March, 1996) [0028]
Non-Patent Document 3: "Introduction of Research Results in
Technology Techno Report (2002)", Osaka Municipal Technical
Research Institute, Published July, 2003, p. 14
(URL:http://www.omtri.city.osaka.jp/)
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0029] The present invention has been made in view of the problems
according to the related art, and the problem of the invention is
to achieve the following objects.
[0030] That is, an object of the invention is to provide a sensor
having a structure that defines the contact area of an electrode of
the sensor with a liquid, mist, or gas including an analyte in
advance.
[0031] In order to define the area of the electrode, the invention
provides a sensor having a structure which includes a wiring line
that is electrically connected to the electrode of the sensor and
prevents the elution of a wiring material from the wiring line to a
liquid or mist including an analyte, the leakage or discharge of
current from the wiring line to the liquid, mist, or gas including
the analyte, and the electrical interference between a plurality of
wiring lines.
[0032] An object of the invention is to provide a sensor having an
electrode structure in which a material forming an insulating
substrate for a sensor does not need to have chemical resistance
and heat resistance as high as an inorganic insulating material
such as glass or ceramics. Another object of the invention is to
provide a sensor having an electrode structure that does not
require an alignment process and a masking process for ensuring
insulating property between electrodes, in order to form a carbon
including layer forming the electrode structure according to the
invention so as to be separated between the electrodes, if
necessary.
[0033] A still another object of the invention is to provide an
analysis method capable of qualitatively and quantitatively
analyzing a monovalent copper chemical species, and a plating
preventing chemical species or a produced compound included in
copper plating solution that is used, using an electrochemical
method, a surface potential measuring method, a colorimetric
method, or combinations thereof.
[0034] A yet another object of the invention is to provide an
analysis method that qualitatively and quantitatively analyzes a
monovalent copper chemical species from a plurality of metal ions
or a liquid of a complex system including an analysis preventing
material, or qualitatively and quantitatively analyzes a plating
preventing chemical species or a chemical species of a produced
compound included in a plating solution including an analysis
preventing material or a large amount of bivalent copper by
selectively performing an electrochemical method and a surface
potential measuring method, using the sensor according to the
invention or other types of sensors.
[0035] A still yet another object of the invention is to provide a
sensor system that includes the sensor and is capable of integrally
and continuously performing a pre-process with high efficiency.
[0036] A still yet another object of the invention is to provide a
portable sensor system that includes the sensor and can be carried
to a desired place and easily analyze a very small amount of an
analyte in a short time on the spot.
Means for Solving the Problem
[0037] In the invention, as a means for preventing the elution of a
wiring material from the connection wiring line that is
electrically connected to the electrode of the sensor to a liquid
or mist including an analyte, the leakage or discharge of current
from the connection wiring line to the liquid, mist, or gas
including the analyte, and the electrical interference between a
plurality of connection wiring lines, an insulating portion that is
made of an organic material and insulates connection wiring lines
electrically connected to a plurality of electrodes and insulates
the connection wiring lines from the liquid, mist, or gas including
the analyte is provided.
[0038] In the invention, as a means for defining the contact area
of the electrode of the sensor with the liquid, mist, or gas
including the analyte in advance, a coverlay that has openings
through which the plurality of electrodes provided on an organic
insulating substrate are exposed to the outside and covers the
connection wiring lines is provided.
[0039] The coverlay is a protectively layer and protects wiring
lines drawn through portions other than the exposed portions and
electrodes that are not exposed. The protective layer prevents a
mechanical damage and ensures insulating property between the
electrodes and between the connection wiring lines. The protective
layer can prevent a leakage current between the wiring lines due to
humidity and a short circuit due to the residue of solder cream
print during the mounting of electronic parts. For example, an
insulating film with an adhesive layer, a resist ink, or a resist
film is used as the coverlay.
[0040] The material forming the insulating substrate used in the
sensor according to the invention is not limited to an organic
material with heat resistance that can correspond to a vacuum
process. In addition, in order to select a manufacturing process
from a multi-layer forming process including many organic materials
that cannot correspond to the vacuum process, the inventors uses a
means that provides a carbon including layer on an insulating
substrate made of an organic material using a method of forming the
carbon including layer in which the organic material forming the
insulating substrate does not need to have particularly high heat
resistance and high chemical resistance.
[0041] For this reason, a low-temperature vapor deposition method
is needed. As a low-temperature carbon vapor deposition, a carbon
vapor deposition method called tough carbon using an ion cluster
beam has been known (for example, see Japanese Patent No. 3660866).
In this method, since vapor deposition is performed at a low
temperature of 100.degree. C., it is possible to significantly
reduce the mixture of impurities from a base material or
contamination (hereinafter, simply referred to as "contamination").
Therefore, a glass epoxy resin may be used as a candidate of the
organic base material.
[0042] In addition, a method using print paste is effective. As the
print paste, the technique and paste disclosed in Japanese Patent
Application Laid-Open (JP-A) No. 2006-147202, 2007-165708, or
2007-165709 may be used. Specifically, carbon paste manufactured by
HITACHI CHEMICAL CO., LTD is preferably used. As a method of
printing the carbon paste, an application method using a syringe or
an ink jet method is effective. The hardening temperature is in the
range of 160.degree. C. to 210.degree. C., and may be appropriately
set according to the heat resistance of a base material.
[0043] That is, for example, in order to improve mechanical and
thermal characteristics, a mixture of an organic material and an
inorganic material may be used, which is also included in the scope
of the invention.
[0044] In the electrochemical measurement and the potential
measurement, it is important to ensure an insulating property in
addition to chemical resistance and heat resistance. In particular,
the stability of the insulating property is very important to high
resolution of measured data or the reproducibility of measured
data.
[0045] However, in any method, when a base material is selected and
a carbon including layer is formed on the entire surface of the
base material by various vapor deposition methods and various
printing methods, it is necessary to prepare a separate mask in
order to ensure insulating property between the electrodes, and an
alignment is needed. Therefore, there is a difficulty in achieving
an effective manufacturing method capable of corresponding to
minute electrodes. The invention provides means for solving the
problems.
[0046] In the invention, as an analysis means that selectively
performs the identification and the quantitative analysis of a
monovalent copper chemical species from a plurality of metal ions
or a liquid of a complex system including an analysis preventing
material, a plating preventing chemical species, or a chemical
species of a produced compound included in a plating solution,
which is being used, including an analysis preventing material or a
large amount of bivalent copper, a method includes contacting a
liquid of a complex system or a copper plating solution used for
copper plating with at least a first electrode and a second
electrode, applying a voltage whose level varies over time between
the first and second electrodes, identifying a monovalent copper
chemical species, a plating preventing chemical species, or a
chemical species of a produced compound in the voltage range in
which the maximum value of the current flowing between the first
and second electrodes, and analyzing the concentration of the
monovalent copper chemical species, the plating preventing chemical
species, or the chemical species of the produced compound based on
the maximum value of the current within the voltage range or the
integral value of the current with respect to the voltage.
[0047] That is, the characteristics of the invention are as
follows.
[0048] (1) A sensor includes: first and second conductive
electrodes; first and second conductive wiring lines that are
respectively connected to the first and second conductive
electrodes; and an insulating portion that insulates the first
wiring line from the second wiring line and insulates the first and
second wiring lines from a liquid, mist, or gas including an
analyte. The insulating portion is made of an organic material, and
at least the surfaces of portions of the first and second
electrodes that come into contact with the liquid, the mist, or the
gas including the analyte are made of a material that is insoluble
by the liquid or the mist including the analyte or a material that
is not eroded by the gas including the analyte.
[0049] (2) The sensor according to (1) may further include: a third
electrode that supplies at least a portion of the potential thereof
to the first electrode or the second electrode at the same polarity
or different polarities; and a third wiring line that is connected
to the third electrode. At least the surface of a portion of the
third electrode that comes into contact with the liquid, the mist,
or the gas including the analyte is made of a material that is
insoluble by the liquid, the mist, or the gas including the analyte
or a material that is not eroded by the gas including the
analyte.
[0050] Gold, platinum, or carbon is given as an example of the
material that is insoluble in the liquid or the mist including the
analyte and is not eroded by the gas including the analyte.
[0051] (3) The sensor according to (2) may further include an
insulating portion that is made of an organic material and
insulates the third wiring line from the first and second wiring
lines, and the liquid, the mist, or the gas including the
analyte.
[0052] (4) In the sensor according to (1), the first and second
wiring lines may be connected to corresponding connection
terminals.
[0053] (5) In the sensor according to (2), the third wiring line
may be connected to a connection terminal
[0054] (6) In the sensor according to (1), a plurality of sets of
the first electrode and the first wiring line and a plurality of
sets of the second electrode and the second wiring line may be
provided.
[0055] (7) In the sensor according to (2), a plurality of sets of
the first electrode and the first wiring line, a plurality of sets
of the second electrodes and the second wiring lines, and a
plurality of sets of the third electrodes and the third wiring
lines may be provided.
[0056] (8) The sensor according to (4) may further include: an
insulating substrate that is made of an organic material; at least
one electrode group that includes the first and second electrodes
and is arranged on the insulating substrate; at least one
connection wiring line group that is electrically connected to the
electrode group and has at least one layer including the first and
second wiring lines; and at least one connection terminal group
that is electrically connected to the connection wiring line
group.
[0057] (9) The sensor according to (5) may further include: an
insulating substrate that is made of an organic material; at least
one electrode group that includes the first and second electrodes
and the third electrode and is arranged on the insulating
substrate; at least one connection wiring line group that is
electrically connected to the electrode group and has at least one
layer including the first, second, and third wiring lines; and at
least one connection terminal group that is electrically connected
to the connection wiring line group.
[0058] (10) The sensor according to (8) or (9) may further include
at least a coverlay that is provided on the insulating substrate,
has openings through which the electrode group is exposed to the
outside, and covers the connection wiring line group. At least the
coverlay and the insulating substrate form the insulating portion
that insulates the connection wiring line group and insulates the
connection wiring line from the liquid, the mist, or the gas
including the analyte.
[0059] (11) In the sensor according to (10), each of the openings
of the coverlay may be provided so as to be arranged inside each
electrode of the electrode group.
[0060] (12) In the sensor according to (10), each of the openings
of the coverlay may be provided so as to be arranged outside each
electrode of the electrode group that is exposed through the
opening.
[0061] (13) The sensor according to (11) or (12) may further
include at least a carbon including layer that is provided on the
insulating substrate. The carbon including layer may be formed on
the surface of the coverlay surface and at least a portion of the
surface of each electrode disposed in the opening.
[0062] (14) In the sensor according to any one of (10) to (13), the
opening of the coverlay may be formed such that the diameter
thereof is increased from the upper surface to the lower
surface.
[0063] (15) In the sensor according to any one of (10) to (13), the
coverlay may be formed such that the area of the opening in the
upper surface is less than the area of the opening in the lower
surface.
[0064] (16) In the sensor according to any one of (10) to (13), the
coverlay may include at least two layers, that is, a coverlay film
and an adhesive layer. The edge of an opening in the adhesive layer
and the edge of an opening of the coverlay film may be arranged at
the same position, or the edge of the opening in the adhesive layer
may be arranged outside the edge of the opening of the coverlay
film.
[0065] (17) In the sensor according to any one of (1) to (16), gold
may be coated on at least a portion of the outermost surface of at
least one of the first to third electrodes.
[0066] (18) In the sensor according to (17), any one of a carbon
including layer, a nickel layer, and a palladium layer may be
provided as a base layer of the outermost layer.
[0067] (19) In the sensor according to any one of (1) to (18), an
organic monolayer may be formed on at least a portion of the
outermost surface of at least one of the first to third
electrodes.
[0068] (20) In the sensor according to (19), the organic monolayer
may have a substituent group including at least one selected from
the group consisting of chlorine, bromine, sulfur, nitrogen, and
oxygen on the surface thereof.
[0069] (21) A sensor system includes: the sensor according to (4)
or (5), or any one of (8) to (20); and a measuring device that
measures voltage-current characteristics between at least two
electrodes among the electrodes of the sensor.
[0070] (22) The sensor system according to (21) may further include
a connector and a wiring member that electrically connect the
sensor and the measuring device.
[0071] (23) The sensor system according to (21) or (22) may further
include an analysis liquid container.
[0072] (24) The sensor system according to any one of (21) to (23)
may further include: a blocking plate that is provided between the
connector and the electrode or the electrode group which comes into
contact with a liquid or mist including the analyte and prevents
the evaporation of a liquid including the analyte from the liquid
level.
[0073] (25) In the sensor system according to any one of (21) to
(23), the distance from the connector to the electrode or the
electrode group may be 3 mm or more.
[0074] (26) A portable sensor system includes: the sensor according
to (4) or (5), or any one of (8) to (20); a measuring device that
measures voltage-current characteristics between at least two
electrodes among the electrodes of the sensor; and a portable
container that accommodates at least the sensor and the measuring
device.
[0075] (27) The portable sensor system according to (26) may
further include a connector and wiring lines that are accommodated
in the portable container and electrically connect the sensor and
the measuring device.
[0076] (28) In the sensor according to (1) or (2), at least one of
a set of the first electrode and the first wiring line, a set of
the second electrode and the second wiring line, and a set of the
third electrode and the third wiring line may include one
conductive line and an organic material serving as the insulating
portion which covers a portion of the conductive line, and a
portion of the conductive line exposed from the organic material
may be used as the electrode.
[0077] (29) In the sensor according to (28), the exposed portion
may be a cut surface of the conductive line which is covered with
the organic material.
[0078] (30) In the sensor according to (28), the conductive line
may have another portion that is exposed from the organic material
and is separated from the portion exposed from the organic
material, and another exposed portion of the conductive line may be
used as the connection terminal.
[0079] (31) A sensor includes: an insulating substrate; an
electrode group that includes a reference electrode, a counter
electrode, and a working electrode arranged on the same surface of
the insulating substrate; a connection wiring line group that
includes one or more layers and is electrically connected to the
electrode group; and a measuring terminal group that is
electrically connected to the connection wiring line group.
[0080] (32) In the sensor according to (31), the reference
electrode may be arranged between the counter electrode and the
working electrode.
[0081] (33) In the sensor according to (31) or (32), the outermost
surface of the reference electrode is covered with a carbon
including layer.
[0082] (34) The sensor according to any one of (31) to (33) may
further include: a coverlay that is provided on the insulating
substrate and has openings through which the electrodes of the
electrode group are exposed to the outside; and a carbon including
layer. The carbon including layer may be formed on the surface of
the coverlay surface and at least the surface of the electrode
disposed in the opening.
[0083] (35) In the sensor according to (34), each opening of the
coverlay may be formed such that the area thereof is more than that
of each electrode exposed through the opening.
[0084] (36) In the sensor according to (34) or (35), the opening of
the coverlay may be formed such that the diameter thereof is
increased from an upper surface to a lower surface.
[0085] (37) In the sensor according to any one of (34) to (36), the
coverlay may be made of a single material, and the coverlay may be
formed such that the area of the opening in the upper surface is
less than the area of the opening in the lower surface.
[0086] (38) In the sensor according to (34) or (35), the coverlay
may include at least two layers, that is, a coverlay film and an
adhesive layer. The edge of an opening in the adhesive layer and
the edge of an opening of the coverlay film may be arranged at the
same position, or the edge of the opening in the adhesive layer may
be arranged outside the edge of the opening of the coverlay
film.
[0087] (39) In the sensor according to any one of (31) to (35),
gold may be coated on at least a portion of the outermost surface
of the working electrode and/or the counter electrode.
[0088] (40) In the sensor according to (39), any one of a carbon
including layer, a nickel layer, and a palladium layer may be
provided as a base layer of the outermost layer.
[0089] (41) In the sensor according to any one of (34) to (40), an
organic monolayer may be formed on at least a portion of the
outermost surface of the working electrode and/or the counter
electrode.
[0090] (42) In the sensor according to (41), the organic monolayer
may have a substituent group including at least one selected from
the group consisting of chlorine, bromine, sulfur, nitrogen, and
oxygen on the surface thereof.
[0091] (43) In the sensor according to any one of (34) to (42), the
insulating substrate may be made of an organic material.
[0092] (44) A sensor system includes: the sensor according to any
one of (34) to (43); and a measuring device that measures
voltage-current characteristics between at least two electrodes
among the electrodes of the sensor.
[0093] (45) The sensor system according to (44) may further include
a connector and a wiring member that electrically connect the
sensor and the measuring device.
[0094] (46) The sensor system according to (45) may further
include: an analysis liquid container; and a pre-processing unit
that neutralizes or filters a liquid to be analyzed, or makes the
liquid to be analyzed hardly soluble.
[0095] (47) A portable sensor system includes: the sensor according
to any one of (35) to (44); a measuring device that measures
voltage-current characteristics between two electrodes among the
electrodes of the sensor; and a portable container that
accommodates at least the sensor and the measuring device.
[0096] (48) The portable sensor system according to (47) may
further include a connector and wiring lines that are accommodated
in the portable container and electrically connect the sensor and
the measuring device.
[0097] (49) A method of analyzing metal ions directly analyzes a
liquid to be analyzed using the sensor system according to any one
of (44) to (46), without performing a pre-process.
[0098] (50) A method of analyzing metal ions directly analyzes a
liquid to be analyzed using the sensor system according to (46),
with performing a pre-process.
[0099] (51) In the method of analyzing metal ions according to
(50), the liquid to be analyzed may be analyzed by a colorimetric
method after neutralization and filtering.
[0100] (52) In a method of analyzing metal ions using the sensor
system according to (46), the liquid to be analyzed may be analyzed
by an electrochemical method after neutralization and
filtering.
[0101] (53) In the method of analyzing metal ions using the sensor
system according to (46), the liquid to be analyzed may be analyzed
by an electrochemical method after being neutralized, made hardly
soluble, and filtered.
[0102] (54) A mounting substrate includes: an insulating substrate;
an electrode group that is provided on the insulating substrate; a
coverlay that has openings through which the electrode group is
exposed to the outside; and a carbon including layer. The carbon
including layer is disposed on the surface of the coverlay and in
the openings, and the carbon including layer on the surface of the
coverlay is separated from at least one electrode of the electrode
group at the edge of the opening.
[0103] (55) In the mounting substrate according to (54), the
opening of the coverlay may be formed such that the diameter
thereof is increased from an upper surface to a lower surface.
[0104] (56) In the mounting substrate according to (54), the
coverlay may be made of a single material, and the coverlay may be
formed such that the area of the opening in the upper surface is
less than the area of the opening in the lower surface.
[0105] (57) In the mounting substrate according to (54), the
coverlay may include at least two layers, that is, a coverlay film
and an adhesive layer. The edge of an opening in the adhesive layer
and the edge of an opening of the coverlay film may be arranged at
the same position, or the edge of the opening in the adhesive layer
may be arranged outside the edge of the opening of the coverlay
film.
[0106] (58) A method of analyzing a plating preventing chemical
species includes: contacting a copper plating solution that is used
for copper plating with at least a first electrode and a second
electrode; applying a voltage whose level varies over time between
the first and second electrodes; identifying the plating preventing
chemical species in a voltage range in which a variation in a
current flowing between the first and second electrodes is
observed; and analyzing the concentration of the plating preventing
chemical species based on the maximum value of the current or the
integral value of the current with respect to the voltage.
[0107] (59) A method of analyzing a compound produced from a copper
plating solution during copper plating includes: contacting the
copper plating solution that is used for the copper plating with at
least a first electrode and a second electrode; applying a voltage
whose level varies over time between the first and second
electrodes; identifying the compound produced from the copper
plating solution during the copper plating in a voltage range in
which a variation in a current flowing between the first and second
electrodes is observed; and analyzing the concentration of the
compound produced from the copper plating solution during the
copper plating based on the maximum value of the current or the
integral value of the current with respect to the voltage.
[0108] (60) The method of analyzing a plating preventing chemical
species according to (58) may further include: providing a third
electrode that supplies at least a portion of the potential thereof
to the first electrode or the second electrode at the same polarity
or different polarities; and contacting the copper plating solution
with the third electrode.
[0109] (61) The method of analyzing a compound produced from a
copper plating solution during copper plating according to (59) may
further include: providing a third electrode that supplies at least
a portion of the potential thereof to the first electrode or the
second electrode at the same polarity or different polarities; and
contacting the copper plating solution with the third
electrode.
[0110] (62) In the method of analyzing a plating preventing
chemical species according to (58) or (60), the voltage range may
be from +0.2 V to +2.0 V.
[0111] (63) In the method of analyzing a produced compound
according to (59) or (61), the voltage range may be from +0.2 V to
+2.0 V.
[0112] (64) In the method of analyzing a plating preventing
chemical species according to (58) or (60), the concentration of
the plating preventing chemical species may be analyzed based on a
value obtained by subtracting the maximum value of the current or
the integral value of the current with respect to the voltage,
which is obtained from an initial make-up bath copper plating
solution before being used, instead of the copper plating solution
that is being used, from the maximum value of the current or the
integral value of the current with respect to the voltage, which is
obtained from the copper plating solution that is used for the
copper plating.
[0113] (65) In the method of analyzing a produced compound
according to (59) or (61), the concentration of the produced
compound may be analyzed based on a value obtained by subtracting
the maximum value of the current or the integral value of the
current with respect to the voltage, which is obtained from an
initial make-up bath copper plating solution before being used,
instead of the copper plating solution that is being used, from the
maximum value of the current or the integral value of the current
with respect to the voltage, which is obtained from the copper
plating solution that is used for the copper plating.
[0114] (66) In the method of analyzing a plating preventing
chemical species according to (64), the temperature difference
between the initial make-up bath copper plating solution and the
copper plating solution that is being used may be within 10.degree.
C.
[0115] (67) In the method of analyzing a produced compound
according to (65), the temperature difference between the initial
make-up bath copper plating solution and the copper plating
solution that is being used may be within 10.degree. C.
[0116] (68) In the method of analyzing a plating preventing
chemical species according to (64), the temperature of the initial
make-up bath copper plating solution and the temperature of the
copper plating solution that is being used may be measured. The
rate of change of the maximum value of the current or the integral
value of the current with respect to the voltage of the initial
make-up bath copper plating solution, which is separately analyzed,
according to the temperature may be used to covert the maximum
value of the current or the integral value of the current with
respect to the voltage of the analyzed initial make-up bath copper
plating solution into a value corresponding to the temperature of
the copper plating solution that is being used. The concentration
of the plating preventing chemical species may be analyzed based on
a value obtained by subtracting the converted value from the
maximum value of the current or the integral value of the current
with respect to the voltage of the copper plating solution used for
copper plating.
[0117] (69) In the method of analyzing a produced compound
according to (65), the temperature of the initial make-up bath
copper plating solution and the temperature of the copper plating
solution that is being used may be measured. the rate of change of
the maximum value of the current or the integral value of the
current with respect to the voltage of the initial make-up bath
copper plating solution, which is separately analyzed, according to
the temperature may be used to covert the maximum value of the
current or the integral value of the current with respect to the
voltage of the analyzed initial make-up bath copper plating
solution into a value corresponding to the temperature of the
copper plating solution that is being used. The concentration of
the produced compound may be analyzed based on a value obtained by
subtracting the converted value from the maximum value of the
current or the integral value of the current with respect to the
voltage of the copper plating solution used for copper plating.
[0118] (70) In the method of analyzing a plating preventing
chemical species according to (58), (60), or (64), a copper plating
solution obtained by making an analysis preventing material, which
is included in the initial make-up bath copper plating solution or
the copper plating solution that is being used, hardly soluble may
be used.
[0119] (71) In the method of analyzing a produced compound
according to (59), (61), or (65), a copper plating solution
obtained by making an analysis preventing material, which is
included in the initial make-up bath copper plating solution or the
copper plating solution that is being used, hardly soluble may be
used.
[0120] (72) In the method of analyzing a plating preventing
chemical species according to (58), (60), or (64), a copper plating
solution obtained by making an analysis preventing material, which
is included in the initial make-up bath copper plating solution or
the copper plating solution that is being used, hardly soluble with
a chemical species which forms a hardly soluble compound with the
analysis preventing material may be used.
[0121] (73) In the method of analyzing a produced compound
according to (59), (61), or (65), a copper plating solution
obtained by making an analysis preventing material, which is
included in the initial make-up bath copper plating solution or the
copper plating solution that is being used, hardly soluble with a
chemical species which forms a hardly soluble compound with the
analysis preventing material may be used.
[0122] (74) In the method of analyzing a plating preventing
chemical species according to (58), (60), or (64), a copper plating
solution obtained by making an analysis preventing material, which
is included in the initial make-up bath copper plating solution or
the copper plating solution that is being used, hardly soluble with
cations which form a hardly soluble salt with the analysis
preventing material may be used.
[0123] (75) In the method of analyzing a produced compound
according to (59), (61), or (65), a copper plating solution
obtained by making an analysis preventing material, which is
included in the initial make-up bath copper plating solution or the
copper plating solution that is being used, hardly soluble with
cations which form a hardly soluble salt with the analysis
preventing material may be used.
[0124] (76) In the method of analyzing a plating preventing
chemical species according to (70), (72), or (74), silver ions,
monovalent mercury ions, or thallium ions may be added to make the
copper plating solution hardly soluble.
[0125] (77) In the method of analyzing a produced compound
according to (71), (73), or (75), silver ions, monovalent mercury
ions, or thallium ions may be added to make the copper plating
solution hardly soluble.
[0126] (78) In the method of analyzing a plating preventing
chemical species according to (58), (60), or (64), a plating
solution that is obtained in stages by making a plurality of
analysis preventing materials, which is included in the initial
make-up bath copper plating solution or the copper plating solution
that is being used, hardly soluble in stages may be used.
[0127] (79) In the method of analyzing a plating preventing
chemical species or a produced compound according to any one of
(70) to (77), after a pre-process selected from a precipitation
process and/or a filtering process is performed to make the
analysis preventing material, which is included in the initial
make-up bath copper plating solution or the copper plating solution
that is being used, hardly soluble, the analysis may be
performed.
[0128] (80) A method of analyzing a monovalent copper chemical
species in a mixture includes: contacting a mixture including the
monovalent copper chemical species, which is an analyze target, and
two or more kinds of chemical species other than the analyze target
and/or a mist thereof with a first electrode and a second
electrode; applying a voltage whose level varies in a range of 0.2
V to 2.0 V over time between the first and second electrodes;
identifying the monovalent copper chemical species in the mixture
in a voltage range in which the maximum value of a current flowing
between the first and second electrodes is observed; and analyzing
the concentration of the monovalent copper chemical species in the
mixture based on the maximum value of the current or the integral
value of the current with respect to the voltage.
[0129] (81) In the method of analyzing a monovalent copper chemical
species in a mixture according to (80), an analysis preventing
material included in the mixture may be made hardly soluble. The
voltage whose level varies in the range of 0.2 V to 2.0 V over time
may be applied between the first and second electrodes. The
monovalent copper chemical species in the mixture may be identified
in the voltage range in which the maximum value of the current
flowing between the first and second electrodes is observed. The
concentration of the monovalent copper chemical species in the
mixture may be analyzed based on the maximum value of the current
or the integral value of the current with respect to the
voltage.
[0130] (82) The method of analyzing a monovalent copper chemical
species in a mixture according to (80) or (81) may further include:
providing a third electrode that supplies at least a portion of the
potential thereof to the first electrode or the second electrode at
the same polarity or different polarities; and contacting the
mixture with the third electrode.
[0131] (83) In the method of analyzing a monovalent copper chemical
species in a mixture according to any one of (80) to (82), the
concentration of the monovalent copper chemical species in the
mixture may be analyzed based on a value obtained by subtracting
the maximum value of the current or the integral value of the
current, which is obtained from a reference solution instead of the
mixture, from the maximum value of the current or the integral
value of the current with respect to the voltage, which is obtained
from the mixture.
[0132] (84) In the method of analyzing a monovalent copper chemical
species in a mixture according to (83), the temperature difference
between the reference solution and the mixture may be within
10.degree. C.
[0133] (85) In the method of analyzing a monovalent copper chemical
species in a mixture according to (83), the temperature of the
reference solution and the temperature of the mixture may be
measured. The rate of change of the maximum value of the current or
the integral value of the current with respect to the voltage of
the reference solution, which is separately analyzed, according to
the temperature may be used to covert the maximum value of the
current or the integral value of the current of the analyzed
reference solution into a value corresponding to the temperature of
the mixture. The concentration of the monovalent copper chemical
species may be analyzed based on a value obtained by subtracting
the converted value from the maximum value of the current or the
integral value of the current of the mixture.
[0134] (86) In the method of analyzing a monovalent copper chemical
species in a mixture according to any one of (80) to (83), a
mixture obtained by making an analysis preventing material included
in the reference solution or the mixture hardly soluble with a
chemical species which form a hardly soluble compound with the
analysis preventing material may be used.
[0135] (87) In the method of analyzing a monovalent copper chemical
species in a mixture according to any one of (80) to (83), a
mixture obtained by making an analysis preventing material included
in the reference solution or the mixture hardly soluble with
cations which form a hardly soluble salt with the analysis
preventing material may be used.
[0136] (88) In the method of analyzing a monovalent copper chemical
species in a mixture according to (86) or (87), silver ions,
monovalent mercury ions, or thallium ions may be added to make the
solution hardly soluble.
[0137] (89) In the method of analyzing a monovalent copper chemical
species in a mixture according to any one of (80) to (83), after a
pre-process selected from a precipitation process and/or a
filtering process for filtering a precipitate by the precipitation
is performed to make the analysis preventing material included in
the reference solution or the mixture hardly soluble, the analysis
may be performed.
[0138] In the invention, the term "analysis" used in the
description of the invention means qualitatively determining
whether there is a chemical species that the operator wants to know
and/or quantitatively determining an increase in the concentration
of a chemical species that the operator wants to know.
Effects of the Invention
[0139] According to the sensor of the invention, when the wiring
line is insulated, the function of the electrode is separated from
the function the wiring line. As a result, the area of the
electrode is constant regardless of the depth or angle of the
sensor immersed in a liquid, mist, or gas, which is an analyze
target. Therefore, the reproducibility of quantitative analysis is
improved.
[0140] In addition, it is possible to provide an inexpensive sensor
by forming an organic insulating portion.
[0141] When the organic substrate is used, it is possible to
achieve both the design reproducibility of the area of the
electrode and the insulation between the wiring lines with a
single-layer organic member, such as an organic coverlay, by the
insulation of a wiring line portion by the organic coverlay and the
designability of an effective electrode area by the definition of
the area of the opening.
[0142] The sensor system according to the invention includes the
above-mentioned sensor. Therefore, it is possible to integrally and
continuously perform a pre-process with high efficiency.
[0143] According to the sensor of another aspect of the invention,
since a wiring structure is insulated and coated by an organic
material, it is possible to obtain a flexible sensor. The
insulation between the wiring lines is maintained to be uniform
along the wiring lines, and it is possible to ensure measures for
preventing the leakage of a current. In the formation of the
electrode, the organic material is coated on the cross section of a
conductive line, and is removed by a laser such that the electrode
is exposed. Therefore, it is possible to flexibly correspond to
low-volume production and mass production. This structure can be
applied to the existing wire product and cable, and it is possible
to improve flexibility in the design of the system.
[0144] According to the sensor of still another aspect of the
invention, an insulating substrate for a sensor does not require
chemical resistance and heat resistance. In particular, it is
possible to provide a sensor with an electrode structure that does
not require an alignment and masking process for ensuring the
insulating property between the electrodes when a carbon including
layer is formed. Specifically, as a process for manufacturing the
substrate for a sensor, it is possible to select a multi-layer
forming process including all kinds of organic materials including
an organic material with heat resistance capable of corresponding
to a vacuum process and/or chemical resistance and an inorganic
material that cannot correspond to these characteristics. In
addition, an alignment and masking process for ensuring the
insulating property between the electrodes when a carbon including
layer is formed is not needed. Therefore, it is possible to
manufacture a substrate with high accuracy and high efficiency. The
carbon including layer can prevent the contamination of the
substrate and makes it possible to obtain an organic substrate
having resistance to the formation of a minute electrode by vacuum
film formation, which is required in the analysis of a complex
system.
[0145] The carbon including layer covering the surface of the
reference electrode stabilizes a base current and the potential of
the reference electrode. The carbon including layer covering the
working electrode makes it possible to form a metal layer made of a
single component or a composite component with a uniform area
using, for example, a vapor deposition method, a sputtering method,
a printing method, or an ink jet method. The uniform area is
achieved by preventing a variation in the area of the electrode due
to the infiltration of an analyte into the interface between the
electrode and an insulating material. In this way, it is possible
to manufacture an electrode with sufficient durability to
repeatedly perform measurement on the same substrate.
[0146] In the analysis of a complex system, a plurality of working
electrodes having an organic monolayer formed thereon is formed
while changing their areas. Then, multi-point analysis is performed
to analyze a variation in the obtained potential or the time
required to reach a specific potential. Therefore, it is possible
to analyze concentration within a wide range. In particular, when
minute electrodes are formed and it is necessary to analyze a very
small amount of material, it is necessary to form a substrate
capable of corresponding to a vacuum film forming method, such as
gold vapor deposition or sputtering. Since this organic substrate
has a carbon including layer with heat resistance formed thereon,
it is possible to perform gold vapor deposition or sputtering, and
gives a means for introducing a vacuum film forming method that has
not been available in the organic substrate. In the vacuum film
forming method, since the carbon including layer is formed on a
base, the surface roughness of the wiring line and the electrode on
the organic substrate is reduced, and it is possible to activate
the induction of the surface potential of the organic
monolayer.
[0147] The sensor system according to the invention includes the
above-mentioned sensor. Therefore, it is possible to provide a
sensor system capable of integrally and continuously performing a
pre-process with high efficiency.
[0148] The portable sensor system according to the invention
includes the above-mentioned sensor. Therefore, it is possible to
provide a portable sensor system that can be carried to a desired
place and easily analyze a very small amount of analyte in a short
time on the spot.
[0149] According to the method of analyzing metal ions according to
the invention, it is possible to analyze a monovalent copper
chemical species from a complex system included in an analysis
preventing material or a plurality of metal ions relatively easily
and with high reproducibility. In the analysis of a complex system,
that is, in high-accuracy analysis, the invention has an effect of
simplifying a complicated pre-process. That is, it is possible to
omit a complicated pre-process indispensable to the analysis of a
complex system, that is, high-accuracy analysis. In addition,
particularly, in the analysis of monovalent copper, it is possible
to provide a method of qualitatively and quantitatively analyzing
metal ions using a combination of an electrochemical method and a
colorimetric method.
[0150] The mounting substrate according to the invention has a
structure in which the electrode and the carbon including layer of
the coverlay surface that need to be insulated from each other when
the carbon including layer is formed on the electrode in the same
process are separated from each other by the recession structure of
the coverlay and the surface of the coverlay surface is coated. It
is possible to form electrodes capable of improving the
characteristics of a sliding portion for connection to a connector
and the characteristics of semiconductor chip mounting according to
the related art, such as gold wire bonding. That is, it is possible
to significantly reduce a load applied to the cleaning management
of gold electrodes which are contaminated with a plating solution.
A black carbon including layer coated on the surface of the
coverlay can prevent the generation of a small amount of current
induced by the extending wiring line due to optical reaction. In
the mounting substrate to which a high-speed switching signal is
applied, the carbon including layer can attenuate switching noise.
Therefore, it is possible to ensure a noise margin.
[0151] According to the method of analyzing a plating preventing
material or the method of analyzing a produced compound according
to the invention, it is possible to analyze a plating preventing
chemical species included in a plating solution having an analysis
preventing material or a large amount of bivalent copper, and a
compound produced when a plating solution is used relatively easily
and with high reproducibility.
[0152] The method of analyzing a monovalent copper chemical species
according to the invention can be used to analyze other metal ions.
For example, the method can analyze soil in an environment and ions
related to a medical and health field, in addition to an industrial
chemical group such as a plating solution.
BRIEF DESCRIPTION OF THE DRAWINGS
[0153] FIG. 1 is a diagram illustrating the wiring pattern of a
substrate of a metal ion sensor according to the invention.
[0154] FIG. 2 is a diagram illustrating the surface mounting
pattern of a connector fitted to the metal ion sensor according to
the invention.
[0155] FIG. 3 is a diagram illustrating the hole pattern (opening
pattern) of a coverlay.
[0156] FIG. 4 is a diagram illustrating an observed cross section
(before coverlay is covered) taken along the line A-A of FIG.
1.
[0157] FIG. 5 is a cross-sectional view illustrating a substrate
covered with the coverlay shown in FIG. 3.
[0158] FIG. 6 is an enlarged view illustrating the vicinity of a
left opening in FIG. 5 and shows the infiltration state of an
adhesive from the coverlay.
[0159] FIG. 7 is a cross-sectional view when a wiring line is
transferred into the substrate.
[0160] FIG. 8 is a cross-sectional view illustrating the state
where an etchback process is performed on the covered coverlay.
[0161] FIG. 9 is a cross-sectional view illustrating the state
where a carbon including layer is formed after the etchback
process.
[0162] FIG. 10 is a cross-sectional view illustrating the state
where only an electrode is exposed from the surface and an
extending wiring line is formed in the substrate.
[0163] FIG. 11 is a cross-sectional view illustrating the state
where the electrode and the extending wiring line are transferred
(buried) into the substrate.
[0164] FIG. 12 is a cross-sectional view illustrating the case in
which the surface of a conductor for buried connection directly
serves as an electrode.
[0165] FIG. 13 is a diagram illustrating a structure in which the
surface of the conductor for buried connection is arranged at least
on a connector connection portion other than the outermost direct
measuring electrode.
[0166] FIG. 14 is a diagram illustrating a structure in which the
surfaces of connection conductors of a substrate for connection
used to arrange a transfer wiring line on the connector connection
portion other than a measuring electrode face each other.
[0167] FIG. 15 is a diagram schematically illustrating a method of
extracting monovalent copper ions by making copper sulfide hardly
soluble with sodium sulfide after a neutralizing process with
sodium hydroxide is performed.
[0168] FIG. 16 is a diagram schematically illustrating a method of
making copper hydroxide hardly soluble with excess sodium
hydroxide.
[0169] FIG. 17 is a perspective view illustrating a twin-peak kit
for effectively performing a pre-process.
[0170] FIG. 18 is a perspective view illustrating the twin-peak kit
including a temperature-controlled tank.
[0171] FIG. 19 is a diagram illustrating a colorimetric technique
for analyzing monovalent copper ions.
[0172] FIG. 20 is a diagram illustrating a method using cyclic
voltammetry.
[0173] FIG. 21 is a graph illustrating data obtained by analyzing
whether there is monovalent copper using the method shown in FIG.
20.
[0174] FIG. 22 is a graph illustrating the analysis result when a
silver/silver chloride electrode used in electrochemistry is used
as a reference electrode, Pt is used as a counter electrode, and
gold is used as a working electrode.
[0175] FIG. 23 is a graph illustrating the analysis result when
tough carbon is used as the reference electrode, tough carbon is
used as the counter electrode, and gold is used as the working
electrode.
[0176] FIG. 24 is a graph illustrating the analysis result when
tough carbon is used as the reference electrode, tough carbon is
used as the counter electrode, and gold is used as the working
electrode, which is different from the graph shown in FIG. 23.
[0177] FIG. 25 is a graph illustrating a variation in surface
potential before and after analysis.
[0178] FIG. 26 is a graph illustrating the analysis result of a
copper plating solution when the metal ion sensor according to the
invention is used.
[0179] FIG. 27 is a graph illustrating the analysis result of a
copper plating solution when the metal ion sensor according to the
invention is used and a filtering process is not performed.
[0180] FIG. 28 is a graph illustrating the analysis result of a
copper plating solution when a metal ion sensor according to
another embodiment of the invention is used and a filtering process
is not performed.
[0181] FIG. 29 is a graph illustrating the analysis result of a
copper plating solution when a metal ion sensor according to
another embodiment of the invention is used and a filtering process
is not performed.
[0182] FIG. 30 is a diagram schematically illustrating the state
where the sensor according to the invention and the sensor
according to the related art are immersed in a copper plating
solution and analysis is performed while changing the depth D of
immersion.
[0183] FIG. 31 is a graph illustrating the measurement result of
the maximum value of a current, which is a CV signal for the depth
D of immersion, when the sensors shown in FIG. 30 are used to
perform analysis while changing the depth of immersion.
[0184] FIG. 32 is a diagram schematically illustrating the state
where the sensor according to the invention and the sensor
according to the related art are immersed in a copper plating
solution and analysis is performed while changing the angle 0 of
immersion.
[0185] FIG. 33 is a graph illustrating the measurement result of
the maximum value of a current, which is a CV signal for the angle
0 of immersion, when the sensors shown in FIG. 30 are used to
perform analysis while changing the angle of immersion.
[0186] FIG. 34 is a top view illustrating a sensor substrate used
in Example 14.
[0187] FIG. 35 is a diagram schematically illustrating the cross
section of the sensor substrate shown in Example 14.
[0188] FIG. 36 is a top view illustrating a coverlay adhered to the
sensor substrate shown in FIG. 34.
[0189] FIG. 37 is a graph illustrating the analysis result of a
filled copper plating solution by six sensors according to Example
14.
[0190] FIG. 38 is a graph illustrating the analysis result of an
initial make-up bath solution by six sensors according to Example
14.
[0191] FIG. 39 is a graph illustrating the analysis result of a
filled copper plating solution by ten sensors without the structure
according to the invention.
[0192] FIG. 40 is a diagram illustrating an analysis sequence
according to the invention.
[0193] FIG. 41 is a perspective view illustrating an example of a
portable sensor system according to the invention.
[0194] FIG. 42 is a graph illustrating a variation in the
temperature of an analyte over time when the twin-peak kit shown in
FIG. 18 is used to cool the analyte contained in a cylinder with
cold water and when the analyte contained in the cylinder is not
cooled.
EXPLANATION OF REFERENCE NUMERALS
[0195] 10: Metal ion sensor [0196] 12: Insulating substrate [0197]
14: Extending wiring line [0198] 15: Conductor for buried
connection [0199] 16: Measuring terminal (group) [0200] 18:
Electrode [0201] 20: Connector mounting terminal unit [0202] 22:
Terminal unit [0203] 24: Extending wiring line [0204] 30: Coverlay
[0205] 30A: Coverlay film [0206] 30B: Adhesive layer [0207] 32:
Opening [0208] 40: Insulating substrate [0209] 42: Reinforcing
member (polyimide) [0210] 44: Adhesive [0211] 46: Base material
[0212] 50: Carbon including layer [0213] 60: Twin-peak kit [0214]
62: Analysis liquid container (cylinder) [0215] 64: Analysis liquid
container (cylinder) [0216] 65: Air hole [0217] 66: Filter [0218]
68: Piston [0219] 70: Piston [0220] 80: Reference electrode [0221]
82: Counter electrode [0222] 84: Working electrode [0223] 90, 92:
Analysis liquid container [0224] 94: Temperature control layer
[0225] C1, C2, C3, C4, C5: Counter [0226] R1, R2, R3, R4, R5:
Reference electrode [0227] W1, W2, W3, W4, W5: Working
electrode
BEST MODE FOR CARRYING OUT THE INVENTION
[0228] A sensor according to the invention includes: first and
second conductive electrodes; first and second conductive wiring
lines that are respectively connected to the first and second
conductive electrodes; and an insulating portion that insulates the
first wiring line from the second wiring line and insulates the
first and second wiring lines from a liquid, mist, or gas including
an analyte. The insulating portion is made of an organic material,
and at least the surfaces of portions of the first and second
electrodes that come into contact with the liquid, the mist, or the
gas including the analyte are made of a material that is insoluble
by the liquid or the mist including the analyte or a material that
is not eroded by the gas including the analyte.
[0229] The simplest structure of a metal ion sensor (in some cases,
simply referred to as an ion sensor) to which the sensor according
to the invention is applied includes at least first and second
electrodes and first and second connection wiring lines that are
electrically connected to the first and second electrodes and are
covered with an insulating portion made of an organic material. In
this embodiment, the ion sensor further includes a third electrode
that is supplied at the same polarity or a different polarities and
a third connection wiring line that is electrically connected to
the third electrode and is covered with an organic insulating
portion, which will be described in detail below. The surface of at
least a portion of the third electrode that comes into contact with
a liquid, mist, or gas including an analyte is made of a material
that is not soluble by the liquid or mist including the analyte, or
a material that is not corroded by the analyte. Some examples of
sensors are disclosed together with examples of an analysis method
according to the invention. However, combinations of the analysis
methods and the sensors disclosed therein are not fixed, but the
analysis methods according to examples may be implemented using
other sensors.
[0230] The ion sensor, which will be described in detail below,
includes a insulating substrate, an electrode group including
first, second, and third electrodes that are arranged on the same
surface of the insulating substrate, a connection wiring line group
that includes one or more layers and is electrically connected to
the electrode group, and a connection terminal or measuring
terminal group that is electrically connected to the connection
wiring line group. Actually, in many cases, the first and second
electrodes are called a working electrode and a counter electrode,
and the third electrode is called a reference electrode.
[0231] Specifically, a coverlay having openings formed therein
through which each of the electrode groups is exposed to the
outside is provided on the insulating substrate, and a carbon
including layer is formed at least on the surface of the coverlay
and the surface of the electrode disposed in the opening. The
structure before the carbon including layer is formed is also
included in the embodiment of the invention, and a portion of the
connection wiring line surrounded by an organic coverlay and an
organic insulating substrate is an insulating portion of the
connection wiring line made of an organic material.
[0232] The above-mentioned aspect will be described below.
[0233] As described above, the organic insulating material used in
the sensor according to the invention is not particularly limited.
For example, organic materials, such as polyimide, epoxy, and
liquid crystal polymer, may be used. In particular, among the
above-mentioned materials, it is preferable to use the liquid
crystal polymer or Teflon (registered trademark) as the organic
insulating material.
[0234] As the wiring material used in the sensor according to the
invention, any of the following materials may be used: an
electrolytic copper foil; a rolled copper foil; a thin copper film;
materials obtained by coating the foils and the film with gold
using plating, sputtering, or vapor deposition; a copper line; a
gold line; a silver line; a platinum line; and an alloy line of
platinum and iridium. For example, subtractive, additive, and
wiring line transfer methods may be applied to the wiring
substrate. For example, a semi-hardened and/or hardened
thermosetting resin, a photo-curable resin, or a thermoplastic
resin may be used as the insulating material.
[0235] As the thermosetting resin, any of the following materials
may be used: at least one selected from an epoxy resin; a
bismaleimide triazine resin, a polyimide resin, a cyanoacrylate
resin, a phenolic resin, an unsaturated polyester resin, a melamine
resin, a urea resin, a polyisocyanate resin, a furan resin, a
resorcinol resin, a xylene resin, a benzoguanamine resin, a diallyl
phthalate resin, a silicon modified epoxy resin, a silicon modified
polyamideimide resin, and a benzocyclobutene resin; and materials
obtained by heating mixtures of the resins and a hardener or a
hardening accelerator and hardening or partially hardening the
mixtures, if necessary.
[0236] As the photo-curable resin, any of the following materials
may be used: at least one selected from an unsaturated polyester
resin, a polyester acrylate resin, a urethaneacrylate resin, a
silicon acrylate resin, and an epoxy acrylate resin; and materials
obtained by exposing or heating mixtures of the resins and a photo
initiator, a hardener, or a hardening accelerator and hardening or
partially hardening the mixture, if necessary.
[0237] As the thermoplastic resin, any of the following materials
may be used: at least one selected from a polycarbonate resin, a
polysulfone resin, a polyetherimide resin, a thermoplastic
polyimide resin, a polytetrafluoroethylene resin, a
polyhexafluoropropylene resin, a polyether ether ketone resin, a
vinyl chloride resin, a polyethylene resin, a polyamideimide resin,
a polyphenylene sulfide resin, a polyoxybenzoate resin, and a
liquid crystal polymer; materials obtained by heating mixtures of
the resins and a hardener or a hardening accelerator and hardening
or partially hardening the mixtures, if necessary.
[0238] The insulating resin may be a insulating resin composition,
which is a mixture of different kinds of resins, and the insulating
resin composition may include an inorganic filler, such as a silica
or a metal oxide, as a filler. The inorganic filler may be
conductive particles, such as nickel, gold, or silver particles, or
resin particles plated with these metal materials. In addition,
materials impregnated with the nonwoven fabric or woven fabric of
glass fiber may be used as the inorganic filler.
[0239] Next, the structure of the electrode of the sensor according
to the invention will be described with reference to the drawings.
The invention is not limited to the following embodiments. Various
modifications and other aspects of the invention can be made within
the scope and spirit of the invention.
[0240] FIG. 1 is a diagram illustrating a metal ion sensor 10
according to the invention, and shows the basic wiring pattern of a
throwaway substrate. In FIG. 1, C, R, and W denote a counter
electrode, a reference electrode, and a working electrode
(corresponding to examples of a second electrode, a third
electrode, and a first electrode), respectively. Suffixes 1 to 5 of
the characters C, R, and W indicate set numbers of C, R, and W, and
correspond to examples of the structures of the electrodes used to
measure current-voltage characteristics or voltages. They form one
electrode group. In FIG. 1, five electrode groups are arranged, and
each electrode may have any shape, such as a circular shape or a
rectangular shape. An extending wiring line (wiring member) 14
extends from each electrode to a measuring terminal (connection
terminal) 16 that is fitted and connected to a connector provided
at the edge of the substrate. In general, the wiring line connected
to the electrode has a tapered shape in order to reduce stress and
prevent the cutting of the wiring line. In addition, the extending
wiring line 14 passes through the electrodes. In a substrate with a
predetermined size, when the number of electrodes increases or the
pitch between the electrodes is reduced, it is necessary to
increase the number of wiring lines passing through the electrodes.
As a result, it is necessary to reduce the width of the wiring line
and the gap between the wiring lines. Therefore, it is very
important to ensure insulating property between the extending
wiring lines. For example, the wiring line may be formed by forming
a direct gold plating layer after copper etching.
[0241] The reference electrode, the working electrode, and the
counter electrode may be arranged such that the working electrode
is separated from the counter electrode with the reference
electrode interposed therebetween. This arrangement makes it
possible to increase a current value, which contributes to
increasing sensitivity. For example, in FIG. 36, an example in
which R3, C3, and C2 are used as the reference electrode, the
counter electrode, and the working electrode corresponds to this
arrangement.
[0242] FIG. 2 is a diagram illustrating a pattern for mounting
connectors on the surface of the fitted substrate used in a sensor
unit. Reference numeral 20 denotes a connector mounting terminal
unit (connection terminal), reference numeral 22 denotes a terminal
unit for mounting wiring lines and members connected to a measuring
device, and reference numeral 24 denotes an extending wiring line
that extends from the connector mounting terminal unit 20 to the
terminal unit 22. In FIG. 2, the connector mounting terminal unit
20 that is not used is represented by a white rectangular, and only
one extending wiring line is denoted by reference numeral 24.
However, the extending wiring lines 24 connect the connector
mounting unit 20 and the terminal unit 22. As such, it will be
easily understood that, when the number of electrodes is increased,
the substrate on which the connectors are mounted needs to have a
multi-layer structure; otherwise, it is very difficult to perform
multi-point analysis.
[0243] FIG. 4 is a cross-sectional view taken along the line A-A of
FIG. 1. It is preferable that a direct gold plating layer be formed
on the surfaces of the wiring lines after copper etching. After the
direct gold plating layer is formed, the surfaces of the wiring
lines are covered with a coverlay 30 shown in FIG. 3 such that only
electrode portions, the peripheral portions thereof, and terminal
portions that are fitted and connected to the connectors are
exposed. The coverlay 30 includes openings 32 which correspond to
each electrode and through which the electrode groups are exposed
to the outside. In FIG. 3, in the coverlay 30, each opening 32 is
provided above the electrode which is exposed to the outside
through the opening 32 and the area of each opening is slightly
more than that of the electrode (the opening has a clearance that
is 200 .mu.m more than that of the electrode and has a diameter
that is 400 .mu.m more than that of the electrode). The clearance
is also called a creeping distance. This correlation is suitable to
cover all the electrodes with a carbon including layer, which will
be described below.
[0244] However, in this case, since a portion of the wiring line
connected to the electrode is not covered with the coverlay, there
is a concern that the portion will serve as an electrode.
Therefore, in order to strictly define the area of the electrode,
the edge of the opening 32 is disposed inside the electrode.
[0245] In the invention, the coverlay is made of an insulating
organic material. However, the coverlay may be made of a single
material or it may include a coverlay film and an adhesive layer.
When the coverlay is made of a single material, it is preferable
that a liquid crystal polymer be used as the single material.
[0246] When the coverlay includes the coverlay film and the
adhesive layer, for example, a polyimide film or a liquid crystal
polymer may be used as the coverlay film. Specifically, for
example, CISV1215 manufactured by NIKKAN INDUSTRIES CO., LTD., or
STABIAX or BAIC-C manufactured by JAPAN GORE-TEX INC. may be
used.
[0247] As the resin used for the adhesive layer, any of the
following materials may be used: an acrylic-resin-based adhesive,
an epoxy-resin-based adhesive, and a liquid crystal polymer. It is
preferable to use the liquid crystal polymer.
[0248] It is preferable that the thickness of the coverlay be
matched with the thickness of the connector. For example, when the
thickness of a base material fitted to the connector is 200
.mu.m.+-.30 .mu.m, it is preferable that the thickness of the
coverlay be in the range of 100 .mu.m to 200 .mu.m. When the
thickness of the base material fitted to the connector is 300
.mu.m.+-.30 .mu.m, it is preferable that the thickness of the
coverlay be in the range of 150 .mu.m to 300 .mu.m.
[0249] As such, the electrode is covered with the coverlay in order
to protect the extending wiring lines and prevent a current leakage
between the wiring lines due to immersion during analysis. FIG. 5
is a cross-sectional view illustrating an insulating substrate 40
and the coverlay 30 that covers the surface of the insulating
substrate 40 on which, for example, electrodes are formed. In this
case, the coverlay may be adhered to the insulating substrate with
an iron without applying a relatively large load. However, since
the extending wiring line 14 is exposed in a convex shape from the
surface, it is necessary to fill the gap between the wiring lines
with the coverlay 30. Therefore, it is preferable to apply
predetermined pressure at a predetermined temperature for a
predetermined time. However, in the manufacturing process, the
adhesive layer of the coverlay is infiltrated. FIG. 6 is an
enlarged view illustrating the left side of the opening shown in
FIG. 5 and shows the infiltration of the adhesive layer. The
infiltration of the adhesive layer is likely to contaminate the
surface of the electrode, which may result in a reduction in
yield.
[0250] As shown in FIG. 4, an adhesive 44 is adhered to a
reinforcing member 42. In this case, when there is a very small
amount of air at the interface therebetween, the air is expanded
when the coverlay 30 is adhered, and the reinforcing member 42
peels off, which causes a reduction in yield. It is preferable to
increase the clearance in order to prevent the contamination of the
surface of the electrode due to the infiltration of the adhesive.
Preferably, as shown in FIG. 7, when the wiring line is transferred
into the insulating substrate 40, it is not necessary to increase
the pressure or temperature required to fill up the gap between the
wiring lines, as compared to adhesion conditions to a flat surface,
and it is possible to significantly reduce the amount of adhesive
that is infiltrated. Alternatively, an adhesive 30B adhered to a
coverlay film 30A may be dried in advance and then adhered to the
insulating substrate. In this way, it is possible to reduce the
amount of flow of the adhesive.
[0251] It is preferable to transfer the wiring lines into the
insulating substrate 40 in order to prevent the reinforcing member
42 from peeling off. In this case, it is not necessary to apply the
pressure or temperature required to fill up the gap between the
wiring lines with the coverlay 30. As a result, it is possible to
prevent the expansion of air causing the peeling-off of the
reinforcing member.
[0252] In addition, it is preferable to selectively remove and
recess (etchback) the adhesive layer 30B of the coverlay 30 from
the edge of the opening by a predetermined amount in order to
prevent the infiltration of the adhesive. That is, it is preferable
to dispose the edge of the opening of the adhesive layer 30B
outside the edge of the opening of the coverlay film 30A, which is
shown in FIG. 8. Alternatively, the opening of the coverlay may be
formed such that the diameter thereof is increased from the upper
surface to the lower surface. When the coverlay is made of a single
material, the opening of the coverlay may be formed such that the
area of the opening in the upper surface is less than that of the
opening in the lower surface.
[0253] An etchback process may be performed in the following
order.
[0254] For example, when the thickness of the adhesive layer is 15
.mu.m, it is necessary to etchback the adhesive layer by a width of
at least 15 .mu.m from the edge of the opening in order to ensure a
sufficient insulating property. An example of an optimal process
method corresponding to the structure is described below.
[0255] (1) A substrate is cleaned with water. (2) The substrate is
immersed in DMF (for 5 minutes) according to the amount of
infiltration before the subsequent process. (3) The substrate is
immersed in a solution including 30 to 60 g/L of potassium
permanganate and 20 to 40 g/L of sodium hydroxide at a room
temperature to 90.degree. C., preferably, 60.degree. C. for 5
minutes to 60 minutes, preferably, 20 minutes. (4) The substrate is
cleaned with water. (5) Since the solution in the process (3) is an
alkali solution, the substrate is immersed in 0.3 N (8 ml/L) of
sulfuric acid for 5 minutes for neutralization. (6) The substrate
is tracked out (cleaning with water). (7) The substrate is cleaned
with water. (8) The substrate is dried at 100.degree. C. for 5
minutes.
[0256] As described above, the adhesive layer may be removed and
recessed by chemicals or an adhesive surface may be processed by a
router in advance. In addition, as a mechanical method that does
not perform removing and reccess with chemicals, preferably, the
following method is effective in which two coverlays are prepared
and openings are formed such that the diameter of an opening in the
upper coverlay is more than that of the opening in the lower
coverlay.
[0257] When the coverlay includes a cover film and an adhesive
layer, preferably, a liquid crystal polymer film BIAC-C
manufactured by JAPAN GORE-TEX INC. is used as the cover film, and
KS-7003 or KS-6600-7F with low flowability manufactured by HITACHI
CHEMICAL CO., LTD. may be used as the adhesive layer.
[0258] As a result of an intensive consideration by the inventors,
in the above-mentioned structure, when a carbon including layer was
formed on the surface of the substrate having the coverlay formed
thereon, it was possible to ensure insulating property between a
plurality of opening electrode portions. That is, this is because
an etchbacked portion insulates the carbon including layer formed
on the coverlay surface from an electrode surface layer formed on
the surface of the electrode.
[0259] It is preferable to use a vapor deposition method in order
to form the carbon including layer. Preferably, a carbon vapor
deposition method (see Japanese Patent No. 3660866), which is a
tough carbon method using an ion cluster beam capable of forming a
film at a temperature of 100.degree. C. or less, is used as the
vapor deposition method. The thickness of the carbon including
layer is as large as possible. However, the thickness of the carbon
including layer is preferably in the range of 0.1 .mu.m to 1 .mu.m,
more preferably, equal to or more than 0.3 Jim, in terms of
manufacturing costs. If the thickness of the carbon including layer
is equal to or more than 0.1 .mu.m, a base material (for example,
copper or gold) forming the wiring line is hardly affected
electrochemically, and the reference electrode is stabilized.
Therefore, the above-mentioned thickness range is most suitable to
reduce the size of the reference electrode.
[0260] It is preferable to apply a print paste using an ink jet
method in order to effectively produce the sensor. For example, the
technique and paste disclosed in JP-A Nos. 2006-147202,
2007-165708, and 2007-165709 may be applied as the print paste.
Specifically, carbon paste manufactured by HITACHI CHEMICAL CO.,
LTD. may be preferably used. In addition, as a printing method, an
application method using a syringe may be used. The hardening
temperature is in the range of 160.degree. C. to 210.degree. C. and
may be appropriately set depending on the heat resistance of a base
material.
[0261] In an immersion method using an alternate stacking method or
a printing method with carbon paste, the carbon including layer may
be formed in an etchback structure. Therefore, when an atmospheric
plasma apparatus manufactured by SEKISUI CHEMICAL CO., LTD or a
plasma processing apparatus is used to abrade the surface using a
plasma process with oxygen and/or argon, and a mixture of oxygen
and argon to make a hydrophilic surface and the carbon including
layer is formed on the surface, the carbon including layer is not
formed in an etchback portion, and insulating property between the
carbon including layer formed on the surface of the coverlay and
the electrode surface layer formed on the surface of the electrode
is ensured. In this case, it is preferable to perform a hydrophobic
treatment before the surface is abraded. For example, HMDS
(hexamethyldisilazane) or a coating agent including fluorine may be
used in the hydrophobic treatment.
[0262] FIG. 9 shows the state where a carbon including layer 50 is
covered in this way. In FIG. 9, the carbon including layer 50 is
formed on the entire surface of the coverlay 30 and is formed on
the surface of the electrode C5 and the surface of the insulating
substrate 40 in the opening. As shown in FIG. 9, when there is a
clearance between the opening of the coverlay 30 and the edge of
the electrode C5, the carbon including layer 50 is formed on the
surface of the insulating substrate 40. On the other hand, when
there is no clearance therebetween, the carbon including layer 50
is not formed on the surface of the insulating substrate 40. That
is, the carbon including layer 50 is formed at least on the surface
of the electrode in the opening of the coverlay 30.
[0263] It is preferable that gold be coated on at least a portion
of the outermost surface of at least one of the first electrode,
the second electrode, and the third electrode, specifically, the
working electrode and/or the counter electrode. This is for the
following reasons. That is, when etchback is performed, a tapered
portion of the extending wiring line connected to the electrode
portion or an exposed portion of the extending wiring line is
formed. When the coverlay is coated and a substrate is formed by
gold plating, a copper wiring line is exposed. This may cause a
change in copper ions during analysis and the cutting of the wiring
line during analysis. Therefore, it is preferable to perform gold
plating before the coverlay is coated. It is preferable to perform
direct gold plating as the gold plating. It is more preferable to
perform nickel/gold plating as the gold plating, and it is most
preferable to perform nickel/palladium/gold plating as the gold
plating. In this case, it is possible to prevent the production of
an alloy due to the mutual diffusion of gold and copper and the
formation of an oxide film on the surface electrode. Therefore, it
is possible to maintain the surface of a gold electrode in a stable
pure gold state. According to the invention, after a copper wiring
line is formed, a carbon film may be formed on the copper pattern
before the coverlay is coated or the copper pattern in an exposed
portion of the electrode after the coverlay is coated. In the
invention, a carbon including layer may be provided on the surface
of the copper wiring line plated with gold, and a pure gold
electrode may be provided on the carbon including layer by gold
vapor deposition, considering the case in which the extending
wiring line is disposed on the same surface as the electrode
surface. However, in this case, the exposure of a gold-plated
portion that is not covered with the carbon including layer is
likely to prevent analysis. Therefore, as shown in FIG. 10, it is
preferable that only the surface of an electrode 18 be exposed and
at least the extending wiring line 14 be formed inside the
insulating substrate 40. When the extending wiring line 14 is
formed so as to extend from the surface to an inner layer and is
then drawn to a surface layer, the structure in which the surface
wiring line and the electrode are transferred into the insulating
substrate 40 is effective in preventing the infiltration of the
adhesive layer 30B in the clearance portion and the prevention of a
current leakage between the extending wiring lines. Therefore, the
cross-sectional structure shown in FIG. 11 is preferable. More
preferably, as shown in FIG. 12, the surface of a conductor 15 for
buried connection serves as a direct electrode, in terms of a
reduction in the size of the electrode or a reduction in the number
of processes. In addition, the surface of the conductor for buried
connection may serve as a connector connection portion in addition
to a direct measuring electrode (the working electrode, the
reference electrode, or the counter electrode). The measuring
electrode group and the connector connection portion are not
necessarily formed in the same plane, but may be disposed on the
front and rear surfaces. In this case, it is possible reduce the
load of the mask design during vapor deposition. In this structure,
particularly, in the structure in which the wiring lines or the
electrodes are buried, a multi-layer wiring layer may be
manufactured by techniques related to WO/2003/056889. In addition,
a laser beam drilling method or a build-up method using filled
copper plating that has generally been known may be used.
[0264] The structure has been described in which the uppermost
surface is coated with gold and the carbon including layer is
provided as the base layer thereof. However, the base layer of the
uppermost layer may be a nickel layer or a palladium. In this case,
the same effects as described above are obtained.
[0265] FIGS. 13 and 14 show an example of the multi-layer wiring
line. As the structure in which the surface of the conductor 15 for
buried connection is arranged at least on the connector connection
portion in addition to the measuring electrode arranged on the
uppermost surface, as shown in FIG. 13, the surface of the
conductor 15 for buried connection that is exposed by polishing a
connection substrate may be arranged. In FIG. 13, the interface
between the conductor 15 for buried connection and the electrode 18
(when the conductor 15 for buried connection is disposed on the
upper side and the electrode 18 is disposed on the lower side) has
a laminated structure of copper/nickel/copper, and the uppermost
surface of the conductor 15 for buried connection is a direct gold
surface, and the interface between the conductor 15 for buried
connection and the electrode 18 (when the conductor 15 for buried
connection is disposed on the lower side and the electrode 18 is
disposed on the upper side) is a bonded surface of direct gold and
direct gold.
[0266] In order to arrange a transfer wiring line in the connector
connection portion in addition to the measuring electrode, as shown
in FIG. 14, the surfaces of the conductors 15 for connection of the
connection substrate may face each other. In FIGS. 13 and 14,
substantially the same components as those shown in FIGS. 4 to 12
are denoted by the same reference numerals.
[0267] In FIGS. 13 and 14, a coverlay film 30A (polyimide) with an
adhesive layer 30B as shown in the drawings may be used for coating
the coverlay 30. In addition, the entire insulating substrate may
be made of a liquid crystal polymer, the coverlay may be also made
of the liquid crystal polymer, portions of the insulating substrate
and the coverlay may be removed and reccesed by a router apparatus
in advance, and the insulating substrate and the coverlay may be
laminated to each other and then bonded to each other by a vacuum
press at a temperature of 250.degree. C. to 300.degree. C. for 5
minutes. That is, the entire insulating substrate may be made of a
liquid crystal polymer. Alternatively, two coverlays may be
prepared, and openings may be formed in the coverlays such that the
diameter of the opening in the upper coverlay is less than that of
the opening in the lower coverlay. The recession structure
manufactured in this way and the structure to which the formation
of the carbon including layer is applied is substantially the same
as the structure shown in FIGS. 8 and 9. After the coverlays are
prepared, openings may be collectively formed in the upper
coverlays and the lower coverlays by drilling. Therefore, it is
possible to significantly improve productivity, as compared to a
chemical process. As such, the substrate in which the coverlay has
the recession structure and the carbon including layer is formed on
at least the electrode may be used as a mounting substrate.
(Organic Monolayer)
[0268] It is preferable that an organic monolayer be formed on at
least a portion of the uppermost surface of the working electrode
in order to improve the sensitivity or selectivity of a sensor and
improve the flowability or durability of the surface, as compared
to the structure in which the electrode is exposed.
[0269] It is preferable that an organic molecular film having a
substituent group including at least one selected from the group
consisting of chlorine, bromine, sulfur, nitrogen, and oxygen on
the surface thereof be used as the organic monolayer. Specifically,
any of the following organic monolayers may be used: an organic
monolayer having a substituent group including olefin, calboxylic
acid, amine, amide, or pyrrole formed on gold; and an organic
monolayer in which organic molecules having the above-mentioned
substituent group are bonded to each other on carbon by covalent
bonding. Among the organic monolayers, the organic monolayer having
the substituent group including olefin or pyrroles is
preferable.
[0270] In order to form the organic monolayer, any of the following
methods is used: a method using a gold-sulfur covalent bonding
reaction of gold and thiol or disulfide; and a method of covalently
bonding chalcogen of, for example, sulfur or oxygen, or nitrogen or
carbon to the surface in which halogen of bromine or chlorine is
introduced to carbon. These films are immersed in a solution and
are formed by a self-organized reaction with gold.
<Sensor System>
[0271] Next, a sensor system according to the invention will be
described. The sensor system according to the invention includes
the sensor according to the invention, a measuring device that
measures voltage-current characteristics between at least two
electrodes among the electrodes of the sensor, that is, a measuring
device that quantitatively measures (analyzes) analysis information
from the sensor, a connector and a wiring member (which are
optional) that electrically connect the sensor and the measuring
device, a pre-processing unit that neutralizes or filters a liquid
to be analyzed or makes the liquid hardly soluble, and an analysis
liquid container for the pre-process.
[0272] As the measuring device in the sensor system according to
the invention, a measuring device for cyclic voltammetry may be
used. In addition, the connector, the wiring member, and the
analysis liquid container are not particularly limited, but those
generally used in this technical field may be used. The
pre-processing unit will be described below.
<Portable Sensor System>
[0273] A portable sensor system according to the invention includes
at least the sensor according to the invention, a measuring device
that measures voltage-current characteristics between at least two
electrodes among the electrodes of the sensor, and a portable
container that accommodates at least the sensor and the measuring
device.
[0274] In the portable sensor system according to the invention,
connectors and wiring lines for electrically connecting the sensor
and the measuring device are accommodated in the portable
container, and the portable sensor system is handy to carry. In
addition, it is possible to improve user convenience.
[0275] FIG. 41 is a perspective view illustrating an example of the
portable sensor system according to the invention. A portable
sensor system 100 shown in FIG. 41 is an example in which a
portable trunk case 102 is used as a portable container. The trunk
case 102 includes a main body and a cover that is hinged to the
main body so as to be openable. FIG. 41 shows the opened state of
the trunk case 102. The main body of the trunk case 102
accommodates, for example, a notebook personal computer 104 that
processes instruction signals and data from a measuring device, a
mouse 106, an AC adapter 108, and cables. The measuring device is
provided below the notebook personal computer. In addition, a small
object accommodating pocket 110 is provided inside the cover, and
the small object accommodating pocket 110 accommodates a sensor
substrate, a controller for controlling the electrochemical
measurement of the measuring device (which is software backup and
is installed in the notebook personal computer), connectors and
wiring lines, materials required for measurement (small objects:
for example, gloves and an eye protector), and additives used for
analysis (for example, a silver nitrate solution). The trunk case
102 is designed such that, when the cover is closed, the small
object accommodating pocket 110 having small objects accommodated
therein does not come into contact with the notebook personal
computer 104. In addition, a space for accommodating the measuring
device is provided below the notebook personal computer, and an
insulating material and/or a shock absorber absorb vibration when
the portable sensor system is carried. In addition, heat
dissipation during measurement is also considered.
[0276] When the portable sensor system 100 is carried to a
measurement place and measurement is performed, the trunk case 102
is opened, and the sensor substrate, the measuring device, the
controller for controlling the electrochemical measurement of the
measuring device, the connectors, and the wiring lines accommodated
in the small object accommodating pocket 110 are taken out. The
notebook personal computer 104, the measuring device, and the
sensor substrate are connected to each other by the connectors and
the wiring lines. The notebook personal computer 104 may be taken
out from the main body and then used, or it may be used while being
accommodated in the main body. It is difficult to use the AC
adapter 108 in the place where domestic power is not available. The
notebook personal computer 104 may be operated by a built-in
battery and the built-in battery may supply power to the measuring
device. In this case, instructions are transmitted from software to
the measuring device and the notebook personal computer 104, and
data is transmitted therebetween through a USB interface. Power is
supplied from the USB interface.
[0277] That is, in the portable sensor system 100, all components
required for measurement are accommodated in trunk case 102, and
the portable sensor system 100 can be freely carried when the cover
of the trunk case 102 is closed. Therefore, it is possible to carry
the portable sensor system 100 to any desired place and freely
perform measurement. In FIG. 41, the trunk case is given as an
example of an accommodating container, but the invention is not
limited thereto. For example, any case may be used as long as it
can be carried while accommodating the components. The sensor
system according to the invention is a total of about 8 kg in a
standard system structure. In the portable sensor system according
to the invention, it is possible to significantly reduce the
weights of the trunk case, the notebook personal computer, and the
measuring device. Therefore, it is possible to significantly reduce
the weight of the portable sensor system (for example, 2 kg or
less).
[0278] The portable sensor system according to the invention is
different from the related art in that the sensor system according
to the invention is portable. The description of the measuring
device described in the sensor system according to the invention,
or the description of an analysis method using the sensor system
according to the invention is appropriate as the description of the
portable sensor system according to the invention. Therefore, the
portable sensor system according to the invention can acquire
desired data in a measurement place during measurement and analysis
by the sensor system according to the invention.
(Pre-Processing Unit)
[0279] Next, for example, a pre-processing unit for quantitatively
analyzing a monovalent copper chemical species will be described,
but the invention is not limited thereto. Various modifications and
other aspects of the invention can be made within the scope and
spirit of the invention.
[0280] When the monovalent copper chemical species is
quantitatively analyzed, it is an important technique to
pre-process a mixture thereof in various ways.
[0281] In order to perform a chemical pre-process, two kinds of
cooper sulfate (CuSO.sub.4) shown in FIGS. 15 and 16 have been
considered. That is, as shown in FIG. 15, as one method, after a
neutralizing process is performed with sodium hydroxide, a process
of making cooper sulfide hardly soluble with sodium sulfide is
performed to extract monovalent copper ions. As shown in FIG. 16,
another method is to make copper hydroxide hardly soluble with
excessive sodium hydroxide. The obtained solid is filtered by
cotton or an appropriate porous filter, and the filtering solution
is analyzed in each step, which will be described below, to detect
the amount of monovalent copper ions while reducing the influence
of an excess amount or a very small amount of analysis preventing
material in a mixture.
[0282] For example, a twin-peak kit shown in FIG. 17 may be used
for filtering. The twin-peak kit is made of a polypropylene resin
with high heat resistance.
[0283] The twin-peak kit shown in FIG. 17 has the following
structure. A cylinder 62, which is an analysis liquid container, is
a container into which a liquid to be analyzed is introduced and
then a neutralizing agent and an agent for making the liquid hardly
soluble are introduced, or a container into which an encapsulated
neutralizing agent and an encapsulated agent for making the liquid
hardly soluble are introduced. A piston 68 is pressed after the
liquid to be analyzed introduced into the cylinder 62, which is an
analysis liquid container, reacts and transmits the liquid to the
filter 66. The piston 68 may have an additional function of
breaking capsules, if necessary. The liquid filtered by the filter
66 flows into the cylinder 64, which is an analysis liquid
container, and a piston 70 with a sensor 10 is pressed. An air hole
65 is an air outlet for preventing the inverse current of the
liquid.
[0284] In the twin-peak kit shown in FIG. 17, the filter unit may
be omitted and two individual cylinders may be used, which is a
simple structure. FIG. 18(A) is a perspective view illustrating the
structure. In the kid shown in FIG. 18(A), pockets (concave
portions) for mounting two cylinders are provided in the bottom of
a tray 94, which is a temperature-controlled tank. In FIG. 18(A),
cylinders 90 and 92 are provided in the pockets. As shown in FIG.
18(B), two cutouts 90A are provided in the inner wall of the
cylinder 90 so as to extend to the bottom, and the sensor substrate
10 is provided such that both ends thereof are fitted and fixed to
the two cutouts 90A. Although not shown in the drawings, the
cutouts are provided in the cylinder 92.
[0285] The tray 18 has a tank shape and can be filled up with a
liquid, for example, cold water to cool the mounted cylinders.
Therefore, for example, when the cylinder is filled up with a
plating solution at a relatively high temperature, the cylinder can
be rapidly cooled to a temperature range in which there is little
temperature variation over time by the cold water in the tray 18.
FIG. 42 is a graph illustrating a variation in the temperature of
an analyzing solution over time when the kit shown in FIG. 18 is
used to cool the analyzing solution in the cylinder and when the
analyzing solution in the cylinder is not cooled. As can be seen
from the comparison between when the analyzing solution is cooled
and when the analyzing solution is not cooled in FIG. 42, the time
required to reach 25.degree. C. where there is little temperature
variation over time in the former is 5 minutes, which is half the
time required to reach 25.degree. C. in the latter. Therefore, it
is possible to reduce the waiting time to analysis. In FIG. 18, two
cylinders are provided, but the number of cylinders is not limited
thereto. Any number of cylinders may be provided. In addition, a
cooling medium is not limited to the cold water, but other cooling
media may be used.
[0286] In the following examples, this kit is appropriately
used.
<Method of Analyzing Metal Ions>
[0287] Next, a method of analyzing metal ions according to the
invention will be described. As the method of analyzing metal ions,
there are the following two aspects: an aspect that uses the
above-mentioned sensor system to directly analyze a liquid to be
analyzed without performing a pre-process; and an aspect that
performs a pre-process to analyze a liquid to be analyzed.
[0288] In the latter aspect that performs the pre-process to
analyze the liquid to be analyzed, preferably, any of the following
methods is used: (1) a method of neutralizing and filtering a
liquid to be analyzed and analyzing the liquid to be analyzed using
a colorimetric method; (2) a method of neutralizing and filtering a
liquid to be analyzed and analyzing the liquid to be analyzed using
an electrochemical method or a surface potential measuring method;
(3) a method of neutralizing a liquid to be analyzed, making the
liquid to be analyzed hardly soluble, filtering the liquid to be
analyzed, and analyzing the liquid to be analyzed using the
electrochemical method or the surface potential measuring method;
(4) a method of making a liquid to be analyzed hardly soluble,
filtering the liquid to be analyzed, and analyzing the liquid to be
analyzed using the electrochemical method or the surface potential
measuring method; and (5) a method of making a liquid to be
analyzed hardly soluble and analyzing the liquid to be analyzed
using the electrochemical method or the surface potential measuring
method.
[0289] The method of neutralizing the liquid to be analyzed and
making the liquid to be analyzed hardly soluble has been described
with reference to FIGS. 15 and 16.
(Colorimetric Method)
[0290] Next, for example, the colorimetric method for analyzing a
monovalent copper chemical species will be described, but the
invention is not limited thereto. Various modifications and other
aspects of the invention can be made within the scope and spirit of
the invention.
[0291] When the monovalent copper chemical species is
quantitatively analyzed, it is an important technique to
quantitatively determine whether there is a monovalent copper
chemical species in a mixture to be analyzed based on a variation
in the color of the mixture.
[0292] As shown in FIG. 19, an acid solution of copper sulfate
(CuSO.sub.4) including 0.1 to 2.0 mM of monovalent copper ions is
processed according to the method of making a liquid hardly soluble
shown in FIG. 16 and a variation in the color thereof is checked.
That is, when 4 equivalent of excess sodium hydroxide is added to
the acid solution, copper sulfate (CuSO.sub.4) is hardly soluble as
copper hydroxide (Cu(OH).sub.2) from the solution. When the
solution is filtered by cotton or a filter having porous with a
diameter of about 1 .mu.m, and sodium sulfide is added to the
filtered solution. The inventors' examination proved that the
colorimetric method was used to check about 1 mM of more of
monovalent copper ions.
<Cyclic Voltammetry and Surface Potential Method
(Electrochemical Method)>
[0293] Hereinafter, for example, an electrochemical method for
quantitatively analyzing a monovalent copper chemical species will
be described, but the invention is not limited thereto. Various
modifications and other aspects of the invention can be made within
the scope and spirit of the invention.
EXAMPLES
Example 1
[0294] As shown in FIGS. 15 and 20, an acid solution of copper
sulfate (CuSO.sub.4) including about 0.1 to 10 mM of monovalent
copper ions was processed to check a difference in cyclic
voltammetry. That is, first, a solution was neutralized by an
equivalent of sodium hydroxide and sodium sulfide was added to the
neutralized solution. As a result, a blackish brown hardly soluble
deposit occurred. The solution was filtered and a self-assembled
film that was made of nonanedithiol and was disposed on a gold
(111) plane was immersed in the obtained filtrate for two minutes.
Then, the film was taken out and rinsed with 0.1 M of potassium
peroxide solution once. Then, cyclic voltammetry was performed in
20 mM of potassium peroxide solution. In this case, three
electrodes, that is, a silver/silver chloride electrode serving as
the reference electrode, a platinum substrate with a thickness of 1
mm and a size of about 5 mm.times.about 10 mm, serving as the
counter electrode, and a self-assembled film (area: about 0.25
m.sup.2), serving as the working electrode, subjected to the
above-mentioned process, were used to analyze the dependence of a
current on a voltage while changing the voltage from +300 mV to
-200 mV. As shown in FIG. 21, the results proved that, when the
solution including only the copper sulfate (CuSO.sub.4) was
analyzed, the maximum value of the current or the integral value of
the current was not obtained as a significant CV signal, but when
there was a monovalent copper ion, the maximum value of the current
or the integral value of the current was obtained as a CV signal
around about -120 mV and about +200 mV according to concentration.
FIG. 21 shows a graph in which the vertical axis indicates an
electrochemical current value and the horizontal axis indicates the
differential value of the potential of the working electrode. It is
possible to quantitatively analyze the concentration of the
monovalent copper ions in the copper sulfate (CuSO.sub.4) solution
using this method in an indirect manner.
Example 2
[0295] Next, a silver/silver chloride electrode, serving as the
reference electrode, that was electrochemically used was immersed
in a liquid to be analyzed. A Pt electrode with a size of about 10
mm.times.about 10 mm, serving as the counter electrode, was
immersed in the liquid to be analyzed. A square plate which had one
side with a length of about 5 mm and in which gold was coated with
a thickness of 500 nm on mica by vapor deposition, serving as the
working electrode, was immersed in the liquid to be analyzed. The
electrodes were connected to Potentiostat PGSTAT12 for cyclic
voltammetry manufactured by AutoLab Instrument. An acid solution of
monovalent copper ions subjected to nitrogen bubbling was added as
the liquid to be analyzed to prepare a mixed acid solution of 0.2
to 3.3 mM of monovalent copper ions including an excess sulfuric
acid. The three electrodes were immersed in each monovalent copper
ion solution. The working electrode was swept from +0.2 V to +2.0 V
and the oxidation wave thereof was observed. As a result, in this
case, the maximum value of current or the integral value of current
was observed as a CV signal corresponding to the monovalent copper
ion around +1.15 V. FIG. 22 is a graph in which the intensity of
the maximum value of current is plotted as concentration. However,
since the position where the maximum value of current is observed
is changed depending on the surface state of the reference
electrode or the working electrode, the position is not limited to
+1.15 V by a combination thereof or the usage thereof. In addition,
the integral value of the current relative to the voltage may be
used instead of the maximum value. This is the same as that in the
following examples, and the position or range where the maximum
value of the current for the analysis method or the integral value
of the current is observed may be changed or other analysis aspects
may be used within the technical scope of the invention. The
changes are also included in the invention.
[0296] It is possible to quantitatively analyze the concentration
of monovalent copper ions based on the results using this
method.
Example 3
[0297] Next, a square plate which had one side with a length of
about 5 mm and in which tough carbon was coated with a thickness of
100 nm on a glass epoxy resin substrate by vapor deposition,
serving as the reference electrode, was immersed in a liquid to be
analyzed. A rectangular plate with a size of about 10
mm.times.about 10 mm in which tough carbon was coated with a
thickness of 100 nm on a glass epoxy resin substrate by vapor
deposition, serving as the counter electrode, was immersed in the
liquid to be analyzed. A square plate which had one side with a
length of about 5 mm and in which gold was coated with a thickness
of 500 nm on mica by vapor deposition, serving as the working
electrode, was immersed in the liquid to be analyzed. The
electrodes were connected to Potentiostat PGSTAT12 for cyclic
voltammetry manufactured by AutoLab Instrument. An acid solution of
monovalent copper ions was added as the liquid to be analyzed to an
aqueous solution including about 200 mM of copper sulfate
(CuSO.sub.4) including about 0.5 M of sulfuric acid subjected to
nitrogen bubbling, thereby preparing a mixed acid solution of 0.2
to 1.7 mM of monovalent copper ions including excess copper sulfate
(CuSO.sub.4). The three electrodes were immersed in each monovalent
copper ion solution. The working electrode was swept from +0.2 V to
+2.0 V and the dependence of current on the voltage between the
electrodes was observed. As a result, the maximum value of current
or the integral value of current was observed as a CV signal
corresponding to the monovalent copper ion around +0.7 to 0.8 V. In
this case, a value obtained by subtracting the maximum value of
current or the integral value of current with respect to a voltage,
which was obtained from a reference liquid including only the
copper sulfate (CuSO.sub.4), from the maximum value of current or
the integral value of current with respect to the voltage, which
was obtained from a liquid to be analyzed including the monovalent
copper ions, was used. For example, as represented by a solid line
in FIG. 23, the value of the current serving as the CV signal
varied when the voltage of the working electrode was changed, and
the absolute value of the current was the maximum at a given
voltage. In the example shown in FIG. 23, the maximum value is
substantially proportional to the concentration of the monovalent
copper ion, which is one kind of monovalent copper chemical species
to be analyzed. When a variation in the current flowing between the
electrodes with respect to the voltage is small, it is possible to
know the concentration of a chemical species to be analyzed based
on the integral value of the current with respect to the voltage.
In Example 3, for example, as shown in FIG. 23, a value obtained by
subtracting the maximum value of current, which was observed around
0.78 V and was obtained from a reference liquid including only
copper sulfate (CuSO.sub.4) as represented by a dotted line in FIG.
23, instead of the mixed acid solution of monovalent copper ion
including excess copper sulfate (CuSO.sub.4), from the maximum
value of current, which was a CV signal observed around 0.78 V of a
mixed acid solution of 0.91 mM of monovalent ions as represented by
a solid line in FIG. 23, was analyzed as the intensity of the CV
signal. However, instead of the maximum value, the integral value
of the current with respect to the voltage might be used. When a
variation in the current flowing between the electrodes with
respect to the voltage became complicated due to a plating
preventing chemical species in the copper plating solution to be
analyzed, which was being used, a compound produced when copper
plating was used, or the interaction among a plurality of chemical
species selected from monovalent copper chemical species, it was
possible to know the concentration of a chemical species to be
analyzed based on the integral value of the current with respect to
the voltage with a specific voltage range. Since the position where
the maximum value of current is observed is changed depending on
the surface states of the electrodes, the position is not limited
by a combination thereof or the usage thereof. In Example 3, a
voltage value of 0.705 V represented by a dotted line is used as a
reference value (also referred to as a base line), but the analysis
method is not limited thereto. The reference values of other
portions may be used. In addition, the entire CV signal curve of
the reference liquid including only the copper sulfate (CuSO.sub.4)
before being used, which represented in the dotted line in FIG. 23,
may be horizontally moved and used as a reference for analyzing the
maximum value or the integral value. This is the same as that in
Examples other than Example 3, and the position or range where the
maximum value of the current for the analysis method or the
integral value of the current is observed may be changed or other
analysis aspects may be used within the technical scope of the
invention. The changes are also included in the invention. FIG. 24
is a graph in which the obtained maximum value of current is
plotted at each concentration of the monovalent copper ions.
[0298] According to these results, it is possible to analyze the
concentration of monovalent copper ions by using the surface of a
carbon material, without using the Ag/AgCl reference electrode and
the Pt counter electrode according to the related art and being
affected by excess sulfuric acid and excess copper sulfate
(CuSO.sub.4) that coexist with each other. It is possible to
analyze a chemical species in the same way as described above in
Examples other than Example 3.
Example 4
[0299] Next, a method of analyzing a variation in surface potential
(hereinafter, referred to as OCP (Open Circuit Potential)) will be
described. An Ag/AgCl electrode was used as the reference
electrode, and a molecular film was formed on the gold (111) plane
which had a size of 1 cm.times.2 cm and in which gold was coated
with a thickness of 200 nm on mica to form the sensor. Potassium
sulfate was used as supporting salt.
[0300] A sensor in which a calboxylic acid derivative was absorbed
to gold was used. A gold electrode made of a relatively inactive
metal material was used as the reference electrode. The electrode
had a spherical shape and the diameter thereof was in the range of
about 1 mm to 3 mm. The sensor acted on copper ions with high
affinity with a calboxylic acid in an aqueous solution including
0.1 M of potassium sulfate. As a result, after the action, the OCP
was changed (FIG. 25). The change was relatively large before and
after about 200 mV. In Example, the type of host molecule is not
particularly limited, but the molecular film used in the sensor may
be used as a surface potential molecular sensor as long as it can
react with a specific guest molecule.
Example 5
[0301] In Example 5, the analysis of a chemical species in a
plating solution will be described using the sensor substrate
according to the invention, but the invention is not limited
thereto. Various modifications and other aspects of the invention
can be made within the scope and spirit of the invention.
[0302] In an actual copper plating solution (including 0.28 mol/L
of copper sulfate, 2 mol/L of sulfuric acid, and other additives;
and pH<<1), it is possible to analyze the difference between
components of an initial make-up bath copper plating solution and
components of the copper plating solution that is used, using the
sensor substrate and the analysis method according to the
invention. That is, first, 1 mL of silver nitrate aqueous solution
with a concentration of 14 mmol/L was added to 10 mL of plating
solution, which is an analysis target. After two minutes, a muddy
liquid was filtered by a syringe filter having porous with a
diameter of 0.45 .mu.m, and the filtrate was moved to an analysis
liquid container with a diameter of about 2.5 cm and a height of
about 3 cm. The diameter of the porous of the syringe filter may be
equal to or less than 0.45 .mu.m. Then, the sensor substrate having
a width of 17 mm and a length of 34 mm according to the invention
in which the outermost surface of the electrode group arranged on
the insulating organic substrate (Polyimide) shown in FIG. 1 was
entirely coated with gold or partially coated with carbon was
connected to the potentiostat through a connector, and the
electrode group of the sensor substrate was immersed in the
obtained liquid. In this case, it is necessary the liquid level
does not come into contact with a connection terminal group. When
the distance to the electrode or the electrode group is 1 mm or
more in consideration of the meniscus effect, it is possible to
avoid the contact between the liquid level and the connection
terminal group. The connection terminal group is likely to come
into contact with the liquid level due to the evaporation or
vibration of the liquid, and noise is likely to occur during
measurement. Therefore, it is preferable that the distance be 3 mm
or more. It is preferable to provide a blocking plate that prevents
the evaporation of a liquid including an analyte from the liquid
level between the connection terminal group and the liquid level.
Then, the voltage applied to the working electrode in the range of
+0.2 V to +2.0 V, which was an electrochemically effective initial
state, was swept at a speed of 20 mV/sec, and the dependence of a
current with respect to the voltage between the electrodes was
observed at a room temperature.
[0303] The term "electrochemically effective initial state" means a
state where at least an oxidation wave, a reduction wave, or a
combination thereof is applied before measurement starts or an
operation of immersing a substrate in chemicals, such as acid,
alkali, and solvent, is performed before measurement starts to
remove an organic material or an oxide remaining on the surface,
such that measurement can be repeatedly performed in a stable
state.
[0304] The observation results proved that the maximum value of the
current or the integral value of the current, which was a
significant CV signal, was in the range of about +0.7 V to +1.0 V
in the copper plating solution that was used, as compared to the
current cyclic voltammetry (CV) when an initial make-up bath copper
plating solution was analyzed. The maximum value of the current or
the integral value of the current, which is a significant CV
signal, corresponds to a produced compound included in only the
copper plating solution that is used on the spot. The CV
measurement and X-ray photoelectron spectroscopy showed that about
36 mM of produced compound was included in the copper plating
solution that was used in Example 4. The concentration of the
produced compound in the liquid subjected to the above-mentioned
process was changed and the intensity of a corresponding CV signal
was analyzed. As described in Example 3, the actual data was a
value obtained by subtracting the maximum value of the current or
the integral value of the current with respect to the voltage
obtained from the initial make-up bath copper plating solution from
the maximum value of the current or the integral value of the
current with respect to the voltage obtained from the copper
plating solution that was used. In this case, the maximum value of
the current was output as the intensity of the CV signal. As a
result, as can be seen from FIG. 26, 2 parameters are proportional
to each other. From the above results, according to the invention,
it is possible to analyze the concentration of a produced compound
on the spot.
[0305] However, it is possible to analyze the concentration of a
produced compound only from the CV signal of the copper plating
solution that is being used, which is included in the produced
compound, without subtracting the CV signal of the initial make-up
bath copper plating solution as a reference. In addition, the sweep
speed of the voltage applied to the working electrode is not
limited to 20 mV/sec. Even when the sweep speed is about 5 digits
or about -2 digits according to the area of the electrode, it is
possible to analyze a produced compound.
Example 6
[0306] Next, Example 6 according to the invention relates to a
structure capable of analyzing an analysis target without a
filtering operation in addition to Example 5. First, in an analysis
liquid container with a diameter of about 2.5 cm and a height of
about 3 cm, 1 mL of silver nitrate aqueous solution with a
concentration of 14 mmol/L was added to 10 mL of plating solution,
which was an analysis target. After two minutes, a sensor substrate
having a width of 17 mm and a length of 34 mm according to the
invention in which the outermost surface of the electrode group
arranged on the insulating organic substrate (Polyimide) shown in
FIG. 1 was entirely coated with gold or partially coated with
carbon was connected to the potentiostat through a connector, and
the electrode group of the sensor substrate was immersed in the
obtained liquid. Then, the voltage applied to the working electrode
in the range of +0.2 V to +2.0 V, which was an electrochemically
effective initial state, was swept at a speed of 20 mV/sec, and the
dependence of a current with respect to the voltage between the
electrodes was observed at a room temperature. In Example 6, the
following method was used to obtain the electrochemically effective
initial state. That is, first, the sweep speed of the voltage
applied to the working electrode was 200 mV/sec, and a sweep cycle
from the minimum value to the maximum value and from the maximum
value to the minimum value in the set voltage range was performed
10 times. Then, after 5 seconds, similarly, the sweep cycle was
performed 5 times, and after 5 seconds, for example, the minimum
value +0.2 V in the voltage range was set to the initial state.
[0307] The observation results proved that the maximum value of the
current or the integral value of the current, which was a
significant CV signal, was in the range of about +0.7 V to +1.0 V
in the copper plating solution that was used, as compared to the
cyclic voltammetry (CV) when an initial make-up bath copper plating
solution was analyzed. The maximum value of the current or the
integral value of the current, which is a significant CV signal,
corresponds to a produced compound included in only the copper
plating solution that is used on the spot. The CV measurement and
X-ray photoelectron spectroscopy showed that about 36 mM of
produced compound was included in the copper plating solution that
was used in Example 4. The concentration of the produced compound
in the liquid subjected to the above-mentioned process was changed
and the intensity of a corresponding CV signal was analyzed. As
described in Example 3, the actual data was a value obtained by
subtracting the maximum value of the current or the integral value
of the current with respect to the voltage obtained from the
initial make-up bath copper plating solution from the maximum value
of the current or the integral value of the current with respect to
the voltage obtained from the copper plating solution that was
used. In this case, the maximum value of the current was output as
the intensity of the CV signal. As a result, as can be seen from
FIG. 27, 2 parameters are proportional to each other. However,
there was a little difference between the inclination of a straight
line in FIG. 27 and the inclination of a straight line in FIG. 26.
It is considered that the difference is caused by the influence of
silver salt, the influence of temperature variation, a variation in
the sensor substrate, and the analysis time, and the influence of
air oxidation.
[0308] However, the following changes may be made within the scope
of the invention: a change in the volumes of a plating solution and
a silver nitrate aqueous solution, which are analysis targets; a
change in the size of the sensor substrate; a change in the
electrochemically effective initial state for an analysis method; a
change in the position or range where the maximum value of current
or the integral value of current is observed; and a change in other
analysis aspects. The changes are also included in the invention.
The sweep speed of the voltage applied to the working electrode is
not limited to 20 mV/sec. Even when the sweep speed is about 5
digits or about -2 digits according to the area of the electrode,
it is possible to analyze a produced compound.
[0309] From, the above-mentioned results, according to the
invention, it is possible to analyze a produced compound included
in a copper plating solution on the spot by considering the average
of an error, such as variation, or the uniformity of analysis
conditions.
[0310] In Examples 5 and 6, silver nitrate is used as a solution (a
chemical species forming a hardly-soluble compound with an analysis
preventing material) for making an analysis preventing material
hardly soluble, but the invention is not limited thereto. For
example, monovalent mercury ions or thallium ions may be used to
make the analysis preventing material hardly soluble. In addition,
a cationic species forming appropriate hardly-soluble salt, a
chemical species having the same function, a polymer analog
material, an activated carbon material, or a zeolite analog
material may be used to make the analysis preventing material
hardly soluble.
Example 7
[0311] Next, Example 7 according to the invention relates to a
structure capable of analyzing an analysis target using a sensor
with a different shape, without a filtering operation, in addition
to Example 5. First, in an analysis liquid container with a
diameter of about 2.5 cm and a height of about 3 cm, 1 mL of silver
nitrate aqueous solution with a concentration of 14 mmol/L was
added to 10 mL of plating solution, which was an analysis target.
After two minutes, three gold wires (conductive lines) which had a
diameter of 1 mm and were coated with an insulating organic polymer
and in which the insulating organic polymer of a portion thereof
that was 5 mm from the end was removed were immersed in the
above-mentioned liquid, and the exposed portions of the gold wires
corresponded to the working electrode, the counter electrode, and
the reference electrode. In addition, the insulating organic
polymer coated on other portions of the gold wires separated from
the exposed portions was removed to form other exposed portions of
the gold wires as connection terminals. Then, the connection
terminals were connected to the potentiostat so as to correspond to
action, opposite, and reference portions. However, the gold wires
(conductive lines) might be cut and the cut surfaces might
correspond to the working electrode, the counter electrode, and the
reference electrode. Then, the voltage applied to the working
electrode in the range of +0.2 V to +2.0 V, which was an
electrochemically effective initial state, was swept at a speed of
20 mV/sec, and the dependence of a current with respect to the
voltage between the electrodes was observed at a room temperature.
The observation results proved that the maximum value of the
current or the integral value of the current, which was a
significant CV signal, was in the range of about +0.7 V to +1.0 V
in the copper plating solution that was used, as compared to the
cyclic voltammetry (CV) when the initial make-up bath copper
plating solution was analyzed. The maximum value of the current or
the integral value of the current, which is a significant CV
signal, corresponds to a produced compound included in only the
copper plating solution that is used on the spot. The CV
measurement and X-ray photoelectron spectroscopy showed that about
36 mM of produced compound was included in the copper plating
solution that was used in Example 7. The concentration of the
produced compound in the liquid subjected to the above-mentioned
process was changed and the intensity of a corresponding CV signal
was analyzed. As described in Example 3, the actual data was a
value obtained by subtracting the maximum value of the current or
the integral value of the current with respect to the voltage
obtained from the initial make-up bath copper plating solution from
the maximum value of the current or the integral value of the
current with respect to the voltage obtained from the copper
plating solution that was used. In this case, the maximum value of
the current was output as the intensity of the CV signal. As a
result, 2 parameters were proportional to each other (FIG. 28).
From the above-mentioned results, according to the invention, it is
possible to analyze a produced compound included in a copper
plating solution on the spot.
[0312] In Example 7, the insulating organic polymer of the front
portions of the gold wires coated with the insulating organic
polymer is removed. However, the gold wires may be cut, and the
gold sections (cut surfaces) of the gold wires may be exposed.
Alternatively, the gold portions may be peeled off by a combination
thereof.
[0313] The conductive lines used in the invention are not limited
to the gold wires, but any lines may be used as long as the
surfaces thereof are coated with a material that is not soluble by
a liquid or mist including an analyte or a material that is not
corroded by gas including the analyte. For example, a platinum
line, a platinum iridium line, which will be described below, a
copper line plated with gold or platinum, and a line plated with a
carbon containing material may be used.
Example 8
[0314] Next, Example 8 according to the invention relates to a
structure capable of analyzing an analysis target using a sensor
with a different shape, without a filtering operation, in addition
to Example 5. First, the exposed end of a gold wire which had a
diameter 0.25 mm and was coated with an insulator was coated with
an insulator. Then, a portion of the insulator corresponding to
about 2 mm from a point that was about 7 mm from the end was
removed by an appropriate method. In this way, one gold wire whose
gold portion was partially exposed was prepared. Then, the exposed
ends of platinum/iridium (alloy ratio: 9/1) wires which had a
diameter of 0.25 mm and were coated with an insulator were coated
with an insulator. Then, a portion of the insulator corresponding
to about 2 mm from a point that was about 7 mm from the end was
removed by an appropriate method. In this way, two platinum/iridium
wires whose plated portions were partially exposed were prepared.
The exposed portion of the gold wire corresponded to the working
electrode, and the exposed portions of the platinum/iridium wires
corresponded to the counter electrode and the reference electrode.
In addition, other portions (in Example 8, portions opposite to the
exposed portions) of the insulating organic polymer of the gold
wires which were separated from the exposed portions were removed
to form other exposed portions of the gold wires as connection
terminals. The wires were connected to the potentiostat such that
the gold wire corresponded to an action portion and the
platinum/iridium wires corresponded to an opposite portion and a
reference portion. Then, in an analysis liquid container with a
diameter of about 2.5 cm and a height of about 3 cm, 1 mL of silver
nitrate aqueous solution with a concentration of 14 mmol/L was
added to 10 mL of plating solution, which was an analysis target.
After two minutes, the metal exposed portions of the three wires
were immersed in the liquid, and the voltage applied to the working
electrode in the range of +0.2 V to +2.0 V, which was an
electrochemically effective initial state, was swept at a speed of
20 mV/sec. Then, the dependence of a current with respect to the
voltage between the electrodes was observed at a room temperature.
In Example 8, the following method was used to obtain the
electrochemically effective initial state. That is, first, the
sweep speed of the voltage applied to the working electrode was 200
mV/sec, and a sweep cycle from the minimum value to the maximum
value and from the maximum value to the minimum value in the set
voltage range was performed 10 times. Then, after 5 seconds,
similarly, the sweep cycle was performed 5 times, and after 5
seconds, for example, the minimum value +0.2 V in the voltage range
was set to the initial state.
[0315] The observation results proved that the maximum value of the
current or the integral value of the current, which was a
significant CV signal, was in the range of about +0.7 V to +1.0 V
in the copper plating solution that was used, as compared to the
cyclic voltammetry (CV) when the initial make-up bath copper
plating solution was analyzed. The maximum value of the current or
the integral value of the current, which is a significant CV
signal, corresponds to a produced compound included in only the
copper plating solution that is used on the spot. The CV
measurement and X-ray photoelectron spectroscopy showed that about
36 mM of produced compound was included in the copper plating
solution that was used in Example 8. The concentration of the
produced compound in the liquid subjected to the above-mentioned
process was changed and the intensity of a corresponding CV signal
was analyzed. As described in Example 3, the actual data was a
value obtained by subtracting the maximum value of the current or
the integral value of the current with respect to the voltage
obtained from the initial make-up bath copper plating solution from
the maximum value of the current or the integral value of the
current with respect to the voltage obtained from the copper
plating solution that was used. In this case, the maximum value of
the current was output as the intensity of the CV signal. As a
result, 2 parameters were proportional to each other (FIG. 29).
From the above-mentioned results, according to the invention, it is
possible to analyze a produced compound included in a copper
plating solution on the spot.
[0316] However, the following changes may be made within the scope
of the invention: a change in the volumes of a plating solution and
a silver nitrate aqueous solution, which are analysis targets; a
change in the electrochemically effective initial state for an
analysis method; a change in the position or range where the
maximum value of current or the integral value of current is
observed; and a change in other analysis aspects. The changes are
also included in the invention. The sweep speed of the voltage
applied to the working electrode is not limited to 20 mV/sec. Even
when the sweep speed is about 5 digits or about -2 digits according
to the area of the electrode, it is possible to analyze a produced
compound.
Example 9
[0317] Example 9 according to the invention relates to a structure
capable of analyzing an analysis target while making an analysis
preventing material hardly soluble in stages. That is, in an
analysis liquid container with a diameter of about 2.5 cm and a
height of about 3 cm, 1 mL of silver nitrate aqueous solution with
a concentration of 14 mmol/L was added to 10 mL of plating
solution, which was an analysis target. After two minutes, a sensor
substrate having a width of 17 mm and a length of 34 mm according
to the invention in which the outermost surface of the electrode
group arranged on the insulating organic substrate (Polyimide)
shown in FIG. 1 was entirely coated with gold or partially coated
with carbon was connected to the potentiostat through a connector,
and the electrode group of the sensor substrate was immersed in the
obtained liquid. Then, the voltage applied to the working electrode
in the range of +0.2 V to +2.0 V, which was an electrochemically
effective initial state, was swept at a speed of 20 mV/sec, and the
dependence of a current with respect to the voltage between the
electrodes was observed at a room temperature. The observation
results proved that the maximum value of the current or the
integral value of the current, which was a significant CV signal,
was in the range of about +0.7 V to +1.0 V in the copper plating
solution that was used, as compared to the cyclic voltammetry (CV)
when the initial make-up bath copper plating solution was analyzed.
The maximum value of the current or the integral value of the
current, which is a significant CV signal, corresponds to a
produced compound included in only the copper plating solution that
is used on the spot. Then, 20 mL of sodium hydroxide aqueous
solution with a concentration of 2 mol/L was added to the plating
solution analyzed in the first stage. A neutralizing process using
sodium hydroxide may be omitted. Then, about 5.5 mL of sodium
sulfide aqueous solution or sodium polysulfide aqueous solution was
added at a concentration of 0.6 mol/L. After two minutes, a black
solid was filtered, and a portion of the filtrate was moved to an
analysis liquid container with a diameter of about 2.5 cm and a
height of about 4 cm. Then, the sensor substrate having a width of
17 mm and a length of 34 mm according to the invention in which the
outermost surface of the electrode group arranged on an insulating
organic substrate (Polyimide) was entirely coated with gold or
partially coated with carbon was connected to the potentiostat
through a connector, and the electrode group of the sensor
substrate was immersed in the liquid. Then, the voltage applied to
the working electrode in the range of +0.2 V to +2.0 V, which was
an electrochemically effective initial state, was swept at a speed
of 20 mV/sec, and the dependence of a current with respect to the
voltage between the electrodes was observed at a room temperature.
The observation results proved that the maximum value of the
current or the integral value of the current, which was a
significant CV signal, was in the range of about +0.9 V to +1.6 V
in the copper plating solution that was used in the second stage,
as compared to the cyclic voltammetry (CV) when the initial make-up
bath copper plating solution was analyzed. As such, according to
the invention, it is possible to analyze a plurality of produced
compounds in the copper plating solution that is being used in
stages. However, in Example 9, in the second analysis stage, the
black solid is filtered, but analysis may be performed without
filtering. The sweep speed of the voltage applied to the working
electrode, which is used in this analysis, is not limited to 20
mV/sec. Even when the sweep speed is about 5 digits or about -2
digits according to the area of the electrode, it is possible to
analyze a produced compound.
Example 10
[0318] According to the invention, when a variation in the current
flowing between the electrodes with respect to the voltage become
complicated due to a plating preventing chemical species in the
copper plating solution to be analyzed, which is being used, a
compound produced when copper plating is used, or the interaction
among a plurality of chemical species selected from monovalent
copper chemical species, it is possible to know the concentration
of a chemical species to be analyzed based on the integral value of
the current with respect to the voltage with a specific voltage
range. It is possible to analyze a plating preventing chemical
species or a produced compound included in a copper plating
solution on the spot using a value obtained by subtracting the
integral value of the current in the voltage range obtained from
the initial make-up bath copper plating solution from the integral
value of the current in the voltage range obtained from the copper
plating solution that is used. First, 1 mL of silver nitrate
aqueous solution with a concentration of 14 mmol/L was sequentially
added to 10 mL of initial make-up bath copper plating solution and
10 mL of copper plating solution which was used, in two analysis
liquid containers with a diameter of about 2.5 cm and a height of
about 3 cm. After two minutes, three gold wires (conductive line)
which had a diameter of 1 mm and were coated with an insulating
organic polymer and in which the insulating organic polymer of
portions thereof that were 5 mm from the ends were removed were
immersed in the initial make-up bath copper plating solution, and
the exposed portions of the gold wires corresponded to the working
electrode, the counter electrode, and the reference electrode. In
addition, the insulating organic polymer coated on other portions
of the gold wires separated from the exposed portions was removed
to form other exposed portions of the gold wires as connection
terminals. Then, the connection terminals were connected to the
potentiostat so as to correspond to action, opposite, and reference
portions. However, the gold wires (conductive lines) might be cut
and the cut surfaces might correspond to the working electrode, the
counter electrode, and the reference electrode. Then, the voltage
applied to the working electrode in the range of +0.2 V to +2.0 V,
which was an electrochemically effective initial state, was swept
at a speed of 20 mV/sec, and the dependence of a current with
respect to the voltage between the electrodes was observed at a
room temperature. The same measurement was performed on the copper
plating solution that was used. The observation results proved that
the integral value of the current, which was a significant CV
signal, existed at a value of about 1.5.times.10.sup.-6 VA in the
range of about +0.7 V to +0.76 V in the copper plating solution
that was used, as compared to the cyclic voltammetry (CV) when the
initial make-up bath copper plating solution was analyzed. The
integral value of the current, which is a significant CV signal,
corresponds to the plating preventing chemical species or the
produced compound included in only the copper plating solution that
is used. From the above-mentioned results, according to the
invention, it is possible to analyze the plating preventing
chemical species or the produced compound included in only the
copper plating solution on the spot. The sweep speed of the applied
voltage is not limited to 20 mV/sec. Even when the sweep speed is
about 5 digits or about -2 digits according to the area of the
electrode, it is possible to perform analysis. In addition, the
position or range where the integral value for an analysis method
is objected may be changed and other analysis aspects may be
changed within the sprit and scope of the invention. The changes
are also included in the invention.
Example 11
[0319] The method according to the invention was affected by the
temperature, which was checked by the following analysis. That is,
the CV of a monovalent copper chemical species in the copper
plating solution that was used was analyzed by the sensor substrate
according to the invention while changing the temperature of the
solution. First, in Example 11, the intensity of the CV signal of
the monovalent copper chemical species observed at about +0.82 V
was about 10 .mu.A as the maximum current value at a room
temperature of 25.degree. C., about 17.5 .mu.A at a temperature of
40.degree. C., and about 55 .mu.A at a temperature of 80.degree. C.
That is, as the temperature was increased, the maximum current
value was increased. In addition, the base line of an
electrochemical current at a voltage of +0.5 V of the working
electrode was about 12 .mu.A at a room temperature of 25.degree.
C., about 19 .mu.A at a temperature of 40.degree. C., and about 110
.mu.A at a temperature of 80.degree. C. That is, as the temperature
was increased, the base line level of the electrochemical current
was increased. As described above, it is clear that the method
according to the invention is affected by the temperature of the
plating solution, which is an analysis target, and it is important
to return the temperature of a liquid to be analyzed to the room
temperature using a temperature-controlled tank, to make the
temperatures of the liquid to be analyzed and a reference solution
equal to each other in the temperature-controlled tanks which are
disposed in one water tank, to maintain a constant temperature
using a kit for a pre-process or an integrated kit, and to consider
the correction of the temperature. For example, as shown in FIG.
18, two analysis liquid containers 90 and 92 for analysis are
immersed in a temperature-controlled tank 94 filled with
room-temperature water for maintaining a constant temperature, and
the temperature difference between the initial make-up bath copper
plating solution and the copper plating solution that is used in
the two analysis liquid containers 90 and 92 is maintained within
10.degree. C. The depths of the analysis liquid containers may vary
depending on the conditions. In addition, the rate of temperature
change may be used in order to consider the correction of the
temperature. In the invention, the rate of temperature change can
be theoretically defined by the rate of change of the exponential
of a reaction speed from a temperature T.sub.1 to a temperature
T.sub.2 by the Arrhenius equation
(exp(-E/RT.sub.2)/exp(-E/RT.sub.1); R is an integer and E is
reaction activation energy which varies depending on conditions),
and it is possible to correct a difference in analysis temperature
using the equation. However, in the actual surface reaction, it may
be difficult to describe all factors with a simple primary reaction
kinetics. Therefore, it is possible to calculate the rate of
temperature change according to the invention by giving different
equations or correction terms according to the difference between
reaction dimensions or the difference between reaction forms, or by
measuring the rate of temperature change by experiments. The
correction of the temperature using the actually measurement rate
of temperature change is performed as follows. First, a variation
(rate of temperature change) in the maximum value of the current or
the integral value of the current between the electrodes according
to the temperature with respect to a variation in the voltage
between the electrodes in a reference solution according to the
temperature is calculated. This measurement is not changed even
though a mixture of an analysis target is changed. Then, a value
obtained by multiplying the difference between the temperature of
the mixture of the analysis target (in this case, the analysis
target is a plating solution) and the temperature of the reference
solution (in this case, an initial make-up bath copper plating
solution) by the rate of temperature change is added to the maximum
value of the current or the integral value of the current between
the electrodes with respect to a variation in the voltage between
the electrodes in the reference solution, which is measured at the
temperature of the reference solution. A value obtained by
subtracting the value from the maximum value of the current or the
integral value of the current between the electrodes with respect
to a variation in the voltage between the electrodes in a liquid to
be analyzed is used as the maximum value of the current or the
integral value of the current between the electrodes with respect
to a variation in the voltage between the electrodes in the
analysis target.
Example 12
[0320] Example 12 of the invention has an effect of stably
performing analysis without immersing a substrate (depth). The
effect was verified by the following analysis. A copper plating
solution including a monovalent copper chemical species was used as
an analysis target. As schematically shown in FIG. 30, a sensor
according to the invention in which a coverlay was provided on
wiring lines on a polyimide (PI) substrate (FIG. 30(A)) and the
sensor according to the related art in which a gold thin film with
a width of 3 mm was formed on glass by vapor deposition (FIG. 30(B)
were immersed in the copper plating solution, and analysis was
performed while changing the depth (D) of immersion. FIG. 31 is a
graph illustrating the analyze results (graph .largecircle.) when
the sensor according to the invention is used and the analyze
results (graph .quadrature.) when the sensor according to the
related art is used. As can be seen from the graph of FIG. 31, the
sensor according to the invention stably performs analysis
regardless of the depth of immersion, but the analysis result of
the sensor according to the related art varies greatly depending on
the depth of immersion. In Example 12, the coverlay was used as an
insulating portion that was made of an organic material and
insulated the wiring lines, but the insulating portion is not
limited to the coverlay. Any insulating portion may be used as long
as it insulates the wiring lines. In FIG. 30, PI indicates
polyimide, glass indicates glass, W indicates the working
electrode, R indicates the reference electrode, and C indicates the
counter electrode.
Example 13
[0321] Example 13 of the invention has an effect of stably
performing analysis without the immersion state of a substrate
(inclination). The effect was verified by the following analysis. A
copper plating solution including a monovalent copper chemical
species was used as an analysis target. As schematically shown in
FIG. 32, a sensor according to the invention in which a coverlay
was provided on wiring lines on a polyimide (PI) substrate (FIG.
32(A)) and the sensor according to the related art in which gold
wires with a width of 3 mm were formed on glass by vapor deposition
(FIG. 32(B) were immersed in the copper plating solution, and
analysis was performed while changing the angle (.theta.) of
immersion, as shown in FIG. 32. FIG. 33 is a graph illustrating the
analyze results (graph .largecircle.) when the sensor according to
the invention is used and the analyze results (graph .quadrature.)
when the sensor according to the related art is used. As can be
seen from the graph of FIG. 33, the sensor according to the
invention stably performs analysis regardless of the angle of
immersion, but the analysis result of the sensor according to the
related art in which the gold wires with a width of 3 mm are formed
by vapor deposition varies greatly depending on the angle of
immersion. In FIG. 32, PI indicates polyimide, glass indicates
glass, W indicates the working electrode, R indicates the reference
electrode, and C indicates the counter electrode.
Example 14
[0322] As described above, the exposure of the gold-plated portion
that is not covered with the carbon including layer is likely to
prevent analysis. For example, as described in Example 13, similar
to when the area of the electrode varies depending on the angle of
immersion, the gold plated portion that is not covered with the
carbon including layer causes a variation in the area of the
electrode between the sensor substrates. In the recession structure
of the coverlay, it is preferable that the wiring line extend from
the electrode in the thickness direction of the substrate, that is,
the vertical direction, not in the plane direction of the
substrate. According to Example 14 of the invention, in a method of
drawing the wiring line in the plane direction, it is also possible
to ensure reproducibility between the substrates by covering the
gold-plated portion with the carbon including layer, and it is
possible to achieve durability capable of repeatedly performing
measurement with the same substrate. In Example 14, the effects
were verified as follows.
[0323] FIG. 34 is a plan view illustrating a sensor substrate
including nine electrodes. The sensor substrate includes three sets
of a counter electrode (C), a reference electrode (R), and a
working electrode (W). Specifically, a sensor substrate 90 has nine
measuring terminals 92 at the edge thereof, and measuring
electrodes 94A, 94B, 94C, 96A, 96B, 96C, 98A, 98B, and 98C are
connected to the measuring terminals 92 through the wiring lines.
Any three sets of measuring electrodes are used as the counter
electrode (C), the reference electrode (R), and the working
electrode (W). As a connector, a 1 mm pitch connector FH12-9S-1SH
(product number) manufactured by Hirose Electric Co., Ltd. was
used, and the outer width of the substrate and the arrangement of
the terminals were designed according to the connectors. A
polyimide film with a copper foil was used as the substrate. In
this case, the thickness of a terminal portion fitted to the
connector in the substrate thickness including the thickness of the
terminal is 0.3.+-.0.05 mm. A sensor substrate having a
cross-sectional structure shown in FIG. 35 was designed and
manufactured based on the dimensions of the connector. That is, as
shown in FIG. 35, the manufactured sensor substrate has a structure
in which a base polyimide 124 is adhered to a reinforcing plate
polyimide 120 with a thermosetting adhesive layer 122 interposed
therebetween, a copper foil 126 is provided on the base polyimide
124, and a coverlay film (polyimide film) 130 is adhered to the
copper foil 126 with an adhesive layer 128 interposed therebetween.
The thickness of the reinforcing plate polyimide 120 is 180 .mu.m,
the thickness of the thermosetting adhesive layer 122 is 50 .mu.m,
the thickness of the base polyimide 124 is 25 .mu.m, the thickness
of the copper foil 126 is 35 .mu.m, the thickness of the adhesive
layer 128 is 25 .mu.m, and the thickness of the coverlay film
(polyimide film) 130 is 25 .mu.m.
[0324] The coverlay was formed by integrating a polyimide film with
an adhesive. The adhesive was heated in advance to be hardened,
thereby controlling flowability or expanding the clearance. In this
way, the contamination of the electrode by the adhesive was
prevented and a variation in the area of the electrode due to the
flow of the adhesive did not occur. In addition, the coverlay was
adhered to a hatched region in FIG. 36.
[0325] The positional deviation between the electrode and an
opening is large in the plane, which may cause a large variation in
wiring lines in the opening. In Example 14, after the coverlay was
adhered, any of the following preprocesses was performed before
carbon paste was applied: the radiation of oxygen plasma (300 W and
60 seconds); the radiation of UV and ozone (the amount of oxygen
introduced is 0.1 mL/min) for 50 minutes; and immersion in methanol
for 3 minutes (application of US) and immersion in ultrapure water
for 3 minutes (application of US). It was possible to ensure
adhesion stability when an ink jet method was used to apply and
form carbon paste by appropriately selecting the pre-process.
[0326] Then, as the working electrode and the reference electrode,
carbon paste manufactured by HITACHI CHEMICAL CO., LTD was applied
by an ink jet method to form square electrodes with a side length
of 2.9 mm (an opening in the electrode: .PHI.2.5). In addition,
similarly, as the counter electrode, carbon paste was applied to
form a square electrode with a side length of 3.9 mm (an opening in
the electrode: .PHI.3.5). The carbon paste was dried by a heater
having a temperature adjusting function at a temperature of
160.degree. C. for one hour. Then, only the working electrode
portion and the counter electrode portion were exposed and gold was
deposited with a thickness of 2000 .ANG. using the terminal portion
fitted to the connector and the reference electrode as a mask. The
vapor deposition speed is preferably 1.8 .ANG./sec. When control is
unavailable, it is preferable that the vapor deposition speed be in
the range of 0.1 .ANG./sec to 10 .ANG./sec. The substrate
manufactured in this way makes it possible to ensure durability
capable of repeatedly performing measurement with the same
substrate and reproducibility between the substrates.
[0327] Then, the following operation was performed to verify that
the reproducibility between the substrates was ensured. Six
substrates were manufactured by the above-mentioned method, and the
amount of solution used for filled copper plating was measured by
each substrate. As could be seen from FIG. 37, in the reaction of
the electrode with monovalent copper, the base current was
stabilized, and a variation in the potential position of a
monovalent copper peak was removed. Six graphs shown in FIG. 37
show the measurement results of the six substrates.
[0328] However, there is about .+-.20% of variation in the current
value between the substrates from the average value. This tendency
also appears in an initial make-up bath. That is, this is because
the peak of a monovalent copper chemical species overlaps the
oxidation reaction of gold. In this case, R3, C3, and W3 shown in
FIG. 36 were used as the reference electrode, the counter
electrode, and the working electrode.
[0329] Then, carbon paste was applied to the working electrode and
the counter electrode of each of the six substrates, and gold was
deposited thereon by vapor deposition. In this case, R3, C3, and C2
shown in FIG. 36 were used as the reference electrode, the counter
electrode, and the working electrode. That is, the reference
electrode was arranged between the counter electrode and the
working electrode. Then, as shown in the graph of FIG. 38, the
measurement result of an initial make-up bath solution proved that
a variation in the current value was removed. Similar to FIG. 37,
six graphs shown in FIG. 38 show the measurement results of the six
substrates. It was possible to increase the detected current by
increasing the size of the working electrode and arranging the
reference electrode so as to be opposite to the working electrode.
In addition, it was possible to reduce the variation to .+-.7% or
less.
[0330] All the electrodes were formed by directly plating copper
with gold, unlike the structure according to the invention, and the
amount of solution used for filled copper plating was measured. In
this case, the electrode reacted with monovalent copper, as shown
in FIG. 39. As a result, there was a variation in the base current,
the potential position of a monovalent copper peak, or the current
value.
[0331] It is considered that the instability of the base current
and the variation in the potential position of the monovalent
copper peak and the current value are caused by an alloy of gold
and copper on the outer layer and the formation of an oxide on the
surface, according to the cross-sectional observation of the
electrode portion by FIB, an electron microscope, or EDX analysis.
The detailed examination results proved that chrome or nickel as
well as gold could be formed as an underlying layer on the carbon
including layer, and an alloy of gold and copper could be formed.
In addition, it was possible to closely deposit titanium or
titanium oxide using vapor deposition. In this case, in the
gold-copper alloy, the ratio of the weight of gold to the weight of
copper was 9.25:1.
[0332] It was possible to improve the surface roughness of the
electrode during etching by covering the electrode formed by
etching with the carbon including layer. It was possible to reduce
the centerline average roughness from 1500 to 2000 .ANG. to 50
.ANG. by repeatedly performing application and drying three times
or more, and control the centerline average roughness to an atomic
flat level that is equal to the wall interface of mica. In this
way, it is possible to improve the formability of a self-assembled
organic monolayer after gold is deposited by vapor deposition.
[0333] An example using a polyimide film has been described above.
Another example in which a liquid crystal polymer is used as a base
material in the pattern shown in FIG. 34 will be described
below.
[0334] A liquid crystal polymer (manufactured by JAPAN GORE-TEX
INC.) BIAC-C was prepared as a base material, and a copper foil
with a thickness of 12 .mu.m was directly attached to a substrate
with a thickness of 300 .mu.m and then patterned by etching. An
adhesive layer KS-7003 manufactured by HITACHI CHEMICAL CO., LTD.
(25 .mu.m) was adhered to a coverlay with a thickness of 125 .mu.m
by press bonding at a temperature of 110.degree. C., and boring
plates having holes with clearances of +1.0 mm and +0.5 mm (500
.mu.m and 250 .mu.m on one side) with respect to the diameter of
the electrode were prepared. The former that was disposed on the
lower side was temporarily adhered to the latter that was disposed
on the upper side by a pin-lamination method and vacuum pressing
was performed at a temperature of 160.degree. C. and at a pressure
of 2M Pa.
[0335] The recession structure was formed in the coverlay by the
above-mentioned process, and the same examination was performed.
However, in the ink jet method, since the extending wiring line in
the recession structure was not covered, an unstable oxidation
reaction occurred in the gold-copper alloy. That is, it was
important to draw the extending wiring line immediately below the
electrode. However, in this case, oxygen plasma processing was
performed with an output of 300 W for one minute, or UV and ozone
processing was performed for 50 minutes to improve wettability, and
a predetermined amount of material (0.004 .mu.L in a .phi.1.5
electrode) was applied by a micropipette technique to cover the
wiring line in the recession structure. However, in this case,
production efficiency was reduced. When the oxygen plasma
processing and the UV and ozone processing were performed, the
wettability of a test solution as well as the wettability of a base
material was improved. When the liquid crystal polymer was used, a
mysterious phenomenon in which a current signal was not output even
though the voltage was swept occurred. In this case, when the
surface was wetted by pure water before it was immersed in the test
solution, a signal was output. Therefore, the inventor considered
that the phenomenon occurred because surface energy was low and
water-repellency was high. After the process, it was possible to
measure the output of the current signal even though the surface
was directly immersed in the test solution. As described above,
after the wiring line below the recession structure was covered, it
was possible to form the carbon including layer on the electrode
and the coverlay so as to be insulated from the surface of the
coverlay using an ink jet method.
[0336] According to the invention, it was possible to construct an
analysis sequence shown in FIG. 40. The invention can be applied to
metal ions, such as cadmium, or a related chemical species as well
as monovalent copper. The invention can be used to analyze, for
example, an etchant, tap water, soil, and the contamination of a
food and a plant, such as a rice plant or vegetable, from soil, in
addition to the plating solution.
* * * * *
References