JP2019090709A - Electrode structure - Google Patents

Abstract

To eliminate an unexpected change (noise) of a jig, etc., that handles and holds a sample for detecting a detection electrode that constitutes a detection system as much as possible and maintains and improves the limit of detection sensitivity itself as well in a sensor and an evaluation analyzer using a valve metal as an electrode material.SOLUTION: Provided is an electrode structure equipped with a substrate and an electrode composed of a valve metal that is formed on at least a portion of the substrate, in which a protective film composed of an amorphous carbon film or a protective film composed of a dry thin film including one or more of the oxide, nitride, carbide, oxynitride, carbonate, carbonitride and carboxynitride layers of silicon or metal is formed on the electrode, the protective film having a film thickness of more than 10 nm and less than 200 nm. Alternatively, a water-repellent and/or water-and-oil repellent thin-film layer is further provided on the protective film composed of the amorphous carbon film or the protective film composed of the dry thin film.SELECTED DRAWING: None

Description

  The present invention relates to an electrode structure used in a sensor or an analysis and analysis device, and more particularly to an electrode structure for stabilizing and improving measurement accuracy in a sensor or an analysis and analysis device for liquid or gas.

  Sensors and evaluation analyzers have been used in a laboratory or operating room in a research facility or in a mildly specified indoor environment such as a clean room with constant temperature and humidity. Also, it is assumed that such environment is used. It was designed.

  In recent years, when sensors and evaluation and analysis devices are converted to microdevices and occupy a part of the configuration mechanism of ITO (Internet on Tools), detection devices for automatic unmanned operation in automobiles and growth of crops in outdoor farms It will be carried out outdoors in a harsh and changing environment, such as situation monitoring, water monitoring in hydroponic cultivation plants, accidents in emergency critical care, simple quick measurement and diagnosis at disaster sites etc. Ensuring resistance to UV rays, corrosive rain, exposed corrosive polluting atmospheres and exhaust gases, and atmospheres containing salt of seawater, etc. Also, it is short every moment in a wide range from -40 ° C to near 80 ° C It has been designed on the premise of use in dry environment, such as structural fatigue such as peeling and deformation of components due to heat cycles in the external environment repeated in time. In the sensor electrode, it is necessary to provide resistance design equivalent to that of the electrode used in wet, such as measures against corrosive condensation generated by heat cycles and measures against gas, etc. It has become an important or major function for maintenance and improvement.

  In addition, while the sensor and evaluation analysis device are required to be smaller and lighter for portable use, for example, in the medical field, in the case of collecting a sample from a patient with a disease etc., to ease the pain of the patient and maintain the biological function, There is a need for higher detection capabilities for samples collected in small quantities at lower cost.

  Usually, as a material of a detection electrode such as a sensor, an evaluation analyzer, etc., one made of a noble metal such as gold or platinum is used. Noble metals are excellent in corrosion resistance and conductivity, and when used as electrodes for sensing, they do not cause changes in electrical conductivity due to corrosion from the sample or the environment in which they are used, enabling stable and accurate measurement. .

On the other hand, “valve metals” represented by Al, Ti, Ni, Cr, etc. are base metals, but they naturally form passive layers derived from thin base materials such as oxide films on their surface like noble metals. It is a metal having corrosion resistance, and from the viewpoint of the stability of the electrical capacity provided by the passive layer and the cost reduction, it may be extremely effective to use the noble metal in the electrode of an electronic component or the like in place of the noble metal.
However, in sensors and evaluation analyzers, etc., “changes” that occur or occur when a sample is introduced into a detection / measurement system, such as changes in current, voltage, electrical resistance, electrical capacity, etc. The ability to accurately detect “quantity” with high sensitivity is extremely important, and in particular it is necessary to detect minute changes (quantity) correctly. It is a rule not to select a "valve metal" with a dynamic film, and as described above, an electrode made of a noble metal having excellent corrosion resistance and low electrical resistance is usually used.

  Furthermore, in a sensor, an evaluation analyzer, etc., in order to improve the detection sensitivity, expansion of a unit surface area of the electrode for increasing the contact area of the electrode with the sample of the sample, that is, miniaturization of the electrode is performed. For example, in a comb electrode, the width of the comb teeth (usually the conductive electrode) and the distance between the comb teeth (usually the electrically insulating portion where the substrate surface of the insulating electrode is exposed) are as narrow as possible. (Fine, high definition) A large number of conductive parts and insulating parts are arranged in a certain area to narrowly adjoin between the electrodes such as between the anode electrode and the cathode electrode, and to make physical contact with the sample Improvement by the modeling and structural devices, such as increasing the contact area of, and improving the sensitivity of detection and analysis, etc. is in progress.

JP, 2016-171168, A International Publication No. 2014/163038 International Publication No. 2016/056466

As described above, in the detection sensor or evaluation analyzer, the “change” that occurs when the sample sample is introduced into the detection / measurement system, for example, the change “amount of current, voltage, electric resistance value, electric capacity, etc. "The ability to accurately detect with high sensitivity is extremely important, and in order to detect the minute changes (amounts) correctly, the members that constitute the detection system, such as the detection It is necessary to eliminate the unexpected change (noise) of the jig etc. held as much as possible, and to improve the limit of detection itself in parallel.
On the other hand, as described above, in the sensor for detection and the evaluation analysis device, cost reduction is required, and replacing the noble metal with the valve metal which is the above-mentioned base metal is for cost reduction. It is expected as 1 method.
However, there are various problems to be solved with respect to the use of valve metal in the sensor for detection and the electrode in the evaluation analyzer as follows.

(Enhanced corrosion resistance including gas barrier properties to the valve metal surface passivation layer)
As an example of a valve metal (valve metal), a passivation layer made of aluminum oxide and / or aluminum hydroxide is made of titanium oxide in the surface layer of aluminum or aluminum alloy, and a surface layer of titanium or titanium alloy is made of titanium oxide. Passivation layer is nickel or nickel alloy surface layer nickel oxide, passivation layer consisting of nickel oxide, chromium or chromium alloy surface layer, and surface layer of chromium rich stainless steel alloy surface Passivation layers made of oxide are respectively formed. These passivation layers are naturally formed on metal by an oxygen source (O ₂ in air, O ₂ in water, O ₂ and the like) to be a protective layer, but the passivation layer to be formed is 1 There may be a very small thickness of several tens of nm, and if the passive layer alone is used, the ingress gas from the external environment where the electrode is present, various gases generated at the time of detection reaction, such as water constituting buffer solution, environmental Anti-hydrogen embrittlement of the electrode due to hydrogen generated carelessly from the temperature cycle and electrolyzed by dew condensation water etc. adhering to the electrode surface, gas such as water vapor and oxygen, corrosive specimen itself, solution containing the specimen Maintenance and improvement of durability such as corrosion resistance against (solvent) or corrosive atmosphere, etc. and sensitivity are not sufficient.

  For example, an electrochemical sensor that performs sensing by dropping a buffer solution or the like containing a sample onto the comb-like electrode to perform sensing is such that a buffer solution consisting of an aqueous solution or a sample in the solution chemically reacts and ionizes and flows to the electrode It measures and detects electricity (current), applied voltage, change in electric capacity, etc. At the time of the reaction, the electrode is weakened by hydrogen generated by electrolysis of a solvent such as water of the sample. It may occur (hydrogen embrittlement) and may corrode by solutions such as water. Furthermore, if the hydrogen gas which is very small in diameter and easily diffuses into the metal diffuses into the inside of the electrode and is ionized, it may occur as noise of the measurement current.

(Ensuring adhesion of protective film to valve metal surface passivation layer)
In addition, a comb-shaped electrode or the like made of a valve metal such as aluminum is an upper layer of an insulating substrate (film, material) such as rubber, resin, glass epoxy, glass, ceramic, insulating film formed on semiconductor surface such as Si. In many cases, patterning is partially formed. For example, in order to ensure the corrosion resistance of the valve metal, there is a method of applying a film made of a water repellent material and a water and oil repellent material on the surface layer to form a water and oil repellent resin thin film. The surface layer of the dynamic layer has poor reactivity and bondability, and is formed on a resin substrate, etc., which is an insulating substrate, including a water- and oil-repellent resin thin film made of a coupling agent with high bondability. In some cases, the water and oil repellent resin thin film coupling agent layer peels off from the substrate or the electrode and becomes a contamination source (contamination source) without improving the corrosion resistance of the electrode.

(Ensuring conductivity and detection sensitivity of valve metal with passive layer)
Thus, while the passive layer naturally formed on the valve metal contributes to the corrosion resistance of the electrode, the electrical resistance is large, and it is weak if the protective layer additionally formed on the passive layer is further insulating. On the contrary, it is better not to be present for a sensor electrode or the like that senses a large current.
Furthermore, as a matter of course, with regard to the detection electrode and the jig to be used for the detection device, such as cost increase and processing limit derived from the complicated structure such as handling the specimen sample with a complicated modeling structure and contacting the electrode A problem arises.

In order to improve the corrosion resistance, it is conceivable to thicken the anodic oxide film (passive layer) formed on aluminum (Al) or the like. Moreover, after forming an anodic oxide film on a base material as a method of providing corrosion resistance to Al metal, a layered product in which an amorphous carbon film is further formed on the anodic oxide film is also developed.
However, the anodized film has high insulating properties and is not suitable for electrode applications requiring conductivity to a certain degree or more. Also, control of the film thickness of the anodic oxide film becomes extremely difficult. Furthermore, there is also a point to be improved such as poor adhesion with the amorphous carbon film.

Further, according to Patent Document 1, in the electrochemical cell in which the positive electrode can and the electrode are conducted, by forming a conductive protective film on the surface of the positive electrode can in contact with the electrolytic solution, corrosion resistance to the electrolytic solution can be secured. A conductive DLC (diamond like carbon) film is described as an example of the protective film.
However, the formation of conductive DLC requires the use of more toxic, explosive, dangerous and more expensive source gases such as B (boron) and As (arsenic), or another method In this case, it is necessary to apply a positive voltage of reverse bias to the DLC film in the vacuum apparatus after forming the insulating DLC film once or while forming the insulating film, and to irradiate the DLC film with high energy divergence electrons etc. There is a problem that the cost increases including the device.

  Furthermore, in these prior arts, in order to perform electrochemical detection, dew condensation water to the electrode which is used by flowing electricity in a solution such as water, and also carelessly generated from the temperature cycle of the use environment, etc. In fact, protection of the electrode from hydrogen gas generated by the electrolysis of water and contaminants contained in the water from the environment and generated (generated), prevention of noise source generation, etc. have not been studied. is there.

  The present invention has been made in view of the above-described present situation, and in a sensor or evaluation analysis apparatus using a valve metal as an electrode material, a member which solves the above-mentioned problems in the prior art and constitutes a detection system For example, an object of the present invention is to eliminate, as much as possible, unexpected changes (noises) of a detection electrode, a jig for handling and holding a sample for detection, etc., and maintain and improve the limit of detection sensitivity itself in parallel.

  As a result of investigations to achieve the above object, the inventor of the present invention has found that, in an electrode structure provided with a substrate and an electrode made of a valve metal formed on at least a part of the substrate, a film thickness is formed on the electrode A protective film consisting of an amorphous carbon film having a thickness of more than 10 nm and less than 200 nm, or any of silicon or metal oxide, nitride, carbide, oxynitride, carbide, carbonitride or carbonitride layer By forming a protective film consisting of a dry thin film containing one or more, or further on the protective film consisting of the amorphous carbon film or on the protective film consisting of the dry thin film It has been found that by providing an oily thin film layer, the problems in the prior art can be solved.

The present invention has been completed based on these findings, and provides the following invention.
[1] An electrode comprising a substrate, a valve metal formed on at least a part of the substrate, and a protective layer having a thickness of more than 10 nm and less than 200 nm formed on the electrode,
An electrode structure for a sensor or an evaluation analyzer, wherein the protective layer comprises an amorphous carbon film.
[2] An electrode comprising a substrate, a valve metal formed on at least a part of the substrate, and a protective layer having a thickness of more than 10 nm and less than 200 nm formed by a dry process on the electrode,
A sensor characterized in that the protective layer is a thin film containing any one or more of an oxide, a nitride, a carbide, an oxynitride, a carbonitride, a carbonitride or a carbonitride layer of silicon or metal. Electrode structure for use with or for an analytical analysis device.
[3] An electrode structure for a sensor or an evaluation analysis device according to [1] or [2], comprising a water-repellent and / or water- and oil-repellent thin film layer on the protective layer. .
[4] The electrode structure for a sensor or an evaluation analysis device according to [3], wherein the thin film layer is a resin layer composed of a fluorine-containing coupling agent having a film thickness of less than 50 nm.
[5] An electrode structure for a sensor or an evaluation analysis device according to any one of [1] to [4], wherein the valve metal has a passivation layer on the surface thereof.
[6] An electrode assembly for a sensor or an evaluation analysis device according to any one of [1] to [5], wherein the electrical resistance under a load voltage of 0.39 v is less than 0.45 Ω.
[7] The outermost surface of the substrate on which the electrode is not formed and / or the outermost surface of the portion on which the electrode is formed is characterized by comprising a surface having different surface wettability with water and / or oil. An electrode assembly for a sensor or an evaluation analysis device according to any one of [1] to [6].
[8] The sensor according to any one of [1] to [7], wherein the protective film conforms to the standard (such as Ministry of Health and Welfare Notification No. 370 of the Ministry of Health and Welfare, 1979) of food, additives, etc. Electrode structure for the device for the purpose or evaluation analysis.
[9] The electrode structure for a sensor or evaluation analysis according to any one of [1] to [8], wherein the protective film has a hydrogen gas permeation preventing property larger than that of the base material.
[10] The electrode structure for a sensor or evaluation analysis according to any one of [1] to [9], wherein the dielectric constant of the protective film is less than 50.

  According to the present invention, a detection electrode using an electrode made of a valve metal, in particular, a thin film having a thickness of several hundred nm or less on an insulating base material such as resin or glass which is difficult to adhere to, adhesion to a substrate In a fine detection electrode, which has a small area and on the other hand a surface area (peripheral pattern and peripheral extension of the electrode) often formed large on the other hand, adhesion to the electrode particularly in a corrosive liquid is secured To improve the weather resistance and corrosion resistance, in particular, to prevent deterioration to hydrogen, water vapor or oxygen present in the detection environment, while maintaining the necessary minimum functions such as securing the required conductivity, etc. be able to.

A photograph of the surface sprayed with pure water in order to confirm the patterning property of the liquid by surface wettability control The figure which shows the result of the friction wear test about a comparative example The figure which shows the result of the friction wear test about an example

  In the present invention, in the detection electrode using an electrode made of a valve metal, in particular, the adhesion between the surface of the valve metal electrode and the passivation layer is secured, and the conductivity already decreased by the passivation layer of the surface of the valve metal electrode To improve corrosion resistance and corrosion resistance while maintaining the necessary minimum functions such as securing conductivity required as a detection electrode, in addition, hydrogen, water vapor or the like which are generated particularly at the time of detection and further present in the detection environment The following embodiments are preferably employed to prevent the deterioration of oxygen.

In the first embodiment of the present invention, the protective film made of amorphous carbon formed by the dry process can ensure close contact with the passivation layer of the valve metal, and the conductivity of the electrode to a certain extent It forms as a protective film in less than 200 nm which is the thickness which does not impair above.
Also, in the second embodiment of the present invention, the protective film is a thin film formed by a dry process, and the adhesion with the passivation layer of the valve metal is also good, and the film density is very high. It is made of one or more materials of oxides, nitrides, carbides, oxynitrides, carbides, carbonitrides, carbonitrides, and the like of metals such as silicon, titanium, aluminum, and zirconium, which have water vapor barrier properties and the like. The film thickness is less than 200 nm.
Furthermore, in the third embodiment of the present invention, corrosion is caused by adsorbing or inducing a polar substance that corrodes an electrode such as water on pin fall of a protective film formed by a dry process for the purpose of weather resistance such as gas barrier. To provide a water-repellent or water- and oil-repellent film on the protective film so that
The details will be described in order below.

In order to ensure (improve) the corrosion resistance and corrosion resistance, the formation of a protective film by a dry process is effective.
This is because, when a protective film is formed by a wet process, the electrode having a complex fine structure is easily affected by gravity, surface tension, and surface wettability of a substrate to be coated when the liquid protective film is applied. The liquid protective film flows in the direction of gravity in the part with fine and complicated unevenness such as detection electrode, for example, the film is thick in the concave part, the film is thin in the convex apex, etc. It is because it may be difficult to form. In addition, except for those having a film thickness of several tens of nanometers such as a coupling agent, it may be difficult to apply the liquid protective film thinly and uniformly so as not to disperse the electrical resistance.

  Furthermore, the liquid protective film generally has a low film density and generally can not be expected to have gas barrier properties. For example, the wet film which improves the gas barrier property includes a sol-gel method film using metal alkoxide etc. as a starting material, but in order to obtain high film density and gas barrier property, heating after application is over 500 ° C and nearly 1000 ° C. Therefore, there is a concern that the electrode to be protected is oxidized, deformed and destroyed, and it becomes impossible to use an electrode or jig based on a resin or the like.

On the other hand, protective film by dry process, especially hard protective film, is effective because it secures the gas barrier property derived from its high film density, and it becomes possible to form a substrate with a thin film that is not easily affected by gravity and uniform film thickness. However, conversely, there is a problem of the base material adhesion decrease due to the internal (residual) stress caused by the high film density, especially the adhesion to the valve metal electrode surface layer which is worse in adhesion than the usual base material of the present application. It is necessary to take action to secure it.
The protective film by the conventional dry process is mostly used for wear resistance, high sliding, seizure resistance, corrosion resistance, etc., its film density is high, residual internal stress is strong, its film thickness is 500 nm or more, and in some cases It is often a thick film up to about 3 μm. Furthermore, the electrical conductivity and the like are hardly considered or not emphasized.
In addition, when forming the protective film as described above on the valve metal, the passivation layer on the surface layer has poor adhesion, so sputtering pretreatment with an inert gas plasma such as Ar (for example, sputtering pretreatment is performed for 5 minutes or more It is common knowledge of those skilled in the art to sufficiently remove the passive layer of the valve metal to ensure close contact.

Furthermore, when a protective film having a large internal residual stress formed in the dry process is formed on the valve metal, the electrode itself made of (received) the residual stress is the insulation on which the valve metal electrode is formed. It is also easy to stress-release from the substrate.
For example, the stretchability of a dry film consisting of Si _x O _y , Al _x O _y , and Ti _x O _y is only about 1%, and when a metal electrode with large ductility is stretched, its followability is poor and cracks easily occur. It causes peeling from the base material and gas leakage (ingress of gas from the outside).
The coefficient of thermal expansion of the dry film consisting of Si _x O _y , Al _x O _y and Ti _x O _y is only about one digit × 10 ⁶ cm · ° C., but the valve metal Al is 23 × 10 ⁶ cm · ° C. approximately, 13 × 10 6 ^cm · ℃ about a 1 digit increase in Ni, heat cycles at ambient repeated every moment a short and wide range of minus 40 ° C. to 80 ° C. near, dripping of the test sample to detect In some cases, it is likely to cause peeling due to a temperature change or the like associated with the above.

For example, well-known electroless Ni-P plating (film thickness approximately 200 nm), electrolytic copper plating (film thickness approximately 10 μm), electrolytic Ni plating (film thickness approximately 3 μm), electrolytic chromium plating (film thickness approximately 3 μm) on resin substrates such as PC / ABS A sample with a thickness of approximately 700 nm and an amorphous carbon curtain film with a Vickers hardness of approximately Hv 1700, which are plated in layers in order of film thickness of approximately 100 nm) Thermal shock test (performed by using a thermal test equipment: TSA-200S-W / 20) to prepare a carbon dioxide film having a thickness of approximately 200 nm and perform thermal thermal cycling for 20 hours at -30 ° C for 3 hours and 60 ° C for 3 hours As a result of performing Tabei Espec), in the case of forming an amorphous carbon film having a thickness of 700 nm, swelling (peeling) from the substrate of the electroless Ni-P plating layer can be confirmed, and a thick film is formed on the uppermost layer Formed by The internal stress of the amorphous carbon film can be observed or how to inhibit substrate adhesion of the electroless Ni-P plating layer itself.
The amorphous carbon film has a linear expansion coefficient of about 1 digit × 10 ⁶ cm · ° C. and a large stretchability of about 3% and is flexible in various hard films, and is suitable as a protective film of the electrode structure of the present invention However, if it is formed as a thick film, the above-mentioned peeling problem may occur.

  Taking the above into consideration, in the first embodiment of the present invention, the protective film made of amorphous carbon formed by the dry process can ensure the adhesion with the electrode (particularly the passivation layer of the valve metal). Therefore, the protective film is formed with a thickness of less than 200 nm so as not to impair the conductivity of the electrode by a certain degree or more.

  The inventors of the present invention found that the amorphous carbon film formed by the dry process is likely to form pin fall like the various films described above, but has the same surface component as the oil and wettability near the hydrophobic layer, Furthermore, since it had an extremely inactive surface layer with very few polar functional groups, it was confirmed that it was difficult to adsorb and induce polar substances that would corrode electrodes such as water on pin fall and it was difficult to cause corrosion (see Examples). In addition, it was also verified that the amorphous carbon film is excellent in hydrogen gas permeation prevention as well as water vapor permeation prevention and oxygen permeation prevention (see Examples).

In addition, an electrode such as a sensor is often formed on a resin substrate such as an insulating resin substrate due to its economy and productivity. For example, a silicon oxide film or a dry thin film containing Si (for example, an amorphous carbon film containing Si) is excellent in adhesion to a metal material (passive layer) of an electrode, etc., but adhesion to a resin substrate portion is Si. The carbon film (amorphous carbon film) which does not contain is better in adhesion.
Therefore, when the amorphous carbon film is simultaneously formed on the electrode and the base material, it is possible to suppress the generation of contamination sources such as peeling of the amorphous carbon film from the resin substrate (see Examples).

As described above, thin films formed by dry processes such as amorphous carbon films generally have high film density, and as a trade-off for having gas barrier properties, internal residual stress is large and the inertness of valve metals makes it difficult to obtain adhesion. The adhesion with the passivation layer may be poor, and the possibility of stress separation is increased.
In such a case, various metal elements such as Si, Ti, Al, and Zr are added to the amorphous carbon film to reduce the stress of the film of the amorphous carbon film and improve the adhesion to the substrate. makes a method (in particular a method for adding the same element as the element contained in the base material), a small insulating film having a relatively internal stress _{Si x O y, Al x O} y, Ti x O y, Zr x O y , etc. It is possible to substitute the oxide film, the nitride film, the oxynitride film, or the dry thin film obtained by mixing carbon with the film described above.

As described above, as the second embodiment, the protective film according to the embodiment of the present invention is a thin film formed by a dry process, and the adhesion to the electrode made of valve metal is good, and the film density is high. Materials of one or more of oxygen gas, oxide of metal such as silicon, titanium, aluminum, zirconium, etc. having water vapor barrier property, nitride, carbide, oxynitride, carbonate, carbonitride, carbonate and nitride It is effective to form a protective film having a film thickness of less than 200 nm.
For example, an oxide film (silica film) of silicon formed by a dry process, or an oxide film of silicon containing carbon for improving adhesion to a base material, etc. are transparent hard of solar cell back sheet, food packaging base material, and electronic parts It is known as a gas barrier protective film.

  However, silicon or metal oxides, nitrides, carbides, oxynitrides, carbonates, carbonitrides, carbonitrides, silicon nitrides, particularly silicon oxide films and carbons frequently used in gas barrier films, formed by dry process The silicon oxide film, titanium oxide film, amorphous carbon film containing Si, Ti, Al, Zn, and polar elements such as oxygen and nitrogen, etc. And polar functional groups, such as silanol groups, carbonyl groups, carboxyl groups, etc., which are easily produced, and accompanying these to the surface layer, the wettability of the surface becomes hydrophilic, and the migration to the hydrophilic / lipophilic direction Do.

  The width and interval of the wiring of the comb electrode recently appear narrower than 10 μm width, and when the electrode part has a fine concavo-convex structure such as “convex up”, the comb electrode part is derived from the concavo-convex structure formed by the electrode as a whole In some cases, the water repellency and the structure oil repellency may be exhibited carelessly, and the liquid sample may not be sufficiently wetted and spread on the electrode portion (insulation portion). That is, there is a case where it becomes impossible to function as a detection electrode. In this case, a liquid sample is formed by forming a film that exhibits the structure water repellency and the structure oil repellency of the second embodiment, thereby making the electrode, the insulating portion, or both of them hydrophilic or lipophilic. It can also be wet and spread to the position necessary for sufficient measurement. Such a hydrophilic and hydrophilic / lipophilic comb electrode can also save time and labor for laying a glass cover or the like on the electrode and the dropped sample after dropping the droplet sample onto the electrode portion.

  On the other hand, the structural water-repellent, structurally oil-repellent coating of this second embodiment has a polar functional group on the surface thereof, thereby adsorbing a polar substance that corrodes an electrode such as water (through) on the pin-fall. In addition, there is a concern that the electrode surface may be easily guided through the pin fall, which may cause corrosion of the electrode, so that it is not suitable for long-time measurement and the like.

Furthermore, a polar functional group such as a silicon oxide or metal oxide, nitride, carbide, oxynitride, carbonate, carbonitride, carbonitride or the like of the second embodiment is naturally generated (formed) on the surface thereof. Easy (including the film formed by the dry process) UV light such as sunlight in the outdoors, condensation water generated from the heat cycle (especially containing corrosive and polar components) and oxidizing atmosphere such as water of the specimen When exposed to the inside, the formation of polar functional groups is further promoted, and the surface layer is easily transferred to the surface on the hydrophilic side.
For example, a sample 1 in which an amorphous carbon film composed of hydrogen and carbon is formed on a stainless steel plate (SUS304 2B base material) each having a thickness of about 40 nm by a known plasma CVD process, and amorphous containing silicon Of a porous carbon film with oxygen plasma to form a large amount of polar silanol groups (Si-OH groups) on the surface layer, and a known layer 2 on the surface of the sample 2 to form a film by dehydration condensation reaction Two days after additionally forming a water- and oil-repellent layer consisting of a fluorine-containing coupling agent (Fluorosurf FG-5010Z130-0.2, manufactured by Fluorotechnology, Inc.) in a thickness of approximately 20 nm by a spray method, IPA (isopropyl alcohol) The sample 3 was cleaned for 5 minutes with an ultrasonic cleaning tank filled with the sample, and the samples 1, 2 and 3 were subjected to a constant temperature and humidity control bath for high temperature high humidity test (test equipment: PR-2GP / Taba Frictional abrasion test (apparatus: Tribogear HHS-2000 Shinto Scientific Co., Ltd., constant load reciprocating measurement load: 50 g, indenter: SUJ2 φ 2.) When 0 mm, 50 double-stroke friction) is performed, sample 1 and sample 3 do not show a large difference in deterioration of the friction coefficient before and after being added to the high temperature and high humidity tank, but polar silanol group (Si-OH group) The maximum coefficient of friction of the large amount of hydrophilized sample 2 is increased from the maximum value 0.5 μ (mu) of the same sample before being added to the high temperature and high humidity tank to 1.5 μ which is three times higher It is possible to confirm the deterioration of itself and the adhesion of the substrate. Stainless steel is a substrate that is less likely to be corroded than Al etc., and deterioration of the friction coefficient does not cause deterioration of the sample due to the corrosion of the substrate, and deterioration of the sample itself against high temperature and high humidity environment can be assumed. We can confirm the difference in durability performance in

From this fact, it is possible to select the substrate 1 with a passivation layer which is relatively resistant to corrosion among the valve metals, particularly Ti, Ni, Cr, samples 1 and 3 for all valve metals such as Al with anodic oxidation and strengthening the passivation layer. The effectiveness of the protective film in the form of high temperature and high humidity has been confirmed.
However, the form of sample 3 is inferior to the form of sample 2 or sample 1 in terms of conductivity deterioration since a fluorine resin film having an extremely large insulating property is additionally formed as compared with the protective layer according to the present invention. Become
In addition, after the water is contained in the wettable film on the hydrophilic side such as the sample 2, for example, in the pin fall of the film, the film is degraded by volumetric expansion of the water when the water freezes in the environment Is easily predictable.

Therefore, in the third embodiment of the present invention, oxides of silicon or metal, nitrides, carbides, oxynitrides, carbonates, carbonitrides, carbonates, carbonates, etc. formed by a dry process for the purpose of heat resistance such as gas barrier. Water-repellent or water- and oil-repellent coating is further applied to the protective film so that corrosion does not occur by adsorbing or inducing a polar substance that corrodes the electrode, such as water, to pinfall of nitride. It is
A large number of polar functional groups such as silanol groups, carbonyl groups and carboxyl groups are generated on the surface of a film formed by a dry process, which is an embodiment of the present invention A water-repellent or water- and oil-repellent coating made of a coupling agent or the like bonded to the above easily adheres strongly.

Even though the water- and oil-repellent coating is a thin film, it is typically represented by a fluorine resin (layer) made of a fluorine-containing coupling agent or the like, and has a high insulation property with a volume electrical resistivity approaching ^1015-20 Ω · cm. There are concerns that many are used for insulation applications and there is a concern that the application to the conductive electrode is not appropriate. However, the present inventor is composed of a fluorine resin (layer) made of a fluorine-containing coupling agent or the like. It was also verified that the present insulation film having a thickness of at least 50 nm can be used for electric electrode applications.
A composite layer having a film thickness of at least 50 nm less than that of the above-mentioned protective film excellent in corrosion resistance consisting of an insulating thin film having a film thickness of less than 200 nm by dry process and a fluorine resin (layer) The protective film is formed to a thickness that does not impair the conductivity to a certain degree or more.

The detection electrode according to the present invention is expected to be used in solution, which is a sample, or in contact with a liquid such as a solution or careless condensed water, so that the film component is eluted and detected in the liquid. It is important not to affect the
Therefore, it is preferable that the formation of a water-repellent or water- and oil-repellent film on the protective film in the third embodiment of the present invention is also performed by a dry process such as a resistance heating method or a vacuum plasma method.
For example, when a workpiece is dipped in a fluorine-containing coupling agent solution to form a water-repellent or water- and oil-repellent coating, unreacted residues of a high concentration of the fluorine-containing coupling agent solution are a substrate or a primer layer. When entering a detection thin film according to one embodiment, or entering a thick thin film of the dry thin film, etc., and accumulating in a concave part of the uneven structure of the electrode by gravity, etc. when using the detection electrode It is very important to prevent the elution and diffusion of the fluorine-containing coupling agent (including the component) in the solution, as well as the conductivity control of the fluorine-containing coupling agent film which is also insulating.

The sample of the detection electrode according to the present invention may be a biological sample, a food, a beverage, a medicine, etc. Therefore, it is also important to confirm that there is no problem in the elution from the electrode and the elution component as described above. .
For example, the amorphous carbon film containing silicon is plasma irradiated with oxygen on a stainless steel plate (SUS304 2B base material) in a thickness of about 40 nm by a known plasma CVD process, and polar silanol groups (Si Water- and oil-repellent layer consisting of a well-known fluorine-containing coupling agent (Fluorosurf FG-5010Z130-0.2 from Florotechnics Ltd.) which forms OH group in a large amount on the surface layer and forms a film by dehydration condensation reaction with the silanol group A sample according to an embodiment of the present invention was prepared by washing for 35 minutes in an ultrasonic cleaning tank filled with IPA (isopropyl alcohol) two days after additionally forming an outermost layer with a thickness of approximately 20 nm by a spray method, food, Additives, etc. Standards standards (3rd D 2 100 ° C or less of Ministry of Health and Welfare Notification No. 370, 1959)) Appliances and containers and packaging standards test (synthetic resin) A general standard dissolution test (conducted by Japan Food Research Laboratories, Inc.) was conducted to confirm that the sample of the present invention conforms to the standard (within limits).

A further preferred embodiment of the present invention is to form the dry film in a process that does not damage the passivation layer on the surface of the valve metal.
The passivation layer on the valve metal surface layer is difficult to form an electric double layer on the electrode surface layer, and the stability of the electrical capacity of the passivation layer itself is high. Therefore, it is extremely important for the stability and reproducibility of detection by the detection electrode. It can be advantageous or meaningful.
In addition, since the protective film formed of a dry thin film on the passivation layer of the valve metal surface layer is also difficult to form an electric double layer, the electrode also contributes to the stabilization.
The electric double layer has an important meaning in the field such as electrochemistry because it greatly affects the behavior of ions in the vicinity of the electrode. In addition, the corrosion resistance of the electrode becomes a very important performance for the measurement system because the electric double layer capacity rises and changes as the surface roughness of the electrode increases and the surface area of the electrode increases due to corrosion and dissolution of the electrode.

  On the other hand, the passivation layer on the valve metal surface layer may be as thin as 1 nm to several tens of nm in thickness. For example, before forming a dry thin film in various vacuum plasma film forming apparatuses, it is usually impossible to The surface layer of the film formation target substrate is sputtered by plasmatizing the active gas and fluorine gas, etc., and removal of the passivation layer on the surface layer of the substrate to be formed and cleaning of foreign matter are carried out. Therefore, this cleaning can not be performed, or the processing can be performed with less energy for a short time as compared with the prior art.

  Hereinafter, the material etc. which comprise the electrode structure concerning embodiment of this invention are demonstrated in order.

(Base material)
The substrate is not particularly limited, and is made of various metals, resins, or glasses, semiconductors, ceramics, cellulose or mixtures of various materials, composites, laminates and the like. In some cases, it is preferable to be an insulator.
Furthermore, the roughness of the surface layer of the substrate is appropriately adjusted according to the required function, for example, the wettability modification of the surface, physical treatment such as blasting, lapping, peening, etc., chemical treatment such as electropolishing or chemical solution etching It may be appropriately adjusted by (electrochemical) treatment, plasma treatment, UV treatment or the like.

(electrode)
Examples of the valve metal used as the electrode material of the present invention include aluminum, chromium, titanium, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, antimony, nickel and the like. Furthermore, various alloys or composites containing any one or more of the valve metals can also be used. Furthermore, it may be an amorphous metal which does not take the form of a metal crystal.
Further, the processing and forming methods of the electrode are not particularly limited, and can be performed by various methods such as known photolithography method, plating method, plating electroforming method, press processing, cutting processing, laser processing, etc. and is not particularly limited. .
Furthermore, the roughness of the surface layer of the electrode can be appropriately polished according to the required function such as wettability modification of the surface, physical processing such as blasting, lapping, peening etc., chemical processing such as electropolishing or chemical solution etching It may be appropriately adjusted by chemical treatment, plasma treatment, UV treatment or the like.

  The electrode containing the valve metal used as the electrode material of the present invention may have a passive layer which the valve metal spontaneously forms on the surface thereof in the atmosphere, and the passive layer is positively added to the surface of the valve metal. It may be formed. For example, the valve metal may be disposed in an oxygen atmosphere in which oxygen gas, ions, radicals and the like are present, and the passive layer of the valve metal may be strengthened or repaired. In addition, it can be disposed in an oxidizing atmosphere such as water, and it is also possible to form a passivation layer on the surface layer of the valve metal as appropriate, such as performing electrolytic polishing. In addition, it is possible not to deviate from the spirit of the present invention that the valve metal base is subjected to a nitriding treatment, an annealing treatment is performed, the contained hydrogen and the like are discharged, and another treatment is given to the valve metal. It can be carried out.

  The valve metal used as the electrode material of the present invention also includes, for example, the valve metal material formed in a dry process in an oxygen-free atmosphere such as a vacuum device on the substrate. For example, there is a valve metal electrode such as an Al electrode formed by sputtering from an Al target in a vacuum (in an oxygen-free atmosphere). After the sputtering Al electrode is formed in the vacuum (oxygen-free) atmosphere, the protective film is continuously formed on the surface layer by the dry process according to the present invention without breaking the vacuum (without exposure to the oxygen atmosphere). It is also possible. However, even if the protective film by the dry process according to the present invention is continuously formed in a vacuum (in an oxygen-free atmosphere) as described above, the protective film of the present invention necessarily has pinfall that leads to a fine substrate. Since the passivation layer is formed at the stage where the pin fall is later exposed to the open air, it has the features and characteristics of the valve metal of the present invention and can be the subject of the present application.

The valve metal according to the present invention, and the passive layer of the valve metal may be formed on the surface layer of another base material, or may be made of a plurality of valve metals without departing from the scope of the present invention. I do not mind.

(Preprocessing)
A pretreatment such as cleaning of a valve metal substrate, which is performed before forming a protective layer made of a thin film by a dry process according to the present invention, will be described.
In general, sputtering (cleaning) of the surface layer of the treated substrate with an inert gas such as Ar or other etching gas in the case of forming a thin film by a dry process on a substrate is a thin film formed on the substrate by a dry process Removes foreign substances from the substrate, prevents plasma charge buildup due to oxides and oxide films in advance, raises the substrate temperature (reaction temperature) to activate the substrate, and brings the dry thin film into close contact with the substrate. It is an important process commonly performed by those skilled in the art as the most important process for forming a material.
However, since the passivation layer formed on the surface layer of the valve metal according to the present invention is very thin, the sputtering (cleaning) is normally performed by the inert gas such as Ar by the dry process or other etching gas. The passivation layer of the valve metal may be removed, annihilated or partially destroyed.
For example, in a vacuum plasma process, the implantation depth of Ar ions or the like sufficiently biased by a DC high-voltage pulse or the like from the surface layer of the substrate to the inside of the substrate may exceed 30 nm. If the Ar ion is accelerated and implanted into the substrate at an applied voltage exceeding 3000 volts and the treatment is carried out for about 10 minutes in the following state, the passive layer as thin as several nm may be removed cleanly.
Therefore, it may be best not to carry out Ar plasma cleaning for at most approximately less than 5 minutes, preferably less than 3 minutes, or for clean conditions with no foreign material on the substrate.

(Protective layer)
The formation of a protective film comprising a dry thin film according to the present invention will be described.
In one embodiment, the protective layer is an amorphous carbon film having a thickness of less than 200 nm. When the film thickness of the protective layer is thick, there is a fear of deformation such as stress peeling or warping of the protective film or the electrode itself. Furthermore, the amorphous carbon film is an insulating film inherently and has a large electric resistance. Therefore, the maximum film thickness is preferably less than 200 nm, more preferably less than 150 nm, and most preferably less than 50 nm, and is appropriately selected according to the use conditions.
In addition, the amorphous carbon film may contain other elements such as Si (silicon), F (fluorine), B (boron), S (sulfur) and various metals such as Ti and Al. .
Or as a dry film having a film thickness of silicon or metal having a film thickness of less than 200 nm, nitride, carbide, oxynitride, carbide, carbonitride, carbonitride, or carbonate nitride layer having a thickness of less than 200 nm. Become a protective layer.
The dry thin film may also be one to which a water and oil repellent element such as fluorine is added by a plasma process or the like.
Also in this case, when the film thickness of the protective layer is thick, there is a fear of deformation such as stress peeling or warping of the protective film or the electrode itself, and further, the maximum film thickness is 200 nm because the electrical resistance increases. The thickness is preferably less than 150 nm, more preferably less than 150 nm, and most preferably less than 50 nm, and is appropriately selected according to the use conditions.
However, in any of the embodiments of the present invention, when the thickness of the protective film made of the dry thin film according to the present invention is thin, the uneven portion in the electrode or the jig according to the present invention with a complicated uneven structure. And coverage of the protective film formed by the plasma dry process sufficiently on the surface constituting the wall surface (cross section) of the through hole can not be secured, and it is difficult to obtain corrosion resistance depending on the circumference It is desirable that the film thickness be more than 10 nm.

  Furthermore, the hardness of the protective layer is not particularly limited, but in order to suppress peeling and deformation of the protective film due to internal stress, the hardness of the protective layer is preferably less than Hv 4000 in Vickers hardness, more preferably less than Hv 3000, and more preferably Preferably, those less than Hv 2000 are preferable. However, since a protective layer with low hardness tends to lack gas barrier properties, it is desirable that the protective layer be at least Hv 500 or more, preferably Hv 1000 or more.

The dielectric constant (1 MHz) and the volume resistivity of the protective film made of the dry thin film according to the present invention are mainly as follows.
The dielectric constant of the amorphous carbon film is about 8 to 12, and the volume resistivity is about 10 4 to ¹⁴ Ω · cm.
Since the dielectric constant affects the formation of the electric double layer of the electrode, the dielectric constant of the aqueous solution is approximately 50 to 80, and the dielectric constant of water is 80, so the dielectric constant of the protective film consisting of a dry thin film is less than 50 Is more preferably 12 or less.
SiO ₂ : dielectric constant: 3.7 to 3.9 volume electrical resistivity × 10 ¹⁸ Ω · cm
Al ₂ O ₃ : dielectric constant: 9.5 to 10 volume resistivity 10 ¹⁴ Ω · cm
TiO ₂ (rutile): dielectric constant: 113 volume electrical resistivity × 10 ¹⁰ Ω · cm
Si ₃ N ₄ : dielectric constant: 7.3 to 10 volume resistivity 10 ¹⁴ Ω · cm
AlN: dielectric constant: 8.5 to 9 volume resistivity 10 ¹⁴ Ω · cm
TiC: volume electrical resistivity × 10 ¹² Ω · cm
TiN: volume electrical resistivity × 10 ¹² Ω · cm
SiC: volume resistivity × 10 ¹³ Ω · cm

  The protective film made of the dry thin film according to the present invention may be a plurality of laminated films of the above-mentioned various thin films, and even a mixed film can be used as long as it does not deviate from the scope of the present invention.

In one embodiment of the present invention, the protective layer such as the above-mentioned amorphous carbon film is formed by various dry processes such as plasma CVD, plasma PVD, atmospheric pressure plasma, sputtering, vacuum evaporation and the like. Is not particularly limited.
The surface roughness of the amorphous carbon film can be appropriately adjusted to a sharp and sharp shape by dry etching with oxygen after forming the amorphous carbon film, and the antibacterial property is thus obtained. It may also be possible to suppress the growth of bacteria and the like in the liquid sample during detection by applying (see Patent Document 3 above).

When a protective film made of a dry thin film according to the present invention is formed by a vacuum plasma process using a rectangular flat work by forming an electric field on a rectangular flat work, it is approximately 10 to 20 mm from the side (edge) of the peripheral portion of the rectangular flat work. It is verified as follows that pinholes due to plasma arcing and the like are concentrated and formed on the “frame-like surface” up to the inside of the extent width.
For example, after preparing and washing an aluminum alloy substrate (A 5052) (100 mm × 100 mm, 1 mm thick) having a rectangular shape in plan view, a voltage is applied to the aluminum alloy substrate to form an electric field around the substrate The substrate was set to a high pressure DCμ pulse plasma CVD apparatus capable of forming a dry thin film on the substrate, and the CVD apparatus was evacuated to 1 × 10 ⁻³ Pa. Thereafter, Ar (argon) gas with a flow rate of 30 SCCM and a gas pressure of 1.5 Pa was introduced into the CVD apparatus, and the substrate surface was plasma cleaned for 10 minutes by an applied voltage of -3 kVp. Subsequently, after Ar gas is exhausted from the CVD apparatus, acetylene gas with a flow rate of 30 SCCM and a gas pressure of 1.5 Pa is introduced into the CVD apparatus, a voltage of -4.5 kVp is applied, and a thickness of approximately 1 μm is applied to the substrate surface. Amorphous carbon film was formed. An aluminum alloy substrate having an amorphous carbon film formed on this surface was produced.
Subsequently, the aluminum alloy base on which the amorphous carbon film was formed was subjected to a corrosion deterioration accelerated test by salt spray. After performing salt water spraying for 24 hours according to JIS Z 2371 using a salt spray tester S-800 manufactured by Toyo Seiki Seisakusho Co., Ltd., each base material sample is taken out from the testing machine, washed with pure water and dried. The As a result of photographing the substrate after the drying with a CCD camera, the substrate is about 10 to 20 mm wide from the side (edge) of the peripheral portion of the aluminum alloy substrate on which the amorphous carbon film after the salt spray test is formed. The corrosion portion is concentrated on the inner surface, and the corrosion is caused by pinfall generated in the inner surface of about 10 to 20 mm from the side (edge) of the peripheral portion of the substrate due to plasma arcing. It can be estimated.

  From the above, when forming the protective film made of the dry thin film according to the present invention on the electrode substrate, the electrode substrate is temporarily formed on another conductive substrate whose entire periphery is 20 to 50 mm or more larger than the substrate When the electrode substrate is disposed on a temporary substrate, etc., an electric field is formed on the temporary substrate, and a protective film is formed by a vacuum plasma process using the electric field, approximately 10 from the edge of the peripheral portion of the temporary substrate. Pinfall due to plasma arcing is concentrated on an inner surface of about -20 mm, and for electrodes arranged further inside than the above range, there is less pinfall, or less pinfall on the surface of the electrode, or an electrode It may be possible to form an electrode having a protective film made of an insulating dry thin film according to the present invention with less uneven distribution of pinfall on the surface of the electrode.

(Water-repellent film, water- and oil-repellent film)
In one embodiment of the present invention, the fluorine-containing coupling agent film is a thin film comprising a fluorine-containing coupling agent. The fluorine-containing coupling agent film in one embodiment of the present invention is formed by applying a fluorine-containing coupling agent to the protective layer comprising the dry process, but the coating method is not particularly limited. It is preferable to carry out by a dry process such as a vacuum plasma method.
The water- and oil-repellent layer is a fluorine-containing insulating film, and the maximum film thickness is preferably less than 50 nm, more preferably less than 30 nm, and most preferably less than 20 nm, because electrical resistance increases. It is selected appropriately according to the conditions of use.
Note that the dielectric constant of the fluorine resin is 4.0 to 8.0, and the volume electrical resistivity is as large as ^{1018 to 22} Ω · cm.
The fluorine-containing coupling agent is a coupling agent having a fluorine substituent in its molecular structure, and exhibits a water- and oil-repellent function. The following fluorine-containing coupling agents can be used as the fluorine-containing coupling agent film.

_{(i) CF 3 (CF 2} ) 7 CH 2 CH 2 Si (OCH 3) 3
(ii) CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ SiCH ₃ Cl ₂
(iii) CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ SiCH ₃ (OCH ₃ ) ₂
(iv) (CH ₃ ) ₃ SiOSO ₂ CF ₃
(v) CF ₃ CON (CH ₃ ) SiCH _{3
(vi) CF 3 CH 2 CH} 2 Si (OCH 3) 3
(vii) CF ₃ CH ₂ SiCl _{3
(Viii) CF 3 (CF 2} ) 5 CH 2 CH 2 SiCl 3
_{(ix) CF 3 (CF 2} ) 5 CH 2 CH 2 Si (OCH 3) 3
_{(x) CF 3 (CF 2} ) 7 CH 2 CH 2 SiCl 3

  These fluorine coupling agents are just an example, and the fluorine-containing coupling agents applicable to the present invention are not limited to these examples. As a fluorine-containing coupling agent, for example, a solution of Fluorosurf FG-5010Z130-0.2 (Fluororesin 0.02 to 0.2%, fluorine-based solvent 99.8% to 99.98%) Can be used.

  In another embodiment of the present invention, fluorine is introduced into the thin film of the applied coupling agent after the fluorine-free coupling agent is applied to the substrate. The fluorine-containing coupling agent may be formed directly on the substrate, or may be formed on the upper layer of the fluorine-free coupling agent formed on the substrate.

  Coupling agents applicable to the present invention include silane coupling agents, titanate coupling agents, aluminate coupling agents, and zirconate coupling agents. These coupling agents can also be used in combination with other types of coupling agents.

  Silane coupling agents are widely spread without being exemplified. In the embodiments of the present invention, various commercially available silane coupling agents can be used. An example of a silane coupling agent applicable to the present invention is decyltrimethoxysilane (trade name "KBM-3103" Shin-Etsu Chemical Co., Ltd.) and the like.

  Examples of titanate coupling agents applicable to the present invention constituting the water and oil repellent layer include tetramethoxytitanate, tetraethoxytitanate, tetrapropoxytitanate, tetraisopropoxytitanate, tetrabutoxytitanate, isopropyltriisostearoyltitanate, isopropyltriol. Decylbenzene sulfonyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (di-tridecyl) phosphite titanate, bis ( Dioctyl pyrophosphate) Oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl trioctano Ruchitaneto, and include isopropyl tricumylphenyl titanate. The trade name "Plenact 38S" (Ajinomoto Fine Techno Co., Ltd.) is commercially available.

  Examples of the aluminate coupling agent applicable to the present invention constituting the water and oil repellent layer include aluminum alkylacetoacetate / diisopropylate, aluminum ethylacetoacetate / diisopropylate, aluminum trisethylacetoacetate, aluminum isopropylate, Aluminum diisopropylate monosecondary butyrate, aluminum secondary butyrate, aluminum ethylate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum trisacetylacetonate, and aluminum monoisopropoxy mono orexyethyl acetoacetate. A trade name "Plenact AL-M" (alkyl acetate aluminum diisopropylate, manufactured by Ajinomoto Fine Techno Co., Ltd.) is commercially available.

  Examples of the zirconia-based coupling agent applicable to the present invention constituting the water and oil repellent layer include neopentyl (diallyl) oxy, trimethacryl zirconate, tetra (2,2 diaryloxymethyl) butyl, di (ditridecyl) phosphate Zirconite and cyclo [dinopentyl (diallyl)] pyrophosphate dineopentyl (diallyl) zirconate are included. The trade name "Kenreact NZ01" (Kenrich) is commercially available.

  Next, the detection sensitivity of the electrode to be sacrificed in order to improve the corrosion resistance and the corrosion resistance, and a method of compensating for the others will be described.

(Surface modification)
Since the amorphous carbon film used in one embodiment of the present invention is intrinsically insulating, when the amorphous carbon film is formed on the surface of the electrode, the conductivity is lowered and the electrical sensitivity is lowered. It is known that when the amorphous carbon film is irradiated with an electromagnetic wave such as laser light or electron beam to such an extent that the amorphous carbon film does not evaporate, the remaining portion can be reformed into an electrical conductor in the irradiated portion (See Patent Document 2 above).
Therefore, in the amorphous carbon film formed on the electrode according to the embodiment of the present invention, the laser light is irradiated to the entire surface of the portion requiring conductivity or patterning irradiation is performed, and only the laser irradiation portion is made conductive. By doing this, the amorphous carbon film on one side can be reformed to the entire surface or a portion that is electrically conductive. In addition, it is possible to form an electrode made of a carbon material patterned by the original insulating portion of the amorphous carbon film and the conductive portion formed by laser irradiation.
The portion irradiated with the laser beam exhibits a hydrophilic functional group due to the formation of a polar functional group from the oxygen assist gas of laser beam irradiation or oxidation by heat. In addition, since the surface roughness is roughened, the wettability is improved, and a liquid sample can be collected in the relevant part and the wet spread can be made. It is effective for improving the electrical conductivity and sensitivity to an electrode having a protective film comprising the above, and the stability against corrosion.
Further, the conductor (carbon with conductivity) formed by modifying the amorphous carbon film by irradiating an electromagnetic wave such as a laser beam (electroconductive carbon) is less likely to cause ion migration, galvanic corrosion, etc. It can.

In the amorphous carbon film formed on the electrode according to the embodiment of the present invention, the structure that is made conductive by irradiating a laser beam or the like is a laser also on a non-planar surface such as a 3D three-dimensional component (electrode) or the like. Since any laser scanning portion can be reformed into a conductor by irradiation with light or the like, a 3D-shaped electrode necessary for inspection analysis can be easily created.
Further, as the laser light, known metal processing YAG lasers and the like can be used, and although not particularly limited, for example, UV light around a wavelength of 340 nm, UV-YAG pulse laser using irradiation with a pulse frequency of 10 kHz, etc. can also be used. .

(Use of surface wettability control of electrodes and inspection jigs, especially utilization of patterning part wettability control)
In addition, a dry thin film including any one or more of silicon or metal oxide, nitride, carbide, oxynitride, carbide, carbonitride, carbonitride or carbonate layer according to the second embodiment of the present invention By irradiating the plasma of oxygen or nitrogen, a large amount of polar functional groups are formed on the surface layer, and the strongly stable hydrophilic (hydrophilic / lipophilic) surface layer is also easily formed with the same plasma device (in process). It is possible to

The above-mentioned effect of improving the hydrophilicity and wettability of the surface is the oxide, nitride, carbide, oxynitride, carbonate, carbonitride or silicon or metal of the third embodiment of the present invention. It is also possible to obtain a water-repellent or water- and oil-repellent coating on a dry thin film containing any one or more of carbonic nitrides.
Furthermore, the wettability of the surface of the jig to be provided to the detection device is controlled by appropriately forming a film of water repellency, water / oil repellency, hydrophilicity, hydrophilic / lipophilic etc. on the surface of the jig to be provided not only for the electrode but also for the detection device. (Control of surface free energy) can be performed.

(Jig for patterning electrodes and detection equipment)
In one embodiment in this case, in the case where the conductive portion constituting the electrode is patterned on the insulating portion (for example, on the insulating electrode substrate) (such as a comb-like electrode), the insulating substrate portion is excluded. Only the surface layer portion of the electrode portion can be made more water repellent and water and oil repellent as compared to the insulating portion, or the insulating portion can be made more hydrophilic and hydrophilic and lipophilic than the electrode portion.
As described above, by changing the surface wettability of the electrode portion and the insulating portion entirely or in necessary portions, the arrangement of the liquid sample is appropriately guided to the portion having high wettability, and the liquid sample occupies the surface layer of the electrode ( The liquid sample of the sample is collected and disposed between the electrode and the electrode (insulation substrate) while preventing the acceleration of corrosion due to contact), and the necessary part of the electrode or jig is properly applied with a small amount of liquid sample It is easy to guide the sample to the (electrically conductive part etc.) and to arrange the liquid sample in the desired shape with wettability modification as required, and it is common to all other electrodes such as noble metal electrode etc. However, it is particularly suitable for complementing the sensitivity, improving the sensitivity, and imparting corrosion resistance of the electrode which is less sensitive to electricity with the passivity of the valve metal and the like according to the present invention.

Also, in this case, the electrode and the insulating dry thin film are alternately arranged in layers as in the “layer” by forming the electrode as a laminated structure including the metal layer (valve metal layer) according to the present invention and the dry thin film. By laminating and forming the sample contact and the electrode contact surface with the exposed cross section in the thickness direction of the layered product like the above-mentioned stratum, the insulating dry thin film (thickness) part is sandwiched in the exposed cross-sectional part. Also, it is possible to easily and inexpensively form an electrode exposed with (one thickness of) an electrode exposed in a layer shape as one electrode width, and one or a plurality of the electrodes, and a plurality of very thin wires exposed.
By adopting this laminated electrode structure, it is also possible to secure the absolute contact area of the electrode with the sample without expanding the area of the electrode in plan view, and therefore, it is also effective in all other electrodes such as noble metal electrodes. However, it is suitable for complementing the sensitivity of the electrode with poor sensitivity to electricity and improving the sensitivity particularly with the passivity of the valve metal and the like according to the present invention. In one embodiment of the present invention, the wettability of the cross-sectional portion of the laminated structure formed as described above is designed well with respect to the other portion, or the wettability of the other portion is designed to be poor. It becomes easy to introduce | transduce a liquid sample to the lamination | stacking electrode part which becomes, and to be filled efficiently.

  Recently, the width and interval of the wiring of the comb-shaped electrode appear narrower than 10 μm width, and when the electrode part has a “convex upward” structure, the structure water repellency derived from the concavo-convex structure formed by the electrode as a whole In some cases, the structure may exhibit oil repellency, and the liquid sample may not be sufficiently spread on the electrode portion (insulation portion). In this case, by making the electrode or the dry membrane part or both of them hydrophilic or hydrophilic / lipophilic, it is possible to wet and spread the liquid sample to a position necessary for measurement.

(Jig used for one-sided electrodes and detection equipment)
More water and oil repellent to silicon and metal oxides, nitrides, carbides, oxynitrides, carbonates, carbonitrides and carbonitrides formed by the dry process according to one embodiment of the present invention In the case where a film (hereinafter also referred to as a water repellent film or a water repellent layer) of the following is applied to an electrode consisting of a single surface, for example, the center on the electrode surface surrounded by the water repellent portion or the water and oil repellent portion It is possible to form and impart a more wettable portion including a hydrophilic surface or a hydrophilic / lipophilic surface or the like to the water-repellent portion or the water- and oil-repellent portion.
In this case, it is possible to collect the liquid sample in a highly wettable part on the same electrode in a desired shape and arrangement, and to allow the liquid sample to spread without wetting on the surface of the electrode so that it does not form water droplets. Although all the electrodes are effective, they are particularly suitable for complementing the sensitivity and improving the sensitivity of the electrode having poor electrical sensitivity due to the passivity of the valve metal and the like according to the present invention.

Usually, when performing detection, measurement, analysis, analysis, etc. on a fluid sample such as a liquid sample, the liquid sample is often held in a concave or mortar-shaped base material. In this case, for example, when the liquid sample is wetted by capillary pressure or the like on the wall surface of the portion constituting the recess, the sample is unevenly distributed or insufficient at the bottom of the recess, or the liquid sample held and stored in the recess is the wall surface portion In some cases, the liquid surface may form a “convex downward” (concave) aspect in the concave portion holding and housing portion when it gets wet on the wall surface.
In order to avoid such a situation, for example, the wall portion of the concave portion holding the liquid sample is made to be a water-repellent, water- and oil-repellent wall surface, or the liquid sample wettability of the bottom is made higher than that of the concave wall. There is a corresponding method such as (for example, a hydrophilic or hydrophilic / lipophilic surface).

Furthermore, a portion where the liquid sample is well wetted is formed in a desired shape on a flat substrate without a partition, and furthermore, the portion around the portion is made difficult to wet (a repelling portion) of the liquid sample, that is, By partially forming a portion having different wettability to the liquid sample on the electrode or jig surface in contact with the liquid sample, the partition for the purpose of prevention or retention of the liquid sample is eliminated, and the liquid sample becomes wet to the concave wall surface And other problems can be solved.
Although it is ideal to form the water-repellent or water- and oil-repellent portion and the hydrophilic or hydrophilic-lipophilic portion in the formation of the partially different portions of the wettability, it is ideal to form the portions having different wettability. In the case of oil, the difference in the contact angle is approximately 20 ° or more in the case of oil, and approximately 40 ° or more in the case of water, the “pinning effect of wetting” which appears when the liquid advances to different wettability surfaces The “hysteresis effect” can be used to control the flow and outflow of the liquid sample.

As described above, in the preparation of the portions having different wettability on the same surface, the water-repellent or water- and oil-repellent portion, the hydrophilic or hydrophilic / lipophilic portion, and the untreated substrate itself (the substrate itself It is possible to control the flowability (washability and holdability) of the liquid in contact with the surface layer by finely dividing it from the wetness part).
By adopting the structure on the surface of the detection electrode and the jig for detection, the liquid sample which is the sample is immediately and completely discarded after measurement, and the residue on the electrode is suppressed, and the same electrode of the next sample or Re-measurement with a jig is possible and may be easy.

(Utilization of zeta potential of protective film surface)
Among various samples, those mainly composed of biomolecules such as proteins, such as bacteria and hair, are negatively charged because the carboxyl groups and phosphate groups on the surface are dissociated under neutral conditions around pH 7. Since it is common to have an isoelectric point in a weakly acidic region, a base material that has an isoelectric point in an alkaline region and is positively charged under neutral conditions, such as metals such as stainless steel It is easy to be adsorbed by the electrode for detection, the jig for detection, etc. In addition, microbial cells are also in a state of being easily adsorbed (adhered) to the surface of a metal electrode or jig that is normally positively charged under neutral conditions near pH 7.
As described above, when the electrode or jig as the substrate is present under neutral conditions, the substrate (for example, the electrode for detection, the jig for detection, etc.) is almost positively charged if it is metal. Since substances containing biomolecules, such as proteins, as their main components are negatively charged, the substances are electrically adsorbed to a substrate such as an electrode or jig.
In the embodiment of the present invention, adjusting the isoelectric point of a protective film such as an amorphous carbon film formed on the surface of an electrode for detection, a jig for detection or the like, or a liquid sample containing a biomolecule By adjusting the pH, the difference between the polarity of electrodes for detection, jigs for detection, etc. and the sample mainly composed of biomolecules such as protein is used to detect the sample composed of biomolecules or the electrode for detection It becomes possible to make it adsorb to the surface layer of a jig or the like, or to repel it in reverse.

  Here, the protein includes proteins, polypeptides and oligopeptides having any size, structure and function, and examples thereof include various proteins, enzymes, antigens, antibodies, lectins, cell membrane receptors and the like.

In one embodiment of the present invention, the amorphous carbon film is irradiated with oxygen plasma or nitrogen plasma to form a surface layer of the amorphous carbon film with a functional group such as a carboxyl group (-COOH) or a hydroxyl group (-OH). It is possible to form a group. Once deprived, -COO ionized negatively on the surface layer of the amorphous carbon film - H ⁺ ions of these functional groups hydroxide ion present in an alkali solution ^{(OH) -} group or -O ^- groups As it is generated, the surface layer of the amorphous carbon film can be negatively charged.
Thus, by forming the carboxyl group (-COOH) and the hydroxyl group (-OH) on the surface layer of the amorphous carbon film, the amorphous carbon film is further negatively charged, and negatively charged protein etc. It is possible to suppress the adhesion of a sample whose main component is a biomolecule.

In one embodiment, the structure in which the amorphous carbon film containing Si is further irradiated with oxygen plasma, and SiO ₂ (quartz, whose isoelectric point is about pH 2.5) is obtained from hydrogen and carbon not containing Si. The isoelectric point of the amorphous carbon film and the isoelectric point further on the acidic region side than the isoelectric point of the resin such as PET (the lowest iseta potential is about -70 mV at about pH 4 and about pH 8 to 9). Since it has a point (for example, having an isoelectric point of less than pH 4), it becomes possible to prevent the adhesion of the adhesion preventing target substance in a wider area on the more acidic side.

The isoelectric point of what formed the amorphous carbon film | membrane comprised from hydrogen and carbon can be confirmed at pH 3.8 vicinity. Therefore, if the sample is negatively charged, if the pH is made less than 3.8, the amorphous carbon film composed of hydrogen and carbon with a negative zeta potential formed on the electrode (minusly charged (Rather than negatively charged specimens) on an amorphous carbon film composed of hydrogen and carbon with positive zeta potential if the pH is in the range above 3.8. It becomes easy to adsorb.
In this way, it may be possible to attach the sample to the electrode, to repel it, and to separate it.

On the other hand, it can be confirmed that the isoelectric point of one obtained by adding Si and O to an amorphous carbon film composed of hydrogen and carbon is more acidic than pH 2.5.
The zeta potential of an amorphous carbon film composed of hydrogen and carbon is approximately pH 4: -5 mV, pH 5: -50 mV, pH 6: -80 mV, pH 7:-95 mV, pH 8--105 mV.
In addition, the zeta potential of an amorphous carbon film composed of hydrogen and carbon and Si and O added thereto is generally pH 4: 50 mV, pH 5: 85 mV, pH 6: 98 mV, pH 7: 100 mV, pH 8: 105 mV It is. Thus, it has been confirmed that the isoelectric point shifts to the acid side by modifying the amorphous carbon film to, for example, an amorphous carbon film containing Si and oxygen. Furthermore, larger negative zeta potential can be obtained in the same pH environment.

  As described above, by properly understanding and adjusting the zeta potential of the protective film formed on the surface layer of the electrode, in the sensor for detection, evaluation, analysis, and analysis device, members constituting the detection system, for example, the detection electrode and detection To handle or hold the sample etc. Unpredictable changes (such as unexpected adsorption or repulsion noise to the detection electrode of the biological molecule which is the sample, etc.) of the jig etc. are grasped or eliminated as much as possible. It can improve the limits.

  EXAMPLES Examples according to various embodiments of the present invention will be described below, but the following examples are exemplifications, and the present invention is not limited to the examples described below.

Verification of conductivity in corrosive atmosphere
A required number of aluminum foil (size: 100 mm × 100 mm) base materials (hereinafter sometimes referred to simply as “aluminum foil base materials”) are prepared, and four types of samples are prepared according to Comparative Example 1 and Examples 1 to 3 below. Created.

(Comparative example 1)
First, an untreated aluminum foil substrate was used as a sample of Comparative Example 1.

Example 1
On the surface of the prepared aluminum foil base, an amorphous carbon film containing Si was formed with a thickness of 20 nm by the known method as follows.
First, the prepared aluminum foil base was put into a high pressure pulse plasma CVD apparatus, and the reaction container of the CVD apparatus was vacuum-decompressed to 1 × 10 ⁻³ Pa. Usually, argon gas is introduced first and the substrate is cleaned by argon gas plasma, but the cleaning step is omitted to preserve the passivation layer. Next, a trimethylsilane gas is introduced at a flow rate of 30 SCCM and a gas pressure of 2 Pa into the CVD apparatus, a plasma is formed under the conditions of an applied voltage of -4 kV, a pulse frequency of 10 kHz, and a pulse width of 10 μs, and Si is contained on an aluminum foil substrate. An amorphous carbon film was formed with a thickness of approximately 20 nm. The obtained product was used as a sample of Example 1.

(Example 2)
A fluorine-containing silane coupling agent (Fluoro Technology Co., Ltd.) was formed on the surface (the surface on which the amorphous carbon film was formed) of the aluminum foil substrate on which the amorphous carbon film containing Si formed by the method of Example 1 was formed. Fluorosurf FG-5010 Z130-0.2) was applied using Bencot (product name) manufactured by Asahi Kasei Corporation. Two days later, after being cleaned for 1 minute in an ultrasonic cleaning tank filled with IPA (isopropyl alcohol), the obtained sample was used as a sample of Example 2.

(Example 3)
An amorphous carbon film was formed to a thickness of 20 nm on the surface of the prepared aluminum foil base as follows.
First, the prepared aluminum foil base was put into a high pressure pulse plasma CVD apparatus, and the reaction container of the CVD apparatus was vacuum-decompressed to 1 × 10 ⁻³ Pa. Usually, argon gas is introduced first and the substrate is cleaned by argon gas plasma, but the cleaning step is omitted to preserve the passivation layer. Next, an acetylene gas is introduced at a flow rate of 30 SCCM and a gas pressure of 2 Pa into the CVD apparatus, a plasma is formed under the conditions of an applied voltage of -4 kV, a pulse frequency of 10 kHz and a pulse width of 10 μs, and amorphous carbon is deposited on an aluminum foil substrate. The film was formed with a thickness of approximately 20 nm. The obtained product was used as a sample of Example 3.

(Corrosion of each sample)
Each sample was corroded under the conditions of Cass test according to JIS Z2371.
The Cass test is an environmental test to determine the degree of corrosion (rust) of a sample, and the liquid used for the test is made acidic (pH 3.1 to 3.3) with acetic acid and further chlorided with copper chloride added. It is effective as a corrosion promotion test and can be evaluated in a short test time as compared with the test using a sodium chloride aqueous solution and using a neutral salt solution which is the same test.
In particular,
○ Cass tester CAP-90 Suga Test Instruments Co., Ltd. ○ According to JIS Z2371 (Cas test) • Test solution: Sodium chloride 50 ± 5 g / L, copper (II) chloride 0.205 ± 0.015 g / L, pH = 3. 1 to 3.3 (acetic acid)
· Spraying room temperature: 50 ± 2 ° C
Spray amount: 1.5 ± 0.5 mL / h (80 cm ² )
○ Spraying: Spray tower method (There is a spray tower at the center of the spray chamber)
○ Size of the test tank: Depth 60 cm × width 86 cm × height 22 cm
○ Test time: 6 hours

(Measurement of electrical resistance)
After the corrosion of each sample was maintained and accelerated under the condition of 6 hours cast test, the electrical resistance was measured at a load voltage of about 0.39 v by a known four-terminal measurement method. The resistance measurement device used Agilent 34420A.
The results are shown in Table 1.

The electrical resistance of the aluminum foil which is a base material of each sample is 0.0000982 Ω. Further, the electric resistance of each example before the cast test was 0.01344 Ω in Example 1, 0.03554 Ω in Example 2, and 0.012262 Ω in Example 3.
First of all, the electric resistance (Ω) of the sample of each example in which the protective film is formed on the aluminum foil substrate is × 10 ^-2 (-2 excess production), which is a level usable as an electrode You can confirm that.
After the cast test, the increase in resistance before and after the cast test is suppressed to a low level compared to the comparative example in any of the examples, and the aluminum foil is protected from corrosion and the electrical resistance is increased by the corrosion film of aluminum. Is extremely low. Moreover, the significant difference of the increase rate of resistance in each Example can also be confirmed, and it can be understood as the difference of the corrosion prevention effect in this cast test.

As a result of the verification, the electrical resistance of the sample of the comparative example (untreated aluminum foil) increased by three orders of magnitude, and was conversely larger than the electrical resistance value of the sample of each example in which the protective film was formed.
In addition, the samples of each example do not cause film exfoliation, and further maintain low electrical conductivity of × 10 ^-2 (-2 excess production) that can be used as an electrode, and in particular, in the surface layer of the protective film Further, in Example 2 in which the thin film fluororesin layer was formed, it was confirmed that the rate of increase in the electrical resistance was the lowest, and the stability (corrosion resistant protection performance) was exhibited.

About the film of the sample of Example 1 and the sample of Example 3 before the said corrosion test, the measurement of the surface electrical resistivity was performed by the measurement of the sheet resistance by the double ring method (constant voltage amperometry).
The measuring device is Agilent Technologies High Resistance Meter 4339B, Agilent Technologies Resistance Cell 16008B
Main electrode size 26 mmφ, counter electrode inner diameter 38 mmφ, card electrode 110 mm × 110 mm
It is a condition of a load of 1 kgf.
In addition, the measurement environment is measuring temperature: 23 ± 1 ° C., humidity: 50% ± 5%, in the electromagnetic measurement room (shield room).

The measurement results of surface resistivity at a test voltage of 10 V are 2.9 × 10 ⁹ Ω / □ for the sample of Example 3 and 1.6 × 10 ¹² Ω / □ for the sample of Example 1; It was confirmed that the amorphous carbon film containing Si in Example 1 has an extremely larger surface resistivity than the amorphous carbon film not containing Si.

<< Confirmation of the state of stress separation in the comb electrode>
The comb-shaped electrodes made of valve metal and arranged at intervals have a long side extension per area compared to the surface area, and are electrodes in which adhesion of the substrate is difficult because of fine floating island state.
The situation of stress separation in the case of forming a thin film formed by a dry process on such an electrode was confirmed as follows.
A soda lime glass substrate of 100 mm × 100 mm rectangle and 1 mm thick was prepared.
After ultrasonic cleaning, a fine comb-shaped electrode having a width of 30 μm and a space of 30 μm, such as an adjacent counter electrode, was drawn and formed with a resist by a known photolithography method to form a “mold”.

Then, sputtering formation of the aluminum thin film was carried out using SRDS-7000T type | mold general-purpose small film-forming apparatus (made by Sanyu Electronics). This sputtering uses Ar gas with a flow rate of 100 sccm and a pressure of 3 Pa as a sputtering gas, an initial vacuum of 10 ^-3 Pa, a DC of 400 W, a TS distance of 100 mm, an OFS of 55 mm, and a sample table rotation speed of 10 rpm 5 I went for a minute. An aluminum thin film having a thickness of about 100 nm was formed on a glass substrate, and then the resist was removed by etching to form a comb electrode made of aluminum.
As the Al target, Al 4 N 4 “φ × 5t purity 99.99%” was used.

Next, in the same manner as in Example 1, a dry protective film was formed as follows.
First, an amorphous carbon film containing Si was formed to a thickness of 200 nm in advance by a known plasma CVD method on the entire glass substrate on which an Al (aluminum) electrode was formed by a sputtering method.
The formation of the amorphous carbon film containing Si was performed as follows. First, the prepared glass substrate was put into a high pressure pulse plasma CVD apparatus, and the reaction vessel of the CVD apparatus was vacuum reduced to 1 × 10 ⁻³ Pa. Usually, argon gas is introduced first, and the substrate is usually cleaned here by argon gas plasma, but the cleaning step is omitted to preserve the passivation layer. Next, a trimethylsilane gas is introduced at a flow rate of 30 SCCM and a gas pressure of 2 Pa into the CVD apparatus, and plasma is applied under the conditions of an applied voltage of -5 kV, a pulse frequency of 10 kHz, and a pulse width of 10 μs, and non-Si containing Al (aluminum) electrode. A crystalline carbon film was formed with a thickness of approximately 200 nm.

One week after the above treatment, the condition of the Al electrode in which the amorphous carbon film containing Si was formed to a thickness of about 200 nm was observed, but it contains Al electrode and base, Al electrode and Si. It was confirmed that no stress separation or the like occurred between the amorphous carbon films.
Further, on the surface of the Al electrode on which the amorphous carbon film containing Si is formed (the surface on which the amorphous carbon film is formed), a fluorine-containing silane coupling agent (Fluorosurf FG-5010Z130- from Fluoro Technology) is formed. 0.2) was spray applied, and one week after treatment, the condition of the Al electrode was observed, but stress peeling etc. between the Al electrode and the base, between the Al electrode and the amorphous carbon film containing Si, etc. Was confirmed to have not occurred.
It was confirmed that the fluorine-containing silane coupling agent had a low surface tension, and the adhesion between the peeling gap and the film was apt to promote the floating of the film, but no problem occurred.

«Confirmation of barrier property»
Next, an amorphous carbon film is formed with a thickness of about 35 nm on a PET film (Lumirror T60 (t = 25 μm) of Toray Industries, Inc.) in the same manner as in Example 3, and hydrogen, water vapor, and oxygen barrier properties are obtained. confirmed.
In addition, the measurement was implemented by GTR Tech GTR-10XFKS, JIS-K7176-2 gas chromatograph method (25 degree CDRY).

As a result, the gas permeability of untreated PET film Lumirror T60 (t = 25 μm) itself is
・ Hydrogen permeability: 2599 ml / (m ² · 24 h / atm)
- water vapor transmission ^{rate: 64.0g / (m 2 · 2day} )
Oxygen permeability: 79.0 cc / (m ² · day / atm)
However, after forming the amorphous carbon film,
· Hydrogen permeability: 73.5 ml / (m ² · 24 h / atm) approximately 93% of gas permeation prevention · water vapor permeability: 2.0 g / (m ² · 2 days)
-Oxygen permeability: 9.0 cc / (m ² · day / atm)
And very high gas barrier properties were confirmed.

For example, a film of Al _x O _y or Si _x O _y also has high water vapor and oxygen barrier properties equal to or higher than that of Example 3 derived from its film density and the like. It can be estimated that there is

<< Patternability of liquid by surface wettability control >>
It confirmed about the patterning property of the liquid by wettability control of the surface.
First, a rectangular sheet of PET film Lumirror T60 (t = 100 μm) width 600 mm length 600 mm was subjected to surface treatment of hydrophilicity on the entire surface.
The PET film was set in a CVD apparatus, and the CVD apparatus was evacuated to 1 × 10 ⁻³ Pa. Thereafter, argon gas with a flow rate of 30 SCCM and a gas pressure of 2 Pa was introduced into the CVD apparatus, and the substrate surface was plasma cleaned for 2 minutes by an applied voltage of -3 kVp. Subsequently, after argon gas is exhausted from the CVD apparatus, trimethylsilane gas having a flow rate of 30 SCCM and a gas pressure of 1 Pa is introduced into the CVD apparatus, a voltage of -3 kVp is applied, and Si of 30 nm thickness is contained on the substrate surface. An amorphous carbon film was formed.
After exhausting trimethylsilane gas from the CVD apparatus, oxygen gas with a flow rate of 30 SCCM and a gas pressure of 1 Pa is introduced into the CVD apparatus, a voltage of -3 kVp is applied, and the substrate surface is irradiated with oxygen plasma for 1 minute. An oily surface was formed.

Subsequently, a screen printing ink (Reagent Chemical ink TMS-397) usable for masking (patterning) in plasma process and easily removable with water after formation is used as a patterning resist and has a diameter of approximately φ500 μm. The ink was transferred onto the hydrophilic / lipophilic surface in a pattern in which the ink remained in the hexagonal portion and the ink was not printed with a width of 100 μm and six sides of the hexagonal portion.
Subsequently, the entire surface of the PET film is spray-coated with a fluorine-containing silane coupling agent (Fluorosurf FG-5010Z130-0.2, manufactured by Fluoro Technology) and dried and fixed for 1 day to form a pattern of "ink not printed" 100 μm wide A water and oil repellent layer made of a fluorine-containing silane coupling agent was formed on the wire part surrounding the square.
Subsequently, the PET film is charged into an ultrasonic cleaning machine, the ink portion is peeled off, and the lower layer hydrophilic / lipophilic Si and oxygen-containing amorphous carbon film which has been masked by the ink is exposed to a diameter of about 500 μmφ. A 100 μm wide water- and oil-repellent surface formed a surface surrounding a hexagonal hydrophilic and lipophilic portion.
Pure water was sprayed on the surface consisting of the hydrophilic and lipophilic surface portion and the water and oil repellent surface portion.

FIG. 1 is a photograph of both surfaces sprayed with pure water. The part that appears white in the center is the reflected part of the light of the CCD camera.
It can be confirmed from the photograph that pure water is spread only in the hydrophilic and lipophilic hexagonal part.
As described above, it has been confirmed that it is possible to dispose the liquid sample in a desired form in a desired form as needed by forming (the difference of) the surface wettability.

Comparison of resin adhesion of amorphous carbon film containing Si and amorphous carbon film not containing Si
Two squares of 100 mm in size and 100 mm in size were prepared from polyester mesh made of NBC mesh.
(Formation of a sample in which an amorphous carbon film layer containing no Si is formed after forming an amorphous carbon film adhesion layer containing Si less than 60% of hydrogen free to an organic polymer base material)
The polyester mesh sample is placed flat on a stainless steel plate, and the polyester mesh sample is placed in a reaction vessel of a film forming chamber of a known plasma CVD apparatus of a direct current pulse system so that a negative voltage can be applied to the stainless steel plate. An amorphous carbon film was formed on the side opposite to the side in contact with the stainless steel. Specifically, the deposition chamber reaction container was evacuated to a vacuum of 1 × 10 ⁻³ Pa. Next, Ar gas was introduced at a gas flow rate of 30 SCCM, gas pressure 2 Pa, Ar gas plasma was generated under the condition of applied voltage -3 kVp, and the substrate on the sample table was cleaned for 1 minute. After Ar gas is exhausted and cooled for 15 minutes, trimethylsilane gas is introduced into the reaction vessel at a flow rate of 30 SCCM, 1.5 Pa gas pressure, applied voltage -3 kVp, pulse width 10 μs, pulse frequency 10 kHz and contains Si for 1 minute An amorphous carbon film was formed. The carbon content of the base material adhesion layer of the amorphous carbon film containing Si is about 53.2 at% on a hydrogen free basis, and the content of Si is about 37.6 at%.
After exhausting trimethylsilane gas and cooling for 15 minutes, acetylene gas is introduced into the reaction vessel at a flow rate of 30 SCCM, 1.5 Pa gas pressure, applied voltage-3.5 kVp, pulse width 10 μs, pulse frequency 10 kHz for 3 minutes A crystalline carbon film not containing Si, consisting only of hydrogen and carbon was formed, and once the film formation was interrupted and cooled for 15 minutes, amorphous carbon consisting only of hydrogen and carbon containing no Si under the same conditions again. A film was repeatedly formed at the same film forming time and cooling time to form an amorphous carbon film having a film thickness of approximately 100 nm. Thereafter, the vacuum vessel was returned to normal pressure, and a polyester mesh sample was taken out to be a comparative example.

(Formation of a sample in which an amorphous carbon film layer containing only hydrogen and carbon is formed on an organic polymer substrate and then an Si-free amorphous carbon film layer is formed)
Subsequently, the other polyester mesh sample is placed flat on a stainless steel plate, and is installed in a reaction vessel of a film forming chamber of a known plasma CVD apparatus of a direct current pulse system so that a negative voltage can be applied to the stainless steel plate. An amorphous carbon film was formed. The film forming chamber reaction vessel was evacuated to a vacuum of 1 × 10 ⁻³ Pa. Next, Ar gas was introduced at a gas flow rate of 30 SCCM, gas pressure 2 Pa, Ar gas plasma was generated under the condition of applied voltage -3 kVp, and the substrate on the sample table was cleaned for 1 minute. After Ar gas is exhausted and cooled for 15 minutes, acetylene gas is introduced into the reaction vessel at a flow rate of 30 SCCM, 1.5 Pa gas pressure, applied voltage-3.0 kVp, pulse width 10 μs, pulse frequency 10 kHz for 1 minute Si Amorphous carbon film (part corresponding to the adhesion layer not containing Si) containing only hydrogen and carbon, which does not contain hydrogen, is temporarily suspended, cooled for 15 minutes, then acetylene gas is added to the reaction vessel A crystalline carbon film consisting only of hydrogen and carbon, which contains no Si and is introduced at a flow rate of 30 SCCM and a gas pressure of 1.5 Pa, applied voltage-3.5 kVp, pulse width 10 μs, pulse frequency 10 kHz for 3 minutes Once the film formation was interrupted and cooled for 15 minutes, an amorphous carbon film consisting of only hydrogen and carbon containing no Si was repeatedly formed under the same conditions under the same film formation time and cooling time. An amorphous carbon film having a thickness of about 100 nm was formed. After that, the vacuum vessel was returned to normal pressure, and a polyester mesh sample was taken out and used as an example.

The friction and wear test was performed on the comparative example and the example.
The friction and wear test was carried out using Tribo Gear HHS-2000 manufactured by Shinto Scientific Co., Ltd. under the following measurement conditions at normal temperature and without lubrication on the surface on which the amorphous carbon film of each sample was formed. The coefficient of friction of each sample surface was measured while repeatedly reciprocating 0 mm SUJ 2 indenter. The measurement of the coefficient of friction was carried out by constant pressure reciprocating measurement.
Measurement conditions and distance: 20 mm
・ Measurement speed: 5mm / sec
・ Load of indenter: 100g constant

The results of the comparative example and the example are shown in FIG. 2 and FIG. 3, respectively.
In the graphs of FIGS. 2 and 3, the vertical axis represents the coefficient of friction (μ), and the horizontal axis represents the number of reciprocations of friction.
In the comparative example, the coefficient of friction (vertical axis) exceeds 0.3 (μ) in the vicinity of the 5th reciprocation, and largely exceeds less than 0.2 μ that the amorphous carbon film usually exhibits. It can be estimated that partial peeling has occurred.
On the other hand, it can be confirmed that the coefficient of friction (vertical axis) of the example is less than 0.2 μm and stable up to 50 cycles, and it can be estimated that the base material adhesiveness of the amorphous carbon film is excellent. .

From the above results, when forming an amorphous carbon film in close contact with a substrate made of an organic polymer such as resin or rubber, it is the same as C (carbon) and H (hydrogen) which are compositions of organic polymers such as resin. An amorphous carbon film containing Si, which is often used when forming an amorphous carbon film in close contact with a metal substrate, in the case of directly forming an amorphous carbon film consisting of hydrogen and carbon consisting of the composition It can be estimated that the adhesion is superior to that in which an amorphous carbon film consisting of hydrogen and carbon is formed after the intermediate layer is formed as the adhesion layer.
This means that, for example, when it is desired to efficiently form a gas barrier film of both water vapor and oxygen consisting of an amorphous carbon film, the amorphous carbon film consisting of hydrogen and carbon is excellent in the water vapor permeation preventing property and Si ( Furthermore, it is known that an amorphous carbon film containing Si and oxygen is excellent in oxygen gas permeation prevention performance. Therefore, in the case of preventing permeation of both water vapor and oxygen to the base material made of an organic polymer material such as resin, an amorphous carbon film made of hydrogen and carbon is first formed on the base material and then Si A method of forming an amorphous carbon film containing Si, forming an amorphous carbon film containing Si directly on a substrate made of an organic polymer material, and forming an amorphous carbon film consisting of hydrogen and carbon later It could be estimated that it was better. Of course, it is also possible to successively stack a plurality of layers or the like after that, an amorphous carbon film containing Si or an amorphous carbon film consisting of hydrogen and carbon.

Claims (10)

A substrate, an electrode made of at least a part of a valve metal formed on the substrate, and a protective layer having a thickness of more than 10 nm and less than 200 nm formed on the electrode;
An electrode structure for a sensor or an evaluation analyzer, wherein the protective layer comprises an amorphous carbon film. A substrate, an electrode made of at least a part of a valve metal formed on the substrate, and a protective layer having a thickness of more than 10 nm and less than 200 nm formed by a dry process on the electrode;
A sensor characterized in that the protective layer is a thin film containing any one or more of an oxide, a nitride, a carbide, an oxynitride, a carbonitride, a carbonitride or a carbonitride layer of silicon or metal. Electrode structure for use with or for an analytical analysis device.   The electrode structure for a device for a sensor or an evaluation analysis device according to claim 1 or 2, wherein a water-repellent and / or water- and oil-repellent thin film layer is provided on the protective layer.   The said thin film layer is a resin layer which consists of a fluorine-containing coupling agent with a film thickness of less than 50 nm, The electrode structure for the apparatus for sensors for sensors or evaluation analysis of Claim 3 characterized by the above-mentioned.   The said valve metal equips the surface layer with a passivity layer, The electrode structure for the apparatus for sensors for sensors or evaluation analysis of any one of the Claims 1-3 characterized by the above-mentioned.   The electrode structure for a sensor or a device for evaluation analysis according to any one of claims 1 to 5, wherein the electrical resistance under a load voltage of 0.39 v is less than 0.45 Ω.   The outermost surface of the substrate on which the electrode is not formed and / or the outermost surface of the portion on which the electrode is formed is provided with a surface having different surface wettability with water and / or oil. An electrode structure for the sensor or the device for evaluation analysis according to any one of.   8. The sensor or evaluation according to any one of claims 1 to 7, wherein the protective film conforms to the standard of food, additives, etc. (Ministry of Health and Welfare Notification No. 370 of 1959). Electrode structure for analytical devices.   The electrode structure for a sensor or evaluation analysis according to any one of claims 1 to 8, wherein the protective film has a hydrogen gas permeation preventing property larger than the base material.   The electrode structure for a sensor or evaluation analysis according to any one of claims 1 to 9, wherein a dielectric constant of the protective film is less than 50.