Electrochemical sensor, multi-imposed sheet, and method of manufacturing electrochemical sensor

Abstract

To provide an electrochemical sensor that may offer improved sensitivity.SOLUTION: An electrochemical sensor is provided, comprising an insulative substrate 2, and an electrode pattern provided on the insulative substrate 2. The electrode pattern includes a sensor portion 50 and non-sensor portion 51 that are made up of continuous layers. The sensor portion 50 is designed to be thinner than the non-sensor portion 51.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrochemical sensor, a multi-sided attached sheet, and a method for manufacturing an electrochemical sensor.

Background Art

[0002] In recent years, biosensors have been widely used in fields such as medicine. A biosensor can detect an analyte in a sample by an electrochemical reaction. In a biosensor, a structure in which detection electrodes are formed on an insulating sheet is common. As the electrode material, a carbon paste containing conductive carbon particles may be used from the viewpoint of suppressing the manufacturing cost.

[0003] Such a biosensor can analyze a biological sample such as blood, sweat, or saliva to detect a specific substance. The biosensor is also applied to POCT (Point Of Care Testing) that enables simple clinical diagnosis at home without going to a hospital.

[0004] The biosensor used in POCT is required to be able to detect a sample with a low concentration of biomolecules and to be measurable with a small amount of sample in order to reduce the physical burden on the patient. In such a case, high sensitivity of the sensor is required.

[0005] Also, from a hygienic point of view, it is desirable that the biosensor be disposable. For this reason, it is necessary to keep the price per sensor low, and low manufacturing cost and high production efficiency are also important factors.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention provides an electrochemical sensor capable of improving sensitivity, a multi-sided attachment sheet, and a method for manufacturing an electrochemical sensor.

Means for Solving the Problems

[0008] According to a first aspect of the present invention, there is provided an electrochemical sensor including an insulating substrate and an electrode pattern provided on the insulating substrate, the electrode pattern including a sensor portion and a non-sensor portion formed of a continuous layer, and a film thickness of the sensor portion being thinner than a film thickness of the non-sensor portion.

[0009] According to a second aspect of the present invention, when a maximum film thickness of the sensor portion is TA and a maximum film thickness of the non-sensor portion is TB, a film thickness ratio TA / TB satisfies the following relationship 0.4 ≦ TA / TB ≦ 0.7 The electrochemical sensor according to the first aspect is provided.

[0010] According to a third aspect of the present invention, there is provided the electrochemical sensor according to the first aspect, wherein the sensor portion includes a working electrode and a counter electrode provided adjacent to the working electrode, and the non-sensor portion includes a first wiring electrically connected to the working electrode and a second wiring electrically connected to the counter electrode.

[0011] According to a fourth aspect of the present invention, there is provided the electrochemical sensor according to the third aspect, further including a reference electrode provided adjacent to the working electrode, and the non-sensor portion including a third wiring electrically connected to the reference electrode.

[0012] According to a fifth aspect of the present invention, there is provided the electrochemical sensor according to the third aspect, further including an insulating layer that insulates the working electrode and the counter electrode and covers the first wiring and the second wiring.

[0013] According to a sixth aspect of the present invention, there is provided an electrochemical sensor according to the first aspect, wherein the sensor part and the non-sensor part are made of a conductive material containing carbon.

[0014] According to a seventh aspect of the present invention, there is provided a multi-sided sheet including a plurality of electrode chips provided on a sheet-like insulating substrate, each of the plurality of electrode chips being the electrochemical sensor of the first aspect.

[0015] According to an eighth aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor, including a step of forming an electrode pattern including a sensor part and a non-sensor part formed of a continuous layer on an insulating substrate, and a step of polishing the sensor part to make the film thickness of the sensor part thinner than the film thickness of the non-sensor part.

[0016] According to a ninth aspect of the present invention, when the maximum film thickness of the sensor part is TA and the maximum film thickness of the non-sensor part is TB, the film thickness ratio TA / TB satisfies the following relationship 0.4 ≦ TA / TB ≦ 0.7 There is provided a method for manufacturing an electrochemical sensor according to the eighth aspect.

[0017] According to a tenth aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor according to the eighth aspect, wherein the sensor part includes a working electrode and a counter electrode provided adjacent to the working electrode, and the non-sensor part includes a first wiring electrically connected to the working electrode and a second wiring electrically connected to the counter electrode.

[0018] According to an eleventh aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor according to the tenth aspect, further including a step of forming a reference electrode provided adjacent to the working electrode on an end portion of a third wiring included in the non-sensor part.

[0019] According to a twelfth aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor according to the tenth aspect, further including a step of forming an insulating layer that insulates the working electrode and the counter electrode and coats the first wiring and the second wiring.

[0020] According to the 13th aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor according to the 8th aspect, wherein the sensor part and the non-sensor part are made of a conductive material containing carbon.

Effects of the Invention

[0021] According to the present invention, it is possible to provide an electrochemical sensor capable of improving sensitivity, a multi-sided attachment sheet, and a method for manufacturing an electrochemical sensor.

Brief Description of the Drawings

[0022]

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Mode for Carrying Out the Invention

[0023] Hereinafter, embodiments will be described with reference to the drawings. However, the drawings are schematic or conceptual, and the dimensions and ratios of each drawing are not necessarily the same as the actual ones. Also, even when representing the same part between the drawings, the dimensional relationships and ratios may be represented differently. In particular, several embodiments shown below are examples of devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is not specified by the shape, structure, arrangement, etc. of the components. In the following description, elements having the same function and configuration are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0024] In this embodiment, a biosensor will be described as an example of an electrochemical sensor. A biosensor can detect a specific substance in a biological sample, for example, by using an enzyme and utilizing an electrochemical reaction.

[0025] [1] Configuration of Biosensor 1 FIG. 1 is a plan view of a biosensor 1 according to an embodiment of the present invention. In FIG. 1, the X direction is a direction along one side of the biosensor 1, and the Y direction is a direction orthogonal to the X direction in the plane. FIG. 2 is a cross-sectional view of the biosensor 1 taken along the line A-A' shown in FIG. 1. FIG. 3 is a cross-sectional view of the biosensor 1 taken along the line B-B' shown in FIG. 1. FIG. 4 is a plan view of the electrode pattern extracted from the biosensor 1.

[0026] The biosensor 1 includes an insulating substrate 2, a working electrode 10, a counter electrode 11, a reference electrode 12, wirings 13 to 15, an insulating layer 20, and terminals T1 to T3.

[0027] The insulating substrate 2 is made of an insulating material such as plastic, glass, or ceramic. Examples of the above-mentioned plastic include polyethylene terephthalate (PET), polyester, polystyrene, polypropylene, polycarbonate, polyimide, and acrylic resin.

[0028] An electrode pattern is provided on the insulating substrate 2. In the present embodiment, a plurality of electrodes provided on the insulating substrate 2 are referred to as an electrode pattern. The electrode pattern includes a working electrode 10, a counter electrode 11, and wirings 13 to 15.

[0029] The working electrode 10 is provided on the insulating substrate 2. The working electrode 10 is an electrode for detecting a measurement target. On the working electrode 10, a substance that causes an electrochemical reaction (oxidation and reduction) with the sample solution to be measured is fixed. The working electrode 10 has, for example, a circular shape. The working electrode 10 is made of a conductive material and is made of a metal or a carbon electrode, etc. The carbon electrode is an electrode mainly composed of carbon. Carbon includes carbon black, graphite, and carbon nanotubes. Carbon may be composed of a mixture of carbon black and graphite. The working electrode 10 may be made of a conductive paste containing conductive particles and a binder (resin). From the viewpoints of corrosion resistance and cost, it is desirable that the working electrode 10 be made of a carbon paste. The carbon paste contains, for example, carbon, resin, a curing agent, and a solvent.

[0030] The counter electrode 11 is provided on the insulating substrate 2. The counter electrode 11 is an electrode paired with the working electrode 10 and is an auxiliary electrode for flowing the current generated at the working electrode 10. The counter electrode 11 is arranged adjacent to the working electrode 10. Specifically, the counter electrode 11 is arranged with a space from the working electrode 10 so as to surround a part of the periphery of the working electrode 10. In the present embodiment, the counter electrode 11 is configured to be along approximately half of the periphery of the working electrode 10. The counter electrode 11 can use the same conductive material as the working electrode 10. The counter electrode 11 may use a different conductive material from the working electrode 10.

[0031] On the insulating substrate 2, wirings 13 to 15 are provided. The wirings 13 to 15 are each configured to extend in the Y direction. The wiring 13 is electrically connected to the working electrode 10 and is formed of a continuous layer with the working electrode 10. The wiring 13 is made of the same conductive material as the working electrode 10. The wiring 14 is electrically connected to the reference electrode 12. The wiring 14 is made of the same conductive material as the wiring 13. The wiring 15 is electrically connected to the counter electrode 11. The wiring 15 is formed of a continuous layer with the counter electrode 11. The wiring 15 is made of the same conductive material as the counter electrode 11.

[0032] The reference electrode 12 is arranged adjacent to the working electrode 10. The reference electrode 12 is provided on the end of the wiring 14 and is electrically connected to the wiring 14. The reference electrode 12 has a rectangle extending in the X direction in plan view. The reference electrode 12 is provided on the insulating substrate 2 so as to cover the end of the wiring 14. The reference electrode 12 is an electrode that generates a reference potential. The reference electrode 12 is preferably made of a conductive material and a material with a stable potential when current flows. The reference electrode 12 is, for example, composed of a silver-silver chloride electrode. The silver-silver chloride electrode is composed of a silver-silver chloride paste. The silver-silver chloride paste is a conductive material containing silver particles, silver chloride particles, and a thermoplastic resin.

[0033] An insulating layer 20 is provided on the insulating substrate 2 and the wirings 13 to 15. The insulating layer 20 is made of an insulating material, for example, resin. Examples of the resin include epoxy resin and phenolic resin. The insulating layer 20 is preferably made of a resin that can be formed in a printing process, and preferably made of a thermosetting resin or a UV (ultraviolet) curable resin. The insulating layer 20 includes a first portion 20A and a second portion 20B.

[0034] The first portion 20A of the insulating layer 20 is disposed between the working electrode 10 and the counter electrode 11 and insulates the working electrode 10 from the counter electrode 11. The first portion 20A is provided on the insulating substrate 2 so as to surround the working electrode 10. The first portion 20A has an annular shape. The first portion 20A has a function of preventing a substance fixed on the working electrode 10 from contacting the counter electrode 11.

[0035] The second portion 20B of the insulating layer 20 is provided on the insulating substrate 2 so as to surround the regions where the working electrode 10, the counter electrode 11, and the reference electrode 12 are disposed. The second portion 20B is disposed along the periphery of the insulating substrate 2. The second portion 20B has a rectangular frame shape. The second portion 20B has a function of insulating the working electrode 10, the counter electrode 11, and the reference electrode 12 from the outside of the biosensor 1.

[0036] The insulating layer 20 includes an insulating portion for covering the wirings 13 to 15. The insulating layer 20 exposes the ends of the wirings 13 to 15. The ends of the wirings 13 to 15 exposed from the insulating layer 20 are used as three terminals T1 to T3 of the biosensor 1.

[0037] Next, the configuration of the biosensor 1 in a state where the reagent layer 21 is fixed to the working electrode 10 will be described. FIG. 5 is a plan view of the biosensor 1 including the reagent layer 21. FIG. 6 is a cross-sectional view of the biosensor 1 taken along the line A-A' shown in FIG. 5. FIG. 7 is a cross-sectional view of the biosensor 1 taken along the line B-B' shown in FIG. 5.

[0038] The reagent layer 21 is fixed on the working electrode 10. The reagent layer 21 is a substance that causes an electrochemical reaction (oxidation and reduction) with the sample solution to be measured. The reagent layer 21 is composed of an electron mediator, an enzyme, or the like.

[0039] A protective layer 22 is provided on the reagent layer 21, the counter electrode 11, and the reference electrode 12. The reagent layer 21 is covered with the protective layer 22. The protective layer 22 is configured to be filled inside the second portion 20B of the insulating layer 20. The protective layer 22 is made of, for example, resin. This resin is made of, for example, a water-soluble photosensitive resin. The photosensitive resin is configured to be cured by, for example, ultraviolet irradiation.

[0040] The biosensor 1 is configured as described above. The terminals T1 to T3 of the biosensor 1 are connected to the connector of the electrochemical detection device.

[0041] When the biosensor 1 is in use, a predetermined potential difference is applied between the counter electrode 11 and the working electrode 10 with reference to the potential of the reference electrode 12. The sample solution that has penetrated the protective layer 22 reacts with the reagent layer 21 to generate a target substance. As a result, a current corresponding to the concentration of the target substance flows between the working electrode 10 and the counter electrode 11. The electrochemical detection device can measure the current value flowing between the working electrode 10 and the counter electrode 11 and measure the concentration of the target substance in the sample solution based on the measurement result.

[0042] The biosensor 1 of this embodiment can measure, for example, the blood glucose level or the lactic acid level in a biological sample.

[0043] [2] Manufacturing method Next, the manufacturing method of the biosensor 1 will be described with reference to the drawings. FIG. 8 is a flowchart for explaining the manufacturing method of the biosensor 1.

[0044] First, an insulating substrate 2 is prepared. The insulating substrate 2 is made of, for example, a PET film. Subsequently, a pretreatment is performed on the PET film as the insulating substrate 2 (step S100). Specifically, the insulating substrate 2 is heat-treated (annealed). In this heat treatment, heat equal to or higher than the heat treatment temperature in the subsequent process is applied to the insulating substrate 2 so that the insulating substrate 2 does not change in dimensions due to the heat history in the subsequent process. Subsequently, using a die-cutting blade, holes for printing stage positioning and printing alignment are formed in the insulating substrate 2.

[0045] Subsequently, prepare a screen printing machine for performing screen printing. Alignment pins are provided on the stage of the screen printing machine. Subsequently, insert the holes of the insulating substrate 2 into the pins of the stage, set the insulating substrate 2 on the stage, and vacuum-adsorb the insulating substrate 2 on the stage.

[0046] Subsequently, using the screen printing method, form an electrode pattern on the insulating substrate 2 (step S101). FIG. 9 is a diagram for explaining the process of forming the electrode pattern. FIG. 9(a) shows the printing process, and FIG. 9(b) shows the electrode pattern formed by screen printing. The arrows in FIG. 9 illustrate the printing direction.

[0047] Prepare a screen printing plate 30 with a pattern for the electrode. Using the screen printing plate 30 and the squeegee 31 of the screen printing machine, screen-print a conductive paste onto the insulating substrate 2. As the conductive paste, a carbon paste is used. Thereafter, cure the electrode pattern.

[0048] In the present embodiment, a plurality of biosensors 1 are multi-sidedly attached onto a common insulating substrate 2. FIG. 10 is a diagram for explaining the manufacturing process of the multi-sidedly attached plurality of biosensors 1. The insulating substrate 2 is configured in a sheet shape having an area capable of arranging a plurality of biosensors 1. A plurality of biosensors 1 are arranged, for example, in a matrix shape on the sheet-shaped insulating substrate 2. A sheet composed of the multi-sidedly attached plurality of biosensors 1 is called a multi-sided attachment sheet. Each of the plurality of biosensors 1 is also called an electrode chip.

[0049] Although not shown, a plurality of alignment marks are formed at predetermined positions of the insulating substrate 2. The alignment marks are formed, for example, for each biosensor 1. The alignment marks are made of the same material as the electrode pattern and are used for positioning in the manufacturing process.

[0050] Subsequently, the electrode pattern is partially polished (step S102). The polishing process is performed using a polishing apparatus 40. FIG. 11 is a schematic diagram for explaining the configuration of the polishing apparatus 40. The polishing apparatus 40 includes a stage 41, a polishing film 42, a pay-out section 43, a take-up section 44, and a metal head 45. The arrows in FIG. 11 illustrate the polishing direction.

[0051] A work 46 to be polished is fixed on the stage 41. In the present embodiment, the work 46 is an insulating substrate 2 and an electrode pattern. The polishing film 42 is for polishing the work 46. The pay-out section 43 pays out the polishing film 42, and the take-up section 44 takes up the polishing film 42. The metal head 45 includes a roller and has a function of pressing the polishing film 42 against the work 46. The metal head 45 or the stage is movable in the left-right direction in the figure.

[0052] FIG. 12 is a diagram for explaining the process of polishing the electrode pattern. The arrows in FIG. 12 indicate the polishing direction. The roller or the stage included in the metal head 45 is movable in the direction of the arrow in FIG. 12. FIG. 13 is a diagram for explaining the polishing region 32 of the electrode pattern in the polishing process. In FIGS. 12 and 13, the electrode patterns corresponding to three biosensors are extracted and shown. The number of electrode patterns polished simultaneously can be set as appropriate.

[0053] In the present embodiment, only a part of the electrode pattern is polished. Specifically, only the working electrode 10 and the counter electrode 11 are polished. The wirings 13 to 15 are not polished. By this polishing process, the film thicknesses of the working electrode 10 and the counter electrode 11 become thinner than those of the wirings 13 to 15. Also, the surfaces of the working electrode 10 and the counter electrode 11 are flattened more than the surfaces of the wirings 13 to 15.

[0054] Subsequently, the insulating layer 20 is formed using the screen printing method (step S103). FIG. 14 is a diagram for explaining the process of forming the insulating layer 20. FIG. 14(a) shows the printing process, and FIG. 14(b) shows the insulating layer 20 formed by screen printing. The arrow in FIG. 14 illustrates the printing direction.

[0055] Prepare a screen printing plate 33 with the pattern of the insulating layer 20. Using the screen printing plate 33 and the squeegee 31 of the screen printing machine, an insulating paste is screen printed onto the insulating substrate 2 and the electrode pattern. As the insulating paste, a thermosetting resin or a UV curable resin is used. The insulating paste is preferably a thermosetting type insulating paste that does not contain the main solvent of the carbon paste, or a solvent-free UV curable type insulating paste. As the thermosetting type insulating paste, a material containing an epoxy resin and a curing agent is used. As the UV curable type insulating paste, a material containing an epoxy resin and a photoinitiator is used. Subsequently, the insulating paste is cured. In this curing process, heating or UV irradiation is used. Thereby, an insulating layer 20 (including the first portion 20A and the second portion 20B) is formed on the insulating substrate 2 and the electrode pattern.

[0056] Subsequently, the reference electrode 12 is formed using the screen printing method (step S104). FIG. 15 is a diagram for explaining the process of forming the reference electrode 12. FIG. 15(a) shows the printing process, and FIG. 15(b) shows the reference electrode 12 formed by screen printing. The arrow in FIG. 15 illustrates the printing direction.

[0057] Prepare a screen printing plate 34 with a pattern of the reference electrode 12. Using the screen printing plate 34 and the squeegee 31 of the screen printing machine, screen-print the conductive paste onto the end of the wiring 14. As the conductive paste, a paste mainly composed of silver-silver chloride (silver-silver chloride paste) is used. Subsequently, thermally cure the silver-silver chloride paste. Thereby, the reference electrode 12 is formed on the end of the wiring 14. FIG. 16 is a diagram for explaining the manufacturing process of the plurality of multi-sided biosensors 1 in a state where the reference electrode 12 is formed.

[0058] Subsequently, using the dropping method, a reagent layer 21 is formed on the working electrode 10 (step S105). FIG. 17 is a diagram for explaining the process of forming the reagent layer 21. FIG. 17(a) shows the dropping process, and FIG. 17(b) shows the reagent layer 21 formed by the dropping method. Specifically, the reagent 21A is dropped onto the working electrode 10 using the nozzle 47.

[0059] Subsequently, using the dropping method, a protective layer 22 is formed on the reagent layer 21, the counter electrode 11, and the reference electrode 12 (step S106). FIG. 18 is a diagram for explaining the process of forming the protective layer 22. FIG. 18(a) shows the dropping process, and FIG. 18(b) shows the protective layer 22 formed by the dropping method. Specifically, the insulating material 22A is dropped using the nozzle 47 so as to fill the region inside the second portion 20B of the insulating layer 20. The insulating material 22A is composed of, for example, a water-soluble photosensitive resin. Subsequently, the insulating material 22A is cured. Thereby, the protective layer 22 is formed on the reagent layer 21, the counter electrode 11, and the reference electrode 12.

[0060] FIG. 19 is a diagram for explaining the manufacturing process of the plurality of multi-sided biosensors 1 in a state where the protective layer 22 is formed.

[0061] Subsequently, the plurality of multi-sided bio-sensors 1 are chip-formed (step S107). FIG. 20 is a diagram for explaining the process of chip-forming the bio-sensor 1. FIG. 20(a) shows the plurality of multi-sided bio-sensors 1, and FIG. 20(b) shows the plurality of chip-formed bio-sensors 1. In FIG. 20, two bio-sensors 1 are extracted and shown. Specifically, for example, by dicing, the insulating substrate 2 is divided for each bio-sensor 1. In this way, a plurality of bio-sensors 1 are manufactured.

[0062] [3] Detailed configuration of the electrode pattern Next, the detailed configuration of the electrode pattern in the bio-sensor 1 will be described.

[0063] FIG. 21 is a plan view showing the electrode pattern in the bio-sensor 1 extracted. The electrode pattern is provided on the insulating substrate 2. The electrode pattern has a sensor portion 50 and a non-sensor portion 51. The sensor portion 50 and the non-sensor portion 51 are composed of a continuous layer and are made of the same conductive material. This conductive material is formed of, for example, carbon paste and is a conductive material containing carbon.

[0064] The sensor portion 50 is an electrode that functions as a sensor. In the present embodiment, it consists of a working electrode 10 and a counter electrode 11. The non-sensor portion 51 is an electrode that functions as a wiring and a terminal. In the present embodiment, it consists of wirings 13 to 15. As described above, the sensor portion 50 (the working electrode 10 and the counter electrode 11) is polished, and the non-sensor portion 51 (the wirings 13 to 15) is not polished.

[0065] The surface states of the sensor portion 50 (with polishing) and the non-sensor portion 51 (without polishing) were observed using an optical microscope. Also, the film thicknesses of the sensor portion 50 and the non-sensor portion 51 were measured. The film thickness of the electrode pattern was measured using a step gauge.

[0066] FIG. 22 is a diagram for explaining the film thickness of the sensor unit 50 (with polishing). FIG. 23 is a diagram for explaining the film thickness of the non-sensor unit 51 (without polishing). In FIGS. 22 and 23, the horizontal axis represents the measurement distance (mm), and the vertical axis represents the film thickness (μm). The maximum film thickness of the sensor unit 50 is denoted as TA, and the maximum film thickness of the non-sensor unit 51 is denoted as TB.

[0067] It can be understood from FIG. 22 that the surface of the sensor unit 50 is approximately flat. It can be understood from FIG. 23 that the surface of the non-sensor unit 51 has roughness.

[0068] FIG. 24 is a diagram for explaining the results of measuring the film thickness of the electrode pattern. In FIG. 24, "with polishing" corresponds to the film thickness of the sensor unit 50, and "without polishing" corresponds to the film thickness of the non-sensor unit 51. FIG. 24 shows the film thicknesses at eight arbitrary measurement positions and their average film thickness (Ave.). It can be understood from FIG. 24 that the film thickness of the sensor unit 50 is thinner than that of the non-sensor unit 51.

[0069] Next, the polishing conditions of the electrode pattern were changed, and the surface state and film thickness of the electrode pattern were observed. There are three types of polishing conditions, and the number of polishing times is 10 times, 20 times, and 40 times. The number of polishing times means the rotation of the roller at the polishing location. At each polishing condition, the maximum film thickness TA of the sensor unit 50, the maximum film thickness TB of the non-sensor unit 51, and the film thickness ratio TA / TB between the maximum film thickness TA of the sensor unit 50 and the maximum film thickness TB of the non-sensor unit 51 were measured.

[0070] In addition, the electrochemical characteristics of the biosensor 1 were evaluated. The electrochemical characteristics of the biosensor 1 can be evaluated using the cyclic voltammetry (CV) method. The CV method is performed using a potentiostat. The potentiostat controls the voltage between the working electrode 10 and the reference electrode 12 and measures the current flowing between the working electrode 10 and the counter electrode 11 in a three-electrode system composed of the working electrode 10, the counter electrode 11, and the reference electrode 12. That is, the potential of the working electrode 10 is changed with reference to the potential of the reference electrode 12. When the potential is swept to the negative side, a reduction reaction occurs, and when the potential is swept to the positive side, an oxidation reaction occurs.

[0071] In this embodiment, the peak current value was measured by the CV method, and the electrochemical characteristics of the biosensor 1 were evaluated based on the peak current value. The peak current value means the peak current value in the oxidation reaction. In this embodiment, the peak current value has the same meaning as the oxidation peak current value.

[0072] FIG. 25 is a diagram for explaining the measurement results of the maximum film thicknesses of the sensor portion 50 and the non-sensor portion 51 under a plurality of polishing conditions. In FIG. 25, the maximum film thickness TA after polishing corresponds to the maximum film thickness of the sensor portion 50, and the maximum film thickness TB before polishing corresponds to the maximum film thickness of the non-sensor portion 51.

[0073] As shown in FIG. 25, the film thickness ratio TA / TB at 10 polishing times is 0.68, the film thickness ratio TA / TB at 20 polishing times is 0.60, and the film thickness ratio TA / TB at 40 polishing times is 0.44. As the number of polishing times increases, the film thickness ratio TA / TB decreases.

[0074] In addition, the peak current values under three types of polishing conditions (10, 20, and 40 polishing times) are 22.0 (μA), 23.9 (μA), and 24.1 (μA). As the number of polishing times increases, the peak current value increases. The peak current value at 0 polishing times is 12.3 (μA).

[0075] FIG. 26 is a graph for explaining measurement results under a plurality of polishing conditions. FIG. 26 plots the measurement results of FIG. 25. The horizontal axis of FIG. 26 represents the film thickness ratio TA / TB, and the vertical axis represents the peak current value (μA).

[0076] In FIG. 26, the regression line is represented by "y = -7.7086x + 27.75", and the coefficient of determination is represented by "R 2 = 0.6779". It can be understood from FIG. 26 that there is a relationship between the film thickness ratio TA / TB and the peak current value. As the film thickness ratio TA / TB decreases, the peak current value increases.

[0077] In this embodiment, the peak current value of the biosensor 1 is set to 22 (μA) or more. By satisfying this criterion, the electrochemical characteristics of the biosensor 1 can be improved. The film thickness ratio TA / TB is set so as to satisfy the following relationship. 0.4 ≦ TA / TB ≦ 0.7 By setting the film thickness ratio TA / TB to 0.7 or less, the peak current value of the biosensor 1 can be set to 22 (μA) or more.

[0078] From the measurement results of FIGS. 25 and 26, the average change rates of the film thickness ratio TA / TB and the peak current value in "0 times → 10 times", "10 times → 20 times", and "20 times → 40 times" are as follows. 0 times → 10 times: 30.3 10 times → 20 times: 23.8 20 times → 40 times: 1.3

[0079] As the film thickness ratio TA / TB decreases, the peak current value increases, but as the number of polishing times increases, the increase rate of the peak current value decreases. Even when observing the state of the electrode surface after polishing, at the time of 40 times of polishing, the unpolished area is quite small and almost the entire surface is polished. Therefore, even if polished more than 40 times, the increase amount of the peak current value becomes small, so the effect on the manufacturing cost becomes low. For this reason, it is desirable that the film thickness ratio TA / TB be 0.4 or more.

[0080] [4] Regarding the shape of the step of the electrode pattern Next, the shape of the step between the sensor portion 50 and the non-sensor portion 51 will be described. In the present embodiment, the film thickness of the sensor portion 50 is set to be thinner than the film thickness of the non-sensor portion 51. For this reason, a step is formed at the boundary between the sensor portion 50 and the non-sensor portion 51. Hereinafter, the shape of the step between the sensor portion 50 and the non-sensor portion 51 according to the first to third embodiments will be described.

[0081] FIG. 27 is a partial cross-sectional view for explaining a step 52 between the sensor portion 50 and the non-sensor portion 51 according to the first embodiment. A step 52 is formed at the boundary between the sensor portion 50 and the non-sensor portion 51. The step 52 according to the first embodiment has a substantially right angle in its cross-sectional shape. That is, the step 52 according to the first embodiment has a stepped shape.

[0082] FIG. 28 is a partial cross-sectional view for explaining a step 52 between the sensor portion 50 and the non-sensor portion 51 according to the second embodiment. The step 52 according to the second embodiment is configured such that its cross-sectional shape has an inclination. That is, the cross-sectional shape of the step 52 according to the second embodiment is configured such that the film thickness continuously decreases from the non-sensor portion 51 toward the sensor portion 50.

[0083] FIG. 29 is a partial cross-sectional view for explaining a step 52 between the sensor portion 50 and the non-sensor portion 51 according to the third embodiment. The step 52 according to the third embodiment has a concave curved shape in its cross-sectional shape.

[0084] The shape of the step 52 according to each of the above embodiments can be configured according to the conditions of the polishing process.

[0085] [5] Effects of the embodiment As described in detail above, in this embodiment, the biosensor 1 includes an electrode pattern provided on an insulating substrate 2, and this electrode pattern includes a sensor portion 50 and a non-sensor portion 51 formed of a continuous layer. The sensor portion 50 is an electrode that functions as a sensor and includes a working electrode 10 and a counter electrode 11. The non-sensor portion 51 is an electrode that does not function as a sensor and includes wirings 13 to 15. The film thickness of the sensor portion 50 is set to be thinner than the film thickness of the non-sensor portion 51. Also, the surface of the sensor portion 50 is configured to be flatter than the non-sensor portion 51.

[0086] Therefore, according to this embodiment, the electrochemical characteristics of the biosensor 1 can be improved. Also, the sensitivity of the biosensor 1 can be improved. Also, the rate of the electrochemical reaction in the biosensor 1 can be improved.

[0087] Also, in the CV measurement, the peak current value (oxidation peak current value) of the biosensor 1 can be increased. Thereby, the sensitivity of the biosensor 1 can be improved.

[0088] Also, by polishing the surface of the sensor portion 50, the ratio of the conductive particles exposed on the surface can be increased, and the surface of the sensor portion 50 can be activated. Thereby, the sensitivity of the biosensor 1 can be improved.

[0089] Also, since the film thickness of the non-sensor portion 51 can be increased, the wiring resistance of the non-sensor portion 51 can be reduced. Thereby, the electrical characteristics of the biosensor 1 can be improved.

[0090] Also, only the sensor portion 50 of the electrode pattern can be polished. That is, only the sensor portion 50 can be polished by a desired polishing amount while protecting the alignment mark formed of the same conductive material as the electrode pattern. Thereby, the manufacturing process using the alignment mark can be accurately implemented.

[0091] In addition, it is possible to reduce the contamination of the substrate surface by the abrasive dust generated during polishing and the polishing waste liquid containing the same. Therefore, the cleaning process of the substrate becomes easier, and the manufacturing cost can be reduced.

[0092] Also, using the screen printing process, a plurality of biosensors 1 can be formed in a multi-sided attachment manner. Thereby, the manufacturing cost of the biosensor 1 can be reduced. In addition, mass production of the biosensor 1 becomes possible, and an inexpensive and disposable biosensor 1 can be manufactured.

[0093] In the above embodiment, a biosensor is described as an example of the electrochemical sensor. However, it is not limited to this, and the electrochemical sensor of the present embodiment is also applicable to gas sensors, water quality inspection sensors, soil inspection sensors, residual pesticide detection sensors, and the like.

[0094] The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist thereof at the implementation stage. Also, each embodiment may be implemented in an appropriate combination, and in that case, the combined effects can be obtained. Furthermore, the above embodiment includes various inventions, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, if the problem can be solved and the effect can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention.

Explanation of Reference Numerals

[0095] 1... Biosensor, 2... Insulating substrate, 10... Working electrode, 11... Counter electrode, 12... Reference electrode, 13 - 15... Wiring, 20... Insulating layer, 21... Reagent layer, 22... Protective layer, 30, 33, 34... Screen printing plate, 31... Squeegee, 32... Polishing area, 40... Polishing device, 41... Stage, 42... Polishing film, 43... Pay-out section, 44... Take-up section, 45... Metal head, 46... Workpiece, 47... Nozzle, 50... Sensor section, 51... Non-sensor section, 52... Step, T1 - T3... Terminals.

Claims

1. An insulating substrate, An electrode pattern provided on the insulating substrate, Comprising, The electrode pattern includes a sensor portion and a non-sensor portion formed of a continuous layer, The film thickness of the sensor portion is thinner than the film thickness of the non-sensor portion An electrochemical sensor.

2. When the maximum film thickness of the sensor portion is TA and the maximum film thickness of the non-sensor portion is TB, the film thickness ratio TA / TB satisfies the following relationship 0.4 ≤ TA / TB ≤ 0.7 The electrochemical sensor according to Claim 1.

3. The sensor portion includes a working electrode and a counter electrode provided adjacent to the working electrode, The non-sensor portion includes a first wiring electrically connected to the working electrode and a second wiring electrically connected to the counter electrode The electrochemical sensor according to Claim 1.

4. Further comprising a reference electrode provided adjacent to the working electrode, The non-sensor portion includes a third wiring electrically connected to the reference electrode The electrochemical sensor according to Claim 3.

5. Further comprising an insulating layer that insulates the working electrode and the counter electrode and covers the first wiring and the second wiring The electrochemical sensor according to Claim 3.

6. The sensor portion and the non-sensor portion are formed of a conductive material containing carbon The electrochemical sensor according to Claim 1.

7. Comprising a plurality of electrode chips provided on a sheet-like insulating substrate, Each of the plurality of electrode chips is the electrochemical sensor according to Claim 1 A multi-sided sheet.

8. A step of forming an electrode pattern including a sensor portion and a non-sensor portion formed of a continuous layer on an insulating substrate, A step of polishing the sensor portion to make the film thickness of the sensor portion thinner than the film thickness of the non-sensor portion, A method for manufacturing an electrochemical sensor comprising.

9. When the maximum film thickness of the sensor portion is TA and the maximum film thickness of the non-sensor portion is TB, the film thickness ratio TA / TB satisfies the following relationship 0.4 ≤ TA / TB ≤ 0.7 The method for manufacturing an electrochemical sensor according to Claim 8.

10. The sensor portion includes a working electrode and a counter electrode provided adjacent to the working electrode, The non-sensor portion includes a first wiring electrically connected to the working electrode and a second wiring electrically connected to the counter electrode The method for manufacturing an electrochemical sensor according to Claim 8.

11. Further comprising a step of forming a reference electrode provided adjacent to the working electrode on an end portion of the third wiring included in the non-sensor portion The method for manufacturing an electrochemical sensor according to claim 10.

12. Further comprising the step of forming an insulating layer that insulates the working electrode and the counter electrode and coats the first wiring and the second wiring The method for manufacturing an electrochemical sensor according to claim 10.

13. The sensor portion and the non-sensor portion are composed of a conductive material containing carbon The method for manufacturing an electrochemical sensor according to claim 8.

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