Method for manufacturing electronic components, and chipless RFID

Abstract

This invention provides a method for manufacturing electronic components that can form a low-resistance conductive film on a penetrating substrate using ink that can be ejected by an inkjet head. [Solution] A method for manufacturing an electronic component comprises a printing pattern forming step of ejecting ink containing copper and a dispersion medium onto a substrate using an inkjet head to form a printed pattern, a drying film forming step of drying the printed pattern to form a dried film, and a sintering step of sintering the dried film, wherein the substrate is a permeable substrate into which the dispersion medium permeates, the substrate has heat resistance to the sintering step, the content of the dispersion medium is 40% by mass or more of the total amount of ink, Sw is the mass ratio of the dispersion medium to the total amount of ink, T is the permeation drying time of the dispersion medium onto the substrate (seconds), and θ is the contact angle of the dispersion medium onto the substrate (°), and the following formula I is satisfied. TIFF2026137097000021.tif25169

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing electronic components and chipless RFID. [Background technology]

[0002] In recent years, printed electronics has been attracting attention. Printed electronics can be manufactured without the need for exposure or etching, which are used in conventional printed circuit board manufacturing methods, and without the emission of harmful chemicals. One example is electronic components obtained by drawing conductive ink as wiring patterns on a substrate using existing printing technologies (e.g., inkjet).

[0003] For example, a method for forming a conductive pattern has been disclosed by sintering an ink mixture containing copper nanoparticles, a copper oxidizing agent, and CuH in an air atmosphere (see, for example, Patent Document 1 and Non-Patent Document 1). [Overview of the project] [Problems that the invention aims to solve]

[0004] The present disclosure aims to provide a method for manufacturing electronic components that can form a low-resistance conductive film on a penetrating substrate using an ink that can be ejected by an inkjet head. [Means for solving the problem]

[0005] To address the aforementioned issues, this disclosure provides: A printing pattern formation step involves ejecting ink containing copper and a dispersion medium onto a substrate using an inkjet head to form a printed pattern, A drying film formation step involves drying the printed pattern to form a dried film, A method for manufacturing an electronic component, comprising a sintering step of sintering the dried film, The aforementioned substrate is a permeable substrate through which the dispersion medium penetrates, The substrate has heat resistance to the sintering process, The content of the dispersion medium is 40% by mass or more relative to the total amount of the ink. When Sw is the mass ratio of the dispersion medium to the total amount of ink, T is the penetration and drying time of the dispersion medium into the substrate (seconds), and θ is the contact angle of the dispersion medium with respect to the substrate (°), the following equation I is satisfied.

[0006]

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[0007] According to this disclosure, it is possible to provide a method for manufacturing electronic components in which a low-resistance conductive film can be formed on a penetrating substrate using an ink that can be ejected by an inkjet head. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram illustrating an example of a method for measuring electrical conductivity (IACS). [Figure 2] This graph illustrates an example of the correlation between the ratio (mass ratio) of the dispersion medium content to the total ink volume and IACS. [Figure 3] This graph illustrates an example of the correlation between the penetration drying time of the dispersion medium and IACS. [Figure 4] This graph illustrates an example of the correlation between the contact angle of the dispersion medium with respect to the substrate and IACS. [Figure 5] This graph illustrates an example of the relationship between IACS measured values ​​and IACS predicted values. [Figure 6] This is a schematic diagram illustrating an example of the printing pattern formation process and the drying film formation process in this embodiment. [Figure 7] This is a schematic diagram illustrating an example of the sintering process in this embodiment. [Figure 8] This diagram shows the types and molecular structures of dispersion media. [Figure 9]A diagram plotting the relationship between the density and conductivity of paper for each dispersion medium content ratio. [Figure 10] (A) is an X-ray CT observation image of various papers, (B) is a graph showing the illuminance (256 gradations with white being 0 and black being 256) of the image corresponding to the horizontal axis paper thickness direction of (A) on the vertical axis, and (C) is a graph showing the coefficient of variation of the illuminance corresponding to (B) for each paper.

Mode for Carrying Out the Invention

[0009] Conventionally, for substrates used in printed electronics, PET films, polyimide films, and papers having heat resistance capable of withstanding sintering are often used. However, since PET films and polyimide films are derived from petroleum and do not have biodegradability, there are concerns about the environmental load when they are discarded. Also, although paper is of natural origin and has biodegradability, there is a problem that its resistivity increases compared to PET films, polyimide films, etc.

[0010] The method for manufacturing an electronic component according to this embodiment can sufficiently resolve various concerns in the prior art. More specifically, it is possible to realize a method for manufacturing an electronic component capable of forming a low-resistance conductive film on a permeable substrate that is of natural origin or has biodegradability.

[0011] The details of this embodiment will be described below.

[0012] (Method for Manufacturing an Electronic Component, and Apparatus for Manufacturing an Electronic Component) The method for manufacturing an electronic component according to this embodiment includes a printing pattern forming step, a dry film forming step, and a sintering step, and may include other steps as necessary.

[0013] The apparatus for manufacturing an electronic component according to this embodiment includes a printing pattern forming means, a dry film forming means, and a sintering means, and may include other means as necessary.

[0014] The method for manufacturing electronic components can be preferably carried out using an electronic component manufacturing apparatus.

[0015] In the method for manufacturing electronic components according to this embodiment, the relationship between the dispersion medium contained in the ink and the substrate satisfies the following formula I.

[0016]

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[0017] In the above formula I, Sw is the ratio (mass ratio) of the dispersion medium to the total amount of ink, T is the penetration drying time (seconds) of the dispersion medium to the substrate, and θ is the contact angle (°) of the dispersion medium to the substrate.

[0018] Here, we will explain how to derive the above equation I.

[0019] (Exams A-L) [Ink preparation] As copper, Cu nanoparticles (NPs) were used. The method for preparing these Cu nanoparticles is described in detail in Venkata Abhinav et al., RCS Advances 2015, 5, 63985-64030.

[0020] The copper NP dispersion was washed with an ultrafiltration membrane (CO=100kDa, PES). A copper-containing composition was prepared using diethylene glycol monomethyl ether as the dispersion medium. This composition was filtered through a 1 μm syringe filter, and an ink was prepared by adding 1.6% by mass of hypophosphorous acid (HPA).

[0021] The inks used in tests A to D were prepared so that the dispersion medium content was 70% by mass of the total ink volume, the inks used in tests E to H were prepared so that the dispersion medium content was 55% by mass of the total ink volume, and the inks used in tests I to L were prepared so that the dispersion medium content was 20% by mass of the total ink volume.

[0022] [Preparation of the substrate] For tests A, E, and I, a PVA coating (OK Topcoat+, manufactured by Oji Paper Co., Ltd.) was used as the substrate.

[0023] For tests B, F, and J, oil-resistant paper (FS Oil-Resistant Paper FF, manufactured by Daio Paper Corporation) was used, which employs an oil-resistant agent that does not contain fluorine as a base material.

[0024] For tests C, G, and K, glassine paper (manufactured by PAPER Entrance, model number 55064) was used as the substrate. As its name suggests, glassine paper (glass: glass / ine: like) is translucent and smooth, and is mainly manufactured by mechanically compressing pulp for a long period of time and then super-rolling it. This manufacturing process results in a very dense arrangement of paper fibers, making the paper surface smooth and giving it a certain degree of water and oil resistance. These properties are expected to improve the accuracy of conductive film formation and prevent a decrease in conductive function by preventing the penetration of ink components. In the section on glassine No. 6045 of "JIS P0001: Paper, cardboard and pulp," it is defined as "thin paper manufactured by highly beating chemical pulp and super-finishing."

[0025] For tests D, H, and L, oil-resistant paper (T-8 oil-resistant paper, manufactured by Ishizaki Shoji Co., Ltd.) with an oil-resistant agent containing fluorine as a base was used.

[0026] [Printing using inkjet technology] The ink used in tests A through H was printed using the inkjet method.

[0027] A print head (Ricoh MH5420) used in industrial inkjet printers was employed. The print pattern was a solid image with a recording density of 1200 dpi x 1200 dpi and an image size of 30 mm x 30 mm. It was printed in 2-3 layers to achieve a film thickness of 3 μm. The stage was preheated to a substrate surface temperature of 95°C.

[0028] [Printing using the spin coating method] The ink used in tests I-L was in paste form and was printed using the spin-coating method. Printing was performed on the substrate at 7,000 rpm, with a film thickness of 3 μm after drying and sintering.

[0029] [sintering] A polyimide film (Toray DuPont, Kapton 200H ("Kapton" is a registered trademark)) was applied to the surface of the dried printed material, and after being placed on a hot plate heated to 230°C, a 2 kg weight was immediately placed on top and sintered for 60 seconds to obtain the electronic components for each test.

[0030] The conductivity (IACS: International Annealed Copper Standard) of each obtained electronic component was measured according to the following method. The results are shown in Tables 1 and 2. A higher conductivity indicates the formation of a low-resistance conductive film.

[0031] [Method for measuring electrical conductivity (IACS)] The resistivity test was performed in part according to the four-probe method for conductive plastics as specified in JIS K7194:1994. In the four-probe method, as shown in Figure 1, a current I was passed between A and D using probes A to D placed on the electronic component EC, and the potential difference V between B and C was measured. The sheet resistance ρs was then calculated by multiplying the ratio of these values ​​by a correction coefficient RCF. An RCF of 4.532, which can be obtained even assuming an infinite plane, was used. A simple low-resistivity meter (Loresta MCP-T380, manufactured by Nitto Seiko Analytech Co., Ltd. ("Loresta" is a registered trademark)) and a PSP probe with a pin spacing of 1.5 mm were used.

[0032] Next, the film thickness t of the electronic component was measured by observing the cross-section of the sample. Three cross-sections were measured, and the average value was defined as the film thickness t.

[0033] The volume resistivity ρv and its reciprocal, conductivity, were calculated using equation II below. Note that the conductivity (IACS) is calculated using the international standard for soft copper (volume resistivity 1.7241 × 10⁻¹⁰). -8 The conductivity was calculated assuming a conductivity of 100% (Ωm).

[0034]

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[0035] [Table 1]

[0036] [Table 2]

[0037] Based on the results in Tables 1 and 2, Figure 2 shows the relationship between the ratio (mass ratio) of the dispersion medium to the total amount of ink and IACS. Figure 2 shows a clear negative correlation between the ratio (mass ratio) of the dispersion medium to the total amount of ink and IACS. From this, we hypothesized that components such as hypophosphorous acid, which should normally remain in the ink film, migrate to the substrate as the dispersion medium penetrates, thereby inhibiting sintering, increasing resistance, and reducing the conductivity of the resulting electronic component. Based on this hypothesis, we further investigated the relationship between the dispersion medium and the substrate.

[0038] First, the penetration and drying time T of the dispersion medium was investigated. In this specification, "penetration and drying time T of the dispersion medium" refers to the time (in seconds) it takes for the dispersion medium dropped onto the substrate to disappear from the substrate due to penetration and drying.

[0039] The penetration drying time T of the dispersion medium was measured by taking 1000 frames per second using a high-speed microscope camera (Keyence VW-6000) and observing the time it took for a 30 pL droplet of the dispersion medium dropped onto the substrate to disappear from the substrate. The results are shown in Tables 1 and 2.

[0040] Based on the results in Tables 1 and 2, Figure 3 shows the relationship between the penetration drying time T of the dispersion medium and IACS. Figure 3 shows a negative correlation between the penetration drying time T of the dispersion medium and IACS.

[0041] Next, to confirm the more microscopic interactions between the substrate and the dispersion medium, the contact angle θ of the ink with respect to the substrate was measured using a contact angle meter (DMs-301, manufactured by Kyowa Interface Science Co., Ltd.). The droplet sizes were 0.5 μL to 0.6 μL. The results are shown in Tables 1 and 2.

[0042] Based on the results in Tables 1 and 2, Figure 4 shows the relationship between the ink contact angle θ with respect to the substrate and IACS. Figure 4 shows a negative correlation between the ink contact angle θ with respect to the substrate and IACS.

[0043] In addition to the above, we also examined the correlation between the dispersion medium and the surface roughness of the substrate, and the correlation between the dispersion medium and the thickness of the substrate, but we could not confirm a correlation with IACS. Here, using the measurement results obtained in tests A to L, we performed multiple regression analysis with the dispersion medium content ratio Sw (mass ratio) in the total amount of ink, the penetration drying time T (seconds) of the dispersion medium, and the contact angle θ (°) as explanatory variables X. The results are shown in Table 3. The multiple regression analysis shown in Table 3 satisfies the following conditions, indicating that the analysis is statistically correct. • The corrected R² is 0.6 or greater. • The significance level F is 0.05 or less. • The absolute value of the t-value excluding the intercept is 2 or greater. • The p-value is 0.05 or less (excluding the intercept).

[0044] [Table 3]

[0045] In Table 3, X value 1 is the mass ratio of the dispersion medium content in the total amount of ink, X value 2 is the common logarithm of 1 / the penetration and drying time T (seconds) of the dispersion medium, and X value 3 is the contact angle θ (°).

[0046] From the results in Table 3, we obtained Equation III, a predictive formula that can predict conductivity from the mass ratio of the dispersion medium in the total amount of ink, the penetration and drying time of the dispersion medium T (seconds), and the contact angle θ (°).

[0047]

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[0048] Figure 5 shows the relationship between the measured values ​​obtained in the above tests A to L and the predicted values ​​calculated by Equation III. From Figure 5, it can be seen that the conductivity can be predicted with almost accuracy using the prediction formula Equation III.

[0049] For typical electronic components, an IACS of 10% or more is considered sufficient for proper functioning. Therefore, by setting the left-hand side of equation III above to 10% or more and rearranging the equation, we derive equation I below.

[0050]

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[0051] <Printing pattern formation process and printing pattern formation means> The printing pattern formation process involves dispensing an ink containing copper and a dispersion medium onto a substrate to form a printing pattern.

[0052] The printing pattern forming means is a means for forming a printing pattern by ejecting an ink containing copper and a dispersion medium onto a substrate.

[0053] The printing pattern formation process can be suitably carried out by printing pattern forming means.

[0054] <<Base>> The substrate in this embodiment has heat resistance to the sintering process. Furthermore, the substrate in this embodiment is a permeable substrate into which the dispersion medium penetrates. Preferably, this substrate is biodegradable and of natural origin.

[0055] In this specification, "penetrating substrate" refers to a substrate that has a water absorption rate (unit: mass%) of 0.2 or higher according to the ASTM D570 test method.

[0056] In this specification, "biodegradability" refers to the property of being broken down to the molecular level by the action of microorganisms, ultimately becoming carbon dioxide and water, which then recirculate into the natural environment.

[0057] In this specification, "heat resistance to the sintering process" means that the substrate does not deform at the ink's sintering temperature. No deformation means that the change in the substrate's area ratio is within 10%. Furthermore, it is preferable that the substrate's glass transition temperature is higher than the ink's sintering temperature.

[0058] The substrate material is not particularly limited as long as it satisfies the relationship with the dispersion medium in the above formula I, and can be appropriately selected according to the purpose. Examples include paper, cellophane, glass, and heat-resistant synthetic resins. Among these, a cellulose-based substrate is preferred from the viewpoint of environmental impact. The glass transition temperature of cellulose is 300°C.

[0059] In this specification, "cellulose-based substrate" refers to a substrate whose main component is cellulose. In this specification, "main component" refers to a component that accounts for 95% or more of the total amount of the substrate. There are no particular restrictions on the cellulose-based substrate, and it can be appropriately selected depending on the purpose, such as paper and cellophane.

[0060] There are no particular restrictions on the type of paper used; it can be selected appropriately depending on the purpose. Examples include glassine paper, coated paper, and wrapping paper. Among these, glassine paper is particularly preferred. By using glassine paper, a conductive film with lower resistance can be formed compared to other types of paper.

[0061] The paper has no surface coating and preferably has a density of 0.5 g / cm³. 3 More than 1.5g / cm 3 The following, and more preferably, 0.7 g / cm³ 3 More than 1.4g / cm 3 The following, and more preferably 1.0 g / cm³ 3 More than 1.3g / cm 3 The following applies:

[0062] Paper that satisfies the condition of having a density of 0.5 g / cm 3 or more and 1.5 g / cm 3 or less includes glassine paper, oil-resistant paper using a non-fluorine-containing oil-resistant agent, oil-resistant paper using a fluorine-containing oil-resistant agent, and the like. Paper that satisfies the condition of having a density of 1.0 g / cm 3 or more and 1.3 g / cm 3 [[ID=ID=10]]or less includes glassine paper.

[0063] When the density is 0.5 g / cm 3 or more, the fibers constituting the paper are arranged moderately densely, so that when the ink lands, it is possible to suppress the excessive penetration and embedding of copper particles into the fiber gaps (inside) of the paper. As a result, copper particles efficiently remain on the surface of the substrate, and it becomes easy to form a good conductive path after sintering. On the other hand, when the density is 1.5 g / cm 3 or less, the penetration of the dispersion medium is not excessively inhibited, and the penetration drying time T in the above formula I can be appropriately controlled, so that a dry film can be formed while preventing ink bleeding. By these means, an electronic component having a higher conductivity (IACS) can be obtained.

[0064] There is no particular limitation on the heat-resistant synthetic resin, and it can be appropriately selected according to the purpose. For example, polyimide, epoxy resin, polycarbonate, fluororesin, and the like can be mentioned.

[0065] There is no particular limitation on the shape of the substrate, and it can be appropriately selected according to the purpose. For example, flat plate shape, three-dimensional shape, film shape, and the like can be mentioned.

[0066] There is no particular limitation on the size, structure, and thickness of the substrate, and it can be appropriately selected according to the application.

[0067] From the viewpoint of removing deposits, oils and fats, etc., the substrate may be washed with pure water, a neutral detergent, etc. before applying the ink in the printing pattern formation process. There is no particular limitation on the washing method, and it can be appropriately selected according to the purpose. For example, an ultrasonic device may be used in combination.

[0068] The substrate may be surface-treated before the ink is applied in the printing pattern formation process, in order to improve adhesion with the ink. Examples of surface treatment methods include UV / O3 treatment and atmospheric pressure plasma treatment.

[0069] In the printing pattern formation process, it is preferable to heat the printing pattern. Specifically, it is preferable to heat the substrate while ejecting the ink from the inkjet head. In other words, the substrate may be preheated when applying ink to it. Doing so can accelerate the drying of the printing pattern applied to the substrate. Heating the printing pattern during the printing pattern formation process also corresponds to drying the printing pattern to form a dried film in the drying film formation process described later.

[0070] The printed pattern is heated by a heating means. There are no particular restrictions on the heating means, and it can be appropriately selected according to the purpose. For example, a heating mechanism for the stage in a printed pattern forming means can be used.

[0071] There are no particular restrictions on the heating temperature of the substrate, and it can be appropriately selected according to the purpose, but 50°C to 120°C is preferred, and 70°C to 100°C is more preferred.

[0072] If the heating temperature of the substrate is within these ranges, the oxidizing and reducing agents contained in the ink will decompose, which can eliminate problems such as the sintering reaction not proceeding efficiently in the subsequent sintering process.

[0073] As the substrate, you may use one that you have synthesized as appropriate, or you may use a commercially available product.

[0074] Examples of commercially available substrates include oil-resistant paper using fluorine-free oil-resistant agents (Daio Paper Corporation, FS Oil-Resistant Paper FF), glassine paper (PAPER Entrance Co., Ltd., model number 55064), oil-resistant paper using fluorine-containing oil-resistant agents (Ishizaki Shoji Co., Ltd., Oil-Resistant Paper T-8), and oxygen / water vapor barrier paper (Nippon Paper Industries Co., Ltd., Shield+).

[0075] <<Ink>> The ink contains copper and a dispersion medium, and may optionally contain reducing agents, oxidizing agents, and other components.

[0076] -copper- There are no particular restrictions on the shape of the copper; it can be appropriately selected according to the purpose, and it may be fixed in shape or irregular in shape. Among these, a fixed shape is preferred. If the copper is fixed in shape, it is preferably spherical. If the shape of the copper is spherical, it is preferably granular.

[0077] There are no particular restrictions on the particle size (volume-average median diameter) of particulate copper (hereinafter sometimes referred to as "copper particles"), and it can be appropriately selected according to the purpose, but it is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 200 nm.

[0078] There are no particular restrictions on the method for measuring particle size, and it can be appropriately selected depending on the purpose. For example, it can be measured using a particle size distribution analyzer that uses light scattering or a centrifugal sedimentation type particle size distribution analyzer.

[0079] There are no particular restrictions on the copper content, and it can be appropriately selected depending on the purpose, but it is preferable that it be between 10% by mass and 60% by mass relative to the total amount of ink.

[0080] There are no particular restrictions on the method for measuring copper content, and it can be appropriately selected depending on the purpose. For example, it can be measured by simultaneous thermogravimetric-differential thermal analysis (TG-DTA).

[0081] Copper may be synthesized as appropriate, or commercially available copper may be used. There are no particular restrictions on the method of copper synthesis, and it can be selected as appropriate depending on the purpose. For example, it may be synthesized according to the description in Venkata Abhinav et al., RCS Advances 2015, 5, 63985-64030.

[0082] -Dispersion medium- As for the dispersion medium, there are no particular restrictions as long as it does not significantly alter the copper and substrate, and it can be appropriately selected according to the purpose. For example, water, terpineol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, ethylene glycol monohexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol Examples include ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, ethylene glycol monobenzyl ether acetate, ethylene glycol monohexyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monohexyl ether acetate, propylene glycol, dipropylene glycol monomethyl ether, and tripropylene glycol monomethyl ether.

[0083] These can be used individually or in combination of two or more.

[0084] The dispersion medium content is 40% by mass or more, preferably 40% to 99% by mass, and more preferably 50% to 90% by mass, relative to the total amount of ink. If the dispersion medium content is less than 40% by mass relative to the total amount of ink, the viscosity of the ink becomes high, leading to problems such as difficulty in ejection by the inkjet head. If the dispersion medium content is 40% to 60% by mass relative to the total amount of ink, the resistance of the conductive film can be reduced. If the dispersion medium content is 60% to 80% by mass relative to the total amount of ink, the particle ratio becomes smaller, improving ejection stability and being advantageous for forming fine conductive circuits.

[0085] -Reducing agent- There are no particular restrictions on the reducing agent, and it can be appropriately selected depending on the purpose. Examples include copper hydride (CuH) and amine compounds.

[0086] Copper hydride (CuH) only needs to be present in a portion of the copper, and it reduces copper oxide contained in the ink and copper oxide generated during the sintering process. Specifically, during the sintering process, the copper oxide contained in the dried film is reduced by the decomposition of copper hydride (CuH), which facilitates the sintering of copper and allows for the production of electronic components with low-resistance conductive films. Although copper hydride (CuH) is also generated during the sintering process by hypophosphorous acid, its pre-inclusion in the ink promotes the reduction reaction of copper oxide.

[0087] There are no particular restrictions on the copper content containing copper hydride (CuH), and it can be appropriately selected depending on the purpose. However, from the viewpoint of obtaining film thickness by inkjet, which is a non-contact coating method, it is preferable that the content be 20% by mass or more and 60% by mass or less of the total amount of ink.

[0088] As the copper hydride (CuH), commercially available products may be used as appropriate. Alternatively, the copper hydride (CuH) may be synthesized with reference to Non-Patent Document 1, etc.

[0089] Examples of amine compounds include 2-amino-1-butanol, 1-amino-2-propanol, 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diamino-2-propanol, 1-amino-2-butanol, and 2-aminoethanol.

[0090] These can be used individually or in combination of two or more.

[0091] -Oxidizing agent- There are no particular restrictions on the oxidizing agent, and it can be appropriately selected depending on the purpose. Examples include phosphorus-containing compounds. Examples of phosphorus-containing compounds include phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphate, tripolyphosphate, tetrapolyphosphate, trimetaphosphate, polyphosphate, and phosphoric anhydride. Among these, hypophosphorous acid is preferred.

[0092] These can be used individually or in combination of two or more.

[0093] Hypophosphorous acid oxidizes the copper contained in the ink. When hypophosphorous acid is present in the ink, copper hydride (CuH) is generated during the sintering process, and further decomposition of copper hydride (CuH) produces hydrogen, thus accelerating the reduction reaction of copper oxide.

[0094] There are no particular restrictions on the amount of hypophosphorous acid, and it can be appropriately selected depending on the purpose, but it is preferable that the weight ratio of hypophosphorous acid to copper is 0.5% by mass or more and 80% by mass or less.

[0095] As hypophosphorous acid, you may use one that has been synthesized as appropriate, or you may use a commercially available product.

[0096] Examples of commercially available hypophosphorous acid include hypophosphorous acid solutions (manufactured by Sigma-Aldrich and Nippon Chemical Industrial Co., Ltd.).

[0097] There are no particular restrictions on the printing pattern formation method or means, and they can be appropriately selected according to the purpose. However, the inkjet method is preferred from the viewpoint of being able to form a variety of printing patterns without using a plate, and from the viewpoint of enabling efficient and on-demand manufacturing without plates, with fewer consumables.

[0098] When using an inkjet method as a printing pattern formation method or means, the viscosity of the ink is preferably 4 mPa·s to 30 mPa·s, and more preferably 10 mPa·s to 15 mPa·s, from the viewpoint of ejection stability.

[0099] There are no particular limitations on the patterns formed by the printing pattern forming means, and they can be appropriately selected depending on the application. Examples include solid films, electrode patterns, geometric patterns, lines, letters, numbers, symbols, and electrical circuits.

[0100] <Drying film formation process and drying film formation means> The drying film formation process is the process of drying the printed pattern to form a dried film.

[0101] The drying film forming means is a means of forming a dried film by drying the printed pattern.

[0102] The drying film formation process can be suitably carried out by a drying film formation means.

[0103] The drying film formation process is a process of drying the dispersion medium contained in the printed pattern to the extent that the oxidizing agent and reducing agent do not evaporate.

[0104] The drying temperature, which is used to "dry the oxidizing agent and reducing agent to the extent that they do not evaporate," can be set appropriately depending on the type of oxidizing agent and reducing agent, the dispersion medium, and the film thickness of the printed pattern, but is preferably 50°C to 120°C, and more preferably 70°C to 100°C. The drying time, which is used to "dry the oxidizing agent and reducing agent to the extent that they do not evaporate," can be set appropriately depending on the type of oxidizing agent and reducing agent, the dispersion medium, and the film thickness of the printed pattern, but is preferably 1 minute to 30 minutes, and more preferably 1 minute to 5 minutes.

[0105] Setting the temperature and time in the drying film formation process within these ranges prevents the evaporation of oxidizing and reducing agents contained in the ink, thereby efficiently promoting the reduction reaction in the subsequent sintering process.

[0106] The drying film formation process may be carried out in parallel with the printing pattern formation process. The printing pattern may be dried by heating it during the printing pattern formation process. The method for heating the printing pattern during the printing pattern formation process is as previously described in <Printing Pattern Forming Process and Printing Pattern Forming Means>.

[0107] There are no particular restrictions on the means for forming the drying film, and they can be appropriately selected depending on the substrate used and the application. Examples include a clean oven and a hot plate.

[0108] <Sintering process and sintering means> The sintering process is the process of sintering a dried film.

[0109] The sintering means is a means for sintering a dried film.

[0110] The sintering process can be preferably carried out by a sintering means.

[0111] In the sintering process, heating at a temperature higher than the heating temperature in the drying film formation process alters the crystal structure of the conductive metal contained in the ink, causing it to sinter and exhibit conductivity.

[0112] As for the sintering means, there are no particular restrictions as long as it can sinter a dry film, and it can be appropriately selected according to the purpose. For example, the same apparatus as the dry film forming means can be used.

[0113] For example, when using a hot plate as a sintering method, the dry film can be sintered by placing it on a hot plate heated to a predetermined temperature. Pressing with a hot press or hot roller may also be used as appropriate.

[0114] There are no particular restrictions on the sintering temperature in the sintering process, and it can be appropriately selected according to the purpose, but a temperature of 200°C to 300°C is preferred, and a temperature of 200°C to 250°C is more preferred.

[0115] There are no particular restrictions on the sintering time in the sintering process, and it can be appropriately selected according to the purpose, but it is preferably between 1 minute and 30 minutes, and more preferably between 1 minute and 5 minutes.

[0116] The sintering process may be carried out in a sealed and confined space.

[0117] When a dried film is sintered in a sealed state, the reducing agent contained in the dried film evaporates and fills the sealed container, while also remaining on the substrate surface, allowing the reduction reaction to proceed efficiently. Due to the efficient progress of the reduction reaction, sintering can be completed at low temperatures (e.g., 200°C to 250°C) and in a short time (e.g., 10 minutes or less).

[0118] The sintering process preferably involves sintering a sealed container containing a dried film in a chamber where the internal space is under an inert gas atmosphere. This configuration helps to suppress unwanted oxidation that occurs during the sintering process.

[0119] There are no particular restrictions on the inert gas used; it can be appropriately selected depending on the purpose. Examples include N2 gas and Ar gas.

[0120] Here, a method for manufacturing electronic components according to this embodiment will be described with reference to the drawings. However, this embodiment is not limited in any way to these embodiments.

[0121] In addition, the same reference numeral is used for identical components in each drawing, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the components are not limited to this embodiment, and can be set to a number, position, shape, etc. that is preferable for carrying out this embodiment.

[0122] Figure 6 is a schematic diagram illustrating an example of the printing pattern formation process and the drying film formation process in this embodiment. Figure 7 is a schematic diagram illustrating an example of the sintering process in this embodiment.

[0123] The electronic component manufacturing apparatus 100 shown in Figure 6 includes a heater 3 and an inkjet head 4.

[0124] As shown in Figure 6, an inkjet head 4, acting as a printing pattern forming means, applies ink 20 containing copper particles 21 to the substrate 1 to form a printed pattern. At this time, heating may also be performed from the opposite side of the surface to which the printed pattern is applied using a heater 3, acting as a heating means (Figures 6(A), (B)). The substrate 1 may also be heated before the ink 20 is applied to it. As a result, the printed pattern is dried and the first layer of dried film 22 is formed (Figure 6(C)).

[0125] The above series of operations can be repeated as needed to form a printed material 6 with the desired thickness (Figures 6(D), (C)).

[0126] As shown in Figure 7, the printed material 6 is pressed and sintered by a heat press machine 5, which also serves as a sintering means, to form the electronic component 23 (Figures 7(A) to (C)).

[0127] [Application] The electronic components obtained by the manufacturing method of the electronic components according to this embodiment can be suitably used in RFID (Radio Frequency Identification), including chipless applications.

[0128] RFID is an automated identification technology that reads and writes information to tags using wireless communication. RFID tags, which integrate an IC chip and antenna, store information. A reader reads this information, and a system processes and utilizes the data. It is used in a wide range of fields, including logistics, manufacturing, and retail. The IC chip stores information (such as product codes) and responds to radio waves received from the reader. This technology allows for the high-speed, mass production of antenna units.

[0129] On the other hand, chipless RFID does not have an IC chip. IC tags using semiconductor chips have the challenge of high costs due to the chip and substrate mounting. Inkjet printing, which does not require a printing plate, is very suitable for manufacturing countless pattern circuits with countless high-frequency absorption characteristics.

[0130] In all cases, high conductivity of the antenna wiring is crucial for high-frequency reception performance.

[0131] Furthermore, widespread use raises concerns about disposal issues after use, and from an environmental perspective, plant-derived, biodegradable substrates are desired. Biodegradable substrates can be decomposed in soil and composted. [Examples]

[0132] The embodiment will be specifically described below with reference to examples and comparative examples, but the embodiment is not limited to these examples. In the following examples and comparative examples, unless otherwise specified, "%" refers to "mass%".

[0133] (Example 1) <Ink preparation> As copper, Cu nanoparticles (NPs) were used. The method for preparing these Cu nanoparticles is described in detail in Venkata Abhinav et al., RCS Advances 2015, 5, 63985-64030.

[0134] The copper NP dispersion was washed with an ultrafiltration membrane (CO=100kDa, PES). Diethylene glycol monomethyl ether was used as the dispersion medium so that the final dispersion medium content was 70% by mass relative to the total amount of ink, and a composition containing 28.4% by mass of copper was prepared. This composition was filtered through a 1 μm syringe filter, and 1.6% by mass of hypophosphorous acid (HPA) was added to prepare the ink.

[0135] The viscosity of the ink with a dispersion medium content of 0.7 was 10.2 mP·s, measured using a rotational viscometer. Here, a dispersion medium content of 0.7 indicates that the dispersion medium content is 70% by mass of the total ink volume. The same description applies to dispersion medium content values ​​for other values.

[0136] When the obtained ink was analyzed by ion chromatography and X-ray diffraction, a peak for hypophosphorous acid was detected by ion chromatography, and a broad peak for CuH was detected by X-ray diffraction.

[0137] <Preparation of the substrate> Oil-resistant paper (FS Oil-Resistant Paper FF, manufactured by Daio Paper Corporation) using an oil-resistant agent that does not contain fluorine as a base material was used.

[0138] [Printing using inkjet technology] The print pattern was created using inkjet technology.

[0139] A Ricoh MH5420 inkjet head was used. The print pattern was a solid image with a recording density of 1200 dpi x 1200 dpi and an image size of 30 mm x 30 mm. It was printed in 2-3 layers to achieve a film thickness of 3 μm. The stage was preheated to a substrate surface temperature of 95°C to dry the print pattern while ejecting ink.

[0140] <Sintering> A polyimide film (manufactured by Toray DuPont, Kapton 200H ("Kapton" is a registered trademark)) was applied to the surface of the dried printed material, and after being placed on a hot plate heated to 230°C, a 2 kg weight was immediately placed on top and sintered for 60 seconds to obtain the electronic component of Example 1.

[0141] In Example 1, the biodegradability of the substrate, the heat resistance of the substrate, the contact angle θ (°) of the ink with respect to the substrate, the penetration and drying time T (seconds) of the dispersion medium, and the conductivity (IACS) (%) of the obtained electronic component were measured by the following method. The results are shown in Table 4.

[0142] [Method for determining the biodegradability of the substrate] A substrate was judged to be biodegradable and marked with "○" if it was confirmed that the biodegradable resin content was 95% or more by mass of the total substrate and the non-biodegradable resin content was not 5% or more by mass of the total substrate. In other words, FS oil-resistant paper FF was judged to be "○". Similarly, glassine paper (manufactured by PAPER Entrance, model number 55064), oil-resistant paper using a fluorine-containing oil repellent (manufactured by Ishizaki Shoji, oil-resistant paper T-8), oxygen / water vapor barrier paper (manufactured by Nippon Paper Industries, Shield+), PVA coating (manufactured by Oji Paper, OK Topcoat+), PLA film (manufactured by Sewa Film Group, PLA), and PVA film (manufactured by Kuraray, PVA) used in subsequent examples were also judged to be "○". Although oil-resistant paper T-8 contains a fluorine-based oil repellent, fluorine was detected at a level of 1% or less by EDS analysis (energy-dispersive X-ray spectroscopy), so it was judged that cellulose is the main component. Oil-resistant paper and oxygen / water vapor barrier paper are types of packaging paper. PVA, which is petroleum-derived but also known as a component of laundry starch, is water-soluble and has rare biodegradability, and PLA, made from corn and other materials, is hydrolyzed by moisture in the environment to become low-molecular-weight, and ultimately decomposed into carbon dioxide and water by microorganisms, are both marked with a "○". PVA film and PLA film are films made from non-heat-resistant synthetic resins.

[0143] The polyimide used in the following comparative examples (manufactured by Toray DuPont, Kapton H ("Kapton" is a registered trademark)) is a petroleum-derived resin and was judged to be non-biodegradable, hence the "×" mark.

[0144] [Method for evaluating the heat resistance of the substrate] In the above-mentioned sintering process, the shape of the substrate before and after sintering was visually observed and evaluated based on the following evaluation criteria. -Evaluation Criteria- ○: No deformation of the substrate is observed even after sintering. ×: Deformation of the substrate is observed after sintering.

[0145] [Method for measuring the penetration drying time T of a dispersion medium] The penetration drying time T of the dispersion medium was measured by taking 1000 frames per second using a high-speed microscope camera (Keyence VW-6000) and observing the time it took for a 30 pL droplet of the dispersion medium dropped onto the substrate to disappear from the substrate. The results are shown in Table 4.

[0146] [Method for measuring the contact angle θ of ink with respect to the substrate] The contact angle θ of the ink with respect to the substrate was measured using a contact angle meter (DMs-301, manufactured by Kyowa Interface Science Co., Ltd.). The droplet size was 0.5 μL to 0.6 μL. The results are shown in Table 4.

[0147] [Method for measuring electrical conductivity (IACS)] The resistivity test was performed in part according to the four-probe resistivity test method for conductive plastics specified in JIS K7194:1994. As shown in Figure 1, a current I was passed between A and D at probes A to D placed on the electronic component EC, and the potential difference V between B and C was measured. The sheet resistance ρs was determined by multiplying the ratio by a correction coefficient RCF. RCF of 4.532, which can be obtained even assuming an infinite plane, was used. A simple low-resistivity meter (Loresta MCP-T380, manufactured by Nitto Seiko Analytech Co., Ltd. ("Loresta" is a registered trademark)) and a PSP probe with a pin spacing of 1.5 mm were used.

[0148] Next, the film thickness t of the electronic component was measured by observing the cross-section of the sample. Three cross-sections were measured, and the average value was defined as the film thickness t.

[0149] The volume resistivity ρv and its reciprocal, conductivity, were calculated using equation II below. Note that the conductivity (IACS) is calculated using the international standard for soft copper (volume resistivity 1.7241 × 10⁻¹⁰). -8 The conductivity was calculated with Ωm set to 100%. The results are shown in Table 4. IACS determined that a value of 10% or higher was usable.

[0150]

number

[0151] (Examples 2-6 and Comparative Examples 1-14) As shown in Tables 4 to 8 below, the electronic components of Examples 2 to 6 were manufactured in the same manner as in Example 1, except that the ratio (mass ratio) of the dispersion medium to the total amount of ink and the type of substrate were changed, and each was evaluated.

[0152] The viscosity of the ink with a dispersion medium content of 0.55 was 14.5 mP·s, and was measured using a rotational viscometer.

[0153] The viscosity of the ink with a dispersion medium content of 0.2% was 10,000 mP·s, and was measured using a rotational viscometer. The ink with a dispersion medium content of 0.2% was printed using the spin-coating method. Specifically, it was printed onto a substrate at 7,000 rpm, with a film thickness of 3 μm after drying and sintering.

[0154] The substrates used were one of the following: oil-resistant paper using a fluorine-free oil-resistant agent (Daio Paper Corporation, FS Oil-Resistant Paper FF), glassine paper (PAPER Entrance Co., Ltd., model number 55064), oil-resistant paper using a fluorine-containing oil-resistant agent (Ishizaki Shoji Co., Ltd., Oil-Resistant Paper T-8), oxygen / water vapor barrier paper (Nippon Paper Industries Co., Ltd., Shield+), PVA coating (Oji Paper Co., Ltd., OK Topcoat+), polyimide (Toray DuPont, Kapton H ("Kapton" is a registered trademark)), PLA film (Sewa Film Group Co., Ltd., PLA), and PVA film (Kuraray Co., Ltd., PVA). Note that Kapton H, PLA film, and PVA film are non-permeable substrates, while the other substrates used in the experiments are permeable substrates.

[0155] The paper used in the experiment was FS oil-resistant paper FF (density: 0.89 g / cm³). 3 ), glassine paper (density: 1.17 g / cm³) 3 ), oil-proof paper T-8 (density: 0.79g / cm 3 ), OK Top Coat + (Density: 1.24 g / cm³) 3 ) was.

[0156] Comparative Examples 9-14, shown in Table 8, had a dispersion medium content ratio of 0.2 (dispersion medium was 20% by mass of the total ink volume), and all of them had high viscosity, making ejection by the inkjet head impossible.

[0157] (Examples 7-10) As shown in Tables 9-10 below, the electronic components of Examples 7-10 were manufactured in the same manner as in Example 1, except that the type of dispersion medium, the content ratio (mass ratio) of the dispersion medium to the total amount of ink, and the type of substrate were changed, and each was evaluated.

[0158] The types and viscosities of the dispersion media are shown below. These were selected because they are widely used in paints and inks due to their dissolving power and volatility, and because they are relatively low in toxicity and safe. Their molecular structures are shown in Figure 8.

[0159] Examples 1-6: Diethylene glycol monomethyl ether (4.1 mP·s) Examples 7-8: Propylene glycol monomethyl ether (1.7 mP·s) Examples 9-10: Ethylene glycol dimethyl ether (0.5 mP·s) Here, by using a lower viscosity dispersion medium, the viscosity was reduced to allow inkjet ejection even with a lower dispersion medium content compared to Examples 1-6. The viscosity of the ink was 12.1 mP·s in Examples 7-8 with a dispersion medium content ratio of 0.45, and 13.3 mP·s in Examples 9-10 with a dispersion medium content ratio of 0.4. All values ​​were measured using a rotational viscometer.

[0160] Glassine paper was considered particularly advantageous in IACS due to its high density, which is achieved through ultra-rolling during manufacturing. The evaluation results are shown in Table 11. In Table 11, electronic components were manufactured and evaluated in the same manner as in Example 1, except that the ratio of dispersion medium content (mass ratio) to the total amount of ink and the type of substrate were changed. Here, density was calculated by cutting each sheet of paper, which had been conditioned at 23°C and 50% RH for 24 hours, into 39.1 mm squares, and measuring the weight (precision balance) and thickness (micrometer).

[0161] We have added experimental results using glassine window envelopes (Hart Co., Ltd., model number MR1128, laser printer compatible glassine window envelope, long size 3), which were expected to have a higher density due to their transparency requirements within the glassine paper.

[0162] Figure 9 shows a plot of the relationship between paper density and conductivity for each dispersion medium content ratio. Figure 9 plots the results from Table 11, with density on the horizontal axis and conductivity on the vertical axis. Except for OK Topcoat+, a trend in density and conductivity can be observed. OK Topcoat+ is a type of coated paper, made by applying a coating to high-quality or medium-quality paper as a base. Coated paper can be broadly classified according to the base paper and coating amount, as shown in Table 12. OK Topcoat+ is A2 coated, with a coating amount of 15 g / m². 2 Therefore, to achieve the desired density of the base paper, the amount of coating agent applied must be considered.

[0163] To understand the condition of the coating layer, observation was performed using X-ray CT (Carl Zeiss Xradia 510 Versa, light source applied voltage / output 60kV / 5W, pixel size 0.99μm). Five types of paper were layered and attached to polystyrene foam, then secured with cellophane tape. Figure 10(A) is an observation image of the coating layer, Figure 10(B) is a graph showing the illuminance of the image (256 levels, with white being 0 and black being 256) on the vertical axis, corresponding to the paper thickness direction on the horizontal axis of Figure 10(A), and Figure 10(C) is a graph showing the coefficient of variation of illuminance for each type of paper, corresponding to Figure 10(B). The coefficient of variation is calculated by dividing the standard deviation by the mean, and is a statistical indicator used to compare variability.

[0164] The coating layer of OK Topcoat+ (with coating layers on both sides) has a different illuminance than the cellulose fiber portion, and its coefficient of variation is 0.0187, which is clearly larger than the others. Using the coefficient of variation value of OK Topcoat+, the coefficient of variation of single-sided coated paper (with a coating layer on only one side) is calculated to be 0.0154. The coefficient of variation of other paper types without a coating layer ranges from 0.0073 to 0.0090, which is smaller than that of paper types with a coating layer.

[0165] Figure 10(A) shows an image with a pixel size of 0.99 μm, sliced ​​at a depth of 0.99 μm. In both types of glassine, only a small portion of the cellulose fiber boundaries are observed, confirming a unique, densely compressed structure. This nearly uniform structure is likely to result in high light transmittance.

[0166] These analyses revealed that coated paper and other papers have different cross-sectional structures, and that for paper types with a nearly uniform cross-sectional structure, Figure 9 shows a high correlation between density and conductivity. In particular, high-density papers such as glassine, with a density of 1 or more, show a small difference between dispersion ratios of 0.7 and 0.55, ensuring stable conductivity.

[0167] [Table 4]

[0168] [Table 5]

[0169] [Table 6]

[0170] [Table 7]

[0171] [Table 8]

[0172] [Table 9]

[0173] [Table 10]

[0174] [Table 11]

[0175] [Table 12]

[0176] Examples 1 to 10 in Tables 4 to 10 show that low-resistance electronic components can be manufactured by manufacturing electronic components using the manufacturing method of electronic components according to this embodiment.

[0177] From Comparative Examples 1-3 and 7 in Tables 4-10, it can be seen that when a combination of dispersion medium and substrate that does not satisfy Formula I is used, it is not possible to manufacture electronic components with low resistance.

[0178] Examples of embodiments of this model are as follows:

[0179] <1> A printing pattern formation step involves ejecting ink containing copper and a dispersion medium onto a substrate using an inkjet head to form a printed pattern, A drying film formation step involves drying the printed pattern to form a dried film, A method for manufacturing an electronic component, comprising a sintering step of sintering the dried film, The aforementioned substrate is a permeable substrate through which the dispersion medium penetrates, The substrate has heat resistance to the sintering process, The content of the dispersion medium is 40% by mass or more relative to the total amount of the ink. A method for manufacturing an electronic component, characterized in that when Sw is the mass ratio of the dispersion medium to the total amount of ink, T is the penetration and drying time of the dispersion medium into the substrate (seconds), and θ is the contact angle of the dispersion medium with respect to the substrate (°), the following equation I is satisfied.

[0180]

number

[0181] <2> The aforementioned substrate is a cellulosic substrate, <1> This is a method for manufacturing the electronic components described in [the document].

[0182] <3> The aforementioned substrate has a density of 0.5 g / cm³. 3 More than 1.5g / cm 3 The following paper, above <1> or <2> A method for manufacturing electronic components as described above.

[0183] <4> The substrate is glassine paper, <1> from <3> This is a method for manufacturing electronic components as described in any of the following.

[0184] <5> The printing pattern formation step involves heating the substrate while ejecting the ink with the inkjet head. <1> from <4> This is a method for manufacturing electronic components as described in any of the following.

[0185] <6> the above <1> from <5> This chipless RFID is characterized by comprising an electronic component manufactured by the electronic component manufacturing method described in any of the above.

[0186] the above <1> from <5> A method for manufacturing electronic components, and the above <6> This chipless RFID technology can solve the problems of the past and achieve the objectives of this disclosure. [Explanation of Symbols]

[0187] 1 Base 20 ink 21 Copper particles 22 Dry membrane 23 Electronic Components 3 Heaters 4. Inkjet head 5. Hot press machine 6 Printed matter [Prior art documents] [Patent Documents]

[0188] [Patent Document 1] Special Publication No. 2019-529587 [Non-patent literature]

[0189] [Non-Patent Document 1] Lousada CM, Fernandes RMF, Tarakina NV, Soroka IL. Synthesis of copper hydride (CuH) from CuCO3 Cu(OH)2 a path to electrically conductive thin films of Cu. Dalton Trans. 2017 May 23;46(20):6533-6543. doi: 10.1039 / c7dt00511c. PMID: 28379275.

Claims

1. A printing pattern formation step involves ejecting ink containing copper and a dispersion medium onto a substrate using an inkjet head to form a printed pattern, A drying film formation step involves drying the printed pattern to form a dried film, A method for manufacturing an electronic component, comprising a sintering step of sintering the dried film, The aforementioned substrate is a permeable substrate through which the dispersion medium penetrates, The substrate has heat resistance to the sintering process, The content of the dispersion medium is 40% by mass or more relative to the total amount of the ink. When Sw is the mass ratio of the dispersion medium to the total amount of the ink, T is the penetration and drying time of the dispersion medium to the substrate (seconds), and θ is the contact angle of the dispersion medium to the substrate (°), the following formula I is satisfied, characterized in that Manufacturing methods for electronic components. [Math 1]

2. The method for manufacturing an electronic component according to claim 1, wherein the substrate is a cellulose-based substrate.

3. The aforementioned substrate has a density of 0.5 g / cm³. ３ 1.5g / cm or more ３ The method for manufacturing an electronic component according to claim 1, which is as follows:

4. The method for manufacturing an electronic component according to claim 2, wherein the substrate is glassine paper.

5. The method for manufacturing an electronic component according to claim 1, wherein the printing pattern forming step involves heating the substrate while ejecting the ink with the inkjet head.

6. A chipless RFID characterized by comprising an electronic component manufactured by the method for manufacturing an electronic component described in any one of claims 1 to 5.

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