JP2022033596A - Article manufacturing method - Google Patents

Abstract

To provide an article manufacturing method in which the conductivity of a sintered body layer, the adhesion of the sintered body layer to a base material, and the insulation reliability between wiring are satisfied at a high level in an article provided with the base material and the sintered body layer formed on the surface thereof.SOLUTION: An article manufacturing method includes the steps of selectively roughening a part of the surface of a base material to obtain a processed base material having a roughened portion that has been roughened and a non-roughened portion that has not been roughened, forming a metal particle-containing layer using a composition containing metal particles so as to cover at least a part of the roughened portion in the processed base material, and sintering the metal particles in the metal particle-containing layer to form a sintered body layer.SELECTED DRAWING: None

Description

The present invention relates to a method for manufacturing an article.

As a method for forming a circuit pattern, a method called a printed electronics method is known (see, for example, Patent Documents 1 and 2). This method consists of a step of forming a pattern consisting of ink containing metal particles, a paste, etc. on a substrate by inkjet printing, screen printing, dispense printing, etc., and a circuit having conductivity by heating the pattern containing metal particles. Includes a step of forming a pattern. Conductivity is exhibited by the metal particles contained in the ink or paste being sintered by heat to form a sintered body layer.

In recent years, from the viewpoint of reducing the size and weight of wiring, Molded Connect Devices (hereinafter, may be referred to as "MID") has been attracting attention. MID is a member in which wiring is directly formed on a molded body having a three-dimensionally shaped surface such as an uneven surface or a curved surface. For example, electronic components are mounted on the wiring by using solder in various fields. It is used in. According to the MID forming technology, a structure in which wiring is formed in the dead space of the device, a structure in which the harness is removed, and the like can be manufactured, so that it is possible to reduce the weight of the in-vehicle member and the size of the smartphone. As one aspect of the MID forming technique, the Laser Direct Structuring method (hereinafter, may be referred to as “LDS method”) is known. The LDS method includes a step of manufacturing a molded body containing metal particles, a step of irradiating a region on the surface of the molded body to form a circuit with a laser to make the metal particles into a conductor, and a step of making the surface of the molded body into a conductor. It includes a step of forming a circuit by performing electroless plating on the formed portion.

Japanese Unexamined Patent Publication No. 2012-072418 Japanese Unexamined Patent Publication No. 2014-148732

In the printed electronics method, there is a trade-off relationship between the adhesion of the sintered body layer constituting the circuit pattern to the substrate and the conductivity of the sintered body layer. That is, when the binder resin for improving the adhesion of the sintered body layer is blended with the metal particles in the ink or the paste, the conductivity of the sintered body layer tends to decrease. The conventional printed electronics method has room for improvement in this respect.

By the way, according to the study by the present inventors, the sintered body layer formed on the roughened portion obtained by subjecting the surface of the base material to the roughened portion is made of the base material. It was found that the physical engagement with the roughened portion was increased and the adhesion was improved.

On the other hand, further studies by the present inventors have found the following problems. FIG. 4A is a cross-sectional view schematically showing a sintered body layer in a processed substrate in which the roughening treatment is applied to the entire surface of the substrate, and FIG. 4B is a cross-sectional view based on the roughening treatment. It is sectional drawing which shows typically the sintered body layer in the processed base material applied to a part of the material surface. That is, when the entire surface of the base material is roughened, the portion that does not form the sintered body layer also becomes the roughened portion 2a. The roughened portion 2a exhibits high adhesion to the sintered body layer, but tends to wet and spread due to the capillary phenomenon. Therefore, when forming the metal particle-containing layer which is the precursor of the sintered body layer, for example, when the composition containing the metal particles is applied to form the sintered portion 3, the sintered portion 3 is wet and spreads to other than the desired portion. For example, as shown in 3a of FIG. 4A, there may be a problem that the line width becomes thick and it becomes difficult to form fine wiring, and the insulation reliability between the wirings after sintering is lowered (. See FIGS. 4 (a) and 4 (b)).

Further, when the composition containing the metal particles coated in a reducing formic acid atmosphere is fired, the metal-containing component which is a reaction product of the metal particles and formic acid may be sublimated and diffused to other than the coated portion. At this time, if the portion other than the desired portion is roughened, the sublimated component tends to adhere to the base material, which may cause a problem that the insulation reliability between the wirings is lowered after sintering.

The present invention has been made in view of such circumstances, and in an article including a base material and a sintered body layer formed on the surface thereof, the conductivity of the sintered body layer and firing on the base material are obtained. It is an object of the present invention to provide a method for manufacturing an article which satisfies a high level of adhesion of a body layer and insulation reliability between wirings.

One aspect of the present invention relates to a method of manufacturing an article. The method for producing the article has a roughened portion in which a part of the surface of the base material is selectively roughened and has been roughened, and a non-roughened portion in which the roughened portion has not been applied. In the step of obtaining the processed base material, the step of forming the metal particle-containing layer using the composition containing the metal particles so as to cover at least a part of the roughened portion in the processed base material, and the step of forming the metal particle-containing layer. It includes a step of sintering metal particles to form a sintered body layer.

According to the method for manufacturing such an article, the adhesion of the sintered body layer to the substrate and the conductivity of the sintered body layer can be improved. Further, according to the method for producing such an article, a composition containing metal particles is selected so as to selectively roughen a part of the surface of the base material and cover at least a part of the roughened part. Since it is used, it is possible to suppress the wet spread of the composition and the adhesion spread due to the sublimation of the metal-containing component at the time of firing. Therefore, it is possible to prevent a decrease in insulation reliability between wirings.

According to the present invention, in an article including a base material and a sintered body layer formed on the surface thereof, the conductivity of the sintered body layer, the adhesion of the sintered body layer to the base material, and the space between wirings. A method for manufacturing an article that meets a high level of insulation reliability is provided.

FIG. 1 is a perspective view showing an article obtained by the method for producing an article according to an embodiment. 2 (a), 2 (b), and 2 (c) are cross-sectional views schematically showing a process of a method for manufacturing an article according to an embodiment. 3 (a) and 3 (b) are cross-sectional views schematically showing a process of a method for manufacturing an article according to an embodiment. FIG. 4A is a cross-sectional view schematically showing a sintered body layer in a processed substrate in which the roughening treatment is applied to the entire surface of the substrate, and FIG. 4B is a cross-sectional view based on the roughening treatment. It is sectional drawing which shows typically the sintered body layer in the processed base material applied to a part of the material surface.

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to the numerical values and their ranges, and does not limit the present invention.

In the present specification, the term "process" refers to a process that is independent of other processes, and even if the process cannot be clearly distinguished from other processes, if the purpose of the process is achieved, the process is also included. included. In the present specification, the numerical range indicated by using "-" includes the numerical values before and after "-" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. good. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. In the present specification, the content or content of each component in the composition refers to the plurality of types present in the composition when a plurality of substances corresponding to the respective components are present in the composition, unless otherwise specified. Means the total content or content of the substances in.

<Articles and their manufacturing methods>
FIG. 1 is a perspective view showing an article obtained by the method for producing an article according to an embodiment. 2 (a), 2 (b), and 2 (c) are cross-sectional views schematically showing a process of a method for manufacturing an article according to an embodiment. 3 (a) and 3 (b) are cross-sectional views schematically showing a process of a method for manufacturing an article according to an embodiment. As shown in FIG. 1, the article 1 includes a processed base material 2A and a sintered body layer 3 provided on the processed base material 2A. In the processed base material 2A, a part of the surface of the base material 2 is selectively roughened, and the roughened portion 2a that has been roughened and the non-roughened portion 2a that has not been roughened. It has a roughened portion 2b (see FIG. 2C). The sintered body layer 3 is formed in the processed base material 2A so as to cover at least a part of the roughened portion 2a (see FIG. 3B).

The shape of the base material 2 is appropriately selected depending on the intended use and the like. The base material 2 may be, for example, a three-dimensional object having a three-dimensional shape such as an uneven shape. The base material 2 is produced, for example, by molding a resin using a mold. The resin constituting the base material 2 may be a resin having low heat resistance (for example, a resin having a glass transition temperature and / or a 5% thermogravimetric reduction temperature described later), and may be, for example, a thermoplastic resin. .. The thermoplastic resin may be a polyolefin such as polyethylene, polypropylene or polymethylpentene, polycarbonate, acrylonitrile butadiene styrene resin, polystyrene, polyphenylene sulfide, polyethylene terephthalate, polyethylene naphthalate, liquid crystal plastic or the like. The thermoplastic resin may be a mixture of two or more kinds thereof or a copolymer containing a molecular structure thereof. The resin constituting the base material is preferably at least one selected from the group consisting of polypropylene, polycarbonate, acrylonitrile butadiene styrene resin, polystyrene, polyphenylene sulfide, polyethylene terephthalate, polyethylene naphthalate, and liquid crystal plastic.

The glass transition temperature of the resin may be 150 ° C. or lower, 120 ° C. or lower, or 80 ° C. or lower, and may be 30 ° C. or higher. The glass transition temperature of the resin is measured by dynamic viscoelasticity measurement, specifically, for example, using a dynamic viscoelasticity measuring device, a frequency of 10 Hz, a heating rate of 5 ° C./min, and a temperature range of 20 to 260 ° C. Under the condition, tan δ is measured as the temperature showing the maximum value.

The 5% thermogravimetric reduction temperature of the resin may be 400 ° C. or lower, 300 ° C. or lower, 250 ° C. or lower, or 200 ° C. or lower. The 5% thermal weight reduction temperature of the resin is determined by using a thermogravimetric analyzer (TGA) to increase the weight of the resin from 25 ° C. to a temperature rise rate of 5 ° C./min under a nitrogen atmosphere. It is defined as the temperature when the temperature is reduced by 5% by weight with respect to the weight of the resin (before the temperature rise) at 25 ° C.

The base material 2 may contain components other than the resin. The base material 2 may contain, for example, a filler from the viewpoint of improving heat resistance or strength. Examples of the filler include glass, silica, metal oxides, carbon, minerals and the like.

The base material 2 may include, for example, an electrode or wiring composed of gold, silver, copper, nickel, palladium, aluminum, or the like. The electrodes or wiring may be arranged, for example, on the surface or inside of the substrate 2.

The sintered body layer 3 is formed so as to cover at least a part of the roughened portion 2a on one side 2f side (upper surface side in FIG. 1) of the processed base material 2A (base material 2), for example. That is, the sintered body layer 3 may be formed so as to cover a part or all of the roughened portion 2a. When the sintered body layer 3 is formed so as to cover the entire roughened portion 2a, a part of the sintered body layer 3 may be formed on the non-roughened portion 2b (FIG. 3 (b)). reference).

One surface 2f of the processed base material 2A (base material 2) may be a surface having a three-dimensional shape such as an uneven surface or a curved surface. The sintered body layer 3 is a layer having conductivity, and may be, for example, wiring forming an electric circuit (may be linear when viewed from above).

The sintered body layer 3 may be a layer containing a copper sintered body. The sintered body layer 3 may be obtained by sintering a composition containing copper particles (details will be described later). The sintered body layer 3 may be, for example, a porous layer. The porosity of the sintered body layer 3 may be 10% or more, 13% or more, or 15% or more, and may be 70% or less, 55% or less, or 40% or less. The porosity of the sintered body layer 3 is obtained by analyzing a cross-sectional image of the sintered body layer 3 observed with a scanning electron microscope, a scanning ion microscope, or the like using image analysis software. It means the ratio of the area of the non-conductive portion where the sintered body does not exist to the total area of the three cross sections.

The sintered body layer 3 can be a fine wire-like wiring having a sufficient thickness. The thickness of the sintered body layer 3 may be 1.0 μm or more, 5.0 μm or more, 7.0 μm or more, or 10.0 μm or more, and may be 200 μm or less, 100 μm or less, 60 μm or less, 50 μm or less, or 32 μm or less. There may be. The line width of the sintered body layer 3 (the length in the lateral direction (direction perpendicular to the direction in which the wiring extends) of the sintered body layer 3 (wiring) when viewed from above) is 5 mm or less, 3 mm or less, and 1 mm or less. , 0.7 mm or less, 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, or 0.2 mm or less.

Subsequently, a method for manufacturing the article 1 will be described with reference to FIGS. 2 (a), 2 (b), and 2 (c). In the manufacturing method, a part of the surface of the base material 2 is selectively roughened, and the roughened portion 2a that has been roughened and the non-roughened portion 2b that has not been roughened are formed. A metal particle-containing layer 3p using a composition containing metal particles so as to cover at least a part of the roughened portion 2a in the step of obtaining the processed substrate 2A to have (first step) and the processed substrate 2A. (Second step) and a step (third step) of sintering metal particles to form a sintered body layer 3 are provided. Here, the metal particles may contain a sintered metal, for example, silver (Ag), copper (Cu), palladium (Pd), aluminum (Al), nickel (Ni), zinc (Zn), tin ( Sn), bismuth (Bi), indium (In), iron (Fe) and the like may be contained. The sinterable metal is a metal that can form a sintered body when the metal particles are heated at a temperature lower than the melting point. Hereinafter, the case where the sinterable metal is copper will be described in detail as an example, but in the following description, "copper" may be replaced with "another metal having sinterability".

(First step)
This step is a step of preparing the base material 2 and selectively roughening a part of the surface of the base material 2. Here, the surface of the base material means the surface on which the metal particle-containing layer 3p and the sintered body layer 3 are formed (the surface on which the metal particle-containing layer 3p and the sintered body layer 3 are planned to be formed), and the metal particle-containing layer. The surface on which 3p and the sintered layer 3 are not arranged is not included. 2A and 2B are diagrams showing a step of roughening a part of the surface of the base material 2 on the one side 2f side, and roughen a part of the surface of the base material 2 on the one side 2f side. It is a step of processing (see FIGS. 2A and 2B), and FIG. 2B is a diagram showing a roughening process by a laser 5 as an example of the roughening process. By these roughening treatments, a processed base material 2A having a roughened portion 2a that has been roughened and a non-roughened portion 2b that has not been roughened can be obtained (see FIG. 2C). .. By using such a processed base material 2A, the adhesion of the sintered body layer to the base material can be improved.

Examples of the roughening treatment include laser irradiation treatment, polishing treatment, sandblasting treatment, wet blasting treatment, frame treatment, corona treatment, plasma treatment and the like. Further, the roughening treatment may be, for example, a molding treatment using a mold having an uneven surface. The roughening treatment can be arbitrarily selected according to the desired characteristics. The roughening treatment may be at least one selected from the group consisting of a laser irradiation treatment, a polishing treatment, a sandblasting treatment, and a wet blasting treatment, and since fine and selective roughening can be easily performed, a laser is used. Irradiation treatment is more preferable.

In the laser irradiation treatment, fine and selective roughening can be easily performed by selectively irradiating a desired portion of the substrate. In addition, the spot diameter of the laser can be adjusted in micrometer units. Therefore, by using a laser, for example, roughening treatment can be performed with a line width of 100 μm or less. Further, even when one surface 2f of the base material 2 has a three-dimensional shape, it is possible to selectively perform the roughening treatment.

As the laser irradiation device, for example, a laser marker used for processing resin or ceramics can be used. As the laser, for example, a CO2 laser (wavelength: 10.6 μm), a near infrared laser (wavelength: 1064 nm), a visible light laser (wavelength: 532 nm), an ultraviolet laser (wavelength: 355 nm) and the like can be used.

Examples of the laser irradiation parameters include laser average output (W), frequency (Hz), scan speed (mm / s), and the like. These parameters can be appropriately set according to the shape (line or surface) of the sintered body layer 3 to be formed, the material of the base material 2, and the like. For example, when the base material 2 is irradiated with a laser under predetermined conditions and the laser is coarsened wider than the portion to be roughened, the laser output is lowered, the Q-switch frequency is increased, the scan speed is increased, and the like. You just have to take measures. According to the study by the present inventors, the scan speed is higher when the sintered body layer 3 is formed in a planar shape, that is, in the case where the roughened portion is formed in a planar shape, as compared with the case where the roughened portion is formed in a linear shape. It is preferable to increase the value. Further, when treating a base material having low thermal conductivity, it is preferable to increase the scan speed because the heat generated by laser irradiation is less likely to diffuse and is easily roughened as compared with the base material having high thermal conductivity.

The laser irradiation may be carried out while blowing a reducing gas on the region to be irradiated with the laser, or may be carried out in an air atmosphere without blowing such a gas. When the metal electrode is already formed on the resin base material, it is preferably carried out under an inert atmosphere (for example, nitrogen, argon, etc.) or a reducing atmosphere in order to suppress the oxidation of the metal electrode.

In wet blasting, sandblasting and the like, the portion sprayed with the abrasive can be selectively roughened. When performing fine processing, for example, a protective layer (masking) is arranged on the base material 2 to be a non-roughened portion 2b by attaching a tape, exposure development of a resist film, or the like, and the entire base material 2 is covered with a protective layer (masking). A method such as roughening is effective.

Polishing can be performed by rubbing the surface of the base material with, for example, polishing paper or the like. Further, for polishing, a fine roughening treatment having a width of about 1 mm can be performed by using a hand grinder or the like having a shape like a needle having an elongated tip.

For example, in the base material 2, the roughening treatment was performed by arranging a protective layer (masking) on the portion to be the non-roughened portion 2b and performing the roughening treatment on the portion where the protective layer was not arranged. A processed base material 2A having a roughened portion 2a and a non-roughened portion 2b that has not been roughened can be efficiently obtained.

The roughening treatment may be carried out so that the surface roughness Ra (arithmetic mean roughness (JIS B 0601-2001)) of the roughened portion 2a of the processed substrate 2A is in the range of 0.05 to 10.0 μm. preferable. The surface roughness of the roughened portion 2a of the processed base material 2A is more preferably 0.1 to 6.0 μm from the viewpoint of good adhesion strength and the cross-sectional shape of the wiring.

(Second step)
This step is a step of forming a metal particle-containing layer 3p using a composition containing copper particles so as to cover at least a part of the roughened portion 2a in the processed base material 2A (FIG. 3A). reference). The metal particle-containing layer 3p is formed on the surface of the processed base material 2A on the one side 2f side.

The metal particle-containing layer 3p can be formed, for example, by a method using an aerosol jet. As the device, a spraying device including an atomizer and a discharge nozzle connected to the atomizer can be used. As such a spraying device, a device to which a known spraying method is applied can be used as it is. Known injection methods include, for example, an aerosol deposition method, a cold spray method, a thermal spray method and the like.

The metal particle-containing layer 3p can also be formed by a method using a jet dispenser. As the device, a syringe, a discharge nozzle connected to the syringe, and a coating device provided with a movable portion for discharging the metal particle composition from the nozzle can be used. As such a coating device, a device to which a known coating method is applied can be used as it is.

The metal particle-containing layer 3p is formed in the processed base material 2A so as to cover at least a part of the roughened portion 2a. That is, the metal particle-containing layer 3p may be formed so as to cover a part or all of the roughened portion 2a. When the metal particle-containing layer 3p is formed so as to cover the entire roughened portion 2a, a part of the metal particle-containing layer 3p may be formed on the non-roughened portion 2b (FIG. 3A). reference).

When the metal particle-containing layer 3p is formed by the above method, it is preferable to adjust the roughened portion 2a of the processed base material 2A so as to cover the entire surface, and then spray or apply the composition. As such a method, for example, a protective layer (masking) is arranged on the portion to be the non-roughened portion 2b, and the composition is sprayed or applied to the roughened portion 2a.

The composition used in this step (composition for forming a metal sintered body layer) contains at least copper particles, and further contains, for example, a dispersion medium. Copper particles contain copper as a main component from the viewpoint of thermal conductivity and sinterability. The ratio of the copper element in the copper particles may be 80 atomic% or more, 90 atomic% or more, or 95 atomic% or more based on all the elements except hydrogen, carbon, and oxygen. When the element ratio is 80 atomic% or more, the thermal conductivity and sinterability derived from copper tend to be easily exhibited.

The shape of the copper particles is not particularly limited, and examples thereof include a spherical shape, a substantially spherical shape, a polyhedral shape, a needle shape, a flake shape, and a rod shape. The copper particles include at least flake-shaped copper particles, and may further contain other copper particles having different shapes. By including copper particles having different shapes, cracking of the formed wiring is suppressed, and it tends to be easy to form a wiring having a sufficient thickness. The reason for this is not necessarily clear, but it is considered that the copper particles having different shapes complement each other in the gaps and suppress the omnidirectional generation of volume reduction due to the fusion of the copper particles to each other. As a result, it is presumed that cracks are suppressed even in wiring having a sufficient thickness. The combination of those having different shapes is not particularly limited, but for example, a combination of flake-shaped copper particles (A1) and spherical copper particles (A2) is preferable.

The median diameter of the flake-shaped copper particles (A1) is 1.0 μm or more. The lower the heat resistance of the resin base material, the greater the influence of expansion, contraction, and warpage due to temperature changes in the firing process, and the wiring is more likely to crack. The larger the median diameter of the flake-shaped copper particles, the more the cracks can be suppressed. From this point of view, the median diameter may be 5.0 μm or more or 8.0 μm or more. The upper limit of the median diameter can be 20.0 μm from the viewpoint of easily maintaining good low-temperature sinterability and coatability. The median diameter of the spherical copper particles (A2) may be 0.1 to 2.0 μm, 0.1 to 1.2 μm, 0.1 to 0.9 μm, or 0.1 to 0.6 μm. By combining the flake-shaped copper particles (A1) having such a median diameter and the spherical copper particles (A2), the fusion property at a low temperature tends to be more excellent. The median diameter of the particles means the value of D50 (cumulative median value of volume distribution) measured by a laser folding particle size distribution meter (for example, Submicron Particle Analyzer N5 PLUS (Beckman Coulter), etc.).

The ratio of the content of the spherical copper particles (A2) to the content of the flake-shaped copper particles (A1) in the composition (content of the spherical copper particles (A2) / content of the flake-shaped copper particles (A1)) is , 0.25 to 4.0, 0.3 to 3.0, or 0.4 to 2.5. When the content of the spherical copper particles (A2) is in such a range with respect to the content of the flake-shaped copper particles (A1), cracking tends to be more suppressed.

The content of the copper particles may be 20 to 90 parts by mass with respect to 100 parts by mass of the total mass of the composition. The content of the copper particles may be 30 parts by mass or more, 40 parts by mass or more, or 50 parts by mass or more. When the content of the copper particles is 20 parts by mass or more with respect to 100 parts by mass of the total mass of the composition, there is a tendency that wiring having a sufficient thickness can be formed. The content of the copper particles may be 85 parts by mass or less, 80 parts by mass or less, 75 parts by mass or less, 70 parts by mass or less, or 65 parts by mass or less. When the content of the copper particles is 85 parts by mass or less with respect to 100 parts by mass of the total mass of the composition, the ejection property from the apparatus tends to be more excellent.

In one embodiment, the copper particles may be copper-containing particles having core particles containing copper and an organic substance covering at least a part of the surface of the core particles. The copper-containing particles may include, for example, copper-containing core particles and an organic substance containing a substance derived from an alkylamine present on at least a part of the surface of the core particles. The alkylamine may be an alkylamine having 7 or less carbon atoms in the hydrocarbon group. Since the copper-containing particles have a relatively short chain length of the hydrocarbon group of the alkylamine constituting the organic substance, they are thermally decomposed even at a relatively low temperature (for example, 150 ° C. or lower), and the core particles are easily fused to each other. As such copper-containing particles, for example, the copper-containing particles described in JP-A-2016-037627 can be preferably used. From the viewpoint of achieving excellent conductivity, it is preferable that no organic matter remains in the sintered body layer 3, and the content of the organic matter in the sintered body layer 3 is preferably 3% by mass or less. It is preferably 1% by mass or less. According to the manufacturing method according to the present embodiment, even if the sintered body layer 3 does not contain a binder resin (organic substance), excellent adhesion of the sintered body layer 3 to the base material 2 can be achieved.

The organic substance may contain an alkylamine having 7 or less carbon atoms in the hydrocarbon group. The alkylamine having 7 or less carbon atoms in the hydrocarbon group may be, for example, a primary amine, a secondary amine, an alkylenediamine or the like. Examples of the primary amine include ethylamine, 2-ethoxyethylamine, propylamine, 3-ethoxypropylamine, butylamine, 4-methoxybutylamine, isobutylamine, pentylamine, isopentylamine, hexylamine, cyclohexylamine, heptylamine and the like. be able to. Examples of the secondary amine include diethylamine, dipropylamine, dibutylamine, ethylpropylamine, ethylpentylamine and the like. Examples of the alkylenediamine include ethylenediamine, N, N-dimethylethylenediamine, N, N'-dimethylethylenediamine, N, N-diethylethylenediamine, N, N'-diethylethylenediamine, 1,3-propanediamine, and 2,2-dimethyl-. 1,3-Propane diamine, N, N-dimethyl-1,3-diaminopropane, N, N'-dimethyl-1,3-diaminopropane, N, N-diethyl-1,3-diaminopropane, 1,4 -Diaminobutane, 1,5-diamino-2-methylpentane, 1,6-diaminohexane, N, N'-dimethyl-1,6-diaminohexane, 1,7-diaminoheptane and the like can be mentioned. ..

The organic substance that covers at least a part of the surface of the core particles may contain an organic substance other than the alkylamine having 7 or less carbon atoms in the hydrocarbon group. The ratio of the alkylamine having 7 or less carbon atoms in the hydrocarbon group to the whole organic substance is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more. preferable.

The proportion of the organic matter covering at least a part of the surface of the core particles is preferably 0.1 to 20% by mass with respect to the total of the core particles and the organic matter. When the proportion of organic matter is 0.1% by mass or more, sufficient oxidation resistance tends to be obtained. When the proportion of organic matter is 20% by mass or less, it tends to be easy to achieve conductor formation at a low temperature. The ratio of the organic matter to the total of the core particles and the organic matter is more preferably 0.3 to 10% by mass, further preferably 0.5 to 5% by mass.

The copper-containing particles contain at least copper and may contain other substances as needed. Examples of other substances include metals such as gold, silver, platinum, tin and nickel, compounds containing these metal elements, reducing compounds or organic substances, oxides, chlorides and the like. From the viewpoint of forming a conductor having excellent conductivity, the content of copper in the copper-containing particles is preferably 50% by mass or more, more preferably 60% by mass or more, and more preferably 70% by mass or more. Is even more preferable. The method for producing the copper-containing particles is not particularly limited. Examples of the production method include a method for producing copper-containing particles disclosed in Japanese Patent Application Laid-Open No. 2016-0376226.

The dispersion medium is not particularly limited and may be appropriately selected from organic solvents generally used for producing conductive inks, conductive pastes and the like, depending on the intended use. As the dispersion medium, one type may be used alone or two or more types may be used in combination. From the viewpoint of viscosity adjustment, the dispersion medium is terpineol, isobornylcyclohexanol, dihydroterpineol, dihydroterpineol acetate, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, ethylene glycol, propylene glycol, Diethylene glycol, dipropylene glycol, glycerin, tributyrin, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, propyl acetate, butyl acetate, ethyl lactate and the like may be used. The content of the dispersion medium may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, and 300 parts by mass or less, 200 parts by mass or less, or 150 parts by mass with respect to 100 parts by mass of the copper particles. It may be as follows.

The composition may further contain other components other than the copper particles and the dispersion medium, if necessary. Examples of other components include a silane coupling agent, a polymer compound (resin), a radical initiator, a reducing agent, a rheology adjuster, and the like. In addition, examples of other components include other metal particles other than copper particles. Examples of other metal particles include particles such as aluminum, nickel, tin, bismuth, indium, zinc, iron, silver, gold, palladium, and platinum. The content of the other metal particles may be less than 20% by mass and may be 10% by mass or less based on the total mass of the metal particles contained in the composition from the viewpoint of obtaining sufficient bondability. .. When other metal particles are included, the content of the dispersion medium set based on the content of the copper particles can be set based on the content of the copper particles and the metal particles.

The viscosity of the composition at 25 ° C. can be appropriately set depending on the method of use of the composition, for example, 10 to 100,000 mPa · s, 100 to 80,000 mPa · s, 500 to 60,000 mPa · s, or 1000 to 40,000 mPa · s. May be. The viscosity of the composition at 25 ° C. is measured at 25 ° C. using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: VISCOMETER-TV22, applicable cone plate type rotor: 3 ° × R17.65). Means viscosity.

The method for producing the composition is not particularly limited, and a method usually used in the art can be used. For example, it can be prepared by dispersing copper particles and a dispersion medium, and if necessary, other components. Dispersion processing includes media dispersers such as Ishikawa stirrer, rotating and revolving stirrer, ultra-thin high-speed rotary disperser, roll mill, ultrasonic disperser, bead mill, and cavitation stirrer such as homomixer and Silberson stirrer. An opposed collision method such as an ultimateizer can be used. Moreover, you may use these methods in combination as appropriate.

(Third step)
This step is a step of sintering the metal particles in the metal particle-containing layer 3p to form the sintered body layer 3 (see FIG. 3B). Here, by heating the metal particle-containing layer 3p, the organic matter is thermally decomposed and the metal particles are fused to each other to form the sintered body layer 3. The sintered body layer 3 can be said to be a conductor layer (that is, a conductor layer). Thereby, the article 1 can be obtained. The heating temperature for sintering may be, for example, 250 ° C. or lower, 230 ° C. or lower, 210 ° C. or lower, 100 ° C. or higher, 110 ° C. or higher, or 120 ° C. or higher. In the case of sintering at such a low temperature, even if the heat resistance of the base material 2 and the processed base material 2A is not sufficient, the sintered body layer is not damaged by the base material 2 and the processed base material 2A. 3 can be formed. The heating temperature for sintering is usually 100 ° C. or higher. In particular, when copper-containing particles having a core particle containing copper and an organic substance covering at least a part of the surface of the core particle are used, the conductor can be formed at a low temperature, so that the heating temperature for forming the conductor layer is obtained. May be 200 ° C. or lower, or 180 ° C. or lower.

The heating temperature for sintering may be constant, or may be changed regularly or irregularly. The heating time is not particularly limited and can be selected in consideration of the heating temperature, the heating atmosphere, the amount of copper-containing particles, and the like. The heating method is not particularly limited, and may be, for example, heating by a hot plate, an infrared heater, or a pulse laser.

The atmosphere in which the metal particle-containing layer 3p is heated is not particularly limited, but may be an inert atmosphere containing nitrogen, argon, or the like, or a reducing atmosphere containing a reducing substance such as hydrogen or formic acid. The pressure is not particularly limited, but heating the metal particle-containing layer 3p in a reduced pressure atmosphere tends to promote conductor formation at a lower temperature.

In terms of low-temperature firing, a reducing atmosphere containing formic acid is particularly preferable.

The method for producing an article having a sintered body layer (conductor layer) may further include other steps, if necessary. Other steps include, for example, a step of removing at least a part of volatile components in the metal particle-containing layer 3p before heating for sintering the metal particles of the metal particle-containing layer 3p, a step of removing the metal particle-containing layer 3p. After sintering the metal particles of the above, the formed sintered body layer (conductor layer) is further heated in a reducing atmosphere to reduce the oxide (copper oxide) contained in the sintered body layer (conductor layer). Steps, a step of removing residual components in the sintered body layer (conductor layer) by light firing of the sintered body layer (conductor layer), a step of applying a load to the sintered body layer (conductor layer), etc. Can be mentioned.

Article 1 can be suitably used as an MID (sometimes also referred to as a molding circuit component, a three-dimensional molding circuit component, a three-dimensional molding circuit component, or the like). Specifically, the article 1 is suitably used as a smartphone antenna, in-vehicle wiring, a laminated board, a solar cell panel, a display, a transistor, a semiconductor package, a laminated ceramic capacitor and the like. The article 1 can also be used as a member such as an electric wiring, a heat radiating film, and a surface covering film.

Although the embodiment of the present invention has been described, the present invention is not limited to the above embodiment. For example, in the above embodiment, the case where copper particles that are easily oxidized are used as metal particles, although they have the advantage of low material cost, has been exemplified. However, instead of copper particles, silver particles, silver-copper particles, and silver are exemplified. -Palladium particles, tin particles, tin bismuth particles, aluminum particles or nickel particles may be used.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to the following examples.

<Preparation of composition>
70 parts by mass of the copper particles (A) shown below and 30 parts by mass of the organic solvent (B) shown below were mixed to prepare a composition for forming a metal sintered body layer. The median diameter (D50) of the copper particles was measured using a submicron particle analyzer N5 PLUS (Beckman Coulter).

(Copper particles (A))
As the copper particles (A), flake-shaped copper particles (A1) and spherical copper particles (A2) are mixed at a ratio of 30:70 (mass ratio) (spherical copper particles (spherical copper particles) with respect to the content of the flake-shaped copper particles (A1). The ratio of the content of A2) (content of spherical copper particles (A2) / content of flake-shaped copper particles (A1): 2.3) was used.
Flake-shaped copper particles (A1): Product name: 3L3N, Fukuda Metal Foil Powder Industry Co., Ltd., Mediane diameter (D50): 5.0 μm
Spherical copper particles (A2): Product name: CH0200, Mitsui Mining & Smelting Co., Ltd., Mediane diameter (D50): 0.15 μm

(Organic solvent (B))
As the organic solvent, a mixture of 70 parts by mass of terpineol and 30 parts by mass of tributyrin was used.

[Example 1]
<Preparation of processed base material>
A polypropylene (PP) substrate (size: 30 mm × 30 mm) was prepared, and the PP substrate was roughened. Specifically, 2 mm wide tape is masked on the substrate at 2 mm intervals, and the surface of the unmasked substrate is rubbed with water-resistant abrasive paper (manufactured by Sankyo Rikagaku Co., Ltd., particle size # 120) to roughen the surface. And a processed substrate having a non-roughened portion was obtained. The surface roughness Ra of the roughened portion of the processed substrate was 4.7 μm.

<Formation of metal particle-containing layer>
In the obtained processed substrate as it was masked, the above composition was applied using a squeegee so as to cover the roughened portion. The composition was adjusted so that the composition remained on the processed substrate by the thickness of the tape. Subsequently, the tape was peeled off, and the processed substrate coated with the composition was dried at a temperature of 90 ° C. for 5 minutes to form a metal particle-containing layer.

<Formation of sintered layer>
Subsequently, the processed substrate provided with the metal particle-containing layer was heated in a nitrogen atmosphere containing 3% formic acid under the condition that the temperature was raised to 110 ° C. at a heating rate of 6 ° C./min and held at 110 ° C. for 60 minutes. As a result, the article of Example 1 was obtained.

[Comparative Example 1-1]
The article of Comparative Example 1-1 was obtained in the same manner as in Example 1 except that a PP substrate (size: 30 mm × 30 mm) that had not been roughened was used.

[Comparative Example 1-2]
The article of Comparative Example 1-2 was obtained in the same manner as in Example 1 except that a PP substrate (size: 30 mm × 30 mm) which had been roughened on the entire surface without masking was used.

[Example 2]
<Preparation of processed base material>
A PP substrate (size: 30 mm × 30 mm) was prepared and roughened with abrasive paper in a linear shape with a line width of 1 mm at 1 mm intervals to obtain a processed substrate having a roughened portion and a non-roughened portion.

<Formation of metal particle-containing layer>
In the obtained processed substrate, the above composition was applied linearly with a line width of 1 mm using a jet dispenser so as to cover the roughened portion, and a metal particle-containing layer was formed.

<Formation of sintered layer>
A sintered layer was formed in the same manner as in Example 1 to obtain the article of Example 2.

[Comparative Example 2]
The article of Comparative Example 2 was obtained in the same manner as in Example 2 except that a PP substrate (size: 30 mm × 30 mm) which had been roughened on the entire surface using abrasive paper was used.

[Example 3]
<Preparation of processed base material>
A polypropylene (PP) case (size: 70 mm × 100 mm × 30 mm) was prepared. The surface of the PP case is roughened in the same manner as in Example 2, and a processed base material having an L-shaped roughened portion and other non-roughened portions on two adjacent surfaces is provided. Obtained.

<Formation of metal particle-containing layer>
In the obtained processed substrate, the above composition was applied linearly with a line width of 1 mm using a jet dispenser so as to cover the roughened portion, and a metal particle-containing layer was formed. In the PP case, the coating was continuously applied to two adjacent surfaces to form an L-shaped metal particle-containing layer.

<Formation of sintered layer>
A sintered layer was formed in the same manner as in Example 1 to obtain the article of Example 3.

[Comparative Example 3-1]
The article of Comparative Example 3-1 was obtained in the same manner as in Example 1 except that a PP case (size: 70 mm × 100 mm × 30 mm) which had not been roughened was used.

[Comparative Example 3-2]
The article of Comparative Example 3-2 was obtained in the same manner as in Example 3 except that a PP case (size: 70 mm × 100 mm × 30 mm) which had been roughened using abrasive paper was used. ..

[Example 4]
<Preparation of processed base material>
A PP case (size: 70 mm × 100 mm × 30 mm) was prepared. The surface of the PP case is roughened in a linear line with a line width of 1 mm at 1 mm intervals by laser irradiation treatment, and an L-shaped roughened portion and other non-roughened portions are applied to two adjacent surfaces. A processed substrate having the above was obtained. A fiber laser processing machine (GunyucutGT1300R, manufactured by Gunkyo Seisakusho Co., Ltd.) was used as a laser irradiation device, and laser irradiation was performed under the following conditions.
-Laser: Near infrared laser (wavelength: 1.07 μm)
・ Laser average output: 18W
・ Frequency: 500Hz
・ Scan speed: 500-4000 mm / s
・ Laser irradiation atmosphere: Atmosphere

<Formation of metal particle-containing layer>
In the obtained processed substrate, the above composition was applied linearly with a line width of 1 mm using a jet dispenser so as to cover the roughened portion, and a metal particle-containing layer was formed. In the PP case, the coating was continuously applied to two adjacent surfaces to form an L-shaped metal particle-containing layer.

<Formation of sintered layer>
A sintered layer was formed in the same manner as in Example 1 to obtain the article of Example 4.

[Comparative Example 4]
The article of Comparative Example 4 was obtained in the same manner as in Example 4 except that a PP case (size: 70 mm × 100 mm × 30 mm) which had been subjected to the same roughening treatment by laser irradiation treatment on the entire surface was used.

[Example 5]
<Preparation of processed base material>
A polyphenylene sulfide (PPS) substrate (size: 30 mm × 30 mm) was prepared. The surface of the PPS substrate was roughened in the same manner as in Example 4 to obtain a processed substrate having a roughened portion and a non-roughened portion.

<Formation of metal particle-containing layer>
In the obtained processed substrate, the above composition was applied linearly with a line width of 1 mm using a jet dispenser so as to cover the roughened portion, and a metal particle-containing layer was formed.

<Formation of sintered layer>
A sintered layer was formed in the same manner as in Example 1 to obtain the article of Example 4.

[Comparative Example 5]
The article of Comparative Example 5 was obtained in the same manner as in Example 5 except that the PPS substrate (size: 30 mm × 30 mm) subjected to the roughening treatment by the same laser irradiation treatment was used on the entire surface.

<Various evaluations>
(Conductivity of sintered body layer)
The volume resistivity of the formed sintered body layer was measured by the surface resistance value measured by a four-ended needle surface resistance measuring instrument and by a non-contact surface / layer cross-sectional shape measuring system (VertScan, manufactured by Mitsubishi Chemical Systems, Inc.). It was calculated from the thickness of the sintered body layer. The conductivity of the sintered body layer was evaluated according to the following criteria based on the value of volume resistivity. Generally, if the volume resistivity is less than 100 μΩ · cm, it can be said that the conductivity is excellent. The results are shown in Table 1, Table 2, Table 3, Table 4, and Table 5.
A: It was less than 10 μΩ · cm.
B: It was 10 μΩ · cm or more and less than 30 μΩ · cm.
C: It was 30 μΩ · cm or more and less than 100 μΩ · cm.
D: It was 100 μΩ · cm or more.

(Adhesion of the sintered body layer to the substrate)
The formed sintered body layer was visually observed, a scratch test with tweezers, and a tape peeling test were carried out to evaluate the adhesion. Adhesion was judged according to the following criteria. When the following criteria A or B are satisfied, it can be said that the adhesion is good. The results are shown in Table 1, Table 2, Table 3, Table 4, and Table 5.
A: There was no peeling after the tape peeling test.
B: There was no peeling after the scratch test with tweezers.
C: No peeling was visually observed, but there was peeling after the scratch test with tweezers.
D: Peeling was visually observed.

(Insulation reliability between wiring)
After applying the solder resist from above the wiring, the resist was cured by heating in a nitrogen atmosphere at 120 ° C. for 1 hour. Regarding the insulation reliability between the wiring, the initial value of the insulation resistance and the value after the migration test (leaved for 100 hours under the conditions of temperature 85 ° C, humidity 85%, 20V application) were measured for 6 samples, and out of all 6 samples. , The ratio of samples having an insulation resistance value of ¹⁰⁹ Ω or more was calculated. From the obtained ratio, the insulation reliability was determined according to the following criteria. It can be said that the insulation reliability is good when the following criteria A or B are satisfied. The results are shown in Table 1, Table 2, Table 3, Table 4, and Table 5.
A: The ratio of insulation resistance value of 109 Ω or more was ⁶ out of 6 samples.
B: The ratio of insulation resistance value of 109 Ω or more was ⁵ out of 6 samples.
C: The ratio of insulation resistance value of 109 Ω or more was ⁴ samples or 3 samples out of all 6 samples.
D: The ratio of the insulation resistance value of 109 Ω or more was ² samples, 1 sample, or 0 sample out of all 6 samples.

As shown in Table 1, Table 2, Table 3, Table 4, and Table 5, a processed substrate having a roughened portion that has been roughened and a non-roughened portion that has not been roughened is used. The article of the example was excellent in conductivity, adhesion, and insulation reliability. On the other hand, the article of the comparative example using the base material not subjected to the roughening treatment was insufficient in terms of conductivity, adhesion, and insulation reliability. Further, the article of the comparative example using the processed base material on which the roughening treatment was applied to the entire surface was excellent in terms of conductivity and adhesion, but was insufficient in terms of insulation reliability. From these results, the article manufactured by the method for manufacturing an article of the present invention satisfies the conductivity of the sintered body layer, the adhesion of the sintered body layer to the substrate, and the insulation reliability between wirings at a high level. It was confirmed that.

1 ... Article, 2 ... Base material, 2A ... Processed base material, 2a ... Roughened part, 2b ... Non-roughened part, 3 ... Sintered body layer, 3p ... Metal particle-containing layer, 5 ... Laser.

Claims (5)

A part of the surface of the base material is selectively roughened to obtain a processed base material having the roughened portion subjected to the roughening treatment and the non-roughened portion not subjected to the roughening treatment. Process and
A step of forming a metal particle-containing layer using a composition containing metal particles so as to cover at least a part of the roughened portion in the processed substrate.
A step of sintering the metal particles in the metal particle-containing layer to form a sintered body layer,
A method of manufacturing an article. The method for producing an article according to claim 1, wherein the roughening treatment is at least one selected from the group consisting of a laser irradiation treatment, a polishing treatment, a sandblasting treatment, and a wet blasting treatment. The method for producing an article according to claim 1 or 2, wherein the metal particles are copper particles. The method for producing an article according to any one of claims 1 to 3, wherein the base material is made of a resin. The method for producing an article according to claim 4, wherein the resin is at least one selected from the group consisting of polypropylene, polycarbonate, acrylonitrile butadiene styrene resin, polystyrene, polyphenylene sulfide, polyethylene terephthalate, polyethylene naphthalate, and liquid crystal plastic. ..

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