JP6738077B1 - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress elution due to heat and pressure of a joining means for conductively joining an electronic element to a metal wiring pattern formed on a deformable base material, to hold the electronic element on the metal wiring pattern with high positional accuracy, and to electrically perform it. An electronic device that can maintain bonding is provided. A deformable base material, a metal wiring pattern arranged on the base material, an electronic element bonded to the metal wiring pattern by a bonding means containing a heat-meltable conductive component, and a metal wiring of the base material A resin layer covering one surface on which the pattern is arranged, and a resin coating layer having a higher softening point than the resin layer and covering part or all of the joining means so as to be separated from the resin layer are provided. [Selection diagram] Figure 2

Description

The present invention relates to electronic devices.

An electronic circuit for performing a predetermined process, a base on which the electronic circuit is arranged, one end of which is bent and bonded to a pad provided on the base and electrically connected to the electronic circuit via the pad , The other end becomes a connector terminal and is used for positioning during secondary molding, and the electronic circuit, substrate and one end of the pin header are resin-sealed so that the connector terminal is exposed. A module including the above-mentioned primary mold body is known (Patent Document 1).

A method for manufacturing an electromechanical structure, the method comprising: forming a plurality of conductors and/or a plurality of graphic bodies on a substantially flat film, the method comprising: A step of mounting a plurality of electronic elements on the film, a step of forming a film accommodating the electronic elements into a substantially three-dimensional shape, and a step of substantially forming an insert in an injection molding process by substantially molding on the film. Using a different three-dimensional film, a preferred layer of material is attached to the surface of the film to create an electromechanical structure (US Pat.

Japanese Patent Application No. 2017-207318 Japanese Patent Publication No. 2016-539034

The present invention suppresses melt-out due to heat and pressure of a joining means for conductively joining an electronic element to a metal wiring pattern formed on a deformable substrate, holds the electronic element on the metal wiring pattern with high positional accuracy, and Provided is an electronic device capable of maintaining a mechanical bond.

In order to solve the problem, the electronic device according to claim 1,
A thermoformable substrate,
A metal wiring pattern arranged on the substrate,
An electronic element joined by a joining means containing a heat-meltable conductive component to the metal wiring pattern including an external connection terminal for electrically connecting to an external element,
A resin layer that covers at least one surface of the base material on which the metal wiring pattern is arranged so that the terminal surface, which is the surface of the external connection terminal, is exposed .
A resin coating layer having a higher softening point than the resin layer and covering part or all of the joining means so as to be separated from the resin layer;
It is characterized by

The invention described in claim 2 is the electronic device according to claim 1, wherein
The metal wiring pattern is a metal plating layer made of Cu formed on a conductive layer made of metal nanoparticles.
It is characterized by

The invention described in claim 3 is the electronic device according to claim 1 or 2 , wherein:
The joining means is a low temperature solder having a melting temperature lower than the softening point of the base material,
It is characterized by

According to a fourth aspect of the present invention, in the electronic device according to any one of the first to third aspects,
The resin layer is made of a thermoplastic material, and the resin coating layer is made of a thermosetting resin material, a two-component curable resin material, a photocurable resin material, or a moisture curable resin material,
It is characterized by

The invention described in claim 5 is the electronic device according to any one of claims 1 to 4 ,
The surface of the base material opposite to the surface on which the metal wiring pattern is arranged is covered with a thermoplastic resin layer,
It is characterized by

According to the first aspect of the present invention, the electronic element is electrically connected to the metal wiring pattern formed on the deformable base material as compared with the configuration in which the resin coating layer that covers a part or the whole of the joining means is not provided. It is possible to suppress melting of the joining means to be joined due to heat and pressure , reduce stress acting on the electronic element, and suppress damage to the external connection terminal .

According to the second aspect of the invention, the metal wiring pattern can be arranged along the three-dimensional shape of the deformed base material.

According to the invention described in claim 3, it can be conductively joined the electronic element to the metal wiring pattern disposed on NetsuNaru type capable substrates.

According to the fourth aspect of the invention, it is possible to suppress the softening of the resin coating layer when the resin layer contacts the resin coating layer.

According to the invention described in claim 5 , the strength of the electronic device can be improved.

FIG. 3 is a schematic plan view showing an example of the electronic device according to the present embodiment without showing a resin layer. FIG. 3 is a schematic partial cross-sectional view showing an example of the electronic device according to the present embodiment. It is a partial cross section schematic diagram which shows an example of the other aspect of the electronic device which concerns on this embodiment. It is a flowchart figure which shows an example of the outline procedure of the manufacturing method of the electronic device which concerns on this embodiment. It is a plane schematic diagram which shows the electronic device which concerns on an Example, without showing a resin layer. (A) is a schematic partial plan view showing the joining of the metal wiring pattern and the pin header in the embodiment, (b) is a schematic partial sectional view showing the joining of the metal wiring pattern and the pin header, (c) is a metal filled with a resin layer It is a partial cross-sectional schematic diagram which shows the joining state of a wiring pattern and a pin header. It is a figure which shows the lighting confirmation result of LED in the electronic device which concerns on an Example.

Next, specific examples of embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.
In the following description using the drawings, it should be noted that the drawings are schematic and the ratios of the respective dimensions and the like are different from the actual ones. Illustrations other than the members are appropriately omitted.

(1) Overall Configuration of Electronic Device FIG. 1 is a schematic plan view showing an example of the electronic device according to the present embodiment without showing a resin layer, and FIG. 2 is a partial sectional schematic diagram showing the example of the electronic device according to the present embodiment. FIG. 3 is a partial cross-sectional schematic view showing an example of another aspect of the electronic device according to the present embodiment.
Hereinafter, the configuration of the electronic device according to the present embodiment will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the electronic device 1 includes an insulating base material 2 made of a thermoplastic resin and a wiring pattern formed by applying a conductive ink containing metal nanoparticles on the base material 2. A metal wiring pattern 3 formed by plating on the formed conductive layer 3a, and a pin header 5 as an example of an electronic element joined to the metal wiring pattern 3 by a low temperature solder 4 as an example of joining means, A resin coating layer 6 that covers a part or all of the low-temperature solder 4 and a resin layer 7 that covers the one surface 2a of the base material 2 on which the metal wiring pattern 3 is arranged are provided.

(Base material)
The insulating base material 2 used in this embodiment is not limited to a film-shaped base material, but will be described below as a film-shaped base material.
The material of the substrate 2 is an insulating deformable thermoplastic resin, and when the melting point Tm exists, it is preferably 150° C. or higher, more preferably 200° C. or higher.
The range of the glass transition point Tg of the substrate 2 is preferably 20°C to 250°C, more preferably 50°C to 200°C, most preferably 70°C to 150°C. If the glass transition point Tg is too low, the strain of the base material 2 may increase during the sintering of the metal nanoparticles.

The material of the base material 2 is not particularly limited as long as it satisfies the conditions of the melting point Tm and the glass transition point Tg as described above, and specifically, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) ( PE), polyamides (PA) such as nylon 6-10 and nylon 46, polyether ether ketone (PEEK), thermoplastic resins such as ABS, PMMA and polyvinyl chloride.
In particular, polyester (PE) is more preferable, and among them, polyethylene terephthalate (PET) is the most preferable because it has a good balance of economical efficiency, electric insulation, chemical resistance and the like.

The thickness of the base material 2 is preferably 5 μm to 3 mm, more preferably 12 μm to 1 mm, and most preferably 50 μm to 200 μm. If the thickness of the base material 2 is too thin, the strength will be insufficient and the distortion of the base material 2 may increase during the plating process of the metal wiring pattern 3. The thickness is a condition when the substrate 2 is a film-shaped substrate, and the insulating substrate 2 to which the present invention is applied is not limited to the film-shaped substrate.

The surface of the base material 2 is preferably surface-treated in order to uniformly apply the conductive ink containing the metal nanoparticles. As the surface treatment, for example, corona treatment, plasma treatment, solvent treatment, primer treatment can be used.

The film-shaped base material 2 made of such a deformable thermoplastic resin can be transformed from a substantially flat two-dimensional shape to a substantially flat two-dimensional shape by thermoforming, vacuum forming, or pressure forming depending on the required usage of the electronic device 1. Is formed into a three-dimensional shape.

(Metal wiring pattern)
When disposing the metal wiring pattern 3 on the surface of the base material 2, the conductive layer 3a composed of metal nanoparticles is applied first.
The thickness of the conductive layer 3a is preferably 100 nm to 20 μm, more preferably 200 nm to 5 μm, and most preferably 500 nm to 2 μm. If the conductive layer 3a is too thin, the strength of the conductive layer 3a may decrease. Further, if the conductive layer 3a is too thick, the metal nanoparticles are more expensive than ordinary metal, and therefore the manufacturing cost may increase.

As the material of the metal nanoparticles, gold (Au), silver (Ag), copper (Cu), palladium (Pd), nickel (Ni) and the like are used, and gold (Au), silver (Ag) are used from the viewpoint of conductivity. ) And copper (Cu) are preferable, and silver that is less likely to be oxidized than copper (Cu) and cheaper than gold (Au) is most preferable.

The particle size of the metal nanoparticles is preferably 1 nm to 500 nm, more preferably 10 nm to 100 nm. If the particle size is too small, voids for introducing the resin of the base material 2 by heating and pressurization become difficult to occur, and the reactivity of the particles becomes high, which may adversely affect the storage stability and stability of the ink. is there. If the particle size is too large, it may be difficult to form a thin film uniformly, and ink particles may easily precipitate.

The metal wiring pattern 3 is formed on the conductive layer 3a by electrolytic plating or electroless plating. As the plating metal, copper (Cu), nickel (Ni), silver (Ag), gold (Au), or the like can be used, but copper (Cu) is preferably used in terms of extensibility, conductivity, and price. Most preferred.

The thickness of the plating layer is preferably 0.03 μm to 100 μm, more preferably 1 μm to 35 μm, most preferably 3 μm to 18 μm. If the plating layer is too thin, the mechanical strength may be insufficient and the conductivity may not be sufficiently obtained in practical use. If the plating layer is too thick, the time required for plating may be long and the manufacturing cost may increase.

A plurality of electronic components are attached to the metal wiring pattern 3. The electronic components include control circuits, distortion, resistance, electrostatic capacitance, touch sensing such as TIR, and light detection components, tactile components or vibration components such as piezoelectric actuators or vibration motors, light emitting components such as LEDs, microphones and speakers. Sounding or receiving sounds such as, memory chip, programmable logic chip and device operating parts such as CPU, digital signal processor (DSP), ALS device, PS device, processing device, MEMS and the like. FIG. 1 shows a heater 3A, which is a resistor, an LED 3B, which is a light emitting component, and a touch sensor 3C, as an example of these electronic components.

(Electronic element)
A pin header 5 as an example of an electronic element is bonded onto the metal wiring pattern 3. The pin header 5 is an external connection terminal for electrically connecting a plurality of electronic components mounted on the electronic device 1 electrically connected to the metal wiring pattern 3 and an external element provided outside the electronic device 1. 51 and a pin holding portion 52 that holds a plurality of external connection terminals 51 so that they are separated from each other by a predetermined distance.

The external connection terminal 51 is formed in a square pole shape using, for example, a copper alloy. It should be noted that the external connection terminal 51 may be, for example, nickel-plated on the surface and plated with a metal such as gold (AU) or tin (Sn) or an alloy containing these metals on the nickel plating. good. The pitch of the external connection terminals 51 depends on the standard of the connector to be connected. The external connection terminal 51 includes, for example, a terminal portion 51 a that serves as a connector terminal and an anchor portion 51 b that is joined to the metal wiring pattern 3, and the anchor portion 51 b is joined to the metal wiring pattern 3.

(Low temperature solder)
The anchor portion 51b of the external connection terminal 51 of the pin header 5 is joined to the metal wiring pattern 3 with a low temperature solder 4 as an example of joining means containing a heat-meltable conductive component. The low-temperature solder 4 is a solder having a melting temperature lower than the softening point of the base material 2, and includes, for example, an alloy (SnBi) of tin (Sn) and bismuth (Bi), tin (Sn) and bismuth (Bi). Alloy (SnBiNiCu) of nickel (Ni) and copper (Cu), alloy (SnBiCuSb) of tin (Sn), bismuth (Bi), copper (Cu) and antimony (Sb), tin (Sn) and silver (Ag). ) And bismuth (Bi) alloy (SnAgBi), tin (Sn) and indium (In) alloy (SnIn), tin (Sn), indium (In) and bismuth (Bi) alloy (SnInBi), Alternatively, another combination of another alloy having a melting point relatively lower than the softening point of the base material 2 and bismuth (Bi) and/or indium (In) can be used. It is desirable to have a melting point of 120 to 140° C. lower than the softening point of polyethylene terephthalate (PET).

Specifically, as the solder paste of the low temperature solder 4, a solder paste represented by Sn-40Bi-(0 to 1.1)Cu-0.03Ni can be mentioned. Examples of such low-temperature solder 4 include a trade name "ECO SOLDER PASTE LT142" (manufactured by Senju Metal Industry Co., Ltd.).

By using a solder paste having a melting point lower than the softening point of the base material 2, the reflow process can be controlled so that the reflow temperature is higher than the melting point of the solder paste but lower than the softening point of the base material 2. .. Specifically, for example, when the base material 2 is polyethylene terephthalate (PET), by performing the reflow process at 140° C., the base material 2 does not melt or otherwise deform, but the solder paste melts. As a result, the metal wiring pattern 3 can be chemically and physically joined. Then, the low temperature solder 4 is solidified, and the pin header 5 as an example of an electronic element is bonded to the metal wiring pattern 3 via the low temperature solder 4.

(Resin layer)
The resin layer 7 is formed by performing secondary molding on the one surface 2a of the base material 2 on which the metal wiring pattern 3 and the pin header 5 are arranged, and the main body portion 71 that covers the one surface 2a on which the metal wiring pattern 3 is arranged. And a connector portion 72 having a cylindrical shape and exposing the external connection terminal 51 of the pin header 5 inside the cylinder.

The resin layer 7 is a thermoplastic resin made of a thermoplastic resin material that can be secondarily molded. Specifically, polycarbonate (PC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polyamide (PA), acrylic butadiene styrene (ABS), polyethylene (PE), polypropylene (PP), modified polyphenylene ether (m -PPE), modified polyphenylene oxide (m-PPO), cycloolefin copolymer (COC), cycloolefin polymer (COP), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), or a mixture thereof. A plastic resin can be used.

As shown in FIG. 3B, the resin layer 7 may be formed on the surface 2b of the base material 2 opposite to the one surface 2a on which the metal wiring pattern 3 is arranged. The strength of the electronic device 1 can be improved by forming the resin layer 7 on the surface 2 b opposite to the one surface 2 a of the base material 2.

(Resin coating layer)
The resin coating layer 6 covers a part or all of the low temperature solder 4 that joins the pin header 5 as an example of an electronic element onto the metal wiring pattern 3, and the resin layer 7 is molded on one surface of the base material 2 by injection molding or the like. In doing so, the molten resin of the low-temperature solder 4 is prevented from being melted by coming into contact with the high-temperature molten resin and being melted by heat and pressure.
Therefore, the resin coating layer 6 is a material having a higher softening point than the material of the resin layer 7, and is made of a thermosetting resin material, a two-component curable resin material, a photocurable resin material, or a moisture curable resin material. It is a curable resin. Specifically, for example, various resins such as epoxy resin, urethane resin, acrylic resin, polyimide resin, polyamide resin, bismaleimide resin, phenol resin, polyester resin, silicone resin, oxetane resin can be used. You may use these individually or in combination of 2 or more types. Of these, epoxy resin is particularly preferable.

These curable resin materials are also used as adhesives and paints, have high adhesion to various materials, and have a low viscosity in the state of a monomer before curing, so that they are excellent in moldability and have excellent pinability. This is suitable for covering the entire low temperature solder 4 that joins the anchor portion 51b to the metal wiring pattern 3.

These curable resins have excellent heat resistance, chemical resistance, and dimensional stability after curing, and when the resin layer 7 is secondarily molded by injection molding, the temperature of the molten resin is, for example, 280°C to 320°C. When the temperature is set to 0° C., it is possible to suppress softening of the resin coating layer 6 that comes into contact with the molten resin forming the resin layer 7, and to prevent the molten resin of the low-temperature solder 4 from being melted by heat and pressure. As a result, the pin header 5 can be held on the metal wiring pattern 3 with high positional accuracy and electrical connection can be maintained.
In addition, these curable resins may contain an inorganic filler such as a glass filler or a mineral filler, and these curable resins may be used alone or in combination of two or more kinds. Good.

As shown schematically in FIG. 3A, the resin coating layer 6 is formed by filling a portion of or all of the low-temperature solder 4 as a joining means and the pin header 5 as an example of an electronic element by injection molding. The resin layer 7 may be disposed so as to be thermally separated from the resin layer 7 and not affected by the pressure.

(2) Method of Manufacturing Electronic Device FIG. 4 is a flowchart showing an example of a schematic procedure of a method of manufacturing the electronic device 1 according to the present embodiment.
The electronic device 1 is a conductive ink applying step S1 of applying a conductive ink containing metal nanoparticles (metal nanoparticle ink) onto a deformable substrate 2 made of a thermoplastic resin by an inkjet method or flexographic printing. And a plating step S2 for forming a metal wiring pattern on the conductive ink layer by plating, and a solder paste application for applying a solder paste for joining the pin header 5 as an example of an electronic element on the metal wiring pattern 3. Step S3, a joining step S4 in which the pin header 5 is placed on the metal wiring pattern 3 and joined in a reflow process, and a coating step S5 for covering a part or all of the low temperature solder 4 solidified in the reflow process with a thermosetting resin. And a resin filling step S6 in which a thermoplastic resin is secondarily molded by injection molding so as to cover one surface of the base material 2 to which the pin header 5 is bonded on the metal wiring pattern 3.

(Conductive ink application process)
As a method of applying the metal nanoparticle ink to the base film, an inkjet method and flexographic printing can be mentioned. In this embodiment, the inkjet method is used. Specifically, a low viscosity metal nanoparticle ink of 1000 cps or less, for example, 2 cps to 30 cps is applied by an inkjet method, and then the solvent is volatilized to leave only the metal nanoparticles. Then, the solvent is removed (drying) and the silver nanoparticles are sintered (baking).

The content ratio of the metal nanoparticles in the ink is preferably 5% to 60% by mass, and more preferably 10% to 30%. If the content ratio is too low, there is a possibility that pinholes may occur due to insufficient nanoparticles required to form the conductive layer of metal nanoparticles, and if the content ratio is too high, particles tend to aggregate in the ink. For example, stability may be impaired.

(Plating process)
The metal nanoparticle layer formed on the base material 2 through the metal nanoparticle ink coating step is subjected to electrolytic plating or electroless plating to deposit a plating metal on the surface and inside of the metal nanoparticle layer. The plating method is the same as a known plating solution and plating treatment, and specific examples thereof include electroless copper plating and electrolytic copper plating.

(Solder paste application process)
In order to bond the pin header 5 onto the metal wiring pattern 3 formed on the base material 2, a solder paste of the low temperature solder 4 is applied to form the low temperature solder 4. Printing of the solder paste can be performed using a known device such as a stencil printing device, a screen printing device, and a dispenser device. In this embodiment, the solder paste is applied using a dispenser device.

(Joining process)
After the solder paste is applied on the metal wiring pattern 3 by the dispenser device, the pin header 5 is mounted by using, for example, a device mounting device or the like, the solder is melted and solidified, and the low temperature solder 4 is applied on the metal wiring pattern 3. The anchor portion 51b of the pin header 5 is joined. For example, the base material 2 made of a thermoplastic resin that can be deformed by thermoforming or the like has a low softening point, but by performing the reflow process at 140° C. using the low temperature solder 4, the base material 2 can be used in the joining process. It does not melt or otherwise deform due to heat.

(Coating process)
The coating step S5 is a step of forming a resin coating layer 6 that covers part or all of the low temperature solder 4 and the pin header 5 by applying a curable resin. The resin coating layer 6 formed in the coating step S5 separates the low temperature solder 4 from the heat and pressure of the molten resin of the resin layer 7 to be secondarily molded.

(Resin filling process)
In the resin filling step S6, the laminated body of the base material 2, the metal wiring pattern 3, the pin header 5, the low temperature solder 4 and the resin coating layer 6 formed up to the coating step S5 was placed on the secondary molding die. The rear mold is closed and the thermoplastic resin is injection-molded so as to cover one surface of the base material 2.
The low temperature solder 4 that joins the metal wiring pattern 3 and the pin header 5 is subjected to a reflow process at 140° C., for example, but the resin coating layer 6 made of a curable resin having a softening point higher than that of the resin layer 7 is used for thermal and pressure In the resin filling step S6, the normal thermoplastic resin can be injection-molded with the resin temperature set at 280° C. to 320° C.
In the resin introducing step S6, the thermoplastic resin is injected by injection molding while the mold and the pin header 5 are positioned to form the resin layer 7.

"Example"
FIG. 5 is a schematic plan view showing the electronic device 1 according to the embodiment without showing the resin layer 7, and FIG. 6A is a partial schematic plan view showing the joining of the metal wiring pattern 3 and the pin header 5 in the embodiment, ( FIG. 7B is a partial cross-sectional schematic view showing the joining of the metal wiring pattern 3 and the pin header 5, and FIG. 7C is a partial cross-sectional schematic diagram showing the joining state of the metal wiring pattern 3 and the pin header 5 filled with the resin layer 7. It is a figure which shows the lighting confirmation result of LED3B in the electronic device 1 which concerns on an Example.
Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
In this example, the electronic device 1 was prepared and the lighting of the LED 3B was confirmed as follows.

(Base material)
A PET film having a thickness of 125 μm was cut into a predetermined size to obtain a base material 2.

(Circuit formation)
The conductive layer 3a of the metal nanoparticle ink was formed on the PET film by an inkjet device, and the metal wiring pattern 3 was formed by copper (Cu) by electroless plating.
Further, as shown in FIG. 5, part of the metal wiring pattern 3 was formed as a heater 3A and a touch sensor 3C. Further, a plurality of LEDs 3B are mounted on the metal wiring pattern 3 as an example of a light emitting component.

(Electronic element)
On the metal wiring pattern 3, a pin header 5 for electrically connecting to an external element provided outside the electronic device 1 was joined by soldering. Solder is a low-temperature solder, product name "ECO SOLDER PASTE LT142" (made by Senju Metal Industry Co., Ltd.), high-temperature solder, product name "ECO SOLDER PASTE M705-GRN360-K2-V" (made by Senju Metal Industry Co., Ltd.), low temperature Bonding was carried out by a reflow process controlled at 140° C. using a trade name “ECO SOLDER PASTE L20-JPP” (manufactured by Senju Metal Industry Co., Ltd.) made of solder and epoxy resin.

(Resin coating layer)
As shown in FIGS. 6( a) and 6 (b ), the resin coating layer 6 is a moisture-curable resin adhesive such as “Super X” (Cemedine), a moisture-curable silicone rubber adhesive. A part of the solder and the pin header 5 was coated with the product name "KE348" (manufactured by Shin-Etsu Chemical Co., Ltd.).

(Resin layer)
As shown in FIG. 6C, the laminated body of the base material 2, the metal wiring pattern 3, the pin header 5, the low temperature solder 4 and the resin coating layer 6 is placed on the secondary molding die and the resin layer 7 is placed. As an example, injection molding was performed using polycarbonate (PC), trade name “UPILON S-2000” (manufactured by Mitsubishi Engineering Plastics Co., Ltd.). By this injection molding, a connector shape was formed so as to surround the pin header 5.

(Example 1)
Solder: "ECO SOLDER PASTE LT142"
Resin coating layer: "Super X"
In the electronic device 1 according to the first embodiment, as a result of external power supply via the pin header 5, as shown in FIG. 7, it was confirmed that the LED 3B was turned on at all 10 times.

(Example 2)
Solder: "ECO SOLDER PASTE LT142"
Resin coating layer: "KE348"
In the electronic device 1 according to the second embodiment, as shown in FIG. 7, the lighting of the LED 3B was confirmed at all five times.

(Comparative Example 1)
Solder: "ECO SOLDER PASTE LT142"
Resin coating layer: None In the electronic device 1 according to Comparative Example 1, the LED 3B was turned on only once in 10 times, and the LED 3B was not turned on 9 times.

(Comparative example 2)
Solder: "ECO SOLDER PASTE M705-GRN360-K2-V"
Resin coating layer: None In the electronic device 1 according to the comparative example 2, the lighting of the LED 3B was confirmed only twice in 10 times, but it was unstable. Further, the lighting of the LED 3B was not confirmed 8 times.

(Comparative example 3)
Solder: "ECO SOLDER PASTE L20-JPP"
Resin coating layer: None In the electronic device 1 according to Comparative Example 3, the LED 3B was turned on three times out of ten times, and was unstable once. Further, the lighting of the LED 3B was not confirmed 6 times.

As described above, in Examples 1 and 2 in which the resin layer 7 was secondarily molded with the metal wiring pattern 3 and part of the pin header 5 covered with the resin coating layer 6, the low temperature solder 4 (“ECO SOLDER PASTE LT 142") is covered with the resin coating layer 6 having a softening point higher than that of the resin layer 7, so that it is presumed that the molten resin of the low-temperature solder 4 is prevented from being melted by heat and pressure. It As a result, the pin header 5 is held on the metal wiring pattern 3 with high positional accuracy and electrical connection is maintained.

According to the electronic device 1 of the present embodiment, before the low temperature solder 4 for joining the pin header 5 as an example of the electronic element on the metal wiring pattern 3 is injection-molded with the resin layer 7 using the thermoplastic resin, By performing secondary molding in a state in which the resin is coated with a curable resin in advance, the deformable base material 2 is provided as compared with a configuration in which the resin coating layer 6 that covers the low temperature solder 4 as an example of the joining means is not provided. It is possible to suppress melting of the low temperature solder 4 for conductively bonding the electronic element to the metal wiring pattern 3 formed thereon due to heat and pressure.
Further, the low temperature solder 4 for conductively joining the electronic element to the metal wiring pattern 3 formed on the deformable base material 2 is prevented from being melted by heat and pressure, and the electronic element is held on the metal wiring pattern 3 with high accuracy. The electrical connection can be maintained.

DESCRIPTION OF SYMBOLS 1... Electronic device 2... Base material 3... Metal wiring pattern 4... Low temperature solder 5... Pin header 6... Resin coating layer 7... Resin layer

Claims (5)

A thermoformable substrate,
A metal wiring pattern arranged on the substrate,
An electronic element joined by a joining means containing a heat-meltable conductive component to the metal wiring pattern including an external connection terminal for electrically connecting to an external element,
A resin layer that covers at least one surface of the base material on which the metal wiring pattern is arranged so that the terminal surface, which is the surface of the external connection terminal, is exposed.
A resin coating layer having a higher softening point than the resin layer and covering part or all of the joining means so as to be separated from the resin layer,
An electronic device characterized by the above. The metal wiring pattern is a metal plating layer made of Cu formed on a conductive layer made of metal nanoparticles.
The electronic device according to claim 1, wherein: The joining means is a low temperature solder having a melting temperature lower than the softening point of the base material,
Electronic device according to claim 1 or 2, characterized in that. The resin layer is made of a thermoplastic material, and the resin coating layer is made of a thermosetting resin material, a two-component curable resin material, a photocurable resin material, or a moisture curable resin material,
The electronic device according to any one of claims 1 to 3 , wherein: The surface of the base material opposite to the surface on which the metal wiring pattern is arranged is covered with a thermoplastic resin layer,
The electronic device according to any one of claims 1 to 4 , wherein:

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