Method for manufacturing conductive circuit

Abstract

To provide a method for manufacturing a conductive circuit which can reduce electric resistance, while securing insulation.SOLUTION: A method for manufacturing a conductive circuit includes coating a resin paste 73 constituting a first insulation layer 71 contacting a substrate 40 onto a substrate, coating a conductive particle paste 60 in which conductive particles 21 are dispersed in a dispersion liquid onto the resin paste and then heat treating and curing the conductive particle paste in the atmosphere, and forming a recess 30 on a part of the surface of the first insulation layer and forming a porous layer containing conductive particles. Subsequently, an electroless plating solution impregnated into the porous layer is held in the recess of the first insulation layer, the conductive particles dispersed inside the porous layer are connected to each other by plating precipitated metal 22 precipitated from the electroless plating solution, and a conductive body 20 is formed by the porous layer. The resin paste is coated onto the conductor and then is heat-treated and cured in the atmosphere, and a second insulation layer 72 coating the conductor is formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a conductive circuit.

Background Art

[0002] In vehicles such as automobiles, a wire harness composed of a bundle of a plurality of electric wires, terminals, and connectors is used for power supply and signal communication. However, when manufacturing a vehicle, there is a problem that the work of attaching the wire harness to the vehicle requires a large number of man-hours. In addition, the wire harness also has problems such as being thick, heavy, and having little freedom in layout.

[0003] To solve these problems, a technique of replacing a wire harness with a conductive circuit formed by printed electronics technology has been proposed. For example, Patent Document 1 discloses a technique for manufacturing a printed laminated circuit having a printed resin insulating layer made of soluble polyimide and a printed copper wiring formed on the printed resin insulating layer. In the technique of Patent Document 1, a soluble polyimide-containing high heat-resistant coating agent and a copper paste for printing are heat-treated using an inert gas such as nitrogen or a reducing gas and under high-temperature conditions (300°C). Thereby, a soluble polyimide layer and a copper wiring are formed to manufacture a printed laminated circuit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the technology of Patent Document 1 uses an inert gas such as nitrogen or a reducing gas and performs high-temperature heat treatment, the target members on which a printed laminated circuit can be directly formed are limited. Furthermore, even when heat treatment is performed at 300°C, there is a problem that the electrical resistance of the copper wiring is relatively large (6.5 to 8.0 μΩ·cm, see Table 1 of Patent Document 1).

[0006] Therefore, an object of the present invention is to provide a method for manufacturing a conductive circuit that can suppress the electrical resistance while ensuring insulation.

Means for Solving the Problems

[0007] A method for manufacturing a conductive circuit according to an aspect of the present invention for achieving the above object coats a resin paste constituting a first insulating layer in contact with a substrate on the substrate, coats a conductive particle paste in which conductive particles are dispersed in a dispersion liquid on the resin paste, and then heat-treats and cures it in an air atmosphere to form a concave portion in a part of the surface of the first insulating layer and form a porous layer containing the conductive particles. Next, an electroless plating solution to be impregnated into the porous layer is held in the concave portion of the first insulating layer, and the conductive particles dispersed inside the porous layer are connected to each other by the plating-precipitated metal precipitated from the electroless plating solution to form a conductor by the porous layer. Then, after coating the resin paste on the conductor and heat-treating and curing it in an air atmosphere, a second insulating layer covering the conductor is formed.

Effects of the Invention

[0008] In the method for manufacturing a conductive circuit according to one aspect of the present invention, a recess is formed in a part of the surface of the first insulating layer, and a porous layer in a stage before forming a conductor is located in the recess. By holding electroless plating solution in the recess, the electroless plating solution can easily impregnate into the inside of the porous layer. In the porous layer, the bonding rate of connecting conductive particles with each other by plating deposition metal deposited from the electroless plating solution is increased, and the electrical resistance can be lowered. The conductor formed by the porous layer is covered with a second insulating layer. Accordingly, it is possible to provide a method for manufacturing a conductive circuit capable of suppressing the electrical resistance while ensuring insulation.

Brief Description of Drawings

[0009]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The embodiments shown here are examples for embodying the technical idea of the present invention and do not limit the present invention. Therefore, all other possible embodiments, examples, operation techniques, etc. that can be conceived by those skilled in the art without departing from the gist of the present invention are included in the scope and gist of the present invention, and are included in the invention described in the claims and its equivalent scope.

[0011] In addition, the drawings attached to this specification may be changed from the actual objects in scale, aspect ratio of vertical and horizontal dimensions, shape, etc. for the convenience of illustration and easy understanding, but this is only an example and does not limit the interpretation of the present invention.

[0012] In this specification, ordinal numbers such as "first" and "second" may be attached. However, unless there is a special explanation regarding these ordinal numbers, they are attached for the convenience of explanation to identify components and do not specify numbers or order.

[0013] As shown in FIG. 1, in the conductive circuit 10, the periphery of the conductor 20 is surrounded by a resin insulating layer 70 to ensure electrical insulation. The resin insulating layer 70 includes a first insulating layer 71 that is in contact with the substrate 40 and has a recess 30, and a second insulating layer 72 that covers the conductor 20 located in the recess 30. The conductor 20 includes conductive particles 21 and a plating deposited metal 22 that connects the conductive particles 21 to each other.

[0014] The plated deposited metal 22 shown has a particulate shape. Hereinafter, the plated deposited metal 22 having a particulate shape is also referred to as a plated deposited metal particle 22. The conductor 20 has a structure in which a plurality of dispersed conductive particles 21 are connected by the plated deposited metal particles 22. For this reason, the conductor 20 may have voids. The recess 30 is used to hold the electroless plating solution 50 for depositing the plated deposited metal 22 (see FIG. 3C). The conductive circuit 10 is formed on the substrate 40. The conductive circuit 10 of the embodiment can be used, for example, as a conductive circuit for a vehicle.

[0015] The conductive particles 21 are particles having an average particle diameter of, for example, 1 μm or more and 1000 μm or less. The conductive particles 21 are composed of a metal. The plated deposited metal particles 22 are particles having an average particle diameter smaller than that of the conductive particles 21. The plated deposited metal particles 22 are composed of the plated deposited metal 22 deposited by electroless plating. The plurality of conductive particles 21 are arranged in a dispersed state within the conductor 20. The plated deposited metal particles 22 are arranged between the conductive particles 21 and connect the conductive particles 21 to each other. The plated deposited metal particles 22 are in contact with the surface of the conductive particles 21. A part or all of the surface of the conductive particles 21 can be covered by the plated deposited metal particles 22. The surface of the conductor 20 can be covered by a plated metal film. The plated metal film is composed of the plated deposited metal 22 deposited by electroless plating.

[0016] In the conductor 20 constituting the wiring, since the current mainly flows through the conductive particles 21, it is preferable that the average particle diameter of the conductive particles 21 is larger. However, if the average particle diameter of the conductive particles 21 is too large, the connection between the particles becomes almost point contact, and the electrical resistance of the conductor 20 may increase. If the average particle diameter of the conductive particles 21 is within the above numerical range, the electrical resistance (volume resistivity; the same applies hereinafter) of the conductive circuit 10 is likely to be low. For this reason, the conductive circuit 10 can pass a large current and can be suitably used as a conductive circuit for a vehicle.

[0017] The plating-deposited metal 22 that connects the conductive particles 21 to each other does not necessarily have to be a particle. However, when the plating-deposited metal 22 is a particle, it is preferable that the average particle diameter of the plating-deposited metal particles 22 is smaller than the average particle diameter of the conductive particles 21. The conductive particles 21 are more effectively connected to each other via the plating-deposited metal particles 22. Since a plurality of conductive particles 21 dispersed in the conductor 20 are electrically connected by the plating-deposited metal particles 22, the electrical resistance of the conductive circuit 10 is likely to be low. For this reason, the conductive circuit 10 can conduct a large current and can be suitably used as a conductive circuit for a vehicle.

[0018] The metal constituting the conductive particle 21 and the metal constituting the plating-deposited metal particle 22 may be the same kind of metal or different kinds of metals. Also, the types of the metal constituting the conductive particle 21 and the metal constituting the plating-deposited metal particle 22 are not particularly limited, but may be at least one of copper (Cu), nickel (Ni), and silver (Ag). Among these metals, copper is preferable because of its low cost.

[0019] The thickness and width of the conductor 20 are not particularly limited.

[0020] While referring to FIG. 2, FIGS. 3A to 3E, and FIG. 1, the manufacturing procedure of the conductive circuit 10 will be described.

[0021] First, as shown in step S1 of FIG. 2, a resin paste 73 constituting a resin insulating layer 70 is applied onto a substrate 40 (see FIG. 3A).

[0022] The resin paste 73 contains a polyamide resin, polyvinyl chloride (PVC), or an epoxy resin. According to these materials, it becomes easy to form a paste. Also, it can be applied in either a non-contact form in which the tip of the resin paste nozzle 74 is separated from the applied resin paste 73 (see FIG. 4A) or a form in which the tip of the resin paste nozzle 74 is brought into contact with the applied resin paste 73 (see FIG. 4B). The resin paste 73 also contains a solvent.

[0023] The coating method of the resin paste 73 is not particularly limited, and it can be coated using a dispenser device, an inkjet device, or the like. The coating conditions are not particularly limited, and the coating can be performed under normal temperature and pressure environment.

[0024] Next, as shown in step S2 of FIG. 2, a conductive particle paste 60 in which conductive particles 21 are dispersed in a dispersion liquid is coated on the resin paste 73 (see FIG. 3B). Before heat treatment curing, when the conductive particle paste 60 is applied and printed, the resin paste 73 is deformed into a bowl shape (concave shape) by the self-weight of the conductive particle paste.

[0025] The conductive particle paste 60 contains conductive particles 21, a binder, and a liquid medium.

[0026] The type of the binder is not particularly limited as long as it has the property of curing by heat, light, etc. For example, thermosetting resins such as epoxy resins and phenolic resins can be used. Alternatively, those containing a flux component (oleic acid, carboxylic acid, etc.) can also be used.

[0027] The type of the liquid medium is not particularly limited as long as it can disperse the conductive particles 21 and the binder. For example, water and organic solvents can be mentioned. Examples of the organic solvent include ethylene glycol.

[0028] The coating method of the conductive particle paste 60 is not particularly limited, and it can be coated using a dispenser device, an inkjet device, or the like. The coating conditions are not particularly limited, and the coating can be performed under normal temperature and pressure environment.

[0029] Next, as shown in step S3 of FIG. 2, the resin paste 73 and the conductive particle paste 60 are heat-treated and cured to form a concave portion 30 in a part of the surface of the first insulating layer 71 and to form a porous layer 24 containing the conductive particles 21 (see FIG. 3B).

[0030] The method for forming the recess 30 will be described later.

[0031] By heat, the solvent is volatilized from the resin paste 73 and the resin component is cured. Also, by heat, the liquid medium is volatilized from the conductive particle paste 60 and the binder is cured, and the film of the conductive particle paste 60 is denatured into a porous layer 24 having a cured reaction product 23 of the conductive particles 21 and the binder. The method for curing the binder is not particularly limited, but considering that the volatilization of the liquid medium is carried out simultaneously, curing by heat is preferable. The curing temperature varies depending on the type of binder.

[0032] Next, as shown in step S4 of FIG. 2, the electroless plating solution 50 to be impregnated into the porous layer 24 is held in the recess 30 of the first insulating layer 71, and electroless plating is performed (see FIGS. 3C, 3D, and 3E). The electroless plating solution 50 can be applied from above the porous layer 24 placed in the recess 30 of the first insulating layer 71. Since the electroless plating solution 50 accumulates in the recess 30, the electroless plating solution 50 easily penetrates into the porous layer 24 (see FIGS. 3C and 3D). The plating deposited metal 22 (for example, plating deposited metal particles) deposited from the electroless plating solution 50 connects the conductive particles 21 dispersed inside the porous layer 24 to form a conductor 20 by the porous layer 24 (see FIG. 3E).

[0033] Next, as shown in steps S5 and S6 of FIG. 2, after the resin paste 73 is applied onto the conductor 20 and heat-treated and cured, a second insulating layer 72 covering the conductor 20 is formed (see FIG. 1). By applying and printing the resin paste 73 from above the porous layer 24 placed in the recess 30 of the first insulating layer 71, a resin insulating layer 70 (the first insulating layer 71 and the second insulating layer 72) covering the conductor 20 is formed.

[0034] In the manufacturing method of the conductive circuit 10 described above, a recess 30 is formed in a part of the surface of the first insulating layer 71, and the porous layer 24 in the stage before forming the conductor 20 is located in the recess 30. By holding the electroless plating solution 50 in the recess 30, the electroless plating solution 50 can easily penetrate into the porous layer 24. Metal ions in the plating solution are deposited around the conductive particles 21. As a result of the increase in the deposition amount of the plating deposited metal 22, the bonding rate connecting the conductive particles 21 with each other by the plating deposited metal 22 is increased, and the electrical resistance can be lowered. The conductor 20 formed by the porous layer 24 is covered with the second insulating layer 72. Thereby, while ensuring insulation, a conductive circuit 10 with low electrical resistance can be obtained.

[0035] The conductive particles 21 of the conductive particle paste 60 have a particle diameter of, for example, 1 μm or more and 1000 μm or less.

[0036] With such a configuration, a gap can be secured between the conductive particles 21, and the electroless plating solution 50 penetrates into the gap, so that the plating deposited metal 22 is likely to be deposited from the electroless plating solution 50 (see FIGS. 3D and 3E). As a result, the metal contact rate increases, and the electrical resistance can be made lower.

[0037] The conductive particle paste 60 is applied onto the resin paste 73 so that the porous layer 24 does not protrude from the recess 30 of the first insulating layer 71.

[0038] With such a configuration, the electroless plating solution 50 can be reliably held in the recess 30. Therefore, the electroless plating solution 50 penetrates into the porous layer 24, and the plating deposited metal 22 is deposited from the electroless plating solution 50 (see FIGS. 3D and 3E). As a result, the metal contact rate increases, and the electrical resistance can be made lower.

[0039] Next, a method for forming the recess 30 in the first insulating layer 71 will be described. The recess 30 is formed by heat-treating and curing the recessed shape 30a formed in the resin paste 73. Hereinafter, a method for forming the recessed shape 30a in the resin paste 73 will be described.

[0040] FIG. 4A is a schematic diagram showing a state in which the resin paste 73 is being applied while being separated from the resin paste 73 applied to the tip of the resin paste nozzle 74, and FIG. 4B is a schematic diagram showing a state in which the resin paste 73 is being applied while being in contact with the resin paste 73 applied to the tip of the resin paste nozzle 74. FIG. 5A is a schematic diagram showing a state in which the conductive particle paste 60 is being applied while being separated from the conductive particle paste 60 applied to the tip of the conductive particle paste nozzle 61, and FIG. 5B is a schematic diagram showing a state in which the conductive particle paste 60 is being applied while being in contact with the conductive particle paste 60 applied to the tip of the conductive particle paste nozzle 61.

[0041] (Method 1 for forming the recessed shape 30a) As shown in FIG. 4A, the resin paste 73 is applied onto the substrate 40 while being separated from the resin paste 73 applied to the tip of the resin paste nozzle 74. Next, as shown in FIG. 5A, before the resin paste 73 cures, the conductive particle paste 60 is applied onto the resin paste 73 while being separated from the conductive particle paste 60 applied to the tip of the conductive particle paste nozzle 61. The resin paste 73 forms a recessed shape 30a that becomes the recess 30 after heat treatment curing due to the self-weight of the conductive particle paste 60.

[0042] By utilizing the self-weight of the conductive particle paste 60 in this way, the recessed shape 30a can be formed in the resin paste 73. The recessed shape 30a of the resin paste 73 is formed in the recess 30 of the first insulating layer 71 by heat treatment curing.

[0043] (Method 2 for forming the recessed shape 30a) As shown in FIG. 4A, the resin paste 73 is applied onto the substrate 40 while being separated from the tip of the nozzle 74 for resin paste. Next, as shown in FIG. 5B, before the resin paste 73 cures, the conductive particle paste 60 is applied onto the resin paste 73 while being in contact with the tip of the nozzle 61 for conductive particle paste. The resin paste 73 is subjected to a downward pushing force acting from the nozzle 61 for conductive particle paste through the applied conductive particle paste 60, and further, due to the self-weight of the conductive particle paste 60, a recessed shape 30a that becomes the recess 30 after heat treatment curing is formed.

[0044] By utilizing the pushing force by the nozzle 61 for conductive particle paste and the self-weight of the conductive particle paste 60 in this way, the recessed shape 30a can be formed in the resin paste 73. After heat treatment curing, the recessed shape 30a of the resin paste 73 is formed in the recess 30 of the first insulating layer 71 by heat treatment curing.

[0045] (Method 3 for forming the recessed shape 30a) As shown in FIG. 4B, the resin paste 73 is applied onto the substrate 40 while being in contact with the tip of the nozzle 74 for resin paste. The resin paste 73 is subjected to a downward pushing force acting from the nozzle 74 for resin paste through the applied resin paste 73, and thereby, a recessed shape 30a that becomes the recess 30 after heat treatment curing is formed.

[0046] By the pushing force by the nozzle 74 for resin paste in this way, the recessed shape 30a can be formed in the resin paste 73. The recessed shape 30a of the resin paste 73 is formed in the recess 30 of the first insulating layer 71 by heat treatment curing.

[0047] (Method 3-1 for forming the recessed shape 30a) After the recessed shape 30a is formed in the resin paste 73 by the method 3 for forming the recessed shape 30a, the action of holding the recessed shape 30a of the resin paste 73 varies depending on the application method of the conductive particle paste 60.

[0048] First, as shown in FIG. 5A, before the resin paste 73 cures, the conductive particle paste 60 is applied onto the resin paste 73 while separating the tip of the nozzle 61 for the conductive particle paste from the applied conductive particle paste 60. The recessed shape 30a of the resin paste 73 is held by the self-weight of the conductive particle paste 60.

[0049] By utilizing the self-weight of the conductive particle paste 60 in this manner, the recessed shape 30a formed in the resin paste 73 can be held.

[0050] (Method 3-2 for forming the recessed shape 30a) Second, as shown in FIG. 5B, before the resin paste 73 cures, the conductive particle paste 60 is applied onto the resin paste 73 while bringing the tip of the nozzle 61 for the conductive particle paste into contact with the applied conductive particle paste 60. The recessed shape 30a of the resin paste 73 is subjected to a downward pushing force acting from the nozzle 61 for the conductive particle paste through the applied conductive particle paste 60, and is further held by the self-weight of the conductive particle paste 60.

[0051] By utilizing the pushing force by the nozzle 61 for the conductive particle paste and the self-weight of the conductive particle paste 60 in this manner, the recessed shape 30a formed in the resin paste 73 can be held.

[0052] Although the embodiments of the present invention have been described above, the present invention is not limited only to the configurations described in the above-described embodiments, and can be appropriately changed based on the description in the claims.

[0053] In addition, the following embodiments are also included in the scope of the present invention: a method for manufacturing a conductive circuit according to claim 7 having the features of claim 8; a method for manufacturing a conductive circuit according to claim 7 or 8 having the features of claim 9.

[0054] An example of the type of coating, the contact resistance of the coating, and the volume resistance of the conductor in the test body is shown in Table 1 below.

[0055]

Table 1

[0056] As the conductive particle paste used for fabricating the test piece, a paste (copper paste XCH9207 for air curing manufactured by Namics Corporation) containing copper powder (corresponding to conductive particles) with an average particle diameter of 3 μm, a binder, and a solvent (water) was prepared. A resin paste for forming a coating was applied on a substrate, and before the resin paste hardened, the conductive particle paste was applied on the resin paste while separating the tip of the nozzle for the conductive particle paste. A concave shape was formed in the resin paste due to the self-weight of the conductive particle paste. Then, in an air atmosphere, heating was performed at a temperature of 120°C for 20 min to dry the resin paste and the conductive particle paste. As a result, a concave portion was formed in a part of the surface of the first insulating layer, and a porous layer containing conductive particles was formed.

[0057] As the electroless plating solution, electroless copper plating solution OPC Copper HFS manufactured by Okuno Pharmaceutical Co., Ltd. was prepared. That is, three solutions of OPC Copper HFS-M, OPC Copper HFS-A, and OPC Copper HFS-C manufactured by Okuno Pharmaceutical Co., Ltd. were mixed at a mixing ratio of 150:60:4 to prepare an electroless copper plating solution. The obtained electroless copper plating solution was applied into the concave portion using an inkjet device to impregnate the inside of the porous layer, and then left in an air atmosphere at 25°C for 120 minutes to perform electroless copper plating.

[0058] As a result of the electroless copper plating, copper particles (corresponding to plating-deposited metal particles) with an average particle diameter of 35 nm were deposited on the surface of the copper powder dispersed inside the porous layer. Since the deposited copper particles electrically connected the copper powders to each other, the dried porous layer became a conductor. After the electroless copper plating was completed, the resin plate-shaped member was washed with water and dried.

[0059] Then, the resin paste was coated on the conductor and heated at 120 °C for 20 min in an air atmosphere to dry the resin paste. As a result, a test body equipped with a conductive circuit was obtained.

[0060] Next, the resistance value of the conductive circuit of the obtained test body was measured. The resistance value was measured using a nanovoltmeter 2182A manufactured by Keithley Instruments, Inc. and a 6221 type AC / DC current generator manufactured by Keithley Instruments, Inc. Under the conditions of a source power supply of ±100 mA and a measurement current of 100 mA, the electrical resistance value between both ends of the linear wiring was measured by the four-terminal method. Then, the measurement result was substituted into the following formula Volume resistivity (Ω·cm) = Electrical resistance value (Ω) × Cross-sectional area of the wiring of the conductive circuit (cm 2 ) / Length of the wiring of the conductive circuit (cm) to calculate the volume resistivity.

[0061] As a result of manufacturing the test body and calculating the volume resistivity, it was confirmed that a conductive circuit with low electrical resistance can be manufactured while ensuring insulation. Furthermore, it was confirmed that a conductive circuit with low electrical resistance can be manufactured even with a heat treatment at a temperature lower than the heat treatment temperature disclosed in Patent Document 1.

Description of symbols

[0062] 10 Conductive circuit 20 Conductor 21 Conductive particles 22 Electroless deposition metal, electroless deposition metal particles 23 Cured reaction product 24 Porous layer 30 Recess 30a Depression shape 40 Substrate 50 Electroless plating solution 60 Conductive particle paste 61 Nozzle for conductive particle paste 70 Resin insulation layer 71 First insulation layer 72 Second insulation layer 73 Resin paste Nozzle for resin paste

Claims

1. A resin paste forming a first insulating layer in contact with a substrate is applied onto the substrate, and a conductive particle paste in which conductive particles are dispersed in a dispersion liquid is applied onto the resin paste and then heat-treated and cured in an air atmosphere to form a concave portion in a part of the surface of the first insulating layer and to form a porous layer containing the conductive particles. An electroless plating solution to be impregnated into the porous layer is held in the concave portion of the first insulating layer, and the conductive particles dispersed inside the porous layer are connected to each other by a plating-deposited metal deposited from the electroless plating solution, and a conductor is formed by the porous layer. A method for manufacturing a conductive circuit, wherein the resin paste is applied onto the conductor and then heat-treated and cured in an air atmosphere to form a second insulating layer covering the conductor.

2. The resin paste is applied onto the substrate, and before the resin paste cures, the conductive particle paste is applied onto the resin paste while separating the tip of a nozzle for the conductive particle paste from the applied conductive particle paste, and a concave shape that becomes the concave portion after heat treatment and curing is formed in the resin paste by the weight of the conductive particle paste. The method for manufacturing a conductive circuit according to claim 1.

3. The resin paste is applied onto the substrate, and before the resin paste cures, the conductive particle paste is applied onto the resin paste while bringing the tip of a nozzle for the conductive particle paste into contact with the applied conductive particle paste, and a concave shape that becomes the concave portion after heat treatment and curing is formed in the resin paste. The method for manufacturing a conductive circuit according to claim 1.

4. The resin paste is applied onto the substrate while bringing the tip of a nozzle for the resin paste into contact with the applied resin paste, and a concave shape that becomes the concave portion after heat treatment and curing is formed in the resin paste. The method for manufacturing a conductive circuit according to claim 1.

5. Before the resin paste cures, the conductive particle paste is applied onto the resin paste while separating the tip of a nozzle for the conductive particle paste from the applied conductive particle paste, and the concave shape of the resin paste is maintained by the weight of the conductive particle paste. The method for manufacturing a conductive circuit according to claim 4.

6. Before the resin paste cures, while bringing the tip of the nozzle for the conductive particle paste into contact with the conductive particle paste applied to the resin paste, the conductive particle paste is applied onto the resin paste, and the recessed shape of the resin paste is maintained. The method for manufacturing a conductive circuit according to claim 4.

7. The method for manufacturing a conductive circuit according to any one of claims 1 to 6, wherein the resin paste comprises a polyamide resin, polyvinyl chloride (PVC), or an epoxy resin.

8. The method for manufacturing a conductive circuit according to any one of claims 1 to 6, wherein the conductive particles of the conductive particle paste have a particle diameter of 1 μm or more and 1000 μm or less.

9. The method for manufacturing a conductive circuit according to any one of claims 1 to 6, wherein the conductive particle paste is applied onto the resin paste so that the porous layer does not protrude from the recess of the first insulating layer.

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