Loop Formation Method

Abstract

This circuit forming method includes a first wiring forming step for forming a first metal wiring on a resin layer and a second wiring forming step for forming a second metal wiring on the first metal wiring, the Young's modulus of the first metal wiring and the Young's modulus of the second metal wiring being different from each other.

Description

[Technical Field]

[0001] The present invention relates to a circuit forming method for forming metal wiring on a resin layer. [Background technology]

[0002] The following Patent Document describes a circuit forming method for forming metal wiring on a resin layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-130553 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present specification is to appropriately form metal wiring. [Means for solving the problem]

[0005] In order to solve the above problems, the present specification provides a method for manufacturing a resin layer having a thickness of 100 μm or more. A pair of ends spaced apart from each other a first wiring forming step of forming a first metal wiring; a pair First metal wiring the spaced apart ends of On top a pair The method includes a second wiring forming step of forming a second metal wiring, and a component mounting step of mounting an electronic component on the second metal wiring, wherein the Young's modulus of the second metal wiring is lower than that of the first metal wiring, and in the second wiring forming step, the second metal wiring is formed along an upper surface of the first metal wiring, with a width wider than that of the first metal wiring, and with a predetermined length that is a part of the extending direction of the first metal wiring and includes a planned mounting position of an electrode of the electronic component, and in the component mounting step, the electrode of the electronic component is in contact with the second metal wiring on the first metal wiring and is positioned directly above the first metal wiring via the second metal wiring. At the same time, the component body of the electronic component is located between the ends of the pair of first metal wirings, between the ends of the pair of second metal wirings, and directly above the dispensed thermosetting resin.A circuit forming method is disclosed in which the circuit is mounted as follows. [Effects of the Invention]

[0006] In the present disclosure, a second metal wiring is formed on a first metal wiring, and the Young's modulus of the first metal wiring is different from that of the second metal wiring. In this way, by forming two wirings with different Young's moduli in a double layer, the metal wiring can be appropriately formed. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a circuit forming device. [Figure 2] FIG. 2 is a block diagram showing a control device. [Figure 3] FIG. 2 is a cross-sectional view showing a circuit in a state where a resin laminate is formed. [Figure 4] FIG. 2 is a cross-sectional view showing a circuit in a state where wiring is formed on a resin laminate. [Figure 5] FIG. 10 is a cross-sectional view showing a circuit in a state where a conductive resin paste is applied onto wiring. [Figure 6] FIG. 2 is a cross-sectional view showing a circuit with electronic components mounted thereon. [Figure 7] FIG. 2 is a cross-sectional view showing a circuit in which electronic components are fixed with resin. [Figure 8] FIG. 10 is a cross-sectional view showing a circuit in a state where a wiring is disconnected. [Figure 9] FIG. 10 is a cross-sectional view showing a circuit in which conductive resin paste has been applied linearly onto wiring. [Figure 10] FIG. 10 is a plan view showing a circuit in which conductive resin paste has been applied linearly onto wiring. [Figure 11] FIG. 2 is a cross-sectional view showing a circuit with electronic components mounted thereon. [Figure 12] FIG. 2 is a cross-sectional view showing a circuit in which electronic components are fixed with resin. [Figure 13] FIG. 10 is a cross-sectional view showing a circuit in a state where a first wiring is disconnected and a second wiring functions as a bypass. DETAILED DESCRIPTION OF THE INVENTION

[0008] FIG. 1 shows a circuit forming apparatus 10. The circuit forming apparatus 10 includes a conveying device 20, a first modeling unit 22, a second modeling unit 24, a third modeling unit 25, a fourth modeling unit 26, a mounting unit 27, and a control device (see FIG. 2) 28. The conveying device 20, the first modeling unit 22, the second modeling unit 24, the third modeling unit 25, the fourth modeling unit 26, and the mounting unit 27 are arranged on a base 29 of the circuit forming apparatus 10. The base 29 has a generally rectangular shape, and in the following description, the longitudinal direction of the base 29 will be referred to as the X-axis direction, the lateral direction of the base 29 as the Y-axis direction, and the direction perpendicular to both the X-axis direction and the Y-axis direction as the Z-axis direction.

[0009] The transport device 20 includes an X-axis slide mechanism 30 and a Y-axis slide mechanism 32. The X-axis slide mechanism 30 includes an X-axis slide rail 34 and an X-axis slider 36. The X-axis slide rail 34 is disposed on a base 29 so as to extend in the X-axis direction. The X-axis slider 36 is held by the X-axis slide rail 34 so as to be slidable in the X-axis direction. The X-axis slide mechanism 30 also includes an electromagnetic motor (see FIG. 2) 38, and the X-axis slider 36 is moved to any position in the X-axis direction by the drive of the electromagnetic motor 38. The Y-axis slide mechanism 32 also includes a Y-axis slide rail 50 and a stage 52. The Y-axis slide rail 50 is disposed on the base 29 so as to extend in the Y-axis direction and is movable in the X-axis direction. One end of the Y-axis slide rail 50 is connected to the X-axis slider 36. The stage 52 is held by the Y-axis slide rail 50 so as to be slidable in the Y-axis direction. Furthermore, the Y-axis slide mechanism 32 has an electromagnetic motor (see FIG. 2) 56, and the stage 52 moves to any position in the Y-axis direction by driving the electromagnetic motor 56. As a result, the stage 52 moves to any position on the base 29 by driving the X-axis slide mechanism 30 and the Y-axis slide mechanism 32.

[0010] The stage 52 has a base 60, a holding device 62, and an elevating device 64. The base 60 is formed in a flat plate shape, and a substrate is placed on the upper surface. The holding devices 62 are provided on both sides of the base 60 in the X-axis direction. The holding devices 62 clamp both edges of the substrate in the X-axis direction placed on the base 60, thereby fixedly holding the substrate. The elevating device 64 is disposed below the base 60, and raises and lowers the base 60.

[0011] The first modeling unit 22 is a unit that models wiring on a substrate placed on the base 60 of the stage 52, and includes a first printing unit 72 and a baking unit 74. The first printing unit 72 has an inkjet head (see FIG. 2) 76 that ejects metal ink in a linear pattern. The metal ink is a dispersion of nanometer-sized metal particles, such as silver particles, in a solvent. The surfaces of the metal particles are coated with a dispersant to prevent aggregation in the solvent. The inkjet head 76 ejects the metal ink from multiple nozzles using, for example, a piezoelectric method using piezoelectric elements.

[0012] The baking unit 74 has an infrared irradiation device 78 (see FIG. 2). The infrared irradiation device 78 is a device that irradiates the ejected metal ink with infrared rays, and the metal ink irradiated with infrared rays is baked to form wiring. Note that baking of metal ink is a phenomenon in which, by applying energy, the solvent is vaporized and the protective film on the metal particles, i.e., the dispersant, is decomposed, and the metal particles come into contact or fuse together, thereby increasing the conductivity. Then, by baking the metal ink, metal wiring is formed.

[0013] The second modeling unit 24 is a unit that models a resin layer on a substrate placed on the base 60 of the stage 52, and has a second printing unit 84 and a curing unit 86. The second printing unit 84 has an inkjet head (see FIG. 2) 88 that ejects ultraviolet curable resin. The ultraviolet curable resin is a resin that hardens when irradiated with ultraviolet light. The inkjet head 88 may be, for example, a piezo type that uses a piezoelectric element, or a thermal type that heats the resin to generate bubbles and ejects the resin from multiple nozzles.

[0014] The curing unit 86 has a flattening device (see FIG. 2) 90 and an irradiation device (see FIG. 2) 92. The flattening device 90 flattens the upper surface of the ultraviolet curing resin discharged by the inkjet head 88, for example, by leveling the surface of the ultraviolet curing resin and scraping off excess resin with a roller or blade, thereby making the thickness of the ultraviolet curing resin uniform. The irradiation device 92 is equipped with a mercury lamp or LED as a light source and irradiates the discharged ultraviolet curing resin with ultraviolet light. This hardens the discharged ultraviolet curing resin, forming a resin layer.

[0015] The third modeling unit 25 is a unit that models connections between electrodes and wiring of electronic components on a substrate placed on the base 60 of the stage 52, and includes a third printing unit 100 and a first heating unit 102. The third printing unit 100 includes a dispenser 106 (see FIG. 2) that dispenses conductive resin paste. The conductive resin paste is a resin that hardens when heated at a relatively low temperature and has micrometer-sized metal particles dispersed in it. The metal particles are in the form of flakes, and the viscosity of the conductive resin paste is relatively high compared to metal ink. The amount of conductive resin paste dispensed by the dispenser 106 is controlled by the inner diameter of the needle, the pressure during dispensing, and the dispensing time.

[0016] The first heating unit 102 has a heater 108 (see FIG. 2). The heater 108 is a device that heats the conductive resin paste applied by the dispenser 106, and the resin in the heated conductive resin paste hardens. At this time, the resin in the conductive resin paste hardens and shrinks, causing the flake-shaped metal particles dispersed in the resin to come into contact with each other. This allows the conductive resin paste to exhibit conductivity. The resin in the conductive resin paste is an organic adhesive, and exhibits adhesive strength when hardened by heating.

[0017] The fourth modeling unit 26 is a unit that models resin for fixing the peripheries of electronic components (described later), and includes a fourth printing unit 110 and a second heating unit 112. The fourth printing unit 110 includes an inkjet head 116 (see FIG. 2) that ejects thermosetting resin. Thermosetting resin is a resin that hardens when heated. The inkjet head 116 is, for example, a piezo type that uses a piezoelectric element. The second heating unit 112 includes a heater 118 (see FIG. 2). The heater 118 is a device that heats the ejected thermosetting resin, and the heated thermosetting resin hardens.

[0018] Furthermore, mounting unit 27 is a unit that mounts electronic components on a substrate placed on base 60 of stage 52, and has supply section 120 and mounting section 122. Supply section 120 has a plurality of tape feeders (see FIG. 2) 124 that feed taped electronic components one by one, and supplies the electronic components at a supply position. Note that supply section 120 is not limited to tape feeders 124, and may also be a tray-type supply device that picks up and supplies electronic components from a tray. Furthermore, supply section 120 may be configured to include both tape-type and tray-type supply devices, or other types of supply devices.

[0019] The placing unit 122 has a placing head 126 (see FIG. 2) and a moving device 128 (see FIG. 2). The placing head 126 has a suction nozzle (not shown) for suctioning and holding electronic components. The suction nozzle suctions and holds the electronic components by air suction when negative pressure is supplied from a positive / negative pressure supplying device (not shown). The positive / negative pressure supplying device then supplies a slight positive pressure to the suction nozzle, which then detaches the electronic components. The moving device 128 also moves the placing head 126 between the position where the tape feeder 124 supplies electronic components and the board placed on the base 60. As a result, in the placing unit 122, the electronic components supplied from the tape feeder 124 are held by the suction nozzle, and the electronic components held by the suction nozzle are placed on the board.

[0020] 2, the control device 28 includes a controller 130 and a plurality of drive circuits 132. The plurality of drive circuits 132 are connected to the electromagnetic motors 38, 56, the holding device 62, the lifting device 64, the inkjet head 76, the infrared irradiation device 78, the inkjet head 88, the flattening device 90, the irradiation device 92, the dispenser 106, the heater 108, the inkjet head 116, the heater 118, the tape feeder 124, the mounting head 126, and the moving device 128. The controller 130 includes a CPU, ROM, RAM, etc., and is primarily a computer, and is connected to the plurality of drive circuits 132. As a result, the controller 130 controls the operations of the transport device 20, the first modeling unit 22, the second modeling unit 24, the third modeling unit 25, the fourth modeling unit 26, and the mounting unit 27.

[0021] In the circuit forming apparatus 10, a resin laminate is formed on the substrate 70 (see FIG. 3) by the above-described configuration, and wiring is formed on the upper surface of the resin laminate. Then, electrodes of electronic components are electrically connected to the wiring via the conductive resin paste, and the electronic components are fixed by the resin.

[0022] Specifically, the substrate 70 is set on the base 60 of the stage 52, and the stage 52 is moved below the second modeling unit 24. Then, in the second modeling unit 24, a resin laminate 150 is formed on the substrate 70, as shown in Fig. 3. The resin laminate 150 is formed by repeatedly discharging an ultraviolet curable resin from the inkjet head 88 and irradiating the discharged ultraviolet curable resin with ultraviolet rays by the irradiation device 92.

[0023] More specifically, in the second printing unit 84 of the second modeling unit 24, the inkjet head 88 ejects a thin film of ultraviolet curable resin onto the upper surface of the substrate 70. Then, after the ultraviolet curable resin has been ejected in the form of a thin film, the ultraviolet curable resin is flattened by a flattening device 90 in the curing unit 86 so that the film thickness of the ultraviolet curable resin becomes uniform. Then, the irradiation device 92 irradiates the thin film of ultraviolet curable resin with ultraviolet rays. As a result, a thin film resin layer 152 is formed on the substrate 70.

[0024] Next, the inkjet head 88 ejects a thin film of ultraviolet curable resin onto the thin film resin layer 152. The thin film of ultraviolet curable resin is then flattened by a flattening device 90, and an irradiation device 92 irradiates the ejected thin film of ultraviolet curable resin with ultraviolet light, thereby laminating thin film resin layers 152 on thin film resin layers 152. In this manner, the ejection of ultraviolet curable resin onto the thin film resin layer 152 and the irradiation of ultraviolet light are repeated, and a plurality of resin layers 152 are laminated, thereby forming a resin laminate 150.

[0025] Once the resin laminate 150 is formed by the above-described procedure, the stage 52 is moved to below the first modeling unit 22. Then, in the first printing unit 72 of the first modeling unit 22, the inkjet head 76 ejects metal ink 154 in a line shape according to the circuit pattern onto the upper surface of the resin laminate 150, as shown in FIG. 4. Next, in the baking unit 74 of the first modeling unit 22, the infrared irradiation device 78 irradiates infrared rays onto the metal ink 154 ejected according to the circuit pattern. As a result, the metal ink 154 is baked, and wiring 156 is formed on the resin laminate 150.

[0026] Next, after the wiring 156 is formed on the resin laminate 150, the stage 52 is moved below the third modeling unit 25. Then, in the third printing section 100 of the third modeling unit 25, the dispenser 106 dispenses conductive resin paste 157 onto the end of the wiring 156, as shown in FIG. 5. After the conductive resin paste 157 has been dispensed onto the end of the wiring 156 in this manner, the stage 52 is moved below the mounting unit 27. In the mounting unit 27, an electronic component 160 (see FIG. 6) is supplied by the tape feeder 124, and the electronic component 160 is held by the suction nozzle of the mounting head 126. The electronic component 160 is composed of a component body 162 and two electrodes 164 disposed on the lower surface of the component body 162. Then, the mounting head 126 is moved by the moving device 128, and the electronic component 160 held by the suction nozzle is mounted on the upper surface of the resin laminate 150, as shown in FIG. 6. At this time, electronic component 160 is attached to the upper surface of resin laminate 150 so that electrode 164 of electronic component 160 comes into contact with conductive resin paste 157 dispensed onto wiring 156. Note that the lower surface of electrode 164 protrudes downward from the lower surface of component body 162, and therefore electrode 164 comes into good contact with conductive resin paste 157.

[0027] Once the electronic component 160 is mounted on the resin laminate 150 in this manner, the stage 52 is moved to below the third modeling unit 25. Then, in the first heating section 102 of the third modeling unit 25, the conductive resin paste 157 is heated by the heater 108. As a result, the conductive resin paste 157 exhibits conductivity, and the electrodes 164 are electrically connected to the wiring 156 via the conductive resin paste 157. Furthermore, the adhesive force of the conductive resin paste 157 causes the electronic component 160 to adhere to the wiring 156, thereby fixing the electronic component 160 to the resin laminate 150.

[0028] Once the electronic component 160 is connected to the wiring in this manner, the stage 52 is moved below the fourth modeling unit 26. Then, in the fourth printing section 110 of the fourth modeling unit 26, the inkjet head 116 ejects the thermosetting resin 170 between the lower surface of the component body 162 of the electronic component 160 and the upper surface of the resin laminate 150, as shown in FIG. 7 . This causes the thermosetting resin 170 to be sealed between the upper surface of the resin laminate 150 and the lower surface of the component body 162 of the electronic component 160. In other words, the thermosetting resin 170 is sealed between the upper surface of the resin laminate 150 and the lower surface of the component body 162. Furthermore, the inkjet head 116 ejects the thermosetting resin 170 around the electronic component 160 so as to cover the side surfaces of the component body 162 of the electronic component 160. Then, in the second heating section 112, the thermosetting resin 170 is heated by the heater 118, so that the thermosetting resin 170 is sealed between the upper surface of the resin laminate 150 and the lower surface of the component body 162, and hardens while covering the side surfaces of the component body 162. As a result, the electronic component 160 attached to the upper surface of the resin laminate 150 is fixed by the hardened resin.

[0029] In this manner, in the circuit forming apparatus 10, the resin laminate 150 is formed on the substrate 70, and the wiring 156 is formed on the upper surface of the resin laminate. Then, the electrodes 164 of the electronic component 160 are electrically connected to the wiring via the conductive resin paste 157, and the electronic component is fixed with the thermosetting resin, thereby forming a circuit. However, because the circuit is formed using multiple materials, such as UV-curable resin, metal ink, conductive resin paste, and thermosetting resin, the differences in the linear expansion coefficients of these materials may cause stress in the wiring 156 during temperature changes, which may result in disconnection of the wiring 156. In other words, because the expansion and contraction amounts of each material differ during temperature changes, stress may be generated in the wiring 156 during temperature changes, which may result in disconnection of the wiring 156. In particular, because the electronic component 160 barely expands or contracts during temperature changes, stress is generated in the wiring 156 starting from the mounting position of the electronic component 160. Therefore, as shown in FIG. 8, there is a high possibility that a crack 180 will occur in the wiring 156 near the connection position to the electrode 164 of the electronic component 160, causing the wiring 156 to break.

[0030] In view of this, the circuit forming apparatus 10 forms a second wiring different from the wiring 156 on the wiring 156 to ensure the supply of power to the electronic component 160. Specifically, as in the conventional method, a resin laminate 150 is formed using an ultraviolet-curable resin, and the wiring 156 is formed on the upper surface of the resin laminate 150 using a metal ink. Then, in the third printing unit 100 of the third modeling unit 25, when the dispenser 106 dispenses the conductive resin paste 157 onto the wiring 156, as shown in FIG. 9 , the conductive resin paste 157 is dispensed linearly not only onto the end of the wiring 156, i.e., the intended mounting position of the electrode 164 of the electronic component 160, but also onto the wiring 156 a predetermined length from the end. In other words, the conductive resin paste 157 having a predetermined length is dispensed linearly from the end of the wiring 156 along the upper surface of the wiring 156. At this time, as shown in FIG. 10 , the conductive resin paste 157 is dispensed onto the upper surface of the wiring 156 so as to be wider than the wiring 156.

[0031] When the conductive resin paste 157 is dispensed onto the upper surface of the wiring 156 in this manner, the mounting unit 27 mounts the electronic component 160 on the upper surface of the resin laminate 150 so that the electrodes 164 of the electronic component 160 contact the ends of the conductive resin paste 157 dispensed linearly onto the wiring, as shown in FIG. 11 . Then, the conductive resin paste 157 is heated by the heater 108 in the first heating section 102 of the third modeling unit 25. As a result, the conductive resin paste 157 exhibits conductivity, so that the electrodes 164 are electrically connected to the wiring 156 via the conductive resin paste 157, and a second wiring made of the conductive resin paste 157 and wider than the wiring 156 is formed on the wiring 156.

[0032] After the second wiring made of the conductive resin paste 157 is formed on the wiring 156 in this manner, the fourth printing unit 110 of the fourth modeling unit 26 ejects a thermosetting resin 170 between the lower surface of the component body 162 of the electronic component 160 and the upper surface of the resin laminate 150, as well as around the electronic component 160, as shown in FIG. 12 . Then, in the second heating unit 112, the thermosetting resin 170 is heated by the heater 118, whereby the thermosetting resin 170 is sealed between the upper surface of the resin laminate 150 and the lower surface of the component body 162 and hardens while covering the side surfaces of the component body 162. This forms a circuit in which the electronic component 160 attached to the upper surface of the resin laminate 150 is fixed by the hardened resin.

[0033] In this way, in a circuit in which second wiring made of conductive resin paste 157 is formed on wiring 156, i.e., first wiring made of metal ink 154, power supply to electronic component 160 can be ensured by the second wiring even if the first wiring is broken. Specifically, because the first wiring is formed of metal ink 154 and the second wiring is formed of conductive resin paste 157, the Young's modulus of the first wiring is different from that of the second wiring. Young's modulus is a proportional constant between strain and stress in the elastic range, and is the ratio of stress to strain. Therefore, when an object with a high Young's modulus and an object with a low Young's modulus are deformed with the same stress, the object with the low Young's modulus deforms more than the object with the high Young's modulus. In other words, an object with a low Young's modulus is easily deformed, while an object with a high Young's modulus is difficult to deform. The Young's modulus of the first wiring made of metal ink 154 is approximately 80 GPa. On the other hand, the Young's modulus of the second wiring made of conductive resin paste 157 is approximately 1 to 100 MPa. That is, the Young's modulus of the second wiring made of conductive resin paste 157 is lower than the Young's modulus of the first wiring made of metal ink 154, and the second wiring made of conductive resin paste 157 is more easily deformed than the first wiring made of metal ink 154. On the other hand, the Young's modulus of the first wiring made of metal ink 154 is higher than the Young's modulus of the second wiring made of conductive resin paste 157, and the first wiring made of metal ink 154 is less likely to deform than the second wiring made of conductive resin paste 157.

[0034] Therefore, even if the first wiring made of metal ink 154 expands and contracts during a temperature change, the first wiring made of metal ink 154 is unlikely to deform, and as shown in FIG. 13 , cracks 180 may occur in the first wiring made of metal ink 154, resulting in disconnection. On the other hand, even if the second wiring made of conductive resin paste 157 expands and contracts during a temperature change, the second wiring made of conductive resin paste 157 is likely to deform and is therefore unlikely to be disconnected due to expansion and contraction. Thus, even if the first wiring made of metal ink 154 is disconnected during a temperature change, the second wiring formed on the first wiring will not be disconnected. Therefore, the second wiring functions as a bypass, thereby ensuring the supply of power to electronic component 160. In other words, by forming a second wiring having a lower Young's modulus than the first wiring on top of the first wiring, the second wiring can ensure the supply of power to electronic component 160.

[0035] Furthermore, the width of the second wiring made of conductive resin paste 157 is wider than the width of the first wiring made of metal ink 154. Therefore, the second wiring made of conductive resin paste 157 covers the first wiring made of metal ink 154 in the width direction, thereby more suitably ensuring the supply of power to electronic component 160.

[0036] Furthermore, the second wiring made of conductive resin paste 157 is not formed over the entire first wiring made of metal ink 154, but only around the connection portion to electrode 164. In other words, the second wiring made of conductive resin paste 157 is formed only in locations where there is a high possibility of breakage of the first wiring made of metal ink 154. This allows for a reduction in the time and cost required to form the second wiring, compared to when the second wiring is formed over the entire first wiring.

[0037] 2, the controller 130 of the control device 28 has a first wiring forming unit 190 and a second wiring forming unit 192. The first wiring forming unit 190 is a functional unit for forming a first wiring using the metal ink 154. The second wiring forming unit 192 is a functional unit for forming a second wiring using the conductive resin paste 157 on the first wiring using the metal ink 154.

[0038] In the above examples, the resin laminate 150 is an example of a resin layer. The first wiring formed by the metal ink 154 is an example of a first metal wiring. The second wiring formed by the conductive resin paste 157 is an example of a second metal wiring. The electronic component 160 is an example of a component. The process performed by the first wiring forming unit 190 is an example of a first wiring forming step. The process performed by the second wiring forming unit 192 is an example of a second wiring forming step.

[0039] The present invention is not limited to the above-described embodiment, and can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. For example, in the above-described embodiment, the second wiring made of conductive resin paste 157 is formed on the first wiring made of metal ink 154, but the first wiring made of metal ink 154 may be formed on the second wiring made of conductive resin paste 157. In other words, a wiring with a high Young's modulus may be formed on a wiring with a low Young's modulus.

[0040] Furthermore, in the above embodiment, the second wiring made of conductive resin paste 157 is formed only on a portion of the first wiring made of metal ink 154, but the second wiring made of conductive resin paste 157 may be formed on the entire first wiring made of metal ink 154.

[0041] Furthermore, in the above embodiment, the second wiring made of conductive resin paste 157 is formed to be wider than the first wiring made of metal ink 154, but the second wiring made of conductive resin paste 157 may be formed to be narrower than the first wiring made of metal ink 154 or to be the same width as the first wiring.

[0042] Furthermore, in the above embodiment, the second wiring is formed around the connection portion of the first wiring to the electrode of the electronic component 160, but the second wiring may also be formed around the connection portion to other components, such as vias, connection pins, etc.

[0043] Furthermore, in the above embodiment, the first wiring is formed from metal ink 154 and the second wiring is formed from conductive resin paste 157, but various materials can be used as long as they are capable of forming metal wiring.

[0044] Furthermore, in the above embodiment, the resin laminate 150 is made of an ultraviolet curable resin, but it may be made of a thermosetting resin, a two-component mixed curable resin, a thermoplastic resin, or the like.

[0045] Furthermore, in the above embodiment, the conductive resin paste 157 is dispensed by the dispenser 106, but it may be transferred by a transfer device or the like. Furthermore, the conductive resin paste 157 may be printed by screen printing. [Explanation of symbols]

[0046] 150: Resin laminate (resin layer) 154: Metal ink (first wiring) 157: Conductive resin paste (second wiring) 160: Electronic component (component) 190: First wiring forming unit (first wiring forming process) 192: Second wiring forming unit (second wiring forming process)

Claims

1. a first wiring forming step of forming a pair of first metal wirings on the resin layer, the ends of the first metal wirings being spaced apart from each other; a second wiring forming step of forming a pair of second metal wirings on the ends of the pair of first metal wirings that are spaced apart from each other; a component mounting step of mounting an electronic component on the second metal wiring; Including, the Young's modulus of the second metal wiring is lower than the Young's modulus of the first metal wiring; In the second wiring forming step, the second metal wiring is formed along an upper surface of the first metal wiring, has a width wider than that of the first metal wiring, and has a predetermined length that is a part of the first metal wiring in an extending direction and includes a position where an electrode of the electronic component is to be mounted; a circuit forming method, wherein in the component mounting step, the electronic component is mounted so that the electrodes of the electronic component contact the second metal wiring on the first metal wiring and are positioned directly above the first metal wiring via the second metal wiring, and the component body of the electronic component is positioned between the ends of the pair of first metal wirings and between the ends of the pair of second metal wirings and directly above the dispensed thermosetting resin.

2. one of the first metal wiring and the second metal wiring is formed from a metal-containing liquid containing nanometer-sized metal fine particles; 2. The circuit forming method according to claim 1, wherein the other of the first metal wiring and the second metal wiring is formed from a metal-containing liquid containing metal fine particles of micrometer size.

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