Method for forming an electrical circuit

Abstract

To ensure proper electrical connection between an electronic component and a metal wiring.SOLUTION: An electric circuit forming method includes a mounting step of disposing a resin layer on a base, and mounting an electronic component so as to be electrically connected to a metal wiring formed on the resin layer, a coating step of applying a curable resin onto the resin layer so as to come into contact with the main body of the electronic component, and a pressing step of pressing the mounted electronic components relatively against the resin layer by a pressing body in the mounting step, and in the pressing step, the electronic component is relatively pressed by the pressing body while heating the curable resin with the resin layer surrounding the space between the base and the pressing body from the side.SELECTED DRAWING: Figure 13

Description

Technical Field

[0001] The present invention relates to an electric circuit forming method and the like in which an electronic component is mounted so as to be electrically connected to a metal wiring formed on a resin layer, a curable resin is applied onto the resin layer so as to contact the component body of the electronic component, and then the electronic component is pressed against the resin layer relatively.

Background Art

[0002] It is possible to form an electric circuit by using a three-dimensional shaping apparatus described in Patent Document 1 below.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an electric circuit is formed by a three-dimensional shaping apparatus, an electronic component is mounted so as to be electrically connected to a metal wiring, a curable resin is applied onto the resin layer so as to contact the component body of the electronic component, and then the electronic component may be pressed by a pressing body. In such a case, it is an issue to appropriately ensure the electrical connection between the electronic component and the metal wiring.

Means for Solving the Problems

[0005] To solve the above problems, this specification includes a mounting step of mounting an electronic component so as to be electrically connected to metal wiring formed on a resin layer disposed on a base, a coating step of applying a curable resin onto the resin layer so as to be in contact with the component body of the electronic component, and a pressing step of pressing the electronic component mounted in the mounting step against the resin layer with a pressing body, wherein the pressing step involves heating the curable resin while pressing the electronic component against the pressing body with the pressing body while surrounding the resin layer from the side between the base and the pressing body. The process further includes a heating step prior to the pressing step, in which the curable resin is heated while the resin layer is surrounded from the side between the base and the pressing body, and the heating step is performed by heating the curable resin while the resin layer is surrounded from the side between the base and the pressing body until the temperature difference between the pressing body and the resin layer becomes less than or equal to a set temperature difference. A method for forming an electrical circuit is disclosed.

[0006] [Effects of the Invention]

[0007] In this disclosure, the resin layer is heated while the curable resin is heated, and the electronic component is pressed relative to the resin layer by the pressing body, with the base on which the resin layer is disposed and the pressing body surrounding the resin layer from the side. In this disclosure, the pressing body is made up of multiple laminated members with different coefficients of thermal expansion, and these multiple members include at least a first elastic member that is pressed relative to the resin layer, and a low coefficient of thermal expansion member laminated on top of the first elastic member and having a lower coefficient of thermal expansion than the first elastic member. This makes it possible to properly ensure the electrical connection between the electronic component and the metal wiring when the electronic component is pressed by the pressing body. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing a circuit forming apparatus. [Figure 2] Control device branch. [Figure 3] This is a cross-sectional view showing a circuit board in a state where a resin laminate has been formed. [Figure 4] This is a cross-sectional view showing a circuit board with wiring formed on a resin laminate. [Figure 5] This is a cross-sectional view showing a circuit board in which a resin laminate is formed on top of another resin laminate. [Figure 6] This is a cross-sectional view showing a circuit board with conductive paste applied over the wiring. [Figure 7] This is a cross-sectional view showing a circuit board in which a thermosetting resin has been applied to a resin layer. [Figure 8] This is a cross-sectional view showing a circuit board with electronic components mounted on it. [Figure 9] This is a cross-sectional view showing a circuit board with electronic components pressed against a resin laminate. [Figure 10] This is a cross-sectional view showing a circuit board with a thermosetting resin coating applied around electronic components. [Figure 11] This is a cross-sectional view showing a circuit board before electronic components are pressed against it by a rubber plate with a sponge on its underside. [Figure 12] This is a cross-sectional view showing a circuit board being heated with the base and rubber plate surrounded from the side by a resin laminate. [Figure 13] This is a cross-sectional view showing a circuit board in which the base and the rubber plate surround the resin laminate from the side, and the electronic components are pressed against the resin laminate by the rubber plate while being heated. [Figure 14] This is a schematic diagram showing the pressing body of the second embodiment. [Figure 15] This is a schematic diagram showing the pressing body of the third embodiment. [Modes for carrying out the invention]

[0009] Figure 1 shows the circuit forming apparatus 10. The circuit forming apparatus 10 comprises a transport device 20, a first forming unit 22, a second forming unit 23, a third forming unit 24, a fourth forming unit 25, a pressing unit 26, a mounting unit 27, and a control device (see Figure 2) 28. The transport device 20, the first forming unit 22, the second forming unit 23, the third forming unit 24, the fourth forming unit 25, the pressing unit 26, and the mounting unit 27 are arranged on the base 29 of the circuit forming apparatus 10. The base 29 is generally rectangular in shape, and in the following description, the longitudinal direction of the base 29 will be referred to as the X-axis direction, the short 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.

[0010] The transport device 20 comprises 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 mounted 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. Furthermore, the X-axis slide mechanism 30 has an electromagnetic motor (see Figure 2) 38, and the X-axis slider 36 moves to any position in the X-axis direction by the drive of the electromagnetic motor 38. The Y-axis slide mechanism 32 includes a Y-axis slide rail 50 and a stage 52. The Y-axis slide rail 50 is mounted on a 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 on the Y-axis slide rail 50 so as to be slidable in the Y-axis direction. Furthermore, the Y-axis sliding mechanism 32 has an electromagnetic motor (see Figure 2) 56, and the stage 52 moves to any position in the Y-axis direction when driven by the electromagnetic motor 56. As a result, the stage 52 moves to any position on the base 29 when driven by the X-axis sliding mechanism 30 and the Y-axis sliding mechanism 32.

[0011] Stage 52 has a base 60, a holding device 62, a lifting device (see FIG. 2) 64, and a heater (see FIG. 2) 66. The base 60 is formed in a flat plate shape, and a substrate is placed on the upper surface. The holding device 62 is provided on both sides of the base 60 in the X-axis direction. Then, both edge portions of the substrate placed on the base 60 in the X-axis direction are sandwiched by the holding device 62, so that the substrate is fixedly held. Further, the lifting device 64 is disposed below the base 60 and raises and lowers the base 60. The heater 66 is built in the base 60 and heats the substrate placed on the base 60 to an arbitrary temperature.

[0012] The first shaping unit 22 is a unit that shapes the wiring of a circuit board, and has a first printing unit 72 and a firing unit 74. The first printing unit 72 has an inkjet head (see FIG. 2) 76, and the inkjet head 76 discharges metal ink linearly. The metal ink is one in which metal nanoparticles of nanometer size, for example, silver fine particles, are dispersed in a solvent. The surface of the metal fine particles is coated with a dispersant to prevent aggregation in the solvent. Further, the inkjet head 76 discharges metal ink from a plurality of nozzles by, for example, a piezo method using a piezoelectric element.

[0013] The firing unit 74 has an infrared irradiation device (see FIG. 2) 78. The infrared irradiation device 78 is a device that irradiates the discharged metal ink with infrared rays. The metal ink irradiated with infrared rays is fired to form wiring. The firing of the metal ink is a phenomenon in which by applying energy, the vaporization of the solvent, the protective film of the metal fine particles, that is, the decomposition of the dispersant, etc. are performed, and the metal fine particles come into contact or fuse, resulting in an increase in conductivity. And when the metal ink is fired, a metal wiring is formed.

[0014] Further, the second shaping unit 23 is a unit for shaping the resin layer of the circuit board, and includes a second printing unit 84 and a curing unit 86. The second printing unit 84 has an inkjet head (see FIG. 2) 88, and the inkjet head 88 discharges an ultraviolet curable resin. The ultraviolet curable resin is a resin that cures upon irradiation with ultraviolet light. Note that the inkjet head 88 may be, for example, a piezo method using a piezoelectric element, or a thermal method that heats the resin to generate bubbles and discharges them from a plurality of nozzles.

[0015] The curing unit 86 includes 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 curable resin discharged by the inkjet head 88. For example, while leveling the surface of the ultraviolet curable resin, the excess resin is scraped off by a roller or a blade to make the thickness of the ultraviolet curable resin uniform. The irradiation device 92 includes a mercury lamp or an LED as a light source, and irradiates the discharged ultraviolet curable resin with ultraviolet light. Thereby, the discharged ultraviolet curable resin cures, and a resin layer is formed.

[0016] The third shaping unit 24 is a unit for shaping the connection portion between the electrodes and wirings of the electronic components on the circuit board, and has a third printing unit 100. The third printing unit 100 has a dispenser (see FIG. 2) 106, and the dispenser 106 discharges a conductive paste. The conductive paste is a resin that cures by heating at a relatively low temperature, in which metal particles of micrometer size are dispersed. Incidentally, the metal particles are in the form of flakes, and the viscosity of the conductive paste is relatively high compared to metal ink. The discharge amount of the conductive paste by the dispenser 106 is controlled by the inner diameter of the needle, the pressure at the time of discharge, and the discharge time.

[0017] Then, the conductive paste discharged by the dispenser 106 is heated by a heater 66 built in the base 60. In the heated conductive paste, the resin cures. In this process, the conductive paste hardens and shrinks, causing the flake-shaped metal particles dispersed within the resin to come into contact with it. This is how the conductive paste exhibits conductivity. Furthermore, the resin in the conductive paste is an organic adhesive, and it exhibits adhesive strength by hardening upon heating.

[0018] The fourth molding unit 25 is a unit that molds resin for fixing electronic components to a circuit board, and has a fourth printing unit 110. The fourth printing unit 110 has a dispenser (see Figure 2) 116, which dispenses thermosetting resin. Thermosetting resin is a resin that hardens when heated. The dispenser 116 is, for example, a piezo type using a piezoelectric element. The thermosetting resin dispensed by the dispenser 116 is heated by a heater 66 built into the base 60 and hardens.

[0019] Furthermore, the pressing unit 26 is a unit for pressing the circuit board and has a pressing section 120. The pressing section 120 has a pressing plate (see Figure 9) 122, a rubber plate (see Figure 9) 124, and a cylinder (see Figure 2) 126. The rubber plate 124 is molded from, for example, silicone rubber and has a plate shape. The pressing plate 122 is molded from, for example, steel and has a plate shape. The rubber plate 124 is attached to the lower surface of the pressing plate 122, and the pressing plate 122 is pressed toward the circuit board by the operation of the cylinder 126. As a result, the circuit board is pressed by the pressing plate 122 via the rubber plate 124. The force pressing the board can be controlled by controlling the operation of the cylinder 126.

[0020] Furthermore, the mounting unit 27 is a unit for mounting electronic components onto a circuit board and has a supply unit 130 and a mounting unit 132. The supply unit 130 has multiple tape feeders (see Figure 2) 134 that feed out taped electronic components one by one, and supplies electronic components at the supply position. Note that the supply unit 130 is not limited to tape feeders 134, but may also be a tray-type supply device that picks up and supplies electronic components from a tray. In addition, the supply unit 130 may be configured to have both tape-type and tray-type supply devices, or other types of supply devices.

[0021] The mounting unit 132 includes a mounting head (see Figure 2) 136 and a moving device (see Figure 2) 138. The mounting head 136 has a suction nozzle (not shown) for adsorbing and holding electronic components. The suction nozzle adsorbs and holds electronic components by air suction when negative pressure is supplied from a positive / negative pressure supply device (not shown). Then, when a small amount of positive pressure is supplied from the positive / negative pressure supply device, the electronic components are released. The moving device 138 moves the mounting head 136 between the supply position of electronic components by the tape feeder 134 and the substrate placed on the base 60. As a result, in the mounting unit 132, electronic components supplied from the tape feeder 134 are held by the suction nozzle, and the electronic components held by the suction nozzle are mounted on the substrate.

[0022] Furthermore, as shown in Figure 2, the control device 28 includes a controller 140 and a plurality of drive circuits 142. The plurality of drive circuits 142 are connected to the electromagnetic motors 38, 56, holding device 62, lifting device 64, heater 66, inkjet head 76, infrared irradiation device 78, inkjet head 88, flattening device 90, irradiation device 92, dispenser 106, dispenser 116, cylinder 126, tape feeder 134, mounting head 136, and moving device 138. The controller 140 is a computer-based device equipped with a CPU, ROM, RAM, etc., and is connected to the plurality of drive circuits 142. As a result, the operation of the transport device 20, first molding unit 22, second molding unit 23, third molding unit 24, fourth molding unit 25, pressing unit 26, and mounting unit 27 is controlled by the controller 1 It is controlled by 40.

[0023] In the circuit forming apparatus 10, a resin laminate is formed on the base 60 using the configuration described above, and wiring is formed on the upper surface of the resin laminate. Then, the electrodes of electronic components are electrically connected to the wiring via conductive paste, and the electronic components are fixed by the resin, thereby forming a circuit board.

[0024] Specifically, first, the stage 52 is moved below the second molding unit 23. Then, in the second molding unit 23, as shown in Figure 3, a resin laminate 152 is formed on the base 60 of the stage 52. The resin laminate 152 is formed by repeatedly ejecting ultraviolet-curable resin from the inkjet head 88 and irradiating the ejected ultraviolet-curable resin with ultraviolet light from the irradiation device 92.

[0025] More specifically, in the second printing section 84 of the second molding unit 23, the inkjet head 88 extrudes a thin film of UV-curable resin onto the upper surface of the base 60. Subsequently, once the UV-curable resin is extruded as a thin film, the UV-curable resin is flattened by the planarizing device 90 in the curing section 86 so that the film thickness of the UV-curable resin becomes uniform. Then, the irradiation device 92 irradiates the thin film of UV-curable resin with ultraviolet light. As a result, a thin film of resin 153 is formed on the base 60.

[0026] Next, the inkjet head 88 ejects a thin film of UV-curable resin onto the thin film resin layer 153. Then, the planarization device 90 flattens the thin film of UV-curable resin, and the irradiation device 92 irradiates the ejected thin film of UV-curable resin with ultraviolet light, thereby laminating another thin film of resin layer 153 on top of the first. In this way, the ejection of UV-curable resin onto the thin film resin layer 153 and the irradiation with ultraviolet light are repeated, and multiple resin layers 153 are laminated to form a resin laminate 152.

[0027] Next, once the resin laminate 152 is formed, the stage 52 is moved below the first molding unit 22. Then, in the first printing section 72 of the first molding unit 22, the inkjet head 76 ejects metallic ink 160 in a linear pattern onto the upper surface of the resin laminate 152, as shown in Figure 4. Subsequently, the infrared irradiation device 78 in the firing section 74 of the first molding unit 22 irradiates the ejected metallic ink 160 with infrared light. This causes the metallic ink 160 to be fired, and wiring 162 is formed on the upper surface of the resin laminate 152. In Figure 4, three wirings 162 are formed, but to distinguish between these three wirings 162, the left wiring in Figure 4 is referred to as wiring 162a, the center wiring as wiring 162b, and the right wiring as wiring 162c.

[0028] Next, once the wiring 162 is formed on the resin laminate 152, it is moved below the second molding unit 23. Then, in the second molding unit 23, the inkjet head 88 extrudes a thin film of UV-curable resin so that the ends of the three wirings 162 are exposed. Subsequently, once the UV-curable resin is extruded in a thin film, the UV-curable resin is flattened in the curing section 86 so that the film thickness of the UV-curable resin becomes uniform. Then, the irradiation device 92 irradiates the thin film of UV-curable resin with ultraviolet light. As a result, a resin layer 156 is formed on the resin laminate 152, as shown in Figure 5.

[0029] Next, the inkjet head 88 ejects a thin film of UV-curable resin only on the upper part of the resin layer 156. In other words, the inkjet head 88 ejects a thin film of UV-curable resin onto the resin layer 156 so that the ends of the three wires 162 are exposed. Then, the planarizing device 90 planarizes the thin film of UV-curable resin, and the irradiation device 92 irradiates the ejected thin film of UV-curable resin with ultraviolet light, thereby forming a layer of UV-curable resin on top of the resin layer 156. Layer 156 is stacked. In this way, the UV-curing resin is repeatedly dispensed onto the resin layer 156 and irradiated with UV light, and multiple resin layers 156 are stacked to form a resin laminate 157. As a result, a resin laminate 157 is formed on top of a resin laminate 152, and the step between the resin laminate 152 and the resin laminate 157 functions as a cavity 154.

[0030] As described above, when the resin laminate 157 is formed on top of the resin laminate 152, the stage 52 is moved below the third molding unit 24. Then, in the third printing section 100 of the third molding unit 24, the dispenser 106 dispenses conductive paste 166 onto both ends of the wiring 162b and onto the ends of the wiring 162a and wiring 162c that are opposite to both ends of the wiring 162b, as shown in Figure 6.

[0031] As described above, when the conductive paste 166 is dispensed onto the end of the wiring 162, the resin laminate 152 is heated by the heater 66 built into the base 60 according to the heating conditions of the conductive paste. This heats the conductive paste 166 through the resin laminate 152, causing it to harden. The heating conditions of the conductive paste are those necessary to completely harden the conductive paste and are set by the manufacturer of the conductive paste. Alternatively, the heating conditions of the conductive paste may be set based on experimental heating results of the conductive paste conducted by the user of the conductive paste. In this way, the conductive paste 166 exhibits conductivity when it is heated according to the heating conditions of the conductive paste and completely hardened.

[0032] As described above, when the conductive paste 166 dispensed at the end of the wiring 162 hardens due to heating, the stage 52 moves below the fourth molding unit 25. Then, in the fourth printing section 110 of the fourth molding unit 25, the dispenser 116 dispenses thermosetting resin 170 onto the upper surface of the resin laminate 152 between the ends of two opposing wirings 162a and b, and then dispenses thermosetting resin 170 onto the upper surface of the resin laminate 152 between the ends of two opposing wirings 162b and c.

[0033] Then, when thermosetting resin 170 is dispensed onto the upper surface of the resin laminate 152 between the ends of two opposing wires 162, the stage 52 is moved below the mounting unit 27. In the mounting unit 27, an electronic component (see Figure 8) 172 is supplied by a tape feeder 134, and the electronic component 172 is held by the suction nozzle of the mounting head 136. The electronic component 172 consists of a component body 176 and two electrodes 178 disposed on the lower surface of the component body 176. The mounting head 136 is then moved by a moving device 138, and the electronic component 172 held by the suction nozzle is mounted on the upper surface of the resin laminate 152, as shown in Figure 8. In Figure 8, two electronic components 172 are mounted on the upper surface of the resin laminate 152, and these two electronic components 172 are of different sizes. For this reason, the smaller electronic component is referred to as electronic component 172a, and the larger electronic component is referred to as electronic component 172b. Then, the two electronic components 172a and 172b are mounted on the upper surface of the resin laminate 152 such that electronic component 172a is electrically connected to two wires 162a and 162b, and electronic component 172b is electrically connected to two wires 162b and 162c.

[0034] Specifically, electronic component 172a is mounted so that its electrode 178 contacts the conductive paste 166 that has hardened on the wiring 162a and b. At this time, the component body 176 of electronic component 172a contacts the thermosetting resin 170 that has been extruded between the wiring 162a and b. Similarly, electronic component 172b is mounted so that its electrode 178 contacts the conductive paste 166 that has hardened on the wiring 162b and c. At this time, the component body 176 of electronic component 172b contacts the thermosetting resin 170 that has been extruded between the wiring 162b and c. In other words, the conductive paste 166 is extruded at the intended mounting position of the electrode 178 on the wiring 162, and the thermosetting resin 170 is extruded at the intended mounting position of the component body 176. Therefore, when electronic component 172 is mounted on the resin laminate 152, the electrode 178 hardens on the wiring 162. The component body 176 comes into contact with the conductive paste 166, and then comes into contact with the thermosetting resin 170. The thermosetting resin 170 that comes into contact with the component body 176 is sealed between the component body 176 and the resin laminate 152. In other words, the thermosetting resin 170 is sealed between the upper surface of the resin laminate 152 and the lower surface of the component body 176. The amount of thermosetting resin 170 dispensed by the dispenser 116 is controlled so that the thermosetting resin 170 does not protrude from between the upper surface of the resin laminate 152 and the lower surface of the component body 176.

[0035] In this way, with the two electronic components 172a and 172b mounted, electronic component 172a is electrically connected to two wires 162a and 162b, and electronic component 172b is electrically connected to two wires 162b and 162c. However, since the electronic component 172 is mounted so that the electrode 178 contacts the hardened conductive paste 166, the contact area between the electrode 178 and the conductive paste 166 is small at this point. On the other hand, the component body 176 of the electronic component 172 contacts the thermosetting resin 170, but since the thermosetting resin 170 is not yet hardened at this point, the contact area between the component body 176 and the thermosetting resin 170 becomes large.

[0036] As described above, when the electronic component 172 is mounted on the upper surface of the resin laminate 152, the stage 52 moves below the pressing unit 26. Then, at the pressing section 120 of the pressing unit 26, as shown in Figure 9, the electronic component 172 mounted on the resin laminate 152 is pressed from above to below by the pressing plate 122 via the rubber plate 124. The outer dimensions of the rubber plate 124 are approximately the same as the outer dimensions of the base 60. Therefore, the entire resin laminate 152 formed on the base 60 is pressed by the rubber plate 124, and the electronic component 172 is pressed toward the resin laminate 152 by the rubber plate 124. In addition, two electronic components 172a and 172b are mounted on the resin laminate 152, and the two electronic components 172 are of different sizes. Therefore, the height dimensions of the two electronic components 172 are different. However, since a rubber plate 124 is attached to the lower surface of the pressing plate 122, the rubber plate 124 elastically deforms when the two electronic components 172 are pressed, allowing the two electronic components 172, which have different heights, to be properly pressed against each other. The thickness of the rubber plate 124 is made larger than the height of the electronic components 172 so that the rubber plate 124 can elastically deform sufficiently when pressing the electronic components 172.

[0037] Furthermore, when the electronic component is pressed by the pressing unit 26, the resin laminate 152 is heated by the heater 66 built into the base 60. As a result, the thermosetting resin 170 is heated and hardened via the resin laminate 152. Here, the heating temperature is, for example, the temperature at which the thermosetting resin 170 hardens (for example, 85°C), and the thermosetting resin 170 hardens by being heated at 85°C for 30 minutes. In other words, the thermosetting resin 170, which is sealed between the upper surface of the resin laminate 152 and the lower surface of the component body 176, hardens while being pressed by the rubber plate 124. As a result, the contact area between the component body 176 and the thermosetting resin 170 becomes even larger, and the adhesive force of the thermosetting resin 170 fixes the electronic component 172 to the upper surface of the resin laminate 152 on the component body 176. Furthermore, when the electronic component 172 is pressed, that is, when the electronic component 172 mounted on the resin laminate 152 is pressed toward the resin laminate 152, the conductive paste 166 in contact with the electrode 178 of the electronic component 172 deforms, increasing the contact area between the electrode 178 and the conductive paste 166. This ensures an electrical connection between the electronic component 172 and the wiring 162.

[0038] Then, once pressing by the pressing unit 26 is complete, the stage 52 is moved below the fourth molding unit 25. Then, in the fourth printing section 110 of the fourth molding unit 25, the dispenser 116 extrudes thermosetting resin 180 around the electronic component 172 so as to cover the sides of the component body 176 of the electronic component 172, as shown in Figure 10. The resin laminate 152 is then heated by the heater 66 built into the base 60. As a result, the thermosetting resin 180 is heated and hardened through the resin laminate 152. Here, the heating temperature is, for example, For example, the temperature at which the thermosetting resin 180 hardens is 85°C, and the thermosetting resin 180 hardens by heating at 85°C for 30 minutes. As a result, the thermosetting resin 180 hardens while covering the sides of the component body 176. In other words, in the case of the electronic component 172 mounted on the resin laminate 152, the thermosetting resins 170 and 180 harden while being sealed between the upper surface of the resin laminate 152 and the lower surface of the component body 176, and covering the sides of the component body 176. As a result, the electronic component 172 mounted on the upper surface of the resin laminate 152 is fixed by the hardened resin.

[0039] In this way, the circuit board 190 is formed when the electronic components 172 mounted on the upper surface of the resin laminate 152 are fixed by the hardened resin. However, when the circuit board 190 is formed, as described above, the resin laminate 152 is heated, the electronic components 172 mounted on the resin laminate 152 are pressed by the rubber plate 124, and the thermosetting resin 170 is sealed beneath the electronic components. For this reason, when the electronic components are pressed by the rubber plate, the thermosetting resin 170 may push the electronic components in the left-right direction. Specifically, as described above, the thermosetting resin 170 hardens when heated, for example, at 85°C for 30 minutes. The thermosetting resin 170 changes from a state of low fluidity to a state of high fluidity as it is heated, and then finally hardens. Therefore, if the thermosetting resin 170 is not sufficiently heated when the electronic component is pressed by the rubber plate, the thermosetting resin 170, which has low fluidity, may be pushed outwards from below the electronic component by the electronic component, causing the electronic component to be pushed outwards from side to side by the thermosetting resin. In such cases, the electronic component mounted on the resin laminate 152 may shift laterally, and the electrodes of the electronic component may separate from the conductive paste 166. In other words, there is a risk that the conductivity between the wiring 162 and the electrodes 178 of the electronic component 172 cannot be properly ensured when the electronic component is pressed by the rubber plate 124.

[0040] Furthermore, when the rubber plate 124 presses against the electronic component 172, the rubber plate 124 expands due to heat, increasing the pressing force of the rubber plate 124 against the electronic component 172. In other words, when the rubber plate 124 is pressing against the electronic component, the rubber plate 124 expands due to heat, increasing the amount of pressure the rubber plate applies to the electronic component by an amount equivalent to the expansion of the rubber plate, thus increasing the pressing force of the rubber plate against the electronic component. As a result, the amount of lateral displacement of the electronic component pressed by the rubber plate increases, and the likelihood of the electrodes of the electronic component separating from the conductive paste 166 increases.

[0041] In light of these considerations, as shown in Figure 11, a generally rectangular tubular sponge 200 is disposed on the lower surface of the rubber plate 124 that presses the electronic components, with the sponge extending downwards. The circumferential dimensions of the sponge 200 are larger than the outer dimensions of the circuit board 190 formed on the upper surface of the base 60, and the height of the sponge 200 is slightly (about 2-3 mm) higher than the height of the circuit board 190. The sponge 200 is a low-elasticity material and is more easily deformed than the rubber plate 124. In other words, the elastic modulus of the sponge 200 is lower than that of the rubber plate 124. Furthermore, the upper end of the sponge 200 is fixed to the lower surface of the rubber plate 124 so that the circuit board 190 formed on the upper surface of the base 60 is located inside the rectangular tubular sponge 200 when viewed from above.

[0042] Then, when the electronic component 172 is pressed by the rubber plate 124, the rubber plate 124 descends, and at this time, as shown in Figure 12, the circuit board 190 enters the interior of the rectangular sponge 200. The descent of the rubber plate 124 stops when the lower end of the sponge 200 contacts the upper surface of the base 60. As a result, before the rubber plate 124 contacts the electronic component 172, that is, before the electronic component 172 is pressed, the space between the rubber plate 124 and the base 60 is surrounded from the side by the sponge 200. At this time, the circuit board 190 is surrounded by the sponge 200, the base 60 and the rubber plate 124. The space is sealed. Also, when the space between the rubber plate 124 and the base 60 is surrounded from the side by the sponge 200, the resin laminate 152 is heated by the heater 66 built into the base 60. In other words, the circuit board 190 is heated while the space between the rubber plate 124 and the base 60 is surrounded from the side by the sponge 200. As a result, the circuit board 190 is heated in a sealed state within the space surrounded by the sponge 200, the base 60 and the rubber plate 124.

[0043] The heating temperature when the circuit board 190 is surrounded from the side by the sponge 200 between the rubber plate 124 and the base 60 is, for example, the temperature at which the thermosetting resin 170 hardens (for example, 85°C). However, the heating time is shorter than the time required for the thermosetting resin 170 to harden (for example, 30 minutes) (for example, 5 minutes). In other words, the specific heating time is set to, for example, 85°C and 5 minutes. When the circuit board 190 is heated at the set temperature for the set time with the rubber plate 124 and the base 60 surrounded from the side by the sponge 200, the thermosetting resin 170 does not harden, but its fluidity increases. Therefore, the fluidity of the thermosetting resin 170 increases before the rubber plate 124 comes into contact with the electronic component 172, that is, before the electronic component is pressed by the rubber plate. Furthermore, before the rubber plate 124 comes into contact with the electronic component 172, the circuit board 190 is heated while the area between the rubber plate 124 and the base 60 is surrounded from the side by the sponge 200, causing the rubber plate to expand due to the heat. Therefore, the rubber plate expands due to the heat before it comes into contact with the electronic component 172, that is, before the electronic component is pressed by the rubber plate.

[0044] Then, after the circuit board 190 is heated with the rubber plate 124 and the base 60 surrounded from the side by the sponge 200, the rubber plate 124 descends as shown in Figure 13, pressing the electronic component 172 against the rubber plate. At this time, the sponge 200 is compressed vertically by elastic deformation as it is sandwiched between the base 60 and the rubber plate 124. The heating temperature when the electronic component is pressed by the rubber plate is the temperature at which the thermosetting resin 170 hardens (for example, 85°C), and the heating time is the time required for the thermosetting resin 170 to harden (for example, 30 minutes). As a result, the thermosetting resin 170 hardens between the resin laminate 152 and the electronic component 172.

[0045] Thus, before the electronic components are pressed by the rubber plate, the circuit board is heated while surrounded from the sides by the sponge 200 between the rubber plate and the base, increasing the fluidity of the thermosetting resin 170 and causing the rubber plate to expand due to heat. Therefore, before the electronic components are pressed by the rubber plate, the highly fluid thermosetting resin 170 spreads out horizontally below the electronic components, making it difficult for the electronic components to be pushed horizontally by the thermosetting resin even when pressed by the rubber plate. In other words, by increasing the fluidity of the thermosetting resin 170 before the electronic components are pressed by the rubber plate, it is possible to suppress the horizontal displacement of the electronic components when they are pressed by the rubber plate. Furthermore, since the rubber plate has already expanded due to heat before the electronic components are pressed by the rubber plate, it does not expand further while the rubber plate is pressing on the electronic components. Therefore, the pressing force on the electronic components by the rubber plate is smaller compared to when the rubber plate expands due to heat while pressing on the electronic components. In other words, by allowing the rubber plate to expand due to heat before the electronic component is pressed by the rubber plate, it is possible to suppress the amount of lateral displacement of the electronic component when pressed by the rubber plate. This makes it possible to properly ensure the conductivity between the wiring 162 and the electrode 178 of the electronic component 172 during the pressing operation of the electronic component by the rubber plate.

[0046] Furthermore, as shown in Figure 2, the controller 140 of the control device 28 has a coating section 210, a mounting section 212, a heating section 214, and a pressing section 216. The coating section 210 is a functional section for coating the thermosetting resin 170 so that it comes into contact with the component body 176 of the electronic component 172. The mounting section 212 is a functional section for mounting the electronic component 172 so that the electrode 178 comes into contact with the conductive paste 166 and the component body 176 comes into contact with the thermosetting resin 170. The heating section 214 is a functional section for heating the circuit board 190 while the space between the rubber plate 124 and the base 60 is surrounded from the side of the circuit board 190 by a sponge 200. The pressing section 216 is a functional section for pressing the rubber plate 124 toward the resin laminate 152 while heating the circuit board 190, with the space between the rubber plate 124 and the base 60 surrounded from the side of the circuit board 190 by the sponge 200.

[0047] Furthermore, in the first embodiment described above, the conductivity between the wiring 162 and the electronic component 172 is ensured by heating the circuit board while the space between the rubber plate and the base is surrounded from the side by the sponge 200 before the electronic component is pressed by the rubber plate. On the other hand, in the second embodiment, the conductivity between the wiring 162 and the electronic component 172 can also be ensured by using a pressing body for pressing the electronic component that is made up of multiple laminated members with different coefficients of thermal expansion.

[0048] Specifically, as shown in Figure 14, a pressing body 220, which is made up of multiple laminated members with different coefficients of thermal expansion, is disposed on the lower surface of the pressing plate 122. The pressing body 220 is composed of a first rubber plate 230, double-sided tape 232, and a second rubber plate 234. The first rubber plate 230 is made of the same material as the rubber plate 124 in the above embodiment, and the outer dimensions of the first rubber plate 230 are similar to those of the rubber plate 124, and are about the same as those of the base 60. Also, the thickness dimension of the first rubber plate 230 is similar to that of the rubber plate 124, and is greater than the height dimension of the electronic component so that the first rubber plate 230 can elastically deform sufficiently when pressing the electronic component. For example, the thickness dimension of the first rubber plate 230 is 5 to 10 mm.

[0049] A double-sided tape 232, with dimensions identical to the outer dimensions of the first rubber plate 230, is attached to the upper surface of the first rubber plate 230. The thickness of the double-sided tape 232 is, for example, about 0.025 mm. The material of the double-sided tape 232 is polyimide, and the coefficient of linear expansion of polyimide is 1.5. On the other hand, the coefficient of linear expansion of the first rubber plate 230 is 40 to 50. Thus, the coefficient of linear expansion of the double-sided tape 232 is smaller than that of the first rubber plate 230. The coefficient of linear expansion indicates the rate at which the length or volume of an object expands per unit of temperature due to a rise in temperature, and its unit is 10⁻⁵ / K. Therefore, the larger the value of the coefficient of linear expansion, the more easily the material expands due to a rise in temperature. In other words, the double-sided tape 232, which does not expand easily due to a rise in temperature, is attached to the upper surface of the first rubber plate 230, which expands easily due to a rise in temperature.

[0050] Furthermore, a second rubber plate 234 is attached to the upper surface of the double-sided tape 232. The outer dimensions of the second rubber plate 234 are the same as those of the first rubber plate 230 and the double-sided tape 232. The thickness of the second rubber plate 234 is such that it can absorb the impact of deformation when the first rubber plate 230 deforms by pressing on an electronic component (for example, 5 mm). Since the second rubber plate 234 is made of the same material as the first rubber plate 230, the coefficient of linear expansion of the second rubber plate 234 is also 40 to 50. In other words, in the pressing body 220, the double-sided tape 232, which is less likely to expand due to temperature rise, is sandwiched between the first rubber plate 230 and the second rubber plate 234, which are more likely to expand due to temperature rise. By using such a pressing body 220 to press the electronic components 172 on the circuit board 190, deformation of the pressing body 220 due to thermal expansion caused by heating can be suppressed, and displacement of the electronic components 172 caused by the thermal expansion of the pressing body 220 can be suppressed. In other words, the first rubber plate 230 and the second rubber plate 23 When 4 expands due to heat, the double-sided tape 232 sandwiched between the first rubber plate 230 and the second rubber plate 234 is less susceptible to thermal expansion, thus restricting the thermal expansion of the first rubber plate 230 and the second rubber plate 234. As a result, when pressing an electronic component in a heated state, deformation of the pressing body 220 due to thermal expansion is suppressed, and displacement of the electronic component 172 caused by the thermal expansion of the pressing body 220 is suppressed. This makes it possible to ensure conductivity between the wiring 162 and the electronic component 172.

[0051] Furthermore, because the double-sided tape 232 sandwiched between the first rubber plate 230 and the second rubber plate 234 is thin, it deforms appropriately together with the first rubber plate 230 when electronic components are pressed. In other words, when electronic components are pressed, the first rubber plate 230 deforms in accordance with differences in the dimensions of the electronic components, and the double-sided tape 232 follows the first rubber plate 230 and deforms appropriately. This makes it possible to properly press the electronic components.

[0052] Furthermore, in the third embodiment, the conductivity between the wiring 162 and the electronic component 172 is ensured by using a pressing body made of two rubber plates with different coefficients of thermal expansion stacked together as the pressing body for pressing the electronic component. Specifically, as shown in Figure 15, a pressing body 254 is provided on the lower surface of the pressing plate 122, which is made up of a first rubber plate 250 and a second rubber plate 252 stacked together and having different coefficients of thermal expansion. The first rubber plate 250 is the same as the first rubber plate 230 in the second embodiment. That is, for example, the outer dimensions of the first rubber plate 250 are about the same as the outer dimensions of the base 60, and the thickness of the first rubber plate 250 is 5 to 10 mm. Also, the coefficient of thermal expansion of the first rubber plate 250 is, for example, 40 to 50.

[0053] A second rubber plate 252, having the same external dimensions as the first rubber plate 250, is attached to the upper surface of the first rubber plate 250. The thickness of the second rubber plate 252 is, for example, 5 mm. The second rubber plate 252 is made of a different material than the first rubber plate 250, and its coefficient of linear expansion is, for example, 20 to 25. In other words, in the pressing body 254, the second rubber plate 252, which is less prone to expansion due to temperature rise, is attached to the upper surface of the first rubber plate 250, which is more prone to expansion due to temperature rise. By pressing the electronic components 172 of the circuit board 190 using such a pressing body 254, deformation of the pressing body 254 due to thermal expansion caused by heating is suppressed, and displacement of the electronic components 172 caused by the thermal expansion of the pressing body 254 is suppressed. In other words, when the first rubber plate 250 expands due to heat, the second rubber plate 252, which is attached to the upper surface of the first rubber plate 250, expands less easily, thus the thermal expansion of the first rubber plate 250 is restrained by the second rubber plate 252. As a result, when pressing an electronic component in a heated state, deformation of the pressing body 254 due to thermal expansion is suppressed, and displacement of the electronic component 172 caused by the thermal expansion of the pressing body 254 is suppressed. This makes it possible to ensure conductivity between the wiring 162 and the electronic component 172.

[0054] In the above embodiment, the circuit forming apparatus 10 is an example of an electrical circuit forming apparatus. The fourth molding unit 25 is an example of a coating apparatus. The pressing unit 26 is an example of a pressing apparatus. The mounting unit 27 is an example of a mounting apparatus. The base 60 is an example of a base. The rubber plate 124 is an example of a pressing body. The resin laminate 152 is an example of a resin layer. The wiring 162 is an example of metal wiring. The thermosetting resin 170 is an example of a curable resin. The electronic component 172 is an example of an electronic component. The component body 176 is an example of a component body. The pressing body 220 is an example of a pressing body. The first rubber plate 230 is an example of a first elastic member. The double-sided tape 232 is an example of a low coefficient of thermal expansion member. The second rubber plate 234 is an example of a second elastic member. The first rubber plate 250 is an example of a first elastic member. The second rubber plate 252 is an example of a low coefficient of thermal expansion member. The pressing body 254 is an example of a pressing body. The process performed by the coating unit 210 is an example of a coating process. The process performed by the mounting unit 212 is an example of a mounting process. The process performed by the pressing unit 216 is an example of a heating process.

[0055] It should be noted that the present invention is not limited to the above embodiments, and can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. For example, in the first embodiment described above, the circuit board is heated while the space between the rubber plate and the base is surrounded from the sides by the sponge 200 before the electronic components on the circuit board are pressed. In other words, after a heating step in which the circuit board is heated while the space between the rubber plate and the base is surrounded from the sides by the sponge 200, a pressing step is performed in which the electronic components are pressed while the circuit board is heated while the space between the rubber plate and the base is surrounded from the sides by the sponge 200. On the other hand, even if the heating step is not performed, and the pressing step is performed in which the electronic components are pressed while the circuit board is heated while the space between the rubber plate and the base is surrounded from the sides by the sponge 200, the conductivity between the wiring 162 and the electronic components 172 can still be ensured. In other words, even if the pressing process is performed without a heating process, the circuit board is efficiently heated in a sealed space during the pressing process, which allows the fluidity of the thermosetting resin 170 to be rapidly increased when the electronic components are pressed. This makes it possible to suppress the lateral displacement of the electronic components when they are pressed by the rubber plate, and ensures the conductivity between the wiring 162 and the electronic components 172.

[0056] Furthermore, in the first embodiment described above, a heating process is performed for a set time (for example, 5 minutes) in which the circuit board is heated while the space between the rubber plate and the base is surrounded from the side by the sponge 200. Alternatively, the heating process may be performed until the temperature difference between the rubber plate 124 and the resin laminate 152 falls below a set temperature (for example, 1°C). In this way, by performing the heating process until the temperature difference between the rubber plate 124 and the resin laminate 152 falls below a set temperature, the rubber plate 124 and the resin laminate 152 are sufficiently heated. This makes it possible to increase the fluidity of the thermosetting resin 170 and to allow the rubber plate 124 to expand due to heat during the heating process, thereby ensuring conductivity between the wiring 162 and the electronic components 172.

[0057] Furthermore, in the first embodiment described above, the rubber plate 124 descends until the lower end of the sponge 200 contacts the upper surface of the base 60 during the heating process. However, the descent of the rubber plate 124 may stop before the lower end of the sponge 200 contacts the upper surface of the base 60. In other words, the rubber plate 124 only needs to descend to the extent that the space between the rubber plate and the base is surrounded by the sponge 200 from the side of the circuit board.

[0058] Furthermore, although a rubber plate 124 is used in the first embodiment described above, it is possible to use the pressing body 220 of the second embodiment or the pressing body 254 of the third embodiment in the first embodiment. This makes it possible to more preferably ensure conductivity between the wiring 162 and the electronic component 172.

[0059] Furthermore, in the first embodiment described above, the electronic component 172 is pressed toward the resin laminate 152 by the rubber plate 124 as it descends. However, the electronic component 172 may be pressed toward the resin laminate 152 by the rubber plate 124 as the stage 52 rises. Alternatively, the electronic component 172 may be pressed toward the resin laminate 152 by the rubber plate 124 as the rubber plate 124 descends and the stage 52 rises.

[0060] Furthermore, in the first embodiment described above, the thermosetting resin 170 is dispensed at the intended mounting position of the component body 176 of the electronic component 172 before the electronic component 172 is mounted on the resin laminate 152, but after the electronic component 172 is mounted on the resin laminate 152 the thermosetting resin 170 is dispensed at the resin laminate The thermosetting resin 170 may be discharged onto the body 152. In this case, the thermosetting resin 170 is discharged between the lower surface of the component body 176 of the electronic component 172 mounted on the resin laminate 152 and the upper surface of the resin laminate 152. After the thermosetting resin 170 has been discharged between the lower surface of the component body 176 of the electronic component 172 and the upper surface of the resin laminate 152, the electronic component 172 is pressed by the rubber plate 124 in the pressing unit 26.

[0061] Furthermore, in the above embodiment, the electronic component 172 is mounted when the conductive paste 166 is fully cured, and the electronic component 172 is pressed by the rubber plate 124. Alternatively, the electronic component 172 may be mounted when the conductive paste 166 is semi-cured, and the electronic component 172 may be pressed by the rubber plate 124. Also, the electronic component 172 may be mounted when the conductive paste 166 is neither semi-cured nor fully cured, and the electronic component 172 may be pressed by the rubber plate 124. Note that when the electronic component 172 is mounted when the conductive paste 166 is semi-cured or neither semi-cured nor fully cured, and the electronic component 172 is pressed by the rubber plate 124, the conductive paste is fully cured by heating with the heater 66.

[0062] Furthermore, in the above embodiment, a thermosetting resin is used as the thermosetting resin 170 for fixing the electronic component 172 to the resin laminate 152, but it is possible to form ultraviolet curing resins, two-component curing resins, thermoplastic resins, etc. Also, in the above embodiment, an ultraviolet curing resin is used as the resin for forming the resin laminate 152, and a thermosetting resin is used as the resin for fixing the electronic component 172. In other words, the resin for forming the resin laminate 152 and the resin for fixing the electronic component 172 are different curing resins, but the resin for forming the resin laminate 152 and the resin for fixing the electronic component 172 may be the same curing resin. [Explanation of Symbols]

[0063] 10: Circuit forming apparatus (electrical circuit forming apparatus) 25: 4th molding unit (coating apparatus) 26: Pressing unit (pressing device) 27: Mounting unit (mounting device) 60: Base 124: Rubber plate (pressing body) 152: Resin laminate (resin layer) 162: Wiring (metal wiring) 170: Thermosetting resin (curable resin) 172: Electronic component 176: Component body 220: Pressing body (pressing body) 230: First rubber plate (first elastic member) 232: Double-sided tape (low coefficient of linear expansion member) 234: Second rubber plate (second elastic member) 250: First rubber plate (first elastic member) 252: Second rubber plate (low coefficient of linear expansion member) 210: Coating section (coating process) 212: Mounting section (mounting process) 214: Heating section (heating process) 216: Pressing section (pressing process)

Claims

[Claim 1] A resin layer is placed on a base, and an mounting process is performed in which electronic components are mounted so as to be electrically connected to metal wiring formed on the resin layer. A coating step of applying a curable resin onto the resin layer so as to come into contact with the component body of the electronic component, A pressing step in which the electronic component mounted in the mounting step is pressed relative to the resin layer with a pressing body, Includes, The pressing step is, With the base and the pressing body surrounding the resin layer from the side, the curable resin is heated while the electronic component is pressed relative to it by the pressing body. Prior to the pressing step, the process further includes a heating step in which the curable resin is heated while the resin layer is surrounded from the side between the base and the pressing body. The aforementioned heating step is An electrical circuit formation method comprising heating the curable resin while surrounding the base and the pressing body from the side of the resin layer until the temperature difference between the pressing body and the resin layer becomes less than or equal to a set temperature difference.

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