Circuit formation method and circuit formation device

Abstract

A circuit formation method according to the present disclosure comprises: a wiring formation step for forming wiring on the upper surface of a first resin layer by using a metal-containing liquid; a mounting step for mounting an electronic component on the upper surface of the first resin layer so that electrodes of the electronic component are in contact with the wiring; and a resin layer formation step for forming a second resin layer that covers the wiring by discharging a curable resin onto the upper surface of the first resin layer excluding the electronic component to form and laminate a layer of the curable resin, after the electronic component is mounted on the upper surface of the first resin layer.

Description

Circuit forming method and circuit forming device

[0001] The present invention relates to a circuit forming method and a circuit forming apparatus for mounting electronic components so that their electrodes come into contact with wiring formed on the upper surface of a resin layer.

[0002] Japanese Patent Application Laid-Open No. 2003-144992 discloses a technique for mounting electronic components so that their electrodes come into contact with wiring formed on the upper surface of a resin layer.

[0003] JP 2022-112234 Public Relations

[0004] The present invention addresses the problem of appropriately ensuring electrical continuity between wiring and electrodes in an electronic component mounted so that electrodes come into contact with wiring formed on the upper surface of a resin layer.

[0005] In order to solve the above problems, this specification discloses a circuit formation method including: a wiring formation step of forming wiring on the upper surface of a first resin layer using a metal-containing liquid; a mounting step of mounting an electronic component on the upper surface of the first resin layer so that electrodes of the electronic component contact the wiring; and a resin layer formation step of, after the electronic component has been mounted on the upper surface of the first resin layer, ejecting a curable resin onto the upper surface of the first resin layer excluding the electronic component to form and stack a layer of the curable resin, thereby forming a second resin layer that covers the wiring.

[0006] The present specification also discloses a circuit forming apparatus including a metal-containing liquid discharging device that discharges a metal-containing liquid, a mounting device that performs mounting work of electronic components, a resin discharging device that discharges a curable resin, and a control device, wherein the control device performs the following operations: a wiring forming process in which wiring is formed by discharging the metal-containing liquid onto an upper surface of a first resin layer using the metal-containing liquid discharging device; a mounting process in which the mounting device mounts the electronic component on the upper surface of the first resin layer so that electrodes of the electronic component contact the wiring; and a resin layer forming process in which, after the electronic component has been mounted on the upper surface of the first resin layer, the resin discharging device discharges the curable resin onto the upper surface of the first resin layer excluding the electronic component to form and stack layers of the curable resin, thereby forming a second resin layer that covers the wiring.

[0007] In the present disclosure, electronic components are mounted on the top surface of the first resin layer so that the electrodes contact the wiring formed on the top surface of the first resin layer, and then a curable resin is ejected onto the top surface of the first resin layer other than the electronic components to form a curable resin layer and stack them to form a second resin layer covering the wiring. In other words, the electronic components are mounted on the top surface of the first resin layer before the second resin layer is formed on the top surface of the first resin layer. This makes it possible to mount the electronic components on the first resin layer without any influence during the formation of the second resin layer, and ensures appropriate conduction between the wiring and the electrodes.

[0008] 1 is a diagram showing an example of a circuit forming apparatus; FIG. 2 is a block diagram showing an example of a control apparatus; FIG. 3 is a cross-sectional view showing an example of a circuit board in a state where a resin laminate has been formed; FIG. 4 is a cross-sectional view showing an example of a circuit board in a state where wiring has been formed on the resin laminate; FIG. 5 is a cross-sectional view showing an example of a circuit board in a state where a second-layer resin laminate has been further formed on the resin laminate; FIG. 6 is a cross-sectional view showing an example of a circuit board in a state where bumps have been formed on wiring; FIG. 7 is a cross-sectional view showing an example of a circuit board in a state where conductive paste has been dispensed on the bumps; FIG. 8 is a cross-sectional view showing an example of a circuit board in a state where thermosetting resin has been dispensed on the resin laminate; FIG. 9 is a cross-sectional view showing an example of a circuit board in a state where electronic components have been mounted; FIG. 10 is a cross-sectional view showing an example of a circuit board in a state where electronic components have been pressed against the resin laminate; FIG. 11 is a cross-sectional view showing an example of a circuit board in a state where thermosetting resin has been dispensed into the cavity; FIG. 12 is a cross-sectional view showing an example of a circuit board in a state where bumps have been formed on wiring before a second-layer resin laminate is formed; FIG. 13 is a cross-sectional view showing an example of a circuit board in a state where conductive paste has been dispensed on the bumps before a second-layer resin laminate is formed; FIG. 14 is a cross-sectional view showing an example of a circuit board in a state where thermosetting resin has been dispensed on the resin laminate before a second-layer resin laminate is formed. FIG. 1 is a cross-sectional view showing an example of a circuit board on which an electronic component is mounted before a second-layer resin laminate is formed. FIG. 2 is a cross-sectional view showing an example of a circuit board on which an electronic component is pressed against a resin laminate. FIG. 3 is a cross-sectional view showing an example of a circuit board on which a second-layer resin laminate is further formed on a resin laminate so as to surround an electronic component mounted on the upper surface of the resin laminate with a small gap. FIG. 4 is a cross-sectional view showing an example of a circuit board on which an electronic component is pressed against a resin laminate. FIG. 5 is a cross-sectional view showing an example of a circuit board on which a second-layer resin laminate is further formed on a resin laminate so as to surround an electronic component mounted on the upper surface of the resin laminate with a small gap. FIG. 6 is a cross-sectional view showing an example of a circuit board on which a second-layer resin laminate is further formed on a resin laminate so as to surround an electronic component mounted on the upper surface of the resin laminate with a predetermined gap. FIG. 7 is a cross-sectional view showing an example of a circuit board on which a thermosetting resin is dispensed between the second-layer resin laminate and the electronic component.

[0009] 1 shows an example of a circuit forming apparatus 10. The circuit forming apparatus 10 includes a conveying device 20, a first modeling unit 22, a second modeling unit 23, a third modeling unit 24, a fourth modeling unit 25, a pressing 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 23, the third modeling unit 24, the fourth modeling unit 25, the pressing 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.

[0010] 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 the 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, which is driven to move the X-axis slider 36 to any position in the X-axis direction. 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. A 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 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.

[0011] The stage 52 has a base 60, a holding device 62, an elevating 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 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 placed on the base 60 in the X-axis direction, thereby fixedly holding the substrate. The elevating device 64 is disposed below the base 60 and raises and lowers the base 60. The heater 66 is built into the base 60 and heats the substrate placed on the base 60 to a desired temperature.

[0012] The first modeling unit 22 is a unit that models the wiring of a circuit board and includes a first printing unit 72 and a baking unit 74. The first printing unit 72 includes an inkjet head 76 (see FIG. 2 ) that ejects metal ink in a linear pattern. The metal ink is a dispersion of fine particles (e.g., nanometer-sized metal fine particles) of a metal (e.g., silver) in a solvent. The surfaces of the metal fine 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.

[0013] 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. The metal ink irradiated with infrared rays is baked, forming 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.

[0014] The second modeling unit 23 is a unit that models the resin layer of the circuit board, and includes a second printing unit 84 and a curing unit 86. The second printing unit 84 includes an inkjet head 88 (see FIG. 2 ) 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 inkjet head using a piezoelectric element, or a thermal-type inkjet head that heats the resin to generate bubbles and ejects the resin from multiple nozzles.

[0015] The curing unit 86 has an irradiation device (see FIG. 2) 92. The irradiation device 92 has a mercury lamp or an LED as a light source, and irradiates the discharged ultraviolet curable resin with ultraviolet light. This cures the discharged ultraviolet curable resin, forming a resin layer.

[0016] The third modeling unit 24 is a unit that models connection portions between electrodes and wiring of electronic components on a circuit board, and includes a first dispensing unit 100. The first dispensing unit 100 includes a dispenser 106 (see FIG. 2 ), which dispenses conductive paste. The conductive paste is made by dispersing metal particles in a resin that hardens when heated at a relatively low temperature. The metal particles in the conductive paste are smaller than the metal microparticles in metal ink. The conductive paste contains, for example, micrometer-sized metal particles. The metal particles are flake-shaped, and the viscosity of the conductive paste is relatively high compared to that of metal ink.

[0017] The conductive paste dispensed by the dispenser 106 is then heated by the heater 66 built into the base 60. The resin in the heated conductive paste hardens. At this time, the resin in the conductive 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 paste to exhibit conductivity. The resin in the conductive paste is an organic adhesive, and exhibits adhesive strength when hardened by heating.

[0018] The fourth modeling unit 25 is a unit that models resin for fixing electronic components to a circuit board, and includes a second dispensing unit 110. The second dispensing unit 110 includes a dispenser 116 (see FIG. 2 ), which dispenses thermosetting resin. Thermosetting resin is a resin that hardens when heated. The dispenser 116 is, for example, an air pulse type that uses compressed air. The thermosetting resin dispensed by the dispenser 116 is heated by a heater 66 built into the base 60 and hardens.

[0019] The pressing unit 26 is a unit for pressing the circuit board and includes a pressing section 120. The pressing section 120 includes a pressing plate (see FIG. 10) 122, a rubber plate (see FIG. 10) 124, and a cylinder (see FIG. 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 underside of the pressing plate 122. By operating the cylinder 126, the pressing plate 122 is pressed relatively toward the circuit board. As a result, the circuit board is pressed by the pressing plate 122 via the rubber plate 124. By controlling the operation of the cylinder 126, the force pressing the board can be controllably changed. The base 60 held by the holding device 62 may be raised by the lifting device 64, thereby pressing the pressing plate 122 relatively against the circuit board placed on the base 60. Alternatively, the cylinder 126 may be actuated to press the pressing plate 122 against the circuit board, and the base 60 held by the holding device 62 may be raised by the lifting device 64, thereby pressing the pressing plate 122 relatively against the circuit board placed on the base 60.

[0020] The mounting unit 27 is a unit that mounts electronic components on a circuit board and includes a supply unit 130 and a mounting unit 132. The supply unit 130 includes, for example, a plurality of tape feeders 134 (see FIG. 2 ) that feed taped electronic components one by one, and supplies the electronic components at a supply position. Note that the supply unit 130 is not limited to the tape feeders 134, and may also be a tray-type supply device that picks up and supplies electronic components from a tray. The supply unit 130 may also be configured to include both tape-type and tray-type supply devices, or other types of supply devices.

[0021] The mounting unit 132 has a mounting head 136 (see FIG. 2) and a moving device 138 (see FIG. 2). The mounting head 136 has a suction nozzle (not shown) for suctioning and holding electronic components. The suction nozzle sucks and holds electronic components by air when negative pressure is supplied from a positive / negative pressure supply device (not shown). The positive / negative pressure supply device then supplies a slight positive pressure to the suction nozzle, which then releases the electronic component. The moving device 138 also moves the mounting head 136 between the position where electronic components are supplied by the tape feeder 134 and the circuit board 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 onto the circuit board.

[0022] 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, the holding device 62, the lifting device 64, the heater 66, the inkjet head 76, the infrared irradiation device 78, the inkjet head 88, the irradiation device 92, the dispensers 106, 116, the cylinder 126, the tape feeder 134, the mounting head 136, and the moving device 138. The controller 140 includes a CPU, ROM, RAM, etc., and is primarily a computer, and is connected to the plurality of drive circuits 142. As a result, the controller 140 controls the operations of the transport device 20, the first modeling unit 22, the second modeling unit 23, the third modeling unit 24, the fourth modeling unit 25, the pressing unit 26, and the mounting unit 27.

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

[0024] An example of a process for forming a circuit board will be described. Specifically, first, the stage 52 is moved to below the second modeling unit 23. Then, in the second modeling unit 23, a resin laminate 152 is formed on the base 60 of the stage 52, as shown in FIG. 3 . The resin laminate 152 is formed by repeatedly discharging an ultraviolet curable resin from the inkjet head 88 and irradiating the discharged ultraviolet curable resin with ultraviolet light by the irradiation device 92.

[0025] More specifically, in the second printing unit 84 of the second modeling unit 23, the inkjet head 88 ejects a thin film of ultraviolet curable resin onto the upper surface of the base 60. Then, after the ultraviolet curable resin has been ejected in the form of a thin film, the irradiation device 92 in the curing unit 86 irradiates the thin film of ultraviolet curable resin with ultraviolet light. As a result, a resin layer 153 is formed on the base 60.

[0026] Next, the inkjet head 88 ejects a thin film of ultraviolet curable resin onto the resin layer 153. Then, the irradiation device 92 irradiates the ultraviolet curable resin ejected in the thin film with ultraviolet light, thereby laminating resin layers 153 on top of each other. In this manner, the ejection of ultraviolet curable resin onto the resin layer 153 and the irradiation of ultraviolet light are repeated, and a plurality of resin layers 153 are laminated, thereby forming a resin laminate 152.

[0027] Next, once the resin laminate 152 is formed, the stage 52 is moved 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 160 in a line shape according to the circuit pattern onto the upper surface of the resin laminate 152, as shown in FIG. 4 . Subsequently, in the baking unit 74 of the first modeling unit 22, the infrared irradiation device 78 irradiates infrared rays onto the metal ink 160 ejected according to the circuit pattern. As a result, the metal ink 160 is baked, and wiring 162 is formed on the upper surface of the resin laminate 152.

[0028] Next, when the wiring 162 is formed on the resin laminate 152, the stage 52 is moved below the second modeling unit 23. Then, in the second modeling unit 23, the inkjet head 88 ejects the ultraviolet curing resin in the form of a thin film so that the ends of the wiring 162 are exposed. Next, when the ultraviolet curing resin has been ejected in the form of a thin film, the irradiation device 92 in the curing section 86 irradiates the thin film of ultraviolet curing resin with ultraviolet rays. As a result, a resin layer 156 is formed on the resin laminate 152, as shown in FIG. 5 .

[0029] Next, the inkjet head 88 ejects a thin film of ultraviolet curable resin only onto the resin layer 156. That is, the inkjet head 88 ejects the ultraviolet curable resin onto the resin layer 156 so that the ends of the wiring 162 are exposed. The irradiation device 92 then irradiates the ejected thin film of ultraviolet curable resin with ultraviolet light, thereby laminating the resin layer 156 on top of the resin layer 156. In this manner, the ejection of ultraviolet curable resin onto the resin layer 156 and the irradiation of ultraviolet light are repeated, laminating multiple resin layers 156, thereby forming a resin laminate 157. As a result, the resin laminate 157 is formed on the resin laminate 152, and the step between the resin laminate 152 and the resin laminate 157 functions as the cavity 154. Note that the ends of the wiring 162 are exposed inside the cavity 154 of the resin laminate 157, and the portions of the wiring 162 other than the ends are covered by the resin laminate 157. Therefore, the resin laminate 157 functions as a resist layer.

[0030] Once the resin laminate 157 functioning as a resist layer is formed on the resin laminate 152 in this manner, the stage 52 is moved below the third modeling unit 24. Then, in the first dispensing unit 100 of the third modeling unit 24, the dispenser 106 dispenses conductive paste 166 onto the end of the wiring 162, as shown in FIG. 6 . Once the conductive paste 166 has been dispensed onto the end of the wiring 162 in this manner, the heater 66 built into the base 60 heats the resin laminate 152. At this time, the conductive paste 166 is heated via the resin laminate 152 and hardens. This causes the conductive paste 166 to exhibit conductivity. Note that the hardened conductive paste 166 functions as a bump (a connection portion between the wiring and the electrode), and therefore the hardened conductive paste 166 is referred to as a bump 168.

[0031] 7, the dispenser 106 in the first dispensing section 100 of the third modeling unit 24 dispenses the conductive paste 170 onto the bumps 168. Note that at the timing when the conductive paste 170 is dispensed onto the bumps 168, the conductive paste 170 is not heated and has not yet hardened.

[0032] Next, the stage 52 is moved to below the fourth modeling unit 25. Then, in the second dispensing unit 110 of the fourth modeling unit 25, the dispenser 116 dispenses the thermosetting resin 171 onto the upper surface of the resin laminate 152 between the wirings 162, as shown in FIG.

[0033] Then, once the thermosetting resin 171 has been dispensed onto the upper surface of the resin laminate 152 between the ends of the wiring 162, the stage 52 is moved below the mounting unit 27. In the mounting unit 27, an electronic component 172 (see FIG. 9 ) is supplied by the tape feeder 134, and the electronic component 172 is held by the suction nozzle of the mounting head 136. The electronic component 172 is composed of a component body 176 and a plurality of (e.g., two) electrodes 178 disposed on the underside of the component body 176. The mounting head 136 is then moved by the moving device 138, and the electronic component 172 held by the suction nozzle is mounted inside the cavity 154 so as to be electrically connected to the wiring 162, as shown in FIG. 9 . Specifically, the electronic component 172 is mounted so that the electrodes 178 of the electronic component 172 contact the conductive paste 170 dispensed onto the bumps 168 formed on the wiring 162. At this time, the component body 176 of the electronic component 172 comes into contact with the thermosetting resin 171 dispensed between the wiring 162. That is, the conductive paste 166 and the conductive paste 170 are dispensed at the intended mounting positions of the electrodes 178 on the wiring 162, and the thermosetting resin 171 is dispensed at the intended mounting position of the component body 176. Therefore, when the electronic component 172 is mounted, the electrodes 178 come into contact with the conductive paste 170 dispensed onto the bumps 168 formed on the wiring 162, and the component body 176 comes into contact with the thermosetting resin 171. The thermosetting resin 171 in contact with the component body 176 is then sealed between the component body 176 and the resin laminate 152. That is, the thermosetting resin 171 is sealed between the upper surface of the resin laminate 152 and the lower surface of the component body 176. The electrodes 178 are also in close contact with the uncured conductive paste 170.

[0034] Once the electronic component 172 is mounted in this manner, the stage 52 is moved below the pressing unit 26. Then, in the pressing portion 120 of the pressing unit 26, the electronic component 172 is pressed from above downward by the pressing plate 122 via the rubber plate 124, as shown in FIG. 10 . While the electronic component 172 is being pressed by the pressing unit 26, the heater 66 built into the base 60 heats the resin laminate 152. This heats and hardens the conductive paste 170 and thermosetting resin 171 via the resin laminate 152. At this time, the hardened conductive paste 170 exhibits conductivity and functions as a bump. The bumps 168 formed by hardening the conductive paste 166 and the bumps formed by hardening the conductive paste 170 are collectively referred to as bumps 180. In this way, when electronic component 172 is pressed by pressing plate 122, component body 176 and thermosetting resin 171 come into close contact with each other, and electrodes 178 and bumps 180 come into close contact with each other. As a result, electronic component 172 is fixed to the upper surface of resin laminate 152 in component body 176 by the adhesive force of thermosetting resin 171, and electrical connection between electronic component 172 and wiring 162 is ensured by the adhesive force between electrodes 178 and bumps 180.

[0035] Then, when the pressing unit 26 completes pressing, the stage 52 is moved below the fourth modeling unit 25. Then, in the second dispensing section 110 of the fourth modeling unit 25, the dispenser 116 dispenses the thermosetting resin 182 between the side surface of the component body 176 of the electronic component 172 and the cavity 154, as shown in FIG. 11 . Then, the heater 66 built in the base 60 heats the resin laminate 152. As a result, the thermosetting resin 182 is heated through the resin laminate 152 and hardens. At this time, the thermosetting resin 182 hardens while covering the side surface of the component body 176. That is, in the electronic component 172 mounted inside the cavity 154, the thermosetting resins 171, 182 are sealed between the upper surface of the resin laminate 152 and the lower surface of the component body 176, and harden while covering the side surface of the component body 176. As a result, the electronic component 172 mounted inside the cavity 154 is fixed by the hardened resin.

[0036] In this manner, the electronic components 172 mounted inside the cavities 154 of the resin laminate 157 are fixed by the cured resin, thereby forming the circuit board 190 on the upper surface of the base 60. However, since the electronic components 172 are mounted on the circuit board 190 after the resin laminate 157 is formed, there is a possibility that components of the resin laminate 157 may adhere to the wiring 162 during the formation of the resin laminate 157. In this case, there is a possibility that the electrical connection between the wiring 162 and the electronic components 172 may be affected. More specifically, during the formation of the circuit board 190, the resin laminate 157 is formed so that the ends of the wiring 162 before the electronic components 172 are mounted are exposed inside the cavities 154, as shown in FIG. 5 . At this time, there is a possibility that volatile components of the ultraviolet-curable resin used to form the resin laminate 157 may adhere to the surfaces of the wiring 162 exposed inside the cavities 154. In this case, the volatile components of the ultraviolet curing resin adhering to the surface of the wiring 162 exposed inside the cavity 154 may affect the electrical connection between the wiring 162 and the electronic component 172 .

[0037] Furthermore, since the electronic components 172 are mounted on the circuit board 190 after the resin laminate 157 is formed, when the electronic components 172 are pressed against the circuit board 190 by the pressing plate 122 via the rubber plate 124, the rubber plate 124 may come into contact with the upper surface of the resin laminate 157. More specifically, when the circuit board 190 is formed, the electronic components 172 are mounted inside the cavities 154 of the resin laminate 157 as shown in FIG. 9 . Then, as shown in FIG. 10 , the electronic components 172 are pressed against the circuit board 190 by the pressing plate 122 via the rubber plate 124. Note that, in order to press the electronic components 172 mounted inside the cavities 154 of the resin laminate 157 with the rubber plate 124, the thickness of the resin laminate 157 is designed so that the upper surface of the resin laminate 157 is lower than the upper surfaces of the electronic components 172 mounted inside the cavities 154. However, when the electronic component 172 is pressed by the rubber plate 124, the rubber plate 124 may deform and come into contact with the upper surface of the resin laminate 157. In such a case, the pressing force of the pressing plate 122 is set taking into consideration that the rubber plate 124 may deform and come into contact with the upper surface of the resin laminate 157. For this reason, when forming the circuit board 190, it is necessary to operate the pressing plate 122 with a pressing force greater than the pressing force when pressing only the electronic component 172.

[0038] Furthermore, as described above, in order to press the electronic component 172 mounted inside the cavity 154 with the rubber plate 124, the thickness dimension of the resin laminate 157 is designed so that the upper surface of the resin laminate 157 is lower than the upper surface of the electronic component 172 mounted inside the cavity 154. In order to make the resin laminate 157 thicker, it is necessary to laminate-model a resin film on the upper surface of the shaped resin laminate 157 after the electronic component 172 is mounted.

[0039] In consideration of this, after the electronic components 172 are mounted on the upper surface of the resin laminate 152, a resin laminate functioning as a resist layer is formed on the upper surface of the resin laminate 152 other than the electronic components 172. More specifically, when the wiring 162 is formed on the resin laminate 152 as shown in FIG. 4 , the dispenser 106 in the first discharging section 100 of the third modeling unit 24 discharges conductive paste 166 onto the end of the wiring 162 as shown in FIG. 12 . Then, the resin laminate 152 is heated by the heater 66 built in the base 60. As a result, the conductive paste 166 is heated and hardened via the resin laminate 152, and the conductive paste 166 exhibits conductivity and becomes bumps 168.

[0040] Furthermore, in the first dispensing section 100 of the third modeling unit 24, the dispenser 106 dispenses the conductive paste 170 onto the bumps 168, as shown in Fig. 13. Note that at the timing when the conductive paste 170 is dispensed onto the bumps 168, the conductive paste 170 has not been heated and has not yet hardened.

[0041] Subsequently, in the second discharging section 110 of the fourth modeling unit 25, the dispenser 116 discharges the thermosetting resin 171 onto the upper surface of the resin laminate 152 between the wires 162, as shown in FIG.

[0042] 15 , the mounting unit 27 mounts the electronic component 172 so that the electrodes 178 of the electronic component 172 come into contact with the conductive paste 170 dispensed onto the bumps 168 formed on the wiring 162. At this time, the component body 176 of the electronic component 172 comes into contact with the thermosetting resin 171 dispensed between the wiring 162.

[0043] When the electronic component 172 is mounted in this manner, as shown in FIG. 16 , the electronic component 172 is pressed downward by the pressing plate 122 via the rubber plate 124 in the pressing portion 120 of the pressing unit 26. While the electronic component 172 is being pressed by the pressing unit 26, the heater 66 built into the base 60 heats the resin laminate 152. This heats and hardens the conductive paste 170 and thermosetting resin 171 via the resin laminate 152. At this time, the hardened conductive paste 170 exhibits conductivity and functions as a bump. Therefore, the bump 180 is formed by the bump 168 formed by hardening the conductive paste 166 and the bump formed by hardening the conductive paste 170. Pressing the electronic component 172 with the pressing plate 122 in this manner brings the component body 176 and the thermosetting resin 171 into close contact with each other, and also brings the electrodes 178 and the bumps 180 into close contact with each other. As a result, the adhesive force of the thermosetting resin 171 fixes the electronic component 172 to the upper surface of the resin laminate 152 in the component body 176, and the adhesive force between the electrodes 178 and the bumps 180 ensures electrical connection between the electronic component 172 and the wiring 162. When the electronic component 172 is pressed by the pressing plate 122 via the rubber plate 124, the rubber plate 124 is deformed, but the deformed rubber plate 124 does not contact the upper surface of the resin laminate 152. For this reason, the pressing force is set so as to press only the electronic component 172. When the electronic component 172 is pressed by the pressing plate 122 via the rubber plate 124, the deformed rubber plate 124 may contact the upper surface of the resin laminate 152. In this case, the pressing force of the pressing plate 122 can be set smaller than when the resin laminate 157 is formed on the resin laminate 152.

[0044] When the electronic component 172 is pressed by the rubber plate 124 in this manner, the inkjet head 88 in the second printing unit 84 of the second modeling unit 23 ejects a thin film of ultraviolet curable resin onto the upper surface of the resin laminate 152 excluding the electronic component 172. That is, the ultraviolet curable resin is ejected onto the upper surface of the resin laminate 152 in a thin film form so that the electronic component 172 attached to the upper surface of the resin laminate 152 is exposed. Next, in the curing unit 86, the irradiation device 92 irradiates the thin film of ultraviolet curable resin with ultraviolet light. As a result, as shown in FIG. 17 , a resin layer 200 is formed on the upper surface of the resin laminate 152 excluding the electronic component 172. Note that a slight gap is formed between the electronic component 172 and the resin layer 200, and the gap is set to, for example, the dimensional tolerance of the electronic component 172 (specifically, 100 to 200 μm).

[0045] Next, the inkjet head 88 ejects a thin film of ultraviolet curable resin only onto the resin layer 200. That is, the inkjet head 88 ejects the ultraviolet curable resin onto the resin layer 200 so as to expose the electronic components 172. The irradiation device 92 then irradiates the ejected thin film of ultraviolet curable resin with ultraviolet light, thereby laminating the resin layer 200 on top of the resin layer 200. In this manner, the ejection of ultraviolet curable resin onto the resin layer 200 and the irradiation of ultraviolet light are repeated, laminating multiple resin layers 200, thereby forming a resin laminate 202. In this manner, the resin laminate 202 is formed on the resin laminate 152. The thickness of the resin laminate 202 is set so that the top surface of the resin laminate 202 is higher than the top surfaces of the electronic components 172 attached to the resin laminate 152. The resin laminate 202 covers the wiring 162 except for the ends to which the electrodes 178 of the electronic components 172 are connected, and the resin laminate 202 functions as a resist layer. A gap is formed between the electronic component 172 and the resin laminate 202 , and this gap is the same as the gap between the electronic component 172 and the resin layer 200 .

[0046] Before the resin laminate 202 is formed on the upper surface of the resin laminate 152, the electronic component 172 is pressed by the rubber plate 124. During this process, the bumps 180 are crushed by the electrodes 178 of the electronic component 172, causing them to protrude beyond the outer edges of the electrodes 178, as shown in Fig. 16 . For this reason, as shown in Fig. 17 , the resin laminate 202, which is formed so as to surround the side surfaces of the electronic component 172 with a small gap, covers the bumps 180 that protrude beyond the outer edges of the electrodes 178. In other words, the resin laminate 202 is formed so close to the electronic component 172 that it covers the bumps 180 that protrude beyond the outer edges of the electrodes 178.

[0047] Furthermore, the amount of thermosetting resin 171 dispensed at the planned mounting position of component body 176 of electronic component 172 is set based on the volume between component body 176 and resin laminate 152 when electronic component 172 is mounted on the top surface of resin laminate 152. In other words, the amount of thermosetting resin 171 dispensed is set so that thermosetting resin 171 does not protrude outside the outer edge of component body 176 when electronic component 172 is mounted on the top surface of resin laminate 152. However, when electronic component 172 is pressed by rubber plate 124, as shown in FIG. 18 , thermosetting resin 171 may be crushed by component body 176 of electronic component 172 and protrude outside the outer edge of component body 176. Note that while FIG. 16 is a cross-sectional view of a portion including wiring 162, electrodes 178, and bumps 180, FIG. 18 is a cross-sectional view of a portion not including wiring 162, electrodes 178, and bumps 180. 19, the resin laminate 202 formed to surround the side surfaces of the electronic component 172 with a small gap covers the thermosetting resin 171 that protrudes outward from the outer edge of the component body 176. In other words, the resin laminate 202 is formed so close to the electronic component 172 that it covers the thermosetting resin 171 that protrudes outward from the outer edge of the component body 176. Note that while FIG. 17 is a cross-sectional view of a portion including the wiring 162, the electrodes 178, and the bumps 180, FIG. 19 is a cross-sectional view of a portion that does not include the wiring 162, the electrodes 178, and the bumps 180.

[0048] In this manner, the resin laminate 202 is formed on the upper surface of the resin laminate 152 in proximity to the electronic components 172, thereby forming a circuit board 210 on the upper surface of the base 60, as shown in FIGS. 17 and 19 . When forming the circuit board 210, the electronic components 172 are mounted, and then the resin laminate 202 is formed on the upper surface of the resin laminate 152. That is, the electrodes 178 of the electronic components 172 are connected to the wiring 162 via the bumps 180, and then the resin laminate 202 is formed on the upper surface of the resin laminate 152. Therefore, when forming the resin laminate 202, volatile components of the ultraviolet-curable resin used to form the resin laminate 202 do not adhere to the connection portions of the wiring 162 to the electrodes 178. This eliminates the possibility that the volatile components of the ultraviolet-curable resin will affect the electrical connection between the wiring 162 and the electronic components 172 in the circuit board 210, ensuring appropriate conduction between the wiring 162 and the electronic components 172.

[0049] Furthermore, because the resin laminate 202 is formed on the upper surface of the resin laminate 152 after the electronic component 172 is mounted, the electronic component 172 can be pressed by the rubber plate 124 before the resin laminate 202 is formed, as shown in FIG. 16 . Therefore, the pressing force of the rubber plate 124 when forming the circuit board 210 can be set so as to press only the electronic component 172. This allows the pressing force of the rubber plate 124 when forming the circuit board 210 to be smaller than the pressing force of the rubber plate 124 when forming the circuit board 190. Note that when the electronic component 172 is pressed by the pressing plate 122 via the rubber plate 124, the deformed rubber plate 124 may come into contact with the upper surface of the resin laminate 152. Even in this case, the pressing force of the pressing plate 122 can be smaller than when the resin laminate 157 is formed on the resin laminate 152.

[0050] Furthermore, because the electronic component 172 can be pressed by the rubber plate 124 before the resin laminate 202 is formed, the upper surface of the resin laminate 202 can be made higher than the upper surfaces of the electronic components 172 mounted on the resin laminate 152. Therefore, the thickness of the resin laminate 202 is set so that the upper surface of the resin laminate 202 is higher than the upper surfaces of the electronic components 172 mounted on the resin laminate 152. As can be seen from a comparison of FIGS. 11 and 17 , this makes it possible to make the thickness of the resin laminate 202, which functions as a resist layer for the circuit board 210, thicker than the thickness of the resin laminate 157, which functions as a resist layer for the circuit board 190. This makes it possible, for example, to further suppress warping of the circuit board 210.

[0051] 17 , in the circuit board 210, the resin laminate 202 is formed so as to surround the side surfaces of the electronic components 172 with a small gap. Therefore, it is not necessary to cover the side surfaces of the electronic components 172 with a thermosetting resin. This eliminates the need for a step of covering the side surfaces of the electronic components 172 with a thermosetting resin when forming the circuit board 210, and it is possible to shorten the time required to form the circuit board 210.

[0052] 2, the controller 140 of the control device 28 has a wiring forming unit 220, a first discharging unit 222, a second discharging unit 224, a mounting unit 226, and a resin layer forming unit 228. The wiring forming unit 220 is a functional unit for forming the wiring 162 on the resin laminate 152. The first discharging unit 222 is a functional unit for discharging the conductive pastes 166 and 170 to the intended mounting positions of the electrodes 178 on the wiring 162. The second discharging unit 224 is a functional unit for discharging the thermosetting resin 171 to the intended mounting positions of the component main body 176 on the resin laminate 152. The mounting unit 226 is a functional unit for mounting the electronic component 172 on the upper surface of the resin laminate 152 so that the electrodes 178 contact the wiring 162 via the bumps 180. The resin layer forming section 228 is a functional section for forming a resin laminate 202 that covers the wiring 162 by stacking a resin layer 200 formed by discharging ultraviolet curable resin after the electronic component 172 is attached to the upper surface of the resin laminate 152.

[0053] In the above embodiment, the circuit forming apparatus 10 is an example of a circuit forming apparatus. The control device 28 is an example of a control device. The inkjet head 76 is an example of a metal-containing liquid ejection device. The inkjet head 88 is an example of a resin ejection device. The mounting unit 132 is an example of a mounting device. The resin laminate 152 is an example of a first resin layer. The metal ink 160 is an example of a metal-containing liquid. The wiring 162 is an example of a wiring. The conductive paste 166 is an example of a conductive paste. The conductive paste 170 is an example of a conductive paste. The thermosetting resin 171 is an example of an underfill. The electronic component 172 is an example of an electronic component. The component body 176 is an example of a component holder. The electrode 178 is an example of an electrode. The resin layer 200 is an example of a curable resin layer. The resin laminate 202 is an example of a second resin layer. Furthermore, the steps and processes performed by the wiring forming unit 220 are examples of a wiring forming step and a wiring forming process. The steps performed by the first discharging unit 222 are an example of a first discharging step. The steps performed by the second discharging unit 224 are an example of a second discharging step. The steps and processes performed by the mounting unit 226 are an example of a mounting step and a mounting process. The steps and processes performed by the resin layer forming unit 228 are an example of a resin layer forming step and a resin layer forming process.

[0054] As described above, the present embodiment has the following advantages.

[0055] Wiring 162 is formed on the upper surface of resin laminate 152, and electronic component 172 is mounted on the upper surface of resin laminate 152 so that electrodes 178 contact wiring 162. After electronic component 172 is mounted, a resin layer 200 is formed by discharging a film of ultraviolet-curable resin onto the upper surface of resin laminate 152 other than electronic component 172, and multiple resin layers 200 are stacked to form a resin laminate 202 that covers wiring 162. This prevents volatile components of the ultraviolet-curable resin used to form resin laminate 202 from adhering to the connection portions of wiring 162 to electrodes 178, ensuring appropriate conduction between wiring 162 and electronic component 172. Furthermore, the pressing force when electronic component 172 is pressed by rubber plate 124 can be reduced.

[0056] Furthermore, conductive pastes 166, 170 are discharged onto wiring 162 at positions where electrodes 178 are to be attached, and electronic component 172 is attached so that electrode 178 comes into contact with wiring 162 via conductive pastes 166, 170. Then, resin laminate 202 is formed so as to cover conductive pastes 166, 170 that protrude beyond the outer edge of electrode 178. This allows resin laminate 202 to be formed in such a state that resin laminate 202 covers conductive pastes 166, 170 that protrude beyond the outer edge of electrode 178, and so close to electronic component 172.

[0057] Furthermore, the resin laminate 202 is formed so that the upper surface of the resin laminate 202 is higher than the upper surfaces of the electronic components 172 mounted on the resin laminate 152. This allows the resin laminate 202 to be thicker. This makes it possible to further suppress warping of the circuit board 210, for example.

[0058] Furthermore, thermosetting resin 171 is dispensed onto the intended mounting position of component body 176 of electronic component 172, and electronic component 172 is mounted so that component body 176 comes into contact with thermosetting resin 171. Then, resin laminate 202 is formed so as to cover the thermosetting resin 171 that protrudes outside the outer edge of component body 176. This allows resin laminate 202 to be formed in such a state that it covers the thermosetting resin 171 that protrudes outside the outer edge of component body 176.

[0059] The present invention is not limited to the above-described embodiment, and various modifications and improvements can be made based on the knowledge of those skilled in the art. For example, in the above-described embodiment, the resin laminate 202 is formed with a small gap between it and the side surface of the electronic component 172. However, as shown in FIG. 20 , the resin laminate 230 may be formed with a predetermined distance between it and the side surface of the electronic component 172. When the resin laminate 230 is formed with a predetermined distance between it and the side surface of the electronic component 172, the bumps 180 extending beyond the outer edges of the electrodes 178, i.e., the conductive pastes 166 and 170, do not need to be covered by the resin laminate 230. Then, as shown in FIG. 21 , a thermosetting resin 232 is dispensed into the predetermined gap between the resin laminate 230 and the side surface of the electronic component 172, and the resin laminate 152 is heated by a heater 66 built into the base 60. The thermosetting resin 232 is heated and hardened through the resin laminate 152, forming a circuit board 236. The circuit board 236 thus formed can also achieve the same effects as the circuit board 210 described above.

[0060] In the above embodiment, an ultraviolet curable resin is used as the resin forming the resin laminates 152, 202, and a thermosetting resin is used as the resin formed on the underside of the component body 176 of the electronic component 172. In other words, the resin forming the resin laminates 152, 202 and the resin formed on the underside of the component body 176 of the electronic component 172 are different curable resins. On the other hand, the resin forming the resin laminates 152, 202 and the resin formed on the underside of the component body 176 of the electronic component 172 may be the same curable resin.

[0061] In the above embodiment, the conductive paste 170 is dispensed onto the bumps 168 formed on the wiring 162, and the electronic component 172 is mounted on the upper surface of the resin laminate 152 so that the electrodes 178 contact the conductive paste 170. On the other hand, the electronic component 172 may be mounted on the upper surface of the resin laminate 152 so that the electrodes 178 contact the bumps 168 without dispensing the conductive paste 170 onto the bumps 168.

[0062] This specification also discloses the technical idea of ​​changing "the circuit formation method according to claim 1" in claim 3 originally filed to "the circuit formation method according to claim 1 or claim 2."

[0063] 10: Circuit forming apparatus (circuit forming apparatus) 28: Control device 76: Inkjet head (metal-containing liquid ejection device) 88: Inkjet head (resin ejection device) 132: Mounting unit (mounting device) 152: Resin laminate (first resin layer) 160: Metal ink (metal-containing liquid) 162: Wiring (metal wiring) 166: Conductive paste 170: Conductive paste 171: Thermosetting resin (underfill) 172: Electronic component 176: Component body 178: Electrode 200: Resin layer (curable resin layer) 202: Resin laminate (second resin layer) 220: Wiring forming unit (wiring forming process) (wiring forming treatment) 222: First ejection unit (first ejection treatment) 224: Second ejection unit (second ejection treatment) 226: Mounting unit (mounting process) (mounting treatment) 228: Resin layer forming section (resin layer forming step) (resin layer forming treatment) 230: Resin laminate (second resin layer)

Claims

1. A circuit forming method comprising: a wiring forming step of forming wiring on the upper surface of a first resin layer using a metal-containing liquid; a mounting step of mounting an electronic component on the upper surface of the first resin layer so that electrodes of the electronic component contact the wiring; and a resin layer forming step of, after the electronic component has been mounted on the upper surface of the first resin layer, ejecting a curable resin onto the upper surface of the first resin layer excluding the electronic component to form and stack a layer of the curable resin, thereby forming a second resin layer that covers the wiring.

2. A circuit forming method as described in claim 1, further comprising a first discharging step of discharging conductive paste onto the intended position of the electrode on the wiring formed on the upper surface of the first resin layer, wherein in the mounting step, the electronic component is mounted so that the electrode contacts the wiring via the conductive paste, and in the resin layer forming step, the second resin layer is formed so as to cover at least a portion of the conductive paste that extends outside the outer edge of the electrode.

3. The circuit forming method according to claim 1, wherein in the resin layer forming step, the second resin layer is formed so that the upper surface of the second resin layer is higher than the upper surfaces of the electronic components mounted on the upper surface of the first resin layer.

4. A circuit forming method as claimed in any one of claims 1 to 3, further comprising a second dispensing step of discharging underfill onto the intended mounting position of the component body of the electronic component before the electronic component is mounted on the top surface of the first resin layer, wherein in the mounting step, the electronic component is mounted so that the component body comes into contact with the underfill, and in the resin layer forming step, the second resin layer is formed so as to cover at least a portion of the underfill that extends outside the outer edge of the component body.

5. A circuit forming device comprising: a metal-containing liquid discharging device that discharges a metal-containing liquid; a mounting device that performs mounting work of electronic components; a resin discharging device that discharges a curable resin; and a control device, wherein the control device performs the following: a wiring forming process that forms wiring by discharging the metal-containing liquid onto the upper surface of a first resin layer using the metal-containing liquid discharging device; a mounting process that mounts the electronic component on the upper surface of the first resin layer using the mounting device so that electrodes of the electronic component contact the wiring; and a resin layer forming process that forms a second resin layer that covers the wiring by discharging the curable resin using the resin discharging device onto the upper surface of the first resin layer excluding the electronic component after the electronic component has been mounted on the upper surface of the first resin layer, thereby forming and stacking a layer of the curable resin.

Images