JP7358614B2 - Wiring formation method - Google Patents

Description

The present disclosure relates to a wiring forming method for forming wiring using a fluid containing metal particles by three-dimensional additive manufacturing.

BACKGROUND ART In recent years, as described in Patent Document 1 below, a technology has been developed for forming a circuit for connecting electronic components and the like by discharging a fluid containing metal particles and firing the discharged fluid. In the wiring forming method disclosed in Patent Document 1, a first wiring is formed using a fluid containing metal particles, and a resin layer is formed on the first wiring using an ultraviolet curing resin. Via holes are formed in the resin layer. The inner wall of the via hole is inclined, and the lower end of the inclined surface is continuous with the upper surface of the first wiring. A second wiring is formed on the resin layer to be connected to the first wiring via the inclined surface of the via hole.

International publication WO2016-189557

According to the technology described in Patent Document 1 mentioned above, the first wiring arranged under the resin layer and the second wiring arranged on the upper surface of the resin layer are formed in the via hole by three-dimensional additive manufacturing. Connection can be made by wiring formed on the inclined surface. For example, when a fluid containing metal particles is discharged onto the slope of a via hole using an inkjet method, if the angle of the slope is steep, the discharged fluid may flow down along the slope. . As a result, there is a risk that the thickness of the wiring may be locally reduced or a disconnection may occur, which poses a problem in that the reliability of the connection decreases.

The present disclosure has been made in view of the above-mentioned circumstances, and an object of the present disclosure is to provide a wiring forming method that can improve the reliability of wiring connections when wiring is formed on an inclined surface by three-dimensional additive manufacturing. do.

In order to solve the above problems, the present disclosure includes a pedestal member forming step in which a pedestal member having a predetermined height is formed from a resin material, and a state in which a part of the wiring is raised from the bottom by a fluid containing metal particles. A first wiring forming step of forming a first wiring that connects from a position where the pedestal member is not formed to a surface of the pedestal member, and a part of the pedestal member and the first wiring are exposed. a resin layer forming step of forming a resin layer covering the pedestal member and the first wiring and having an inclined surface formed in accordance with the position of the pedestal member; and a fluid containing metal particles . a second wiring forming step of forming a second wiring that connects to the upper surface of the resin layer on a part of the inclined surface, and forming the second wiring so as to be connected to the first wiring on the pedestal member; In the resin layer forming step, a via hole is formed in the resin layer that penetrates the resin layer and has the inclined surface on the inner wall, and the upper surface of the resin layer is higher than the surface of the pedestal member. the inclined surface of the resin layer is inclined in a direction away from the pedestal member from the bottom to the top, and the pedestal member has a shape matching the via hole. .

According to the wiring forming method of the present disclosure, the first wiring is formed on the pedestal member. An inclined surface is formed to match the position of the pedestal member, and a second wiring is formed on the inclined surface. The second wiring and the first wiring on the pedestal member are connected. Thereby, by forming the first wiring on the pedestal member, it is possible to raise the bottom of the first wiring to a predetermined height. By bringing the first wiring to a higher position, the angle of the slope can be made gentler and the second wiring can be connected. When forming the second wiring, it is possible to suppress the fluid containing metal particles from flowing down on the inclined surface, and it is possible to form the second wiring with a more uniform thickness, thereby suppressing the occurrence of disconnection. The reliability of the connection of the second wiring can be improved.

FIG. 1 is a diagram showing an electronic device manufacturing apparatus. FIG. 2 is a block diagram showing a control device. FIG. 2 is a block diagram showing a control device. FIG. 3 is a schematic diagram for explaining a wiring formation process. FIG. 3 is a schematic diagram for explaining a wiring formation process. FIG. 3 is a schematic diagram for explaining a wiring formation process. FIG. 3 is a schematic diagram for explaining a wiring formation process. FIG. 3 is a schematic diagram for explaining a wiring formation process. FIG. 3 is a plan view of a resin layer. FIG. 3 is a cross-sectional view of wiring and a resin layer in a comparative example. FIG. 7 is a diagram showing a state in which multiple sets of wiring are connected by one via hole in another example. FIG. 2 is a schematic diagram showing the surface of a pedestal member on which a plurality of wirings are formed. FIG. 7 is a diagram showing a state in which multiple sets of wiring are connected by one via hole in another example. FIG. 2 is a plan view of a state in which electronic components are mounted. FIG. 7 is a cross-sectional view of another example of an inclined surface.

(Configuration of electronic device manufacturing equipment)
Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. FIG. 1 shows an electronic device manufacturing apparatus 10. The electronic device manufacturing apparatus 10 includes a transport device 20, a first modeling unit 22, a second modeling unit 24, a mounting unit 26, a third modeling unit 29, and a control device 27 (see FIGS. 2 and 3). Be prepared. The transport device 20 , the first modeling unit 22 , the second shaping unit 24 , the mounting unit 26 , and the third shaping unit 29 are arranged on the base 28 of the electronic device manufacturing apparatus 10 . The base 28 has a generally rectangular shape in plan view. In the following description, the longitudinal direction of the base 28 will be referred to as the X-axis direction, the lateral direction of the base 28 will be referred to as the Y-axis direction, and the direction perpendicular to both the X-axis direction and the Y-axis direction will be referred to as the Z-axis direction.

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 arranged on the base 28 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. Further, the X-axis slide mechanism 30 includes an electromagnetic motor 38 (see FIG. 2), and the electromagnetic motor 38 is driven to move the X-axis slider 36 to any position in the X-axis direction. Further, the Y-axis slide mechanism 32 includes a Y-axis slide rail 50 and a stage 52. The Y-axis slide rail 50 is arranged on the base 28 so as to extend in the Y-axis direction. One end of the Y-axis slide rail 50 is connected to the X-axis slider 36. Therefore, the Y-axis slide rail 50 is movable in the X-axis direction. The stage 52 is held by a Y-axis slide rail 50 so as to be slidable in the Y-axis direction. The Y-axis slide mechanism 32 includes an electromagnetic motor 56 (see FIG. 2), and is driven by the electromagnetic motor 56 to move the stage 52 to an arbitrary position in the Y-axis direction. Thereby, the stage 52 is moved to an arbitrary position on the base 28 by driving the X-axis slide mechanism 30 and the Y-axis slide mechanism 32.

The stage 52 includes a base 60, a holding device 62, and a lifting device 64. The base 60 is formed into a flat plate shape, and the base material 70 is placed on the upper surface. The holding device 62 is provided on both sides of the base 60 in the X-axis direction. The holding device 62 securely holds the base material 70 with respect to the base 60 by sandwiching both edges of the base material 70 placed on the base 60 in the X-axis direction. Further, the lifting device 64 is disposed below the base 60 and raises and lowers the base 60 in the Z-axis direction.

The first modeling unit 22 is a unit that models wiring on the base material 70 placed on the base 60 of the stage 52, and includes a first printing section 72 and a firing section 74. The first printing section 72 has an inkjet head 76 (see FIG. 2), and discharges conductive ink linearly onto the base material 70 placed on the base 60. Conductive ink is an example of a fluid containing metal particles of the present disclosure. The conductive ink includes, for example, nanometer-sized fine particles of metal (such as silver) as a main component dispersed in a solvent, and is cured by being fired with heat. The conductive ink contains, for example, metal nanoparticles with a size of several hundred nanometers or less. For example, the surface of the metal nanoparticles is coated with a dispersant to suppress aggregation in a solvent.

Note that the inkjet head 76 ejects conductive ink from a plurality of nozzles using, for example, a piezo system using piezoelectric elements. Further, the device for discharging conductive ink (fluid containing metal nanoparticles) is not limited to an inkjet head having a plurality of nozzles, but may be a dispenser having one nozzle, for example. Furthermore, the type of metal nanoparticles contained in the conductive ink is not limited to silver, but may also be copper, gold, or the like. Moreover, the number of types of metal nanoparticles contained in the conductive ink is not limited to one type, but may be multiple types.

The baking section 74 has an irradiation device 78 (see FIG. 2). The irradiation device 78 includes, for example, an infrared heater that heats the conductive ink discharged onto the base material 70. The conductive ink is fired by applying heat from an infrared heater to form wiring. Firing the conductive ink here means, for example, that by applying energy, the solvent is vaporized and the protective film of the metal nanoparticles, in other words, the dispersant is decomposed, and the metal nanoparticles come into contact or fuse together. This is a phenomenon in which the conductivity increases. Then, wiring can be formed by firing the conductive ink. Note that the device for heating the conductive ink is not limited to an infrared heater. For example, the electronic device manufacturing apparatus 10 uses an infrared lamp, a laser irradiation device that irradiates the conductive ink with laser light as a device that heats the conductive ink, or places the base material 70 onto which the conductive ink has been discharged in a furnace. It may also be provided with an electric furnace for heating.

Further, the second modeling unit 24 is a unit that models a resin layer on the base material 70 placed on the base 60, and includes a second printing section 84 and a curing section 86. The second printing section 84 has an inkjet head 88 (see FIG. 2), and discharges ultraviolet curing resin onto the base material 70 placed on the base 60. Ultraviolet curable resin is a resin that is cured by irradiation with ultraviolet rays. Note that the method by which the inkjet head 88 ejects the ultraviolet curable resin may be, for example, a piezo method using a piezoelectric element, or a thermal method in which the resin is heated to generate bubbles and then ejected from a plurality of nozzles.

The curing section 86 includes a flattening device 90 (see FIG. 2) and an irradiation device 92 (see FIG. 2). The flattening device 90 flattens the upper surface of the ultraviolet curing resin discharged onto the base material 70 by the inkjet head 88. The flattening device 90 makes the thickness of the ultraviolet curable resin uniform, for example, by leveling the surface of the ultraviolet curable resin and scraping off excess resin with a roller or blade. Further, the irradiation device 92 includes a mercury lamp or an LED as a light source, and irradiates the ultraviolet curing resin discharged onto the base material 70 with ultraviolet rays. Thereby, the ultraviolet curing resin discharged onto the base material 70 is cured, and a resin layer can be formed.

Furthermore, the mounting unit 26 is a unit that arranges electronic components on the base material 70 placed on the base 60, and includes a supply section 100 and a mounting section 102. The supply unit 100 has a plurality of tape feeders 110 (see FIG. 2) that feed out taped electronic components one by one, and supplies the electronic components at each supply position. The electronic component is, for example, a sensor element such as a temperature sensor. Note that the supply of electronic components is not limited to the supply by the tape feeder 110, and may be supplied by a tray.

The mounting section 102 includes a mounting head 112 (see FIG. 2) and a moving device 114 (see FIG. 2). The mounting head 112 has a suction nozzle for suctioning and holding electronic components. The suction nozzle is supplied with negative pressure from a positive and negative pressure supply device (not shown), and suctions and holds the electronic component by suctioning air. Then, by supplying a slight positive pressure from the positive/negative pressure supply device, the electronic component is detached. Further, the moving device 114 moves the mounting head 112 between the supply position of the tape feeder 110 and the base material 70 placed on the base 60. Thereby, the mounting section 102 holds the electronic component using the suction nozzle, and places the electronic component held using the suction nozzle on the base material 70 .

Further, the third modeling unit 29 is a unit that applies conductive paste onto the base material 70 placed on the base 60. The conductive paste is, for example, a viscous fluid containing micro-sized metal particles (such as microfila) in a resin adhesive. The micro-sized metal microparticles are, for example, metal (such as silver) in a flake state. The metal microparticles are not limited to silver, but may also be gold, copper, or multiple types of metals. The adhesive contains, for example, an epoxy resin as a main component. The conductive paste is cured by heating and is used, for example, to form connection terminals connected to wiring. The connection terminal is, for example, a bump connected to a component terminal of an electronic component, an external electrode connected to an external device, or the like.

Further, the third modeling unit 29 includes a dispenser 130 as a device for discharging (applying) the conductive paste. Note that the device for applying the conductive paste is not limited to a dispenser, and may be a screen printing device or a gravure printing device. Furthermore, "coating" in the present disclosure is a concept that includes an operation of discharging a fluid from a nozzle or the like, and an operation of depositing a fluid onto an object by screen printing or gravure printing. The dispenser 130 discharges the conductive paste onto the base material 70 and the resin layer. The discharged conductive paste is heated and hardened by, for example, the firing section 74 of the first modeling unit 22, thereby forming a connection terminal (external electrode, etc.).

Here, the conductive paste contains, for example, metal microparticles with a size of several tens of micrometers or less. When the conductive paste is heated, the adhesive (resin, etc.) is cured, and the metal flakes are cured in a state where they are in contact with each other. As described above, in the conductive ink, metal nanoparticles are fused together by heating, for example, to become an integrated metal, and the conductivity is higher than that in a state where the metal nanoparticles are only in contact with each other. On the other hand, the conductive paste is cured by bringing micro-sized metal microparticles into contact with each other by curing the adhesive. For this reason, the resistance (electrical resistivity) of wiring formed by curing conductive ink is extremely small, for example, from several to several tens of microΩcm, and the resistance (electrical resistivity) of wiring formed by curing conductive paste is extremely small, for example, from several to several tens of microΩcm. 1,000 microΩ・cm). Therefore, conductive ink is suitable for modeling objects that require a low resistance value, such as low-resistance circuit wiring.

On the other hand, conductive paste can improve adhesion to other members by curing the adhesive during curing, and has superior adhesion to other members than conductive ink. The other members mentioned here are members to which a conductive paste is applied by discharging or the like, and include, for example, resin layers, wiring, component terminals of electronic parts, and the like. Therefore, the conductive paste is suitable for forming objects that require mechanical strength (such as tensile strength), such as connection terminals for fixing electronic components to a resin layer. In the electronic device manufacturing apparatus 10 of this embodiment, an electronic circuit with improved electrical properties and mechanical properties can be manufactured by selectively using such conductive ink and conductive paste to take advantage of their characteristics.

Next, the configuration of the control device 27 of the electronic device manufacturing apparatus 10 will be explained. As shown in FIGS. 2 and 3, the control device 27 includes a controller 120, a plurality of drive circuits 122, and a storage device 124. The plurality of drive circuits 122 include the electromagnetic motors 38 and 56, the holding device 62, the lifting device 64, the inkjet head 76, the irradiation device 78, the inkjet head 88, the flattening device 90, the irradiation device 92, the tape feeder 110, and the mounting head 112. , connected to the mobile device 114 (see FIG. 2). Furthermore, the drive circuit 122 is connected to the third modeling unit 29 (see FIG. 3).

The controller 120 is mainly a computer, including a CPU, ROM, RAM, etc., and is connected to a plurality of drive circuits 122. The storage device 124 includes a RAM, ROM, hard disk, etc., and stores a control program 126 that controls the electronic device manufacturing apparatus 10. The controller 120 can control the operations of the transport device 20, the first modeling unit 22, the second modeling unit 24, the mounting unit 26, the third modeling unit 29, etc. by executing the control program 126 on the CPU. . In the following description, the fact that the controller 120 executes the control program 126 to control each device may be simply referred to as "the device." For example, "the controller 120 moves the stage 52" means "the controller 120 executes the control program 126, controls the operation of the transport device 20 via the drive circuit 122, and moves the stage 52 by the operation of the transport device 20." 52.

(Operation of electronic device manufacturing equipment)
The electronic device manufacturing apparatus 10 of this embodiment uses the above-described configuration to manufacture an electronic device including wiring, connection terminals, and electronic components as a shaped object. In the following description, a case will be described in which a circuit board on which electronic components are mounted is manufactured as an electronic device (modeled object). Note that the structure, manufacturing procedure, etc. of the modeled object described below are merely examples. Further, for example, the control program 126 of the storage device 124 is set with three-dimensional data of each layer obtained by slicing the completed circuit board. The controller 120 controls the first modeling unit 22 and the like based on the data of the control program 126, and forms a circuit board by discharging and curing ultraviolet curing resin and the like.

First, when the base material 70 is set on the base 60 of the stage 52, the controller 120 shapes an electronic device on the base material 70 while moving the stage 52. As shown in FIG. 4, a release film 150 that can be peeled off by heat, for example, is attached to the upper surface of the base material 70, and a shaped object (such as an electronic device) is formed on the release film 150. . The release film 150 is peeled off from the base material 70 together with the shaped object by being heated. Note that the method for separating the base material 70 and the shaped object is not limited to the method using the release film 150. For example, a member (such as a support material) that can be melted by heat may be placed between the base material 70 and the shaped object, and the parts may be melted and separated. Alternatively, the structure may be formed directly on the base material 70 without using a separating member such as the release film 150.

When the base material 70 is set, the controller 120 forms a pedestal member 149 on the release film 150, as shown in FIG. In the controller 120, a pedestal member 149 is formed to match the position of a via hole 155 in a resin layer 153 (see FIG. 6), which will be described later. The positions of the pedestal member 149 and the via holes 155 are set, for example, in data of the control program 126 stored in the storage device 124. The controller 120 repeats the process of discharging the ultraviolet curable resin from the inkjet head 88 of the second modeling unit 24 onto the release film 150 and the process of irradiating the ejected ultraviolet curable resin with ultraviolet rays from the irradiation device 92 of the curing section 86. By performing this, the pedestal member 149 is formed.

Specifically, the controller 120 moves the stage 52 below the second modeling unit 24 and controls the second printing section 84 to apply the ultraviolet curing resin from the inkjet head 88 onto the release film 150 in the form of a thin film. Discharge to. The controller 120 controls the inkjet head 88 to eject the ultraviolet curing resin to a position corresponding to the bottom of the via hole 155 (see FIG. 6). The curing section 86 uses an irradiation device 92 to irradiate the thin film of ultraviolet curing resin with ultraviolet rays. As a result, a thin film-like pedestal member is formed on the release film 150. Note that the controller 120 may appropriately execute a process of flattening the ultraviolet curable resin discharged in the form of a thin film using the flattening device 90. The controller 120 adjusts the discharge position of the ultraviolet curable resin to the bottom of the via hole 155, and repeatedly discharges the ultraviolet curable resin and irradiates the ultraviolet rays, thereby forming the pedestal member 149.

Next, the controller 120 moves the stage 52 below the first modeling unit 22. As shown in FIG. 5, the controller 120 controls the first printing unit 72 to cause the inkjet head 76 to eject conductive ink onto the surface of the pedestal member 149 and the release film 150. The inkjet head 76 discharges conductive ink in a linear manner according to the wiring pattern. This wiring pattern is set in the control program 126, for example, depending on the object to be manufactured. The wiring pattern shown in FIG. 5 is, for example, a pattern that connects from a predetermined position of the release film 150 (the right end position in FIG. 5) to the upper surface of the pedestal member 149. The controller 120 of this embodiment connects the lower layer wiring 151 and the upper layer wiring 159 through one via hole 155, as shown in FIG. Therefore, the controller 120 controls the inkjet head 76 to eject conductive ink to a position corresponding to the lower layer wiring 151, for example.

Next, the controller 120 controls the baking section 74 to heat the conductive ink discharged onto the pedestal member 149 and the release film 150 using the infrared heater of the irradiation device 78 . Thereby, by firing the conductive ink, wiring 151 can be formed on the pedestal member 149 and the release film 150, as shown in FIG.

FIG. 9 shows a plan view of a resin layer 153 having via holes 155, which will be described later. Note that FIG. 9 omits illustration of an electronic component 163 (see FIG. 8), which will be described later. Further, FIG. 9 shows the lower layer wiring 151 with a broken line. The pedestal member 149 has a predetermined height H1 (see FIG. 4), for example, and is formed into a thin plate shape that is circular when viewed from above (see FIG. 9). The corners of the pedestal member 149 have a curved shape depending on the viscosity of the conductive ink. As shown in FIG. 5, the wiring 151 is continuously formed from above the release film 150 to above the pedestal member 149. Thereby, the top of the release film 150 and the top of the pedestal member 149 (position at the height H1) can be electrically connected through the wiring 151. In other words, a portion of the wiring 151 is raised by the height H1. Here, for example, when conductive ink is discharged onto the surface or curved surface of the pedestal member 149 using an inkjet method, if the angle of the surface or curved surface is steep, the discharged conductive ink may flow down. As a result, there is a possibility that the thickness of the wiring 151 may be locally reduced or a disconnection may occur. Therefore, the height H1 of the pedestal member 149 and the angle θ1 (see FIG. 4) between the curved surface of the pedestal member 149 and the base material 70 are set to values that prevent the conductive ink forming the wiring 151 from running down as much as possible, or It is preferable to set a value that allows conduction to be achieved by laminating conductive inks.

Further, on the pedestal member 149, wirings 151, 159 and a resin layer 153, which will be described later, are formed (see FIG. 7). Therefore, the height H1 of the pedestal member 149 is preferably a height that does not interfere with the inkjet heads 76, 88, the rollers of the flattening device 90, etc. when forming the wirings 151, 159 and the resin layer 153.

Next, as shown in FIG. 6, the controller 120 forms a resin layer 153 on the release film 150 so as to cover the wiring 151 and the pedestal member 149. When forming the resin layer 153, the controller 120 forms via holes 155 in the resin layer 153 through which the pedestal member 149 and part of the wiring 151 are exposed (see FIG. 9). The controller 120 repeatedly executes the process of discharging the ultraviolet curable resin from the inkjet head 88 of the second modeling unit 24 and the process of irradiating the ejected ultraviolet curable resin with ultraviolet rays from the irradiation device 92 of the curing section 86. A resin layer 153 having via holes 155 is formed.

Specifically, the controller 120 moves the stage 52 below the second modeling unit 24, controls the second printing section 84, and prints ultraviolet curing from the inkjet head 88 so as to cover the wiring 151 and the pedestal member 149. The resin is discharged onto the release film 150 in the form of a thin film. The controller 120 controls the inkjet head 88 to eject the ultraviolet curable resin to locations other than the via hole 155 that exposes the pedestal member 149 and a portion of the wiring 151. That is, the inkjet head 88 exposes a part of the pedestal member 149 and the wiring 151 from the via hole 155, and applies a thin film of ultraviolet curing resin on the release film 150 so as to cover the other parts of the pedestal member 149 and the wiring 151. Discharge in a shape. After the controller 120 discharges the ultraviolet curable resin in a thin film, the flattening device 90 may flatten the resin so that the film thickness is uniform. The curing unit 86 then irradiates the thin film of ultraviolet curing resin with ultraviolet light using the irradiation device 92 . As a result, a thin resin layer is formed on the release film 150.

The controller 120 adjusts the discharge position of the ultraviolet curable resin so as to expose a portion of the pedestal member 149 and the wiring 151, and repeats the discharge of the ultraviolet curable resin, flattening, and irradiation of the ultraviolet rays as appropriate. A resin layer 153 having via holes 155 is formed. As shown in FIG. 6, the controller 120 forms a mortar-shaped via hole 155 with an inclined inner wall. An inclined surface 157 is formed on the inner wall of the via hole 155 so that the inner diameter thereof decreases from the upper opening 155A on the upper side toward the lower opening 155B on the lower side (wiring 151 side). The lower layer wiring 151 and the pedestal member 149 have their upper surfaces exposed through the lower opening 155B of the via hole 155 (see FIG. 9).

As shown in FIG. 9, when the resin layer 153 (substrate) is viewed from above, the pedestal member 149 has, for example, a disk shape formed with an inner diameter longer than the circular lower opening 155B (via hole 155). I am doing it. In this way, the pedestal member 149 has a shape that matches the via hole 155, for example, and is formed in a shape that is longer (has a larger outer diameter) than the inner diameter of the via hole 155.

Therefore, the pedestal member 149 of this embodiment is formed to have a size larger than the size of the lower opening 155B formed at the bottom side of the via hole 155 when the via hole 155 is viewed from above. According to this, the pedestal member 149 is formed to have a larger size than the lower opening 155B of the via hole 155. By forming the pedestal member 149 that is wider in plan view, the slope of the pedestal member 149 can be made smaller (gentle) while maintaining the height H1 of the pedestal member 149. The conductive ink can be prevented from flowing down, and the thickness of the wiring 151 formed on the pedestal member 149 can be prevented from being locally reduced or the occurrence of disconnection.

Next, after forming the resin layer 153, the controller 120 forms an upper layer wiring 159 that is drawn out to the upper surface 153A of the resin layer 153 on a part of the inclined surface 157 of the via hole 155, as shown in FIG. Controller 120 connects wiring 159 to wiring 151 within via hole 155 . Specifically, the controller 120 controls the first printing unit 72 to linearly discharge conductive ink onto the bottom of the via hole 155 and the inclined surface 157 using the inkjet head 76 . The controller 120 discharges conductive ink in accordance with the position of the wiring 151 in the via hole 155 (see FIG. 9). The conductive ink is ejected from the wiring 151 exposed in the via hole 155 to the upper surface 153A of the resin layer 153 via the inclined surface 157.

Note that the controller 120 may remove excess resin on the wiring 151 before forming the upper layer wiring 159. In shaping the resin layer 153, there is a possibility that excess ultraviolet curing resin may adhere to the wiring 151 exposed from the lower opening 155B. Therefore, the controller 120 may remove the excess resin residue on the wiring 151 by emitting a laser or the like toward the wiring 151 exposed from the lower opening 155B of the via hole 155, for example. Thereby, the resistance at the connection portion between the wiring 151 and the wiring 159 can be reduced.

The controller 120 controls the baking section 74 and applies heat from the infrared heater of the irradiation device 78 to the conductive ink ejected from the upper part of the wiring 151 to the upper surface 153A of the resin layer 153. Thereby, the conductive ink can be fired to form the upper layer wiring 159 electrically connected to the lower layer wiring 151. Each lower layer wiring pattern formed on the resin layer 153 and each upper layer wiring pattern can be electrically connected (see FIG. 9). Incidentally, the inclination angle θ2 (see FIG. 7) of the inclined surface 157 of the via hole 155 is, for example, 25 degrees or less. The length of the inclined surface 157 along the direction parallel to the base material 70 is, for example, several hundred μm. Further, the thickness of the resin layer 153 is, for example, 20 to 40 μm.

Here, FIG. 10 shows a cross section of the wirings 151 and 159 and the resin layer 153 of a comparative example. In the circuit board of FIG. 10, the pedestal member 149 is not formed under the lower layer wiring 151. Similarly to the wiring 151 described above, when forming the wiring 159, when conductive ink is discharged onto the slope 157 of the via hole 155, if the slope angle θ2 of the slope 157 is steep, the discharged conductive ink may flow down along the slope 157. As a result, there is a risk that the thickness of the wiring 159 may be locally reduced or a disconnection may occur, reducing the reliability of the connection. Furthermore, in the manufacturing process of FIG. 6 (an example of a resin layer forming process), the controller 120 of this embodiment forms a via hole 155 in the resin layer 153 that penetrates the resin layer 153 and has an inclined surface 157 on the inner wall. In the via hole 155 having such an inclined surface 157, if the inclination angle θ2 is made small in order to suppress the conductive ink from flowing down from the inclined surface 157, if the thickness of the resin layer 153 is constant, the via hole 155 will be The diameter L1 of the upper opening 155A increases inversely as the inclination angle θ2 decreases. The area occupied by the via holes 155 in the resin layer 153 increases, and the wiring density of the wirings 151 and 159 decreases.

Therefore, in the wiring forming method of this embodiment, as shown in FIGS. 4 and 5, first, the pedestal member 149 is formed, and the lower layer wiring 151 is formed on the pedestal member 149. As shown in FIG. 7, the lower layer wiring 151 raised high by the pedestal member 149 and the upper layer wiring 159 are connected below the inclined surface 157. Thereby, by raising the bottom of the wiring 151 using the pedestal member 149, the inclination angle θ2 of the inclined surface 157 can be reduced while suppressing the diameter L1 from increasing (enlargement of the upper opening 155A). In other words, the via hole 155 can be made smaller by shortening the diameter L1. Thereby, the reliability of the connection of the wiring 159 can be improved while reducing the diameter L1 and increasing the wiring density of the wirings 151 and 159.

Further, as shown in FIG. 8, for example, after forming the wiring 159, the controller 120 mounts the electronic component 163 on the wiring 159 on the upper surface 153A of the resin layer 153. Specifically, the controller 120 moves the stage 52 below the third modeling unit 29, for example, after forming the wiring 159. The controller 120 controls the third modeling unit 29 to cause the dispenser 130 to discharge the conductive paste onto the wiring 159.

After discharging the conductive paste, the controller 120 moves the stage 52 below the mounting unit 26 and mounts the electronic component 163 using the mounting section 102 . The mounting head 112 of the mounting section 102 is arranged so that the component terminal 165 of the electronic component 163 is located at the position of the conductive paste. Then, the controller 120 forms the bumps 167 by heating and hardening the conductive paste using the baking section 74 of the first modeling unit 22 . Component terminals 165 of electronic component 163 are electrically connected to wiring 159 via bumps 167. In this manner, the electronic device manufacturing apparatus 10 of this embodiment can form a circuit board (resin layer 153 having wirings 151 and 159) on which electronic components 163 are mounted.

Note that the manufacturing process of the resin layer 153 having the wirings 151 and 159 described above, the structure of the molded object, etc. are merely examples. For example, the controller 120 may fill the via hole 155 with a resin layer (ultraviolet curing resin) after forming the upper layer wiring 159. Then, the controller 120 may further form a resin layer having via holes on the filled resin layer, and form an upper layer wiring to be connected to the wiring 159. In this case, similarly to the wiring 151, a pedestal member 149 may be formed to raise the bottom of the wiring 159. That is, when forming a multilayer substrate, the pedestal member 149 may be appropriately formed in each layer.

Further, in the example shown in FIG. 9, one set of wirings 151 and 159 are connected through one via hole 155, but a plurality of sets of wirings 151 and 159 may be connected through one via hole 155. FIG. 11 shows a state in which multiple sets of wiring lines 151 and 159 are connected through one via hole 155. As shown in FIG. 11, for example, the controller 120 forms a combination of wires 151 and 159 connected within one via hole 155 in a line with a predetermined pitch P1 between them. For example, the controller 120 forms the via hole 155 as a hole (slit shape) whose hole diameter is long in one direction (the left-right direction in FIG. 11). The via hole 155 has a generally rectangular upper opening 155A and a lower opening 155B that are long in one direction in plan view. The pedestal member 149 is formed into a substantially rectangular thin plate shape that is long in the longitudinal direction of the via hole 155 when viewed from above, in accordance with the shape of the via hole 155 . Then, the controller 120 forms a plurality of sets of wiring lines 151 and 159 that are lined up in the longitudinal direction of the via hole 155. Among the plurality of sets of wirings 151 and 159, the three sets at the center are formed in a straight line along one direction (vertical direction in FIG. 11), for example. That is, the upper layer wiring 159 connected to the lower layer wiring 151 is formed along the direction in which the lower layer wiring 151 is pulled out from the via hole 155 . A plurality of wiring lines 159 are arranged on the inclined surface 157 of the via hole 155 along the longitudinal direction of the via hole 155 (the left-right direction in FIG. 11). Further, the plurality of lower layer wirings 151 are arranged side by side on the horizontally long pedestal member 149.

Here, as shown in FIG. 9, if only one set of wirings 151 and 159 is formed in one via hole 155, the pitch P1 ( (see FIG. 9) may increase. On the other hand, as shown in FIG. 11, by forming multiple sets of wirings 151 and 159 together in one via hole 155, the pitch P1 between the wirings 151 and 159 can be made extremely narrow. . This pitch P1 can be narrowed to, for example, several hundred μm or less, although it depends on the accuracy of three-dimensional layered manufacturing (resolution of inkjet method). This makes it possible to extremely increase the wiring density of the wirings 151 and 159.

Furthermore, in the electroless plating method used for manufacturing via holes and through holes in conventional substrate manufacturing, it is common to plate the entire inner wall of the via hole, and as shown in FIG. It is difficult to form wiring on a part of the inner wall. On the other hand, in the electronic device manufacturing apparatus 10 of this embodiment, the wiring 159 can be formed at any position on the inclined surface 157 by using three-dimensional additive manufacturing. In other words, the electronic device manufacturing apparatus 10 of this embodiment can take advantage of the advantages of three-dimensional additive manufacturing to form multiple sets of wiring 151 and 159 within one via hole 155 to increase wiring density. can.

Therefore, the controller 120 of this embodiment may form a pedestal member 149 that is long in one direction, as shown in FIG. Further, the controller 120 forms a plurality of wiring lines 151 arranged in parallel in the longitudinal direction of the pedestal member 149, and forms a resin layer 153 having a long inclined surface 157 in the longitudinal direction of the pedestal member 149. Then, the controller 120 may form a plurality of wires 159 to be connected to each of the plurality of wires 151 arranged on the pedestal member 149.

According to this, a plurality of wirings 151 and 159 are connected through one inclined surface 157 formed in the resin layer 153. Thereby, by forming the pedestal member 149, it is possible to increase the reliability of the connection of the wiring 159 and narrow the pitch P1 between the wirings 151 and 159, thereby increasing the wiring density. The wiring density can be made extremely high compared to the case where only one set of wirings 151 and 159 are formed on one inclined surface 157 shown in FIG. In turn, it is possible to downsize molded objects such as circuit boards.

In addition, when forming a plurality of lower layer wirings 151, the controller 120, in forming the pedestal member 149, arranges the pedestal member 149 so that the ends of the plurality of wirings 151 on the wiring 159 side are at the same height. A surface may also be formed. FIG. 12 is a schematic diagram showing the surface 149A of the pedestal member 149 when a plurality of wirings 151 are formed. As shown in FIG. 12, for example, the controller 120 flattens the surface 149A of the pedestal member 149 using a roller of the flattening device 90 to form a flat surface. The surface 149A is, for example, a plane having the same height H1 (see FIG. 4) from the lower end of the pedestal member 149. Controller 120 forms lower layer wiring 151 at a predetermined pitch on surface 149A of the same height. Then, the controller 120 may form an upper layer wiring 159 (see FIG. 11) so as to be connected to each wiring 151 on the surface 149A. According to this, the pedestal member 149 is formed to have the same height H1 so that the ends of the plurality of wirings 151 on the wiring 159 side have the same height. By connecting multiple sets of wiring 151, 159 at the same height, the plurality of wiring 151, 159 can be modeled together while keeping the inkjet head 76 at the same height. The time required to manufacture a circuit board in which multiple sets of wiring lines 151 and 159 are connected through one via hole 155 can be shortened.

Further, as illustrated by the wirings 151 and 159 at both ends in the left-right direction in FIG. . For example, the outermost pair of wirings 151 may be arranged so as to spread outward. In this way, by changing the direction in which the wirings 151 and 159 are drawn out from one via hole 155, a more flexible wiring pattern can be formed.

Further, the via hole 155 in which the plurality of sets of wirings 151 and 159 are arranged is not limited to a long shape along one direction. As shown in FIG. 13, for example, one via hole 155 may be formed by connecting a plurality of via holes with shifted positions. For example, if the control program 126 is set as design data to form via holes in accordance with the connection positions of a pair of wiring lines 151 and 159, the controller 120 may determine whether the via holes are adjacent to each other by a predetermined distance or less. You may decide whether or not there is one. Then, the controller 120 may connect a plurality of via holes depending on whether the via holes are adjacent to each other at a predetermined distance or less. The inclined surface 157 of the via hole 155 has, for example, a comb-like shape when viewed from above. Thereby, the wirings 151 and 159 can be brought closer to each other by an amount corresponding to the overlap of the plurality of via holes, and the wiring density can be increased.

Further, FIG. 14 shows, as an example, a plan view of a state in which an electronic component 163 is mounted on the upper surface 153A of the resin layer 153. Note that FIG. 14 omits illustration of the resin layer 153. For example, the electronic component 163 is provided with a plurality of component terminals 165 at predetermined intervals along the vertical direction in FIG. The via hole 155 is formed as a long hole in the direction in which the component terminals 165 are lined up. Each wiring 159 drawn out from the via hole 155 is connected to a component terminal 165 via an inclined surface 157, that is, connected to an electronic component 163.

A plurality of component terminals 165 provided on an electronic component 163 such as an IC chip may be arranged side by side in one direction, as shown in FIG. Long via holes 155 may be formed in accordance with the arrangement of component terminals 165, and a plurality of wiring lines 159 may be formed to be drawn out through the via holes 155. Then, each of the plurality of wirings 159 is connected to each of the plurality of component terminals 165. Thereby, the plurality of wirings 159 connected to the electronic component 163 can be formed with high density by three-dimensional additive manufacturing.

Further, the wiring connected to the electronic component 163 is not limited to the wiring 159 connected to the lower layer wiring 151. For example, as shown in FIG. 14, a folded wiring 169 may be formed that once enters the via hole 155, passes over the pedestal member 149, and is folded back (not connected to the wiring 151 in the lower layer). For example, in the process of manufacturing the wiring 159, the controller 120 forms the folded wiring 169 using conductive paste. For example, the folded wiring 169 descends downward from the upper surface 153A of the resin layer 153 via the inclined surface 157, passes through the upper surface of the pedestal member 149, and passes through the inclined surface 157 to the upper surface 153A of the resin layer 153 at another position. This is the wiring that returns to.

Depending on the wiring pattern, there may be a wiring that passes near the wiring 159 or the via hole 155 but does not go down to the layer below where the wiring 151 is formed, but is desired to be disposed on the upper surface 153A of the resin layer 153. On the other hand, if a part of the via hole 155 is filled or a wiring is formed on the filled hole after filling all the via holes 155 just to arrange a wiring that does not go down to the lower layer, the manufacturing process will increase. This causes delays in manufacturing time and increases in manufacturing costs. On the other hand, by forming the folded wiring 169 in the same process as the wiring 159, it is possible to form two types of wiring in one process, thereby reducing manufacturing time and manufacturing cost.

Note that the inclined surface 157 on which the plurality of wiring lines 159 are arranged is not limited to the inner wall of the via hole 155. For example, as shown in FIG. 15, an inclined surface 157 may be formed at the end of the resin layer 153. The inclined surface 157 in FIG. 15 is not the inner wall of the via hole 155 as shown in FIG. 7, but is an end surface formed at the end of the resin layer 153. For example, the controller 120 forms a lower layer wiring 151 and then forms an upper layer wiring 159 along the inclined surface 157 so as to fold it back. The controller 120 may fill the ends of the resin layer 153 with the resin layer 161 after forming the wiring 159. In this case, the controller 120 forms the pedestal member 149 in accordance with the connection position of the wirings 151 and 159 (the position of the inclined surface 157).

Incidentally, in the above embodiment, the wiring 151 is an example of the first wiring. The lower opening 155B is an example of an opening. The wiring 159 is an example of a second wiring. Conductive ink and conductive paste are examples of fluids containing metal particles. The process in FIG. 4 is an example of a pedestal member forming process. The process shown in FIG. 5 is an example of a first wiring forming process. The process shown in FIG. 6 is an example of a resin layer forming process. The process shown in FIG. 7 is an example of the second wiring forming process.

As described above, the present embodiment described above provides the following effects.
In the process of forming the wirings 151 and 159 of this embodiment, a step of forming the pedestal member 149 having a predetermined height H1 from a resin material (see FIG. 4), and a step of forming the pedestal member 149 with a conductive ink on the surface of the pedestal member 149 are performed. (see FIG. 5). Further, the forming process includes a process of forming a resin layer 153 having an inclined surface 157 formed in accordance with the position of the pedestal member 149 (see FIG. 6), and forming a wiring 159 on the inclined surface 157 using conductive ink. and a step of forming the wiring 159 so as to be connected to the wiring 151 on the pedestal member 149 (see FIG. 7).

According to this, by forming the wiring 151 on the pedestal member 149, it is possible to raise the wiring 151 to a predetermined height H1. By bringing the wiring 151 to a higher position, the angle of the slope 157 can be made gentler and the wiring 159 can be connected. When forming the wiring 159, it is possible to suppress the conductive ink from flowing down on the inclined surface 157, and it is possible to form the wiring 159 with a more uniform thickness, thereby suppressing the occurrence of disconnection. The reliability of the connection of the wiring 159 can be improved.

Note that the present disclosure 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 above embodiment, a case was explained in which one layer of wiring 151, 159 is formed, but a plurality of resin layers 153 are stacked to form a plurality of layers of wiring 151, 159 via pedestal member 149 and via hole 155. You can also connect.
Further, the resin layer 153 may be a circuit board on which the electronic component 163 is not mounted.
Furthermore, the pedestal member 149 may have a disk shape with an inner diameter smaller than the lower opening 155B of the via hole 155 in plan view. That is, the pedestal member 149 may have a smaller shape and size than the via hole 155.
Further, in the case of connecting the plurality of wirings 151 shown in FIG. 12, the surface 149A of the pedestal member 149 does not have to be flat. For example, the surface 149A may be formed with an inclined surface, a curved surface, an uneven surface, or the like.
Further, in the above embodiment, an ultraviolet curable resin that is cured by irradiation with ultraviolet light is used, but it is possible to use various curable resins such as a thermosetting resin that is cured by heat.
In addition, the method of three-dimensional additive manufacturing in the present disclosure is not limited to the inkjet method or stereolithography (SL), but other methods such as fused deposition modeling (FDM) may be employed. can.

149 pedestal member, 149A surface, 151 wiring (first wiring), 153 resin layer, 153A top surface, 155 via hole, 155B lower opening (opening), 157 slope, 159 wiring (second wiring), H1 height.

Claims (5)

a pedestal member forming step of forming a pedestal member having a predetermined height from a resin material;
a first wiring forming step of forming a first wiring that connects from a position where the pedestal member is not formed to a surface of the pedestal member so that a part of the wiring is raised by a fluid containing metal particles; ,
A resin layer that covers the pedestal member and the first wiring so that a part of the pedestal member and the first wiring is exposed, the resin layer having an inclined surface formed in accordance with the position of the pedestal member. a resin layer forming step;
forming a second wiring connected to a top surface of the resin layer on a part of the inclined surface using a fluid containing metal particles , and forming the second wiring so as to connect to the first wiring on the pedestal member; a second wiring forming step,
including;
In the resin layer forming step,
A via hole is formed in the resin layer, penetrating the resin layer and having the inclined surface on the inner wall,
The upper surface of the resin layer is
located at a higher position than the surface of the pedestal member,
The inclined surface of the resin layer is
tilting away from the pedestal member from the bottom to the top;
The pedestal member is
A method for forming wiring in a shape that matches the via hole . In the second wiring forming step,
2. The wiring forming method according to claim 1, wherein the second wiring is formed so as to be connected from the upper part of the first wiring to the upper surface of the resin layer along the inclined surface. The pedestal member is
3. The wiring forming method according to claim 1 , wherein the via hole is formed to have a size larger than the size of an opening formed on the bottom side of the via hole when viewed from above. In the pedestal member forming step,
forming the pedestal member that is long in one direction;
In the first wiring forming step,
forming a plurality of the first wirings arranged in line in the longitudinal direction of the pedestal member;
In the resin layer forming step,
forming the inclined surface that is long in the longitudinal direction of the pedestal member;
In the second wiring forming step,
The wiring forming method according to any one of claims 1 to 3, wherein a plurality of said second wirings are formed to be connected to each of said plurality of first wirings arranged on said pedestal member. In the pedestal member forming step,
5. The wiring forming method according to claim 4, wherein the surface of the pedestal member is formed so that the end portions of the plurality of first wirings on the second wiring side have the same height.

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