WO2011040502A1 - Circuit substrate and process for production thereof - Google Patents

Circuit substrate and process for production thereof Download PDF

Info

Publication number
WO2011040502A1
WO2011040502A1 PCT/JP2010/067026 JP2010067026W WO2011040502A1 WO 2011040502 A1 WO2011040502 A1 WO 2011040502A1 JP 2010067026 W JP2010067026 W JP 2010067026W WO 2011040502 A1 WO2011040502 A1 WO 2011040502A1
Authority
WO
WIPO (PCT)
Prior art keywords
circuit board
conductor
connection terminal
connection
metal particles
Prior art date
Application number
PCT/JP2010/067026
Other languages
French (fr)
Japanese (ja)
Inventor
登 加藤
純 佐々木
聡 石野
Original Assignee
株式会社村田製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社村田製作所 filed Critical 株式会社村田製作所
Priority to JP2011534290A priority Critical patent/JP5287991B2/en
Publication of WO2011040502A1 publication Critical patent/WO2011040502A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/321—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/18—Printed circuits structurally associated with non-printed electric components
    • H05K1/182—Printed circuits structurally associated with non-printed electric components associated with components mounted in the printed circuit board, e.g. insert mounted components [IMC]
    • H05K1/185—Components encapsulated in the insulating substrate of the printed circuit or incorporated in internal layers of a multilayer circuit
    • H05K1/186—Components encapsulated in the insulating substrate of the printed circuit or incorporated in internal layers of a multilayer circuit manufactured by mounting on or connecting to patterned circuits before or during embedding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161—Disposition
    • H01L2224/16151—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/16221—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/16225—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/0393—Flexible materials
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/095—Conductive through-holes or vias
    • H05K2201/096—Vertically aligned vias, holes or stacked vias
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/06—Lamination
    • H05K2203/063—Lamination of preperforated insulating layer
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/46—Manufacturing multilayer circuits
    • H05K3/4611—Manufacturing multilayer circuits by laminating two or more circuit boards
    • H05K3/4614—Manufacturing multilayer circuits by laminating two or more circuit boards the electrical connections between the circuit boards being made during lamination
    • H05K3/4617—Manufacturing multilayer circuits by laminating two or more circuit boards the electrical connections between the circuit boards being made during lamination characterized by laminating only or mainly similar single-sided circuit boards
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/46—Manufacturing multilayer circuits
    • H05K3/4611—Manufacturing multilayer circuits by laminating two or more circuit boards
    • H05K3/4626—Manufacturing multilayer circuits by laminating two or more circuit boards characterised by the insulating layers or materials
    • H05K3/4632—Manufacturing multilayer circuits by laminating two or more circuit boards characterised by the insulating layers or materials laminating thermoplastic or uncured resin sheets comprising printed circuits without added adhesive materials between the sheets

Definitions

  • the present invention relates to a circuit board and a method for manufacturing the circuit board, and more particularly to a circuit board including a laminated body in which a plurality of insulator layers made of a flexible material are stacked and a method for manufacturing the circuit board.
  • a printed circuit board described in Patent Document 1 As a conventional circuit board, for example, a printed circuit board described in Patent Document 1 is known.
  • a conductor pattern and a conductive composition are provided in an insulating base material.
  • the insulating base material is configured by laminating a plurality of resin films.
  • the conductor pattern is a conductor layer provided on the resin film.
  • the conductive composition is a via-hole conductor obtained by filling a via hole penetrating a resin film with a conductive paste and sintering it, and is connected to a conductor pattern at one end thereof.
  • the electric element is accommodated in a cavity provided in the insulating base material.
  • the electric element is mounted on the other end of the conductive composition. Thereby, the electric element and the conductor pattern are electrically connected by the conductive composition.
  • the electrical connection between the conductor pattern and the electric element may be cut as described below. More specifically, since the insulating base material is made of a flexible resin film, it can be deformed. On the other hand, since the electric element is a chip-type electronic component, it can hardly be deformed. Therefore, when the insulating base material in which the electric element is incorporated is deformed, a deviation may occur between the electric element and the conductive composition. Since the conductive composition is a via-hole conductor having a dense structure obtained by metallizing the conductive paste, it is relatively hard and hardly deformed. Therefore, the conductive composition may be separated from the electric element. That is, there is a possibility that the electrical connection between the conductor pattern and the electric element is broken.
  • An object of the present invention is to provide an electronic component and an electronic component in a circuit board including a laminated body in which an electronic component is embedded and an insulating layer made of a flexible material is laminated. Is to prevent a disconnection from occurring between the terminal electrode and the electrically connected terminal electrode.
  • a circuit board includes a stacked body in which a plurality of insulating layers made of a flexible material are stacked, a connection terminal provided in the stacked body, and the stacked body. It is characterized by comprising a built-in electronic component, and a connection conductor that electrically connects the electronic component and the connection terminal, and is formed of an aggregate of metal particles.
  • the circuit board manufacturing method includes the steps of preparing the insulator layer provided with the connection terminal, applying the conductive paste made of the metal particles to the connection terminal, and the connection terminal. A step of mounting the electronic component, and a step of laminating the plurality of insulator layers and heating and pressure bonding to obtain a laminate by fusing the plurality of insulator layers together, The insulating layer is heated at a temperature lower than the melting start temperature of the metal particles.
  • the electronic component and the electronic component are electrically connected. Can be prevented from occurring between the terminal electrodes connected to each other.
  • FIG. 1A is a cross-sectional structure diagram of a circuit board according to an embodiment of the present invention.
  • FIG. 1B is an enlarged view of the circuit board. It is an exploded view of the circuit board of FIG. It is sectional structure drawing which showed the manufacturing process of the circuit board. It is sectional structure drawing which showed the manufacturing process of the circuit board. It is an enlarged view of a circuit board concerning a modification.
  • FIG. 1A is a cross-sectional structure diagram of a circuit board 10 according to an embodiment of the present invention.
  • FIG. 1B is an enlarged view of the circuit board 10.
  • FIG. 2 is an exploded view of the circuit board 10 of FIG.
  • the stacking direction of the circuit boards 10 is defined as the z-axis direction
  • the left-right direction of the paper surface of FIG. 1 is defined as the x-axis direction
  • the surface of the flexible sheet 14 refers to a surface located on the positive side in the z-axis direction
  • the back surface of the flexible sheet 14 refers to a surface located on the negative direction side in the z-axis direction.
  • the circuit board 10 includes a laminated body 12, conductor layers 16 (16b to 16g), connection terminals 18, electronic components 20, connection conductors 30, and via-hole conductors b1 to b5.
  • the laminate 12 is formed by laminating a plurality (seven in FIG. 2) of flexible sheets (insulator layers) 14 (14a to 14g), and has a rectangular parallelepiped shape.
  • the laminate 12 can be deformed by an external force.
  • the flexible sheet 14 is made of a flexible material (for example, a thermoplastic resin such as a liquid crystal polymer) and has a rectangular shape.
  • the flexible sheet 14 has a thickness of about 25 ⁇ m to 100 ⁇ m.
  • the flexible sheets 14c and 14d are provided with blank areas B1 and B2 for forming cavities for accommodating electronic components 20 described later.
  • the blank areas B1 and B2 are formed by punching the central portions of the flexible sheets 14c and 14d into a rectangular shape.
  • the blank areas B1 and B2 are formed to be slightly larger than the electronic component 20 when viewed in plan from the z-axis direction.
  • the boundary is not illustrated.
  • the main surface on the positive side in the z-axis direction of the flexible sheet 14 is referred to as a front surface
  • the main surface on the negative direction side in the z-axis direction of the flexible sheet 14 is referred to as a back surface.
  • the conductor layer 16 is provided in the laminate 12 and is a wiring conductor, a coil conductor, a capacitor conductor, or the like. More specifically, the conductor layers 16b to 16f are provided on the surfaces of the flexible sheets 14b to 14f, respectively, and are made of, for example, copper foil.
  • the conductor layer 16g is provided on the back surface of the flexible sheet 14g, and is made of, for example, copper foil. In addition, about the conductor layer 16, in order to avoid that drawing becomes complicated, the referential mark is attached
  • connection terminal 18 is provided in the laminated body 12, and functions as a land on which the electronic component 20 is mounted.
  • the connection terminal 18 is provided on the surface of the flexible sheet 14e, and is made of, for example, copper foil.
  • the via-hole conductors b1 to b5 are provided so as to penetrate the flexible sheets 14b, 14c, and 14e to 14g in the z-axis direction, respectively.
  • the via-hole conductors b1 to b5 are electrically connected to the conductor layer 16 or the connection terminal 18 located on both sides in the z-axis direction. As described above, the conductor layer 16, the connection terminal 18, and the via-hole conductors b1 to b5 are connected to each other to form a circuit.
  • the via-hole conductors b1 to b5 only representative ones are provided with reference numerals in order to avoid complicated drawings.
  • the electronic component 20 is built in the laminate 12 and is a semiconductor chip (active component) such as a radio frequency IC chip for RFID (Radio Frequency IDentification), an IC chip for image processing used in a digital still camera, or Passive components such as chip capacitors and chip resistors.
  • active component such as a radio frequency IC chip for RFID (Radio Frequency IDentification), an IC chip for image processing used in a digital still camera, or Passive components such as chip capacitors and chip resistors.
  • the electronic component 20 includes a substrate 22 and connection terminals 24.
  • the substrate 22 is made of a relatively hard material such as silicon or ceramic and cannot be deformed like the stacked body 12.
  • a semiconductor integrated circuit is formed inside the substrate 22.
  • connection terminal 24 is provided on the main surface of the substrate 22 on the negative side in the z-axis direction, and is electrically connected to the connection terminal 18 when the electronic component 20 is mounted on the connection terminal 18.
  • the connection terminal 24 is made of, for example, Au or Cu.
  • connection conductor 30 electrically connects the electronic component 20 and the connection terminal 18, and more specifically, connects the connection terminal 18 and the connection terminal 24. Yes.
  • connection conductor 30 is comprised by the aggregate
  • the connection conductor 30 is configured by the periphery thereof being hardened by the flexible sheet 14.
  • connection conductor 30 by being held by the flexible sheet 14 melted at the time of crimping so as not to be separated.
  • the connection conductor 30 is not metallized by melting and solidifying metal particles, but is configured by most of the metal particles being solidified while maintaining the state of particles. Therefore, the connection conductor 30 has a relatively fragile structure and can be easily deformed or collapsed by an external force. Note that some metal particles included in the connection conductor 30 may be necked together. It is sufficient that the connecting conductor 30 exhibits flexibility.
  • circuit board manufacturing method below, the manufacturing method of the circuit board 10 is demonstrated, referring drawings.
  • a case where one circuit board 10 is manufactured will be described as an example, but actually, a plurality of circuit boards 10 are simultaneously manufactured by laminating and cutting large-sized flexible sheets.
  • 3 and 4 are cross-sectional structural views showing the manufacturing process of the circuit board 10.
  • the conductor layer 16, the connection terminal 18, and the via-hole conductors b1 to b5 shown in FIG. 2 are formed on the flexible sheets 14b to 14g.
  • the process of forming the conductor layer 16e, the connection terminal 18, and the via-hole conductor b3 on the flexible sheet 14e will be described as an example.
  • a plurality of flexible sheets 14e each having a copper foil 116e having a thickness of 5 ⁇ m to 50 ⁇ m formed on the entire surface is prepared.
  • a via hole h is formed by irradiating a laser beam from the back side to the position where the via hole conductor b3 of the flexible sheet 14e is formed.
  • the via hole h formed in the flexible sheet 14e is filled with a conductive paste mainly composed of an alloy of tin and silver to form a via hole conductor b3.
  • a conductor layer 16e and connection terminals 18 are formed on the surface of the flexible sheet 14e by a photolithography process. Specifically, a resist having the same shape as the conductor layer 16e and the connection terminal 18 is printed on the copper foil 116e of the flexible sheet 14e. And the copper foil 116e of the part which is not covered with the resist is removed by performing an etching process with respect to the copper foil 116e. Thereafter, the resist is removed. Thereby, the conductor layer 16e and the connection terminal 18 are formed on the surface of the flexible sheet 14e. Through the above steps, the flexible sheet 14e provided with the connection terminals 18 is prepared.
  • the conductor layer 16 and the via-hole conductors b1, b2, b4, and b5 shown in FIG. 2 are formed on the flexible sheets 14b to 14d, 14f, and 14g. And since it is the same as the process of forming the via-hole conductor b3, description is abbreviate
  • the conductor layer 16g is provided in the back surface. Therefore, the process of forming the conductor layer 16g on the flexible sheet 14g needs to be performed by inverting the front and back of the process of forming the conductor layer 16e and the connection terminal 18 on the flexible sheet 14e.
  • a conductive material containing metal particles (a single metal containing silver or copper as a main component or an alloy containing silver or copper as a main component) and a resin binder (for example, acrylate or methacrylate).
  • An adhesive paste 130 is applied to the connection terminals 18.
  • the conductive paste 130 include a mixture of 90% by weight of metal particles and 10% by weight of a binder resin.
  • the conductive paint may contain an organic solvent, a dispersant, a plasticizer, and the like.
  • the electronic component 20 is mounted on the connection terminal 18. More specifically, the electronic component 20 is mounted on the flexible sheet 14e so that the connection terminal 18 and the connection terminal 24 match. Thereby, the connection terminal 18 and the connection terminal 24 are fixed via the conductive paste 130. Thereafter, the flexible sheet 14e on which the electronic component 20 is mounted is left for 30 minutes in an environment of a temperature of 150 ° C., for example. Thereby, the electronic component 20 is temporarily fixed on the flexible sheet 14e.
  • the flexible sheets 14a to 14g are laminated so as to be arranged in this order from the positive direction side to the negative direction side in the z-axis direction.
  • the electronic component 20 is accommodated in the cavity B, and a gap exists around the electronic component 20.
  • pressure is applied to the flexible sheets 14a to 14g from both sides in the z-axis direction, and the flexible sheets 14a to 14g are heated.
  • the flexible sheet 14 is heated at a temperature lower than the melting start temperature of the metal particles and higher than the softening / flow starting temperature of the flexible sheet 14.
  • the melting start temperature of the metal particles having an average particle diameter described later is 800 ° C. or higher.
  • the softening / flow start temperature of the flexible sheet 14 is 250 ° C. to 350 ° C. Therefore, in this embodiment, the flexible sheet 14 is heated at a temperature of 300 ° C. for 20 to 60 minutes. Thereby, the main surface of the flexible sheet 14 softens and flows, and the adjacent flexible sheets 14 are firmly joined (fused) to obtain the laminate 12. Further, the softened and fluidized flexible sheet 14 fills the cavity B around the electronic component 20. Further, the resin binder in the conductive paste 130 is almost lost by heating, and the metal particles are held by the softened and fluidized flexible sheet 14. As a result, the connection conductor 30 made of metal particles is formed.
  • the circuit board 10 shown in FIG. 1 is obtained through the above steps.
  • the circuit board 10 can suppress occurrence of disconnection between the connection terminal 18 and the electronic component 20 as described below. More specifically, in the printed circuit board described in Patent Document 1, since the insulating base material is made of a flexible resin film, it can be deformed. On the other hand, since the electric element is a chip-type electronic component, it can hardly be deformed. Therefore, when the insulating base material in which the electric element is incorporated is deformed, a deviation may occur between the electric element and the conductive composition. Since the conductive composition is a via-hole conductor having a dense structure obtained by metallizing a conductive paste, it is relatively hard and hardly deformed. Therefore, the conductive composition may be separated from the electric element. That is, there is a possibility that the electrical connection between the conductor pattern and the electric element is broken.
  • connection terminal 18 and the electronic component 20 are connected by a connection conductor 30 made of an aggregate of metal particles.
  • the connection conductor 30 made of an aggregate of metal particles can be deformed or broken relatively easily by an external force. Therefore, even if the connection terminal 18 and the connection terminal 24 of the electronic component 20 are displaced due to the deformation of the multilayer body 12, the connection conductor 30 is deformed so that the connection state between the connection terminal 18 and the connection terminal 24 is changed. Can be maintained. As a result, the circuit board 10 can suppress the occurrence of disconnection between the connection terminal 18 and the electronic component 20 as described below.
  • connection conductor 30 may become brittle or a sufficient electrical connection may not be obtained depending on the type of metal constituting the connection terminal 18 of the electronic component.
  • connection state between the connection terminal 18 and the connection terminal 24 can be maintained without depending on the type of metal constituting the connection terminal 18 of the electronic component.
  • connection conductor 30 is solidified by the flexible sheet 14, and the shape is maintained. Therefore, even if the metal particles of the connection conductor 30 are broken by an external force, they are not separated from each other. That is, even if the laminated body 12 is deformed, the metal particles of the connection conductor 30 can maintain conductivity due to the form of the aggregate and the contact between the metal particles.
  • the metal particles of the connecting conductor 30 have an average particle diameter (D50) of 0.5 ⁇ m or more and 30 ⁇ m or less.
  • D50 average particle diameter
  • the metal particles of the connecting conductor 30 have an average particle diameter (D50) of 0.5 ⁇ m or more and 30 ⁇ m or less.
  • connection terminal 24 is made of Au
  • the metal particles of the connection conductor 30 are made of a single metal or alloy mainly composed of Ag or Cu.
  • the material of the metal particles is harder than the material of the connection terminals 24.
  • the metal particles are reduced to the connection terminals 24 when the flexible sheet 14 is crimped. As a result, the connection conductor 30 and the connection terminal 24 are more reliably connected.
  • the cavity B is formed slightly larger than the electronic component 20, the electronic component 20 is prevented from being displaced from the connection terminal 18 by being pressed by the flexible sheet 14 during lamination / crimping.
  • FIG. 5 is an enlarged view of the circuit board 10 according to the modification.
  • FIG. 5 corresponds to the enlarged view of FIG.
  • connection conductor 30 is provided so as to cover not only the main surface on the positive direction side in the z-axis direction but also the side surface of the connection terminal 18, as shown in FIG.
  • the connection terminal 18 and the connection conductor 30 can be electrically connected more reliably.
  • the conductive paste 130 is applied so as to cover the entire connection conductor 18. As a result, the connection conductor 18 is not exposed to air and is not easily oxidized.
  • the flexible sheet 14 In the circuit board 10, in order to form the cavity B for accommodating the electronic component 20, a part of the flexible sheet 14 is punched to form the blank areas B1 and B2.
  • the flexible sheet 14 may be able to absorb a step due to the electronic component 20 due to its flexibility. Therefore, in this case, it is not necessary to form the blank areas B1 and B2 in the flexible sheet 14.
  • the flexible sheets 14c and 14d may be embedded in the electronic component 20 by utilizing the softening and flow of the flexible sheets 14c and 14d without providing the blank areas B1 and B2.
  • the binder resin disappears when the flexible sheet 14 is heated. This disappearance includes not only burning but also disappearing by decomposition. That is, the binder resin is made of a material that is burned down or decomposed by heating the flexible sheet 14. Further, it is desirable that all the binder resin is completely burned out, but it may remain to the extent that the movement of the metal particles is not hindered.
  • the present invention is useful for a circuit board and a method for manufacturing the circuit board, and in particular, a laminated body in which an electronic component is built, and a laminated body in which an insulating layer made of a flexible material is laminated.
  • the circuit board provided with the body is excellent in that it is possible to suppress the occurrence of disconnection between the electronic component and the terminal electrode to which the electronic component is electrically connected.
  • Circuit board 12 Laminated body 14a to 14g Flexible sheet 16b to 16g Conductor layer 18, 24 Connection terminal 20 Electronic component 22 Substrate 30 Connection conductor

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Production Of Multi-Layered Print Wiring Board (AREA)

Abstract

Provided is a circuit substrate comprising a laminate containing a built-in electronic part, the laminate being formed by stacking insulation films of a flexible material, which will not cause circuit disconnection between the electronic part and the electrically connected terminal electrode. The laminate (12) is constituted of a stack of flexible sheets of a flexible material. The connection terminals (18) are provided in the laminate (12). The electronic part (20) is built into the laminate (12). The connecting conductor (30) which connects the electronic part (20) electrically with the connecting terminals (18) is constituted of an assemblage of metal particles.

Description

回路基板及びその製造方法Circuit board and manufacturing method thereof
　本発明は、回路基板及びその製造方法に関し、より特定的には、可撓性材料からなる複数の絶縁体層が積層されてなる積層体を備えた回路基板及びその製造方法に関する。 The present invention relates to a circuit board and a method for manufacturing the circuit board, and more particularly to a circuit board including a laminated body in which a plurality of insulator layers made of a flexible material are stacked and a method for manufacturing the circuit board.
　従来の回路基板としては、例えば、特許文献１に記載のプリント基板が知られている。該プリント基板では、導体パターン及び導電性組成物が絶縁基材内に設けられている。絶縁基材は、複数の樹脂フィルムが積層されて構成されている。導体パターンは、樹脂フィルム上に設けられている導体層である。導電性組成物は、樹脂フィルムを貫通するビアホールに導電ペーストを充填して焼結させて得られたビアホール導体であり、その一端において導体パターンに接続されている。 As a conventional circuit board, for example, a printed circuit board described in Patent Document 1 is known. In the printed circuit board, a conductor pattern and a conductive composition are provided in an insulating base material. The insulating base material is configured by laminating a plurality of resin films. The conductor pattern is a conductor layer provided on the resin film. The conductive composition is a via-hole conductor obtained by filling a via hole penetrating a resin film with a conductive paste and sintering it, and is connected to a conductor pattern at one end thereof.
　更に、回路基板では、絶縁基材内に設けられている空洞内に電気素子が収容されている。電気素子は、導電性組成物の他端上に実装されている。これにより、電気素子と導体パターンとは、導電性組成物により電気的に接続されている。 Furthermore, in the circuit board, the electric element is accommodated in a cavity provided in the insulating base material. The electric element is mounted on the other end of the conductive composition. Thereby, the electric element and the conductor pattern are electrically connected by the conductive composition.
　ところで、特許文献１に記載のプリント基板では、以下に説明するように、絶縁基材を変形させた際に、導体パターンと電気素子との間の電気的な接続が切れてしまうおそれがある。より詳細には、絶縁基材は、可撓性を有する樹脂フィルムにより構成されているので、変形することができる。一方、電気素子は、チップ型の電子部品であるので殆ど変形することができない。よって、電気素子が内蔵された絶縁基材が変形させられた場合には、電気素子と導電性組成物との間にずれが生じることがある。導電性組成物は、導電性ペーストを金属化して得られた緻密な構造を有するビアホール導体であるので、比較的に硬く変形しにくい。そのため、導電性組成物は、電気素子から離れてしまうおそれがある。すなわち、導体パターンと電気素子との間の電気的な接続が切れてしまうおそれがある。 By the way, in the printed circuit board described in Patent Document 1, when the insulating base material is deformed, the electrical connection between the conductor pattern and the electric element may be cut as described below. More specifically, since the insulating base material is made of a flexible resin film, it can be deformed. On the other hand, since the electric element is a chip-type electronic component, it can hardly be deformed. Therefore, when the insulating base material in which the electric element is incorporated is deformed, a deviation may occur between the electric element and the conductive composition. Since the conductive composition is a via-hole conductor having a dense structure obtained by metallizing the conductive paste, it is relatively hard and hardly deformed. Therefore, the conductive composition may be separated from the electric element. That is, there is a possibility that the electrical connection between the conductor pattern and the electric element is broken.
特許第３８６７５９３号公報Japanese Patent No. 3867593
　そこで、本発明の目的は、電子部品を内蔵している積層体であって、可撓性材料からなる絶縁体層が積層されてなる積層体を備えた回路基板において、電子部品と該電子部品が電気的に接続されている端子電極との間において断線が発生することを抑制することである。 SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic component and an electronic component in a circuit board including a laminated body in which an electronic component is embedded and an insulating layer made of a flexible material is laminated. Is to prevent a disconnection from occurring between the terminal electrode and the electrically connected terminal electrode.
　本発明の一形態に係る回路基板は、可撓性材料からなる複数の絶縁体層が積層されて構成されている積層体と、前記積層体に設けられている接続端子と、前記積層体に内蔵されている電子部品と、前記電子部品と前記接続端子とを電気的に接続する接続導体であって、金属粒子の集合体からなる接続導体と、を備えていること、を特徴とする。 A circuit board according to an embodiment of the present invention includes a stacked body in which a plurality of insulating layers made of a flexible material are stacked, a connection terminal provided in the stacked body, and the stacked body. It is characterized by comprising a built-in electronic component, and a connection conductor that electrically connects the electronic component and the connection terminal, and is formed of an aggregate of metal particles.
　また、前記回路基板の製造方法は、前記接続端子が設けられた前記絶縁体層を準備する工程と、前記金属粒子からなる導電性ペーストを、前記接続端子に塗布する工程と、前記接続端子に前記電子部品を実装する工程と、前記複数の絶縁体層を積層して加熱及び圧着することによって、該複数の絶縁体層同士を融着させて前記積層体を得る工程と、を備え、前記絶縁体層の加熱を、前記金属粒子の溶融開始温度よりも低い温度で行うこと、を特徴とする。 The circuit board manufacturing method includes the steps of preparing the insulator layer provided with the connection terminal, applying the conductive paste made of the metal particles to the connection terminal, and the connection terminal. A step of mounting the electronic component, and a step of laminating the plurality of insulator layers and heating and pressure bonding to obtain a laminate by fusing the plurality of insulator layers together, The insulating layer is heated at a temperature lower than the melting start temperature of the metal particles.
　本発明によれば、電子部品を内蔵している積層体であって、可撓性材料からなる絶縁体層が積層されてなる積層体を備えた回路基板において、電子部品と該電子部品が電気的に接続されている端子電極との間において断線が発生することを抑制できる。 According to the present invention, in a circuit board including a multilayer body in which an electronic component is embedded and an insulating layer made of a flexible material is laminated, the electronic component and the electronic component are electrically connected. Can be prevented from occurring between the terminal electrodes connected to each other.
図１（ａ）は、本発明の一実施形態に係る回路基板の断面構造図である。図１（ｂ）は、回路基板の拡大図である。FIG. 1A is a cross-sectional structure diagram of a circuit board according to an embodiment of the present invention. FIG. 1B is an enlarged view of the circuit board. 図１の回路基板の分解図である。It is an exploded view of the circuit board of FIG. 回路基板の製造工程を示した断面構造図である。It is sectional structure drawing which showed the manufacturing process of the circuit board. 回路基板の製造工程を示した断面構造図である。It is sectional structure drawing which showed the manufacturing process of the circuit board. 変形例に係る回路基板の拡大図である。It is an enlarged view of a circuit board concerning a modification.
　以下に、本発明の実施形態に係る回路基板及びその製造方法について図面を参照しながら説明する。 Hereinafter, a circuit board and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the drawings.
（回路基板の構成）
　以下に、本発明の一実施形態に係る回路基板の構成について図面を参照しながら説明する。図１（ａ）は、本発明の一実施形態に係る回路基板１０の断面構造図である。図１（ｂ）は、回路基板１０の拡大図である。図２は、図１の回路基板１０の分解図である。以下では、回路基板１０の積層方向をｚ軸方向と定義し、図１の紙面の左右方向をｘ軸方向と定義し、図１の紙面の垂直方向をｙ軸方向と定義する。また、フレキシブルシート１４の表面とは、ｚ軸方向の正方向側に位置する面を指し、フレキシブルシート１４の裏面とは、ｚ軸方向の負方向側に位置する面を指す。 (Configuration of circuit board)
The configuration of a circuit board according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a cross-sectional structure diagram of a circuit board 10 according to an embodiment of the present invention. FIG. 1B is an enlarged view of the circuit board 10. FIG. 2 is an exploded view of the circuit board 10 of FIG. In the following, the stacking direction of the circuit boards 10 is defined as the z-axis direction, the left-right direction of the paper surface of FIG. 1 is defined as the x-axis direction, and the vertical direction of the paper surface of FIG. Moreover, the surface of the flexible sheet 14 refers to a surface located on the positive side in the z-axis direction, and the back surface of the flexible sheet 14 refers to a surface located on the negative direction side in the z-axis direction.
　回路基板１０は、図１（ａ）に示すように、積層体１２、導体層１６（１６ｂ～１６ｇ）、接続端子１８、電子部品２０、接続導体３０及びビアホール導体ｂ１～ｂ５を備えている。 As shown in FIG. 1A, the circuit board 10 includes a laminated body 12, conductor layers 16 (16b to 16g), connection terminals 18, electronic components 20, connection conductors 30, and via-hole conductors b1 to b5.
　積層体１２は、図２に示すように、複数（図２では７枚）のフレキシブルシート（絶縁体層）１４（１４ａ～１４ｇ）が積層されて構成され、直方体状をなしている。積層体１２は、外力により変形することができる。 As shown in FIG. 2, the laminate 12 is formed by laminating a plurality (seven in FIG. 2) of flexible sheets (insulator layers) 14 (14a to 14g), and has a rectangular parallelepiped shape. The laminate 12 can be deformed by an external force.
　フレキシブルシート１４は、可撓性材料（例えば、液晶ポリマー等の熱可塑性樹脂）からなり、長方形状をなしている。また、フレキシブルシート１４の厚みは、２５μｍ～１００μｍ程度である。フレキシブルシート１４ｃ，１４ｄには、図２に示すように、後述する電子部品２０を収容するための空洞を形成するための空白領域Ｂ１，Ｂ２が設けられている。空白領域Ｂ１，Ｂ２は、フレキシブルシート１４ｃ，１４ｄの中央部分を長方形状に打ち抜いて形成されている。空白領域Ｂ１，Ｂ２は、ｚ軸方向から平面視したときに、電子部品２０よりも僅かに大きくなるように形成されている。なお、図１では、各フレキシブルシート１４の主面同士が密接に接合しているので、その境界を図示していない。また、以下では、フレキシブルシート１４のｚ軸方向の正方向側の主面を表面と称し、フレキシブルシート１４のｚ軸方向の負方向側の主面を裏面と称す。 The flexible sheet 14 is made of a flexible material (for example, a thermoplastic resin such as a liquid crystal polymer) and has a rectangular shape. The flexible sheet 14 has a thickness of about 25 μm to 100 μm. As shown in FIG. 2, the flexible sheets 14c and 14d are provided with blank areas B1 and B2 for forming cavities for accommodating electronic components 20 described later. The blank areas B1 and B2 are formed by punching the central portions of the flexible sheets 14c and 14d into a rectangular shape. The blank areas B1 and B2 are formed to be slightly larger than the electronic component 20 when viewed in plan from the z-axis direction. In addition, in FIG. 1, since the main surfaces of each flexible sheet | seat 14 are closely joined, the boundary is not illustrated. Hereinafter, the main surface on the positive side in the z-axis direction of the flexible sheet 14 is referred to as a front surface, and the main surface on the negative direction side in the z-axis direction of the flexible sheet 14 is referred to as a back surface.
　導体層１６は、図２に示すように、積層体１２内に設けられており、配線導体、コイル導体又はコンデンサ導体等である。より詳細には、導体層１６ｂ～１６ｆはそれぞれ、フレキシブルシート１４ｂ～１４ｆの表面に設けられており、例えば、銅箔により作製されている。また、導体層１６ｇは、フレキシブルシート１４ｇの裏面に設けられており、例えば、銅箔により作製されている。なお、導体層１６については、図面が煩雑になることを避けるために、代表的なものにのみ参照符号を付してある。 As shown in FIG. 2, the conductor layer 16 is provided in the laminate 12 and is a wiring conductor, a coil conductor, a capacitor conductor, or the like. More specifically, the conductor layers 16b to 16f are provided on the surfaces of the flexible sheets 14b to 14f, respectively, and are made of, for example, copper foil. The conductor layer 16g is provided on the back surface of the flexible sheet 14g, and is made of, for example, copper foil. In addition, about the conductor layer 16, in order to avoid that drawing becomes complicated, the referential mark is attached | subjected only to the typical thing.
　接続端子１８は、図２に示すように、積層体１２内に設けられており、電子部品２０が実装されるランドとして機能する。接続端子１８は、フレキシブルシート１４ｅの表面に設けられており、例えば、銅箔により作製されている。 As shown in FIG. 2, the connection terminal 18 is provided in the laminated body 12, and functions as a land on which the electronic component 20 is mounted. The connection terminal 18 is provided on the surface of the flexible sheet 14e, and is made of, for example, copper foil.
　ビアホール導体ｂ１～ｂ５はそれぞれ、フレキシブルシート１４ｂ，１４ｃ，１４ｅ～１４ｇをｚ軸方向に貫通するように設けられている。ビアホール導体ｂ１～ｂ５は、ｚ軸方向の両側に位置する導体層１６又は接続端子１８を電気的に接続している。以上のように、導体層１６、接続端子１８及びビアホール導体ｂ１～ｂ５は、互いに接続されることにより、回路を構成している。なお、ビアホール導体ｂ１～ｂ５については、図面が煩雑になることを避けるために、代表的なものにのみ参照符号を付してある。 The via-hole conductors b1 to b5 are provided so as to penetrate the flexible sheets 14b, 14c, and 14e to 14g in the z-axis direction, respectively. The via-hole conductors b1 to b5 are electrically connected to the conductor layer 16 or the connection terminal 18 located on both sides in the z-axis direction. As described above, the conductor layer 16, the connection terminal 18, and the via-hole conductors b1 to b5 are connected to each other to form a circuit. For the via-hole conductors b1 to b5, only representative ones are provided with reference numerals in order to avoid complicated drawings.
　電子部品２０は、積層体１２に内蔵されており、ＲＦＩＤ（Ｒａｄｉｏ　Ｆｒｅｑｕｅｎｃｙ　ＩＤｅｎｔｉｆｉｃａｔｉｏｎ）用の無線ＩＣチップや、デジタルスチルカメラに用いられる画像処理用のＩＣチップ等の半導体チップ（能動部品）、或いは、チップコンデンサやチップ抵抗などの受動部品である。電子部品２０は、図１及び図２に示すように、基板２２及び接続端子２４を備えている。基板２２は、シリコンやセラミックのような比較的に硬い材料により構成されており、積層体１２のように変形することができない。また、電子部品２０が例えば半導体チップである場合、基板２２の内部には半導体集積回路が形成されている。接続端子２４は、基板２２のｚ軸方向の負方向側の主面に設けられており、電子部品２０が接続端子１８に実装される際に、該接続端子１８と電気的に接続される。接続端子２４は、例えば、ＡｕやＣｕ等により作製されている。 The electronic component 20 is built in the laminate 12 and is a semiconductor chip (active component) such as a radio frequency IC chip for RFID (Radio Frequency IDentification), an IC chip for image processing used in a digital still camera, or Passive components such as chip capacitors and chip resistors. As shown in FIGS. 1 and 2, the electronic component 20 includes a substrate 22 and connection terminals 24. The substrate 22 is made of a relatively hard material such as silicon or ceramic and cannot be deformed like the stacked body 12. When the electronic component 20 is a semiconductor chip, for example, a semiconductor integrated circuit is formed inside the substrate 22. The connection terminal 24 is provided on the main surface of the substrate 22 on the negative side in the z-axis direction, and is electrically connected to the connection terminal 18 when the electronic component 20 is mounted on the connection terminal 18. The connection terminal 24 is made of, for example, Au or Cu.
　接続導体３０は、図１（ａ）に示すように、電子部品２０と接続端子１８とを電気的に接続しており、より具体的には、接続端子１８と接続端子２４とを接続している。そして、接続導体３０は、図１（ｂ）に示すように、無数の金属粒子の集合体により構成されている。より詳細には、金属粒子は、比較的に融点が高い金属（例えば、銀又は銅を主成分とする単体金属或いは銀又は銅を主成分とする合金）を主成分としており、かつ、０．５μｍ以上３０μｍ以下の平均粒径（Ｄ５０）を有している。そして、接続導体３０は、フレキシブルシート１４により周囲を固められることにより構成されている。すなわち、無数の金属粒子は、離れ離れにならないように、圧着時に溶融したフレキシブルシート１４により保持されることにより接続導体３０を構成している。ただし、接続導体３０は、金属粒子同士が溶融して強固に固められて金属化されているのではなく、金属粒子の殆どが粒子の状態を維持した状態で固められて構成されている。よって、接続導体３０は、比較的に脆い構造をなしており、外力により容易に変形又は崩れることができる。なお接続導体３０に含まれる一部の金属粒子同士がネッキングしていてもよい。接続導体３０として可撓性を発現していればよい。 As shown in FIG. 1A, the connection conductor 30 electrically connects the electronic component 20 and the connection terminal 18, and more specifically, connects the connection terminal 18 and the connection terminal 24. Yes. And the connection conductor 30 is comprised by the aggregate | assembly of a countless metal particle, as shown in FIG.1 (b). More specifically, the metal particles are mainly composed of a metal having a relatively high melting point (for example, a simple metal mainly composed of silver or copper, or an alloy composed mainly of silver or copper), and 0. It has an average particle diameter (D50) of 5 μm or more and 30 μm or less. The connection conductor 30 is configured by the periphery thereof being hardened by the flexible sheet 14. That is, the countless metal particles constitute the connection conductor 30 by being held by the flexible sheet 14 melted at the time of crimping so as not to be separated. However, the connection conductor 30 is not metallized by melting and solidifying metal particles, but is configured by most of the metal particles being solidified while maintaining the state of particles. Therefore, the connection conductor 30 has a relatively fragile structure and can be easily deformed or collapsed by an external force. Note that some metal particles included in the connection conductor 30 may be necked together. It is sufficient that the connecting conductor 30 exhibits flexibility.
（回路基板の製造方法）
　以下に、回路基板１０の製造方法について図面を参照しながら説明する。以下では、一つの回路基板１０が作製される場合を例にとって説明するが、実際には、大判のフレキシブルシートが積層及びカットされることにより、同時に複数の回路基板１０が作製される。図３及び図４は、回路基板１０の製造工程を示した断面構造図である。 (Circuit board manufacturing method)
Below, the manufacturing method of the circuit board 10 is demonstrated, referring drawings. Hereinafter, a case where one circuit board 10 is manufactured will be described as an example, but actually, a plurality of circuit boards 10 are simultaneously manufactured by laminating and cutting large-sized flexible sheets. 3 and 4 are cross-sectional structural views showing the manufacturing process of the circuit board 10.
　まず、フレキシブルシート１４ｂ～１４ｇに対して、図２に示す導体層１６、接続端子１８及びビアホール導体ｂ１～ｂ５を形成する。以下では、フレキシブルシート１４ｅに導体層１６ｅ、接続端子１８及びビアホール導体ｂ３を形成する工程を例にとって説明する。 First, the conductor layer 16, the connection terminal 18, and the via-hole conductors b1 to b5 shown in FIG. 2 are formed on the flexible sheets 14b to 14g. Below, the process of forming the conductor layer 16e, the connection terminal 18, and the via-hole conductor b3 on the flexible sheet 14e will be described as an example.
　図３（ａ）に示すように、厚さが５μｍ～５０μｍの銅箔１１６ｅが表面の全面に形成された複数のフレキシブルシート１４ｅを準備する。 As shown in FIG. 3A, a plurality of flexible sheets 14e each having a copper foil 116e having a thickness of 5 μm to 50 μm formed on the entire surface is prepared.
　次に、図３（ｂ）に示すように、フレキシブルシート１４ｅのビアホール導体ｂ３が形成される位置に対して、裏面側からレーザービームを照射して、ビアホールｈを形成する。 Next, as shown in FIG. 3 (b), a via hole h is formed by irradiating a laser beam from the back side to the position where the via hole conductor b3 of the flexible sheet 14e is formed.
　次に、図３（ｃ）に示すように、フレキシブルシート１４ｅに形成したビアホールｈに対して、錫及び銀の合金を主成分とする導電性ペーストを充填し、ビアホール導体ｂ３を形成する。 Next, as shown in FIG. 3C, the via hole h formed in the flexible sheet 14e is filled with a conductive paste mainly composed of an alloy of tin and silver to form a via hole conductor b3.
　次に、図３（ｄ）に示すように、フォトリソグラフィ工程により、導体層１６ｅ及び接続端子１８をフレキシブルシート１４ｅの表面に形成する。具体的には、フレキシブルシート１４ｅの銅箔１１６ｅ上に、導体層１６ｅ及び接続端子１８と同じ形状のレジストを印刷する。そして、銅箔１１６ｅに対してエッチング処理を施すことにより、レジストにより覆われていない部分の銅箔１１６ｅを除去する。その後、レジストを除去する。これにより、導体層１６ｅ及び接続端子１８がフレキシブルシート１４ｅの表面に形成される。以上の工程により、接続端子１８が設けられたフレキシブルシート１４ｅが準備される。 Next, as shown in FIG. 3D, a conductor layer 16e and connection terminals 18 are formed on the surface of the flexible sheet 14e by a photolithography process. Specifically, a resist having the same shape as the conductor layer 16e and the connection terminal 18 is printed on the copper foil 116e of the flexible sheet 14e. And the copper foil 116e of the part which is not covered with the resist is removed by performing an etching process with respect to the copper foil 116e. Thereafter, the resist is removed. Thereby, the conductor layer 16e and the connection terminal 18 are formed on the surface of the flexible sheet 14e. Through the above steps, the flexible sheet 14e provided with the connection terminals 18 is prepared.
　なお、フレキシブルシート１４ｂ～１４ｄ，１４ｆ，１４ｇに対して、図２に示す導体層１６及びビアホール導体ｂ１，ｂ２，ｂ４，ｂ５を形成する工程については、フレキシブルシート１４ｅに導体層１６ｅ、接続端子１８及びビアホール導体ｂ３を形成する工程と同じであるので説明を省略する。ただし、フレキシブルシート１４ｇについては、その裏面に導体層１６ｇが設けられている。そのため、フレキシブルシート１４ｇに導体層１６ｇを形成する工程については、フレキシブルシート１４ｅに導体層１６ｅ及び接続端子１８を形成する工程の表裏を反転させて行う必要がある。 Note that the conductor layer 16 and the via-hole conductors b1, b2, b4, and b5 shown in FIG. 2 are formed on the flexible sheets 14b to 14d, 14f, and 14g. And since it is the same as the process of forming the via-hole conductor b3, description is abbreviate | omitted. However, about the flexible sheet 14g, the conductor layer 16g is provided in the back surface. Therefore, the process of forming the conductor layer 16g on the flexible sheet 14g needs to be performed by inverting the front and back of the process of forming the conductor layer 16e and the connection terminal 18 on the flexible sheet 14e.
　次に、図３（ｅ）に示すように、金属粒子（銀又は銅を主成分とする単体金属或いは銀又は銅を主成分とする合金）及び樹脂バインダ（例えば、アクリレート又はメタクリレート）を含む導電性ペースト１３０を接続端子１８に塗布する。導電性ペースト１３０としては、例えば、金属粒子を９０重量％、バインダ樹脂を１０重量％の割合で混合したものが挙げられる。なお導電ペイントは、有機溶剤、分散剤、可塑剤などを含んでいてもよい。 Next, as shown in FIG. 3 (e), a conductive material containing metal particles (a single metal containing silver or copper as a main component or an alloy containing silver or copper as a main component) and a resin binder (for example, acrylate or methacrylate). An adhesive paste 130 is applied to the connection terminals 18. Examples of the conductive paste 130 include a mixture of 90% by weight of metal particles and 10% by weight of a binder resin. The conductive paint may contain an organic solvent, a dispersant, a plasticizer, and the like.
　次に、図３（ｆ）に示すように、接続端子１８に電子部品２０を実装する。より詳細には、接続端子１８と接続端子２４とが一致するように、フレキシブルシート１４ｅ上に電子部品２０を実装する。これにより、接続端子１８と接続端子２４とは、導電性ペースト１３０を介して固定される。この後、電子部品２０が実装されたフレキシブルシート１４ｅを例えば１５０℃の温度の環境下で、３０分間放置する。これにより、電子部品２０がフレキシブルシート１４ｅ上に仮固定される。 Next, as shown in FIG. 3 (f), the electronic component 20 is mounted on the connection terminal 18. More specifically, the electronic component 20 is mounted on the flexible sheet 14e so that the connection terminal 18 and the connection terminal 24 match. Thereby, the connection terminal 18 and the connection terminal 24 are fixed via the conductive paste 130. Thereafter, the flexible sheet 14e on which the electronic component 20 is mounted is left for 30 minutes in an environment of a temperature of 150 ° C., for example. Thereby, the electronic component 20 is temporarily fixed on the flexible sheet 14e.
　次に、図４に示すように、フレキシブルシート１４ａ～１４ｇをｚ軸方向の正方向側から負方向側へとこの順に並ぶように積層する。この際、図４に示すように、電子部品２０は、空洞Ｂ内に収容され、電子部品２０の周囲には隙間が存在している。そして、フレキシブルシート１４ａ～１４ｇに対してｚ軸方向の両側から圧力を加えると共に、フレキシブルシート１４ａ～１４ｇに対して加熱を施す。この際、金属粒子の溶融開始温度よりも低い温度であって、かつ、フレキシブルシート１４の軟化・流動開始温度よりも高い温度でフレキシブルシート１４の加熱を行う。具体的には、金属粒子が銀又は銅を主成分としている場合には、後述する平均粒径を有する金属粒子の溶融開始温度は、８００℃以上である。また、フレキシブルシート１４の軟化・流動開始温度は、２５０℃～３５０℃ある。そこで、本実施形態では、３００℃の温度で２０分間から６０分間、フレキシブルシート１４を加熱する。これにより、フレキシブルシート１４の主面が軟化・流動し、隣接するフレキシブルシート１４同士が強固に接合（融着）して、積層体１２が得られる。更に、軟化・流動したフレキシブルシート１４は、電子部品２０の周囲の空洞Ｂを埋める。また、導電性ペースト１３０中の樹脂バインダが加熱により殆ど消失し、金属粒子は軟化・流動したフレキシブルシート１４により保持される。その結果、金属粒子からなる接続導体３０が形成される。以上の工程を経て、図１に示す回路基板１０が得られる。 Next, as shown in FIG. 4, the flexible sheets 14a to 14g are laminated so as to be arranged in this order from the positive direction side to the negative direction side in the z-axis direction. At this time, as shown in FIG. 4, the electronic component 20 is accommodated in the cavity B, and a gap exists around the electronic component 20. Then, pressure is applied to the flexible sheets 14a to 14g from both sides in the z-axis direction, and the flexible sheets 14a to 14g are heated. At this time, the flexible sheet 14 is heated at a temperature lower than the melting start temperature of the metal particles and higher than the softening / flow starting temperature of the flexible sheet 14. Specifically, when the metal particles are mainly composed of silver or copper, the melting start temperature of the metal particles having an average particle diameter described later is 800 ° C. or higher. The softening / flow start temperature of the flexible sheet 14 is 250 ° C. to 350 ° C. Therefore, in this embodiment, the flexible sheet 14 is heated at a temperature of 300 ° C. for 20 to 60 minutes. Thereby, the main surface of the flexible sheet 14 softens and flows, and the adjacent flexible sheets 14 are firmly joined (fused) to obtain the laminate 12. Further, the softened and fluidized flexible sheet 14 fills the cavity B around the electronic component 20. Further, the resin binder in the conductive paste 130 is almost lost by heating, and the metal particles are held by the softened and fluidized flexible sheet 14. As a result, the connection conductor 30 made of metal particles is formed. The circuit board 10 shown in FIG. 1 is obtained through the above steps.
（効果）
　回路基板１０は、以下に説明するように、接続端子１８と電子部品２０との間において断線が発生することを抑制できる。より詳細には、特許文献１に記載のプリント基板では、絶縁基材は、可撓性を有する樹脂フィルムにより構成されているので、変形することができる。一方、電気素子は、チップ型の電子部品であるので殆ど変形することができない。よって、電気素子が内蔵された絶縁基材が変形させられた場合には、電気素子と導電性組成物との間にずれが生じることがある。導電性組成物は、導電性ペーストを金属化して得られた緻密な構造を有するビアホール導体であるので、比較的に硬く変形しにくい。そのため、導電性組成物は、電気素子から離れてしまうおそれがある。すなわち、導体パターンと電気素子との間の電気的な接続が切れてしまうおそれがある。 (effect)
The circuit board 10 can suppress occurrence of disconnection between the connection terminal 18 and the electronic component 20 as described below. More specifically, in the printed circuit board described in Patent Document 1, since the insulating base material is made of a flexible resin film, it can be deformed. On the other hand, since the electric element is a chip-type electronic component, it can hardly be deformed. Therefore, when the insulating base material in which the electric element is incorporated is deformed, a deviation may occur between the electric element and the conductive composition. Since the conductive composition is a via-hole conductor having a dense structure obtained by metallizing a conductive paste, it is relatively hard and hardly deformed. Therefore, the conductive composition may be separated from the electric element. That is, there is a possibility that the electrical connection between the conductor pattern and the electric element is broken.
　そこで、回路基板１０では、接続端子１８と電子部品２０とを金属粒子の集合体からなる接続導体３０により接続している。金属粒子の集合体からなる接続導体３０は、外力により比較的に容易に変形又は崩れることができる。したがって、積層体１２が変形させられることによって接続端子１８と電子部品２０の接続端子２４とがずれたとしても、接続導体３０は、変形することによって、接続端子１８と接続端子２４との接続状態を維持することができる。その結果、回路基板１０は、以下に説明するように、接続端子１８と電子部品２０との間において断線が発生することを抑制できる。また、従来の回路基板では電子部品の接続端子１８を構成する金属の種類によっては接続導体３０が脆くなったり、十分な電気的な接続が得られなくなってしまうことがある。本発明の回路基板１０では電子部品の接続端子１８を構成する金属の種類に依存しないで接続端子１８と接続端子２４との接続状態を維持することができる。 Therefore, in the circuit board 10, the connection terminal 18 and the electronic component 20 are connected by a connection conductor 30 made of an aggregate of metal particles. The connection conductor 30 made of an aggregate of metal particles can be deformed or broken relatively easily by an external force. Therefore, even if the connection terminal 18 and the connection terminal 24 of the electronic component 20 are displaced due to the deformation of the multilayer body 12, the connection conductor 30 is deformed so that the connection state between the connection terminal 18 and the connection terminal 24 is changed. Can be maintained. As a result, the circuit board 10 can suppress the occurrence of disconnection between the connection terminal 18 and the electronic component 20 as described below. Further, in the conventional circuit board, the connection conductor 30 may become brittle or a sufficient electrical connection may not be obtained depending on the type of metal constituting the connection terminal 18 of the electronic component. In the circuit board 10 of the present invention, the connection state between the connection terminal 18 and the connection terminal 24 can be maintained without depending on the type of metal constituting the connection terminal 18 of the electronic component.
　なお、接続導体３０は、フレキシブルシート１４により周囲を固められ、その形状が保持されている。よって、接続導体３０の金属粒子は、外力によって崩れたとしても、離れ離れになることはない。すなわち、接続導体３０の金属粒子は、積層体１２が変形させられたとしても、集合体の形態ひいては金属粒子同士の接触による導電性を維持することができる。 In addition, the periphery of the connection conductor 30 is solidified by the flexible sheet 14, and the shape is maintained. Therefore, even if the metal particles of the connection conductor 30 are broken by an external force, they are not separated from each other. That is, even if the laminated body 12 is deformed, the metal particles of the connection conductor 30 can maintain conductivity due to the form of the aggregate and the contact between the metal particles.
　また、接続導体３０の金属粒子は、０．５μｍ以上３０μｍ以下の平均粒径（Ｄ５０）を有している。金属粒子の平均粒径（Ｄ５０）を０．５μｍ以上とすることにより、加熱時に金属粒子が溶融して、接続導体３０が変形できない程度に金属化することを防止できる。また、金属粒子の平均粒径（Ｄ５０）を３０μｍ以下とすることにより、金属粒子の径が大きすぎて金属粒子間で接触不良が発生して、接続導体３０内において断線が発生することを防止できる。なお金属粒子の形状は球状であることに限定されない。フレーク状であってもよい。 Further, the metal particles of the connecting conductor 30 have an average particle diameter (D50) of 0.5 μm or more and 30 μm or less. By setting the average particle diameter (D50) of the metal particles to 0.5 μm or more, it is possible to prevent the metal particles from being melted during heating and being metalized to the extent that the connection conductor 30 cannot be deformed. In addition, by setting the average particle diameter (D50) of the metal particles to 30 μm or less, it is possible to prevent the metal particles from being too large and causing poor contact between the metal particles, and disconnection in the connection conductor 30. it can. The shape of the metal particles is not limited to being spherical. Flakes may be used.
　また、接続端子２４がＡｕにより作製され、接続導体３０の金属粒子がＡｇ又はＣｕを主成分とする単体金属又は合金により作製されている。この場合には、金属粒子の材料の方が、接続端子２４の材料よりも固くなる。その結果、フレキシブルシート１４の圧着時に、金属粒子が接続端子２４に減り込むようになる。その結果、接続導体３０と接続端子２４とがより確実に接続されるようになる。 Further, the connection terminal 24 is made of Au, and the metal particles of the connection conductor 30 are made of a single metal or alloy mainly composed of Ag or Cu. In this case, the material of the metal particles is harder than the material of the connection terminals 24. As a result, the metal particles are reduced to the connection terminals 24 when the flexible sheet 14 is crimped. As a result, the connection conductor 30 and the connection terminal 24 are more reliably connected.
　また、空洞Ｂが電子部品２０よりも僅かに大きく形成されることにより、積層・圧着時に電子部品２０がフレキシブルシート１４により押さえつけられて接続端子１８からずれてしまうことが防止される。 Further, since the cavity B is formed slightly larger than the electronic component 20, the electronic component 20 is prevented from being displaced from the connection terminal 18 by being pressed by the flexible sheet 14 during lamination / crimping.
（変形例）
　以下に、変形例に係る回路基板について図面を参照しながら説明する。図５は、変形例に係る回路基板１０の拡大図である。図５は、図１（ｂ）の拡大図に相当するものである。 (Modification)
Hereinafter, a circuit board according to a modification will be described with reference to the drawings. FIG. 5 is an enlarged view of the circuit board 10 according to the modification. FIG. 5 corresponds to the enlarged view of FIG.
　変形例に係る回路基板１０では、接続導体３０は、図５に示すように、接続端子１８のｚ軸方向の正方向側の主面のみならず側面も覆うように設けられている。これにより、接続端子１８と接続導体３０との接触面積が大きくなるので、接続端子１８と接続導体３０とをより確実に電気的に接続させることができる。また、変形例に係る回路基板１０の製造時には、接続導体１８全体を覆い隠すように導電性ペースト１３０が塗布されるようになる。その結果、接続導体１８は、空気にさらされることがなくなり、酸化されにくくなる。 In the circuit board 10 according to the modified example, the connection conductor 30 is provided so as to cover not only the main surface on the positive direction side in the z-axis direction but also the side surface of the connection terminal 18, as shown in FIG. Thereby, since the contact area of the connection terminal 18 and the connection conductor 30 becomes large, the connection terminal 18 and the connection conductor 30 can be electrically connected more reliably. Further, when the circuit board 10 according to the modification is manufactured, the conductive paste 130 is applied so as to cover the entire connection conductor 18. As a result, the connection conductor 18 is not exposed to air and is not easily oxidized.
　なお、回路基板１０では、電子部品２０を収容するための空洞Ｂを形成するために、フレキシブルシート１４の一部が打ち抜かれて空白領域Ｂ１，Ｂ２が形成されていた。しかしながら、電子部品２０のｚ軸方向の厚みが２０μｍ～１００μｍ程度であるときには、フレキシブルシート１４は、その可撓性により電子部品２０による段差を吸収することができる場合がある。よって、この場合には、フレキシブルシート１４に空白領域Ｂ１，Ｂ２を形成する必要がない。また、フレキシブルシート１４ｃ，１４ｄに空白領域Ｂ１，Ｂ２を設けることなく、フレキシブルシート１４ｃ，１４ｄの軟化・流動を利用して、電子部品２０に内蔵してもよい。 In the circuit board 10, in order to form the cavity B for accommodating the electronic component 20, a part of the flexible sheet 14 is punched to form the blank areas B1 and B2. However, when the thickness of the electronic component 20 in the z-axis direction is about 20 μm to 100 μm, the flexible sheet 14 may be able to absorb a step due to the electronic component 20 due to its flexibility. Therefore, in this case, it is not necessary to form the blank areas B1 and B2 in the flexible sheet 14. Further, the flexible sheets 14c and 14d may be embedded in the electronic component 20 by utilizing the softening and flow of the flexible sheets 14c and 14d without providing the blank areas B1 and B2.
　なお、フレキシブルシート１４の加熱時にバインダ樹脂は消失すると説明した。この消失とは、焼失のみならず分解によって消滅することも含む。すなわち、バインダ樹脂は、フレキシブルシート１４の加熱によって焼失又は分解される材料により構成されている。また、バインダ樹脂は、全てが完全に焼失することが望ましいが、金属粒子の動きを妨げない程度に残存していてもよい。 It has been described that the binder resin disappears when the flexible sheet 14 is heated. This disappearance includes not only burning but also disappearing by decomposition. That is, the binder resin is made of a material that is burned down or decomposed by heating the flexible sheet 14. Further, it is desirable that all the binder resin is completely burned out, but it may remain to the extent that the movement of the metal particles is not hindered.
　以上のように、本発明は、回路基板及びその製造方法に有用であり、特に、電子部品を内蔵している積層体であって、可撓性材料からなる絶縁体層が積層されてなる積層体を備えた回路基板において、電子部品と該電子部品が電気的に接続されている端子電極との間において断線が発生することを抑制できる点において優れている。 As described above, the present invention is useful for a circuit board and a method for manufacturing the circuit board, and in particular, a laminated body in which an electronic component is built, and a laminated body in which an insulating layer made of a flexible material is laminated. The circuit board provided with the body is excellent in that it is possible to suppress the occurrence of disconnection between the electronic component and the terminal electrode to which the electronic component is electrically connected.
　ｂ１～ｂ５　ビアホール導体
　１０　回路基板
　１２　積層体
　１４ａ～１４ｇ　フレキシブルシート
　１６ｂ～１６ｇ　導体層
　１８，２４　接続端子
　２０　電子部品
　２２　基板
　３０　接続導体 b1 to b5 Via hole conductor 10 Circuit board 12 Laminated body 14a to 14g Flexible sheet 16b to 16g Conductor layer 18, 24 Connection terminal 20 Electronic component 22 Substrate 30 Connection conductor

Claims (6)

  1. 　可撓性材料からなる複数の絶縁体層が積層されて構成されている積層体と、
    　前記積層体に設けられている接続端子と、
    　前記積層体に内蔵されている電子部品と、
    　前記電子部品と前記接続端子とを電気的に接続する接続導体であって、金属粒子の集合体からなる接続導体と、
    　を備えていること、
    　を特徴とする回路基板。     A laminate in which a plurality of insulator layers made of a flexible material are laminated;
    A connection terminal provided in the laminate,
    An electronic component built in the laminate;
    A connection conductor for electrically connecting the electronic component and the connection terminal, the connection conductor comprising an aggregate of metal particles,
    Having
    A circuit board characterized by.
  2. 　前記接続導体は、前記絶縁体層により周囲を固められていること、
    　を特徴とする請求項１に記載の回路基板。     The connection conductor has its periphery solidified by the insulator layer;
    The circuit board according to claim 1.
  3. 　前記金属粒子は、銀又は銅を含有する金属からなり、かつ、０．５μｍ以上３０μｍ以下の平均粒径（Ｄ５０）を有していること、
    　を特徴とする請求項１又は請求項２のいずれかに記載の回路基板。     The metal particles are made of a metal containing silver or copper and have an average particle diameter (D50) of 0.5 μm or more and 30 μm or less,
    The circuit board according to claim 1, wherein:
  4. 　前記接続端子は、前記絶縁体層上に設けられている導体層であり、
    　前記接続導体は、前記接続端子の主面及び側面を覆っていること、
    　を特徴とする請求項１ないし請求項３のいずれかに記載の回路基板。     The connection terminal is a conductor layer provided on the insulator layer,
    The connection conductor covers a main surface and a side surface of the connection terminal;
    The circuit board according to any one of claims 1 to 3, wherein:
  5. 　請求項１ないし請求項４のいずれかに記載の回路基板の製造方法であって、
    　前記接続端子が設けられた前記絶縁体層を準備する工程と、
    　前記金属粒子からなる導電性ペーストを、前記接続端子に塗布する工程と、
    　前記接続端子に前記電子部品を実装する工程と、
    　前記複数の絶縁体層を積層して加熱及び圧着することによって、該複数の絶縁体層同士を融着させて前記積層体を得る工程と、
    　を備え、
    　前記絶縁体層の加熱を、前記金属粒子の溶融開始温度よりも低い温度で行うこと、
    　を特徴とする回路基板の製造方法。     A method for manufacturing a circuit board according to any one of claims 1 to 4,
    Preparing the insulator layer provided with the connection terminals;
    Applying a conductive paste comprising the metal particles to the connection terminals;
    Mounting the electronic component on the connection terminal;
    A step of laminating the plurality of insulator layers and heating and pressure bonding to fuse the plurality of insulator layers together to obtain the laminate;
    With
    Heating the insulator layer at a temperature lower than the melting start temperature of the metal particles;
    A method of manufacturing a circuit board characterized by the above.
  6. 　前記導電性ペーストは、前記金属粒子及びバインダからなり、
    　前記積層体を得る工程では、加熱により前記バインダが消失すること、
    　を特徴とする請求項５に記載の回路基板の製造方法。     The conductive paste is composed of the metal particles and a binder,
    In the step of obtaining the laminate, the binder disappears by heating,
    The method of manufacturing a circuit board according to claim 5.
PCT/JP2010/067026 2009-10-01 2010-09-30 Circuit substrate and process for production thereof WO2011040502A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2011534290A JP5287991B2 (en) 2009-10-01 2010-09-30 Circuit board and manufacturing method thereof

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2009229675 2009-10-01
JP2009-229675 2009-10-01

Publications (1)

Publication Number Publication Date
WO2011040502A1 true WO2011040502A1 (en) 2011-04-07

Family

ID=43826314

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2010/067026 WO2011040502A1 (en) 2009-10-01 2010-09-30 Circuit substrate and process for production thereof

Country Status (2)

Country Link
JP (1) JP5287991B2 (en)
WO (1) WO2011040502A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013119643A1 (en) 2012-02-08 2013-08-15 Crane Electronics, Inc. Multilayer electronics assembly and method for embedding electrical circuit components within a three dimensional module
JPWO2016060073A1 (en) * 2014-10-16 2017-04-27 株式会社村田製作所 Composite device
US9888568B2 (en) 2012-02-08 2018-02-06 Crane Electronics, Inc. Multilayer electronics assembly and method for embedding electrical circuit components within a three dimensional module
WO2020122180A1 (en) * 2018-12-13 2020-06-18 株式会社村田製作所 Resin multilayer substrate and electronic device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001024333A (en) * 1999-07-12 2001-01-26 Sony Chem Corp Multilayer board and module
WO2001064807A1 (en) * 2000-02-29 2001-09-07 Matsushita Electric Industrial Co., Ltd. Conductive adhesive, apparatus for mounting electronic component, and method for mounting the same
JP2004158545A (en) * 2002-11-05 2004-06-03 Denso Corp Multilayer substrate and its manufacturing method
JP2005039158A (en) * 2003-07-18 2005-02-10 Matsushita Electric Ind Co Ltd Module with built-in component and method of manufacturing the same
JP2005310873A (en) * 2004-04-19 2005-11-04 Matsushita Electric Ind Co Ltd Manufacturing method of laminated substrate, and manufacturing facility used therefor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001024333A (en) * 1999-07-12 2001-01-26 Sony Chem Corp Multilayer board and module
WO2001064807A1 (en) * 2000-02-29 2001-09-07 Matsushita Electric Industrial Co., Ltd. Conductive adhesive, apparatus for mounting electronic component, and method for mounting the same
JP2004158545A (en) * 2002-11-05 2004-06-03 Denso Corp Multilayer substrate and its manufacturing method
JP2005039158A (en) * 2003-07-18 2005-02-10 Matsushita Electric Ind Co Ltd Module with built-in component and method of manufacturing the same
JP2005310873A (en) * 2004-04-19 2005-11-04 Matsushita Electric Ind Co Ltd Manufacturing method of laminated substrate, and manufacturing facility used therefor

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013119643A1 (en) 2012-02-08 2013-08-15 Crane Electronics, Inc. Multilayer electronics assembly and method for embedding electrical circuit components within a three dimensional module
EP2813132A4 (en) * 2012-02-08 2016-01-06 Crane Electronics Multilayer electronics assembly and method for embedding electrical circuit components within a three dimensional module
US9888568B2 (en) 2012-02-08 2018-02-06 Crane Electronics, Inc. Multilayer electronics assembly and method for embedding electrical circuit components within a three dimensional module
US11172572B2 (en) 2012-02-08 2021-11-09 Crane Electronics, Inc. Multilayer electronics assembly and method for embedding electrical circuit components within a three dimensional module
JPWO2016060073A1 (en) * 2014-10-16 2017-04-27 株式会社村田製作所 Composite device
WO2020122180A1 (en) * 2018-12-13 2020-06-18 株式会社村田製作所 Resin multilayer substrate and electronic device
US11266016B2 (en) 2018-12-13 2022-03-01 Murata Manufacturing Co., Ltd. Resin multilayer substrate and electronic apparatus

Also Published As

Publication number Publication date
JP5287991B2 (en) 2013-09-11
JPWO2011040502A1 (en) 2013-02-28

Similar Documents

Publication Publication Date Title
CN1906758B (en) Composite ceramic substrate
JP4404139B2 (en) Multilayer substrate, electronic device, and method of manufacturing multilayer substrate
JP5756515B2 (en) Chip component built-in resin multilayer substrate and manufacturing method thereof
JP4337950B2 (en) Circuit board manufacturing method
JP5093353B2 (en) Manufacturing method of component built-in module and component built-in module
WO2006011320A1 (en) Composite electronic component and its manufacturing method
JP6139653B2 (en) Component built-in resin multilayer board
CN108811319A (en) Electronic unit and its manufacturing method
JP2001332866A (en) Circuit board and method of production
JP5287991B2 (en) Circuit board and manufacturing method thereof
JPWO2009037833A1 (en) Three-dimensional printed wiring board, method for manufacturing the same, and electronic component module
JP6673304B2 (en) Multilayer board
JP2004247334A (en) Laminated ceramic electronic part, its manufacturing method, and ceramic green sheet laminated structure
JP5830864B2 (en) Capacitor built-in wiring board and method for manufacturing capacitor built-in wiring board
JP2005026573A (en) Manufacturing method of module with built-in component
JP5641072B2 (en) Circuit board
JP2008108882A (en) Electronic component and its manufacturing method
JP2002198654A (en) Electric element built-in wiring board and method of manufacturing the same
JP2007049099A (en) Ceramic electronic component and its manufacturing method
JP6323622B2 (en) Component mounting board
WO2013129154A1 (en) Manufacturing method of component-internal substrate
JP2008166456A (en) Wiring board and its manufacturing method
JP5585035B2 (en) Circuit board manufacturing method
US8304895B2 (en) Semiconductor package and method of fabricating the same
JP5078451B2 (en) Electronic component built-in module

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10820617

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2011534290

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10820617

Country of ref document: EP

Kind code of ref document: A1