WO2020250427A1 - Circuit board and mounting method - Google Patents

Circuit board and mounting method Download PDF

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Publication number
WO2020250427A1
WO2020250427A1 PCT/JP2019/023686 JP2019023686W WO2020250427A1 WO 2020250427 A1 WO2020250427 A1 WO 2020250427A1 JP 2019023686 W JP2019023686 W JP 2019023686W WO 2020250427 A1 WO2020250427 A1 WO 2020250427A1
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WO
WIPO (PCT)
Prior art keywords
circuit
heat
circuit board
sheet
solder
Prior art date
Application number
PCT/JP2019/023686
Other languages
French (fr)
Japanese (ja)
Inventor
杉山　和弘
佐藤　彰
光樹 福田
Original Assignee
株式会社ワンダーフューチャーコーポレーション
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 株式会社ワンダーフューチャーコーポレーション filed Critical 株式会社ワンダーフューチャーコーポレーション
Priority to CN201980097508.9A priority Critical patent/CN113994771A/en
Priority to PCT/JP2019/023686 priority patent/WO2020250427A1/en
Priority to KR1020217036078A priority patent/KR20210151872A/en
Priority to JP2020526340A priority patent/JP6738057B1/en
Priority to TW109119860A priority patent/TW202107645A/en
Publication of WO2020250427A1 publication Critical patent/WO2020250427A1/en

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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
    • H05K1/00—Printed circuits
    • H05K1/18—Printed circuits structurally associated with non-printed electric components
    • H05K1/181—Printed circuits structurally associated with non-printed electric components associated with surface mounted components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K1/00—Soldering, e.g. brazing, or unsoldering
    • B23K1/002—Soldering by means of induction heating
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/33—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being semiconductor devices, e.g. diodes
    • 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
    • H05K1/11—Printed elements for providing electric connections to or between printed circuits
    • H05K1/111—Pads for surface mounting, e.g. lay-out
    • 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
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • 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
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H05K3/3494—Heating methods for reflowing of solder
    • 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
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10007—Types of components
    • H05K2201/10106—Light emitting diode [LED]
    • 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
    • H05K2203/10—Using electric, magnetic and electromagnetic fields; Using laser light
    • H05K2203/101—Using electrical induction, e.g. for heating during soldering

Definitions

  • the present invention relates to a sheet-shaped circuit board and a method of mounting on the circuit board.
  • solder joining is performed by arranging the solder between the objects to be joined and then heating and melting the solder.
  • a reflow furnace heating furnace
  • a non-heat resistant resin such as polyester or polyethylene may be used instead of the conventional polyimide resin.
  • Soldering with a reflow furnace may cause thermal deformation of the substrate made of non-heat resistant resin.
  • a technique using electromagnetic induction heating has been proposed as a method for mounting electronic components on a circuit board provided on a non-heat resistant sheet (for example, Patent Document 1).
  • FIG. 18 is a conceptual diagram relating to the basic principle of electromagnetic induction heating.
  • the electromagnetic induction heating device is composed of an induction coil, a power supply, and a control device.
  • induction heating When an alternating current is passed through the induction coil, magnetic field lines with varying strength are generated. When a substance that conducts electricity (specifically, it is a bonding target and is usually formed of metal) is placed near it, eddy currents flow in the metal under the influence of these changing magnetic field lines. Since metals usually have electrical resistance, when an electric current flows through the metal, Joule heat is generated and the metal self-heats. This phenomenon is called induction heating.
  • the calorific value Q due to electromagnetic induction is expressed by the following formula.
  • a predetermined Joule heat can be obtained within a uniform magnetic field, so that the bonding accuracy is high. Further, if it is in a uniform magnetic field, a plurality of bonds can be formed at one time.
  • the metal terminals on the circuit board side generate heat, the heat is transferred to the solder, and the solder melts.
  • solder bonding by electromagnetic induction heating can be applied to the miniaturization of electronic devices and electronic parts.
  • the area of the metal terminal that is the target of heat generation will also become smaller.
  • the metal terminal area becomes even smaller.
  • the resistance R becomes large, and a sufficient amount of heat generation cannot be secured (the denominator of the above theoretical formula becomes large).
  • the calorific value Q can be secured by increasing the applied voltage V or increasing the applied time t.
  • the inventor of the present application has tried and succeeded in mounting an electronic component having a metal terminal area of about 250 ⁇ m ⁇ 250 ⁇ m. In the future, we are also considering mounting electronic components with a metal terminal area of about 50 ⁇ m ⁇ 50 ⁇ m.
  • the present invention solves the above-mentioned problems, and an object of the present invention is to provide a solder joining technique capable of dealing with a small metal terminal area.
  • the circuit board corresponds to the non-heat-resistant sheet, the circuit provided on one side of the non-heat-resistant sheet, the circuit-side terminal provided in the circuit, and the circuit-side terminal on the other side of the non-heat-resistant sheet. It is provided with a conductive pad provided at a position to be used.
  • the indirect heating (quasi-direct heating) by the conductive pad compensates for the insufficient heat generation of the circuit terminals, and the solder melts. At that time, the thermal effect on the non-heat resistant sheet is limited.
  • a plurality of the electronic components can be arranged.
  • the present invention solder bonding is possible even when the metal terminal area is small.
  • a plurality of circuit-side terminals corresponding to one electronic component are set as one unit, and the conductive pad is provided for each one unit.
  • circuit-side terminals corresponding to one electronic component are used as one unit.
  • the electronic component Since the electronic component has a large number of terminals, the area of each terminal becomes narrow. According to the present invention, solder bonding is possible even when the metal terminal area is small.
  • the size of the circuit side terminal is preferably 1 mm ⁇ 1 mm or less.
  • the terminal size is 1 mm x 1 mm or less, problems such as insufficient heat generation are occasionally seen. According to the present invention, solder bonding is possible even when the metal terminal area is small.
  • the size of the conductive pad preferably includes the one unit.
  • the indirect heating by the conductive pad surely compensates for the insufficient heat generation of the circuit terminal, and the solder melts.
  • the conductive pad is preferably circular or polygonal. It is preferably pentagonal or more.
  • the conductive pad efficiently heats indirectly.
  • the heat effect on the sheet can be suppressed.
  • the present invention that solves the above problems is a mounting method in which electronic components are solder-bonded to the circuit board.
  • the terminals of the electronic component are opposed to the circuit side terminals via solder, and the conductive pad is heated by the electromagnetic induction heating on the other surface side of the non-heat resistant sheet to generate the non heat resistant sheet and the non heat resistant sheet.
  • the heat generated by the conductive pad is conducted to the solder through the circuit-side terminal to melt the solder.
  • the indirect heating by the conductive pad compensates for the insufficient heat generation of the circuit terminals, and the solder melts.
  • the electronic component is a full-color LED with a built-in control unit.
  • the sheet-shaped display is formed by arranging the LEDs.
  • the area of each terminal becomes narrow because a large number of electronic components are arranged in a predetermined area and the LED has a large number of terminals. According to the present invention, solder bonding is possible even when the metal terminal area is small.
  • an electronic component having a narrow metal terminal area can be mounted on a sheet-shaped circuit board.
  • LED mounting structure according to this embodiment (cross-sectional view) Circuit board main part (plan view) according to this embodiment The entire circuit board according to this embodiment (plan view) Application example of this embodiment Application example of this embodiment
  • Electromagnetic induction heating (conventional example) Explanation of Principle of the Present Invention (Uneven Softening) (Cross-sectional View) Explanation of Principle of the Present Invention (Uneven Softening) (Plan View) Description of Principle of the Present Invention (Temperature Profile) Description of Principle of the Present Invention (Temperature Profile) LED mounting structure according to Modification 1 (cross-sectional view) Circuit board main part (plan view) according to the first modification BGA mounting structure according to Modification 2 (cross-sectional view) Circuit board main part (plan view) according to modification 2 Outline of FPC joining according to Modification 3 (perspective view) FPC joint main part (perspective view) according to Modification 3 FPC joining main part (cross-sectional view) according to modification 3 Basic principle of electromagnetic induction
  • FIG. 1 is a schematic cross-sectional view of the LED mounting structure according to the present embodiment.
  • the LED mounting structure is formed by soldering electronic components (for example, LEDs) 20 to a circuit board 10.
  • the LED 20 is, for example, a full-color LED with a built-in control unit, and has six terminals 21. As the LED 20 becomes smaller and the number of terminals increases, the bonding area of the terminals 21 also becomes smaller.
  • the size of the LED used in this embodiment is, for example, about 2 mm ⁇ 2 mm, and the terminal size is, for example, about 500 ⁇ m ⁇ 500 ⁇ m.
  • FIG. 2 is a plan view of a main part of the circuit board 10 according to the present embodiment
  • FIG. 3 is an overall plan view of the circuit board 10 according to the present embodiment.
  • the circuit is formed by wiring on one surface of the sheet 11.
  • the sheet 11 may be a heat-resistant resin such as polyamide-imide or polyimide, but if it is a non-heat-resistant resin such as ABS resin, acrylic, polycarbo, polyester, polybutylene, or polyurethane, the effect peculiar to the present application (details will be described later) is remarkably exhibited.
  • a heat-resistant resin such as polyamide-imide or polyimide
  • non-heat-resistant resin such as ABS resin, acrylic, polycarbo, polyester, polybutylene, or polyurethane
  • Paper, cloth, or the like may be used instead of the non-heat resistant resin.
  • PET polyethylene terephthalate
  • PET has a glass transition point of about 80 ° C. and a melting point of about 260 ° C.
  • polyamide-imide has a melting point of about 300 ° C.
  • the influence of thermal deformation or the like occurs above 300 ° C., it is treated as non-heat resistant.
  • the thickness of the sheet 11 is not particularly limited, but it is preferably about 50 to 300 ⁇ m in consideration of use as a flexible substrate.
  • the circuit is composed of wiring and terminals 12.
  • the terminal 12 is located at the end of the wiring and is arranged so as to correspond to the terminal 21 on the electronic component side. In the illustrated example, six circuit-side terminals 12 are arranged.
  • the wiring and the terminal 12 are made of a conductive material. Generally, it is a metallic material containing gold, silver, copper, aluminum, nickel, chromium and the like.
  • the wiring and the terminal 12 are formed by a general conventional method (printing, etching, metal deposition, plating, silver salt, etc.).
  • a conductive polymer, conductive carbon, or the like may be used. Further, since the wiring is sufficiently thin compared to the size of the terminal 12 and does not contribute to electromagnetic induction heating, the description thereof will be omitted below as appropriate.
  • the size of the terminal 12 is not particularly limited, but if the area is about 1 mm ⁇ 1 mm or less, defects are scattered in the conventional method, so it is preferable that the area is about 1 mm ⁇ 1 mm or less. In the examples of FIGS. 2 and 3, the size of the terminal 12 is about 400 ⁇ m ⁇ 600 ⁇ m in area.
  • the circuit side terminal 12 and the electronic component side terminal 21 are joined via solder 30. As a result, the LED 20 is mounted on the circuit board 10.
  • This embodiment has a conductive pad 40 as a characteristic configuration.
  • the conductive pad 40 is provided on the other surface side of the sheet 11 at a position corresponding to the circuit side terminal 12.
  • the sheet 11 is translucent, and when viewed from the circuit side terminal 12, the conductive pad 40 can be visually recognized through the sheet 11.
  • the six electronic component side terminals 21 are set as one unit, and the six circuit side terminals 12 corresponding to the electronic component side terminals 21 are set as one unit.
  • the conductive pad 40 corresponds to one unit (six circuit-side terminals 12).
  • the conductive pad 40 has a size that includes one unit (six circuit-side terminals 12).
  • the conductive pad 40 has a circular shape. It may be changed to a circle and made into a polygon. In the examples of FIGS. 2 and 3, the size of the conductive pad 40 is about 3 mm in diameter. However, if it is too large, the sheet 11 may be damaged.
  • the conductive pad 40 is made of a metal-based material containing gold, silver, copper, aluminum, nickel, chromium, and the like. Further, the conductive pad 40 is formed by the same method as the wiring and the circuit side terminal 12.
  • the joining method between the circuit side terminal 12 and the electronic component side terminal 21 is not limited, but solder joining is particularly preferable.
  • the solder joining method is not limited, but the electromagnetic induction heating method is particularly preferable.
  • solder bonding by electromagnetic induction heating will be described.
  • the electromagnetic induction heating device consists of an induction coil lead wire, a power supply, and a control unit (see FIG. 18).
  • the solder 30 is installed on the circuit side terminal 12, and the electronic component side terminals 21 are arranged at opposite positions via the solder 30.
  • the electromagnetic induction heating device is arranged on the conductive pad 40 side (opposite side to the electronic component mounting) and is operated. If the electronic component is not affected, an electromagnetic induction heating device may be arranged on the electronic component mounting side.
  • the area of the terminal 12 is small, and a sufficient amount of heat generation cannot be secured.
  • the conductive pad 40 has a sufficient area as compared with the terminal 12, and generates heat reliably.
  • Part of the heat generated by the conductive pad 40 is diffused on the surface of the sheet 11, but most of the heat is conducted from the sheet 11 to the circuit side terminal 12 and further to the solder 30.
  • the type of solder 30 is not limited, and general solder can be used.
  • high-temperature solder for example, SnAgCu-based solder, melting point of about 220 ° C.
  • low-temperature solder for example, SnBi solder, melting point of about 140 ° C.
  • high temperature solder since the thermal deformation of the sheet 11 can be suppressed within a range not affected (details will be described later), high temperature solder can be positively used.
  • a plurality of units are arranged vertically and horizontally on the circuit board 10 in FIG.
  • a full-color LED 20 with a built-in control unit is mounted corresponding to each unit. If a uniform magnetic field can be formed within a certain range, a plurality of solder joints can be formed at one time.
  • a sheet-like display can be formed by arranging a plurality of full-color LEDs 20 with built-in control units on the circuit board 10.
  • FIG. 4 is an image diagram of a sheet-shaped display. Since the sheet 11 is flexible, the display can also be flexibly deformed.
  • the full-color LED with built-in control unit has three RGB elements and a control unit in one electronic component.
  • the control unit selectively emits RGB based on a command signal from the outside.
  • Multiple LEDs function as color displays by controlling the signals transmitted to the full-color LEDs built into each control unit by the external main control unit. For example, it functions as a display by arranging 640 ⁇ 480 LEDs. It does not have to be a single sheet, and for example, a sheet in which 64 ⁇ 48 LEDs are arranged may be arranged in 10 ⁇ 10 sheets.
  • FIG. 5 is an image diagram showing an application example of a sheet-shaped display. Since the sheet-shaped display has flexibility, it can be wrapped around a pillar in an underground mall or the like, and functions as a digital signage.
  • the sheet-shaped display has light transmission, for example, when it is attached to a show window in a downtown area, the effect of stimulating purchase desire can be enhanced.
  • the LED when the LED is not lit, the products in the store can be visually recognized in the same way as a general show window. If you want to appeal the product to passers-by, or if you do not want to show the situation inside the store to passers-by, turn on the LED.
  • the LED has sufficient brightness and functions as a sheet-like display even during the day.
  • FIG. 6 is a simple explanatory view according to the conventional method. The conventional method will be briefly described, and the background from the conventional method to the present invention will be described.
  • the conductive pad 40 is unnecessary. Further, the size of the circuit side terminal 12 and the electronic component side terminal 21 is sufficiently wider than the area of about 1 mm ⁇ 1 mm. Further, the number of terminals of the electronic component side terminal 21 is often two, that is, the anode and the cathode. A sufficient area is secured in this respect as well.
  • the circuit side terminal 12 surely generates heat. Most of the heat generated at the circuit side terminal 12 is conducted to the solder 30, and the solder 30 melts.
  • the present invention is characterized in that the heat generated by the conductive pad 40 is indirectly used to compensate for the insufficient heat generation amount.
  • the amount of heat generated by the circuit side terminal 12 is insufficient for solder melting, a certain amount of heat is generated. Therefore, the amount of heat indirectly supplied from the conductive pad 40 may be sufficient to make up for the shortage for solder melting. Also in this respect, the absolute amount of heat supplied to the sheet 11 may be small.
  • the sheet 11 does not undergo thermal deformation.
  • FIG. 7 is a conceptual diagram of the heat path in the sheet 11. Since FIG. 7 corresponds to FIG. 1, reference numerals are omitted. Assuming that the conductive pad 40 generates heat uniformly, it is uniformly conducted to the sheet 11 on the lower surface side shown in the sheet. On the other hand, on the upper surface side shown in the sheet, the terminal 12 having a high thermal conductivity and the air having a low thermal conductivity are mixed. The heat is conducted by selecting the terminal 12 having a high thermal conductivity. That is, unevenness occurs in the heat conduction in the sheet 11.
  • FIG. 8 is a plan view showing heat conduction unevenness. Since FIG. 8 corresponds to FIG. 2, reference numerals are omitted.
  • the distance between the terminals is secured in order to prevent a short circuit.
  • the distance between the terminals is also secured in the circuit side terminal 12. In the illustrated example, even if the distance between the terminals is the narrowest, the distance corresponding to the width of the terminals 12 (at least half or more) is secured.
  • the softened area is expressed as S (soft), and the non-softened area is expressed as H (hard).
  • the softening area S is surrounded by the non-softening area H. Even if a part of the sheet softens and the molecules try to move actively, they are restrained by the surroundings. As a result, thermal deformation of the entire sheet is suppressed.
  • FIGS. 9 and 10 are temperature profiles of the conductive pad 40. In FIG. 9, information on solder melting is superimposed. In FIG. 10, information on sheet softening is superimposed. Since the objects to be compared are different, FIGS. 9 and 10 are conceptual diagrams.
  • heat above the solder melting point is supplied from the conductive pad 40 for t1 seconds (for example, about 1 to 3 seconds). Assuming that the entire amount of heat supplied Q1 is conducted to the solder 30, the solder 30 melts if the energy is equal to or greater than the energy required for melting the solder. As described in Inference 1, the amount of heat required for melting the solder is small, and the application time may be short.
  • heat that is equal to or higher than the resin glass transition point is supplied from the conductive pad 40 for t2 seconds (for example, about 4 to 10 seconds). Assuming that the entire amount of heat supplied Q2 is conducted to the sheet 11, the sheet 11 is thermally deformed if the energy is equal to or greater than the energy required for the thermal deformation of the sheet 11. However, since the application time is short, t2 is also short and the amount of heat Q2 is small. It is insufficient to thermally deform the sheet 11.
  • the mounting method of the present application has few restrictions, such as the use of a non-heat resistant material for the sheet 11 and the use of high temperature solder for the solder 30.
  • FIG. 11 is a schematic cross-sectional view of the LED mounting structure according to the modification 1.
  • FIG. 12 is a plan view of a main part of the circuit board 10 according to the first modification.
  • the conductive pad 40 is provided corresponding to one unit (six circuit-side terminals 12), but in the first modification, it corresponds to four units (six circuit-side terminals 12). A conductive pad 40 is provided. One unit corresponding to one electronic component is shown by a broken line.
  • the area of the circuit side terminal 12 As the electronic component 20 becomes smaller, the area of the circuit side terminal 12 also becomes smaller. Further, the area of the conductive pad 40 corresponding to one unit is also narrowed, and there is a possibility that a sufficient amount of heat generation cannot be secured. For example, if the size of the electronic component 20 is about 1 mm ⁇ 1 mm, the terminal size is about 250 ⁇ m ⁇ 250 ⁇ m, and the ratio example of the above embodiment is applied, the diameter of the conductive pad 40 is about 1.5 mm.
  • the conductive pad 40 corresponding to the four units is used to secure the area of the conductive pad 40 and secure the amount of heat generated. This enables reliable solder joining.
  • the size of the conductive pad 40 is assumed to be about 2.5 to 3 mm in diameter.
  • FIG. 13 is a schematic cross-sectional view of the BGA mounting structure according to the modified example 2.
  • FIG. 14 is a plan view of a main part of the circuit board 10 according to the second modification.
  • one conductive pad 40 is provided corresponding to one unit (six circuit-side terminals 12), but in the second modification, seven conductive pads 40 correspond to one unit. It is provided. One unit corresponding to one BGA is shown by a broken line.
  • the ball grit array (BGA) 20 is one of the electronic components and is a package substrate having an electrode shape in which solder balls are arranged in a grid pattern.
  • the BGA 20 has 32 terminals 21.
  • the circuit board 10 is provided with 32 terminals 12 per unit.
  • the area of the circuit side terminals 12 is further reduced.
  • one conductive pad 40 is provided corresponding to one unit, the amount of heat generated may be too large.
  • the BGA 20 size is about 5 mm ⁇ 5 mm to 10 mm ⁇ 10 mm
  • the terminal size is 500 ⁇ m ⁇ 500 ⁇ m
  • the conductive pad 40 size is about 2 mm in diameter.
  • the mounting method of the present application can be applied to mounting a chip size package (CSP).
  • CSP chip size package
  • FIG. 15 is a schematic diagram of the FPC mounting structure according to the modified example 3.
  • FIG. 16 is a perspective view of a main part of FPCs 10 and 20 according to the third modification.
  • FIG. 17 is a cross-sectional view of a main part of FPCs 10 and 20 according to the third modification.
  • the mounting of the electronic component 20 on the circuit board 10 has been described.
  • the FPC 10 is interpreted as a circuit board and the FPC 20 is interpreted as an electronic component in a broad sense, the FPCs 10 and 20 can be joined in the same manner. ..
  • FPC flexible printed circuit
  • a conductive pad 40 is provided at the back end of the FPC 10 and indirectly heated to secure the amount of heat generated. This enables reliable solder joining.
  • Modification example 4 Although it relates to solder bonding, it can be applied to other than solder bonding.
  • the mounting method of the present application can be applied to thermosetting adhesive curing.
  • thermosetting adhesive is applied to the metal part to perform electromagnetic induction heating. Heats the conductive pad 40 and reacts the thermosetting adhesive.
  • Circuit board 11 Sheet 12 Circuit side terminal 20 Electronic component 21 Electronic component side terminal 30 Solder 40 Conductive pad

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Electric Connection Of Electric Components To Printed Circuits (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

Provided is soldering technology with which it is possible to mount an electronic component having a small metal terminal area to a sheet-shaped circuit board.　An electronic component mounting structure is formed by soldering an electronic component (e.g., an LED) 20 to a circuit board 10. The circuit board 10 is provided with: a non-heat-resistant sheet 11; a circuit provided on one side of the non-heat-resistant sheet 11; a circuit-side terminal 12 provided to the circuit; and an electroconductive pad 40 provided at a position, corresponding to the circuit-side terminal 12, on the other side of the non-heat-resistant sheet 11. The circuit-side terminal 12 generates heat by electromagnetic induction heating. The heat generated by the electroconductive pad 40 is transmitted through the non-heat-resistant sheet 11 and the circuit-side terminal 12. A shortage in the amount of heat generated by the circuit-side terminal 12 is compensated through indirect heating by the electroconductive pad 40, whereby heat generation solder 30 is caused to melt.

Description

回路基板及び実装方法Circuit board and mounting method
　本発明はシート状の回路基板および当該回路基板への実装方法に関する。 The present invention relates to a sheet-shaped circuit board and a method of mounting on the circuit board.
　電子機器において、半導体等電子部品を回路基板に実装する際に、はんだ接合される。はんだ接合は、接合対象間にはんだが配置された後、はんだが加熱され溶融することによって、行われている。加熱には、一般的には、リフロー炉（加熱炉）が用いられる。 In electronic devices, when electronic components such as semiconductors are mounted on a circuit board, they are solder-bonded. Solder joining is performed by arranging the solder between the objects to be joined and then heating and melting the solder. A reflow furnace (heating furnace) is generally used for heating.
　近年、電子機器の小型、軽量化に伴い、微小な電子部品を実装する基板として、フレキシブル基板が用いられている。フレキシブル基板のコスト削減のために、従来のポリイミド樹脂に代えて、ポリエステルやポリエチレンなどの非耐熱性樹脂（低融点樹脂）が使用されることもある。 In recent years, flexible substrates have been used as substrates for mounting minute electronic components as electronic devices have become smaller and lighter. In order to reduce the cost of the flexible substrate, a non-heat resistant resin (low melting point resin) such as polyester or polyethylene may be used instead of the conventional polyimide resin.
　リフロー炉によるはんだ接合では、非耐熱性樹脂からなる基板が熱変形してしまうおそれがある。 Soldering with a reflow furnace may cause thermal deformation of the substrate made of non-heat resistant resin.
　非耐熱性シートに設けられた回路基板への電子部品実装方法として、電磁誘導加熱を用いる技術が提案されている（たとえば特許文献１）。 A technique using electromagnetic induction heating has been proposed as a method for mounting electronic components on a circuit board provided on a non-heat resistant sheet (for example, Patent Document 1).
　図１８は、電磁誘導加熱の基本原理に係る概念図である。電磁誘導加熱装置は、誘導コイルと電源と制御装置とから構成される。 FIG. 18 is a conceptual diagram relating to the basic principle of electromagnetic induction heating. The electromagnetic induction heating device is composed of an induction coil, a power supply, and a control device.
　誘導コイルに交流電流を流すと、強度の変化する磁力線が発生する。その近くに電気を通す物質（具体的には接合対象であり、通常は金属より形成される）を置くとこの変化する磁力線の影響を受けて、金属の中に渦電流が流れる。金属には通常電気抵抗があるため、金属に電流が流れると、ジュール熱が発生して、金属が自己発熱する。この現象を誘導加熱という。 When an alternating current is passed through the induction coil, magnetic field lines with varying strength are generated. When a substance that conducts electricity (specifically, it is a bonding target and is usually formed of metal) is placed near it, eddy currents flow in the metal under the influence of these changing magnetic field lines. Since metals usually have electrical resistance, when an electric current flows through the metal, Joule heat is generated and the metal self-heats. This phenomenon is called induction heating.
　電磁誘導による発熱量Ｑは次の式で表される。Ｑ＝（Ｖ２／Ｒ）×ｔ［Ｖ＝印加電圧：Ｒ＝抵抗：ｔ＝時間］ The calorific value Q due to electromagnetic induction is expressed by the following formula. Q = (V2 / R) x t [V = applied voltage: R = resistance: t = time]
　電磁誘導加熱では、金属のみ発熱するため、周辺の樹脂部分が熱損傷を受けるおそれは少ない。また、電子部品への熱影響もほぼなく、電子部品が熱損傷を受けるおそれは少ない。 In electromagnetic induction heating, only the metal generates heat, so there is little risk of thermal damage to the surrounding resin part. In addition, there is almost no thermal effect on the electronic components, and there is little risk of the electronic components being thermally damaged.
　電磁誘導加熱では、金属のみ発熱するため、少ないエネルギーでかつ短時間で接合できる。一回の接合に要する時間は数～十数秒である。 In electromagnetic induction heating, only metal generates heat, so bonding can be done with less energy and in a short time. The time required for one joining is several to ten and several seconds.
　電磁誘導加熱では、一様磁場内であれば、所定のジュール熱が得られるため、接合精度が高い。また、一様磁場内であれば、複数の接合が一度にできる。 In electromagnetic induction heating, a predetermined Joule heat can be obtained within a uniform magnetic field, so that the bonding accuracy is high. Further, if it is in a uniform magnetic field, a plurality of bonds can be formed at one time.
　電磁誘導加熱では、制御装置により電源出力量および出力時間の制御が容易である。その結果、加熱温度および加熱時間の制御も容易である。所望の温度プロファイルを設定できる。 In electromagnetic induction heating, it is easy to control the power output amount and output time by the control device. As a result, it is easy to control the heating temperature and the heating time. The desired temperature profile can be set.
　回路基板側の金属端子が発熱し、熱がはんだに伝達され、はんだが溶融する。 The metal terminals on the circuit board side generate heat, the heat is transferred to the solder, and the solder melts.
　電磁誘導加熱では、磁力を集中させるといった磁力制御も容易である（たとえば特許文献２）。これにより、接合対象近傍に接合非対象の金属が存在したとしても、接合非対象金属を加熱することなく、接合対象金属を選択的に加熱できる。 With electromagnetic induction heating, it is easy to control the magnetic force by concentrating the magnetic force (for example, Patent Document 2). As a result, even if the metal to be joined is present in the vicinity of the metal to be joined, the metal to be joined can be selectively heated without heating the metal to be joined.
　以上により、電磁誘導加熱によるはんだ接合では、電子機器や電子部品の小型化に対応できる。 From the above, solder bonding by electromagnetic induction heating can be applied to the miniaturization of electronic devices and electronic parts.
特許第6481085号公報Japanese Patent No. 6481085 特開2018-148136号公報JP-A-2018-148136
　上記の通り、電子機器や電子部品は小型化する傾向にある。そして、電磁誘導加熱によるはんだ接合は小型化傾向に対応可能である。 As mentioned above, electronic devices and electronic components tend to be smaller. Then, the solder bonding by electromagnetic induction heating can cope with the tendency of miniaturization.
　しかしながら、小型化を更に進めると、発熱対象である金属端子の面積も狭小となる。とくに、所定のエリアに多数の電子部品が配列される場合や、電子部品が多数の端子を有する場合は、金属端子面積はさらに狭小となる。その結果、抵抗Rが大きくなり、充分な発熱量を確保できなくなる（上記理論式の分母が大きくなる）。 However, if the size is further reduced, the area of the metal terminal that is the target of heat generation will also become smaller. In particular, when a large number of electronic components are arranged in a predetermined area or when the electronic components have a large number of terminals, the metal terminal area becomes even smaller. As a result, the resistance R becomes large, and a sufficient amount of heat generation cannot be secured (the denominator of the above theoretical formula becomes large).
　上記理論式に基づけば、印加電圧Vを増加させるか、印加時間ｔを増加させることにより、発熱量Qを確保できる。 Based on the above theoretical formula, the calorific value Q can be secured by increasing the applied voltage V or increasing the applied time t.
　一方で、実際に試作モデルにて検証してみると、金属端子面積が１ｍｍ×１ｍｍ程度以下になると、接合不良等の不具合が散見されるようになった。電磁誘導加熱では、印加電圧や印加時間を精度よく調整できるにもかかわらず、印加電圧や印加時間を調整しても不具合解消に限界があった。 On the other hand, when actually verifying with a prototype model, when the metal terminal area is about 1 mm x 1 mm or less, defects such as poor joining are scattered. In electromagnetic induction heating, although the applied voltage and the applied time can be adjusted accurately, there is a limit to solving the problem even if the applied voltage and the applied time are adjusted.
　なお、本願発明者は、金属端子面積２５０μｍ×２５０μｍ程度の電子部品の実装を試行し成功している。将来的には、金属端子面積５０μｍ×５０μｍ程度の電子部品の実装も視野に入れている。 The inventor of the present application has tried and succeeded in mounting an electronic component having a metal terminal area of about 250 μm × 250 μm. In the future, we are also considering mounting electronic components with a metal terminal area of about 50 μm × 50 μm.
　本発明は上記課題を解決するものであり、金属端子面積が狭小な場合でも対応可能なはんだ接合技術を提供することを目的とする。 The present invention solves the above-mentioned problems, and an object of the present invention is to provide a solder joining technique capable of dealing with a small metal terminal area.
　上記課題を解決する本発明の回路基板には、電子部品が電磁誘導加熱によりはんだ接合される。回路基板は、非耐熱性シートと、前記非耐熱性シートの一面側に設けられる回路と、前記回路に設けられる回路側端子と、前記非耐熱性シートの他面側の前記回路側端子に対応する位置に設けられる導電性パッドと、を備える。 Electronic components are solder-bonded to the circuit board of the present invention that solves the above problems by electromagnetic induction heating. The circuit board corresponds to the non-heat-resistant sheet, the circuit provided on one side of the non-heat-resistant sheet, the circuit-side terminal provided in the circuit, and the circuit-side terminal on the other side of the non-heat-resistant sheet. It is provided with a conductive pad provided at a position to be used.
　これにより、上記導電性パッドによる間接加熱（準直接加熱）が、回路端子の発熱不足を補い、はんだが溶融する。その際、非耐熱シートへの熱影響は限定的である。 As a result, the indirect heating (quasi-direct heating) by the conductive pad compensates for the insufficient heat generation of the circuit terminals, and the solder melts. At that time, the thermal effect on the non-heat resistant sheet is limited.
　上発明において好ましくは、複数の前記電子部品が配列可能である。 In the above invention, preferably, a plurality of the electronic components can be arranged.
　たとえば、シート状ディスプレイに適用できる。なお、所定エリアに、多数の電子部品が配列されることにより、各端子の面積は狭小になる。本発明によれば、金属端子面積が狭小な場合でもはんだ接合可能である。 For example, it can be applied to a sheet display. By arranging a large number of electronic components in a predetermined area, the area of each terminal becomes narrow. According to the present invention, solder bonding is possible even when the metal terminal area is small.
　上発明において好ましくは、一の電子部品に対応する複数の回路側端子を１ユニットとし、前記導電性パッドは、前記１ユニット毎に、設けられる。 In the above invention, preferably, a plurality of circuit-side terminals corresponding to one electronic component are set as one unit, and the conductive pad is provided for each one unit.
　これにより、金属端子面積が狭小な場合でもはんだ接合可能である。 As a result, solder bonding is possible even when the metal terminal area is small.
　上発明において好ましくは、一の電子部品に対応する３以上の回路側端子を１ユニットとする。 In the above invention, preferably, three or more circuit-side terminals corresponding to one electronic component are used as one unit.
　電子部品が多数の端子を有することにより、各端子の面積は狭小になる。本発明によれば、金属端子面積が狭小な場合でもはんだ接合可能である。 Since the electronic component has a large number of terminals, the area of each terminal becomes narrow. According to the present invention, solder bonding is possible even when the metal terminal area is small.
　上発明において好ましくは、前記回路側端子のサイズは、１ｍｍ×１ｍｍ以下である。 In the above invention, the size of the circuit side terminal is preferably 1 mm × 1 mm or less.
　端子サイズが１ｍｍ×１ｍｍ以下となる場合、発熱量不足等の不具合が散見される。本発明によれば、金属端子面積が狭小な場合でもはんだ接合可能である。 When the terminal size is 1 mm x 1 mm or less, problems such as insufficient heat generation are occasionally seen. According to the present invention, solder bonding is possible even when the metal terminal area is small.
　上発明において好ましくは、前記導電性パッドのサイズは、前記１ユニットを包含する。 In the above invention, the size of the conductive pad preferably includes the one unit.
　これにより、上記導電性パッドによる間接加熱が、確実に回路端子の発熱不足を補い、はんだが溶融する。 As a result, the indirect heating by the conductive pad surely compensates for the insufficient heat generation of the circuit terminal, and the solder melts.
　上発明において好ましくは、前記導電性パッドは、円形状または、多角形状である。好ましくは５角以上である。 In the above invention, the conductive pad is preferably circular or polygonal. It is preferably pentagonal or more.
　これにより、上記導電性パッドは、効率よく、間接加熱を行なう。無駄な発熱を避けるため、シートへの熱影響を抑制できる。 As a result, the conductive pad efficiently heats indirectly. In order to avoid unnecessary heat generation, the heat effect on the sheet can be suppressed.
　上記課題を解決する本発明は、上記回路基板に電子部品をはんだ接合する実装方法である。前記回路側端子に対し、はんだを介して、電子部品の端子を対向させ、前記非耐熱性シートの他面側にて前記電磁誘導加熱により前記導電性パッドを発熱させ、前記非耐熱性シートおよび前記回路側端子を介して、前記導電性パッドが発する熱をはんだに伝導させて、はんだを溶融させる。 The present invention that solves the above problems is a mounting method in which electronic components are solder-bonded to the circuit board. The terminals of the electronic component are opposed to the circuit side terminals via solder, and the conductive pad is heated by the electromagnetic induction heating on the other surface side of the non-heat resistant sheet to generate the non heat resistant sheet and the non heat resistant sheet. The heat generated by the conductive pad is conducted to the solder through the circuit-side terminal to melt the solder.
　これにより、上記導電性パッドによる間接加熱が、回路端子の発熱不足を補い、はんだが溶融する。 As a result, the indirect heating by the conductive pad compensates for the insufficient heat generation of the circuit terminals, and the solder melts.
　上記課題を解決する本発明のシート状ディスプレイにおいて、上記電子部品は制御部内臓フルカラーLEDである。シート状ディスプレイは、前記LEDが配列されることにより形成される。 In the sheet-shaped display of the present invention that solves the above problems, the electronic component is a full-color LED with a built-in control unit. The sheet-shaped display is formed by arranging the LEDs.
　シート状ディスプレイでは、所定エリアに多数の電子部品が配列されることにより、さらに、LEDが多数の端子を有することにより、各端子の面積は狭小になる。本発明によれば、金属端子面積が狭小な場合でもはんだ接合可能である。 In a sheet-shaped display, the area of each terminal becomes narrow because a large number of electronic components are arranged in a predetermined area and the LED has a large number of terminals. According to the present invention, solder bonding is possible even when the metal terminal area is small.
　本発明のはんだ接合技術によれば、狭小な金属端子面積を有する電子部品をシート状回路基板に実装できる。 According to the solder joining technique of the present invention, an electronic component having a narrow metal terminal area can be mounted on a sheet-shaped circuit board.
本実施形態に係るLED実装構造（断面図）LED mounting structure according to this embodiment (cross-sectional view) 本実施形態に係る回路基板要部（平面図）Circuit board main part (plan view) according to this embodiment 本実施形態に係る回路基板全体（平面図）The entire circuit board according to this embodiment (plan view) 本実施形態の適用例Application example of this embodiment 本実施形態の適用例Application example of this embodiment 電磁誘導加熱（従来例）Electromagnetic induction heating (conventional example) 本発明の原理説明（軟化ムラ）（断面図）Explanation of Principle of the Present Invention (Uneven Softening) (Cross-sectional View) 本発明の原理説明（軟化ムラ）（平面図）Explanation of Principle of the Present Invention (Uneven Softening) (Plan View) 本発明の原理説明（温度プロファイル）Description of Principle of the Present Invention (Temperature Profile) 本発明の原理説明（温度プロファイル）Description of Principle of the Present Invention (Temperature Profile) 変形例１に係るLED実装構造（断面図）LED mounting structure according to Modification 1 (cross-sectional view) 変形例１に係る回路基板要部（平面図）Circuit board main part (plan view) according to the first modification 変形例２に係るBGA実装構造（断面図）BGA mounting structure according to Modification 2 (cross-sectional view) 変形例２に係る回路基板要部（平面図）Circuit board main part (plan view) according to modification 2 変形例３に係るFPC接合概略（斜視図）Outline of FPC joining according to Modification 3 (perspective view) 変形例３に係るFPC接合要部（斜視図）FPC joint main part (perspective view) according to Modification 3 変形例３に係るFPC接合要部（断面図）FPC joining main part (cross-sectional view) according to modification 3 電磁誘導の基本原理Basic principle of electromagnetic induction
　＜実装構造＞
　図１は本実施形態に係るLED実装構造の概略断面図である。LED実装構造は回路基板１０に電子部品（例えばLED）２０をはんだ接合して、形成される。 <Mounting structure>
FIG. 1 is a schematic cross-sectional view of the LED mounting structure according to the present embodiment. The LED mounting structure is formed by soldering electronic components (for example, LEDs) 20 to a circuit board 10.
　LED２０は、例えば制御部内臓フルカラーLEDであり、６つの端子２１を有する。LED２０が小型化するに伴い、また端子数が多数になることにより、端子２１の接合面積も狭小化する。本実施形態で用いるLEDのサイズは例えば２ｍｍ×２ｍｍ程度であり、端子サイズは例えば５００μｍ×５００μｍ程度となる。 The LED 20 is, for example, a full-color LED with a built-in control unit, and has six terminals 21. As the LED 20 becomes smaller and the number of terminals increases, the bonding area of the terminals 21 also becomes smaller. The size of the LED used in this embodiment is, for example, about 2 mm × 2 mm, and the terminal size is, for example, about 500 μm × 500 μm.
　図２は本実施形態に係る回路基板１０の要部平面図であり、図３は本実施形態に係る回路基板１０の全体平面図である。 FIG. 2 is a plan view of a main part of the circuit board 10 according to the present embodiment, and FIG. 3 is an overall plan view of the circuit board 10 according to the present embodiment.
　回路基板１０において、回路はシート１１の一面に配線されて形成されている。シート１１は、ポリアミドイミドやポリイミドなどの耐熱性樹脂でもよいが、ABS樹脂、アクリル、ポリカーボ、ポリエステル、ポリブチレン、ポリウレタンなどの非耐熱樹脂であると、本願特有の効果（詳細後述）を顕著に発揮する。非耐熱樹脂に代えて紙や布等としてもよい。本実施形態では、一般に使用されているPET（ポリエチレンテレフタレート）を用いる。 In the circuit board 10, the circuit is formed by wiring on one surface of the sheet 11. The sheet 11 may be a heat-resistant resin such as polyamide-imide or polyimide, but if it is a non-heat-resistant resin such as ABS resin, acrylic, polycarbo, polyester, polybutylene, or polyurethane, the effect peculiar to the present application (details will be described later) is remarkably exhibited. To do. Paper, cloth, or the like may be used instead of the non-heat resistant resin. In this embodiment, PET (polyethylene terephthalate) that is generally used is used.
　なお、耐熱性樹脂および非耐熱性樹脂の厳密な定義は難しいが、PETのガラス転移点が８０℃程度、融点が２６０℃程度である一方、ポリアミドイミドの融点が３００℃程度であることから、本願では３００℃超において熱変形等の影響が発生する場合、非耐熱性と扱う。 Although it is difficult to strictly define heat-resistant resin and non-heat-resistant resin, PET has a glass transition point of about 80 ° C. and a melting point of about 260 ° C., while polyamide-imide has a melting point of about 300 ° C. In the present application, when the influence of thermal deformation or the like occurs above 300 ° C., it is treated as non-heat resistant.
　シート１１の厚さは特に限定されるものでないが、フレキシブル基板として用いることを考慮すると、５０～３００μｍ程度であることが好ましい。 The thickness of the sheet 11 is not particularly limited, but it is preferably about 50 to 300 μm in consideration of use as a flexible substrate.
　回路は配線と端子１２とから構成されている。端子１２は配線の末端にあり、電子部品側端子２１と対応するように配置されている。図示の例では、６つの回路側端子１２が配置されている。 The circuit is composed of wiring and terminals 12. The terminal 12 is located at the end of the wiring and is arranged so as to correspond to the terminal 21 on the electronic component side. In the illustrated example, six circuit-side terminals 12 are arranged.
　配線および端子１２は導電性材料により形成されている。一般的には、金、銀、銅、アルミニュウム、ニッケル、クロム等を含む金属系材料である。配線および端子１２は、一般的な従来手法（印刷、エッチング、金属蒸着、メッキ、銀塩等）によって、形成される。 The wiring and the terminal 12 are made of a conductive material. Generally, it is a metallic material containing gold, silver, copper, aluminum, nickel, chromium and the like. The wiring and the terminal 12 are formed by a general conventional method (printing, etching, metal deposition, plating, silver salt, etc.).
　なお、端子１２自身の発熱（詳細は図６等の説明にて後述）を全く期待しない場合は、導電性ポリマー、導電性カーボン等でも良い。また、端子１２のサイズに比べて配線は充分細く、電磁誘導加熱に寄与しないため、以下適宜説明を省略する。 If the terminal 12 itself is not expected to generate heat (details will be described later in FIG. 6 and the like), a conductive polymer, conductive carbon, or the like may be used. Further, since the wiring is sufficiently thin compared to the size of the terminal 12 and does not contribute to electromagnetic induction heating, the description thereof will be omitted below as appropriate.
　端子１２のサイズは特に限定されるものでないが、面積１ｍｍ×１ｍｍ程度以下になると、従来方法では不具合が散見されることから、面積１ｍｍ×１ｍｍ程度以下を本願対象とすることが好ましい。なお、図２および図３の例において、端子１２のサイズは、面積４００μｍ×６００μｍ程度である。 The size of the terminal 12 is not particularly limited, but if the area is about 1 mm × 1 mm or less, defects are scattered in the conventional method, so it is preferable that the area is about 1 mm × 1 mm or less. In the examples of FIGS. 2 and 3, the size of the terminal 12 is about 400 μm × 600 μm in area.
　回路側端子１２と電子部品側端子２１とは、はんだ３０を介して接合されている。これにより、回路基板１０にLED２０が実装される。 The circuit side terminal 12 and the electronic component side terminal 21 are joined via solder 30. As a result, the LED 20 is mounted on the circuit board 10.
　本実施形態は、特徴的な構成として、導電性パッド４０を有する。導電性パッド４０はシート１１の他面側であって、回路側端子１２に対応する位置に設けられる。なお、図２および図３において、シート１１は半透明であり、回路側端子１２側から見ると、シート１１を透過して導電性パッド４０が視認可能である。 This embodiment has a conductive pad 40 as a characteristic configuration. The conductive pad 40 is provided on the other surface side of the sheet 11 at a position corresponding to the circuit side terminal 12. In addition, in FIGS. 2 and 3, the sheet 11 is translucent, and when viewed from the circuit side terminal 12, the conductive pad 40 can be visually recognized through the sheet 11.
　本実施形態では、６つの電子部品側端子２１を１ユニットとし、電子部品側端子２１に対応する６つの回路側端子１２を１ユニットとする。導電性パッド４０は１ユニット（６つの回路側端子１２）に対応している。 In the present embodiment, the six electronic component side terminals 21 are set as one unit, and the six circuit side terminals 12 corresponding to the electronic component side terminals 21 are set as one unit. The conductive pad 40 corresponds to one unit (six circuit-side terminals 12).
　導電性パッド４０は１ユニット（６つの回路側端子１２）を包含するサイズを有する。導電性パッド４０は円形状である。円形に変えて多角形としてもよい。なお、図２および図３の例において、導電性パッド４０のサイズは、直径３ｍｍ程度である。ただし、徒に大きいと、シート１１に損傷を与えるおそれがある。 The conductive pad 40 has a size that includes one unit (six circuit-side terminals 12). The conductive pad 40 has a circular shape. It may be changed to a circle and made into a polygon. In the examples of FIGS. 2 and 3, the size of the conductive pad 40 is about 3 mm in diameter. However, if it is too large, the sheet 11 may be damaged.
　導電性パッド４０は金、銀、銅、アルミニュウム、ニッケル、クロム等を含む金属系材料により形成されている。また、導電性パッド４０は、配線や回路側端子１２と同様な手法により形成される。 The conductive pad 40 is made of a metal-based material containing gold, silver, copper, aluminum, nickel, chromium, and the like. Further, the conductive pad 40 is formed by the same method as the wiring and the circuit side terminal 12.
　＜実装方法＞
　LED２０を回路基板１０に実装する方法について説明する。回路側端子１２と電子部品側端子２１との接合方法は限定されないが、特にはんだ接合が好ましい。はんだ接合方法は限定されないが、特に電磁誘導加熱法が好ましい。以下、電磁誘導加熱よるはんだ接合について説明する。 <Implementation method>
A method of mounting the LED 20 on the circuit board 10 will be described. The joining method between the circuit side terminal 12 and the electronic component side terminal 21 is not limited, but solder joining is particularly preferable. The solder joining method is not limited, but the electromagnetic induction heating method is particularly preferable. Hereinafter, solder bonding by electromagnetic induction heating will be described.
　電磁誘導加熱装置は、誘導コイル導線と電源と制御部から構成される（図１８参照）。 The electromagnetic induction heating device consists of an induction coil lead wire, a power supply, and a control unit (see FIG. 18).
　コイル導線に交流電流を流すと、強度の変化する磁力線が発生する。その近くに電気を通す物質（本願では金属端子）を置くとこの変化する磁力線の影響を受けて、金属の中に渦電流が流れる。金属には通常電気抵抗があるため、金属に電流が流れると、ジュール熱が発生して、金属が自己発熱する。この現象を誘導加熱という。 When an alternating current is passed through the coil lead wire, magnetic field lines with varying strength are generated. When a substance that conducts electricity (metal terminal in this application) is placed near it, an eddy current flows in the metal under the influence of this changing magnetic field line. Since metals usually have electrical resistance, when an electric current flows through the metal, Joule heat is generated and the metal self-heats. This phenomenon is called induction heating.
　回路側端子１２にはんだ３０を設置し、はんだ３０を介して電子部品側端子２１を対向位置に配置する。電磁誘導加熱装置を導電性パッド４０側（電子部品実装と反対側）に配置し、作動させる。なお、電子部品に影響のない場合は、電子部品実装側に電磁誘導加熱装置を配置してもよい。 The solder 30 is installed on the circuit side terminal 12, and the electronic component side terminals 21 are arranged at opposite positions via the solder 30. The electromagnetic induction heating device is arranged on the conductive pad 40 side (opposite side to the electronic component mounting) and is operated. If the electronic component is not affected, an electromagnetic induction heating device may be arranged on the electronic component mounting side.
　本実施形態において、端子１２面積は狭小であり、充分な発熱量を確保できない。これに対し、導電性パッド４０は端子１２に比べて充分な面積を有し、確実に発熱する。 In the present embodiment, the area of the terminal 12 is small, and a sufficient amount of heat generation cannot be secured. On the other hand, the conductive pad 40 has a sufficient area as compared with the terminal 12, and generates heat reliably.
　導電性パッド４０で発生した熱は、一部はシート１１面上で拡散するが、大部分はシート１１から回路側端子１２に伝導され、さらに、はんだ３０に伝導される。 Part of the heat generated by the conductive pad 40 is diffused on the surface of the sheet 11, but most of the heat is conducted from the sheet 11 to the circuit side terminal 12 and further to the solder 30.
　これにより、はんだは溶融し、回路側端子１２と電子部品側端子２１とが接合される。 As a result, the solder melts and the circuit side terminal 12 and the electronic component side terminal 21 are joined.
　はんだ３０の種類は限定されず、一般的なはんだを用いることができる。たとえば、高温はんだ（たとえば、SnAgCu系はんだ、融点２２０℃程度）から低温はんだ（たとえば、SnBiはんだ、融点１４０℃程度）まで用いることができる。本実施形態では、シート１１の熱変形を影響ない範囲で抑制できる（詳細後述）ことから、高温はんだを積極的に用いることができる。 The type of solder 30 is not limited, and general solder can be used. For example, high-temperature solder (for example, SnAgCu-based solder, melting point of about 220 ° C.) to low-temperature solder (for example, SnBi solder, melting point of about 140 ° C.) can be used. In the present embodiment, since the thermal deformation of the sheet 11 can be suppressed within a range not affected (details will be described later), high temperature solder can be positively used.
　＜製品への適用例＞
　図３における回路基板１０には、縦横に複数のユニット（６つの回路側端子１２）が配列されている。各ユニットに対応して、制御部内臓フルカラーLED２０を実装する。なお、一定の範囲において一様磁場内を形成できれば、複数のはんだ接合が一度にできる。 <Example of application to products>
A plurality of units (six circuit-side terminals 12) are arranged vertically and horizontally on the circuit board 10 in FIG. A full-color LED 20 with a built-in control unit is mounted corresponding to each unit. If a uniform magnetic field can be formed within a certain range, a plurality of solder joints can be formed at one time.
　回路基板１０に、複数の制御部内臓フルカラーLED２０が配列されることにより、シート状ディスプレイを形成できる。 A sheet-like display can be formed by arranging a plurality of full-color LEDs 20 with built-in control units on the circuit board 10.
　図４は、シート状ディスプレイのイメージ図である。シート１１は可撓性を有するため、ディスプレイも柔軟に変形可能である。 FIG. 4 is an image diagram of a sheet-shaped display. Since the sheet 11 is flexible, the display can also be flexibly deformed.
　制御部内臓フルカラーLEDは、１つの電子部品内にRGBの３つの素子と制御部を有する。制御部は、外部からの指令信号に基づいて、RGBを選択的に発光させる。 The full-color LED with built-in control unit has three RGB elements and a control unit in one electronic component. The control unit selectively emits RGB based on a command signal from the outside.
　外部のメイン制御部が各制御部内臓フルカラーLEDに送信する信号を制御することで、複数のLEDはカラーディスプレイとして機能する。たとえば、６４０×４８０個のLEDが配列されることでディスプレイとして機能する。一枚のシートである必要はなく、たとえば、６４×４８個のLEDが配列されたシートを、１０×１０枚配列してもよい。 Multiple LEDs function as color displays by controlling the signals transmitted to the full-color LEDs built into each control unit by the external main control unit. For example, it functions as a display by arranging 640 × 480 LEDs. It does not have to be a single sheet, and for example, a sheet in which 64 × 48 LEDs are arranged may be arranged in 10 × 10 sheets.
　なお、所定エリアに、多数の電子部品が配列され、さらに、電子部品が多数の端子を有することにより、各端子の面積は狭小になる。したがって、本願技術が好適である。 Note that a large number of electronic components are arranged in a predetermined area, and the electronic components have a large number of terminals, so that the area of each terminal becomes narrow. Therefore, the technique of the present application is suitable.
　図５は、シート状ディスプレイの適用例を示すイメージ図である。シート状ディスプレイは可撓性を有するため、たとえば、地下街の支柱等に巻き付けることができ、デジタルサイネージとして機能する。 FIG. 5 is an image diagram showing an application example of a sheet-shaped display. Since the sheet-shaped display has flexibility, it can be wrapped around a pillar in an underground mall or the like, and functions as a digital signage.
　シート状ディスプレイは光透過性を有するため、たとえば、繁華街のショーウインドに貼ると、購買欲惹起効果を高めることができる。たとえば、LED非発光時は、一般的なショーウインドと同様に、店内の商品を視認可能である。通行人に商品をアピールしたい場合や、店内の状況を通行人に見せたくない場合は、LEDを発光させる。LEDは充分な輝度を有し、日中でもシート状ディスプレイとして機能する。 Since the sheet-shaped display has light transmission, for example, when it is attached to a show window in a downtown area, the effect of stimulating purchase desire can be enhanced. For example, when the LED is not lit, the products in the store can be visually recognized in the same way as a general show window. If you want to appeal the product to passers-by, or if you do not want to show the situation inside the store to passers-by, turn on the LED. The LED has sufficient brightness and functions as a sheet-like display even during the day.
　＜本願発明に至る経緯＞
　図６は従来方法に係る簡単な説明図である。従来方法について簡単に説明するとともに、従来方法から本願発明に至る経緯について説明する。 <Background to the invention of the present application>
FIG. 6 is a simple explanatory view according to the conventional method. The conventional method will be briefly described, and the background from the conventional method to the present invention will be described.
　従来方法では、導電性パッド４０は不要である。また、回路側端子１２および電子部品側端子２１のサイズは、面積１ｍｍ×１ｍｍ程度より、充分広い。また、電子部品側端子２１の端子数は、陽極と陰極の２か所であることが多い。この点でも充分な面積が確保されている。 In the conventional method, the conductive pad 40 is unnecessary. Further, the size of the circuit side terminal 12 and the electronic component side terminal 21 is sufficiently wider than the area of about 1 mm × 1 mm. Further, the number of terminals of the electronic component side terminal 21 is often two, that is, the anode and the cathode. A sufficient area is secured in this respect as well.
　電磁誘導加熱装置を電子部品実装と反対側に配置し、作動させる。これにより、回路側端子１２が確実に発熱する。回路側端子１２で発生した熱の大部分ははんだ３０に伝導され、はんだ３０は溶融する。 Place the electromagnetic induction heating device on the opposite side of the electronic component mounting and operate it. As a result, the circuit side terminal 12 surely generates heat. Most of the heat generated at the circuit side terminal 12 is conducted to the solder 30, and the solder 30 melts.
　このとき、回路側端子１２で発生した熱の一部はシート１１面上で拡散するが、はんだ３０に伝導される熱量に比べて、無視できる程度である。すなわち、シート１１に対する熱の影響はほぼ無視でき、シート１１が熱変形することはない。なお、当然ながらシート１１自体は発熱しない。 At this time, a part of the heat generated at the circuit side terminal 12 diffuses on the sheet 11 surface, but it is negligible compared to the amount of heat conducted to the solder 30. That is, the influence of heat on the sheet 11 can be almost ignored, and the sheet 11 is not thermally deformed. As a matter of course, the sheet 11 itself does not generate heat.
　これに対し、端子１２のサイズが面積１ｍｍ×１ｍｍ程度以下になると、発熱量不足による不具合が散見された。本発明では、導電性パッド４０での発熱を間接的に利用し、発熱量不足を補うことを特徴とする。 On the other hand, when the size of the terminal 12 was about 1 mm × 1 mm or less in area, problems due to insufficient heat generation were found. The present invention is characterized in that the heat generated by the conductive pad 40 is indirectly used to compensate for the insufficient heat generation amount.
　しかしながら、熱伝導の際に、多くの熱量がシート１１を経由するため、シート１１に対する熱の影響を予想できない。すなわち、シート１１熱変形のおそれが最大の懸念事項であった。そこで、本願発明者は試行錯誤を繰り返し、その結果に基づき、シート１１の熱変形はほぼ発生しないことを確かめた。 However, since a large amount of heat passes through the sheet 11 during heat conduction, the effect of heat on the sheet 11 cannot be predicted. That is, the risk of thermal deformation of the sheet 11 was the greatest concern. Therefore, the inventor of the present application repeated trial and error, and based on the result, it was confirmed that the heat deformation of the sheet 11 hardly occurred.
　＜本願原理推察＞
　すなわち、導電性パッド４０で発生した熱は、効率よくはんだ３０に伝達される。シート１１の熱変形のために用いられる熱は無視できる程度である。上記試行錯誤の結果に基づいて、本願原理について推察する。 <Inference of the principle of the present application>
That is, the heat generated by the conductive pad 40 is efficiently transferred to the solder 30. The heat used for the thermal deformation of the sheet 11 is negligible. Based on the results of the above trial and error, the principle of the present application is inferred.
　（推察１）　そもそも、従来技術に比べて、端子１２、２１のサイズが小さいということは、はんだ３０の必要量も少ない。したがって、はんだ溶融に必要な熱量も少ない。熱がシート１１を経由するとしても、シート１１に供給される熱の絶対量が少ない。 (Inference 1) In the first place, the fact that the sizes of the terminals 12 and 21 are smaller than those of the conventional technology means that the amount of solder 30 required is also small. Therefore, the amount of heat required for solder melting is also small. Even if the heat passes through the sheet 11, the absolute amount of heat supplied to the sheet 11 is small.
　さらに、回路側端子１２の発熱量ははんだ溶融に対し不十分だとしても、ある程度の量は発熱する。したがって、導電性パッド４０から間接供給される熱量は、はんだ溶融に対する不足分を補う程度でよい。この点でも、シート１１に供給される熱の絶対量は少なくてよい。 Further, even if the amount of heat generated by the circuit side terminal 12 is insufficient for solder melting, a certain amount of heat is generated. Therefore, the amount of heat indirectly supplied from the conductive pad 40 may be sufficient to make up for the shortage for solder melting. Also in this respect, the absolute amount of heat supplied to the sheet 11 may be small.
　シート１１に供給される熱の絶対量が少ない結果、シート１１は熱変形しない。 As a result of the small absolute amount of heat supplied to the sheet 11, the sheet 11 does not undergo thermal deformation.
　（推察２）　熱は、熱伝導率の高い物質を選択して移動するものと思われる。とくに、数秒（具体的には高温域が１～２秒）の加熱では、熱平衡の状態にならず、熱伝導率の差異の影響が大きいものと推測される。一般に、金属の熱伝導率は樹脂の熱伝導率より高く、樹脂の熱伝導率は空気の熱伝導率より高い。 (Inference 2) It seems that heat is transferred by selecting a substance with high thermal conductivity. In particular, it is presumed that heating for several seconds (specifically, in the high temperature range of 1 to 2 seconds) does not bring about a state of thermal equilibrium, and the difference in thermal conductivity has a large effect. In general, the thermal conductivity of metal is higher than that of resin, and the thermal conductivity of resin is higher than that of air.
　図７はシート１１内の熱経路の概念図である。なお、図７は図１に対応するため、符号を省略する。導電性パッド４０が均質に発熱すると仮定し、シート図示下面側では均質にシート１１に伝導される。一方で、シート図示上面側では、熱伝導率の高い端子１２と、熱伝導率の低い空気とが混在している。熱は、熱伝導率の高い端子１２を選択して、伝導される。すなわち、シート１１内の熱伝導にはムラが発生する。 FIG. 7 is a conceptual diagram of the heat path in the sheet 11. Since FIG. 7 corresponds to FIG. 1, reference numerals are omitted. Assuming that the conductive pad 40 generates heat uniformly, it is uniformly conducted to the sheet 11 on the lower surface side shown in the sheet. On the other hand, on the upper surface side shown in the sheet, the terminal 12 having a high thermal conductivity and the air having a low thermal conductivity are mixed. The heat is conducted by selecting the terminal 12 having a high thermal conductivity. That is, unevenness occurs in the heat conduction in the sheet 11.
　図８は、熱伝導ムラを示す平面図である。なお、図８は図２に対応するため、符号を省略する。ところで、電子部品側端子２１において、短絡を防ぐため、端子間距離が確保されている。これに対応して、回路側端子１２においても、端子間距離が確保されている。図示の例において、最も狭い端子間距離であっても、端子１２幅相当（すくなくとも半分以上）の間隔が確保されている。 FIG. 8 is a plan view showing heat conduction unevenness. Since FIG. 8 corresponds to FIG. 2, reference numerals are omitted. By the way, in the electronic component side terminal 21, the distance between the terminals is secured in order to prevent a short circuit. Correspondingly, the distance between the terminals is also secured in the circuit side terminal 12. In the illustrated example, even if the distance between the terminals is the narrowest, the distance corresponding to the width of the terminals 12 (at least half or more) is secured.
　熱伝導が端子１２相当位置に集中し、仮に、当該エリアが軟化するとしても、それ以外のエリアへの熱伝導は少なく、軟化しにくい。軟化エリアをS(soft)と表現し、非軟化エリアをH(hard)と表現する。 Heat conduction is concentrated at the position corresponding to the terminal 12, and even if the area softens, the heat conduction to other areas is small and it is difficult to soften. The softened area is expressed as S (soft), and the non-softened area is expressed as H (hard).
　軟化エリアSは非軟化エリアHに囲まれている。仮に、シート一部が軟化し、分子が活発に動き出そうとしても、周囲に拘束される。これにより、シート全体としては、熱変形が抑制される。 The softening area S is surrounded by the non-softening area H. Even if a part of the sheet softens and the molecules try to move actively, they are restrained by the surroundings. As a result, thermal deformation of the entire sheet is suppressed.
　（推察３）　図９および図１０は導電性パッド４０の温度プロファイルである。図９では、はんだ溶融にかかる情報を重ねている。図１０では、シート軟化にかかる情報を重ねている。なお、比較する対象が異なるため、図９および図１０は概念図である。 (Inference 3) FIGS. 9 and 10 are temperature profiles of the conductive pad 40. In FIG. 9, information on solder melting is superimposed. In FIG. 10, information on sheet softening is superimposed. Since the objects to be compared are different, FIGS. 9 and 10 are conceptual diagrams.
　図９において、導電性パッド４０から、はんだ溶融点以上となる熱がt1秒（例えば１～３秒程度）供給される。供給熱量Q1が全てはんだ３０に伝導されると仮定し、はんだ溶融に必要なエネルギー以上であれば、はんだ３０が溶融する。推察１で述べたとおり、はんだ溶融に必要な熱量は少なく、印加時間は短くてよい。 In FIG. 9, heat above the solder melting point is supplied from the conductive pad 40 for t1 seconds (for example, about 1 to 3 seconds). Assuming that the entire amount of heat supplied Q1 is conducted to the solder 30, the solder 30 melts if the energy is equal to or greater than the energy required for melting the solder. As described in Inference 1, the amount of heat required for melting the solder is small, and the application time may be short.
　図１０において、導電性パッド４０から、樹脂ガラス転移点以上となる熱がt2秒（例えば４～１０秒程度）供給される。供給熱量Q2が全てシート１１に伝導されると仮定し、シート１１熱変形に必要なエネルギー以上であれば、シート１１は熱変形する。しかしながら、印加時間が短いため、t2も短く、熱量Q2も少ない。シート１１を熱変形させるのには不十分である。 In FIG. 10, heat that is equal to or higher than the resin glass transition point is supplied from the conductive pad 40 for t2 seconds (for example, about 4 to 10 seconds). Assuming that the entire amount of heat supplied Q2 is conducted to the sheet 11, the sheet 11 is thermally deformed if the energy is equal to or greater than the energy required for the thermal deformation of the sheet 11. However, since the application time is short, t2 is also short and the amount of heat Q2 is small. It is insufficient to thermally deform the sheet 11.
　また、はんだは非常に短時間（瞬間的に）で溶融するのに対し、樹脂はガラス転移点以上になっても、ただちに軟化し分子が活発に動き出すわけではなく、軟化開始から熱変形までにタイムラグを有する。上記温度プロファイル（ピークが鋭い）では、軟化が進み組織が流動する前に、ガラス転移点未満となっている。 In addition, while solder melts in a very short time (instantaneously), resin does not soften immediately and the molecules do not start to move actively even when it reaches the glass transition point or higher, and from the start of softening to thermal deformation. Has a time lag. In the above temperature profile (sharp peak), it is below the glass transition point before the softening progresses and the structure flows.
　上記電磁誘導加熱に係る温度プロファイルが、シート１１熱変形抑制に寄与している可能性がある。 There is a possibility that the temperature profile related to the electromagnetic induction heating contributes to the suppression of thermal deformation of the sheet 11.
　＜効果＞
　導電性パッド４０からの間接加熱（準直接加熱）により、回路側端子１２が狭小（たとえば面積１ｍｍ×１ｍｍ程度以下）であっても、確実なはんだ接合が可能である。その際に、シート１１の熱変形が懸念されたが、問題ないことを確認した。すなわち、シート１１に対する熱の影響は無視できる。 <Effect>
By indirect heating (quasi-direct heating) from the conductive pad 40, reliable solder bonding is possible even if the circuit side terminal 12 is narrow (for example, an area of about 1 mm × 1 mm or less). At that time, there was concern about thermal deformation of the sheet 11, but it was confirmed that there was no problem. That is, the effect of heat on the sheet 11 can be ignored.
　その結果、シート１１に非耐熱性材料を用いたり、はんだ３０に高温はんだを用いたりできる等、本願実装方法は制約が少ない。 As a result, the mounting method of the present application has few restrictions, such as the use of a non-heat resistant material for the sheet 11 and the use of high temperature solder for the solder 30.
　なお、電子部品に対する熱影響もほぼない等、従来技術の効果も維持される。 Note that the effects of the conventional technology are maintained, such as almost no thermal effect on electronic components.
　＜変形例＞
　　本発明は，上記実施形態に限定されるものではなく、本願発明の技術思想の範囲で種々の変形が可能である。以下、いくつかの変形例について説明する。 <Modification example>
The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical idea of the present invention. Hereinafter, some modifications will be described.
　（変形例１）　図１１は変形例１に係るLED実装構造の概略断面図である。図１２は変形例１に係る回路基板１０の要部平面図である。 (Modification example 1) FIG. 11 is a schematic cross-sectional view of the LED mounting structure according to the modification 1. FIG. 12 is a plan view of a main part of the circuit board 10 according to the first modification.
　上記実施形態では、１ユニット（６つの回路側端子１２）に対応して導電性パッド４０が設けられているが、変形例１では、４つのユニット（６つの回路側端子１２）に対応して導電性パッド４０が設けられている。１つの電子部品に対応する１ユニットを破線で示す。 In the above embodiment, the conductive pad 40 is provided corresponding to one unit (six circuit-side terminals 12), but in the first modification, it corresponds to four units (six circuit-side terminals 12). A conductive pad 40 is provided. One unit corresponding to one electronic component is shown by a broken line.
　電子部品２０がさらに小型化するに伴い、回路側端子１２の面積もさらに狭小となる。また、１ユニットに対応する導電性パッド４０の面積も狭小となり、発熱量を充分確保できないおそれがある。例えば、電子部品２０サイズを１ｍｍ×１ｍｍ程度とし、端子サイズを２５０μｍ×２５０μｍ程度とし、上記実施形態の比率例を適用すると、導電性パッド４０の直径１．５ｍｍ程度となる。 As the electronic component 20 becomes smaller, the area of the circuit side terminal 12 also becomes smaller. Further, the area of the conductive pad 40 corresponding to one unit is also narrowed, and there is a possibility that a sufficient amount of heat generation cannot be secured. For example, if the size of the electronic component 20 is about 1 mm × 1 mm, the terminal size is about 250 μm × 250 μm, and the ratio example of the above embodiment is applied, the diameter of the conductive pad 40 is about 1.5 mm.
　変形例１では、４つのユニットに対応する導電性パッド４０とすることで、導電性パッド４０の面積を確保し、発熱量を確保する。これにより、確実なはんだ接合が可能となる。図示の例では、導電性パッド４０サイズを直径２．５～３ｍｍ程度と想定する。 In the first modification, the conductive pad 40 corresponding to the four units is used to secure the area of the conductive pad 40 and secure the amount of heat generated. This enables reliable solder joining. In the illustrated example, the size of the conductive pad 40 is assumed to be about 2.5 to 3 mm in diameter.
　（変形例２）　図１３は変形例２に係るBGA実装構造の概略断面図である。図１４は変形例２に係る回路基板１０の要部平面図である。 (Modified example 2) FIG. 13 is a schematic cross-sectional view of the BGA mounting structure according to the modified example 2. FIG. 14 is a plan view of a main part of the circuit board 10 according to the second modification.
　上記実施形態では、１ユニット（６つの回路側端子１２）に対応して１つの導電性パッド４０が設けられているが、変形例２では、１ユニットに対応して７つの導電性パッド４０が設けられている。１つのBGAに対応する１ユニットを破線で示す。 In the above embodiment, one conductive pad 40 is provided corresponding to one unit (six circuit-side terminals 12), but in the second modification, seven conductive pads 40 correspond to one unit. It is provided. One unit corresponding to one BGA is shown by a broken line.
　ボールグリットアレイ（BGA）２０は、電子部品の一つであり、はんだボールを格子状に並べた電極形状をもつパッケージ基板である。図示の例では、BGA２０は３２個の端子２１をする。これに対応して、回路基板１０には１ユニットあたり３２個の端子１２が設けられている。 The ball grit array (BGA) 20 is one of the electronic components and is a package substrate having an electrode shape in which solder balls are arranged in a grid pattern. In the illustrated example, the BGA 20 has 32 terminals 21. Correspondingly, the circuit board 10 is provided with 32 terminals 12 per unit.
　BGA２０は多数の端子２１を有する結果、回路側端子１２の面積もさらに狭小となる。一方で、１ユニットに対応して１つの導電性パッド４０を設けては、発熱量が多すぎるおそれがある。 As a result of the BGA 20 having a large number of terminals 21, the area of the circuit side terminals 12 is further reduced. On the other hand, if one conductive pad 40 is provided corresponding to one unit, the amount of heat generated may be too large.
　変形例２では、１つのユニットに対応して７つの導電性パッド４０を設けることで、過剰発熱することなく、適切な発熱量を確保する。これにより、シートを損傷させることなく、確実なはんだ接合が可能となる。 In the second modification, by providing seven conductive pads 40 corresponding to one unit, an appropriate amount of heat generation is secured without excessive heat generation. As a result, reliable solder bonding is possible without damaging the sheet.
　変形例２では、例えば、BGA２０サイズを５ｍｍ×５ｍｍ～１０ｍｍ×１０ｍｍ程度とし、端子サイズを５００μｍ×５００μｍとし、導電性パッド４０サイズを直径２ｍｍ程度とする。 In the second modification, for example, the BGA 20 size is about 5 mm × 5 mm to 10 mm × 10 mm, the terminal size is 500 μm × 500 μm, and the conductive pad 40 size is about 2 mm in diameter.
　また、同様に、チップサイズパッケージ（CSP）の実装にも本願実装方法を適用できる。 Similarly, the mounting method of the present application can be applied to mounting a chip size package (CSP).
　（変形例３）　図１５は変形例３に係るFPC実装構造の概略図である。図１６は変形例３に係るFPC１０，２０の要部斜視図である。図１７は変形例３に係るFPC１０，２０の要部断面図である。 (Modified example 3) FIG. 15 is a schematic diagram of the FPC mounting structure according to the modified example 3. FIG. 16 is a perspective view of a main part of FPCs 10 and 20 according to the third modification. FIG. 17 is a cross-sectional view of a main part of FPCs 10 and 20 according to the third modification.
　上記実施形態では、電子部品２０の回路基板１０への実装について説明したが、FPC１０を回路基板と解釈し、FPC２０を広義の電子部品と解釈すれば、FPC１０，２０同士も同様に接合可能である。 In the above embodiment, the mounting of the electronic component 20 on the circuit board 10 has been described. However, if the FPC 10 is interpreted as a circuit board and the FPC 20 is interpreted as an electronic component in a broad sense, the FPCs 10 and 20 can be joined in the same manner. ..
　FPC（フレキシブルプリント回路）は電子部品に接合される。その際、多数の配線が集中するため、端子間隔は狭くなり、１つの端子の幅は狭くなる。その結果、従来技術にかかる電磁誘導加熱では、充分な発熱量を確保できないおそれがある。 FPC (flexible printed circuit) is joined to electronic components. At that time, since a large number of wires are concentrated, the terminal spacing becomes narrow and the width of one terminal becomes narrow. As a result, there is a possibility that a sufficient amount of heat generation cannot be secured by the electromagnetic induction heating according to the prior art.
　変形例３では、FPC１０裏面端部に導電性パッド４０を設け間接加熱することで、発熱量を確保する。これにより、確実なはんだ接合が可能となる。 In the third modification, a conductive pad 40 is provided at the back end of the FPC 10 and indirectly heated to secure the amount of heat generated. This enables reliable solder joining.
　（変形例４）
　はんだ接合に係るものであるが、はんだ接合以外にも適用できる。たとえば、熱硬化型接着剤硬化に、本願実装方法を適用することができる。 (Modification example 4)
Although it relates to solder bonding, it can be applied to other than solder bonding. For example, the mounting method of the present application can be applied to thermosetting adhesive curing.
　具体的には、プラスティック筐体と金属部品が一体になっている成型品に対し、裏面に導電性パッド４０を設けるとともに、金属部品に熱硬化型接着剤を塗付しておき、電磁誘導加熱により導電性パッド４０を発熱させ、熱硬化型接着剤を反応させる。 Specifically, for a molded product in which a plastic housing and a metal part are integrated, a conductive pad 40 is provided on the back surface, and a thermosetting adhesive is applied to the metal part to perform electromagnetic induction heating. Heats the conductive pad 40 and reacts the thermosetting adhesive.
　　１０　回路基板
　　１１　シート
　　１２　回路側端子
　　２０　電子部品
　　２１　電子部品側端子
　　３０　はんだ
　　４０　導電性パッド 10 Circuit board 11 Sheet 12 Circuit side terminal 20 Electronic component 21 Electronic component side terminal 30 Solder 40 Conductive pad

Claims (9)

  1. 　電子部品が電磁誘導加熱によりはんだ接合される回路基板であって、
    　非耐熱性シートと、前記非耐熱性シートの一面側に設けられる回路と、前記回路に設けられる回路側端子と、
    　前記非耐熱性シートの他面側の前記回路側端子に対応する位置に設けられる導電性パッドと、
    　を備えることを特徴とする回路基板。     A circuit board in which electronic components are solder-bonded by electromagnetic induction heating.
    A non-heat-resistant sheet, a circuit provided on one side of the non-heat-resistant sheet, and a circuit-side terminal provided in the circuit.
    A conductive pad provided at a position corresponding to the circuit side terminal on the other surface side of the non-heat resistant sheet, and
    A circuit board characterized by comprising.
  2. 　複数の前記電子部品が配列可能である
    　ことを特徴とする請求項１記載の回路基板。     The circuit board according to claim 1, wherein a plurality of the electronic components can be arranged.
  3. 　一の電子部品に対応する複数の回路側端子を１ユニットとし、
    　前記導電性パッドは、前記１ユニット毎に、設けられる
    　ことを特徴とする請求項１または２記載の回路基板。     Multiple circuit-side terminals corresponding to one electronic component are regarded as one unit.
    The circuit board according to claim 1 or 2, wherein the conductive pad is provided for each unit.
  4. 　一の電子部品に対応する３以上の回路側端子を１ユニットとする
    　ことを特徴とする請求項１～３記載の回路基板。     The circuit board according to claim 1 to 3, wherein three or more circuit-side terminals corresponding to one electronic component are one unit.
  5. 　前記回路側端子のサイズは、１ｍｍ×１ｍｍ以下である
    　ことを特徴とする請求項１～４記載の回路基板。     The circuit board according to claim 1 to 4, wherein the size of the circuit side terminal is 1 mm × 1 mm or less.
  6. 　前記導電性パッドのサイズは、前記１ユニットを包含する
    　ことを特徴とする請求項３または４記載の回路基板。     The circuit board according to claim 3 or 4, wherein the size of the conductive pad includes the one unit.
  7. 　前記導電性パッドは、円形状または、多角形状である
    　ことを特徴とする請求項１～６記載の回路基板。     The circuit board according to claim 1 to 6, wherein the conductive pad has a circular shape or a polygonal shape.
  8. 　請求項１記載の回路基板に電子部品をはんだ接合する実装方法であって、
    　前記回路側端子に対し、はんだを介して、電子部品の端子を対向させ、
    　前記非耐熱性シートの他面側にて前記電磁誘導加熱により前記導電性パッドを発熱させ、
    　前記非耐熱性シートおよび前記回路側端子を介して、前記導電性パッドが発する熱をはんだに伝導させて、はんだを溶融させる
    　ことを特徴とする実装方法。     A mounting method for soldering electronic components to the circuit board according to claim 1.
    The terminals of the electronic components are opposed to the circuit side terminals via solder.
    The conductive pad is heated by the electromagnetic induction heating on the other surface side of the non-heat resistant sheet.
    A mounting method characterized by conducting heat generated by the conductive pad to solder through the non-heat resistant sheet and the circuit side terminal to melt the solder.
  9. 　請求項２記載の電子部品は、制御部内臓フルカラーLEDであって、
    　前記LEDが配列されることにより形成される
    　ことを特徴とするシート状ディスプレイ。     The electronic component according to claim 2 is a full-color LED with a built-in control unit.
    A sheet-like display characterized in that it is formed by arranging the LEDs.
PCT/JP2019/023686 2019-06-14 2019-06-14 Circuit board and mounting method WO2020250427A1 (en)

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Citations (5)

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JP2000183513A (en) * 1998-12-16 2000-06-30 Nec Corp Device for releasing connection of circuit board with electronic component and its method
JP2009164404A (en) * 2008-01-08 2009-07-23 Fujitsu Ltd Repair method of electronic component, repair device, and wiring board unit
JP3163841U (en) * 2010-08-23 2010-11-04 黄顯榮 Modular LED display and its system
JP2013171863A (en) * 2012-02-17 2013-09-02 Panasonic Corp Electronic component mounting structure and manufacturing method of the same
JP2018148136A (en) * 2017-03-08 2018-09-20 東レエンジニアリング株式会社 Solder joint device

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JP2000183513A (en) * 1998-12-16 2000-06-30 Nec Corp Device for releasing connection of circuit board with electronic component and its method
JP2009164404A (en) * 2008-01-08 2009-07-23 Fujitsu Ltd Repair method of electronic component, repair device, and wiring board unit
JP3163841U (en) * 2010-08-23 2010-11-04 黄顯榮 Modular LED display and its system
JP2013171863A (en) * 2012-02-17 2013-09-02 Panasonic Corp Electronic component mounting structure and manufacturing method of the same
JP2018148136A (en) * 2017-03-08 2018-09-20 東レエンジニアリング株式会社 Solder joint device

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