JP2010135476A - Circuit structure body and method for manufacturing the circuit structure body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit structure body which improves the reliability for the electrical connection of an FPC, and to provide a method for manufacturing the circuit structure body. <P>SOLUTION: A circuit structure body 12 is provided with an FPC 14; a plurality of conductive paths 15 which are attached in the FPC 14; and a prepreg 16, which is laminated in the surface opposite to the surface attached in the FPC 14 among the conductive paths 15. The conductive paths 15 are formed by etching a metal plate 22, while attaching the FPC 14 or the prepreg 16 in either the front surface or the rear surface of a metal plate 22, which has the front surface and the back surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit structure and a method for manufacturing the circuit structure.

The thing of patent document 1 is known as an electrical junction box which accommodates a circuit structure in a case. In this case, an FPC (flexible printed circuit board) is accommodated in a case.
JP 2002-78151 A

  However, since the thickness of the FPC is extremely thin, there is a concern that the electrical connection reliability of the FPC may be reduced due to the FPC being bent and deformed by vibration or the like.

  The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a circuit structure and a method for manufacturing the circuit structure that improve the electrical connection reliability of the FPC.

  The present invention is a method of manufacturing a circuit structure, and includes an FPC bonding step of bonding an FPC to the surface of a metal plate material having a front surface and a back surface, and a plurality of layers disposed apart from each other by etching the metal plate material. An etching process for forming the conductive path, a prepreg lamination process for laminating a prepreg on the back surface of the conductive path, and a prepreg curing process for curing the prepreg.

  Further, the present invention is a method for manufacturing a circuit structure, wherein a first etching step of forming a bottomed groove by etching a back surface of a metal plate material having a front surface and a back surface, and a prepreg on the back surface of the metal plate material A prepreg laminating step for laminating, a prepreg curing step for curing the prepreg, a second etching step for forming a plurality of conductive paths separated from each other by etching the surface of the metal plate material, and the second etching step. A filling step of filling an insulating synthetic resin material in a gap between the formed adjacent conductive paths and an FPC bonding step of bonding FPC to the surface of the metal plate material are performed.

  In addition, the present invention is a circuit structure, and includes a FPC, a plurality of conductive paths affixed to the FPC, and a prepreg laminated on a surface of the conductive path opposite to the surface affixed to the FPC. The conductive path is formed by etching the other of the front and back surfaces of the metal plate material with FPC or prepreg attached to one of the front and back surfaces of the metal plate material having the front and back surfaces. The

  According to the present invention, a conductive path is bonded to an FPC (flexible printed circuit board), and a prepreg is laminated on the conductive path and cured. As a result, the FPC is prevented from being bent and deformed, so that the electrical connection reliability of the circuit structure using the FPC can be improved.

As embodiments of the present invention, the following embodiments are preferable.
An opening step of opening a window portion in the FPC, and a protrusion forming step of forming a protrusion having substantially the same height as the surface of the FPC on the surface of the conductive path exposed from the window portion. Execute.

  According to the above aspect, when the electronic component is mounted across the surface of the FPC and the conductive path exposed from the window, the step of providing a step corresponding to the thickness dimension of the FPC on the lead of the electronic component is performed. It becomes unnecessary. Thereby, the mounting process of an electronic component can be simplified.

  The said convex part formation process may form the said convex part by performing a plating process to the surface of the said metal plate material exposed from the said window part.

  Moreover, the said convex part formation process may form the said convex part by apply | coating an electrically conductive paste to the surface of the said metal plate material exposed from the said window part.

  Moreover, the said convex part formation process may form the said convex part by knocking out the part corresponding to the said window part among the said metal plate materials from the back surface side of the said metal plate material.

  As said metal plate material, you may use the thickness dimension of 100 micrometers or more and 640 micrometers or less.

  If the thickness dimension of the metal plate is less than 100 μm, the electric resistance of the conductive path is increased, and therefore a relatively large current cannot be passed through the conductive path. On the other hand, if the thickness dimension of the metal plate exceeds 640 μm, the work time during the etching process is prolonged, which is not preferable.

  In addition, the present invention is an electrical connection box, comprising: the circuit structure body; and a case that accommodates the circuit structure body therein, wherein the case has an opening, and the opening is formed from the opening. The prepreg of the circuit board is exposed, and the prepreg also serves as the case.

  According to the present invention, the heat generated from the circuit structure when energized is directly dissipated from the prepreg exposed from the opening of the case to the outside of the case. Thereby, the heat dissipation of an electrical junction box can be improved.

  According to the present invention, the electrical connection reliability of the FPC can be improved.

<Embodiment 1>
A first embodiment in which the present invention is applied to an electric junction box 10 mounted on a vehicle will be described with reference to FIGS. The electrical connection box 10 is disposed between a power source (not shown) and in-vehicle electrical components (not shown) such as a lamp and a horn, and performs switching of the in-vehicle electrical components. The electrical junction box 10 according to the present embodiment is configured by housing a circuit structure 12 in a case 11.

  The case 11 is made of synthetic resin and has an opening 13 that opens downward in FIG. A circuit structure 12 is accommodated in the case 11. The circuit structure 12 is laminated on the FPC 14 (flexible printed circuit board), a plurality of metal conductive paths 15 bonded to the back surface (lower surface in FIG. 1) of the FPC 14, and the back surface (lower surface in FIG. 1) of the conductive path 15. And a prepreg 16 cured after being cured. The prepreg 16 of the circuit structure 12 is exposed from the opening 13 of the case 11, and also serves as a part of the case 11.

  A substrate-side conductive path 17 is formed on the surface of the FPC 14 by a printed wiring technique. Electronic components such as a semiconductor relay 18 are mounted on the board-side conductive path 17. The first lead 19 protruding from the side surface of the semiconductor relay 18 is connected to the board-side conductive path 17 by, for example, reflow soldering. As thickness dimension of FPC14, a 0.1 mm-0.2 mm thing can be used, for example.

  The FPC 14 is provided with a window portion 20 that penetrates the FPC 14. The conductive path 15 is exposed from the window portion 20. A convex portion 21 protruding toward the FPC 14 is formed at a position corresponding to the window portion 20 in the conductive path 15. The convex portion 21 is formed at substantially the same height as the surface of the FPC 14. “Substantially the same height” includes a case in which the convex portion 21 and the surface of the FPC 14 have the same height, and the height dimensions are close enough to be recognized as substantially the same even if they are not the same height. Including the case of having In addition, it is preferable that the convex part 21 is formed in the substantially same height as the board | substrate side conductive path 17 formed in the surface of FPC14.

  Although not shown in detail, a second lead is formed on the lower surface of the semiconductor relay 18 (the lower surface in FIG. 1). The second lead is connected to the convex portion 21 exposed from the window portion 20 opened in the FPC 14 by, for example, reflow soldering. Thus, the semiconductor relay 18 is connected across the board-side conductive path 17 and the conductive path 15 of the FPC 14.

  The metal conductive path 15 is formed by etching a metal plate material 22 described later. As the metal plate material 22, it is preferable to use copper or a copper alloy. The thickness dimension of the conductive path 15 (metal plate material 22) is preferably 100 μm or more and 640 μm or less. If the thickness dimension of the metal plate material 22 is less than 100 μm, the electric resistance of the conductive path 15 becomes large, so that a relatively large current cannot flow through the conductive path 15, which is not preferable. On the other hand, when the thickness dimension of the metal plate material 22 exceeds 640 μm, the working time during the etching process is prolonged, which is not preferable. Among the plurality of conductive paths 15, the space between adjacent conductive paths 15 is filled with a prepreg 16. Any prepreg 16 can be used as necessary. The synthetic resin impregnated in the prepreg 16 preferably has a thermal conductivity of 1 W / (mK) or more and 3 W / (mK) or less. As the prepreg 16, for example, a glass fiber impregnated with an epoxy resin can be used.

  Then, an example of the manufacturing process of this embodiment is shown. In each of the following processes, a pretreatment process such as a cleaning process, which is executed in normal substrate manufacturing, may be performed. First, the board-side conductive path 17 is formed on the FPC 14 by a printed wiring technique. Next, a window portion 20 is formed at a predetermined position of the FPC 14 (see FIG. 2). In FIG. 2, the substrate-side conductive path 17 is omitted.

  As shown in FIG. 3, the FPC 14 is bonded to the surface of the metal plate member 22 (the upper surface in FIG. 3). The metal plate material 22 and the FPC 14 may be bonded by an adhesive or may be bonded by an adhesive sheet. In addition, the adhesive strength between the metal plate material 22 and the FPC 14 can be improved by performing a surface treatment such as a known blackening treatment on the surface of the metal plate material 22.

  Subsequently, the back surface of the metal plate material 22 is etched. First, when exposed from the window portion 20 of the FPC 14, a known masking process is performed on the conductive path 15. Thereafter, a masking process is performed on a position corresponding to the conductive path 15 on the back surface of the metal plate material 22. Subsequently, a known etching process is performed. As a result, a plurality of conductive paths 15 are formed as shown in FIG. Thereafter, the surface of the conductive path 15 exposed from the window portion 20 of the FPC 14 is washed, and the mask is removed.

  Subsequently, as shown in FIG. 5, the convex portion 21 is formed on the surface of the conductive path 15 exposed from the window portion 20 of the FPC 14 until the height is substantially the same as the substrate-side conductive path 17 of the FPC 14. The convex portion 21 can be formed by performing a known plating process on the conductive path 15 exposed from the window portion 20 of the FPC 14. Arbitrary metal can be used as a metal which comprises the convex part 21, and copper or a copper alloy is preferable.

  Moreover, the convex part 21 can be formed by apply | coating the electrically conductive paste containing a metal powder to the electrically conductive path 15 exposed from the window part 20 of FPC14. The conductive paste can be applied by any means, and for example, can be applied by screen printing.

  Subsequently, as shown in FIG. 6, the prepreg 16 is laminated on the back surface (the lower surface in FIG. 6) of the conductive path 15 (metal plate material 22). At this time, by stacking a plurality of prepregs 16, gaps between adjacent conductive paths 15 are filled with the prepregs 16. As a technique for laminating the prepreg 16, a known technique can be used. First, a semi-cured prepreg 16 sheet is laminated on the back surface of the conductive path 15. Next, the prepreg 16 is thermally cured by hot pressing under predetermined conditions. Note that the back surface of the conductive path 15 may be blackened.

  Further, when the thickness dimension of the conductive path 15 is 200 μm or more, there is a possibility that the gap between the adjacent conductive paths 15 cannot be sufficiently filled only with the resin of the prepreg. In this case, a gap between adjacent conductive paths 15 may be filled with an insulating synthetic resin in advance, and then the prepreg 16 may be laminated on the back surface of the conductive paths 15 and hot pressed under predetermined conditions.

  Thereafter, the semiconductor relay 18 and the like are mounted on the FPC 14 and accommodated in the case 11 to complete the electrical junction box 10.

  Then, the effect | action and effect of this embodiment are demonstrated. According to this embodiment, the conductive path 15 is bonded to the FPC 14, and the prepreg 16 is laminated on the conductive path 15 and cured. As a result, the FPC 14 is restrained from being bent and deformed, so that the electrical connection reliability of the circuit structure 12 using the FPC 14 can be improved.

  According to the present embodiment, the window portion 20 is opened in the FPC 14, and the convex portion 21 protruding to the FPC 14 side is formed in the conductive path 15 exposed from the window portion 20. Is formed at substantially the same height as the surface of the FPC 14. As a result, when an electronic component is mounted across the surface of the FPC 14 and the conductive path 15 exposed from the window portion 20, it is unnecessary to provide a step corresponding to the thickness dimension of the FPC 14 on the lead of the electronic component. Become. Thereby, the mounting process of an electronic component can be simplified.

  Further, according to the present embodiment, the metal plate material 22 having a thickness dimension of 100 μm or more and 640 μm or less is used. If the thickness dimension of the metal plate material 22 is less than 100 μm, the electric resistance of the conductive path 15 is increased, so that a relatively large current cannot be passed through the conductive path 15, which is not preferable. On the other hand, when the thickness dimension of the metal plate material 22 exceeds 640 μm, the working time during the etching process is prolonged, which is not preferable.

  Further, according to the present embodiment, the opening 11 is formed in the case 11, and the prepreg 16 of the circuit board is exposed from the opening 13, and the prepreg 16 also serves as the case 11. Thereby, the heat generated from the circuit structure 12 during energization is directly dissipated from the prepreg 16 exposed from the opening 13 of the case 11 to the outside of the case 11. Thereby, the heat dissipation of the electrical junction box 10 can be improved.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 12, in the circuit structure 12 according to the present embodiment, the convex portion 21 formed on the conductive path 15 exposed from the window portion 20 of the FPC 14 is the back surface of the conductive path 15 (the lower surface in FIG. 12). It is formed by beating from.

  Further, the gap between the adjacent conductive paths 15 is filled with the prepreg 16 and the synthetic resin material 23.

  Then, an example of the manufacturing method of this embodiment is demonstrated. First, as shown in FIG. 7, the front surface (upper surface in FIG. 7) of the metal plate material 22 is masked, and the back surface (lower surface in FIG. 7) of the metal plate material 22 is also masked at a predetermined position. Next, a bottomed groove 24 is formed on the back surface of the metal plate material 22 by performing a first etching process on the metal plate material 22.

  Next, as shown in FIG. 8, when the FPC 14 is bonded to the metal plate member 22, a punching process is performed from the back surface (surface opposite to the FPC 14) of the metal plate member 22 at a position corresponding to the window portion 20 of the FPC 14. By doing so, the convex part 21 which protrudes to the surface side of the metal plate material 22 is formed.

  Next, as shown in FIG. 9, the semi-cured prepreg 16 is laminated on the back surface (the lower surface in FIG. 9) of the metal plate material 22. At this time, a necessary number of prepregs 16 are stacked so that the inside of the bottomed groove 24 is filled with the prepreg 16. Thereafter, the prepreg 16 is cured by executing a thermosetting press under predetermined conditions.

  Thereafter, as shown in FIG. 10, a masking process is performed on a predetermined position on the surface of the metal plate material 22 (upper surface in FIG. 10), and then the second etching process is performed to remove the bottom of the bottomed groove 24. Then, a plurality of conductive paths 15 separated from each other are formed.

  Next, as shown in FIG. 11, an insulating synthetic resin material 23 is filled into the gap between the adjacent conductive paths 15 from the surface (upper surface in FIG. 11) side of the conductive path 15 (metal plate material 22). The synthetic resin material 23 can be filled by a known method, and can be filled by, for example, screen printing.

  Subsequently, the window portion 20 is formed at a predetermined position of the FPC 14. After that, as shown in FIG. 12, the FPC 14 is bonded to the surface of the conductive path 15 (upper surface in FIG. 12) while aligning the window portion 20 of the FPC 14 and the convex portion 21 of the conductive path 15 (metal plate material 22). To do.

  Since the configuration other than the above is substantially the same as that of the first embodiment, the same members are denoted by the same reference numerals, and redundant description is omitted.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIGS. First, as shown in FIG. 13, the surface of the metal plate material 22 (upper surface in FIG. 13) is masked, and the back surface of the metal plate material 22 (lower surface in FIG. 13) is also masked at a predetermined position. Next, by performing a first etching process on the metal plate material 22, a bottomed groove 24 is formed on the back surface of the metal plate material 22.

  Next, as shown in FIG. 14, the semi-cured prepreg 16 is laminated on the back surface (the lower surface in FIG. 14) of the metal plate material 22. At this time, a predetermined number of prepregs 16 are laminated so that the inside of the bottomed groove 24 is filled with the prepreg 16. Thereafter, the prepreg 16 is cured by executing a thermosetting press under predetermined conditions.

  After that, as shown in FIG. 15, the bottom of the bottomed groove 24 is removed by performing a second etching process after performing a masking process on a predetermined position on the surface of the metal plate 22 (the upper surface in FIG. 10). Then, a plurality of conductive paths 15 separated from each other are formed.

  Next, as shown in FIG. 16, an insulating synthetic resin material 23 is filled into the gap between the adjacent conductive paths 15 from the surface (upper surface in FIG. 16) side of the conductive path 15 (metal plate material 22). The synthetic resin material 23 can be filled by a known method, and can be filled by, for example, screen printing.

  Subsequently, the window portion 20 is formed at a predetermined position of the FPC 14. Thereafter, as shown in FIG. 17, the FPC 14 is bonded to the surface of the conductive path 15 (the upper surface of FIG. 17).

  Thereafter, as shown in FIG. 18, the convex portion 21 is formed at a position corresponding to the window portion 20 of the FPC 14 until the height is substantially the same as the substrate-side conductive path 17 of the FPC 14. The convex portion 21 can be formed by performing a known plating process on the conductive path 15 exposed from the window portion 20 of the FPC 14. Arbitrary metal can be used as a metal which comprises the convex part 21, and copper or a copper alloy is preferable. Moreover, the convex part 21 can be formed by apply | coating the electrically conductive paste containing a metal powder to the electrically conductive path 15 exposed from the window part 20 of FPC14. The conductive paste can be applied by any means, and for example, can be applied by screen printing.

  Since the configuration other than the above is substantially the same as that of the second embodiment, the same members are denoted by the same reference numerals, and redundant description is omitted.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) Although the window portion 20 is formed in the FPC 14 in this embodiment, the window portion 20 can be omitted.
(2) In the present embodiment, the prepreg 16 of the circuit structure 12 is exposed from the opening 13 of the case 11. However, the present invention is not limited to this, and the circuit 11 is not provided with the opening 13. It is good also as a structure which 12 is not exposed outside.
(3) Although the semiconductor relay 18 is shown as the electronic component mounted on the FPC 14, it is not limited thereto, and any electronic component such as a mechanical relay, resistor, microcomputer, etc. can be mounted as necessary.

Sectional drawing which shows the electrical-connection box using the circuit structure based on Embodiment 1 of this invention Sectional drawing which shows the process of forming a window part in FPC Sectional drawing which shows the process of adhere | attaching a metal plate material on FPC Sectional drawing which shows the state which performed the etching process to the metal plate material Sectional drawing which shows the state which formed the convex part Sectional drawing which shows the state which laminated | stacked the prepreg Sectional drawing which shows the state which performed the 1st etching process to the metal plate material among the manufacturing processes of the circuit structure which concerns on Embodiment 2. FIG. Sectional drawing which shows the state which formed the convex part Sectional drawing which shows the state which laminated | stacked the prepreg Sectional drawing which shows the state which performed the 2nd etching process Sectional drawing which shows the state which filled the gap between adjacent conductive paths with the synthetic resin material Sectional drawing which shows the state which adhered FPC to the conductive path Sectional drawing which shows the state which performed the 1st etching process to the metal plate material among the manufacturing processes of the circuit structure which concerns on Embodiment 3. FIG. Sectional drawing which shows the state which laminated | stacked the prepreg Sectional drawing which shows the state which performed the 2nd etching process Sectional drawing which shows the state which filled the gap between adjacent conductive paths with the synthetic resin material Sectional drawing which shows the state which adhered FPC to the conductive path Sectional drawing which shows the state which formed the convex part

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electric junction box 11 ... Case 12 ... Circuit structure 13 ... Opening part 14 ... FPC (flexible printed circuit board)
DESCRIPTION OF SYMBOLS 15 ... Conductive path 16 ... Prepreg 20 ... Window part 21 ... Convex part 22 ... Metal plate material 23 ... Synthetic resin material

Claims (11)

An FPC bonding process for bonding an FPC to the surface of a metal plate having a front surface and a back surface; an etching process for forming a plurality of conductive paths spaced apart from each other by etching the metal plate; and A method for manufacturing a circuit structure, comprising: a prepreg laminating step for laminating a prepreg on a back surface; and a prepreg curing step for curing the prepreg. A first etching step of forming a bottomed groove by etching a back surface of a metal plate material having a front surface and a back surface; a prepreg lamination step of laminating a prepreg on the back surface of the metal plate material; and a prepreg curing step of curing the prepreg. Etching the surface of the metal plate material to form a plurality of conductive paths that are separated from each other, and a gap between adjacent conductive paths formed by the second etching process is an insulating compound. A method for manufacturing a circuit structure, comprising: a filling step of filling a resin material; and an FPC bonding step of bonding an FPC to the surface of the metal plate material. An opening step of opening a window portion in the FPC, and a protrusion forming step of forming a protrusion having substantially the same height as the surface of the FPC on the surface of the conductive path exposed from the window portion. The manufacturing method of the circuit structure according to claim 1 or claim 2 to be executed. The said convex part formation process is a manufacturing method of the circuit structure of Claim 3 which forms the said convex part by performing a plating process on the surface of the said metal plate material exposed from the said window part. The said convex part formation process is a manufacturing method of the circuit structure of Claim 3 which forms the said convex part by apply | coating an electrically conductive paste to the surface of the said metal plate material exposed from the said window part. The said convex part formation process manufactures the circuit structure body of Claim 3 which forms the said convex part by knocking out the part corresponding to the said window part among the said metal plate materials from the back surface side of the said metal plate material. Method. The method for manufacturing a circuit structure according to any one of claims 1 to 6, wherein a thickness of the metal plate is 100 µm or more and 640 µm or less. An FPC, a plurality of conductive paths affixed to the FPC, and a prepreg laminated on a surface of the conductive path opposite to the surface affixed to the FPC,
The conductive path is a circuit structure formed by etching the other of the front and back surfaces of the metal plate material in a state where FPC or prepreg is pasted on one of the front and back surfaces of the metal plate material having a front surface and a back surface. The circuit structure according to claim 8, wherein a thickness dimension of the conductive path is 100 μm or more and 640 μm or less. The FPC has a window portion, and the conductive path exposed from the window portion is formed with a convex portion protruding toward the FPC side, and the convex portion is connected to the conductive path of the FPC. The circuit structure according to claim 8 or 9, wherein the circuit structure is formed at substantially the same height as the surface on the opposite side. A circuit structure according to any one of claims 8 to 10, and a case for accommodating the circuit structure inside,
An opening is formed in the case, and the prepreg of the circuit board is exposed from the opening, and the prepreg also serves as the case.

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