JP2004146497A - Printed board connecting method and composite printed board - Google Patents

Printed board connecting method and composite printed board Download PDF

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Publication number
JP2004146497A
JP2004146497A JP2002308170A JP2002308170A JP2004146497A JP 2004146497 A JP2004146497 A JP 2004146497A JP 2002308170 A JP2002308170 A JP 2002308170A JP 2002308170 A JP2002308170 A JP 2002308170A JP 2004146497 A JP2004146497 A JP 2004146497A
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printed board
circuit layer
layer
hole
board
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JP2002308170A
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JP4190857B2 (en
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Mitsuhiro Nakao
中尾　光宏
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Fujikura Ltd
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Fujikura Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To connect a flexible printed board and a rigid printed board without using a connector. <P>SOLUTION: A conductor bump 20 having a large-diameter swollen section 22 at the tip of its small-diameter section 21 is provided on and protrudes from the surface of the circuit layer 12 of a flexible printed board 10. A recessed hole 50 is provided in a rigid printed board 30, wherein a through hole 51 positioned in a wiring layer 42 and corresponding to the small-diameter section 21 and a cavity 52 positioned in an insulating layer 41 and corresponding to the swollen section 22 communicate with each other. The conductor bump 20 is pressed into the recessed hole 50 for the establishment of electric connection between the circuit layer 12 of the flexible printed board 10 and the circuit layer 42 of the rigid printed board 30. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、プリント基板の接続方法と、接続された複合プリント基板に関するものである。
【０００２】
【従来の技術】
一般に、パソコンやＤＶＤ（デジタル多用途ディスク）プレーヤなど精密家電機器の部品として、柔軟性のあるＦＰＣ（フレキシブルプリント基板）と、ＣＣＬ（銅貼り積層板）を複数枚貼り合わせた剛性のあるＲＰＣ（リジッドプリント基板）とを組み合わせた複合プリント基板が広く利用されている。
【０００３】
この種の複合プリント基板を構成するため、従来は、図７に示すようにコネクタを用いてＦＰＣとＲＰＣとを接続していた。すなわち、ＲＰＣにコネクタを実装し、このコネクタにＦＰＣを差し込み固定することで、ＦＰＣの回路層とＲＰＣの回路層とを電気的に接続していた。
【０００４】
【非特許文献１】
沼倉研史著「高密度フレキシブル基板入門」図４．１８
【０００５】
【発明が解決しようとする課題】
しかしながら、このような従来のものは、コネクタを用いてＦＰＣとＲＰＣとを接続するため、ＦＰＣおよびＲＰＣのスペース以外に、コネクタ部品が占めるスペースが必要であり、そのため、小型化・高密度化の妨げとなるだけでなく、コネクタ部品自体のコストが余分に必要となるという問題があった。
【０００６】
この発明の課題は、上記従来のもののもつ問題点を排除して、コネクタを用いずに、フレキシブルプリント基板とリジッドプリント基板とを接続することができ、それにより、小型化およびコスト削減を実現することのできるプリント基板の接続方法および複合プリント基板を提供することにある。
【０００７】
【課題を解決するための手段】
この発明は上記課題を解決するものであって、請求項１に係る発明は、フレキシブルプリント基板とリジッドプリント基板とを接続する方法であって、前記フレキシブルプリント基板の回路層表面に、小径部の先に大径の膨張部を有する導体バンプを突設し、前記リジッドプリント基板に、回路層に位置して前記小径部に対応する貫通孔と、絶縁層に位置して前記膨張部に対応する凹所とが連通した凸形穴を穿設し、前記導体バンプを前記凸形穴に押し込むことで、フレキシブルプリント基板の前記回路層とリジッドプリント基板の前記回路層とを電気的に接続するプリント基板の接続方法である。
【０００８】
請求項２に係る発明は、請求項１記載の発明において、前記導体バンプの膨張部の高さと、前記凸形穴の凹所の深さとをほぼ等しく形成するプリント基板の接続方法である。
【０００９】
請求項３に係る発明は、請求項１または請求項２記載の発明において、前記導体バンプの膨張部の表面に半田メッキを施し、前記導体バンプを前記凸形穴に押し込んだのち、リフロー処理することで、前記半田メッキが溶融して導体バンプとリジッドプリント基板の前記回路層とを金属結合するプリント基板の接続方法である。
【００１０】
請求項４に係る発明は、回路層表面に、小径部の先に大径の膨張部を有する導体バンプを突設してなるフレキシブルプリント基板と、回路層に位置して前記小径部に対応する貫通孔と、絶縁層に位置して前記膨張部に対応する凹所とが連通した凸形穴を穿設してなるリジッドプリント基板とで構成され、前記導体バンプを前記凸形穴に押し込むことで、フレキシブルプリント基板の前記回路層とリジッドプリント基板の前記回路層とを電気的に接続した複合プリント基板である。
【００１１】
【発明の実施の形態】
この発明の実施の形態を、図面を参照して説明する。
図１は、この発明による複合プリント基板の一実施の形態を示す断面図であり、この複合プリント基板１は、ＦＰＣ（フレキシブルプリント基板）１０と、ＣＣＬ（銅貼り積層板）を複数枚貼り合わせたＲＰＣ（リジッドプリント基板）３０とで構成されるものである。
【００１２】
ＦＰＣ（フレキシブルプリント基板）１０は、図２（ａ）に示すように、ＰＩ（ポリイミド）等の樹脂をベースフィルムとする絶縁体からなる絶縁層１１の片面に、エポキシ系の接着剤を用いて銅箔を貼り付けて所要の回路層（回路パターン）１２を形成したものであり、回路層１２の表面には、ＲＰＣ３０との接続に適した位置に、小径部２１の先に大径の膨張部２２を有する導体バンプ２０が突設されている。
【００１３】
一方、ＲＰＣ（リジッドプリント基板）３０は、図２（ｂ）に示すように、最上層ＣＣＬ（銅貼り積層板）４０と、それ以下（２層目ＣＣＬ６０のみ図示し、他は図示省略）のＣＣＬ（銅貼り積層板）とを貼り合わせたものである。
【００１４】
最上層ＣＣＬ４０は、ＰＩ（ポリイミド）等の樹脂をベースフィルムとする絶縁体からなる絶縁層４１の片面に、エポキシ系の接着剤を用いて銅箔を貼り付けて所要の回路層（回路パターン）４２を形成したものであり、ＦＰＣ１０との接続に適した位置に、回路層４２にあって小径部２１に対応する貫通孔５１と、絶縁層４１にあって膨張部２２に対応する凹所５２とが連通した凸形穴５０が穿設されている。
【００１５】
また、２層目ＣＣＬ６０は、ガラスエポキシ等の樹脂をベースフィルムとする絶縁体からなる絶縁層６１の少なくとも片面に、エポキシ系の接着剤を用いて銅箔を貼り付けて所要の回路層（回路パターン）６２を形成したものであり、この２層目ＣＣＬ６０の上面に、例えばエポキシ系の接着シート６３を用いて最上層ＣＣＬ４０を貼り合わせることで、ＲＰＣ（リジッドプリント基板）３０が構成されるものである。
【００１６】
ＦＰＣ１０の導体バンプ２０は、図３に示すようにして形成することができる。すなわち、まず、図３（ａ）に示すように、回路層１２の表面に液状レジストを印刷法により塗布することで、レジスト１３を形成するとともに、所定のバンプ形成位置に小径部２１を形成するための開口１４を設けておく。このレジスト１３の厚さは、ＲＰＣ３０の最上層ＣＣＬ４０の回路層４２の厚さにほぼ等しく形成することができるが、これより幾分薄くても厚くてもよい。
【００１７】
つぎに、図３（ｂ）に示すように、このＦＰＣ１０の開口１４に、ＣｕまたはＮｉメッキをドーム状になるまで行なうことで、開口１４内に小径部２１が形成されるとともに、その上方に大径の膨張部２２が形成され、全体がきのこ状の導体バンプ２０となる。このとき、膨張部２２の高さが、ＲＰＣ３０の凸形穴５０の凹所５２の深さにほぼ等しく形成されるように、ＣｕまたはＮｉメッキの工程を調節する。
【００１８】
さらに、図３（ｃ）に示すように、導体バンプ２０の表面に半田メッキ２３を施したのち、図３（ｄ）に示すように、レジスト１３を除去することで、表面に半田メッキ２３が施された導体バンプ２０が形成される。
【００１９】
したがって、表面に半田メッキ２３が施された導体バンプ２０は、開口１４の内部で形成された小径部２１と、小径部２１の上方に形成された大径の膨張部２２とで構成され、小径部２１の高さは、ＲＰＣ３０の凸形穴５０の貫通孔５１の高さにほぼ等しく形成され、また、膨張部２２の高さは、ＲＰＣ３０の凸形穴５０の凹所５２の深さにほぼ等しく形成されることとなる。
【００２０】
一方、ＲＰＣ３０の凸形穴５０は、図４に示すようにして形成することができる。これは、最上層ＣＣＬ４０がまだ２層目ＣＣＬ６０の上面に貼り合わされていない場合である。この場合、図４（ａ）に示すように、最上層ＣＣＬ４０の回路層４２の接続に適した位置には、回路パターンを形成する際に同時に形成された貫通孔５１が設けられている。
【００２１】
この最上層ＣＣＬ４０の貫通孔５１に相当する位置において、絶縁層４１側からレーザ加工または機械加工を行なうことで絶縁層４１を削り取り、図４（ｂ）に示すように、貫通孔５１と連通した凹所５２を形成する。このとき凹所５２は、まだ底がないから、貫通した孔の状態である。
【００２２】
つぎに、このような最上層ＣＣＬ４０の絶縁層４１側を、図４（ｃ）に示すような２層目ＣＣＬ６０の上面に接着シート６３を用いて貼り合わせることで、図４（ｄ）に示すように、ＲＰＣ３０として一体化される。これにより、凹所５２は接着シート６３によって底が塞がれて凹所となり、凸形穴５０が形成されることとなる。
【００２３】
凸形穴５０はまた、図５に示すようにして形成することができる。これは、最上層ＣＣＬ４０がすでに２層目ＣＣＬ６０の上面に貼り合わされて、ＲＰＣ３０として一体化されている場合である。この場合も、図５（ａ）に示すように、最上層ＣＣＬ４０の回路層４２の接続に適した位置には、回路パターンを形成する際に同時に形成された貫通孔５１が設けられている。
【００２４】
この最上層ＣＣＬ４０の貫通孔５１の位置において、回路層４２側からレーザ加工または機械加工を行なうことで絶縁層４１を削り取る。図５（ｂ）は加工の途中の状態を模式的に示す。
【００２５】
そして、この加工中に、絶縁層４１のみを削り取るようにレーザ加工または機械加工による加工条件を調節することで、図５（ｃ）に示すように、貫通孔５１と連通した凹所５２を形成する。これにより、凸形穴５０が形成されることとなる。
【００２６】
凸形穴５０はさらに、図６に示すようにして形成することができる。これも、最上層ＣＣＬ４０がすでに２層目ＣＣＬ６０の上面に貼り合わされて、ＲＰＣ３０として一体化されている場合である。この場合も、図６（ａ）に示すように、最上層ＣＣＬ４０の回路層４２の接続に適した位置には、回路パターンを形成する際に同時に形成された貫通孔５１が設けられている。
【００２７】
この最上層ＣＣＬ４０の貫通孔５１の位置において、回路層４２側からプラズマエッチングまたはケミカルエッチングを行なうことで絶縁層４１を削り取る。図６（ｂ）は加工の途中の状態を模式的に示す。
【００２８】
そして、この加工中に、絶縁層４１のみを削り取るようにレーザ加工または機械加工による加工条件を調節することで、図５（ｃ）に示すように、貫通孔５１と連通した凹所５２を形成する。これにより、凸形穴５０が形成されることとなる。
【００２９】
この場合は、絶縁層４１の材質（ポリイミド）と接着シート６３の材質（エポキシ系）とが相違しているから、プラズマエッチングまたはケミカルエッチングをポリイミド層に選択的に反応させることで、絶縁層４１のみを削り取ることができる。そのため、図６（ｃ）に示すように、貫通孔５１と連通した凹所５２を形成することができ、これにより、凸形穴５０が形成されることとなる。
【００３０】
次に、上記の複合プリント基板１を構成するため、ＦＰＣ１０とＲＰＣ３０とを接続する方法について説明する。
【００３１】
図１、図２に示すように、まず、ＦＰＣ１０に形成した導体バンプ２０を、ＲＰＣ３０に形成した凸形穴５０に押し込む。すると、導体バンプ２０の膨張部２２が凸形穴５０の凹所５２に嵌まり込み、この状態が機械的に維持される。このとき、膨張部２２の高さが凹所５２の深さにほぼ等しいことから、膨張部２２の張り出し部上縁（図１）が貫通孔５１の周囲の回路層４２下面（図１）に接触または圧接し、また、小径部２１の高さが貫通孔５１の高さにほぼ等しいことから、貫通孔５１の周囲の回路層４２上面（図１）が回路層１２に接触または圧接する。これにより、ＦＰＣ１０の回路層１２とＲＰＣ３０の最上層ＣＣＬ４０の回路層４２とが、電気的に接続された状態に保持され、複合プリント基板１が構成されることとなる。
【００３２】
また、導体バンプ２０を凸形穴５０に押し込んだのちリフロー処理することで、膨張部２２の表面に施してある半田メッキ２３が溶融して、導体バンプ２０とＲＰＣ３０の回路層４２とを金属結合することができる。この場合、図１に示すものを上下反転した状態でリフロー処理すると、溶融した半田が膨張部２２の張り出し部から流れ落ちることで、導体バンプ２０と貫通孔５１の周囲の回路層４２との金属結合が確実に行われる。これにより、ＦＰＣ１０とＲＰＣ３０との電気的接続がいっそう確実となり、複合プリント基板１として高い信頼性が発揮できる。
【００３３】
なお、上記の実施の形態では、導体バンプ２０および凸形穴５０を１個ずつしか図示してないが、これに限定するものでなく、ＦＰＣ１０とＲＰＣ３０との接続に適した位置に、任意の個数ずつ設けて接続に用いることが可能である。
【００３４】
また、上記の実施の形態では、ＣＬ（カバーレイヤ）について記載してないが、ＦＰＣ１０の回路層１２の表面や、ＲＰＣ３０の最上層ＣＣＬ４０の回路層４２の表面には、導体バンプ２０を凸形穴５０に押し込むことで電気的接続を図る所定の接続箇所を除いて、必要な部分に、例えば、ＰＩ（ポリイミド）等の樹脂をベースフィルムとする絶縁体からなるＣＬ（カバーレイヤ）を貼り付けることはいうまでもない。
【００３５】
さらに、例えば図２（ａ）に示すようなＦＰＣ１０と、例えば図４（ｂ）に示すような最上層ＣＣＬ４０（すなわちＦＰＣ）とを、導体バンプ２０と凸形穴５０とを嵌め合いながら何層も貼り合わせていくことで、多層積層されたＲＰＣを作り上げることも可能である。
【００３６】
【発明の効果】
この発明は以上のように、フレキシブルプリント基板の回路層表面に、小径部の先に大径の膨張部を有する導体バンプを突設し、リジッドプリント基板に、回路層に位置して前記小径部に対応する貫通孔と、絶縁層に位置して前記膨張部に対応する凹所とが連通した凸形穴を穿設し、前記導体バンプを前記凸形穴に押し込むことで、フレキシブルプリント基板の前記回路層とリジッドプリント基板の前記回路層とを電気的に接続するように構成したので、コネクタを用いずに、フレキシブルプリント基板とリジッドプリント基板とを接続することができ、そのため、コネクタ部品の占めるスペースが不要となって小型化・高密度化を実現することができ、また、コネクタ部品のコストが不要となってコスト削減を実現することができる効果がある。
【図面の簡単な説明】
【図１】この発明による複合プリント基板の一実施の形態を示す要部の断面図である。
【図２】図１の複合プリント基板の接続前の状態を示す断面図である。
【図３】図１の複合プリント基板に用いるフレキシブルプリント基板に導体バンプを形成する方法を示す説明図である。
【図４】図１の複合プリント基板に用いるリジッドプリント基板に凸形穴を形成する方法の一例を示す説明図である。
【図５】図１の複合プリント基板に用いるリジッドプリント基板に凸形穴を形成する方法の他の例を示す説明図である。
【図６】図１の複合プリント基板に用いるリジッドプリント基板に凸形穴を形成する方法のさらに他の例を示す説明図である。
【図７】従来の複合プリント基板の一例を示す断面図である。
【符号の説明】
１　複合プリント基板
１０　ＦＰＣ（フレキシブルプリント基板）
１１、４１、６１　絶縁層
１２、４２、６２　回路層（回路パターン）
１３　レジスト
１４　開口
２０　導体バンプ
２１　小径部
２２　膨張部
２３　半田メッキ
３０　ＲＰＣ（リジッドプリント基板）
４０　最上層ＣＣＬ（銅貼り積層板）
５０　凸形穴
５１　貫通孔
５２　凹所
６０　２層目ＣＣＬ（銅貼り積層板）
６３　接着シート[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for connecting printed circuit boards and a connected composite printed circuit board.
[0002]
[Prior art]
Generally, as parts of precision home appliances such as personal computers and DVD (digital versatile disc) players, rigid RPC (flexible printed circuit board) and rigid RPC (multilayer copper-clad laminate) are bonded together. Rigid printed circuit boards) are widely used.
[0003]
In order to construct this type of composite printed circuit board, conventionally, an FPC and an RPC are connected using a connector as shown in FIG. That is, a connector is mounted on the RPC, and the FPC is inserted into and fixed to the connector, thereby electrically connecting the circuit layer of the FPC and the circuit layer of the RPC.
[0004]
[Non-patent document 1]
Kenshi Numakura, "Introduction to High Density Flexible Substrates" Figure 4.18
[0005]
[Problems to be solved by the invention]
However, such a conventional device requires a space occupied by connector components in addition to the space for the FPC and the RPC because the FPC and the RPC are connected using a connector. In addition to hindrance, there is a problem that extra cost for the connector component itself is required.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems of the related art and to connect a flexible printed board and a rigid printed board without using a connector, thereby realizing miniaturization and cost reduction. It is an object of the present invention to provide a printed circuit board connecting method and a composite printed circuit board that can be used.
[0007]
[Means for Solving the Problems]
The present invention solves the above problems, and the invention according to claim 1 is a method for connecting a flexible printed board and a rigid printed board, wherein a small diameter portion is provided on a surface of a circuit layer of the flexible printed board. First, a conductive bump having a large-diameter inflated portion is protruded, and a through-hole corresponding to the small-diameter portion located in a circuit layer and a corresponding to the inflated portion located in an insulating layer are provided on the rigid printed circuit board. A print for electrically connecting the circuit layer of a flexible printed circuit board and the circuit layer of a rigid printed circuit board by forming a convex hole communicating with the recess and pressing the conductor bump into the convex hole. This is a method of connecting substrates.
[0008]
According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a method for connecting printed circuit boards, wherein the height of the expanded portion of the conductor bump is substantially equal to the depth of the recess of the convex hole.
[0009]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the surface of the expanded portion of the conductor bump is subjected to solder plating, and the conductor bump is pressed into the convex hole and then subjected to a reflow process. In this case, the solder plating is melted to connect the conductor bumps and the circuit layer of the rigid printed board with a metal.
[0010]
According to a fourth aspect of the present invention, a flexible printed circuit board having a conductive bump having a large-diameter inflated portion at the tip of a small-diameter portion is provided on a surface of a circuit layer, and corresponds to the small-diameter portion located on a circuit layer. A through hole, and a rigid printed circuit board formed by forming a convex hole in which a concave portion corresponding to the inflatable portion is located in the insulating layer and communicates, and pressing the conductor bump into the convex hole. And a composite printed circuit board in which the circuit layer of the flexible printed circuit board and the circuit layer of the rigid printed circuit board are electrically connected.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of a composite printed circuit board according to the present invention. This composite printed circuit board 1 has an FPC (flexible printed circuit board) 10 and a plurality of CCLs (copper-laminated boards). RPC (rigid printed circuit board) 30.
[0012]
As shown in FIG. 2A, an FPC (flexible printed circuit board) 10 is formed by using an epoxy-based adhesive on one surface of an insulating layer 11 made of an insulator having a resin such as PI (polyimide) as a base film. A required circuit layer (circuit pattern) 12 is formed by pasting a copper foil, and a large-diameter expansion is provided on the surface of the circuit layer 12 at a position suitable for connection with the RPC 30 before the small-diameter portion 21. A conductive bump 20 having a portion 22 is provided so as to protrude.
[0013]
On the other hand, as shown in FIG. 2B, the RPC (rigid printed circuit board) 30 has an uppermost layer CCL (copper-laminated laminate) 40 and a lower layer CCL (copper-laminated laminate) 40 or less (only the second layer CCL 60 is shown, and the others are omitted). CCL (copper-laminated laminate).
[0014]
The uppermost layer CCL 40 is formed by attaching a copper foil to one surface of an insulating layer 41 made of an insulator having a resin such as PI (polyimide) as a base film using an epoxy-based adhesive, and forming a required circuit layer (circuit pattern). 42, a through hole 51 in the circuit layer 42 corresponding to the small-diameter portion 21 and a recess 52 in the insulating layer 41 corresponding to the expansion portion 22 at positions suitable for connection with the FPC 10. Is formed in a convex hole 50 communicating with.
[0015]
The second layer CCL 60 is formed by attaching a copper foil to at least one surface of an insulating layer 61 made of an insulator having a resin such as glass epoxy as a base film by using an epoxy-based adhesive, and forming a required circuit layer (circuit). Pattern) 62, and the uppermost layer CCL 40 is attached to the upper surface of the second layer CCL 60 using, for example, an epoxy-based adhesive sheet 63, thereby forming an RPC (rigid printed circuit board) 30. It is.
[0016]
The conductor bumps 20 of the FPC 10 can be formed as shown in FIG. That is, first, as shown in FIG. 3A, a liquid resist is applied to the surface of the circuit layer 12 by a printing method, thereby forming the resist 13 and forming the small-diameter portion 21 at a predetermined bump formation position. Opening 14 is provided. The thickness of the resist 13 can be substantially equal to the thickness of the circuit layer 42 of the uppermost layer CCL 40 of the RPC 30, but may be somewhat thinner or thicker.
[0017]
Next, as shown in FIG. 3B, by performing Cu or Ni plating on the opening 14 of the FPC 10 until it becomes dome-shaped, a small-diameter portion 21 is formed in the opening 14 and is formed above the opening. A large-diameter inflatable portion 22 is formed, and the whole becomes the mushroom-shaped conductor bump 20. At this time, the Cu or Ni plating process is adjusted so that the height of the expansion portion 22 is formed substantially equal to the depth of the concave portion 52 of the convex hole 50 of the RPC 30.
[0018]
Further, as shown in FIG. 3C, the surface of the conductor bump 20 is subjected to solder plating 23, and then, as shown in FIG. The applied conductor bump 20 is formed.
[0019]
Therefore, the conductor bump 20 having the surface plated with the solder plating 23 is composed of the small-diameter portion 21 formed inside the opening 14 and the large-diameter expansion portion 22 formed above the small-diameter portion 21. The height of the portion 21 is formed substantially equal to the height of the through hole 51 of the convex hole 50 of the RPC 30, and the height of the expansion portion 22 is set to the depth of the concave portion 52 of the convex hole 50 of the RPC 30. They will be formed almost equally.
[0020]
On the other hand, the convex hole 50 of the RPC 30 can be formed as shown in FIG. This is a case where the uppermost layer CCL 40 has not been bonded to the upper surface of the second layer CCL 60 yet. In this case, as shown in FIG. 4A, a through hole 51 formed at the same time as forming a circuit pattern is provided at a position suitable for connection of the circuit layer 42 of the uppermost layer CCL 40.
[0021]
At a position corresponding to the through hole 51 of the uppermost layer CCL 40, the insulating layer 41 was scraped off by performing laser processing or mechanical processing from the insulating layer 41 side, and communicated with the through hole 51 as shown in FIG. A recess 52 is formed. At this time, since the recess 52 has no bottom yet, it is in a state of a through hole.
[0022]
Next, the insulating layer 41 side of the uppermost layer CCL 40 is bonded to the upper surface of the second layer CCL 60 as shown in FIG. As described above, the RPC 30 is integrated. As a result, the bottom of the recess 52 is closed by the adhesive sheet 63 to form a recess, and the convex hole 50 is formed.
[0023]
The convex hole 50 can also be formed as shown in FIG. This is a case where the uppermost layer CCL 40 is already bonded to the upper surface of the second layer CCL 60 and integrated as the RPC 30. Also in this case, as shown in FIG. 5A, a through hole 51 formed at the same time as forming a circuit pattern is provided at a position suitable for connection of the circuit layer 42 of the uppermost layer CCL 40.
[0024]
At the position of the through hole 51 of the uppermost layer CCL 40, the insulating layer 41 is scraped off by performing laser processing or mechanical processing from the circuit layer 42 side. FIG. 5B schematically shows a state during the processing.
[0025]
Then, during this processing, the recess 52 communicating with the through hole 51 is formed by adjusting the processing conditions by laser processing or mechanical processing so that only the insulating layer 41 is scraped off, as shown in FIG. I do. As a result, a convex hole 50 is formed.
[0026]
The convex hole 50 can be further formed as shown in FIG. This is also the case where the uppermost layer CCL 40 is already bonded to the upper surface of the second layer CCL 60 and integrated as the RPC 30. Also in this case, as shown in FIG. 6A, a through hole 51 formed at the same time as forming a circuit pattern is provided at a position suitable for connection of the circuit layer 42 of the uppermost layer CCL 40.
[0027]
At the position of the through hole 51 in the uppermost layer CCL 40, the insulating layer 41 is scraped off by performing plasma etching or chemical etching from the circuit layer 42 side. FIG. 6B schematically shows a state during the processing.
[0028]
Then, during this processing, the recess 52 communicating with the through hole 51 is formed by adjusting the processing conditions by laser processing or mechanical processing so that only the insulating layer 41 is scraped off, as shown in FIG. I do. As a result, a convex hole 50 is formed.
[0029]
In this case, since the material of the insulating layer 41 (polyimide) and the material of the adhesive sheet 63 (epoxy) are different, the insulating layer 41 is selectively reacted with the plasma etching or the chemical etching to the polyimide layer. Only can be scraped. Therefore, as shown in FIG. 6C, a recess 52 communicating with the through-hole 51 can be formed, thereby forming a convex hole 50.
[0030]
Next, a method of connecting the FPC 10 and the RPC 30 to configure the composite printed circuit board 1 will be described.
[0031]
As shown in FIGS. 1 and 2, first, the conductor bumps 20 formed on the FPC 10 are pressed into the convex holes 50 formed on the RPC 30. Then, the expanded portion 22 of the conductor bump 20 fits into the recess 52 of the convex hole 50, and this state is mechanically maintained. At this time, since the height of the expanding portion 22 is substantially equal to the depth of the concave portion 52, the upper edge of the projecting portion of the expanding portion 22 (FIG. 1) is formed on the lower surface of the circuit layer 42 around the through hole 51 (FIG. The upper surface of the circuit layer 42 surrounding the through hole 51 (FIG. 1) comes into contact with or presses against the circuit layer 12 because the small diameter portion 21 is approximately equal to the height of the through hole 51. As a result, the circuit layer 12 of the FPC 10 and the circuit layer 42 of the uppermost CCL 40 of the RPC 30 are maintained in an electrically connected state, and the composite printed circuit board 1 is configured.
[0032]
Further, the solder bumps 23 applied to the surface of the expansion portion 22 are melted by pressing the conductor bumps 20 into the convex holes 50 and then performing a reflow process, so that the conductor bumps 20 and the circuit layer 42 of the RPC 30 are metal-bonded. can do. In this case, when the reflow process is performed in a state where the one shown in FIG. Is performed reliably. As a result, the electrical connection between the FPC 10 and the RPC 30 is further ensured, and high reliability as the composite printed circuit board 1 can be exhibited.
[0033]
In the above-described embodiment, only one conductor bump 20 and one convex hole 50 are shown, but the present invention is not limited to this, and an arbitrary position is suitable for connection between the FPC 10 and the RPC 30. It is possible to provide a number of them and use them for connection.
[0034]
Further, in the above embodiment, although the CL (cover layer) is not described, the conductor bump 20 is formed in a convex shape on the surface of the circuit layer 12 of the FPC 10 and the surface of the circuit layer 42 of the uppermost CCL 40 of the RPC 30. A CL (cover layer) made of an insulator having a resin such as PI (polyimide) as a base film is adhered to a necessary portion except for a predetermined connection portion which is to be electrically connected by being pushed into the hole 50. Needless to say.
[0035]
Further, for example, the FPC 10 as shown in FIG. 2A and the uppermost layer CCL 40 (ie, FPC) as shown in FIG. It is also possible to make a multilayer laminated RPC by bonding together.
[0036]
【The invention's effect】
As described above, according to the present invention, a conductor bump having a large-diameter inflated portion is projected from a small-diameter portion on the surface of a circuit layer of a flexible printed board, and the small-diameter portion is positioned on a circuit layer on a rigid printed board. A through-hole corresponding to the above, a concave hole located in the insulating layer and communicating with the concave portion corresponding to the inflated portion is formed, and the conductor bump is pushed into the convex hole, whereby a flexible printed circuit board is formed. Since the circuit layer and the circuit layer of the rigid printed board are configured to be electrically connected to each other, it is possible to connect the flexible printed board and the rigid printed board without using a connector. The space occupied is not required, so that miniaturization and high density can be realized. In addition, the cost of connector parts is unnecessary, and the cost can be reduced. That.
[Brief description of the drawings]
FIG. 1 is a sectional view of a main part showing an embodiment of a composite printed circuit board according to the present invention.
FIG. 2 is a sectional view showing a state before connection of the composite printed circuit board of FIG. 1;
FIG. 3 is an explanatory view showing a method of forming a conductive bump on a flexible printed board used for the composite printed board of FIG. 1;
FIG. 4 is an explanatory view showing an example of a method of forming a convex hole in a rigid printed board used for the composite printed board of FIG. 1;
FIG. 5 is an explanatory view showing another example of a method for forming a convex hole in a rigid printed board used for the composite printed board of FIG. 1;
FIG. 6 is an explanatory view showing still another example of a method for forming a convex hole in a rigid printed board used for the composite printed board of FIG. 1;
FIG. 7 is a cross-sectional view illustrating an example of a conventional composite printed circuit board.
[Explanation of symbols]
1 Composite Printed Circuit Board 10 FPC (Flexible Printed Circuit Board)
11, 41, 61 Insulating layer 12, 42, 62 Circuit layer (circuit pattern)
13 Resist 14 Opening 20 Conductor bump 21 Small diameter part 22 Expansion part 23 Solder plating 30 RPC (rigid printed circuit board)
40 Top layer CCL (Copper laminated board)
50 Convex hole 51 Through hole 52 Concavity 60 Second layer CCL (Copper laminated board)
63 adhesive sheet

Claims (4)

フレキシブルプリント基板とリジッドプリント基板とを接続する方法であって、
前記フレキシブルプリント基板の回路層表面に、小径部の先に大径の膨張部を有する導体バンプを突設し、
前記リジッドプリント基板に、回路層に位置して前記小径部に対応する貫通孔と、絶縁層に位置して前記膨張部に対応する凹所とが連通した凸形穴を穿設し、
前記導体バンプを前記凸形穴に押し込むことで、フレキシブルプリント基板の前記回路層とリジッドプリント基板の前記回路層とを電気的に接続する、
ことを特徴とするプリント基板の接続方法。A method for connecting a flexible printed board and a rigid printed board,
On the surface of the circuit layer of the flexible printed circuit board, projecting conductor bumps having a large-diameter inflated portion ahead of the small-diameter portion,
In the rigid printed circuit board, a through-hole corresponding to the small-diameter portion located in the circuit layer, and a convex hole in which a recess corresponding to the inflatable portion is located in the insulating layer communicated,
By pressing the conductor bumps into the convex holes, the circuit layer of the flexible printed board and the circuit layer of the rigid printed board are electrically connected,
A method of connecting printed circuit boards, characterized in that: 前記導体バンプの膨張部の高さと、前記凸形穴の凹所の深さとをほぼ等しく形成することを特徴とする請求項１記載のプリント基板の接続方法。2. The method according to claim 1, wherein the height of the expanded portion of the conductor bump is substantially equal to the depth of the recess of the convex hole. 前記導体バンプの膨張部の表面に半田メッキを施し、
前記導体バンプを前記凸形穴に押し込んだのち、リフロー処理することで、前記半田メッキが溶融して導体バンプとリジッドプリント基板の前記回路層とを金属結合する、
ことを特徴とする請求項１または請求項２記載のプリント基板の接続方法。Applying solder plating to the surface of the expanded portion of the conductor bump,
After the conductor bumps are pushed into the convex holes, by performing a reflow process, the solder plating is melted and the conductor bumps and the circuit layer of the rigid printed board are metal-bonded,
The method for connecting printed circuit boards according to claim 1 or 2, wherein: 回路層表面に、小径部の先に大径の膨張部を有する導体バンプを突設してなるフレキシブルプリント基板と、
回路層に位置して前記小径部に対応する貫通孔と、絶縁層に位置して前記膨張部に対応する凹所とが連通した凸形穴を穿設してなるリジッドプリント基板とで構成され、
前記導体バンプを前記凸形穴に押し込むことで、フレキシブルプリント基板の前記回路層とリジッドプリント基板の前記回路層とを電気的に接続した、
ことを特徴とする複合プリント基板。On the surface of the circuit layer, a flexible printed board formed by projecting conductive bumps having a large-diameter inflated portion before the small-diameter portion,
A rigid printed board formed with a through hole corresponding to the small-diameter portion located on the circuit layer and a convex hole communicating with a recess corresponding to the expansion portion located on the insulating layer. ,
By pressing the conductor bumps into the convex holes, the circuit layer of the flexible printed board and the circuit layer of the rigid printed board were electrically connected,
A composite printed circuit board characterized by the above.
JP2002308170A 2002-10-23 2002-10-23 Printed circuit board connection method and composite printed circuit board Expired - Lifetime JP4190857B2 (en)

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Publication number Priority date Publication date Assignee Title
WO2007132301A1 (en) * 2006-05-15 2007-11-22 Sony Ericsson Mobile Communications Ab Circuit connectors
US7445462B2 (en) 2006-01-03 2008-11-04 Samsung Electronics Co., Ltd Method of connecting signal lines, a printed circuit board assembly and electronic apparatus having the same
CN101459771A (en) * 2007-12-10 2009-06-17 三星Techwin株式会社 Digital photographing apparatus
JP2017502463A (en) * 2013-12-18 2017-01-19 インテリジェント エナジー リミテッドＩｎｔｅｌｌｉｇｅｎｔ Ｅｎｅｒｇｙ Ｌｉｍｉｔｅｄ Connector system for a fuel cell stack assembly
CN115842254A (en) * 2023-03-01 2023-03-24 上海合见工业软件集团有限公司 Stacking interconnection system and circuit board

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JPH0685423A (en) * 1992-02-24 1994-03-25 Internatl Business Mach Corp <Ibm> Electric assembly
JPH10501367A (en) * 1994-06-07 1998-02-03 テセラ，インコーポレイテッド Microelectronic contacts and assemblies

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Publication number Priority date Publication date Assignee Title
JPH0685423A (en) * 1992-02-24 1994-03-25 Internatl Business Mach Corp <Ibm> Electric assembly
JPH10501367A (en) * 1994-06-07 1998-02-03 テセラ，インコーポレイテッド Microelectronic contacts and assemblies

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7445462B2 (en) 2006-01-03 2008-11-04 Samsung Electronics Co., Ltd Method of connecting signal lines, a printed circuit board assembly and electronic apparatus having the same
WO2007132301A1 (en) * 2006-05-15 2007-11-22 Sony Ericsson Mobile Communications Ab Circuit connectors
US7442046B2 (en) 2006-05-15 2008-10-28 Sony Ericsson Mobile Communications Ab Flexible circuit connectors
CN101459771A (en) * 2007-12-10 2009-06-17 三星Techwin株式会社 Digital photographing apparatus
JP2017502463A (en) * 2013-12-18 2017-01-19 インテリジェント エナジー リミテッドＩｎｔｅｌｌｉｇｅｎｔ Ｅｎｅｒｇｙ Ｌｉｍｉｔｅｄ Connector system for a fuel cell stack assembly
US10186719B2 (en) 2013-12-18 2019-01-22 Intelligent Energy Limited Connector system for a fuel cell stack assembly
CN115842254A (en) * 2023-03-01 2023-03-24 上海合见工业软件集团有限公司 Stacking interconnection system and circuit board

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