JP2004335844A

JP2004335844A - Circuit board device and method for manufacturing the same

Info

Publication number: JP2004335844A
Application number: JP2003131487A
Authority: JP
Inventors: Atsuya Sato; 淳哉佐藤; Yukio Yamaguchi; 幸雄山口
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2003-05-09
Filing date: 2003-05-09
Publication date: 2004-11-25

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for achieving electrical connection in a dense and inexpensive way between the electrode patterns of a pair of printed circuit boards having densely packaged connection terminals, and to provide a circuit board device having printed circuit boards connected by this method. <P>SOLUTION: The circuit board device comprises a first board 101 with a connection terminal 103 formed thereon and a second board 102 with a connection terminal 104 corresponding to the connection terminal 103 formed thereon. In the same plane where the connection terminal 104 of the second board 102 exists, positioning chip members 105a and 105b approximately cubic in shape are accurately positioned on previously formed connection pads, and are then surface-mounted in a reflow soldering process. The first board 101 and the second board 102 are so positioned that their connection terminals 103 and 104 face each other. The first board 101 is fitted into between the positioning chip members surface-mounted on the board 102 for the establishment of electrical connection between their connection terminals 103 and 104. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、回路基板装置およびその製造方法に関し、特に高密度に配置された電極からなる電極パターン（接続端子）を有する一対のプリント配線基板間において、各々の電極パターン（接続端子）同士を電気的に接続するプリント配線基板同士の精密位置決め方法およびその位置決め方法により接続されたプリント配線基板を備えた回路基板装置に関する。
【０００２】
【従来の技術】
従来、携帯電話装置やＰＤＡ（ＰｅｒｓｏｎａｌＤｉｇｉｔａｌＡｓｓｉｓｔａｎｔ）端末、あるいはその他多くの電子機器では、限られたスペースの中に多くの電子部品を実装したプリント配線基板を複数搭載している。近年、特に高機能化・多機能化が進み、多数の接続端子を有した複数のプリント配線基板同士の接続が要求されてきており、電極パターンの狭ピッチ化が進んでいる。これに伴い、プリント配線基板同士の接続端子も狭ピッチ化され、互いの狭ピッチ化された接続端子同士の位置合わせを、容易に且つ精密に行う方法が求められている。
【０００３】
従来のプリント配線基板間同士を位置決めする方法として、図５にピン嵌合を利用した方法、図６に画像認識および画像処理を利用した方法を示す。図５は、ピン嵌合を利用したプリント配線基板間同士を位置決めする方法を示す斜視図である。ここで図５（ａ）はプリント配線基板間同士を位置決めする方法の分解工程斜視図、図５（ｂ）はプリント配線基板間同士を位置決めする方法の組立後斜視図、図５（ｃ）は図５（ｂ）のＡ−Ａ断面模式図である。
【０００４】
先ずプリント配線基板１０１と１０２に互いに対となる接続端子１０３、１０４を形成し、所定の位置に円形もしくは楕円形の位置決め用貫通穴５０１ａ、５０１ｂ、５０２ａ、５０２ｂを打ち抜き加工もしくはドリル加工により形成する。このとき、接続端子１０３と位置決め用貫通穴５０１ａ、５０１ｂとの位置関係は、接続端子１０４と位置決め用貫通穴５０２ａ、５０２ｂとの位置関係と同一である。次に位置決め治具５０３に形成してある位置決め用貫通穴５０１ａ、５０１ｂと５０２ａ、５０２ｂと同一ピッチ、同一直径の位置決め用ピン５０４ａ、５０４ｂと位置決め用貫通穴５０１ａ、５０１ｂ、５０２ａ、５０２ｂとを順次嵌合させることにより、プリント配線基板１０１、１０２上の接続端子１０３、１０４同士の位置合わせが完了する。
【０００５】
図６は、画像認識および画像処理を利用したプリント配線基板間同士を位置決めする方法を示す斜視図である。ここで図６（ａ）はプリント配線基板間同士を位置決めする方法の分解工程斜視図、図６（ｂ）はプリント配線基板間同士を位置決めする方法の組立後斜視図、図６（ｃ）は図６（ｂ）のＡ−Ａ断面模式図である。
【０００６】
先ずプリント配線基板１０１と１０２に互いに対となる接続端子１０３、１０４を形成し、光学的検出装置６０１ａ、６０１ｂにより接続端子１０３、１０４を画像情報として読み取り、相対的な位置関係を図示しない画像解析装置を用いて検出する。次に図示しない部品移動手段により接続端子１０３、１０４の相対的な位置を修正し、プリント配線基板１０１、１０２を順次重ね合わせることにより、接続端子１０３、１０４同士の位置合わせが完了する。
【０００７】
また、従来図７に示すように、配線パターン７０２を形成したプリント配線基板７０１上の円形の位置決め用パターン７０３にハンダを十分に付着させ半球状の突起７０４を形成し、位置決めすべき部品７０５に予め設けられた位置決め用穴７０６を突起７０４に嵌合させてプリント配線基板７０１と部品７０５とを位置合わせする方法が提案されている（例えば、特許文献１参照）。
【０００８】
さらに、従来図８に示すように、接続端子８０２を形成したプリント配線基板８０１上に接続端子と同一材料の嵌合パターン８０３ａ、８０３ｂを形成し、プリント配線基板８０１と接続するプリント配線基板８０４上に形成した接続端子８０５と同一材料で嵌合パターン８０３ａ、８０３ｂと対になる嵌合パターン８０６ａ、８０６ｂを形成し、嵌合パターン８０３ａ、８０６ａおよび８０３ｂ、８０６ｂをそれぞれ嵌合させるようにプリント配線基板８０１、８０４を重ね合わせることにより、接続端子８０２、８０５同士の位置合わせを行う方法が提案されている（例えば、特許文献２参照）。
【０００９】
さらにまた、電極パターン同士を電気的に接続するためのプリント配線基板同士の精密な位置決め方法ではないが、従来ヒートシンク上に複数個の混成集積回路を位置精度良く実装する方法が提案されている。まずセラミック基板上にパワートランジスタやチップコンデンサなどを実装し、クリップを接続して混成集積回路を構成する。チップコンデンサのうち対角部に位置するもの２個を位置決め用部品とする。ヒートシンクに接着剤を塗布し、複数個の混成集積回路を仮搭載する。この後、位置補正用治具を用いて各位置決め用部品の位置を整列状態に揃えるように混成集積回路全体を位置補正し、その後接着剤を硬化させる（例えば、特許文献３参照）。
【００１０】
【特許文献１】
特開平８−３７３９７号公報（〔００１５〕〜〔００１７〕、図１、図２）
【特許文献２】
特開２００１−１２７４２４号公報（〔００２６〕〜〔００３３〕、図１）
【特許文献３】
特開２００１−３１３４９６号公報（〔００４０〕〜〔００４７〕、図１〜図３）
【００１１】
【発明が解決しようとする課題】
先に述べた通り、携帯電話装置やＰＤＡ端末などの電子機器では、限られたスペースの中に多くの電子部品を実装したプリント配線基板を複数枚搭載する必要がある。特に、携帯電話装置やＰＤＡ端末では、接続部の薄型化、省スペース化が非常に重要な要素となる。
【００１２】
ところが、ピン嵌合を利用したプリント配線基板間同士を位置決めする方法を用いた場合、プリント配線基板上には嵌合用ピンを通すための貫通孔を設ける必要があり、この部分が一対のプリント配線基板上のデッドスペースとなり、省スペース化を阻害していた。さらに、別途ピン嵌合用の治工具が必要となるためコストアップ要因となっていた。
【００１３】
また、画像認識および画像処理を利用したプリント配線基板間同士を位置決めする方法を用いた場合、プリント配線基板上のデッドスペースは最小限に抑えることが可能であるが、画像認識を行うための光学的検出装置、プリント配線基板間同士の相対的な位置関係を計算する画像解析装置、プリント配線基板を任意の位置に移動させる部品移動手段が必要となる。一般的に光学的検出装置にはＣＣＤカメラシステムが、画像解析装置にはコンピュータおよび専用の画像解析ソフトウエアが、部品移動手段にはロボットが用いられることが多いため、設備投資に大きな費用がかかり、結果的に製品のコストアップ要因となっていた。
【００１４】
また、特許文献１の場合もピン嵌合を利用したプリント配線基板間同士を位置決めする方法を用いた場合と同様に、プリント配線基板上に嵌合用ハンダ半球および嵌合用ハンダ半球を通すための貫通孔を設ける必要があり、この部分が一対のプリント配線基板上のデッドスペースとなり、省スペース化を阻害していた。
【００１５】
また、特許文献２の場合もピン嵌合を利用したプリント配線基板間同士を位置決めする方法を用いた場合および特許文献１の場合と同様に、プリント配線基板上に嵌合用パターンを設ける必要があり、この部分が一対のプリント配線基板上のデッドスペースとなり、省スペース化を阻害していた。
【００１６】
また、特許文献３の場合は、複数個の混成集積回路を仮搭載した後、位置補正治具を用いて各位置決め用部品の位置を整列状態に揃える工程が必要のため、実装工程が複雑である上、位置補正治具を用いるのでコスト高になるという問題がある。
【００１７】
本発明の目的は、高密度に配置された電極からなる電極パターン（接続端子）を有する一対のプリント配線基板間において、各々の電極パターン（接続端子）同士を電気的に接続するプリント配線基板同士の位置決めを、省スペース化、低コスト化を実現するとともに精確に実施する方法、およびその位置決め方法により接続されたプリント配線基板を備えた回路基板装置を提供することにある。
【００１８】
【課題を解決するための手段】
本発明によれば、接続端子を形成した第一の基板と、第一の基板の接続端子に対応した接続端子を形成した第二の基板と、第二の基板上に表面実装された位置決め用チップ部品とを有し、前記第一の基板と第二の基板の接続端子間の位置決めを第一の基板の外形と前記位置決め用チップ部品との嵌合で行うことを特徴とする位置決め構造を備えた回路基板装置が得られる。位置決め用チップ部品は、チップコンデンサ、チップ抵抗、チップインダクタ、もしくは、位置決め専用に製作した電気的には機能しないダミー部品のいずれかを用い、ハンダリフローによるセルフアライメント効果を利用して精確に位置決めされる。
【００１９】
前記第一および第二の基板としては、多層フレキシブル配線基板、多層リジットプリント配線基板、両面フレキシブル配線基板、両面リジットプリント配線基板、片面フレキシブル配線基板、片面リジットプリント配線基板のうちの１つ以上を使用することができる。前記第一および第二の基板の互いに対応する接続端子同士の電気的接続媒体に、異方性導電部材を用いることもできるし、またハンダまたはＡＣＦまたはＡＣＰまたはＮＣＦまたはＮＣＰを用いることができる。前記位置決め用チップ部品の接合媒体の融点は、前記第一および第二の基板の互いに対応する接続端子同士の電気的接続媒体の融点よりも高いことが望ましい。
【００２０】
また、本発明によれば、接続端子を形成した第２のプリント配線基板上に相対向させて位置決め用チップ部品を実装する工程と、接続端子を形成した第１のプリント配線基板を、双方の接続端子同士が対向するように前記第２のプリント配線基板上の位置決め用チップ部品間に嵌合させ双方の接続端子同士を電気的に接続する工程とを有する回路基板装置の製造方法が得られる。前記第２のプリント配線基板上への位置決め用チップ部品の実装は、第２のプリント配線基板に形成した接続パッド上に位置決め用チップ部品を位置決めして設け、ハンダリフロープロセスにより行う。そして第２のプリント配線基板上の位置決め用チップ部品間に第１のプリント配線基板の外形が嵌合するように構成されている。
【００２１】
本発明によるプリント配線基板間位置決め構造および回路基板装置は、接続端子を形成した第一の基板と、第一の基板の接続端子に対応した接続端子を形成した第二の基板とからなり、さらに、第二の基板の接続端子と同一面に、略直方体形状の位置決め用チップ部品をチップマウンタを用いて予め形成しておいた接続パッド上に精確に位置決めし、ハンダリフロープロセスにより表面実装する。このとき、位置決め用チップ部品はハンダリフロー時のハンダ表面張力によるセルフアライメント効果により、精確に実装される。第一の基板と第二の基板の位置決めは、互いの接続端子を対向させて配置し、第一の基板を第二の基板上に表面実装してある位置決め用チップ部品間に嵌合させて実施する。
【００２２】
【発明の実施の形態】
次に本発明について図面を参照して詳細に説明する。図１は、本発明によるプリント配線基板間同士を位置決めし回路基板装置を製造する方法の一実施形態の斜視図である。ここで図１（ａ）は本発明によるプリント配線基板間同士を位置決めする方法の分解工程斜視図、図１（ｂ）は本発明によるプリント配線基板間同士を位置決めする方法の組立後斜視図、図１（ｃ）は図１（ｂ）のＡ−Ａ断面模式図である。
【００２３】
本発明は、基板裏面（図中下側）に接続端子１０３を形成した第一の基板１０１と、基板表面（図中表面）に接続端子１０３に対応した接続端子１０４を形成した第二の基板１０２とからなり、さらに、第二の基板１０２の接続端子１０４と同一面に、略直方体形状の位置決め用チップ部品１０５ａ、１０５ｂをその外形最短距離が第一の基板１０１のピッチ方向の基板外形と等しくなるよう、図示しないＬＳＩ（大規模集積回路）と同一工程でチップマウンタを用いて予め形成しておいた接続パッド上に精確に位置決めし、ハンダリフロープロセスにより表面実装する。このとき、位置決め用チップ部品１０５ａ、１０５ｂはハンダリフロー時のハンダ表面張力によるセルフアライメント効果により、精確に実装される。
【００２４】
第一の基板１０１と第二の基板１０２の位置決めは、接続端子１０３と接続端子１０４とを互いに対向させて配置し、第一の基板１０１を第二の基板１０２上に表面実装してある位置決め用チップ部品１０５ａ、１０５ｂ間に嵌合させて実施する。この時、接続端子１０３、１０４のピッチ垂直方向（図中前後方向）の位置決めは第一の基板１０１と第二の基板１０２の端部（図中破断線反対側）を突き当てることにより行う。これにより、第一の基板１０１および第二の基板１０２の接続端子１０３、１０４は精確に位置決めされて接触し電気的に接続された回路基板装置を得ることができる。
【００２５】
ここで、接続端子１０３、１０４のピッチ垂直方向（図中前後方向）の位置決めは第一の基板１０１と第二の基板１０２の端部（図中破断線反対側）を突き当てることにより行うが、予め第二の基板１０２の上にピッチ垂直方向位置決め用チップ部品を表面実装することにより実施しても差し支えない。また、位置決め用部品としてチップコンデンサ、チップ抵抗、チップインダクタ、もしくは、位置決め専用に製作した電気的には機能しないダミー部品でも同様の効果が得られ、位置決め用部品の数量も任意に設定しても差し支えない。
【００２６】
なお、上述した第一、第二の基板１０１、１０２の種類としては、フレキシブルプリント配線基板（ＦＰＣ基板）やリジッドプリント配線基板（ＲＰＣ基板）を限定していない。これは第一、第二の基板１０１、１０２に対し、どちらの種類を使用しても実現することができるからである。また、第一および第二の基板としては、多層フレキシブル配線基板、多層リジットプリント配線基板、両面フレキシブル配線基板、両面リジットプリント配線基板、片面フレキシブル配線基板、片面リジットプリント配線基板のいずれも使用することができる。
【００２７】
本発明によれば、高密度に配置された電極からなる電極パターン（接続端子）を有する一対のプリント配線基板間において、各々の電極パターン（接続端子）同士を電気的に接続するプリント配線基板同士の位置決めを、基板上に実装されるＬＳＩ等の実装部品と同一工程上で搭載・リフローされセルフアライメント効果により精確に表面実装された位置決め用チップ部品を利用して行うことにより、精確に且つ簡単に行うことができる回路基板装置およびその製造方法が得られる。
【００２８】
基板上に実装されるＬＳＩ等の実装部品と同一工程上で搭載・リフローされる位置決め用チップ部品の搭載・リフロー技術として、パッド寸法を位置決め用チップ部品外形の＋０．０１ｍｍ〜＋０．０５ｍｍとしたり、ハンダペースト印刷量やリフロー温度プロファイル（加熱温度／速度、加熱保持時間、冷却温度／速度など）を制御することによりセルフアライメント効果を最大限に発揮することができ、精確な搭載を実現できる。ここで、前記パッド寸法は特に高精度位置決めが要求される方向のみに適用すればよく、高精度位置決めの必要ない方向は、前記パッド寸法以外でも問題ない。
【００２９】
また、従来方法で必要だったピン嵌合用貫通孔やアライメントマークにより発生していた基板上のデッドスペースを最小限に抑えることが可能となり、省スペース化が実現できる。さらに、専用の固定・位置決め用治工具や、画像認識を行うための光学的検出装置、プリント配線基板間同士の相対的な位置関係を計算する画像解析装置、プリント配線基板を任意の位置に移動させる部品移動手段（一般的に光学的検出装置にはＣＣＤカメラシステムが、画像解析装置にはコンピュータおよび専用の画像解析ソフトウエアが、部品移動手段にはロボットが用いられることが多い）を必要としないため、低コスト化を実現することができる。
【００３０】
以下、本発明の回路基板構造および基板間の位置決め方法について、具体的な実施例により説明する。
【００３１】
［実施例１］
図２は、本発明の第１の実施例を示している。ここで図２（ａ）は本発明の第１の実施例の分解工程斜視図、図２（ｂ）は本発明の第１の実施例の組立後斜視図、図２（ｃ）は図２（ｂ）のＡ−Ａ断面模式図、図２（ｄ）は図２（ｂ）のＢ−Ｂ断面模式図である。
【００３２】
第一の基板１０１は、ＰＩ（ポリイミド樹脂）を主原料とした可撓性樹脂フィルムである基材とＣｕ配線からなるフレキシブルプリント配線基板（ＦＰＣ基板）で、第一の基板１０１裏面（図中下側）には０．３ｍｍピッチ（配線幅０．１５ｍｍ、配線間隔０．１５ｍｍ）の接続端子１０３を１５本形成してある。第二の基板１０２は、ＦＲ４である基材とＣｕ配線からなるリジッドプリント配線基板（ＲＰＣ基板）で、第二の基板１０２表面（図中上側）には０．３ｍｍピッチ（配線幅０．１５ｍｍ、配線間隔０．１５ｍｍ）の接続端子１０４を１５本形成してある。さらに、第二の基板１０２の接続端子１０４と同一面に、チップコンデンサ２０１ａ、２０１ｂをその外形最短距離が第一の基板１０１のピッチ方向の基板外形と等しくなるよう、図示しないＬＳＩ（大規模集積回路）と同一工程でチップマウンタを用いて予め形成しておいた接続パッド上に精確に位置決めし、ハンダリフロープロセスにより表面実装した。このとき、チップコンデンサ２０１ａ、２０１ｂはハンダリフロー時のハンダ表面張力によるセルフアライメント効果により、位置精度±０．０５０ｍｍ以内で実装され、図示しないＬＳＩとは図示しない配線パターンにより連通している。
【００３３】
第一の基板１０１と第二の基板１０２の位置決めは、接続端子１０３と接続端子１０４とを互いに対向させて配置し、第一の基板１０１を第二の基板１０２上に表面実装してあるチップコンデンサ２０１ａ、２０１ｂ間に嵌合させて実施した。この時、接続端子１０３、１０４のピッチ垂直方向（図中奥行き方向）の位置決めは第一の基板１０１と第二の基板１０２の端部（図中破断線反対側）を突き当てることにより行った。さらに、第一の基板１０１と第二の基板１０２間に、接続端子１０３、１０４に対応して形成されている金属端子２０３が内包されている異方性導電部材２０２を、第一の基板１０１を第二の基板１０２上に表面実装してあるチップコンデンサ２０１ａ、２０１ｂ間に嵌合させて位置決めし、第一の基板１０１と第二の基板１０２の間に挟み込み、加圧部品２０５により上下方向に加圧し電気的に接続して回路基板装置を製造した。
【００３４】
異方性導電部材２０２は、絶縁性エラスチック樹脂材料２０４にゴム硬度５０度（ＪＩＳ−Ｋ−６２４９）のシリコーンゴムを使用し、金属端子２０３には、Ａｕメッキ処理を施した直径φ１２μｍのＳＵＳ線を使用した。ここで、異方性導電部材２０２に内包される金属端子２０３の導電材料として、金属細線を用いる場合には、金，銅，真ちゅう，リン青銅，ニッケル，ステンレス等で作られた円柱状金属細線またはこれらを主成分とする合金などが使用でき、金属細線以外の導電材料を用いる場合には、円柱状粒子径５〜１００μｍのカーボン粒子や金属粒子、金属メッキ処理を施した樹脂粒子等が使用できる。また、この異方性導電部材２０２の厚さは０．３ｍｍのものを使用した。加圧部品２０５による第一の基板１０１と第二の基板１０２及び異方性導電部材２０２を加圧する加圧力は１端子あたり０．６Ｎとした。さらに、加圧部品２０５は平板ばね形状であり、板厚は０．３ｍｍである。この加圧部品２０５の材質はＳＵＳ３０４ＣＰＳを使用する。
【００３５】
以上のようにして作成した第一実施例である回路基板装置の評価実験を、第一の基板１０１と第二の基板１０２の接続端子１０３、１０４の両端の相対的な位置決め精度を光学測定顕微鏡を用いて測定し、さらに、端子間の直流電気抵抗値を四探針法にて測定することにより接続端子１０３、１０４間の電気的導通状態の確認を実施した。結果、接続端子１０３、１０４の両端の相対的な位置決め精度は標準偏差０．２６５となり、接続端子間の電気的開放、短絡も発現しなかった。従って、チップコンデンサを位置決め用部材として用いる方法は、精確な接続端子間の位置決めが可能であるとともに、その実用性が確認された。
【００３６】
このように本実施例では、位置決め用チップ部品を搭載した基板と他の基板との接続に、ハンダなどの加熱処理を必要とする媒体を用いず、異方性導電部材を使用することで、その電気的導通のための特別な加熱等の必要がないことから、位置決め用チップ部品に高融点ハンダ等を用いる必要がなく、製造設備やリフロープロファイル等製造条件を変更する必要がない。
【００３７】
本実施例では、第一の基板１０１にＦＰＣ基板、第二の基板１０２にＲＰＣ基板を採用しているが、それぞれどちらの基板を用いても差し支えない。本実施例では、接続端子１０３、１０４のピッチ垂直方向（図中奥行き方向）の位置決めを第一の基板１０１と第二の基板１０２の端部（図中破断線反対側）を突き当てることにより行っているが、予め第二の基板１０２の上にピッチ垂直方向位置決め用チップコンデンサを表面実装することにより端部突き当てを行わなくても位置決めを実施することができる。また、位置決め用部品はチップコンデンサに限られるものではなく、チップ抵抗、チップインダクタ、もしくは、位置決め専用に製作した電気的には機能しないダミー部品でも同様の効果が得られ、位置決め用部品の数量も任意に設定しても差し支えない。本実施例では、接続端子１０３、１０４間に異方性導電部材２０２を挟み込んでいるが、これに限定されるものではなく、接続端子１０３、１０４を直に接触させて用いても問題ない。
【００３８】
［実施例２］
図３は、本発明の第２の実施例を示す図である。ここで図３（ａ）は本発明の第２の実施例の分解工程斜視図、図３（ｂ）は本発明の第２の実施例の組立後斜視図、図３（ｃ）は図３（ｂ）のＡ−Ａ断面模式図である。
【００３９】
第一の基板１０１は、ＰＩ（ポリイミド樹脂）を主原料とした可撓性樹脂フィルムである基材とＣｕ配線からなるフレキシブルプリント配線基板（ＦＰＣ基板）で、第一の基板１０１裏面（図中下側）には０．３ｍｍピッチ（配線幅０．１５ｍｍ、配線間隔０．１５ｍｍ）の接続端子１０３を１５本形成してある。第二の基板１０２は、ＦＲ４である基材とＣｕ配線からなるリジッドプリント配線基板（ＲＰＣ基板）で、第二の基板１０２表面（図中上側）には０．３ｍｍピッチ（配線幅０．１５ｍｍ、配線間隔０．１５ｍｍ）の接続端子１０４を１５本形成してある。さらに、第二の基板１０２の接続端子１０４と同一面に、チップコンデンサ２０１ａ、２０１ｂをその外形最短距離が第一の基板１０１のピッチ方向の基板外形と等しくなるよう、図示しないＬＳＩ（大規模集積回路）と同一工程でチップマウンタを用いて予め形成しておいた接続パッド上に精確に位置決めし、ハンダリフロープロセスにより表面実装した。このとき、チップコンデンサ２０１ａ、２０１ｂはハンダリフロー時のハンダ表面張力によるセルフアライメント効果により、位置精度±０．０５０ｍｍ以内で実装され、図示しないＬＳＩとは図示しない配線パターンにより連通している。第一の基板１０１の接続端子１０３上には、厚さ１０μｍのハンダ３０１を電気メッキ法にて形成してある。
【００４０】
第一の基板１０１と第二の基板１０２の位置決めは、接続端子１０３と接続端子１０４とを互いに対向させて配置し、第一の基板１０１を第二の基板１０２上に表面実装してあるチップコンデンサ２０１ａ、２０１ｂ間に嵌合させて実施した。この時、接続端子１０３、１０４のピッチ垂直方向（図中奥行き方向）の位置決めは第一の基板１０１と第二の基板１０２の端部（図中破断線反対側）を突き当てることにより行った。次に図示しない加熱加圧部品により第一の基板１０１と第二の基板１０２の接続端子１０３、１０４を上下方向に加熱加圧することによりハンダ３０１を溶融させ、その後冷却することにより電気的に接続して回路基板装置を製造した。
【００４１】
ここで、加熱加圧時のチップコンデンサ２０１ａ、２０１ｂの移動もしくは遊離を防止するために、接続端子１０３上のハンダ３０１は、先のＬＳＩやチップコンデンサ２０１ａ、２０１ｂを表面実装したハンダより低融点である必要がある。本実施例では接続端子１０３上のハンダ材には融点が９０℃の低融点ハンダを、ＬＳＩやチップコンデンサ２０１ａ、２０１ｂを表面実装するハンダ材には融点が１８３℃の共晶組成ハンダを使用した。
【００４２】
以上のようにして作成した第二実施例である回路基板装置の評価実験を、第一の基板１０１と第二の基板１０２の接続端子１０３、１０４の両端の相対的な位置決め精度を光学測定顕微鏡を用いて測定し、さらに、端子間の直流電気抵抗値を四探針法にて測定することにより接続端子１０３、１０４間の電気的導通状態の確認を実施した。結果、接続端子１０３、１０４の両端の相対的な位置決め精度は標準偏差０．２７１となり、接続端子間の電気的開放、短絡も発現しなかった。従って、チップコンデンサを位置決め用部材として用いる方法は、精確な接続端子間の位置決めが可能であるとともに、その実用性が確認された。
【００４３】
本実施例では、第一の基板１０１にＦＰＣ基板、第二の基板１０２にＲＰＣ基板を採用しているが、それぞれどちらの基板を用いても差し支えない。本実施例では、接続端子１０３、１０４のピッチ垂直方向（図中奥行き方向）の位置決めを第一の基板１０１と第二の基板１０２の端部（図中破断線反対側）を突き当てることにより行っているが、予め第二の基板１０２の上にピッチ垂直方向位置決め用チップコンデンサを表面実装することにより端部突き当てを行わなくても位置決めを実施することができる。また、位置決め用部品はチップコンデンサに限られるものではなく、チップ抵抗、チップインダクタ、もしくは、位置決め専用に製作した電気的には機能しないダミー部品でも同様の効果が得られ、位置決め用部品の数量も任意に設定しても差し支えない。本実施例では、接続端子間の電気的接続部材にハンダ材を用いているが、これに限定されるものではなくＡＣＦ（ＡｎｉｓｏｔｒｏｐｉｃＣｏｎｄｕｃｔｉｖｅＦｉｌｍ）またはＡＣＰ（ＡｎｉｓｏｔｒｏｐｉｃＣｏｎｄｕｃｔｉｖｅＰａｓｔｅ）またはＮＣＦ（ＮｏｎＣｏｎｄｕｃｔｉｖｅＦｉｌｍ）またはＮＣＰ（ＮｏｎＣｏｎｄｕｃｔｉｖｅＰａｓｔｅ）を用いても問題ない。
【００４４】
［実施例３］
図４は、本発明の第３の実施例を示す図である。ここで図４（ａ）は本発明の第３の実施例の分解工程斜視図、図４（ｂ）は本発明の第３の実施例の組立後斜視図、図４（ｃ）は図４（ｂ）のＡ−Ａ断面模式図である。
【００４５】
第一の基板１０１は、ＰＩ（ポリイミド樹脂）を主原料とした可撓性樹脂フィルムである基材とＣｕ配線からなるフレキシブルプリント配線基板（ＦＰＣ基板）で、第一の基板１０１裏面（図中下側）には０．３ｍｍピッチ（配線幅０．１５ｍｍ、配線間隔０．１５ｍｍ）の接続端子１０３を１５本形成し、その最外周部には切込み４０１ａ、４０１ｂを形成した。第二の基板１０２は、ＦＲ４である基材とＣｕ配線からなるリジッドプリント配線基板（ＲＰＣ基板）で、第二の基板１０２表面（図中上側）には０．３ｍｍピッチ（配線幅０．１５ｍｍ、配線間隔０．１５ｍｍ）の接続端子１０４を１５本形成してある。さらに、第二の基板１０２の接続端子１０４と同一面に、チップコンデンサ２０１ａ、２０１ｂをその外形最短距離が第一の基板１０１に形成してある切込み４０１ａ、４０１ｂ間距離と等しくなるよう、図示しないＬＳＩ（大規模集積回路）と同一工程でチップマウンタを用いて予め形成しておいた接続パッド上に精確に位置決めし、ハンダリフロープロセスにより表面実装した。このとき、チップコンデンサ２０１ａ、２０１ｂはハンダリフロー時のハンダ表面張力によるセルフアライメント効果により、位置精度±０．０５０ｍｍ以内で実装され、図示しないＬＳＩとは図示しない配線パターンにより連通している。第一の基板１０１の接続端子１０３上には、厚さ１０μｍのハンダ３０１を電気メッキ法にて形成してある。ここで、第一の基板１０１に形成してある切込み４０１ａ、４０１ｂと第二の基板１０２上のチップコンデンサ２０１ａ、２０１ｂの接続端子１０４と垂直方向（図中奥行き方向）は同一寸法とした。
【００４６】
第一の基板１０１と第二の基板１０２の位置決めは、接続端子１０３と接続端子１０４とを互いに対向させて配置し、第一の基板１０１を第二の基板１０２上に表面実装してあるチップコンデンサ２０１ａ、２０１ｂ間に嵌合させて実施した。次に図示しない加熱加圧部品により第一の基板１０１と第二の基板１０２の接続端子１０３、１０４を上下方向に加熱加圧することによりハンダ３０１を溶融させ、その後冷却することにより電気的に接続して回路基板装置を製造した。ここで、加熱加圧時のチップコンデンサ２０１ａ、２０１ｂの移動もしくは遊離を防止するために、接続端子１０３上のハンダ３０１は、先のＬＳＩやチップコンデンサ２０１ａ、２０１ｂを表面実装したハンダより低融点である必要がある。本実施例では接続端子１０３上のハンダ材には融点が９０℃の低融点ハンダを、ＬＳＩやチップコンデンサ２０１ａ、２０１ｂを表面実装するハンダ材には融点が１８３℃の共晶組成ハンダを使用した。
【００４７】
以上のようにして作成した第三実施例である回路基板装置の評価実験を、第一の基板１０１と第二の基板１０２の接続端子１０３、１０４の両端の相対的な位置決め精度を光学測定顕微鏡を用いて測定し、さらに、端子間の直流電気抵抗値を四探針法にて測定することにより接続端子１０３、１０４間の電気的導通状態の確認を実施した。結果、接続端子１０３、１０４の両端の相対的な位置決め精度は標準偏差０．２３６となり、接続端子間の電気的開放、短絡も発現しなかった。従って、チップコンデンサを位置決め用部材として用いる方法は、精確な接続端子間の位置決めが可能であるとともに、その実用性が確認された。
【００４８】
本実施例では、第一の基板１０１にＦＰＣ基板、第二の基板１０２にＲＰＣ基板を採用しているが、それぞれどちらの基板を用いても差し支えない。本実施例では、位置決め用部品にチップコンデンサを用いているが、これに限られるものではなく、チップ抵抗、チップインダクタ、もしくは、位置決め専用に製作した電気的には機能しないダミー部品でも同様の効果が得られ、位置決め用部品の数量も任意に設定しても差し支えない。
【００４９】
本実施例では、接続端子間の電気的接続部材にハンダ材を用いているが、これに限定されるものではなくＡＣＦ（ＡｎｉｓｏｔｒｏｐｉｃＣｏｎｄｕｃｔｉｖｅＦｉｌｍ）やＡＣＰ（ＡｎｉｓｏｔｒｏｐｉｃＣｏｎｄｕｃｔｉｖｅＰａｓｔｅ）やＮＣＦ（ＮｏｎＣｏｎｄｕｃｔｉｖｅＦｉｌｍ）やＮＣＰ（ＮｏｎＣｏｎｄｕｃｔｉｖｅＰａｓｔｅ）を用いても問題ない。
【００５０】
【発明の効果】
以上説明したように、本発明によれば、高密度に配置された電極からなる電極パターン（接続端子）を有する一対のプリント配線基板間において、各々の電極パターン（接続端子）同士を電気的に接続するプリント配線基板同士の位置決めを、基板上に実装されるＬＳＩ等の実装部品と同一工程上で搭載・リフローされセルフアライメント効果により精確に表面実装された位置決め用チップ部品を利用して行うことにより、精確に且つ簡単に行うことができ、異方性導電部材とプリント配線基板との位置決めも精確に且つ簡単に行うことができる回路基板装置およびその製造方法が得られる。また、電気的接続媒体として異方性導電部材を用いた場合、その電気的導通のための特別な加熱等の必要がないことから、位置決め用チップ部品に高融点ハンダ等を用いる必要がなく、製造設備やリフロープロファイル等製造条件を変更する必要がないという利点がある。
【００５１】
また、従来方法で必要だったピン嵌合用貫通孔やアライメントマークにより発生していた基板上のデッドスペースを最小限に抑えることが可能となり、省スペース化が実現できる。さらに、専用の固定・位置決め用治工具や、画像認識を行うための光学的検出装置、プリント配線基板間同士の相対的な位置関係を計算する画像解析装置、プリント配線基板を任意の位置に移動させる部品移動手段（一般的に光学的検出装置にはＣＣＤカメラシステムが、画像解析装置にはコンピュータおよび専用の画像解析ソフトウエアが、部品移動手段にはロボットが用いられることが多い）を必要としないため、低コスト化を実現することができる。
【図面の簡単な説明】
【図１】本発明によるプリント配線基板間位置決め構造および回路基板装置の一実施形態の説明図である。
【図２】本発明の第１の実施例を示す斜視図および断面図である。
【図３】本発明の第２の実施例を示す斜視図および断面図である。
【図４】本発明の第３の実施例を示す斜視図および断面図である。
【図５】従来例によるプリント配線基板間位置決め構造および回路基板装置の説明図である。
【図６】従来例によるプリント配線基板間位置決め構造および回路基板装置の説明図である。
【図７】従来例によるプリント配線基板間位置決め構造および回路基板装置の説明図である。
【図８】従来例によるプリント配線基板間位置決め構造および回路基板装置の説明図である。
【符号の説明】
１０１第一の基板
１０２第二の基板
１０３、１０４接続端子
１０５ａ、１０５ｂ位置決め用チップ部品
２０１ａ、２０１ｂチップコンデンサ
２０２異方性導電部材
２０３金属端子
２０４絶縁性エラスチック樹脂材料
２０５加圧部品
３０１ハンダ
４０１ａ、４０１ｂ切込み
５０１ａ、５０１ｂ、５０２ａ、５０２ｂ位置決め用貫通孔
５０３位置決め治具
５０４ａ、５０４ｂピン
６０１ａ、６０１ｂ光学的検出装置
７０１プリント配線基板
７０２配線パターン
７０３位置決め用パターン
７０４突起
７０５部品
７０６位置決め用穴
８０１プリント配線基板
８０２接続端子
８０３ａ、８０３ｂ嵌合パターン
８０４プリント配線基板
８０５接続端子
８０６ａ、８０６ｂ嵌合パターン[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a circuit board device and a method of manufacturing the same, and more particularly, to electrically connect each electrode pattern (connection terminal) between a pair of printed wiring boards having electrode patterns (connection terminals) composed of electrodes arranged at high density. The present invention relates to a method for precisely positioning printed wiring boards to be electrically connected to each other and a circuit board device provided with printed wiring boards connected by the positioning method.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a mobile phone device, a PDA (Personal Digital Assistant) terminal, or many other electronic devices include a plurality of printed wiring boards on which many electronic components are mounted in a limited space. In recent years, in particular, the sophistication and the multifunctionality have been advanced, and a connection between a plurality of printed wiring boards having a large number of connection terminals has been required, and the pitch of the electrode pattern has been narrowed. Along with this, the connection terminals of the printed wiring boards are also narrowed in pitch, and there is a demand for a method of easily and precisely aligning the connection terminals having the narrowed pitches.
[0003]
As a conventional method of positioning between printed wiring boards, FIG. 5 shows a method using pin fitting, and FIG. 6 shows a method using image recognition and image processing. FIG. 5 is a perspective view showing a method for positioning the printed circuit boards using the pin fitting. Here, FIG. 5A is an exploded perspective view of a method of positioning between printed wiring boards, FIG. 5B is an assembled perspective view of a method of positioning between printed wiring boards, and FIG. It is an AA cross section schematic diagram of FIG.5 (b).
[0004]
First, paired connection terminals 103 and 104 are formed on the printed wiring boards 101 and 102, and circular or elliptical positioning through holes 501a, 501b, 502a, and 502b are formed at predetermined positions by punching or drilling. . At this time, the positional relationship between the connection terminal 103 and the positioning through-holes 501a and 501b is the same as the positional relationship between the connection terminal 104 and the positioning through-holes 502a and 502b. Next, positioning pins 504a, 504b having the same pitch and the same diameter as positioning through-holes 501a, 501b and 502a, 502b formed in positioning jig 503 and positioning through-holes 501a, 501b, 502a, 502b are sequentially formed. By the fitting, the alignment of the connection terminals 103 and 104 on the printed wiring boards 101 and 102 is completed.
[0005]
FIG. 6 is a perspective view showing a method of positioning between printed wiring boards using image recognition and image processing. Here, FIG. 6A is an exploded perspective view of a method of positioning between printed wiring boards, FIG. 6B is a perspective view after assembly of a method of positioning between printed wiring boards, and FIG. FIG. 7 is a schematic cross-sectional view taken along the line AA of FIG.
[0006]
First, paired connection terminals 103 and 104 are formed on the printed wiring boards 101 and 102, and the connection terminals 103 and 104 are read as image information by the optical detection devices 601a and 601b, and the relative positional relationship is not shown in the image analysis (not shown). Detect using a device. Next, the relative positions of the connection terminals 103 and 104 are corrected by a component moving means (not shown), and the printed wiring boards 101 and 102 are sequentially overlapped, whereby the alignment of the connection terminals 103 and 104 is completed.
[0007]
Further, as shown in FIG. 7, a solder is sufficiently attached to a circular positioning pattern 703 on a printed wiring board 701 on which a wiring pattern 702 is formed to form a hemispherical projection 704, and a component 705 to be positioned is formed. A method has been proposed in which a printed wiring board 701 and a component 705 are aligned by fitting a positioning hole 706 provided in advance to a projection 704 (for example, see Patent Document 1).
[0008]
Furthermore, as shown in FIG. 8, fitting patterns 803 a and 803 b of the same material as the connection terminals are formed on the printed wiring board 801 on which the connection terminals 802 are formed, and the printed wiring board 804 is connected to the printed wiring board 801. Are formed with the mating patterns 803a and 803b using the same material as the connection terminals 805 formed on the printed wiring board 805, and the printed wiring boards are mated with the mating patterns 803a, 806a and 803b and 806b, respectively. A method has been proposed in which the connection terminals 802 and 805 are aligned with each other by superposing 801 and 804 (for example, see Patent Document 2).
[0009]
Furthermore, although it is not a precise positioning method of printed wiring boards for electrically connecting electrode patterns to each other, a method of mounting a plurality of hybrid integrated circuits on a heat sink with good positional accuracy has been proposed. First, a power transistor, a chip capacitor, and the like are mounted on a ceramic substrate, and clips are connected to form a hybrid integrated circuit. Two of the chip capacitors located at diagonal portions are positioning components. An adhesive is applied to the heat sink, and a plurality of hybrid integrated circuits are temporarily mounted. Thereafter, the position of the entire hybrid integrated circuit is corrected using a position correcting jig so that the positions of the positioning components are aligned, and then the adhesive is cured (for example, see Patent Document 3).
[0010]
[Patent Document 1]
JP-A-8-37397 ([0015] to [0017], FIGS. 1 and 2)
[Patent Document 2]
JP 2001-127424 A ([0026] to [0033], FIG. 1)
[Patent Document 3]
JP-A-2001-313496 ([0040] to [0047], FIGS. 1 to 3)
[0011]
[Problems to be solved by the invention]
As described above, in an electronic device such as a mobile phone device or a PDA terminal, it is necessary to mount a plurality of printed wiring boards on which many electronic components are mounted in a limited space. In particular, in a mobile phone device and a PDA terminal, it is very important to reduce the thickness of the connecting portion and to save space.
[0012]
However, when a method of positioning between printed wiring boards using pin fitting is used, it is necessary to provide a through hole for passing fitting pins on the printed wiring board, and this portion is a pair of printed wiring boards. This resulted in a dead space on the substrate, which hindered space saving. Further, a separate tool for pin fitting is required, which has been a factor of cost increase.
[0013]
In addition, when a method of positioning between printed wiring boards using image recognition and image processing is used, a dead space on the printed wiring board can be minimized, but an optical system for performing image recognition is required. A target detection device, an image analysis device for calculating the relative positional relationship between printed wiring boards, and a component moving means for moving the printed wiring board to an arbitrary position are required. Generally, a CCD camera system is used for the optical detection device, a computer and dedicated image analysis software are used for the image analysis device, and a robot is used for the component moving means. As a result, the cost of the product was increased.
[0014]
Also, in the case of Patent Document 1, similarly to the case of using a method of positioning between printed wiring boards using pin fitting, a solder hemisphere for fitting and a through hole for passing the solder hemisphere for fitting on the printed wiring board are used. It is necessary to provide a hole, and this portion becomes a dead space on the pair of printed wiring boards, which hinders space saving.
[0015]
Also, in the case of Patent Literature 2, it is necessary to provide a fitting pattern on the printed wiring board as in the case of using a method of positioning between printed wiring boards using pin fitting and in the case of Patent Literature 1. However, this portion becomes a dead space on the pair of printed wiring boards, which hinders space saving.
[0016]
Further, in the case of Patent Document 3, a process of temporarily mounting a plurality of hybrid integrated circuits and then aligning the positions of the respective positioning components using a position correction jig is required. In addition, there is a problem that the use of the position correction jig increases the cost.
[0017]
SUMMARY OF THE INVENTION An object of the present invention is to provide a printed wiring board which electrically connects respective electrode patterns (connection terminals) between a pair of printed wiring boards having electrode patterns (connection terminals) formed of electrodes arranged at high density. It is an object of the present invention to provide a method for accurately and accurately implementing the positioning of the present invention while realizing space saving and cost reduction, and a circuit board device provided with a printed wiring board connected by the positioning method.
[0018]
[Means for Solving the Problems]
According to the present invention, a first substrate on which connection terminals are formed, a second substrate on which connection terminals corresponding to the connection terminals of the first substrate are formed, and a positioning device surface-mounted on the second substrate A positioning structure having a chip component, wherein positioning between the connection terminals of the first substrate and the second substrate is performed by fitting the outer shape of the first substrate and the positioning chip component. And a circuit board device provided with the same. Positioning chip components are accurately positioned using the self-alignment effect of solder reflow, using either chip capacitors, chip resistors, chip inductors, or dummy components that are specially manufactured and do not function electrically. You.
[0019]
As the first and second substrates, one or more of a multilayer flexible printed circuit board, a multilayer rigid printed circuit board, a double-sided flexible printed circuit board, a double-sided rigid printed circuit board, a single-sided flexible printed circuit board, and a single-sided rigid printed circuit board Can be used. An anisotropic conductive member can be used as the electrical connection medium between the corresponding connection terminals of the first and second substrates, and solder, ACF, ACP, NCF, or NCP can be used. It is desirable that the melting point of the bonding medium of the positioning chip component is higher than the melting point of the electrical connection medium of the corresponding connection terminals of the first and second substrates.
[0020]
Further, according to the present invention, the step of mounting the positioning chip components on the second printed wiring board on which the connection terminals are formed, and the step of mounting the first printed wiring board on which the connection terminals are formed, are both performed. A step of fitting between the positioning chip components on the second printed wiring board so that the connection terminals face each other and electrically connecting the two connection terminals to each other, thereby obtaining a circuit board device manufacturing method. . The positioning chip component is mounted on the second printed wiring board by positioning the chip component on connection pads formed on the second printed wiring board, and is performed by a solder reflow process. The configuration is such that the outer shape of the first printed wiring board fits between the positioning chip components on the second printed wiring board.
[0021]
The printed wiring board positioning structure and the circuit board device according to the present invention include a first substrate on which connection terminals are formed, and a second substrate on which connection terminals corresponding to the connection terminals of the first substrate are formed. On the same surface as the connection terminals of the second substrate, a positioning chip component having a substantially rectangular parallelepiped shape is precisely positioned on connection pads formed in advance using a chip mounter, and is surface-mounted by a solder reflow process. At this time, the positioning chip component is accurately mounted by a self-alignment effect due to solder surface tension at the time of solder reflow. The positioning of the first substrate and the second substrate is performed by arranging the connection terminals so as to face each other, and fitting the first substrate between the positioning chip components surface-mounted on the second substrate. carry out.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of one embodiment of a method for manufacturing a circuit board device by positioning between printed wiring boards according to the present invention. Here, FIG. 1A is an exploded perspective view of a method for positioning between printed wiring boards according to the present invention, FIG. 1B is a perspective view after assembly of a method for positioning between printed wiring boards according to the present invention, FIG. 1C is a schematic cross-sectional view taken along the line AA of FIG.
[0023]
The present invention provides a first substrate 101 having connection terminals 103 formed on the back surface (lower side in the figure) of the substrate and a second substrate having connection terminals 104 corresponding to the connection terminals 103 formed on the surface of the substrate (the upper surface in the figure). Further, on the same surface as the connection terminals 104 of the second substrate 102, the substantially rectangular parallelepiped-shaped positioning chip components 105a and 105b In the same process as an LSI (not shown) (large-scale integrated circuit), a chip mounter is used to precisely position the connection pads, which have been formed in advance, so as to be equal to each other, and the surface is mounted by a solder reflow process. At this time, the positioning chip components 105a and 105b are accurately mounted by the self-alignment effect due to the solder surface tension at the time of solder reflow.
[0024]
Positioning of the first substrate 101 and the second substrate 102 is performed by positioning the connection terminals 103 and the connection terminals 104 so as to face each other, and mounting the first substrate 101 on the second substrate 102 by surface mounting. And is fitted between the chip components 105a and 105b. At this time, the positioning of the connection terminals 103 and 104 in the pitch vertical direction (the front-back direction in the drawing) is performed by abutting the ends of the first substrate 101 and the second substrate 102 (the side opposite to the broken line in the drawing). As a result, a circuit board device can be obtained in which the connection terminals 103 and 104 of the first substrate 101 and the second substrate 102 are accurately positioned, contacted, and electrically connected.
[0025]
Here, the positioning of the connection terminals 103 and 104 in the pitch vertical direction (front-rear direction in the figure) is performed by abutting the ends of the first substrate 101 and the second substrate 102 (the side opposite to the broken line in the figure). Alternatively, the chip component for pitch vertical direction positioning may be surface-mounted on the second substrate 102 in advance. In addition, the same effect can be obtained with a chip capacitor, a chip resistor, a chip inductor, or a dummy component which is manufactured exclusively for positioning and does not function electrically as a positioning component, and the number of positioning components can be set arbitrarily. No problem.
[0026]
The types of the first and second substrates 101 and 102 are not limited to a flexible printed circuit board (FPC board) or a rigid printed circuit board (RPC board). This is because the first and second substrates 101 and 102 can be realized by using either type. Further, as the first and second substrates, any of a multilayer flexible printed circuit board, a multilayer rigid printed circuit board, a double-sided flexible printed circuit board, a double-sided rigid printed circuit board, a single-sided flexible printed circuit board, and a single-sided rigid printed circuit board may be used. Can be.
[0027]
ADVANTAGE OF THE INVENTION According to this invention, between the pair of printed wiring boards which have the electrode pattern (connection terminal) which consists of an electrode arranged at high density, the printed wiring board which electrically connects each electrode pattern (connection terminal) Positioning is accurately and easily performed by using positioning chip components that are mounted and reflowed in the same process as the mounting components such as LSI mounted on the board and are precisely surface-mounted by the self-alignment effect. And a method for manufacturing the same.
[0028]
As a mounting / reflow technology for positioning chip components that are mounted and reflowed in the same process as mounting components such as LSI mounted on a substrate, pad dimensions can be set to +0.01 mm to +0.05 mm of the positioning chip component outer shape. By controlling the amount of solder paste printed and the reflow temperature profile (heating temperature / speed, heating holding time, cooling temperature / speed, etc.), the self-alignment effect can be maximized, and accurate mounting can be realized. Here, the pad dimensions may be applied only to the direction in which high-precision positioning is particularly required, and the direction in which high-precision positioning is not required does not have any problem other than the pad dimensions.
[0029]
Further, it is possible to minimize the dead space on the substrate caused by the pin-fitting through holes and the alignment marks, which is required in the conventional method, thereby realizing space saving. In addition, a dedicated fixing / positioning jig, an optical detection device for performing image recognition, an image analysis device for calculating the relative positional relationship between printed wiring boards, and moving a printed wiring board to an arbitrary position A component moving means (generally, a CCD camera system is generally used for an optical detection device, a computer and dedicated image analysis software are used for an image analyzing device, and a robot is often used for the component moving means). Therefore, cost reduction can be realized.
[0030]
Hereinafter, a circuit board structure and a method of positioning between boards according to the present invention will be described with reference to specific examples.
[0031]
[Example 1]
FIG. 2 shows a first embodiment of the present invention. 2A is a perspective view of an exploded process of the first embodiment of the present invention, FIG. 2B is a perspective view of the first embodiment of the present invention after assembly, and FIG. 2C is FIG. FIG. 2B is a schematic cross-sectional view taken along the line AA, and FIG. 2D is a schematic cross-sectional view taken along the line BB in FIG.
[0032]
The first substrate 101 is a flexible printed wiring board (FPC board) composed of a substrate, which is a flexible resin film mainly composed of PI (polyimide resin), and Cu wiring, and the back surface of the first substrate 101 (in the figure, On the lower side, 15 connection terminals 103 having a 0.3 mm pitch (wiring width 0.15 mm, wiring interval 0.15 mm) are formed. The second substrate 102 is a rigid printed wiring board (RPC substrate) composed of a FR4 base material and Cu wiring, and has a 0.3 mm pitch (wiring width 0.15 mm) on the surface (upper side in the figure) of the second substrate 102. And 15 connection terminals 104 with a wiring interval of 0.15 mm). Further, on the same surface as the connection terminals 104 of the second substrate 102, the chip capacitors 201a and 201b are mounted on an LSI (large-scale integrated circuit, not shown) such that the outermost shortest distance is equal to the outer shape of the substrate in the pitch direction of the first substrate 101. In the same process as that of the circuit), a chip mounter was used to precisely position a connection pad previously formed using a chip mounter, and was surface-mounted by a solder reflow process. At this time, the chip capacitors 201a and 201b are mounted within a positional accuracy of ± 0.050 mm due to a self-alignment effect due to solder surface tension at the time of solder reflow, and communicate with an unillustrated LSI by an unillustrated wiring pattern.
[0033]
The positioning of the first substrate 101 and the second substrate 102 is performed by a chip in which the connection terminals 103 and the connection terminals 104 are arranged to face each other, and the first substrate 101 is surface-mounted on the second substrate 102. The test was performed by fitting between the capacitors 201a and 201b. At this time, the positioning of the connection terminals 103 and 104 in the pitch vertical direction (the depth direction in the figure) was performed by abutting the ends of the first substrate 101 and the second substrate 102 (the side opposite to the broken line in the figure). . Further, between the first substrate 101 and the second substrate 102, the anisotropic conductive member 202 including the metal terminals 203 formed corresponding to the connection terminals 103 and 104 is attached to the first substrate 101. Is fitted and positioned between the chip capacitors 201a and 201b surface-mounted on the second substrate 102, sandwiched between the first substrate 101 and the second substrate 102, and And electrically connected to produce a circuit board device.
[0034]
The anisotropic conductive member 202 uses an insulating elastic resin material 204 made of silicone rubber having a rubber hardness of 50 degrees (JIS-K-6249), and the metal terminal 203 is made of an Au-plated SUS wire having a diameter of 12 μm. It was used. When a thin metal wire is used as the conductive material of the metal terminal 203 included in the anisotropic conductive member 202, a columnar thin metal wire made of gold, copper, brass, phosphor bronze, nickel, stainless steel, or the like. Alternatively, alloys containing these as main components can be used, and when conductive materials other than fine metal wires are used, carbon particles or metal particles having a columnar particle diameter of 5 to 100 μm, resin particles subjected to metal plating, and the like are used. it can. The thickness of the anisotropic conductive member 202 was 0.3 mm. The pressing force for pressing the first and second substrates 101 and 102 and the anisotropic conductive member 202 by the pressing component 205 was set to 0.6 N per terminal. Further, the pressing component 205 has a flat spring shape and a thickness of 0.3 mm. SUS 304 CPS is used as the material of the pressurizing component 205.
[0035]
The evaluation experiment of the circuit board device of the first embodiment created as described above was performed by using an optical measurement microscope to determine the relative positioning accuracy of both ends of the connection terminals 103 and 104 of the first board 101 and the second board 102. And the DC electrical resistance between the terminals was measured by a four-probe method to confirm the electrical conduction between the connection terminals 103 and 104. As a result, the relative positioning accuracy of both ends of the connection terminals 103 and 104 was a standard deviation of 0.265, and neither electrical opening nor short circuit between the connection terminals occurred. Therefore, the method of using the chip capacitor as the positioning member enables accurate positioning between the connection terminals, and its practicality has been confirmed.
[0036]
As described above, in this embodiment, the connection between the substrate on which the positioning chip component is mounted and another substrate is not performed by using a medium that requires heat treatment such as solder, and by using an anisotropic conductive member. Since there is no need for special heating or the like for the electrical continuity, there is no need to use a high melting point solder or the like for the positioning chip component, and there is no need to change the manufacturing equipment and the manufacturing conditions such as the reflow profile.
[0037]
In this embodiment, an FPC board is used as the first board 101 and an RPC board is used as the second board 102, but either board may be used. In this embodiment, the positioning of the connection terminals 103 and 104 in the pitch vertical direction (the depth direction in the figure) is performed by abutting the ends of the first substrate 101 and the second substrate 102 (the side opposite to the broken line in the figure). However, by performing surface mounting of the chip capacitor for pitch vertical direction positioning on the second substrate 102 in advance, positioning can be performed without performing end contact. In addition, the positioning components are not limited to chip capacitors, and the same effect can be obtained with chip resistors, chip inductors, or dummy components that are manufactured exclusively for positioning and do not function electrically. It can be set arbitrarily. In this embodiment, the anisotropic conductive member 202 is interposed between the connection terminals 103 and 104, but the present invention is not limited to this, and there is no problem even if the connection terminals 103 and 104 are brought into direct contact.
[0038]
[Example 2]
FIG. 3 is a diagram showing a second embodiment of the present invention. Here, FIG. 3A is a perspective view of an exploded process of the second embodiment of the present invention, FIG. 3B is a perspective view after assembling of the second embodiment of the present invention, and FIG. It is an AA cross section schematic diagram of (b).
[0039]
The first substrate 101 is a flexible printed wiring board (FPC board) composed of a substrate, which is a flexible resin film mainly composed of PI (polyimide resin), and Cu wiring, and the back surface of the first substrate 101 (in the figure, On the lower side, 15 connection terminals 103 having a 0.3 mm pitch (wiring width 0.15 mm, wiring interval 0.15 mm) are formed. The second substrate 102 is a rigid printed wiring board (RPC substrate) composed of a FR4 base material and Cu wiring, and has a 0.3 mm pitch (wiring width 0.15 mm) on the surface (upper side in the figure) of the second substrate 102. And 15 connection terminals 104 with a wiring interval of 0.15 mm). Further, on the same surface as the connection terminals 104 of the second substrate 102, chip capacitors 201a and 201b are mounted on an LSI (not shown) such that the shortest distance of the outer shape becomes equal to the outer shape of the substrate in the pitch direction of the first substrate 101. In the same process as that of the circuit), a chip mounter was used to precisely position a connection pad previously formed using a chip mounter, and was surface-mounted by a solder reflow process. At this time, the chip capacitors 201a and 201b are mounted within a positional accuracy of ± 0.050 mm due to a self-alignment effect due to solder surface tension at the time of solder reflow, and communicate with an unillustrated LSI by an unillustrated wiring pattern. On the connection terminals 103 of the first substrate 101, a solder 301 having a thickness of 10 μm is formed by electroplating.
[0040]
The positioning of the first substrate 101 and the second substrate 102 is performed by a chip in which the connection terminals 103 and the connection terminals 104 are arranged to face each other, and the first substrate 101 is surface-mounted on the second substrate 102. The test was performed by fitting between the capacitors 201a and 201b. At this time, the positioning of the connection terminals 103 and 104 in the pitch vertical direction (the depth direction in the figure) was performed by abutting the ends of the first substrate 101 and the second substrate 102 (the side opposite to the broken line in the figure). . Next, the connection terminals 103 and 104 of the first substrate 101 and the second substrate 102 are heated and pressed in the vertical direction by a heating and pressing part (not shown) to melt the solder 301, and then to cool and electrically connect the terminals. Thus, a circuit board device was manufactured.
[0041]
Here, in order to prevent movement or separation of the chip capacitors 201a and 201b during heating and pressurization, the solder 301 on the connection terminal 103 has a lower melting point than the solder in which the LSI or the chip capacitors 201a and 201b are surface-mounted. Need to be. In this embodiment, a low melting point solder having a melting point of 90 ° C. was used as the solder material on the connection terminal 103, and a eutectic composition solder having a melting point of 183 ° C. was used as the solder material for surface mounting the LSI and the chip capacitors 201a and 201b. .
[0042]
An evaluation experiment of the circuit board device according to the second embodiment prepared as described above was performed by using an optical measurement microscope to determine the relative positioning accuracy of both ends of the connection terminals 103 and 104 of the first board 101 and the second board 102. And the DC electrical resistance between the terminals was measured by a four-probe method to confirm the electrical conduction between the connection terminals 103 and 104. As a result, the relative positioning accuracy of both ends of the connection terminals 103 and 104 was a standard deviation of 0.271, and electrical opening and short circuit between the connection terminals did not occur. Therefore, the method of using the chip capacitor as the positioning member enables accurate positioning between the connection terminals, and its practicality has been confirmed.
[0043]
In this embodiment, an FPC board is used as the first board 101 and an RPC board is used as the second board 102, but either board may be used. In this embodiment, the positioning of the connection terminals 103 and 104 in the pitch vertical direction (the depth direction in the figure) is performed by abutting the ends of the first substrate 101 and the second substrate 102 (the side opposite to the broken line in the figure). However, by performing surface mounting of the chip capacitor for pitch vertical direction positioning on the second substrate 102 in advance, positioning can be performed without performing end contact. In addition, the positioning components are not limited to chip capacitors, and the same effect can be obtained with chip resistors, chip inductors, or dummy components that are manufactured exclusively for positioning and do not function electrically. It can be set arbitrarily. In this embodiment, a solder material is used as an electrical connection member between the connection terminals. However, the present invention is not limited to this. ACF (Anisotropic Conductive Film), ACP (Anisotropic Conductive Paste), or NCF (Non Conductive Film). Alternatively, there is no problem even if NCP (Non Conductive Paste) is used.
[0044]
[Example 3]
FIG. 4 is a diagram showing a third embodiment of the present invention. Here, FIG. 4A is a perspective view of an exploded process of the third embodiment of the present invention, FIG. 4B is a perspective view of the third embodiment of the present invention after assembly, and FIG. It is an AA cross section schematic diagram of (b).
[0045]
The first substrate 101 is a flexible printed wiring board (FPC board) composed of a base material, which is a flexible resin film mainly composed of PI (polyimide resin), and Cu wiring, and has a back surface of the first substrate 101 (in FIG. Fifteen connection terminals 103 having a 0.3 mm pitch (wiring width 0.15 mm, wiring interval 0.15 mm) were formed on the lower side, and cuts 401a and 401b were formed in the outermost peripheral portion. The second substrate 102 is a rigid printed wiring board (RPC substrate) composed of a FR4 base material and Cu wiring, and has a 0.3 mm pitch (wiring width 0.15 mm) on the surface (upper side in the figure) of the second substrate 102. And 15 connection terminals 104 with a wiring interval of 0.15 mm). Further, chip capacitors 201a and 201b are not shown on the same surface as the connection terminals 104 of the second substrate 102 such that the shortest external distance of the chip capacitors 201a and 201b is equal to the distance between the cuts 401a and 401b formed on the first substrate 101. In the same process as the LSI (Large Scale Integrated Circuit), a chip mounter was used to precisely position on the previously formed connection pads using a chip mounter, and the surface was mounted by a solder reflow process. At this time, the chip capacitors 201a and 201b are mounted within a positional accuracy of ± 0.050 mm due to a self-alignment effect due to solder surface tension at the time of solder reflow, and communicate with an unillustrated LSI by an unillustrated wiring pattern. On the connection terminals 103 of the first substrate 101, a solder 301 having a thickness of 10 μm is formed by electroplating. Here, the notches 401a and 401b formed on the first substrate 101 and the connection terminals 104 of the chip capacitors 201a and 201b on the second substrate 102 have the same dimension as the vertical direction (the depth direction in the drawing).
[0046]
The positioning of the first substrate 101 and the second substrate 102 is performed by a chip in which the connection terminals 103 and the connection terminals 104 are arranged to face each other, and the first substrate 101 is surface-mounted on the second substrate 102. The test was performed by fitting between the capacitors 201a and 201b. Next, the connection terminals 103 and 104 of the first substrate 101 and the second substrate 102 are vertically heated and pressed by a heating / pressing part (not shown) to melt the solder 301 and thereafter cool to electrically connect the terminals. Thus, a circuit board device was manufactured. Here, in order to prevent movement or separation of the chip capacitors 201a and 201b during heating and pressurization, the solder 301 on the connection terminal 103 has a lower melting point than the solder in which the LSI or the chip capacitors 201a and 201b are surface-mounted. Need to be. In this embodiment, a low melting point solder having a melting point of 90 ° C. was used as the solder material on the connection terminal 103, and a eutectic composition solder having a melting point of 183 ° C. was used as the solder material for surface mounting the LSI and the chip capacitors 201a and 201b. .
[0047]
An evaluation experiment of the circuit board device according to the third embodiment prepared as described above was performed by using an optical measurement microscope to determine the relative positioning accuracy of both ends of the connection terminals 103 and 104 of the first board 101 and the second board 102. And the DC electrical resistance between the terminals was measured by a four-probe method to confirm the electrical conduction between the connection terminals 103 and 104. As a result, the relative positioning accuracy of both ends of the connection terminals 103 and 104 was a standard deviation of 0.236, and electrical opening and short circuit between the connection terminals did not occur. Therefore, the method of using the chip capacitor as the positioning member enables accurate positioning between the connection terminals, and its practicality has been confirmed.
[0048]
In this embodiment, an FPC board is used as the first board 101 and an RPC board is used as the second board 102, but either board may be used. In this embodiment, the chip capacitor is used as the positioning component. However, the present invention is not limited to this, and a chip resistor, a chip inductor, or a dummy component that is manufactured exclusively for positioning and that does not function electrically has the same effect. Can be obtained, and the number of positioning components can be arbitrarily set.
[0049]
In this embodiment, a solder material is used as an electrical connection member between the connection terminals. However, the present invention is not limited to this, and the present invention is not limited thereto. There is no problem even if NCP (Non Conductive Paste) is used.
[0050]
【The invention's effect】
As described above, according to the present invention, each electrode pattern (connection terminal) is electrically connected between a pair of printed wiring boards having an electrode pattern (connection terminal) composed of electrodes arranged at high density. The positioning of the printed wiring boards to be connected must be performed using the positioning chip components that are mounted and reflowed in the same process as the mounting components such as LSI mounted on the substrate, and are precisely surface-mounted by the self-alignment effect. As a result, a circuit board device and a method of manufacturing the circuit board device that can be performed accurately and easily, and in which the positioning between the anisotropic conductive member and the printed wiring board can be performed accurately and easily, can be obtained. In addition, when an anisotropic conductive member is used as an electrical connection medium, since there is no need for special heating or the like for electrical conduction, there is no need to use a high melting point solder or the like for the positioning chip component, There is an advantage that there is no need to change manufacturing conditions such as manufacturing equipment and reflow profiles.
[0051]
Further, it is possible to minimize the dead space on the substrate caused by the pin-fitting through holes and the alignment marks, which is required in the conventional method, thereby realizing space saving. In addition, a dedicated fixing / positioning jig, an optical detection device for performing image recognition, an image analysis device for calculating the relative positional relationship between printed wiring boards, and moving a printed wiring board to an arbitrary position A component moving means (generally, a CCD camera system is generally used for an optical detection device, a computer and dedicated image analysis software are used for an image analyzing device, and a robot is often used for the component moving means). Therefore, cost reduction can be realized.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an embodiment of a printed wiring board positioning structure and a circuit board device according to the present invention.
FIG. 2 is a perspective view and a sectional view showing a first embodiment of the present invention.
FIG. 3 is a perspective view and a sectional view showing a second embodiment of the present invention.
FIG. 4 is a perspective view and a sectional view showing a third embodiment of the present invention.
FIG. 5 is an explanatory diagram of a printed wiring board positioning structure and a circuit board device according to a conventional example.
FIG. 6 is an explanatory diagram of a printed wiring board positioning structure and a circuit board device according to a conventional example.
FIG. 7 is an explanatory diagram of a printed wiring board positioning structure and a circuit board device according to a conventional example.
FIG. 8 is an explanatory diagram of a printed wiring board positioning structure and a circuit board device according to a conventional example.
[Explanation of symbols]
101 First substrate
102 Second substrate
103, 104 connection terminal
105a, 105b Positioning chip components
201a, 201b Chip capacitors
202 Anisotropic conductive member
203 metal terminal
204 Insulating elastic resin material
205 pressurized parts
301 Solder
401a, 401b cut
501a, 501b, 502a, 502b Positioning through holes
503 Positioning jig
504a, 504b pins
601a, 601b Optical detection device
701 Printed Wiring Board
702 Wiring pattern
703 Positioning pattern
704 protrusion
705 parts
706 Positioning hole
801 Printed wiring board
802 connection terminal
803a, 803b Fitting pattern
804 printed wiring board
805 connection terminal
806a, 806b Fitting pattern

Claims

A first substrate on which connection terminals are formed, a second substrate on which connection terminals corresponding to the connection terminals of the first substrate are formed, and a positioning chip component surface-mounted on the second substrate. A circuit board device provided with a positioning structure, wherein positioning between the connection terminals of the first substrate and the second substrate is performed by fitting an outer shape of the first substrate and the positioning chip component.

2. The circuit board device according to claim 1, wherein the positioning chip component is any one of a chip capacitor, a chip resistor, a chip inductor, and a dummy component which is manufactured exclusively for positioning and does not function electrically.

3. The circuit board device according to claim 1, wherein the positioning chip component is accurately positioned by utilizing a self-alignment effect by solder reflow.

The first and second substrates use at least one of a multilayer flexible printed circuit board, a multilayer rigid printed circuit board, a double-sided flexible printed circuit board, a double-sided rigid printed circuit board, a single-sided flexible printed circuit board, and a single-sided rigid printed circuit board. The circuit board device according to any one of claims 1 to 3, wherein:

The circuit board device according to claim 1, wherein an anisotropic conductive member is used as an electrical connection medium between the corresponding connection terminals of the first and second substrates.

Solder or ACF (Anisotropic Conductive Film) or ACP (Anisotropic Conductive Paste) or NCF (Non Conductive Film) or NCF (Non Conductive Film) is used as an electrical connection medium between the corresponding connection terminals of the first and second substrates. The circuit board device according to any one of claims 1 to 4, wherein

7. The circuit board device according to claim 6, wherein the melting point of the bonding medium of the positioning chip component is higher than the melting point of the electrical connection medium between the corresponding connection terminals of the first and second substrates. .

Mounting the positioning chip components on the second printed wiring board on which the connection terminals are formed, and mounting the first printed wiring board on which the connection terminals are formed so that both connection terminals face each other. A step of fitting between the positioning chip components on the second printed wiring board and electrically connecting both connection terminals to each other.

9. The method according to claim 8, wherein an outer shape of the first printed wiring board is fitted between positioning chip components on the second printed wiring board.

The positioning chip component is mounted on the second printed wiring board by positioning the positioning chip component on connection pads formed on the second printed wiring board, and is mounted by a solder reflow process. The method for manufacturing a circuit board device according to claim 8.