JP4151101B2 - Electrode connecting adhesive, fine electrode connecting structure using the same, and electrode connecting method - Google Patents
Electrode connecting adhesive, fine electrode connecting structure using the same, and electrode connecting method Download PDFInfo
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- JP4151101B2 JP4151101B2 JP03948298A JP3948298A JP4151101B2 JP 4151101 B2 JP4151101 B2 JP 4151101B2 JP 03948298 A JP03948298 A JP 03948298A JP 3948298 A JP3948298 A JP 3948298A JP 4151101 B2 JP4151101 B2 JP 4151101B2
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/321—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives
- H05K3/323—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives by applying an anisotropic conductive adhesive layer over an array of pads
Description
【０００１】
【発明の属する技術分野】
本発明は、第１の電子部品上の電極と第２の電子部品の電極との間に載置し、相対峙した電極間を電気的に接続、接着する目的に使用される電極接続用接着剤及びこれを用いた微細電極の接続構造、並びに、電極の接続方法に関する。
【０００２】
【従来の技術】
半導体パッケージや回路基板等の電子部品の小形薄形化に伴い、これらに用いる電極は高密度・高精細化している。これら微細電極の接続は、従来の半田やゴムコネクタ等では対応が困難であることから、最近では異方導電性の接着剤からなる接続部材が多用されるようになってきた。この方法は、相対峙する電極間に導電性材料を所定量含有した接着剤よりなる接続部材層を設け、加圧もしくは加熱加圧手段を講じることによって、上下電極間の電気的接続と同時に隣接電極間には絶縁性を付与し、相対峙する電極を接着固定するものである。接着剤の硬化手段としては、熱可塑性接着剤による室温冷却による固化や熱硬化性樹脂による加熱硬化、光硬化性樹脂による紫外線や可視光硬化等がある。また、化学反応による接着剤の硬化手段の１つに、ラジカル重合反応を利用したものが知られている。これは、熱や光エネルギーによりラジカルを発生させ、接着剤を重合硬化するものである。
厚み方向にのみ導電性を有する異方導電性フィルム状接着剤に関する先行技術としては、例えば特開昭５１−２１１９２号公報に開示されているように、導電粒子を非導電性ベースにより互いに接触しない状態に保持した混合体を、導電粒子の大きさにほぼ等しい厚さのシート状に成形し、導電粒子を介してシート状の厚み方向にのみ導電性を有する構造としたものがある。また、紫外線照射によるラジカル重合反応を利用した異方導電性接着剤としては、特開昭６０−２６２４３６号公報等に開示されている方法が知られている。
これらのラジカル重合反応を利用した異方導電性接着剤は、アクリロイル基を持つモノマやオリゴマを数種組み合わせ、紫外線等でラジカルを発生する光重合開始剤を少量添加した接着剤組成である。しかし、これまでラジカル重合反応を利用した異方導電性接着剤では、耐熱性と接着力を両立した接続信頼性の高い接続が得られないという問題があった。具体的には、これまで接着剤硬化物の耐熱性を向上して高温条件下での充分な接続信頼性を得るためには、多官能のアクリルモノマ量を多くし、接着剤中の反応性基であるアクリル基の濃度を高くする必要があった。しかし、この方法では高弾性で伸びの小さな硬化物になるため接着力が低下し、接続界面の剥離が進行しやすく、充分な接続信頼性が得られなかった。また、接着剤にシランカップリング剤を添加することで接着力を向上することができるが、シランカップリング剤の反応を進行させ接着力を向上するためには、接続温度を高くするか接続時間を長くしなければならず、低温短時間で硬化可能であるという光硬化性接着剤の特長を充分に生かすことができなかった。
【０００３】
【発明が解決しようとする課題】
本発明は、かかる状況に鑑みてなされたもので、接着力並びに接続信頼性に優れた電極接続用接着剤の新規な構成を提供せんとするものである。
【０００４】
【課題を解決するための手段】
すなわち本発明は、第１の電子部品上の電極と第２の電子部品の電極との間に載置し、相対峙した電極間を電気的に接続、接着する目的に使用される電極接続用接着剤において、光酸発生剤、シランカップリング剤、ラジカル重合性アクリル化合物、光反応開始剤を必須成分としてなり、前記ラジカル重合性アクリル化合物が、ウレタンアクリレートオリゴマと、アクリロイル基もしくはメタクリロイル基を３つ以上持つラジカル重合性アクリル化合物と、を含有する、電極接続用接着剤および前記電極接続用接着剤を用いた微細電極の接続構造に関する。また、本発明は、第１の電子部品上の電極と第２の電子部品の電極との間に電極接続用接着剤を載置し、相対峙した電極間を電気的に接続、接着する電極の接続方法であって、前記電極接続用接着剤が、光酸発生剤、シランカップリング剤、ラジカル重合性アクリル化合物、光反応開始剤を必須成分としてなるものであり、前記ラジカル重合性アクリル化合物が、ウレタンアクリレートオリゴマと、アクリロイル基もしくはメタクリロイル基を３つ以上持つラジカル重合性アクリル化合物と、を含有するものであり、電極間の接続時に、加熱加圧状態で前記電極接続用接着剤への紫外線照射を行う、電極の接続方法に関する。
【０００５】
【発明の実施の形態】
本発明は、電極接続用接着剤の必須成分として光酸発生剤、シランカップリング剤、ラジカル重合性アクリル化合物、光反応開始剤を用いることより、低温の接続条件でも接着力が高く接続信頼性の優れた電極接続用接着剤が得られるようになる。
光酸発生剤は光を吸収し酸を発生する物質で、生成した酸はシランカップリング剤のアルコキシシラン基の加水分解縮合反応の反応触媒として働き、光硬化性の電極接続用接着剤と被着体である基板との接着力を高めることができる。よって、従来の加熱のみでシランカップリング剤のアルコキシシラン基の加水分解縮合反応を進める場合よりも低温で速やかに反応が進ので、低温の接続条件で高い接着力が得られ、低温接続時の接続信頼性を向上できる。
光酸発生剤としては、種々のスルホニウム塩やヨードニウム塩が使用できるが、触媒活性が高いスルホニウム塩の方がより大きな反応促進硬化が得られるので好ましい。
シランカップリング剤としては、種々のアルコキシシランが使用できるが、あアクリロイル基を含有したものは、接着剤成分のラジカル重合性アクリル化合物と重合反応し、接着剤硬化物の一部となるのでより高い接着力が得られるので好ましい。
【０００６】
ラジカル重合性アクリル化合物としては、アクリロイル基を持つ種々のメタクリレートやアクリレート化合物のモノマあるいはオリゴマが用いられる。なかでも接着剤の硬化物の弾性率や耐熱性からアクリロイル基を２つ持つものを添加することが好ましい。
具体的にはアクリルモノマとしては、例えばポリエチレングリコールやポリプロピレングリコールの骨格の両端にアクリルあるいはメタクリル基があるものやビスフェノール骨格の両端にアクリルあるいはメタクリル基があるもの等を用いることができる。また、トリメチロールプロパントリメタクリレートやテトラメチロールメタンテトラアクリレート等のアクリロイル基を３つ以上持つものも適量添加することで耐熱性を向上することができる。アクリルオリゴマとしては、ポリエステルアクリレートやエポキシアクリレート、ウレタンアクリレート等のオリゴマを用いることができる。
光反応開始剤としては、アセトフェノン、ベンゾイン、ベンゾフェノン等の誘導体が紫外線による反応開始剤として使用でき、ジカルボニル化合物、チオキサントン、アシルホスフィンオキサイド等の誘導体は、可視光による反応開始剤として使用できる。また、これらにアミン化合物等の光反応促進剤を併用することはより、硬化反応を速やかに進行させるので好ましい。
【０００７】
また、接着剤成分の一部として、分子量１０，０００以上のフェノキシ樹脂、ポリエステル、ポリビニルブチラール、フェノール樹脂等の水酸基含有樹脂を添加すると、高分子化合物による硬化物の靭性の増加と水酸基による接着性が増し、信頼性が向上する。なかでもフェノキシ樹脂の水酸基にイソシアネート基を有するアクリルモノマを反応させ、側鎖にアクリロイル基を導入したアクリル変成フェノキシ樹脂を用いると、接続時に接着剤中のアクリル樹脂と反応するので、より耐熱性を向上することができる。アクリル変成フェノキシ樹脂中のビスフェノール構造に対するアクリロイル基の割合は、０．１から１の範囲で顕著な硬化物の耐熱性の向上が得られ、硬化物のガラス転移温度は、アクリロイル基の割合が大きくなるにつれ高くなる。よって、所望の耐熱性はアクリル変成フェノキシ樹脂中のビスフェノール構造に対するアクリロイル基の割合を調節することで得ることができる。しかし、アクリロイル基の割合が多くなるにつれ硬化物の靭性が損なわれる傾向があり、ビスフェノール構造に対するアクリロイル基の割合がおおむね０．１から０．５の範囲で、さらに最適な耐熱性と靭性の両立が得られる。
【０００８】
ここで、ビスフェノール構造に対するアクリロイル基の割合とは、分子中に含まれるビスフェノール構造の数と分子中に含まれるアクリロイル基の数の比を表している。すなわち、分子中のビスフェノール構造の数と分子中のアクリロイル基の数が同数のとき、ビスフェノール構造に対するアクリロイル基の割合は１であり、分子中のビスフェノール構造の数に対して分子中のアクリロイル基の数が１／１０のとき、ビスフェノール構造に対するアクリロイル基の割合は０．１である。また、固形の高分子化合物を適量添加することで、取り扱い性やポットライフに優れたフィルム状の電極接続用接着剤とすることができる。このフィルム状の電極接続用接着剤の厚みは特に限定するものではないが、接続する電極部分の凹凸に接着剤が充填することで接着力や耐湿性が向上することから、ＦＰＣ等の電極部の凹凸以上の厚みが適当である。また、薄くなると取り扱いが容易でなく、しわの発生等により製造が困難になってくることから、０．００５ｍｍ〜１ｍｍが適当である。
この接続工程で接着した硬化物のガラス転移温度は、前記の通りアクリル変成フェノキシ樹脂のビスフェノール構造に対するアクリロイル基の割合や、アクリルモノマやアクリルオリゴの構造や配合比で変化するが、ガラス転移温度が１００℃以上であるとき、８５℃８５％ＲＨの高温高湿試験や−４０℃〜１００℃の熱衝撃試験等の加速試験で接続部の剥離が無く、低抵抗な特に良好な接続信頼性が得られる。
また、この電極接続用接着剤に導電粒子を添加することで、さらに接続抵抗が小さく、高温高湿試験や熱サイクル試験等における抵抗上昇が抑えられた高信頼性の接続が得られる。この導電粒子は、Ｎｉ等の金属粒子や樹脂粒子の表面に、ＮｉやＡｕのめっき層を設けた金属めっき樹脂粒子を単独または複合して使用することができる。これらの導電粒子の材質は、接続する電極の堅さや変形性等の特性により最適なものを選択して用いる。また、粒径は、接続する回路の細かさにより選択されるが、各粒子の粒径はできるだけ均一である必要がある。
また、本発明の電極接続用接着剤は、上記した電極の接続材料だけでなく、多層回路部材の層間接続材等への応用が可能である。
【０００９】
【実施例】
以下、本発明の実施例に基づいて詳細を説明するが、本発明はこれに限定されるものではない。本実施例と比較例に使用した材料と評価方法を以下に示す。
光酸発生剤は芳香族スルホニウム塩（三新化学工業株式会社製、商品名サンエイド）を使用した。シランカップリング剤はγ−メタクリロキシプロピルトリメトキシシラン（東レ・ダウコーニング・シリコーン株式会社製、商品名ＳＺ６０３０）を使用した。ラジカル重合性アクリル化合物として、ウレタンアクリレートオリゴマ（新中村化学工業株式会社製、商品名ＵＡ−１２２Ｐ）を使用し、多官能のアクリルモノマであるテトラメチロールメタントリアクリレート（新中村化学工業株式会社製、商品名Ａ−ＴＭＭ−３Ｌ）を用いた。光反応開始剤としてはベンゾフェノン（試薬）を４％、光反応促進剤として４，４−ビスジエチルアミノベンゾフェノン（保土ヶ谷化学工業株式会社製、商品名ＥＡＢ）を１％添加した。水酸基含有樹脂としては、ポリビニルブチラール樹脂（電気化学工業株式会社製、商品名ＰＶＢ３０００Ｋ）とフェノキシ樹脂（ユニオンカーバイド株式会社製、商品名ＰＫＨＣ）を用いた。アクリル変成フェノキシ樹脂は、フェノキシ樹脂（ユニオンカーバイド株式会社製、商品名ＰＫＨＣ）と２−メタクリロイルオキシエチルイソシアネート（昭和電工株式会社製、商品名カレンズＭＯＩ）を反応させて得たものを用いた。
導電粒子は、平均粒径５μｍのポリスチレン球状粒子の表面に０．１μｍのＮｉ層とＡｕ層を設けたものを使用した。
液状の電極接続用接着剤はシリンジ状ディスペンサを用い、電極上に塗布して接続した。フィルム状の電極接続用接着剤は、メチルエチルケトンや酢酸エチルの溶剤で希釈した接着剤をアプリケーターでテフロンフィルム上に塗布したのち乾燥し、約２０μｍの厚さのフィルム状に成形した。接続時にはフィルム状の電極接続用接着剤をテフロンフィルムから電極面に転写し、テフロンフィルムを除去して用いた。
【００１０】
接続信頼性の評価は、ポリイミドフィルム上にライン幅５０μｍピッチ１００μｍ厚さ１８μｍの平行配列した銅電極を１００本有するＦＰＣと、表面抵抗２０Ω／□のＩＴＯ電極を有するガラス基板とを電極接続用接着剤により接続した試料を用いて行った。接続方法は、圧力２０ｋｇ／ｃｍ2で１３０℃２０秒間のまたは１５０℃３０秒間の加圧加熱状態で、接着剤に約２Ｊ／ｃｍ2の紫外線を照射し接続した。紫外線は高圧水銀ランプを光源とし、光ファイバにより接続部の接着剤に紫外線を導入する方法で照射した。
フィルム状に成形した硬化済みの接着剤について動的粘弾性測定を行い、ガラス転移温度を測定し、耐熱性の指標とした。硬化済み接着剤の作製条件は、１３０℃で紫外線を２Ｊ照射した硬化物を使用した。
接続抵抗は、１ｍＡの測定電流で各ラインごとに測定し、平均値を接続抵抗とした。信頼性評価は、−４０℃と１００℃の各試験槽に交互に試料を入れる熱サイクル試験１０００サイクルにて行った。
接着力の評価は、ＦＰＣのＩＴＯガラスへの接着性を９０度剥離試験にて測定した。
【００１１】
実施例１
ウレタンアクリレートオリゴマ６０％（重量、以下同じ）、テトラメチロールメタントリアクリレート２２％、シランカップリング剤１０％、光酸発生剤３％、光反応開始剤４％、光反応促進剤１％を均一混合し、回路接続用接着剤を作製した。
【００１２】
実施例２
ポリビニルブチラール樹脂４０％、ウレタンアクリレートオリゴマ３０％、テトラメチロールメタントリアクリレート１２％、シランカップリング剤１０％、光酸発生剤３％、光反応開始剤４％、光反応促進剤１％を均一混合し、フィルム状回路接続用接着剤を作製した。
【００１３】
実施例３
フェノキシ樹脂４０％、ウレタンアクリレートオリゴマ３０％、テトラメチロールメタントリアクリレート１２％、シランカップリング剤１０％、光酸発生剤３％、光反応促進剤１％を均一混合し、フィルム状回路接続用接着剤を作製した。
【００１４】
実施例４
ビスフェノール構造に対するアクリロイル基の割合が０．１であるアクリル変成フェノキシ樹脂４０％、ウレタンアクリレートオリゴマ３０％、テトラメチロールメタントリアクリレート１２％、シランカップリング剤１０％、光酸発生剤３％、光反応開始剤４％、光反応促進剤１％を均一混合し、フィルム状回路接続用接着剤を作製した。
【００１５】
実施例５
ビスフェノール構造に対するアクリロイル基の割合が０．３であるアクリル変成フェノキシ樹脂４０％、ウレタンアクリレートオリゴマ３０％、テトラメチロールメタントリアクリレート１２％、シランカップリング剤１０％、光酸発生剤３％、光反応開始剤４％、光反応促進剤１％を均一混合し、フィルム状回路接続用接着剤を作製した。
【００１６】
実施例６〜実施例１０
実施例１から５に導電粒子を５体積％添加したものをそれぞれ実施例６から実施例１０とした。
【００１７】
比較例１〜比較例１０
実施例１から１０の光酸発生剤を添加していないものをそれぞれ比較例１から１０とした。
各実施例と比較例のガラス転移温度、１３０℃２０秒接続での接着力、１５０℃３０秒接続での接着力、初期接続抵抗、信頼性試験後の接続抵抗を表１に示した。本発明にかかる電極接続用接着剤はいづれも比較的低い温度の接続条件でも接着力にすぐれ、かつ接続信頼性に優れている。
【００１８】
【表１】
【発明の効果】
請求項１記載の電極接続用接着剤は、低温の接続条件で高い接着力が得られ、接続信頼性の高い接続を得るのに好適である。
請求項２記載の電極接続用接着剤は、請求項１記載の効果を奏し、さらに低温の接続条件で接着性が優れる。
請求項３記載の電極接続用接着剤は、請求項１乃至２記載の効果を奏し、さらに接着力と接続信頼性が優れる。
請求項４記載の電極接続用接着剤は、請求項１乃至３記載の効果を奏し、接着力と接続信頼性に優れたフィルム状の電極接続用接着剤を得るのに好適である。
請求項５記載の電極接続用接着剤は、請求項１乃至４記載の効果を奏し、さらに接着力と接続信頼性に優れたフィルム状の電極接続用接着剤が得られる。
請求項６記載の電極接続用接着剤は、請求項１乃至５記載の効果を奏し、さらに耐熱性が高い電極接続用接着剤が得られる。
請求項７記載の電極接続用接着剤は、請求項１乃至６記載の効果を奏し、耐熱信頼性が高い電極接続用接着剤が得られる。
請求項８記載の電極接続用接着剤は、請求項１乃至７記載の効果を奏し、信頼性試験後の接続抵抗の上昇量が少ない電極接続用接着剤が得られる。
請求項９記載の電極接続用接着剤は、請求項１乃至８記載の効果を奏し、接着力と接続信頼性が高い微細電極の接続構造を提供することができる。
【図面の簡単な説明】
【図１】本発明にかかる導電粒子を含有した電極接続用接着剤を用いた電極接続構造の断面図。
【符号の説明】
１ 電極接続用接着剤 ２ 接着剤
３ 導電粒子 ４ 第１の電極
５ 第２の電極[0001]
BACKGROUND OF THE INVENTION
The present invention provides an electrode connection adhesive that is placed between an electrode on a first electronic component and an electrode of a second electronic component, and is used for the purpose of electrically connecting and adhering opposed electrodes. The present invention relates to an agent, a microelectrode connection structure using the same , and an electrode connection method .
[0002]
[Prior art]
As electronic parts such as semiconductor packages and circuit boards are made smaller and thinner, electrodes used for these components have become denser and more precise. Since connection of these fine electrodes is difficult with conventional solders, rubber connectors and the like, connection members made of an anisotropic conductive adhesive have recently been used frequently. In this method, a connecting member layer made of an adhesive containing a predetermined amount of a conductive material is provided between electrodes facing each other, and an electric connection between upper and lower electrodes is provided simultaneously by applying pressure or heating and pressing means. Insulation is provided between the electrodes, and the electrodes facing each other are bonded and fixed. Examples of the curing means for the adhesive include solidification by cooling at room temperature with a thermoplastic adhesive, heat curing with a thermosetting resin, and ultraviolet and visible light curing with a photocurable resin. Moreover, what utilized the radical polymerization reaction is known as one of the hardening means of the adhesive by a chemical reaction. In this method, radicals are generated by heat or light energy, and the adhesive is polymerized and cured.
As a prior art relating to an anisotropic conductive film adhesive having conductivity only in the thickness direction, for example, as disclosed in Japanese Patent Application Laid-Open No. 51-21192, conductive particles are not brought into contact with each other by a non-conductive base. There is a structure in which the mixture maintained in a state is formed into a sheet shape having a thickness substantially equal to the size of the conductive particles, and has a structure having conductivity only in the thickness direction of the sheet shape through the conductive particles. As an anisotropic conductive adhesive utilizing radical polymerization reaction by ultraviolet irradiation, a method disclosed in JP-A-60-262436 is known.
These anisotropic conductive adhesives utilizing radical polymerization reaction are adhesive compositions in which a small amount of a photopolymerization initiator that generates radicals by ultraviolet rays or the like is added by combining several monomers and oligomers having an acryloyl group. However, until now, anisotropic conductive adhesives utilizing radical polymerization reactions have had the problem that high connection reliability with both heat resistance and adhesive strength cannot be obtained. Specifically, in order to improve the heat resistance of the cured adhesive and obtain sufficient connection reliability under high temperature conditions, the amount of polyfunctional acrylic monomer is increased and the reactivity in the adhesive is increased. It was necessary to increase the concentration of the acrylic group as the group. However, since this method is a cured product having high elasticity and small elongation, the adhesive force is reduced, peeling of the connection interface easily proceeds, and sufficient connection reliability cannot be obtained. In addition, the adhesive strength can be improved by adding a silane coupling agent to the adhesive, but in order to promote the reaction of the silane coupling agent and improve the adhesive strength, the connection temperature is increased or the connection time is increased. Therefore, the characteristics of the photo-curable adhesive, which can be cured at a low temperature in a short time, could not be fully utilized.
[0003]
[Problems to be solved by the invention]
The present invention has been made in view of such a situation, and intends to provide a novel configuration of an electrode connecting adhesive excellent in adhesive strength and connection reliability.
[0004]
[Means for Solving the Problems]
In other words, the present invention is for electrode connection that is placed between the electrode on the first electronic component and the electrode of the second electronic component, and is used for the purpose of electrically connecting and bonding the opposed electrodes. In the adhesive, a photoacid generator, a silane coupling agent, a radical polymerizable acrylic compound, and a photoreaction initiator are essential components. The radical polymerizable acrylic compound contains a urethane acrylate oligomer and an acryloyl group or a methacryloyl group. The present invention relates to an electrode connecting adhesive containing at least one radical polymerizable acrylic compound and a connection structure of a fine electrode using the electrode connecting adhesive. Further, the present invention provides an electrode for placing an electrode connecting adhesive between the electrode on the first electronic component and the electrode of the second electronic component, and electrically connecting and bonding the opposed electrodes. The electrode connecting adhesive comprises a photoacid generator, a silane coupling agent, a radical polymerizable acrylic compound, a photoreaction initiator as essential components, and the radical polymerizable acrylic compound Contains a urethane acrylate oligomer and a radically polymerizable acrylic compound having three or more acryloyl groups or methacryloyl groups, and is connected to the electrode connecting adhesive in a heated and pressurized state at the time of connection between the electrodes. The present invention relates to an electrode connection method for performing ultraviolet irradiation.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The present invention uses a photoacid generator, a silane coupling agent, a radical polymerizable acrylic compound, and a photoreaction initiator as essential components of an electrode connecting adhesive, and has high adhesive force even at low temperature connection conditions, and connection reliability. An excellent electrode connecting adhesive can be obtained.
The photoacid generator is a substance that absorbs light and generates an acid. The generated acid acts as a reaction catalyst for the hydrolysis condensation reaction of the alkoxysilane group of the silane coupling agent, and the photocurable adhesive for electrode connection with the adhesive. Adhesive strength with the substrate which is the adherend can be increased. Therefore, the reaction proceeds more quickly at a lower temperature than when the hydrolysis and condensation reaction of the alkoxysilane group of the silane coupling agent is advanced only by conventional heating, so that a high adhesive force can be obtained at a low temperature connection condition. Connection reliability can be improved.
As the photoacid generator, various sulfonium salts and iodonium salts can be used, but a sulfonium salt having a high catalytic activity is preferable because a larger reaction-promoting curing can be obtained.
As the silane coupling agent, various alkoxysilanes can be used, but those containing an acryloyl group undergo a polymerization reaction with the radically polymerizable acrylic compound of the adhesive component and become a part of the adhesive cured product. Since high adhesive force is obtained, it is preferable.
[0006]
As the radical-polymerizable acrylic compound, monomers or oligomers of various methacrylates or acrylate compounds having an acryloyl group are used. Among them, it is preferable to add one having two acryloyl groups in view of the elastic modulus and heat resistance of the cured adhesive.
Specifically, as the acrylic monomer, for example, one having an acrylic or methacrylic group at both ends of a polyethylene glycol or polypropylene glycol skeleton or one having an acryl or methacrylic group at both ends of a bisphenol skeleton can be used. In addition, heat resistance can be improved by adding an appropriate amount of three or more acryloyl groups such as trimethylolpropane trimethacrylate and tetramethylolmethanetetraacrylate. As the acrylic oligomer, oligomers such as polyester acrylate, epoxy acrylate, and urethane acrylate can be used.
As the photoreaction initiator, derivatives such as acetophenone, benzoin, and benzophenone can be used as the reaction initiator by ultraviolet rays, and derivatives such as dicarbonyl compounds, thioxanthone, and acylphosphine oxide can be used as the reaction initiator by visible light. In addition, it is preferable to use a photoreaction accelerator such as an amine compound in combination with these because the curing reaction can proceed more rapidly.
[0007]
Further, when a hydroxyl group-containing resin such as phenoxy resin, polyester, polyvinyl butyral, phenol resin or the like having a molecular weight of 10,000 or more is added as a part of the adhesive component, the toughness of the cured product by the polymer compound is increased and the adhesion by the hydroxyl group And reliability is improved. In particular, if an acrylic monomer having an isocyanate group is reacted with the hydroxyl group of the phenoxy resin and an acryl-modified phenoxy resin having an acryloyl group introduced in the side chain is used, it reacts with the acrylic resin in the adhesive at the time of connection. Can be improved. When the ratio of the acryloyl group to the bisphenol structure in the acrylic modified phenoxy resin is in the range of 0.1 to 1, a remarkable improvement in the heat resistance of the cured product is obtained, and the glass transition temperature of the cured product has a large proportion of the acryloyl group. As it gets higher. Therefore, the desired heat resistance can be obtained by adjusting the ratio of the acryloyl group to the bisphenol structure in the acrylic modified phenoxy resin. However, as the ratio of acryloyl groups increases, the toughness of the cured product tends to be impaired, and the ratio of acryloyl groups to the bisphenol structure is generally in the range of 0.1 to 0.5. Is obtained.
[0008]
Here, the ratio of the acryloyl group to the bisphenol structure represents the ratio of the number of bisphenol structures contained in the molecule to the number of acryloyl groups contained in the molecule. That is, when the number of bisphenol structures in the molecule is equal to the number of acryloyl groups in the molecule, the ratio of acryloyl groups to the bisphenol structure is 1, and the number of acryloyl groups in the molecule is relative to the number of bisphenol structures in the molecule. When the number is 1/10, the ratio of the acryloyl group to the bisphenol structure is 0.1. Moreover, it can be set as the film-form adhesive agent for electrode connection excellent in the handleability and pot life by adding a suitable amount of solid polymer compounds. The thickness of the film-like electrode connecting adhesive is not particularly limited, but the adhesive force and moisture resistance are improved by filling the unevenness of the electrode part to be connected with the adhesive. A thickness greater than or equal to the unevenness is suitable. Moreover, since it will become difficult to handle if it becomes thin, and manufacturing will become difficult by generation | occurrence | production of wrinkles etc., 0.005 mm-1 mm are suitable.
The glass transition temperature of the cured product bonded in this connection process varies depending on the ratio of the acryloyl group to the bisphenol structure of the acrylic modified phenoxy resin and the structure and compounding ratio of the acrylic monomer and acrylic oligo as described above. When the temperature is 100 ° C. or higher, there is no peeling of the connection part in an accelerated test such as a high-temperature and high-humidity test of 85 ° C. and 85% RH and a thermal shock test of −40 ° C. to 100 ° C., and particularly good connection reliability with low resistance. can get.
Further, by adding conductive particles to the electrode connecting adhesive, connection resistance is further reduced, and a highly reliable connection in which an increase in resistance in a high-temperature and high-humidity test or a heat cycle test is suppressed can be obtained. The conductive particles can be used alone or in combination with metal plating resin particles in which a plating layer of Ni or Au is provided on the surface of metal particles such as Ni or resin particles. As the material of these conductive particles, an optimum material is selected and used according to characteristics such as hardness and deformability of the electrode to be connected. The particle size is selected according to the fineness of the circuit to be connected, but the particle size of each particle needs to be as uniform as possible.
Further, the electrode connecting adhesive of the present invention can be applied not only to the electrode connecting material described above but also to an interlayer connecting material of a multilayer circuit member.
[0009]
【Example】
Hereinafter, details will be described based on examples of the present invention, but the present invention is not limited thereto. The materials and evaluation methods used in the examples and comparative examples are shown below.
An aromatic sulfonium salt (manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sun-Aid) was used as the photoacid generator. As the silane coupling agent, γ-methacryloxypropyltrimethoxysilane (made by Toray Dow Corning Silicone Co., Ltd., trade name SZ6030) was used. As a radical polymerizable acrylic compound, urethane acrylate oligomer (made by Shin-Nakamura Chemical Co., Ltd., trade name UA-122P) is used, and tetramethylol methane triacrylate (made by Shin-Nakamura Chemical Co., Ltd.), which is a polyfunctional acrylic monomer, Trade name A-TMM-3L) was used. 4% benzophenone (reagent) was added as a photoreaction initiator, and 1% 4,4-bisdiethylaminobenzophenone (made by Hodogaya Chemical Co., Ltd., trade name EAB) was added as a photoreaction accelerator. As the hydroxyl group-containing resin, polyvinyl butyral resin (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name PVB3000K) and phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name PKHC) were used. As the acrylic modified phenoxy resin, a resin obtained by reacting phenoxy resin (trade name PKHC, manufactured by Union Carbide Co., Ltd.) and 2-methacryloyloxyethyl isocyanate (product name, Karenz MOI, manufactured by Showa Denko KK) was used.
The conductive particles used were polystyrene spherical particles having an average particle diameter of 5 μm provided with a 0.1 μm Ni layer and an Au layer on the surface.
The liquid electrode connecting adhesive was applied on the electrode and connected using a syringe-like dispenser. The film-like adhesive for electrode connection was formed by coating an adhesive diluted with a solvent of methyl ethyl ketone or ethyl acetate on a Teflon film with an applicator and then drying to form a film having a thickness of about 20 μm. When connecting, a film-like adhesive for electrode connection was transferred from the Teflon film to the electrode surface, and the Teflon film was removed for use.
[0010]
The connection reliability was evaluated by bonding an FPC having 100 copper electrodes arranged in parallel on a polyimide film with a line width of 50 μm, a pitch of 100 μm and a thickness of 18 μm, and a glass substrate having an ITO electrode with a surface resistance of 20Ω / □. This was performed using a sample connected by an agent. The connection was performed by irradiating the adhesive with ultraviolet rays of about 2 J / cm 2 at a pressure of 20 kg / cm 2 in a pressurized heating state at 130 ° C. for 20 seconds or 150 ° C. for 30 seconds. Ultraviolet rays were irradiated by using a high-pressure mercury lamp as a light source and introducing ultraviolet rays into the adhesive at the connection portion by an optical fiber.
The cured adhesive formed into a film was subjected to dynamic viscoelasticity measurement, the glass transition temperature was measured, and used as an index of heat resistance. The cured adhesive was prepared by using a cured product that was irradiated with UV rays at 130 ° C. for 2J.
The connection resistance was measured for each line with a measurement current of 1 mA, and the average value was taken as the connection resistance. Reliability evaluation was performed in 1000 cycles of a thermal cycle test in which samples were alternately placed in each test bath at −40 ° C. and 100 ° C.
For the evaluation of adhesive strength, the adhesion of FPC to ITO glass was measured by a 90-degree peel test.
[0011]
Example 1
Uniform mixing of 60% urethane acrylate oligomer (weight, the same applies below), 22% tetramethylolmethane triacrylate, 10% silane coupling agent, 3% photoacid generator, 4% photoreaction initiator, 1% photoreaction accelerator Then, an adhesive for circuit connection was produced.
[0012]
Example 2
Uniform mixing of 40% polyvinyl butyral resin, 30% urethane acrylate oligomer, 12% tetramethylol methane triacrylate, 10% silane coupling agent, 3% photoacid generator, 4% photoreaction initiator, 1% photoreaction accelerator Then, an adhesive for film-like circuit connection was produced.
[0013]
Example 3
Uniform mixing of 40% phenoxy resin, 30% urethane acrylate oligomer, 12% tetramethylol methane triacrylate, 10% silane coupling agent, 3% photoacid generator, 1% photoreaction accelerator and adhesive for film circuit connection An agent was prepared.
[0014]
Example 4
40% acrylic modified phenoxy resin with 0.1% acryloyl group to bisphenol structure, 30% urethane acrylate oligomer, 12% tetramethylol methane triacrylate, 10% silane coupling agent, 3% photoacid generator, photoreaction 4% of the initiator and 1% of the photoreaction accelerator were uniformly mixed to prepare an adhesive for film-like circuit connection.
[0015]
Example 5
40% acrylic modified phenoxy resin with a ratio of acryloyl group to bisphenol structure of 0.3, 30% urethane acrylate oligomer, 12% tetramethylol methane triacrylate, 10% silane coupling agent, 3% photoacid generator, photoreaction 4% of the initiator and 1% of the photoreaction accelerator were uniformly mixed to prepare an adhesive for film-like circuit connection.
[0016]
Example 6 to Example 10
Examples obtained by adding 5% by volume of conductive particles to Examples 1 to 5 were designated as Examples 6 to 10, respectively.
[0017]
Comparative Example 1 to Comparative Example 10
Comparative Examples 1 to 10 were those in which the photoacid generators of Examples 1 to 10 were not added.
Table 1 shows the glass transition temperature, the adhesive strength at 130 ° C. for 20 seconds, the adhesive strength at 150 ° C. for 30 seconds, the initial connection resistance, and the connection resistance after the reliability test in each Example and Comparative Example. Any of the electrode connecting adhesives according to the present invention is excellent in adhesive force even in connection conditions at a relatively low temperature, and excellent in connection reliability.
[0018]
[Table 1]
【The invention's effect】
The adhesive for electrode connection according to
The adhesive for electrode connection according to
The adhesive for electrode connection according to claim 3 has the effects according to
The adhesive for electrode connection according to claim 4 is suitable for obtaining the film-like adhesive for electrode connection having the effects of
The electrode connecting adhesive according to
The adhesive for electrode connection according to claim 6 has the effects of
The adhesive for electrode connection according to claim 7 exhibits the effects according to
The adhesive for electrode connection according to claim 8 has the effects according to
The adhesive for electrode connection according to claim 9 has the effects of
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electrode connection structure using an electrode connection adhesive containing conductive particles according to the present invention.
[Explanation of symbols]
DESCRIPTION OF
Claims (19)
光酸発生剤、シランカップリング剤、ラジカル重合性アクリル化合物、光反応開始剤を必須成分としてなり、
前記ラジカル重合性アクリル化合物が、ウレタンアクリレートオリゴマと、アクリロイル基もしくはメタクリロイル基を３つ以上持つラジカル重合性アクリル化合物と、を含有する、電極接続用接着剤。In the adhesive for electrode connection used for the purpose of placing between the electrode on the first electronic component and the electrode of the second electronic component, and electrically connecting and bonding the opposed electrodes,
A photoacid generator, a silane coupling agent, a radical polymerizable acrylic compound, and a photoreaction initiator are essential components.
An adhesive for electrode connection, wherein the radical polymerizable acrylic compound contains a urethane acrylate oligomer and a radical polymerizable acrylic compound having three or more acryloyl groups or methacryloyl groups .
前記電極接続用接着剤が、光酸発生剤、シランカップリング剤、ラジカル重合性アクリル化合物、光反応開始剤を必須成分としてなるものであり、
前記ラジカル重合性アクリル化合物が、ウレタンアクリレートオリゴマと、アクリロイル基もしくはメタクリロイル基を３つ以上持つラジカル重合性アクリル化合物と、を含有するものであり、
電極間の接続時に、加熱加圧状態で前記電極接続用接着剤への紫外線照射を行う、電極の接続方法。An electrode connecting method for placing an electrode connecting adhesive between an electrode on a first electronic component and an electrode on a second electronic component, electrically connecting and bonding the opposed electrodes. ,
The electrode connecting adhesive comprises a photoacid generator, a silane coupling agent, a radical polymerizable acrylic compound, and a photoreaction initiator as essential components.
The radical polymerizable acrylic compound contains a urethane acrylate oligomer and a radical polymerizable acrylic compound having three or more acryloyl groups or methacryloyl groups,
An electrode connection method in which ultraviolet rays are applied to the electrode connecting adhesive in a heated and pressurized state at the time of connection between the electrodes.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03948298A JP4151101B2 (en) | 1998-02-23 | 1998-02-23 | Electrode connecting adhesive, fine electrode connecting structure using the same, and electrode connecting method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03948298A JP4151101B2 (en) | 1998-02-23 | 1998-02-23 | Electrode connecting adhesive, fine electrode connecting structure using the same, and electrode connecting method |
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|---|---|---|---|
| JP2008076341A Division JP2008258607A (en) | 2008-03-24 | 2008-03-24 | Adhesive for electrode connection, connection structure of fine electrode using this, and connection method of electrode |
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| JPH11236535A JPH11236535A (en) | 1999-08-31 |
| JP4151101B2 true JP4151101B2 (en) | 2008-09-17 |
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Cited By (1)
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| JP2010100840A (en) * | 2008-09-24 | 2010-05-06 | Hitachi Chem Co Ltd | Adhesive film and circuit connection material |
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| JP4815648B2 (en) * | 1999-09-01 | 2011-11-16 | 日立化成工業株式会社 | Film adhesive for circuit connection |
| JP4752107B2 (en) * | 2000-11-29 | 2011-08-17 | 日立化成工業株式会社 | Film adhesive for circuit connection, circuit terminal connection structure, and circuit terminal connection method |
| JP4788038B2 (en) * | 2000-12-28 | 2011-10-05 | 日立化成工業株式会社 | Adhesive composition, circuit terminal connection method using the same, and circuit terminal connection structure |
| JP4720073B2 (en) * | 2003-08-07 | 2011-07-13 | 日立化成工業株式会社 | Adhesive composition, adhesive composition for circuit connection, connector and semiconductor device |
| JP5140996B2 (en) * | 2006-08-29 | 2013-02-13 | 日立化成工業株式会社 | Adhesive composition, circuit connection material, circuit member connection structure, and semiconductor device |
| JP5211343B2 (en) * | 2008-07-11 | 2013-06-12 | フジコピアン株式会社 | Photocurable adhesive composition and polarizing plate using the same |
| JP5716881B2 (en) | 2008-10-04 | 2015-05-13 | スリーボンドファインケミカル株式会社 | Photocurable adhesive composition |
| JP5504225B2 (en) * | 2010-08-31 | 2014-05-28 | 積水化学工業株式会社 | Anisotropic conductive material and connection structure |
| JP5735381B2 (en) * | 2010-08-31 | 2015-06-17 | 積水化学工業株式会社 | Curable composition, method for producing curable composition, and connection structure |
| JP6425899B2 (en) * | 2014-03-11 | 2018-11-21 | デクセリアルズ株式会社 | ANISOTROPIC CONDUCTIVE ADHESIVE, METHOD FOR MANUFACTURING CONNECTION AND METHOD FOR CONNECTING ELECTRONIC COMPONENTS |
| KR20180068899A (en) * | 2015-10-07 | 2018-06-22 | 세키스이가가쿠 고교가부시키가이샤 | Poly(vinyl acetal) resin composition, adhesive sheet, interlaminar filling material for touch panel, and laminate |
| JP2018065916A (en) * | 2016-10-19 | 2018-04-26 | デクセリアルズ株式会社 | Method for producing connection body |
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1998
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010100840A (en) * | 2008-09-24 | 2010-05-06 | Hitachi Chem Co Ltd | Adhesive film and circuit connection material |
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| JPH11236535A (en) | 1999-08-31 |
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