JP3871095B2 - Circuit board device manufacturing method - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は光硬化成分と導電性粒子を含有する回路接続材料を用いて、相対峙する電極同士が電気的に接続された回路板装置の製造法に関する。
【０００２】
【従来の技術】
フィルム状回路接続材料は、金属粒子等の導電性粒子を所定量含有した接着剤からなるもので、このフィルム状回路接続材料を電子部品と電極や回路の間に設け、加圧または加熱加圧を行うことによって、両者の電極同士が電気的に接続されると共に、隣接電極間の絶縁性を付与して、電子部品と回路とが接着固定されるものである。フィルム状回路接続材料に用いられる接着剤としては、スチレン系やポリエステル系等の熱可塑性物質や、エポキシ系やシリコーン系等の熱硬化性物質が知られている。これらの物質を含む接着剤を硬化させるには硬化剤が必要であり、さらにその硬化剤には、フィルム状回路接続材料の保存安定性を高めるために、常温では不活性であり、活性温度以上でのみ反応するという潜在性が伴っていなければならない。このため接着剤を硬化させるためには、樹脂成分の流動性の向上および硬化反応の促進のための加熱加圧が必要となる。すなわち、接着剤を溶融、流動させ、導電性粒子を変形して回路との接触面積を増大し、かつ回路部材との密着性を高めるために温度や圧力が必要となり、これらは接着剤の種類や硬化成分による。
この他にフィルム状以外の形態を有する回路接続材料としては、光硬化性樹脂を用いたペースト状材料が知られているが、これらの回路接続材料は加圧もしくは加熱加圧によって回路部材を接続し、その後光照射によって接着剤を硬化させることを特徴としている。
【０００３】
【発明が解決しようとする課題】
しかしながら、樹脂硬化の際の加熱加圧に伴う回路部材に対する熱や圧力の影響はその大小を問わず存在し、特に熱的な影響に関しては、回路部材自体への影響のみならず、回路部材接続時の影響も大きい。すなわち前者の場合、例えば液晶パネル等の回路部材を接続する際、偏光板等液晶パネル自体に対する影響が懸念され、これによって従来より低温での接続、あるいは従来より短時間での接続が要求されている。
また後者の場合、加熱加圧時の温度が高い条件で接続を行うと、対向する２つの回路部材が異なっておりそれぞれの熱膨張係数（α）の差が大きい場合には、回路の位置ずれが発生する可能性が高い。これは隣接回路間のピッチが狭くなるにつれてさらに発生確率が高くなる。
本発明は、光照射を併用することによって従来より低温での接続が可能で、回路部材に対する熱的影響を軽減し、かつ接続後における接続部の信頼性に優れ、さらには従来より有する簡便な取扱い性の品質に影響を与えないフィルム状回路接続材料を用い、相対峙する電極同士を電気的に接続することによって得られる回路板装置の製造法を提供するものである。
【０００４】
【課題を解決するための手段】
本発明は、少なくとも一方が光透過性を有する２つの回路部材である第一の接続端子を有する第一の回路部材と、第二の接続端子を有する第二の回路部材とを、第一の接続端子と第二の接続端子を対向して配置し、前記対向配置した第一の接続端子と第二の接続端子の間に回路接続材料を介在させ、一定時間の加熱加圧および一定時間の光照射を併用し、一定時間の加熱加圧の開始後、２〜５秒経過後に一定時間の光照射を開始し、光照射が行なわれている間は加熱加圧状態を保持することによって、前記対向配置した第一の接続端子と第二の接続端子を電気的に接続させた回路板装置の製造法であって、前記回路接続材料が（１）ラジカル重合性物質、（２）光照射によって活性ラジカルを発生する化合物、（３）フィルム形成能を有する高分子樹脂、（４）導電性粒子の各成分を必須とする光硬化フィルム状回路接続材料であることを特徴とするものである。
【０００５】
本発明において、回路部材としては半導体チップ、抵抗体チップ、コンデンサチップ等のチップ部品、プリント基板等の基板、ポリイミドやポリエステルを基材としたフレキシブル配線板、液晶パネル等ガラス上に酸化インジウム（ＩＴＯ）やクロム等で配線した透明電極等が用いられる。半導体チップや基板の電極パッド上には、めっきで形成されるバンプや金ワイヤの先端をトーチ等により溶融させ、金ボールを形成し、このボールを電極パッド上に圧着した後、ワイヤを切断して得られるワイヤバンプ等の突起電極を設け、接続端子として用いることができる。
【０００６】
これらの回路部材には接続端子が通常は多数（場合によっては単数でも良い）設けられており、少なくとも一方が光透過性を有する前記回路部材の少なくとも１組を、それらの回路部材に設けられた接続端子の少なくとも１部を対向配置し、対向配置した接続端子間に接着剤を介在させ、加熱加圧および光照射して対向配置した接続端子同士を電気的に接続して接続体とする。この時、光透過性を有する回路部材の厚みは、１．２ｍｍ以下が光透過性の面で好ましい。
また、光硬化性樹脂を含有する回路接続材料の形態をフィルム状とすることで、従来のペースト状回路接続材料に比べて取扱い性が優れている点や接続厚みの均一化が図れる点等で有利である。さらに、回路部材との密着性を高めるために、硬化反応がほとんど進行せず樹脂が流動する程度の加熱を行う場合、接続材料の加熱を行って接続端子−導電性粒子−接続端子間の導通を確保した後、冷却工程を導入することによって接続材料の溶融粘度を再上昇させることが可能であり、これによって加熱−冷却のみによる導電性粒子の圧接状態を維持し樹脂の固定が図れる。
【０００７】
本発明の製造法では、第一の接続端子と第二の接続端子とを対向配置し、その間に（１）ラジカル重合性物質、（２）光照射によって活性ラジカルを発生する化合物、（３）フィルム形成能を有する高分子樹脂、（４）導電性粒子を必須成分とする回路接続材料を介在させ、加熱加圧および光照射によって前記対向配置した第一の接続端子と第二の接続端子を電気的に接続させる。回路接続材料の硬化は主として光硬化によって行なわれるために、加熱加圧工程の役割としては、接着剤を溶融、流動させ、接続端子と導電性粒子が接触する部分周辺の樹脂成分を十分に排除し、接続端子間に導電性粒子を充分に圧接させることである、と考えることができる。このため接着剤のＴｇ以上、もしくは導電性粒子の十分な変形に必要な接着剤の流動が得られる温度まで加熱すればよく、その温度はフィルム形成材料である高分子樹脂の種類にもよるが、概ね８０〜１４０℃の範囲内である。これは従来の熱硬化性樹脂を硬化成分として用いているフィルム状回路接続材料の接続に必要な加熱温度である１５０〜１９０℃よりも低い。したがって上記方法によって回路部材の接続温度の低温化を図ることができる。
【０００８】
また（１）ラジカル重合性物質、（２）光照射によって活性ラジカルを発生する化合物、（３）フィルム形成能を有する高分子樹脂、（４）導電性粒子を必須成分とすることによって、光硬化が可能なフィルム状の回路接続材料を提供することが可能である。これは、用いる高分子樹脂は分子量が１０，０００以上であって常温で固形であり、フィルム形成能力が高いことに起因している。この高分子樹脂と光硬化性樹脂を混合することによって、従来の、光硬化性樹脂を用いた回路接続材料の短所であった、取扱い性の向上や接続厚みの均一化等を図ることが可能である。
さらには、加熱加圧と光照射を同時に行う場合は、接着剤の流動によって導電性粒子の接触を十分に行うために、溶融流動性と光照射能力との調整が必要である。ここでいう光照射能力は、用いる光照射装置の光源に依存しており、光量の少ない光源を使用している光照射装置の場合には、接着剤の硬化速度が遅くなり、その間に樹脂流動が十分に行なわれるため、加熱加圧と光照射を全く同時に行うことができる。また光量の多い光源を使用している光照射装置の場合には、樹脂流動を優先させるために加熱加圧工程と光照射工程の間に１〜数秒の間隔を設け、加熱加圧開始後に光照射を行うこともできる。この場合光照射を遅延して行うため、樹脂が流動し導電性粒子による接続端子の導通が確保された後、光量を増加して短時間で急速に硬化させてもよい。
【０００９】
一定時間の加熱加圧および一定時間の光照射を行う際の順序に関しては、前述した様に溶融流動性と光照射能力との調整を行い、加熱加圧と光照射を同時に開始し同時に終了するのが、その所要時間を考えると最も理想的であるが、より優れた接続信頼性を確実に得るには、加熱加圧工程と光照射工程との間に適当な間隔を設け、接着剤樹脂が十分に流動するための時間を確保する方法が最適である。設ける間隔は加熱加圧を開始し、接着剤樹脂の流動がほぼ完全に終了するまでの時間とするのが理想的であり、この場合０．５〜１０秒とするのが好ましいが、加熱加圧時間および接着剤樹脂の溶融粘度の点から２〜５秒とすることがより好ましい。
【００１０】
【発明の実施の形態】
本発明に用いるフィルム状回路接続材料としては（１）ラジカル重合性物質および（２）光照射によって活性ラジカルを発生する化合物から成る光硬化成分に、（３）フィルム形成能を有する高分子樹脂を混合した接着剤成分、そして（４）導電性粒子から成っており、接続材料をフィルム状とすることで回路部材接続時の取扱い性の向上を図ることができる。
【００１１】
本発明に用いるラジカル重合性物質としては、エポキシアクリレートオリゴマー、ウレタンアクリレートオリゴマー、ポリエーテルアクリレートオリゴマー、ポリエステルアクリレートオリゴマー等の光重合性オリゴマー、トリメチロールプロパントリアクリレート、ポリエチレングリコールジアクリレート、ポリアルキレングリコールジアクリレート、ペンタエリスリトールアクリレート２−シアノエチルアクリレート、シクロヘキシルアクリレート、ジシクロペンテニルアクリレート、ジシクロペンテニロキシエチルアクリレート、２（２−エトキシエトキシ）エチルアクリレート、２−エトキシエチルアクリレート、２−エチルヘキシルアクリレート、ｎ−ヘキシルアクリレート、２−ヒドロキシエチルアクリレート、ヒドロキシプロピルアクリレート、イソボルニルアクリレート、イソデシルアクリレート、イソオクチルアクリレート、ｎ−ラウリルアクリレート、２−メトキシエチルアクリレート、２−フェノキシエチルアクリレート、テトラヒドロフルフリールアクリレート、ネオペンチルグリコールジアクリレート、ジペンタエリスリトールヘキサアクリレート等の光重合性単官能および多官能アクリレートモノマー等といったアクリル酸エステル等、およびこれらと類似したｔーブチルアミノエチルメタクリレート、シクロヘキシルメタクリレート、ジシクロペンテニロキシエチルメタクリレート、２−ヒドロキシエチルメタクリレート、イソボルニルメタクリレート、イソデシルメタクリレート、ｎ−ラウリルアクリレート、ステアリルメタクリレート、トリデシルメタクリレート、グリシジルメタクリレート等の光重合性単官能および多官能メタクリレートモノマーといったメタクリル酸エステル等に代表される光重合型の樹脂があり、必要に応じてこれらの樹脂を単独あるいは混合して用いてもよいが、接着剤硬化物の硬化収縮を抑制し、柔軟性を与えるためにはウレタンアクリレートオリゴマーを配合するのが好ましい。また上述した光重合性オリゴマーは高粘度であるために、粘度調整のために低粘度の光重合性多官能アクリレートモノマー等のモノマーを配合するのが好ましいが、その際には所望の接着剤特性を得るために１種あるいは２種類以上を混合して用いてもよい。
【００１２】
これらの光硬化性樹脂は光照射によって活性ラジカルを発生する化合物を用いて重合、硬化させる。本発明に用いる光開始剤としてはベンゾインエチルエーテル、イソプロピルベンゾインエーテル等のベンゾインエーテル、ベンジル、ヒドロキシシクロヘキシルフェニルケトン等のベンジルケタール、ベンゾフェノン、アセトフェノン等のケトン類およびその誘導体、チオキサントン類、ビスイミダゾール類等があり、これらの光開始剤に必要に応じてアミン類、イオウ化合物、リン化合物等の増感剤を任意の比で添加してもよい。この際、用いる光源の波長や所望の硬化特性等に応じて最適な光開始剤を選択する必要がある。
【００１３】
本発明に用いるフィルム形成能を有する高分子樹脂としては、含有した場合の取扱い性がよく硬化時の応力緩和に優れるものが好ましく、水酸基等の官能基を有する場合には被着体との接着性が向上するためより好ましい。各ポリマーをラジカル重合性の官能基で変性したものがより好ましい。これらポリマーの分子量は１００００以上が好ましいが１００００００以上になると混合性が悪くなる。また、これらの光硬化性樹脂とポリスチレン、ポリエチレン、ポリビニルブチラール、ポリビニルホルマール、ポリイミド、ポリアミド、ポリエステル、ポリ塩化ビニル、ポリフェニレンオキサイド、尿素樹脂、メラミン樹脂、フェノール樹脂、キシレン樹脂、エポキシ樹脂、ポリイソシアネート樹脂、フェノキシ樹脂等があり、これらを１種あるいは２種類以上を混合して用いることができる。
また、被着体が無機物の場合にはシランカップリング剤を接着剤樹脂に混合して被着体との接着強度を高めることが可能である。シランカップリング剤としてはビニルトリクロルシラン、ビニルトリエトキシシラン、ビニル−トリス−（βメトキシエトキシ）シラン、γ−メタクリロキシプロピルトリメトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、γ−アミノプロピルトリエトキシシラン、β−（３，４エポキシシクロヘキシル）エチルトリメトキシシラン、イソシアン酸プロピルトリエトキシシラン等があるが、光硬化性樹脂との反応性を高めるにはγ−メタクリロキシプロピルトリメトキシシランを用いるのがより好ましい。
【００１４】
硬化に用いる光は、一般的に広く使用されている紫外線を用いることができ、水銀ランプ、メタルハライドランプ、無電極ランプ等で発生させることができる。また、硬化反応としてラジカル反応を用いた場合、酸素が反応禁止剤として作用するので、光照射の雰囲気中の酸素量は光硬化性樹脂の硬化に影響を与える。これは光硬化性樹脂、光開始剤、増感剤等の種類や濃度にも大きく左右されるので、個々の配合系で詳細に検討する必要がある。
【００１５】
本発明に用いる導電性粒子としては、Ａｕ、Ａｇ、Ｎｉ、Ｃｕ、はんだ等の金属粒子やカーボン等があり、これらおよび非導電性のガラス、セラミック、プラスチック等に前記した導通層を被覆等によって形成したものでもよい。プラスチックを核とした場合や熱溶融金属粒子の場合、加熱加圧によって変形性を有するので接続時に電極との接触面積が増加し信頼性が向上するので好ましい。導電性粒子は、接着剤成分１００体積部に対して、０．１〜３０体積部の広範囲で用途によって使い分ける。過剰な導電性粒子による隣接回路の短絡等を防止するためには、０．２〜１５体積部とするのがより好ましい。この時の導電性粒子の平均粒径は、その添加量にもよるが１〜１５μｍとするのがより好ましい。また導電性粒子の圧縮弾性率は、加熱加圧および光照射を中断した時に、接着剤の弾性による粒子の復元を抑制するために、１０００〜１００００ＭＰａの範囲内とすることが好ましい。
【００１６】
本発明には用途に応じて無機充填剤、有機充填剤、白色顔料、重合抑制剤、増感剤およびその組合せから選択される添加物を含有してもよい。その添加量としては接着剤樹脂成分１００重量部に対して１〜１００重量部が好ましいが、添加物の種類や性質が得られる回路板の信頼性に悪影響を及ぼす可能性がない、あるいは著しく低くなるような範囲内で用いる必要がある。
【００１７】
【実施例】
以下に、本発明を実施例に基づいて詳細に説明するが、本発明はこれに限定されるものではない。
参考例１
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、平均分子量４５，０００）４０ｇを、重量比でトルエン（沸点１１０．６℃、ＳＰ値８．９０）／酢酸エチル（沸点７７．１℃、ＳＰ値９．１０）＝５０／５０の混合溶剤６０ｇに溶解して、固形分４０％の溶液とした。ラジカル重合性物質は、エポキシアクリレートオリゴマー（新中村化学工業株式会社製、商品名ＮＫオリゴＥＡ−１０２０）およびアクリレートモノマー（新中村化学工業株式会社製、商品名ＮＫエステルＡ−ＴＭＭ−３Ｌ）を、３／１の重量比で用いた。光開始剤はベンゾフェノンを用い、これに増感剤として４，４'−ビスジエチルアミノベンゾフェノン（保土ケ谷化学工業株式会社製、商品名ＥＡＢ）を、光開始剤／増感剤＝５／１となるように混合して用いた。またポリスチレンを核とする粒子の表面に、厚み０．２μｍのニッケル層を設け、このニッケル層の外側に、厚み０．０２μｍの金層を設け、平均粒径５μｍ、比重２．５の導電性粒子を作製した。固形重量比でフェノキシ樹脂５０、ラジカル重合性物質５０、光開始剤５、増感剤１となるように配合し、さらに導電性粒子を３体積％配合分散させ、厚み８０μｍのフッ素樹脂フィルムに塗工装置を用いて塗布し、７０℃、１０分の熱風乾燥によって接着剤層の厚みが２０μｍのフィルム状回路接続材料を得た。上記製法によって得たフィルム状回路接続材料を用いて、ライン幅５０μｍ、ピッチ１００μｍ、厚み１８μｍの銅回路を５００本有するフレキシブル回路板（ＦＰＣ）と、０．２μｍの酸化インジウム（ＩＴＯ）の薄層を形成したガラス（厚み１．１ｍｍ、表面抵抗２０Ω／□）とを、紫外線照射併用型熱圧着装置（加熱方式：コンスタントヒート型、東レエンジニアリング株式会社製）を用いて１３０℃、２ＭＰａで２０秒間の加熱加圧およびＩＴＯガラス側からの紫外線照射を同時に行って幅２ｍｍにわたり接続し、時間経過後圧力開放して、接続体を作製した。接着剤に照射される紫外線照射量は２．０Ｊ／ｃｍ２とした。この時、あらかじめＩＴＯガラス上に、フィルム状回路接続材料の接着面を貼り付けた後、７０℃、０．５ＭＰａで５秒間加熱加圧して仮接続し、その後、フッ素樹脂フィルムを剥離してもう一方の被着体であるＦＰＣと接続した。
【００１８】
実施例１
参考例１で使用したフィルム状回路接続材料を用いて、ライン幅５０μｍ、ピッチ１００μｍ、厚み１８μｍの銅回路を５００本有するフレキシブル回路板（ＦＰＣ）と、０．２μｍの酸化インジウム（ＩＴＯ）の薄層を形成したガラス（厚み１．１ｍｍ、表面抵抗２０Ω／□）とを、紫外線照射併用型熱圧着装置（加熱方式：コンスタントヒート型、東レエンジニアリング株式会社製）を用いて１３０℃、２ＭＰａで２０秒間の加熱加圧およびＩＴＯガラス側からの紫外線照射を同時に行って幅２ｍｍにわたり接続し、時間経過後圧力開放して、接続体を作製した。接着剤に照射される紫外線照射量は２．０Ｊ／ｃｍ２とした。この時、あらかじめＩＴＯガラス上に、フィルム状回路接続材料の接着面を貼り付けた後、７０℃、０．５ＭＰａで５秒間加熱加圧して仮接続し、その後、フッ素樹脂フィルムを剥離してもう一方の被着体であるＦＰＣと接続した。また２０秒間の接続の際、加熱加圧のみを開始して３秒経過した後１７秒間の紫外線照射を開始し、加熱加圧２０秒後に２工程が同時に終了するようにした。
【００１９】
実施例２
参考例１で使用したフィルム状回路接続材料のラジカル重合性物質を、ウレタンアクリレートオリゴマー（新中村化学工業株式会社製、商品名ＮＫオリゴＵＡ−５１２）およびアクリレートモノマー（Ａ−ＴＭＭ−３Ｌ）に代えた他は、実施例１と同様にして接続体を作製した。
【００２０】
実施例３
参考例１で使用したフィルム状回路接続材料の導電性粒子を、平均粒径５μｍのニッケル粒子（大同特殊綱株式会社製、商品名ＤＳＰ３１０１、比重８．５）に代えた他は、実施例１と同様にして接続体を作製した。
【００２１】
実施例４
参考例１で使用したフィルム状回路接続材料の光開始剤を、ビスイミダゾール型光開始剤（黒金化成製、２，２'−ビス（ｏ−クロロフェニル）４，４'，５，５'−テトラフェニル１，２−ビイミダゾール）に代えた他は、実施例１と同様にして接続体を作製した。
【００２２】
実施例５
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、平均分子量４５，０００）４０ｇを、重量比でトルエン（沸点１１０．６℃、ＳＰ値８．９０）／酢酸エチル（沸点７７．１℃、ＳＰ値９．１０）＝５０／５０の混合溶剤６０ｇに溶解して、固形分４０％の溶液とした。ラジカル重合性物質は、エポキシアクリレートオリゴマー（新中村化学工業株式会社製、商品名ＮＫオリゴＥＡ−１０２０）およびアクリレートモノマー（新中村化学工業株式会社製、商品名ＮＫエステルＡ−ＴＭＭ−３Ｌ）を、３／１の重量比で用いた。光開始剤はベンゾフェノンを用い、これに増感剤として４，４'−ビスジエチルアミノベンゾフェノン（保土ケ谷化学工業株式会社製、商品名ＥＡＢ）を、光開始剤／増感剤＝５／１となるように混合して用いた。またポリスチレンを核とする粒子の表面に、厚み０．２μｍのニッケル層を設け、このニッケル層の外側に、厚み０．０２μｍの金層を設け、平均粒径５μｍ、比重２．５の導電性粒子を作製した。固形重量比でフェノキシ樹脂５０、ラジカル重合製物質５０、光開始剤５、増感剤１となるように配合し、さらに導電性粒子を３体積％、および無機充填剤（無水シリカ微粒子、１次粒子平均径約１２ｎｍ）を５重量％配合分散し、厚み８０μｍのフッ素樹脂フィルムに塗工装置を用いて塗布し、７０℃、１０分の熱風乾燥によって接着剤層の厚みが２０μｍのフィルム状回路接続材料を得た。上記製法によって得たフィルム状回路接続材料を用いて、ライン幅５０μｍ、ピッチ１００μｍ、厚み１８μｍの銅回路を５００本有するフレキシブル回路板（ＦＰＣ）と、０．２μｍの酸化インジウム（ＩＴＯ）の薄層を形成したガラス（厚み１．１ｍｍ、表面抵抗２０Ω／□）とを、紫外線照射併用型熱圧着装置（加熱方式：コンスタントヒート型、東レエンジニアリング株式会社製）を用いて１３０℃、２ＭＰａで１０秒間の加熱加圧およびＩＴＯガラス側からの紫外線照射を同時に行って幅２ｍｍにわたり接続し、時間経過後圧力開放して、接続体を作製した。接着剤に照射される紫外線照射量は２．０Ｊ／ｃｍ２とした。この時、あらかじめＩＴＯガラス上に、フィルム状回路接続材料の接着面を貼り付けた後、７０℃、０．５ＭＰａで５秒間加熱加圧して仮接続し、その後、フッ素樹脂フィルムを剥離してもう一方の被着体であるＦＰＣと接続した。また１０秒間の接続の際、加熱加圧のみを開始して２秒経過した後８秒間の紫外線照射を開始し、加熱加圧１０秒後に２工程が同時に終了するようにした。
【００２３】
比較例１
参考例１で使用したフィルム状回路接続材料を用いて、ライン幅５０μｍ、ピッチ１００μｍ、厚み１８μｍの銅回路を５００本有するフレキシブル回路板（ＦＰＣ）と、０．２μｍの酸化インジウム（ＩＴＯ）の薄層を形成したガラス（厚み１．１ｍｍ、表面抵抗２０Ω／□）とを、紫外線照射併用型熱圧着装置（加熱方式：コンスタントヒート型、東レエンジニアリング株式会社製）を用いて１３０℃、２ＭＰａで１０秒間の加熱加圧およびＩＴＯガラス側からの紫外線照射を同時に行って幅２ｍｍにわたり接続し、時間経過後圧力開放して、接続体を作製した。紫外線照射量は５．０Ｊ／ｃｍ２とした。この時、あらかじめＩＴＯガラス上に、フィルム状回路接続材料の接着面を貼り付けた後、７０℃、０．５ＭＰａで５秒間加熱加圧して仮接続し、その後、フッ素樹脂フィルムを剥離してもう一方の被着体であるＦＰＣと接続した。
【００２４】
参考例２
参考例１で使用したフィルム状回路接続材料を用いて、ライン幅５０μｍ、ピッチ１００μｍ、厚み１８μｍの銅回路を５００本有するフレキシブル回路板（ＦＰＣ）と、０．２μｍの酸化インジウム（ＩＴＯ）の薄層を形成したガラス（厚み１．１ｍｍ、表面抵抗２０Ω／□）とを、紫外線照射併用型熱圧着装置（加熱方式：コンスタントヒート型、東レエンジニアリング株式会社製）を用いて１３０℃、２ＭＰａで５秒間の加熱加圧およびＩＴＯガラス側からの紫外線照射を同時に行って幅２ｍｍにわたり接続し、時間経過後圧力開放して、接続体を作製した。紫外線照射量は０．６Ｊ／ｃｍ２とした。この時、あらかじめＩＴＯガラス上に、フィルム状回路接続材料の接着面を貼り付けた後、７０℃、０．５ＭＰａで５秒間加熱加圧して仮接続し、その後、フッ素樹脂フィルムを剥離してもう一方の被着体であるＦＰＣと接続した。また、５秒間の接続の際、加熱加圧のみを開始して２秒経過した後３秒間の紫外線照射を開始した。そして加熱加圧開始５秒後に加熱工程のみを終了するようにした。
【００２５】
比較例２
参考例１で使用したフィルム状回路接続材料の配合樹脂であるフェノキシ樹脂と、マイクロカプセル型潜在性硬化剤を含有する液状エポキシ樹脂を、固形重量比でフェノキシ樹脂５０、液状エポキシ樹脂５０となるように配合し、さらに参考例１で用いた導電性粒子を３体積％配合分散させ、厚み８０μｍのフッ素樹脂フィルムに塗工装置を用いて塗布し、７０℃、１０分の熱風乾燥によって接着剤層の厚みが２０μｍのフィルム状回路接続材料を得た。上記製法によって得たフィルム状回路接続材料を用いて、ライン幅５０μｍ、ピッチ１００μｍ、厚み１８μｍの銅回路を５００本有するフレキシブル回路板（ＦＰＣ）と、０．２μｍの酸化インジウム（ＩＴＯ）の薄層を形成したガラス（厚み１．１ｍｍ、表面抵抗２０Ω／□）とを、コンスタントヒート型熱圧着装置（当社製）を用いて１３０℃、２ＭＰａで２０秒間加熱加圧して幅２ｍｍにわたり接続し、時間経過後圧力開放して、これを接続終了とした。この時、あらかじめＩＴＯガラス上に、フィルム状回路接続材料の接着面を貼り付けた後、７０℃、０．５ＭＰａで５秒間加熱加圧して仮接続し、その後、フッ素樹脂フィルムを剥離してもう一方の被着体であるＦＰＣと接続した。
【００２６】
比較例３
光硬化性樹脂は、エポキシアクリレートオリゴマー（新中村化学工業株式会社製、商品名ＮＫオリゴＥＡ−１０２０）およびアクリレートモノマー（新中村化学工業株式会社製、商品名ＮＫエステルＡ−ＴＭＭ−３Ｌ）を、３／１の重量比で用い、光開始剤にはベンゾフェノンを用い、これに増感剤として４，４'−ビスジエチルアミノベンゾフェノン（保土ケ谷化学工業株式会社製、商品名ＥＡＢ）を、光開始剤／増感剤＝５／１となるように混合して用いた。また、ポリスチレンを核とする粒子の表面に、厚み０．２μｍのニッケル層を設け、このニッケル層の外側に、厚み０．０２μｍの金層を設け、平均粒径５μｍ、比重２．５の導電性粒子を作製した。これらを用い、固形重量比で光硬化性樹脂１００、光開始剤５、増感剤１となるように配合し、さらに導電性粒子を３体積％配合分散させ、ペースト状回路接続材料を得た。上記製法によって得たペースト状回路接続材料を用いて、ライン幅５０μｍ、ピッチ１００μｍ、厚み１８μｍの銅回路を５００本有するフレキシブル回路板（ＦＰＣ）と、０．２μｍの酸化インジウム（ＩＴＯ）の薄層を形成したガラス（厚み１．１ｍｍ、表面抵抗２０Ω／□）とを、パルスヒート型熱圧着装置（日本アビオニクス株式会社製）を用いて１３０℃、２ＭＰａで２０秒間加熱加圧して幅２ｍｍにわたり接続し、時間経過後圧力開放して、これを接続終了とした。この時、あらかじめＩＴＯガラス上に、ペースト状回路接続材料を適量塗布し、もう一方の被着体であるＦＰＣと接続した。上記方法によって得た接続体に、紫外線照射装置（コンベア移動式、ウシオ電機株式会社製）を用いて、ＩＴＯガラス側から紫外線を照射して接続体を作製した。この時の紫外線照射量は２．０Ｊ／ｃｍ２とした。
【００２７】
参考例１〜２、実施例１〜５、比較例１〜３で得た接続体について初期抵抗、接着性および回路の補修性について評価した。初期抵抗については、回路部材の接続後、上記接続部を含むＦＰＣの隣接回路間の抵抗値を、マルチメータで測定した。測定電流は１ｍＡとし、抵抗値は隣接回路間の抵抗１５０点の平均（ｘ＋３σ）で示した。ＦＰＣならびにＩＴＯガラスに対する接着性については、接着強度をＪＩＳ−Ｚ０２３７に準じて９０度剥離法で測定し、評価した。測定装置は東洋ボールドウィン株式会社製テンシロンＵＴＭ−４（剥離速度５０ｍｍ／ｍｉｎ、２５℃）を使用した。加熱加圧と紫外線照射を同時に開始、終了している参考例１では、初期抵抗、接着強度のいずれも良好な値を示した。また実施例１の場合、２０秒の加熱加圧、１７秒の紫外線照射を３秒の間隔を設けて行っているため、接着剤樹脂が加熱によって十分に流動し、接続端子と導電性粒子との接触面積がより大きくなるため、特に初期抵抗に関して参考例１よりさらに良好な接続特性を有する回路板が得られた。さらに導電性粒子、ラジカル重合性物質、光開始剤を代えた実施例２〜４においても良好な接続状態の確保が可能であった。さらに無機充填剤を添加した実施例５の場合、無添加の場合とほぼ同等の良好な初期接着強度が得られたことから、充填剤による光硬化反応の阻害はほとんど起こらず、また耐湿信頼性試験処理後の接着強度においても、無機充填剤の応力緩和作用によって無添加の場合に比べて向上する。
【００２８】
一方、光照射量５．０Ｊ／ｃｍ２の条件下で加熱加圧と紫外線照射を同時に行った比較例１では、接着剤の硬化反応が樹脂の流動よりも早く進行するため、導電性粒子が回路部材に十分に接触しておらず、導通不良となった。参考例２の場合は３秒の紫外線照射のみで接着剤樹脂の硬化を行っており、その照射量も０．６Ｊ／ｃｍ ２ しかなく反応不足を招いているため、初期抵抗に関しては良好であるが初期接着強度は芳しくなかった。熱硬化性樹脂を主成分とした接着剤を用いている比較例２では、１３０℃、２ＭＰａ、２０秒の接続条件では接着剤の反応率が低くなるため、十分な硬化が得られず、接着強度がかなり低くなり初期抵抗も高くなった。比較例３の場合には、フィルム形成性を付与する高分子樹脂が含有されていないために、取扱い性の点でフィルム状材料より不利であった。
【００２９】
【発明の効果】
本発明によれば、接着剤に光硬化性樹脂をおよび導電性粒子を必須成分とするフィルム状回路接続材料を介在させ、加熱加圧と同時に、あるいは加熱加圧後に光照射によって回路部材を接続するため、接続に要する温度を従来より低くすることが可能で、優れた接着強度や良好な電気的導通を得ることができ、優れた信頼性を有する回路板装置を得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a circuit board device in which electrodes facing each other are electrically connected to each other using a circuit connecting material containing a photocuring component and conductive particles.
[0002]
[Prior art]
The film-like circuit connection material is made of an adhesive containing a predetermined amount of conductive particles such as metal particles. This film-like circuit connection material is provided between an electronic component and an electrode or circuit, and is pressurized or heated and pressurized. By performing the above, both electrodes are electrically connected to each other, and insulation between adjacent electrodes is imparted, so that the electronic component and the circuit are bonded and fixed. As adhesives used for the film-like circuit connecting material, thermoplastic materials such as styrene and polyester, and thermosetting materials such as epoxy and silicone are known. In order to cure the adhesive containing these substances, a curing agent is required. Further, the curing agent is inactive at room temperature and is higher than the activation temperature in order to enhance the storage stability of the film-like circuit connecting material. It must be accompanied by the potential to react only with. For this reason, in order to cure the adhesive, it is necessary to apply heat and pressure to improve the fluidity of the resin component and accelerate the curing reaction. That is, the temperature and pressure are required to melt and flow the adhesive, deform the conductive particles to increase the contact area with the circuit, and improve the adhesion to the circuit member. Depending on the curing component.
In addition, paste materials using photo-curing resins are known as circuit connection materials having forms other than film-like, but these circuit connection materials connect circuit members by pressurization or heating and pressurization. The adhesive is then cured by light irradiation.
[0003]
[Problems to be solved by the invention]
However, the effects of heat and pressure on the circuit members due to heating and pressurization during resin curing exist regardless of their size. Especially regarding the thermal effects, not only the effects on the circuit members themselves, but also the connection of the circuit members. The influence of time is also great. That is, in the former case, for example, when connecting circuit members such as a liquid crystal panel, there is a concern about the influence on the liquid crystal panel itself such as a polarizing plate, which requires a connection at a lower temperature than in the past or a connection in a shorter time than the conventional. Yes.
In the latter case, if the connection is performed under a condition where the temperature at the time of heating and pressurization is high, the two circuit members facing each other are different, and if the difference between the respective thermal expansion coefficients (α) is large, the circuit position shifts. Is likely to occur. This is more likely to occur as the pitch between adjacent circuits becomes narrower.
The present invention enables connection at a lower temperature than in the past by using light irradiation in combination, reduces the thermal influence on the circuit member, is excellent in reliability of the connection part after connection, and has a simpler than in the past. The present invention provides a method for producing a circuit board device obtained by electrically connecting electrodes facing each other using a film-like circuit connecting material that does not affect the quality of handleability.
[0004]
[Means for Solving the Problems]
The present invention provides a first circuit member having a first connection terminal, at least one of which is two circuit members having light transparency, and a second circuit member having a second connection terminal, The connection terminal and the second connection terminal are arranged to face each other, and a circuit connection material is interposed between the first connection terminal and the second connection terminal that are arranged to face each other. Combined with light irradiationAfter 2 to 5 seconds have elapsed after the start of heating and pressing for a certain time, light irradiation for a certain time is started and the heating and pressing state is maintained while the light irradiation is performed.A method of manufacturing a circuit board device in which the first connection terminal and the second connection terminal arranged opposite to each other are electrically connectedBecauseThe circuit connection material is essential for each component of (1) a radical polymerizable substance, (2) a compound that generates an active radical when irradiated with light, (3) a polymer resin having film-forming ability, and (4) conductive particles. ToLight-curing film circuitIt is characterized by being a connecting material.
[0005]
In the present invention, as circuit members, chip parts such as semiconductor chips, resistor chips, capacitor chips, substrates such as printed boards, flexible wiring boards based on polyimide and polyester, indium oxide (ITO) on glass such as liquid crystal panels ) Or a transparent electrode wired with chromium or the like. On the electrode pad of the semiconductor chip or substrate, the bump formed by plating or the tip of the gold wire is melted with a torch or the like to form a gold ball, and after the ball is pressed onto the electrode pad, the wire is cut. Such as wire bumpsProtrusionAn electrode can be provided and used as a connection terminal.
[0006]
These circuit members are usually provided with a large number of connection terminals (or a single connection terminal in some cases), and at least one of the circuit members having light transparency is provided on those circuit members. At least one part of the connection terminals is arranged oppositely, an adhesive is interposed between the oppositely arranged connection terminals, and the connection terminals arranged opposite to each other by heating and pressurizing and irradiating light are electrically connected to form a connection body. At this time, the thickness of the light transmissive circuit member is preferably 1.2 mm or less in terms of light transmissive property.
In addition, by making the form of the circuit connection material containing the photocurable resin into a film shape, the handling property is superior to the conventional paste-like circuit connection material, and the connection thickness can be made uniform. It is advantageous. Furthermore, in order to improve the adhesiveness with the circuit member, when heating is performed to such an extent that the curing reaction hardly proceeds and the resin flows, conduction between the connection terminal-conductive particle-connection terminal is performed by heating the connection material. It is possible to re-increase the melt viscosity of the connection material by introducing a cooling step after securing the above, whereby the pressure contact state of the conductive particles only by heating and cooling can be maintained and the resin can be fixed.
[0007]
In the production method of the present invention, the first connection terminal and the second connection terminal are arranged to face each other, (1) a radical polymerizable substance between them, (2) a compound that generates an active radical by light irradiation, (3) A polymer resin having film-forming ability; and (4) a circuit connection material containing conductive particles as an essential component, and a first connection terminal and a second connection terminal arranged to face each other by heating and pressurization and light irradiation. Connect electrically. Since the circuit connection material is mainly cured by photocuring, the role of the heating and pressurizing process is to melt and flow the adhesive and sufficiently eliminate the resin component around the area where the connection terminals and conductive particles are in contact. It can be considered that the conductive particles are sufficiently pressed between the connection terminals. For this reason, it may be heated to Tg of the adhesive or a temperature at which the flow of the adhesive necessary for sufficient deformation of the conductive particles can be obtained, and the temperature depends on the type of polymer resin that is a film forming material. The temperature is generally within the range of 80 to 140 ° C. This is lower than 150 to 190 ° C., which is a heating temperature necessary for connection of a film-like circuit connecting material using a conventional thermosetting resin as a curing component. Therefore, the connection temperature of the circuit member can be lowered by the above method.
[0008]
In addition, (1) a radical polymerizable substance, (2) a compound that generates an active radical when irradiated with light, (3) a polymer resin having film-forming ability, and (4) a conductive particle as an essential component, photocuring It is possible to provide a film-like circuit connection material that can be used. This is because the polymer resin used has a molecular weight of 10,000 or more, is solid at room temperature, and has a high film forming ability. By mixing this polymer resin and photo-curing resin, it is possible to improve the handleability and make the connection thickness uniform, which is a disadvantage of conventional circuit connection materials using photo-curing resin. It is.
Furthermore, when performing heating and pressurization and light irradiation at the same time, it is necessary to adjust the melt fluidity and the light irradiation ability in order to sufficiently contact the conductive particles by the flow of the adhesive. The light irradiation capability here depends on the light source of the light irradiation device to be used, and in the case of a light irradiation device using a light source with a small amount of light, the curing rate of the adhesive is slowed, Therefore, heating and pressurization and light irradiation can be performed at the same time. In the case of a light irradiation device using a light source with a large amount of light, an interval of 1 to several seconds is provided between the heating and pressurizing step and the light irradiation step in order to prioritize resin flow, and light is emitted after the start of heating and pressing. Irradiation can also be performed. In this case, since the light irradiation is delayed, after the resin flows and the conduction of the connection terminal by the conductive particles is ensured, the amount of light may be increased to rapidly cure in a short time.
[0009]
Regarding the order of heating and pressing for a certain time and light irradiation for a certain timeTheAs mentioned above, adjusting the melt fluidity and light irradiation ability, and starting and ending the heating and pressurization and light irradiation at the same time are the most ideal in terms of the required time, but better In order to reliably obtain the connection reliability, it is optimal to provide an appropriate interval between the heating and pressurizing step and the light irradiation step to ensure a sufficient time for the adhesive resin to flow sufficiently. It is ideal to set the interval between heating and pressurization and the time until the flow of the adhesive resin is almost completely completed. In this case, it is preferably 0.5 to 10 seconds. The pressure time and the melt viscosity of the adhesive resin are more preferably 2 to 5 seconds.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The film-like circuit connecting material used in the present invention includes (1) a radical polymerizable substance and (2) a photocuring component composed of a compound that generates an active radical by light irradiation, and (3) a polymer resin having film-forming ability. It is composed of the mixed adhesive component and (4) conductive particles. By making the connecting material into a film shape, it is possible to improve the handleability when connecting circuit members.
[0011]
The radical polymerizable substance used in the present invention includes photopolymerizable oligomers such as epoxy acrylate oligomers, urethane acrylate oligomers, polyether acrylate oligomers, polyester acrylate oligomers, trimethylolpropane triacrylate, polyethylene glycol diacrylate, polyalkylene glycol diacrylate. , Pentaerythritol acrylate 2-cyanoethyl acrylate, cyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, 2 (2-ethoxyethoxy) ethyl acrylate, 2-ethoxyethyl acrylate, 2-ethylhexyl acrylate, n-hexyl acrylate 2-hydroxyethyl acrylate, hydroxypro Acrylate, isobornyl acrylate, isodecyl acrylate, isooctyl acrylate, n-lauryl acrylate, 2-methoxyethyl acrylate, 2-phenoxyethyl acrylate, tetrahydrofurfryl acrylate, neopentyl glycol diacrylate, dipentaerythritol hexaacrylate Acrylic esters such as photopolymerizable monofunctional and polyfunctional acrylate monomers, and the like, and t-butylaminoethyl methacrylate, cyclohexyl methacrylate, dicyclopentenyloxyethyl methacrylate, 2-hydroxyethyl methacrylate, Nyl methacrylate, isodecyl methacrylate, n-lauryl acrylate, stearyl methacrylate, tride There are photopolymerization resins typified by methacrylic acid esters such as photopolymerizable monofunctional and polyfunctional methacrylate monomers such as methacrylic acid and glycidyl methacrylate, and these resins can be used alone or as a mixture as required. Although it is good, in order to suppress the curing shrinkage of the cured adhesive and to provide flexibility, it is preferable to add a urethane acrylate oligomer. In addition, since the above-mentioned photopolymerizable oligomer has a high viscosity, it is preferable to blend a monomer such as a low-viscosity polyfunctional acrylate monomer for adjusting the viscosity. In order to obtain 1 type, you may use 1 type or in mixture of 2 or more types.
[0012]
These photocurable resins are polymerized and cured using a compound that generates active radicals upon irradiation with light. Photoinitiators used in the present invention include benzoin ethers such as benzoin ethyl ether and isopropyl benzoin ether, benzyl ketals such as benzyl and hydroxycyclohexyl phenyl ketone, ketones such as benzophenone and acetophenone and derivatives thereof, thioxanthones, and bisimidazoles Sensitizers such as amines, sulfur compounds and phosphorus compounds may be added to these photoinitiators in any ratio as necessary. At this time, it is necessary to select an optimal photoinitiator according to the wavelength of the light source to be used, desired curing characteristics, and the like.
[0013]
The polymer resin having film-forming ability used in the present invention preferably has good handleability when contained and is excellent in stress relaxation during curing, and adheres to an adherend when it has a functional group such as a hydroxyl group. It is more preferable because of improved properties. What modified each polymer with the radically polymerizable functional group is more preferable. The molecular weight of these polymers is preferably 10,000 or more, but if they are 1,000,000 or more, the mixing property is deteriorated. In addition, these photocurable resins and polystyrene, polyethylene, polyvinyl butyral, polyvinyl formal, polyimide, polyamide, polyester, polyvinyl chloride, polyphenylene oxide, urea resin, melamine resin, phenol resin, xylene resin, epoxy resin, polyisocyanate resin There are phenoxy resins and the like, and these can be used alone or in combination of two or more.
Further, when the adherend is an inorganic substance, it is possible to increase the adhesive strength with the adherend by mixing a silane coupling agent with the adhesive resin. As silane coupling agents, vinyltrichlorosilane, vinyltriethoxysilane, vinyl-tris- (βmethoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltri There are ethoxysilane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, propyltriethoxysilane isocyanate, etc., but γ-methacryloxypropyltrimethoxysilane is used to increase the reactivity with the photocurable resin. Is more preferable.
[0014]
The light used for curing can be ultraviolet rays that are widely used in general, and can be generated by a mercury lamp, a metal halide lamp, an electrodeless lamp, or the like. Further, when a radical reaction is used as the curing reaction, oxygen acts as a reaction inhibitor, so the amount of oxygen in the light irradiation atmosphere affects the curing of the photocurable resin. Since this greatly depends on the type and concentration of the photocurable resin, photoinitiator, sensitizer, etc., it is necessary to examine in detail for each compounding system.
[0015]
As the conductive particles used in the present invention, there are metal particles such as Au, Ag, Ni, Cu, solder, carbon, etc., and these and non-conductive glass, ceramics, plastics, etc. are coated with the conductive layer described above. It may be formed. In the case of using plastic as a core or hot-melt metal particles, it is preferable because it has deformability by heating and pressurization, so that the contact area with the electrode is increased at the time of connection and the reliability is improved. The conductive particles are selectively used in a wide range of 0.1 to 30 parts by volume with respect to 100 parts by volume of the adhesive component. In order to prevent an adjacent circuit from being short-circuited by excessive conductive particles, the amount is more preferably 0.2 to 15 parts by volume. The average particle size of the conductive particles at this time is preferably 1 to 15 μm, although it depends on the amount of the conductive particles added. The compression elastic modulus of the conductive particles is preferably in the range of 1000 to 10,000 MPa in order to suppress the recovery of particles due to the elasticity of the adhesive when heating and pressurization and light irradiation are interrupted.
[0016]
The present invention may contain an additive selected from an inorganic filler, an organic filler, a white pigment, a polymerization inhibitor, a sensitizer, and combinations thereof depending on the application. The addition amount is preferably 1 to 100 parts by weight with respect to 100 parts by weight of the adhesive resin component, but there is no possibility of adversely affecting the reliability of the circuit board from which the kind and properties of the additive are obtained, or extremely low. It is necessary to use within such a range.
[0017]
【Example】
Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited thereto.
Reference example1
40 g of phenoxy resin (trade name PKHC, manufactured by Union Carbide Co., Ltd., average molecular weight 45,000) in weight ratio with toluene (boiling point 110.6 ° C., SP value 8.90) / ethyl acetate (boiling point 77.1 ° C., SP Value 9.10) = dissolved in 60 g of 50/50 mixed solvent to obtain a solution having a solid content of 40%. The radical polymerizable substance includes an epoxy acrylate oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name NK Oligo EA-1020) and an acrylate monomer (manufactured by Shin Nakamura Chemical Co., Ltd., trade name NK Ester A-TMM-3L). It was used at a weight ratio of 3/1. Benzophenone is used as the photoinitiator, and 4,4′-bisdiethylaminobenzophenone (made by Hodogaya Chemical Co., Ltd., trade name EAB) is used as the sensitizer so that the photoinitiator / sensitizer = 5/1. Used in combination. Further, a nickel layer having a thickness of 0.2 μm is provided on the surface of particles having polystyrene as a core, and a gold layer having a thickness of 0.02 μm is provided on the outside of the nickel layer. The conductivity is an average particle diameter of 5 μm and a specific gravity of 2.5. Particles were made. Phenoxy resin 50 by radical weight ratio, radical polymerizationsexIt mix | blends so that it may become the substance 50, the photoinitiator 5, and the sensitizer 1, Furthermore, electroconductive particle is mix | blended and disperse | distributed 3 volume%, It apply | coats to an 80-micrometer-thick fluororesin film using a coating device, 70 degreeC, A film-like circuit connecting material having an adhesive layer thickness of 20 μm was obtained by hot-air drying for 10 minutes. A flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm, and a thin layer of 0.2 μm of indium oxide (ITO) using the film-like circuit connecting material obtained by the above manufacturing method Glass (thickness 1.1 mm, surface resistance 20 Ω / □) is used at 130 ° C. and 2 MPa for 20 seconds using an ultraviolet irradiation combined thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.). The heating and pressurization and the ultraviolet irradiation from the ITO glass side were simultaneously performed to connect over a width of 2 mm, and the pressure was released after the lapse of time to prepare a connection body. The amount of UV irradiation applied to the adhesive is 2.0 J / cm2It was. At this time, after adhering the adhesive surface of the film-like circuit connecting material on the ITO glass in advance, the film is temporarily connected by heating and pressing at 70 ° C. and 0.5 MPa for 5 seconds, and then the fluororesin film is peeled off. It connected with FPC which is one to-be-adhered body.
[0018]
Example1
referenceA flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm, and a thin layer of 0.2 μm indium oxide (ITO) using the film-like circuit connecting material used in Example 1 Glass (thickness 1.1 mm, surface resistance 20 Ω / □) is used at 130 ° C. and 2 MPa for 20 seconds using an ultraviolet irradiation combined thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.). The heating and pressurization and the ultraviolet irradiation from the ITO glass side were simultaneously performed to connect over a width of 2 mm, and the pressure was released after the lapse of time to prepare a connection body. The amount of UV irradiation applied to the adhesive is 2.0 J / cm2It was. At this time, after adhering the adhesive surface of the film-like circuit connecting material on the ITO glass in advance, the film is temporarily connected by heating and pressing at 70 ° C. and 0.5 MPa for 5 seconds, and then the fluororesin film is peeled off. It connected with FPC which is one to-be-adhered body. When connecting for 20 seconds, only heating and pressurization was started, and after 3 seconds had elapsed, ultraviolet irradiation was started for 17 seconds, and after 20 seconds of heating and pressurization, the two steps were completed simultaneously.
[0019]
Example2
referenceThe radical polymerizable substance of the film-like circuit connecting material used in Example 1 was replaced with a urethane acrylate oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name NK Oligo UA-512) and an acrylate monomer (A-TMM-3L). Other examples1A connected body was produced in the same manner as described above.
[0020]
Example3
referenceExample 1 except that the conductive particles of the film-like circuit connecting material used in Example 1 were replaced with nickel particles having an average particle diameter of 5 μm (Daido Special Tuna Co., Ltd., trade name DSP3101, specific gravity 8.5).1A connected body was produced in the same manner as described above.
[0021]
Example4
referenceThe photoinitiator of the film-like circuit connecting material used in Example 1 is a bisimidazole-type photoinitiator (manufactured by Kurokin Kasei, 2,2′-bis (o-chlorophenyl) 4,4 ′, 5,5′-tetra Example 1, except that it was replaced with phenyl 1,2-biimidazole)1A connected body was produced in the same manner as described above.
[0022]
Example5
40 g of phenoxy resin (trade name PKHC, manufactured by Union Carbide Co., Ltd., average molecular weight 45,000) in weight ratio with toluene (boiling point 110.6 ° C., SP value 8.90) / ethyl acetate (boiling point 77.1 ° C., SP Value 9.10) = dissolved in 60 g of 50/50 mixed solvent to obtain a solution having a solid content of 40%. The radical polymerizable substance includes an epoxy acrylate oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name NK Oligo EA-1020) and an acrylate monomer (manufactured by Shin Nakamura Chemical Co., Ltd., trade name NK Ester A-TMM-3L). It was used at a weight ratio of 3/1. Benzophenone is used as the photoinitiator, and 4,4′-bisdiethylaminobenzophenone (made by Hodogaya Chemical Co., Ltd., trade name EAB) is used as the sensitizer so that the photoinitiator / sensitizer = 5/1. Used in combination. Further, a nickel layer having a thickness of 0.2 μm is provided on the surface of particles having polystyrene as a core, and a gold layer having a thickness of 0.02 μm is provided on the outside of the nickel layer. The conductivity is an average particle diameter of 5 μm and a specific gravity of 2.5. Particles were made. It is blended so that it becomes phenoxy resin 50, radical polymerization product 50, photoinitiator 5, and sensitizer 1 in a solid weight ratio, and further 3% by volume of conductive particles, and inorganic filler (anhydrous silica fine particles, primary particles). 5% by weight (average particle diameter of about 12 nm) is dispersed and applied to a fluororesin film having a thickness of 80 μm using a coating apparatus, and dried with hot air at 70 ° C. for 10 minutes to form a film circuit having an adhesive layer thickness of 20 μm. A connection material was obtained. A flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm, and a thin layer of 0.2 μm of indium oxide (ITO) using the film-like circuit connecting material obtained by the above manufacturing method The glass (thickness 1.1 mm, surface resistance 20 Ω / □) is formed at 130 ° C. and 2 MPa using an ultraviolet irradiation combined thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.).10Second heating and pressurization and UV irradiation from the ITO glass side were performed simultaneously to connect over a width of 2 mm, and after a lapse of time, the pressure was released to prepare a connection body. The amount of UV irradiation applied to the adhesive is 2.0 J / cm2It was. At this time, after adhering the adhesive surface of the film-like circuit connecting material on the ITO glass in advance, the film is temporarily connected by heating and pressing at 70 ° C. and 0.5 MPa for 5 seconds, and then the fluororesin film is peeled off. It connected with FPC which is one to-be-adhered body. In addition, at the time of connection for 10 seconds, only heating and pressurization was started, and after 2 seconds had elapsed, ultraviolet irradiation was started for 8 seconds, and two steps were completed simultaneously after 10 seconds of heating and pressurization.
[0023]
Comparative Example 1
referenceA flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm, and a thin layer of 0.2 μm indium oxide (ITO) using the film-like circuit connecting material used in Example 1 Glass (thickness 1.1 mm, surface resistance 20 Ω / □) is used at 130 ° C. and 2 MPa for 10 seconds using a thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.) with ultraviolet irradiation. The heating and pressurization and the ultraviolet irradiation from the ITO glass side were simultaneously performed to connect over a width of 2 mm, and the pressure was released after the lapse of time to prepare a connection body. UV irradiation is 5.0 J / cm2It was. At this time, after adhering the adhesive surface of the film-like circuit connecting material on the ITO glass in advance, the film is temporarily connected by heating and pressing at 70 ° C. and 0.5 MPa for 5 seconds, and then the fluororesin film is peeled off. It connected with FPC which is one to-be-adhered body.
[0024]
referenceExample 2
referenceA flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm, and a thin layer of 0.2 μm indium oxide (ITO) using the film-like circuit connecting material used in Example 1 The glass (thickness 1.1 mm, surface resistance 20 Ω / □) is formed using an ultraviolet irradiation combined type thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.) for 5 seconds at 130 ° C. and 2 MPa. Were heated and pressurized simultaneously and irradiated with ultraviolet rays from the ITO glass side to connect over a width of 2 mm, and after a lapse of time, the pressure was released to prepare a connection body. UV irradiation dose is 0.6 J / cm2It was. At this time, after adhering the adhesive surface of the film-like circuit connecting material on the ITO glass in advance, the film is temporarily connected by heating and pressing at 70 ° C. and 0.5 MPa for 5 seconds, and then the fluororesin film is peeled off. It connected with FPC which is one to-be-adhered body. In addition, at the time of connection for 5 seconds, only heating and pressurization was started, and after 2 seconds, ultraviolet irradiation for 3 seconds was started. Then, only the heating process was finished 5 seconds after the start of heating and pressing.
[0025]
Comparative example2
referenceThe phenoxy resin, which is a compounded resin of the film-like circuit connecting material used in Example 1, and the liquid epoxy resin containing the microcapsule-type latent curing agent are changed to a phenoxy resin 50 and a liquid epoxy resin 50 in a solid weight ratio. Blended and furtherreference3% by volume of the conductive particles used in Example 1 were dispersed and applied to a fluororesin film having a thickness of 80 μm using a coating apparatus, followed by drying with hot air at 70 ° C. for 10 minutes, and a film having an adhesive layer thickness of 20 μm. A circuit connection material was obtained. A flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm, and a thin layer of 0.2 μm of indium oxide (ITO) using the film-like circuit connecting material obtained by the above manufacturing method The glass (thickness 1.1 mm, surface resistance 20 Ω / □) formed was connected to a 2 mm width by heating and pressing at 130 ° C. and 2 MPa for 20 seconds using a constant heat type thermocompression bonding apparatus (manufactured by our company). After the elapse of time, the pressure was released, and this was terminated. At this time, after adhering the adhesive surface of the film-like circuit connecting material on the ITO glass in advance, the film is temporarily connected by heating and pressing at 70 ° C. and 0.5 MPa for 5 seconds, and then the fluororesin film is peeled off. It connected with FPC which is one to-be-adhered body.
[0026]
Comparative example3
The photo-curing resin includes an epoxy acrylate oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name NK Oligo EA-1020) and an acrylate monomer (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name NK Ester A-TMM-3L). It was used at a weight ratio of 3/1, benzophenone was used as the photoinitiator, and 4,4′-bisdiethylaminobenzophenone (made by Hodogaya Chemical Co., Ltd., trade name EAB) was used as the sensitizer. It was used by mixing so that sensitizer = 5/1. In addition, a nickel layer having a thickness of 0.2 μm is provided on the surface of particles having polystyrene as a nucleus, and a gold layer having a thickness of 0.02 μm is provided outside the nickel layer, and a conductive material having an average particle diameter of 5 μm and a specific gravity of 2.5. Particles were prepared. Using these, they were blended so as to be a photocurable resin 100, a photoinitiator 5 and a sensitizer 1 in a solid weight ratio, and further 3% by volume of conductive particles were dispersed and dispersed to obtain a paste-like circuit connection material. . A flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm, and a thin layer of 0.2 μm indium oxide (ITO) using the paste-like circuit connecting material obtained by the above manufacturing method Glass (thickness 1.1 mm, surface resistance 20 Ω / □) is connected to a width of 2 mm by heating and pressing at 130 ° C. and 2 MPa for 20 seconds using a pulse heat type thermocompression bonding apparatus (manufactured by Nippon Avionics Co., Ltd.). Then, the pressure was released after a lapse of time, and this was terminated. At this time, an appropriate amount of paste-like circuit connecting material was applied in advance on ITO glass and connected to the other adherend FPC. The connection body obtained by the above method was irradiated with ultraviolet rays from the ITO glass side using an ultraviolet irradiation device (conveyor moving type, manufactured by Ushio Electric Co., Ltd.) to prepare a connection body. The amount of UV irradiation at this time is 2.0 J / cm2It was.
[0027]
Reference Examples 1-2Example 15Comparative Examples 1 to3The connection body obtained in (1) was evaluated for initial resistance, adhesion and circuit repairability. Regarding the initial resistance, after connecting the circuit members, the resistance value between adjacent circuits of the FPC including the connecting portion was measured with a multimeter. The measurement current was 1 mA, and the resistance value was shown as the average (x + 3σ) of 150 resistances between adjacent circuits. About the adhesiveness with respect to FPC and ITO glass, adhesive strength was measured and evaluated by 90 degree peeling method according to JIS-Z0237. As a measuring device, Tensilon UTM-4 (peeling speed 50 mm / min, 25 ° C.) manufactured by Toyo Baldwin Co., Ltd. was used. Heating and pressing and UV irradiation are started and finished at the same timereferenceIn Example 1, both initial resistance and adhesive strength showed good values. Examples1In this case, since heating and pressurization for 20 seconds and ultraviolet irradiation for 17 seconds are performed at intervals of 3 seconds, the adhesive resin flows sufficiently by heating, and the contact area between the connection terminal and the conductive particles is increased. Especially with respect to initial resistancereferenceA circuit board having even better connection characteristics than Example 1 was obtained. Further, Examples in which conductive particles, radical polymerizable substances, and photoinitiators were replaced2~4In this case, it was possible to secure a good connection state. Example in which an inorganic filler was further added5In this case, good initial adhesive strength almost equal to that in the case of no addition was obtained, so that the photocuring reaction was hardly inhibited by the filler, and the adhesive strength after the moisture resistance reliability test treatment was also inorganic. It improves compared with the case of no addition by the stress relaxation action of the filler.
[0028]
On the other hand, light irradiation amount 5.0 J / cm2In Comparative Example 1 in which heating and pressurization and ultraviolet irradiation were performed simultaneously under the above conditions, since the curing reaction of the adhesive proceeds faster than the flow of the resin, the conductive particles are not sufficiently in contact with the circuit member, The continuity was poor.referenceIn the case of Example 2, the adhesive resin is cured only by UV irradiation for 3 seconds, and the irradiation amount is 0.6 J / cm. 2 However, since the reaction was insufficient, the initial resistance was good, but the initial adhesive strength was not good. Comparative example using an adhesive mainly composed of thermosetting resin2Then, since the reaction rate of the adhesive was low under the connection conditions of 130 ° C. and 2 MPa for 20 seconds, sufficient curing could not be obtained, the adhesive strength was considerably reduced, and the initial resistance was increased. Comparative example3In this case, since a polymer resin imparting film formability was not contained, it was disadvantageous from the film-like material in terms of handleability.
[0029]
【The invention's effect】
According to the present invention, a film-like circuit connection material containing a photocurable resin and conductive particles as essential components is interposed in an adhesive, and circuit members are connected by light irradiation at the same time as or after heating and pressing. Therefore, the temperature required for the connection can be made lower than before, excellent adhesive strength and good electrical continuity can be obtained, and a circuit board device having excellent reliability can be obtained.
Claims (2)
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| Application Number | Priority Date | Filing Date | Title |
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| JP08517098A JP3871095B2 (en) | 1998-03-31 | 1998-03-31 | Circuit board device manufacturing method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP08517098A JP3871095B2 (en) | 1998-03-31 | 1998-03-31 | Circuit board device manufacturing method |
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| JPH11284024A JPH11284024A (en) | 1999-10-15 |
| JP3871095B2 true JP3871095B2 (en) | 2007-01-24 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2002167569A (en) * | 2000-11-29 | 2002-06-11 | Hitachi Chem Co Ltd | Adhesive composition, adhesive composition for connecting circuit, connected unit and semiconductor device |
| 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 |
| US8062469B2 (en) | 2007-02-06 | 2011-11-22 | Nippon Kasei Chemical Company Limited | Adhesive resin composition and bonding method |
| CN104169389B (en) * | 2012-04-25 | 2018-07-13 | 日立化成株式会社 | Circuit connection material, circuit connection structure, adhesive film and coiling body |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3270773B2 (en) * | 1992-11-26 | 2002-04-02 | 京セラ株式会社 | Semiconductor element mounting method |
| JPH08325543A (en) * | 1995-06-05 | 1996-12-10 | Soken Chem & Eng Co Ltd | Anisotropically electroconductive adhesive |
| JP3976830B2 (en) * | 1997-03-27 | 2007-09-19 | 株式会社ブリヂストン | Anisotropic conductive film |
| JPH10338842A (en) * | 1997-06-06 | 1998-12-22 | Bridgestone Corp | Anisotropically conductive film |
| JP3965530B2 (en) * | 1997-06-06 | 2007-08-29 | 株式会社ブリヂストン | Anisotropic conductive film |
| JPH10338841A (en) * | 1997-06-06 | 1998-12-22 | Bridgestone Corp | Anisotropically conductive film |
| JP3922321B2 (en) * | 1998-01-06 | 2007-05-30 | 株式会社ブリヂストン | Anisotropic conductive film |
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