JP2004224942A

JP2004224942A - Anisotropic conductive elastic body composition and its preparing process

Info

Publication number: JP2004224942A
Application number: JP2003015556A
Authority: JP
Inventors: Shiro Tanami; 史郎田波; Norie Kazaoka; 紀江風岡; Hiromichi Endo; 裕理遠藤
Original assignee: Kinugawa Rubber Industrial Co Ltd
Current assignee: Kinugawa Rubber Industrial Co Ltd
Priority date: 2003-01-24
Filing date: 2003-01-24
Publication date: 2004-08-12

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anisotropic conductive composition having improved connection reliability and repair properties, and reducing manufacturing costs, and to provide its preparing process. <P>SOLUTION: The anisotropic conductive composition is made up by adding conductive particles to an insulating polymeric material followed by mixing and dispersing, and molding this into a thin film (e.g. applying the varnished mixture to the surface of a supported body and drying this to mold into a thin film). The average diameter D<SB>AVE.</SB>and diameter D of the conductive particle satisfy "0.5×d<D<SB>AVE.</SB><d" and "0.3×t≤D≤1.2×t", respectively wherein t is the thickness of the anisotropic conductive composition and d is the insulating width , namely the distance between respective ends of the objects to be connected facing each other. The conductive particles occupy 1.5 vol.% to 13 vol.% of the composition, and the insulating polymeric material uses a styrene-ethylene copolymer having a styrene content of 20% to 60%. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、相対峙する回路間に介在され、一方の回路の所望の端子と他方の回路の所望の端子とを導通させるための異方導電性弾性体組成物およびその製造方法であって、例えばＬＣＤ（液晶ディスプレイ）やＰＤＰ（プラズマディスプレイ）とＴＣＰ（テープキャリアパッケージ）との接続や、ＴＣＰとＰＣＢ（プリント回路基板）との接続等の各種微細な回路同士の電気的接続、半導体装置のバーンイン試験の装置に使用される異方導電性弾性体組成物に関するものである。
【０００２】
【従来の技術】
従来から、ＬＣＤやＰＤＰとＴＣＰとの接続、ＴＣＰとＰＣＢとの接続、ＦＰＣ（フレキシブルプリント基板）やＴＡＢ（テープオートボンディング）と液晶パネルのガラス基板上の端子（例えば、ＩＴＯ（スズインジウム酸化物）から成る端子）との接続等には異方導電性弾性体組成物（以下、異方導電性組成物と称する）が用いられ、この異方導電性組成物を相対峙（対向）する被接続対象間（例えば、ＬＣＤとＴＣＰとの各回路間）に介装して加熱および加圧することにより（各回路を接着することにより）、異方性導通を確保することができる。すなわち、各接続対象の面方向に隣接する端子（以下，隣接端子と称する）間では電気的絶縁性を保つ（クロストークを防止する）と共に、その相対峙する被接続対象の端子間を導通（一方の回路の各端子と他方の回路の各端子とをそれぞれ相互に導通）させることができる。
【０００３】
この異方導電性組成物が利用されてきた理由は、被接続対象となる回路（ＬＣＤ等の各回路）の耐熱性が低いこと，回路の微細化により隣接端子間で電気的にショートを起こす恐れがあること等により、単に半田付け等の従来の接続方法は適用できないためである。
【０００４】
従来の異方導電性組成物としては、接着性を有する樹脂（例えば、エポキシ系の樹脂，フェノール系の樹脂），硬化剤を主成分した接着剤に導電性物質（例えば導電性粒子）を分散させて成るもの（以下、接着剤組成物と称する）が広く知られており、主に熱可塑型と熱硬化型とに分類される。
【０００５】
なお、熱可塑型の接着剤組成物は、相対峙する回路を溶融溶着方式により接着するため、その接着工程に要する作業を比較的（熱硬化型のものと比較して）低温雰囲気下および短時間で行うことが可能であるが、使用される樹脂の耐湿性，耐薬品性，接続信頼性（異方性導通の精度）が低く、例えば長期環境試験に対する十分な耐久性が得られ難かった。
【０００６】
一方、熱硬化型の接着剤組成物については、一般的にエポキシ系樹脂を用いたものが広く知られ、熱可塑型のものと比較して耐湿性，耐薬品性，接続信頼性が良好で十分な硬化性が得られ、例えば潜在性硬化剤（例えば、ＢＦ_３アミン錯体，ジシアンジアミド，有機酸ヒドラジド，イミダゾール化合物等の硬化剤）を用いることにより保存安定性を向上できるが、その保存安定性が向上するに従って硬化性が低下し（硬化作業を長時間または高温雰囲気下で行う必要があり）、逆に硬化性を向上させると保存安定性が低下してしまう問題があった。
【０００７】
また、前記の接着剤組成物では、例えば接続工程において相対峙する被接続対象が所定の位置で接着されなかった場合、その各被接着対象（および接着剤組成物）を破損，損傷させずに剥離し再度接着または接合すること（以下、リペアメント性と称する）は困難であった。このため、十分な耐久性（機械的強度，耐湿性，耐薬品性，硬化性等），接続信頼性等を有すると共に、リペアメント性が良好な異方導電性組成物の開発が要望されていた。
【０００８】
近年、前記のリペアメント性を考慮した異方導電性組成物として、特開平９−２５９６３５号公報では２種類のフィルム（後述の第１，第２フィルム）から成る異方導電性組成物が開示されている。この異方導電性組成物は、まずエポキシ樹脂をトルエンで溶かして成る塗料に所定粒径の導電性粒子を所定量加え混合して得たものにより第１フィルム（例えば、ＩＴＯ電極端子側に位置するフィルム）を成膜する。また、硬化剤，硬化促進剤，熱可塑性樹脂をトルエンで溶かして成る塗料に所定粒径の導電性粒子を所定量加え混合して得たものにより第２フィルム（例えば、ＴＢＯ側に位置するフィルム）を成膜し、その第２フィルムと前記第１フィルムとを積層して異方導電性組成物（以下、積層構造組成物と称する）を得る。
【０００９】
前記のようにして構成された積層構造組成物は、例えばガラス基板上のＩＴＯ電極端子とＴＢＯの端子との間に介在（少なくとも第２フィルムがＩＴＯ電極端子側に位置するように介在）させ両端子間を加熱圧着し、その加熱圧着によって前記第１フィルム，第２フィルムにおいて溶融・混合して硬化反応させることにより、各フィルムの両端子間において導電性粒子の位置が固定され、両端子間の接続信頼性を確保することができるものである。また、前記の加熱圧着の際、前記第１フィルム，第２フィルムが完全には溶融・混合されず、積層構造組成物におけるＩＴＯ電極界面付近は溶剤可溶の熱可塑性樹脂成分が多く占めるため、積層構造組成物を容易に剥離できリペアメント性が高いものとされている。
【００１０】
【特許文献１】
特開平９−２５９６３５号公報（段落［０００９］〜［００１５］）。
【００１１】
また、特開２００２−１８００１２号公報では、エポキシカップリング剤，アリル変性シアヌレートを含有した異方導電性組成物が開示され、カップリング効果（化学的結合）の向上により接続信頼性と共にリペアメント性を確保できるものとされている。
【００１２】
【特許文献２】
特開２００２−１８００１２号公報（段落［００１５］，［００３４］〜［００３７］）。
【００１３】
前記異方導電性組成物は、前記のように例えばＬＣＤとＴＣＰとの各回路間の接続に用いたものの他に、例えば半導体装置のバーンイン試験の装置（被接続対象が半導体装置の電極とＩＣ検査用基板の電極端子）に用いられたものが知られている。従来のバーンイン試験では、半導体装置の電極，リードとＩＣ検査用基板の電極端子とを接続するためにＩＣソケットが用いられ、そのＩＣソケットは例えば半導体装置が装填可能な装填部と、その装填部に固接される電極端子と、ソケット本体の側部や底部に電極端子，導線を介して固接されるリード，ピンと、装填部の表面側開口部に対してヒンジ等により取り付けられる蓋部材とから構成されていた。
【００１４】
しかし、従来のＩＣソケットの場合、電極端子，リード，ピン等が必要であるため部品点数が多く、その組立工程が煩雑であった。また、前記ＩＣソケットはＩＣ検査用基板に対して半田付け等により接続する必要（すなわち、検査工程の増加）があった。さらに、前記のピンが設けられたＩＣソケットの場合、ＩＣ検査用基板に対してピン用のスルーホールを穿設する必要があり、そのＩＣ検査用基板の設計が煩雑になってしまう問題があった。
【００１５】
一方、異方導電性組成物を用いたものとして、例えば特開２００１−２７３９６０号公報では、エラストマーの薄膜中にワイヤ（金等）を貫通するように充填（半導体装置の電極に相当する位置に充填）されて成る異方導電性組成物（エラストマーコネクタ；以下、ワイヤ組成物と称する）をソケット本体の装填部におけるＩＣ検査用基板側開口部に固設して構成されたＩＣソケットが開示されている。このＩＣソケットの装填部に装填された半導体装置の各電極，各リードは、前記ワイヤ組成物を介してそれぞれＩＣ検査用基板の電極端子と導通し、半導体装置の隣接する各電極間，各リード間においては絶縁性を保つことができる。
【００１６】
【特許文献３】
特開２００１−２７３９６０号公報（段落［０００５］〜［００１３］）。
【００１７】
また、特開平７−１７４７８８号公報では、支持ブロックの厚さ方向に貫通する支持孔の軸方向に対して往復動自在に設けられ半導体装置の電極と接触する先端部が形成された導電性針状体と、ゴムマトリックス中に導電性粒子が分散されて成りＩＣ検査用基板と前記支持ブロック（導電性針状体の後端部側）との間に介在される異方導電性組成物と、を構成した装置が開示されている。この装置の導電性針状体を披検査対象である半導体装置の電極に接触させると、その導電性針状体の後端部が異方導電性組成物の弾発付勢力に抗して異方導電性組成物中に没入し、その没入により圧縮された領域の異方導電性組成物中の導電性粒子（複数個の導電性粒子）を介して前記半導体装置の電極とＩＣ検査用基板の電極端子とが導通する。
【００１８】
【特許文献４】
特開平７−１７４７８８号公報（段落［０００８］，［０００９］，図１乃至図４）。
【００１９】
【発明が解決しようとする課題】
しかしながら、前記のように相対峙する被接続対象の接続（例えばＬＣＤとＴＣＰとの各回路間の接続，半導体装置のバーンイン試験の装置）に用いられていた異方導電性組成物は、以下に示すような問題があった。
【００２０】
前記の積層構造組成物の場合は、２種類のフィルムを積層する必要があるため製造工程数の増加により生産コストが高くなってしまうと共に、積層構造組成物の第１フィルムは例えばＴＡＢ表面に加熱圧着（および溶融混合）する工程を経て硬化反応を起こすため、その硬化反応後の第１フィルムはＴＡＢ表面の形状を反映してしまう。すなわち、積層構造組成物をＩＴＯ電極端子から剥離することは容易であるが、その積層構造組成物において使用前の形状を維持できないため十分なリペアメント性を得ることができなかった。
【００２１】
エポキシカップリング剤，アリル変性シアヌレートを含有した異方導電性組成物においては、化学的結合の強化により接続信頼性を向上できるが、この異方導電性組成物は加熱圧着により接着して用いられるため、十分なリペアメント性が得られなかった（なお、特開２００２−１８００１２号公報では、リペアメント性に関する技術的対策等が何ら開示されていない）。
【００２２】
半導体装置のバーンイン試験の装置に用いられるワイヤ組成物の場合、製造工程数（未硬化ゴムシート間にワイヤを挟みプレス硬化する工程、その硬化物を切断する工程、その切断物をプレートにより位置制御する工程、絶縁性エラストマーを用いた金型成形する工程等），部品点数が多いため製造コストが高くなってしまうと共に、そのワイヤ（ワイヤの先端部）により例えば半導体装置のレジスト層等を損傷させてしまう恐れがあった。また、前記ワイヤと半導体装置の電極との接触により半田紛が生じ易く、その半田紛がワイヤ組成物に付着すると接続不良等を起こしてしまう問題があった。さらに、ワイヤ組成物からシリコーンオイルが浸出することがあり、そのシリコーンオイルが半導体装置に付着すると、そのバーンイン試験後の半田実装時において半田濡れ性が低下してしまう。
【００２３】
導電性針状体を備えた支持ブロックと併用される異方導電性組成物においては、その導電性針状体による圧縮量が大きい場合（導電性針状体が異方導電性組成物中に没入し、その没入した領域の導電性粒子の全てが互いに接触した場合）に異方性導通が達成されるため、半導体装置に対する導電性針状体の圧接力を大きく設定する必要がある。このため、バーンイン試験を繰り返し行うと、異方導電性組成物の耐久性が低下すると共に異方導電性組成物から導電性粒子が離脱し短絡してしまう恐れがある。また、回路の微細化等により半導体装置の各電極間の距離が短い場合（すなわち、各導電性針状体間の距離が短い場合）、異方導電性組成物の支持ブロック側の全面が圧縮され、クロストークが起こってしまう。
【００２４】
本発明は前記課題に基づいてなされたものであり、相対峙する被接続対象の接続（例えばＬＣＤとＴＣＰとの各回路間の接続，半導体装置のバーンイン試験の装置）において接続信頼性，リペアメント性を確保すると共に製造コストを低減する異方導電性組成物およびその製造方法を提供することにある。
【００２５】
【課題を解決するための手段】
本発明は前記の課題の解決を図るものであり、請求項１記載の発明は、少なくとも絶縁性高分子材料，導電性粒子（例えば、表面に導電性の良好な金属が被覆された粉体）を含んだ混合物から成り、相対峙する被接続対象の接続に用いられる異方導電性弾性体組成物（例えば薄膜状の異方導電性弾性体組成物）において、前記導電性粒子の平均粒径，粒径は、前記の相対峙する被接続対象の各端子の絶縁幅，異方導電性弾性体組成物の厚さに応じてそれぞれ規定されたことを特徴とする。
【００２６】
請求項２記載の発明は、前記導電性粒子の平均粒径Ｄ_ＡＶＥ．において、前記の相対峙する被接続対象の各端子の絶縁幅をｄとすると０．５×ｄ＜Ｄ_ＡＶＥ．＜ｄを満たし、前記導電性粒子の粒径Ｄにおいて、異方導電性弾性体組成物の厚さをｔとすると０．３×ｔ≦Ｄ≦１．２×ｔを満たすことを特徴とする。
【００２７】
請求項３記載の発明は、前記導電性粒子において、１．５ｖｏｌ％〜１３ｖｏｌ％の範囲内で配合されたことを特徴とする。
【００２８】
請求項４記載の発明は、前記絶縁性高分子材料において、スチレン量が２０％〜６０％のスチレン−エチレン共重合体から成ることを特徴とする。
【００２９】
請求項５記載の発明は、前記の異方導電性弾性体組成物の製造方法において、前記の混合物をワニス化（例えば、トルエン等の溶剤によりワニス化）してから被支持体（例えば、ポリエステルフィルム等）表面に塗布（例えば、スクリーン印刷等）した後、乾燥することにより薄膜状に成形し、前記導電性粒子の平均粒径，粒径は、前記の相対峙する被接続対象の各端子の絶縁幅，異方導電性弾性体組成物の厚さに応じてそれぞれ規定（例えば、請求項２に示すように規定）したことを特徴とする。
【００３０】
本発明によれば、相対峙する被接続対象の接続（例えばＬＣＤとＴＣＰとの各回路間の接続，半導体装置のバーンイン試験の装置）において接続信頼性，リペアメント性を確保することができると共に、製造コストを低減することができる。
【００３１】
本発明の異方導電性弾性体組成物の厚さは、その異方導電性弾性体組成物が破断，ピンホール等が起こらないことやハンドリング性を維持できること等を考慮した範囲（例えば、出願時の技術では１０μｍ以上の厚さ）とし、その厚さ，相対峙する被接続対象の各端子間の幅（絶縁幅）等に基づいて導電性粒子の粒径，平均粒径が規定される。
【００３２】
【発明の実施の形態】
以下、本発明の実施の形態における異方導電性組成物を説明する。
【００３３】
本実施の形態では、スチレン−エチレン共重合体等の絶縁性高分子材料に対し、所定粒径（および平均粒径），所定量の導電性粒子（例えば、表面に銀メッキが施された粉体）を添加し混合して分散（均一に分散）させ、その混合物を薄膜状に成形（例えば、ワニス化された混合物をポリエステルフィルム等の被支持体表面に塗布し乾燥して薄膜状に成形）して異方導電性組成物を構成する。前記導電性粒子の平均粒径Ｄ_ＡＶＥ．，粒径Ｄは、目的とする異方導電性組成物の厚さをｔ，絶縁幅（すなわち、相対峙する被接続対象の各電極間の距離、または被検査対象となる半導体装置の各電極間の距離）をｄとした場合、それぞれ下記式を満たすものとする。
【００３４】
０．５×ｄ＜Ｄ_ＡＶＥ．＜ｄ …… （１）
０．３×ｔ≦Ｄ≦１．２×ｔ …… （２）
また、前記導電性粒子の異方導電性組成物中に占める割合は、１．５ｖｏｌ％〜１３ｖｏｌ％の範囲内とする。前記絶縁性高分子材料としてスチレン−エチレン共重合体を用いる場合、そのスチレン量は２０％〜６０％の範囲内とする。
【００３５】
このように構成された異方導電性組成物は、例えば図１の概略図に示すように、薄膜状の異方導電性組成物１０中において比較的（相対峙する被接続対象の接続に用いられていた従来の異方導電性組成物と比較して）大きい粒径の導電性粒子１１が分散して配合され、例えば相対峙する被接続対象１２，１３の接続に用いた場合、その異方導電性組成物１１を加熱することなく単に相対峙する被接続対象１２，１３間に介在（異方導電性組成物を被接続対象１２，１３の端子１２ａ，１３ａ間に挟持される程度に加圧）させて所望の異方性導通を達成することができる。
【００３６】
なお、実際に前記異方導電性組成物を液晶表示体と電気回路との接続に用いる場合、例えば図２に示すように、液晶表示体２１の一部（端子）と電気回路２２の一部（端子）とが異方導電性組成物２３を介して互いに重ね合うように積層され、支持ブロック２４，シーリング材２５等を用いて筐体２６内に収納される。前記異方導電性組成物２３は、前記シーリング材２５の反力によって液晶表示体２１の一部（端子）と電気回路２２の一部（端子）とから加圧される。
【００３７】
従って、本実施の形態の異方導電性組成物は、良好な耐久性，接続信頼性が得られると共に十分なリペアメント性が確保できる。また、従来の異方導電性組成物と比較して簡易な製造工程で構成することができるため、製造コストを低減することがてきる。
【００３８】
さらに、例えば半導体装置のバーンイン試験において（例えば、異方導電性組成物をＩＣソケットのソケット本体の装填部におけるＩＣ検査用基板側開口部に固設した場合）、半導体装置の電極等（導電性針状体を備えた支持ブロックと併用した従来例においては導電性針状体）を異方導電性組成物に没入させて圧縮することなく、単に半導体装置の電極とＩＣ検査用基板の電極端子との間に異方導電性組成物を介在（半導体装置の電極とＩＣ検査用基板の電極端子とを異方導電性組成物に対して接触する程度に圧接（後述する実施例では１．６７×１０^−４ＭＰａ〜２．０４×１０^−４ＭＰａで圧接））させて所望の試験（異方性導通）を行うことができるため、その試験による半導体装置のレジスト層等の損傷，半田紛の発生等や異方導電性組成物の導電性粒子の離脱，シリコーンオイルの浸出等が防止され、その異方導電性組成物の耐久性，接続信頼性が維持されると共に十分なリペアメント性が確保される。
【００３９】
［実施例］
次に、本実施の形態における異方導電性組成物において種々の試料を作製し、それら各試料の接続信頼性，リペアメント性を調べた。
【００４０】
まず、水２００重量部に対し、メチルメタアクリレートを１００重量部，エチレングリコールジメタクリレートを４重量部，過酸化ベンゾイルを０．５重量部の割合で添加し、所定の条件（温度，時間等）で撹拌混合して懸濁重合することにより、所定の平均粒径の核（温度１００℃，１０００ｒｐｍの回転下で２時間撹拌混合して懸濁重合した場合には平均粒径１５μｍの核）を含んだ懸濁液を得た。次に、前記の懸濁液に対し、その懸濁液を撹拌しながらエチルメタクリレートを５０重量部，過酸化ベンゾイルを０．５重量部，エチレングリコールジメタクリレートを２重量部の割合で添加し、所定の条件（温度，時間等）で撹拌混合して重合することにより球状で表面に殻が形成された粉体を得、その粉体を冷却，水洗，乾燥することにより所定の平均粒径の架橋アクリル樹脂粒子（温度９０℃，１０００ｒｐｍの回転下で２時間撹拌混合して重合することにより殻が形成された粉体を得た場合は平均粒径３０μｍの架橋アクリル樹脂粒子）を得た。その後、前記アクリル樹脂の表面（球面）に対し、無電解メッキによって厚さ０．１μｍの銀メッキ層を形成することにより、平均粒径７０μｍ〜２０μｍの導電性粒子Ｐ１〜Ｐ６を得た。なお、前記導電性粒子の平均粒径は、前記架橋アクリル樹脂の各撹拌混合の条件を種々設定することにより調整が可能となる。
【００４１】
また、溶剤（トルエン）１００グラムに対しスチレン−エチレン共重合体（スチレンエチレンブタジエンスチレン共重合体；本実施例ではクレイトンジャパン製のクレイトンＤ１１１８）を５０グラム添加して、温度６０℃の雰囲気下（例えば、オイルバス中）で２時間撹拌して溶解することにより絶縁性の高分子溶液を得た。
【００４２】
そして、前記高分子溶液に対して前記導電性粒子Ｐ１〜Ｐ６の何れかを所定量添加し、２時間撹拌して混合し、その混合液を例えばポリエステルフィルム上に対し薄膜状に塗布し乾燥することにより、厚さ３０μｍの異方導電性組成物の試料Ｓ１〜Ｓ６を得た。なお、前記混合液を薄膜状に塗布する場合、コート方式（リバースコータ法，グラビアコータ法）やスプレー方式を適用しても良いが、スクリーン印刷（例えば、ミノグループ製のＭＩＮＯＭＡＴのＹ−ＳＥＲＩＥＳを用いたスクリーン印刷）方式が好ましい。下記表１は、前記試料Ｓ１〜Ｓ６における各成分の配合量等を示すものである。
【００４３】
【表１】

【００４４】
次に、前記の各試料Ｓ１〜Ｓ６において、図３，図４に示す方法（詳細は後述する）により接続信頼性（導通性，非リーク性），リペアメント性を調べた。
【００４５】
図３Ａ（平面図），Ｂ（側面図）において、符号３０ａ，３０ｂはそれぞれ表面に短冊状のアルミ電極３１ａ，３１ｂ（図３Ａでは破線部）が複数個１００μｍピッチで蒸着形成された平板状のアルミ蒸着基板（市販のアルミ蒸着基板（電極ピッチ１００μｍ，電極幅５０μｍ，絶縁幅５０μｍ））を示すものであり、それらアルミ電極３１ａの一部とアルミ電極３１ｂの一部とが異方導電性組成物の試料３２（試料Ｓ１〜Ｓ６）を介して互いに重ね合うように積層（１．６７×１０^−４ＭＰａ〜２．０４×１０^−４ＭＰａで圧接して積層）させる。そして、図示するように、前記の重なり合ったアルミ電極３１ａとアルミ電極３１ｂとの間の抵抗値を計測器３３で測定することにより、試料３２の導通性を調べることができる。
【００４６】
また、図４Ａ（平面図），Ｂ（側面図）に示すように（図３と同様なものは詳細な説明を省略）、アルミ電極３１ａと、該アルミ電極３１ａに隣接した電極と重なり合ったアルミ電極３１ｂと、の間における抵抗値を測定することにより、試料３２の非リーク性を調べることができる。さらに、図４に示す方法でアルミ電極３１ａと、該アルミ電極３１ａに隣接した電極と重なり合ったアルミ電極３１ｂと、の間における抵抗値を測定した後に試料３２をアルミ蒸着基板３０ａ，３０ｂから剥離する作業を１工程とし、この工程を複数回（本実施例では５回）繰り返し行うことにより、試料３２のリペアメント性を調べることができる。
【００４７】
前記の各方法により調べた各試料Ｓ１〜Ｓ６の導通性，非リーク性，リペアメント性の結果を下記表２に示した。なお、下記表２において、導通性の項目での記号「○」は抵抗値が１０Ω未満、記号「△」は抵抗値が１０Ω以上で１ＭΩ未満、記号「×」は抵抗値が１ＭΩ以上の場合を示すものとする。また、非リーク性の項目での記号「○」は抵抗値が１ＭΩ以上、記号「△」は抵抗値が１０Ω以上で１ＭΩ未満、記号「×」は抵抗値が１０Ω未満の場合を示すものとする。リペアメント性の項目での記号「○」は抵抗値が１０Ω未満でアルミ電極３１ａ，３１ｂに試料３２の一部が付着して残存、記号「△」は抵抗値が１０Ω以上で１ＭΩ未満、記号「×」は抵抗値が１ＭΩ以上でアルミ電極３１ａ，３１ｂに対し試料３２の付着による残存が無い場合を示すものとする。
【００４８】
【表２】

【００４９】
前記表２に示すように、導電性粒子の平均粒径が５０μｍ以上または２０μｍの試料Ｓ１〜Ｓ３，Ｓ６を用いた場合、リペアメント性は良好であるが、導通性または非リーク性が低くなってしまった。一方、導電性粒子の平均粒径が４０μｍ〜３０μｍ以上の試料Ｓ４，Ｓ５を用いた場合、導通性，非リーク性，リペアメント性の全て良好であった。なお、導電性粒子の平均粒径が前記（１）式を満たす異方導電性組成物であれば、導通性，非リーク性，リペアメント性の全てが良好になることを確認した。
【００５０】
次に、前記試料Ｓ５において導電性粒子Ｐ５の配合量を下記表３に示すように０．３重量部〜６重量部（すなわち、０．８ｖｏｌ％〜１３．３ｖｏｌ％）の範囲内で種々設定して異方導電性組成物の試料Ｓ７〜Ｓ１１を作製し、前記試料Ｓ１〜Ｓ６と同様の方法により導通性，非リーク性，リペアメント性を調べ、その結果を下記表４に示した。
【００５１】
【表３】

【００５２】
【表４】

【００５３】
前記表４に示すように、導電性粒子Ｐ５の配合量が０．８ｖｏｌ％，１３．３ｖｏｌ％の試料Ｓ７，Ｓ１１を用いた場合、リペアメント性は良好であるが、導通性または非リーク性が低くなってしまった。一方、導電性粒子Ｐ５の配合量が１．５ｖｏｌ％〜１０．３ｖｏｌ％の試料Ｓ８〜Ｓ１０を用いた場合、導通性，非リーク性，リペアメント性の全てが良好であった。なお、導電性粒子Ｐ５の配合量が１．５ｖｏｌ％〜１３ｖｏｌ％の範囲内の異方導電性組成物であれば、導通性，非リーク性，リペアメント性の全てが良好になることを確認した。
【００５４】
次に、前記試料Ｓ９において導電性粒子Ｐ５の粒径を下記表５に示すように６μｍ〜４５μｍ（すなわち、異方導電性組成物の厚さ（３０μｍ）に対する粒径の倍率が０．２倍〜１．５倍）の範囲内で種々設定して異方導電性組成物の試料Ｓ１２〜Ｓ１８を作製し、前記試料Ｓ１〜Ｓ６と同様の方法により導通性，非リーク性，リペアメント性を調べ、その結果を下記表６に示した。
【００５５】
【表５】

【００５６】
【表６】

【００５７】
前記表６に示すように、異方導電性組成物の厚さに対する導電性粒子Ｐ５の粒径の倍率が０．２倍，１．５倍の試料Ｓ１２，Ｓ１８を用いた場合、リペアメント性は良好であるが、導通性または非リーク性が低くなってしまった。一方、異方導電性組成物の厚さに対する導電性粒子Ｐ５の粒径の倍率が０．３倍〜１．２倍の試料Ｓ１３〜Ｓ１７を用いた場合、導通性，非リーク性，リペアメント性の全てが良好であった。なお、異方導電性組成物の厚さに対する導電性粒子Ｐ５の粒径の倍率が前記（２）式を満たす異方導電性組成物であれば、導通性，非リーク性，リペアメント性の全てが良好になることを確認した。
【００５８】
次に、前記試料Ｓ９において下記表７に示すように種々のスチレン量のスチレン−エチレン共重合体を用いて異方導電性組成物の試料Ｓ１９〜Ｓ２３を作製し、前記試料Ｓ１〜Ｓ６と同様の方法により導通性，非リーク性，リペアメント性を調べ、その結果を下記表８に示した。
【００５９】
【表７】

【００６０】
【表８】

【００６１】
前記表８に示すように、スチレン−エチレン共重合体のスチレン量が１８％または６７％の試料Ｓ１９，Ｓ２３を用いた場合、非リーク性は良好であるが、導通性またはリペアメント性が低くなってしまった。一方、スチレン−エチレン共重合体のスチレン量が２４％〜５２％の範囲内の試料Ｓ２０〜Ｓ２２を用いた場合、導通性，非リーク性，リペアメント性の全てが良好であった。なお、スチレン−エチレン共重合体のスチレン量が２０％〜６０％の範囲内の異方導電性組成物であれば、導通性，非リーク性，リペアメント性の全てが良好になることを確認した。
【００６２】
次に、前記試料Ｓ５において、下記表９に示すように導電性粒子Ｐ５の替わりに真鍮紛（平均粒径３０μｍ）またはニカビーズ（平均粒径３０μｍ）を用いて異方導電性組成物の試料Ｓ２４，Ｓ２５を作製し、前記試料Ｓ１〜Ｓ６と同様の方法により導通性，非リーク性，リペアメント性を調べ、その結果を下記表１０に示した。
【００６３】
【表９】

【００６４】
【表１０】

【００６５】
前記表１０に示すように、導電性粒子として真鍮紛またはニカビーズを用いた試料Ｓ２４，Ｓ２５は、試料Ｓ５と同様に導通性，非リーク性，リペアメント性の全てが良好であった。なお、例えば導電性粒子Ｐ５において銀の替わりに種々の金属（例えば、導電性の高いニッケル，金，銅等の金属）を被覆し前記（１），（２）式を満たす導電性粒子が用いられた異方導電性組成物であれば、導通性，非リーク性，リペアメント性の全てが良好になることは明らかである。
【００６６】
以上、本発明において、記載された具体例に対してのみ詳細に説明したが、本発明の技術思想の範囲で多彩な変形および修正が可能であることは、当業者にとって明白なことであり、このような変形および修正が特許請求の範囲に属することは当然のことである。
【００６７】
例えば、本実施例では、絶縁性高分子材料，導電性粒子，溶剤（トルエン）がそれぞれ所定の条件で配合された混合液を用い、その混合液を薄膜状に塗布し乾燥して異方導電性組成物を作製したが、前記混合液には絶縁性高分子材料，導電性粒子，溶剤だけでなく、異方導電性組成物の使用目的に応じて種々の添加剤を配合しても良い。
【００６８】
また、本実施例では、表面に金属が被覆された粉体を導電性粒子として用いたが、例えば粉体全体が金属から成るものであっても、前記（１），（２）式を満たす導電性粒子であれば異方導電性組成物において導通性，非リーク性，リペアメント性の全てが良好になることは明らかである。
【００６９】
【発明の効果】
以上示したような本発明の異方導電性組成物においては、相対峙する被接続対象の接続に用いられていた従来の異方導電性組成物と比較して簡易な製造工程で作製することができる。
【００７０】
また、異方導電性組成物を加熱することなく単に相対峙する被接続対象間に介在（異方導電性組成物を相対峙する被接続対象の両端子間に挟持される程度に加圧）させて所望の異方性導通を達成することができる。
【００７１】
さらに、例えば半導体装置のバーンイン試験の装置に用いた場合、半導体装置の電極等を異方導電性組成物に没入させて圧縮することなく、単に半導体装置の電極とＩＣ検査用基板の電極端子との間に異方導電性組成物を介在（半導体装置の電極とＩＣ検査用基板の電極端子とを異方導電性組成物に対して接触する程度に圧接）させて所望の試験（異方性導通）を行うことができる。
【００７２】
ゆえに、本発明の異方導電性組成物によれば、良好な耐久性，接続信頼性が得られると共に十分なリペアメント性が確保でき、製造コストを低減することが可能となる。
【図面の簡単な説明】
【図１】本実施の形態における異方導電性弾性体組成物の概略説明図。
【図２】本実施の形態における異方導電性弾性体組成物の使用例を示す概略説明図。
【図３】本実施例の導通性の測定方法を示す概略説明図。
【図４】本実施例の非リーク性，リペアメント性の測定方法を示す概略説明図。
【符号の説明】
１０，２３…異方導電性弾性体組成物
１１…導電性粒子
１２，１３…被接続対象
３２…試料[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is an anisotropic conductive elastic body composition for interposing between a desired terminal of one circuit and a desired terminal of the other circuit, which is interposed between opposing circuits, and a method for producing the same. For example, electrical connection between various fine circuits such as connection between LCD (liquid crystal display) or PDP (plasma display) and TCP (tape carrier package), connection between TCP and PCB (printed circuit board), and semiconductor device. The present invention relates to an anisotropic conductive elastic material composition used for a burn-in test device.
[0002]
[Prior art]
Conventionally, the connection between the LCD or PDP and the TCP, the connection between the TCP and the PCB, the FPC (flexible printed circuit board) or TAB (tape auto bonding) and the terminal on the glass substrate of the liquid crystal panel (for example, ITO (tin indium oxide)) ), An anisotropic conductive elastic composition (hereinafter referred to as an anisotropic conductive composition) is used. Anisotropic conduction can be ensured by interposing and heating and pressurizing (by bonding each circuit) between connection objects (for example, between circuits of LCD and TCP). That is, electrical insulation is maintained between terminals adjacent to each other in the surface direction (hereinafter, referred to as adjacent terminals) (to prevent crosstalk), and conduction is established between the opposing terminals to be connected. Each terminal of one circuit and each terminal of the other circuit can be electrically connected to each other.
[0003]
This anisotropic conductive composition has been used because the circuit to be connected (circuits such as LCD) has low heat resistance, and the miniaturization of the circuit causes an electrical short between adjacent terminals. This is because the conventional connection method such as simple soldering cannot be applied due to the danger or the like.
[0004]
Conventional anisotropic conductive compositions include a resin having adhesive properties (for example, an epoxy resin and a phenolic resin) and a conductive substance (for example, conductive particles) dispersed in an adhesive mainly containing a curing agent. What is made by making it (hereinafter, referred to as an adhesive composition) is widely known, and is mainly classified into a thermoplastic type and a thermosetting type.
[0005]
In addition, since the thermoplastic adhesive composition adheres opposing circuits by a fusion welding method, the work required for the bonding process is performed in a relatively low-temperature atmosphere (compared to a thermosetting adhesive) and in a short time. Although it can be performed in a short time, the moisture resistance, chemical resistance, and connection reliability (accuracy of anisotropic conduction) of the resin used are low, and it is difficult to obtain sufficient durability for a long-term environmental test, for example. .
[0006]
On the other hand, as for thermosetting adhesive compositions, those using an epoxy resin are generally widely known, and have better moisture resistance, chemical resistance and connection reliability than those of thermoplastic type. Sufficient curability is obtained, for example, a latent curing agent (for example, BF ₃ The use of amine complex, dicyandiamide, organic acid hydrazide, imidazole compound, etc.) can improve the storage stability, but as the storage stability improves, the curability decreases (the curing operation takes a long time or in a high-temperature atmosphere). On the contrary, there is a problem that when the curability is improved, the storage stability is reduced.
[0007]
Further, in the above-mentioned adhesive composition, for example, when the objects to be connected facing each other in the connecting step are not bonded at a predetermined position, the objects to be bonded (and the adhesive composition) are not damaged or damaged. It was difficult to peel and bond or join again (hereinafter referred to as repairability). For this reason, development of an anisotropic conductive composition having sufficient durability (mechanical strength, moisture resistance, chemical resistance, curability, etc.), connection reliability, etc., and good repairability has been demanded. Was.
[0008]
In recent years, Japanese Patent Application Laid-Open No. 9-259635 discloses an anisotropic conductive composition comprising two types of films (first and second films described later) as an anisotropic conductive composition in consideration of the repairability. Have been. This anisotropic conductive composition is obtained by first adding a predetermined amount of conductive particles having a predetermined particle size to a paint obtained by dissolving an epoxy resin in toluene, and mixing the resulting mixture with a first film (e.g., positioned on the ITO electrode terminal side). Film). A second film (for example, a film positioned on the TBO side) is obtained by adding a predetermined amount of conductive particles having a predetermined particle size to a paint obtained by dissolving a curing agent, a curing accelerator, and a thermoplastic resin in toluene. ) Is formed, and the second film and the first film are laminated to obtain an anisotropic conductive composition (hereinafter, referred to as a laminated structure composition).
[0009]
The laminated structure composition configured as described above is interposed between, for example, an ITO electrode terminal and a TBO terminal on a glass substrate (at least the second film is interposed so as to be located on the ITO electrode terminal side). The positions of the conductive particles are fixed between the terminals of each film by heat-pressing the gaps between the terminals, and by melting and mixing in the first film and the second film to cause a hardening reaction in the first film and the second film. The connection reliability can be secured. In addition, during the thermocompression bonding, the first film and the second film are not completely melted and mixed, and a large amount of a solvent-soluble thermoplastic resin component occupies the vicinity of the ITO electrode interface in the laminated structure composition. It is said that the laminated structure composition can be easily peeled off and has high repairability.
[0010]
[Patent Document 1]
JP-A-9-259635 (paragraphs [0009] to [0015]).
[0011]
Japanese Patent Application Laid-Open No. 2002-180012 discloses an anisotropic conductive composition containing an epoxy coupling agent and an allyl-modified cyanurate. By improving the coupling effect (chemical bonding), connection reliability and repairability are improved. It can be secured.
[0012]
[Patent Document 2]
JP-A-2002-180012 (paragraphs [0015], [0034] to [0037]).
[0013]
The anisotropic conductive composition may be, for example, a device for a burn-in test of a semiconductor device (a connection target is an electrode of a semiconductor device and an IC, in addition to the one used for connection between the LCD and TCP circuits as described above). What is used for the electrode terminal of the board | substrate for a test) is known. In a conventional burn-in test, an IC socket is used to connect electrodes and leads of a semiconductor device to electrode terminals of an IC inspection board. The IC socket includes, for example, a loading portion in which the semiconductor device can be loaded and a loading portion in which the semiconductor device is loaded. An electrode terminal which is fixedly connected to the main body, a lead and a pin which is fixedly connected to the side or bottom of the socket body via a lead wire, and a lid member which is attached to a front opening of the loading portion by a hinge or the like. Was composed of
[0014]
However, in the case of the conventional IC socket, the number of parts is large because electrode terminals, leads, pins and the like are required, and the assembling process is complicated. Further, the IC socket needs to be connected to the IC inspection substrate by soldering or the like (that is, the number of inspection steps is increased). Further, in the case of an IC socket provided with the above-mentioned pins, it is necessary to form a through hole for a pin in the IC inspection board, and there is a problem that the design of the IC inspection board becomes complicated. Was.
[0015]
On the other hand, as a device using an anisotropic conductive composition, for example, in Japanese Patent Application Laid-Open No. 2001-273960, a thin film of an elastomer is filled so as to penetrate a wire (such as gold) (at a position corresponding to an electrode of a semiconductor device). An IC socket is disclosed in which an anisotropic conductive composition (elastomer connector; hereinafter, referred to as a wire composition) formed by filling is fixed to an IC inspection board side opening in a loading portion of a socket body. ing. Each electrode and each lead of the semiconductor device loaded in the loading portion of the IC socket are electrically connected to the electrode terminals of the IC inspection substrate via the wire composition, and between each adjacent electrode of the semiconductor device and each lead. Insulation can be maintained between them.
[0016]
[Patent Document 3]
JP 2001-273960 A (paragraphs [0005] to [0013]).
[0017]
Also, Japanese Patent Application Laid-Open No. 7-174788 discloses a conductive needle which is provided so as to be able to reciprocate in the axial direction of a support hole penetrating in the thickness direction of a support block and has a tip portion which comes into contact with an electrode of a semiconductor device. An anisotropic conductive composition comprising conductive material dispersed in a rubber matrix and being interposed between the substrate for IC inspection and the support block (the rear end side of the conductive needle). Are disclosed. When the conductive needle of this device is brought into contact with the electrode of the semiconductor device to be inspected, the rear end of the conductive needle is deformed against the repulsive force of the anisotropic conductive composition. An electrode of the semiconductor device and a substrate for IC inspection through conductive particles (a plurality of conductive particles) in the anisotropic conductive composition in a region compressed by the immersion in the anisotropic conductive composition; Is electrically connected to the electrode terminals.
[0018]
[Patent Document 4]
JP-A-7-174788 (paragraphs [0008] and [0009], FIGS. 1 to 4).
[0019]
[Problems to be solved by the invention]
However, as described above, the anisotropic conductive composition used for the connection of the objects to be connected (for example, the connection between the circuits of the LCD and the TCP and the apparatus for the burn-in test of the semiconductor device) is as follows. There was a problem as shown.
[0020]
In the case of the above-mentioned laminated structure composition, it is necessary to laminate two kinds of films, so that the production cost is increased due to an increase in the number of production steps, and the first film of the laminated structure composition is heated, for example, on the TAB surface. Since the curing reaction occurs through the step of pressing (and melting and mixing), the first film after the curing reaction reflects the shape of the TAB surface. That is, although it is easy to peel off the laminated structure composition from the ITO electrode terminal, a sufficient repairability could not be obtained since the laminated structure composition could not maintain its shape before use.
[0021]
In an anisotropic conductive composition containing an epoxy coupling agent and an allyl-modified cyanurate, connection reliability can be improved by strengthening the chemical bond, but this anisotropic conductive composition is used by bonding by heating and pressing. Therefore, sufficient repairability was not obtained (Japanese Patent Application Laid-Open No. 2002-180012 does not disclose any technical measures relating to the repairability).
[0022]
In the case of a wire composition used in an apparatus for a burn-in test of a semiconductor device, the number of manufacturing steps (a step of sandwiching a wire between uncured rubber sheets, a step of press-curing, a step of cutting the cured product, and a position control of the cut product by a plate Process, molding process using an insulating elastomer), the number of parts increases the manufacturing cost, and the wires (tips of the wires) damage the resist layer of a semiconductor device, for example. There was a fear that it would. In addition, there is a problem that solder powder is apt to be generated due to contact between the wire and an electrode of the semiconductor device, and if the solder powder adheres to the wire composition, a connection failure or the like occurs. Furthermore, silicone oil may leach out of the wire composition, and if the silicone oil adheres to the semiconductor device, the solder wettability during solder mounting after the burn-in test is reduced.
[0023]
In the anisotropic conductive composition used in combination with the support block having the conductive needles, when the amount of compression by the conductive needles is large (the conductive needles are contained in the anisotropic conductive composition. When the conductive needles are immersed and all of the conductive particles in the immersed area come into contact with each other), anisotropic conduction is achieved. Therefore, when the burn-in test is repeatedly performed, the durability of the anisotropic conductive composition may be reduced, and the conductive particles may be detached from the anisotropic conductive composition and short-circuited. When the distance between the electrodes of the semiconductor device is short due to miniaturization of the circuit (that is, when the distance between the conductive needles is short), the entire surface of the support block side of the anisotropic conductive composition is compressed. And crosstalk occurs.
[0024]
SUMMARY OF THE INVENTION The present invention has been made based on the above-mentioned problem, and has a connection reliability and a repair in connection of opposing connection targets (for example, connection between circuits of LCD and TCP, a device for a burn-in test of a semiconductor device). An object of the present invention is to provide an anisotropic conductive composition which secures the properties and reduces the production cost, and a method for producing the same.
[0025]
[Means for Solving the Problems]
The present invention is intended to solve the above-mentioned problems, and the invention according to claim 1 includes at least an insulating polymer material and conductive particles (for example, a powder having a surface coated with a metal having good conductivity). In an anisotropic conductive elastic composition (for example, a thin film-shaped anisotropic conductive elastic composition) which is composed of a mixture containing and is used for connection of opposed objects to be connected, the average particle size of the conductive particles The particle size is defined in accordance with the insulation width of each of the opposed terminals to be connected and the thickness of the anisotropic conductive elastic composition.
[0026]
The invention according to claim 2 is a method according to claim 2, wherein the conductive particles have an average particle diameter D. _AVE. In the above, if the insulation width of each of the opposed terminals to be connected is d, 0.5 × d <D _AVE. <D, and the particle diameter D of the conductive particles satisfies 0.3 × t ≦ D ≦ 1.2 × t, where t is the thickness of the anisotropic conductive elastic body composition. .
[0027]
The invention according to claim 3 is characterized in that the conductive particles are blended in a range of 1.5 vol% to 13 vol%.
[0028]
The invention according to claim 4 is characterized in that the insulating polymer material is made of a styrene-ethylene copolymer having a styrene content of 20% to 60%.
[0029]
According to a fifth aspect of the present invention, in the method for producing an anisotropically conductive elastic material composition, the mixture is varnished (for example, varnished with a solvent such as toluene), and then the supported material (for example, polyester). After coating (for example, screen printing, etc.) on the surface of the film, and then drying to form a thin film, the average particle diameter and the particle diameter of the conductive particles are determined by the respective terminals of the opposing connection target. (E.g., as defined in claim 2) according to the insulation width and the thickness of the anisotropically conductive elastic composition.
[0030]
ADVANTAGE OF THE INVENTION According to this invention, connection reliability and repairability can be ensured in the connection (for example, the connection between each circuit of LCD and TCP, the apparatus of a burn-in test of a semiconductor device) of the connection object facing each other. In addition, manufacturing costs can be reduced.
[0031]
The thickness of the anisotropically conductive elastic body composition of the present invention is within a range (for example, in the case of the application) in consideration of the fact that the anisotropically conductive elastic body composition does not cause breakage, pinholes, etc., and can maintain handling properties. The thickness of the conductive particles is set to 10 μm or more according to the conventional technology, and the particle size and the average particle size of the conductive particles are defined based on the thickness, the width (insulation width) between the opposing terminals to be connected, and the like. .
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the anisotropic conductive composition according to the embodiment of the present invention will be described.
[0033]
In this embodiment, a predetermined particle size (and an average particle size) and a predetermined amount of conductive particles (for example, powder having a silver-plated surface) are applied to an insulating polymer material such as a styrene-ethylene copolymer. Is added and mixed and dispersed (uniformly dispersed), and the mixture is formed into a thin film (for example, a varnished mixture is applied to the surface of a support such as a polyester film and dried to form a thin film) ) To form an anisotropic conductive composition. Average particle size D of the conductive particles _AVE. , The particle size D, the thickness of the target anisotropic conductive composition is t, the insulation width (that is, the distance between the opposing electrodes to be connected, or the electrodes of the semiconductor device to be inspected). When the distance between them is d, it is assumed that each of the following expressions is satisfied.
[0034]
0.5 × d <D _AVE. <D ... (1)
0.3 × t ≦ D ≦ 1.2 × t (2)
The ratio of the conductive particles in the anisotropic conductive composition is in the range of 1.5 vol% to 13 vol%. When a styrene-ethylene copolymer is used as the insulating polymer material, the amount of styrene is in the range of 20% to 60%.
[0035]
The anisotropic conductive composition thus configured is used in a thin film-shaped anisotropic conductive composition 10 for relatively (to be used for connection of objects to be connected, as shown in the schematic diagram of FIG. 1, for example). When the conductive particles 11 having a large particle size are dispersed and compounded (compared with a conventional anisotropic conductive composition which has been used, for example, when they are used for connecting

opposed objects

12 and 13 facing each other), Without heating the anisotropically conductive composition 11, it is interposed between the

connected objects

12 and 13 which face each other (to the extent that the anisotropically conductive composition is sandwiched between the terminals 12 a and 13 a of the connected objects 12 and 13). Pressure) to achieve the desired anisotropic conduction.
[0036]
When the anisotropic conductive composition is actually used for connection between a liquid crystal display and an electric circuit, for example, as shown in FIG. 2, a part (terminal) of the liquid crystal display 21 and a part of the electric circuit 22 are used. (Terminals) are stacked so as to overlap each other with the anisotropic conductive composition 23 interposed therebetween, and are housed in the housing 26 using the support block 24, the sealing material 25, and the like. The anisotropic conductive composition 23 is pressed from a part (terminal) of the liquid crystal display 21 and a part (terminal) of the electric circuit 22 by the reaction force of the sealing material 25.
[0037]
Therefore, the anisotropic conductive composition of the present embodiment can obtain good durability and connection reliability and can secure sufficient repairability. In addition, since it can be constituted by a simple manufacturing process as compared with the conventional anisotropic conductive composition, the manufacturing cost can be reduced.
[0038]
Further, for example, in a burn-in test of a semiconductor device (for example, when an anisotropic conductive composition is fixed to an IC inspection substrate side opening in a mounting portion of a socket body of an IC socket), an electrode of the semiconductor device (conductive In a conventional example in which a support block provided with a needle-shaped body is used in combination, the conductive needle-shaped body is immersed in the anisotropic conductive composition and compressed, and the electrode of the semiconductor device and the electrode terminal of the IC inspection substrate are simply used. (An electrode of a semiconductor device and an electrode terminal of an IC inspection substrate are pressed into contact with the anisotropic conductive composition to the extent that the anisotropic conductive composition is brought into contact with the anisotropic conductive composition (1.67 in Examples described later). × 10 ^-4 MPa ~ 2.04 × 10 ^-4 (Pressure welding with MPa)) to perform a desired test (anisotropic conduction), which results in damage to the resist layer of the semiconductor device, generation of solder powder, etc., and the conductivity of the anisotropic conductive composition. Separation of particles, leaching of silicone oil, and the like are prevented, and the durability and connection reliability of the anisotropic conductive composition are maintained, and sufficient repairability is secured.
[0039]
[Example]
Next, various samples were prepared from the anisotropic conductive composition according to the present embodiment, and the connection reliability and repairability of each sample were examined.
[0040]
First, 100 parts by weight of methyl methacrylate, 4 parts by weight of ethylene glycol dimethacrylate, and 0.5 parts by weight of benzoyl peroxide are added to 200 parts by weight of water under predetermined conditions (temperature, time, etc.). The suspension having a predetermined average particle size (a core having an average particle size of 15 μm when the suspension polymerization is carried out by stirring and mixing at a temperature of 100 ° C. under a rotation of 1000 rpm for 2 hours) is carried out. A suspension containing was obtained. Next, 50 parts by weight of ethyl methacrylate, 0.5 parts by weight of benzoyl peroxide, and 2 parts by weight of ethylene glycol dimethacrylate were added to the suspension while stirring the suspension. By stirring and mixing under predetermined conditions (temperature, time, etc.) and polymerizing, a spherical powder having a shell formed on the surface is obtained, and the powder is cooled, washed with water and dried to obtain a powder having a predetermined average particle size. Cross-linked acrylic resin particles (crosslinked acrylic resin particles having an average particle diameter of 30 μm when a powder having a shell formed by polymerization by stirring and mixing at a temperature of 90 ° C. and rotating at 1000 rpm for 2 hours) were obtained. Thereafter, a silver plating layer having a thickness of 0.1 μm was formed on the surface (spherical surface) of the acrylic resin by electroless plating to obtain conductive particles P1 to P6 having an average particle size of 70 μm to 20 μm. The average particle size of the conductive particles can be adjusted by setting various stirring and mixing conditions of the crosslinked acrylic resin.
[0041]
Further, 50 g of a styrene-ethylene copolymer (styrene-ethylene-butadiene-styrene copolymer; Clayton D1118 manufactured by Clayton Japan in this example) was added to 100 g of the solvent (toluene), and the mixture was heated under an atmosphere at a temperature of 60 ° C. ( For example, the mixture was stirred for 2 hours in an oil bath and dissolved to obtain an insulating polymer solution.
[0042]
Then, a predetermined amount of any of the conductive particles P1 to P6 is added to the polymer solution, and the mixture is stirred for 2 hours and mixed, and the mixed solution is applied on a polyester film in the form of a thin film and dried. Thereby, samples S1 to S6 of the anisotropic conductive composition having a thickness of 30 μm were obtained. When the mixture is applied in the form of a thin film, a coating method (reverse coater method, gravure coater method) or a spray method may be applied, but screen printing (for example, Y-SERIES of MINOMAT manufactured by Mino Group) may be used. Screen printing method) is preferable. Table 1 below shows the amounts of the components in the samples S1 to S6, and the like.
[0043]
[Table 1]

[0044]
Next, in each of the samples S1 to S6, connection reliability (conductivity, non-leak property) and repairability were examined by the method shown in FIGS. 3 and 4 (details will be described later).
[0045]
In FIGS. 3A (plan view) and B (side view),

reference numerals

30a and 30b denote flat plate-like electrodes on which a plurality of strip-shaped

aluminum electrodes

31a and 31b (broken lines in FIG. 3A) are formed at a pitch of 100 μm. 1 shows an aluminum-deposited substrate (a commercially available aluminum-deposited substrate (electrode pitch: 100 μm, electrode width: 50 μm, insulation width: 50 μm)), in which a part of the aluminum electrode 31 a and a part of the aluminum electrode 31 b are anisotropically conductive. (1.67 × 10 6) so as to overlap with each other via the sample 32 (samples S1 to S6). ^-4 MPa ~ 2.04 × 10 ^-4 The layers are pressed together at a pressure of MPa. Then, as shown in the figure, the conductivity of the sample 32 can be checked by measuring the resistance value between the overlapped aluminum electrode 31a and the aluminum electrode 31b with the measuring instrument 33.
[0046]
As shown in FIGS. 4A (plan view) and B (side view) (detailed description is omitted for components similar to FIG. 3), the aluminum electrode 31a and the aluminum overlapping the electrode adjacent to the aluminum electrode 31a are formed. By measuring the resistance value between the electrode 31b and the electrode 31b, the non-leak property of the sample 32 can be checked. Further, after measuring the resistance value between the aluminum electrode 31a and the aluminum electrode 31b overlapping the electrode adjacent to the aluminum electrode 31a by the method shown in FIG. 4, the sample 32 is peeled off from the

aluminum deposition substrates

30a and 30b. By setting the operation as one step and repeating this step a plurality of times (five times in this embodiment), the repairability of the sample 32 can be checked.
[0047]
Table 2 below shows the results of the conductivity, non-leakage, and repairability of each of the samples S1 to S6 examined by the above methods. In Table 2, the symbol “○” in the item of conductivity indicates that the resistance value is less than 10Ω, the symbol “△” indicates that the resistance value is 10Ω or more and less than 1MΩ, and the symbol “x” indicates that the resistance value is 1MΩ or more. Shall be shown. The symbol “記号” in the non-leakage item indicates that the resistance value is 1 MΩ or more, the symbol “△” indicates that the resistance value is 10 Ω or more and less than 1 MΩ, and the symbol “x” indicates that the resistance value is less than 10 Ω. I do. The symbol “○” in the item of the repairability indicates that the resistance value is less than 10Ω and a part of the sample 32 adheres to the

aluminum electrodes

31a and 31b and remains. “X” indicates a case where the resistance value is 1 MΩ or more and there is no residue due to the adhesion of the sample 32 to the

aluminum electrodes

31 a and 31 b.
[0048]
[Table 2]

[0049]
As shown in Table 2, when the samples S1 to S3 and S6 having an average particle diameter of the conductive particles of 50 μm or more or 20 μm are used, the repairability is good, but the conductivity or the non-leakage is low. I have. On the other hand, when the samples S4 and S5 in which the average particle size of the conductive particles was 40 μm to 30 μm or more were used, the conductivity, the non-leakage property, and the repairability were all good. In addition, it was confirmed that when the anisotropic conductive composition had the average particle diameter of the conductive particles satisfying the above-mentioned formula (1), the conductivity, the non-leak property, and the repairability were all good.
[0050]
Next, in the sample S5, the compounding amount of the conductive particles P5 is variously set within a range of 0.3 to 6 parts by weight (that is, 0.8 to 13.3 vol%) as shown in Table 3 below. Then, samples S7 to S11 of the anisotropic conductive composition were prepared, and the conductivity, non-leakage property, and repairability were examined in the same manner as in the above samples S1 to S6. The results are shown in Table 4 below.
[0051]
[Table 3]

[0052]
[Table 4]

[0053]
As shown in Table 4, when the samples S7 and S11 in which the amount of the conductive particles P5 was 0.8 vol% and 13.3 vol% were used, the repairability was good, but the conductivity or the non-leakage property was high. Has become low. On the other hand, when Samples S8 to S10 in which the blending amount of the conductive particles P5 was 1.5 vol% to 10.3 vol% were used, all of the conductivity, the non-leakage property, and the repairability were good. In addition, if the compounding amount of the conductive particles P5 is in the range of 1.5 vol% to 13 vol%, it is confirmed that all of the conductivity, the non-leak property, and the repairability are good. did.
[0054]
Next, in the sample S9, as shown in Table 5 below, the particle size of the conductive particles P5 was 6 to 45 μm (that is, the ratio of the particle size to the thickness (30 μm) of the anisotropic conductive composition was 0.2 times). Samples S12 to S18 of the anisotropic conductive composition were prepared by various settings within the range of (１．５1.5 times), and the conductivity, non-leakage property, and repairability were measured in the same manner as in Samples S1 to S6. Investigation and the results are shown in Table 6 below.
[0055]
[Table 5]

[0056]
[Table 6]

[0057]
As shown in Table 6, when samples S12 and S18 in which the ratio of the particle size of conductive particles P5 to the thickness of the anisotropic conductive composition was 0.2 times and 1.5 times, the repairability was improved. Was good, but the conductivity or non-leakage was low. On the other hand, when the samples S13 to S17 in which the ratio of the particle diameter of the conductive particles P5 to the thickness of the anisotropic conductive composition is 0.3 to 1.2 times are used, conductivity, non-leakage, and repair All properties were good. Note that if the ratio of the particle size of the conductive particles P5 to the thickness of the anisotropic conductive composition satisfies the above-mentioned formula (2), the conductivity, non-leakage property, and repairability can be improved. It was confirmed that everything was good.
[0058]
Next, as shown in Table 7 below, samples S19 to S23 of the anisotropic conductive composition were prepared using styrene-ethylene copolymers having various styrene contents in Sample S9, and the same as Samples S1 to S6. The conductivity, non-leakage property and repairability were examined by the method described in Table 1, and the results are shown in Table 8 below.
[0059]
[Table 7]

[0060]
[Table 8]

[0061]
As shown in Table 8, when samples S19 and S23 in which the styrene content of the styrene-ethylene copolymer was 18% or 67% were used, the non-leakage was good, but the conductivity or the repairability was low. It is had. On the other hand, when samples S20 to S22 in which the styrene content of the styrene-ethylene copolymer was in the range of 24% to 52% were used, all of the conductivity, the non-leakage property, and the repairability were good. In addition, if the styrene content of the styrene-ethylene copolymer is in the range of 20% to 60%, it is confirmed that the conductivity, the non-leak property, and the repairability are all good. did.
[0062]
Next, in the sample S5, as shown in Table 9 below, instead of the conductive particles P5, a brass powder (average particle size: 30 μm) or nica beads (average particle size: 30 μm) was used to obtain a sample S24 of the anisotropic conductive composition , S25 were prepared, and the conductivity, non-leakage property, and repairability were examined in the same manner as for the samples S1 to S6. The results are shown in Table 10 below.
[0063]
[Table 9]

[0064]
[Table 10]

[0065]
As shown in Table 10, the samples S24 and S25 using the brass powder or the nica beads as the conductive particles were all excellent in the conductivity, the non-leakage property, and the repairability like the sample S5. Note that, for example, instead of silver, the conductive particles P5 are coated with various metals (for example, highly conductive metals such as nickel, gold, and copper), and conductive particles satisfying the above formulas (1) and (2) are used. It is clear that the conductivity, non-leakage and repairability are all good with the anisotropic conductive composition thus obtained.
[0066]
As described above, in the present invention, only the described specific examples have been described in detail, but it is apparent to those skilled in the art that various modifications and variations are possible within the technical idea of the present invention. It is obvious that such changes and modifications belong to the scope of the claims.
[0067]
For example, in this embodiment, a mixed solution in which an insulating polymer material, conductive particles, and a solvent (toluene) are mixed under predetermined conditions is used, and the mixed solution is applied in a thin film form and dried to form an anisotropic conductive material. Although the anisotropic conductive composition was prepared, not only the insulating polymer material, the conductive particles, and the solvent but also various additives may be added to the mixed liquid according to the intended use of the anisotropic conductive composition. .
[0068]
Further, in the present embodiment, the powder coated with a metal on the surface is used as the conductive particles. However, for example, even if the whole powder is made of metal, the above-mentioned formulas (1) and (2) are satisfied. It is clear that the conductive particles of the anisotropic conductive composition have good conductivity, non-leak property and repairability as long as they are conductive particles.
[0069]
【The invention's effect】
In the anisotropic conductive composition of the present invention as described above, it can be manufactured by a simple manufacturing process as compared with the conventional anisotropic conductive composition used for connection of opposed objects to be connected. Can be.
[0070]
In addition, the anisotropic conductive composition is simply interposed between the opposing connected objects without being heated (pressed to the extent that the anisotropic conductive composition is sandwiched between both terminals of the opposing connected objects). Thus, a desired anisotropic conduction can be achieved.
[0071]
Further, for example, when used in a burn-in test device for a semiconductor device, the electrodes and the like of the semiconductor device are not immersed in the anisotropic conductive composition and compressed, and the electrodes of the semiconductor device and the electrode terminals of the IC inspection substrate are simply connected. Anisotropic conductive composition is interposed between them (pressing the electrode of the semiconductor device and the electrode terminal of the IC inspection substrate to such an extent that the anisotropic conductive composition is brought into contact with the anisotropic conductive composition) and performing a desired test (anisotropic Conduction).
[0072]
Therefore, according to the anisotropic conductive composition of the present invention, good durability and connection reliability can be obtained, sufficient repairability can be secured, and the production cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view of an anisotropic conductive elastic body composition according to the present embodiment.
FIG. 2 is a schematic explanatory view showing a usage example of the anisotropic conductive elastic composition in the present embodiment.
FIG. 3 is a schematic explanatory view showing a method for measuring conductivity according to the present embodiment.
FIG. 4 is a schematic explanatory view showing a method for measuring non-leakage and repairability of the present embodiment.
[Explanation of symbols]
10, 23: Anisotropic conductive elastic composition
11 ... conductive particles
12, 13 ... Connection target
32 ... sample

Claims

An anisotropic conductive elastic composition which is composed of a mixture containing at least an insulating polymer material and conductive particles and is used for connection of opposed objects to be connected,
The average particle size and the particle size of the conductive particles are respectively defined according to the insulation width of each of the opposed terminals to be connected and the thickness of the anisotropic conductive elastic composition. Anisotropically conductive elastic composition.

Average particle size of the conductive particles D _AVE. Is 0.5 × d <D _{AVE., Where} d is the insulation width of each of the opposed terminals to be connected _. <D
The particle diameter D of the conductive particles satisfies 0.3 × t ≦ D ≦ 1.2 × t, where t is the thickness of the anisotropic conductive elastic body composition. Anisotropic conductive elastic body composition of the above.

The anisotropic conductive elastic body composition according to claim 1, wherein the conductive particles are blended in a range of 1.5 vol% to 13 vol%.

The anisotropic conductive elastic composition according to any one of claims 1 to 3, wherein the insulating polymer material comprises a styrene-ethylene copolymer having a styrene content of 20% to 60%.

A method for producing an anisotropic conductive elastic composition, comprising at least an insulating polymer material and a mixture containing conductive particles, used for connection of opposed objects to be connected,
After the mixture is varnished and applied to the surface of the supported member, the mixture is dried to form a thin film,
The average particle size and the particle size of the conductive particles are defined according to the insulation width of each of the opposed terminals to be connected and the thickness of the anisotropic conductive elastic composition. A method for producing an anisotropic conductive elastic composition.