JP4112024B2

JP4112024B2 - Circuit connection member

Info

Publication number: JP4112024B2
Application number: JP30266395A
Authority: JP
Inventors: 俊之柳川; 貢藤縄; 伊津夫渡辺
Original assignee: Hitachi Chemical Co Ltd; Showa Denko Materials Co Ltd
Current assignee: Showa Denko Materials Co Ltd
Priority date: 1995-11-21
Filing date: 1995-11-21
Publication date: 2008-07-02
Anticipated expiration: 2015-11-21
Also published as: JPH09147946A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば液晶パネル等において、２つの回路基板同士の電極間に形成し、両電極を接続するのに好適な回路用接続部材に関するものである。
【０００２】
【従来の技術】
２つの回路基板同士を接着すると共に、これらの電極間に電気的導通を得る回路接続部材として、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と導電粒子からなる回路接続部材が一般に知られている。この回路接続部材を用いて、液晶パネルのＩＴＯ電極とＴＡＢとを接続する場合、通常、まず液晶パネルのＩＴＯ電極に回路接続部材を加熱加圧（仮接続）し、次に仮接続した回路接続部材上にＴＡＢを加熱加圧し（本接続）して、液晶パネルとＴＡＢを接着すると共に、これらの端子間を導電性粒子により電気的に接続する。この場合、ＩＴＯ電極上に回路接続部材を仮接続した後、ＴＡＢなどの電極パターンとの位置合わせを行うために、ＩＴＯ電極のパターンとＴＡＢなどの電極パターンを認識する必要がある。通常、このパターンを認識する工程は、図１に示したように、回路接続部材ａを仮接続した液晶パネル１上のＩＴＯ電極２をＣＣＤカメラ３を使用して同軸光で認識するものである。
【０００３】
【発明が解決しようとする課題】
図２に示したように、ＩＴＯでの反射光ｂはガラスでの反射光ｃよりも強度が強いため、回路接続部材がパネルに仮接続されてない場合はＩＴＯとガラスのコントラストが得られる。しかし、回路接続部材ａが仮接続されてパネル上に存在する場合、図３に示したように従来のエポキシ樹脂を主成分とした回路接続部材ａの表面であるａ−１面での反射が生じる。従来のエポキシ樹脂を主成分とした回路接続部材ａは波長４００〜９００ｎｍ域での透過率が高いため、この反射光ｅによりＩＴＯとガラスのコントラストが悪くなる。さらに、回路接続部材ａ−１面には凹凸が存在するために反射光ｅの透過光ｆ−１、ｆ−２には強度差によるコントラストが生じる。これをＣＣＤカメラが誤認識するといった問題が生じる。
【０００４】
【課題を解決するための手段】
本発明は、（１）フェノキシ樹脂
（２）エポキシ樹脂
（３）潜在性硬化剤
（４）平均粒径が２〜１８μｍの導電性粒子
（５）絶縁性粒子として平均粒径０．１〜０．４μｍの酸化チタンの成分を必須とする回路用接続部材であって、前記（５）平均粒径０．１〜０．４μｍの酸化チタンの含有量が接着剤組成物１００体積％に対して、０．１〜１０体積％であり、仮接続後における波長４００〜９００ｎｍ域での透過率が５０％以下であることを特徴とする回路用接続部材に関する。
【０００５】
【発明の実施の形態】
本発明に用いるフェノキシ樹脂について説明する。フェノキシ樹脂は、高速液体クロマトグラフィー（ＨＬＣ）から求められた分子量が１００００以上の高分子量エポキシ樹脂に相当し、エポキシ樹脂と同様に他にビスフェノールＡ型、ＡＤ型、ＡＦ型等の種類がある。これらはエポキシ樹脂と構造が類似していることから相溶性がよく、また接着性も良好な特徴を有する。分子量の大きい程フィルム形成性が容易に得られ、また接続時の流動性に影響する溶融粘度を広範囲に設定できる。平均分子量としては１００００〜８００００程度のものが溶融粘度や他の樹脂との相溶性等の点からより好ましい。これらの樹脂は、水酸基やカルボキシル基等の極性基等を含有すると、エポキシ樹脂との相溶性が向上し、均一な外観や特性を有するフィルムが得られることや、硬化時の反応促進による短時間硬化を得る点からも好ましい。配合量としては、フィルム形成性や硬化反応の促進の点から樹脂成分全体に対して２０〜８０重量％とするのが好ましい。また溶融粘度調整等のために、スチレン系樹脂やアクリル樹脂等を適宜混合してもよい。
【０００６】
本発明に用いるエポキシ樹脂は、エピクロルヒドリンとビスフェノールＡやＦ、ＡＤ等から誘導されるビスフェノール型エポキシ樹脂、エピクロルヒドリンとフェノールノボラックやクレゾールノボラックから誘導されるエポキシノボラック樹脂やナフタレン環を含んだ骨格を有するナフタレン系エポキシ樹脂、グリシジルアミン、グリシジルエステル、ビフェニル、脂環式等の１分子内に２個以上のグリシジル基を有する各種のエポキシ化合物等を単独にあるいは２種以上を混合して用いることが可能である。これらのエポキシ樹脂は、不純物イオン（Ｎａ^＋、Ｃｌ⁻等）や、加水分解性塩素等を３００ｐｐｍ以下に低減した高純度品を用いることがエレクトロンマイグレーション防止のために好ましい。
【０００７】
潜在性硬化剤としては、イミダゾール系、ヒドラジド系、三フッ化ホウ素−アミン錯体、スルホニウム塩、アミンイミド、ジアミノマレオニトリル、メラミンおよびその誘導体、ポリアミンの塩、ジシアンジアミド等、及びこれらの変性物があり、これらは単独あるいは２種以上の混合体として使用できる。これらはアニオンまたはカチオン重合性の触媒型硬化剤であり、速硬化性を得やすく、また化学当量的な考慮が少なくてよいことから好ましい。硬化剤としては、その他にポリアミン類、ポリメルカプタン、ポリフェノール、酸無水物等の重付加型の適用や前記触媒型硬化剤との併用も可能である。
【０００８】
アニオン重合型の触媒型硬化剤としては、第３アミン類やイミダゾール類が主として用いられる。第３アミン類やイミダゾール類を配合したエポキシ樹脂は、１６０〜２００℃程度の中温で数１０秒〜数時間程度の加熱により硬化するために可使時間（ポットライフ）が比較的長い。
【０００９】
カチオン重合型の触媒型硬化剤としては、エネルギー線照射により樹脂を硬化させる感光性オニウム塩、例えば、芳香族ジアゾニウム塩、芳香族スルホニウム塩等が主として用いられる。またエネルギー線照射以外に加熱によっても活性化してエポキシ樹脂を硬化させるものとして、脂肪族スルホニウム塩等がある。この種の硬化剤は速硬化性という特徴を有することから好ましい。
【００１０】
これらの硬化剤をポリウレタン系、ポリエステル系等の高分子物質や、Ｎｉ、Ｃｕ等の金属薄膜及びケイ酸カルシウム等の無機物で被覆してマイクロカプセル化したものは、可使時間が延長できるため好ましい。
【００１１】
上記で得た接着剤組成物中には、通常の添加剤等として例えば、充填剤、軟化剤、促進剤、老化防止剤、着色剤、難燃剤、チキソトロピック剤、カップリング剤及びフェノール樹脂やメラミン樹脂、イソシアネート類等の硬化剤等を含有することもできる。
【００１２】
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、これら及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り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、加熱加圧により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体積に対して０．１〜３０体積％の広範囲で用途により使い分ける。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０．１〜１０体積％とするのがより好ましい。
【００１３】
絶縁性粒子としては、ポリスチレン、アクリル等の熱変形性を有する有機物やシリカ、酸化亜鉛、酸化チタン等の無機物があり、表面を接着剤組成物中での分散性を向上するために有機シラン等で表面処理してもよい。本発明では、絶縁性粒子として酸化チタンを用いる。絶縁性粒子の平均粒子径が０．１μｍ未満の場合は４００〜９００ｎｍ域での光線透過率が高く、回路接続部材の光線透過率を低下させる効果が少ない。また、絶縁性粒子の平均粒子径が導電性粒子の粒子径よりも大きい場合は、導電粒子による接続が得にくい。絶縁性粒子は、接着剤成分１００体積％に対して、０．１〜１０体積％の中で回路接続部材の４００〜９００ｎｍ域での光線透過率を５０％以下に調整するために使い分けられる。１０体積％を超える場合は、導電粒子による接続が得にくく、０．１体積％未満では、４００〜９００ｎｍ域での光線透過率を低下させる効果が少ない。特に好適な配合量は０．５〜５体積％である。
【００１４】
本発明の接着剤組成物は一液型接着剤として、とりわけ液晶パネル接着用のフィルム状接着剤として特に有用である。この場合例えば、上記で得た接着剤組成物を溶剤あるいはエマルジョンの場合の分散液等として液状化して、離形紙等の剥離性基材上に形成し、あるいは不織布等の基材に前記配合液を含浸させて剥離性基材上に形成し、硬化剤の活性温度以下で乾燥し、溶剤あるいは分散液等を除去すればよい。この時、用いる溶剤は芳香族炭化水素系と含酸素系の混合溶剤が、材料の溶解性を向上させるため好ましい。ここに含酸素系溶剤のＳＰ値は８．１〜１０．７の範囲とすることが潜在性硬化剤の保護上好ましく、酢酸エステル類がより好ましい。また溶剤の沸点は１５０℃以下が適用できる。沸点が１５０℃を超すと乾燥に高温を要し、潜在性硬化剤の活性温度に近いことから潜在性の低下を招き、低温では乾燥時の作業性が低下する。このため沸点が６０〜１５０℃が好ましく、７０〜１３０℃がより好ましい。
【００１５】
本発明で得た接続材料を用いた電極の接続について説明する。この方法は、回路用接続部材を基板上の相対峙する電極間に形成し、加熱加圧により両電極の接触と基板間の接着を得る電極の接続方法である。電極を形成する基板としては、半導体、ガラス、セラミック等の無機質、ポリイミド、ポリカーボネート等の有機物、ガラス／エポキシ等のこれら複合の各組み合わせが適用できる。
【００１６】
本発明においては、従来と同等の接続性が得られると同時に、本接続前の仮接続時の作業性が向上した回路接続部材が得られる。
【００１７】
【実施例】
以下、本発明を実施例に基づいて詳細に説明する。
実施例１
ビスフェノールＡとエピクロルヒドリンから、ビスフェノールＡ型フェノキシ樹脂（平均分子量３００００）６０ｇを一般的方法により作製し、これ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の混合溶剤に溶解して、固形分４０％の溶液とした。ナフタレン系エポキシ樹脂（ナフタレンジオール系エポキシ樹脂、大日本インキ化学工業株式会社製、商品名ＨＰ−４０３２、エポキシ当量１４９、加水分解性塩素１３０ｐｐｍ）２０ｇを重量比でトルエン／酢酸エチル＝５０／５０の混合溶剤に溶解して、固形分８０％の溶液とした。スチレン系樹脂（スチレン−無水マレイン酸共重合樹脂、積水化成品工業株式会社製、商品名ダイラーク＃２５０、熱変形温度１１２℃）２０ｇをトルエンに溶解して、固形分４０％の溶液とした。潜在性硬化剤は、ノバキュア３９４１ＨＰＳ（イミダゾール変性体を核とし、その表面をポリウレタンで被覆してなる平均粒径５μｍのマイクロカプセル型硬化剤を、液状ビスフェノールＦ型エポキシ樹脂中に分散してなるマスターバッチ型硬化剤、活性温度１２５℃、旭化成工業株式会社製商品名）を用いた。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、さらに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。絶縁性粒子としてＴＭ−１（酸化チタン、平均粒子径０．４μｍ、富士チタニウム（株）製商品名）を用いた。固形重量比で樹脂成分１００、潜在性硬化剤１００となるように配合し、さらに、導電性粒子を３体積％、絶縁性粒子を０．５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、７５℃、１０分の熱風乾燥により接着剤層の厚みが１８μｍの回路用接続部材を得た。
【００１８】
実施例２
潜在性硬化剤をマイクロカプセル型硬化剤に代えて、ｐ−アセトキシフェニルベンジルスルホニウム塩の５０重量％酢酸エチル溶液（三新化学工業株式会社製、商品名サンエイドＳＩ−６０Ｌ）とし、かつ固形重量比で樹脂成分１００に対して５となるように配合した他は、実施例１と同様にして回路用接続部材を得た。
【００１９】
実施例３
導電性粒子を、平均粒径２μｍ、凝集粒径１０μｍのニッケル粒子に代えた他は、実施例１と同様にして回路用接続部材を得た。
【００２０】
実施例４
導電性粒子を、平均粒径１０μｍに代えた他は、実施例１と同様にして回路用接続部材を得た。
【００２１】
実施例５
絶縁性粒子を、平均粒径０．２５μｍ（ＣＲ−ＥＬ、酸化チタン、石原産業（株）製商品名）に代えた他は、実施例１と同様にして回路用接続部材を得た。
【００２２】
実施例６
絶縁性粒子を、平均粒径０．２５μｍ、表面処理品（ＣＲ−８０、酸化チタン、石原産業（株）製商品名）に代えた他は、実施例１と同様にして回路用接続部材を得た。
【００２３】
比較例１
絶縁性粒子の配合量を１５体積％に代えた他は、実施例１と同様にして回路用接続部材を得た。
【００２４】
比較例２
絶縁性粒子を混合せずに、実施例１と同様にして回路用接続部材を得た。
【００２５】
比較例３
絶縁性粒子の平均粒径を０．０５μｍとした他は、実施例１と同様にして回路用接続部材を得た。
【００２６】
比較例４
絶縁性粒子の配合量を０．０５体積％に代えた他は、実施例１と同様にして回路用接続部材を得た。
【００２７】
（回路の接続）
上述の回路用接続部材を用いて、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）同士を１７０℃、３ＭＰａで２０秒間加熱加圧して幅２ｍｍにわたり接続した。この時、予め一方のＦＰＣ上に回路用接続部材の接着面を貼り付けた後、８０℃、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ＦＰＣと接続した。また、前述のＦＰＣと酸化インジウム（ＩＴＯ）の薄層を形成したガラス（表面抵抗２０Ω／□）とを１６０℃、３ＭＰａで２０秒間加熱加圧して幅２ｍｍにわたり接続した。この時、上記と同様にＩＴＯガラスに仮接続を行った。
【００２８】
（接続抵抗の測定）
回路の接続後、上記接続部を含むＦＰＣの隣接回路間の抵抗値を、初期と、８５℃、８５％ＲＨの恒温恒湿槽中に５００時間保持した後にマルチメータで測定した。抵抗値は隣接回路間の抵抗１５０点の平均（ｘ＋３σ）で示した。
【００２９】
（パターン認識性）
ピッチ１００μｍのＩＴＯパターンを形成したガラス上に、厚さ１８μｍの回路接続部材を８０℃、０．５ＭＰａで５秒間加熱加圧して仮接続し、同軸光を用いてガラス側からＣＣＤカメラを通して画像認識し、その画像において、ＩＴＯパターンが明確に認識できる場合を「〇」、不明確にしか認識できない場合を「△」、認識できない場合を「×」と評価した。
【００３０】
（透過率の測定）
ガラス上に厚さ１８μｍの回路接続部材を８０℃、０．５ＭＰａで５秒間加熱加圧して仮接続し、波長４００〜９００ｎｍ域の光線透過率をダブルビーム分光光度計（日立製作所製、モデル２００−１０）を用いて測定した。これらの結果を表１に示した。
【００３１】
【表１】

【００３２】
【発明の効果】
以上詳述したように本発明によれば、接続信頼性および作業性に優れた回路用接続部材を提供することが可能となった。
【図面の簡単な説明】
【図１】パターン認識の概念を説明するための側面断面図。
【図２】位置あわせの状況を示す側面断面図。
【図３】位置あわせ時の光線の状況を示す側面断面図。
【符号の説明】
１液晶パネル２ＩＴＯパターン
３ＣＣＤカメラ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit connection member which is formed between electrodes of two circuit boards in a liquid crystal panel or the like and is suitable for connecting both electrodes.
[0002]
[Prior art]
As a circuit connecting member that bonds two circuit boards together and obtains electrical continuity between these electrodes, it conducts with thermoplastic materials such as styrene and polyester, and thermosetting materials such as epoxy and silicone. A circuit connecting member made of particles is generally known. When this circuit connection member is used to connect an ITO electrode of a liquid crystal panel and a TAB, the circuit connection member is usually first heated and pressurized (temporary connection) to the ITO electrode of the liquid crystal panel, and then temporarily connected to the circuit connection. The TAB is heated and pressurized (main connection) on the member to bond the liquid crystal panel and the TAB, and the terminals are electrically connected by conductive particles. In this case, after temporarily connecting the circuit connection member on the ITO electrode, it is necessary to recognize the pattern of the ITO electrode and the electrode pattern such as TAB in order to perform alignment with the electrode pattern such as TAB. Usually, in the step of recognizing this pattern, as shown in FIG. 1, the ITO electrode 2 on the liquid crystal panel 1 to which the circuit connection member a is temporarily connected is recognized by coaxial light using a CCD camera 3. .
[0003]
[Problems to be solved by the invention]
As shown in FIG. 2, since the reflected light b from ITO has a stronger intensity than the reflected light c from glass, the contrast between ITO and glass can be obtained when the circuit connecting member is not temporarily connected to the panel. However, when the circuit connection member a is temporarily connected and exists on the panel, the reflection on the surface a-1 which is the surface of the circuit connection member a mainly composed of a conventional epoxy resin as shown in FIG. Arise. Since the conventional circuit connection member a mainly composed of an epoxy resin has high transmittance in the wavelength range of 400 to 900 nm, the reflected light e deteriorates the contrast between ITO and glass. Further, since the surface of the circuit connecting member a-1 has irregularities, the transmitted light f-1 and f-2 of the reflected light e has a contrast due to an intensity difference. There arises a problem that this is erroneously recognized by the CCD camera.
[0004]
[Means for Solving the Problems]
The present invention provides (1) a phenoxy resin (2) Average particle diameter as the epoxy resin (3) latent curing agent (4) Average particle diameter 2~18μm of the conductive particles (5) insulating particles 0.1 to 0 .4 μm titanium oxide component essential component, (5) content of titanium oxide having an average particle size of 0.1 to 0.4 μm with respect to 100 % by volume of the adhesive composition Further, the present invention relates to a circuit connection member, wherein the transmittance in a wavelength range of 400 to 900 nm after temporary connection is 50% or less.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The phenoxy resin used in the present invention will be described. The phenoxy resin corresponds to a high molecular weight epoxy resin having a molecular weight of 10,000 or more determined by high performance liquid chromatography (HLC), and there are other types such as bisphenol A type, AD type, and AF type as well as the epoxy resin. Since these are similar in structure to epoxy resins, they have good compatibility and also have good adhesive properties. The higher the molecular weight, the easier the film-forming property is obtained, and the melt viscosity that affects the fluidity during connection can be set in a wide range. An average molecular weight of about 10,000 to 80,000 is more preferable from the viewpoints of melt viscosity and compatibility with other resins. When these resins contain polar groups such as hydroxyl groups and carboxyl groups, the compatibility with the epoxy resin is improved, and a film having a uniform appearance and characteristics can be obtained, and the reaction at the time of curing is accelerated. It is also preferable from the viewpoint of obtaining curing. As a compounding quantity, it is preferable to set it as 20 to 80 weight% with respect to the whole resin component from the point of acceleration | stimulation of film formation property or hardening reaction. Further, a styrene resin, an acrylic resin, or the like may be appropriately mixed for adjusting the melt viscosity.
[0006]
The epoxy resin used in the present invention is a bisphenol type epoxy resin derived from epichlorohydrin and bisphenol A, F, AD or the like, an epoxy novolac resin derived from epichlorohydrin and phenol novolak or cresol novolac, or a naphthalene having a skeleton containing a naphthalene ring. Various epoxy compounds having two or more glycidyl groups in one molecule such as epoxy resin, glycidylamine, glycidyl ester, biphenyl, alicyclic, etc. can be used alone or in admixture of two or more. is there. For these epoxy resins, it is preferable to use a high-purity product in which impurity ions (Na ⁺ , Cl ^−, etc.), hydrolyzable chlorine and the like are reduced to 300 ppm or less, in order to prevent electron migration.
[0007]
Examples of latent curing agents include imidazole series, hydrazide series, boron trifluoride-amine complexes, sulfonium salts, amine imides, diaminomaleonitrile, melamine and derivatives thereof, polyamine salts, dicyandiamide, and modified products thereof. These can be used alone or as a mixture of two or more. These are anionic or cationic polymerizable catalyst-type curing agents, which are preferable because they are easy to obtain fast curability and require less chemical equivalent considerations. As the curing agent, other polyaddition types such as polyamines, polymercaptans, polyphenols, and acid anhydrides, and the combined use with the catalyst-type curing agent can be used.
[0008]
Tertiary amines and imidazoles are mainly used as anionic polymerization type catalyst type curing agents. Epoxy resins containing tertiary amines and imidazoles have a relatively long pot life (pot life) because they are cured by heating at a medium temperature of about 160 to 200 ° C. for several tens of seconds to several hours.
[0009]
As the cationic polymerization type catalyst-type curing agent, a photosensitive onium salt that cures the resin by energy ray irradiation, for example, an aromatic diazonium salt, an aromatic sulfonium salt, or the like is mainly used. In addition to irradiation with energy rays, aliphatic sulfonium salts and the like are also activated by heating to cure the epoxy resin. This type of curing agent is preferred because it has the property of fast curing.
[0010]
It is preferable to use these hardeners coated with a polymer material such as polyurethane or polyester, a metal thin film such as Ni or Cu, and an inorganic material such as calcium silicate so that the pot life can be extended. .
[0011]
In the adhesive composition obtained above, as usual additives, for example, fillers, softeners, accelerators, anti-aging agents, colorants, flame retardants, thixotropic agents, coupling agents and phenol resins, Curing agents such as melamine resins and isocyanates can also be contained.
[0012]
Examples of the conductive particles include metal particles such as Au, Ag, Ni, Cu, and solder, carbon, and the like, and those in which the conductive layer described above is formed by coating or the like on non-conductive glass, ceramic, plastic, or the like. Good. 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 reliability is improved. The conductive particles are properly used depending on the application in a wide range of 0.1 to 30% by volume with respect to 100 volumes of the adhesive component. In order to prevent an adjacent circuit from being short-circuited by excessive conductive particles, the content is more preferably 0.1 to 10% by volume.
[0013]
Insulating particles include heat-deformable organic materials such as polystyrene and acrylic, and inorganic materials such as silica, zinc oxide, and titanium oxide. The surface of the particles is improved to improve dispersibility in the adhesive composition. You may surface-treat with. In the present invention, titanium oxide is used as the insulating particles. When the average particle diameter of the insulating particles is less than 0.1 μm, the light transmittance in the 400 to 900 nm region is high, and the effect of reducing the light transmittance of the circuit connecting member is small. Further, when the average particle size of the insulating particles is larger than the particle size of the conductive particles, it is difficult to obtain a connection with the conductive particles. The insulating particles are properly used for adjusting the light transmittance in the 400 to 900 nm region of the circuit connecting member to 50% or less in 0.1 to 10% by volume with respect to 100% by volume of the adhesive component. If it exceeds 10% by volume, it is difficult to obtain a connection by conductive particles, and if it is less than 0.1% by volume, the effect of reducing the light transmittance in the 400 to 900 nm region is small. A particularly suitable blending amount is 0.5 to 5% by volume.
[0014]
The adhesive composition of the present invention is particularly useful as a one-component adhesive, particularly as a film adhesive for liquid crystal panel adhesion. In this case, for example, the adhesive composition obtained above is liquefied as a dispersion or the like in the case of a solvent or emulsion, and formed on a peelable substrate such as a release paper, or the above-mentioned compounding in a substrate such as a nonwoven fabric The solution may be impregnated to form on a peelable substrate, dried at a temperature lower than the activation temperature of the curing agent, and the solvent or dispersion may be removed. At this time, the solvent to be used is preferably an aromatic hydrocarbon-based and oxygen-containing mixed solvent in order to improve the solubility of the material. Here, the SP value of the oxygen-containing solvent is preferably in the range of 8.1 to 10.7 in terms of protecting the latent curing agent, and acetates are more preferable. The boiling point of the solvent can be 150 ° C. or less. When the boiling point exceeds 150 ° C., a high temperature is required for drying, and since the temperature is close to the activation temperature of the latent curing agent, the potential is lowered, and at a low temperature, the workability during drying is lowered. For this reason, the boiling point is preferably 60 to 150 ° C, more preferably 70 to 130 ° C.
[0015]
Connection of electrodes using the connection material obtained in the present invention will be described. This method is an electrode connection method in which a circuit connection member is formed between opposing electrodes on a substrate, and contact between both electrodes and adhesion between the substrates are obtained by heating and pressing. As the substrate for forming the electrodes, semiconductors, inorganic substances such as glass and ceramics, organic substances such as polyimide and polycarbonate, and combinations of these composites such as glass / epoxy can be applied.
[0016]
In the present invention, it is possible to obtain a circuit connecting member that can obtain the same connectivity as that of the prior art and at the same time the workability at the time of temporary connection before the main connection.
[0017]
【Example】
Hereinafter, the present invention will be described in detail based on examples.
Example 1
From bisphenol A and epichlorohydrin, 60 g of bisphenol A-type phenoxy resin (average molecular weight 30000) was prepared by a general method, and this was prepared by toluene (boiling point 110.6 ° C., SP value 8.90) / ethyl acetate (boiling point 77). .1 ° C., SP value 9.10) = dissolved in a 50/50 mixed solvent to obtain a solution having a solid content of 40%. 20 g of naphthalene epoxy resin (naphthalene diol epoxy resin, manufactured by Dainippon Ink and Chemicals, trade name HP-4032, epoxy equivalent 149, hydrolyzable chlorine 130 ppm) in a weight ratio of toluene / ethyl acetate = 50/50 It melt | dissolved in the mixed solvent and it was set as the solution of 80% of solid content. 20 g of a styrene-based resin (styrene-maleic anhydride copolymer resin, manufactured by Sekisui Plastics Co., Ltd., trade name: Dilark # 250, heat distortion temperature: 112 ° C.) was dissolved in toluene to obtain a solution having a solid content of 40%. The latent curing agent is Novacure 3941 HPS (a master capsule obtained by dispersing a microcapsule type curing agent having an average particle diameter of 5 μm having an imidazole-modified product as a core and coated with polyurethane on a liquid bisphenol F-type epoxy resin. A batch type curing agent, an active temperature of 125 ° C., a trade name of Asahi Kasei Kogyo Co., Ltd.) was used. 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. TM-1 (titanium oxide, average particle size 0.4 μm, trade name, manufactured by Fuji Titanium Co., Ltd.) was used as the insulating particles. The resin component 100 and the latent curing agent 100 are blended at a solid weight ratio, and further 3% by volume of conductive particles and 0.5% by volume of insulating particles are mixed and dispersed into a fluororesin film having a thickness of 80 μm. It applied using the coating apparatus, and the connection member for circuits whose thickness of an adhesive bond layer is 18 micrometers was obtained by 75 degreeC and hot-air drying for 10 minutes.
[0018]
Example 2
The latent curing agent is replaced with a microcapsule type curing agent, and a 50% by weight ethyl acetate solution of p-acetoxyphenylbenzylsulfonium salt (manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sun-Aid SI-60L) is used. A circuit connection member was obtained in the same manner as in Example 1 except that the amount was 5 to the resin component 100.
[0019]
Example 3
A circuit connection member was obtained in the same manner as in Example 1 except that the conductive particles were replaced with nickel particles having an average particle diameter of 2 μm and an aggregate particle diameter of 10 μm.
[0020]
Example 4
A circuit connection member was obtained in the same manner as in Example 1 except that the conductive particles were changed to an average particle size of 10 μm.
[0021]
Example 5
A circuit connection member was obtained in the same manner as in Example 1 except that the insulating particles were replaced with an average particle size of 0.25 μm (CR-EL, titanium oxide, trade name, manufactured by Ishihara Sangyo Co., Ltd.).
[0022]
Example 6
The connection member for a circuit was prepared in the same manner as in Example 1 except that the insulating particles were replaced with an average particle size of 0.25 μm and a surface-treated product (CR-80, titanium oxide, product name manufactured by Ishihara Sangyo Co., Ltd.). Obtained.
[0023]
Comparative Example 1
A circuit connection member was obtained in the same manner as in Example 1 except that the blending amount of the insulating particles was changed to 15% by volume.
[0024]
Comparative Example 2
A circuit connection member was obtained in the same manner as in Example 1 without mixing the insulating particles.
[0025]
Comparative Example 3
A circuit connection member was obtained in the same manner as in Example 1 except that the average particle diameter of the insulating particles was 0.05 μm.
[0026]
Comparative Example 4
A circuit connection member was obtained in the same manner as in Example 1 except that the blending amount of the insulating particles was changed to 0.05% by volume.
[0027]
(Circuit connection)
Using the circuit connection member described above, flexible circuit boards (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm were heated and pressurized at 170 ° C. and 3 MPa for 20 seconds to be connected over a width of 2 mm. . At this time, after pasting the adhesive surface of the circuit connecting member on one FPC in advance, it was temporarily connected by heating and pressing at 80 ° C. and 0.5 MPa for 5 seconds, and then the fluororesin film was peeled off and the other Connected to the FPC. Further, the FPC and glass (surface resistance 20Ω / □) on which a thin layer of indium oxide (ITO) was formed were heated and pressed at 160 ° C. and 3 MPa for 20 seconds to be connected over a width of 2 mm. At this time, temporary connection was made to ITO glass in the same manner as described above.
[0028]
(Measurement of connection resistance)
After the circuit connection, the resistance value between the adjacent circuits of the FPC including the connection portion was measured with a multimeter at the initial stage and after being held in a constant temperature and humidity chamber at 85 ° C. and 85% RH for 500 hours. The resistance value is shown as an average (x + 3σ) of 150 resistances between adjacent circuits.
[0029]
(Pattern recognition)
On a glass with an ITO pattern with a pitch of 100 μm, a circuit connection member with a thickness of 18 μm is temporarily connected by heating and pressing at 80 ° C. and 0.5 MPa for 5 seconds, and image recognition is performed from the glass side through a CCD camera using coaxial light. In the image, the case where the ITO pattern was clearly recognizable was evaluated as “◯”, the case where it could be recognized only unclearly as “Δ”, and the case where it could not be recognized as “X”.
[0030]
(Measurement of transmittance)
A circuit connection member having a thickness of 18 μm is temporarily connected to glass by heating and pressing at 80 ° C. and 0.5 MPa for 5 seconds, and a light transmittance in a wavelength range of 400 to 900 nm is measured with a double beam spectrophotometer (model 200, manufactured by Hitachi, Ltd.). -10). These results are shown in Table 1.
[0031]
[Table 1]

[0032]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a circuit connection member having excellent connection reliability and workability.
[Brief description of the drawings]
FIG. 1 is a side cross-sectional view for explaining the concept of pattern recognition.
FIG. 2 is a side cross-sectional view showing a state of alignment.
FIG. 3 is a side cross-sectional view showing the state of light rays during alignment.
[Explanation of symbols]
1 LCD panel 2 ITO pattern 3 CCD camera

Claims

(1) Phenoxy resin (2) Epoxy resin (3) Latent curing agent (4) Conductive particles having an average particle diameter of 2 to 18 μm (5) Oxidation having an average particle diameter of 0.1 to 0.4 μm as insulating particles It is a connection member for a circuit which essentially comprises a titanium component, and (5) the content of titanium oxide having an average particle size of 0.1 to 0.4 μm is 0.1 % with respect to 100 % by volume of the adhesive composition. 10% by volume, and a transmissivity in a wavelength range of 400 to 900 nm after temporary connection is 50% or less.

Against 100 vol adhesive composition content of the conductive particles, the circuit connecting member according to claim 1 Symbol mounting, characterized in that from 0.1 to 10% by volume.

The connection member for a circuit according to claim 1 or 2 , wherein the shape is a film shape.