JP2004221312A - Adhesive film for circuit connection and method for connecting the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting method of an adhesive film for circuit connection capable of electrically connecting the circuit electrodes in a low temperature and in a short time and an adhesive film for circuit connection to be used for this. <P>SOLUTION: This heat adhesive film is configured to electrically connect opposite circuit electrodes in a pressed direction by heating and pressing those circuit electrodes. This method for connecting the adhesive film for circuit connection is executed by setting the heating and pressurizing time when connecting those electrodes to three seconds or less under two stage connection conditions, that is, a primary condition that the heating and pressing time is two seconds or less in temperatures ranging from 120°C to 180°C, and a secondary condition that the heating and pressing time is one second or more in temperatures ranging from 180°C to 220°C. This adhesive film for circuit connection to be used for the above mentioned connecting method contains reactive resin to be hardened by heat, the heating start temperature in the differential scanning thermal analysis(DSC) of the adhesive film is set to 60°C or more, and a temperature in which the 60% of the hardening reaction ends is set to 160°C or less. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

一般式（１）中、Ｒ^１は、電子吸引性の基、例えば、ニトロソ基、カルボニル基、カルボキシル基、シアノ基、トリアルキルアンモニウム基、フルオロメチル基、Ｒ^２及びＲ^３は電子供与性の基、例えば、アミノ基、水酸基、メチル基、Ｙ⁻は、非求核性陰イオン例えば、ヘキサフルオロアルセネート、ヘキサフルオロアンチモネートである。
【０００９】
スルホニウム塩のエポキシ樹脂１００重量部に対する配合量は、１〜２０重量部が好ましい。この場合、ＤＳＣにより２つの発熱ピークが出ることがある。ＤＳＣは、測定温度範囲内で、発熱、吸熱の無い標準試料との温度差をたえず打ち消すように熱量を供給または除去するゼロ位法を測定原理とするものであり、市販されている測定装置を用いて測定できる。接着剤の反応は、発熱反応であり、一定の昇温速度で試料を昇温していくと、試料が反応して熱量を発生する。その発熱量をチャートに出力し、ベースラインを基準として発熱曲線とベースラインで囲まれた面積を求め、これを発熱量とする。室温（２５℃）から３００℃程度まで１０℃／分の昇温速度で測定し、上記した発熱量を求める。これらは、全自動で測定を行うものであり、それを使用すると容易に行うことができる。また、硬化反応の６０％（発熱量の６０％）、８０％（発熱量の８０％）が終了する温度は、発熱量の面積から求めることができ、その際の温度である。
【００１０】
本発明において用いられるエポキシ樹脂としては、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、グリシジルエーテル、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。
【００１１】
また、回路接続用接着フィルムにはフィルム形成性をより容易にするために、フェノキシ樹脂、ポリエステル樹脂、ポリアミド樹脂等の熱可塑性樹脂を配合することもできる。これらのフィルム形成性高分子は、反応性樹脂の硬化時の応力緩和に効果がある。特に、フィルム形成性高分子が、水酸基等の官能基を有する場合、接着性が向上するためより好ましい。フィルム形成は、これら少なくとも反応性樹脂、潜在性硬化剤からなる接着組成物を有機溶剤に溶解あるいは分散により、液状化して、剥離性基材上に塗布し、硬化剤の活性温度以下で溶剤を除去することにより行われる。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。
【００１２】
本発明の回路接続用接着剤には、チップのバンプや基板電極の高さばらつきを吸収するために、異方導電性を積極的に付与する目的で導電粒子を混入・分散することもできる。本発明において導電粒子は、例えばＡｕ、Ａｇ、Ｃｕやはんだ等の金属の粒子であり、ポリスチレン等の高分子の球状の核材にＮｉ、Ｃｕ、Ａｕ、はんだ等の導電層を設けたものがより好ましい。さらに導電性の粒子の表面にＳｕ、Ａｕ、はんだ等の表面層を形成することもできる。粒径は基板の電極の最小の間隔よりも小さいことが必要で、電極の高さばらつきがある場合、高さばらつきよりも大きいことが好ましく、１〜１０μｍが好ましい。また、接着剤に分散される導電粒子量は、０．１〜３０体積％であり、好ましくは０．２〜１５体積％である。
【００１３】
本発明の回路接続用接着剤には、無機質充填材やゴム状粒子を混入・分散することができる。
無機質充填材としては、特に制限するものではなく、例えば、溶融シリカ、結晶質シリカ、ケイ酸カルシウム、アルミナ、炭酸カルシウム等の粉体があげられる。無機充填材の配合量は、接着樹脂組成物１００重量部に対して１０〜２００重量部が好ましく、熱膨張係数を低下させるには配合量が大きいほど効果的であるが、多量に配合すると接着性や接続部での接着剤の排除性低下に基づく導通不良が発生するし、配合量が小さいと熱膨張係数を充分低下できないため、２０〜９０重量部がさらに好ましい。また、その平均粒径は、接続部での導通不良を防止する目的で３μｍ以下にするのが好ましい。また接続時の樹脂の流動性の低下及びチップのパッシベーション膜のダメージを防ぐ目的で球状フィラを用いることが望ましい。無機質充填材は、導電粒子と共に又は導電粒子が使用されない層に混入・分散することができる。
【００１４】
接着剤に分散するゴム粒子としては、ガラス転移温度が２５℃以下のゴム粒子であれば特に限定するものではないが、ブタジエンゴム、アクリルゴム、スチレン−ブタジエン−スチレンゴム、ニトリル−ブタジエンゴム、シリコーンゴム等を用いることができ、平均粒径が０．１〜１０μｍのものが用いられ、平均粒径以下の粒子が、粒径分布の８０％以上を占めるゴム粒子が特に好ましく、さらに好ましくは０．１〜５μｍのものが用いられる。また、微粒子表面をシランカップリング剤で処理した場合、反応性樹脂に対する分散性が向上するのでより好ましい。
ゴム粒子の中でシリコーンゴム粒子は、耐溶剤性に優れる他、分散性にも優れるため効果的なゴム粒子として用いることができる。シリコーンゴム粒子はシラン化合物やメチルトリアルコキシシラン及び／またはその部分加水分解縮合物を苛性ソーダやアンモニア等の塩基性物質によりｐＨ＞９に調整したアルコール水溶液に添加し、加水分解、重縮合させる方法やオルガノシロキサンの共重合等で得ることができる。また、分子末端もしくは分子内側鎖に水酸基やエポキシ基、ケチミン、カルボキシル基、メルカプト基などの官能基を含有したシリコーン微粒子は反応性樹脂への分散性が向上するため好ましい。
【００１５】
【実施例】
（実施例１）
フェノキシ樹脂（ユニオンカーバイド社製，ＰＫＨＣ）５０ｇを酢酸エチル１１５ｇに溶解し、３０重量％溶液を得た。
固形重量比でフェノキシ樹脂６０ｇ、平均粒子径０．２μｍのアクリル粒子が２０ｗｔ％分散されたビスフェノールＡ型エポキシ樹脂（エポキシ当量１８０）３０ｇ、ビスフェノールＡ型固形エポキシ樹脂（エポキシ当量：４７０）５ｇ、ｐ−アセトキシフェニルベンジルメチルスルホニウム塩（非求核性陰イオン：ヘキサフルオロアンチモネート）３ｇを配合し、ポリスチレン系核体（直径：３μｍ）の表面にＡｕ層を形成した導電粒子を１０体積％配合分散してフィルム塗工用溶液を得た。ついで、この溶液を厚み５０μｍの片面を表面処理したＰＥＴフィルムに塗工装置を用いて塗布し、７０℃、１０分の熱風乾燥により、接着剤層の厚みが１０μｍのフィルム状接着剤ａを得た。
ついで、前記フィルム塗工用溶液の作製の中で、Ａｕ層を形成した導電粒子を分散しない以外は同様な方法で作製したフィルム塗工用溶液を、厚み５０μｍの片面を表面処理したＰＥＴフィルムに塗工装置を用いて塗布し、７０℃、１０分の熱風乾燥により、接着剤層の厚みが１５μｍのフィルム状接着剤ｂを得た。さらに得られたフィルム状接着剤ａとｂを４０℃で加熱しながら、ロールラミネータでラミネートした二層構成異方導電フィルムを作製した。この接着フィルムのＤＳＣ測定での反応開始温度は８０℃、硬化反応の６０％が終了する温度は１５０℃であった。
次に、作製した異方導電フィルムを用いて、金バンプ（面積：５０×５０μｍ、スペース２０μｍ、高さ：１５μｍ、バンプ数３６２）付きチップ（１．７×１７ｍｍ、厚み：５００μｍ）とＩＴＯ回路付きガラス基板（厚み：１．１ｍｍ）の接続を、以下に示すように行った。異方導電フィルム（２×２０ｍｍ）をＩＴＯ回路付きガラス基板に８０℃、０．９８ＭＰａ（１０ｋｇｆ／ｃｍ^２）で貼り付けた後、セパレータを剥離し、チップのバンプとＩＴＯ回路付きガラス基板の位置合わせを行った。次いで、１次条件が１５０℃、４０ｇ／バンプ、１秒でかつ２次条件が２００℃、４０ｇ／バンプ、１秒である２段階の接続条件でチップ上方から加熱、加圧を行い、本接続を行った。本接続後の接続抵抗は、１バンプあたり最高で５０ｍΩ、平均で２０ｍΩ、絶縁抵抗は１０^８Ω以上であり、これらの値は−４０〜１００℃の熱衝撃試験１０００サイクル処理、高温・高湿（８５℃／８５％ＲＨ、１０００ｈ）試験後においても変化がなく、良好な接続信頼性を示した。
【００１６】
（比較例１）
実施例１で作製した二層構成異方導電フィルムを用い、金バンプ（面積：５０×５０μｍ、スペース２０μｍ、高さ：１５μｍ、バンプ数３６２）付きチップ（１．７×１７ｍｍ、厚み：５００μｍ）とＩＴＯ回路付きガラス基板（厚み：１．１ｍｍ）の接続を、以下に示すように行った。異方導電フィルム（２×２０ｍｍ）をＩＴＯ回路付きガラス基板に８０℃、０．９８ＭＰａ（１０ｋｇｆ／ｃｍ^２）で貼り付けた後、セパレータを剥離し、チップのバンプとＩＴＯ回路付きガラス基板の位置合わせを行った。次いで、２００℃、４０ｇ／バンプ、２秒の接続条件でチップ上方から加熱、加圧を行い、本接続を行った。本接続後の接続抵抗は、１バンプあたり最高で１０Ω、平均で２Ω、絶縁抵抗は１０^８Ω以上であり、これらの値は−４０〜１００℃の熱衝撃試験１０００サイクル処理、高温・高湿（８５℃／８５％ＲＨ、１０００ｈ）試験後において、接続抵抗値が５０Ω以上となり異常を示した。
【００１７】
（比較例２）
日立化成工業株式会社製異方導電フィルムＡＣ−８４０２（膜厚：２３ミクロン）を用いて実施例１に対する比較試験を行った。この接着フィルムは、エポキシ樹脂とイミダゾール系混合物系であり、ＤＳＣ測定での反応開始温度は９０℃、硬化反応の６０％が終了する温度は１７０℃であった。
このフィルムを用いて、金バンプ（面積：５０×５０μｍ、スペース２０μｍ、高さ：１５μｍ、バンプ数３６２）付きチップ（１．７×１７ｍｍ、厚み：５００μｍ）とＩＴＯ回路付きガラス基板（厚み：１．１ｍｍ）の接続を、以下に示すように行った。異方導電フィルム（２×２０ｍｍ）をＩＴＯ回路付きガラス基板に８０℃、０．９８ＭＰａ（１０ｋｇｆ／ｃｍ^２）で貼り付けた後、セパレータを剥離し、チップのバンプとＩＴＯ回路付きガラス基板の位置合わせを行った。次いで、１次条件が１５０℃、４０ｇ／バンプ、１秒でかつ２次条件が２００℃、４０ｇ／バンプ、１秒である２段階の接続条件でチップ上方から加熱、加圧を行い、本接続を行った。本接続後の接続抵抗は、１バンプあたり最高で８Ω、平均で２Ω、絶縁抵抗は１０^８Ω以上であり、これらの値は−４０〜１００℃の熱衝撃試験１０００サイクル処理、高温・高湿（８５℃／８５％ＲＨ、１０００ｈ）試験後において接続抵抗値が５０Ω以上となり２段階の接続条件では異常を示した。
【００１８】
（比較例３）
比較例２で使用した二層構成異方導電フィルムＡＣ−８４０２（膜厚：２３ミクロン）を用い、金バンプ（面積：５０×５０μｍ、スペース２０μｍ、高さ：１５μｍ、バンプ数３６２）付きチップ（１．７×１７ｍｍ、厚み：５００μｍ）とＩＴＯ回路付きガラス基板（厚み：１．１ｍｍ）の接続を、以下に示すように行った。異方導電フィルム（２×２０ｍｍ）をＩＴＯ回路付きガラス基板に８０℃、０．９８ＭＰａ（１０ｋｇｆ／ｃｍ^２）で貼り付けた後、セパレータを剥離し、チップのバンプとＩＴＯ回路付きガラス基板の位置合わせを行った。次いで、２５０℃、４０ｇ／バンプ、２秒の接続条件でチップ上方から加熱、加圧を行い、本接続を行った。本接続後の接続抵抗は、１バンプあたり最高で１Ω、平均で３００ｍΩ、絶縁抵抗は１０^８Ω以上であり、これらの値は−４０〜１００℃の熱衝撃試験１０００サイクル処理、高温・高湿（８５℃／８５％ＲＨ、１０００ｈ）試験後において、接続抵抗値が５０Ω以上となり異常を示した。
【００１９】
【発明の効果】
本発明の回路接続用接着フィルム及びこれを用いた接続方法によれば、３秒以下の短時間接続を可能にすることができ、回路基板同士またはＩＣチップ等の電子部品と配線基板の接続において生産性を向上することができる。また、接続温度を２２０℃以下とすることにより、熱膨張率差に基づく内部応力を低下することができ、信頼性試験後においても接続部での接続抵抗の増大や接着剤の剥離がなく、接続信頼性が向上する。
したがって、本発明の接着フィルムは、ＬＣＤパネルとＴＡＢ、ＴＡＢとプリント基板、ＬＣＤパネルとＩＣチップ、ＩＣチップとプリント基板とを接続時の加圧方向にのみ電気的に接続するために好適に用いられる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of connecting an adhesive film for circuit connection used for connecting circuit boards to each other or an electronic component such as an IC chip and a wiring board, and an adhesive film for circuit connection used therefor.
[0002]
[Prior art]
BACKGROUND When electrically connecting circuit boards to each other or an electronic component such as an IC chip to a circuit board, an adhesive or an anisotropic conductive adhesive in which conductive particles are dispersed is used. That is, electrical connection can be achieved by disposing these adhesives between the opposing electrodes, connecting the electrodes by heating and pressing, and then imparting conductivity in the pressing direction. For example, JP-A-3-16147 proposes an adhesive for circuit connection based on an epoxy resin.
[0003]
[Patent Document 1]
JP 03-016147 A
[Problems to be solved by the invention]
However, the heating and pressurizing time performed using a conventional adhesive for connecting a circuit such as an epoxy resin and an imidazole-based mixture is 170 ° C. to 230 ° C., about 20 seconds to 4 seconds, and a short connection time of 3 seconds or less. In order to make this possible, high-temperature heating of 230 ° C. or more is required. At this time, when the IC chip is directly mounted on the substrate via an adhesive, a printed circuit board using an FR-4 substrate or the like as a connection substrate, or a flexible wiring board using a polymer film such as polyimide or polyester as a substrate Or, if a glass substrate is used, after connection, there is a problem that the warp of the chip and the substrate increases due to internal stress based on a difference in coefficient of thermal expansion with the chip, the connection resistance increases at the connection portion, and the adhesive is peeled off. is there.
In addition, by using a highly reactive latent curing agent such as a sulfonium salt, the heating temperature can be set to 230 ° C. or lower. However, at a heating temperature of 180 ° C. or higher, the curing reaction proceeds rapidly. However, there is a problem that the resin flow becomes insufficient and the electrical conductivity decreases.
In view of the above problems, the present invention provides a method for connecting an adhesive film for circuit connection, which can electrically connect circuit electrodes at a low temperature and in a short time, and an adhesive film for circuit connection used therefor.
[0005]
[Means for Solving the Problems]
In the method for connecting the adhesive film for circuit connection of the present invention, the heating and pressurizing time during connection is 3 seconds or less, and the primary conditions of the heating and pressurizing time are 120 ° C to 180 ° C and 2 seconds or less, and The secondary condition is a two-stage connection condition in which the secondary condition is 180 ° C. to 220 ° C. for 1 second or more. The adhesive film for circuit connection contains a reactive resin that is cured by heat, and the exothermic onset temperature of the adhesive by differential scanning calorimetry (DSC) is 60 ° C. or more and 60% of the curing reaction is completed. Temperature is 160 ° C. or less. As the reactive resin, a resin in which an epoxy resin and a latent curing agent are formed of a sulfonium salt is preferably used. Furthermore, 0.1 to 30% by volume of conductive particles can be dispersed in these adhesives.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, the heating and pressurizing time during connection is 3 seconds or less, and the primary condition of the heating and pressurizing time is 120 ° C to 180 ° C, 2 seconds or less, and the secondary condition is 180 ° C to 220 ° C. A method for connecting an adhesive film for circuit connection, wherein a two-stage connection condition of 1 second or longer is used. The adhesive film for circuit connection contains a reactive resin that is cured by heat, and the temperature at which the adhesive starts to generate heat in DSC at 60 ° C. or higher and the temperature at which 60% of the curing reaction ends is 160 ° C. or lower. It is preferable that The reactivity of the adhesive film can be measured by DSC (heating rate: 10 ° C./min).
[0007]
As the reactive resin, in addition to a mixture of an epoxy resin and a latent curing agent of a sulfonium salt, a mixture of a radical reactive resin and an organic peroxide is used.
In particular, the sulfonium salt is preferably used at a temperature of 60 ° C. or higher and a temperature at which 60% of the curing reaction is completed is 160 ° C. or lower, and has a long pot life while having excellent low-temperature reactivity. As the sulfonium salt, a sulfonium salt represented by the general formula (1) is preferably used.
[0008]
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In the general formula (1), R ¹ is an electron-withdrawing group, for example, a nitroso group, a carbonyl group, a carboxyl group, a cyano group, a trialkylammonium group, a fluoromethyl group, and R ² and R ³ are electron-donating groups. group, for example, an amino group, a hydroxyl group, a methyl group, Y ^- is a non-nucleophilic anions for example, hexafluoroarsenate, and hexafluoroantimonate.
[0009]
The amount of the sulfonium salt to be mixed with 100 parts by weight of the epoxy resin is preferably 1 to 20 parts by weight. In this case, two exothermic peaks may appear due to DSC. DSC is based on a zero-point method of supplying or removing a calorific value so as to constantly cancel out a temperature difference between a standard sample having no heat generation and heat absorption within a measurement temperature range, and a commercially available measuring device is used. Can be used to measure. The reaction of the adhesive is an exothermic reaction, and when the sample is heated at a constant heating rate, the sample reacts to generate heat. The calorific value is output on a chart, and the area surrounded by the calorific curve and the base line is determined based on the base line, and this is defined as the calorific value. The temperature is measured from room temperature (25 ° C.) to about 300 ° C. at a rate of 10 ° C./min, and the above-mentioned calorific value is determined. These measures are performed fully automatically, and can be easily performed by using them. The temperature at which the curing reaction ends at 60% (60% of the calorific value) and 80% (80% of the calorific value) can be obtained from the area of the calorific value, and is the temperature at that time.
[0010]
Examples of the epoxy resin used in the present invention include a bisphenol-type epoxy resin derived from epichlorohydrin and bisphenol A or F, AD, an epoxy novolak resin derived from epichlorohydrin and phenol novolak or cresol novolak, or a skeleton containing a naphthalene ring. It is possible to use various epoxy compounds having two or more glycidyl groups in one molecule such as naphthalene epoxy resin, glycidylamine, glycidyl ether, biphenyl, alicyclic, etc., alone or as a mixture of two or more. It is possible. For these epoxy resins, it is preferable to use high-purity products 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.
[0011]
In addition, a thermoplastic resin such as a phenoxy resin, a polyester resin, or a polyamide resin may be added to the adhesive film for circuit connection in order to make the film formability easier. These film-forming polymers are effective in relaxing stress during curing of the reactive resin. In particular, it is more preferable that the film-forming polymer has a functional group such as a hydroxyl group because the adhesiveness is improved. Film formation is performed by dissolving or dispersing an adhesive composition comprising at least a reactive resin and a latent curing agent in an organic solvent, liquefying the composition, applying the composition on a releasable substrate, and removing the solvent at or below the activation temperature of the curing agent. This is done by removing. As the solvent used at this time, a mixed solvent of an aromatic hydrocarbon type and an oxygen-containing type is preferable because the solubility of the material is improved.
[0012]
The adhesive for circuit connection of the present invention may be mixed and dispersed with conductive particles for the purpose of positively imparting anisotropic conductivity in order to absorb variations in the height of chip bumps and substrate electrodes. In the present invention, the conductive particles are, for example, metal particles such as Au, Ag, Cu, and solder, and are formed by providing a conductive layer of Ni, Cu, Au, solder, or the like on a polymer spherical core material such as polystyrene. More preferred. Further, a surface layer of Su, Au, solder, or the like can be formed on the surface of the conductive particles. The particle size needs to be smaller than the minimum distance between the electrodes of the substrate, and if there is a variation in the height of the electrodes, it is preferably larger than the variation in height, and preferably 1 to 10 μm. The amount of the conductive particles dispersed in the adhesive is 0.1 to 30% by volume, preferably 0.2 to 15% by volume.
[0013]
In the adhesive for circuit connection of the present invention, an inorganic filler or rubber-like particles can be mixed and dispersed.
The inorganic filler is not particularly limited, and examples thereof include powders of fused silica, crystalline silica, calcium silicate, alumina, calcium carbonate and the like. The amount of the inorganic filler is preferably 10 to 200 parts by weight based on 100 parts by weight of the adhesive resin composition. The larger the amount, the more effective the lowering of the coefficient of thermal expansion. Insufficiency in conductivity due to a decrease in the adhesiveness and the removability of the adhesive at the connection portion occurs, and the thermal expansion coefficient cannot be sufficiently reduced if the amount is small, so that the content is more preferably 20 to 90 parts by weight. Further, the average particle size is preferably 3 μm or less for the purpose of preventing poor conduction at the connection portion. In addition, it is desirable to use a spherical filler for the purpose of preventing a decrease in fluidity of the resin at the time of connection and a damage of the passivation film of the chip. The inorganic filler can be mixed and dispersed together with the conductive particles or in a layer where the conductive particles are not used.
[0014]
The rubber particles dispersed in the adhesive are not particularly limited as long as the rubber particles have a glass transition temperature of 25 ° C. or lower, butadiene rubber, acrylic rubber, styrene-butadiene-styrene rubber, nitrile-butadiene rubber, silicone Rubber and the like can be used, and those having an average particle size of 0.1 to 10 μm are used, and rubber particles having an average particle size of not more than 80% of the particle size distribution are particularly preferable, and more preferably 0%. .1 to 5 μm are used. It is more preferable that the surface of the fine particles is treated with a silane coupling agent because the dispersibility in the reactive resin is improved.
Among rubber particles, silicone rubber particles are excellent in solvent resistance and also excellent in dispersibility, so that they can be used as effective rubber particles. Silicone rubber particles can be hydrolyzed and polycondensed by adding a silane compound or methyl trialkoxysilane and / or a partially hydrolyzed condensate thereof to an aqueous alcohol solution adjusted to pH> 9 with a basic substance such as caustic soda or ammonia. It can be obtained by copolymerization of an organosiloxane. Further, silicone fine particles containing a functional group such as a hydroxyl group, an epoxy group, a ketimine, a carboxyl group, or a mercapto group at a molecular terminal or a molecular inner chain are preferable because dispersibility in a reactive resin is improved.
[0015]
【Example】
(Example 1)
50 g of a phenoxy resin (manufactured by Union Carbide, PKHC) was dissolved in 115 g of ethyl acetate to obtain a 30% by weight solution.
60 g of a phenoxy resin in a solid weight ratio, 30 g of a bisphenol A type epoxy resin (epoxy equivalent: 180) in which acrylic particles having an average particle diameter of 0.2 μm are dispersed at 20 wt%, 5 g of a bisphenol A type solid epoxy resin (epoxy equivalent: 470), p -Acetoxyphenylbenzylmethylsulfonium salt (non-nucleophilic anion: hexafluoroantimonate) 3 g is blended, and conductive particles in which an Au layer is formed on the surface of a polystyrene-based nucleus (diameter: 3 µm) are mixed and dispersed at 10% by volume. Thus, a film coating solution was obtained. Next, this solution was applied to a 50 μm-thick PET film having one surface subjected to surface treatment using a coating apparatus, and dried with hot air at 70 ° C. for 10 minutes to obtain a film-like adhesive a having an adhesive layer thickness of 10 μm. Was.
Then, in the preparation of the film coating solution, a film coating solution prepared in the same manner except that the conductive particles having the Au layer formed thereon were not dispersed, to a PET film having a 50 μm-thick surface treated on one side. It was applied using a coating device, and dried with hot air at 70 ° C. for 10 minutes to obtain a film adhesive b having an adhesive layer thickness of 15 μm. Further, while heating the obtained film adhesives a and b at 40 ° C., a two-layer anisotropic conductive film laminated by a roll laminator was produced. The reaction start temperature in DSC measurement of this adhesive film was 80 ° C., and the temperature at which 60% of the curing reaction was completed was 150 ° C.
Next, using the prepared anisotropic conductive film, a chip (1.7 × 17 mm, thickness: 500 μm) with a gold bump (area: 50 × 50 μm, space: 20 μm, height: 15 μm, number of bumps: 362) and an ITO circuit The connection of the attached glass substrate (thickness: 1.1 mm) was performed as shown below. After attaching an anisotropic conductive film (2 × 20 mm) to a glass substrate with an ITO circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ), the separator is peeled off, and chip bumps and the position of the glass substrate with the ITO circuit are removed. Matching was performed. Next, heating and pressurization are performed from above the chip under two-stage connection conditions in which the primary condition is 150 ° C., 40 g / bump, 1 second, and the secondary condition is 200 ° C., 40 g / bump, 1 second. Was done. The connection resistance after this connection is 50 mΩ at the maximum per bump, 20 mΩ on average, and the insulation resistance is 10 ⁸ Ω or more. These values are 1000 cycles of thermal shock test at -40 to 100 ° C. (85 ° C./85% RH, 1000 h) There was no change even after the test, showing good connection reliability.
[0016]
(Comparative Example 1)
Chip (1.7 × 17 mm, thickness: 500 μm) with gold bumps (area: 50 × 50 μm, space: 20 μm, height: 15 μm, number of bumps: 362) using the two-layer anisotropic conductive film prepared in Example 1. And a glass substrate with an ITO circuit (thickness: 1.1 mm) were connected as shown below. After attaching an anisotropic conductive film (2 × 20 mm) to a glass substrate with an ITO circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ), the separator is peeled off, and chip bumps and the position of the glass substrate with the ITO circuit are removed. Matching was performed. Then, heating and pressurization were performed from above the chip under the connection conditions of 200 ° C., 40 g / bump, and 2 seconds, and the main connection was performed. The connection resistance after this connection is 10Ω at the maximum per bump, 2Ω on average, and the insulation resistance is 10 ⁸ Ω or more. These values are 1000 cycles of thermal shock test at -40 to 100 ° C, high temperature and high humidity. (85 ° C./85% RH, 1000 h) After the test, the connection resistance value became 50Ω or more, indicating an abnormality.
[0017]
(Comparative Example 2)
A comparative test to Example 1 was performed using an anisotropic conductive film AC-8402 (thickness: 23 microns) manufactured by Hitachi Chemical Co., Ltd. This adhesive film was a mixture of an epoxy resin and an imidazole-based material, and had a reaction initiation temperature of 90 ° C. in DSC measurement and a temperature of 170 ° C. at which 60% of the curing reaction was completed.
Using this film, a chip (1.7 × 17 mm, thickness: 500 μm) with gold bumps (area: 50 × 50 μm, space: 20 μm, height: 15 μm, bump number: 362) and a glass substrate with an ITO circuit (thickness: 1) .1 mm) as described below. After attaching an anisotropic conductive film (2 × 20 mm) to a glass substrate with an ITO circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ), the separator is peeled off, and chip bumps and the position of the glass substrate with the ITO circuit are removed. Matching was performed. Next, heating and pressurization are performed from above the chip under two-stage connection conditions in which the primary condition is 150 ° C., 40 g / bump, 1 second, and the secondary condition is 200 ° C., 40 g / bump, 1 second. Was done. The connection resistance after this connection is a maximum of 8Ω per bump, an average of 2Ω and an insulation resistance of 10 ⁸ Ω or more. These values are 1000 cycles of thermal shock test at −40 to 100 ° C., high temperature and high humidity. (85 ° C./85% RH, 1000 h) After the test, the connection resistance value became 50Ω or more, and abnormalities were shown under the two-stage connection condition.
[0018]
(Comparative Example 3)
Using the two-layer anisotropic conductive film AC-8402 (thickness: 23 μm) used in Comparative Example 2, a chip with gold bumps (area: 50 × 50 μm, space: 20 μm, height: 15 μm, bump number: 362) ( (1.7 × 17 mm, thickness: 500 μm) and a glass substrate with an ITO circuit (thickness: 1.1 mm) were connected as shown below. After attaching an anisotropic conductive film (2 × 20 mm) to a glass substrate with an ITO circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ), the separator is peeled off, and chip bumps and the position of the glass substrate with the ITO circuit are removed. Matching was performed. Next, heating and pressurization were performed from above the chip under the connection conditions of 250 ° C., 40 g / bump, and 2 seconds, and the main connection was performed. The connection resistance after this connection is 1 Ω at maximum per bump, 300 mΩ on average, and the insulation resistance is 10 ⁸ Ω or more. These values are 1000 cycles of thermal shock test at −40 to 100 ° C., high temperature and high humidity. (85 ° C./85% RH, 1000 h) After the test, the connection resistance value became 50Ω or more, indicating an abnormality.
[0019]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the adhesive film for circuit connection of this invention and the connection method using the same, it is possible to enable short-time connection of 3 seconds or less, and to connect electronic parts such as circuit boards or electronic parts such as IC chips to a wiring board. Productivity can be improved. Further, by setting the connection temperature to 220 ° C. or lower, the internal stress based on the difference in the coefficient of thermal expansion can be reduced, and even after the reliability test, there is no increase in connection resistance or peeling of the adhesive at the connection portion, Connection reliability is improved.
Therefore, the adhesive film of the present invention is preferably used for electrically connecting the LCD panel to the TAB, the TAB to the printed board, the LCD panel to the IC chip, and the IC chip to the printed board only in the pressing direction at the time of connection. Can be

Claims (4)

The heating and pressurizing time at the time of connection is less than 3 seconds in the heat-adhesive adhesive film for electrically connecting the electrodes in the pressurizing direction by heating and pressing the opposing circuit electrodes. A bonding method for circuit connection, wherein the primary condition of the pressure time is 120 ° C. to 180 ° C. for 2 seconds or less and the secondary condition is 180 ° C. to 220 ° C. for one second or more. How to connect the film. A temperature at which the adhesive film for circuit connection contains a reactive resin which is cured by heat, the exothermic start temperature of the adhesive film by differential scanning calorimetry (DSC) is 60 ° C. or more and 60% of the curing reaction is completed. Is 160 ° C. or lower, the adhesive film for circuit connection used in the method for connecting an adhesive film for circuit connection according to claim 1. The adhesive film for circuit connection according to claim 2, wherein the reactive resin comprises an epoxy resin and the latent curing agent comprises a sulfonium salt. The adhesive film for circuit connection according to claim 2 or 3, wherein 0.1 to 30% by volume of conductive particles is dispersed in the adhesive film for circuit connection.