JP4524727B2 - Ni alloy grain for anisotropic conductive film and method for producing the same - Google Patents
Ni alloy grain for anisotropic conductive film and method for producing the same Download PDFInfo
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【０００１】
【発明の属する技術分野】
本発明は、異方性導電膜に用いられる異方性導電膜用Ｎｉ合金粒およびその製造方法に関するものである。
【０００２】
【従来の技術】
異方性導電膜は主にパーソナルコンピュータ、携帯通信機器等のエレクトロニクス製品において液晶ディスプレイ、有機ＥＬディスプレイ等の表示ディスプレイと半導体及び基板の電気的接続及び基板同士の電気的接続に用いられている。
従来、この異方性導電膜に用いられる導通粒子には樹脂球に金属めっき処理を行った球が用いられてきた。さらに、最近では接続時の電気抵抗を小さくするために、導通粒子としてＮｉ、Ｃｕ、Ａｕ、Ａｇおよびそれぞれの合金粉末を用いるという提案もされてきた。その中でも、Ｎｉおよびその合金粉末を用いることが良いとされてきた。
【０００３】
上述した導通粒子について、樹脂球に金属めっき処理を行った球を用いた場合、高価となるだけでなく、樹脂球は硬さが低くマトリクスの樹脂を砕くだけの硬さが不足し、しかも樹脂球自体が絶縁体であるために導電部が少なく、導通が良好でないという問題点があった。
そして、これらの欠点を解決するために導通粒子としてＮｉ、Ｃｕ、Ａｕ、Ａｇおよびそれぞれの合金粉末を用いることが例えば特開平８−２７３４４０号に提案された。
【０００４】
上述の特開平８−２７３４４０号に示される導通粒子のＡｕは高価であること、Ａｇはマイグレーションを発生させること、Ｃｕは容易に酸化するために導通が良好でなくなるという欠点を有し、更にＮｉは酸化され易く、しかも硬くて変形し難いため接点が不安定になるとして、表面の耐酸化性に優れ、且つマイグレーションを抑制する理由によりガスアトマイズ法にて製造したＣｕとＡｇとの合金粉末が最良であるとしている。
しかしながら、ガスアトマイズ法で得られる合金粉末は粒径が比較的大きいものであり、例えば１０μｍ以下の合金粉末を得ようとすると歩留まりが極めて低く、経済的ではないばかりか、やはりＣｕやＡｇの欠点である、表面酸化やマイグレーションの発生の危険がある。
【０００５】
【発明が解決しようとする課題】
ところで、異方性導電膜で確実に導通をとれるようにするには、導電粒子の硬度を低くして導電粒子の変形により電極との接触面積を広くする方法と、導電粒子の硬度を高め、電極表面に形成された酸化膜を確実に破壊する方法の二通りの方法があり、上述の特開平８−２７３４４０号に提案されるものは前者の思想に基づくものである。
そこで、本発明者等は導電粒子の硬さを高める方法について鋭意検討を行い、用いた導電粒子はマイグレーション発生の危険性が少ないＮｉにて行ってみたところ、単純なＮｉの導電粒子は特開平８−２７３４４０号に記載される通り、酸化され易く、接触面積を広くするに必要な硬さでもなく、しかも、電極表面の酸化膜を確実に突き破るに必要な硬さが不充分で、導通が不安定になることを確認した。
【０００６】
そこで、本発明者等はＮｉの高硬度化を図るために、種々の合金元素との合金化と、同時にアトマイズ法では得にくい１０μｍ以下の導電粒子を効率良く、しかも均一な大きさの導電粒子が得られる方法を検討した結果、高硬度化に必要な合金元素としては、半金属元素が有効であること、アトマイズ法では得にくい例えば１０μｍ以下の小さく、均一な粒径のＮｉ合金粒は無電解還元法を用いれば良いこと、しかも、この方法で得られるＮｉ合金粒は実質的に非晶質化されたＮｉ合金粒は高硬度とすることができ、粉末自体の粒径を小さくすることは可能となったが、電極の酸化膜を確実に突き破るに必要な硬さに付いては更に高硬度化を図る必要があり、しかも、実質的に非晶質の合金では電気抵抗が高く、異方性導電膜用粉末として使用が困難であるという問題が発生した。
本発明の目的は、異方性導電膜において電極に接触時の導通がよい異方性導電膜用Ｎｉ合金粒およびその製造方法を提供するものである。
【０００７】
【課題を解決するための手段】
本発明者は、上記問題について検討した結果、異方性導電膜用粉末として無電解還元法によって微細な実質的に非晶質Ｎｉ合金粒を作製した後に加熱処理を行うことで、組織中にＮｉの金属間化合物相を析出させて高硬度化を達成すると同時に、電気抵抗をも改善できることを見出し本発明に到達した。
【０００８】
すなわち本発明は、Ｎｉと半金属であるＰまたはＢと、残部不可避的不純物で構成され、結晶質のＮｉ合金粒であって、組織中にＮｉの金属間化合物相が析出してなることを特徴とする異方性導電膜用Ｎｉ合金粒である。
また、本発明の異方性導電膜用Ｎｉ合金粒は粒径のｄ９０値（積算分布曲線において全体の９０ｖｏｌ％を示す粉末の粒径）が１０μｍ以下で、球状であることが好ましく、更に好ましくは、上述の異方性導電膜用Ｎｉ合金粒の表面がＡｕで被覆されている異方性導電膜用Ｎｉ合金粒である。
【０００９】
また本発明は、上述の異方性導電膜用Ｎｉ合金粒の製造方法において、前記異方性導電膜用Ｎｉ合金粒は、りん酸系水溶液または硼酸系水溶液を用いた無電解還元法によって作製した非晶質Ｎｉ合金粒子を少なくとも結晶化とＮｉの金属間化合物を析出させる加熱処理することにより作製する異方性導電膜用Ｎｉ合金粒の製造方法である。
好ましくは、無電解還元法によって作製した非晶質Ｎｉ合金粒子を、解砕処理した後に前記加熱処理を行い作製する異方性導電膜用Ｎｉ合金粒の製造方法であり、更に好ましくは、前記加熱処理後の異方性導電膜用Ｎｉ合金粒にＡｕを被覆処理する異方性導電膜用Ｎｉ合金粒の製造方法である。
【００１０】
【発明の実施の形態】
上述したように本発明の重要な特徴は、異方性導電膜用の導通粒子として実質的にＮｉと半金属で構成され、結晶化したＮｉ合金粒であって、組織中にＮｉの金属間化合物相が析出した異方性導電膜用Ｎｉ合金粒にある。
以下に本発明を詳しく説明する。
先ず、本発明の異方性導電膜用Ｎｉ合金粒は、実質的にＮｉと半金属とで構成され、結晶化した金属組織を有する。
本発明の異方性導電膜用Ｎｉ合金粒は、実質的に非晶質であるＮｉ合金粒を結晶化したものであり、実質的に非晶質の合金である場合には伝導電子と局在モーメントの変換相互作用によるｋｏｎｄｏ効果により電気抵抗率が上昇して導通性が悪化するが、これを結晶化することにより上記が解消されて電気抵抗率が低下し、導通性が良好となる。
尚、本発明でいう実質的に非晶質とは図２(ａ)に示す様にＮｉ核のピークがブロードに検出される様な状態を言う。
【００１１】
また、本発明で言う半金属とは、Ｃ、Ｂ、Ｐ、Ｓｉ、Ａｓ、Ｔｅ、Ｇｅ、Ｓｂ等の元素を指し、これら半金属は非晶質化と、硬さを高める効果とを有し本発明では必須の元素であるが、この内、本発明に好適な半金属は、Ｎｉとの金属間化合物を形成可能な、Ｃ、Ｂ、Ｐである。
中でもＰは、合金粉末を容易に球状化する作用を持つだけでなく、加熱処理による結晶化にて、微細なＮｉ３Ｐからなる金属間化合物を析出させて非常に硬い粒を得ることが可能となる。
また、ＢもＰと同様な作用効果を有し、Ｂの場合はＮｉ３Ｂの金属間化合物相を析出させることができる。
なお、本発明では実質的にＮｉと半金属とで構成されると規定しているが、本発明で言う実質的とは、Ｎｉと半金属以外に、製造上不可避的に含有されるものを含むことは言うまでもない。
【００１２】
また、本発明の異方性導電膜用Ｎｉ合金粒は、その粒径のｄ９０値が１０μｍ以下の球状であることが好ましく、粒径のｄ９０値を１０μｍ以下とすることにより、異方性導電膜用Ｎｉ合金粒同士が接触する割合が少なくなり、狭ピッチ接続で隣り合う電極間の絶縁性の信頼性が向上してショートする可能性が低くなり、更に電極間での絶縁性を上昇させることが可能となるだけでなく、異方性導電膜の厚さを薄くすることが可能となり、ファインピッチ化させた実装にも十分に対応することが可能となる。
この時、この異方性導電膜用Ｎｉ合金粒の粒径のｄ９０値を５μｍ以下にすると異方性導電膜の厚さをさらに薄くし、ファインピッチ化させることができるためにより好ましいが、過剰に粒径が小さくなり過ぎると、逆に異方性導電膜用Ｎｉ合金粒同士が接触してショートして異方性導電膜用の金属粒として不適当となるため、好ましいｄ９０値の下限としては２μｍであれば良い。
なおｄ９０値とは、積算分布曲線において９０ｖｏｌ％を示す粉末の粒径である。
【００１３】
また、本発明のＮｉ合金粒が球状であれば、表面積が広くなって導通の信頼性が向上するので、この球状の異方性導電膜用Ｎｉ合金粒が、上述した粒径のｄ９０値を１０μｍ以下であることを満足することにより、多数の粉末で接触することが可能となり、確実に良好な導通を得ることが可能となる。
なお、本発明で言う球状とは、真球状のものは当然のこと、例えば図４に示すような楕円形状、或は1μｍ以下の微細球状粒が付着しているもの、球体に多少の出っ張りや窪みがあっても球状と定義する。
【００１４】
以上、説明する本発明の異方性導電膜用Ｎｉ合金粒は以下の方法で製造することができる。
先ず、本発明では無電解還元法により、異方性導電膜用Ｎｉ合金粒となる実質的に非晶質のＮｉ合金粒を得る。この実質的に非晶質のＮｉ合金粒とすることで、一旦高硬度化することができる。
この実質的に非晶質のＮｉ合金粒は、基相となるＮｉは標準電極電位が低いために無電解還元法による粉末作製が容易であること、更に容易にＮｉ及びＰ等の半金属とを実質的に非晶質状態で得ることができること、及び異方性がないために球状化させたＮｉ合金粒を得ることができると言う三つの利点があるため、本発明では無電解還元法を用いる。
具体的な製法としては、水酸化ナトリウム水溶液にりん酸系水溶液を混合し、それにニッケル系塩を混合させる湿式無電解法により非晶質のＮｉ−Ｐ合金粒子が得ることができ、りん酸系水溶液の代わりに硼酸系水溶液を用いてＮｉ−Ｂ合金粒子を作製することも可能である。
なお、この時、りん酸系水溶液の量を調整することにより、得られるＮｉ合金粉末の大きさを調整することも可能である。
【００１５】
上記したＮｉ合金粒は湿式無電解法によって作製したものをそのまま加熱処理して異方性導電膜用Ｎｉ合金粒として使用してもよいが、異方性導電膜用粒子として使用される時に粒子が凝集した状態では導通をとる場合に粒子同士の接触による絶縁抵抗が高くなってしまうために、Ｎｉ合金粒は解砕処理を行って単粒子化されることが望ましく、解砕処理を行うことで、得られるＮｉ合金粒の粒径を均一にすることも可能である。
単粒子化の処理としてはジェットミル等および風力分級機等によっても行うことが可能であるし、更にはその双方を用いることによって行うことも可能である。
【００１６】
次に本発明では上述した実質的に非晶質のＮｉ合金粒を作製した後に加熱処理することで結晶化し、微細な組織を有して、しかも、実質的に非晶質の状態より更に高硬度化した異方性導電膜用Ｎｉ合金粒を得ることができ、確実に電極表面の酸化膜を破壊す硬さと、優れた電気抵抗の両立を図ることができる。
なお、この時の加熱温度と時間は、結晶化とＮｉの金属間化合物が析出可能な温度と時間を満たせば良いが、好ましくは、３５０℃〜４５０℃の間で数十分〜数時間の加熱処理を行うと良い。この加熱処理によって例えば、Ｎｉ３ＰやＮｉ３Ｂが析出した１０μｍ以下の微細な粒径を有する異方性導電膜用Ｎｉ合金粒を得ることができる。
【００１７】
また本発明では、上記の加熱処理したままの異方性導電膜用Ｎｉ合金粒をそのままでも使用することが可能であるが、得られた異方性導電膜用Ｎｉ合金粒の表面にＡｕを被覆処理することにより、導通をとる場合の接触抵抗をより低くすることができる。
被覆処理の層としては１μｍ以下であれば十分に接触抵抗を低くすることができ、具体的にはメッキ処理にてメッキ層を形成すれば良い。
【００１８】
【実施例】
以下に本発明例・比較例を挙げて本発明を詳細に説明する。本発明はその範囲を超えない限り、以下の実施例に限定されるものではない。
【００１９】
（実施例１）
水酸化ナトリウム水溶液０．６（ｍｏｌ／ｌ）を１０（ｌ）、次りん酸ナトリウム水溶液１．８（ｍｏｌ／ｌ）を１０（ｌ）の双方を十分に混合させた後に８０℃の温度に加熱保持し、塩化ニッケル０．６（ｍｏｌ／ｌ）、１０（ｌ）を投入したところ、反応が起って微細粒が生成された。
この粉末を漉して取り出して構造をエックス線回折によって確認したところ図２(ａ)に示す様に実質的に非晶質であることが確認された。
その後、ジェットミルにて解砕を行い、レーザ回折法にて粒径を測定したところｄ９０値が４．２μｍであり、図４に示す球状のＮｉＰ合金粒を得た。その後に４００℃にて加熱処理を行い、図２(ｂ)に示す様にＮｉ相とＮｉ３Ｐ相が微細に析出した異方性導電膜用Ｎｉ合金粒を作製した。
なお、図２(ａ)および図２(ｂ)に示される合金粒の断面を電子顕微鏡によって観察したところ、図３(ａ)では中心にＮｉの核を有した非晶質層が観察され、図３(ｂ)には微細に析出したＮｉ３Ｐが観察された。
【００２０】
次に、上記の異方性導電膜用Ｎｉ合金粒の重量部１とし、ビスフェノール系熱硬化樹脂２５重量部、イミダゾール系硬化剤２重量部を加えて厚さ２０μｍの組成物を作製した。得られた組成物（５）には図１（ａ）に示すように異方性導電膜用Ｎｉ合金粒（４）が分散しているものである。この組成物をＴＣＰ(Ｔａｐｅ Ｃａｒｒｉｅｒ Ｐａｃｋａｇｅ)（１）に設けられた電極（３）と、樹脂基板（２）に設けられた電極（３）との間にはさみ１７０℃、３ＭＰａの条件にて２０秒間で接続させた。この状態を図１（ｂ）として示す。
次に、温度６０℃、湿度９０％に前記試作品を保持して前記試作品の接続の良好性を調査する高温高湿耐久試験を行ったところ、保持時間が５００時間後において接続抵抗が１８Ωと十分に低い値を示した。また、絶縁抵抗を測定したところ１×１０９以上と十分に高い値を示した。
【００２１】
（実施例２）
水酸化ナトリウム水溶液０．６（ｍｏｌ／ｌ）を１０（ｌ）、次りん酸ナトリウム水溶液２．４（ｍｏｌ／ｌ）を１０（ｌ）の双方を十分に混合させた後に６０℃の温度に加熱保持し、塩化ニッケル０．６（ｍｏｌ／ｌ）、１０（ｌ）を投入したところ、反応が起って微細粒が生成された。
このＮｉ合金粒を漉して取り出して構造をエックス線回折によって確認したところ実質的に非晶質であることが確認された。その後、ジェットミルにて解砕処理を行い、実施例１と同じ方法で粒径を測定したところｄ９０値が３．１μｍであった。その後に４００℃にて加熱処理を行い、Ｎｉ相とＮｉ３Ｐ相が微細に析出した異方性導電膜用Ｎｉ合金粒を作製した。
この粉末をさらに５％塩酸で酸処理した後に無電解Ａｕめっきを３０分行い、水洗してめっき層を確認したところ０．５μｍであることを確認した。
【００２２】
上記の異方性導電膜用Ｎｉ合金粒の重量部１とし、ビスフェノール系熱硬化樹脂２５重量部、イミダゾール系硬化剤２重量部を加えて厚さ２０μｍの組成物を作製した。得られた組成物（５）には図１（ａ）に示すように異方性導電膜用Ｎｉ合金粒（４）が分散しているものである。この組成物をＴＣＰ（１）に設けられた電極（３）と、樹脂基板（２）に設けられた電極（３）との間にはさみ１７０℃、３ＭＰａの条件にて２０秒間で接続させた。この状態を図１（ｂ）として示す。
次に、前記と同様の温度６０℃、湿度９０％の高温高湿耐久試を行い、５００時間保持した後の接続抵抗を測定したところ８Ωと十分に低い値を示した。また、絶縁抵抗を測定したところ１×１０９以上と十分に高い値を示した。
【００２３】
（比較例）
水酸化ナトリウム水溶液０．６（ｍｏｌ／ｌ）を１０（ｌ）、次りん酸ナトリウム水溶液２．４（ｍｏｌ／ｌ）を１０（ｌ）の双方を十分に混合させた後に７０℃の温度に加熱保持し、塩化ニッケル０．６（ｍｏｌ／ｌ）、１０（ｌ）を投入したところ、反応が起って微細粒が生成された。この粉末を漉して取り出して構造をエックス線回折によって確認したところ実質的に非晶質であることが確認された。その後、ジェットミルにて解砕を行って実質的に非晶質Ｎｉ合金粒を作製した。実施例１と同じ方法で粒径を測定したところｄ９０値が２．９μｍであった。
【００２４】
実質的に非晶質Ｎｉ合金粒を異方性導電膜用Ｎｉ合金粒として重量部１とし、ビスフェノール系熱硬化樹脂２５重量部、イミダゾール系硬化剤２重量部を加えて厚さ２０μｍの組成物を作製した。得られた組成物を図１(a)、(b)に示すようにＴＣＰおよび樹脂基板の間にはさみ１７０℃、３ＭＰａの条件にて２０秒間で接続させた。
次に、前記と同様の温度６０℃、湿度９０％の高温高湿耐久試を行い、５００時間保持した後の接続抵抗を測定したところ６０Ωと高い値を示した。また、絶縁抵抗を測定したところ１×１０９以上と十分に高い値を示した。
【００２５】
上記本発明例１、２および比較例１からも分かるように本発明におけるＮｉ合金粒は非晶質Ｎｉ粉末と比較して絶縁抵抗が同等であるものの接続抵抗が低いことから粉末同士の接触によるショートについては同程度であるもの基板および電極との導通性が良好となるから異方性導電膜用粉末として高い性能を有す。
【００２６】
【発明の効果】
本発明によれば異方性導電膜の接続抵抗を低下させ、絶縁抵抗を増加させることが可能となり、異方性導電膜の導電性を飛躍的に改善することができ、異方性導電膜の実用化にとって欠くことのできない技術となる。
【図面の簡単な説明】
【図１】異方性導電膜実装の一例を示す模式図である。
【図２】実質的に非晶質のＮｉＰ合金粒および結晶質のＮｉＰ合金粒のエックス線回折図である。
【図３】実質的に非晶質のＮｉＰ合金粒および結晶質のＮｉＰ合金粒の断面電子顕微鏡写真である。
【図４】実質的に非晶質のＮｉＰ合金粒および結晶質のＮｉＰ合金粒の表面電子顕微鏡写真である。
【符号の説明】
１．ＴＣＰ(Ｔａｐｅ Ｃａｒｒｉｅｒ Ｐａｃｋａｇｅ)、２．樹脂基板、３．電極、４.異方性導電膜用Ｎｉ合金粒[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a Ni alloy grain for an anisotropic conductive film used for an anisotropic conductive film and a method for producing the same.
[0002]
[Prior art]
Anisotropic conductive films are mainly used for electrical connections between display devices such as liquid crystal displays and organic EL displays and semiconductors and substrates, and electrical connections between substrates in electronic products such as personal computers and portable communication devices.
Conventionally, a sphere obtained by performing metal plating on a resin sphere has been used for the conductive particles used in this anisotropic conductive film. Furthermore, recently, in order to reduce the electrical resistance at the time of connection, proposals have been made to use Ni, Cu, Au, Ag and respective alloy powders as conductive particles. Among them, it has been considered preferable to use Ni and its alloy powder.
[0003]
For the conductive particles described above, when using a resin-plated sphere that has been subjected to metal plating, the resin sphere is not only expensive, but the resin sphere is low in hardness and insufficient in hardness to crush the matrix resin. Since the sphere itself is an insulator, there is a problem that there are few conductive parts and conduction is not good.
In order to solve these drawbacks, it has been proposed, for example, in Japanese Patent Laid-Open No. 8-273440 to use Ni, Cu, Au, Ag and respective alloy powders as conductive particles.
[0004]
The conductive particles Au shown in the above-mentioned JP-A-8-273440 are expensive, Ag has the disadvantage of causing migration, and Cu easily oxidizes so that the conductivity is not good. Is easy to oxidize, and since it is hard and difficult to deform, the contact becomes unstable, and the alloy powder of Cu and Ag manufactured by the gas atomization method is the best because it has excellent surface oxidation resistance and suppresses migration It is said that.
However, the alloy powder obtained by the gas atomization method has a relatively large particle size. For example, when trying to obtain an alloy powder of 10 μm or less, the yield is extremely low, which is not economical, but also due to the disadvantages of Cu and Ag. There is a risk of surface oxidation and migration.
[0005]
[Problems to be solved by the invention]
By the way, in order to ensure conduction with an anisotropic conductive film, a method of reducing the hardness of the conductive particles and widening the contact area with the electrode by deformation of the conductive particles, and increasing the hardness of the conductive particles, There are two methods of reliably destroying the oxide film formed on the electrode surface, and the one proposed in the above-mentioned Japanese Patent Laid-Open No. 8-273440 is based on the former idea.
Therefore, the present inventors have intensively studied a method for increasing the hardness of the conductive particles, and the conductive particles used were made of Ni, which has a low risk of migration. As described in Japanese Patent No. 8-273440, it is easily oxidized and is not hard enough to widen the contact area. Moreover, the hardness required to reliably break through the oxide film on the electrode surface is insufficient, and conduction is It was confirmed that it became unstable.
[0006]
Therefore, in order to increase the hardness of Ni, the present inventors have made alloy particles with various alloy elements and at the same time efficiently and uniformly conductive particles having a size of 10 μm or less, which are difficult to obtain by the atomizing method. As a result of studying the method of obtaining a high hardness, the alloy element necessary for increasing the hardness is effective as a metalloid element, and there is no Ni alloy grain having a small and uniform particle size of 10 μm or less, which is difficult to obtain by the atomization method. The electrolytic reduction method can be used, and the Ni alloy particles obtained by this method can be made to have high hardness when the Ni alloy particles are substantially amorphized, and the particle size of the powder itself can be reduced. However, it is necessary to further increase the hardness required for reliably breaking through the oxide film of the electrode, and the substantially amorphous alloy has a high electric resistance, Used as powder for anisotropic conductive film The problem that is difficult occurred.
An object of the present invention is to provide Ni alloy grains for an anisotropic conductive film that have good conductivity when in contact with an electrode in the anisotropic conductive film, and a method for producing the same.
[0007]
[Means for Solving the Problems]
As a result of studying the above problems, the present inventor conducted heat treatment after producing fine substantially amorphous Ni alloy grains by an electroless reduction method as a powder for an anisotropic conductive film, and thereby in the structure. The present inventors have found that the intermetallic compound phase of Ni is precipitated to achieve high hardness, and at the same time, the electrical resistance can be improved.
[0008]
That is, the present invention includes a P or B is N i and metalloids, is composed of the balance unavoidable impurities, a Ni alloy grains of crystalline, the intermetallic compound phase of Ni is precipitated in the tissue Ni alloy grains for anisotropic conductive film characterized by the following.
Further, the Ni alloy particles for anisotropic conductive film of the present invention preferably have a spherical shape with a d90 value of the particle size (particle size of the powder showing 90 vol% of the total in the cumulative distribution curve) of 10 μm or less, and more preferably spherical. Is a Ni alloy grain for anisotropic conductive film in which the surface of the Ni alloy grain for anisotropic conductive film is coated with Au.
[0009]
According to the present invention, in the above-described method for producing Ni alloy particles for an anisotropic conductive film, the Ni alloy particles for the anisotropic conductive film are produced by an electroless reduction method using a phosphoric acid aqueous solution or a boric acid aqueous solution. an anisotropic conductive film for Ni alloy particle manufacturing method thereafter heat-treated to precipitate at least intermetallic compound crystallized and Ni amorphous Ni alloy particles.
Preferably, the amorphous Ni alloy particles produced by electroless reduction method, is said heat treatment was carried out making the anisotropic conductive film for Ni alloy grains of the manufacturing method of after disintegration treatment, more preferably, wherein the anisotropic conductive film for Ni alloy particles after the heat treatment is an anisotropic conductive film for Ni alloy grains of the manufacturing method of coating the Au.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
As described above, an important feature of the present invention is a Ni alloy grain that is substantially composed of Ni and a semimetal as conductive particles for an anisotropic conductive film, and is crystallized between Ni metals in the structure. It exists in the Ni alloy grain for anisotropic conductive films with which the compound phase precipitated.
The present invention is described in detail below.
First, the Ni alloy grain for anisotropic conductive film of the present invention is substantially composed of Ni and a semimetal and has a crystallized metal structure.
The Ni alloy grains for the anisotropic conductive film of the present invention are obtained by crystallizing Ni alloy grains that are substantially amorphous. The kondo effect due to the moment-to-moment conversion interaction increases the electrical resistivity and deteriorates the electrical conductivity. However, by crystallizing this, the above problem is solved, the electrical resistivity is decreased, and the electrical conductivity is improved.
In the present invention, “substantially amorphous” means a state in which the peak of Ni nuclei is detected broadly as shown in FIG.
[0011]
The metalloid referred to in the present invention refers to elements such as C, B, P, Si, As, Te, Ge, and Sb, and these metalloids have an effect of making amorphous and increasing the hardness. Of these elements, the semimetals suitable for the present invention are C, B, and P that can form an intermetallic compound with Ni.
Among them, P not only has the effect of easily spheroidizing the alloy powder, but also enables the precipitation of fine intermetallic compounds composed of Ni 3 P by crystallization by heat treatment to obtain very hard particles. It becomes.
B also has the same effect as P. In the case of B, an Ni 3 B intermetallic compound phase can be precipitated.
In the present invention, it is stipulated that it is substantially composed of Ni and a semi-metal. However, the term "substantially" as used in the present invention refers to a material that is inevitably contained in production in addition to Ni and a semi-metal. Needless to say.
[0012]
In addition, the Ni alloy particles for anisotropic conductive film of the present invention are preferably spherical with a d90 value of 10 μm or less in particle diameter, and by setting the d90 value of particle diameter to 10 μm or less, The proportion of Ni alloy grains for film that are in contact with each other is reduced, the reliability of insulation between adjacent electrodes is improved by narrow pitch connection, the possibility of short-circuiting is reduced, and the insulation between the electrodes is further increased. In addition, it is possible to reduce the thickness of the anisotropic conductive film, and it is possible to sufficiently cope with the fine pitch mounting.
At this time, if the d90 value of the particle diameter of the Ni alloy grains for the anisotropic conductive film is 5 μm or less, it is more preferable because the thickness of the anisotropic conductive film can be further reduced and a fine pitch can be obtained. On the other hand, if the particle size becomes too small, the Ni alloy particles for anisotropic conductive film come into contact with each other and are short-circuited, making it inappropriate as metal particles for anisotropic conductive film. May be 2 μm.
The d90 value is the particle size of the powder showing 90 vol% in the cumulative distribution curve.
[0013]
Further, if the Ni alloy particles of the present invention are spherical, the surface area is increased and the conduction reliability is improved. Therefore, the spherical Ni alloy particles for anisotropic conductive film have the above-mentioned d90 value of the particle size. By satisfying that it is 10 μm or less, it becomes possible to make contact with a large number of powders, and it is possible to reliably obtain good conduction.
In addition, the spherical shape referred to in the present invention is naturally a spherical shape, for example, an elliptical shape as shown in FIG. 4 or a fine spherical particle having a size of 1 μm or less, or some protrusions on the sphere. Even if there is a dent, it is defined as spherical.
[0014]
As described above, the Ni alloy grains for the anisotropic conductive film of the present invention to be described can be manufactured by the following method.
First, in the present invention, substantially amorphous Ni alloy particles that become Ni alloy particles for an anisotropic conductive film are obtained by an electroless reduction method. By making these substantially amorphous Ni alloy grains, the hardness can be increased once.
These substantially amorphous Ni alloy grains are easy to produce powder by the electroless reduction method because Ni as the base phase has a low standard electrode potential, and more easily with semimetals such as Ni and P. Can be obtained in a substantially amorphous state, and since there is no anisotropy, it is possible to obtain spheroidized Ni alloy grains. Is used.
As a specific production method, amorphous Ni-P alloy particles can be obtained by a wet electroless method in which a phosphoric acid aqueous solution is mixed with a sodium hydroxide aqueous solution and a nickel salt is mixed therewith. It is also possible to produce Ni-B alloy particles using a boric acid aqueous solution instead of the aqueous solution.
At this time, it is also possible to adjust the size of the Ni alloy powder obtained by adjusting the amount of the phosphoric acid aqueous solution.
[0015]
The above-mentioned Ni alloy grains may be used as Ni alloy grains for anisotropic conductive films by directly heat-treating those produced by a wet electroless method. In the state of being agglomerated, when conducting, the insulation resistance due to the contact between the particles becomes high, so it is desirable that the Ni alloy grains are pulverized to be made into single particles, and pulverized Thus, it is possible to make the particle diameter of the obtained Ni alloy particles uniform.
The monoparticulation process can be performed by a jet mill or the like, an air classifier, or the like, or by using both of them.
[0016]
Next, in the present invention, the above-described substantially amorphous Ni alloy grains are produced and then crystallized by heat treatment, have a fine structure, and further higher than the substantially amorphous state. Hardened Ni alloy grains for an anisotropic conductive film can be obtained, and it is possible to achieve both the hardness that reliably destroys the oxide film on the electrode surface and excellent electrical resistance.
The heating temperature and time at this time may satisfy the temperature and time at which crystallization and the intermetallic compound of Ni can precipitate, but preferably between 350 ° C. and 450 ° C. for several tens of minutes to several hours. Heat treatment is preferably performed. By this heat treatment, for example, Ni alloy particles for an anisotropic conductive film having a fine particle size of 10 μm or less in which Ni 3 P or Ni 3 B is precipitated can be obtained.
[0017]
Further, in the present invention, it is possible to use the Ni alloy grains for anisotropic conductive film as it is as it is, but Au is applied to the surface of the obtained Ni alloy grains for anisotropic conductive film. By performing the coating treatment, it is possible to further reduce the contact resistance when conducting.
If it is 1 micrometer or less as a layer of a coating process, contact resistance can fully be made low, and what is necessary is just to form a plating layer by a plating process specifically ,.
[0018]
【Example】
The present invention will be described in detail below with reference to examples of the present invention and comparative examples. The present invention is not limited to the following examples as long as the range is not exceeded.
[0019]
Example 1
After sufficiently mixing both sodium hydroxide aqueous solution 0.6 (mol / l) 10 (l) and sodium hypophosphate aqueous solution 1.8 (mol / l) 10 (l), the temperature was raised to 80 ° C. When heated and held and nickel chloride 0.6 (mol / l) and 10 (l) were added, the reaction occurred and fine particles were generated.
The powder was taken out and the structure was confirmed by X-ray diffraction. As a result, it was confirmed that the powder was substantially amorphous as shown in FIG.
Thereafter, the mixture was crushed by a jet mill and the particle size was measured by a laser diffraction method. The d90 value was 4.2 μm, and the spherical NiP alloy particles shown in FIG. 4 were obtained. Thereafter, heat treatment was performed at 400 ° C., and Ni alloy grains for an anisotropic conductive film in which a Ni phase and a Ni 3 P phase were finely precipitated as shown in FIG.
When the cross section of the alloy grain shown in FIGS. 2 (a) and 2 (b) was observed with an electron microscope, an amorphous layer having a Ni nucleus at the center was observed in FIG. 3 (a). In FIG. 3B, finely precipitated Ni 3 P was observed.
[0020]
Next, a composition having a thickness of 20 μm was prepared by adding 25 parts by weight of a bisphenol-based thermosetting resin and 2 parts by weight of an imidazole-based curing agent to 1 part by weight of the Ni alloy particles for the anisotropic conductive film. In the resulting composition (5), Ni alloy grains (4) for anisotropic conductive film are dispersed as shown in FIG. 1 (a). This composition was sandwiched between an electrode (3) provided on a TCP (Tape Carrier Package) (1) and an electrode (3) provided on a resin substrate (2) under the conditions of 170 ° C. and 3 MPa. Connected in seconds. This state is shown in FIG.
Next, a high temperature and high humidity durability test was conducted in which the prototype was held at a temperature of 60 ° C. and a humidity of 90% to investigate the good connection of the prototype. As a result, the connection resistance was 18Ω after a holding time of 500 hours. And a sufficiently low value. Further, when the insulation resistance was measured, it showed a sufficiently high value of 1 × 10 9 or more.
[0021]
(Example 2)
A mixture of sodium hydroxide aqueous solution 0.6 (mol / l) 10 (l) and sodium hypophosphate aqueous solution 2.4 (mol / l) 10 (l) was thoroughly mixed, and the temperature was raised to 60 ° C. When heated and held and nickel chloride 0.6 (mol / l) and 10 (l) were added, the reaction occurred and fine particles were generated.
The Ni alloy grains were picked out and the structure was confirmed by X-ray diffraction. As a result, it was confirmed that the structure was substantially amorphous. Then, the crushing process was performed with the jet mill, and when the particle size was measured by the same method as Example 1, d90 value was 3.1 micrometers. Thereafter, heat treatment was performed at 400 ° C. to prepare Ni alloy grains for anisotropic conductive film in which Ni phase and Ni 3 P phase were finely precipitated.
The powder was further acid-treated with 5% hydrochloric acid, and then electroless Au plating was performed for 30 minutes. After washing with water and checking the plating layer, it was confirmed to be 0.5 μm.
[0022]
A composition having a thickness of 20 μm was prepared by adding 25 parts by weight of a bisphenol-based thermosetting resin and 2 parts by weight of an imidazole-based curing agent to 1 part by weight of the Ni alloy particles for the anisotropic conductive film. In the resulting composition (5), Ni alloy grains (4) for anisotropic conductive film are dispersed as shown in FIG. 1 (a). This composition was sandwiched between the electrode (3) provided on the TCP (1) and the electrode (3) provided on the resin substrate (2) and was connected for 20 seconds under conditions of 170 ° C. and 3 MPa. . This state is shown in FIG.
Next, a high temperature and high humidity durability test at a temperature of 60 ° C. and a humidity of 90% was performed, and the connection resistance after holding for 500 hours was measured to show a sufficiently low value of 8Ω. Further, when the insulation resistance was measured, it showed a sufficiently high value of 1 × 10 9 or more.
[0023]
(Comparative example)
After thoroughly mixing both sodium hydroxide aqueous solution 0.6 (mol / l) 10 (l) and sodium hypophosphate aqueous solution 2.4 (mol / l) 10 (l), the temperature was adjusted to 70 ° C. When heated and held and nickel chloride 0.6 (mol / l) and 10 (l) were added, the reaction occurred and fine particles were generated. When this powder was poured out and the structure was confirmed by X-ray diffraction, it was confirmed to be substantially amorphous. Thereafter, crushing was performed with a jet mill to produce substantially amorphous Ni alloy grains. When the particle diameter was measured by the same method as in Example 1, the d90 value was 2.9 μm.
[0024]
A composition having a thickness of 20 μm consisting essentially of amorphous Ni alloy grains as Ni alloy grains for an anisotropic conductive film, with 1 part by weight, and 25 parts by weight of a bisphenol-based thermosetting resin and 2 parts by weight of an imidazole-based curing agent. Was made. As shown in FIGS. 1 (a) and 1 (b), the obtained composition was sandwiched between the TCP and the resin substrate and connected for 20 seconds under conditions of 170 ° C. and 3 MPa.
Next, a high temperature and high humidity durability test at a temperature of 60 ° C. and a humidity of 90% was performed, and the connection resistance after holding for 500 hours was measured. Further, when the insulation resistance was measured, it showed a sufficiently high value of 1 × 10 9 or more.
[0025]
As can be seen from Examples 1 and 2 of the present invention and Comparative Example 1 above, the Ni alloy grains in the present invention have the same insulation resistance as the amorphous Ni powder, but the connection resistance is low, so the contact between the powders. Although short-circuiting is about the same level, it has high performance as a powder for anisotropic conductive film because of good conductivity with the substrate and electrode.
[0026]
【The invention's effect】
According to the present invention, it is possible to reduce the connection resistance of the anisotropic conductive film and increase the insulation resistance, and to dramatically improve the conductivity of the anisotropic conductive film. It will be an indispensable technology for the practical application of.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an example of mounting an anisotropic conductive film.
FIG. 2 is an X-ray diffraction diagram of substantially amorphous NiP alloy grains and crystalline NiP alloy grains.
FIG. 3 is a cross-sectional electron micrograph of substantially amorphous NiP alloy grains and crystalline NiP alloy grains.
FIG. 4 is a surface electron micrograph of substantially amorphous NiP alloy grains and crystalline NiP alloy grains.
[Explanation of symbols]
1. 1. TCP (Tape Carrier Package) 2. resin substrate; Electrode, 4. Ni alloy grain for anisotropic conductive film
Claims (6)
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| US6909100B2 (en) * | 2002-07-25 | 2005-06-21 | Ii-Vi Incorporated | Radiation detector assembly |
| JP4451760B2 (en) * | 2004-11-09 | 2010-04-14 | 財団法人秋田県資源技術開発機構 | Method for producing spherical NiP fine particles and method for producing conductive particles for anisotropic conductive film |
| JP5327582B2 (en) * | 2007-10-18 | 2013-10-30 | 日立金属株式会社 | Reduction precipitation type spherical NiP fine particles and method for producing the same |
| JP5463052B2 (en) * | 2009-02-17 | 2014-04-09 | 富士フイルム株式会社 | Metal parts |
| JP5695510B2 (en) * | 2011-06-22 | 2015-04-08 | 株式会社日本触媒 | Method for producing conductive fine particles |
| JP6443732B2 (en) | 2014-10-24 | 2018-12-26 | 日立金属株式会社 | Conductive particles, conductive powder, conductive polymer composition and anisotropic conductive sheet |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04170491A (en) * | 1990-11-02 | 1992-06-18 | Oki Electric Ind Co Ltd | Paste for forming thick-film conductor |
| JPH11253886A (en) * | 1998-03-09 | 1999-09-21 | Sekisui Finechem Co Ltd | Fine sphere pneumatic sorting method, conductive fine particle, anisotropic conductive adhesive and consecutively connected structure |
| JP2000087120A (en) * | 1996-11-08 | 2000-03-28 | Akita Pref Gov Shigen Gijutsu Kaihatsu Kiko | SPHERICAL AMORPHOUS Co-P ALLOY POWDER AND ITS PRODUCTION |
| JP2000313906A (en) * | 1999-04-28 | 2000-11-14 | Mitsui Mining & Smelting Co Ltd | Nickel fine powder and its production |
| JP2001279306A (en) * | 2000-03-30 | 2001-10-10 | Akita Pref Gov Shigen Gijutsu Kaihatsu Kiko | METHOD FOR MANUFACTURING SPHERICAL Ni-P AMORPHOUS METAL POWDER |
-
2001
- 2001-04-25 JP JP2001126876A patent/JP4524727B2/en not_active Expired - Lifetime
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04170491A (en) * | 1990-11-02 | 1992-06-18 | Oki Electric Ind Co Ltd | Paste for forming thick-film conductor |
| JP2000087120A (en) * | 1996-11-08 | 2000-03-28 | Akita Pref Gov Shigen Gijutsu Kaihatsu Kiko | SPHERICAL AMORPHOUS Co-P ALLOY POWDER AND ITS PRODUCTION |
| JPH11253886A (en) * | 1998-03-09 | 1999-09-21 | Sekisui Finechem Co Ltd | Fine sphere pneumatic sorting method, conductive fine particle, anisotropic conductive adhesive and consecutively connected structure |
| JP2000313906A (en) * | 1999-04-28 | 2000-11-14 | Mitsui Mining & Smelting Co Ltd | Nickel fine powder and its production |
| JP2001279306A (en) * | 2000-03-30 | 2001-10-10 | Akita Pref Gov Shigen Gijutsu Kaihatsu Kiko | METHOD FOR MANUFACTURING SPHERICAL Ni-P AMORPHOUS METAL POWDER |
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