JP3599149B2 - Conductive paste, electric circuit using conductive paste, and method of manufacturing electric circuit - Google Patents
Conductive paste, electric circuit using conductive paste, and method of manufacturing electric circuit Download PDFInfo
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- JP3599149B2 JP3599149B2 JP21950596A JP21950596A JP3599149B2 JP 3599149 B2 JP3599149 B2 JP 3599149B2 JP 21950596 A JP21950596 A JP 21950596A JP 21950596 A JP21950596 A JP 21950596A JP 3599149 B2 JP3599149 B2 JP 3599149B2
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/09—Use of materials for the conductive, e.g. metallic pattern
- H05K1/092—Dispersed materials, e.g. conductive pastes or inks
- H05K1/095—Dispersed materials, e.g. conductive pastes or inks for polymer thick films, i.e. having a permanent organic polymeric binder
Description
【０００１】
【発明の属する技術分野】
本発明は、導電ペースト、導電ペーストを用いた電気回路及び電気回路の製造法に関する。
【０００２】
【従来の技術】
従来、プリント配線板、電子部品等の電気回路（配線導体）を形成する方法として、電子材料、１９９４年１０月号の４２〜４６頁に記載されているように、導電性に優れた銀粉を含有する導電ペーストを塗布又は印刷する方法が一般的に知られている。
【０００３】
銀粉を用いた導電ペーストは導電性が良好なことから印刷配線板、電子部品等の電気回路や電極として使用されているが、これらの導電性（比抵抗）は通常５０〜１００μΩ・ｃｍであり、優れているものでも３０〜４０μΩ・ｃｍであり、十分なものではなかった。
【０００４】
このため導通抵抗の良好な導体を得るには銀粉の配合量を増加させればよいが、２０μΩ・ｃｍ以下の比抵抗を安定して得ることは困難であった。また銀粉の配合量を単純に増加させると他の特性、例えば接着性とのバランスが悪くなるなどの欠点が生じる。
【０００５】
【発明が解決しようとする課題】
請求項１記載の発明は、比抵抗が低く、高導電性の電気回路形成用の導電ペーストを提供する。
請求項２及び３記載の発明は、請求項１記載の発明のうち特に導電性に優れる電気回路形成用の導電ペーストを提供する。
請求項４記載の発明は、比抵抗が低く、高導電性の電気回路を提供する。
請求項５記載の発明は、請求項４記載の発明に加えてシート抵抗に優れ、また基板との接着性に優れた電気回路を提供する。
請求項６記載の発明は、請求項４又は５記載の発明のうち特に比抵抗が低く、導電性に優れた電気回路を提供する。
【０００６】
請求項７記載の発明は、比抵抗が低く、高導電性の電気回路の製造法を提供する。
請求項８記載の発明は、請求項７記載の発明に加えて回路パターンを低弾性又は耐熱性の低い基板上に転写することが可能な電気回路の製造法を提供する。
請求項９記載の発明は、請求項７又は８記載の発明のうち特に比抵抗が低く、導電性に優れ、さらに請求項７又は８記載の発明に加えてシート抵抗に優れた電気回路の製造法を提供する。
【０００７】
【課題を解決するための手段】
本発明は、扁平状導電粉、不定形状導電粉、バインダ及び溶剤を含む導電ペーストにおいて、主成分がＢステージ状態の熱硬化性樹脂であるバインダを導電ペーストの固形分に対して２０〜５０体積％含有してなる導電ペーストに関する。
また、本発明は、アスペクト比が５以上の導電粉、アスペクト比が３以下の導電粉、バインダ及び溶剤を含む導電ペーストにおいて、主成分がＢステージ状態の熱硬化性樹脂であるバインダを導電ペーストの固形分に対して２０〜５０体積％含有してなる導電ペーストに関する。
また、本発明は、導電粉の材質が銀又は銀合金である導電ペーストに関する。
【０００８】
また、本発明は、上記の導電ペーストを用いて基板の表面に形成された電気回路に関する。
また、本発明は、電気回路が接着剤層を介して基板と接合された電気回路に関する。
また、本発明は、基板の表面に形成された電気回路の比抵抗が１５μΩ・ｃｍ以下である電気回路に関する。
【０００９】
また、本発明は、基板の表面に上記の導電ペーストで回路パターンを形成した後、加熱、加圧、硬化することを特徴とする電気回路の製造法に関する。
また、本発明は、電気回路が接着性を有する基板上に転写法で形成されることを特徴とする電気回路の製造法に関する。
さらに、本発明は、基板の表面に形成された電気回路の比抵抗が１５μΩ・ｃｍ以下であることを特徴とする電気回路の製造法に関する。
【００１０】
本発明において、扁平状導電粉と不定形状導電粉の組合せ又はアスペクト比が５以上の導電粉と３以下の不定形状電導粉の組合せの場合、導電粉同士の接触確率が改善でき、電気回路の導電性が高くなり、特にシート状の基板に印刷回路をプレス加工する場合の導電性を高めることができる。
【００１１】
本発明における、導電粉のアスペクト比とは、導電粉の粒子の長径と短径の比率（長径／短径）をいう。本発明においては、粘度の低い硬化性樹脂中に導電粉の粒子をよく混合し、静置して粒子を沈降させるとともにそのまま樹脂を硬化させ、得られた硬化物を垂直方向に切断し、その切断面に現れる粒子の形状を電子顕微鏡で拡大して観察し、少なくとも１００の粒子について一つ一つの粒子の長径／短径を求め、それらの平均値をもってアスペクト比とする。
ここで、短径とは、前記切断面に現れる粒子について、その粒子の外側に接する二つの平行線の組合せを粒子を挾むように選択し、これらの組合せのうち最短間隔になる二つの平行線の距離である。一方、長径とは、前記短径を決する平行線に直角方向の二つの平行線であって、粒子の外側に接する二つの平行線の組合せのうち、最長間隔になる二つの平行線の距離である。これらの四つの線で形成される長方形は、粒子がちょうどその中に納まる大きさとなる。
なお、本発明において行った具体的方法については後述する。
【００１２】
扁平状導電粉とは、形状としてほぼ平坦で微細な小片からなる導電粉で、例えば、りん片状導電粉がある。不定形状導電粉とは、扁平状以外の形状の導電粉で、球状、立方体状、四面体状、塊状、略球状等と呼ばれる粉体、こんぺい糖のように表面に突起のある形状の粉体、これらの混合物等種々の導電粉のことである。種々の形状の導電粉を含むものとしては、例えば還元銀粉がある。
扁平状導電粉及び不定形状導電粉のそれぞれに対応してアスペクト比が５以上の導電粉及びアスペクト比が３以下の導電粉を使用することができる。
【００１３】
アスペクト比が５以上の導電粉としては多くの場合、扁平状導電粉が該当し、この他に樹枝状（デンドライト状とも呼ばれる）などと呼ばれる形状のものがあり、このものも併用して用いることができる。アスペクト比が５以上の導電粉としては、高導電性のペーストが得られるという点で、アスペクト比が７以上が好ましく、アスペクト比が８以上がより好ましく、アスペクト比が１０以上がさらに好ましい。よって、形状とアスペクト比の両面から述べると、高導電性、導電ペーストの粘度等の面からアスペクト比が７以上の扁平状導電粉がより好ましく、アスペクト比が８以上の扁平状導電粉がさらに好ましく、アスペクト比が１０以上の扁平状導電粉が最も好ましい。
【００１４】
扁平状導電粉又はアスペクト比が５以上の導電粉の粒子の平均粒子径としては、印刷性を低下させないという観点から、２５μｍ以下のものが好ましく、２０μｍ以下のものがより好ましく、１０μｍ以下のものがさらに好ましい。なお、ここでいう平均粒子径は、レーザー散乱型粒度分布測定装置により測定することができる。本発明においては、前記装置としてマスターサイザー（マルバン社製）を用いて測定した。
【００１５】
アスペクト比が３以下の導電粉としては、前記した不定形状導電粉の多くが該当する。アスペクト比が３以下の導電粉としては、高導電性のペーストが得られるという点で、アスペクト比が２．５以下が好ましく、アスペクト比が２以下がさらに好ましい。
【００１６】
不定形状導電粉又はアスペクト比が３以下の導電粉の平均粒子径は、印刷性に優れる点で、３〜２０μｍの範囲が好ましく、３〜１０μｍの範囲がさらに好ましい。なお、ここでいう平均粒子径は、前記と同様に、レーザー散乱型粒度分布測定装置により測定することができる。本発明においては、前記装置としてマスターサイザー（マルバン社製）を用いて測定した。
【００１７】
各導電粉の材質は、銀又は銀合金が導電性並びに耐酸化性の点で好ましい。
上記の銀合金としては、パラジウム（例えば銀合金中に１〜５重量％程度）、白金（例えば銀合金中に１重量％程度）等との合金を用いることが好ましい。
また上記の銀粉を作製する方法の一つに液中還元法があり、この方法によって作製される銀粉は平均粒径が数μｍの微粉末であることから工業的な生産方法として広く利用されている。この液中還元法とは、銀を酸で溶解した後、これをアルカリで中和し、次いでこれにホルマリン、デンプン等の還元剤を添加して液中で還元して微粉末とする方法であり、これによって得られる粉末を還元銀粉といい、その形状は、塊状に近いが一定の形状ではなく不規則な形状をしている。この還元銀粉は本発明において不定形状導電粉又はアスペクト比が３以下の導電粉として使用できる。
【００１８】
扁平状導電粉と不定形状導電粉又はアスペクト比が５以上の導電粉とアスペクト比が３以下の導電粉との配合割合は、扁平状導電粉又はアスペクト比が５以上の導電粉が９５〜４０重量％に対し、不定形状導電粉又はアスペクト比が３以下の導電粉が５〜６０重量％の範囲であることが導電性を高める点で好ましく、扁平状導電粉又はアスペクト比が５以上の導電粉が８５〜６０重量％に対し、不定形状導電粉又はアスペクト比が３以下の導電粉が１５〜４０重量％の範囲であることがさらに好ましい。
また、これらの導電粉の含有量は導電ペーストの固形分に対して、８０〜５０体積％の範囲が好ましく、６５〜５０体積％の範囲であることがさらに好ましい。
【００１９】
バインダとしては、主成分がＢステージ状態の熱硬化性樹脂、詳しくは、液状のエポキシ樹脂、フェノール樹脂、不飽和ポリエステル樹脂等の有機質の接着剤成分が用いられ、該バインダの含有量は導電ペーストの固形分に対して２０〜５０体積％、好ましくは３０〜５０体積％、さらに好ましくは４０〜５０体積％の範囲とされ、２０体積％未満であると導電体層の接着強度が低下し易くなり、５０体積％を超えると加熱加圧条件によって導電性にばらつきが生じ易くなる。
本発明において体積％とは各々の重量を密度で除して算出した体積ベースの割合を示す。
【００２０】
また溶剤としては、テルピネオール、エチルカルビトール、カルビトールアセテート、ブチルセロソルブ等が用いられる。導電ペーストは上記の材料以外に２エチル４メチルイミダゾールなどの有機質の接着剤成分の硬化剤及び必要に応じてカップリング剤、ベンゾチアゾール、ベンゾイミダゾール等の腐食抑制剤などを添加して均一に混合して得られる。溶剤の含有量は、導電ペーストに対して１０〜３５重量％の範囲であることが好ましく、１５〜２５重量％の範囲であることがさらに好ましい。また硬化剤の含有量は、作業性の点でバインダに対して１〜１０重量％の範囲であることが好ましく、１〜５重量％の範囲であることがさらに好ましい。
【００２１】
カップリング剤及び腐食抑制剤は必要に応じて添加されるが、もし添加する場合その添加量は、カップリング剤はバインダに対して０．００５〜０．０５重量％の範囲であることが好ましく、０．０１〜０．０２重量％の範囲であることがさらに好ましい。腐食抑制剤はバインダに対して０．００５〜０．０５重量％の範囲であることが好ましく、０．００５〜０．０１重量％の範囲であることがさらに好ましい。
上記の材料は、導電ペーストの全組成物全体が１００体積％となるように配合される。
【００２２】
本発明において、Ｂステージ状態の熱硬化性樹脂とは、熱硬化性樹脂の単量体（モノマ）が一部反応して粘度が上昇しているが、流動性を失うまで硬化反応が進行しておらず半硬化状態のことを指し、このＢステージ状態の熱硬化性樹脂を用いることにより、導電ペースを塗布した後に、短時間に溶剤を留去させるのみで加熱加圧する際のバインダの成形性を一定の範囲にコントロールできるので好ましい。
【００２３】
Ｂステージ状態の熱硬化性樹脂は、熱硬化性樹脂に２エチル４メチルイミダゾールなどの硬化剤を添加して、低温（４０〜８０℃）で加熱し、それを冷却することにより得ることができる。上記の熱硬化性樹脂としては、前記と同様に液状のエポキシ樹脂、フェノール樹脂、不飽和ポリエステル樹脂等の有機質の接着剤成分を用いることができる。
【００２４】
電気回路の形成方法については特に制限はなく、公知の方法、例えば導電ペーストをスクリーン印刷、コンピュータでコントロールした描画機で形成することができる。
基板としては、ポリエチレンテレフタレートフィルム、ポリイミドフィルム、ポリアミドイミドフィルム、紙フェノール積層板、エポキシ樹脂ガラス布基材積層板、ポリイミド樹脂ガラス布基材積層板等が用いられる。なおこれらの基板には電気回路との接着性を向上させるために予め接着剤層を形成しておくことが好ましい。
【００２５】
本発明においては、基板の表面に導電ペーストで回路パターンを形成した後、加熱、加圧、硬化して電気回路を形成してもよく、またはく離が可能なシート状又は板状の基材に回路パターンを形成し、それを加熱、加圧、硬化した後、表面が接着性を有する基板上に転写する方法で電気回路を形成してもよい。特に後者の場合は、基板の耐熱性、耐圧性等の制限もなく、任意の基板上に所望の電気回路を形成することができる。
【００２６】
本発明において、電気回路の比抵抗は、好ましくは１５μΩ・ｃｍ以下、より好ましくは１２μΩ・ｃｍ以下とされ、１５μΩ・ｃｍを超えると導電性が低下する傾向があるため、電気回路の電圧降下が大きくなり、微細な電気回路にはしにくくなる。なお電気回路の比抵抗が１０μΩ・ｃｍ以下であれば、微細で、かつコイル状の平面アンテナなどのような線の長さが長い電気回路に用いることができるので特に好ましい。電気回路の比抵抗を１５μΩ・ｃｍ以下にするには、基材の表面に上記の導電ペーストで回路パターンを形成した後、例えばプレスで加圧して回路パターンを緻密化することにより達成できる。プレスの方法は、定盤を用いて圧力をかける方法、ロールでプレスする方法等が適用され、導電ペーストで形成した導電層中の粉末同士の接触効率を高めることができればよい。なおプレスするときに導電層中のバインダは軟化していることが好ましい。バインダの硬化はプレス後に硬化させてもよく、プレス中に硬化させてもよい。
【００２７】
【実施例】
以下本発明の実施例を説明する。
実施例１
ビスフェノールＡ型エポキシ樹脂（油化シェルエポキシ（株）製、商品名エピコート１００４）３０重量部及びレゾール型フェノール樹脂（日立化成工業（株）製、商品名ＶＰ−１１Ｎ、平均分子量４５０）７０重量部を予め混合したものに、２エチル４メチルイミダゾール１重量部を加えて混合し、樹脂組成物を得た。次いでこの樹脂組成物１０１重量部にエチルカルビトール３５０重量部及びブチルセロソルブ３５０重量部を加えて均一に混合して樹脂溶液を得た。
【００２８】
次にアスペクト比が７で、長径の平均粒径が１０．５μｍのリン片状銀粉（徳力化学研究所製、商品名ＴＣＧ−１）２１００重量部（４８体積％）及びアスペクト比が２．２で、長径の平均粒径が５μｍのフジ化学研究所製の還元銀粉１４００重量部（３２体積％）を配合し、次いでこのものを上記で得た樹脂溶液８０１重量部に添加し、撹拌らいかい機で均一に混合、分散して導電ペーストを得た。なおバインダは導電ペーストの固形分に対して２０体積％であった。
【００２９】
この後、上記で得た導電ペーストを用いて、表面に平均２．４ｇ／ｍ２の割合に接着剤（上記で得た樹脂組成物にエチルカルビトール３０重量部及びブチルセロソルブ３０重量部を加えて均一に混合した溶液）を塗布したポリエチレンテレフタレートフィルム（厚さ１２５μｍ）上に図１に示す回路パターン１を印刷（形成）し、次いで大気中で８０℃で６０分間乾燥した後、１００℃に加熱したプレスを用いて圧力５ＭＰａで２分間の条件で加熱加圧し、その後１４５℃で３０分間硬化して電気回路を形成してその特性を評価した。その結果、電気回路の比抵抗は７．５μΩ・ｃｍであり、シート抵抗は４．０ｍΩ／□で接着状態も良好であった。なお図１において２はポリエチレンテレフタレートフィルムである。
【００３０】
次に本実施例におけるアスペクト比の具体的測定法を以下に示す。低粘度のエポキシ樹脂（ビューラー社製）の主剤（Ｎｏ．２０−８１３０）８ｇと硬化剤（Ｎｏ．２０−８１３２）２ｇを混合し、ここへ導電粉２ｇを混合して良く分散させ、そのまま３０℃で真空脱泡した後、６〜８時間３０℃で静置して粒子を沈降させ硬化させた。その後、得られた硬化物を垂直方向に切断し、切断面を電子顕微鏡で２０００倍に拡大して切断面に現われた１００個の粒子について長径／短径を求め、それらの平均値をもって、アスペクト比とした。
【００３１】
実施例２
実施例１で得た樹脂組成物１０１重量部にエチルカルビトール１５０重量部及びブチルセロソルブ１５０重量部を加えて均一に混合して樹脂溶液を得た。
次に実施例１で用いたりん片状銀粉１７５０重量部（５９．５体積％）及び還元銀粉３１０重量部（１０．５体積％）を配合し、次いでこのものを上記で得た樹脂溶液４０１重量部に添加し、実施例１と同様の方法で均一に混合、分散して導電ペーストを得た。なおバインダは導電ペーストの固形分に対して３０体積％であった。
【００３２】
以下ポリエチレンテレフタレートフィルム上への接着剤の塗布量を１．３ｇ／ｍ２とした以外は、実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電気回路の比抵抗は８．２μΩ・ｃｍであり、シート抵抗は４．３ｍΩ／□で接着状態も良好であった。
【００３３】
実施例３
実施例１で得た樹脂組成物１０１重量部にエチルカルビトール６５重量部及びブチルセロソルブ６５重量部を加えて均一に混合して樹脂溶液を得た。
次に実施例１で用いたりん片状銀粉８１０重量部（４１．３体積％）及び還元銀粉２７０重量部（１３．７体積％）を配合し、次いでこのものを上記で得た樹脂溶液２３１重量部に添加し、実施例１と同様の方法で均一に混合、分散して導電ペーストを得た。なおバインダは導電ペーストの固形分に対して４５体積％であった。
以下実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電化回路の比抵抗は９．５μΩ・ｃｍであり、シート抵抗は８．９ｍΩ／□で接着状態も良好であった。
【００３４】
実施例４
実施例１で用いたりん片平状銀粉１３２０重量部（５２体積％）及び還元銀粉３３０重量部（１３体積％）を配合し、次いでこのものを実施例３で得た樹脂溶液２３１重量部に添加し、実施例１と同様の方法で均一に混合、分散して導電ペーストを得た。なおバインダは導電ペーストの固形分に対して３５体積％であった。
以下実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電気回路の比抵抗は８．５μΩ・ｃｍであり、シート抵抗は７．７ｍΩ／□で接着状態も良好であった。
【００３５】
実施例５
実施例１で得た導電ペーストを用いてポリエチレンテレフタレートフィルム上に実施例１と同様の回路パターンを印刷（形成）し、以下実施例１と同様の工程を経て電気回路を形成した。
一方、別のポリエチレンテレフタレートフィルムの表面に実施例１で用いた接着剤を平均２．１ｇ／ｍ２の割合に塗布し、乾燥させた後、このフィルム上に電気回路を形成したフィルムの電気回路を形成した面を下側にして重ね、次いでヒートロールを用いて温度１００℃±５℃、９．８ＭＰａの条件で接着剤を塗布した側のフィルム上に電気回路を転写した。なお電気回路の特性は実施例１と同じであった。
【００３６】
比較例１
実施例１の回路パターンの加熱加圧工程を省略し、導電ペーストとして実施例３で得た導電ペーストを用いた以外は実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電気回路の比抵抗は３９μΩ・ｃｍと高く、またシート抵抗も３５ｍΩ／□と高かった。なお接着状態は良好であった。
【００３７】
実施例６
ビスフェノールＡ型エポキシ樹脂（油化シェルエポキシ（株）製、商品名エピコート１００４）３０重量部及びレゾール型フェノール樹脂（日立化成工業（株）製、商品名ＶＰ−１１Ｎ、平均分子量４５０）７０重量部を予め混合したものに、２エチル４メチルイミダゾール１重量部を加え、８０℃で３時間混合してＢステージ状態に反応させた樹脂組成物を得た。次いでこの樹脂組成物１０１重量部にエチルカルビトール３５０重量部及びブチルセロソルブ３５０重量部を加えて均一に混合して樹脂溶液を得た。
【００３８】
次にアスペクト比が７で、長径の平均粒径が１０．５μｍのりん片状銀粉（徳力化学研究所製、商品名ＴＣＧ−１）２１００重量部（４８体積％）及びアスペクト比が２．２で、長径の平均粒径が５μｍのフジ化学研究所製の還元銀粉１４００重量部（３２体積％）を配合し、次いでこのものを上記で得た樹脂溶液８０１重量部に添加し、撹拌らいかい機で均一に混合、分散して導電ペーストを得た。なおバインダは導電ペーストの固形分に対して２０体積％であった。
【００３９】
以下回路パターンの乾燥時間を１００℃で３分間、加熱加圧条件における加熱温度を１１０℃とした以外は、実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電気回路の比抵抗は７．２μΩ・ｃｍであり、シート抵抗は３．９ｍΩ／□で接着状態も良好であった。
【００４０】
実施例７
実施例６で得たＢステージ状態に反応させた樹脂組成物１０１重量部にエチルカルビトール１５０重量部及びブチルセロソルブ１５０重量部を加えて均一に混合して樹脂溶液を得た。
次に実施例６で用いたりん片状銀粉１７５０重量部（５９．５体積％）及び還元銀粉３１０重量部（１０．５体積％）を配合し、次いでこのものを上記で得た樹脂溶液４０１重量部に添加し、実施例６と同様の方法で均一に混合、分散して導電ペーストを得た。なおバインダは導電ペーストの固形分に対して３０体積％であった。
【００４１】
以下ポリエチレンテレフタレートフィルム上への接着剤の塗布量を１．３ｇ／ｍ２とした以外は、実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電気回路の比抵抗は８．０μΩ・ｃｍであり、シート抵抗は４．２ｍΩ／□で接着状態も良好であった。
【００４２】
実施例８
実施例６で得たＢステージ状態に反応させた樹脂組成物１０１重量部にエチルカルビトール６５重量部及びブチルセロソルブ６５重量部を加えて均一に混合して樹脂溶液を得た。
次に実施例６で用いたりん片状銀粉８１０重量部（４１．３体積％）及び還元銀粉２７０重量部（１３．７体積％）を配合し、次いでこのものを上記で得た樹脂溶液２３１重量部に添加し、実施例６と同様の方法で均一に混合、分散して導電ペーストを得た。なおバインダは導電ペーストの固形分に対して４５体積％であった。
以下実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電気回路の比抵抗は９．０μΩ・ｃｍであり、シート抵抗は８．４ｍΩ／□で接着状態も良好であった。
【００４３】
実施例９
実施例６で用いたりん片状銀粉１３２０重量部（５２体積％）及び還元銀粉３３０重量部（１３体積％）を配合し、次いでこのものを実施例８で得た樹脂溶液２３１重量部に添加し、実施例６と同様の方法で均一に混合、分散して導電ペーストを得た。なおバインダは導電ペーストの固形分に対して３５体積％であった。
以下実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電気回路の比抵抗は８．０μΩ・ｃｍであり、シート抵抗は７．４ｍΩ／□で接着状態も良好であった。
【００４４】
実施例１０
実施例６で得た導電ペーストを用いてポリエチレンテレフタレートフィルム上に実施例１と同様の回路パターンを印刷（形成）し、以下実施例１と同様の工程を経て電気回路を形成した。
一方、別のポリエチレンテレフタレートフィルムの表面に実施例１で用いた接着剤を平均２．１ｇ／ｍ２の割合に塗布し、乾燥させた後、このフィルム上に電気回路を形成したフィルムの電気回路を形成した面を下側にして重ね、次いでヒートロールを用いて温度１００℃±５℃、９．８ＭＰａの条件で接着剤を塗布した側のフィルム上に電気回路を転写した。なお電気回路の特性は実施例６と同じであった。
【００４５】
比較例２
実施例１の回路パターンの加熱加圧工程を省略し、導電ペーストとして実施例８で得た導電ペーストを用いた以外は実施例１と同様の工程を経て電気回路を形成し、その特性を評価した。その結果、電気回路の比抵抗は３９μΩ・ｃｍと高く、またシート抵抗も３５ｍΩ／□と高かった。なお接着状態は良好であった。
【００４６】
【発明の効果】
請求項１記載の導電ペーストは、比抵抗が低く、高導電性の電気回路形成用に最適である。
請求項２及び３記載の導電ペーストは、請求項１記載の導電ペーストの効果を奏し、特に導電性に優れる。
請求項４記載の電気回路は、比抵抗が低く、高導電性である。
請求項５記載の電気回路は、請求項４記載の電気回路の効果に加えてシート抵抗に優れ、また基板との接着性に優れる。
請求項６記載の電気回路は、請求項４又５記載の電気回路の効果を奏し、特に導電性に優れる。
請求項７記載の電気回路の製造法は、比抵抗が低く、高導電性の電気回路が製造できる。
請求項８記載の電気回路の製造法は、請求項７記載の電気回路の製造法の効果に加えて回路パターンを低弾性又は耐熱性の低い基板上に転写することが可能な電気回路が製造できる。
請求項９記載の電気回路の製造法は、請求項７又は８記載の電気回路の製造法の効果を奏し、特に導電性に優れ、さらに請求項７又は８記載の電気回路の製造法の効果に加えてシート抵抗に優れる電気回路が製造できる。
【図面の簡単な説明】
【図１】ポリエチレンテレフタレートフィルムに回路パターンを印刷した状態を示す平面図である。
【符号の説明】
１ 回路パターン
２ ポリエチレンテレフタレートフィルム[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a conductive paste, an electric circuit using the conductive paste, and a method for manufacturing an electric circuit.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a method for forming an electric circuit (wiring conductor) such as a printed wiring board or an electronic component, as described in Electronic Materials, October 1994, pp. 42 to 46, silver powder excellent in conductivity is used. A method of applying or printing a contained conductive paste is generally known.
[0003]
A conductive paste using silver powder is used as an electric circuit or an electrode of a printed wiring board, an electronic component, or the like because of its good conductivity, but the conductivity (resistivity) thereof is usually 50 to 100 μΩ · cm. It was 30 to 40 μΩ · cm, which was not sufficient even if it was excellent.
[0004]
Therefore, in order to obtain a conductor having good conduction resistance, it is sufficient to increase the compounding amount of silver powder, but it has been difficult to stably obtain a specific resistance of 20 μΩ · cm or less. Further, if the amount of silver powder is simply increased, disadvantages such as poor balance with other properties, for example, adhesion, occur.
[0005]
[Problems to be solved by the invention]
The first aspect of the present invention provides a conductive paste for forming an electric circuit having low specific resistance and high conductivity.
The inventions according to claims 2 and 3 provide a conductive paste for forming an electric circuit which is particularly excellent in conductivity among the inventions according to claim 1.
The invention according to claim 4 provides an electric circuit having low specific resistance and high conductivity.
According to a fifth aspect of the present invention, there is provided an electric circuit having excellent sheet resistance and excellent adhesion to a substrate in addition to the fourth aspect of the invention.
According to a sixth aspect of the present invention, there is provided an electric circuit having a low specific resistance and an excellent conductivity, among the inventions according to the fourth or fifth aspect.
[0006]
The invention according to claim 7 provides a method of manufacturing an electric circuit having low specific resistance and high conductivity.
According to an eighth aspect of the present invention, in addition to the seventh aspect of the present invention, there is provided a method of manufacturing an electric circuit capable of transferring a circuit pattern onto a substrate having low elasticity or low heat resistance.
Invention of claim 9, low especially specific resistance of the present invention according to claim 7, high conductivity, the production of electric circuit having excellent sheet resistance in addition to the further invention of claim 7 or 8, wherein Provide the law.
[0007]
[Means for Solving the Problems]
The present invention provides a conductive paste containing flat conductive powder, irregular-shaped conductive powder, a binder and a solvent, wherein a binder whose main component is a thermosetting resin in a B-stage state is 20 to 50 volumes with respect to the solid content of the conductive paste. % Of the conductive paste.
Further, the present invention provides a conductive paste containing a conductive powder having an aspect ratio of 5 or more, a conductive powder having an aspect ratio of 3 or less, a binder and a solvent, wherein a binder whose main component is a B-staged thermosetting resin is used as a conductive paste. A conductive paste containing 20 to 50% by volume based on the solid content of the conductive paste.
The present invention also relates to a conductive paste in which the material of the conductive powder is silver or a silver alloy.
[0008]
The present invention also relates to an electric circuit formed on a surface of a substrate using the conductive paste.
Further, the present invention relates to an electric circuit in which the electric circuit is bonded to a substrate via an adhesive layer.
Further, the present invention relates to an electric circuit in which the electric circuit formed on the surface of the substrate has a specific resistance of 15 μΩ · cm or less.
[0009]
Further, the present invention relates to a method for manufacturing an electric circuit, which comprises heating, pressing and curing after forming a circuit pattern on the surface of a substrate with the above conductive paste.
Further, the present invention relates to a method for manufacturing an electric circuit, wherein the electric circuit is formed on a substrate having adhesiveness by a transfer method.
Furthermore, the present invention relates to a method for manufacturing an electric circuit, wherein the electric circuit formed on the surface of the substrate has a specific resistance of 15 μΩ · cm or less.
[0010]
In the present invention, in the case of a combination of flat conductive powder and irregular-shaped conductive powder or a combination of an electrically conductive powder having an aspect ratio of 5 or more and an irregular-shaped conductive powder of 3 or less, the contact probability between the conductive powders can be improved, and The conductivity is increased, and particularly when the printed circuit is pressed on a sheet-like substrate, the conductivity can be increased.
[0011]
In the present invention, the aspect ratio of the conductive powder refers to the ratio of the major axis to the minor axis (major axis / minor axis) of the conductive powder particles. In the present invention, the particles of the conductive powder are mixed well in a low-viscosity curable resin, and the resin is cured while allowing the particles to settle by standing, and the resulting cured product is cut in the vertical direction. The shape of the particles appearing on the cut surface is observed under magnification with an electron microscope, and the major axis / minor axis of each particle is obtained for at least 100 particles, and the average value thereof is defined as the aspect ratio.
Here, the minor axis is defined as a combination of two parallel lines contacting the outside of the particle with respect to the particle appearing on the cut surface so as to sandwich the particle. Distance. On the other hand, the major axis is two parallel lines perpendicular to the parallel line that determines the minor axis, and is the distance between the two parallel lines that are the longest among the combinations of the two parallel lines that contact the outside of the particle. is there. The rectangle formed by these four lines is sized to fit the particle exactly inside it.
The specific method used in the present invention will be described later.
[0012]
The flat conductive powder is a conductive powder composed of fine particles that are almost flat in shape and, for example, flaky conductive powder. Irregular shaped conductive powders are conductive powders with shapes other than flat, such as powders that are spherical, cubic, tetrahedral, massive, roughly spherical, etc., or powders that have protrusions on the surface, such as sugary sugar. It refers to various conductive powders such as a body and a mixture thereof. Examples of the conductive powder containing various shapes of conductive powder include reduced silver powder.
A conductive powder having an aspect ratio of 5 or more and a conductive powder having an aspect ratio of 3 or less can be used corresponding to the flat conductive powder and the irregular-shaped conductive powder, respectively.
[0013]
In many cases, the conductive powder having an aspect ratio of 5 or more corresponds to a flat conductive powder, and in addition, there is a shape called a dendritic shape (also called a dendrite shape), which should be used in combination. Can be. As the conductive powder having an aspect ratio of 5 or more, an aspect ratio of 7 or more is preferable, an aspect ratio of 8 or more is more preferable, and an aspect ratio of 10 or more is more preferable in that a highly conductive paste is obtained. Therefore, from the viewpoint of both the shape and the aspect ratio, the flat conductive powder having an aspect ratio of 7 or more is more preferable from the viewpoint of high conductivity, the viscosity of the conductive paste, and the like, and the flat conductive powder having an aspect ratio of 8 or more is more preferable. Preferably, a flat conductive powder having an aspect ratio of 10 or more is most preferable.
[0014]
The average particle diameter of the particles of the flat conductive powder or the conductive powder having an aspect ratio of 5 or more is preferably 25 μm or less, more preferably 20 μm or less, and more preferably 10 μm or less, from the viewpoint of not reducing printability. Is more preferred. Here, the average particle size can be measured by a laser scattering type particle size distribution measuring device. In the present invention, the measurement was performed using a master sizer (manufactured by Malvern) as the device.
[0015]
As the conductive powder having an aspect ratio of 3 or less, many of the above-mentioned irregularly shaped conductive powders correspond. As the conductive powder having an aspect ratio of 3 or less, an aspect ratio of 2.5 or less is preferable, and an aspect ratio of 2 or less is more preferable, in that a highly conductive paste can be obtained.
[0016]
The average particle diameter of the irregularly shaped conductive powder or the conductive powder having an aspect ratio of 3 or less is preferably in the range of 3 to 20 μm, more preferably 3 to 10 μm, from the viewpoint of excellent printability. In addition, the average particle diameter here can be measured by a laser scattering type particle size distribution measuring device in the same manner as described above. In the present invention, the measurement was performed using a master sizer (manufactured by Malvern) as the device.
[0017]
As the material of each conductive powder, silver or a silver alloy is preferable in terms of conductivity and oxidation resistance.
As the above silver alloy, it is preferable to use an alloy with palladium (for example, about 1 to 5% by weight in a silver alloy), platinum (for example, about 1% by weight in a silver alloy), or the like.
In addition, one of the methods for producing the silver powder is a submerged reduction method, and the silver powder produced by this method is a fine powder having an average particle size of several μm, and is widely used as an industrial production method. I have. This in-liquid reduction method is a method in which silver is dissolved in an acid, then neutralized with an alkali, and then a reducing agent such as formalin or starch is added thereto and reduced in the liquid to form a fine powder. The resulting powder is called reduced silver powder, and its shape is close to a lump but is not a fixed shape but an irregular shape. This reduced silver powder can be used in the present invention as a conductive powder having an irregular shape or a conductive powder having an aspect ratio of 3 or less.
[0018]
The mixing ratio of the flat conductive powder and the irregular shaped conductive powder or the conductive powder having an aspect ratio of 5 or more and the conductive powder having an aspect ratio of 3 or less is such that the flat conductive powder or the conductive powder having an aspect ratio of 5 or more is 95 to 40. It is preferable that the amorphous conductive powder or the conductive powder having an aspect ratio of 3 or less is in the range of 5 to 60% by weight based on the weight% in terms of enhancing the conductivity, and the flat conductive powder or the conductive powder having an aspect ratio of 5 or more is preferable. It is further preferable that the irregularly shaped conductive powder or the conductive powder having an aspect ratio of 3 or less is in the range of 15 to 40% by weight based on 85 to 60% by weight of the powder.
The content of these conductive powders is preferably in the range of 80 to 50% by volume, more preferably in the range of 65 to 50% by volume, based on the solid content of the conductive paste.
[0019]
As the binder, a thermosetting resin whose main component is a B-stage state, specifically , an organic adhesive component such as a liquid epoxy resin, a phenol resin, and an unsaturated polyester resin is used, and the content of the binder is a conductive paste. 20 to 50% by volume, preferably 30 to 50% by volume, and more preferably 40 to 50% by volume, based on the solid content, and if it is less than 20% by volume, the adhesive strength of the conductor layer tends to decrease. becomes, it tends to occur unevenness 50 vol% conductive by heat and pressure conditions as is exceeded.
In the present invention, the term “% by volume” indicates a volume-based ratio calculated by dividing each weight by the density.
[0020]
As the solvent, terpineol, ethyl carbitol, carbitol acetate, butyl cellosolve and the like are used. In addition to the above materials, the conductive paste is added with a hardener of an organic adhesive component such as 2-ethyl-4-methylimidazole and, if necessary, a coupling agent and a corrosion inhibitor such as benzothiazole and benzimidazole, and uniformly mixed. Is obtained. The content of the solvent is preferably in the range of 10 to 35% by weight based on the conductive paste, and more preferably in the range of 15 to 25% by weight. Further, the content of the curing agent is preferably in the range of 1 to 10% by weight, more preferably 1 to 5% by weight, based on the workability in terms of the binder.
[0021]
The coupling agent and the corrosion inhibitor are added as needed, and if added, the amount of the coupling agent is preferably in the range of 0.005 to 0.05% by weight based on the binder. , 0.01 to 0.02% by weight. The corrosion inhibitor is preferably in the range of 0.005 to 0.05% by weight, more preferably 0.005 to 0.01% by weight, based on the binder.
The above materials are blended so that the entire composition of the conductive paste becomes 100% by volume.
[0022]
In the present invention, with the thermosetting resin in the B-stage state, the monomer (monomer) of the thermosetting resin partially reacts to increase the viscosity, but the curing reaction proceeds until the fluidity is lost. It refers to a semi-cured state without using it, and by using this thermosetting resin in the B-stage state, after applying a conductive pace, forming a binder when heating and pressurizing only by distilling off the solvent in a short time. It is preferable because the properties can be controlled within a certain range.
[0023]
The B-stage thermosetting resin can be obtained by adding a curing agent such as 2-ethyl-4-methylimidazole to the thermosetting resin, heating at a low temperature (40 to 80 ° C.), and cooling it. . As the thermosetting resin, an organic adhesive component such as a liquid epoxy resin, a phenol resin, and an unsaturated polyester resin can be used as described above.
[0024]
The method for forming the electric circuit is not particularly limited, and the electric circuit can be formed by a known method, for example, screen printing of a conductive paste or a drawing machine controlled by a computer.
As the substrate, a polyethylene terephthalate film, a polyimide film, a polyamideimide film, a paper-phenol laminate, an epoxy resin glass cloth substrate laminate, a polyimide resin glass cloth substrate laminate, or the like is used. Note that it is preferable that an adhesive layer is formed on these substrates in advance in order to improve adhesiveness to an electric circuit.
[0025]
In the present invention, after forming a circuit pattern with a conductive paste on the surface of the substrate, an electric circuit may be formed by heating, pressing, and curing, or on a sheet-like or plate-like substrate that can be separated. An electric circuit may be formed by a method of forming a circuit pattern, heating, pressurizing and curing the circuit pattern, and then transferring the circuit pattern onto a substrate having an adhesive surface. In particular, in the latter case, a desired electric circuit can be formed on an arbitrary substrate without limitation on heat resistance, pressure resistance, and the like of the substrate.
[0026]
In the present invention, the specific resistance of the electric circuit is preferably 15 μΩ · cm or less, more preferably 12 μΩ · cm or less, and if it exceeds 15 μΩ · cm, the conductivity tends to decrease. It becomes difficult to make a fine electric circuit. Note that it is particularly preferable that the specific resistance of the electric circuit be 10 μΩ · cm or less, since the electric circuit can be used for an electric circuit having a long wire such as a fine and coiled planar antenna. The specific resistance of the electric circuit can be reduced to 15 μΩ · cm or less by forming a circuit pattern on the surface of the base material using the above-mentioned conductive paste, and then pressurizing the circuit pattern with a press, for example, to densify the circuit pattern. As a pressing method, a method of applying pressure using a surface plate, a method of pressing with a roll, or the like is applied, as long as the contact efficiency between powders in a conductive layer formed of a conductive paste can be increased. Note arbitrariness preferred that the binder of the conductive layer is softened when the press. The binder may be cured after pressing, or may be cured during pressing.
[0027]
【Example】
Hereinafter, embodiments of the present invention will be described.
Example 1
30 parts by weight of bisphenol A type epoxy resin (trade name: Epicoat 1004, manufactured by Yuka Shell Epoxy Co., Ltd.) and 70 parts by weight of resol type phenol resin (trade name: VP-11N, average molecular weight 450, manufactured by Hitachi Chemical Co., Ltd.) Was mixed in advance with 1 part by weight of 2-ethyl-4-methylimidazole to obtain a resin composition. Next, 350 parts by weight of ethyl carbitol and 350 parts by weight of butyl cellosolve were added to 101 parts by weight of the resin composition and uniformly mixed to obtain a resin solution.
[0028]
Next, 2100 parts by weight (48% by volume) of flaky silver powder (trade name: TCG-1 manufactured by Tokurika Kagaku Kenkyusho) having an aspect ratio of 7 and a long average particle diameter of 10.5 μm, and an aspect ratio of 2.2. Then, 1400 parts by weight (32% by volume) of reduced silver powder manufactured by Fuji Chemical Laboratories having a long diameter of 5 μm and an average particle diameter of 5 μm were blended, and then added to 801 parts by weight of the resin solution obtained above and stirred. The conductive paste was obtained by uniformly mixing and dispersing with a machine. The binder was 20% by volume based on the solid content of the conductive paste.
[0029]
Thereafter, using the conductive paste obtained above, an adhesive was added to the surface at an average ratio of 2.4 g / m 2 (30 parts by weight of ethyl carbitol and 30 parts by weight of butyl cellosolve were added to the resin composition obtained above. The circuit pattern 1 shown in FIG. 1 is printed (formed) on a polyethylene terephthalate film (thickness 125 μm) coated with a homogeneously mixed solution), dried in air at 80 ° C. for 60 minutes, and then heated to 100 ° C. Heating and pressurizing was performed at a pressure of 5 MPa for 2 minutes using a press, and then cured at 145 ° C. for 30 minutes to form an electric circuit, and its characteristics were evaluated. As a result, the specific resistance of the electric circuit was 7.5 μΩ · cm, the sheet resistance was 4.0 mΩ / □, and the bonding state was good. In FIG. 1, reference numeral 2 denotes a polyethylene terephthalate film.
[0030]
Next, a specific method of measuring the aspect ratio in this embodiment will be described below. 8 g of a base material (No. 20-8130) of a low-viscosity epoxy resin (manufactured by Buehler Co.) and 2 g of a curing agent (No. 20-8132) are mixed, and 2 g of conductive powder is mixed and dispersed well, and the mixture is left as it is. After degassing in vacuo at ℃, the particles were allowed to stand at 30 ℃ for 6 to 8 hours to settle and harden the particles. Thereafter, the obtained cured product was cut in the vertical direction, and the cut surface was magnified 2000 times with an electron microscope to determine the major axis / minor axis for 100 particles appearing on the cut surface. Ratio.
[0031]
Example 2
To 101 parts by weight of the resin composition obtained in Example 1, 150 parts by weight of ethyl carbitol and 150 parts by weight of butyl cellosolve were added and uniformly mixed to obtain a resin solution.
Next, 1750 parts by weight (59.5% by volume) of flaky silver powder used in Example 1 and 310 parts by weight (10.5% by volume) of reduced silver powder were blended, and then this was mixed with the resin solution 401 obtained above. It was added to parts by weight and uniformly mixed and dispersed in the same manner as in Example 1 to obtain a conductive paste. The binder was 30% by volume based on the solid content of the conductive paste.
[0032]
Hereinafter, an electric circuit was formed through the same steps as in Example 1 except that the amount of the adhesive applied onto the polyethylene terephthalate film was 1.3 g / m 2, and its characteristics were evaluated. As a result, the specific resistance of the electric circuit was 8.2 μΩ · cm, the sheet resistance was 4.3 mΩ / □, and the bonding state was good.
[0033]
Example 3
To 101 parts by weight of the resin composition obtained in Example 1, 65 parts by weight of ethyl carbitol and 65 parts by weight of butyl cellosolve were added and uniformly mixed to obtain a resin solution.
Next, 810 parts by weight (41.3% by volume) of flaky silver powder used in Example 1 and 270 parts by weight (13.7% by volume) of reduced silver powder were blended, and then this was mixed with the resin solution 231 obtained above. It was added to parts by weight and uniformly mixed and dispersed in the same manner as in Example 1 to obtain a conductive paste. The binder was 45% by volume based on the solid content of the conductive paste.
Thereafter, an electric circuit was formed through the same steps as in Example 1, and its characteristics were evaluated. As a result, the specific resistance of the electric circuit was 9.5 μΩ · cm, the sheet resistance was 8.9 mΩ / □, and the adhesion state was good.
[0034]
Example 4
1320 parts by weight (52% by volume) of the flaky silver powder used in Example 1 and 330 parts by weight (13% by volume) of reduced silver powder were blended, and then added to 231 parts by weight of the resin solution obtained in Example 3. Then, the mixture was uniformly mixed and dispersed in the same manner as in Example 1 to obtain a conductive paste. The binder was 35% by volume based on the solid content of the conductive paste.
Thereafter, an electric circuit was formed through the same steps as in Example 1, and its characteristics were evaluated. As a result, the specific resistance of the electric circuit was 8.5 μΩ · cm, the sheet resistance was 7.7 mΩ / □, and the bonding state was good.
[0035]
Example 5
The same circuit pattern as in Example 1 was printed (formed) on a polyethylene terephthalate film using the conductive paste obtained in Example 1, and an electric circuit was formed through the same steps as in Example 1 below.
On the other hand, the adhesive used in Example 1 was applied to the surface of another polyethylene terephthalate film at an average ratio of 2.1 g / m 2 and dried, and then the electric circuit of the film having an electric circuit formed on the film was formed. Then, the electric circuit was transferred onto the film on the side on which the adhesive was applied at a temperature of 100 ° C. ± 5 ° C. and 9.8 MPa using a heat roll. The characteristics of the electric circuit were the same as those of the first embodiment.
[0036]
Comparative Example 1
An electric circuit was formed through the same steps as in Example 1 except that the heating and pressurizing step of the circuit pattern of Example 1 was omitted, and the conductive paste obtained in Example 3 was used as the conductive paste, and its characteristics were evaluated. did. As a result, the specific resistance of the electric circuit was as high as 39 μΩ · cm, and the sheet resistance was as high as 35 mΩ / □. The bonding state was good.
[0037]
Example 6
30 parts by weight of bisphenol A type epoxy resin (trade name: Epicoat 1004, manufactured by Yuka Shell Epoxy Co., Ltd.) and 70 parts by weight of resol type phenol resin (trade name: VP-11N, average molecular weight 450, manufactured by Hitachi Chemical Co., Ltd.) Was added in advance, and 1 part by weight of 2-ethyl-4-methylimidazole was added thereto, followed by mixing at 80 ° C. for 3 hours to obtain a resin composition reacted in the B-stage state. Next, 350 parts by weight of ethyl carbitol and 350 parts by weight of butyl cellosolve were added to 101 parts by weight of the resin composition and uniformly mixed to obtain a resin solution.
[0038]
Next, 2100 parts by weight (48% by volume) of flaky silver powder (trade name: TCG-1 manufactured by Tokurika Kagaku Kenkyusho) having an aspect ratio of 7 and a long average particle diameter of 10.5 μm, and an aspect ratio of 2.2. Then, 1400 parts by weight (32% by volume) of reduced silver powder manufactured by Fuji Chemical Laboratories having a long diameter of 5 μm and an average particle diameter of 5 μm were blended, and then added to 801 parts by weight of the resin solution obtained above and stirred. The conductive paste was obtained by uniformly mixing and dispersing with a machine. The binder was 20% by volume based on the solid content of the conductive paste.
[0039]
Hereinafter, an electric circuit was formed through the same steps as in Example 1 except that the drying time of the circuit pattern was 100 ° C. for 3 minutes and the heating temperature under the heating and pressing conditions was 110 ° C., and its characteristics were evaluated. As a result, the specific resistance of the electric circuit was 7.2 μΩ · cm, the sheet resistance was 3.9 mΩ / □, and the bonding state was good.
[0040]
Example 7
150 parts by weight of ethyl carbitol and 150 parts by weight of butyl cellosolve were added to 101 parts by weight of the resin composition reacted in the B-stage state obtained in Example 6, and uniformly mixed to obtain a resin solution.
Next, 1750 parts by weight (59.5% by volume) of the flaky silver powder used in Example 6 and 310 parts by weight (10.5% by volume) of the reduced silver powder were blended, and then this was mixed with the resin solution 401 obtained above. It was added to parts by weight and uniformly mixed and dispersed in the same manner as in Example 6 to obtain a conductive paste. The binder was 30% by volume based on the solid content of the conductive paste.
[0041]
Hereinafter, an electric circuit was formed through the same steps as in Example 1 except that the amount of the adhesive applied onto the polyethylene terephthalate film was 1.3 g / m 2, and its characteristics were evaluated. As a result, the specific resistance of the electric circuit was 8.0 μΩ · cm, the sheet resistance was 4.2 mΩ / □, and the adhesion state was good.
[0042]
Example 8
To 101 parts by weight of the resin composition reacted in the B-stage state obtained in Example 6, 65 parts by weight of ethyl carbitol and 65 parts by weight of butyl cellosolve were added and uniformly mixed to obtain a resin solution.
Next, 810 parts by weight (41.3% by volume) of the flaky silver powder used in Example 6 and 270 parts by weight (13.7% by volume) of reduced silver powder were blended, and then this was mixed with the resin solution 231 obtained above. It was added to parts by weight and uniformly mixed and dispersed in the same manner as in Example 6 to obtain a conductive paste. The binder was 45% by volume based on the solid content of the conductive paste.
Thereafter, an electric circuit was formed through the same steps as in Example 1, and its characteristics were evaluated. As a result, the specific resistance of the electric circuit was 9.0 μΩ · cm, the sheet resistance was 8.4 mΩ / □, and the bonding state was good.
[0043]
Example 9
1320 parts by weight (52% by volume) of flaky silver powder used in Example 6 and 330 parts by weight (13% by volume) of reduced silver powder were blended, and then added to 231 parts by weight of the resin solution obtained in Example 8. Then, the mixture was uniformly mixed and dispersed in the same manner as in Example 6 to obtain a conductive paste. The binder was 35% by volume based on the solid content of the conductive paste.
Thereafter, an electric circuit was formed through the same steps as in Example 1, and its characteristics were evaluated. As a result, the specific resistance of the electric circuit was 8.0 μΩ · cm, the sheet resistance was 7.4 mΩ / □, and the bonding state was good.
[0044]
Example 10
The same circuit pattern as in Example 1 was printed (formed) on a polyethylene terephthalate film using the conductive paste obtained in Example 6, and an electric circuit was formed through the same steps as in Example 1 below.
On the other hand, the adhesive used in Example 1 was applied on the surface of another polyethylene terephthalate film at an average rate of 2.1 g / m 2 and dried, and then the electric circuit of the film having an electric circuit formed on the film was formed. Then, the electric circuit was transferred onto the film on the side on which the adhesive was applied at a temperature of 100 ° C. ± 5 ° C. and 9.8 MPa using a heat roll. The characteristics of the electric circuit were the same as in Example 6.
[0045]
Comparative Example 2
An electric circuit was formed through the same steps as in Example 1 except that the heating and pressurizing step of the circuit pattern of Example 1 was omitted, and the conductive paste obtained in Example 8 was used as the conductive paste, and its characteristics were evaluated. did. As a result, the specific resistance of the electric circuit was as high as 39 μΩ · cm, and the sheet resistance was as high as 35 mΩ / □. The bonding state was good.
[0046]
【The invention's effect】
The conductive paste according to the first aspect has a low specific resistance and is most suitable for forming an electric circuit having high conductivity.
The conductive paste according to claims 2 and 3 has the effect of the conductive paste according to claim 1, and is particularly excellent in conductivity.
The electric circuit according to claim 4 has low specific resistance and high conductivity.
The electric circuit according to claim 5 is excellent in sheet resistance in addition to the effect of the electric circuit according to claim 4 , and is excellent in adhesion to a substrate.
The electric circuit according to the sixth aspect has the effects of the electric circuit according to the fourth or fifth aspect , and is particularly excellent in conductivity.
According to the method for manufacturing an electric circuit according to claim 7, an electric circuit having low specific resistance and high conductivity can be manufactured.
According to the method for manufacturing an electric circuit according to claim 8 , in addition to the effect of the method for manufacturing an electric circuit according to claim 7, an electric circuit capable of transferring a circuit pattern onto a substrate having low elasticity or low heat resistance is manufactured. it can.
The method for manufacturing an electric circuit according to the ninth aspect has the effects of the method for manufacturing an electric circuit according to the seventh or eighth aspect , and is particularly excellent in conductivity, and the effect of the method for manufacturing an electric circuit according to the seventh or eighth aspect. In addition, an electric circuit having excellent sheet resistance can be manufactured.
[Brief description of the drawings]
FIG. 1 is a plan view showing a state in which a circuit pattern is printed on a polyethylene terephthalate film.
[Explanation of symbols]
1 Circuit pattern 2 Polyethylene terephthalate film
Claims (9)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21950596A JP3599149B2 (en) | 1996-08-21 | 1996-08-21 | Conductive paste, electric circuit using conductive paste, and method of manufacturing electric circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21950596A JP3599149B2 (en) | 1996-08-21 | 1996-08-21 | Conductive paste, electric circuit using conductive paste, and method of manufacturing electric circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1064331A JPH1064331A (en) | 1998-03-06 |
| JP3599149B2 true JP3599149B2 (en) | 2004-12-08 |
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| JP21950596A Expired - Lifetime JP3599149B2 (en) | 1996-08-21 | 1996-08-21 | Conductive paste, electric circuit using conductive paste, and method of manufacturing electric circuit |
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Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000007824A (en) * | 1998-06-22 | 2000-01-11 | Jsr Corp | Electroconductive composition and transfer film for forming electrode |
| GB0106417D0 (en) * | 2001-03-15 | 2001-05-02 | Oxford Biosensors Ltd | Transfer screen-printing |
| WO2003075295A1 (en) * | 2002-03-07 | 2003-09-12 | Tdk Corporation | Laminate type electronic component |
| JP3823870B2 (en) | 2002-04-22 | 2006-09-20 | セイコーエプソン株式会社 | Wiring board manufacturing method and electronic device manufacturing method |
| JP2006073668A (en) * | 2004-08-31 | 2006-03-16 | Sumitomo Electric Ind Ltd | Wiring circuit and its forming method |
| JP2006210202A (en) * | 2005-01-28 | 2006-08-10 | Sekisui Chem Co Ltd | Manufacturing method of plastic sheet with circuit |
| JP4738923B2 (en) * | 2005-07-15 | 2011-08-03 | 東光株式会社 | Manufacturing method of multilayer inductor for high current |
| JP2008166595A (en) * | 2006-12-28 | 2008-07-17 | Tdk Corp | Chip component |
| JP5846524B2 (en) * | 2010-04-13 | 2016-01-20 | 学校法人立命館 | Method for forming conductive pattern and substrate device |
| JP5662104B2 (en) * | 2010-10-26 | 2015-01-28 | 京セラケミカル株式会社 | Conductive resin composition and semiconductor device using the same |
| WO2013035685A1 (en) | 2011-09-05 | 2013-03-14 | ナミックス株式会社 | Conductive resin composition and cured object using same |
| CN104966547B (en) * | 2015-07-14 | 2017-05-24 | 上海无线电设备研究所 | Conductive silver paste for on-paper printing and preparation method thereof |
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1996
- 1996-08-21 JP JP21950596A patent/JP3599149B2/en not_active Expired - Lifetime
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