JP3618441B2 - Conductive metal composite powder and manufacturing method thereof - Google Patents
Conductive metal composite powder and manufacturing method thereof Download PDFInfo
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- JP3618441B2 JP3618441B2 JP02076496A JP2076496A JP3618441B2 JP 3618441 B2 JP3618441 B2 JP 3618441B2 JP 02076496 A JP02076496 A JP 02076496A JP 2076496 A JP2076496 A JP 2076496A JP 3618441 B2 JP3618441 B2 JP 3618441B2
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- noble metal
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- 239000000843 powder Substances 0.000 title claims description 113
- 239000002905 metal composite material Substances 0.000 title claims description 79
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 229910000510 noble metal Inorganic materials 0.000 claims description 135
- 239000010970 precious metal Substances 0.000 claims description 7
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 58
- 229910052709 silver Inorganic materials 0.000 description 56
- 239000004332 silver Substances 0.000 description 56
- 239000010410 layer Substances 0.000 description 53
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 52
- 239000002245 particle Substances 0.000 description 32
- 239000010949 copper Substances 0.000 description 28
- 238000013508 migration Methods 0.000 description 25
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- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 6
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 6
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 6
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
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Images
Description
【０００１】
【発明の属する技術分野】
本発明は、電気回路形成用の導電性ペーストに適した導電性金属複合粉及びその製造法に関する。
【０００２】
【従来の技術】
従来、配線板、電子部品を搭載するための絶縁基材等に配線導体を形成する方法として、金、銀、パラジウム、銅、アルミニウム等の導電性金属粉に、樹脂、ガラスフリット等の結合剤及び溶剤を加えてペースト状にした導電性ペーストを塗布又は印刷して形成する方法が一般的に知られており、スルホール導通用、電極形成用、ジャンパ線用、ＥＭＩシールド用等に応用されている。
各種導電性金属粉のうち、金は極めて高価であるため、高い導電性が要求される分野では銀が、それ以外の分野では銅が導電性金属粉として用いられることが多い。
【０００３】
しかしながら、銀は金やパラジウムについで高価であり、また水分の存在下で直流電圧が印加されると、電極や配線導体にマイグレーションと称する銀の電析が生じ、電極間又は配線間が短絡するという重大な問題点が生じる。
銀のマイグレーションを防止するため、銀とパラジウムとの合金を導電性金属粉とする導電性材料が市販されているが、やはり極めて高価であるという問題点がある。
【０００４】
一方、銅は安価であり、マイグレーションが比較的生じにくいが、導電性ペーストを加熱する際、空気及び結合剤中の酸素により銅粒子表面に酸化膜を形成して導電性を悪化させるという問題点がある。このため、導体の表面に防湿塗料を塗布したり、導電性材料に腐食、酸化防止剤を添加するなどの方策が検討されているが、十分な効果が得られるものではなかった。
【０００５】
銅の耐酸化性と銀の耐マイグレーション性を改善するため、銀めっき銅粉を使用する方法が特開昭５６−８８９２号公報に示されるが、この方法では銀粉に比較して導電性が悪く、銀粉の一部を銅粉に置き換えただけにすぎない。また特開平３−２４７７０２号公報、特開平４−２６８３８１号公報等に提案されているように、銅の表面に銀の粒子をアトマイズ法で作製する方法があるが、この方法では工程が複雑であるためコスト高となり、また得られた粉体は略球形粒子であるため偏平状や樹枝状の粉体に比べて粉体同士の接触面積が小さく、高抵抗になるという問題点がある。
【０００６】
【発明が解決しようとする課題】
請求項１記載の発明は、導電性で、導電性と耐マイグレーション性に優れる導電性金属複合粉を提供するものである。
請求項２記載の発明は、請求項１記載の発明に加えて、特に耐マイグレーション性に優れた導電性金属複合粉を提供するものである。
請求項３記載の発明は、請求項１記載の発明に加えて、特に導電性と耐マイグレーション性に優れた導電性金属複合粉を提供するものである。
請求項４記載の発明は、請求項１記載の発明に加えて、特に導電性に優れた導電性金属複合粉を提供するものである。
請求項５記載の発明は、安価で、かつ高導電性で、耐マイグレーション性に優れる導電性金属複合粉の製造法を提供するものである。
【０００７】
【課題を解決するための手段】
本発明は、偏平状非貴金属粉の全表面積の５０％以上が、該偏平状非貴金属粉に対して２〜３０重量％の貴金属で被覆され、かつ表面貴金属層と非貴金属層との間に貴金属と非貴金属とが混在する層を介在してなる導電性金属複合粉であって、貴金属と非貴金属とが混在する層が、表面貴金属層の厚さの１／２〜１／５０である導電性金属複合粉に関する。
また、本発明は、この導電性金属複合粉において、貴金属と非貴金属とが混在する層が、貴金属が８０〜２０原子数％に対し非貴金属が２０〜８０原子数％である導電性金属複合粉に関する。
また、本発明は、この導電性金属複合粉において、表面貴金属層の厚さが、０．０１〜０．２μｍである導電性金属複合粉に関する。
また、本発明は、この導電性金属複合粉の長径／厚さが、２〜３０である導電性金属複合粉に関する。
また、本発明は、非貴金属粉の表面に、該非貴金属粉に対して２〜３０重量％の貴金属を被覆した後、機械的エネルギーを加えることにより、偏平状の変形及び表面貴金属層と非貴金属層との間に、貴金属と非貴金属とが混在する層の形成を行うことを特徴とする導電性金属複合粉の製造法に関する。
【０００８】
【発明の実施の形態】
本発明における偏平状とは、球状、塊状等の立体形状のものを一方向に押し潰した形状のものであり、例えば一般的にフレーク状と称するものもこれに含まれる。
【０００９】
本発明において用いられる非貴金属粉としては、低価格という観点から、導電性を有する非貴金属で、例えば銅、銅合金、ニッケル等が用いられる。また非貴金属粉の表面に被覆される貴金属は、耐酸化性と高導電性という観点から、金、銀、白金等の貴金属を用いることが好ましい。
【００１０】
非貴金属粉への表面に貴金属を被覆する方法については特に制限はなく、めっき法、蒸着法、機械的エネルギーで被覆するメカノフュージョン法等の方法で行うことが好ましい。偏平状非貴金属粉が貴金属により被覆される面積（以下、単に被覆面積という）は偏平状非貴金属粉の全表面積に対して５０％以上であり、また、この被覆に使用される貴金属の量（以下、単に被覆量という）は、偏平状非貴金属粉に対して２〜３０重量％であることが必要である。被覆面積が５０％未満又は被覆量が２重量％未満であると、導電性ペーストにして基板などに塗布して加熱処理したとき下地の偏平状非貴金属粉が酸化して導電性が悪くなる。また被覆量が３０重量％を超えると耐マイグレーション性が悪くなる。
被覆面積は、次のようにして決定される。すなわち、無作為に導電性金属複合粉の粒子を５個以上取り出し、オージェ分光分析装置で貴金属及び非貴金属を定量分析し、貴金属の占める割合を算出し、その平均値を求め、この平均値を被覆面積とする。
また、非貴金属と貴金属との割合は、例えば導電性金属複合粉を１ｇ取り出し、これを硝酸で溶解し、この溶解液を化学定量分析、原子吸光分析装置等を用いて測定する。
上記の被覆面積は５０％以上とされるが、非貴金属粉の粒子に局部電池が形成され貴金属の溶出が抑制できる点で非貴金属粉の表面の一部が露出することが好ましい。特に貴金属が銀である場合、銅、ニッケル等の非貴金属粉を組み合わせて用いることにより、銀のマイグレーション性が改善され優れた効果を示すので好ましい。また被覆量は７〜２５重量％が好ましく、１５〜２０重量％であればさらに好ましい。
【００１１】
本発明でいう貴金属と非貴金属とが混在する層とは、被覆層を形成するのに使用される貴金属と基材層の非貴金属成分の両者が混合された状態にあり、本発明では貴金属と非貴金属が混在する層の厚さが、表面貴金属層の厚さに対して１／２〜１／５０の場合に優れた導電性と耐マイグレーション性を示す。貴金属と非貴金属が混在する層の厚さが表面貴金属層の厚さの１／２を超えるか又は１／５０未満の場合は導電性が著しく悪化する傾向がある。貴金属と非貴金属が混在する層の厚さは、表面貴金属層の厚さに対して１／２〜１／４０であることがより好ましく、１／２〜１／３０であることがさらに好ましい。
表面貴金属層の厚さ及び貴金属と非貴金属とが混在する層の厚さは、それぞれ無作為に導電性金属複合粉の粒子を５個以上取り出し、イオンスパッタリングで表面を削っていくと同時に元素定量分析するオージェ分光分析装置などを用いて１個の粒子について３点以上測定し、それぞれの厚さについての平均値を求め、この平均値をそれぞれの厚さと決定する。
【００１２】
本発明になる導電性金属複合粉の貴金属と非貴金属とが混在する層は、貴金属８０〜２０原子数％に対し非貴金属２０〜８０原子数％を含むものであることが、優れた導電性と耐マイグレーション性を示す点で好ましい。
また、本発明になる導電性金属複合粉は、ペースト化し、さらにスクリーン印刷して使用するような場合、表面貴金属層の厚さが０．０１〜０．２μｍであることが、導電性と耐マイグレーション性に優れるので好ましい。厚さが０．０１μｍ未満であると導電性が悪くなる傾向があり、厚さが０．２μｍを超えると耐マイグレーション性が悪くなる傾向がある。
【００１３】
本発明になる導電性金属複合粉において、偏平状非貴金属粉の長径／厚さが、２〜３０であることが、優れた導電性と耐酸化性を示す点で好ましく、５〜２０であることがより好ましく、７〜１５であることがさらに好ましい。偏平状非貴金属粉の長径／厚さが２未満であると粉同士の接触がほとんど点接触となるため高抵抗となる傾向があり、３０を超えると貴金属を３０重量％被覆しても全表面積の５０％以上が被覆されたものを作製することが困難となり、導電性ペーストとしたものを基板などに塗布して加熱処理したとき、下地の非貴金属粉が酸化し導電性が悪化する傾向がある。
なお、長径については絶対値で１００μｍ以下が好ましく、５０μｍ以下であることがより好ましく、３０μｍ以下であることがさらに好ましい。導電性金属複合粉の長径／厚さは、走査型電子顕微鏡を用いて導電性金属複合粉のＳＥＭ写真をとり、この中から導電性金属複合粉の粒子を無作為に３０個以上選び、それの長径／厚さを測定し、その平均値を求め、この平均値を導電性金属複合粉の長径／厚さとする。
【００１４】
本発明の導電性金属複合粉の製造法について、基材となる非貴金属粉の平均粒径や形状については特に制限はない。また貴金属の被覆方法については、コストと特性のバランスの点から、レーザー法、沈降法等の一般的な粒度分布測定法で求めた平均粒径が１〜３０μｍ以下の銅粉に銀をめっき又は蒸着する方法が好ましい。
【００１５】
本発明における偏平状に変形した導電性金属複合粉は、非貴金属粉の表面に貴金属を被覆した後、メカニカルアロイング装置、乾式ボールミリング装置、ロール等による圧縮装置又は高速で固い物質に粉体を吹き付ける装置等を用いて機械的エネルギーを加えることにより製造することができる。
貴金属で表面が被覆された非貴金属粉に機械的エネルギーを加えることにより、貴金属中又は表面貴金属層と非貴金属層との間に存在したボイド（空隙）がなくなり、これによって被覆される貴金属層が緻密化され、その導電性が高められる。また、このとき、表面貴金属層と非貴金属層との間に貴金属と非貴金属とが混在する薄い領域が形成され、これにより表面貴金属層と非貴金属層間の接触抵抗を小さくすることができる。
【００１６】
本発明になる導電性金属複合粉を用いて導電性ペーストを作製するために加える結合剤は、エポキシ樹脂、フェノール樹脂、不飽和ポリエステル樹脂、飽和ポリエステル樹脂、ポリアミド樹脂、ポリイミド樹脂、ポリアミドイミド樹脂、アクリル樹脂等の有機結合剤又はガラスフリットなどの無機結合剤が挙げられ、さらに必要に応じて硬化促進剤及び溶剤が添加され、硬化促進剤としては、イミダゾール、アミン類等が挙げられ、また溶剤としては、ブチルセロソルブ、テルピネオール、エチレンカルビトール、カルビトールアセテート等が挙げられる。
導電性ペーストは、導電性金属複合粉に結合剤及び必要に応じて硬化促進剤及び溶剤を加えて、らいかい機、ロール、ニーダ等で均一に混合して得られる。結合剤の含有量は、導電性ペーストに対して５〜３０重量％が好ましく、８〜１６重量％であることがさらに好ましい。硬化促進剤及び溶剤は必要に応じて添加されるが、もし添加する場合その含有量は、硬化促進剤は導電性ペーストに対して０．０１〜１重量％が好ましく、０．０２〜０．０５重量％であることがさらに好ましい。また溶剤は導電性ペーストに対して３〜５０重量％が好ましく、１０〜３０重量％であることがさらに好ましい。
【００１７】
本発明になる導電性金属複合粉を用いた導電性ペーストは、絶縁基材として用いられる各種基板、各種フィルム等に塗布、印刷、ポッティングして配線導体を形成する材料として最適であり、その他スルーホール導通用、電極形成用、ジャンパ線用、ＥＭＩシールド用等の形成に用いることができる。また抵抗素子、チップ抵抗、チップコンデンサ等の電子部品と絶縁基材を接続する導電性接着剤、鉛レスはんだ代替材としても使用できる。
【００１８】
上記に示す各種基板としては、紙フェノール基板、ガラスエポキシ基板、ホウロウ基板、セラミック基板等が挙げられ、また各種フィルムとしては、ポリエチレン、ポリカーボネート、塩化ビニル、ポリスチレン、ポリエチレンテレフタレート、ポリフェニレンスルフィド、ポリエーテルケトン、ポリエーテルイミド、ポリイミド等フレキシブルな樹脂製のフィルムが挙げられる。
なお絶縁基材は、表面やスルホールに、予め、めっき、印刷、蒸着、エッチング等の方法で導体や抵抗の一部を形成したものを用いてもよい。
【００１９】
【実施例】
以下本発明の実施例を説明する。
実施例１
平均粒径が５μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）を酸性クリーナ（日本マクダーミッド（株）製、商品名Ｌ−５Ｂ）で脱指、水洗し、水１リットルあたりＡｇＣＮを２０ｇ及びＮａＣＮを１０ｇ含むめっき浴で球形銅粉に対して銀の量が２０重量％になるように置換めっきを行い、水洗、乾燥して銀めっき銅粉を得た。
【００２０】
次に、この銀めっき銅粉をＭＡ（メカニカルアロイング）装置に投入して以下の条件で変形処理した。本装置はスクリューの回転でボールを運動させる方式であり、ボール及び被処理粉体を投入する容器の有効容積は１．１リットルである。本装置に４ｋｇのジルコニアボール（直径１０ｍｍ）と２００ｇの銀めっき銅粉を投入し、スクリューの回転数９０ｒｐｍ及び容器内圧力２×１０−５ｔｏｒｒの条件で２時間回転して導電性金属複合粉（偏平状銀めっき銅粉）を得た。
【００２１】
次いで走査型電子顕微鏡を用いて上記で得た導電性金属複合粉のＳＥＭ写真をとり、該導電性金属複合粉の粒子を３０個選び、長径／厚さを測定したところ２〜１５の範囲で平均が６であった。なお長径は、２〜３０μｍの範囲で平均が１５μｍであった。
また無作為に導電性金属複合粉の粒子を５個取り出し、走査型オージェ電子分光分析装置で貴金属及び非貴金属を定量分析して銀被覆面積について調べたところ、全表面積に対して４５〜８５％の範囲で平均が７０％であった。
さらに無作為に導電性金属複合粉の粒子を５個取り出し、イオンスパッタリングで表面を削っていくと同時に元素定量分析する走査型オージェ電子分光分析装置で１個の粒子につき３点測定したところ、銀層の厚さは０．０２〜０．１５μｍの範囲で平均が０．０４５μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層の厚さは０．００１〜０．０５μｍの範囲で平均が０．０１μｍであり、表面貴金属層の厚さの１／２０〜１／２の範囲で平均が１／４．５であった。
以下の実施例及び比較例においても上記と同様の方法で測定した。
【００２２】
上記の導電性金属複合粉１００重量部に対し、ノボラツク型フェノール樹脂
（群栄化学工業（株）製、商品名ＰＳ−２６０７）１５重量部及び溶剤としてブチルセロソルブ１５重量部を加えて均一に混合して導電性ペーストを得た。
【００２３】
次いで導電性ペーストを厚さが１．６ｍｍの紙フェノール銅張積層板（日立化成工業（株）製、商品名ＭＣＬ−４３７Ｆ）の銅箔を除去した積層板の上面に２００メッシュのスクリーンを通して幅０．４ｍｍ及び長さ１００ｍｍのテストパターンを印刷し、大気中で１５０℃で３０分の条件で加熱処理して配線導体を得た。得られた配線導体における導電性ペースト硬化物の比抵抗は平均７５μΩＣｍであり、後述する銀ペーストと比べて遜色のない導電性を示した。
【００２４】
一方上記とは別に導電性ペーストをガラス板上に幅２ｍｍの電極を互いに２ｍｍ間隔となるように上記と同様の方法で印刷し、大気中で１５０℃で３０分の条件で加熱処理して硬化させて電極を得た。次いで電極間に幅２ｍｍに切断したろ紙を配置し、イオン交換水０．５ｃｃをろ紙上に滴下して電極間に２０Ｖの直流電圧を印加し、経過時間と電極間漏洩電流を測定することによって耐マイグレーション性を評価した。その結果、２００μＡの漏洩電流が流れるまでに要した時間は平均８０分であり、耐マイグレーション性に優れていた。
上記における比抵抗の測定及び耐マイグレーション性の評価については５個の試料の平均値を求めた。以下の実施例及び比較例についても同じである。
【００２５】
比較例１
実施例１で得た球形銀めっき銅粉を用い、偏平状への変形を省略した以外は実施例１と同様の工程を経て導電性ペーストを得た。球形銀めっき銅粉の長径／厚さは１、銀被覆面積は全表面積に対して全て９５％以上、銀層の厚さは０．１〜０．１５μｍの範囲で平均が０．１２μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層は明確に検知出来なかった。以下実施例１と同様の方法で特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均１２００μΩＣｍと極めて高く、２００μＡの漏洩電流が流れるまでに要した時間は平均１０分と短く、耐マイグレーション性に劣っていた。
【００２６】
比較例２
平均粒径が５μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）をあらかじめ長径／厚みが平均６になるように実施例１と同様の方法で変形し、しかる後実施例１と同様のめっき法で２０重量％の銀を被覆した。この銀めっき銅粉の銀被覆面積は全表面積に対して全て８５％以上、銀層の厚さは０．０３〜０．２μｍの範囲で平均が０．０８μｍ、貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層は明確に検知出来なかった。以下実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均８００μΩＣｍと高く、２００μＡの漏洩電流が流れるまでに要した時間は平均１０分と短く、耐マイグレーション性に劣っていた。
【００２７】
比較例３
実施例１で用いた導電性金属複合粉に代えて長径／厚さが平均３０の銀粉（徳力化学研究所製、商品名ＴＣＧ−１）を用いた以外は実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均８０μΩＣｍであったが、２００μＡの漏洩電流が流れるまでに要した時間は平均３０秒と極めて短く、耐マイグレーションに劣っていた。
【００２８】
比較例４
市販のＥＭＩシールド用銅ペーストを用いて実施例１と同様の特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均５００μΩＣｍと高く、２００μＡの漏洩電流が流れるまでに要した時間は平均４５分であった。
【００２９】
実施例２
平均粒径が６μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）に実施例１と同様のめっき法で３０重量％の銀を被覆して銀めっき銅粉を得、その後のＭＡ装置での処理時間を１時間とした以外は実施例１と同様の工程を経て導電性金属複合粉を得た。得られた導電性金属複合粉の粒子の長径は３〜１５μｍの範囲で平均が７μｍであり、また長径／厚さは２〜９の範囲で平均が２．５、銀被覆面積は全表面積に対して７５〜１００％の範囲で平均が９５％、銀層の厚さは０．０５〜０．２μｍの範囲で平均が０．１μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層の厚さは０．００１〜０．０１μｍの範囲で平均が０．００６μｍであり、表面貴金属層の厚さの１／５０〜１／８の範囲で平均が１／１６．７であった。以下実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均８０μΩＣｍ及び２００μＡの漏洩電流が流れるまでに要した時間は平均４０分であった。
【００３０】
実施例３
平均粒径が６μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）に実施例１と同様のめっき法で１０重量％の銀を被覆した以外は実施例１と同様の工程を経て導電性金属複合粉を得た。得られた導電性金属複合粉の粒子の長径は２〜３０μｍの範囲で平均が１５μｍであり、また長径／厚さは２〜１５の範囲で平均が６、銀被覆面積は全表面積に対して３０〜７０％の範囲で平均が５１％、銀層の厚さは０．０１〜０．０３μｍの範囲で平均が０．０２μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層の厚さは０．００１〜０．０２μｍの範囲で平均が０．０１μｍであり、表面貴金属層の厚さの１／１０〜２／３の範囲で平均が１／２であった。以下実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均１３５μΩＣｍ及び２００μＡの漏洩電流が流れるまでに要した時間は平均６０分であった。
【００３１】
実施例４
平均粒径が６μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）に実施例１と同様のめっき法で２重量％の銀を被覆して銀めっき銅粉を得、その後のＭＡ装置での処理時間を１時間とした以外は実施例１と同様の工程を経て導電性金属複合粉を得た。得られた導電性金属複合粉の粒子の長径は２〜２０μｍの範囲で平均が９μｍであり、また長径／厚さは２〜１３の範囲で平均が４、銀被覆面積は全表面積に対して１７〜７０％の範囲で平均が５５％、銀層の厚さは０．０００１〜０．０２μｍの範囲で平均が０．０１μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層の厚さは０．０００１〜０．００３μｍの範囲で平均が０．００２μｍであり、表面貴金属層の厚さの１／１５〜１の範囲で平均が１／５であった。以下実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均１１０μΩｃｍ及び２００μＡの漏洩電流が流れるまでに要した時間は平均１００分であった。
【００３２】
比較例５
平均粒径が６μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）に実施例１と同様のめっき法で１．５重量％の銀を被覆した以外は実施例１と同様の工程を経て導電性金属複合粉を得た。得られた導電性金属複合粉の粒子の長径は２〜３０μｍの範囲で平均が１５μｍであり、また長径／厚さは４〜１８の範囲で平均が６、銀被覆面積は全表面積に対して５〜３５％の範囲で平均が２０％、銀層の厚さは０．００００５〜０．００５μｍの範囲で平均が０．００３μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層の厚さは０．００００５〜０．００５μｍの範囲で平均が０．００３μｍであり、表面貴金属層の厚さの１／２〜１の範囲で平均が４／５であった。以下実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均４５０μΩｃｍと高く、２００μＡの漏洩電流が流れるまでに要した時間は平均９０分であった。
【００３３】
比較例６
平均粒径が６μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）に実施例１と同様のめっき法で３５重量％の銀を被覆した以外は実施例１と同様の工程を経て導電性金属複合粉を得た。得られた導電性金属複合粉の粒子の長径は２〜２５μｍの範囲で平均が１０μｍであり、また長径／厚さは３〜２０の範囲で平均が５、銀被覆面積は全表面積に対して６５〜９５％の範囲で平均が８０％、銀層の厚さは０．０３〜０．２μｍの範囲で平均が０．０６μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層の厚さは０．０００１〜０．００３μｍの範囲で平均が０．００１μｍであり、表面貴金属層の厚さの１／５００〜１／５０の範囲で平均が１／６０であった。以下実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均１３０μΩｃｍ及び２００μＡの漏洩電流が流れるまでに要した時間は平均１０分と短く耐マイグレーション性に劣っていた。
【００３４】
実施例５
実施例２で得た銀めっき銅粉（銀被覆量３０重量％）を２本のロール間で圧縮して粒子の長径が５〜５５μｍの範囲で平均が３０μｍであり、また長径／厚さが１５〜５０の範囲で平均が２７の導電性金属複合粉を得た。得られた導電性金属複合粉の銀被覆面積は全表面積に対して３５〜８０％の範囲で平均が５０％、銀層の厚さは０．００２〜０．０２μｍの範囲で平均が０．０１２５μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層の厚さは０．０００１〜０．０００５μｍの範囲で平均が０．０００２５μｍであり、表面貴金属層の厚さの１／２０〜１／１００の範囲で平均が１／５０であった。以下実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均１１５μΩｃｍ及び２００μＡの漏洩電流が流れるまでに要した時間は平均５０分であった。
【００３５】
実施例６
平均粒径が５μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）を蒸着装置内の皿状容器に保持し、皿状容器を回転させながら銀の量が２０重量％になるように銀の蒸着を行い銀蒸着銅粉を得た。
次にこの銀蒸着銅粉を実施例１と同様の工程を経て導電性金属複合粉を得た。得られた導電性金属複合粉の粒子の長径は３〜１５μｍの範囲で平均が７μｍであり、また長径／厚さは２〜１５の範囲で平均が６、銀被覆面積は全表面積に対して７５〜１００％の範囲で平均が９０％、銀層の厚さは０．０２〜０．１８μｍの範囲で平均が０．０４μｍ及び貴金属（銀）の割合が８０〜２０原子数％である貴金属と非貴金属（銅）とが混在する層の厚さは０．００１〜０．０５μｍの範囲で平均が０．０１５μｍであり、表面貴金属層の厚さの１／２０〜４／５の範囲で平均が１／２．７であった。以下実施例１と同様の工程を経て導電性ペーストを作製して特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均５５μΩｃｍ及び２００μＡの漏洩電流が流れるまでに要した時間は平均９０分であった。
【００３６】
実施例７
ビスフェノールＡ型液状エポキシ樹脂（油化シェル（株）製、商品名エピコート８２８）１００重量部及びノボラック型フェノールホルムアルデヒド樹脂（日立化成工業（株）製、商品名ＨＰ−６０７Ｎ）５５．８重量部を１１０℃で加熱混合して無溶剤の混合樹脂を得た。
次に実施例１で得た導電性金属複合粉１００重量部に対し、上記で得た無溶剤の混合樹脂８重量部及び硬化促進剤としてベンジルジメチルアミン０．０４重量部を加えて均一に混合して導電性ペーストを得た。以下実施例１と同様の方法で特性を評価した。その結果、導電性ペースト硬化物の比抵抗は平均８５μΩｃｍ及び２００μＡの漏洩電流が流れるまでに要した時間は平均８０分であった。
【００４１】
実施例８
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８３４）６０重量部及びビスフェノール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８２８）４０重量部を予め加温溶解させ、次いで室温（２０℃）に冷却した後、２エチル４メチルイミダゾール５重量部、エチルカルビトール２０重量部及びブチルセロソルブ２０重量部を加えて均一に混合して樹脂組成物とした。
【００４２】
平均粒径が７．２μｍの球形銅粉（日本アトマイズ加工（株）製、商品名ＳＦ−Ｃｕ）を希塩酸中に浸漬し、純水で洗浄した後、ＡｇＣＮ８０ｇ／水１ｋｇの混合液中で２５±５℃で２０分間撹拌しながら銀を置換めっきし、水洗、乾燥して銀めっき銅粉を得た。
【００４３】
次いで２リットルボールミル容器内に上記で得た銀めっき銅粉４００ｇと直径が５ｍｍのジルコニアボール３ｋｇを投入し、毎分６０回転の条件で３０分間回転させて該銀めっき銅粉を変形処理して導電性金属複合粉を得た。得られた導電性金属複合粉の粒子の長径は２〜２４μｍの範囲で平均が１１．５μｍであり、また長径／厚さは３〜１４の範囲で平均が９、銀被覆面積は全表面積に対して６０〜８５％の範囲で平均が７５％であった。
この後上記で得た樹脂組成物１４５ｇに上記で得た導電性金属複合粉２１５ｇを加えてらいかい機及び三本ロールで均一に混合分散して導電性ペーストを得た。なお導電性金属複合粉の含有量は、導電性ペーストの固形分に対して６０重量％であった。
【００４４】
次に上記で得た導電性ペーストで、厚さが１．６ｍｍで直径が０．８ｍｍのスルーホールを形成した紙フェノール銅張積層板（日立化成工業（株）製、商品名ＭＣＬ−４３７Ｆ）に図１に示すテストパターンを印刷すると共に、これをスルーホール１に充填したものを大気中で６０℃、３０分間さらに１６０℃、３０分間の条件で加熱処理して配線導体３を得た。なお図１において２は紙フェノール銅張積層板である。
【００４５】
得られた配線導体の抵抗を測定した結果、銅箔の抵抗を除いたスルーホール１の抵抗は５４穴の平均で２２ｍΩ／穴であり、平面に印刷して測定した比抵抗は９５μΩｃｍであった。また、隣り合うスルーホール１間の絶縁抵抗は１０８Ω以上であった。該配線導体の冷熱衝撃試験を実施した結果、スルーホール１の抵抗は平均で２６．２ｍΩ／穴であった。また該配線導体の湿中負荷試験を実施した結果、スルーホール１間の絶縁抵抗は１０８Ω以上であった。なお、冷熱衝撃試験は１２５℃、３０分〜−６５℃、３０分を１００サイクル行い、湿中負荷試験は４０℃、９０％ＲＨ中、隣り合うライン間に５０Ｖの電圧を印加して２０００時間保持した。さらに耐はんだ試験（２６０℃、１０秒、５回）を行ったが、抵抗変化率は３０％以内であった。
【００４６】
実施例９
実施例８で得た銀めっき銅粉２５０ｇと直径が５ｍｍのジルコニアボール５ｋｇを円筒状の２リットル容器内に投入し、振動ミルで１０分間振動させ、該銀めっき銅粉を変形処理して導電性金属複合粉を得た。得られた導電性金属複合粉の粒子の長径は３〜２５μｍの範囲で平均が１１．５μｍであり、また長径／厚さは２〜１２の範囲で平均が７、銀被覆面積は全表面積に対して６０〜８５％の範囲で平均が７０％であった。
この後実施例８で得た樹脂組成物１４５ｇに上記で得た導電性金属複合粉２４０ｇを加え、以下実施例８と同様の工程を経て導電性ペーストを得た。なお導電性金属複合粉の含有量は、導電性ペーストの固形分に対して６３重量％であった。
【００４７】
以下実施例８と同様の工程を経て配線導体を作製して特性を評価した。その結果、スルーホールの抵抗は５４穴の平均で２１．５ｍΩ／穴であり、平面に印刷して測定した比抵抗は１０２μΩｃｍであった。また、隣り合うスルーホール間の絶縁抵抗は１０８Ω以上であった。該配線導体の冷熱衝撃試験を実施した結果、スルーホールの抵抗は平均で２４．５ｍΩ／穴であり、湿中負荷試験の結果では、スルーホール間の絶縁抵抗は１０８Ω以上であった。さらに実施例８と同様の耐はんだ試験を行ったが、抵抗変化率は３０％以内であった。
【００４８】
比較例７
実施例８で得た樹脂組成物１４５ｇに実施例８で得た銀めっき銅粉１９５ｇを加え、以下実施例８と同様の工程を経て導電性ペーストを得た。なお銀被覆面積は全表面積に対して９３〜９９％の範囲で平均が９７％であった。また導電性金属複合粉の含有量は、導電性ペーストの固形分に対して５７重量％であった。
以下実施例８と同様の工程を経て配線導体を作製して特性を評価した。その結果、スルーホールの抵抗は５４穴の平均で２２８ｍΩ／穴であり、平面に印刷して測定した比抵抗は３５０μΩｃｍであり、隣り合うスルーホール間の絶縁抵抗は１０８Ω以上であった。また該配線導体の冷熱衝撃試験を実施した結果、スルーホールの抵抗は平均で２５１ｍΩ／穴であり、湿中負荷試験の結果では、スルーホール間の絶縁抵抗は１０８Ω以上であった。さらに実施例８と同様の耐はんだ試験を行ったところ、抵抗変化率は２００％であった。
【００４９】
実施例１０
実施例８で得た樹脂組成物１４５ｇに実施例８で得た導電性金属複合粉１９５ｇを加えてらいかい機及び三本ロールで均一に混合分散して導電性ペーストを得た。なお導電性金属複合粉の含有量は、導電性ペーストの固形分に対して６６．１重量％であった。
次に上記で得た導電性ペーストで、厚さが１．６ｍｍの紙フェノール銅張積層板（日立化成工業（株）製、商品名ＭＣＬ−４３７Ｆ）に図２に示すテストパターンを印刷し、これを大気中で６０℃、３０分間さらに１６０℃、３０分間の条件で加熱処理して配線導体３を形成した電磁波シールド材を得た。得られた電磁波シールド材の抵抗を測定した。その結果、比抵抗は３５μΩｃｍであり、シート抵抗は１３ｍΩ／□であった。また、冷熱試験を１２５℃、３０分〜−６５℃、３０分を１００サイクルの条件で行うと共に耐はんだ試験（２６０℃、１０秒、５回）を行ったが、ともに抵抗変化率は１０％以内であった。また、６０℃、９５％相対湿度で１０００時間保持した場合の抵抗変化率も１０％以内であった。
【００５０】
【発明の効果】
請求項１記載の導電性金属複合粉は、高導電性で、導電性と耐マイグレーション性に優れる。
請求項２記載の導電性金属複合粉は、請求項１記載の導電性金属複合粉の効果を奏し、特に耐マイグレーション性に優れる。
請求項３記載の導電性金属複合粉は、請求項１記載の導電性金属複合粉の効果を奏し、特に導電性と耐マイグレーション性に優れる。
請求項４記載の導電性金属複合粉は、請求項１記載の導電性金属複合粉の効果を奏し、特に導電性に優れる。
請求項５記載の方法により得られる導電性金属複合粉は、安価で、かつ高導電性で、耐マイグレーション性に優れる。
【図面の簡単な説明】
【図１】紙フェノール銅張積層板に導電性ペーストを印刷すると共にスルーホールに充填した状態を示す平面図である。
【図２】紙フェノール銅張積層板に導電性ペーストを印刷した電磁波シールド材の平面図である。
【符号の説明】
１ スルーホール
２ 紙フェノール銅張積層板
３ 配線導体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a conductive metal composite powder suitable for a conductive paste for forming an electric circuit and a method for producing the same.
[0002]
[Prior art]
Conventionally, as a method for forming a wiring conductor on an insulating substrate for mounting a wiring board or electronic component, a conductive metal powder such as gold, silver, palladium, copper, or aluminum, a binder such as a resin or glass frit And a method of forming a paste by adding or printing a conductive paste is generally known and applied to through-hole conduction, electrode formation, jumper wires, EMI shielding, etc. Yes.
Of the various conductive metal powders, gold is extremely expensive, so silver is often used as a conductive metal powder in fields where high conductivity is required, and copper in other fields.
[0003]
However, silver is expensive after gold and palladium, and when a DC voltage is applied in the presence of moisture, electrodeposition of silver called migration occurs on the electrodes and wiring conductors, and the electrodes or wirings are short-circuited. A serious problem arises.
In order to prevent migration of silver, a conductive material using an alloy of silver and palladium as a conductive metal powder is commercially available, but there is still a problem that it is extremely expensive.
[0004]
On the other hand, copper is cheap and migration is relatively difficult to occur. However, when the conductive paste is heated, the problem is that an oxide film is formed on the surface of the copper particles by air and oxygen in the binder to deteriorate the conductivity. There is. For this reason, measures such as applying a moisture-proof paint to the surface of the conductor or adding corrosion or antioxidant to the conductive material have been studied, but sufficient effects have not been obtained.
[0005]
In order to improve the oxidation resistance of copper and the migration resistance of silver, a method using silver-plated copper powder is disclosed in Japanese Patent Application Laid-Open No. 56-8892. However, this method has poor conductivity as compared with silver powder. Only a part of silver powder was replaced with copper powder. Further, as proposed in JP-A-3-247702, JP-A-4-268811, etc., there is a method of producing silver particles on the surface of copper by an atomizing method. Therefore, there is a problem that the cost is high, and the obtained powder is substantially spherical particles, so that the contact area between the powders is small and the resistance is high as compared with the flat or dendritic powder.
[0006]
[Problems to be solved by the invention]
The invention according to claim 1 provides a conductive metal composite powder that is conductive and excellent in conductivity and migration resistance.
In addition to the invention described in claim 1, the invention described in claim 2 provides a conductive metal composite powder that is particularly excellent in migration resistance.
In addition to the invention described in claim 1, the invention described in
In addition to the invention of claim 1, the invention of claim 4 provides a conductive metal composite powder that is particularly excellent in conductivity.
The invention according to claim 5 provides a method for producing a conductive metal composite powder that is inexpensive, highly conductive, and excellent in migration resistance.
[0007]
[Means for Solving the Problems]
In the present invention, 50% or more of the total surface area of the flat non-noble metal powder is coated with 2 to 30% by weight of noble metal with respect to the flat non-noble metal powder, and between the surface noble metal layer and the non-noble metal layer. A conductive metal composite powder comprising a layer in which noble metal and non-noble metal are mixed, wherein the layer in which noble metal and non-noble metal are mixed is 1/2 to 1/50 of the thickness of the surface noble metal layer. It relates to conductive metal composite powder.
Further, according to the present invention, in the conductive metal composite powder, the layer in which the noble metal and the non-noble metal are mixed is a conductive metal composite in which the noble metal is 80 to 20 atomic% and the non-noble metal is 20 to 80 atomic%. Regarding powder.
The present invention also relates to a conductive metal composite powder having a surface noble metal layer thickness of 0.01 to 0.2 μm in the conductive metal composite powder.
Moreover, this invention relates to the electroconductive metal composite powder whose major axis / thickness of this electroconductive metal composite powder is 2-30.
Further, the present invention provides a flat deformation and surface noble metal layer and non-noble metal by applying mechanical energy after coating the surface of the non-noble metal powder with 2 to 30% by weight of the noble metal powder. The present invention relates to a method for producing a conductive metal composite powder characterized in that a layer in which a noble metal and a non-noble metal are mixed is formed between the layers.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The flat shape in the present invention is a shape obtained by crushing a solid shape such as a spherical shape or a lump shape in one direction, and includes, for example, what is generally called a flake shape.
[0009]
The non-noble metal powder used in the present invention is a non-noble metal having conductivity from the viewpoint of low cost, and for example, copper, copper alloy, nickel or the like is used. The noble metal coated on the surface of the non-noble metal powder is preferably a noble metal such as gold, silver or platinum from the viewpoint of oxidation resistance and high conductivity.
[0010]
There is no particular limitation on the method for coating the surface of the non-noble metal powder on the surface, and it is preferable to use a plating method, a vapor deposition method, a mechano-fusion method for coating with mechanical energy, or the like.. sideThe area where the flat non-noble metal powder is covered with the noble metal (hereinafter simply referred to as “covered area”) is 50% or more of the total surface area of the flat non-noble metal powder, and the amount of noble metal used for this coating ( Hereinafter, the coating amount is simply 2 to 30% by weight with respect to the flat non-noble metal powder.sois there. When the coating area is less than 50% or the coating amount is less than 2% by weight, when the conductive paste is applied to a substrate or the like and heat-treated, the underlying flat non-noble metal powder is oxidized, resulting in poor conductivity. On the other hand, when the coating amount exceeds 30% by weight, the migration resistance deteriorates.
The covering area is determined as follows. That is, randomly pick up 5 or more particles of conductive metal composite powder, quantitatively analyze noble metals and non-noble metals with an Auger spectroscopic analyzer, calculate the proportion of noble metals, calculate the average value, and calculate this average value. Cover area.
The ratio of the non-noble metal to the noble metal is measured, for example, by taking out 1 g of the conductive metal composite powder, dissolving it with nitric acid, and measuring this solution using a chemical quantitative analysis, an atomic absorption analyzer or the like.
The covering area is 50% or more. However, it is preferable that a part of the surface of the non-noble metal powder is exposed in that a local battery is formed on the particles of the non-noble metal powder and elution of the noble metal can be suppressed. In particular, when the noble metal is silver, it is preferable to use a combination of non-noble metal powders such as copper and nickel because the silver migration is improved and an excellent effect is exhibited. The coating amount is preferably 7 to 25% by weight, more preferably 15 to 20% by weight.
[0011]
In the present invention, the layer in which the noble metal and the non-noble metal are mixed is a state in which both the noble metal used for forming the coating layer and the non-noble metal component of the base material layer are mixed. Excellent conductivity and migration resistance are exhibited when the thickness of the layer in which the non-noble metal is mixed is 1/2 to 1/50 of the thickness of the surface noble metal layer. When the thickness of the layer containing the noble metal and the non-noble metal exceeds 1/2 or less than 1/50 of the thickness of the surface noble metal layer, the conductivity tends to be remarkably deteriorated. The thickness of the layer in which the noble metal and the non-noble metal are mixed is more preferably 1/2 to 1/40, and further preferably 1/2 to 1/30 with respect to the thickness of the surface noble metal layer.
The thickness of the surface precious metal layer and the thickness of the precious metal / non-noble metal mixed layer are determined by taking out 5 or more particles of the conductive metal composite powder at random and simultaneously scraping the surface by ion sputtering. Three or more points are measured for one particle using an Auger spectroscopic analyzer to be analyzed, an average value for each thickness is obtained, and this average value is determined as each thickness.
[0012]
The layer in which the noble metal and the non-noble metal of the conductive metal composite powder according to the present invention are mixed contains 20 to 80 atom% of the non-noble metal with respect to 80 to 20 atom% of the noble metal. It is preferable at the point which shows migration property.
In addition, when the conductive metal composite powder according to the present invention is used as a paste and further screen-printed, the surface noble metal layer has a thickness of 0.01 to 0.2 μm. It is preferable because of its excellent migration property. When the thickness is less than 0.01 μm, the conductivity tends to deteriorate, and when the thickness exceeds 0.2 μm, the migration resistance tends to deteriorate.
[0013]
In the conductive metal composite powder according to the present invention, the length / thickness of the flat non-noble metal powder is preferably 2 to 30 in view of excellent conductivity and oxidation resistance, and preferably 5 to 20. Is more preferable, and it is further more preferable that it is 7-15. If the major axis / thickness of the flat non-noble metal powder is less than 2, the contact between the powders becomes almost point contact, so there is a tendency to increase resistance, and if it exceeds 30, the total surface area even if the precious metal is coated by 30% by weight. It is difficult to produce a material coated with 50% or more of this, and when a conductive paste is applied to a substrate or the like and heat-treated, the underlying non-noble metal powder tends to oxidize and the conductivity tends to deteriorate. is there.
The major axis is preferably 100 μm or less in absolute value, more preferably 50 μm or less, and even more preferably 30 μm or less. As for the long diameter / thickness of the conductive metal composite powder, take an SEM photo of the conductive metal composite powder using a scanning electron microscope, and randomly select 30 or more particles of the conductive metal composite powder. The major axis / thickness is measured, the average value is obtained, and this average value is taken as the major axis / thickness of the conductive metal composite powder.
[0014]
About the manufacturing method of the electroconductive metal composite powder of this invention, there is no restriction | limiting in particular about the average particle diameter and shape of the non-noble metal powder used as a base material. About precious metal coating methodIsFrom the viewpoint of balance between cost and characteristics, a method of plating or vapor-depositing silver on copper powder having an average particle size of 1 to 30 μm or less determined by a general particle size distribution measurement method such as a laser method or a sedimentation method is preferable.
[0015]
In the present invention, the conductive metal composite powder deformed into a flat shape is coated with a noble metal on the surface of the non-noble metal powder, and then compressed into a hard material at high speed by a mechanical alloying device, a dry ball milling device, a roll or the like. Apply mechanical energy using a device that spraysRukoAnd can be manufactured.
Add mechanical energy to non-noble metal powder coated with precious metalRukoAs a result, voids (voids) existing in the noble metal or between the surface noble metal layer and the non-noble metal layer are eliminated, and the noble metal layer covered thereby is densified and its conductivity is increased. Further, at this time, a thin region in which noble metal and non-noble metal are mixed is formed between the surface noble metal layer and the non-noble metal layer, whereby the contact resistance between the surface noble metal layer and the non-noble metal layer can be reduced.
[0016]
The binder added to produce the conductive paste using the conductive metal composite powder according to the present invention is epoxy resin, phenol resin, unsaturated polyester resin, saturated polyester resin, polyamide resin, polyimide resin, polyamideimide resin, Examples include organic binders such as acrylic resins or inorganic binders such as glass frit, and further curing accelerators and solvents are added as necessary. Examples of curing accelerators include imidazoles and amines, and solvents. Examples thereof include butyl cellosolve, terpineol, ethylene carbitol, carbitol acetate, and the like.
The conductive paste is obtained by adding a binder and, if necessary, a curing accelerator and a solvent to the conductive metal composite powder, and uniformly mixing the mixture with a cracker, roll, kneader or the like. The content of the binder is preferably 5 to 30% by weight and more preferably 8 to 16% by weight with respect to the conductive paste. A curing accelerator and a solvent are added as necessary. When added, the content of the curing accelerator is preferably 0.01 to 1% by weight with respect to the conductive paste, and 0.02 to 0.0. More preferably, it is 05 weight%. The solvent is preferably 3 to 50% by weight, more preferably 10 to 30% by weight based on the conductive paste.
[0017]
The conductive paste using the conductive metal composite powder according to the present invention is most suitable as a material for forming a wiring conductor by coating, printing, and potting on various substrates and various films used as insulating base materials. It can be used for forming holes, holes, electrodes, jumper wires, EMI shields, and the like. It can also be used as a conductive adhesive for connecting electronic components such as resistance elements, chip resistors, chip capacitors, etc., and insulating base materials, and lead-free solder substitutes.
[0018]
Examples of the various substrates include paper phenol substrates, glass epoxy substrates, enamel substrates, ceramic substrates, and the like, and various films include polyethylene, polycarbonate, vinyl chloride, polystyrene, polyethylene terephthalate, polyphenylene sulfide, and polyether ketone. And flexible resin films such as polyetherimide and polyimide.
The insulating base material may be formed by previously forming a conductor or a part of a resistor on the surface or through hole by a method such as plating, printing, vapor deposition, etching or the like.
[0019]
【Example】
Examples of the present invention will be described below.
Example 1
Spherical copper powder having an average particle size of 5 μm (manufactured by Nippon Atomizing Co., Ltd., trade name SF-Cu) is removed with an acidic cleaner (manufactured by Nihon McDermid Co., Ltd., trade name L-5B), washed with water, and water 1 Displacement plating was performed in a plating bath containing 20 g of AgCN and 10 g of NaCN per liter so that the amount of silver was 20 wt% with respect to the spherical copper powder, washed with water, and dried to obtain silver-plated copper powder.
[0020]
Next, this silver-plated copper powder was put into an MA (mechanical alloying) apparatus and subjected to deformation treatment under the following conditions. This apparatus moves the ball by rotating the screw, and the effective volume of the container into which the ball and the powder to be processed are charged is 1.1 liters. 4 kg of zirconia balls (diameter 10 mm) and 200 g of silver-plated copper powder are put into the apparatus, the screw rotation speed is 90 rpm, and the internal pressure of the container is 2 × 10.-5It rotated for 2 hours on the conditions of torr, and obtained the electroconductive metal composite powder (flat silver plating copper powder).
[0021]
Next, an SEM photograph of the conductive metal composite powder obtained above was taken using a scanning electron microscope, 30 particles of the conductive metal composite powder were selected, and the major axis / thickness was measured. The average was 6. The major axis was in the range of 2 to 30 μm and the average was 15 μm.
In addition, 5 particles of the conductive metal composite powder were taken out at random, and when the noble metal and non-noble metal were quantitatively analyzed with a scanning Auger electron spectrometer, the silver coating area was examined. In the range, the average was 70%.
Further, five particles of conductive metal composite powder were taken at random, and the surface was scraped by ion sputtering, and at the same time, three points were measured for each particle with a scanning Auger electron spectroscopic analyzer. The thickness of the layer is in the range of 0.02 to 0.15 μm, the average is 0.045 μm, and the ratio of the precious metal (silver) is 80 to 20 atomic%. The average was 0.01 μm in the range of 0.001 to 0.05 μm, and the average was 1 / 4.5 in the range of 1/20 to 1/2 of the thickness of the surface noble metal layer.
In the following examples and comparative examples, the measurement was performed in the same manner as described above.
[0022]
Novolak type phenolic resin with respect to 100 parts by weight of the conductive metal composite powder
(Gunei Chemical Industry Co., Ltd., trade name PS-2607) 15 parts by weight and 15 parts by weight of butyl cellosolve as a solvent were added and mixed uniformly to obtain a conductive paste.
[0023]
Next, the conductive paste was passed through a 200-mesh screen on the top surface of the laminate from which the copper foil of the paper phenol copper clad laminate (trade name MCL-437F, manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 1.6 mm was removed. A test pattern having a length of 0.4 mm and a length of 100 mm was printed, and heat treatment was performed in air at 150 ° C. for 30 minutes to obtain a wiring conductor. The specific resistance of the cured conductive paste in the obtained wiring conductor was 75 μΩCm on average, indicating a conductivity comparable to a silver paste described later.
[0024]
On the other hand, a conductive paste is printed on a glass plate by the same method as described above so that the electrodes are 2 mm apart from each other on the glass plate, and cured by heating at 150 ° C. for 30 minutes in the atmosphere. To obtain an electrode. Next, a filter paper cut to a width of 2 mm is placed between the electrodes, 0.5 cc of ion exchange water is dropped on the filter paper, a DC voltage of 20 V is applied between the electrodes, and the elapsed time and the leakage current between the electrodes are measured. Migration resistance was evaluated. As a result, the average time required for the leakage current of 200 μA to flow was 80 minutes, and the migration resistance was excellent.
About the measurement of specific resistance in the above, and evaluation of migration resistance, the average value of five samples was calculated | required. The same applies to the following examples and comparative examples.
[0025]
Comparative Example 1
A conductive paste was obtained through the same steps as in Example 1 except that the spherical silver-plated copper powder obtained in Example 1 was used and the deformation into a flat shape was omitted. The major axis / thickness of the spherical silver-plated copper powder is 1, the silver coverage is 95% or more of the total surface area, the thickness of the silver layer is in the range of 0.1 to 0.15 μm, the average is 0.12 μm, and noble metal A layer in which noble metal and non-noble metal (copper) in which the ratio of (silver) is 80 to 20 atomic% was mixed could not be detected clearly. The characteristics were evaluated in the same manner as in Example 1 below. As a result, the specific resistance of the cured conductive paste was as extremely high as 1200 μΩCm on average, and the time required for the leakage current of 200 μA to flow was as short as 10 minutes on average, indicating poor migration resistance.
[0026]
Comparative Example 2
Spherical copper powder having an average particle size of 5 μm (trade name SF-Cu, manufactured by Nippon Atomizing Co., Ltd.) was previously deformed in the same manner as in Example 1 so that the average length / thickness was 6, and then implemented. 20% by weight of silver was coated by the same plating method as in Example 1. The silver-coated copper powder has a silver coating area of 85% or more with respect to the total surface area, the thickness of the silver layer is in the range of 0.03 to 0.2 μm, the average is 0.08 μm, and the ratio of noble metal (silver) is 80 A layer in which noble metal and non-noble metal (copper) of ˜20 atomic% were mixed could not be detected clearly. A conductive paste was prepared through the same steps as in Example 1 and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was as high as 800 μΩCm on average, and the time required for a leakage current of 200 μA to flow was as short as 10 minutes on average, indicating poor migration resistance.
[0027]
Comparative Example 3
It replaced with the electroconductive metal composite powder used in Example 1, and passed through the process similar to Example 1 except having used silver powder (Tokuriku Chemical Laboratory make, brand name TCG-1) whose average length / thickness is 30. A conductive paste was prepared and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was an average of 80 μΩCm, but the time required for the 200 μA leakage current to flow was as extremely short as an average of 30 seconds, indicating poor migration resistance.
[0028]
Comparative Example 4
The same characteristics as in Example 1 were evaluated using a commercially available copper paste for EMI shielding. As a result, the specific resistance of the cured conductive paste was as high as 500 μΩCm on average, and the time required for the leakage current of 200 μA to flow was an average of 45 minutes.
[0029]
Example 2
Spherical copper powder having an average particle diameter of 6 μm (product name SF-Cu, manufactured by Nippon Atomizing Co., Ltd.) is coated with 30% by weight of silver by the same plating method as in Example 1 to obtain silver-plated copper powder. A conductive metal composite powder was obtained through the same steps as in Example 1 except that the treatment time in the subsequent MA apparatus was 1 hour. The major axis of the particles of the obtained conductive metal composite powder is 3 to 15 μm and the average is 7 μm. The major axis / thickness is 2 to 9 and the average is 2.5, and the silver covered area is the total surface area. On the other hand, the average is 95% in the range of 75 to 100%, the thickness of the silver layer is in the range of 0.05 to 0.2 μm, the average is 0.1 μm, and the ratio of noble metal (silver) is 80 to 20 atomic% The thickness of the layer in which a certain noble metal and non-noble metal (copper) are mixed is 0.006 μm in average in the range of 0.001 to 0.01 μm, and is 1/50 to 1/8 of the thickness of the surface noble metal layer. The average in the range was 1 / 16.7. A conductive paste was prepared through the same steps as in Example 1 and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was an average of 80 minutes for the leakage current of 80 μΩCm and 200 μA to flow.
[0030]
Example 3
The same as in Example 1 except that spherical copper powder having an average particle size of 6 μm (trade name SF-Cu, manufactured by Nippon Atomizing Co., Ltd.) was coated with 10% by weight of silver by the same plating method as in Example 1. Through the steps, a conductive metal composite powder was obtained. The major axis of the particles of the obtained conductive metal composite powder is 2 to 30 μm and the average is 15 μm. The major axis / thickness is 2 to 15 and the average is 6, and the silver coating area is based on the total surface area. Noble metal with an average of 51% in the range of 30 to 70%, a thickness of the silver layer in the range of 0.01 to 0.03 μm, an average of 0.02 μm, and a ratio of noble metal (silver) of 80 to 20 atomic% And non-noble metal (copper) are mixed in a thickness range of 0.001 to 0.02 μm and an average of 0.01 μm, and within a range of 1/10 to 2/3 of the surface noble metal layer thickness. The average was 1/2. A conductive paste was prepared through the same steps as in Example 1 and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was an average of 135 minutes for the leakage current of 135 μΩCm and 200 μA to flow.
[0031]
Example 4
Spherical copper powder having an average particle diameter of 6 μm (trade name SF-Cu, manufactured by Nippon Atomizing Co., Ltd.) is coated with 2% by weight of silver by the same plating method as in Example 1 to obtain silver-plated copper powder. A conductive metal composite powder was obtained through the same steps as in Example 1 except that the subsequent processing time in the MA apparatus was 1 hour. The average diameter of the particles of the obtained conductive metal composite powder is 2 to 20 μm and the average is 9 μm, and the average length / thickness is 2 to 13 and the average is 4, and the silver covered area is based on the total surface area. Noble metal having an average of 55% in the range of 17 to 70%, an average thickness of 0.0001 to 0.02 μm in the range of 0.0001 to 0.02 μm, and a ratio of noble metal (silver) of 80 to 20 atomic% The thickness of the layer containing non-noble metal (copper) is 0.002 μm in the range of 0.0001 to 0.003 μm, and the average is in the range of 1/15 to 1 of the thickness of the surface noble metal layer. It was 1/5. A conductive paste was prepared through the same steps as in Example 1 and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was an average of 110 μΩcm and the time required for a leakage current of 200 μA to flow was an average of 100 minutes.
[0032]
Comparative Example 5
Example 1 except that spherical copper powder having an average particle size of 6 μm (trade name SF-Cu, manufactured by Nippon Atomizing Co., Ltd.) was coated with 1.5% by weight of silver by the same plating method as Example 1. A conductive metal composite powder was obtained through the same process. The major axis of the particles of the obtained conductive metal composite powder is 2 to 30 μm and the average is 15 μm. The major axis / thickness is 4 to 18 and the average is 6, and the silver coating area is based on the total surface area. Noble metal having an average of 20% in the range of 5 to 35%, an average thickness of 0.003 μm in the range of 0.00005 to 0.005 μm, and a ratio of noble metal (silver) of 80 to 20 atomic% The thickness of the layer containing non-noble metal (copper) is 0.003 μm in the range of 0.00005 to 0.005 μm, and the average is in the range of 1/2 to 1 of the thickness of the surface noble metal layer. 4/5. A conductive paste was prepared through the same steps as in Example 1 and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was as high as 450 μΩcm on average, and the time required for the leakage current of 200 μA to flow was 90 minutes on average.
[0033]
Comparative Example 6
The same as in Example 1 except that spherical copper powder having an average particle size of 6 μm (trade name SF-Cu, manufactured by Nippon Atomizing Co., Ltd.) was coated with 35% by weight of silver by the same plating method as in Example 1. Through the steps, a conductive metal composite powder was obtained. The average diameter of the particles of the obtained conductive metal composite powder is 2 to 25 μm, the average is 10 μm, the long diameter / thickness is 3 to 20 and the average is 5, and the silver covered area is based on the total surface area. An average of 80% in the range of 65 to 95%, a thickness of the silver layer of 0.03 to 0.2 μm, an average of 0.06 μm, and a ratio of noble metal (silver) of 80 to 20 atomic% And the non-noble metal (copper) mixed layer has a thickness in the range of 0.0001 to 0.003 μm and an average of 0.001 μm, in the range of 1/500 to 1/50 of the thickness of the surface noble metal layer. The average was 1/60. A conductive paste was prepared through the same steps as in Example 1 and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was as short as 10 minutes on average until the leakage current of 130 μΩcm and 200 μA on average was inferior in migration resistance.
[0034]
Example 5
The silver-plated copper powder (silver coverage 30% by weight) obtained in Example 2 was compressed between two rolls, and the average particle diameter was in the range of 5 to 55 μm and the average was 30 μm. Conductive metal composite powder having an average of 27 in the range of 15 to 50 was obtained. The obtained conductive metal composite powder has a silver coating area of 35 to 80% with respect to the total surface area and an average of 50%, and the silver layer has a thickness of 0.002 to 0.02 μm with an average of 0.00. The thickness of the layer in which noble metal and non-noble metal (copper) having a ratio of 0125 μm and noble metal (silver) of 80 to 20 atomic% is in the range of 0.0001 to 0.0005 μm and the average is 0.00025 μm The average was 1/50 in the range of 1/20 to 1/100 of the thickness of the surface noble metal layer. A conductive paste was prepared through the same steps as in Example 1 and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was an average of 115 μΩcm and the time required for the leakage current of 200 μA to flow was an average of 50 minutes.
[0035]
Example 6
A spherical copper powder (product name SF-Cu, manufactured by Nippon Atomizing Co., Ltd.) having an average particle diameter of 5 μm is held in a dish-shaped container in a vapor deposition apparatus, and the amount of silver is 20% by weight while rotating the dish-shaped container. Silver deposition was performed to obtain a silver-deposited copper powder.
Next, this silver vapor-deposited copper powder was subjected to the same steps as in Example 1 to obtain a conductive metal composite powder. The average particle diameter of the obtained conductive metal composite powder is 3 to 15 μm and the average is 7 μm, the long diameter / thickness is 2 to 15 and the average is 6, and the silver-coated area is based on the total surface area. Noble metal having an average of 90% in the range of 75 to 100%, a thickness of the silver layer of 0.02 to 0.18 μm, an average of 0.04 μm, and a ratio of noble metal (silver) of 80 to 20 atomic% The thickness of the layer in which non-noble metal (copper) is mixed is 0.001 to 0.05 μm in average and 0.015 μm in average, and is in the range of 1/20 to 4/5 of the thickness of the surface noble metal layer The average was 1 / 2.7. A conductive paste was prepared through the same steps as in Example 1 and the characteristics were evaluated. As a result, the specific resistance of the cured conductive paste was an average of 55 μΩcm and the time required for a leakage current of 200 μA to flow was an average of 90 minutes.
[0036]
Example 7
100 parts by weight of bisphenol A type liquid epoxy resin (trade name Epicoat 828, manufactured by Yuka Shell Co., Ltd.) and 55.8 parts by weight of novolac type phenol formaldehyde resin (trade name HP-607N, manufactured by Hitachi Chemical Co., Ltd.) Solvent-free mixed resin was obtained by heating and mixing at 110 ° C.
Next, to 100 parts by weight of the conductive metal composite powder obtained in Example 1, 8 parts by weight of the solvent-free mixed resin obtained above and 0.04 parts by weight of benzyldimethylamine as a curing accelerator were added and mixed uniformly. As a result, a conductive paste was obtained. The characteristics were evaluated in the same manner as in Example 1 below. As a result, the specific resistance of the cured conductive paste was 85 minutes on average, and the average time required for leakage current of 200 μA to flow was 80 minutes.
[0041]
Example8
60 parts by weight of bisphenol A type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., trade name Epicoat 834) and 40 parts by weight of bisphenol A type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epicoat 828) are added in advance. After dissolving in warm and then cooling to room temperature (20 ° C.), 5 parts by weight of 2-ethyl 4-methylimidazole, 20 parts by weight of ethyl carbitol and 20 parts by weight of butyl cellosolve were added and mixed uniformly to obtain a resin composition.
[0042]
Spherical copper powder having an average particle size of 7.2 μm (trade name SF-Cu, manufactured by Nippon Atomizing Co., Ltd.) is immersed in diluted hydrochloric acid, washed with pure water, and then mixed in a mixed solution of 80 g AgCN / 1 kg water. Silver was substituted and plated while stirring at ± 5 ° C. for 20 minutes, washed with water and dried to obtain silver-plated copper powder.
[0043]
Next, 400 g of the silver-plated copper powder obtained above and 3 kg of zirconia balls having a diameter of 5 mm are put into a 2 liter ball mill container, and the silver-plated copper powder is deformed by rotating for 30 minutes at 60 rpm. Conductive metal composite powder was obtained. The average length of the particles of the obtained conductive metal composite powder is 11.5 μm in the range of 2 to 24 μm, and the average of the long diameter / thickness is 9 in the range of 3 to 14 and the silver covered area is the total surface area. On the other hand, the average was 75% in the range of 60 to 85%.
Thereafter, 215 g of the conductive metal composite powder obtained above was added to 145 g of the resin composition obtained above, and the mixture was uniformly mixed and dispersed with a screening machine and three rolls to obtain a conductive paste. In addition, content of electroconductive metal composite powder was 60 weight% with respect to solid content of the electroconductive paste.
[0044]
Next, a paper phenol copper-clad laminate (made by Hitachi Chemical Co., Ltd., trade name MCL-437F) in which through holes having a thickness of 1.6 mm and a diameter of 0.8 mm were formed using the conductive paste obtained above. A test pattern shown in FIG. 1 was printed, and the one filled with the through hole 1 was heat-treated in the atmosphere at 60 ° C. for 30 minutes and further at 160 ° C. for 30 minutes to obtain a
[0045]
As a result of measuring the resistance of the obtained wiring conductor, the resistance of the through hole 1 excluding the resistance of the copper foil was 22 mΩ / hole on the average of 54 holes, and the specific resistance measured by printing on a plane was 95 μΩcm. . The insulation resistance between adjacent through holes 1 is 108It was more than Ω. As a result of the thermal shock test of the wiring conductor, the resistance of the through hole 1 was 26.2 mΩ / hole on average. In addition, as a result of the moisture load test of the wiring conductor, the insulation resistance between the through holes 1 was 108It was more than Ω. In addition, the thermal shock test is performed at 125 ° C., 30 minutes to −65 ° C., 30 minutes for 100 cycles, and the humidity load test is performed at 40 ° C. and 90% RH, applying a voltage of 50 V between adjacent lines for 2000 hours. Retained. Further, a solder resistance test (260 ° C., 10 seconds, 5 times) was conducted, but the resistance change rate was within 30%.
[0046]
Example9
Example8250 g of the silver-plated copper powder obtained in 1 above and 5 kg of zirconia balls having a diameter of 5 mm are put into a cylindrical 2 liter container, vibrated with a vibration mill for 10 minutes, and the silver-plated copper powder is deformed to form a conductive metal composite. I got a powder. The average particle diameter of the obtained conductive metal composite powder is 3 to 25 μm and the average is 11.5 μm, and the average length / thickness is 2 to 12 and the average is 7, and the silver covered area is the total surface area. On the other hand, the average was 70% in the range of 60 to 85%.
Examples after this8240 g of the conductive metal composite powder obtained above was added to 145 g of the resin composition obtained in the above, and the following examples8A conductive paste was obtained through the same steps as described above. In addition, content of electroconductive metal composite powder was 63 weight% with respect to solid content of the electroconductive paste.
[0047]
Examples below8Wiring conductors were fabricated through the same steps as described above and their characteristics were evaluated. As a result, the resistance of the through holes was 21.5 mΩ / hole on the average of 54 holes, and the specific resistance measured by printing on a flat surface was 102 μΩcm. Also, the insulation resistance between adjacent through holes is 108It was more than Ω. As a result of the thermal shock test of the wiring conductor, the resistance of the through hole is 24.5 mΩ / hole on the average, and the result of the moisture load test shows that the insulation resistance between the through holes is 108It was more than Ω. Further examples8The same solder resistance test was conducted, but the rate of change in resistance was within 30%.
[0048]
Comparative Example 7
Example8145 g of the resin composition obtained in Example8195 g of silver-plated copper powder obtained in 18A conductive paste was obtained through the same steps as described above. The silver coating area was in the range of 93 to 99% with respect to the total surface area, and the average was 97%. Moreover, content of electroconductive metal composite powder was 57 weight% with respect to solid content of the electroconductive paste.
Examples below8Wiring conductors were fabricated through the same steps as described above and their characteristics were evaluated. As a result, the through-hole resistance is 228 mΩ / hole on an average of 54 holes, the specific resistance measured by printing on a flat surface is 350 μΩcm, and the insulation resistance between adjacent through-holes is 108It was more than Ω. In addition, as a result of the thermal shock test of the wiring conductor, the resistance of the through hole is 251 mΩ / hole on average, and the result of the moisture load test shows that the insulation resistance between the through holes is 108It was more than Ω. Further examples8When the same solder resistance test was performed, the rate of change in resistance was 200%.
[0049]
Example10
Example8145 g of the resin composition obtained in Example8195 g of the conductive metal composite powder obtained in the above was added, and the mixture was uniformly mixed and dispersed with a screening machine and three rolls to obtain a conductive paste. In addition, content of electroconductive metal composite powder was 66.1 weight% with respect to solid content of the electroconductive paste.
Next, with the conductive paste obtained above, a test pattern shown in FIG. 2 is printed on a paper phenol copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., trade name MCL-437F) having a thickness of 1.6 mm. This was heat-treated in the atmosphere at 60 ° C. for 30 minutes and further at 160 ° C. for 30 minutes to obtain an electromagnetic wave shielding material on which the
[0050]
【The invention's effect】
The conductive metal composite powder according to claim 1 is highly conductive and excellent in conductivity and migration resistance.
The conductive metal composite powder according to claim 2 exhibits the effect of the conductive metal composite powder according to claim 1, and is particularly excellent in migration resistance.
The conductive metal composite powder according to claim 3 exhibits the effect of the conductive metal composite powder according to claim 1, and is particularly excellent in conductivity and migration resistance.
The conductive metal composite powder according to claim 4 exhibits the effect of the conductive metal composite powder according to claim 1, and is particularly excellent in conductivity.
The conductive metal composite powder obtained by the method of claim 5 is inexpensive, highly conductive, and excellent in migration resistance.
[Brief description of the drawings]
FIG. 1 is a plan view showing a state in which a conductive paste is printed on a paper phenol copper-clad laminate and filled in through-holes.
FIG. 2 is a plan view of an electromagnetic wave shielding material obtained by printing a conductive paste on a paper phenol copper-clad laminate.
[Explanation of symbols]
1 Through hole
2 Paper phenolic copper clad laminate
3 Wiring conductor
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP02076496A JP3618441B2 (en) | 1995-02-13 | 1996-02-07 | Conductive metal composite powder and manufacturing method thereof |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2326195 | 1995-02-13 | ||
| JP2326095 | 1995-02-13 | ||
| JP7-23260 | 1995-02-13 | ||
| JP7-23261 | 1995-02-13 | ||
| JP02076496A JP3618441B2 (en) | 1995-02-13 | 1996-02-07 | Conductive metal composite powder and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08335406A JPH08335406A (en) | 1996-12-17 |
| JP3618441B2 true JP3618441B2 (en) | 2005-02-09 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP02076496A Expired - Lifetime JP3618441B2 (en) | 1995-02-13 | 1996-02-07 | Conductive metal composite powder and manufacturing method thereof |
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| JP (1) | JP3618441B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4182009B2 (en) * | 2003-03-31 | 2008-11-19 | Ｔｄｋ株式会社 | Conductive particles, conductive paste, electronic component, multilayer ceramic capacitor and manufacturing method thereof |
| JP4867948B2 (en) * | 2003-03-31 | 2012-02-01 | Ｔｄｋ株式会社 | Conductive particles, conductive paste, electronic component, multilayer ceramic capacitor and manufacturing method thereof |
| JP4583147B2 (en) * | 2004-11-19 | 2010-11-17 | 三井金属鉱業株式会社 | Conductive composite powder and method for producing the same |
| WO2015104986A1 (en) * | 2014-01-08 | 2015-07-16 | 日東電工株式会社 | Film-like adhesive, dicing tape with film-like adhesive, method for manufacturing semiconductor device, and semiconductor device |
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1996
- 1996-02-07 JP JP02076496A patent/JP3618441B2/en not_active Expired - Lifetime
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| Publication number | Publication date |
|---|---|
| JPH08335406A (en) | 1996-12-17 |
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