JP3797786B2 - Copper alloy for electrical and electronic parts - Google Patents

Description

【００２９】
【表２】

【００３０】
【表３】

【００３１】
【表４】

【００３２】
この鋳塊を９３０℃に１時間加熱後、厚さ１５ｍｍまで熱間圧延して、７５０℃以上で熱延を終了し、水冷した。なお、Ｍｇ含有量が１．５％を越えるＮｏ．１８合金、Ｓｎ含有量が８％を越えるＮｏ．１９合金及びＰの含有量の多いＮｏ．２１合金は、熱延割れのおそれがあるため、均質化のために７００℃で１時間加熱後、７５０〜８５０℃に昇温し、熱間圧延を行った。
Ｎｏ．１６、Ｎｏ．１９及びＮｏ．２１合金は熱延途中で割れが発生し、厚さ１５ｍｍの状態でその後の冷延が不可能と思われたため、以後の工程を適用しなかった。また、Ｎｏ．２３合金は熱延中端面部において軽い耳割れが発生したが、耳割れ部を除去してその後の工程を適用した。
【００３３】
熱延材は、表面の酸化スケールを機械的に除去し、０．３５７ｍｍｔまで冷間圧延した。ただし、Ｎｏ．１８は冷延途中で耳割れが激しくなったため圧延を中止し、以後の工程を適用しなかった。その後、溶体化のために６５０〜８５０℃に２０秒間加熱した後、水中急冷した。
さらに、表面の酸化膜を酸洗除去後、厚さ減少率３０％の冷間圧延を行って板厚０．２５ｍｍとし、４４０〜５００℃で２時間の熱処理を行った。熱処理後の材料は表面の酸化膜を酸洗により除去し、試験に供した。
以下、この実施例で行った合金元素等の分析方法及び合金特性の試験方法について説明する。
【００３４】
＜合金元素の含有量とガス量の分析＞
［合金元素］
薄板より試料を採取し、十分に脱脂を行って、ＪＩＳに規定されている方法（Ｚｎ、Ｍｎ、Ｎｉ、Ｆｅ、Ｃｏ、Ｃｒ、Ｐ、Ｓｉ、Ａｌ、Ｓｅ、Ｔｅ、Ｐｂ、Ａｓ）、ＩＣＰ−ＭＳ、ＧＤ−ＭＳ、原子吸光法などを用いて分析した。なお、各元素について２回分析を行い、その平均値を含有量とした。
［ガス］
薄板より試料を採取し、塩酸中で電解研磨して表面の酸化膜を十分除去してから、分析を行った。
このうち酸素は、ＪＩＳ−Ｈ１０６７に規定されている方法（不活性ガス融解赤外線吸収法）で測定した。本法では、酸化物も融解する温度まで加熱して測定するため、測定される酸素量は銅合金中に固溶している酸素と、銅及び／又は他の元素と酸化物を形成している酸素の和となる。各試料について３回測定し、それらの平均値を測定値として用いた。
水素は、ＪＩＳ−Ｚ２６１４に規定されている方法で測定した。各試料について３回測定し、それらの平均値を測定値として用いた。
【００３５】
＜試験方法＞
［機械的性質］
試験片の長手方向を圧延方向に平行にしたＪＩＳ５号試験片を加工し、引張り強さと伸びを測定した。試験片の数は各試料３個ずつとし、それらの測定値の平均値を測定結果とした。
［導電率］
ＪＩＳＨ０５０５に規定されている方法に基づき、測定には横川電機製ダブルブリッジ５７５２を用いた。試験片は各試料２個ずつとし、それらの測定値の平均値を測定結果とした。
［ばね限界値］
ＪＩＳＨ３１３０に基づき、モーメント式試験により室温における永久たわみ量を測定し、Ｋｂ0.1を算出した。試験片の長手方向は圧延方向に平行とした。試験片は各試料１０個ずつとし、それらの測定値の平均値を測定結果とした。
［応力緩和特性］
【００３６】
図１及び図２に示すように、幅１０ｍｍの試験片１を片持ち梁式にて、長さ（ｌ）８０ｍｍの位置に試験片の耐力の８０％の曲げ応力を付加し、応力を付加した状態で１６０℃で１０００時間保持した後応力を除去した。応力を負荷したときの負荷点での試験片のたわみ量（δ：１０ｍｍ）と応力を除去したときの変位量（ε1）を測定し、次式によって応力緩和率を測定した。各試料から試験片を１０個ずつ採取し、それらの測定値の平均値を測定結果として用いた。
応力緩和率（％）＝（ε1／δ）×１００
なお、曲げ応力（σ）は次式によって算出される。
σ＝（３×Ｅ×ｔ×δ）／（２×ｌ²）
ただし、
σ：曲げ応力＝試験片の耐力×０．８
Ｅ：試験片のヤング率（Ｎ／ｍｍ²）
ｔ：試験片の板厚＝０．２５ｍｍ
【００３７】
［結晶粒径］
結晶粒径は圧延方向に平行な板断面において板厚方向の結晶粒径をＪＩＳ−Ｈ０５０１に規定する切断法で測定する。各試料から試験片を５個ずつ採取し、各試験片について３視野ずつ光学顕微鏡写真を撮影した（倍率１００〜２００倍）。撮影写真に対して、切断法による測定を行い、１５個のデータの平均値を結晶粒径とした。
［Ｓｎ及びＳｎ合金めっきの耐熱剥離性］
本発明の合金においては、Ｓｎめっき及びＳｎ合金めっきのどちらを行っても同様な結果が得られるため、本実施例においてははんだめっきを行って耐熱剥離性を調査した。幅１０ｍｍ、長さ５０ｍｍの試験片を各試料から１０個ずつ採取した。
はんだめっきとしては、アルカノールスルフォン酸第一錫１９３ｇ／ｌ、アルカノールスルフォン酸鉛３．５ｇ／ｌ、アルカンスルフォン酸１００ｇ／ｌ、添加剤３０ｃｃ／ｌからなる９０Ｓｎ／１０Ｐｂはんだめっき浴（４０℃）で電流密度３Ａ／ｄｍ²にてめっき厚さ１０μｍの９０Ｓｎ／１０Ｐｂはんだめっきを施した。その後、１５０℃オーブン中で１０００時間加熱し、２ｍｍＲで１８０°曲げた後平板に曲げ戻し、曲げ部においてはんだめっきの剥離の有無を目視で観察した。また、剥離を起こしていない試験片については、曲げ部の断面を研磨してめっき−母材の界面を光学顕微鏡で観察し、ミクロ的な剥離の有無まで確認した。
【００３８】
［Ａｇめっき性］
各試料より幅２５ｍｍ、長さ５０ｍｍの試験片を１０個ずつ採取し、各試験片に脱脂、酸洗後、シアン系Ａｇめっき浴を用いて厚さ１μｍの無光沢Ａｇめっきを行った。その後、Ａｇめっき表面の光沢の有無を目視調査し、光沢発生部が観察されなかった場合○、観察された場合×と評価し、その後さらに４００℃で１分間加熱して、ふくれの有無を調査し、膨れが観察されなかった場合○、観察された場合×と評価した。
また、その表面を観察し、突起の有無を調査した。５μｍ以上のものを突起として数え、１ｃｍ²あたり１個以下を合格○とした。
【００３９】
［Ｓｅ、Ｔｅ、Ｓｂ又はＢｉを含む化合物粒子］
各試料より１０ｍｍ×１０ｍｍの試験片を２個ずつ採取してその表面をＥＤＸで観察し（倍率：×１０００〜３０００）、表面に観察される粒子のＥＤＸスペクトルをとり、Ｓｅ、Ｔｅ、Ｓｂ又はＢｉのうちの１種以上が含まれる粒子で、かつその直径が０．１μｍを越えるものの個数を求めた。各試験片について１ｍｍ×１ｍｍの面積を２回ずつ、従って各試料については１ｍｍ×１ｍｍの面積を４回測定して、その平均値を測定結果として用い、直径０．１μｍを越えるものの個数が１０００個／ｍｍ²以下のものを○と評価し、１０００個／ｍｍ²を越えるものを×と評価した。なお、観察には、日本電子製ＪＳＭ５８００ＬＶ走査型電子顕微鏡（ＳＥＭ／ＥＤＸ）を用い、加速電圧は１５ｋＶである。
【００４０】
＜結果＞
各試料の調査結果を表５及び表６に示す。
【００４１】
【表５】

【００４２】
【表６】

【００４３】
明細書中に開示した適切な組成を有するＮｏ．１〜Ｎｏ．１４は、リードフレーム、端子コネクターなどの電機電子部品に要求される強度、導電率、ばね特性などに優れるだけでなく、めっき性、耐応力緩和特性などにおいても優れた特性を発揮することがわかる。
これに対して、Ｎｏ．１５は、Ｎｉの含有量が不足するため、強度が低く、Ａｇめっきした表面に突起が発生した。そして、Ｎｉ及びＳｉの含有量が過剰なＮｏ．１６は、熱延中に割れが発生し、それ以上冷延を継続することが実質的に不可能であった。
Ｚｎ含有量が本発明の下限値を下回るＮｏ．１７は、はんだめっきが５００時間で剥離し、Ｍｇ含有量が本発明の上限値を越えるＮｏ．１８は、冷延中激しい耳割れが発生して、それ以降の冷延が行えなかった。
Ｓｎ含有量が本発明の上限値を越えるＮｏ．１９は熱延温度及び加熱時間を変化させても、熱延時の割れを防止することが難しく、熱延方式による製造は困難なため、試験を行わなかった。
【００４４】
Ｄ群（Ｍｎ、Ｆｅ、Ｃｏ、Ａｇ、Ｃｒ、Ｚｒ、Ｔｉ）の元素の含有量が本発明の上限値を越えるＮｏ．２０はＮｏ．４と比べて伸びが十分でなく、曲げ加工を行うと割れが発生しやすい。また、導電率も低めである。
Ｃ群（Ｐ、Ａｌ）の元素の含有量が本発明の上限値を越えるＮｏ．２１は熱延割れが発生し、それ以後の工程を進めることが不可能であった。
Ａ群（Ｓｅ、Ｔｅ、Ｓｂ、Ｂｉ）の元素の含有量が本発明の上限値を越えるＮｏ．２２はこれらの元素を含む化合物が大量に発生し、無光沢Ａｇめっきを行っても光沢むら（前記化合物の覆い部分でめっきに光沢が出る)が発生し、リードフレーム、端子への適用が難しい。
水素の含有量が本発明の上限値を越えるＮｏ．２３は熱延時に耳割れが発生し、熱延性が低下し、またＡｇめっき後の加熱試験でふくれが発生し、Ａｇめっきを行う用途に適用することが難しい。
酸素の含有量が本発明の上限値を越えるＮｏ．２４は製造工程上は特に問題が生じなかったが、伸びが低いため曲げ加工性が悪い。また、Ａｇめっき後の加熱試験でふくれが発生し、Ａｇめっきを行う用途に適用することがやはり難しい。
【００４５】
（実施例２）
＜試料の製作＞
表７に示す５種類の組成の合金について、大気中で木炭被覆しながらコアレス炉により溶解し、半連続鋳造によって、厚さ１５０ｍｍ、幅６００ｍｍ、長さ５０００ｍｍの鋳塊を作製した。溶解鋳造においては溶解炉及び樋のカバーを十分に行い、溶湯の酸化及び水素ガス吸収を防止した。
【００４６】
【表７】

【００４７】
この鋳塊を９３０℃に１時間加熱後、厚さ１５ｍｍまで熱間圧延して、７００℃から水冷した。熱延材は、表面の酸化スケールをスカルパーで除去し、冷間圧延を行って０．３５７ｍｍｔのコイルを作製した。これらのコイルを８５０℃の連続焼鈍炉に通板して、溶体化処理を行った。組成ごとに予め求めておいた適正な速度で通板した。溶体化処理したコイルを酸洗後、厚さ減少率３０％の冷間圧延を行って板厚０．２５ｍｍとし、４４０〜５００℃で２時間の熱処理を行った。熱処理後の材料は表面の酸化膜を酸洗により除去し、試験に供した。
各試料のコイルについて、実施例１の要領で、引張り強さ、伸び、導電率及び結晶粒径を測定した後、以下の要領でスタンピング加工を行い、打抜き加工性を調査した。なお、コイルの全長及び幅方向において、成分、組織、機械的性質及び導電率を調査したところ、それらのばらつきはほとんどないことが確認された。
【００４８】
［打抜き加工性］
各試料の元コイルを、幅３０ｍｍにスリットして幅狭コイルとした。元コイルの幅方向の中央部付近からスリットした試料を用いて、幅０．５ｍｍ、長さ２０ｍｍのリードをプレス（ブルーダラー製）によって連続打抜き加工し、打抜かれたリード部のバリが０．０１ｍｍとなり、金型の再研磨が必要となるストローク数を測定した。ストローク数が３００万回を越えるものを○、３００万回に達しないものを×で評価した。なお、ブレス金型は超鋼製、そのクリアランスは片側０．０２５ｍｍ（リード幅の５％）、プレス打抜き条件は、打抜き速度約５００ショット／分である。
【００４９】
＜結果＞
各試料の調査結果を表８に示す。
【００５０】
【表８】

【００５１】
明細書中に開示した適切な組成を有するＮｏ．２５〜Ｎｏ．２８は、優れた打抜き加工性を有することがわかる。
これに対して、Ｎｏ．２９は、Ｍｇ及びＡ群（Ｓｅ、Ｔｅ、Ｓｂ、Ｂｉ）の元素の含有量が本発明の下限値を下回るため打抜き加工性が劣る。
【００５２】
（実施例３）
＜試料の製作＞
実施例２のＮｏ．２７合金について、０．３５７ｍｍの冷延材コイルを連続焼鈍する際その通板速度を変化させ、結晶粒径の異なるものを作製した。それらを０．２５ｍｍｔに冷延し、４４０〜５００℃に加熱して時効処理を行った。
【００５３】
＜試験方法＞
以下に示す方法でスタンピング時のバリ高さに及ぼす結晶粒径の影響及び曲げ加工時の肌荒れに及ぼす結晶粒径の影響を調査した。
［スタンピングバリ高さ］
実施例２において用いたプレスを用いて、リードを打抜き加工し、各結晶粒径の試料に対して１００００ショット打抜いた時点のリード部（リード長手方向は圧延方向に直角）のバリ高さを走査電子顕微鏡で観察した。観察数は１試料について２０個とし、その平均値を各試料のバリ高さとした。
［曲げ部外観］
ＣＥＳＭ０００２金属材料曲げ試験方法に規定されているＢ型曲げ治具で幅１０ｍｍ、長さ３５ｍｍの試験片をはさみ、島津製作所製万能試験機ＲＨ−３０を使い、１Ｔｏｎの荷重で曲げ半径０．２５ｍｍの曲げ加工を行った。なお、曲げ線は圧延方向に直角となるように、各試料について５個ずつの試料を用いて試験を行った。その後、曲げ部の外側をオリンパス光学製ＳＺＨ型光学式実体顕微鏡を用い、倍率４０倍で観察して、結晶粒径の数倍程度で現れる肌荒れ発生の有無を調査した。
【００５４】
＜試験結果＞
結果を表９に示す。
【００５５】
【表９】

【００５６】
結晶粒径が２０μｍ以下であるＮｏ．２７−１〜Ｎｏ．２７−４においては、スタンピングバリの発生量が小さく、曲げ試験後の肌荒れの発生もなく、良好なスタンピング性及び曲げ加工性を有する。一方、結晶粒径が２０μｍを越えるＮｏ．２７−５及びＮｏ．２７−６においては、スタンピングバリの発生量が急に大きくなり、曲げ試験後の肌荒れが発生するようになる。
【００５７】
（実施例４）
＜試料の製作＞
実施例２において用いたＮｏ．２７試料を用いた。コイル外周より１００ｍの位置より２５ｍｍ×５０ｍｍの試験片を切り出し、粗さの異なるば布で研磨することによって表面粗さを変化させた。粗さ調整を行った試料はアセトンに浸漬して超音波洗浄後、さらに電解脱脂を行い、加熱試料とした。各試料について試験片の個数は５個ずつとした。
なお、加熱前に試験片表面をＸ線光電子分析装置（ＶＧ製ＥＳＣＡＬＡＢ−２１０Ｄ）て測定し（Ｍｇ、Ｋα、１５ｋＶ、２０ｍＡ）、初期酸化状態を調査した。酸素ピーク強度と銅ピーク強度の比（Ｏ１ｓ）／（Ｃｕ２ｐ）は各試験片とも０．４で、初期酸化状態は一定であった。
【００５８】
＜試験方法＞
以下に示す方法で酸化膜密着性に及ぼす表面粗さの影響を調査した。
［表面粗さ］
アセトンで超音波洗浄した各試験片について圧延方向に平行に、長さ５ｍｍにわたりプローブを走査して粗さを測定した。各試料の５個の試験片はほぼ同一の表面粗さを示した。各試料の表面粗さとしては５個のデータの平均値を用いた。表面粗さの測定は触針式表面粗さ測定器（Ｔａｙｌｏｒ Ｈｏｂｓｏｎ製）を用いた。なお、表面粗さの定義はＪＩＳ−Ｂ０６０１（表面粗さの定義と表示）による。
【００５９】
［酸化膜の密着性］
３００℃に保持したホットプレート（ＳＥＦＩ社製ホットプレートＨＨＰ−４０１）の上に各表面粗さの試験片を置いて３０分間加熱した。所定時間経過後、室温に冷却し、市販のアセテート粘着テープ（スリーエムＮｏ．８１０）を張付け、直ちに引き剥がしてテープ粘着面への酸化膜の付着の有無を目視で調査した。粘着面への酸化膜の付着がないものを○、粘着面に少しでも酸化膜が付着しているものを×と評価した。なお、ホットプレートによる加熱及び引き剥がし試験は、２５℃、相対湿度６０％の室内で実施した。
【００６０】
＜試験結果＞
結果を表１０に示す。
【００６１】
【表１０】

【００６２】
表面粗さがＲａ：０．２μｍ以下、Ｒｍａｘ：１．０μｍ以下であるＮｏ．２７−７及びＮｏ．２７−８においては、酸化膜が剥離しないが、表面粗さが上記範囲を越えるＮｏ．２７−９及びＮｏ．２７−１０においては、酸化膜が剥離する。
【００６３】
【発明の効果】
本発明に係る銅合金は、電気・電子部品として要求される強度、導電率、はんだの耐熱剥離性などの特性を満足するとともに、スタンピング加工性（スタンピング金型の磨耗が小さく、発生するバリ、だれが小さい）、めっき性にも優れる。従って、本発明は電気・電子部品の生産性及び信頼性向上に大きく寄与する。
【図面の簡単な説明】
【図１】 応力緩和特性を評価する方法を説明するための斜視図である。
【図２】 その側面図である。
【符号の説明】
１ 試験片[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-strength copper alloy excellent in stamping workability, plating property, and stress relaxation rate used for electrical / electronic parts such as semiconductor lead frames, terminals, connectors, relays, and switches.
[0002]
[Prior art]
In recent years, along with the miniaturization, weight reduction, and high integration of electrical / electronic components, the lead frame lead spacing or connector inter-electrode pitch and the wall thickness have been reduced to reduce the mounting volume. It has been. For this reason, demands for migration resistance and whisker resistance (suppression of whisker of Sn plating) are becoming stricter for these materials as well as demands for higher strength and higher electrical conductivity than before. In order to meet such strict requirements, as Cu—Ni—Si based copper alloy, for example, Ni: 0.4 to 4.0 wt%, as defined in JP-A-8-319527, Si: 0.1 to 1.0 wt%, Zn: 1.0 to 2.0 wt%, Cr: 0.0001 to 0.01 wt%, Mg: 0.0001 to 0.001 wt%, and optionally Mn : Copper alloy containing 0.01-0.1 wt% and Al: 0.0001-0.01 wt% is proposed.
[0003]
Lead frames and terminals are usually manufactured from a copper alloy material by stamping. In stamping, as the number of times of punching increases, the mold wears, and burrs and drippings occur in the punched product. If they exceed the allowable limit, the dimensional accuracy of the product, residual stress, etc. exceed the standard values, so it is necessary to stop the operation and polish the mold. In this way, from the viewpoint of productivity and yield, the copper alloy used for the lead frame and the terminal, in addition to the above-mentioned characteristics, does not wear the mold, and burrs generated when stamping is performed. There has been a strong demand for as little as possible. Even in the above copper alloy, it cannot be said that stamping is sufficient, and further improvement is demanded.
[0004]
[Problems to be solved by the invention]
In the present invention, stamping workability (wearing of stamping molds and burrs in stamped copper alloys is maintained while maintaining the strength, conductivity, stress relaxation resistance, plating properties, etc. of the Cu-Ni-Si alloy described above. The reduction of who) was made to further improve.
[0005]
[Means for Solving the Problems]
The copper alloy for electric / electronic parts according to the present invention is Ni: 0.1 1.81 wt%, Si: 0.01 to 1.0 wt%, Zn: 0.01 to 5.0 wt%, S: 0.005 wt% or less, Se: 0.003 wt% or less, Te: 0.003 wt% Hereinafter, 0.005 wt% or less of one or more elements selected from the group of Sb: 0.003 wt% or less and Bi: 0.003 wt% or less is contained, and the balance consists of Cu and inevitable impurities. S is within a range of 0.0001 to 0.005 wt%, and Se, Te, Sb, and Bi (the above is referred to as an A group element) is Se: 0.00003 to 0.003 wt%, Te: 0.0. Within a range of 00003 to 0.003 wt%, Sb: 0.00003 to 0.003 wt%, and Bi: 0.00003 to 0.003 wt%, one or more of these in a total of 0.00003 to 0.003. It is preferable to contain 005 wt%.
[0006]
The copper alloy for electrical and electronic parts is further one of elements selected from the group (referred to as element B) of (1) Pb: 0.0001 to 0.05 wt%, C: 0.0001 to 0.01 wt% Or, two kinds were selected from the group of 0.0001 to 0.05 wt% in total, (2) P: 0.0001 to 0.1 wt%, Al: 0.0005 to 0.3 wt% (referred to as group C element) 1 type or 2 types in total 0.0001 to 0.3 wt%, (3) Mg: 0.001 to 1.5 wt%, (4) Mn: 0.001 to 0.5 wt%, Fe: 0.001 -0.03 wt%, Co: 0.001-0.1 wt%, Ag: 0.0003-0.1 wt%, Cr: 0.0005-0.01 wt%, Zr: 0.0005-0.01 wt% , Ti: selected from 0.0005 to 0.01 wt% group (referred to as group D element) The 0.0003~0.7wt% 1 or two or more in total and can contain a combination B to D, respectively Mg alone or their appropriately.
[0007]
The copper alloy for electric / electronic parts is desirably regulated to have an oxygen content of 30 ppm or less and a hydrogen content of 10 ppm or less.
Moreover, the said copper alloy for electrical / electronic components can contain Sn: 0.01-8.0wt% further.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The reasons for limiting the components of the copper alloy according to the present invention will be described below.
(Ni)
Ni, when added together with Si, produces an Ni—Si compound and has the effect of improving strength, heat resistance and stress relaxation resistance. If it is less than 0.1 wt%, this effect is small, and if it exceeds 4.0 wt%, the hot workability and the cold workability deteriorate, which is not preferable. Accordingly, the Ni content is 0.1 to 4.0 wt%. Is desirable .
(Si)
When Si is added together with Ni, it has the effect of generating a Ni-Si compound and improving strength, heat resistance and stress relaxation resistance. If it is less than 0.01 wt%, this effect is small, and if it exceeds 1.0 wt%, the hot workability and the cold workability deteriorate, which is not preferable. Accordingly, the Si content is set to 0.01 to 1.0 wt%.
[0009]
(Zn)
Improvement of migration resistance, suppression of whisker generation of Sn and Sn alloy plating, improvement of heat release resistance of Sn and Sn alloy plating, improvement of migration resistance, reduction of wear of stamping mold, improvement of adhesion of oxide film, molten metal Deoxidation effect, molten hydrogen dehydrogenation, etc. If it is less than 0.01 wt%, the effect is not obtained, and if it exceeds 5.0 wt%, the electrical conductivity is lowered and the solder wettability is deteriorated. Therefore, the content is set to 0.01 to 5.0 wt%.
[0010]
(S)
When added to the copper alloy, it has the effect of reducing the wear of the press die, and improves stamping workability such as reducing burrs and dripping of the stamping material. If the S content is less than 0.0001 wt%, the effect is not sufficient. The effect increases as the S content increases, but if the content exceeds 0.005 wt%, the Ag plating property deteriorates. That is, the amount of Mg—S compound formed in the alloy increases, and when Ag plating is performed, Ag tends to be abnormally precipitated in a protruding shape starting from the Mg—S compound present on the alloy surface ( Hereinafter referred to as Ag protrusion). This Ag protrusion becomes a problem because when this alloy is used as a lead frame for performing Ag plating, the reliability of bonding wire bonding and plating adhesion is lowered. Therefore, the S content is set to 0.0001 to 0.005 wt%.
[0011]
(Group A elements: Se, Te, Sb, Bi)
When these elements are added to a copper alloy even in a very small amount, they have the effect of reducing the wear of the press die by lubrication and improve the stamping workability, such as reducing burrs and drooling of the stamping material. . Therefore, the life of the press die (the number of punches before re-polishing) is improved, the dimensional accuracy and flatness of the stamped lead frame and electrical / electronic parts such as terminals are improved, and the lead spacing is further reduced. Enable.
[0012]
The above-mentioned effect increases as the total content of Se, Te, Sb, and Bi increases, but any content exceeds 0.003 wt%, or the total content exceeds 0.005 wt%. In this case, if the alloy is subjected to Ag plating (matte, semi-glossy, glossy), a compound of these elements or these elements and S, Cu, Al, Ag, Co, Cr, Fe, Ni , Sn, Pb, Zn, O, etc. alone or in the presence of complex compounds, abnormal precipitation of Ag plating occurs and is observed as gloss abnormalities or uneven gloss. Furthermore, ingot cracking is likely to occur during casting, heating of the ingot, or hot rolling. Therefore, the content of these elements is one element selected from the group of Se: 0.003 wt% or less, Te: 0.003 wt% or less, Sb: 0.003 wt% or less, Bi: 0.003 wt% or less. Or 2 or more types must be 0.005 wt% or less.
Although these elements have the above-described effects even in a very small amount, Se: 0.00003 to 0.003 wt%, Te: 0.00003 to 0.003 wt%, Sb: 0.00003 to 0.003 wt%, Bi: 0 The total content of one or more selected from the group of 0.00003 to 0.003 wt% is preferably 0.00003 to 0.005 wt%.
[0013]
In addition, when the relationship between the above-mentioned compound particles existing on the surface of the alloy plate and the conditions for occurrence of abnormal gloss of Ag plating was examined, 1000 / mm of the above-mentioned particles were 0.1 μm or more. ² It has been found that an abnormal luster of Ag plating tends to occur when the thickness exceeds. Therefore, the number of compound particles existing on the plate surface is 1000 / mm. ² It is necessary that:
[0014]
(Group B elements: Pb, C)
All of these elements have the effect of improving the stamping workability of the present alloy (burrs of the stamping material, less dripping, and reduction of wear of the stamping mold). When both Pb and C are less than 0.0001 wt%, the above effects are not sufficient. Further, when Pb exceeds 0.05 wt% or C exceeds 0.01 wt%, or when the total content thereof exceeds 0.05 wt%, ingot cracking is likely to occur during casting or ingot heating. In addition, hot workability is reduced. Accordingly, one or two elements selected from the group of Pb: 0.0001 to 0.05 wt% and C: 0.0001 to 0.01 wt% are made 0.0001 to 0.05 wt% in total.
[0015]
(Group C elements: P, Al)
Any of these elements exerts a deoxidation effect when added to the molten alloy, prevents oxidation of Mg during melt casting, and improves the internal quality and surface quality of the ingot. When P is less than 0.0001 wt% and Al is less than 0.0005 wt%, the above-described effects are not sufficient. Also, if any of these elements exceeds P: 0.1 wt%, Al: exceeds 0.3 wt%, or if the total of one or two of these elements exceeds 0.3 wt%, the conductivity decreases. , Sn and Sn alloy plating heat resistance peelability decreases. Accordingly, one or two selected from the group of P: 0.0001 to 0.1 wt% and Al: 0.0005 to 0.3 wt% are set to 0.0001 to 0.3 wt% in total.
[0016]
(Mg)
When added to a copper alloy, the strength can be improved without significantly reducing the electrical conductivity. Furthermore, improved migration resistance, improved spring limit value, improved response force relaxation rate, improved stamping processability (stamping material burrs, less dripping, reduced stamping mold wear), molten metal deoxidation effect Etc. Moreover, S in molten metal is fixed as a Mg-S compound, and hot workability is improved. If the amount is less than 0.001 wt%, the effect is not obtained. If the amount exceeds 1.5 wt%, the soundness of the ingot is lowered due to an increase in the viscosity of the molten metal, and intergranular cracking during hot rolling tends to occur. Moreover, since work hardening becomes large and problems, such as an ear crack at the time of cold rolling and deterioration of bending workability, generate | occur | produce, the content is restrict | limited to 0.001-1.5 wt%.
Mg forms a compound with S and affects not only stamping workability but also silver plating properties. From the standpoint of stamping workability, it is desirable that the amount of Mg and S is large, but the Mg-S compound present in the copper alloy increases, and the portion of the Mg-S compound present on the plate surface when silver plating is performed. Ag local precipitation occurs and Ag protrusions are formed. In order to prevent this phenomenon, the amount of Mg dissolved in the copper alloy matrix should be increased. The Mg content (wt%) of the alloy is [Mg] and the S content (wt%) is [S]. Sometimes, it is desirable to make it contain in the ratio which satisfies the following formula.
0.25 [Mg] ≧ [S]
[0017]
(Group D elements: Mn, Fe, Co, Ag, Cr, Zr, Ti)
All of these elements improve the strength, response capability relaxation characteristics, and heat resistance of the alloy. Any of these elements is Mn: less than 0.001 wt%, Fe: less than 0.001 wt%, Co: less than 0.001 wt%, Ag: less than 0.0003 wt%, Cr: less than 0.0005 wt%, Zr: 0.00. If less than 0005 wt%, Ti: less than 0.0005 wt%, or the total of one or more of these is less than 0.0003 wt%, the effect is not sufficient. Any of these elements is Mn: more than 0.5 wt%, Fe: more than 0.03 wt%, Co: more than 0.1 wt%, Ag: more than 0.1 wt%, Cr: more than 0.01 wt%, If Zr exceeds 0.01 wt%, Ti exceeds 0.01 wt%, or if the total of one or more of these exceeds 0.7 wt%, the ductility and electrical conductivity of the material will decrease. Therefore, Mn: 0.001 to 0.5 wt%, Fe: less than 0.001 to 0.03 wt%, Co: 0.001 to 0.1 wt%, Ag: 0.0003 to 0.1 wt%, Cr: One or two or more selected from the group of 0.0005 to 0.01 wt%, Zr: 0.0005 to 0.01 wt%, Ti: 0.0005 to 0.01 wt% in total are 0.0003 to 0.005. 7 wt%.
In addition, this alloy contains Si as an essential element, and when P is added from the group C element, silicide or / and phosphide of the group D element is formed depending on the processing heat treatment conditions, and the strength, heat resistance, response capability This further contributes to the improvement of relaxation characteristics and conductivity.
[0018]
(oxygen)
If the oxygen content of the copper alloy exceeds 30 ppm, it causes a decrease in solderability, a decrease in plating properties, and the like, and also reduces the heat-resistant peelability of solder and plating. In addition, since oxides increase in the alloy, phenomena such as cracking of the cold-rolled material and a decrease in bending workability occur due to a decrease in ductility during cold working, thereby reducing press punchability. Therefore, the content is set to 30 ppm or less. In this alloy, the desirable range of oxygen content is 20 ppm or less, and the more desirable range is 15 ppm or less.
The oxygen content in this alloy is the total amount of oxygen and copper or / and oxides of additive elements that are dissolved in the alloy.
[0019]
(hydrogen)
If the hydrogen content of the alloy exceeds 10 ppm, hot workability degradation, Ag plating, Ni plating, etc., will tend to cause blistering due to heating, and it can be used as the intended electrical / electronic component. It becomes difficult. Therefore, the content is made 10 ppm or less. In this alloy, the desirable range of the hydrogen content is 5 ppm or less, and the more desirable range is 3 ppm or less.
The content of oxygen and hydrogen in the alloy is [H] in the product sheet by sufficiently drying the raw materials and controlling the atmosphere in the melt casting process. ² [O] can be kept in the range of 3 to 100 ([H]: amount of hydrogen contained in the alloy (ppm), [O]: amount of oxygen contained in the alloy (ppm)).
[0020]
(Sn)
The strength and spring limit value of the present alloy containing Mg are further improved by forming a solid solution with the Cu matrix or forming a compound with Mg. If it is less than 0.01 wt%, the effect is small, and if it exceeds 8.0 wt%, hot working becomes difficult and the decrease in conductivity also increases. Therefore, the Sn content is 0.01 to 8.0 wt%.
[0021]
The copper alloy according to the present invention can be manufactured by a process in which an ingot formed by continuous casting is hot-rolled and then combined with cold rolling and heat treatment to obtain a predetermined thickness. Besides this, hot rolling is not adopted, and an ingot having a thickness of 5 to 30 mm formed by horizontal continuous casting can be heat-treated and cold-rolled to have a predetermined thickness.
[0022]
The copper alloy according to the present invention has good hot rollability and cold rollability, and does not cause problems such as cracking in each process. Even in the case of carrying out, the machinability is very excellent, so that the scalper blade is hardly worn and the surface is hardly seized. In addition, since the copper alloy of the present invention is strengthened by precipitating a Ni—Si compound in the matrix, solution treatment and aging treatment are required. The solution treatment can be performed by rapid cooling of the hot-rolled material immediately after completion of hot rolling by water cooling, and / or a method of rapid cooling after passing through a continuous heating furnace at a predetermined temperature of the cold-rolled material. As the precipitation treatment, it is desirable to use a batch-type heating furnace in order to sufficiently precipitate Ni and Si dissolved by the solution treatment, but when the addition amount of Ni and Si is small or the precipitation amount is small. If there is no problem, a continuous heat treatment furnace may be used. The conditions for solution treatment and aging treatment are determined in consideration of Ni and Si contents, target mechanical properties, electrical conductivity, crystal grain size, etc. When a continuous heat treatment furnace is used from a temperature of 600 ° C. or higher, the ambient temperature is desirably 650 ° C. or higher. The aging treatment conditions of the copper alloy of the present invention may be a heating temperature of 400 to 600 ° C. and a holding time of 5 to 600 minutes.
[0023]
Further, the alloy of the present invention may be subjected to aging treatment or subsequent cold rolling to obtain cold rolling, or the cold rolled material may be further subjected to heat treatment for the purpose of recovering ductility, improving distortion, improving the spring limit value, etc. . The processing rate in the case of cold rolling is 3-80% in terms of the reduction rate of the plate thickness.
When the heat treatment is performed after the final cold rolling, either a batch method or a continuous method may be used. When using a batch-type heating furnace, hold at 200 to 500 ° C. × 5 minutes to 5 hours (material arrival temperature × holding time after reaching), and when using a continuous annealing furnace, hold at 300 to 800 ° C. × 10 to 300 seconds ( The object can be achieved under the condition of material temperature x holding time after arrival. After cold rolling, a process such as tension leveling and tension annealing may be applied, or after cold rolling and annealing, a process such as tension leveling and tension annealing may be applied to correct the distortion.
[0024]
As described above, in the case of using any tempering after cold rolling or heat treatment, the crystal grain size in the plate thickness direction in the thin plate cross section parallel to the rolling direction may be 20 μm or less. In addition, in the cross section parallel to the rolling direction as the rolling processing rate increases, the crystal grains become flat in the plate thickness direction and finally become a fibrous structure. In the present invention, the crystal grains in this plate thickness direction The particle diameter should just be 20 micrometers or less.
When the crystal grain size exceeds 20 μm, the occurrence of flash during stamping increases. In addition, rough skin called orange peel and cracks resulting therefrom are likely to occur in the bent portion during bending after stamping. Furthermore, the strength is also reduced. Therefore, the crystal grain size of the alloy is desirably 20 μm or less. From the viewpoints of flash during stamping, rough skin during bending, cracks in the bent portion, and strength, the crystal grain size is more preferably 15 μm or less, and further preferably 10 μm or less. If the crystal grain size is in the above range, the copper alloy of the present invention has good etching processability and can be used as a lead frame material for etching process.
[0025]
The lead frame, which is an application of this alloy, is heated to 200 to 350 ° C. in the Si chip mounting and packaging process. In the wire bonding process, heating is usually performed in a non-oxidizing atmosphere such as a nitrogen-hydrogen mixed gas in order to prevent oxidation during heating, but it is difficult to completely prevent air from entering the heating furnace. For this reason, when a line stop occurs due to an unforeseen situation, the time spent in the furnace becomes longer, and therefore, it is oxidized by the invading atmosphere. If the adhesion strength between the oxide film formed on the surface of the lead frame and the base material is low, moisture will intrude through the gap formed when the oxide film is peeled off from the base material after resin molding, and the reliability of the IC will be significantly reduced. . For this reason, when used in a lead frame, the adhesion of the oxide film is an important required characteristic.
When the surface roughness of this alloy exceeds the center line average roughness (Ra) of 0.2 μm or the maximum height (Rmax) exceeds 1.0 μm, the adhesion of the oxide film is lowered. In this respect, the surface roughness is desirably Ra: 0.2 μm or less and Rmax: 1.0 μm or less. When the surface roughness satisfies this condition, there is no problem in plating properties, bending workability, etc., and it is suitable for electric / electronic parts such as lead frames, terminals and connectors.
[0026]
Furthermore, in the alloy of the present invention, in addition to the elements described above, B, Ca, Sc, V, Ge, As, Sr, Y, Nb, Mo, Rh, Pd, Cd, In, rare earth elements, Hf, Ta, If one or more elements selected from W, Re, Os, Pt, Au, etc. are 0.0001 wt% to 0.1 wt% for each element, and the total is 0.0001 to 0.3 wt%, the conductivity, stamping process In order to improve the heat resistance, the response relaxation characteristics and the corrosion resistance without greatly degrading the properties, plating properties and the like, it may be contained.
[0027]
【Example】
Examples of the copper alloy for electric / electronic parts according to the present invention will be described below.
Example 1
<Preparation of sample>
No. 1 shown in Tables 1 to 4 while being covered with charcoal in the atmosphere. An alloy having a composition of 1 to 24 was melted in a kryptor furnace and cast into a book mold to produce an ingot having a thickness of 50 mm, a width of 90 mm, and a length of 200 mm. In addition, in order to prevent hydrogen from entering the molten metal, measures such as drying of raw materials, fluxes, molds, jigs, and red heat of charcoal were taken (except for No. 23).
[0028]
[Table 1]

[0029]
[Table 2]

[0030]
[Table 3]

[0031]
[Table 4]

[0032]
The ingot was heated to 930 ° C. for 1 hour, and then hot-rolled to a thickness of 15 mm, hot rolling was finished at 750 ° C. or higher, and water-cooled. In addition, No. with Mg content exceeding 1.5%. No. 18 alloy, No. with Sn content exceeding 8% No. 19 alloy and no. Since alloy No. 21 may be hot-rolled, it was heated at 700 ° C. for 1 hour for homogenization, then heated to 750-850 ° C. and hot-rolled.
No. 16, no. 19 and No. Since No. 21 alloy cracked during hot rolling and subsequent cold rolling was considered impossible with a thickness of 15 mm, the subsequent steps were not applied. No. In the alloy No. 23, light ear cracking occurred at the end surface portion in the hot rolling, but the ear cracking portion was removed and the subsequent process was applied.
[0033]
The hot-rolled material was mechanically removed from the surface oxide scale and cold-rolled to 0.357 mmt. However, no. In No. 18, the ear cracks became severe during cold rolling, so rolling was stopped and the subsequent steps were not applied. Thereafter, the solution was heated to 650 to 850 ° C. for 20 seconds for solution treatment, and then rapidly cooled in water.
Further, after the surface oxide film was pickled and removed, cold rolling was performed at a thickness reduction rate of 30% to obtain a plate thickness of 0.25 mm, and heat treatment was performed at 440 to 500 ° C. for 2 hours. The material after the heat treatment was subjected to a test after removing the oxide film on the surface by pickling.
Hereinafter, an analysis method of alloy elements and a test method of alloy characteristics performed in this example will be described.
[0034]
<Analysis of alloy element content and gas content>
[Alloy elements]
A sample is taken from a thin plate, fully degreased, and a method defined in JIS (Zn, Mn, Ni, Fe, Co, Cr, P, Si, Al, Se, Te, Pb, As), ICP -MS, GD-MS, atomic absorption method and the like were used for analysis. In addition, it analyzed twice about each element and made the average value the content.
[gas]
A sample was taken from the thin plate and electropolished in hydrochloric acid to remove the oxide film on the surface sufficiently, and then analyzed.
Among these, oxygen was measured by the method (inert gas melting infrared absorption method) prescribed | regulated to JIS-H1067. In this method, since the oxide is heated to a temperature at which it melts, the amount of oxygen to be measured is determined by forming an oxide with oxygen dissolved in the copper alloy and copper and / or other elements. The sum of oxygen. Each sample was measured three times, and an average value thereof was used as a measured value.
Hydrogen was measured by the method prescribed in JIS-Z2614. Each sample was measured three times, and an average value thereof was used as a measured value.
[0035]
<Test method>
[mechanical nature]
A JIS No. 5 test piece in which the longitudinal direction of the test piece was parallel to the rolling direction was processed, and tensile strength and elongation were measured. The number of test pieces was three for each sample, and the average value of the measured values was taken as the measurement result.
[conductivity]
Based on the method defined in JISH0505, a double bridge 5752 manufactured by Yokogawa Electric was used for the measurement. Two test pieces were used for each sample, and the average value of the measured values was taken as the measurement result.
[Spring limit value]
Based on JISH3130, the amount of permanent deflection at room temperature was measured by a moment formula test, and Kb0.1 was calculated. The longitudinal direction of the test piece was parallel to the rolling direction. Ten test pieces were used for each sample, and the average value of the measured values was taken as the measurement result.
[Stress relaxation characteristics]
[0036]
As shown in FIGS. 1 and 2, a test piece 1 having a width of 10 mm is cantilevered, and a bending stress of 80% of the test piece's proof stress is applied to the position of length (l) 80 mm to add the stress. In this state, the stress was removed after holding at 160 ° C. for 1000 hours. The deflection amount (δ: 10 mm) of the test piece at the load point when stress was applied and the displacement amount (ε1) when the stress was removed were measured, and the stress relaxation rate was measured by the following equation. Ten test pieces were collected from each sample, and the average value of the measured values was used as the measurement result.
Stress relaxation rate (%) = (ε1 / δ) × 100
The bending stress (σ) is calculated by the following formula.
σ = (3 × E × t × δ) / (2 × l ² )
However,
σ: bending stress = proof strength of test piece × 0.8
E: Young's modulus of test piece (N / mm ² )
t: Thickness of the test piece = 0.25 mm
[0037]
[Crystal grain size]
The crystal grain size is measured by a cutting method prescribed in JIS-H0501 for the crystal grain size in the plate thickness direction in a plate cross section parallel to the rolling direction. Five test pieces were sampled from each sample, and optical micrographs were taken for each of the three test fields (magnification: 100 to 200 times). The photographed photograph was measured by a cutting method, and the average value of 15 data was defined as the crystal grain size.
[Heat-resistant peelability of Sn and Sn alloy plating]
In the alloy of the present invention, similar results are obtained regardless of whether Sn plating or Sn alloy plating is performed. Therefore, in this example, solder plating was performed to investigate the heat-resistant peelability. Ten test pieces each having a width of 10 mm and a length of 50 mm were taken from each sample.
As solder plating, 193 g / l stannous alkanol sulfonate, 3.5 g / l lead alkanol sulfonate, 100 g / l alkane sulfonic acid, and a 30 Sn / 10 Pb solder plating bath (40 ° C.) composed of 30 cc / l additive. Current density 3A / dm ² The 90 Sn / 10 Pb solder plating with a plating thickness of 10 μm was applied. Then, it was heated in a 150 ° C. oven for 1000 hours, bent at 180 ° at 2 mmR, bent back to a flat plate, and visually observed for peeling of the solder plating at the bent portion. Moreover, about the test piece which has not raise | generated peeling, the cross section of the bending part was grind | polished, the interface of plating-base material was observed with the optical microscope, and the presence or absence of micro peeling was confirmed.
[0038]
[Ag plating property]
Ten test pieces each having a width of 25 mm and a length of 50 mm were collected from each sample, and each test piece was degreased and pickled, and then subjected to matte Ag plating with a thickness of 1 μm using a cyan-based Ag plating bath. Thereafter, the presence or absence of gloss on the surface of the Ag plating is visually inspected. If no gloss generation portion is observed, it is evaluated as ○. If it is observed, it is evaluated as ×, and further heated at 400 ° C. for 1 minute to investigate the presence or absence of blistering. In the case where no swelling was observed, the evaluation was ○, and in the case where it was observed, the evaluation was ×.
In addition, the surface was observed to investigate the presence of protrusions. Count 5μm or more as protrusions, 1cm ² One or less per pass was considered as pass ○.
[0039]
[Compound particles containing Se, Te, Sb or Bi]
Two 10 mm × 10 mm test specimens are collected from each sample, and the surface is observed with EDX (magnification: × 1000 to 3000). EDX spectra of particles observed on the surface are taken, and Se, Te, Sb or The number of particles containing one or more of Bi and having a diameter exceeding 0.1 μm was determined. The area of 1 mm × 1 mm is measured twice for each test piece, and therefore the area of 1 mm × 1 mm is measured four times for each sample, and the average value is used as a measurement result. Piece / mm ² The following items are evaluated as ○ and 1000 pieces / mm ² A product exceeding 1 was evaluated as x. For observation, a JSM5800LV scanning electron microscope (SEM / EDX) manufactured by JEOL Ltd. was used, and the acceleration voltage was 15 kV.
[0040]
<Result>
The survey results of each sample are shown in Tables 5 and 6.
[0041]
[Table 5]

[0042]
[Table 6]

[0043]
Appropriately disclosed in the specification No. having the composition. 1-No. No. 14 not only excels in strength, electrical conductivity, spring characteristics, etc. required for electrical and electronic parts such as lead frames and terminal connectors, but also exhibits excellent characteristics in terms of plating properties and stress relaxation resistance. .
In contrast, no. 15 is Ni content is insufficient Therefore, the strength was low, and protrusions were generated on the Ag-plated surface. And the content of Ni and Si is Excessive No. In No. 16, cracks occurred during hot rolling, and it was virtually impossible to continue cold rolling.
No. Zn content falls below the lower limit of the present invention. No. 17 is a No. 17 in which the solder plating peels off in 500 hours and the Mg content exceeds the upper limit of the present invention. No. 18 was severely cracked during cold rolling and could not be cold rolled thereafter.
No. Sn content exceeding the upper limit of the present invention. No. 19 was not tested because it was difficult to prevent cracking during hot rolling even when the hot rolling temperature and heating time were changed, and it was difficult to manufacture by the hot rolling method.
[0044]
No. D group element content (Mn, Fe, Co, Ag, Cr, Zr, Ti) exceeds the upper limit of the present invention. No. 20 is No. Elongation is not sufficient compared to 4, and cracking tends to occur when bending is performed. Also, the conductivity is low.
No. C group (P, Al) element content exceeds the upper limit of the present invention. No. 21 was hot-rolled and it was impossible to proceed with the subsequent steps.
No. in which the content of the elements of Group A (Se, Te, Sb, Bi) exceeds the upper limit of the present invention. In No. 22, a compound containing these elements is generated in large quantities, and even when matte Ag plating is performed, gloss unevenness occurs (the plating covers the surface of the compound is glossy), which makes it difficult to apply to lead frames and terminals. .
No. in which the hydrogen content exceeds the upper limit of the present invention. No. 23 is cracked at the time of hot rolling, the hot ductility is lowered, and blisters are generated in a heating test after Ag plating, and it is difficult to apply to the use for performing Ag plating.
No. in which the oxygen content exceeds the upper limit of the present invention. No particular problem occurred in the manufacturing process 24, but the bending workability was poor because the elongation was low. In addition, blistering occurs in the heating test after Ag plating, and it is still difficult to apply to applications where Ag plating is performed.
[0045]
(Example 2)
<Production of sample>
Shown in Table 7 5 types The alloy having the composition was melted in a coreless furnace while being coated with charcoal in the atmosphere, and an ingot having a thickness of 150 mm, a width of 600 mm, and a length of 5000 mm was produced by semi-continuous casting. In melting and casting, the melting furnace and dredging cover were sufficiently covered to prevent the molten metal from being oxidized and absorbing hydrogen gas.
[0046]
[Table 7]

[0047]
The ingot was heated to 930 ° C. for 1 hour, hot-rolled to a thickness of 15 mm, and water-cooled from 700 ° C. The hot-rolled material was obtained by removing the oxide scale on the surface with a scalper and performing cold rolling to produce a 0.357 mmt coil. These coils were passed through a continuous annealing furnace at 850 ° C. for solution treatment. The sheet was passed at an appropriate speed determined in advance for each composition. After the solution-treated coil was pickled, it was cold-rolled at a thickness reduction rate of 30% to a plate thickness of 0.25 mm and heat-treated at 440 to 500 ° C. for 2 hours. The material after the heat treatment was subjected to a test after removing the oxide film on the surface by pickling.
About the coil of each sample, after measuring the tensile strength, elongation, electrical conductivity, and crystal grain size in the same manner as in Example 1, stamping was performed in the following manner to investigate the punching workability. In addition, when the composition, the structure, the mechanical properties, and the conductivity were examined in the entire length and width direction of the coil, it was confirmed that there was almost no variation.
[0048]
[Punching workability]
The original coil of each sample was slit to a width of 30 mm to form a narrow coil. Using a sample slit from the central portion in the width direction of the original coil, a lead having a width of 0.5 mm and a length of 20 mm was continuously punched by a press (manufactured by BRUDERER). The number of strokes which was 01 mm and required to re-grind the mold was measured. A case where the number of strokes exceeded 3 million times was evaluated as ◯, and a case where the number of strokes did not reach 3 million times was evaluated as ×. The brace mold is made of super steel, the clearance is 0.025 mm on one side (5% of the lead width), and the press punching condition is a punching speed of about 500 shots / minute.
[0049]
<Result>
The survey results for each sample are shown in Table 8.
[0050]
[Table 8]

[0051]
Appropriately disclosed in the specification No. having the composition. 25-No. It can be seen that No. 28 has excellent punching workability.
In contrast, no. No. 29 is inferior in punching workability because the content of elements of Mg and Group A (Se, Te, Sb, Bi) is below the lower limit of the present invention.
[0052]
(Example 3)
<Production of sample>
No. 2 in Example 2. About 27 alloy, when the 0.357 mm cold-rolled material coil was continuously annealed, the plate passing speed was changed, and those with different crystal grain sizes were produced. They were cold-rolled to 0.25 mm and heated to 440 to 500 ° C. for aging treatment.
[0053]
<Test method>
The influence of the crystal grain size on the burr height during stamping and the effect of the crystal grain size on rough skin during bending were investigated by the following methods.
[Stamping burr height]
Using the press used in Example 2, the lead was punched and the burr height of the lead portion (lead longitudinal direction is perpendicular to the rolling direction) at the time of punching 10,000 shots for each crystal grain size sample was determined. Observed with a scanning electron microscope. The number of observations was 20 per sample, and the average value was the burr height of each sample.
[Bent part appearance]
Using a B-type bending jig specified in the CESM0002 metal material bending test method, a test piece having a width of 10 mm and a length of 35 mm is sandwiched, and using a universal testing machine RH-30 manufactured by Shimadzu Corporation, the bending radius is 0.25 mm with a load of 1 Ton. The bending process was performed. The test was performed using five samples for each sample so that the bend line was perpendicular to the rolling direction. Thereafter, the outside of the bent portion was observed with an SZH-type optical stereomicroscope made by Olympus Optical at a magnification of 40 times to investigate the occurrence of rough skin appearing at several times the crystal grain size.
[0054]
<Test results>
The results are shown in Table 9.
[0055]
[Table 9]

[0056]
No. having a crystal grain size of 20 μm or less. 27-1 to No. 2 In No. 27-4, the amount of stamping burrs generated is small, there is no occurrence of rough skin after the bending test, and there are good stamping properties and bending workability. On the other hand, No. whose crystal grain size exceeds 20 μm. 27-5 and no. In 27-6, the amount of stamping burrs suddenly increases, and rough skin after the bending test occurs.
[0057]
(Example 4)
<Production of sample>
No. 2 used in Example 2 was used. 27 samples were used. A test piece of 25 mm × 50 mm was cut out from a position 100 m from the outer periphery of the coil, and the surface roughness was changed by polishing with a cloth if the roughness was different. The sample whose roughness was adjusted was immersed in acetone and subjected to ultrasonic cleaning, followed by electrolytic degreasing to obtain a heated sample. The number of test pieces for each sample was five.
In addition, the surface of the test piece was measured with an X-ray photoelectron analyzer (VG ESCALAB-210D) before heating (Mg, Kα, 15 kV, 20 mA), and the initial oxidation state was investigated. The ratio (O1s) / (Cu2p) of the oxygen peak intensity to the copper peak intensity was 0.4 for each test piece, and the initial oxidation state was constant.
[0058]
<Test method>
The effect of surface roughness on oxide film adhesion was investigated by the following method.
[Surface roughness]
For each specimen ultrasonically cleaned with acetone, the roughness was measured by scanning the probe over a length of 5 mm in parallel to the rolling direction. Five specimens of each sample showed almost the same surface roughness. The average value of 5 data was used as the surface roughness of each sample. The surface roughness was measured using a stylus type surface roughness measuring instrument (manufactured by Taylor Hobson). The definition of surface roughness is based on JIS-B0601 (definition and display of surface roughness).
[0059]
[Oxide film adhesion]
A test piece of each surface roughness was placed on a hot plate (SEFI hot plate HHP-401) maintained at 300 ° C. and heated for 30 minutes. After elapse of a predetermined time, it was cooled to room temperature, a commercially available acetate adhesive tape (3M No. 810) was applied, and immediately peeled off, and the presence or absence of an oxide film on the tape adhesive surface was examined visually. The case where the oxide film did not adhere to the adhesive surface was evaluated as “◯”, and the case where the oxide film adhered as little as possible was evaluated as “X”. The heating and peeling test using a hot plate was performed in a room at 25 ° C. and a relative humidity of 60%.
[0060]
<Test results>
The results are shown in Table 10.
[0061]
[Table 10]

[0062]
The surface roughness is Ra: 0.2 μm or less, Rmax: 1.0 μm or less. 27-7 and no. In No. 27-8, the oxide film was not peeled off, but the surface roughness exceeded the above range. 27-9 and no. In 27-10, the oxide film peels off.
[0063]
【The invention's effect】
The copper alloy according to the present invention satisfies properties such as strength, electrical conductivity, and heat-resistant peelability of solder required for electric / electronic parts, and has stamping workability (stamping mold wear is small, generated burrs, Excellent in plating properties. Therefore, the present invention greatly contributes to improving the productivity and reliability of electric / electronic parts.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining a method of evaluating stress relaxation characteristics.
FIG. 2 is a side view thereof.
[Explanation of symbols]
1 Test piece

Claims (8)

Ni: 0.1-1.81 wt%, Si: 0.01-1.0 wt%, Zn: 0.01-5.0 wt%, S: 0.005 wt% or less, Se: 0.003 wt% % Or less, Te: 0.003 wt% or less, Sb: 0.003 wt% or less, Bi: 0.003 wt% or less of one or more elements selected from the group containing 0.005 wt% or less in total, A copper alloy for electrical and electronic parts having excellent stamping workability, wherein the balance is made of Cu and inevitable impurities. Ni: 0.1 to 1.81 wt%, Si: 0.01 to 1.0 wt%, Zn: 0.01 to 5.0 wt%, S: 0.0001 to 0.005 wt%, Se: One element selected from the group of 0.00003 to 0.003 wt%, Te: 0.00003 to 0.003 wt%, Sb: 0.00003 to 0.003 wt%, Bi: 0.00003 to 0.003 wt% Alternatively, a copper alloy for electric / electronic parts having excellent stamping workability, wherein 0.00003 to 0.005 wt% in total is contained in two or more kinds, and the balance is made of Cu and inevitable impurities.   Furthermore, it contains one or two elements selected from the group of Pb: 0.0001 to 0.05 wt% and C: 0.0001 to 0.01 wt% in total 0.0001 to 0.05 wt% The copper alloy for electrical / electronic parts which is excellent in stamping workability according to claim 1 or 2.   Furthermore, it contains 0.0001 to 0.3 wt% in total of one or two selected from the group of P: 0.0001 to 0.1 wt% and Al: 0.0005 to 0.3 wt%. The copper alloy for electric and electronic parts which is excellent in stamping workability as described in any one of Claims 1-3.   Furthermore, Mg: 0.001-1.5 wt% is contained, The copper alloy for electrical / electronic parts excellent in stamping workability described in any one of Claims 1-4 characterized by the above-mentioned.   Furthermore, Mn: 0.001 to 0.5 wt%, Fe: less than 0.001 to 0.03 wt%, Co: 0.001 to 0.1 wt%, Ag: 0.0003 to 0.1 wt%, Cr: 0. One or two or more selected from the group consisting of 0005 to 0.01 wt%, Zr: 0.0005 to 0.01 wt%, and Ti: 0.0005 to 0.01 wt% in total 0.0003 to 0.7 wt% The copper alloy for electrical / electronic parts excellent in stamping workability according to any one of claims 1 to 5, which is contained.   The copper alloy for electrical and electronic parts having excellent stamping workability according to any one of claims 1 to 6, further comprising an oxygen content of 30 ppm or less and a hydrogen content of 10 ppm or less.   Furthermore, Sn: 0.01-8.0wt% is contained, The copper alloy for electrical / electronic components excellent in stamping workability described in any one of Claims 1-7 characterized by the above-mentioned.

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