JP3564460B2 - Copper foil for printed wiring board and method for producing the same - Google Patents
Copper foil for printed wiring board and method for producing the same Download PDFInfo
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- JP3564460B2 JP3564460B2 JP2002066407A JP2002066407A JP3564460B2 JP 3564460 B2 JP3564460 B2 JP 3564460B2 JP 2002066407 A JP2002066407 A JP 2002066407A JP 2002066407 A JP2002066407 A JP 2002066407A JP 3564460 B2 JP3564460 B2 JP 3564460B2
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
- C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
- C23C28/321—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer with at least one metal alloy layer
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
- C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
- C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
- C23C2222/20—Use of solutions containing silanes
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- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Parts Printed On Printed Circuit Boards (AREA)
- Electroplating Methods And Accessories (AREA)
- Chemical Treatment Of Metals (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Manufacturing Of Printed Wiring (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明はプリント配線板用銅箔及びその製造方法に関するものであり、更に詳しくは銅箔の少なくとも一方の面にタングステンもしくはモリブデンを含有するニッケル−リン層から成る合金層を設け、更に該層上にクロメート皮膜層を施し、必要に応じて該クロメート皮膜層上にシランカップリング剤層を設ける事でアルカリエッチング液に対して可溶となり、更に耐薬品性、耐熱性に優れた高密度配線に適したプリント配線板用銅箔に関するものである。
【０００２】
プリント配線板はパソコン、携帯電話などの高密度配線を必要とする各種電気機器に広く用いられているが、この分野の近年の開発速度は他の産業分野に比べても格段に速く、それに伴い、プリント配線板に要求される品質も高くなってきている。
【０００３】
【従来の技術】
プリント配線板製造方法としてはアディティブ法、サブトラクティブ法があるが、前者が回路形成時に銅箔を使用しないのに対して、後者は銅張積層板形成後回路を印刷し、不要部分をエッチング除去する製法でこちらの方が主流である。プリント配線板に使用されている銅箔の基材と接着する面に対する要求特性は、多種多様であるが特に重要な特性は以下の三点である。
【０００４】
▲１▼基材との引き剥がし強さが十分であること。
▲２▼上記引き剥がし強さが過酷試験（薬品処理、長時間加熱処理）後も十分であること。
▲３▼高密度化するプリント配線板の狭小化に伴う絶縁特性の信頼性（エッチングの精度）
【０００５】
特に近年は通常よく使用するガラスエポキシ基材（ＦＲ−４）以外にハロゲンフリー基材、ガラスポリイミド基材、高Ｔｇ基材等が頻繁に使用される様になり銅箔に対する要求特性はますます厳しくなってきている。
【０００６】
上記特性を満足させる一般的な手段として、先ず、硫酸及び硫酸銅浴からの陰極電解により得られた未処理銅箔への粗面化処理がある。粗面化処理とは未処理銅箔の少なくとも一方の面を硫酸及び硫酸銅水溶液中で限界電流密度またはそれ以上で陰極電解し銅の突起物を析出させ、更に該層上に銅又は銅合金のカバーメッキを施すものである。この粗面化処理により銅箔表面の粗度は上昇し、その結果機械的投錨効果が高くなり、引き剥がし強さは格段に上昇する。
【０００７】
しかしながらこの粗面化処理により解決される問題は上記した銅箔要求特性の▲１▼のみであり、過酷試験後（特に長時間加熱試験後）の引き剥がし強さの劣化を抑制することは出来ない。
【０００８】
そこで更にこの粗面化処理上に基材樹脂と銅箔との反応を防ぐ為、異種金属あるいは銅合金の被覆バリアーを施すかあるいはまた種々の防錆処理が施されている。
【０００９】
例えば特公昭５１−３５７１１号は銅箔面に亜鉛、インジウム、黄銅等からなる群より選ばれた層を被覆すること、特公昭５３−３９３７６号には２層からなる電着銅層を設け、更に接着すべき基材に対して化学的活性を有しない金属からなる層、例えば亜鉛、真鍮、ニッケル、コバルト、クロム、カドミウム、スズ、及び青銅などの層を被覆すること。
【００１０】
また、特公平２−５１２７２号には球状または樹枝状の亜鉛を沈着させ、かつこの層を銅、砒素、ビスマス、真鍮、青銅、ニッケル、コバルト、もしくは亜鉛の一つ以上またはその合金を被覆する事、更に特公平２−５９６３９号には樹脂基材と接合する面に対しリン含有ニッケルの薄層を設け、かつ、該層上にクロメート処理を施すこと、更に特公平４−２６７９４号には銅箔の少なくとも一方の面にニッケル−モリブデン層を施し、該層上にクロメート処理を形成させることが提案されている。
【００１１】
しかしながら、これら従来の被覆バリアー層には以下に示すような問題点がある。
亜鉛、真鍮、亜鉛−ニッケル等、亜鉛を主とする層を有する銅箔を印刷回路に適用した場合、銅箔と基材との接着面及びその近傍は、耐塩酸性が非常に弱く、プリント配線板製造工程において、酸洗や各種活性処理液中に浸漬されているうちに、その界面部分の腐食抵抗が弱いため、引き剥がし強さの劣化が生じ、特に最近の導体幅の狭い回路の場合、熱的衝撃あるいは機械的衝撃などにより、導体の剥離、脱落現象を起こす可能性があるという欠点がある。
また、塩化第二銅エッチングでは、銅箔と基材の接着面が弱いためアンダーカッティングを生じるという欠点を有している。
【００１２】
ニッケル、錫は耐薬品性、耐熱性に優れ、一般的によく使用される塩化第二鉄や塩化第二銅のエッチング液には可溶であるものの、パターンめっき法等でよく使用されるアルカリエッチング液には不溶であり、電気絶縁性を損なうエッチング残（ステイン）を生じるという重大な欠点を有している。近年の回路の狭小化を考えた場合、塩化第二鉄、塩化第二銅でファインパターンが描けるのはもちろん必須条件であるが、レジストなどの多種多様化によりアルカリエッチング性も必須条件である。
【００１３】
また、コバルト単独層の場合はアルカリエッチング性は良好であるが、亜鉛程ではないが耐薬品性に問題があること、インジウムは高価であり、実工程を想定したときに実用的でない事、真鍮メッキは実用的な方法はシアン化物浴からの方法しかなく、環境上、作業上で大きな問題を抱えている事など問題がある。
【００１４】
リン含有ニッケルの薄層を設けた後、該層上にクロメート層を設けた銅箔は耐塩酸性、耐シアン性は良好であるものの、更に、長時間加熱処理後の引き剥がし強さの劣化を抑えるべくやや厚くメッキした場合、アルカリエッチング性が悪くなりステインが発生する。また、ニッケル−モリブデン層を施し、該層上にクロメート処理層を設けた銅箔は塩酸浸漬後の劣化率は確かに少ないがシアン化物浴浸漬後の劣化率は大きく改良を要する。
【００１５】
このように従来から提案されているバリアー層は基材樹脂に対する非反応性と耐薬品性を同時に満足させる事が難しく、プリント配線板の急速な高密度化や多様化には十分満足できていない。
【００１６】
【発明が解決しようとする課題】
そこでプリント配線板用銅箔として上記問題を全て解決するために様々な銅箔処理方法を検討した結果、銅箔の少なくとも一方の面にタングステンもしくはモリブデンを含有するニッケル−リン層からなる合金層を形成することが効果的であるとの知見を得、本発明を完成するに至った。
【００１７】
即ち本発明は銅箔の少なくとも一方の面にタングステンもしくはモリブデンを含有するニッケル−リン層からなる合金層を形成させることを特徴とするプリント配線板用銅箔、及びタングステンもしくはモリブデンとニッケル、リンを含む電解液を用い該電解液中で銅箔を陰極電解し、タングステンもしくはモリブデンを含有するニッケル−リン層からなる合金層を形成させた後、該層上にクロメート皮膜層を設け、更に必要に応じてシランカップリング剤処理を施しシランカップリング剤層を設ける事を特徴とするプリント配線板用銅箔の製造方法である。
【００１８】
【課題を解決するための手段】
本発明のタングステンもしくはモリブデンを含有するニッケル−リン層からなる合金層はそのいずれが欠けても目的とするバリアー層は得られない。
【００１９】
・ニッケル単独層の場合
耐塩酸性、耐シアン性は良好であるがアルカリエッチング性が悪く強度のステインを生じる。
【００２０】
・タングステン、モリブデン、リン単独層の場合
水溶液から単独で析出させることが出来ない。タングステン、モリブデン、リンは鉄属の誘導析出型であり、本発明の場合ニッケルが無いと析出しない。
【００２１】
・ニッケル−タングステン層の場合
ニッケル単独層に比べるとアルカリエッチング性は幾分良好であるがステインは生じる。また、このアルカリエッチング性を向上させるためにタングステンの析出量を多くした場合、メッキ性状が悪くなり、常態、薬品処理後の引き剥がし強さが弱くなる。
【００２２】
・ニッケル−モリブデン層の場合
アルカリエッチング性、耐塩酸性は良好であるが、耐シアン性が悪い。
【００２３】
・ニッケル−リン層の場合
耐塩酸性、耐シアン性は良好であるが、更に、長時間加熱処理後の引き剥がし強さの劣化を抑えるべくやや厚くメッキした場合、アルカリエッチング性が悪くなりステインが発生する。
【００２４】
以上の様に単独及び二元系合金層ではそれぞれ欠点があり、タングステンもしくはモリブデンを含有するニッケル−リン層からなる三元系合金層にする事でアルカリエッチング液に対して可溶となり耐薬品性、耐熱性を備えたプリント配線板用銅箔となる。
【００２５】
また、本発明バリアー層上にクロメート皮膜層を施す事により様々な特性が向上し、例えば、耐酸化性を向上させる、基材との接着力を向上させる為引き剥がし強さが強くなる、耐ブラウントランスファー性（ガラスエポキシ樹脂を用いたプリント回路で生じるエッチング基板面の変色、着色、汚れの事）を向上させる等の効果をもたらす。
【００２６】
また、このクロメート皮膜層を形成させる浴は公知のものでよく、例えばクロム酸、重クロム酸ナトリウム、重クロム酸カリウムなどの６価クロムを有する物であればよく、水溶液にして浸漬又は陰極電解により施す。
【００２７】
また、このクロム酸液はアルカリ性、酸性のどちらでもかまわない。上記２種類のクロム酸液はそれぞれ長所、短所があり、使用目的に応じて使い分ければよいが、アルカリ性クロム酸液を使用した場合酸性クロム酸液に比べクロメート皮膜層の耐食性がわずかに劣る、接合基材との接着性がわずかに劣ると言う欠点があるが本発明のバリアー層上にアルカリ性クロム酸液でクロメート皮膜層を施しても上記した問題は発生しない。
【００２８】
また、アルカリ性クロム酸液として特公昭５８−１５９５０号にある様な亜鉛イオン、６価クロムイオンを含むアルカリ性ジンククロメート液を使用してもよく、本クロム酸液を使用することで、クロム単独酸液からのクロメート皮膜層よりも耐酸化性を向上させる事が出来る。もちろん酸性クロム酸液を使用しても問題無く同様の結果が得られる。
【００２９】
また、クロメート皮膜層上にシランカップリング剤層を施すことにより常態時の引き剥がし強さを向上させるのみならず、過酷試験後の引き剥がし強さの劣化も押さえる事ができ、更に耐酸化性も向上させ、優れた汎用性を備えたプリント回路用銅箔となる。シランカップリング剤はエポキシ基、アミノ基、メルカプト基、ビニル基、メタクリロキシ基、スチリル基等多種あるがそれぞれ異なった特性を有し、また、基材との相性もあり、選択して使用する必要がある。
シランカップリング剤層の形成は水溶液として浸漬処理又はスプレー処理などにより施す。
【００３０】
本発明のバリアー層は通常のプリント配線板用銅箔として使用する銅箔であれば電解銅箔、圧延銅箔の種類を問わず使用できる。また、該層は銅箔特性を損なわない程度（基材との接着力を低下させない程度）に処理する必要があるが、好ましい処理量は１ｍｇ／ｍ２ から５００ｍｇ／ｍ２であり更に好ましくは３ｍｇ／ｍ２から３００ｍｇ／ｍ２である。
【００３１】
タングステンもしくはモリブデンを含有するニッケル−リン層が１ｍｇ／ｍ２以下の場合本発明のバリアー効果が十分に発揮できず、一方、５００ｍｇ／ｍ２以上の場合銅の純度が下がる、コスト高となり不経済である等の問題点が発生する。
【００３２】
また、本発明のタングステンもしくはモリブデンを含有するニッケル−リン層のニッケル、リン、タングステンもしくはモリブデンの好ましい含有量は（ｗｔ％＝重量％）
【００３３】
６０ｗｔ％≦ニッケル≦９９ｗｔ％
１ｗｔ％≦リン≦２０ｗｔ％
０．１ｗｔ％≦タングステン≦１０ｗｔ％もしくは
０．１ｗｔ％≦モリブデン≦２５ｗｔ％
であり、
【００３４】
更に好ましくは
８０ｗｔ％≦ニッケル≦９５ｗｔ％
３ｗｔ％≦リン≦１５ｗｔ％
０．４ｗｔ％≦タングステン≦５ｗｔ％もしくは
０．４ｗｔ％≦モリブデン≦２０ｗｔ％
である。
【００３５】
ニッケルはタングステンもしくはモリブデンを含有するニッケル−リン層中の含有量が６０ｗｔ％未満の場合、タングステン、モリブデンの析出量にもよるが、該バリアー層の耐薬品性が悪くなり塩酸、シアン化物浴浸漬後の劣化率が大きくなる。
一方、９９ｗｔ％を超える場合にはアルカリエッチング液に不溶又は溶けにくくなりステインを生じる。
【００３６】
リンは該バリアー層中の含有量が１ｗｔ％未満の場合、タングステンもしくはモリブデンの析出量にもよるがニッケルがアルカリエッチング液に不溶となりステインを生じる。一方、２０ｗｔ％を超える場合、タングステンもしくはモリブデンの析出量にもよるが過酷試験後（耐薬品、長時間加熱処理）の引き剥がし強さの劣化が大きくなる。
【００３７】
タングステンは該バリアー層中の含有量が０．１ｗｔ％未満の場合、長時間加熱処理後の引き剥がし強さの劣化率が大きくなる。一方、１０ｗｔ％を超える場合、ニッケル−リン−タングステン層のメッキ性状が悪くなり、常態、薬品処理後の引き剥がし強さが弱くなる。
【００３８】
モリブデンは該バリアー層中の含有率が０．１ｗｔ％未満の場合、ニッケルの析出量にもよるが長時間加熱処理後の引き剥がし強さの劣化が大きくなる。
一方、２５ｗｔ％を超える場合シアン化物浴浸漬後の劣化率が大きくなる。
【００３９】
また、該バリアー層を銅箔表面上に形成させる方法は公知の電気メッキ法、真空蒸着法、スパッタリング法等各種方法により形成可能であるが、工業上のラインに最適と思われるものは、水溶液電気メッキ法である。
その製造方法とはニッケル、リン、タングステンもしくはモリブデンを含む電解液中で銅箔を陰極電解することにより得られる。
【００４０】
メッキ電解液には酒石酸、クエン酸等のオキシカルボン酸浴、ピロリン酸浴、酢酸浴、シアン化浴等種々挙げられるが、コスト、浴管理、公害性、作業性等を考慮すると酢酸浴、クエン酸浴等が適当であるが特にこれに限定するものではない。
【００４１】
ニッケル、リン、タングステン、モリブデンの供給源としては以下のものが使用できる。但し、これに限定されるものではない。
ニッケルイオンの供給源としては硫酸ニッケル、硫酸ニッケルアンモニウム、塩化ニッケル、酢酸ニッケルなどが使用できる。
【００４２】
リンイオンの供給源としては亜リン酸ナトリウム、次亜リン酸ナトリウム、亜リン酸ニッケルなどが使用できる。
【００４３】
タングステンイオンの供給源としてはタングステン酸ナトリウム、タングステン酸カリウム、タングステン酸アンモニウム等が使用できる。
【００４４】
モリブデンイオンの供給源としてはモリブデン酸ナトリウム、モリブデン酸カリウム、モリブデン酸アンモニウムなどが使用できる。
【００４５】
また本発明浴の導電性の付与として硫酸ナトリウムを添加してもよい。
浴温度は特に定めないが経済面、作業面等を考慮した場合、常温から５０℃位までが好ましい。電流密度は０．１から１０Ａ／ｄｍ２ まで広範囲で使用可能であるが、これも実工程を考慮した場合、１から５Ａ／ｄｍ２ 位までが好ましい。
【００４６】
ｐＨは該バリアー層にタングステン、モリブデンを使用した場合で異なるが、タングステンを使用した場合のｐＨは４から６位がよく、モリブデンを使用した場合は１０から１１位がよい。
このｐＨの範囲では三元素の同時析出、バリアー特性、作業性のすべてが良いが、これもまた上記条件に限定されるものではない。また、陽極はステンレス、白金属元素等の不溶性陽極を用いるのが好ましい。
【００４７】
【発明の実施の形態】
以下に本発明の実施例と比較例を示す。
【００４８】
【実施例】
（実施例１〜９）
あらかじめ公知の方法で粗化処理した３５μｍ電解銅箔を用意し、本発明浴の温度を３０℃一定とし、表１に示す様な浴組成、ｐＨ（硫酸で調整）、及び電解条件で陽極に白金を使用して銅箔表面を陰極電解し、タングステン含有ニッケル−リン層を形成した後、水洗し、次いで該層上にクロメート皮膜層を形成した。クロメート皮膜層を形成したクロム酸液の組成と電解条件を以下に示す。
【００４９】
（Ａ浴）
重クロム酸ナトリウム ５ｇ／Ｌ
浴温 ３０℃
ｐＨ（水酸化ナトリウムで調整） １３．０
電流密度 ２Ａ／ｄｍ２
電解時間 ５秒
陽極 白金
【００５０】
上記アルカリ性クロム酸浴でクロメート皮膜層を形成した後、水洗し、次いでシランカップリング剤層を形成した。シランカップリング剤層を形成したシランカップリング剤種、浴組成及び形成方法を以下に示す。
【００５１】
（Ｂ浴）
γ−アミノプロピルトリエトキシシラン ２ｍＬ／Ｌ
浴温 ３０℃
浸漬時間 １５秒
【００５２】
上記シランカップリング剤浴でシランカップリング剤層を形成した後、乾燥させた。
次にこの銅箔をＦＲ−４グレードのエポキシ樹脂含浸ガラス基材に積層、成形して銅張積層板の各特性試験を行った。その結果を表２に示す。
【００５３】
（実施例１０，１１）
実施例１〜９に於いてシランカップリング剤層を設けなかったこと以外は同じ方法で処理を行い、同じ方法で評価を行った。その結果を表２に示す。
【００５４】
（実施例１２〜１９）
あらかじめ公知の方法で粗化処理した３５μｍ電解銅箔を用意し、本発明浴の温度を３０℃一定とし、表１に示す様な浴組成、ｐＨ（アンモニアで調整）、及び電解条件で陽極に白金を使用して銅箔表面を陰極電解し、モリブデン含有ニッケル−リン層を形成した。
【００５５】
その後Ａ浴、Ｂ浴を用いてクロメート皮膜層、シランカップリング剤層を形成した後、乾燥させた。尚、Ａ浴、Ｂ浴の処理条件は実施例１〜９と同様の方法で行った。
次にこの銅箔をＦＲ−４グレードのエポキシ樹脂含浸ガラス基材に積層、成形して銅張積層板の各特性試験を行った。その結果を表２に示す。
【００５６】
（実施例２０，２１）
実施例１２〜１９に於いてシランカップリング剤層を設けなかったこと以外は同じ方法で処理を行い、同じ方法で評価を行った。その結果を表２に示す。
【００５７】
【比較例】
（比較例１）
実施例と同様の３５μｍ電解銅箔を用意し、表１に示す様に
硫酸ニッケル・六水和物 ３０ｇ／Ｌ
酢酸ナトリウム・三水和物 １０ｇ／Ｌ
ｐＨ（硫酸で調整） ４．５
としこの浴において上記３５μｍ電解銅箔を浴温３０℃、電流密度２Ａ／ｄｍ２、電解時間２秒間陰極電解した他は実施例１〜９、１２〜１９と同じ処理工程を行い、同じ方法で銅張積層板を成形し、同じ方法で各特性試験を行った。その結果を表２に示す。
【００５８】
（比較例２）
実施例と同様の３５μｍ電解銅箔を用意し、表１に示す様に
硫酸ニッケル・六水和物 ３０ｇ／Ｌ
タングステン酸ナトリウム・二水和物 ２ｇ／Ｌ
酢酸ナトリウム・三水和物 １０ｇ／Ｌ
ｐＨ（硫酸で調整） ４．５
としこの浴において上記３５μｍ電解銅箔を浴温３０℃、電流密度２Ａ／ｄｍ２、電解時間２秒間陰極電解した他は実施例１〜９、１２〜１９と同じ処理工程を行い、同じ方法で銅張積層板を成形し、同じ方法で各特性試験を行った。その結果を表２に示す。
【００５９】
（比較例３）
実施例と同様の３５μｍ電解銅箔を用意し、表１に示す様に
硫酸ニッケル・六水和物 ３０ｇ／Ｌ
タングステン酸ナトリウム・二水和物 ２０ｇ／Ｌ
クエン酸三ナトリウム・二水和物 ３０ｇ／Ｌ
ｐＨ（硫酸で調整） ５．０
としこの浴において上記３５μｍ電解銅箔を浴温３０℃、電流密度２Ａ／ｄｍ２、電解時間３秒間陰極電解した他は実施例１〜９、１２〜１９と同じ処理工程を行い、同じ方法で銅張積層板を成形し、同じ方法で各特性試験を行った。その結果を表２に示す。
【００６０】
（比較例４）
実施例と同様の３５μｍ電解銅箔を用意し、表１に示す様に
硫酸ニッケル・六水和物 ３０ｇ／Ｌ
モリブデン酸ナトリウム・二水和物 ６０ｇ／Ｌ
クエン酸三ナトリウム・二水和物 ３０ｇ／Ｌ
ｐＨ（アンモニアで調整） １０．５
としこの浴において上記３５μｍ電解銅箔を浴温３０℃、電流密度２Ａ／ｄｍ２、電解時間２秒間陰極電解した他は実施例１〜９、１２〜１９と同じ処理工程を行い、同じ方法で銅張積層板を成形し、同じ方法で各特性試験を行った。その結果を表２に示す。
【００６１】
（比較例５）
実施例と同様の３５μｍ電解銅箔を用意し、表１に示す様に
硫酸ニッケル・六水和物 ３０ｇ／Ｌ
モリブデン酸ナトリウム・二水和物 ９０ｇ／Ｌ
クエン酸三ナトリウム・二水和物 ３０ｇ／Ｌ
ｐＨ（アンモニアで調整） １０．５
としこの浴において上記３５μｍ電解銅箔を浴温３０℃、電流密度４Ａ／ｄｍ２、電解時間２秒間陰極電解した他は実施例１〜９、１２〜１９と同じ処理工程を行い、同じ方法で銅張積層板を成形し、同じ方法で各特性試験を行った。その結果を表２に示す。
【００６２】
（比較例６）
実施例と同様の３５μｍ電解銅箔を用意し、表１に示す様に
硫酸ニッケル・六水和物 ３０ｇ／Ｌ
次亜リン酸ナトリウム・一水和物 ２ｇ／Ｌ
酢酸ナトリウム・三水和物 １０ｇ／Ｌ
ｐＨ（硫酸で調整） ４．５
としこの浴において上記３５μｍ電解銅箔を浴温３０℃、電流密度２Ａ／ｄｍ２、電解時間２秒間陰極電解した他は実施例１〜９、１２〜１９と同じ処理工程を行い、同じ方法で銅張積層板を成形し、同じ方法で各特性試験を行った。その結果を表２に示す。
【００６３】
（比較例７）
実施例と同様の３５μｍ電解銅箔を用意し、表１に示す様に
硫酸ニッケル・六水和物 ３０ｇ／Ｌ
次亜リン酸ナトリウム・一水和物 ２ｇ／Ｌ
クエン酸三ナトリウム・二水和物 ３０ｇ／Ｌ
ｐＨ（アンモニアで調整） １０．５
としこの浴において上記３５μｍ電解銅箔を浴温３０℃、電流密度４Ａ／ｄｍ２、電解時間３秒間陰極電解した他は実施例１〜９、１２〜１９と同じ処理工程を行い、同じ方法で銅張積層板を成形し、同じ方法で各特性試験を行った。その結果を表２に示す。
【００６４】
【表１】
【表２】
＊２ 引き剥がし強さは１ｍｍ幅で測定。その他条件はＪＩＳ−Ｃ−６４１８に準ずる。
＊３ 塩酸浸漬後の引き剥がし強さの劣化率は６Ｎ−ＨＣｌ水溶液に２５℃ −２０分間浸漬後の劣化率を求めた。
＊４ シアン化物浴浸漬後の引き剥がし強さの劣化率は１０％−ＫＣＮ水溶液に７０℃−３０分間浸漬後の劣化率を求めた。
＊５ 長時間加熱処理後の引き剥がし強さは１８０℃−４８時間加熱処理を行った後の引き剥がし強さを測定した。
＊６ アルカリエッチング
【００６７】
エッチング法
○：ステインが全く認められない
△：ステインがわずかに認められる
×：強度のステイン
【００６８】
表１にタングステンもしくはモリブデンを含有するニッケル−リン層及び該層上にクロメート皮膜層を施した後、更に該クロメート層上にシランカップリング剤層を施した実施例１〜９、１２〜１９とタングステンもしくはモリブデンを含有するニッケル−リン層及び該層上にクロメート皮膜層を施した実施例１０，１１、２０，２１と比較例１〜７のメッキ浴組成、ｐＨ、電解条件、シランカップリング剤層の有無、タングステンもしくはモリブデンを含有するニッケル−リン層の析出量（ｍｇ／ｍ２）及び該層中の各元素の含有率（ｗｔ％＝重量％）を示し、また、表２には上記実施例、比較例の各種特性を評価した結果を示した。
【００６９】
タングステンもしくはモリブデンを含有するニッケル−リン層及び該層上にクロメート皮膜層を施した後、更に該クロメート層上にシランカップリング剤層を施した実施例１〜９、１２〜１９は、エッチングに於いて金属選択性のあるアルカリエッチング液に対しても可溶であり、更に、塩酸浸漬後、シアン化物浴浸漬後の引き剥がし強さの劣化率も低く抑えられ、更に、長時間加熱処理後の引き剥がし強さも十分であり、優れた汎用性を備えたプリント回路用銅箔である事が分かる。
【００７０】
またタングステンもしくはモリブデンを含有するニッケル−リン層及び該層上にクロメート皮膜層を施した実施例１０，１１，２０，２１は各種引き剥がし強さに於いて上記実施例１〜９、１２〜１９に若干劣るものの十分に実用範囲内であり、タングステンもしくはモリブデンを含有するニッケル−リン層自身が優れたバリアー層であることが分かる。
【００７１】
一方、比較例１〜７までの単独層、２元系合金層について述べると、
・ニッケル単独層（比較例１）
アルカリエッチング性が悪く強度のステインを生じる。
・ニッケル−タングステン層（比較例２，３）
ニッケル単独層に比べるとアルカリエッチング性は幾分良好であるがそれでもステインは生じる。また、このアルカリエッチング性を向上させるためにタングステン析出量を増やすとメッキ性状が悪くなり、常態、薬品処理後の引き剥がし強さが弱くなる．
【００７２】
・ニッケル−モリブデン層（比較例４，５）
アルカリエッチング性、耐塩酸性は良好であるがシアン化物浴浸漬後の劣化率が大きい。
・ニッケル−リン層（比較例６，７）
長時間加熱処理後の引き剥がし強さの劣化が大きい。
また、アルカリエッチングに於いてステインの発生が確認できる。
という様にそれぞれ欠点があり、プリント配線板用銅箔として使用するには改良を要する。
【００７３】
【発明の効果】
以上の様に本発明のタングステンもしくはモリブデンを含有するニッケル−リン層は
▲１▼基材との引き剥がし強さが十分である。
▲２▼上記引き剥がし強さが過酷試験（薬品処理、加熱処理）後も十分である。
▲３▼高密度化する印刷回路の狭小化に伴う絶縁特性の信頼性。
【００７４】
以上の特性を全て十分に満たしており、狭小化著しいプリント配線板、特に高密度プリント配線板においてその性能を十分に発揮できるものである。
以上、アルカリエッチング液に対して可溶であり、更に耐薬品性、耐熱性に適した本発明プリント配線板用銅箔は一般のプリント配線板はもちろん高密度プリント配線板にも適したものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a copper foil for a printed wiring board and a method for producing the same, and more particularly, to an alloy layer comprising a nickel-phosphorus layer containing tungsten or molybdenum on at least one surface of the copper foil, and further comprising: By applying a chromate film layer to the chromate film layer and providing a silane coupling agent layer on the chromate film layer as necessary, it becomes soluble in alkali etching solution, and is used for high-density wiring with excellent chemical resistance and heat resistance. The present invention relates to a suitable copper foil for a printed wiring board.
[0002]
Printed wiring boards are widely used in various electrical devices that require high-density wiring such as personal computers and mobile phones, but the recent development speed in this field is much faster than in other industrial fields. Also, the quality required for printed wiring boards has been increasing.
[0003]
[Prior art]
Printed wiring board manufacturing methods include the additive method and the subtractive method.The former does not use copper foil when forming the circuit, while the latter prints the circuit after forming the copper-clad laminate and removes unnecessary parts by etching. This is the mainstream method of making. The required characteristics of the surface of the copper foil used for the printed wiring board that adheres to the base material are various, but particularly important characteristics are the following three points.
[0004]
(1) The peel strength with the base material is sufficient.
{Circle around (2)} The peel strength is sufficient even after a severe test (chemical treatment, long-time heat treatment).
(3) Reliability of insulation characteristics accompanying narrowing of printed wiring boards with higher density (etching accuracy)
[0005]
Particularly in recent years, in addition to the commonly used glass epoxy base material (FR-4), halogen-free base materials, glass polyimide base materials, high Tg base materials, etc. have been frequently used, and the required properties for copper foils are increasing. It is getting tougher.
[0006]
As a general means for satisfying the above characteristics, first, there is a roughening treatment on an untreated copper foil obtained by cathodic electrolysis from a sulfuric acid and copper sulfate bath. Roughening treatment means that at least one surface of the untreated copper foil is subjected to cathodic electrolysis at a critical current density or higher in an aqueous solution of sulfuric acid and copper sulfate to precipitate copper projections, and further, copper or copper alloy is formed on the layer. Cover plating. The surface roughening treatment increases the roughness of the copper foil surface, resulting in a higher mechanical anchoring effect, and a remarkable increase in peel strength.
[0007]
However, the problem solved by this surface roughening treatment is only the above-mentioned required property (1) of the copper foil, and the deterioration of the peeling strength after a severe test (particularly after a long-time heating test) cannot be suppressed. Absent.
[0008]
Therefore, in order to prevent a reaction between the base resin and the copper foil on the surface roughening treatment, a coating barrier of a different metal or a copper alloy is applied or various rust preventive treatments are applied.
[0009]
For example, JP-B-51-35711 covers a copper foil surface with a layer selected from the group consisting of zinc, indium, brass, etc., and JP-B-53-39376 provides an electrodeposited copper layer consisting of two layers. Furthermore, coating a layer of a metal having no chemical activity on the substrate to be adhered, such as a layer of zinc, brass, nickel, cobalt, chromium, cadmium, tin, and bronze.
[0010]
In Japanese Patent Publication No. 2-51272, spherical or dendritic zinc is deposited, and this layer is coated with one or more of copper, arsenic, bismuth, brass, bronze, nickel, cobalt, or zinc or an alloy thereof. In addition, Japanese Patent Publication No. 2-59639 discloses that a thin layer of phosphorus-containing nickel is provided on the surface to be bonded to the resin base material and that the layer is subjected to a chromate treatment. It has been proposed to apply a nickel-molybdenum layer on at least one side of the copper foil and form a chromate treatment on the layer.
[0011]
However, these conventional coating barrier layers have the following problems.
When a copper foil having a layer mainly composed of zinc, such as zinc, brass, zinc-nickel, etc. is applied to a printed circuit, the adhesion surface between the copper foil and the base material and the vicinity thereof have very low hydrochloric acid resistance, and the printed wiring is provided. In the board manufacturing process, while being immersed in pickling or various active treatment liquids, the corrosion resistance of the interface is weak, so the peeling strength is deteriorated, especially in recent circuits with narrow conductor width However, there is a drawback that the conductor may peel off or fall off due to thermal shock or mechanical shock.
In addition, cupric chloride etching has the disadvantage that undercutting occurs because the bonding surface between the copper foil and the substrate is weak.
[0012]
Nickel and tin are excellent in chemical resistance and heat resistance, and are soluble in commonly used ferric chloride and cupric chloride etching solutions, but are often used in pattern plating and other alkalis. It is insoluble in an etchant and has a serious disadvantage that an etching residue (stain) which impairs electrical insulation is generated. In consideration of recent circuit narrowing, it is an essential condition that a fine pattern can be drawn with ferric chloride and cupric chloride. However, alkali etching is also an essential condition due to the variety of resists and the like.
[0013]
In the case of a single layer of cobalt, the alkali etching property is good, but it is not as good as zinc, but there is a problem in chemical resistance, indium is expensive, and it is not practical when assuming the actual process, brass The only practical method for plating is from a cyanide bath, and there are problems such as having a large environmental and work problem.
[0014]
After providing a thin layer of phosphorous-containing nickel, the copper foil provided with a chromate layer on the layer has good hydrochloric acid resistance and cyanide resistance, but also has a deterioration in peel strength after long-time heat treatment. If the plating is made a little thicker to suppress, the alkali etching property will deteriorate and stain will occur. In addition, a copper foil having a nickel-molybdenum layer and a chromate-treated layer provided on the nickel-molybdenum layer has a small deterioration rate after immersion in hydrochloric acid, but requires a large improvement in the deterioration rate after immersion in a cyanide bath.
[0015]
As described above, it is difficult for the conventionally proposed barrier layer to simultaneously satisfy the non-reactivity with the base resin and the chemical resistance, and is not sufficiently satisfied with rapid densification and diversification of printed wiring boards. .
[0016]
[Problems to be solved by the invention]
Therefore, as a result of examining various copper foil processing methods to solve all of the above problems as a copper foil for a printed wiring board, an alloy layer made of a nickel-phosphorus layer containing tungsten or molybdenum was formed on at least one surface of the copper foil. The inventors have found that the formation is effective, and have completed the present invention.
[0017]
That is, the present invention provides a copper foil for a printed wiring board characterized by forming an alloy layer comprising a nickel-phosphorus layer containing tungsten or molybdenum on at least one surface of the copper foil, and tungsten or molybdenum and nickel, phosphorus. After performing a cathodic electrolysis of a copper foil in the electrolytic solution using the electrolytic solution containing, and forming an alloy layer composed of a nickel-phosphorus layer containing tungsten or molybdenum, a chromate film layer is provided on the layer, and further necessary. A method for producing a copper foil for a printed wiring board, characterized by providing a silane coupling agent layer by performing a silane coupling agent treatment accordingly.
[0018]
[Means for Solving the Problems]
If any of the alloy layers of the present invention comprising a nickel-phosphorus layer containing tungsten or molybdenum is missing, a desired barrier layer cannot be obtained.
[0019]
In the case of a nickel-only layer, the hydrochloric acid resistance and the cyan resistance are good, but the alkali etching property is poor and a strong stain is generated.
[0020]
-In the case of a single layer of tungsten, molybdenum, and phosphorus, it cannot be solely precipitated from an aqueous solution. Tungsten, molybdenum, and phosphorus are of the induction precipitation type of the iron group, and do not precipitate without nickel in the present invention.
[0021]
In the case of a nickel-tungsten layer, the alkali etching property is somewhat better than that of a nickel-only layer, but stain occurs. If the amount of tungsten deposited is increased in order to improve the alkali etching property, the plating properties are deteriorated, and the peeling strength after the chemical treatment under normal conditions is weakened.
[0022]
In the case of a nickel-molybdenum layer, alkali etching properties and hydrochloric acid resistance are good, but cyan resistance is poor.
[0023]
-In the case of a nickel-phosphorus layer, the hydrochloric acid resistance and cyan resistance are good, but if the plating is made slightly thicker to suppress the deterioration of the peeling strength after a long-time heat treatment, the alkali etching property becomes poor and the stain becomes poor. appear.
[0024]
As described above, the single and binary alloy layers have disadvantages, respectively. By forming a ternary alloy layer composed of a nickel-phosphorus layer containing tungsten or molybdenum, the alloy becomes soluble in an alkali etching solution and has chemical resistance. It becomes a copper foil for printed wiring boards having heat resistance.
[0025]
Further, by applying a chromate film layer on the barrier layer of the present invention, various properties are improved, for example, to improve oxidation resistance, to increase the peeling strength to improve the adhesion to the substrate, Effects such as improving brown transfer properties (discoloration, coloring, and dirt on the etching substrate surface generated in a printed circuit using a glass epoxy resin) are provided.
[0026]
The bath for forming the chromate film layer may be a known bath, for example, a bath having hexavalent chromium such as chromic acid, sodium dichromate, and potassium dichromate. Apply by
[0027]
This chromic acid solution may be either alkaline or acidic. The above two types of chromic acid solutions each have advantages and disadvantages, and may be used properly depending on the purpose of use.However, when an alkaline chromic acid solution is used, the corrosion resistance of the chromate film layer is slightly inferior to that of the acidic chromic acid solution. Although there is a disadvantage that the adhesion to the bonding substrate is slightly inferior, the above-mentioned problem does not occur even if a chromate film layer is formed on the barrier layer of the present invention with an alkaline chromic acid solution.
[0028]
As the alkaline chromic acid solution, an alkaline zinc chromate solution containing zinc ion and hexavalent chromium ion as disclosed in JP-B-58-15950 may be used. Oxidation resistance can be improved more than a chromate film layer from a liquid. Of course, similar results can be obtained without any problem even if an acidic chromic acid solution is used.
[0029]
In addition, by applying a silane coupling agent layer on the chromate film layer, not only can the peel strength under normal conditions be improved, but also the deterioration of the peel strength after a severe test can be suppressed. The resulting copper foil for printed circuits has excellent versatility. There are various types of silane coupling agents, such as epoxy group, amino group, mercapto group, vinyl group, methacryloxy group, styryl group, but each has different characteristics, and it has compatibility with the base material, so it must be selected and used There is.
The silane coupling agent layer is formed by dipping or spraying as an aqueous solution.
[0030]
The barrier layer of the present invention can be used regardless of the type of electrolytic copper foil or rolled copper foil as long as it is a copper foil used as a normal copper foil for printed wiring boards. Further, it is necessary to treat this layer to such an extent that the copper foil properties are not impaired (to such an extent that the adhesion to the substrate is not reduced), but the preferred treatment amount is from 1 mg / m 2 to 500 mg / m 2 , more preferably It is 3 mg / m 2 to 300 mg / m 2 .
[0031]
Tungsten or nickel containing molybdenum - if phosphorus layer is 1 mg / m 2 or less barrier effect of the present invention can not be sufficiently exhibited, whereas, 500 mg / m 2 or more when lowered the purity of copper, cost and becomes uneconomical And other problems occur.
[0032]
Further, the preferable content of nickel, phosphorus, tungsten or molybdenum in the nickel-phosphorus layer containing tungsten or molybdenum of the present invention is (wt% = wt%).
[0033]
60wt% ≦ nickel ≦ 99wt%
1 wt% ≤ phosphorus ≤ 20 wt%
0.1wt% ≦ tungsten ≦ 10wt% or 0.1wt% ≦ molybdenum ≦ 25wt%
And
[0034]
More preferably, 80 wt% ≦ nickel ≦ 95 wt%
3wt% ≦ phosphorus ≦ 15wt%
0.4wt% ≦ tungsten ≦ 5wt% or 0.4wt% ≦ molybdenum ≦ 20wt%
It is.
[0035]
If the content of nickel in the nickel-phosphorus layer containing tungsten or molybdenum is less than 60% by weight, the chemical resistance of the barrier layer is deteriorated, depending on the amount of tungsten and molybdenum deposited, but immersion in hydrochloric acid or a cyanide bath. The later deterioration rate increases.
On the other hand, if it exceeds 99 wt%, it becomes insoluble or hardly soluble in the alkali etching solution, and stains are generated.
[0036]
When the content of phosphorus in the barrier layer is less than 1 wt%, nickel is insoluble in the alkaline etching solution to generate stain, depending on the amount of tungsten or molybdenum deposited. On the other hand, when the content exceeds 20 wt%, the peel strength after the severe test (chemical resistance, long-time heat treatment) greatly deteriorates depending on the precipitation amount of tungsten or molybdenum.
[0037]
When the content of tungsten in the barrier layer is less than 0.1 wt%, the rate of deterioration of the peel strength after the long-time heat treatment increases. On the other hand, when the content exceeds 10 wt%, the plating properties of the nickel-phosphorus-tungsten layer are deteriorated, and the peeling strength after the chemical treatment under normal conditions is weakened.
[0038]
When the content of molybdenum in the barrier layer is less than 0.1 wt%, the peel strength after a long-time heat treatment is greatly deteriorated depending on the amount of nickel deposited.
On the other hand, if it exceeds 25 wt%, the deterioration rate after immersion in the cyanide bath increases.
[0039]
The barrier layer can be formed on the surface of the copper foil by various methods such as a known electroplating method, a vacuum deposition method, and a sputtering method. It is an electroplating method.
The manufacturing method is obtained by subjecting a copper foil to cathodic electrolysis in an electrolytic solution containing nickel, phosphorus, tungsten or molybdenum.
[0040]
Examples of the plating electrolyte include oxycarboxylic acid baths such as tartaric acid and citric acid, pyrophosphoric acid baths, acetic acid baths, cyanide baths, and the like. An acid bath or the like is suitable, but not particularly limited thereto.
[0041]
The following sources can be used as sources of nickel, phosphorus, tungsten, and molybdenum. However, it is not limited to this.
As a supply source of nickel ions, nickel sulfate, nickel ammonium sulfate, nickel chloride, nickel acetate, and the like can be used.
[0042]
As a source of phosphorus ions, sodium phosphite, sodium hypophosphite, nickel phosphite and the like can be used.
[0043]
As a source of tungsten ions, sodium tungstate, potassium tungstate, ammonium tungstate or the like can be used.
[0044]
As a supply source of molybdenum ions, sodium molybdate, potassium molybdate, ammonium molybdate and the like can be used.
[0045]
In addition, sodium sulfate may be added to impart conductivity to the bath of the present invention.
The bath temperature is not particularly defined, but is preferably from room temperature to about 50 ° C. in consideration of economical aspects, working aspects and the like. The current density can be used in a wide range from 0.1 to 10 A / dm 2 , but it is preferably from 1 to 5 A / dm 2 in consideration of the actual process.
[0046]
The pH differs depending on whether tungsten or molybdenum is used for the barrier layer, but the pH when using tungsten is preferably 4 to 6, and when using molybdenum, 10 to 11 is preferable.
In this pH range, simultaneous precipitation of three elements, barrier properties, and workability are all good, but these are not limited to the above conditions. In addition, it is preferable to use an insoluble anode such as stainless steel and a white metal element as the anode.
[0047]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, examples of the present invention and comparative examples will be described.
[0048]
【Example】
(Examples 1 to 9)
A 35 μm electrolytic copper foil roughened in advance by a known method is prepared, the temperature of the bath of the present invention is kept constant at 30 ° C., and the anode is formed with the bath composition, pH (adjusted with sulfuric acid), and electrolytic conditions as shown in Table 1. The surface of the copper foil was subjected to cathodic electrolysis using platinum to form a nickel-phosphorus layer containing tungsten, washed with water, and then a chromate film layer was formed on the layer. The composition of the chromic acid solution having the chromate film layer formed thereon and the electrolysis conditions are shown below.
[0049]
(A bath)
Sodium dichromate 5g / L
Bath temperature 30 ° C
pH (adjusted with sodium hydroxide) 13.0
Current density 2A / dm 2
Electrolysis time 5 seconds Anode Platinum
After a chromate film layer was formed in the above alkaline chromic acid bath, it was washed with water, and then a silane coupling agent layer was formed. The species of the silane coupling agent, the bath composition, and the method of forming the silane coupling agent layer are shown below.
[0051]
(B bath)
γ-aminopropyltriethoxysilane 2mL / L
Bath temperature 30 ° C
Immersion time 15 seconds
After a silane coupling agent layer was formed in the silane coupling agent bath, it was dried.
Next, this copper foil was laminated and molded on a FR-4 grade epoxy resin impregnated glass substrate, and each characteristic test of the copper clad laminate was performed. Table 2 shows the results.
[0053]
(Examples 10 and 11)
Processing was performed in the same manner as in Examples 1 to 9 except that the silane coupling agent layer was not provided, and evaluation was performed in the same manner. Table 2 shows the results.
[0054]
(Examples 12 to 19)
A 35 μm electrolytic copper foil roughened in advance by a known method is prepared, the temperature of the bath of the present invention is kept constant at 30 ° C., and the anode is formed with the bath composition, pH (adjusted with ammonia) and electrolysis conditions as shown in Table 1. The copper foil surface was subjected to cathodic electrolysis using platinum to form a molybdenum-containing nickel-phosphorus layer.
[0055]
Thereafter, a chromate film layer and a silane coupling agent layer were formed using baths A and B, and then dried. The treatment conditions for bath A and bath B were the same as in Examples 1 to 9.
Next, this copper foil was laminated and molded on a FR-4 grade epoxy resin impregnated glass substrate, and each characteristic test of the copper clad laminate was performed. Table 2 shows the results.
[0056]
(Examples 20 and 21)
Except that the silane coupling agent layer was not provided in Examples 12 to 19, the treatment was performed by the same method, and the evaluation was performed by the same method. Table 2 shows the results.
[0057]
[Comparative example]
(Comparative Example 1)
A 35 μm electrolytic copper foil similar to that in the example was prepared, and as shown in Table 1, nickel sulfate hexahydrate 30 g / L
Sodium acetate trihydrate 10g / L
pH (adjusted with sulfuric acid) 4.5
In this bath, the same processing steps as those of Examples 1 to 9 and 12 to 19 were performed except that the 35 μm electrolytic copper foil was subjected to cathodic electrolysis at a bath temperature of 30 ° C., a current density of 2 A / dm 2 , and an electrolysis time of 2 seconds. A copper-clad laminate was molded and each property test was performed in the same manner. Table 2 shows the results.
[0058]
(Comparative Example 2)
A 35 μm electrolytic copper foil similar to that in the example was prepared, and as shown in Table 1, nickel sulfate hexahydrate 30 g / L
Sodium tungstate dihydrate 2g / L
Sodium acetate trihydrate 10g / L
pH (adjusted with sulfuric acid) 4.5
In this bath, the same processing steps as those of Examples 1 to 9 and 12 to 19 were performed except that the 35 μm electrolytic copper foil was subjected to cathodic electrolysis at a bath temperature of 30 ° C., a current density of 2 A / dm 2 , and an electrolysis time of 2 seconds. A copper-clad laminate was molded and each property test was performed in the same manner. Table 2 shows the results.
[0059]
(Comparative Example 3)
A 35 μm electrolytic copper foil similar to that in the example was prepared, and as shown in Table 1, nickel sulfate hexahydrate 30 g / L
Sodium tungstate dihydrate 20g / L
Trisodium citrate dihydrate 30g / L
pH (adjusted with sulfuric acid) 5.0
In this bath, the same processing steps as in Examples 1 to 9 and 12 to 19 were performed, except that the 35 μm electrolytic copper foil was subjected to cathodic electrolysis at a bath temperature of 30 ° C., a current density of 2 A / dm 2 , and an electrolysis time of 3 seconds. A copper-clad laminate was molded and each property test was performed in the same manner. Table 2 shows the results.
[0060]
(Comparative Example 4)
A 35 μm electrolytic copper foil similar to that in the example was prepared, and as shown in Table 1, nickel sulfate hexahydrate 30 g / L
Sodium molybdate dihydrate 60g / L
Trisodium citrate dihydrate 30g / L
pH (adjusted with ammonia) 10.5
In this bath, the same processing steps as those of Examples 1 to 9 and 12 to 19 were performed except that the 35 μm electrolytic copper foil was subjected to cathodic electrolysis at a bath temperature of 30 ° C., a current density of 2 A / dm 2 , and an electrolysis time of 2 seconds. A copper-clad laminate was molded and each property test was performed in the same manner. Table 2 shows the results.
[0061]
(Comparative Example 5)
A 35 μm electrolytic copper foil similar to that in the example was prepared, and as shown in Table 1, nickel sulfate hexahydrate 30 g / L
Sodium molybdate dihydrate 90g / L
Trisodium citrate dihydrate 30g / L
pH (adjusted with ammonia) 10.5
In this bath, the same processing steps as in Examples 1 to 9 and 12 to 19 were performed, except that the 35 μm electrolytic copper foil was subjected to cathodic electrolysis at a bath temperature of 30 ° C., a current density of 4 A / dm 2 , and an electrolysis time of 2 seconds. A copper-clad laminate was molded and each property test was performed in the same manner. Table 2 shows the results.
[0062]
(Comparative Example 6)
A 35 μm electrolytic copper foil similar to that in the example was prepared, and as shown in Table 1, nickel sulfate hexahydrate 30 g / L
Sodium hypophosphite monohydrate 2g / L
Sodium acetate trihydrate 10g / L
pH (adjusted with sulfuric acid) 4.5
In this bath, the same processing steps as those of Examples 1 to 9 and 12 to 19 were performed except that the 35 μm electrolytic copper foil was subjected to cathodic electrolysis at a bath temperature of 30 ° C., a current density of 2 A / dm 2 , and an electrolysis time of 2 seconds. A copper-clad laminate was molded and each property test was performed in the same manner. Table 2 shows the results.
[0063]
(Comparative Example 7)
A 35 μm electrolytic copper foil similar to that in the example was prepared, and as shown in Table 1, nickel sulfate hexahydrate 30 g / L
Sodium hypophosphite monohydrate 2g / L
Trisodium citrate dihydrate 30g / L
pH (adjusted with ammonia) 10.5
In this bath, the same processing steps as in Examples 1 to 9 and 12 to 19 were performed, except that the 35 μm electrolytic copper foil was subjected to cathodic electrolysis at a bath temperature of 30 ° C., a current density of 4 A / dm 2 , and an electrolysis time of 3 seconds. A copper-clad laminate was molded and each property test was performed in the same manner. Table 2 shows the results.
[0064]
[Table 1]
[Table 2]
* 2 Peel strength is measured in 1mm width. Other conditions conform to JIS-C-6418.
* 3 Deterioration rate of peel strength after immersion in hydrochloric acid was determined by immersion in a 6N-HCl aqueous solution at 25 ° C. for 20 minutes.
* 4 The deterioration rate of the peeling strength after immersion in the cyanide bath was determined by immersing in a 10% -KCN aqueous solution at 70 ° C. for 30 minutes.
* 5 Peel strength after long-time heat treatment was measured by measuring the peel strength after heat treatment at 180 ° C. for 48 hours.
* 6 Alkali etching
Etching method
Tables 1 to 9 and 12 to 19 show a nickel-phosphorus layer containing tungsten or molybdenum and a chromate coating layer formed on the nickel-phosphorus layer, and then a silane coupling agent layer formed on the chromate layer. Nickel-phosphorus layer containing tungsten or molybdenum and plating bath compositions, pH, electrolysis conditions, silane coupling agents of Examples 10, 11, 20, 21 and Comparative Examples 1 to 7 in which a chromate film layer was formed on the layer. The presence or absence of a layer, the amount of precipitation of a nickel-phosphorous layer containing tungsten or molybdenum (mg / m 2 ) and the content of each element in the layer (wt% =% by weight) are shown. The results of evaluating various characteristics of the examples and comparative examples are shown.
[0069]
Examples 1 to 9 and 12 to 19, in which a nickel-phosphorus layer containing tungsten or molybdenum and a chromate film layer formed on the nickel-phosphorus layer, and then a silane coupling agent layer was further formed on the chromate layer, It is also soluble in alkali etching solutions with metal selectivity, furthermore, the rate of deterioration of the peel strength after immersion in hydrochloric acid and after immersion in a cyanide bath can be suppressed to a low level. It is understood that the copper foil for printed circuits has sufficient peeling strength and excellent versatility.
[0070]
Examples 10, 11, 20, and 21 in which a nickel-phosphorus layer containing tungsten or molybdenum and a chromate film layer formed on the nickel-phosphorus layer have various peel strengths. However, the nickel-phosphorus layer containing tungsten or molybdenum itself is an excellent barrier layer.
[0071]
On the other hand, when describing the single layer and the binary alloy layer of Comparative Examples 1 to 7,
-Nickel single layer (Comparative Example 1)
Poor alkali etching property, resulting in strong stain.
-Nickel-tungsten layer (Comparative Examples 2 and 3)
Alkaline etchability is somewhat better than a nickel-only layer, but stain still occurs. If the amount of tungsten deposited is increased in order to improve the alkali etching property, the plating properties deteriorate, and the peeling strength after the chemical treatment is reduced under normal conditions.
[0072]
-Nickel-molybdenum layer (Comparative Examples 4 and 5)
Although the alkali etching property and the hydrochloric acid resistance are good, the deterioration rate after immersion in a cyanide bath is large.
-Nickel-phosphorus layer (Comparative Examples 6, 7)
The peel strength after long-time heat treatment is greatly deteriorated.
Further, generation of stain can be confirmed in alkali etching.
Each of them has disadvantages, and requires improvement when used as a copper foil for a printed wiring board.
[0073]
【The invention's effect】
As described above, the nickel-phosphorus layer containing tungsten or molybdenum of the present invention has (1) sufficient peeling strength with the substrate.
{Circle around (2)} The peel strength is sufficient even after a severe test (chemical treatment, heat treatment).
(3) The reliability of the insulation characteristics associated with the narrowing of printed circuits that are becoming denser.
[0074]
It satisfies all of the above characteristics sufficiently, and can sufficiently exhibit its performance in a printed wiring board that is extremely narrow, particularly a high-density printed wiring board.
As described above, the copper foil for a printed wiring board of the present invention, which is soluble in an alkali etching solution and is more suitable for chemical resistance and heat resistance, is suitable for general printed wiring boards as well as high-density printed wiring boards. is there.
Claims (6)
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| JP2005206915A (en) * | 2004-01-26 | 2005-08-04 | Fukuda Metal Foil & Powder Co Ltd | Copper foil for printed circuited board, and its production method |
| JP2006210689A (en) * | 2005-01-28 | 2006-08-10 | Fukuda Metal Foil & Powder Co Ltd | Copper foil for high frequency printed wiring board and its production method |
| JP5137341B2 (en) * | 2006-06-27 | 2013-02-06 | 古河電気工業株式会社 | Surface treated copper foil |
| JP4912171B2 (en) * | 2007-01-30 | 2012-04-11 | 福田金属箔粉工業株式会社 | Surface-treated copper foil and method for producing the same |
| JP5634103B2 (en) * | 2010-04-06 | 2014-12-03 | 福田金属箔粉工業株式会社 | A treated copper foil for a copper clad laminate, a copper clad laminate obtained by bonding the treated copper foil to an insulating resin substrate, and a printed wiring board using the copper clad laminate. |
| JP5985812B2 (en) * | 2011-11-04 | 2016-09-06 | Ｊｘ金属株式会社 | Copper foil for printed circuit |
| JP6273317B2 (en) * | 2016-06-06 | 2018-01-31 | Ｊｘ金属株式会社 | Copper foil for printed circuit |
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