JP2004014611A

JP2004014611A - Insulation film with supports, multilayer printed circuit board, and its manufacturing method

Info

Publication number: JP2004014611A
Application number: JP2002162826A
Authority: JP
Inventors: Shin Takanezawa; 高根沢　伸; Takashi Morita; 森田　高示; Takako Watanabe; 渡▲辺▼　貴子
Original assignee: Hitachi Chemical Co Ltd
Current assignee: Showa Denko Materials Co Ltd
Priority date: 2002-06-04
Filing date: 2002-06-04
Publication date: 2004-01-15

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer printed circuit board having flame retardance without use of bromine compound likely influencing harmfully on environment, realizing high tensile elongation rate of an insulation resin coat having high thermal resistance for solder capable of corresponding to lead free aspect, and mechanical and thermal resistance for stress concentration, and capable of coping with fine interconnect wiring by making surface roughness Rz 1-3 μm after coarsenings. <P>SOLUTION: The multilayer printed circuit board with one side or both sides of its substrate having an internal layer circuit sequentially laminated by insulation layers and outer layer circuits includes the insulation resin layer made by hardened insulation resin composition comprising (A) epoxyide resin with biphenyl structure and novolac structure, (B) particulate matter of copolymerization object of acrylonitrile butadiene and mixture of linear polymer, (C) phosphorous included phenol resin, (D) thermosetting agent, and (E) inorganic filler. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、支持体付き絶縁フィルム、多層配線板およびその製造方法に関する。
【０００２】
【従来の技術】
多層配線板を製造するには、片面または両面に内層回路を形成した絶縁基板上に、プリプレグと呼ばれるガラス布にエポキシ樹脂を含浸し半硬化状態にした材料を銅箔と重ねて熱プレスにより積層一体化した後、ドリルで層間接続用のスルーホールと呼ばれる穴をあけ、スルーホール内壁と銅箔表面上に無電解めっきを行って、必要ならば更に電解めっきを行って回路導体として必要な厚さとした後、不要な銅を除去して多層配線板を製造するのが一般的であった。
ところで、近年、電子機器の小型化、軽量化、多機能化が一段と進み、これに伴い、ＬＳＩやチップ部品等の高集積化が進みその形態も多ピン化、小型化へと急速に変化している。この為、多層配線板は、電子部品の実装密度を向上するために、微細配線化の開発が進められている。これらの要求に合致する多層配線板の製造手法として、ガラスクロスを含まない絶縁樹脂をプリプレグの代わりに絶縁層として用い、必要な部分のみビアホールで接続しながら配線層を形成するビルドアップ方式の多層配線板があり、軽量化や小型化、微細化に適した手法として主流になりつつある。
【０００３】
また、環境意識の高まりから燃焼時に有害な物質を発生する可能性がある材料は電子部品も含めて規制する動きが活発になっている。従来の多層配線板には、燃焼時に有害な物質を発生する可能性があるブロム化合物が難燃化のために使用されてきたが近い将来使用が困難になると予想される。
さらに、電子部品を多層配線板に接続するために一般的に用いられるはんだも鉛を有さない鉛フリーはんだが実用化されつつある。この鉛フリーはんだは、従来の共晶はんだよりも使用温度が約２０〜３０℃高くなることから従来にもまして材料には高いはんだ耐熱性が必要になっている。
【０００４】
このように、多層配線板に要求される項目は年々厳しくなり、特に基板と回路を接続する重要な役割をもつ絶縁層は更なる高性能化が必要になる。
しかしながら、多層配線板の薄型化のためにガラスクロスを含まない絶縁樹脂層は、ガラスクロスを含まないために絶縁樹脂の機械的物性の善し悪しが多層配線板の特性に大きく影響する。具体的には、絶縁樹脂が硬くて伸びが小さく脆い性質の場合、多層配線板の製品サイズへの打ち抜き加工時の機械的なストレスにより絶縁樹脂にクラックや欠けが生じ導通あるいは絶縁信頼性に大きな支障を与えることになる。また、機器の小型化や多機能化を達成するために電子部品が面実装型へ移行することで絶縁樹脂と電子部品の距離が狭小化し、絶縁樹脂には電子部品の熱的な応力が集中しやすくなってきた。すなわち、絶縁樹脂が硬くて伸びが小さく脆い性質の場合は、電子部品やそれを多層配線板と接続させるはんだや銅の熱的な応力集中により絶縁樹脂内部やはんだや銅にクラックを発生しやすくさせてしまう。
このようなことから、絶縁樹脂には機械的や熱的な応力集中に耐えられるような変形すなわち引っ張り伸び率が大きい性質が要求されるようになってきた。
【０００５】
【発明が解決しようとする課題】
しかし、引っ張り伸び率を大きくする手法としては一般に熱可塑性の高分子量成分を導入する手法がとられるが高分子量成分を導入するとガラス転移点の低下は避けられないのが通例であった。
また、環境に影響しないようにブロム化合物を使用せずに、高いはんだ耐熱性を有する絶縁樹脂は現段階で開発されていないのが実状である。その理由としては、難燃剤を用いると絶縁樹脂全体の分解温度が低下しやすくなりはんだ付け温度での分解が進行してはんだ耐熱性が低下するからである。
さらに、電子機器の小型化、高機能化が進み配線板の微細化が進んでいる。この微細配線化には回路導体のエッチング精度の点から絶縁樹脂と回路導体を接着する界面の粗さをできるだけ小さく必要がある。このため、最近では銅箔メーカから銅箔の粗化後の表面粗さＲｚが従来の７〜８μｍから３〜４μｍのような低粗化箔が実用化されてきた。しかしながら、絶縁樹脂と回路導体を接着する界面の粗さは絶縁樹脂と回路導体との接着強度に重要な影響を与えており、界面の粗さが小さくなるほど接着強度は低下してしまう。このため、低粗さでも高い接着強度を発現できる絶縁樹脂が必要になっている。
【０００６】
本発明は、環境に悪影響を与える可能性があるブロム化合物を一切使用せずに難燃性を有し、鉛フリー化に対応可能な高いはんだ耐熱性と機械的や熱的な応力集中に耐えられるような絶縁樹脂の塗膜の高引っ張り伸び率を実現させ、かつ微細配線化に対応可能なように塗膜の接着強度を維持しつつ粗化後の粗さが低い絶縁樹脂を半硬化状態とした支持体付き絶縁フィルム、このフィルムを絶縁層に用いた多層配線板およびその製造方法を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明者らはこのような問題を解決するために研究を進めた結果、多層配線板における絶縁層として、ビフェニル構造及びノボラック構造を有したエポキシ樹脂とアクリロニトリルブタジエンの共重合物とリン含有フェノール樹脂と熱硬化剤と無機フィラーを必須として含んだ絶縁樹脂を用いれば、環境に悪影響を与える可能性があるブロム化合物を一切使用しないで難燃性を有し、鉛フリー化に対応可能な高いはんだ耐熱性と機械的や熱的な応力集中に耐えられるような絶縁樹脂塗膜の高引っ張り伸び率を実現させ、さらに多層配線板の微細配線化に対応可能なように粗化後の表面粗さをＲｚで１〜３μｍの範囲内にできることを見出した。
【０００８】
すなわち、（１）本発明の支持体付き絶縁フィルムは、（Ａ）ビフェニル構造及びノボラック構造を有したエポキシ樹脂と、（Ｂ）アクリロニトリルブタジエンの共重合物の粒子状物と線状ポリマの混合物と、（Ｃ）リン含有フェノール樹脂と、（Ｄ）熱硬化剤と、（Ｅ）無機フィラーとを含む絶縁樹脂組成物の半硬化状態のフィルムが支持体表面に形成されてなることを特徴とする支持体付き絶縁フィルムを要旨とする。
【０００９】
（２）本発明の第一の多層配線板は、内層回路を有する基板の片面または両面に絶縁層及び外層回路層が逐次積層されている多層配線板であって、
絶縁層が、（Ａ）ビフェニル構造及びノボラック構造を有したエポキシ樹脂と（Ｂ）アクリロニトリルブタジエンの共重合物の粒子状物と線状ポリマの混合物と（Ｃ）リン含有フェノール樹脂と（Ｄ）熱硬化剤と（Ｅ）無機フィラーとを含む絶縁樹脂組成物が硬化してなる絶縁樹脂層を含む多層配線板を要旨とする。
【００１０】
（３）本発明の第二の多層配線板は、内層回路を有する基板の片面または両面に絶縁層及び外層回路層が逐次積層されている多層配線板であって、絶縁層が、上記（１）の支持体付き絶縁フィルムのフィルムが硬化してなる絶縁樹脂層を含む多層配線板を要旨とする。
【００１１】
（４）前記（２）または（３）記載の多層配線板において、絶縁樹脂層の引っ張り伸び率が４％以上であることが好ましい。
（５）前記（２）〜（４）いずれか記載の多層配線板において、絶縁樹脂層の外層回路層との界面の表面粗さが、Ｒｚで１〜３であることが好ましい。
（６）前記（２）〜（５）いずれか記載の多層配線板において、前記（Ａ）ビフェニル構造及びノボラック構造を有したエポキシ樹脂が絶縁樹脂組成物の全固形分中の割合で３５〜６０重量％であり、かつ前記（Ａ）エポキシ樹脂と、（Ｂ）アクリロニトリルブタジエンの共重合物の粒子状物と線状ポリマの混合物との固形分配合比が重量比で８０／２０〜９５／５であることが好ましい。
（７）　前記（２）〜（６）のいずれか記載の多層配線板において、（Ｃ）リン含有フェノール樹脂中のリン含有量が（Ｅ）無機フィラーを除く前記絶縁樹脂組成物の固形分中で０．７〜３．０重量％であることが好ましい。
【００１２】
また、本発明の多層配線板の製造方法は（８）前記（２）〜（７）のいずれか記載の多層配線板を製造する方法であって、
（Ａ）ビフェニル構造及びノボラック構造を有したエポキシ樹脂と（Ｂ）アクリロニトリルブタジエンの共重合物の粒子状物と線状ポリマの混合物と（Ｃ）リン含有フェノール樹脂と（Ｄ）熱硬化剤と（Ｅ）無機フィラーとを含む絶縁樹脂組成物層を含む層を、内層回路を有する基板に積層する工程（イ）、
絶縁樹脂組成物を硬化して絶縁樹脂層を得る工程（ロ）、
絶縁樹脂層表面に外層回路層を形成する工程（ハ）、
を含む多層配線板の製造方法を要旨とする。
【００１３】
（９）　前記（８）記載の多層配線板の製造方法において、前記工程（ロ）では、絶縁樹脂層を得た後に絶縁樹脂層表面を酸化性粗化液で粗化処理する工程を含むことが好ましい。
（１０）　前記（８）または（９）記載の多層配線板の製造方法において、前記工程（ハ）では、銅めっきにより外層回路を形成することが好ましい。
（１１）　前記（８）〜（１０）のいずれか記載の多層配線板の製造方法において、前記工程（イ）では、絶縁樹脂組成物のワニスを支持体に塗布、乾燥して支持体付き絶縁層を作製し、この支持体付き絶縁フィルムを、内層回路を有する基板上に積層することが好ましい。
【００１４】
【発明の実施の形態】
まず、本発明における絶縁樹脂組成物およびそれを硬化させた絶縁樹脂の組成に付いて説明する。
（Ａ）ビフェニル構造及びノボラック構造を有したエポキシ樹脂とは、分子中にビフェニル誘導体の芳香族環を含有したノボラック構造のエポキシ樹脂であり、日本化薬株式会社製のＮＣ−３０００Ｓ（商品名）やＮＣ−３０００Ｓ−Ｈ（商品名）が使用できる。
【００１５】
（Ａ）ビフェニル構造及びノボラック構造を有したエポキシ樹脂の配合量は、溶剤を除いた絶縁樹脂組成物の全固形分中の割合で３５〜６０重量％であるのが好ましく、かつ（Ａ）ビフェニル構造及びノボラック構造を有したエポキシ樹脂と（Ｂ）アクリロニトリルブタジエン共重合物の粒子状物と線状ポリマの混合物との固形分配合比（重量比、以下同じ。）が８０／２０〜９５／５であるのが好ましい。前記（Ａ）成分の配合量が、３５重量％未満でははんだ耐熱性が低下し、６０重量％を超えると回路導体との接着強度が低下する傾向がある。また、（Ａ）成分と（Ｂ）成分との前記固形分配合比において、８０／２０よりも（Ａ）成分が減るとはんだ耐熱性が悪化し、逆に９５／５よりも（Ｂ）成分が増えると塗膜の引っ張り伸び率が低下する傾向がある。
【００１６】
（Ｂ）アクリロニトリルブタジエンの共重合物の粒子状物と線状ポリマとの混合物は、アクリロニトリルブタジエンの共重合物として、アクリロニトリルとブタジエンとを共重合したＮＢＲが挙げられ、アクリロニトリルとブタジエンとアクリル酸などのカルボン酸とを共重合したものも使用可能である。これらは、共重合する段階で架橋しないで得られる線状ＮＢＲと、部分的に架橋した粒子状ＮＢＲとの２種の混合物である。この混合物の配合割合は、固形分比で同量付近が全ての特性面で良好であるが、例えば前記アクリロニトリルとブタジエンとカルボン酸を共重合した混合物の場合、線状ＮＢＲと粒子状ＮＢＲとの配合比が３／７〜８／２までが好適に使用可能である。この場合、線状ＮＢＲが配合比で３／７よりも減ると絶縁樹脂を塗布、乾燥後の塗膜に凹凸が生じ、逆に８／２よりも増えると粗化後の粗さが大きくなり微細粗化形状に適さなくなる傾向がある。
【００１７】
（Ｃ）リン含有フェノール樹脂は、２官能フェノール樹脂と有機リン化合物を反応して得られたものであり、例えば、三光株式会社製のＨＣＡ−ＨＱ（商品名）等が使用できる。その含有量は、リン含有％が無機フィラーを除く絶縁樹脂組成物の固形分中で０．７〜３重量％の範囲になるようにするのが難燃性を発現するために好ましい。リン含有％が０．７％未満では難燃性の発現に不十分であり、リン含有％が３％を超えるとはんだ耐熱性が低下するためである。
【００１８】
（Ｄ）熱硬化剤は、ビフェニル構造及びノボラック構造を有したエポキシ樹脂中のエポキシ基とリン含有フェノール樹脂との反応促進のために使用される。熱硬化剤は、各種フェノール樹脂類、酸無水物類、アミン類、ヒドラジット類などが使用できる。フェノール樹脂類としては、ノボラック型フェノール樹脂、レゾール型フェノール樹脂などが使用でき、酸無水物類としては、無水フタル酸、ベンゾフェノンテトラカルボン酸二無水物、メチルハイミック酸等が使用でき、アミン類として、ジシアンジアミド、ジアミノジフェニルメタン、グアニル尿素等が使用できる。回路導体との接着性からジシアンジアミドが好ましく、耐熱性や絶縁性も考慮するとジシアンジアミドとノボラックフェノールを併用することがさらに好ましい。
これらの熱硬化剤は、エポキシ基に対して０．５〜１．５当量であるのが好ましい。熱硬化剤がエポキシ基に対して０．５当量未満の場合は外層銅との接着性が低下し、１．５当量を超えるとＴｇや絶縁性が低下する場合がある。
【００１９】
また、熱硬化剤の他に、必要に応じて反応促進剤を使用することができる。反応促進剤としては潜在性の熱硬化剤である各種イミダゾール類やＢＦ_３アミン錯体が使用できる。さらに好ましくは、絶縁樹脂組成物の保存安定性やＢステージ状（半硬化状）の絶縁樹脂組成物の取り扱い性及びはんだ耐熱性の点から２−フェニルイミダゾールや２−エチル−４−メチルイミダゾールが好ましく、その配合量はビフェニル構造及びノボラック構造を有したエポキシ樹脂の配合量に対して０．２〜０．６重量％が最適である。０．２重量％未満では、はんだ耐熱性が十分ではなく、０．６重量％を超えると絶縁樹脂組成物の保存安定性やＢステージ状の絶縁樹脂組成物の取り扱い性が低下するためである。
【００２０】
（Ｅ）無機フィラーは、例えばシリカ、溶融シリカ、タルク、アルミナ、水酸化アルミニウム、硫酸バリウム、水酸化カルシウム、エーロジル、炭酸カルシウムの中から選ばれるものが使用可能であり、これらは単独でもあるいは混合して用いても良い。なお、難燃性や低熱膨張の点から水酸化アルミニウムとシリカとを単独あるいは併用して用いるのが良い。またその配合量は、溶剤を除く絶縁樹脂組成物全体の固形分中で５〜３０ｖｏｌ％にするのが好ましい。さらに好ましくは、１０〜２０ｖｏｌ％であり、５ｖｏｌ％未満では外層回路導体との接着力が劣り、また３０ｖｏｌ％を超えると粗化後の表面粗さが大きくなることがあり、微細粗化形状に不適になる。
これらの無機フィラーは、分散性を高める目的でカップリング剤で処理しても良く、ニーダー、ボールミル、ビーズミル、３本ロール等既知の混練方法により分散しても良い。
【００２１】
本発明における絶縁樹脂組成物は、前記（Ａ）〜（Ｅ）の必須成分を配合して得られる他、通常の樹脂組成物に使用されるチキソ性付与剤、界面活性剤、カップリング剤等の各種添加剤を適宜配合できる。これらを充分に撹拌した後、泡がなくなるまで静置して絶縁樹脂組成物を得ることができる。
【００２２】
本発明における絶縁樹脂組成物は溶剤中で混合して希釈または分散させてワニスの形態とするのが作業性の点で好ましい。この溶剤には、メチルエチルケトン、キシレン、トルエン、アセトン、エチレングリコールモノエチルエーテル、シクロヘキサノン、エチルエトキシプロピオネート、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド等を使用できる。これらの溶剤は、単独あるいは混合系でも良い。この溶剤の前記樹脂組成物に対する割合は、従来使用している割合でよく、絶縁樹脂組成物の塗膜形成の設備にあわせてその使用量を調整する。
絶縁樹脂組成物をコンマコータでキャリアフィルムや銅箔に塗工する場合は、溶剤を除く樹脂組成物の固形分がワニス中３０〜６０重量％となるように溶剤の使用量を調節することが好ましい。
【００２３】
本発明の支持体付き絶縁フィルムは、上述の絶縁樹脂組成物の半硬化状態のフィルムが支持体表面に形成されてなることを特徴とする。
支持体付き絶縁フィルムを得るには、例えば、絶縁樹脂組成物のワニスを前記のように作製し、このワニスを支持体上に塗布し、乾燥する方法が挙げられる。また、ワニスを支持体上に塗布する場合はコンマコータ、バーコータ、キスコータ、ロールコーター等が利用でき、絶縁フィルムの厚みによって適宜使用される。塗布厚、塗布後の乾燥条件等は使用目的に合わせて適宜選択されるため特に制限するものではないが、一般にワニスに使用した溶剤が８０重量％以上揮発していることが好ましい。
絶縁フィルムが表面に形成される支持体としては、ＰＥＴ等のプラスチックフィルムや金属箔等が挙げられ、絶縁フィルム硬化後に支持体を剥離除去する場合は離型性のプラスチックフィルム等が好ましい。
【００２４】
本発明の多層配線板は、内層回路を有する基板の片面または両面に絶縁層及び外層回路層が逐次積層されている。そして、絶縁層には、前記絶縁樹脂組成物が硬化してなる絶縁樹脂層が含まれることを特徴とする。前記絶縁樹脂組成物は多層配線板作製時の熱履歴により硬化される。
また、絶縁樹脂層が、前記本発明の支持体付き絶縁フィルムのフィルムが硬化してなる絶縁樹脂層であってもよい。
【００２５】
本発明における絶縁樹脂層の、引っ張り伸び率は４％以上が好ましい。なお、上限は、他の特性に支障が生じない限り、特に制限するものではない。４％よりも低いと機械的または熱的な応力集中に耐えられるような変形が少なくなるため、電子部品やそれを多層配線板と接続させるはんだや銅の熱的な応力集中により絶縁樹脂内部にクラックを発生しやすくなる傾向がある。
本発明における絶縁樹脂層の粗化処理後の表面粗さは、Ｒｚが１〜３の範囲内であるのが好ましい。
なお、本発明における引っ張り伸び率とは、引張り試験機によって膜状の試料を一定速度で引張ったときに試料が伸びる割合、すなわち、例えば厚さ５０μｍの試料を１０ｍｍ×１００ｍｍの短冊状に切断し、長尺方向の両端１０ｍｍを固定して５ｍｍ／分の速度で引張った場合に、試料が切断されるまでに試料が伸びる割合を示す。
また、Ｒｚは、表面粗さの内、十点平均粗さ、すなわち対象物表面の抜き取り部分中で、最高から五番目までの山頂の平均線からの絶対値の平均値と、最低から五番目までの谷底の平均線からの絶対値の平均値との和を示すパラメータである（ＪＩＳ　Ｂ０６０１）。本発明では抜き取り部分１４９μｍからＲｚ（μｍ）を得た。
【００２６】
本発明の多層配線板は、次のような本発明の多層配線板の製造方法により製造することができる。
図１を参照して、前記の絶縁樹脂組成物を用いて多層配線板を製造する工程を説明する。図１の（ａ）〜（ｉ）は多層配線板を製造する工程の一例を説明する断面図である。
まず、絶縁基板２上に第一の回路層１ａを形成した回路板３を用意する［図１（ａ）参照］。
回路板は、例えば、第一の回路層（内層配線）が表面に形成された内層基板であり、内層基板として、通常の配線板において用いられている公知の積層板、例えば、ガラス布−エポキシ樹脂、紙−フェノール樹脂、紙−エポキシ樹脂、ガラス布・ガラス紙−エポキシ樹脂等が使用でき特に制限はない。また、ビスマレイミド−トリアジン樹脂を含浸させたＢＴ基板、さらにはポリイミドフィルムを基材として用いたポリイミドフィルム基板等も用いることができる。
【００２７】
また、回路層１ａを形成するための方法についても特に制限はなく、銅箔と前記絶縁基板を張り合わせた銅張り積層板を用い、銅箔の不要な部分をエッチング除去するサブトラクティブ法や、前記絶縁基板の必要な個所に無電解めっきによって回路を形成するアディティブ法等、公知の配線板の製造方法を用いることができる。
【００２８】
また、図１（ａ）には絶縁基板２の片面に回路層１ａを形成した例を示すが、両面銅張積層板を用いて回路層１ａを絶縁基板２の両面に形成することもできる。
【００２９】
次に、必要に応じて回路層１ａの表面を接着性に適した状態に表面処理する。この手法も、特に制限はなく、例えば、次亜塩素酸ナトリウムのアルカリ水溶液により回路層１ａの表面に酸化銅の針状結晶を形成し、形成した酸化銅の針状結晶をジメチルアミンボラン水溶液に浸漬して還元するなど公知の製造方法を用いることができる。
【００３０】
（イ）そして、回路層１ａを有する回路板３の片面若しくは両面に絶縁樹脂組成物層４ｂを形成する［図１（ｂ）参照］。図１（ｂ）では、回路層１ａは回路板３の片面に形成されているが、両面に形成されていても良く、この場合は絶縁樹脂組成物層４ｂを回路板３の両面に形成できる。また、この形成方法に特に制限はない。例えば、前記本発明の支持体付き絶縁フィルムを回路板３に積層して形成する方法が挙げられる。また、直接回路層１ａを有する回路板３の片面若しくは両面にカーテンコートやロールコーターを用いて塗工して層を形成する方法が挙げられる。
【００３１】
ワニスを回路板上に塗布する場合はバーコート、スピンコート、スクリーン印刷など一般の塗布方法が使用できる。何れの場合も塗布厚、塗布後の乾燥条件等は特に制限するものではないが、ワニスに使用した溶剤が８０重量％以上揮発していることが好ましい。
支持体付き絶縁フィルムを用いる場合、ワニスが塗布される支持体としては、ＰＥＴ等のプラスチックフィルムや金属箔等が挙げられ、ワニス硬化後に支持体を剥離除去する場合は離型性のプラスチックフィルム等が好ましい。また、支持体が銅箔等金属箔の場合は、剥離せずに後述する第二の回路層として引き続き用いることができる。支持体付き絶縁フィルムは、絶縁樹脂組成物層を回路板の回路層と接する面側に向け、ラミネート法やプレス装置を用いて回路板３に積層される。
【００３２】
（ロ）その後、絶縁樹脂組成物層を加熱硬化させて絶縁樹脂層である第一の絶縁層６ｃとするが［図１（ｃ）参照］、その硬化温度は後のめっき処理や銅のアニール処理などを考慮した温度や時間で行う。すなわち、あまり硬化を進めると後のめっき処理時に銅との接着性が低下したり、反面硬化が足りないとめっき処理時のアルカリ処理液に浸食されめっき液に溶解するような現象が生じたりする。これらのことを考慮すると、１５０〜１９０℃で３０〜９０分間の熱処理を与えて硬化するのが望ましい。
前記支持体付き絶縁フィルムを使用した場合は、加圧積層工程と加熱硬化工程とは同時でも別でもよい。加圧積層条件は、半硬化状態の絶縁樹脂組成物に回路層１ａの凹凸が埋め込まれれば良く、通常０．５〜２０ＭＰａが好ましい。
【００３３】
さらに、内層回路である第一の回路層１ａと外層回路を層間接続するために第一の絶縁層６ｃにビアホール５ｃを形成することもできる［図１（ｃ）参照］。このビアホールの形成手法として特に制限はなく、レーザ法やサンドブラスト法などを用いることができる。
【００３４】
（ハ）次に、以下のような回路加工を施すことにより第二の回路層１ｄを形成し、さらに第一の回路層１ａと第二の回路層１ｄとの層間接続を形成する［図１（ｄ）参照］。
まず、外層回路である第二の回路層１ｄを第一の絶縁層６ｃ上にめっき法で形成する場合は、第一の絶縁層６ｃを粗化処理するのが好ましい。粗化液としては、クロム／硫酸粗化液、アルカリ過マンガン酸粗化液、フッ化ナトリウム／クロム／硫酸粗化液、ホウフッ酸粗化液などの酸化性粗化液を用いることができる。粗化処理としては、例えば、先ず膨潤液として、ジエチレングリコールモノブチルエーテルとＮａＯＨとの水溶液を７０℃に加温して第一の絶縁層６ｃを５分間浸漬処理する。次に、粗化液として、ＫＭｎＯとＮａＯＨとの水溶液を８０℃に加温して１０分間浸漬処理する。引き続き、中和液、例えば塩化第一錫（ＳｎＣｌ_２）の塩酸水溶液に室温で５分間浸漬処理して中和する。
【００３５】
粗化処理後、パラジウムを付着させるめっき触媒付与処理を行う。めっき触媒処理は、塩化パラジウム系のめっき触媒液に浸漬して行われる。
次に、無電解めっき液に浸漬して第一の絶縁層６ｃ表面全面（ビアホールを形成した場合はビアホール内面を含む）に厚さが０．３〜１．５μｍの無電解めっき層（導体層）を析出させる。必要により、更に電気めっきを行って必要な厚さとする。無電解めっきに使用する無電解めっき液は、公知の無電解めっき液を使用することができ、特に制限はない。また、電気めっきについても公知の方法によることができ特に制限はない。これらのメッキは銅メッキであることが好ましい。
さらに不要な箇所をエッチング除去して第二の回路層１ｄと第一の回路層１ａ及び第二の回路層１ｄの層間接続とを形成することができる。
【００３６】
また、絶縁樹脂組成物層の形成に銅箔付絶縁フィルムを用いた場合は、外層回路（第二の回路層１ｄ）をエッチング法を用いて形成する。このエッチング法を用いる手法に特に制限はなく、厚み３μｍ程度の極薄銅箔を用いてパターンめっき法も用いることができる。この銅箔付絶縁フィルムを用いた場合の層間接続は、レーザ法等の方法でビアホールを設けた後、メッキ等により形成できる。
なお、第二の回路層１ｄを形成するための手法としては、前記の粗化した絶縁層表面に無電解めっき用の触媒を付与して全面に無電解めっき銅を析出させ、必要な場合には電気めっきによって回路導体を必要な厚さにして、不要な箇所をエッチング除去して形成する方法の他に、めっき触媒を含有した絶縁層を用いて、めっきレジストを形成して必要な箇所のみ無電解めっきにより回路形成する方法、及びめっき触媒を含有しない絶縁層を粗化し、めっき触媒を付与した後めっきレジストを形成して必要な箇所のみ無電解めっきにより回路形成する方法等を用いることができる。
【００３７】
さらに、第一の回路層１ａの表面処理と同様にして第二の回路層１ｄの表面処理を行い、前記絶縁樹脂組成物層４ｂの形成と同様にして絶縁樹脂組成物層４ｅを形成する［図１（ｅ）参照］。次いで、絶縁樹脂組成物層４ｅを硬化させて第二の絶縁層６ｆとし、また、ビアホール５ｆを形成する［図１（ｆ）参照］。さらに、同様にして第三の回路層１ｇを形成する［図１（ｇ）参照］。
以下、更に同様の工程を繰り返して層数の多い多層配線板を製造できる。
【００３８】
【実施例】
次に実施例により本発明を説明するが、本発明の範囲はこれらの実施例に限定されるものではない。
（実施例１）
（１）ガラス布基材エポキシ樹脂両面銅張積層板［銅箔の厚さ１８μｍ、基板厚み０．８ｍｍｔ、両面粗化箔を両面に有する日立化成工業株式会社製ＭＣＬ−Ｅ−６７（商品名）］の片面にエッチングを施して片面に回路層（以下、第一の回路層とする。）を有する回路板を作製した。
【００３９】
（２）下記組成の絶縁樹脂組成物のワニスを作製した。この時のエポキシに対する熱硬化剤の当量は１．０当量とした。この絶縁樹脂組成物のワニスをＰＥＴフィルム上に塗工し、１００℃−１０分乾燥して膜厚５０±３μｍの支持体付絶縁フィルムのロールを作製した。さらに、この支持体付絶縁フィルムと前記回路板を、絶縁樹脂組成物層を回路板の第一の回路層と接する面側にしてバッチ式真空加圧ラミネーターＭＶＬＰ−５００（名機株式会社製、商品名）を用いて積層した。
【００４０】
［組成］
・（Ａ）ビフェニル構造及びノボラック構造を有したエポキシ樹脂：ＮＣ３０００Ｓ−Ｈ
（日本化薬株式会社社製、商品名）　　　　　　　８２重量部
・（Ｂ）カルボン酸変性アクリロニトリルブタジエンゴム（線状ＮＢＲ）のＰＮＲ−１Ｈ　（ＪＳＲ株式会社製、商品名）と粒子状ＮＢＲのＸＥＲ−９１　（ＪＳＲ株式会社、商品名）を固形分比で１対１で混合した混合物　　　　１２重量部
・（Ｃ）リン含有フェノール樹脂：ＨＣＡ−ＨＱ
（三光株式会社製、商品名）　　　　　　　　　２８重量部
・（Ｄ）熱硬化剤：ジシアンジアミド　（日本カーバイド株式会社製）
１重量部
・（Ｄ）熱硬化剤：ノボラックフェノール樹脂（ＨＰ−８５０）
（日立化成工業株式会社製、商品名）　　　　　　５重量部
・反応促進剤：２−フェニルイミダゾール
（四国化成工業株式会社製、商品名２ＰＺ）　　　０．３重量部
・（Ｅ）無機フィラー：水酸化アルミニウム（ハイジライトＨ−４２Ｍ）
（昭和電工株式会社製、商品名）　　　　　　　２２重量部
・（Ｅ）無機フィラー：球状シリカ（アドマファインＳＯ−２５Ｒ）
（株式会社アドマテックス社製、商品名）　　　２０重量部
・溶剤：メチルエチルケトン　　　　　　　　　　４０重量部
・溶剤：ジメチルホルムアミド　　　　　　　　　２６重量部
【００４１】
（３）次に、ＰＥＴフィルムを剥がした後、１８０℃―６０分の硬化条件で前記絶縁樹脂組成物層を硬化して第一の絶縁層を得た。
（４）この第一の絶縁層に層間接続用のビアホールを日立ビアメカニクス製ＣＯ_２レーザ加工機（ＬＣＯ−１Ｂ２１型）を使用し、ビーム径８０μｍ、周波数５００Ｈｚでパルス幅５μｓｅｃ、ショット数７の条件で加工して作製した。
【００４２】
（５）第一の絶縁層を化学粗化するために、膨潤液として、ジエチレングリコールモノブチルエーテル：２００ｍｌ／Ｌ、ＮａＯＨ：５ｇ／Ｌの水溶液を作製し、７０℃に加温して５分間浸漬処理した。次に、粗化液として、ＫＭｎＯ_４：６０ｇ／Ｌ、ＮａＯＨ：４０ｇ／Ｌの水溶液を作製し、８０℃に加温して１０分間浸漬処理した。引き続き、中和液（ＳｎＣｌ_２：３０ｇ／Ｌ、ＨＣｌ：３００ｍｌ／Ｌ）の水溶液に室温で５分間浸漬処理して中和した。
【００４３】
（６）第一の絶縁層表面に第二の回路層を形成するために、まず、ＰｄＣｌ_２を含む無電解めっき用触媒であるＨＳ−２０２Ｂ（日立化成工業株式会社製、商品名）に、室温−１０分間浸漬処理し、水洗し、無電解銅めっき用であるめっき液ＣＵＳＴ−２０１（日立化成工業株式会社製、商品名）に室温−１５分間浸漬し、さらに硫酸銅電解めっきを行った。その後、アニールを１８０℃−３０分間行い第一の絶縁層表面およびビアホール内に厚さ２０μｍの導体層を形成した。
次に、めっき導体の不要な箇所をエッチング除去するために、まず銅表面の酸化皮膜を＃６００のバフロール研磨で除去した後、エッチングレジストを形成し、次いでエッチングし、その後エッチングレジストを除去して、第一の回路層と接続したバイアホールを含む第二の回路形成を行った。
【００４４】
（７）さらに、多層化するために、第二の回路導体表面を、亜塩素酸ナトリウム：５０ｇ／ｌ、ＮａＯＨ：２０ｇ／ｌ、リン酸三ナトリウム：１０ｇ／ｌの水溶液に８５℃−２０分間浸漬し、水洗して、８０℃−２０分間乾燥して第二の回路導体表面上に酸化銅の凹凸を形成した。
（８）前記（２）〜（７）の工程を繰り返して三層の多層配線板を作製した。
【００４５】
（実施例２）
実施例１において、無機フィラーを水酸化アルミニウムを用いずに球状シリカ（アドマファインＳＯ−２５Ｒ）単独とし、配合量を３２重量部とした。その他は実施例１と同様にして行った。
【００４６】
（実施例３）
実施例１において、支持体付絶縁フィルムを作製して該フィルムを第一の回路層に積層する代わりに、絶縁樹脂組成物のワニスを直接、回路板の第一の回路層を有する面側にロールコーターにより塗布し、１１０℃で１０分間乾燥して膜厚５０±３μｍの絶縁樹脂組成物層を形成した。その他は、実施例１と同様にして行った。
【００４７】
（実施例４）
実施例１において、配合量は同じのままカルボン酸変性アクリロニトリルブタジエンゴム（線状ＮＢＲ）のＰＮＲ−１Ｈ　（ＪＳＲ株式会社、商品名）をアクリロニトリルブタジエンゴム（線状ＮＢＲ）のＮ−２２０Ｓ　（ＪＳＲ株式会社、商品名）に置き換えた。その他は実施例１と同様にして行った。
【００４８】
（比較例１）
実施例１において、エポキシ樹脂を配合量は同じ８２重量部のままオルソクレゾールノボラック樹脂のＹＤＣＮ−７０２（東都化成株式会社商品名）に置き換え、熱硬化剤の当量を実施例１に近いものとするため、ジシアンジアミドの配合量を２．９重量部、ノボラックフェノール樹脂の配合量を７重量部とした。その他は実施例１と同様にして行った。
【００４９】
（比較例２）
実施例１において、粒子状ＮＢＲのＸＥＲ−９１　（ＪＳＲ株式会社、商品名）を用いずに、カルボン酸変性アクリロニトリルブタジエンゴム（線状ＮＢＲ）のＰＮＲ−１Ｈを１２重量部とした。その他は、実施例１と同様にして行った。
【００５０】
以上のようにして作製した樹脂組成物のワニス及び多層配線板について、▲１▼難燃性、▲２▼絶縁樹脂塗膜の引っ張り伸び率、▲３▼絶縁樹脂の粗化後の表面粗さ、▲４▼外層回路との接着強度、▲５▼絶縁樹脂の冷熱サイクル試験下でのクラック発生率、▲６▼不飽和雰囲気下での絶縁信頼性加速試験、▲７▼２８８℃はんだ耐熱性試験を実施した。その結果を表１に示す。
［難燃性］
各実施例及び比較例において内層の回路板として用いた、前記ガラス布基材エポキシ樹脂両面銅張積層板にエッチングを施して銅箔を完全に剥離した基板を作製し、この基板の両面に、片側の絶縁樹脂厚１５０μｍとなるように前記ワニスを塗布して絶縁樹脂組成物層を形成した。そして、１８０℃−１時間後加熱を行うことにより、難燃性の試験片を作製した。試験法は、ＵＬ−９４法に従い試験した。
【００５１】
［塗膜の引っ張り伸び率］
各実施例及び比較例におけるワニスを銅箔に塗工し、配線板作製と同様の１８０℃―６０分の熱処理を加えて硬化した。そして、銅をエッチング除去して硬化した絶縁樹脂塗膜を得た。この絶縁樹脂塗膜を厚さ５０μｍ、幅１０ｍｍ、長さ１００ｍｍに切断し、引張り速度約５ｍｍ／分でオートグラフ引っ張り試験（チャック間距離５０ｍｍ）により、絶縁樹脂塗膜を引っ張り、破断するまでの引っ張り伸び率を求めた。
【００５２】
［粗化後の表面粗さ：Ｒｚ］
各実施例及び比較例で得た多層配線板の外層回路をエッチングにより銅を除去した試験片を作製した。この試験片を２ｍｍ角程度に切断した。キーエンス社製超深度形状測定顕微鏡製品名ＶＫ−８５００を用いて、試験片表面から測定長さ１４９μｍを選択し、倍率２０００倍、分解能０．０５μｍの条件で観察し、１４９μｍ中の十点平均粗さ（Ｒｚ）を算出した。
【００５３】
［外層回路との接着強度］
各実施例及び比較例で得た多層配線板のＬ１回路層（第三の回路層）の一部に幅１０ｍｍ、長さ１００ｍｍの部分を形成し、この一端を回路層／樹脂界面で剥がしてつかみ具でつかみ、垂直方向に引張り速度約５０ｍｍ／分で室温中で引き剥がした時の荷重を測定した。
【００５４】
［絶縁樹脂の冷熱サイクル試験下でのクラック発生率］
内層の回路板に用いた日立化成工業株式会社製ＭＣＬ−Ｅ−６７（基板厚み０．８ｍｍｔ、商品名）の銅箔を完全にエッチングにより溶解、除去した。この片面上に各実施例及び比較例で得たワニスを、厚み５０±５μｍで塗膜成形した。この絶縁樹脂付き基板を実施例と同様に処理し、絶縁樹脂上に外層回路を形成した。そして外層回路が２ｍｍ角に残るパターンを形成するために銅面上にエッチングレジスト（Ｈ−Ｋ４２５、日立化成工業株式会社製、商品名）を１００℃、０．５ｍ／分、圧力０．５ＭＰａ・ｓの条件でラミネートした。その後、露光量８０ｍＪ／ｃｍ^２で外層回路が２ｍｍ角に残るように作製されたフォトマスクを介して露光した。次いで、炭酸ナトリウム１．０％水溶液の現像液を用いて、３０℃、圧力０．１ＭＰａ・ｓ、現像時間６０秒で現像し、さらに水酸化ナトリウム水溶液でレジストを剥離し、乾燥した。そして、塩化第二鉄水溶液で銅をエッチングして外層回路が２ｍｍ角となる耐クラック性評価パターンを作製した。
この試料を、−５５℃〜１２５℃（各１５分）の冷熱サイクル試験を実施し、顕微鏡で外層回路の２ｍｍ角コーナー部に発生しやすい絶縁樹脂中のクラックを観察し、クラックが入るまでのサイクル試験回数で表した。
【００５５】
［不飽和雰囲気下での絶縁信頼性加速試験］
各実施例及び比較例で作製した多層配線板において、絶縁樹脂の層間方向に電圧印加できるように端子部にリード線をはんだ付けで固定した。そして、絶縁樹脂の層間方向の絶縁抵抗を室温中で５０Ｖ、１分印加して測定した。さらに、これを試料とし、１３０℃、８５％ＲＨの不飽和雰囲気下で直流電圧６Ｖを印加しながら所定時間で試料を取り出し、室温中で５０Ｖ、１分印加して測定した時の１０^８Ω以上を示す時間を絶縁信頼性の時間として表した。
【００５６】
［２８８℃はんだ耐熱性］
各実施例及び比較例で作製した多層配線板を２５ｍｍ角に切断し、２８８℃±２℃に調整したはんだ浴に浮かべ、ふくれが発生するまでの時間を調べた。
【００５７】
【表１】

【００５８】
表１から、本発明の絶縁樹脂組成を用いた多層配線板の特性は、実施例１〜４に示したように、難燃性に優れ、また塗膜の引っ張り伸び率が大きいために耐クラック性に良好な結果を示す。さらに、粗化後の表面粗さが小さいながら外層銅との接着強度が良好であり微細配線化に適しており、絶縁信頼性、２８８℃はんだ耐熱性にも優れており環境に配慮した多層配線板を製造することが可能である。一方、本発明の絶縁樹脂組成物を必須に含んでいない比較例１〜２に示す多層配線板は、難燃性や耐クラック性及び粗化後の表面粗さ、絶縁信頼性が悪化する傾向が確認できた。
【００５９】
【発明の効果】
本発明によれば、環境に悪影響を与える可能性があるブロム化合物を一切使用しないで難燃性を有し、鉛フリー化に対応可能な高いはんだ耐熱性と機械的や熱的な応力集中に耐えられるような絶縁樹脂塗膜の高引っ張り伸び率を実現させ、さらに接着強度を維持して粗化後の表面粗さＲｚを１〜３μｍにして微細配線化に対応可能な特性に優れた多層配線板を提供できる。
【図面の簡単な説明】
【図１】（ａ）〜（ｉ）は多層配線板を製造する工程の一例を説明する断面図である。
【符号の説明】
１ａ　　第一の回路層
１ｄ　　第二の回路層
１ｇ　　第三の回路層
２　　　　　　　　　絶縁基板
３　　　　　　　　　回路板
４ｂ、４ｅ　　　　　絶縁材料組成物層
５ｃ、５ｆ　　　　　ビアホール
６ｃ　　　　　第一の絶縁層
６ｆ　　　　　第二の絶縁層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an insulating film with a support, a multilayer wiring board, and a method for manufacturing the same.
[0002]
[Prior art]
To manufacture a multilayer wiring board, a material obtained by impregnating a glass cloth called prepreg with epoxy resin and making it semi-cured on copper foil is laminated on an insulating substrate with an inner layer circuit formed on one or both sides by hot pressing. After integration, a hole called a through hole for interlayer connection is drilled, electroless plating is performed on the inner wall of the through hole and the copper foil surface, and if necessary, electrolytic plating is further performed to achieve the required thickness as a circuit conductor. After that, unnecessary copper is generally removed to manufacture a multilayer wiring board.
By the way, in recent years, the miniaturization, weight reduction, and multifunctionality of electronic devices have been further advanced, and with this, the integration of LSIs and chip components has been advanced, and the form has rapidly changed to multipins and miniaturization. ing. For this reason, in the multilayer wiring board, development of fine wiring has been promoted in order to improve the mounting density of electronic components. As a method of manufacturing a multilayer wiring board that meets these requirements, a build-up type multilayer that uses an insulating resin that does not contain glass cloth as an insulating layer instead of a prepreg and forms wiring layers while connecting only necessary parts with via holes There is a wiring board, and it is becoming mainstream as a method suitable for weight reduction, miniaturization, and miniaturization.
[0003]
In addition, there is an increasing movement to regulate materials that may generate harmful substances during combustion, including electronic components, due to increased environmental awareness. In conventional multilayer wiring boards, bromo compounds that may generate harmful substances during combustion have been used for flame retardancy, but it is expected that their use will be difficult in the near future.
Further, as a solder generally used for connecting an electronic component to a multilayer wiring board, a lead-free solder having no lead is being put into practical use. Since the use temperature of the lead-free solder is higher than that of the conventional eutectic solder by about 20 to 30 ° C., the material must have higher solder heat resistance than before.
[0004]
As described above, items required for a multilayer wiring board are becoming more severe year by year, and especially, an insulating layer having an important role of connecting a substrate and a circuit needs to have higher performance.
However, since the insulating resin layer that does not contain glass cloth for thinning the multilayer wiring board does not contain glass cloth, the mechanical properties of the insulating resin greatly affect the characteristics of the multilayer wiring board. Specifically, when the insulating resin is hard and has a small elongation and a brittle property, the insulating resin is cracked or chipped due to mechanical stress at the time of punching to a product size of the multilayer wiring board, resulting in large conduction or insulation reliability. It will hinder. In addition, the shift of electronic components to surface mount type in order to achieve miniaturization and multifunctionalization of equipment has reduced the distance between the insulating resin and the electronic components, and the thermal stress of the electronic components has concentrated on the insulating resin It's getting easier. In other words, when the insulating resin is hard, has a small elongation and is brittle, the electronic components and the solder or copper that connects it to the multilayer wiring board are likely to crack inside the insulating resin or in the solder or copper due to the thermal stress concentration of the copper. Let me do it.
For this reason, the insulating resin has been required to have a property of having a large deformation, that is, a high tensile elongation, so as to withstand mechanical or thermal stress concentration.
[0005]
[Problems to be solved by the invention]
However, as a method of increasing the tensile elongation, a method of introducing a thermoplastic high molecular weight component is generally employed. However, when a high molecular weight component is introduced, a decrease in the glass transition point is generally unavoidable.
In addition, an insulating resin having high solder heat resistance without using a bromo compound so as not to affect the environment has not been developed at the present stage. The reason is that when a flame retardant is used, the decomposition temperature of the entire insulating resin tends to decrease, and the decomposition at the soldering temperature progresses, so that the solder heat resistance decreases.
In addition, electronic devices have become smaller and more sophisticated, and wiring boards have become finer. For fine wiring, it is necessary to minimize the roughness of the interface between the insulating resin and the circuit conductor from the viewpoint of the etching accuracy of the circuit conductor. For this reason, recently, a copper foil manufacturer has commercialized a low-roughened foil having a surface roughness Rz after roughening of the copper foil from 7 to 8 μm to 3 to 4 μm. However, the roughness of the interface between the insulating resin and the circuit conductor has an important effect on the bonding strength between the insulating resin and the circuit conductor, and the smaller the roughness of the interface, the lower the bonding strength. For this reason, an insulating resin that can exhibit high adhesive strength even with low roughness is required.
[0006]
The present invention is flame-retardant without using any bromo compounds that may adversely affect the environment, withstands high solder heat resistance and mechanical and thermal stress concentration that can respond to lead-free. A semi-cured insulating resin with low roughness after roughening while maintaining the adhesive strength of the coating so that it can achieve a high tensile elongation rate of the coating film of the insulating resin that can be used and can support fine wiring An object of the present invention is to provide an insulating film with a support, a multilayer wiring board using the film as an insulating layer, and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
The present inventors have conducted research to solve such a problem, and as a result, as an insulating layer in a multilayer wiring board, a copolymer of epoxy resin and acrylonitrile butadiene having a biphenyl structure and a novolak structure and a phosphorus-containing phenol resin. Highly solderable that can be used for lead-free by using an insulating resin containing a thermosetting agent and an inorganic filler as an essential component, without using any bromo compound that may adversely affect the environment. Achieves high tensile elongation of the insulating resin coating that can withstand heat resistance and mechanical and thermal stress concentration, and furthermore, surface roughness after roughening so that it can be used for fine wiring of multilayer wiring boards Was found to be in the range of 1 to 3 μm with Rz.
[0008]
That is, (1) the insulating film with a support of the present invention comprises (A) an epoxy resin having a biphenyl structure and a novolak structure, and (B) a mixture of a particulate material of a copolymer of acrylonitrile butadiene and a linear polymer. And (C) a semi-cured film of an insulating resin composition containing a phosphorus-containing phenolic resin, (D) a thermosetting agent, and (E) an inorganic filler is formed on the surface of the support. The gist is an insulating film with a support.
[0009]
(2) The first multilayer wiring board of the present invention is a multilayer wiring board in which an insulating layer and an outer circuit layer are sequentially laminated on one or both sides of a substrate having an inner circuit,
(A) a mixture of (A) an epoxy resin having a biphenyl structure and a novolak structure, (B) a mixture of particles of a copolymer of acrylonitrile butadiene and a linear polymer, (C) a phosphorus-containing phenol resin, and (D) heat. The gist is a multilayer wiring board including an insulating resin layer obtained by curing an insulating resin composition containing a curing agent and (E) an inorganic filler.
[0010]
(3) A second multilayer wiring board of the present invention is a multilayer wiring board in which an insulating layer and an outer circuit layer are sequentially laminated on one or both sides of a substrate having an inner layer circuit, wherein the insulating layer is the above (1). The gist of the present invention is a multilayer wiring board including an insulating resin layer obtained by curing a film of the insulating film with a support.
[0011]
(4) In the multilayer wiring board according to the above (2) or (3), the insulating resin layer preferably has a tensile elongation of 4% or more.
(5) In the multilayer wiring board according to any one of (2) to (4), the surface roughness of the interface between the insulating resin layer and the outer circuit layer is preferably 1 to 3 in Rz.
(6) In the multilayer wiring board according to any one of (2) to (5), the epoxy resin having the biphenyl structure and the novolak structure in the ratio (A) is 35 to 60 in the total solid content of the insulating resin composition. % By weight, and the solid content of the mixture of (A) the epoxy resin and (B) the mixture of the particulate material of the copolymer of acrylonitrile butadiene and the linear polymer is 80/20 to 95/5 by weight. It is preferable that
(7) In the multilayer wiring board according to any one of (2) to (6), (C) the phosphorus content in the phosphorus-containing phenolic resin is (E) the solid content of the insulating resin composition excluding the inorganic filler. Is preferably 0.7 to 3.0% by weight.
[0012]
Further, the method for manufacturing a multilayer wiring board of the present invention is (8) a method for manufacturing a multilayer wiring board according to any one of the above (2) to (7),
(A) an epoxy resin having a biphenyl structure and a novolak structure, (B) a mixture of particles of a copolymer of acrylonitrile butadiene and a linear polymer, (C) a phosphorus-containing phenol resin, and (D) a thermosetting agent. E) a step of laminating a layer containing an insulating resin composition layer containing an inorganic filler on a substrate having an internal circuit (a);
A step of curing the insulating resin composition to obtain an insulating resin layer (b),
Forming an outer circuit layer on the surface of the insulating resin layer (c),
The gist is a method for manufacturing a multilayer wiring board including:
[0013]
(9) The method for manufacturing a multilayer wiring board according to (8), wherein the step (b) includes a step of roughening the surface of the insulating resin layer with an oxidizing roughening liquid after obtaining the insulating resin layer. Is preferred.
(10) In the method for manufacturing a multilayer wiring board according to the above (8) or (9), in the step (c), it is preferable that the outer layer circuit is formed by copper plating.
(11) In the method for producing a multilayer wiring board according to any one of the above (8) to (10), in the step (a), a varnish of an insulating resin composition is applied to a support and dried to form an insulation with a support. It is preferable to form a layer and laminate this insulating film with a support on a substrate having an inner layer circuit.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the composition of the insulating resin composition and the cured insulating resin thereof according to the present invention will be described.
(A) An epoxy resin having a biphenyl structure and a novolak structure is an epoxy resin having a novolak structure containing an aromatic ring of a biphenyl derivative in a molecule, and is an NC-3000S (trade name) manufactured by Nippon Kayaku Co., Ltd. And NC-3000S-H (trade name) can be used.
[0015]
The amount of the epoxy resin having the biphenyl structure and the novolak structure is preferably 35 to 60% by weight based on the total solid content of the insulating resin composition excluding the solvent, and (A) the biphenyl structure. The solid content ratio (weight ratio, hereinafter the same) of the epoxy resin having the structure and the novolak structure and the mixture of the particulate material (B) of the acrylonitrile butadiene copolymer and the linear polymer is 80/20 to 95/5. It is preferred that If the amount of the component (A) is less than 35% by weight, the solder heat resistance tends to decrease, and if it exceeds 60% by weight, the adhesive strength to the circuit conductor tends to decrease. In addition, in the above-mentioned solid content ratio of the component (A) and the component (B), when the component (A) is less than 80/20, the solder heat resistance is deteriorated, and conversely, the component (B) is less than 95/5. Increases, the tensile elongation of the coating film tends to decrease.
[0016]
(B) The mixture of the particulate material of the copolymer of acrylonitrile butadiene and the linear polymer includes, as the copolymer of acrylonitrile butadiene, NBR obtained by copolymerizing acrylonitrile and butadiene, such as acrylonitrile, butadiene, and acrylic acid. Can also be used. These are two types of mixtures of linear NBR obtained without cross-linking at the stage of copolymerization and partially cross-linked particulate NBR. The mixture ratio of this mixture is good in all properties in the vicinity of the same amount in terms of the solid content ratio. For example, in the case of the mixture obtained by copolymerizing the acrylonitrile, butadiene and carboxylic acid, the linear NBR and the particulate NBR are mixed. A compounding ratio of 3/7 to 8/2 can be suitably used. In this case, if the ratio of linear NBR is less than 3/7, the insulating resin is applied and the coating film after drying becomes uneven, and if it exceeds 8/2, the roughness after roughening increases. It tends to be unsuitable for finely roughened shapes.
[0017]
(C) The phosphorus-containing phenol resin is obtained by reacting a bifunctional phenol resin with an organic phosphorus compound, and for example, HCA-HQ (trade name) manufactured by Sanko Co., Ltd. can be used. It is preferable that the phosphorus content be in the range of 0.7 to 3% by weight in the solid content of the insulating resin composition excluding the inorganic filler in order to exhibit flame retardancy. When the phosphorus content is less than 0.7%, the flame retardancy is insufficient to be exhibited, and when the phosphorus content is more than 3%, the solder heat resistance decreases.
[0018]
(D) The thermosetting agent is used for accelerating the reaction between the epoxy group in the epoxy resin having the biphenyl structure and the novolak structure and the phosphorus-containing phenol resin. As the thermosetting agent, various phenol resins, acid anhydrides, amines, hydrazites and the like can be used. As phenolic resins, novolak-type phenolic resins, resol-type phenolic resins, etc. can be used.As acid anhydrides, phthalic anhydride, benzophenonetetracarboxylic dianhydride, methylhymic acid, etc. can be used, and amines can be used. Dicyandiamide, diaminodiphenylmethane, guanylurea and the like. Dicyandiamide is preferable from the viewpoint of adhesiveness to the circuit conductor, and it is more preferable to use dicyandiamide and novolak phenol in consideration of heat resistance and insulation.
These thermosetting agents are preferably used in an amount of 0.5 to 1.5 equivalents to the epoxy group. When the amount of the thermosetting agent is less than 0.5 equivalent relative to the epoxy group, the adhesiveness to the outer layer copper is reduced, and when the amount exceeds 1.5 equivalents, Tg and insulation may be reduced.
[0019]
In addition to the thermosetting agent, a reaction accelerator can be used if necessary. As the reaction accelerator, various imidazoles and BF ₃ amine complexes which are latent thermosetting agents can be used. More preferably, 2-phenylimidazole or 2-ethyl-4-methylimidazole is preferred from the viewpoints of storage stability of the insulating resin composition, handleability of the B-stage (semi-cured) insulating resin composition, and solder heat resistance. Preferably, the compounding amount is optimally 0.2 to 0.6% by weight based on the compounding amount of the epoxy resin having a biphenyl structure and a novolak structure. If the amount is less than 0.2% by weight, the solder heat resistance is not sufficient, and if the amount exceeds 0.6% by weight, the storage stability of the insulating resin composition and the handleability of the B-staged insulating resin composition deteriorate. .
[0020]
(E) As the inorganic filler, for example, one selected from silica, fused silica, talc, alumina, aluminum hydroxide, barium sulfate, calcium hydroxide, aerosil, and calcium carbonate can be used, and these can be used alone or in combination. You may use it. From the viewpoint of flame retardancy and low thermal expansion, it is preferable to use aluminum hydroxide and silica alone or in combination. Further, the compounding amount is preferably 5 to 30 vol% in the solid content of the whole insulating resin composition excluding the solvent. More preferably, it is 10 to 20% by volume, and if it is less than 5% by volume, the adhesion to the outer layer circuit conductor is inferior. If it exceeds 30% by volume, the surface roughness after roughening may be large, resulting in a fine roughened shape. Become unsuitable.
These inorganic fillers may be treated with a coupling agent for the purpose of enhancing dispersibility, or may be dispersed by a known kneading method such as a kneader, a ball mill, a bead mill, or a three-roll mill.
[0021]
The insulating resin composition of the present invention is obtained by blending the above essential components (A) to (E), as well as a thixotropy-imparting agent, a surfactant, a coupling agent, and the like used in ordinary resin compositions. Of various additives can be appropriately compounded. After these are sufficiently stirred, the mixture is allowed to stand until bubbles disappear, thereby obtaining an insulating resin composition.
[0022]
It is preferable from the viewpoint of workability that the insulating resin composition of the present invention is mixed and diluted or dispersed in a solvent to form a varnish. As this solvent, methyl ethyl ketone, xylene, toluene, acetone, ethylene glycol monoethyl ether, cyclohexanone, ethyl ethoxypropionate, N, N-dimethylformamide, N, N-dimethylacetamide and the like can be used. These solvents may be used alone or as a mixture. The ratio of the solvent to the resin composition may be a conventionally used ratio, and the amount of the solvent is adjusted according to the equipment for forming a coating film of the insulating resin composition.
When applying the insulating resin composition to a carrier film or copper foil with a comma coater, it is preferable to adjust the amount of the solvent used so that the solid content of the resin composition excluding the solvent is 30 to 60% by weight in the varnish. .
[0023]
The insulating film with a support of the present invention is characterized in that the above-mentioned semi-cured film of the insulating resin composition is formed on the surface of the support.
In order to obtain an insulating film with a support, for example, a method in which a varnish of an insulating resin composition is prepared as described above, the varnish is applied on a support, and dried. When a varnish is applied on a support, a comma coater, a bar coater, a kiss coater, a roll coater, or the like can be used, and is appropriately used depending on the thickness of the insulating film. The thickness of the coating, drying conditions after the coating, and the like are not particularly limited because they are appropriately selected according to the purpose of use, but generally, it is preferable that the solvent used in the varnish is volatilized by 80% by weight or more.
Examples of the support on which the insulating film is formed on the surface include a plastic film such as PET and a metal foil. When the support is peeled off after the insulating film is cured, a releasable plastic film is preferable.
[0024]
In the multilayer wiring board of the present invention, an insulating layer and an outer circuit layer are sequentially laminated on one or both sides of a substrate having an inner circuit. The insulating layer includes an insulating resin layer obtained by curing the insulating resin composition. The insulating resin composition is cured by heat history during the production of the multilayer wiring board.
Further, the insulating resin layer may be an insulating resin layer obtained by curing the insulating film with a support of the present invention.
[0025]
The tensile elongation of the insulating resin layer in the present invention is preferably 4% or more. The upper limit is not particularly limited as long as other characteristics are not affected. If it is less than 4%, deformation that can withstand mechanical or thermal stress concentration is reduced, so that the thermal stress concentration of the electronic component and solder or copper that connects it to the multilayer wiring board causes the thermal stress concentration in the insulating resin. Cracks tend to occur.
In the present invention, the surface roughness of the insulating resin layer after the roughening treatment is preferably such that Rz is in the range of 1 to 3.
Incidentally, the tensile elongation rate in the present invention is a rate at which the sample is stretched when a film-shaped sample is pulled at a constant speed by a tensile tester, that is, for example, a sample having a thickness of 50 μm is cut into a 10 mm × 100 mm strip. And shows the rate at which the sample stretches before the sample is cut when 10 mm at both ends in the longitudinal direction are fixed and pulled at a speed of 5 mm / min.
Rz is the ten-point average roughness of the surface roughness, that is, the average value of the absolute values from the average line of the highest to fifth peaks in the extracted portion of the object surface, and the fifth value from the lowest. Is a parameter indicating the sum of the average value of the absolute value from the average line of the valley bottom up to (JIS B0601). In the present invention, Rz (μm) was obtained from the extracted portion of 149 μm.
[0026]
The multilayer wiring board of the present invention can be manufactured by the following method for manufacturing a multilayer wiring board of the present invention.
With reference to FIG. 1, a process of manufacturing a multilayer wiring board using the above-mentioned insulating resin composition will be described. 1A to 1I are cross-sectional views illustrating an example of a process for manufacturing a multilayer wiring board.
First, a circuit board 3 having a first circuit layer 1a formed on an insulating substrate 2 is prepared (see FIG. 1A).
The circuit board is, for example, an inner-layer board having a first circuit layer (inner-layer wiring) formed on the surface. As the inner-layer board, a known laminated board used in a normal wiring board, for example, glass cloth-epoxy Resin, paper-phenol resin, paper-epoxy resin, glass cloth / glass paper-epoxy resin and the like can be used without any particular limitation. Further, a BT substrate impregnated with a bismaleimide-triazine resin, a polyimide film substrate using a polyimide film as a base material, or the like can also be used.
[0027]
There is no particular limitation on the method for forming the circuit layer 1a, and a subtractive method in which an unnecessary portion of the copper foil is removed by etching using a copper-clad laminate in which a copper foil and the insulating substrate are bonded, A known method of manufacturing a wiring board, such as an additive method of forming a circuit by electroless plating at a necessary portion of an insulating substrate, can be used.
[0028]
FIG. 1A shows an example in which the circuit layer 1a is formed on one surface of the insulating substrate 2, but the circuit layer 1a may be formed on both surfaces of the insulating substrate 2 using a double-sided copper-clad laminate.
[0029]
Next, if necessary, the surface of the circuit layer 1a is surface-treated to a state suitable for adhesiveness. This method is also not particularly limited. For example, copper oxide needle-like crystals are formed on the surface of the circuit layer 1a with an aqueous solution of sodium hypochlorite, and the formed copper oxide needle-like crystals are converted into a dimethylamine borane aqueous solution. A known production method such as immersion and reduction can be used.
[0030]
(A) Then, an insulating resin composition layer 4b is formed on one or both sides of the circuit board 3 having the circuit layer 1a (see FIG. 1B). In FIG. 1B, the circuit layer 1a is formed on one side of the circuit board 3, but may be formed on both sides. In this case, the insulating resin composition layer 4b can be formed on both sides of the circuit board 3. . Further, there is no particular limitation on this forming method. For example, there is a method of laminating the insulating film with a support of the present invention on the circuit board 3. Further, there is a method in which a layer is formed by directly coating one or both sides of the circuit board 3 having the circuit layer 1a using a curtain coat or a roll coater.
[0031]
When the varnish is applied on the circuit board, a general application method such as bar coating, spin coating, and screen printing can be used. In any case, the coating thickness and the drying conditions after coating are not particularly limited, but it is preferable that the solvent used in the varnish is volatilized by 80% by weight or more.
When an insulating film with a support is used, examples of the support on which the varnish is applied include a plastic film such as PET and a metal foil. When the support is peeled off after the varnish is cured, a releasable plastic film or the like is used. Is preferred. When the support is a metal foil such as a copper foil, it can be used as a second circuit layer described later without peeling. The insulating film with a support is laminated on the circuit board 3 by using a laminating method or a press device with the insulating resin composition layer facing the surface of the circuit board in contact with the circuit layer.
[0032]
(B) Thereafter, the insulating resin composition layer is heated and cured to form the first insulating layer 6c which is an insulating resin layer (see FIG. 1 (c)). The curing temperature is determined by a subsequent plating treatment or copper annealing. The process is performed at a temperature and time in consideration of processing and the like. In other words, if the curing is advanced too much, the adhesiveness to copper is reduced during the subsequent plating process, or, if the curing is insufficient, a phenomenon such as being eroded by the alkaline processing solution during the plating process and being dissolved in the plating solution occurs. . In consideration of these points, it is desirable to cure by applying a heat treatment at 150 to 190 ° C. for 30 to 90 minutes.
When the insulating film with a support is used, the pressure laminating step and the heat curing step may be performed simultaneously or separately. The pressure laminating condition may be such that the unevenness of the circuit layer 1a is embedded in the semi-cured insulating resin composition, and is usually preferably 0.5 to 20 MPa.
[0033]
Further, a via hole 5c may be formed in the first insulating layer 6c for interlayer connection between the first circuit layer 1a, which is the inner circuit, and the outer circuit [see FIG. 1 (c)]. There is no particular limitation on the method of forming the via hole, and a laser method, a sand blast method, or the like can be used.
[0034]
(C) Next, the second circuit layer 1d is formed by performing the following circuit processing, and further, an interlayer connection between the first circuit layer 1a and the second circuit layer 1d is formed [FIG. (D)].
First, when the second circuit layer 1d, which is the outer circuit, is formed on the first insulating layer 6c by plating, it is preferable to roughen the first insulating layer 6c. As the roughening solution, an oxidizing roughening solution such as a roughening solution of chromium / sulfuric acid, a roughening solution of alkali permanganate, a roughening solution of sodium fluoride / chromium / sulfuric acid, or a roughening solution of borofluoric acid can be used. As the roughening treatment, for example, first, an aqueous solution of diethylene glycol monobutyl ether and NaOH is heated to 70 ° C. as a swelling liquid, and the first insulating layer 6c is immersed for 5 minutes. Next, as a roughening solution, an aqueous solution of KMnO and NaOH is heated to 80 ° C. and immersed for 10 minutes. Subsequently, neutralization is performed by immersion in a neutralizing solution, for example, an aqueous hydrochloric acid solution of stannous chloride (SnCl ₂ ) at room temperature for 5 minutes.
[0035]
After the roughening treatment, a plating catalyst application treatment for attaching palladium is performed. The plating catalyst treatment is performed by dipping in a palladium chloride-based plating catalyst solution.
Next, it is immersed in an electroless plating solution to cover the entire surface of the first insulating layer 6c (including the inner surface of the via hole when a via hole is formed) with a thickness of 0.3 to 1.5 μm. ) Is precipitated. If necessary, electroplating is further performed to a required thickness. As the electroless plating solution used for the electroless plating, a known electroless plating solution can be used, and there is no particular limitation. Also, the electroplating can be performed by a known method, and there is no particular limitation. These platings are preferably copper platings.
Further, unnecessary portions can be removed by etching to form the second circuit layer 1d and the interlayer connection between the first circuit layer 1a and the second circuit layer 1d.
[0036]
When an insulating film with a copper foil is used for forming the insulating resin composition layer, the outer layer circuit (second circuit layer 1d) is formed by an etching method. The method using this etching method is not particularly limited, and a pattern plating method using an ultrathin copper foil having a thickness of about 3 μm can also be used. The interlayer connection using the insulating film with copper foil can be formed by plating or the like after providing a via hole by a method such as a laser method.
In addition, as a method for forming the second circuit layer 1d, a catalyst for electroless plating is applied to the surface of the roughened insulating layer to deposit electroless plated copper on the entire surface. In addition to the method of forming the circuit conductor to the required thickness by electroplating and removing unnecessary portions by etching, only the necessary portions are formed by forming a plating resist using an insulating layer containing a plating catalyst. A method of forming a circuit by electroless plating, a method of roughening an insulating layer not containing a plating catalyst, forming a plating resist after applying a plating catalyst, and forming a circuit by electroless plating only at a necessary portion, and the like can be used. it can.
[0037]
Furthermore, the surface treatment of the second circuit layer 1d is performed in the same manner as the surface treatment of the first circuit layer 1a, and the insulating resin composition layer 4e is formed in the same manner as the formation of the insulating resin composition layer 4b [ FIG. 1 (e)]. Next, the insulating resin composition layer 4e is cured to form a second insulating layer 6f, and a via hole 5f is formed (see FIG. 1 (f)). Further, similarly, a third circuit layer 1g is formed [see FIG. 1 (g)].
Hereinafter, by repeating the same steps, a multilayer wiring board having a large number of layers can be manufactured.
[0038]
【Example】
Next, the present invention will be described with reference to examples, but the scope of the present invention is not limited to these examples.
(Example 1)
(1) Glass cloth substrate epoxy resin double-sided copper-clad laminate [MCL-E-67 (trade name) manufactured by Hitachi Chemical Co., Ltd. having a copper foil thickness of 18 μm, a substrate thickness of 0.8 mmt, and a double-sided roughened foil on both sides )] Was etched on one side to produce a circuit board having a circuit layer on one side (hereinafter, referred to as a first circuit layer).
[0039]
(2) A varnish of the insulating resin composition having the following composition was prepared. At this time, the equivalent of the thermosetting agent to the epoxy was set to 1.0 equivalent. A varnish of this insulating resin composition was applied on a PET film and dried at 100 ° C. for 10 minutes to prepare a roll of an insulating film with a support having a thickness of 50 ± 3 μm. Further, the insulating film with the support and the circuit board are set such that the insulating resin composition layer is in contact with the first circuit layer of the circuit board, and the batch type vacuum pressure laminator MVLP-500 (manufactured by Meiki Co., Ltd.) (Trade name).
[0040]
[composition]
(A) Epoxy resin having biphenyl structure and novolak structure: NC3000S-H
82 parts by weight (trade name, manufactured by Nippon Kayaku Co., Ltd.) (B) PNR-1H (trade name, manufactured by JSR Corporation) of carboxylic acid-modified acrylonitrile butadiene rubber (linear NBR) and XER- of particulate NBR 91 (JSR Corporation, trade name) mixed at a solid content ratio of 1: 1 12 parts by weight · (C) phosphorus-containing phenol resin: HCA-HQ
(Manufactured by Sanko Co., Ltd., 28 parts by weight) (D) Thermosetting agent: dicyandiamide (manufactured by Nippon Carbide Co., Ltd.)
1 part by weight ・ (D) thermosetting agent: novolak phenol resin (HP-850)
(Manufactured by Hitachi Chemical Co., Ltd., trade name) 5 parts by weight ・ Reaction accelerator: 2-phenylimidazole (manufactured by Shikoku Chemicals Co., Ltd., trade name: 2PZ) 0.3 part by weight ・ (E) inorganic filler: aluminum hydroxide (Heidilite H-42M)
(Manufactured by Showa Denko KK, trade name) 22 parts by weight ・ (E) Inorganic filler: spherical silica (Admafine SO-25R)
(Manufactured by Admatechs Co., Ltd., trade name) 20 parts by weight, solvent: methyl ethyl ketone 40 parts by weight, solvent: dimethylformamide 26 parts by weight
(3) Next, after peeling off the PET film, the insulating resin composition layer was cured under a curing condition of 180 ° C. for 60 minutes to obtain a first insulating layer.
(4) A via hole for interlayer connection was formed in the first insulating layer using a CO ₂ laser beam machine (LCO-1B21 type, manufactured by Hitachi Via Mechanics), beam diameter 80 μm, frequency 500 Hz, pulse width 5 μsec, number of shots 7 It was manufactured by processing under the conditions.
[0042]
(5) In order to chemically roughen the first insulating layer, an aqueous solution of diethylene glycol monobutyl ether: 200 ml / L and NaOH: 5 g / L was prepared as a swelling solution, heated to 70 ° C., and immersed for 5 minutes. did. Next, as a roughening solution, an aqueous solution of KMnO ₄ : 60 g / L and NaOH: 40 g / L was prepared, heated to 80 ° C., and immersed for 10 minutes. Subsequently, neutralization was performed by immersion in an aqueous solution of a neutralizing solution (SnCl ₂ : 30 g / L, HCl: 300 ml / L) at room temperature for 5 minutes.
[0043]
(6) In order to form a second circuit layer on the surface of the first insulating layer, first, HS-202B (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is an electroless plating catalyst containing PdCl ₂ , It was immersed at room temperature for 10 minutes, washed with water, immersed in a plating solution CUST-201 (trade name, manufactured by Hitachi Chemical Co., Ltd.) for electroless copper plating at room temperature for 15 minutes, and further subjected to copper sulfate electrolytic plating. . Thereafter, annealing was performed at 180 ° C. for 30 minutes to form a conductor layer having a thickness of 20 μm on the surface of the first insulating layer and in the via hole.
Next, in order to remove unnecessary portions of the plated conductor by etching, first, an oxide film on the copper surface is removed by buffling with # 600, an etching resist is formed, then etching is performed, and then the etching resist is removed. A second circuit including via holes connected to the first circuit layer was formed.
[0044]
(7) Further, in order to form a multilayer structure, the surface of the second circuit conductor was subjected to an aqueous solution of sodium chlorite: 50 g / l, NaOH: 20 g / l, and trisodium phosphate: 10 g / l at 85 ° C. for 20 minutes. It was immersed, washed with water, and dried at 80 ° C. for 20 minutes to form copper oxide irregularities on the surface of the second circuit conductor.
(8) The steps (2) to (7) were repeated to produce a three-layer multilayer wiring board.
[0045]
(Example 2)
In Example 1, spherical silica (Admafine SO-25R) was used alone without using aluminum hydroxide as the inorganic filler, and the blending amount was 32 parts by weight. Others were performed similarly to Example 1.
[0046]
(Example 3)
In Example 1, instead of producing an insulating film with a support and laminating the film on the first circuit layer, a varnish of the insulating resin composition was directly applied to the surface of the circuit board having the first circuit layer. It was applied with a roll coater and dried at 110 ° C. for 10 minutes to form an insulating resin composition layer having a thickness of 50 ± 3 μm. Other than that, it carried out similarly to Example 1.
[0047]
(Example 4)
In Example 1, carboxylic acid-modified acrylonitrile butadiene rubber (linear NBR) PNR-1H (JSR Corporation, trade name) was replaced with acrylonitrile butadiene rubber (linear NBR) N-220S (JSR stock) with the same blending amount. (Company, product name). Others were performed similarly to Example 1.
[0048]
(Comparative Example 1)
In Example 1, the epoxy resin was replaced with YDCN-702 (trade name of Toto Kasei Co., Ltd.) of ortho-cresol novolak resin with the same blending amount of 82 parts by weight, and the equivalent amount of the thermosetting agent was made similar to that of Example 1. Therefore, the blending amount of dicyandiamide was 2.9 parts by weight, and the blending amount of novolak phenol resin was 7 parts by weight. Others were performed similarly to Example 1.
[0049]
(Comparative Example 2)
In Example 1, carboxylic acid-modified acrylonitrile-butadiene rubber (linear NBR) PNR-1H was used in an amount of 12 parts by weight without using XER-91 (trade name) of particulate NBR. Other than that, it carried out similarly to Example 1.
[0050]
Regarding the varnish and multilayer wiring board of the resin composition prepared as described above, (1) flame retardancy, (2) tensile elongation of the insulating resin coating film, (3) surface roughness of the insulating resin after roughening. , (4) Adhesive strength with outer layer circuit, (5) Crack generation rate under thermal cycle test of insulating resin, (6) Accelerated insulation reliability test under unsaturated atmosphere, (7) 288 ° C solder heat resistance The test was performed. Table 1 shows the results.
[Flame retardance]
In each of the Examples and Comparative Examples, used as the inner layer circuit board, the glass cloth base epoxy resin double-sided copper-clad laminate was etched to produce a board in which the copper foil was completely peeled off, and on both sides of this board, The varnish was applied so that the thickness of the insulating resin on one side was 150 μm to form an insulating resin composition layer. Then, by heating after 180 ° C. for 1 hour, a flame-retardant test piece was prepared. The test method was tested according to the UL-94 method.
[0051]
[Tensile elongation of coating film]
The varnish in each of the examples and comparative examples was applied to a copper foil, and cured by applying a heat treatment at 180 ° C. for 60 minutes in the same manner as in the preparation of the wiring board. Then, an insulating resin coating film cured by removing the copper by etching was obtained. This insulating resin coating film is cut into a thickness of 50 μm, a width of 10 mm, and a length of 100 mm, and is subjected to an autograph tensile test (distance between chucks of 50 mm) at a pulling speed of about 5 mm / min until the insulating resin coating film is pulled and broken. The tensile elongation was determined.
[0052]
[Surface roughness after roughening: Rz]
Test pieces were prepared by etching the outer layer circuit of the multilayer wiring board obtained in each of the examples and comparative examples to remove copper by etching. This test piece was cut into approximately 2 mm square. Using a Keyence's ultra-depth shape measuring microscope product name VK-8500, a measurement length of 149 μm was selected from the surface of the test piece, observed under the conditions of 2000 times magnification and 0.05 μm resolution, and a 10-point average roughness in 149 μm (Rz) was calculated.
[0053]
[Adhesive strength to outer layer circuit]
A portion having a width of 10 mm and a length of 100 mm was formed on a part of the L1 circuit layer (third circuit layer) of the multilayer wiring board obtained in each of the examples and the comparative examples, and one end was peeled off at the circuit layer / resin interface. The load was measured when it was gripped with a gripper and peeled off at room temperature at a tensile speed of about 50 mm / min.
[0054]
[Crack generation rate of insulating resin under thermal cycle test]
The copper foil of MCL-E-67 (substrate thickness 0.8 mmt, trade name) manufactured by Hitachi Chemical Co., Ltd. used for the inner layer circuit board was completely dissolved and removed by etching. The varnish obtained in each of Examples and Comparative Examples was formed into a coating film on one surface with a thickness of 50 ± 5 μm. This substrate with an insulating resin was treated in the same manner as in the example, and an outer layer circuit was formed on the insulating resin. Then, an etching resist (H-K425, manufactured by Hitachi Chemical Co., Ltd., trade name) is applied on the copper surface at 100 ° C., 0.5 m / min, and pressure 0.5 MPa. Lamination was performed under the conditions of s. Thereafter, exposure was performed at a light exposure of 80 mJ / cm ² through a photomask manufactured so that the outer layer circuit remained in a 2 mm square. Next, using a developing solution of a 1.0% aqueous solution of sodium carbonate, development was performed at 30 ° C. under a pressure of 0.1 MPa · s for a developing time of 60 seconds. Then, copper was etched with an aqueous ferric chloride solution to prepare a crack resistance evaluation pattern having an outer layer circuit of 2 mm square.
This sample was subjected to a cooling / heating cycle test at −55 ° C. to 125 ° C. (each 15 minutes), and a crack in the insulating resin which was likely to be generated at a corner of a 2 mm square of the outer layer circuit was observed with a microscope. It was represented by the number of cycle tests.
[0055]
[Accelerated insulation reliability test in unsaturated atmosphere]
In the multilayer wiring boards manufactured in each of the examples and the comparative examples, lead wires were fixed to the terminal portions by soldering so that a voltage could be applied in the interlayer direction of the insulating resin. Then, the insulation resistance in the interlayer direction of the insulation resin was measured by applying 50 V for 1 minute at room temperature. Further, using this as a sample, the sample was taken out for a predetermined time while applying a DC voltage of 6 V in an unsaturated atmosphere of 130 ° C. and 85% RH, and was applied at 50 V for 1 minute at room temperature to measure 10 ⁸ Ω. The time indicated above was expressed as insulation reliability time.
[0056]
[288 ° C solder heat resistance]
The multilayer wiring boards prepared in the respective Examples and Comparative Examples were cut into 25 mm squares, floated on a solder bath adjusted to 288 ° C. ± 2 ° C., and the time required until blistering occurred was examined.
[0057]
[Table 1]

[0058]
Table 1 shows that the characteristics of the multilayer wiring board using the insulating resin composition of the present invention are excellent in flame retardancy and high in crack elongation due to the large tensile elongation of the coating film as shown in Examples 1 to 4. The results show good results. Furthermore, although the surface roughness after roughening is small, the adhesive strength to the outer layer copper is good and suitable for fine wiring, insulation reliability, excellent 288 ° C solder heat resistance, and environmentally friendly multilayer wiring It is possible to manufacture boards. On the other hand, the multilayer wiring boards shown in Comparative Examples 1 and 2, which do not essentially contain the insulating resin composition of the present invention, have a tendency to deteriorate in flame retardancy, crack resistance, surface roughness after roughening, and insulation reliability. Was confirmed.
[0059]
【The invention's effect】
According to the present invention, it has flame retardancy without using any bromo compound that may adversely affect the environment, and has high solder heat resistance and mechanical and thermal stress concentration that can respond to lead-free. A multi-layer excellent in properties capable of coping with fine wiring by realizing a high tensile elongation rate of the insulating resin coating film that can withstand, maintaining the adhesive strength, and setting the surface roughness Rz after roughening to 1 to 3 μm. A wiring board can be provided.
[Brief description of the drawings]
FIGS. 1A to 1I are cross-sectional views illustrating an example of a process for manufacturing a multilayer wiring board.
[Explanation of symbols]
1a first circuit layer 1d second circuit layer 1g third circuit layer 2 insulating substrate 3 circuit board 4b, 4e insulating material composition layer 5c, 5f via hole 6c first insulating layer 6f second insulating layer

Claims

(A) an epoxy resin having a biphenyl structure and a novolak structure, (B) a mixture of particles of a copolymer of acrylonitrile butadiene and a linear polymer, (C) a phosphorus-containing phenol resin, and (D) thermosetting. An insulating film with a support, characterized in that a semi-cured film of an insulating resin composition containing an agent and (E) an inorganic filler is formed on the surface of the support.

A multilayer wiring board in which an insulating layer and an outer circuit layer are sequentially laminated on one or both surfaces of a substrate having an inner circuit, wherein the insulating layer has
(A) an epoxy resin having a biphenyl structure and a novolak structure, (B) a mixture of particles of a copolymer of acrylonitrile butadiene and a linear polymer, (C) a phosphorus-containing phenol resin, and (D) thermosetting. A multilayer wiring board comprising an insulating resin layer obtained by curing an insulating resin composition containing an agent and (E) an inorganic filler.

A multilayer wiring board in which an insulating layer and an outer circuit layer are sequentially laminated on one or both surfaces of a substrate having an inner circuit,
A multilayer wiring board, wherein the insulating layer includes an insulating resin layer obtained by curing the insulating film with a support according to claim 1.

4. The multilayer wiring board according to claim 2, wherein the tensile extension of the insulating resin layer is 4% or more.

The multilayer wiring board according to any one of claims 2 to 4, wherein the surface roughness of the interface between the insulating resin layer and the outer circuit layer is 1 to 3 in Rz.

(A) the epoxy resin having a biphenyl structure and a novolak structure is 35 to 60% by weight based on the total solid content of the insulating resin composition, and (A) the epoxy resin and (B) acrylonitrile butadiene are used. The multilayer wiring board according to any one of claims 2 to 5, wherein the compounding ratio of the solid content of the particulate matter of the copolymer and the mixture of the linear polymer is 80/20 to 95/5 by weight.

(C) The phosphorus content in the phosphorus-containing phenolic resin is 0.7 to 3.0% by weight in the solid content of the insulating resin composition excluding the inorganic filler (E). Multilayer wiring board.

A method for producing a multilayer wiring board according to any one of claims 2 to 7,
(A) an epoxy resin having a biphenyl structure and a novolak structure;
(B) an insulating resin composition containing a mixture of a particulate material of a copolymer of acrylonitrile butadiene and a linear polymer, (C) a phosphorus-containing phenol resin, (D) a thermosetting agent, and (E) an inorganic filler. Laminating a layer including a layer on a substrate having an inner layer circuit (a),
A step of curing the insulating resin composition to obtain an insulating resin layer (b),
Forming an outer circuit layer on the surface of the insulating resin layer (c),
A method for manufacturing a multilayer wiring board, comprising:

9. The method for manufacturing a multilayer wiring board according to claim 8, wherein the step (b) includes a step of roughening the surface of the insulating resin layer with an oxidizing roughening liquid after obtaining the insulating resin layer.

10. The method for manufacturing a multilayer wiring board according to claim 8, wherein in the step (c), the outer layer circuit is formed by copper plating.

In the step (a), a varnish of an insulating resin composition is applied to a support and dried to produce an insulating film with a support, and the insulating film with a support is laminated on a substrate having an inner layer circuit. 11. The method for producing a multilayer wiring board according to any one of items 10 to 10.