JP2004168942A - Method for producing prepreg having adhesive layer and prepreg having adhesive layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a prepreg having an adhesive layer, capable of firmly bonding a conductor layer to the prepreg even in the case of using a conductor layer having a smooth surface without roughening treatment and exhibiting high heat-resistance. <P>SOLUTION: A 2nd curable resin is laminated as an adhesive layer on a prepreg composed of a 1st curable resin of B-stage containing reinforcing fibers. The lamination of the 2nd curable resin on the prepreg is carried out while heating the prepreg and the 2nd curable resin taking care of not to complete the curing of the resin. <P>COPYRIGHT: (C)2004,JPO

Description

【化５】

［式中、Ｘは、下記一般式（３ａ）又は（３ｂ）で表される官能基であり、Ｒ^１はアルキル基、フェニル基又は置換フェニル基、Ｒ^２はアルキレン基、フェニレン基又は置換フェニレン基、ｎは１〜１５の整数を示す。
【化６】

但し、Ｙは、炭素数１〜３の脂肪族炭化水素基、炭素数１〜３のハロゲン化脂肪族炭化水素基、スルホニル基、エーテル基、カルボニル基又は単結合であり、複数存在するＲ^１及びＲ^２のそれぞれは同一であっても異なっていてもよい。］
【００１８】
かかる反応により得られるポリアミドイミドを第２の硬化性樹脂に含有させることにより、金属張積層板における接着性を更に向上させることができる。
【００１９】
上記アミド反応性化合物は、２つ以上のエポキシ基を有する多官能エポキシ化合物であることが好ましく、また、積層する際の加熱は８０〜１５０℃で実施することが好ましい。これにより、得られる金属張積層板の接着性及び耐熱性を更に向上させることができる。
【００２０】
本発明はまた、上記の製造方法により得られた接着剤層付きプリプレグを提供する。
【００２１】
【発明の実施の形態】
以下、本発明の好適な実施形態について説明する。
【００２２】
まず、プリプレグについて説明する。
プリプレグは、強化繊維に第１の硬化性樹脂を含浸させた後に、かかる第１の硬化性樹脂を半硬化状態（Ｂステージ）にすることにより得ることができる。第１の硬化性樹脂としてはエポキシ樹脂、ポリイミド樹脂、フェノール樹脂等の熱硬化性樹脂を用いることが好ましい。強化繊維としては、Ｅガラス、Ｄガラス、Ｓガラス、Ｑガラス等からなるガラス繊維、ポリイミド、ポリエステル、テトラフルオロエチレン等からなる有機繊維、及びこれらを混合した繊維が例示できる。これらの繊維は、例えば、織布、不織布、ロービング、チョップドストランドマット、サーフェシングマット等の形状で強化繊維として用いることができる。
【００２３】
プリプレグとしては、市販のプリプレグを用いることができ、またプリプレグを複数層備えたものを用いてもよい。適用可能なプリプレグとしては、エポキシ樹脂を主成分とする熱硬化性樹脂をガラス繊維織布であるガラスクロスに含浸させたプリプレグ（Ｅ−６７、Ｅ−６７９、Ｅ−６７９Ｆ、日立化成工業社製）、ポリイミドに熱硬化成分を配合した樹脂組成物をガラスクロスに含浸させたプリプレグ（ＧＥＡ−Ｉ−６７１、日立化成工業社製）が挙げられる。
【００２４】
プリプレグにおける硬化性樹脂と強化繊維の配合比は、重量比で硬化性樹脂／強化繊維＝２０／８０〜８０／２０であることが好ましく、４０／６０〜６０／４０であることがより好ましい。
【００２５】
次に第２の硬化性樹脂を構成する成分について説明する。
【００２６】
第２の硬化性樹脂を構成する成分としては、フェノール樹脂、アミノ樹脂、エポキシ樹脂等の通常金属張積層板において層形成材料として用いられる樹脂組成物を用いることができるが、ポリアミドイミド及びアミド反応性化合物を含むポリアミドイミド系硬化性樹脂であることが好ましい。
【００２７】
第２の硬化性樹脂においては、ポリアミドイミド１００重量部に対する、アミド反応性化合物の重量部Ｘは、ポリアミドイミド中のアミド基量をＡ重量％、アミド反応性化合物中のアミド基量をＢ重量％、ポリアミドイミド中のケイ素量をＣ重量％、アミド反応性化合物中のケイ素量をＤ重量％としたときに、下記式（Ｉ）及び（ＩＩ）を満たすことが好ましい。これらの式が満たされない場合は、得られる金属張積層板の接着強度及び耐熱性が不十分となる傾向がある。
４≦（Ａ×１００＋Ｂ×Ｘ）／（１００＋Ｘ）≦１０ ・・・（Ｉ）
１≦（Ｃ×１００＋Ｄ×Ｘ）／（１００＋Ｘ）≦１５ ・・・（ＩＩ）
【００２８】
なお、アミド基量とは、アミド基を含む化合物の重量に占めるアミド基（ＣＯＮＨ）の重量％をいい、ケイ素量も同様に、アミド基を含む化合物の重量に占めるケイ素原子（Ｓｉ）の重量％をいう。
【００２９】
上記式（Ｉ）及び（ＩＩ）の条件を具備する場合には、ポリアミドイミド及びアミド反応性化合物の混合物中の全アミド基量が４〜１０重量％となり、全ケイ素量が１〜１５重量％となる。
【００３０】
上記式（Ｉ）及び（ＩＩ）の条件を具備するポリアミドイミドを含む第２の硬化性樹脂は、有機溶媒を用いてワニスとした場合における当該溶媒の揮発速度が速く、第２の硬化性樹脂の硬化を促進しない温度において、極めて容易に残存有機溶媒分を５重量％以下にできるという特徴を有する。また、かかる第２の硬化性樹脂を接着剤層に用いた接着剤層付きプリプレグを金属張積層板に適用することにより、金属箔との接着性及び耐熱性の優れた金属張積層板を得ることができる。これは、主に耐熱性の高いポリアミドイミド中にシロキサン構造を導入したポリアミドイミドに起因するものである。そして、上述のように式（Ｉ）及び（ＩＩ）の条件を具備させることで、残存有機溶媒を低減できるので、銅箔との積層工程において有機溶媒の揮発によるふくれの発生が少なく、金属張積層板のはんだ耐熱性を向上できる。
【００３１】
上記特性をより向上させることが可能なことから、上記式（Ｉ）における（Ａ×１００＋Ｂ×Ｘ）／（１００＋Ｘ）の下限は６が好ましく、上限は８が好ましい。そして同様の観点から上記式（ＩＩ）における（Ｃ×１００＋Ｄ×Ｘ）／（１００＋Ｘ）の下限は５が好ましく、上限は１０が好ましい。
【００３２】
第２の硬化性樹脂を構成するポリアミドイミドは、主鎖にシロキサン構造、アミド結合及びイミド結合を有するポリマーであるが、シロキサン構造とは、−ＳｉＯ−結合を有する構造をいう。なお、Ｓｉには一価の有機基が２つ結合していることが好ましい。
【００３３】
ポリアミドイミドは、例えば、上記一般式（１）で表される芳香族ジアミン及び上記一般式（２）で表されるシロキサンジアミンを含む混合物と、無水トリメリット酸と、を反応させてジイミドジカルボン酸を得、得られたジイミドジカルボン酸に芳香族ジイソシアネートを反応させて得ることができる。
【００３４】
上記一般式（１）で表される芳香族ジアミンにおけるＹ、すなわち炭素数１〜３の脂肪族炭化水素基は、−Ｃ（ＣＨ_３）_２−であることが好ましく、炭素数１〜３のハロゲン化脂肪族炭化水素基は−Ｃ（ＣＦ_３）_２−であることが好ましい。また、上記一般式（２）で表されるシロキサンジアミンにおいては、Ｒ^１は炭素数１〜６のアルキル基であることが好ましく、炭素数１〜３のアルキル基であることがより好ましく、Ｒ^２は、炭素数１〜６のアルキレン基であることが好ましく、炭素数１〜３のアルキレン基であることがより好ましい。
【００３５】
上記一般式（１）で表される芳香族ジアミンとしては、例えば、２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン（ＢＡＰＰ）、ビス［４−（３−アミノフェノキシ）フェニル］スルホン、ビス［４−（４−アミノフェノキシ）フェニル］スルホン、２，２−ビス［４−（４−アミノフェノキシ）フェニル］ヘキサフルオロプロパン、ビス［４−（４−アミノフェノキシ）フェニル］メタン、４，４’−ビス（４−アミノフェノキシ）ビフェニル、ビス［４−（４−アミノフェノキシ）フェニル］エーテル、ビス［４−（４−アミノフェノキシ）フェニル］ケトン、１，３−ビス（４−アミノフェノキシ）ベンゼン、１，４−ビス（アミノフェノキシ）ベンゼンが例示できる。
【００３６】
芳香族ジアミンとしては、下記一般式（４）で表される化合物を用いることが好ましく、ＢＡＰＰを用いることがより好ましい。なお、式中、Ｙは上記と同義である。
【化７】

【００３７】
上記一般式（２）で表されるシロキサンジアミンとしては、ジメチルシロキサン系両末端アミンを用いることが好ましく、かかる化合物はアミノ変性シリコーンオイルＸ−２２−１６１ＡＳ（アミン当量４５０）、Ｘ−２２−１６１Ａ（アミン当量８４０）、Ｘ−２２−１６１Ｂ（アミン当量１５００）（以上、信越化学工業社製）、ＢＹ１６−８５３（アミン当量６５０）、ＢＹ−１６−８５３Ｂ（アミン当量２２００）（以上、東レダウコーニングシリコーン社製）等として商業的に入手可能である。なお、これらは単独で、または組み合わせて用いることができる。
【００３８】
上述の芳香族ジアミン及びシロキサンジアミンの混合物と、無水トリメリット酸とを反応させることによりジイミドジカルボン酸を得ることができる。得られるジイミドジカルボン酸には、下記一般式（５ａ）及び下記一般式（５ｂ）で表される化合物が含まれる。
【化８】

【００３９】
式中、Ｚは、上記一般式（１）で表される化合物のアミノ基を除いた残基であり、Ｒ^１、Ｒ^２及びｎは上記と同義である。
【００４０】
芳香族ジアミン及びシロキサンジアミンを含むジアミン混合物と、無水トリメリット酸の反応においては、芳香族ジアミンのモル数をＡ、シロキサンジアミンのモル数をＢ、無水トリメリット酸のモル数をＣとすると、（Ａ＋Ｂ）／Ｃの値が１．０／２．０〜１．０／２．２となるようにして反応させることが好ましい。ＡとＢとの混合比率Ａ／Ｂは９９．９／０．１〜０／１００であることが好ましく、かかる混合比率は、Ｂのアミン当量に応じて決定することが好ましい。例えば、シロキサンジアミンのアミン当量が４００〜５００の場合、Ａ／Ｂは９９．９／０．１〜０／１００、アミン当量が８００〜１０００の場合、Ａ／Ｂは９９．９／０．１〜６０／４０、アミン当量が１５００〜１６００場合、Ａ／Ｂは９９．９／０．１〜６０／４０とすることが好ましい。Ａ、Ｂ及びＣを上記範囲内にすることにより、上記一般式（５ａ）及び（５ｂ）で表されるジイミドジカルボン酸がより生成しやすくなり、生成するポリアミドイミドにおける全アミド基量及び全ケイ素量について上記式（Ｉ）及び（ＩＩ）を具備させやすくなる。
【００４１】
ジイミドジカルボン酸は、まず、芳香族ジアミン及びシロキサンジアミンを含むジアミン混合物と無水トリメリット酸とを非プロトン性極性溶媒中、５０〜９０℃で反応させた後に、水と共沸可能な芳香族炭化水素を加え、１２０〜１８０℃で更に反応させて脱水閉環反応を生じさせることにより製造することが好ましい。非プロトン性極性溶媒としては、ジメチルアセトアミド、ジメチルホルムアミド、ジメチルスルホキシド、Ｎ−メチル−２−ピロリドン、４−ブチロラクトン、スルホラン等が例示でき、Ｎ−メチル−２−ピロリドンを用いることがより好ましい。
【００４２】
また、水と共沸可能な芳香族炭化水素としては、トルエン、ベンゼン、キシレン、エチルベンゼン等が例示でき、トルエンを用いることが好ましい。かかる芳香族炭化水素は非プロトン性極性溶媒に対して、重量比で０．１〜０．５となる重量を加えることが好ましい。そして、脱水閉環反応の終了後、更に温度を約１９０℃に上昇させて水と共沸可能な芳香族炭化水素を除去しておくことが好ましい。
【００４３】
上記の反応により得られたジイミドジカルボン酸に、芳香族ジイソシアネートを反応させることにより、ポリアミドイミドを得ることができる。
【００４４】
芳香族ジイソシアネートとしては、下記一般式（６）で表される化合物を用いることができる。
【化９】

【００４５】
式中、Ｗは少なくとも１つの芳香環を有する２価の有機基であり、−Ｃ_６Ｈ_４−ＣＨ_２−Ｃ_６Ｈ_４−で表される基、トリレン基及びナフチレン基からなる群から選ばれる少なくとも１つの基であることが好ましい。
【００４６】
上記一般式（６）で表される化合物としては、４，４’−ジフェニルメタンジイソシアネート（ＭＤＩ）、２，４−トリレンジイソシアネート、２，６−トリレンジイソシアネート、ナフタレン−１，５−ジイソシアネート、２，４−トリレンダイマー等が例示できる。
【００４７】
得られるポリアミドイミドは、下記一般式（７ａ）及び下記一般式（７ｂ）で表される繰り返し単位を有する化合物である。かかる繰り返し単位は、ブロック的に結合していてもよく、ランダム的に結合していてもよい。なお、式中、Ｚ、Ｗ、Ｒ^１、Ｒ^２及びｎは上記と同義である。
【化１０】

【００４８】
ジイミドジカルボン酸と芳香族ジイソシアネートとの反応は、水と共沸可能な芳香族炭化水素を除去した後、いったん溶液を室温まで冷却させてから、芳香族ジイソシアネートを加えて、約１９０℃で２時間程度反応させることが好ましい。かかる反応においては、生成したジイミドジカルボン酸１当量に対する芳香族ジイソシアネートの添加量は１．０〜１．５当量であることが好ましく、１．１〜１．３当量であることがより好ましい。芳香族ジイソシアネートの添加量が１．０当量未満であると、得られる接着剤層の可撓性が低下する傾向があり、また１．５当量を超えても、同様に得られる接着剤層の可撓性が低下する傾向がある。
【００４９】
アミド反応性化合物としては、アミド基と反応を生じる官能基を備えた熱硬化性樹脂を用いることができる。熱硬化性樹脂としては、多官能エポキシ化合物、ポリイミド樹脂、不飽和ポリエステル樹脂、ポリウレタン樹脂、ビスマレイミド樹脂、トリアジン−ビスマレイミド樹脂、フェノール樹脂等が例示でき、多官能エポキシ化合物を用いることが好ましい。アミド反応性化合物として多官能エポキシ化合物を用いることにより、得られる接着剤層の耐熱性だけでなく機械的特性及び電気的特性を向上させることができる。
【００５０】
多官能エポキシ化合物としては２個以上のエポキシ基を有する多官能エポキシ化合物を用いることが好ましく、３個以上のエポキシ基を有する多官能エポキシ化合物を用いることがより好ましい。
【００５１】
２個以上のエポキシ基を有する多官能エポキシ化合物としては、ビスフェノールＡ、ノボラック型フェノール樹脂、オルトクレゾールノボラック型フェノール樹脂等の多価フェノールとエピクロルヒドリンとを反応させてなるエポキシ樹脂；１，４−ブタンジオール等の多価アルコールとエピクロルヒドリンとを反応させてなるエポキシ樹脂；フタル酸、ヘキサヒドロフタル酸等の多塩基酸とエピクロルヒドリンとを反応させてなるポリグリシジルエステル；アミン、アミド又は複素環式窒素塩基を有する化合物のＮ−グリシジル誘導体；脂環式エポキシ樹脂等が例示できる。
【００５２】
３個以上のグリシジル基を有する多官能エポキシ化合物としては、ＺＸ−１５４８−２（東都化成社製）、ＤＥＲ−３３１Ｌ（ダウケミカル社製ビスフェノールＡ型エポキシ樹脂）、ＹＤＣＮ−１９５（東都化成社製クレゾールノボラック型エポキシ樹脂）等が例示できる。
【００５３】
アミド反応性化合物の配合量は、アミド基と反応を生じる官能基の数に応じて決定することができ、ポリアミドイミド１００重量部に対するアミド反応性化合物の重量部Ｘは、ポリアミドイミド中のアミド基量をＡ重量％、アミド反応性化合物中のアミド基量をＢ重量％、ポリアミドイミド中のケイ素量をＣ重量％、アミド反応性化合物中のケイ素量をＤ重量％としたときに、上記の式（Ｉ）及び（ＩＩ）を満たすように決定する。
【００５４】
アミド反応性化合物として多官能エポキシ化合物を用いる場合、第２の硬化性樹脂中に、更に多官能エポキシ化合物の硬化剤、硬化促進剤等を加えることが好ましい。多官能エポキシ化合物の硬化剤としては、従来公知のものを用いることができ、例えば、ジシアンジアミド、ジアミノジフェニルメタン、グアニル尿素等のアミン類；イミダゾール類；ヒドロキノン、レゾルシノール、ビスフェノールＡ及びこれらのハロゲン化物、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等の多官能フェノール類；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の酸無水物類等が挙げられ、また硬化促進剤としては、アルキル基置換イミダゾール、ベンゾイミダゾール等のイミダゾール類が挙げられる。
【００５５】
上記の硬化剤の配合量は、多官能エポキシ化合物におけるエポキシ当量に応じて決定することができ、例えば硬化剤としてアミン化合物を用いる場合、アミンの活性水素の当量と、多官能エポキシ化合物のエポキシ当量が等しくなるように配合する。また、硬化剤として多官能フェノール類又は酸無水物類を用いる場合、配合量は、多官能エポキシ化合物１当量に対して、フェノール性水酸基又はカルボキシル基が０．６〜１．２当量となるようにすることが好ましい。硬化促進剤を用いる場合は、硬化促進剤の配合量は多官能エポキシ化合物１００重量部に対して、０．００１〜１０重量部であることが好ましい。これらの硬化剤又は硬化促進剤の配合量が上記範囲より少ない場合は多官能エポキシ化合物の硬化が不充分となり、第２の硬化性樹脂の硬化後のガラス転移温度が低下する傾向があり、多い場合は残存の硬化剤又は硬化促進剤により第２の硬化性樹脂の硬化後の電気的特性が低下する傾向がある。
【００５６】
第２の硬化性樹脂中には、更に、硬化を阻害しない範囲で、充填剤、カップリング剤、難燃剤等をその他の成分として添加することができる。
【００５７】
次に、本発明の接着剤層付きプリプレグの製造方法について説明する。
【００５８】
本発明の接着剤層付きプリプレグの製造方法は、強化繊維を配した、Ｂステージ状態の第１の硬化性樹脂からなるプリプレグ上に、第２の硬化性樹脂を積層し接着剤層とする、接着剤層付きプリプレグの製造方法であって、硬化が完結しないようにプリプレグ及び第２の硬化性樹脂を加熱しつつ、プリプレグ上に第２の硬化性樹脂を積層することを特徴とするものである。
【００５９】
第２の硬化性樹脂は、公知の加熱手段（温風加熱、赤外線加熱、加熱圧着等）を用いて、加熱された状態でプリプレグ上に積層するが、かかる積層時には、プリプレグ及び第２の硬化性樹脂の両方の硬化が完結しないように加熱を行う必要がある。プリプレグに積層する接着剤層は、第２の硬化性樹脂を、好ましくは硬化が完結しないようにフィルム状にしたフィルム状硬化性樹脂、より好ましくはポリアミドイミドとアミド反応性化合物の反応が完結しないようにあらかじめフィルム状にしたフィルム状ポリアミドイミド系硬化性樹脂とし、それを積層することが好ましい。なお、硬化及び反応が完結したか否かは、示差走査熱量計（ＤＳＣ）により確認でき、金属張積層板の作製時の加熱温度で保持した時にＤＳＣで発熱ピークが見られれば、硬化及び反応が完結していない状態であるということができる。
【００６０】
フィルム状硬化性樹脂は、支持体上に、ジメチルアセトアミド、ジメチルホルムアミド、ジメチルスルホキシド、Ｎ−メチル−２−ピロリドン、γ−ブチロラクトン、スルホラン、シクロヘキサノン等の有機溶媒に溶解又は分散させた第２の硬化性樹脂を塗布した後、上記有機溶媒を除去して形成することが好ましい。なお、有機溶媒の除去を加熱により行う場合は、ポリアミドイミドとアミド反応性化合物との反応が完結しないように行う必要がある。
【００６１】
支持体としては、ポリエチレンテレフタレートやアルミ箔等が例示でき、これらの表面に離型処理を施したものがより好適である。特に、厚さ３０μｍ〜２００μｍのポリエチレンテレフタレートに離型処理を施したものを用いることが好ましい。
【００６２】
フィルム状硬化性樹脂をプリプレグ上に積層させる方法としては、例えばロールラミネートによる方法が挙げられる。すなわちフィルム状ポリアミドイミド系硬化性樹脂をプリプレグに接するように重ね、加熱されたロールの間を加圧しながら通過させることにより加熱しつつ積層させる。かかる方法においては、加熱されたロールの温度が積層温度に相当するため、積層温度の制御を容易に行うことが可能となる。積層温度は、使用する第２の硬化性樹脂に応じて決定することができ、例えば、アミド反応性化合物として多官能エポキシ化合物を用いる場合は、１５０℃以下であることが好ましく、８０〜１５０℃であることがより好ましく、１００〜１３０℃であることが特に好ましい。積層温度が１５０℃を超える場合、得られる接着剤層付きプリプレグを金属張積層板に適用した際に接着性が低下する傾向がある。一方、８０℃未満である場合は接着剤層とプリプレグとの密着性が低下する傾向がある。
【００６３】
次に、本発明の接着剤層付きプリプレグの製造方法により得られた接着剤層付きプリプレグの構成について、図面を参照しつつ、好適な実施形態を説明する。
【００６４】
図１は本発明の接着剤層付きプリプレグの一実施形態を示す断面図である。図１に示す接着剤層付きプリプレグ１は、プリプレグ２と、プリプレグ２上に形成された第２の硬化性樹脂からなる接着剤層４とを備えている。ここで、プリプレグ２における第１の硬化性樹脂と、接着剤層４を構成する第２の硬化性樹脂は、同一であってもよく、異なっていてもよいが、異なることが好ましい。
【００６５】
接着剤層付きプリプレグ１においては、プリプレグ２の厚さは、２０〜２５０μｍであることが好ましい。また、接着剤層４の厚さは３０μｍ以下とすることが好ましく、５〜２０μｍとすることがより好ましい。接着剤層４の厚さを３０μｍ以下とすることにより、接着剤層付きプリプレグ１を金属張積層板に用いた際に生じるそりを大幅に低減することが可能となる。そして、接着剤層４の硬化後の弾性率は５００〜２５００ＭＰａであることが好ましく、８００〜１５００ＭＰａであることがより好ましい。接着剤層４の硬化後の弾性率を上記範囲内とすることにより、接着性及び耐熱性が更に優れるようになる。
【００６６】
次に、本発明の接着剤層付きプリプレグの製造方法により得られた接着剤層付きプリプレグを用いた金属張積層板の製造方法について、図２を参照しつつ、好適な実施形態を説明する。
【００６７】
金属張積層板は、例えば、次のようにして製造することができる。すなわち、金属箔とプリプレグとをそれぞれ少なくとも一枚用いて、前記金属箔の少なくとも片面にプリプレグが接するように積層した後、加熱及び加圧することにより金属張積層板を製造することができる。そして、金属箔の少なくとも一枚は、粗面化処理されていない金属箔であり、少なくとも金属箔に隣接させて加熱及び加圧するプリプレグとして、接着剤層が金属箔と接するように配置された上述の接着剤層付きプリプレグの製造方法により得られた接着剤層付きプリプレグを用いることが好ましい。
【００６８】
図２（ａ）は、２枚の粗面化処理されていない金属箔２２と、３枚の積層体形成用プリプレグ１０と、２枚の接着剤層付きプリプレグ１とを積層する工程を模式的に示す断面図である。同工程においては、３枚の積層体形成用プリプレグ１０を互いに隣接するように積層し、積層された積層体形成用プリプレグ１０の上面と下面に、接着剤層付きプリプレグ１を介して金属箔２２を積層する。この場合において、接着剤層付きプリプレグ１における接着剤層４は、金属箔２２と接するように配置する。
【００６９】
金属箔２２としては、銅箔やアルミニウム箔等の金属箔を用いることができ、厚さは５〜２００μｍであることが好ましい。また、厚さ０．５〜１５μｍの銅箔層と厚さ１０〜３００μｍの銅箔層の間に、ニッケル、ニッケル−リン、ニッケル−スズ合金、ニッケル−鉄合金、鉛、鉛−スズ合金等からなる中間層を設けた３層構造の複合箔や、アルミニウムと銅箔を複合した２層構造の複合箔を用いることもできる。金属箔２２の表面粗さはＲｚ＝５μｍ以下であることが好ましく、Ｒｚ＝２μｍ以下であることがより好ましい。なお、Ｒｚは、ＪＩＳ Ｂ ０６０１に規定された十点平均粗さをいう。
【００７０】
上述のようにして積層が終了した後に、全体を加熱及び加圧することにより、金属張積層板を得ることができる。図２（ｂ）は、得られた金属張積層板３０を模式的に示す断面図である。同図に示す金属張積層板３０は、積層体形成用プリプレグ１０の硬化物である積層体形成用プリプレグ硬化物２０の３層を中心層として、この上面及び下面に、接着剤層付きプリプレグ１の硬化物（プリプレグ硬化物１２と接着剤層硬化物１４とから構成される。）と金属箔２２とがこの順に積層された構成を有している。
【００７１】
なお、積層及び硬化は、真空プレス等を用いて行うことができ、硬化の際の温度は、１５０〜２８０℃であることが好ましく、１８０〜２５０℃であることがより好ましい。また圧力は０．５〜２０ＭＰａであることが好ましく、１〜８ＭＰａであることがより好ましい。
【００７２】
金属張積層板３０においては、金属箔２２が接着剤層硬化物１４を介してプリプレグ硬化物１２に接着され、また硬化によりプリプレグ硬化物１２と積層体形成用プリプレグ硬化物２０が一体化され積層体を形成していることから、金属箔２２は金属張積層板３０において上記積層体と強固に接着しており、金属張積層板３０に微細な配線パターンを形成させた場合においても、金属箔２２からなる導体層の剥離を生じることが極めて少なくなる。また、接着剤層硬化物１４は、本発明の接着剤層付きプリプレグ１における接着剤層４の硬化物であるため、高い耐熱性を有しており、高温に晒されたときにふくれ等の発生が大幅に低減される。
【００７３】
【実施例】
以下、実施例により本発明を更に詳細に説明するが、本発明はこれらの実施例に限定されるものではない。
【００７４】
［ポリアミドイミドの合成］
（合成例１）
還流冷却器を連結したコック付き２５ｍＬの水分定量受器、温度計、攪拌器を備えた１Ｌのセパラブルフラスコに、芳香族ジアミンとして２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン（ＢＡＰＰ）４３．１ｇ（０．１０５ｍｏｌ）、シロキサンジアミンとして反応性シリコンオイルＫＦ８０１０（信越化学社製、アミン当量４４５）４０．１ｇ（０．０４５ｍｏｌ）、無水トリメリット酸（ＴＭＡ）６０．５ｇ（０．３１５ｍｏｌ）、非プロトン性極性溶媒としてＮ−メチル−２−ピロリドン（ＮＭＰ）４４０ｇを入れ、８０℃で３０分間攪拌した。
【００７５】
攪拌終了後、水と共沸可能な芳香族炭化水素としてトルエン１００ｍＬを加え、温度を１６０℃に上昇させて２時間還流させた。水分定量受器に水が約５．４ｍＬ以上たまり、水の留出が見られなくなっていることを確認した後、水分定量受器中の水を除去しながら温度を１９０℃まで上昇させ、トルエンを除去した。
【００７６】
フラスコの溶液を室温まで戻した後、芳香族ジイソシアネートとして４，４’−ジフェニルメタンジイソシアネート（ＭＤＩ）４５．１ｇ（０．１８ｍｏｌ）を加え、温度を１９０℃に上昇させて２時間反応させ、アミド基量８．１重量％、ケイ素量６．９重量％のポリアミドイミドのＮＭＰ溶液を得た。
【００７７】
（合成例２）
還流冷却器を連結したコック付き２５ｍＬの水分定量受器、温度計、攪拌器を備えた１Ｌのセパラブルフラスコに、芳香族ジアミンとしてＢＡＰＰ４１．１ｇ（０．１０ｍｏｌ）、シロキサンジアミンとして反応性シリコンオイルＫＦ８０１０の９０．０ｇ（０．１０ｍｏｌ）、ＴＭＡ８０．７ｇ（０．４２ｍｏｌ）、非プロトン性極性溶媒としてＮＭＰ５０５ｇを入れ、８０℃で３０分間攪拌した。
【００７８】
攪拌終了後、水と共沸可能な芳香族炭化水素としてトルエン１００ｍＬを加え、温度を１６０℃に上昇させて２時間還流させた。水分定量受器に水が約７．２ｍＬ以上たまり、水の留出が見られなくなっていることを確認した後、水分定量受器中の水を除去しながら温度を１９０℃まで上昇させ、トルエンを除去した。
【００７９】
フラスコの溶液を室温まで戻した後、芳香族ジイソシアネートとしてＭＤＩ６０．１ｇ（０．２４ｍｏｌ）を加え、温度を１９０℃に上昇させて２時間反応させ、アミド基量７．４重量％、ケイ素量１０．９重量％のポリアミドイミドのＮＭＰ溶液を得た。
【００８０】
（合成例３）
還流冷却器を連結したコック付き２５ｍＬの水分定量受器、温度計、攪拌器を備えた１Ｌのセパラブルフラスコに、芳香族ジアミンとしてＢＡＰＰ５５．４ｇ（０．１３５ｍｏｌ）、シロキサンジアミンとして反応性シリコンオイルＸ−２２−１６１Ｂ（信越化学工業社製、アミン当量１５６０）４６．８ｇ（０．０１５ｍｏｌ）、ＴＭＡ６０．５ｇ（０．３１５ｍｏｌ）、非プロトン性極性溶媒としてＮＭＰ４８５ｇを入れ、８０℃で３０分間攪拌した。
【００８１】
攪拌終了後、水と共沸可能な芳香族炭化水素としてトルエン１００ｍＬを加え、温度を１６０℃に上昇させて２時間還流させた。水分定量受器に水が約５．４ｍＬ以上たまり、水の留出が見られなくなっていることを確認した後、水分定量受器中の水を除去しながら温度を１９０℃まで上昇させ、トルエンを除去した。
【００８２】
フラスコの溶液を室温まで戻した後、芳香族ジイソシアネートとしてＭＤＩ４５．１ｇ（０．１８ｍｏｌ）を加え、温度を１９０℃に上昇させて２時間反応させ、アミド基量７．２重量％、ケイ素量９．０重量％のポリアミドイミドのＮＭＰ溶液を得た。
【００８３】
［第２の硬化性樹脂の調製］
（調製例１）
合成例１で得られたポリアミドイミドのＮＭＰ溶液３００ｇ（固形分３０重量％）、アミド反応性化合物としてエポキシ樹脂であるＺＸ−１５４８−２（東都化成社製、リン含有多官能エポキシ樹脂）２０ｇ（樹脂固形分５０重量％のジメチルアセトアミド溶液）、２−エチル−４−メチルイミダゾール０．２ｇを配合し、組成物が均一になるまで約１時間攪拌した後、脱泡のため２４時間室温で静置して、全アミド基量７．３重量％、全ケイ素量６．３重量％の第２の硬化性樹脂のワニスを得た。
【００８４】
（調製例２）
合成例１で得られたポリアミドイミドのＮＭＰ溶液２６７ｇ（固形分３０重量％）、アミド反応性化合物としてエポキシ樹脂であるＺＸ−１５４８−２の４０ｇ（樹脂固形分５０重量％のジメチルアセトアミド溶液）、２−エチル−４−メチルイミダゾール０．２ｇを配合し、樹脂組成物が均一になるまで約１時間攪拌した後、脱泡のため２４時間室温で静置して、全アミド基量６．４重量％、全ケイ素量５．６重量％の第２の硬化性樹脂のワニスを得た。
【００８５】
（調製例３）
合成例１で得られたポリアミドイミドのＮＭＰ溶液３００ｇ（固形分３０重量％）、アミド反応性化合物としてエポキシ樹脂であるＤＥＲ−３３１Ｌ（ダウケミカル社製、ビスフェノールＡ型エポキシ樹脂）２０ｇ（樹脂固形分５０重量％のジメチルアセトアミド溶液）、２−エチル−４−メチルイミダゾール０．２ｇを配合し、樹脂組成物が均一になるまで約１時間攪拌した後、脱泡のため２４時間室温で静置して、全アミド基量７．３重量％、全ケイ素量６．３重量％の第２の硬化性樹脂のワニスを得た。
【００８６】
（調製例４）
合成例１で得られたポリアミドイミドのＮＭＰ溶液３００ｇ（固形分３０重量％）、アミド反応性化合物としてエポキシ樹脂であるＹＤＣＮ−１９５（東都化成社製、クレゾールノボラック型エポキシ樹脂）２０ｇ（樹脂固形分５０重量％のジメチルアセトアミド溶液）、２−エチル−４−メチルイミダゾール０．２ｇを配合し、樹脂組成物が均一になるまで約１時間攪拌した後、脱泡のため２４時間室温で静置して、全アミド基量７．３重量％、全ケイ素量６．３重量％の第２の硬化性樹脂のワニスを得た。
【００８７】
（調製例５）
合成例２で得られたポリアミドイミドのＮＭＰ溶液３００ｇ（固形分３５重量％）、アミド反応性化合物としてエポキシ樹脂であるＺＸ−１５４８−２の２０ｇ（樹脂固形分５０重量％のジメチルアセトアミド溶液）、２−エチル−４−メチルイミダゾール０．３ｇを配合し、樹脂組成物が均一になるまで約１時間攪拌した後、脱泡のため２４時間室温で静置して、全アミド基量６．５重量％、全ケイ素量９．８重量％の第２の硬化性樹脂のワニスを得た。
【００８８】
（調製例６）
合成例３で得られたポリアミドイミドのＮＭＰ溶液３００ｇ（固形分３０重量％）、アミド反応性化合物としてエポキシ樹脂であるＺＸ−１５４８−２の２０ｇ（樹脂固形分５０重量％のジメチルアセトアミド溶液）、２−エチル−４−メチルイミダゾール０．３ｇを配合し、樹脂組成物が均一になるまで約１時間攪拌した後、脱泡のため２４時間室温で静置して、全アミド基量４．４重量％、全ケイ素量８．１重量％の第２の硬化性樹脂のワニスを得た。
【００８９】
［接着剤層付きプリプレグの作製］
（実施例１）
調製例１で得られた第２の硬化性樹脂ワニスを、厚さ５０μｍのポリエチレンテレフタレートフィルム（ＰＥＴフィルム、ピューレックス、帝人社製）に、接着剤層の乾燥後の厚さが１５μｍとなるように塗布し、１３０℃で２０分間加熱、乾燥することにより、揮発成分を５〜７重量％含む接着剤付きのフィルムを得た。
【００９０】
次に、得られた接着剤層付きのフィルムを、接着剤層が接触するようにプリプレグ（ＧＥＡ−Ｉ−６７１、日立化成工業社製）上に重ねて、ホットロール温度１２０℃、速度０．２ｍ／分の条件でホットロールラミネータによりラミネートを行った後、ＰＥＴフィルムを剥離して、プリプレグ上に接着剤層が形成された実施例１の接着剤層付きプリプレグを得た。
【００９１】
（実施例２〜６）
調製例１で得られた第２の硬化性樹脂のワニスに替えて調製例２〜６の第２の硬化性樹脂のワニスを用いた以外は、実施例１と同様にして実施例２〜６の接着剤層付きプリプレグを得た。なお、調製例２〜６の第２の硬化性樹脂のワニスを用いた場合が実施例２〜６にそれぞれ該当する。
【００９２】
（比較例１）
ホットロール温度１２０℃に替えて、１６０℃、１８０℃及び２８℃でラミネートを行った以外は実施例１と同様にして接着剤層付きプリプレグを作製した。しかし、ホットロール温度１８０℃でラミネートを行った場合は、接着剤層からＰＥＴフィルムを剥がすことが不可能であり、また、２８℃で行った場合は接着剤層付きのフィルムとプリプレグとの接着が不可能であった。そこで、ホットロール温度１６０℃の場合の接着剤層付きプリプレグを比較例１として試験に供した。
【００９３】
（実施例７〜１１）
調製例１で得られた第２の硬化性樹脂のワニスを、接着剤層の乾燥後の厚さが５、１０、２０、３０、５０μｍとなるように塗布した以外は、実施例１と同様にして実施例７〜１１のプリプレグを得た。なお、接着剤層の乾燥後の厚さを５、１０、２０、３０、５０μｍとしたものがそれぞれ実施例７、８、９、１０、１１に該当する。
【００９４】
［接着強度、はんだ耐熱性及び弾性率の測定］
実施例１〜６、比較例１の接着剤層付きプリプレグを、３枚のプリプレグ（ＧＥＡ−Ｉ−６７１）を積層した積層体の両面にプリプレグが接触するようにしてそれぞれ積層した後、最外層両面の接着剤層にそれぞれ表面粗さの異なる銅箔としてＦ０−ＷＳ−１２（古河電工社製、Ｒｚ＝１．８μｍ）、ＳＬＰ−１２（日本電解社製）の光沢面（Ｒｚ＝２．０μｍ）又はＧＴＳ−１２（古河サーキットフォイル社製、Ｒｚ＝８．０μｍ）をそれぞれ積層させ、真空プレスを用いて２３０℃、９０分、４．０ＭＰａの条件でプレスを行うことにより金属張積層板を得た。
【００９５】
得られたそれぞれの金属張積層板における銅箔を、それぞれ９０度方向に引き剥がす際の引き剥がし強さ（９０°剥離強さ、ＪＩＳ Ｃ ６４８１に準拠）を測定することにより接着強度の測定を行った。
【００９６】
次に、上記でＲｚ＝１．８μｍの銅箔を用いて得られた金属張積層板を、２０ｍｍ×２０ｍｍに切断したものをはんだ耐熱性試験用の試料とし、この試料を２６０℃及び２８８℃のはんだ浴にそれぞれ浸漬して、ふくれ又は金属箔の剥がれが生じていないかを目視により確認してはんだ耐熱性の評価を行った。なお、はんだ耐熱性の評価は、はんだ浴に試料を浸漬してからふくれ又は金属箔の剥がれが見られるまでの時間を測定し、得られた時間を測定値とした。
【００９７】
また、接着剤層を有していないプリプレグを用いた場合との比較を行うため、参考例１として５枚のプリプレグ（ＧＥＡ−Ｉ−６７１）を積層した積層体の両面に、Ｒｚ＝１．８μｍの銅箔を積層させ、真空プレスを用いて２３０℃、９０分、４．０ＭＰａの条件でプレスを行い金属張積層板を用いて上記と同様に接着強度及びはんだ耐熱性の測定を行った。
【００９８】
更に、接着剤層の硬化後の弾性率を測定するため、以下の試験を行った。まず、調製例１〜６で得られた第２の硬化性樹脂ワニスを厚さ５０μｍのポリエチレンテレフタレートフィルム（ＰＥＴフィルム）に乾燥後の厚さが８０μｍとなるようにそれぞれ塗布し、１３０℃で３０分間加熱して溶媒を揮発させるとともに硬化させた。硬化後、ＰＥＴフィルムを剥離して第２の硬化性樹脂の硬化物を得、得られた第２の硬化性樹脂の硬化物をＳＵＳ製の枠に挟んで、更に２３０℃で９０分の加熱を行い、厚さが８０μｍであるフィルム状硬化性樹脂を得た。そして、得られたフィルム状硬化性樹脂の３０℃における弾性率を動的粘弾性測定装置（レオロジー社製）を用いて測定した。
【００９９】
上記接着強度及びはんだ耐熱性の測定により得られた結果を合わせて表１に示す。また、弾性率の測定結果を、同様の第２の硬化性樹脂ワニスを用いたプリプレグの欄に記載した。
【表１】

表１に示すように、実施例１〜６の接着剤層付きプリプレグを用いた金属張積層板では、いずれの表面粗さを有する銅箔であっても０．８〜１．４ｋＮ／ｍの接着強度を示し、また、いずれの温度のはんだ浴に浸漬しても、３分以上ふくれ又は金属箔の剥がれ等の異常の発生は見られなかったのに対し、比較例１の接着剤層付きプリプレグを用いた金属張積層板及び参考例１では、０．２〜０．６ｋＮ／ｍの接着強度を示し、また、はんだ浴に浸漬してから２０秒以内でふくれ又は金属箔の剥がれが見られた。
【０１００】
［接着剤層の厚さによる影響の評価］
実施例７〜１１の接着剤層付きプリプレグを、その接着剤層が接触するようにして３枚のプリプレグを積層した積層体の片面に積層させた後、接着剤層に銅箔としてＦ０−ＷＳ−１２（Ｒｚ＝１．８μｍ）又はＳＬＰ−１２の光沢面（Ｒｚ＝２．０μｍ）を積層させ、真空プレスを用いて２３０℃、９０分、４．０ＭＰａの条件でプレスを行うことにより金属張積層板を得た。
【０１０１】
得られた金属張積層板をそれぞれ用い、そりの発生の確認及び接着強度の測定を行った。なお、そりの発生は、金属張積層板にそりが発生しているか否かを目視により確認し、接着強度の測定は上述の方法と同様に行った。
【０１０２】
得られたそりの発生の確認及び接着強度の測定の結果をまとめて表２に示す。なお、表２においては、そりの発生の見られなかったものを○で示し、そりの発生の見られたものを×で示した。
【表２】

【０１０３】
表２に示すように、いずれの接着剤層付きプリプレグを用いた金属張積層板でも、０．６〜１．１ｋＮ／ｍの接着強度を示したが、接着剤層の厚さが５０μｍである接着剤層付きプリプレグを用いた金属張積層板は、銅箔を内側にするように表面にそりが発生した。
【０１０４】
［回路形成性の評価］
実施例１、６の接着剤層付きプリプレグを、そのプリプレグが接触するようにして４枚のプリプレグを積層した積層体の両面に積層した後、一方の接着剤層にＳＬＰ−１００（日本電解社製）を積層し、もう一方の接着剤層に表面粗さの異なる銅箔（Ｒｚ＝１．８μｍ、Ｒｚ＝２．０μｍ又はＲｚ＝８．０μｍ）をそれぞれ積層させ、真空プレスを用いて２３０℃、９０分、４．０ＭＰａの条件でプレスを行うことにより金属張積層板を得た。
【０１０５】
得られた金属張積層板をそれぞれ用い、金属張積層板における一方の面に存在するＳＬＰ−１００表面に全面レジストを形成し、また、他方の面に存在するそれぞれ表面粗さの異なる銅箔上に、ライン幅／スペース幅（Ｌ／Ｓ）が、２０μｍ／２０μｍ、３０μｍ／３０μｍ、４０μｍ／４０μｍ又は５０μｍ／５０μｍである櫛型レジストパターンをそれぞれ形成した。そして、塩化第二鉄溶液を用いてエッチングを行うことにより未保護の銅箔を除去した後、レジストを剥離して配線パターンを形成させた。
【０１０６】
配線パターンが形成された金属張積層板の回路形成性の評価は、顕微鏡を用いて行い、この評価は回路形成が可能であったライン幅／スペース幅（Ｌ／Ｓ）の最小値を回路形成性の値とした。
【０１０７】
また、接着剤層を有していないプリプレグを用いた場合との比較を行うため、参考例２として５枚のプリプレグ（ＧＥＡ−Ｉ−６７１）を積層した積層体の両面に、上記と同様に銅箔を積層して得られた金属張積層板を用い、上記と同様にして回路形成性の評価を行った。
【０１０８】
得られた回路形成性の評価結果をまとめて表３に示す。
【表３】

【０１０９】
表３に示すように、実施例１又は６の接着剤層付きプリプレグを用いた金属張積層板では、比較的平滑な金属箔表面（Ｒｚ＝１．８μｍ又は２．０μｍ）を有する銅箔を用いた金属張積層板であっても、エッチング時の残銅の除去を短時間で行うことができ、ライン幅／スペース幅＝２０μｍ／２０μｍで断面形状が矩形に近い良好な配線パターンが得られた。それに対して、参考例２では、Ｒｚ＝１．８μｍ又は２．０μｍの銅箔を用いた場合において銅箔が一部剥離した。なお、Ｒｚ＝８．０μｍの銅箔を用いた場合は、いずれの金属張積層板でも剥離は生じなかったが、エッチング時に銅箔面上の残銅の除去に長時間を要したために、ラインの上部が細い蒲鉾型となる傾向が見られた。このため、ライン幅／スペース幅は４０μｍ／４０μｍが良好な配線パターンの得られる限界であった。
【０１１０】
【発明の効果】
以上説明したように、本発明の接着剤層付きプリプレグによれば、金属張積層板の製造にあたり、粗面化処理されていない平滑な表面を有する導体層を用いた場合でも、導体層と積層体との接着性を良好にすることができ、また高温条件下におけるふくれの発生を低減することが可能な接着剤層付きプリプレグの製造方法を提供することが可能となる。
【図面の簡単な説明】
【図１】接着剤層付きプリプレグの一実施形態を示す断面図である。
【図２】（ａ）は、２枚の粗面化処理されていない金属箔２２と、３枚の積層体形成用プリプレグ１０と、２枚の接着剤層付きプリプレグ１とを積層する工程を模式的に示す断面図であり、（ｂ）は、得られた金属張積層板４０を模式的に示す断面図である。
【符号の説明】
１・・・接着剤層付きプリプレグ、２・・・プリプレグ、４・・・接着剤層、１０・・・積層体形成用プリプレグ、１２・・・プリプレグ硬化物、１４・・・接着剤層硬化物、２０・・・積層体形成用プリプレグ硬化物、２２・・・金属箔、３０・・・金属張積層板。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a prepreg with an adhesive layer and a prepreg with an adhesive layer.
[0002]
[Prior art]
As a substrate for a printed wiring board, many substrates obtained by laminating a plurality of prepregs obtained by impregnating a resin having an electrical insulating property with a reinforcing fiber such as a glass cloth and heating and pressurizing the prepregs are often used. Used. As a method for forming a conductor layer having a wiring pattern on such a substrate, a subtractive method is known. In such a method, a metal-clad laminate obtained by laminating a plurality of prepregs as described above to obtain a laminate, and then laminating and integrating a metal foil on the surface (one or both surfaces) is used. The wiring pattern is formed by etching the metal foil in the metal-clad laminate.
[0003]
And, as the electrically insulating resin used for the metal-clad laminate, a thermosetting resin such as a phenol resin, an epoxy resin, a polyimide resin, a bismaleimide-triazine resin, or the like, a fluorine resin, a polyphenylene ether resin, or the like. Such a thermoplastic resin is used.
[0004]
Conventional metal-clad laminates are formed by electrically or chemically roughening the surface of the metal foil to be bonded to the prepreg to form fine irregularities on the surface. Impregnating the resin impregnated into the metal foil to exhibit an anchor effect and improve the adhesive force between the metal foil and the laminate (for example, see Non-Patent Document 1).
[0005]
[Non-patent document 1]
Electronic Materials Editing Dept., "High Density Printed Wiring Board Technology", Industrial Research Committee, May 20, 1986, p. 149-157
[0006]
[Problems to be solved by the invention]
By the way, since the magnetic lines of force generated near the current flowing in the conductor layer interfere particularly with the center of the conductor, a skin effect in which the current concentrates on the surface of the conductor due to such interference appears, and as a result, the resistance in the conductor decreases. It is known to increase. Since the increase in resistance due to the skin effect is more remarkable as the surface of the conductor layer is roughened, when a roughened metal foil is used as in the above-described conventional technique, the high frequency of a signal to be transmitted is high. Therefore, it has become an obstacle to improve the processing speed.
[0007]
Therefore, in order to improve the processing speed, it is necessary to smooth the surface of the conductor layer, but by smoothing the surface of the conductor layer, the anchor effect cannot be obtained, and the laminate and the metal foil in the metal-clad laminate are not It was difficult to achieve both the adhesion between the laminate and the metal foil and the smoothness of the surface of the conductor layer, for example, such that the adhesion of the conductor layer was reduced and the conductor layer was peeled off.
[0008]
In addition, as the processing speed of electronic devices increases, the number of I / Os of the mounted MPU increases, and the number of terminals for connecting the MPU by the wire bonding method also increases. Therefore, it is necessary to cope with the increase in the number of terminals by miniaturizing the wiring pattern and narrowing the terminal width, but in the conventional metal-clad laminate, such miniaturization causes the conductor layer to peel off from the laminate. There was a problem.
[0009]
Furthermore, with the miniaturization and high density of information terminal devices, the mode of mounting components on printed wiring boards mounted on them has shifted from pin insertion type to surface mount type, and in recent years, BGA (ball An area array type represented by a grid array) has become mainstream. A mounting component such as a BGA is mounted on a substrate by a wire bonding method of performing pressure bonding by heat and sound waves. In such a mounting method, since the entire substrate is exposed to a high temperature of 150 ° C. or more, it is used for the substrate. The electrically insulating resin to be used is required to have high heat resistance which does not cause blistering even at high temperatures.
[0010]
The present invention has been made in view of the above, and in the production of a metal-clad laminate, even when using a conductor layer having a smooth surface that has not been subjected to surface roughening treatment, the adhesion between the conductor layer and the laminate It is an object of the present invention to provide a method for producing a prepreg with an adhesive layer, which can improve the swelling and reduce the occurrence of blisters under high temperature conditions. Another object of the present invention is to provide a prepreg with an adhesive layer obtained by such a production method.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a method for producing a prepreg with an adhesive layer according to the present invention comprises laminating a second curable resin on a prepreg made of a first curable resin in a B-stage state, on which reinforcing fibers are arranged. A method for producing a prepreg with an adhesive layer, wherein the prepreg and the second curable resin are heated so that curing is not completed; It is characterized by laminating resin.
[0012]
According to the method for manufacturing a prepreg with an adhesive layer described above, the prepreg and the second curable resin are heated and the second curable resin is laminated on the prepreg, so that the formed adhesive layer and prepreg Adhesion is improved. In addition, since lamination is performed before curing is completed, when a metal-clad laminate is produced by heating and pressing together with a metal foil having a smooth surface, a reaction proceeds at a metal foil interface and a prepreg interface, and the metal proceeds. The foil adheres firmly to the prepreg via the adhesive layer.
[0013]
In the method for producing a prepreg with an adhesive layer according to the present invention, the second curable resin may be a polyamideimide having a siloxane structure in a main chain and an amide reaction having a functional group which reacts with an amide group of the polyamideimide. And a polyamide-imide-based curable resin containing the polyamide-imide-based resin on the prepreg while heating the prepreg and the polyamide-imide-based curable resin so that the curing of the prepreg and the reaction are not completed. It is preferable to laminate a curable resin.
[0014]
In the above production method, a composition containing polyamideimide is used as the second curable resin, and the polyamideimide contained in the second curable resin has high heat resistance, and thus is obtained. The adhesive layer rarely causes abnormalities such as blisters even when exposed to high temperatures.
[0015]
The polyamide-imide curable resin laminated on the prepreg is preferably a film-like polyamide-imide curable resin obtained by molding the polyamide-imide curable resin into a film so that the reaction is not completed.
[0016]
In the method for producing a prepreg with an adhesive layer, the smoothness of the adhesive layer formed on the prepreg can be improved by using a polyamideimide-based curable resin that has been formed into a film in advance, and thus the metal foil having a smooth surface The adhesiveness with respect to can be significantly improved.
[0017]
The polyamideimide is a diimidedicarboxylic acid obtained by reacting a mixture containing an aromatic diamine represented by the following general formula (1) and a siloxane diamine represented by the following general formula (2) with trimellitic anhydride. Is preferably a polyamideimide obtained by reacting an aromatic diisocyanate.
Embedded image

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[Wherein, X is a functional group represented by the following general formula (3a) or (3b); ¹ Is an alkyl group, a phenyl group or a substituted phenyl group, R ² Represents an alkylene group, a phenylene group or a substituted phenylene group, and n represents an integer of 1 to 15.
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Here, Y is an aliphatic hydrocarbon group having 1 to 3 carbon atoms, a halogenated aliphatic hydrocarbon group having 1 to 3 carbon atoms, a sulfonyl group, an ether group, a carbonyl group, or a single bond. ¹ And R ² May be the same or different. ]
[0018]
By including the polyamideimide obtained by such a reaction in the second curable resin, the adhesiveness of the metal-clad laminate can be further improved.
[0019]
The amide-reactive compound is preferably a polyfunctional epoxy compound having two or more epoxy groups, and heating at the time of lamination is preferably performed at 80 to 150 ° C. Thereby, the adhesiveness and heat resistance of the obtained metal-clad laminate can be further improved.
[0020]
The present invention also provides a prepreg with an adhesive layer obtained by the above production method.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described.
[0022]
First, the prepreg will be described.
The prepreg can be obtained by impregnating the reinforcing fibers with the first curable resin and then bringing the first curable resin into a semi-cured state (B stage). As the first curable resin, it is preferable to use a thermosetting resin such as an epoxy resin, a polyimide resin, and a phenol resin. Examples of the reinforcing fibers include glass fibers made of E glass, D glass, S glass, Q glass, and the like, organic fibers made of polyimide, polyester, tetrafluoroethylene, and the like, and fibers obtained by mixing these. These fibers can be used as reinforcing fibers in the form of, for example, a woven fabric, a nonwoven fabric, a roving, a chopped strand mat, a surfacing mat, or the like.
[0023]
As the prepreg, a commercially available prepreg can be used, or a prepreg having a plurality of prepregs may be used. Examples of applicable prepregs include prepregs (E-67, E-679, E-679F, manufactured by Hitachi Chemical Co., Ltd.) in which a thermosetting resin mainly composed of an epoxy resin is impregnated into a glass cloth which is a glass fiber woven fabric. ), A prepreg (GEA-I-671, manufactured by Hitachi Chemical Co., Ltd.) obtained by impregnating a glass cloth with a resin composition obtained by mixing a thermosetting component with polyimide.
[0024]
The compounding ratio of the curable resin and the reinforcing fiber in the prepreg is preferably 20/80 to 80/20, more preferably 40/60 to 60/40 by weight ratio.
[0025]
Next, components constituting the second curable resin will be described.
[0026]
As a component constituting the second curable resin, a resin composition which is usually used as a layer forming material in a metal-clad laminate such as a phenol resin, an amino resin, and an epoxy resin can be used. It is preferably a polyamide-imide-based curable resin containing a hydrophilic compound.
[0027]
In the second curable resin, the weight part X of the amide-reactive compound with respect to 100 weight parts of the polyamideimide is such that the amount of the amide group in the polyamideimide is A% by weight, and the amount of the amide group in the amide-reactive compound is B weight. %, The silicon content in the polyamideimide is C weight%, and the silicon content in the amide reactive compound is D weight%, it is preferable that the following formulas (I) and (II) are satisfied. When these formulas are not satisfied, the resulting metal-clad laminate tends to have insufficient adhesive strength and heat resistance.
4 ≦ (A × 100 + B × X) / (100 + X) ≦ 10 (I)
1 ≦ (C × 100 + D × X) / (100 + X) ≦ 15 (II)
[0028]
The amount of the amide group means the weight% of the amide group (CONH) in the weight of the compound containing the amide group, and the amount of silicon is similarly the weight of the silicon atom (Si) in the weight of the compound containing the amide group. %.
[0029]
When the conditions of the above formulas (I) and (II) are satisfied, the total amide group content in the mixture of the polyamideimide and the amide reactive compound is 4 to 10% by weight, and the total silicon content is 1 to 15% by weight. It becomes.
[0030]
The second curable resin containing polyamide imide satisfying the conditions of the above formulas (I) and (II) has a high volatilization rate of the solvent when a varnish is formed using an organic solvent, and the second curable resin At a temperature that does not promote the curing of the compound, the residual organic solvent content can be extremely easily reduced to 5% by weight or less. Further, by applying a prepreg with an adhesive layer using the second curable resin to the adhesive layer to a metal-clad laminate, a metal-clad laminate excellent in adhesiveness to metal foil and heat resistance is obtained. be able to. This is mainly attributable to a polyamideimide obtained by introducing a siloxane structure into a polyamideimide having high heat resistance. By satisfying the conditions of the formulas (I) and (II) as described above, the amount of residual organic solvent can be reduced. The solder heat resistance of the laminate can be improved.
[0031]
Since the above characteristics can be further improved, the lower limit of (A × 100 + B × X) / (100 + X) in the above formula (I) is preferably 6 and the upper limit is preferably 8. From the same viewpoint, the lower limit of (C × 100 + D × X) / (100 + X) in the above formula (II) is preferably 5 and the upper limit is preferably 10.
[0032]
Polyamide imide constituting the second curable resin is a polymer having a siloxane structure, an amide bond, and an imide bond in a main chain. The siloxane structure refers to a structure having a -SiO- bond. Preferably, two monovalent organic groups are bonded to Si.
[0033]
Polyamide imide is obtained by reacting a mixture containing an aromatic diamine represented by the above general formula (1) and a siloxane diamine represented by the above general formula (2) with trimellitic anhydride to obtain diimide dicarboxylic acid. And reacting the resulting diimide dicarboxylic acid with an aromatic diisocyanate.
[0034]
Y in the aromatic diamine represented by the general formula (1), that is, an aliphatic hydrocarbon group having 1 to 3 carbon atoms is represented by -C (CH ₃ ) ₂ Is preferable, and the halogenated aliphatic hydrocarbon group having 1 to 3 carbon atoms is -C (CF ₃ ) ₂ -Is preferred. In the siloxane diamine represented by the general formula (2), R ¹ Is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, ² Is preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms.
[0035]
Examples of the aromatic diamine represented by the general formula (1) include 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and bis [4- (3-aminophenoxy) phenyl ] Sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, bis [4- (4-aminophenoxy) phenyl] methane , 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ketone, 1,3-bis (4 -Aminophenoxy) benzene and 1,4-bis (aminophenoxy) benzene.
[0036]
As the aromatic diamine, a compound represented by the following general formula (4) is preferably used, and BAPP is more preferably used. In the formula, Y has the same meaning as described above.
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[0037]
As the siloxane diamine represented by the general formula (2), it is preferable to use a dimethylsiloxane-based terminal amine. Such a compound is an amino-modified silicone oil X-22-161AS (amine equivalent 450), X-22-161A. (Amine equivalent 840), X-22-161B (amine equivalent 1500) (all made by Shin-Etsu Chemical Co., Ltd.), BY16-853 (amine equivalent 650), BY-16-853B (amine equivalent 2200) (more than Toray Dow) (Corning Silicone Co., Ltd.). These can be used alone or in combination.
[0038]
By reacting a mixture of the above aromatic diamine and siloxane diamine with trimellitic anhydride, diimidedicarboxylic acid can be obtained. The obtained diimide dicarboxylic acid includes compounds represented by the following general formulas (5a) and (5b).
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[0039]
In the formula, Z is a residue of the compound represented by the general formula (1) except for the amino group, ¹ , R ² And n are as defined above.
[0040]
In the reaction of a diamine mixture containing an aromatic diamine and a siloxane diamine with trimellitic anhydride, the number of moles of the aromatic diamine is A, the number of moles of the siloxane diamine is B, and the number of moles of trimellitic anhydride is C. The reaction is preferably performed such that the value of (A + B) / C becomes 1.0 / 2.0 to 1.0 / 2.2. The mixing ratio A / B of A and B is preferably from 99.9 / 0.1 to 0/100, and the mixing ratio is preferably determined according to the amine equivalent of B. For example, when the amine equivalent of siloxane diamine is 400-500, A / B is 99.9 / 0.1-0 / 100, and when the amine equivalent is 800-1000, A / B is 99.9 / 0.1. When the amine equivalent is 1500 to 1600, the A / B is preferably 99.9 / 0.1 to 60/40. By setting A, B, and C within the above ranges, the diimide dicarboxylic acids represented by the general formulas (5a) and (5b) are more easily generated, and the total amide group amount and total silicon in the generated polyamideimide The amount makes it easier to provide the above formulas (I) and (II).
[0041]
The diimide dicarboxylic acid is obtained by first reacting a diamine mixture containing an aromatic diamine and a siloxane diamine with trimellitic anhydride in an aprotic polar solvent at 50 to 90 ° C., and then forming an aromatic carbon distillable with water. It is preferable to produce by adding hydrogen and further reacting at 120 to 180 ° C. to cause a dehydration ring closure reaction. Examples of the aprotic polar solvent include dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, 4-butyrolactone, sulfolane and the like, and it is more preferable to use N-methyl-2-pyrrolidone.
[0042]
Examples of aromatic hydrocarbons that can be azeotroped with water include toluene, benzene, xylene, and ethylbenzene, and it is preferable to use toluene. It is preferable to add such an aromatic hydrocarbon in a weight ratio of 0.1 to 0.5 with respect to the aprotic polar solvent. Then, after the completion of the dehydration ring closure reaction, it is preferable to further raise the temperature to about 190 ° C. to remove aromatic hydrocarbons azeotropic with water.
[0043]
By reacting an aromatic diisocyanate with the diimide dicarboxylic acid obtained by the above reaction, a polyamide imide can be obtained.
[0044]
As the aromatic diisocyanate, a compound represented by the following general formula (6) can be used.
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[0045]
Wherein W is a divalent organic group having at least one aromatic ring; ₆ H ₄ -CH ₂ -C ₆ H ₄ It is preferably at least one group selected from the group consisting of a group represented by-, a tolylene group and a naphthylene group.
[0046]
Examples of the compound represented by the general formula (6) include 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, , 4-tolylene dimer and the like.
[0047]
The resulting polyamideimide is a compound having a repeating unit represented by the following general formula (7a) and the following general formula (7b). Such repeating units may be bonded in blocks or may be randomly bonded. In the formula, Z, W, R ¹ , R ² And n are as defined above.
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[0048]
The reaction between the diimide dicarboxylic acid and the aromatic diisocyanate is carried out by removing the aromatic hydrocarbon which can be azeotroped with water, cooling the solution once to room temperature, adding the aromatic diisocyanate, and heating at about 190 ° C. for 2 hours. It is preferable to make the reaction to a certain extent. In such a reaction, the amount of the aromatic diisocyanate to be added is preferably from 1.0 to 1.5 equivalents, more preferably from 1.1 to 1.3 equivalents, per equivalent of the produced diimide dicarboxylic acid. When the amount of the aromatic diisocyanate is less than 1.0 equivalent, the flexibility of the obtained adhesive layer tends to decrease. Flexibility tends to decrease.
[0049]
As the amide-reactive compound, a thermosetting resin having a functional group that reacts with an amide group can be used. Examples of the thermosetting resin include a polyfunctional epoxy compound, a polyimide resin, an unsaturated polyester resin, a polyurethane resin, a bismaleimide resin, a triazine-bismaleimide resin, and a phenol resin, and it is preferable to use a polyfunctional epoxy compound. By using a polyfunctional epoxy compound as the amide-reactive compound, not only the heat resistance but also the mechanical and electrical properties of the obtained adhesive layer can be improved.
[0050]
As the polyfunctional epoxy compound, a polyfunctional epoxy compound having two or more epoxy groups is preferably used, and a polyfunctional epoxy compound having three or more epoxy groups is more preferably used.
[0051]
Examples of the polyfunctional epoxy compound having two or more epoxy groups include an epoxy resin obtained by reacting a polyhydric phenol such as bisphenol A, a novolak phenol resin, an orthocresol novolac phenol resin, and epichlorohydrin; 1,4-butane; Epoxy resin obtained by reacting a polyhydric alcohol such as a diol with epichlorohydrin; polyglycidyl ester obtained by reacting a polybasic acid such as phthalic acid and hexahydrophthalic acid with epichlorohydrin; amine, amide or heterocyclic nitrogen base N-glycidyl derivatives of compounds having the formula: alicyclic epoxy resin and the like.
[0052]
Examples of the polyfunctional epoxy compound having three or more glycidyl groups include ZX-1548-2 (manufactured by Toto Kasei Co., Ltd.), DER-331L (bisphenol A type epoxy resin manufactured by Dow Chemical Company), and YDCN-195 (manufactured by Toto Kasei Co., Ltd.) Cresol novolak type epoxy resin).
[0053]
The amount of the amide-reactive compound can be determined according to the number of functional groups that react with the amide group. When the amount is A% by weight, the amount of amide group in the amide-reactive compound is B% by weight, the amount of silicon in the polyamideimide is C% by weight, and the amount of silicon in the amide-reactive compound is D% by weight, It is determined so as to satisfy the formulas (I) and (II).
[0054]
When a polyfunctional epoxy compound is used as the amide-reactive compound, it is preferable to further add a polyfunctional epoxy compound curing agent, a curing accelerator and the like to the second curable resin. As the curing agent for the polyfunctional epoxy compound, a conventionally known curing agent can be used, and examples thereof include amines such as dicyandiamide, diaminodiphenylmethane, and guanylurea; imidazoles; hydroquinone, resorcinol, bisphenol A and halides thereof, and novolak Phenolic resins such as phenolic resins and resol-type phenolic resins; acid anhydrides such as phthalic anhydride, benzophenonetetracarboxylic dianhydride, and methylhymic acid; and a curing accelerator such as alkyl. Imidazoles such as group-substituted imidazole and benzimidazole;
[0055]
The amount of the curing agent can be determined according to the epoxy equivalent of the polyfunctional epoxy compound.For example, when an amine compound is used as the curing agent, the equivalent of the active hydrogen of the amine and the epoxy equivalent of the polyfunctional epoxy compound are used. Are blended so as to be equal. When a polyfunctional phenol or an acid anhydride is used as the curing agent, the compounding amount is such that the phenolic hydroxyl group or the carboxyl group is 0.6 to 1.2 equivalents relative to 1 equivalent of the polyfunctional epoxy compound. Is preferable. When a curing accelerator is used, the amount of the curing accelerator is preferably 0.001 to 10 parts by weight based on 100 parts by weight of the polyfunctional epoxy compound. When the blending amount of these curing agents or curing accelerators is less than the above range, the curing of the polyfunctional epoxy compound becomes insufficient, and the glass transition temperature after curing of the second curable resin tends to decrease, which is large. In such a case, the remaining curing agent or curing accelerator tends to lower the electrical properties of the second curable resin after curing.
[0056]
A filler, a coupling agent, a flame retardant, and the like can be further added to the second curable resin as long as the curing is not hindered.
[0057]
Next, a method for producing a prepreg with an adhesive layer according to the present invention will be described.
[0058]
The method for producing a prepreg with an adhesive layer according to the present invention comprises the steps of: laminating a second curable resin on a prepreg made of a first curable resin in a B-stage state in which reinforcing fibers are arranged; A method for producing a prepreg with an adhesive layer, comprising laminating a second curable resin on the prepreg while heating the prepreg and the second curable resin so that curing is not completed. is there.
[0059]
The second curable resin is laminated on the prepreg in a heated state by using a known heating means (hot air heating, infrared heating, heat compression bonding, etc.). It is necessary to perform heating so that curing of both of the conductive resins is not completed. The adhesive layer to be laminated on the prepreg, the second curable resin, preferably a film-like curable resin formed into a film so that curing is not completed, more preferably the reaction between polyamideimide and amide-reactive compound is not completed It is preferable to form a film-form polyamideimide-based curable resin which has been formed into a film in advance as described above, and to laminate them. Whether or not the curing and the reaction have been completed can be confirmed by a differential scanning calorimeter (DSC). If an exothermic peak is observed in the DSC when the metal-clad laminate is kept at the heating temperature at the time of production, the curing and the reaction are completed. Is not completed.
[0060]
The film-form curable resin is formed on a support by dissolving or dispersing in an organic solvent such as dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone, sulfolane, or cyclohexanone. It is preferable that the organic solvent is removed and then the organic solvent is removed. When the organic solvent is removed by heating, it is necessary to perform the reaction so that the reaction between the polyamideimide and the amide-reactive compound is not completed.
[0061]
Examples of the support include polyethylene terephthalate and aluminum foil, and those obtained by subjecting their surfaces to release treatment are more preferable. In particular, it is preferable to use polyethylene terephthalate having a thickness of 30 μm to 200 μm that has been subjected to a release treatment.
[0062]
As a method of laminating the film-like curable resin on the prepreg, for example, a method by roll lamination can be mentioned. That is, the film-form polyamide-imide-based curable resin is stacked so as to be in contact with the prepreg, and is passed through heated rolls while being pressurized to be laminated while heating. In such a method, since the temperature of the heated roll corresponds to the lamination temperature, the lamination temperature can be easily controlled. The lamination temperature can be determined according to the second curable resin to be used. For example, when a polyfunctional epoxy compound is used as the amide-reactive compound, the lamination temperature is preferably 150 ° C or lower, and is preferably 80 to 150 ° C. Is more preferable, and particularly preferably 100 to 130 ° C. When the lamination temperature exceeds 150 ° C., the adhesiveness tends to decrease when the obtained prepreg with an adhesive layer is applied to a metal-clad laminate. On the other hand, when the temperature is lower than 80 ° C., the adhesiveness between the adhesive layer and the prepreg tends to decrease.
[0063]
Next, a preferred embodiment of a configuration of a prepreg with an adhesive layer obtained by the method for producing a prepreg with an adhesive layer of the present invention will be described with reference to the drawings.
[0064]
FIG. 1 is a sectional view showing one embodiment of a prepreg with an adhesive layer of the present invention. The prepreg 1 with an adhesive layer shown in FIG. 1 includes a prepreg 2 and an adhesive layer 4 formed on the prepreg 2 and made of a second curable resin. Here, the first curable resin in the prepreg 2 and the second curable resin constituting the adhesive layer 4 may be the same or different, but are preferably different.
[0065]
In the prepreg 1 with the adhesive layer, the thickness of the prepreg 2 is preferably 20 to 250 μm. The thickness of the adhesive layer 4 is preferably 30 μm or less, more preferably 5 to 20 μm. By setting the thickness of the adhesive layer 4 to 30 μm or less, it is possible to significantly reduce the warpage generated when the prepreg 1 with the adhesive layer is used for a metal-clad laminate. And the elastic modulus after hardening of the adhesive layer 4 is preferably 500 to 2500 MPa, more preferably 800 to 1500 MPa. By setting the elastic modulus of the adhesive layer 4 after curing within the above range, the adhesiveness and heat resistance are further improved.
[0066]
Next, a preferred embodiment of a method for manufacturing a metal-clad laminate using a prepreg with an adhesive layer obtained by the method for manufacturing a prepreg with an adhesive layer of the present invention will be described with reference to FIG.
[0067]
The metal-clad laminate can be manufactured, for example, as follows. That is, a metal-clad laminate can be manufactured by laminating at least one metal foil and at least one prepreg so that the prepreg is in contact with at least one surface of the metal foil, and then applying heat and pressure. Then, at least one of the metal foils is a metal foil that has not been subjected to a surface roughening treatment, and the adhesive layer is arranged so as to be in contact with the metal foil as a prepreg that is heated and pressed adjacent to at least the metal foil. It is preferable to use a prepreg with an adhesive layer obtained by the method for producing a prepreg with an adhesive layer described above.
[0068]
FIG. 2A schematically shows a process of laminating two metal foils 22 that have not been subjected to surface roughening treatment, three prepregs 10 for forming a laminate, and two prepregs 1 with an adhesive layer. It is sectional drawing shown in FIG. In the same step, three laminated body forming prepregs 10 are laminated so as to be adjacent to each other, and the metal foil 22 is disposed on the upper and lower surfaces of the laminated laminated body forming prepreg 10 via the prepreg 1 with an adhesive layer. Are laminated. In this case, the adhesive layer 4 in the prepreg 1 with an adhesive layer is arranged so as to be in contact with the metal foil 22.
[0069]
As the metal foil 22, a metal foil such as a copper foil or an aluminum foil can be used, and the thickness is preferably 5 to 200 μm. Further, between a copper foil layer having a thickness of 0.5 to 15 μm and a copper foil layer having a thickness of 10 to 300 μm, nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. A composite foil having a three-layer structure provided with an intermediate layer made of aluminum and a composite foil having a two-layer structure obtained by combining aluminum and copper foil can also be used. The surface roughness of the metal foil 22 is preferably Rz = 5 μm or less, more preferably Rz = 2 μm or less. Note that Rz refers to a ten-point average roughness specified in JIS B0601.
[0070]
After the lamination is completed as described above, the whole is heated and pressed to obtain a metal-clad laminate. FIG. 2B is a cross-sectional view schematically illustrating the obtained metal-clad laminate 30. The metal-clad laminate 30 shown in FIG. 1 has a prepreg 1 having an adhesive layer on its upper and lower surfaces with three layers of a cured prepreg 20 for forming a laminate being a cured product of the prepreg 10 for forming a laminate. (Comprised of the prepreg cured product 12 and the adhesive layer cured product 14) and the metal foil 22 are laminated in this order.
[0071]
In addition, lamination and hardening can be performed using a vacuum press or the like, and the temperature at the time of hardening is preferably 150 to 280 ° C, and more preferably 180 to 250 ° C. Further, the pressure is preferably 0.5 to 20 MPa, and more preferably 1 to 8 MPa.
[0072]
In the metal-clad laminate 30, the metal foil 22 is bonded to the prepreg cured product 12 via the adhesive layer cured product 14, and the prepreg cured product 12 and the prepreg cured product 20 for forming a laminate are integrated and laminated by curing. Since the metal foil 22 is formed, the metal foil 22 is firmly adhered to the laminate in the metal-clad laminate 30, and even when a fine wiring pattern is formed on the metal-clad laminate 30, The occurrence of peeling of the conductor layer made of 22 is extremely reduced. Further, since the cured adhesive layer 14 is a cured product of the adhesive layer 4 in the prepreg 1 with an adhesive layer according to the present invention, it has high heat resistance, and has a property such as blistering when exposed to high temperatures. The occurrence is greatly reduced.
[0073]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
[0074]
[Synthesis of Polyamideimide]
(Synthesis example 1)
A 2-mL bis-2- [4- (4-aminophenoxy) phenyl] as an aromatic diamine was placed in a 1-L separable flask equipped with a faucet connected to a reflux condenser with a 25-mL water content receiver, a thermometer, and a stirrer. 43.1 g (0.105 mol) of propane (BAPP), 40.1 g (0.045 mol) of reactive silicon oil KF8010 (manufactured by Shin-Etsu Chemical Co., Ltd., amine equivalent 445) as siloxane diamine, 60.5 g of trimellitic anhydride (TMA) (0.315 mol) and 440 g of N-methyl-2-pyrrolidone (NMP) as an aprotic polar solvent were added and stirred at 80 ° C. for 30 minutes.
[0075]
After completion of the stirring, 100 mL of toluene was added as an aromatic hydrocarbon azeotropic with water, the temperature was raised to 160 ° C., and the mixture was refluxed for 2 hours. After confirming that about 5.4 mL of water has accumulated in the moisture quantification receiver and that no more water has been distilled off, the temperature is increased to 190 ° C. while removing water from the moisture quantification receiver, and toluene is removed. Was removed.
[0076]
After the solution in the flask was returned to room temperature, 45.1 g (0.18 mol) of 4,4′-diphenylmethane diisocyanate (MDI) was added as an aromatic diisocyanate, the temperature was increased to 190 ° C., and the reaction was carried out for 2 hours. An NMP solution of polyamideimide having an amount of 8.1% by weight and a silicon amount of 6.9% by weight was obtained.
[0077]
(Synthesis example 2)
41.1 g (0.10 mol) of BAPP as an aromatic diamine and reactive silicon oil as a siloxane diamine were placed in a 1 L separable flask equipped with a 25 mL water content receiver with a cock connected to a reflux condenser, a thermometer and a stirrer. 90.0 g (0.10 mol) of KF8010, 80.7 g (0.42 mol) of TMA, and 505 g of NMP as an aprotic polar solvent were added, and the mixture was stirred at 80 ° C. for 30 minutes.
[0078]
After completion of the stirring, 100 mL of toluene was added as an aromatic hydrocarbon azeotropic with water, the temperature was raised to 160 ° C., and the mixture was refluxed for 2 hours. After confirming that about 7.2 mL or more of water has accumulated in the moisture quantification receiver and that no distilling of water has been observed, the temperature was increased to 190 ° C. while removing water from the moisture quantification receiver, and toluene was removed. Was removed.
[0079]
After the solution in the flask was returned to room temperature, 60.1 g (0.24 mol) of MDI was added as an aromatic diisocyanate, the temperature was increased to 190 ° C., and the reaction was carried out for 2 hours. The amount of the amide group was 7.4% by weight and the amount of silicon was 10%. A 9.9% by weight polyamideimide NMP solution was obtained.
[0080]
(Synthesis example 3)
55.4 g (0.135 mol) of BAPP as an aromatic diamine and a reactive silicone oil as a siloxane diamine were placed in a 1-L separable flask equipped with a faucet connected to a reflux condenser with a 25-mL water content receiver, a thermometer and a stirrer. X-22-161B (manufactured by Shin-Etsu Chemical Co., Ltd., amine equivalent: 1560) 46.8 g (0.015 mol), 60.5 g (0.315 mol) of TMA, and 485 g of NMP as an aprotic polar solvent were added and stirred at 80 ° C. for 30 minutes. did.
[0081]
After completion of the stirring, 100 mL of toluene was added as an aromatic hydrocarbon azeotropic with water, the temperature was raised to 160 ° C., and the mixture was refluxed for 2 hours. After confirming that about 5.4 mL of water has accumulated in the moisture quantification receiver and that no more water has been distilled off, the temperature is increased to 190 ° C. while removing water from the moisture quantification receiver, and toluene is removed. Was removed.
[0082]
After the solution in the flask was returned to room temperature, 45.1 g (0.18 mol) of MDI was added as an aromatic diisocyanate, the temperature was increased to 190 ° C., and the reaction was carried out for 2 hours. The amount of the amide group was 7.2% by weight and the amount of silicon was 9%. A 0.0% by weight NMP solution of polyamideimide was obtained.
[0083]
[Preparation of second curable resin]
(Preparation Example 1)
300 g (solid content: 30% by weight) of NMP solution of polyamideimide obtained in Synthesis Example 1, 20 g of ZX-1548-2 (manufactured by Toto Kasei Co., Ltd., phosphorus-containing polyfunctional epoxy resin) as an amide reactive compound ( A resin solid content of 50% by weight in dimethylacetamide solution) and 0.2 g of 2-ethyl-4-methylimidazole were mixed, and the mixture was stirred for about 1 hour until the composition became homogeneous, and then left at room temperature for 24 hours for defoaming. Then, a varnish of a second curable resin having a total amide group content of 7.3% by weight and a total silicon amount of 6.3% by weight was obtained.
[0084]
(Preparation Example 2)
267 g of an NMP solution of the polyamideimide obtained in Synthesis Example 1 (solid content 30% by weight), 40 g of an epoxy resin ZX-1548-2 as an amide reactive compound (resin solid content of 50% by weight in dimethylacetamide solution), 0.2 g of 2-ethyl-4-methylimidazole was blended, and the mixture was stirred for about 1 hour until the resin composition became uniform. Then, the mixture was allowed to stand at room temperature for 24 hours for defoaming, and the total amount of amide groups was 6.4. By weight, a varnish of a second curable resin having a total silicon content of 5.6% by weight was obtained.
[0085]
(Preparation Example 3)
300 g of NMP solution of polyamideimide obtained in Synthesis Example 1 (solid content 30% by weight), DER-331L which is an epoxy resin as an amide reactive compound (Dow Chemical Co., Ltd., bisphenol A type epoxy resin), 20 g (resin solid content) 50% by weight of dimethylacetamide solution) and 0.2 g of 2-ethyl-4-methylimidazole, and the mixture was stirred for about 1 hour until the resin composition became homogeneous, and then left at room temperature for 24 hours for defoaming. Thus, a varnish of a second curable resin having a total amide group content of 7.3% by weight and a total silicon amount of 6.3% by weight was obtained.
[0086]
(Preparation Example 4)
300 g (solid content: 30% by weight) of an NMP solution of the polyamideimide obtained in Synthesis Example 1, 20 g of a YDCN-195 (Cresol novolac type epoxy resin manufactured by Toto Kasei Co., Ltd.) which is an epoxy resin as an amide-reactive compound (resin solid content) 50% by weight of dimethylacetamide solution) and 0.2 g of 2-ethyl-4-methylimidazole, and the mixture was stirred for about 1 hour until the resin composition became homogeneous, and then left at room temperature for 24 hours for defoaming. Thus, a varnish of a second curable resin having a total amide group content of 7.3% by weight and a total silicon amount of 6.3% by weight was obtained.
[0087]
(Preparation Example 5)
300 g (solid content: 35% by weight) of an NMP solution of the polyamideimide obtained in Synthesis Example 2, 20 g of an epoxy resin ZX-1548-2 as a amide reactive compound (a dimethylacetamide solution having a resin solid content of 50% by weight), After mixing 0.3 g of 2-ethyl-4-methylimidazole and stirring for about 1 hour until the resin composition becomes uniform, the mixture was allowed to stand at room temperature for 24 hours for defoaming, and the total amount of amide groups was 6.5. By weight, a varnish of a second curable resin having a total silicon content of 9.8% by weight was obtained.
[0088]
(Preparation Example 6)
300 g of an NMP solution of the polyamideimide obtained in Synthesis Example 3 (solid content: 30% by weight), 20 g of an epoxy resin ZX-1548-2 as an amide reactive compound (a dimethylacetamide solution having a resin solid content of 50% by weight), 0.3 g of 2-ethyl-4-methylimidazole was added, and the mixture was stirred for about 1 hour until the resin composition became uniform. By weight, a varnish of a second curable resin having a total silicon content of 8.1% by weight was obtained.
[0089]
[Preparation of prepreg with adhesive layer]
(Example 1)
The second curable resin varnish obtained in Preparation Example 1 was applied to a 50 μm-thick polyethylene terephthalate film (PET film, Purex, manufactured by Teijin Limited) so that the adhesive layer after drying had a thickness of 15 μm. And dried by heating at 130 ° C. for 20 minutes to obtain a film with an adhesive containing 5 to 7% by weight of a volatile component.
[0090]
Next, the obtained film with an adhesive layer is overlaid on a prepreg (GEA-I-671, manufactured by Hitachi Chemical Co., Ltd.) so that the adhesive layer is in contact with the film. After laminating with a hot roll laminator under the condition of 2 m / min, the PET film was peeled off to obtain a prepreg with an adhesive layer of Example 1 in which an adhesive layer was formed on the prepreg.
[0091]
(Examples 2 to 6)
Examples 2 to 6 were carried out in the same manner as in Example 1 except that the varnish of the second curable resin of Preparation Examples 2 to 6 was used instead of the varnish of the second curable resin obtained in Preparation Example 1. A prepreg with an adhesive layer was obtained. In addition, the case of using the varnish of the second curable resin of Preparation Examples 2 to 6 corresponds to Examples 2 to 6, respectively.
[0092]
(Comparative Example 1)
A prepreg with an adhesive layer was produced in the same manner as in Example 1 except that lamination was performed at 160 ° C., 180 ° C., and 28 ° C. instead of the hot roll temperature of 120 ° C. However, when laminating at a hot roll temperature of 180 ° C., it is impossible to peel off the PET film from the adhesive layer, and when performing at 28 ° C., adhesion between the film with the adhesive layer and the prepreg is not possible. Was impossible. Therefore, a prepreg with an adhesive layer at a hot roll temperature of 160 ° C. was subjected to a test as Comparative Example 1.
[0093]
(Examples 7 to 11)
Same as Example 1 except that the varnish of the second curable resin obtained in Preparation Example 1 was applied so that the dried thickness of the adhesive layer was 5, 10, 20, 30, and 50 μm. Thus, prepregs of Examples 7 to 11 were obtained. The thickness of the adhesive layer after drying of 5, 10, 20, 30, and 50 μm corresponds to Examples 7, 8, 9, 10, and 11, respectively.
[0094]
[Measurement of adhesive strength, solder heat resistance and elastic modulus]
After the prepregs with adhesive layers of Examples 1 to 6 and Comparative Example 1 were respectively laminated so that the prepregs were in contact with both surfaces of a laminate in which three prepregs (GEA-I-671) were laminated, the outermost layer was formed. Glossy surface (Rz = 2.10) of F0-WS-12 (Furukawa Electric Co., Ltd., Rz = 1.8 μm) and SLP-12 (Nippon Denshi Co., Ltd.) as copper foils having different surface roughnesses on both adhesive layers. 0 μm) or GTS-12 (Furukawa Circuit Foil Co., Ltd., Rz = 8.0 μm), and pressed using a vacuum press at 230 ° C. for 90 minutes at 4.0 MPa. Got.
[0095]
The adhesive strength was measured by measuring the peel strength (90 ° peel strength, based on JIS C 6481) when the copper foil in each of the obtained metal-clad laminates was peeled in the direction of 90 °. went.
[0096]
Next, the above-mentioned metal-clad laminate obtained by using the copper foil of Rz = 1.8 μm was cut into a size of 20 mm × 20 mm to obtain a sample for a soldering heat resistance test. Each of them was immersed in a solder bath, and it was visually confirmed whether blisters or peeling of the metal foil had occurred, and the solder heat resistance was evaluated. The evaluation of the solder heat resistance was performed by measuring the time from immersion of the sample in the solder bath to the occurrence of blistering or peeling of the metal foil, and taking the obtained time as a measured value.
[0097]
Further, in order to make a comparison with the case where a prepreg having no adhesive layer was used, as Reference Example 1, five sheets of prepreg (GEA-I-671) were laminated on both surfaces of a laminate, and Rz = 1. 8 μm copper foil was laminated, pressed at 230 ° C. for 90 minutes using a vacuum press at 4.0 MPa, and the adhesive strength and solder heat resistance were measured using a metal-clad laminate in the same manner as described above. .
[0098]
Further, the following test was performed to measure the elastic modulus of the adhesive layer after curing. First, each of the second curable resin varnishes obtained in Preparation Examples 1 to 6 was applied to a polyethylene terephthalate film (PET film) having a thickness of 50 μm so that the thickness after drying became 80 μm, The mixture was heated for a minute to evaporate the solvent and harden. After curing, the PET film is peeled off to obtain a cured product of the second curable resin. The cured product of the second curable resin is sandwiched between SUS frames, and further heated at 230 ° C. for 90 minutes. Was performed to obtain a film-like curable resin having a thickness of 80 μm. Then, the elastic modulus at 30 ° C. of the obtained film-shaped curable resin was measured using a dynamic viscoelasticity measuring device (manufactured by Rheology).
[0099]
Table 1 also shows the results obtained by the measurement of the adhesive strength and the solder heat resistance. The measurement results of the elastic modulus are described in the column of prepreg using the same second curable resin varnish.
[Table 1]

As shown in Table 1, in the metal-clad laminate using the prepreg with the adhesive layer of Examples 1 to 6, the copper foil having any surface roughness has a surface roughness of 0.8 to 1.4 kN / m. The adhesive strength was shown, and no abnormality such as blistering or peeling of the metal foil was observed for 3 minutes or more when immersed in a solder bath at any temperature. The metal-clad laminate using the prepreg and Reference Example 1 exhibited an adhesive strength of 0.2 to 0.6 kN / m. In addition, blistering or peeling of the metal foil was observed within 20 seconds after immersion in the solder bath. Was done.
[0100]
[Evaluation of influence by thickness of adhesive layer]
The prepregs with an adhesive layer of Examples 7 to 11 were laminated on one surface of a laminate in which three prepregs were laminated such that the adhesive layers were in contact with each other. -12 (Rz = 1.8 μm) or a glossy surface (Rz = 2.0 μm) of SLP-12 is laminated and pressed by using a vacuum press at 230 ° C. for 90 minutes at 4.0 MPa. A laminated laminate was obtained.
[0101]
Using each of the obtained metal-clad laminates, the occurrence of warpage was confirmed and the adhesive strength was measured. The occurrence of warpage was visually checked to determine whether the metal-clad laminate had warped, and the adhesive strength was measured in the same manner as described above.
[0102]
Table 2 summarizes the results of the confirmation of the occurrence of warpage and the measurement of the adhesive strength. In Table 2, the case where no warpage was observed was indicated by ○, and the case where warpage was observed was indicated by ×.
[Table 2]

[0103]
As shown in Table 2, the metal-clad laminate using any prepreg with an adhesive layer showed an adhesive strength of 0.6 to 1.1 kN / m, but the thickness of the adhesive layer was 50 μm. The surface of the metal-clad laminate using the prepreg with the adhesive layer was warped so that the copper foil was on the inside.
[0104]
[Evaluation of circuit formability]
After the prepregs with the adhesive layers of Examples 1 and 6 were laminated on both sides of a laminate in which four prepregs were laminated such that the prepregs were in contact with each other, SLP-100 (Nihon Denkisha) was added to one of the adhesive layers. ), And copper foils (Rz = 1.8 μm, Rz = 2.0 μm, or Rz = 8.0 μm) having different surface roughnesses are respectively laminated on the other adhesive layer, and 230 The metal-clad laminate was obtained by pressing at 4.0 ° C. for 90 minutes at 4.0 ° C.
[0105]
Using each of the obtained metal-clad laminates, a resist is entirely formed on the surface of the SLP-100 present on one surface of the metal-clad laminate, and on a copper foil having a different surface roughness on the other surface. Then, a comb-shaped resist pattern having a line width / space width (L / S) of 20 μm / 20 μm, 30 μm / 30 μm, 40 μm / 40 μm, or 50 μm / 50 μm was formed, respectively. Then, after the unprotected copper foil was removed by etching using a ferric chloride solution, the resist was peeled off to form a wiring pattern.
[0106]
The evaluation of the circuit formability of the metal-clad laminate on which the wiring pattern was formed was performed using a microscope, and the evaluation was performed by determining the minimum value of line width / space width (L / S) at which circuit formation was possible. Sex value.
[0107]
In addition, in order to make a comparison with a case where a prepreg having no adhesive layer was used, as a reference example 2, five sheets of prepreg (GEA-I-671) were laminated on both surfaces in the same manner as described above. Using a metal-clad laminate obtained by laminating copper foils, circuit formability was evaluated in the same manner as described above.
[0108]
Table 3 summarizes the evaluation results of the obtained circuit formability.
[Table 3]

[0109]
As shown in Table 3, in the metal-clad laminate using the prepreg with the adhesive layer of Example 1 or 6, a copper foil having a relatively smooth metal foil surface (Rz = 1.8 μm or 2.0 μm) was used. Even with the metal-clad laminate used, the removal of residual copper during etching can be performed in a short time, and a favorable wiring pattern having a line width / space width = 20 μm / 20 μm and a cross-sectional shape close to a rectangle is obtained. Was. On the other hand, in Reference Example 2, when the copper foil of Rz = 1.8 μm or 2.0 μm was used, the copper foil was partially peeled. In the case of using a copper foil with Rz = 8.0 μm, no peeling occurred in any of the metal-clad laminates. However, it took a long time to remove residual copper on the copper foil surface during etching. Tended to have a thin Kamaboko shape at the top. For this reason, the line width / space width of 40 μm / 40 μm was the limit for obtaining a good wiring pattern.
[0110]
【The invention's effect】
As described above, according to the prepreg with an adhesive layer of the present invention, in the production of a metal-clad laminate, even when a conductor layer having a smooth surface that has not been subjected to surface roughening treatment is used, it is laminated with the conductor layer. It is possible to provide a method for producing a prepreg with an adhesive layer, which can improve the adhesion to the body and can reduce the occurrence of blisters under high temperature conditions.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one embodiment of a prepreg with an adhesive layer.
FIG. 2 (a) shows a process of laminating two metal foils 22 not subjected to surface roughening treatment, three prepregs 10 for forming a laminate, and two prepregs 1 with an adhesive layer. It is sectional drawing which shows typically, (b) is sectional drawing which shows the obtained metal-clad laminated board 40 typically.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Prepreg with an adhesive layer, 2 ... Prepreg, 4 ... Adhesive layer, 10 ... Prepreg for forming a laminate, 12 ... Cured prepreg, 14 ... Hardened adhesive layer Product, 20: cured prepreg for forming a laminate, 22: metal foil, 30: metal-clad laminate.

Claims (7)

A method for producing a prepreg with an adhesive layer, comprising: laminating a second curable resin on a prepreg made of a first curable resin in a B-stage state in which reinforcing fibers are arranged to form an adhesive layer;
A method comprising laminating the second curable resin on the prepreg while heating the prepreg and the second curable resin so that curing is not completed. The second curable resin is a polyamideimide-based curable resin including a polyamideimide having a siloxane structure in a main chain and an amide-reactive compound having a functional group that reacts with an amide group of the polyamideimide. ,
The polyamide-imide curable resin is laminated on the prepreg while heating the prepreg and the polyamide-imide curable resin so that the curing of the prepreg and the reaction are not completed. Of producing a prepreg with an adhesive layer. The polyamide-imide-based curable resin laminated on the prepreg is a film-shaped polyamide-imide-based curable resin obtained by molding the polyamide-imide-based curable resin into a film so that the reaction is not completed. A method for producing a prepreg with an adhesive layer according to claim 2. The polyamide imide,
A diimide dicarboxylic acid obtained by reacting an aromatic diamine represented by the following general formula (1) and a diamine mixture containing a siloxane diamine represented by the following general formula (2) with trimellitic anhydride:
4. The method for producing a prepreg with an adhesive layer according to claim 2, wherein the prepreg is a polyamide imide obtained by reacting an aromatic diisocyanate.

[Wherein X is a divalent group represented by the following general formula (3a) or (3b), R ¹ is an alkyl group, a phenyl group or a substituted phenyl group, R ² is an alkylene group, a phenylene group or a substituted phenylene group. , N represents an integer of 1 to 15.

However, Y is an aliphatic hydrocarbon group having 1 to 3 carbon atoms, a halogenated aliphatic hydrocarbon group having 1 to 3 carbon atoms, a sulfonyl group, an ether group, a carbonyl group or a single bond, R ¹ there are a plurality of and each R ² may be the same or different. ] The method for producing a prepreg with an adhesive layer according to any one of claims 2 to 4, wherein the amide-reactive compound is a polyfunctional epoxy compound having two or more epoxy groups. The method for producing a prepreg with an adhesive layer according to any one of claims 1 to 5, wherein the heating is performed at 80 to 150 ° C. A prepreg with an adhesive layer, which is obtained by the method for producing a prepreg with an adhesive layer according to any one of claims 1 to 6.

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