JP2004277671A - Prepreg and printed circuit board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prepreg excellent in dielectric property, laser-processing property and flame retardant property, and a printed circuit board. <P>SOLUTION: The prepreg is obtained by impregnating a resin composition containing a cyanate resin and/or its prepolymer and an inorganic filler with a nonwoven fabric constituted by an organic fiber, and exhibits ≤50 ppm/°C thermal expansion coefficient in surface direction at or lower than a glass transition point of a cured material obtained by curing the prepreg. Also, the printed circuit board is obtained by laminating a metal foil on the prepreg and heating/compressing for forming. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

前記式（Ｉ）で示されるノボラック型シアネート樹脂のｎは、特に限定されないが、１〜１０が好ましく、特に１〜７が好ましい。これより少ないとノボラック型シアネート樹脂は結晶化しやすくなり、汎用溶媒に対する溶解性が比較的低下するため、取り扱いが困難となる場合がある。また、これより多いと架橋密度が高くなりすぎ、耐水性の低下や、硬化物が脆くなるなどの現象を生じる場合がある。
【００１２】
前記シアネート樹脂および／またはそのプレポリマーの重量平均分子量は、特に限定されないが、重量平均分子量５００〜４，５００が好ましく、特に６００〜３，０００が好ましい。重量平均分子量が前記下限値未満であるとプリプレグを作製した場合にタック性が生じ、プリプレグ同士が接触したとき互いに付着したり、樹脂の転写が生じたりする場合がある。また、前記上現値を超えると反応が速くなりすぎ、プリント配線板とした場合に、成形不良を生じたり、層間ピール強度が低下したりする場合がある。
【００１３】
前記シアネート樹脂の含有量は、特に限定されないが、樹脂組成物全体の５〜６０重量％が好ましく、特に１０〜５０重量％が好ましい。含有量が前記下限値未満であると耐熱性や低熱膨張化する効果が低下する場合があり、前記上限値を超えると架橋密度が高くなり自由体積が増えるため耐湿性が低下する場合がある。
【００１４】
本発明のプリプレグでは、特に限定されないが、エポキシ樹脂を用いることが好ましい。前記エポキシ樹脂としては、例えばフェノールノボラック型エポキシ樹脂、ビスフェノール型エポキシ樹脂、ナフタレン型エポキシ樹脂、アリールアルキレン型エポキシ樹脂等が挙げられる。これらの中でもアリールアルキレン型エポキシ樹脂が好ましい。これにより、吸湿半田耐熱性を向上させることができる。
【００１５】
前記アリールアルキレン型エポキシ樹脂とは、繰り返し単位中に一つ以上のアリールアルキレン基を有するエポキシ樹脂をいう。例えばキシリレン型エポキシ樹脂、ビフェニルジメチレン型エポキシ樹脂等が挙げられる。これらの中でもビフェニルジメチレン型エポキシ樹脂が好ましい。ビフェニルジメチレン型エポキシ樹脂は、例えば式（ＩＩ）で示すことができる。
【化２】

前記式（ＩＩ）で示されるビフェニルジメチレン型エポキシ樹脂のｎは、特に限定されないが、１〜１０が好ましく、特に２〜５が好ましい。これより少ないとビフェニルジメチレン型エポキシ樹脂は結晶化しやすくなり、汎用溶媒に対する溶解性が比較的低下するため、取り扱いが困難となる場合がある。また、これより多いと樹脂の流動性が低下し、成形不良等の原因となる場合がある。
【００１６】
更に、前述のシアネート樹脂および／またはそのプレポリマー（特にノボラック型シアネート樹脂）とフェノール樹脂とアリールアルキレン型エポキシ樹脂（特にビフェニルジメチレン型エポキシ樹脂）との組合せを用いてプリント配線板を作製した場合、特に優れた寸法安定性を得ることが出来る。
【００１７】
前記エポキシ樹脂の含有量は、特に限定されないが、樹脂組成物全体の１〜５５重量％が好ましく、特に２〜４０重量％が好ましい。含有量が前記下限値未満であるとシアネート樹脂の反応性が低下したり、得られる製品の耐湿性が低下したり場合があり、前記上限値を超えると耐熱性が低下する場合がある。
【００１８】
前記エポキシ樹脂の重量平均分子量は、特に限定されないが、重量平均分子量５００〜２０，０００が好ましく、特に８００〜１５，０００が好ましい。重量平均分子量が前記下限値未満であるとプリプレグにタック性が生じる場合が有り、前記上限値を超えるとプリプレグ作製時、基材への含浸性が低下し、均一な製品が得られない場合がある。
【００１９】
本発明のプリプレグでは、特に限定されないが、フェノール樹脂を用いることが好ましい。前記フェノール樹脂としては、例えば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、アリールアルキレン型フェノール樹脂等が挙げられる。これらの中でもアリールアルキレン型フェノール樹脂が好ましい。これにより、さらに吸湿半田耐熱性を向上させることができる。
【００２０】
前記アリールアルキレン型フェノール樹脂としては、例えばキシリレン型フェノール樹脂、ビフェニルジメチレン型フェノール樹脂等が挙げられる。ビフェニルジメチレン型フェノール樹脂は、例えば式（ＩＩＩ）で示すことができる。
【化３】

前記式（ＩＩＩ）で示されるビフェニルジメチレン型フェノール樹脂のｎは、特に限定されないが、１〜１２が好ましく、特に２〜８が好ましい。これより少ないと耐熱性が低下する場合がある。また、これより多いと他の樹脂との相溶性が低下し、作業性が悪くなる場合があるため好ましくない。
【００２１】
前述のシアネート樹脂および／またはそのプレポリマー（特にノボラック型シアネート樹脂）とアリールアルキレン型フェノール樹脂との組合せにより、架橋密度をコントロールし、金属と樹脂との密着性を向上することができる。
【００２２】
前記フェノール樹脂の含有量は、特に限定されないが、樹脂組成物全体の１〜５５重量％が好ましく、特に５〜４０重量％が好ましい。含有量が前記下限値未満であると耐熱性が低下する場合があり、前記上限値を超えると低熱膨張の特性が損なわれる場合がある。
【００２３】
前記フェノール樹脂の重量平均分子量は、特に限定されないが、重量平均分子量４００〜１８，０００が好ましく、特に５００〜１５，０００が好ましい。重量平均分子量が前記下限値未満であるとプリプレグにタック性が生じる場合が有り、前記上限値を超えるとプリプレグ作製時、基材への含浸性が低下し、均一な製品が得られない場合がある。
【００２４】
本発明のプリプレグでは、無機充填材を用いる。これにより、低熱膨張化および難燃性の向上が図れる。
また、前述したシアネート樹脂および／またはそのプレポリマー（特にノボラック型シアネート樹脂）と無機充填材との組合せにより、特にプリント配線板の弾性率を向上させることができる。
前記無機充填材としては、例えばタルク、アルミナ、ガラス、シリカ、マイカ等を挙げることができる。これらの中でもシリカが好ましく、溶融シリカ（特に球状溶融シリカ）が低熱膨張性に優れる点で好ましい。その形状は破砕状、球状があるが、ガラス基材への含浸性を確保するために樹脂組成物の溶融粘度を下げるには球状シリカを使うなど、その目的にあわせた使用方法が採用される。
【００２５】
前記無機充填材の平均粒径は、特に限定されないが、０．０１〜５．０μｍが好ましく、特に０．２〜２．０μｍが好ましい。無機充填材の粒径が前記下限値未満であるとワニスの粘度が高くなるため、プリプレグ作製時の作業性に影響を与える場合がある。また、前記上限値を超えると、ワニス中で無機充填剤の沈降等の現象が起こる場合がある。
【００２６】
更に平均粒径５．０μｍ以下の球状シリカ（特に球状溶融シリカ）が好ましく、特に平均粒径０．０１〜２．０μｍの球状溶融シリカが好ましい。これにより、無機充填剤の充填性を向上させることができる。
【００２７】
前記無機充填材の含有量は、特に限定されないが、樹脂組成物全体の３０〜８０重量％が好ましく、特に４０〜７０重量％が好ましい。含有量が前記範囲内であると低熱膨張、低吸水とすることができる。
【００２８】
本発明のプリプレグでは、上記シアネート樹脂および／またはそのプレポリマー、エポキシ樹脂及びフェノール樹脂の一部をビニルエステル樹脂、メラミン樹脂等の他の熱硬化性樹脂、フェノキシ樹脂、ポリイミド樹脂、ポリアミドイミド樹脂、ポリフェニレンオキサイド樹脂、ポリエーテルスルホン樹脂等の熱可塑性樹脂と併用しても良い。
【００２９】
本発明のプリプレグでは、特に限定されないが、カップリング剤を用いることが好ましい。カップリング剤は樹脂と無機充填剤の界面の濡れ性を向上させることにより、基材に対して樹脂および充填剤を均一に定着させ、耐熱性、特に吸湿後の半田耐熱性を改良するために配合する。カップリング剤としては通常用いられるものなら何でも使用できるが、これらの中でもエポキシシランカップリング剤、チタネート系カップリング剤、アミノシランカップリング剤及びシリコーンオイル型カップリング剤の中から選ばれる１種以上のカップリング剤を使用することが無機充填剤界面との濡れ性が高く、耐熱性向上の点で好ましい。
【００３０】
本発明でカップリング剤の含有量は、特に限定されないが、無機充填剤全体に対して０．０５〜３重量部が好ましい。含有量が前記下限値未満であると充填剤を十分に被覆できず十分な耐熱性が得られない場合があり、前記上限値を超えると反応に影響を与え、曲げ強度等が低下する場合がある。
【００３１】
本発明のプリプレグでは、必要に応じて硬化促進剤を用いてもよい。硬化促進剤としては公知の物を用いることが出来る。たとえば、ナフテン酸亜鉛、ナフテン酸コバルト、オクチル酸スズ、オクチル酸コバルト、ビスアセチルアセトナートコバルト（ＩＩ）、トリスアセチルアセトナートコバルト（ＩＩＩ）等の有機金属塩、トリエチルアミン、トリブチルアミン、ジアザビシクロ［２，２，２］オクタン等の３級アミン類、２−フェニル−４−メチルイミダゾール、２−エチル−４−エチルイミダゾール、２−フェニル−４−メチルイミダゾール、２−フェニル−４−メチル−５−ヒドロキシイミダゾール、２−フェニル−４，５−ジヒドロキシイミダゾール等のイミダゾール類、フェノール、ビスフェノールＡ、ノニルフェノー等のフェノール化合物、酢酸、安息香酸、サリチル酸、パラトルエンスルホン酸等の有機酸等、またはこの混合物が挙げられる。
【００３２】
本発明のプリプレグでは、必要に応じて、上記成分以外の添加物を添加することが出来る。これらの各樹脂および各添加物で構成される樹脂組成物を、後述する有機繊維で構成される不織布に含浸する。
【００３３】
本発明のプリプレグでは、上述の樹脂組成物を有機繊維で構成される不織布に含浸する。
前記有機繊維を構成する樹脂としては、例えば芳香族ポリアミド樹脂、ポリアミド樹脂、芳香族ポリエステル樹脂、ポリエステル樹脂、ポリイミド樹脂、フッ素樹脂等が挙げられる。これらの中でも芳香族ポリエステル樹脂（特に全芳香族ポリエステル樹脂）、芳香族ポリアミド樹脂（特に全芳香族ポリアミド樹脂）から選ばれる１種以上の樹脂を主成分とすることが好ましい。これにより、プリプレグをプリント配線板としたときにレーザ加工性を向上させることができる。また、特に芳香族ポリエステル樹脂（全芳香族ポリエステル樹脂）が好ましい。これにより、プリプレグの電気特性（誘電特性）をより向上させることができる。
【００３４】
前記有機繊維を構成する樹脂のガラス転移点は、特に限定されないが、２００℃以上が好ましく、特に２５０〜４００℃が好ましい。ガラス転移点が前記下限値未満であるとフリップチップ実装性が低下する場合がある。
【００３５】
前記樹脂組成物を前記基材に含浸させる方法は、例えば基材を樹脂ワニスに浸漬する方法、各種コーターによる塗布する方法、スプレーによる吹き付ける方法等が挙げられる。これらの中でも、基材を樹脂ワニスに浸漬する方法が好ましい。これにより、基材に対する樹脂組成物の含浸性を向上させることができる。なお、基材を樹脂ワニスに浸漬する場合、通常の含浸塗布設備を使用することができる。
【００３６】
前記樹脂ワニスに用いられる溶媒は、前記樹脂組成物に対して良好な溶解性を示すことが望ましいが、悪影響を及ぼさない範囲で貧溶媒を使用しても構わない。良好な溶解性を示す溶媒としては、例えばアセトン、メチルエチルケトン、メチルイソブチルケトン、シクロペンタノン、シクロヘキサノン、ジメチルホルムアミド、ジメチルアセトアミド、Ｎ−メチルピロリドン等が挙げられる。
【００３７】
前記樹脂ワニスの固形分は、特に限定されないが、前記樹脂組成物の固形分３０〜８０重量％が好ましく、特に４０〜７０重量％が好ましい。これにより、樹脂ワニスの基材への含浸性を向上させることができる。
前記基材に前記樹脂組成物を含浸させ、所定温度、例えば９０〜１８０℃で乾燥させることによりプリプレグを得ることが出来る。
【００３８】
本発明のプリプレグは、上述のプリプレグを硬化して得られる硬化物のガラス転移点以下での面方向の熱膨張係数（α_１）が５０ｐｐｍ／℃以下である。すなわち、ガラス転移温度以下の領域（α_１領域）における硬化物のｘｙ方向の膨張率（α_１）を前記下限値未満とすることにより、半導体チップとの接続信頼性を向上させることができる。
例えば、銅の膨張率が１７ｐｐｍ／℃であることから、基板の面方向の線膨張係数が１７ｐｐｍ／℃付近になれば、銅と基板との間の熱膨張量の差が少なくなり応力は軽減する。よって、熱衝撃による半導体チップと基板との接続信頼性を向上させることができると考えられる。
【００３９】
また、前記硬化物の面方向の熱膨張張係数（α_１）は、１０〜３０ｐｐｍ／℃が好ましく、特に１５〜２０ｐｐｍ／℃が好ましい。熱膨張係数が上記範囲内であると、特に基板の接続信頼性に優れることができる。
前記面方向の熱膨脹率は、熱機械分析（ＴＭＡ）装置を用いて、ＪＩＳ Ｋ−７１９７に記載される方法にて測定することができる。その測定原理は、測定試料をステージにセットし、一定荷重の負荷をかけ、等速で昇温し、生じる膨張量を差動トランスで電気的出力として検出し、温度との関係を調べるものである。
また、ここで面方向とは、プリプレグの流れ方向（プリプレグの機械方向）を示す縦方向と、プリプレグの幅方向（プリプレグの反機械方向）を示す横方向を意味するものである。
【００４０】
次に、プリント配線板について説明する。
本発明のプリント配線板は、上記のプリプレグに金属箔を積層して加熱加圧成形してなるものである。これにより、耐熱性、低膨張性および難燃性に優れたプリント配線板を得ることができる。
プリプレグ１枚のときは、その上下両面もしくは片面に金属箔を重ねる。また、プリプレグを２枚以上積層することもできる。プリプレグ２枚以上積層するときは、積層したプリプレグの最も外側の上下両面もしくは片面に金属箔あるいはフィルムを重ねる。
【００４１】
次に、プリプレグと金属箔とを重ねたものを加熱加圧成形することでプリント配線板を得ることができる。前記加熱する温度は、特に限定されないが、１２０〜２２０℃が好ましく、特に１５０〜２００℃が好ましい。前記加圧する圧力は、特に限定されないが、１．５〜５ＭＰａが好ましく、特に２〜４ＭＰａが好ましい。また、必要に応じて高温漕等で１５０〜３００℃の温度で後硬化を行ってもかまわない。
【００４２】
前記金属箔を構成する金属は、例えば銅または銅系合金、アルミまたはアルミ系合金、鉄または鉄系合金が挙げられる。
【００４３】
以下、本発明を実施例および比較例により詳細に説明するが、本発明はこれに限定されるものではない。
【実施例】
実施例１
▲１▼樹脂ワニスの調製
ノボラック型シアネート樹脂（ロンザジャパン株式会社製、プリマセット ＰＴ−６０、重量平均分子量約２，６００）２０重量％（以下、％と略す）、ビフェニルジメチレン型エポキシ樹脂（日本化薬株式会社製、ＮＣ−３０００Ｐ、エポキシ当量２７５）１１％、ビフェニルジメチレン型フェノール樹脂（明和化成株式会社製、ＭＥＨ−７８５１−Ｓ、水酸基当量２０３）９％、及びエポキシシラン型カップリング剤（日本ユニカー株式会社製、Ａ−１８７）０．３重量部（以下、部と略す）をメチルエチルケトンに常温で溶解し、球状溶融シリカＳＦＰ−１０Ｘ （電気化学工業株式会社製、平均粒径０．３μｍ）１０％及び球状溶融シリカＳＯ−３２Ｒ（株式会社アドマテックス社製、平均粒径１．５μｍ）５０％を添加し、高速攪拌機を用いて１０分攪拌して樹脂ワニスを調製した。
【００４４】
▲２▼プリプレグの製造
上述の樹脂ワニスを芳香族ポリエステル不織布（厚さ４０μｍ、三菱製紙製、Ｇ７−２８０Ｔ）に含浸し、１２０℃の加熱炉で２分乾燥してワニス固形分（プリプレグ中に樹脂とシリカの占める割合）が約７０％のプリプレグを得た。
【００４５】
▲３▼プリント配線板の製造
上述のプリプレグを１２枚数重ね、両面に１８μｍの銅箔を重ねて、圧力４ＭＰａ、温度２００℃で２時間加熱加圧成形することによって０．６ｍｍの両面プリント配線板用基板を得た。他の厚みのプリント配線板用基板は、プリプレグをそれに応じた枚数積層する事によって得た。
【００４６】
（実施例２）
有機不織布として、以下のものを用いた以外は、実施例１と同様にした。芳香族ポリエステルに代えて、芳香族ポリアミド不織布（厚さ４０μｍ、王子製紙製、ＡＰＴ−２２）を用いた。
【００４７】
（実施例３）
配合量を以下の通りにした以外は、実施例１と同様にした。ノボラック型シアネート樹脂（プリマセット ＰＴ−６０）５％、ビフェニルジメチレン型エポキシ樹脂（ＮＣ−３０００Ｐ）２０％、ビフェニルジメチレン型フェノール樹脂（ＭＥＨ−７８５１−Ｓ）１５％、及びエポキシシラン型カップリング剤（Ａ−１８７）０．３部をメチルエチルケトンに常温で溶解し、球状溶融シリカ（ＳＦＰ−１０Ｘ ）１０％及び球状溶融シリカ（ＳＯ−３２Ｒ）５０％を添加した。
【００４８】
（実施例４）
配合量を以下の通りにした以外は、実施例１と同様にした。ノボラック型シアネート樹脂（プリマセット ＰＴ−３０）３０％、ノボラック型シアネート樹脂（プリマセット ＰＴ−６０）３０％、ビフェニルジメチレン型エポキシ樹脂（ＮＣ−３０００Ｐ）５％、ビフェニルジメチレン型フェノール樹脂（ＭＥＨ−７８５１−Ｓ）５％、及びエポキシシラン型カップリング剤（Ａ−１８７）０．３部をメチルエチルケトンに常温で溶解し、球状溶融シリカ（ＳＦＰ−１０Ｘ）５％及び球状溶融シリカ（ＳＯ−３２Ｒ）２５％を添加した。
【００４９】
（実施例５）
ビフェニルジメチレン型エポキシ樹脂を以下の通りにした以外は、実施例１と同様にした。ビフェニルジメチレン型エポキシ樹脂に代えて、ノボラック型エポキシ樹脂（大日本インキ化学工業株式会社製、エピクロン Ｎ−７７５、エポキシ当量１９０）を用いた。
【００５０】
（実施例６）
ビフェニルジメチレン型フェノール樹脂を以下の通りにした以外は、実施例１と同様にした。ビフェニルジメチレン型フェノール樹脂に代えて、ノボラック樹脂（住友ベークライト株式会社製、ＰＲ−５１７１４、水酸基当量１０３）を用いた。
【００５１】
（実施例７）
球状溶融シリカを以下の通りにした以外は、実施例１と同様にした。球状溶融シリカＳＦＰ−１０Ｘ及びＳＯ−３２Ｒに代えて、ＦＢ−５ＳＤＸ（電気化学工業株式会社製、平均粒径５μｍ）を用いた。
【００５２】
（実施例８）
配合量を以下の通りにした以外は、実施例１と同様にした。ノボラック型シアネート樹脂（プリマセット ＰＴ−６０）１０％、ビフェニルジメチレン型エポキシ樹脂（ＮＣ−３０００Ｐ）６％、ビフェニルジメチレン型フェノール樹脂（ＭＥＨ−７８５１−Ｓ）４％、及びエポキシシラン型カップリング剤（Ａ−１８７）０．３部をメチルエチルケトンに常温で溶解し、球状溶融シリカ（ＳＦＰ−１０Ｘ ）３０％及び球状溶融シリカ（ＳＯ−３２Ｒ）５０％を添加した。
【００５３】
（実施例９）
配合量を以下の通りにした以外は、実施例１と同様にした。ノボラック型シアネート樹脂（プリマセット ＰＴ−３０）１５％、ノボラック型シアネート樹脂（プリマセット ＰＴ−６０）２５％、ビフェニルジメチレン型エポキシ樹脂（ＮＣ−３０００Ｐ）１７％、ビフェニルジメチレン型フェノール樹脂（ＭＥＨ−７８５１−Ｓ）１３％、及びエポキシシラン型カップリング剤（Ａ−１８７）０．３部をメチルエチルケトンに常温で溶解し、球状溶融シリカ（ＳＦＰ−１０Ｘ）４％及び球状溶融シリカ（ＳＯ−３２Ｒ）２６％を添加した。
【００５４】
（実施例１０）
配合量を以下の通りにした以外は、実施例１と同様にした。ビスフェノールＡ型シアネート樹脂（旭化成エポキシ株式会社製、ＡｒｏＣｙ Ｂ−３０）１０％、ビフェニルジメチレン型エポキシ樹脂（ＮＣ−３０００Ｐ）６％、ビフェニルジメチレン型フェノール樹脂（ＭＥＨ−７８５１−Ｓ）４％、及びエポキシシラン型カップリング剤（Ａ−１８７）０．３部をメチルエチルケトンに常温で溶解し、球状溶融シリカ（ＳＦＰ−１０Ｘ ）３０％及び球状溶融シリカ（ＳＯ−３２Ｒ）５０％を添加した。
【００５５】
（比較例１）
配合量を以下の通りにした以外は、実施例１と同様にした。ビフェニルジメチレン型エポキシ樹脂（ＮＣ−３０００Ｐ）２３％、ビフェニルジメチレン型フェノール樹脂（ＭＥＨ−７８５１−Ｓ）１７％、硬化助剤２−メチルイミダゾール（四国化成工業株式会社製、２ＭＺ）０．４部、及びエポキシシラン型カップリング剤（Ａ−１８７）０．３部をメチルエチルケトンに常温で溶解し、球状溶融シリカ（ＳＦＰ−１０Ｘ ）１０％及び球状溶融シリカ（ＳＯ−３２Ｒ）５０％を添加した。
【００５６】
（比較例２）
配合量を以下の通りにした以外は、実施例１と同様にした。ノボラック型シアネート樹脂（プリマセット ＰＴ−６０）５０％、ビフェニルジメチレン型エポキシ樹脂（ＮＣ−３０００Ｐ）２８％、ビフェニルジメチレン型フェノール樹脂（ＭＥＨ−７８５１−Ｓ）２２％を添加した。
【００５７】
（比較例３）
芳香族ポリエステル不織布の代わりに、ガラス繊維（厚さ５０μｍ、日東紡株式会社製、ＷＥＡ−１０８０）を用いた以外は、実施例１と同様にした。
【００５８】
（比較例４）
芳香族ポリエステル不織布の代わりに、ガラス不織布（厚さ２２０μｍ、キュムラス株式会社製、ＥＰＭ４０２５）を用いた以外は、実施例１と同様にした。
【００５９】
実施例および比較例で得られた多層プリント配線板について、以下の評価を行った。評価項目を、評価方法と共に示す。得られた結果を表１に示す。
▲１▼ガラス転移温度
厚さ０．６ｍｍの両面多層プリント配線板を全面エッチングし、得られた積層板から１０ｍｍ×６０ｍｍのテストピースを切り出し、ＴＡインスツルメント社製動的粘弾性測定装置ＤＭＡ９８３を用いて３℃／分で昇温し、ｔａｎδのピーク位置をガラス転移温度とした。
【００６０】
▲２▼誘電率・誘電正接
厚さ１．０ｍｍの両面多層プリント配線板を全面エッチングし、得られた積層板から９７ｍｍ×２５ｍｍ、５３ｍｍ×２５ｍｍ、３７ｍｍ×２５ｍｍのテストピースを切り出し、トリプレート線路共振法により比誘電率、誘電正接を測定した。
【００６１】
▲３▼難燃性
ＵＬ−９４規格に従い、１．０ｍｍ厚のテストピースを垂直法により測定した。
【００６２】
▲４▼吸水率
厚さ０．６ｍｍの両面多層プリント配線板を全面エッチングし、得られた積層板から５０ｍｍ×５０ｍｍのテストピースを切り出し、ＪＩＳ Ｃ６４８１に従い測定した。
【００６３】
▲５▼レーザ加工性
厚さ０．０５ｍｍの両面多層プリント配線板を全面エッチングし、得られた積層板をＵＶ ＹＡＧレーザ（三菱電機製）で加工し上部及び断面を顕微鏡観察した。
【００６４】
▲６▼吸湿半田耐熱性
厚さ０．６ｍｍの両面銅張積層板から５０ｍｍ×５０ｍｍに切り出し、ＪＩＳ６４８１に従い半面エッチングを行ってテストピースを作成した。１２５℃のプレッシャークッカーで処理した後、２６０℃のはんだ槽に銅箔面を下にして浮かべ、１８０秒後に膨れが発生する処理時間を計測した。
【００６５】
▲７▼熱膨張係数
厚さ０．１ｍｍの両面銅張積層板を全面エッチングし、得られた積層板から縦・横方向それぞれ４ｍｍ×２０ｍｍのテストピースを切り出し、ＴＭＡを用いて縦・横方向の線膨張係数を５℃／分で測定した。
【００６６】
▲８▼接続信頼性
厚さ０．４ｍｍの４層板（デージーチェーン）を作製し、２６０℃／６０秒、常温／６０秒のホットオイル試験を行った。１００穴あたりの導通抵抗が初期値の１２０％に変化するまでのサイクル数を測定した。
【００６７】
【表１】

【００６８】
表から明らかなように実施例１〜１０は、誘電率が低く、レーザ加工性、難燃性に優れていた。
また、実施例１、２、５〜８および１０は、特に面方向（縦および横方向）の膨張率が低くなっていた。
また、実施例１〜３は、特に吸湿半田耐熱性にも優れていた。
【００６９】
【発明の効果】
本発明によれば、誘電特性、レーザ加工性および難燃性に優れたプリプレグおよびプリント配線板を得ることができる。
また、特定のエポキシ樹脂を用いる場合、特に吸湿半田耐熱性に優れたプリプレグおよびプリント配線板を得ることができる。
また、特定の無機充填材を用いる場合、特に熱膨張係数の低いプリプレグおよびプリント配線板を得ることができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a prepreg and a printed wiring board using the same.
[0002]
[Prior art]
In the field of semiconductors, with the progress of high-density mounting technology, there is a trend to shift semiconductor elements from conventional surface mounting to area mounting. New packages such as a ball grid array (BGA) and a chip scale package (CSP) have appeared and are increasing in response to such high-density mounting technology. Therefore, more attention has been paid to rigid substrates for interposers than before, and demands for substrates having high heat resistance and low thermal expansion have been increasing.
[0003]
Further, in recent years, with the demand for higher functionality of electronic devices, high-density integration, high-density mounting, and the like of electronic components have been advanced. For this reason, printed wiring boards and the like that are compatible with high-density mounting and are used in these devices are becoming smaller and more dense than ever before. In order to cope with such high density of printed wiring boards and the like, build-up multilayer wiring boards are often used.
[0004]
In order to reduce the size and increase the density of the build-up multilayer wiring board, it is necessary to connect the layers with fine vias. Therefore, the via of the build-up multilayer wiring board is formed by laser processing. However, in a prepreg using a glass cloth as a base material, uniform and fine vias could not be formed because laser processing was difficult. Therefore, a prepreg using an aramid fiber base material is disclosed (for example, see Patent Document 1).
At the same time, the speed of information processing equipment is required to be higher, and the clock frequency of the CPU is increasing. Therefore, it is required to increase the signal propagation speed, and a printed wiring board having a low dielectric constant and a low dielectric loss tangent is required to realize this.
[0005]
In addition, resin members used for semiconductors are often required to have flame retardancy. Conventionally, in order to impart flame retardancy, it is common to use a halogen-based flame retardant such as brominated epoxy in the case of an epoxy resin. However, use of halogen-containing compounds has been avoided due to problems such as dioxin generation. Therefore, a halogen-free flame retardant system has been demanded, and phosphorus-based flame retardants such as phosphate esters and red phosphorus have been studied. However, these phosphorus-based flame retardants are liable to be hydrolyzed and have poor reactivity with a resin, so that there are problems such as a decrease in solder heat resistance.
[0006]
[Patent Document 1]
JP-A-62-261190
[Problems to be solved by the invention]
An object of the present invention is to provide a prepreg and a printed wiring board having excellent dielectric properties, laser workability, and flame retardancy.
[0008]
[Means for Solving the Problems]
Such an object is achieved by the present invention described in the following (1) to (12).
(1) A prepreg obtained by impregnating a nonwoven fabric composed of organic fibers with a resin composition containing a cyanate resin and / or a prepolymer thereof and an inorganic filler, and cured by curing the prepreg. A prepreg characterized in that the thermal expansion coefficient in the plane direction at a temperature lower than the glass transition point of the product is 50 ppm / ° C or lower.
(2) The prepreg according to (1), wherein the resin composition further contains an epoxy resin.
(3) The prepreg according to (1) or (2), wherein the resin composition further contains a phenol resin.
(4) The prepreg according to any one of (1) to (3), wherein the resin constituting the organic fiber has a glass transition point of 200 ° C. or higher.
(5) The prepreg according to any one of (1) to (4), wherein the resin constituting the organic fiber has a wholly aromatic polyamide resin as a main component.
(6) The prepreg according to any one of (1) to (4), wherein the resin constituting the organic fiber has a wholly aromatic polyester resin as a main component.
(7) The prepreg according to any one of (1) to (6), wherein the cyanate resin and / or a prepolymer thereof is a novolak-type cyanate resin and / or a prepolymer thereof.
(8) The prepreg according to any one of (1) to (7), wherein the content of the cyanate resin and / or the prepolymer thereof is 5 to 60% by weight of the whole resin composition.
(9) The prepreg according to any one of (1) to (8), wherein the epoxy resin is an arylalkylene type epoxy resin.
(10) The prepreg according to any of (1) to (9), wherein the phenol resin is an arylalkylene type phenol resin.
(11) The prepreg according to any one of (1) to (10), wherein the content of the inorganic filler is 30 to 80% by weight of the entire resin composition.
(12) A printed wiring board formed by laminating a metal foil on the prepreg according to any one of (1) to (11) and subjecting the prepreg to heat and pressure molding.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the prepreg of the present invention and a printed wiring board using the same will be described in detail.
The prepreg of the present invention is a prepreg obtained by impregnating a nonwoven fabric composed of organic fibers with a resin composition containing a cyanate resin and / or a prepolymer thereof, and an inorganic filler, and curing the prepreg. The cured product obtained is characterized in that the thermal expansion coefficient in the plane direction at a glass transition point or lower is 50 ppm / ° C. or lower.
In addition, the printed wiring board of the present invention is obtained by laminating a metal foil on the prepreg and molding by heating and pressing.
[0010]
Hereinafter, the prepreg will be described.
In the prepreg of the present invention, a cyanate resin and / or a prepolymer thereof is used. Thereby, when the prepreg of the present invention is formed into a printed wiring board, high heat resistance and low thermal expansion can be achieved.
The cyanate resin and / or a prepolymer thereof can be obtained, for example, by reacting a cyanogen halide compound with a phenol and, if necessary, prepolymerizing by a method such as heating. Specific examples include bisphenol-type cyanate resins such as a novolak-type cyanate resin, a bisphenol-A-type cyanate resin, a bisphenol-E-type cyanate resin, and a tetramethylbisphenol-F-type cyanate resin. Among these, a novolak type cyanate resin is preferred. Thereby, the heat resistance can be improved by increasing the crosslink density, and the flame retardancy of the resin composition and the like can be improved. It is considered that the novolak type cyanate resin has a high ratio of benzene rings due to its structure and is easily carbonized.
[0011]
As the novolak type cyanate resin, for example, a resin represented by the formula (I) can be used.
Embedded image

The n of the novolak type cyanate resin represented by the formula (I) is not particularly limited, but is preferably 1 to 10, and particularly preferably 1 to 7. If the amount is less than this, the novolak type cyanate resin tends to crystallize, and the solubility in a general-purpose solvent is relatively reduced, so that handling may be difficult. On the other hand, if it is more than this, the crosslink density becomes too high, and phenomena such as a decrease in water resistance and a brittle cured product may occur.
[0012]
The weight average molecular weight of the cyanate resin and / or its prepolymer is not particularly limited, but is preferably 500 to 4,500, and more preferably 600 to 3,000. When the weight-average molecular weight is less than the lower limit, tackiness occurs when the prepreg is produced, and when the prepregs come into contact with each other, they may adhere to each other or transfer of the resin may occur. On the other hand, when the value exceeds the above current value, the reaction becomes too fast, and when a printed wiring board is formed, molding failure may occur or interlayer peel strength may decrease.
[0013]
The content of the cyanate resin is not particularly limited, but is preferably 5 to 60% by weight, more preferably 10 to 50% by weight of the whole resin composition. If the content is less than the lower limit, the heat resistance and the effect of lowering the thermal expansion may decrease. If the content exceeds the upper limit, the crosslinking density increases and the free volume increases, so that the moisture resistance may decrease.
[0014]
The prepreg of the present invention is not particularly limited, but preferably uses an epoxy resin. Examples of the epoxy resin include a phenol novolak type epoxy resin, a bisphenol type epoxy resin, a naphthalene type epoxy resin, and an arylalkylene type epoxy resin. Among them, arylalkylene type epoxy resins are preferred. Thereby, the moisture absorption solder heat resistance can be improved.
[0015]
The arylalkylene type epoxy resin refers to an epoxy resin having one or more arylalkylene groups in a repeating unit. For example, xylylene type epoxy resin, biphenyl dimethylene type epoxy resin and the like can be mentioned. Among these, a biphenyl dimethylene type epoxy resin is preferable. The biphenyl dimethylene type epoxy resin can be represented by, for example, the formula (II).
Embedded image

Although n of the biphenyl dimethylene type epoxy resin represented by the formula (II) is not particularly limited, it is preferably 1 to 10, and particularly preferably 2 to 5. If the amount is less than this, the biphenyl dimethylene type epoxy resin tends to crystallize, and the solubility in a general-purpose solvent is relatively reduced, so that handling may be difficult. On the other hand, if the amount is more than this, the fluidity of the resin is reduced, which may cause molding failure.
[0016]
Further, when a printed wiring board is produced using a combination of the above-described cyanate resin and / or a prepolymer thereof (particularly novolak type cyanate resin), a phenol resin and an arylalkylene type epoxy resin (particularly biphenyl dimethylene type epoxy resin). In particular, excellent dimensional stability can be obtained.
[0017]
The content of the epoxy resin is not particularly limited, but is preferably 1 to 55% by weight, and particularly preferably 2 to 40% by weight of the whole resin composition. If the content is less than the lower limit, the reactivity of the cyanate resin may decrease, or the moisture resistance of the resulting product may decrease. If the content exceeds the upper limit, the heat resistance may decrease.
[0018]
The weight average molecular weight of the epoxy resin is not particularly limited, but is preferably from 500 to 20,000, more preferably from 800 to 15,000. When the weight average molecular weight is less than the lower limit, tackiness may occur in the prepreg, and when the prepreg is more than the upper limit, impregnation into the base material is reduced, and a uniform product may not be obtained. is there.
[0019]
The prepreg of the present invention is not particularly limited, but preferably uses a phenol resin. Examples of the phenol resin include a novolak phenol resin, a resol phenol resin, and an arylalkylene phenol resin. Among them, arylalkylene type phenol resins are preferred. As a result, the heat resistance of the moisture-absorbing solder can be further improved.
[0020]
Examples of the arylalkylene type phenol resin include a xylylene type phenol resin and a biphenyl dimethylene type phenol resin. The biphenyl dimethylene type phenol resin can be represented, for example, by the formula (III).
Embedded image

Although n of the biphenyl dimethylene type phenol resin represented by the formula (III) is not particularly limited, 1 to 12 is preferable, and 2 to 8 is particularly preferable. If it is less than this, the heat resistance may decrease. On the other hand, if it is more than this, the compatibility with other resins is lowered and the workability may be deteriorated, which is not preferable.
[0021]
The combination of the above-described cyanate resin and / or a prepolymer thereof (particularly, a novolak-type cyanate resin) and an arylalkylene-type phenol resin can control the crosslinking density and improve the adhesion between the metal and the resin.
[0022]
The content of the phenol resin is not particularly limited, but is preferably 1 to 55% by weight, and particularly preferably 5 to 40% by weight of the whole resin composition. If the content is less than the lower limit, the heat resistance may decrease, and if it exceeds the upper limit, the characteristics of low thermal expansion may be impaired.
[0023]
The weight average molecular weight of the phenol resin is not particularly limited, but is preferably 400 to 18,000, particularly preferably 500 to 15,000. When the weight average molecular weight is less than the lower limit, tackiness may occur in the prepreg, and when the prepreg is more than the upper limit, impregnation into the base material is reduced, and a uniform product may not be obtained. is there.
[0024]
In the prepreg of the present invention, an inorganic filler is used. Thereby, low thermal expansion and improvement of flame retardancy can be achieved.
In addition, the combination of the above-described cyanate resin and / or a prepolymer thereof (particularly, a novolak-type cyanate resin) and an inorganic filler can improve the elastic modulus of a printed wiring board in particular.
Examples of the inorganic filler include talc, alumina, glass, silica, and mica. Among these, silica is preferred, and fused silica (particularly, spherical fused silica) is preferred in that it has excellent low thermal expansion properties. Its shape is crushed, spherical, but the method of use according to the purpose is adopted, such as using spherical silica to reduce the melt viscosity of the resin composition to ensure impregnation into the glass substrate .
[0025]
The average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 to 5.0 μm, and particularly preferably 0.2 to 2.0 μm. If the particle size of the inorganic filler is less than the above lower limit, the viscosity of the varnish increases, which may affect the workability during prepreg production. If the upper limit is exceeded, phenomena such as sedimentation of the inorganic filler in the varnish may occur.
[0026]
Further, spherical silica having an average particle size of 5.0 μm or less (particularly, spherical fused silica) is preferred, and spherical fused silica having an average particle size of 0.01 to 2.0 μm is particularly preferred. Thereby, the filling property of the inorganic filler can be improved.
[0027]
The content of the inorganic filler is not particularly limited, but is preferably from 30 to 80% by weight, and particularly preferably from 40 to 70% by weight of the entire resin composition. When the content is within the above range, low thermal expansion and low water absorption can be obtained.
[0028]
In the prepreg of the present invention, the cyanate resin and / or a prepolymer thereof, a part of an epoxy resin and a phenol resin, a vinyl ester resin, another thermosetting resin such as a melamine resin, a phenoxy resin, a polyimide resin, a polyamide imide resin, You may use together with thermoplastic resins, such as polyphenylene oxide resin and polyether sulfone resin.
[0029]
In the prepreg of the present invention, although not particularly limited, it is preferable to use a coupling agent. The coupling agent improves the wettability of the interface between the resin and the inorganic filler, so that the resin and the filler can be uniformly fixed to the base material and improves the heat resistance, especially the solder heat resistance after moisture absorption. Mix. As the coupling agent, any one can be used as long as it is generally used. Among them, one or more kinds selected from epoxysilane coupling agent, titanate coupling agent, aminosilane coupling agent and silicone oil type coupling agent can be used. The use of a coupling agent is preferable in terms of high wettability with the inorganic filler interface and improvement in heat resistance.
[0030]
In the present invention, the content of the coupling agent is not particularly limited, but is preferably 0.05 to 3 parts by weight based on the whole inorganic filler. If the content is less than the lower limit, the filler cannot be sufficiently coated and sufficient heat resistance may not be obtained.If the content exceeds the upper limit, the reaction may be affected, and the flexural strength or the like may be reduced. is there.
[0031]
In the prepreg of the present invention, a curing accelerator may be used as necessary. Known substances can be used as the curing accelerator. For example, organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonatocobalt (II), and trisacetylacetonatocobalt (III), triethylamine, tributylamine, diazabicyclo [2, Tertiary amines such as 2,2] octane, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxy Imidazoles such as imidazole and 2-phenyl-4,5-dihydroxyimidazole; phenol compounds such as phenol, bisphenol A and nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid, and paratoluenesulfonic acid; and mixtures thereof. Can be
[0032]
In the prepreg of the present invention, additives other than the above components can be added as necessary. The resin composition composed of each of these resins and each additive is impregnated into a nonwoven fabric composed of organic fibers described later.
[0033]
In the prepreg of the present invention, the above-mentioned resin composition is impregnated into a nonwoven fabric composed of organic fibers.
Examples of the resin constituting the organic fiber include an aromatic polyamide resin, a polyamide resin, an aromatic polyester resin, a polyester resin, a polyimide resin, and a fluororesin. Among these, it is preferable that one or more resins selected from aromatic polyester resins (particularly wholly aromatic polyester resins) and aromatic polyamide resins (particularly wholly aromatic polyamide resins) are used as main components. Thereby, when the prepreg is used as a printed wiring board, laser workability can be improved. Particularly, an aromatic polyester resin (a wholly aromatic polyester resin) is preferable. Thereby, the electrical characteristics (dielectric characteristics) of the prepreg can be further improved.
[0034]
The glass transition point of the resin constituting the organic fiber is not particularly limited, but is preferably 200 ° C. or higher, and particularly preferably 250 to 400 ° C. If the glass transition point is less than the lower limit, flip-chip mounting may be reduced.
[0035]
Examples of the method of impregnating the base material with the resin composition include a method of immersing the base material in a resin varnish, a method of applying with a variety of coaters, and a method of spraying with a spray. Among these, the method of immersing the base material in the resin varnish is preferable. Thereby, the impregnation property of the resin composition to the base material can be improved. When the substrate is immersed in the resin varnish, ordinary impregnation coating equipment can be used.
[0036]
The solvent used for the resin varnish desirably exhibits good solubility in the resin composition, but a poor solvent may be used as long as it does not adversely affect the solvent. Examples of the solvent exhibiting good solubility include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like.
[0037]
The solid content of the resin varnish is not particularly limited, but the solid content of the resin composition is preferably 30 to 80% by weight, and particularly preferably 40 to 70% by weight. Thereby, the impregnation property of the resin varnish into the substrate can be improved.
A prepreg can be obtained by impregnating the base material with the resin composition and drying at a predetermined temperature, for example, 90 to 180 ° C.
[0038]
In the prepreg of the present invention, the cured product obtained by curing the above prepreg has a thermal expansion coefficient (α ₁ ) in the plane direction at a glass transition point or lower of 50 ppm / ° C. or lower. That is, by xy direction expansion of the cured product at a temperature below the glass transition region (alpha ₁ region) a (alpha ₁₎ and less than the lower limit, it is possible to improve the connection reliability between the semiconductor chip.
For example, since the coefficient of expansion of copper is 17 ppm / ° C., if the coefficient of linear expansion in the plane direction of the substrate is around 17 ppm / ° C., the difference in the amount of thermal expansion between copper and the substrate is reduced, and the stress is reduced. I do. Therefore, it is considered that connection reliability between the semiconductor chip and the substrate due to thermal shock can be improved.
[0039]
Further, the thermal expansion tension coefficient (α ₁ ) of the cured product in the surface direction is preferably from 10 to 30 ppm / ° C., particularly preferably from 15 to 20 ppm / ° C. When the coefficient of thermal expansion is within the above range, the connection reliability of the substrate can be particularly excellent.
The coefficient of thermal expansion in the plane direction can be measured by a method described in JIS K-7197 using a thermomechanical analyzer (TMA). The measurement principle is to set the measurement sample on the stage, apply a constant load, raise the temperature at a constant speed, detect the amount of expansion that occurs as an electrical output with a differential transformer, and examine the relationship with temperature. is there.
Here, the plane direction means a longitudinal direction indicating the flow direction of the prepreg (mechanical direction of the prepreg) and a lateral direction indicating the width direction of the prepreg (anti-machine direction of the prepreg).
[0040]
Next, the printed wiring board will be described.
The printed wiring board of the present invention is obtained by laminating a metal foil on the above-mentioned prepreg and subjecting it to heat and pressure molding. Thereby, a printed wiring board excellent in heat resistance, low expansion property and flame retardancy can be obtained.
In the case of one prepreg, the metal foil is laminated on both upper and lower surfaces or one surface. Also, two or more prepregs can be laminated. When laminating two or more prepregs, a metal foil or a film is laminated on the outermost upper and lower surfaces or one surface of the laminated prepreg.
[0041]
Next, a printed wiring board can be obtained by subjecting a prepreg and a metal foil to each other to heat and pressure molding. The heating temperature is not particularly limited, but is preferably from 120 to 220 ° C, particularly preferably from 150 to 200 ° C. The pressure to be applied is not particularly limited, but is preferably 1.5 to 5 MPa, and particularly preferably 2 to 4 MPa. If necessary, post-curing may be performed at a temperature of 150 to 300 ° C. in a high-temperature bath or the like.
[0042]
Examples of the metal constituting the metal foil include copper or a copper-based alloy, aluminum or an aluminum-based alloy, iron or an iron-based alloy.
[0043]
Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
【Example】
Example 1
{Circle around (1)} Preparation of resin varnish Novolak type cyanate resin (manufactured by Lonza Japan Co., Ltd., Primaset PT-60, weight average molecular weight about 2,600) 20% by weight (hereinafter abbreviated as%), biphenyl dimethylene type epoxy resin ( Nippon Kayaku Co., Ltd., NC-3000P, epoxy equivalent 275) 11%, biphenyl dimethylene type phenol resin (Meiwa Kasei Co., Ltd., MEH-7851-S, hydroxyl equivalent 203) 9%, and epoxy silane type coupling 0.3 parts by weight (hereinafter abbreviated as "parts") of an agent (manufactured by Nippon Unicar Co., Ltd., A-187) is dissolved in methyl ethyl ketone at room temperature, and spherical fused silica SFP-10X (manufactured by Denki Kagaku Kogyo Co., Ltd .; 0.3 μm) 10% and spherical fused silica SO-32R (manufactured by Admatechs Co., Ltd., average particle size 1.5 μm) 50 It was added, a resin varnish was prepared by stirring 10 minutes using a high speed stirrer.
[0044]
{Circle around (2)} Production of prepreg The above resin varnish is impregnated into an aromatic polyester nonwoven fabric (40 μm thick, manufactured by Mitsubishi Paper Mills, G7-280T), dried in a heating furnace at 120 ° C. for 2 minutes, and solidified in varnish. A prepreg having a ratio of about 70% (resin and silica) was obtained.
[0045]
{Circle around (3)} Production of Printed Wiring Board A double-sided printed wiring board having a thickness of 0.6 mm is formed by laminating 12 prepregs as described above, laminating 18 μm copper foil on both sides, and applying heat and pressure at a pressure of 4 MPa and a temperature of 200 ° C. for 2 hours. A substrate was obtained. Printed wiring board substrates having other thicknesses were obtained by laminating a corresponding number of prepregs.
[0046]
(Example 2)
The same procedure as in Example 1 was performed except that the following was used as the organic nonwoven fabric. Instead of the aromatic polyester, an aromatic polyamide nonwoven fabric (40 μm thick, manufactured by Oji Paper, APT-22) was used.
[0047]
(Example 3)
The procedure was the same as in Example 1, except that the amounts were as follows. Novolak type cyanate resin (Primaset PT-60) 5%, biphenyl dimethylene type epoxy resin (NC-3000P) 20%, biphenyl dimethylene type phenol resin (MEH-7851-S) 15%, and epoxy silane type coupling 0.3 part of Agent (A-187) was dissolved in methyl ethyl ketone at room temperature, and 10% of spherical fused silica (SFP-10X) and 50% of spherical fused silica (SO-32R) were added.
[0048]
(Example 4)
The procedure was the same as in Example 1, except that the amounts were as follows. Novolak type cyanate resin (Primaset PT-30) 30%, Novolak type cyanate resin (Primaset PT-60) 30%, Biphenyl dimethylene type epoxy resin (NC-3000P) 5%, Biphenyl dimethylene type phenol resin (MEH) -7851-S) and 0.3 parts of an epoxysilane type coupling agent (A-187) were dissolved in methyl ethyl ketone at room temperature, and spherical fused silica (SFP-10X) 5% and spherical fused silica (SO-32R) were dissolved. ) 25% was added.
[0049]
(Example 5)
Example 1 was repeated except that the biphenyl dimethylene type epoxy resin was changed as follows. In place of the biphenyl dimethylene type epoxy resin, a novolak type epoxy resin (Epiclon N-775, epoxy equivalent 190, manufactured by Dainippon Ink and Chemicals, Inc.) was used.
[0050]
(Example 6)
Example 1 was repeated except that the biphenyl dimethylene type phenol resin was changed as follows. A novolak resin (PR-51714, hydroxyl equivalent 103, manufactured by Sumitomo Bakelite Co., Ltd.) was used in place of the biphenyl dimethylene type phenol resin.
[0051]
(Example 7)
Example 1 was repeated except that the spherical fused silica was changed as follows. In place of spherical fused silica SFP-10X and SO-32R, FB-5SDX (manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 5 μm) was used.
[0052]
(Example 8)
The procedure was the same as in Example 1, except that the amounts were as follows. Novolak type cyanate resin (Primaset PT-60) 10%, biphenyl dimethylene type epoxy resin (NC-3000P) 6%, biphenyl dimethylene type phenol resin (MEH-7851-S) 4%, and epoxy silane type coupling 0.3 part of Agent (A-187) was dissolved in methyl ethyl ketone at room temperature, and 30% of spherical fused silica (SFP-10X) and 50% of spherical fused silica (SO-32R) were added.
[0053]
(Example 9)
The procedure was the same as in Example 1, except that the amounts were as follows. Novolak-type cyanate resin (Primaset PT-30) 15%, novolak-type cyanate resin (Primaset PT-60) 25%, biphenyldimethylene-type epoxy resin (NC-3000P) 17%, biphenyldimethylene-type phenol resin (MEH) -7851-S) 13% and epoxysilane-type coupling agent (A-187) 0.3 part were dissolved in methyl ethyl ketone at room temperature, and spherical fused silica (SFP-10X) 4% and spherical fused silica (SO-32R) were dissolved. ) 26% was added.
[0054]
(Example 10)
The procedure was the same as in Example 1, except that the amounts were as follows. Bisphenol A type cyanate resin (AroCy B-30, manufactured by Asahi Kasei Epoxy Co., Ltd.) 10%, biphenyl dimethylene type epoxy resin (NC-3000P) 6%, biphenyl dimethylene type phenol resin (MEH-7851-S) 4%, And 0.3 part of epoxysilane type coupling agent (A-187) was dissolved in methyl ethyl ketone at room temperature, and 30% of spherical fused silica (SFP-10X) and 50% of spherical fused silica (SO-32R) were added.
[0055]
(Comparative Example 1)
The procedure was the same as in Example 1, except that the amounts were as follows. Biphenyl dimethylene type epoxy resin (NC-3000P) 23%, biphenyl dimethylene type phenol resin (MEH-7851-S) 17%, curing aid 2-methylimidazole (Shikoku Chemical Industry Co., Ltd., 2MZ) 0.4 And 0.3 parts of an epoxysilane-type coupling agent (A-187) were dissolved in methyl ethyl ketone at room temperature, and 10% of spherical fused silica (SFP-10X) and 50% of spherical fused silica (SO-32R) were added. .
[0056]
(Comparative Example 2)
The procedure was the same as in Example 1, except that the amounts were as follows. 50% of novolak type cyanate resin (Primaset PT-60), 28% of biphenyl dimethylene type epoxy resin (NC-3000P), and 22% of biphenyl dimethylene type phenol resin (MEH-7851-S) were added.
[0057]
(Comparative Example 3)
Example 1 was repeated except that a glass fiber (thickness: 50 μm, manufactured by Nittobo Co., Ltd., WEA-1080) was used instead of the aromatic polyester nonwoven fabric.
[0058]
(Comparative Example 4)
Example 1 was repeated except that a glass nonwoven fabric (thickness: 220 μm, manufactured by Cumulus, EPM4025) was used instead of the aromatic polyester nonwoven fabric.
[0059]
The following evaluations were performed on the multilayer printed wiring boards obtained in Examples and Comparative Examples. The evaluation items are shown together with the evaluation method. Table 1 shows the obtained results.
{Circle around (1)} A double-sided multilayer printed wiring board having a glass transition temperature thickness of 0.6 mm is entirely etched, and a test piece of 10 mm × 60 mm is cut out from the obtained laminate, and a dynamic viscoelasticity measuring device DMA983 manufactured by TA Instruments Co., Ltd. And the temperature was raised at 3 ° C./min, and the peak position of tan δ was taken as the glass transition temperature.
[0060]
{Circle around (2)} Double-sided multilayer printed wiring board having a dielectric constant and a dielectric loss tangent of 1.0 mm is entirely etched, and test pieces of 97 mm × 25 mm, 53 mm × 25 mm, and 37 mm × 25 mm are cut out from the obtained laminate, and a triplate line is obtained. The relative permittivity and the dielectric loss tangent were measured by the resonance method.
[0061]
{Circle around (3)} Flame retardancy According to the UL-94 standard, a test piece having a thickness of 1.0 mm was measured by a vertical method.
[0062]
{Circle around (4)} Water absorption coefficient A double-sided multilayer printed wiring board having a thickness of 0.6 mm was entirely etched, and a test piece of 50 mm × 50 mm was cut out from the obtained laminated board and measured according to JIS C6481.
[0063]
{Circle around (5)} Laser workability The double-sided multilayer printed wiring board having a thickness of 0.05 mm was entirely etched, and the obtained laminate was processed with a UV YAG laser (manufactured by Mitsubishi Electric Corporation), and the upper part and the cross section were observed with a microscope.
[0064]
{Circle around (6)} Moisture-absorbing solder heat resistance A test piece was cut out from a double-sided copper-clad laminate having a thickness of 0.6 mm into 50 mm × 50 mm and subjected to half-side etching in accordance with JIS6481. After the treatment with a pressure cooker at 125 ° C., the copper foil surface was floated down on a solder bath at 260 ° C., and the treatment time at which swelling occurred after 180 seconds was measured.
[0065]
(7) Thermal expansion coefficient The whole surface of the double-sided copper-clad laminate with a thickness of 0.1 mm is etched, and a test piece of 4 mm × 20 mm in each of the vertical and horizontal directions is cut out from the obtained laminate, and the vertical and horizontal directions are measured using TMA. Was measured at 5 ° C./min.
[0066]
{Circle around (8)} Connection reliability A four-layer plate (daisy chain) having a thickness of 0.4 mm was prepared and subjected to a hot oil test at 260 ° C./60 seconds and normal temperature / 60 seconds. The number of cycles until the conduction resistance per 100 holes changed to 120% of the initial value was measured.
[0067]
[Table 1]

[0068]
As is clear from the table, Examples 1 to 10 had a low dielectric constant and were excellent in laser workability and flame retardancy.
Further, in Examples 1, 2, 5 to 8 and 10, particularly the expansion rates in the plane direction (vertical and horizontal directions) were low.
Further, Examples 1 to 3 were particularly excellent in heat resistance to moisture absorption solder.
[0069]
【The invention's effect】
According to the present invention, it is possible to obtain a prepreg and a printed wiring board having excellent dielectric properties, laser workability and flame retardancy.
In addition, when a specific epoxy resin is used, a prepreg and a printed wiring board having particularly excellent moisture absorption solder heat resistance can be obtained.
When a specific inorganic filler is used, a prepreg and a printed wiring board having particularly low thermal expansion coefficients can be obtained.

Claims (12)

A prepreg obtained by impregnating a nonwoven fabric composed of organic fibers with a resin composition containing a cyanate resin and / or a prepolymer thereof and an inorganic filler,
A prepreg, wherein a cured product obtained by curing the prepreg has a thermal expansion coefficient in a plane direction at a glass transition point or lower of 50 ppm / ° C. or lower. The prepreg according to claim 1, wherein the resin composition further contains an epoxy resin. The prepreg according to claim 1, wherein the resin composition further contains a phenol resin. The prepreg according to any one of claims 1 to 3, wherein the resin constituting the organic fibers has a glass transition point of 200 ° C or higher. The prepreg according to any one of claims 1 to 4, wherein the resin constituting the organic fiber has a wholly aromatic polyamide resin as a main component. The prepreg according to any one of claims 1 to 4, wherein the resin constituting the organic fiber has a wholly aromatic polyester resin as a main component. The prepreg according to any one of claims 1 to 6, wherein the cyanate resin and / or a prepolymer thereof is a novolak-type cyanate resin and / or a prepolymer thereof. The prepreg according to any one of claims 1 to 7, wherein the content of the cyanate resin and / or a prepolymer thereof is 5 to 60% by weight of the entire resin composition. The prepreg according to any one of claims 1 to 8, wherein the epoxy resin is an arylalkylene type epoxy resin. The prepreg according to any one of claims 1 to 9, wherein the phenol resin is an arylalkylene type phenol resin. The prepreg according to any one of claims 1 to 10, wherein the content of the inorganic filler is 30 to 80% by weight of the entire resin composition. A printed wiring board obtained by laminating a metal foil on the prepreg according to any one of claims 1 to 11 and molding by heating and pressing.