JP3871032B2 - Liquid epoxy resin composition and flip chip type semiconductor device - Google Patents

Description

で表されるアビエチン酸
を必須成分とし、上記（ｄ）成分を（ａ），（ｂ）成分の合計１００重量部に対して０．５〜５重量部含有することを特徴とする液状エポキシ樹脂組成物を提供する。
【００１０】
以下、本発明につき更に詳しく説明する。
本発明の半導体封止材（液状エポキシ樹脂組成物）において、（ａ）液状エポキシ樹脂としては、１分子中に２個以上のエポキシ基があればいかなるものでも使用可能であるが、特に、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂等のビスフェノール型エポキシ樹脂、フェノールノボラック型エポキシ樹脂、クレゾールノボラック型エポキシ樹脂等のノボラック型エポキシ樹脂、ナフタレン型エポキシ樹脂、ビフェニル型エポキシ樹脂、シクロペンタジエン型エポキシ樹脂などが例示される。これらの中でも室温で液状のエポキシ樹脂が望ましい。これらのエポキシ樹脂には、下記構造で示されるエポキシ樹脂を浸入性に影響を及ぼさない範囲で添加しても何ら問題はない。
【００１１】
【化２】

【００１２】
上記液状エポキシ樹脂中の全塩素含有量は、１５００ｐｐｍ以下、望ましくは１０００ｐｐｍ以下であることが好ましい。また、１００℃で５０％エポキシ樹脂濃度における２０時間での抽出水塩素が１０ｐｐｍ以下であることが好ましい。全塩素含有量が１５００ｐｐｍを超え、又は抽出水塩素が１０ｐｐｍを超えると半導体素子の信頼性、特に耐湿性に悪影響を与えるおそれがある。
【００１３】
本発明に使用する（ｂ）硬化剤は、特に限定されるものではないが、酸無水物硬化剤が信頼性を向上させるために有効である。酸無水物硬化剤としては、例えば、メチルテトラヒドロ無水フタル酸、メチルヘキサヒドロ無水フタル酸、ヘキサヒドロ無水フタル酸、無水メチルハイミック酸、ピロメリット酸二無水物、マレイン化アロオシメン、ベンゾフェノンテトラカルボン酸二無水物、３，３’，４，４’−ビフェニルテトラビスベンゾフェノンテトラカルボン酸二無水物、（３，４−ジカルボキシフェニル）エーテル二無水物、ビス（３，４−ジカルボキシフェニル）メタン二無水物、２，２−ビス（３，４−ジカルボキシフェニル）プロパン二無水物、３，４−ジメチル−６−（２−メチル−１−プロぺニル）−１，２，３，６−テトラハイドロフタル酸及び１−イソプロピル−４−メチル−バイサクロ［２．２．２］オクト−５−エン−２，３−ジカルボン酸の混合物などが挙げられる。
【００１４】
本発明においては、特に、３，４−ジメチル−６−（２−メチル−１−プロぺニル）−１，２，３，６−テトラハイドロフタル酸及び１−イソプロピル−４−メチル−バイサクロ［２．２．２］オクト−５−エン−２，３−ジカルボン酸の混合物を使用することが好ましい。なお、３，４−ジメチル−６−（２−メチル−１−プロぺニル）−１，２，３，６−テトラハイドロフタル酸と、１−イソプロピル−４−メチル−バイサクロ［２．２．２］オクト−５−エン−２，３−ジカルボン酸の混合比としては、前者が２０〜６０重量％、後者が８０〜４０重量％（合計で１００重量％）であることが望ましい。
このような硬化剤としては、例えば、油化シェルエポキシ社製のＹＨ３０６、ＹＨ３０７等が挙げられる。
【００１５】
上記混合物の硬化剤中の配合割合としては、硬化剤全体の５〜７５重量％、特に１５〜６５重量％とすることが望ましい。５重量％未満では密着性が低下し、ＰＣＴなどの高温多湿下において劣化する場合がある。７５重量％を超える量では密着性は向上するが、熱衝撃試験などの試験においてクラックが発生する場合がある。
【００１６】
本発明において、上記以外の硬化剤としては、特に制限されず、硬化性エポキシ樹脂組成物に用いられる硬化剤全般を使用することができる。この硬化剤として具体的には、上述した酸無水物全般、ジシアンジアミド、アジピン酸ヒドラジド、イソフタル酸ヒドラジドなどのカルボン酸ヒドラジドなどが挙げられる。これらの中では、特にメチルテトラヒドロ無水フタル酸、メチルヘキサヒドロ無水フタル酸、ヘキサヒドロ無水フタル酸が好ましく、従って、上記３，４−ジメチル−６−（２−メチル−１−プロぺニル）−１，２，３，６−テトラハイドロフタル酸及び１−イソプロピル−４−メチル−バイサクロ［２．２．２］オクト−５−エン−２，３−ジカルボン酸の混合物は、メチルテトラヒドロ無水フタル酸、メチルヘキサヒドロ無水フタル酸又はヘキサヒドロ無水フタル酸と併用することが好ましい。
【００１７】
なお、本発明に用いられる硬化剤の総配合量は、エポキシ樹脂を硬化させる有効量であり、その種類によって相違するが、上述した酸無水物を用いる場合は、エポキシ樹脂中のエポキシ基に対して硬化剤中の酸無水物基（−ＣＯ−Ｏ−ＣＯ−）から誘導されるカルボン酸基のモル比を０．５〜１．５の範囲にすることが好適である。０．５未満では硬化性が不十分であり、１．５を超えると未反応の酸無水物が残存し、ガラス転移温度の低下となるおそれがある。より好ましくは０．８〜１．２の範囲にすることが好適である。あるいは、上記と同様の理由により、エポキシ樹脂中のエポキシ基に対して酸無水物中の酸無水物基のモル比が好ましくは０．３〜０．７、より好ましくは０．４〜０．６の範囲となるように配合してもよい。
【００１８】
本発明において、上記エポキシ樹脂の硬化促進剤（反応促進剤）（ｃ）としては、イミダゾール化合物や有機リン化合物等、特にイミダゾール化合物又は有機リン化合物等を含有したマイクロカプセル触媒であって、平均粒径が０．５〜１０μｍであり、かつｏ−クレゾール中におけるマイクロカプセルからの触媒の溶出量が３０℃、１５分でマイクロカプセル中に含まれる全触媒量の７０重量％以上であるマイクロカプセル触媒を用いることが好ましい。
【００１９】
ここで、イミダゾール化合物としては、下記一般式（１）で示されるものを使用することができる。
【化３】

（Ｒ⁵、Ｒ⁶は−Ｈ、−ＣＨ₃、−Ｃ₂Ｈ₅、−ＣＨ₂ＯＨ又は−Ｃ₆Ｈ₅であり、Ｒ⁷は−ＣＨ₃、−Ｃ₂Ｈ₅、−Ｃ₆Ｈ₅、又はアリル基であり、Ｒ⁸は−Ｈ、−ＣＨ₃、−Ｃ₂Ｈ₅、及び下記式（２）
【化４】

で表される基から選ばれる基である。）
【００２０】
イミダゾール化合物として、具体的には、２−メチルイミダゾール、２−エチルイミダゾール、２−ウンデシルイミダゾール、２，４−ジメチルイミダゾール、２−ヘプタデシルイミダゾール、１，２−ジメチルイミダゾール、１，２−ジエチルイミダゾール、２−エチル−４−メチルイミダゾール、２−フェニルイミダゾール、１−ベンジル−２−フェニルイミダゾール、１−シアノエチル−２−メチルイミダゾール、１−シアノエチル−２−ウンデシルイミダゾール、１−ベンジル−２−メチルイミダゾール、２，４−ジアミノ−６−［２’−メチルイミダゾリル−（１）’］−エチル−Ｓ−トリアジン、２，４−ジアミノ−６−［２’−エチル−４’−メチルイミダゾリル−（１）’］−エチル−Ｓ−トリアジン、２，４−ジアミノ−６−［２’−ウンデシルイミダゾリル］−エチル−Ｓ−トリアジン、２，４−ジアミノ−６−［２’−メチルイミダゾリル−（１）’］−エチル−Ｓ−トリアジンイソシアヌール酸化付加物、２−フェニル−４−メチル−５−ヒドロキシメチルイミダゾール、２−フェニル−４，５−ジヒドロキシメチルイミダゾール、２−アリール−４，５−ジフェニルイミダゾールなどが挙げられる。これらの中でも２−メチルイミダゾール、２−エチルイミダゾール、１，２−ジメチルイミダゾール、１，２−ジエチルイミダゾール、２−エチル−４−メチルイミダゾール、２−ウンデシルイミダゾール、２−ヘプタデシルイミダゾール及び２−フェニルイミダゾールが好ましい。
【００２１】
有機リン系化合物としては、例えば、トリフェニルフォスフィン、トリブチルホスフィン、トリ（ｐ−メチルフェニル）ホスフィン、トリ（ノニルフェニル）ホスフィン、ジフェニルトリルフォスフィン等のトリオルガノホスフィンとトリオルガノボランとの塩、テトラフェニルフォスホニウム・テトラフェニルボレート等のテトラオルガノホスホニウムとテトラオルガノボレートとの塩などが挙げられる。これらの中でも下記一般式（３）、（４）及び（５）で示されるものが好ましく、特に下記一般式（４）及び（５）で示されるものが好ましい。
【００２２】
【化５】

Ｒ¹Ｒ²Ｒ³Ｒ⁴ＰＳＣＮ （４）
Ｒ¹Ｒ²Ｒ³Ｒ⁴Ｐ：ＢＲ¹Ｒ²Ｒ³Ｒ⁴ （５）
（但し、Ｒ⁹は、水素原子又は炭素数１〜４のアルキル基であり、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴は、炭素数１〜２０の有機基である。）
【００２３】
ここで、式中のＲ⁹としては、好ましくは水素原子又はメチル基である。Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴の炭素数１〜２０、特に１〜６の有機基としては、メチル基、エチル基、プロピル基、ブチル基、メトキシ基、エトキシエチル基等のアルキル基、ビニル基、アリル基、イソプロペニル基等のアルケニル基、フェニル基等のアリール基、アセチル基、プロピオニル基等や、これらの炭化水素基の水素原子の一部又は全部を塩素、フッ素、臭素等のハロゲン原子で置換したフロロメチル基、ブロモエチル基、トリフルオロプロピル基等のハロゲン置換一価炭化水素基などが例示される。
【００２４】
本発明で使用するマイクロカプセルは、（メタ）アクリル系単量体、例えばアクリル酸エステル、イタコン酸エステル、クロトン酸エステル等の炭素数１〜８のアルキルエステルやこのアルキルエステルのアルキル基がアリル基等の置換基を有するもの、また、スチレン、α−メチルスチレン、アクリロニトリル、メタクリロニトリル、酢酸ビニル等の単官能性単量体及びエチレングリコールジ（メタ）アクリレート、ポリエチレングリコールジ（メタ）アクリレート、ジビニルベンゼン、ビスフェノールＡジ（メタ）アクリレート、メチレンビス（メタ）アクリルアミド等の多官能単量体のポリマー中に硬化触媒が閉じ込められたものである。なお、上記ポリマーの中では、（メタ）アクリレート系単量体の重合物が好ましい。
【００２５】
本発明の上記イミダゾール化合物又は有機リン化合物等の硬化触媒を含有するマイクロカプセルの製造方法としては様々な方法が挙げられるが、生産性及び球状度が高いマイクロカプセルを製造するためには、通常懸濁重合法及び乳化重合法などの従来から公知の方法で製造することができる。
【００２６】
この場合、一般的に使用されている触媒の分子構造から高濃度マイクロカプセル触媒を得るためには、硬化触媒１０重量部に対して使用する上記単量体の総量は１０〜２００重量部程度が好ましく、より好ましくは１０〜１００重量部、更に好ましくは２０〜５０重量部である。１０重量部未満では潜在性を十分に寄与することが困難となることがあり、２００重量部を超えると、触媒の比率が低くなり、十分な硬化性を得るためには多量に使用しなければならなくなるため、経済的に不利となる場合がある。
【００２７】
このような方法で得られるマイクロカプセルとしては、平均粒径が０．５〜１０μｍ、最大粒径が５０μｍ以下のものを使用することが好ましい。より好ましくは平均粒径が２〜５μｍ、かつ最大粒径が２０μｍ以下のものが好ましい。硬化促進剤の粒径が小さすぎると、比表面積が大きくなり、混合した時の粘度が高くなるおそれがある。平均粒径が１０μｍを超えると、樹脂への分散が不均一になり、信頼性の低下を引き起こすおそれがある。
【００２８】
また、上記マイクロカプセルとしては、下記性能を有するものを使用することが好ましい。即ち、硬化触媒を含有するマイクロカプセルを１ｇ秤量し、これをｏ−クレゾール３０ｇに混合した後、３０℃で放置し、溶出する触媒をガスクロマトグラフィーで定量した場合、マイクロカプセルから溶出する触媒が３０℃、１５分でマイクロカプセル中に含まれる全触媒量の７０重量％以上であるものを用いる。７０重量％未満では、硬化時間が長くかかるおそれがあり、生産性が低下する場合がある。望ましくは、溶出量が７５重量％以上である。
【００２９】
上記本発明のマイクロカプセル型硬化促進剤の配合量は、エポキシ樹脂１００重量部に対して０．５〜１０重量部、特に１〜７重量部であることが好ましい。０．５重量部未満では硬化性が低下するおそれがあり、１０重量部を超える量では硬化性に優れるが、半田接続時に半田が溶融接続する前にアンダーフィル材が硬化し、上手く半田接続がいかなかったり、保存性が低下するおそれがある。
【００３０】
また、硬化促進剤として、マイクロカプセル化しない上述の触媒を上記マイクロカプセル触媒と併用添加してもよい。その場合の配合量は、マイクロカプセル触媒としていない触媒の合計がエポキシ樹脂１００重量部に対して０．１〜１０重量部、望ましくは０．３〜７重量部であることが好ましい。０．１重量部未満では硬化性が低下するおそれがあり、１０重量部を超える量では硬化性に優れるが半田接続時に半田が溶融接続する前にアンダーフィル材が硬化し、上手く半田接続がいかなかったり、保存性が低下するおそれがある。
【００３１】
更に、マイクロカプセル化しない上述の触媒を単独で使用してもよい。その場合の配合量は、エポキシ樹脂１００重量部に対して０．１〜７重量部、望ましくは０．３〜５重量部である。０．１重量部未満では硬化性が低下するおそれがあり、７重量部を超える量では硬化性に優れるが、半田接続時に半田が溶融接続する前にアンダーフィル材が硬化し、上手く半田接続がいかなかったり、保存性が低下するおそれがある。
【００３２】
本発明の特徴的成分である（ｄ）半田接続用のフラックスは、アビエチン酸である。アビエチン酸は、下記に示すものである。
【化６】

【００３３】
上記式で示される添加剤の添加量は、樹脂成分［（ａ），（ｂ）成分］の合計１００重量部に対して０．５〜５重量部であり、好ましくは１〜３重量部である。０．５重量部未満であると、硬化物特性は問題ないが、半田接続に必要な酸化膜を除去できず、十分なフラックス効果が得られない。一方、５重量部を超える量になると半田接続性は問題ないが、硬化物特性、特に硬化性、密着性が低下する。
【００３４】
本発明の液状エポキシ樹脂組成物において、上記添加剤の混合方法は、特に限定されるものではないが、エポキシ樹脂、あるいは硬化剤と予め溶融混合し、均一に分散させることが望ましい。
【００３５】
一方、膨張係数を下げるため、無機質充填剤を半田接続の妨げにならない程度用いてもよい。無機質充填剤としては、従来より知られている各種の無機質充填剤を添加することができる。具体的に無機質充填剤としては、溶融シリカ、結晶シリカ、アルミナ、ボロンナイトライド、チッカアルミ、チッカ珪素、マグネシア、マグネシウムシリケート、アルミニウムなどが挙げられる。中でも真球状の溶融シリカが低粘度化のため望ましい。
上記無機質充填剤の粒径の大きさとしては、フリップチップギャップ幅（基板と半導体チップとの隙間）に対して平均粒径が約１／１０以下、最大粒径が１／２以下のものが好ましい。
【００３６】
無機質充填剤の配合量としては、エポキシ樹脂１００重量部に対して５０〜４００重量部で配合することが好ましく、望ましくは１００〜２５０重量部の範囲で配合することが好ましい。５０重量部未満では、膨張係数が大きく、冷熱試験においてクラックの発生を誘発させるおそれがある。４００重量部を超えると、粘度が高くなったり、半田接続時に半田と基板の間に入り、抵抗値の増大による導電性の低下をもたらすおそれがある。
【００３７】
本発明のエポキシ樹脂組成物には、応力を低下させる目的でシリコーンゴム、シリコーンオイルや液状のポリブタジエンゴム、メタクリル酸メチル−ブタジエン−スチレンよりなる熱可塑性樹脂などを配合してもよい。好ましくは、アルケニル基含有エポキシ樹脂又はフェノール樹脂のアルケニル基と下記平均組成式（６）で示される１分子中の珪素原子の数が２０〜４００であり、ＳｉＨ基の数が１〜５であるオルガノポリシロキサンのＳｉＨ基との付加反応により得られる共重合体を配合することが好ましい。
Ｈ_aＲ_bＳｉＯ_(4-a-b)/2 （６）
（但し、式中Ｒは置換又は非置換の一価の炭化水素基、ａは０．０１〜０．１、ｂは１．８〜２．２、１．８１≦ａ＋ｂ≦２．３である。）
【００３８】
なお、Ｒの一価炭化水素基としては、炭素数１〜１０、特に１〜８のものが好ましく、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔｅｒｔ−ブチル基、ヘキシル基、オクチル基、デシル基等のアルキル基、ビニル基、アリル基、プロペニル基、ブテニル基、ヘキセニル基等のアルケニル基、フェニル基、キシリル基、トリル基等のアリール基、ベンジル基、フェニルエチル基、フェニルプロピル基等のアラルキル基などや、これらの炭化水素基の水素原子の一部又は全部を塩素、フッ素、臭素等のハロゲン原子で置換したフロロメチル基、ブロモエチル基、トリフルオロプロピル基等のハロゲン置換一価炭化水素基を挙げることができる。
【００３９】
上記共重合体としては、中でも下記構造のものが望ましい。
【化７】

【００４０】
上記式中、Ｒは上記と同じであり、Ｒ¹⁰は水素原子又は炭素数１〜４のアルキル基であり、Ｒ¹¹は−ＣＨ₂ＣＨ₂ＣＨ₂−、−ＯＣＨ₂−ＣＨ（ＯＨ）−ＣＨ₂−Ｏ−ＣＨ₂ＣＨ₂ＣＨ₂−又は−Ｏ−ＣＨ₂ＣＨ₂ＣＨ₂−である。ｎは４〜１９９、好ましくは１９〜９９の整数、ｐは１〜１０の整数、ｑは１〜１０の整数である。
【００４１】
上記共重合体をジオルガノポリシロキサン単位がエポキシ樹脂１００重量部に対して０〜２０重量部、特には２〜１５重量部含まれるように配合することで応力をより一層低下させることができる。
【００４２】
本発明のエポキシ樹脂組成物には、更に必要に応じ、接着向上用炭素官能性シラン、カーボンブラックなどの顔料、染料、酸化防止剤、表面処理剤（γ−グリシドキシプロピルトリメトキシシランなど）、その他の添加剤を本発明の目的を損なわない範囲で配合することができる。
【００４３】
本発明のエポキシ樹脂組成物は、例えば、（ａ）エポキシ樹脂、（ｂ）硬化剤、（ｃ）硬化促進剤、（ｄ）添加剤及びその他の成分を同時に又は別々に、必要により加熱処理を加えながら撹拌、溶解、混合、分散させることにより得ることができる。これらの混合、撹拌、分散等の装置としては、特に限定されるものではないが、撹拌、加熱装置を備えたライカイ機、３本ロール、ボールミル、プラネタリーミキサー等を用いることができる。またこれら装置を適宜組み合わせて使用してもよい。
【００４４】
なお、本発明において、封止材として用いる液状エポキシ樹脂組成物の粘度は、２５℃において１０，０００ポイズ以下、特に１００〜８，０００ポイズのものが好ましい。また、この組成物の成形方法、成形条件は、常法とすることができるが、好ましくは、先に１００〜１２０℃、０．５時間以上、その後１５０℃、０．５時間以上の条件で熱オーブンキュアを行う。１００〜１２０℃での加熱が０．５時間未満では、硬化後にボイドが発生する場合がある。１５０℃での加熱が０．５時間未満では、十分な硬化物特性が得られない場合がある。
【００４５】
ここで、本発明に用いるフリップチップ型半導体装置としては、例えば図１に示したように、通常有機基板１の配線パターン面に複数個のバンプ２を介して半導体チップ３が搭載されているものであり、上記有機基板１と半導体チップ３との隙間（バンプ２間の隙間）にアンダーフィル材４が充填され、その側部がフィレット材５で封止されたものとすることができる。
【００４６】
【実施例】
以下、実施例及び比較例を示して本発明を詳細に説明するが、本発明は下記の実施例に制限されるものではない。
【００４７】
［実施例１，２、比較例１〜５］
表１で示す成分を３本ロールで均一に混練することにより、７種の樹脂組成物を得た。これらの樹脂組成物を用いて、以下に示す試験を行った。その結果を表１に示す。
【００４８】
［粘度］
ＢＨ型回転粘度計を用いて４ｒｐｍの回転数で２５℃における粘度を測定した。
［ゲル化時間］
組成物のゲル化時間を１５０℃の熱板上で測定した。
［Ｔｇ（ガラス転移温度）、ＣＴＥ１（膨張係数）、ＣＴＥ２（膨張係数）］
５ｍｍ×５ｍｍ×１５ｍｍの硬化物試験片を用いて、ＴＭＡ（熱機械分析装置）により毎分５℃の速さで昇温した時のＴｇを測定した。また、以下の温度範囲の膨張係数を測定した。
ＣＴＥ１の温度範囲は５０〜８０℃、ＣＴＥ２の温度範囲は２００〜２３０℃である。
［導電テスト］
直径２００μｍの半田ボールが数個接続された１０ｍｍ×１０ｍｍの銅板を、アンダーフィル材を１００μｍ厚で被膜した銅板上にのせ、最大温度２００℃に設定したＩＲリフローで処理した後、銅板と銅板が導電通しているかを確認した。
［接着力テスト］
感光性ポリイミドをコートしたシリコンチップ上に上面の直径２ｍｍ、下面の直径５ｍｍ、高さ３ｍｍの円錐台形状の試験片を載せ、１５０℃で３時間硬化させた。硬化後、得られた試験片の剪断接着力を測定し、初期値とした。更に、硬化させた試験片をＰＣＴ（１２１℃／２．１ａｔｍ）で１６８時間吸湿させた後、接着力を測定した。いずれの場合も試験片の個数は５個で行い、その平均値を接着力として表記した。
［ＰＣＴ剥離テスト］
フリップチップボンダーを用いてポリイミドコートした１０ｍｍ×１０ｍｍのシリコンチップ（半田ボール設置済み）を３０ｍｍ×３０ｍｍのＢＴ基板上に滴下したノンフローアンダーフィル材の上に接続し、ＩＲリフロー最高温度２４０℃で半田ボール接続とノンフローアンダーフィル材を硬化させ、更に１５０℃で３時間硬化させてテストサンプルを作製した。このテストサンプルをＰＣＴ（１２１℃、２．１ａｔｍ）の環境下に置き、１６８時間後の剥離をＣ−ＳＡＭ（ＳＯＮＩＸ社製）で確認した。
［熱衝撃テスト］
フリップチップボンダーを用いてポリイミドコートした１０ｍｍ×１０ｍｍのシリコンチップ（半田ボール設置済み）を３０ｍｍ×３０ｍｍのＢＴ基板上に滴下したノンフローアンダーフィル材の上に接続し、ＩＲリフロー最高温度２４０℃で半田ボール接続とノンフローアンダーフィル材を硬化させ、更に１５０℃で３時間硬化させてテストサンプルを作製した。このテストサンプルを、−６５℃／３０分、１５０℃／３０分を１サイクルとし、２５０，５００，７５０サイクル後の剥離、クラックを確認した。
【００４９】
【表１】

【００５０】
成分：
ＲＥ３０３Ｓ−Ｌ：ビスフェノールＦ型エポキシ樹脂（日本化薬製）
ＭＨ７００：メチルテトラヒドロ無水フタル酸（新日本理化製）
ＹＨ３０７：３，４−ジメチル−６−（２−メチル−１−プロぺニル）−１，２，３，６−テトラハイドロフタル酸及び１−イソプロピル−４−メチル−バイサクロ［２．２．２］オクト−５−エン−２，３−ジカルボン酸の混合物（混合比率＝６：４）（油化シェルエポキシ製）
ＳＥ８ＦＣ：最大粒径２４μｍ以下、平均粒径６μｍの球状シリカ（徳山ソーダ製）
キュアゾールＣ₁₁Ｚ−ＰＷ：２−ウンデシルイミダゾール（四国化成製）
２Ｅ４ＭＺのマイクロカプセル：２Ｅ４ＭＺ（２−エチル−４−メチルイミダゾール、四国化成製）を２０重量％含有したメタクリル酸メチルの重合体，平均粒径が７μｍ，ｏ−クレゾール中で３０℃、１５分間の処理でマイクロカプセルから溶出する触媒の量は８７重量％
【００５１】
共重合体：
【化８】

【００５２】
【発明の効果】
本発明の液状エポキシ樹脂組成物は、半導体素子を基板に接続する際に、半田接続と同時に硬化させても、ボイドの発生がなく、シリコンチップの表面、特に感光性ポリイミド樹脂や窒化膜との密着性に優れ、ＰＣＴ（１２０℃／２．１ａｔｍ）などの高温多湿の条件下でも劣化せず、熱衝撃に対して優れており、特に大型ダイサイズの半導体装置の封止材として有効であり、この封止材を用いた半導体装置は非常に信頼性の高いものである。
【００５３】
【図面の簡単な説明】
【図１】本発明の封止材を用いたフリップチップ型半導体装置の一例を示す断面図である。
【符号の説明】
１ 有機基板
２ バンプ
３ 半導体チップ
４ アンダーフィル材
５ フィレット材[0001]
BACKGROUND OF THE INVENTION
The present invention is suitable for semiconductor sealing, has very good adhesion to the surface of a silicon chip (particularly photosensitive polyimide, nitride film), gives a highly moisture-resistant cured product, and is resistant to thermal shock. The present invention relates to a liquid epoxy resin composition that can be an excellent non-flow underfill material of a semiconductor device, and a flip-chip type semiconductor device sealed with a cured product of the non-flow underfill material.
[0002]
[Prior art and problems to be solved by the invention]
In the field of electronic materials, semiconductor devices adopting a flip-chip connection method are widely used as semiconductor devices are highly integrated, high performance, and light in weight. The flip-chip connection method uses a eutectic solder or the like between the element surface of the silicon chip and the organic substrate, and then uses a capillary phenomenon to penetrate the underfill material into the narrow part of the silicon chip and the substrate. By fixing the silicon chip, the silicon chip is fixed and the reliability is ensured. For this reason, demands for underfill materials are becoming increasingly sophisticated, centering on stress characteristics and moisture resistance characteristics. Particularly in flip chip connection, the expansion coefficient of silicon chip is 3 ppm / ° C. and the difference in expansion coefficient is 17 ppm / ° C. for organic substrates, etc., so that a very large shear stress is generated in the solder bump portion. This makes it possible to reduce the stress at the solder joint portion by injecting and curing an underfill material between the silicon chip and the substrate. Also, underfill materials are expected to be effective from the viewpoint of moisture resistance reliability and mechanical aspects.
[0003]
However, along with the high integration of semiconductor elements, there are cases where one side of the die size exceeds 10 mm and 20 mm, and the die size is increasing. In the flip chip type semiconductor device using such a large die, there is a problem that sufficient thin film penetration characteristics cannot be obtained even if the capillary phenomenon is used, and the film stops in the middle and becomes unfilled. Also, a prescription for reducing the filling material has been taken to obtain the thin film penetration characteristics, but since the expansion coefficient becomes small, the stress applied to the die and the sealing material during solder reflow increases, and the sealing material and the die and Problems such as peeling at the interface of the substrate and cracks in the package and sealing material have been highlighted.
[0004]
Furthermore, an underfill material (hereinafter referred to as a flow underfill material) using a capillary phenomenon takes a number of steps in the thin film intrusion process, which causes a cost increase. Therefore, Japanese Patent No. 2589239 proposes a prescription in which an underfill material mixed with a flux is dropped when a semiconductor element is connected to a substrate, and then the underfill material is cured simultaneously with solder connection. This assembly method eliminates the thin film intrusion step and is effective for significant cost reduction.
[0005]
However, the underfill material mixed with such a flux (hereinafter referred to as a non-flow underfill material) has insufficient adhesion to the surface of the silicon chip, particularly the photosensitive polyimide resin or nitride film, and cracks during solder reflow. As a result of this, peeling and cracking occur in the temperature cycle, there is a strong demand for improved reliability from the semiconductor industry. As such a current non-flow underfill material, a liquid epoxy resin is mainly used as a main component, and a phthalic anhydride acid anhydride or an amine curing agent is widely used as a curing agent. However, since phthalic anhydride acid anhydrides are easy to absorb moisture, before curing, there is a phenomenon that the penetration property varies due to the increase in viscosity due to moisture absorption or stops in the middle, and the conventional uncured acid anhydrides. Is a problem of reliability that easily absorbs water, promotes hydrolysis even after curing, causes volume expansion due to moisture absorption, and increases the resistance value between the solder bump and the lead interface in flip chip semiconductor devices, etc. Has occurred. Furthermore, with the flux material added and the main component of the flux, although the solder connectivity is good, a large amount of voids are generated at the time of connection curing, the curability is inferior, and the adhesion to the substrate is reduced. At present, most of the devices are not available, and a semiconductor device that can satisfy the reliability has not been obtained.
[0006]
The present invention has been made in view of the above circumstances, and provides a cured product excellent in adhesion with the surface of a silicon chip, particularly a photosensitive polyimide resin or a nitride film, and there is no cracking or peeling even after moisture-absorbing solder reflow. A semiconductor device that does not deteriorate even under high temperature and high humidity conditions such as PCT (120 ° C./2.1 atm) after the treatment, and does not peel or crack even if it exceeds several hundred cycles at a temperature cycle of −65 ° C./150° C. It is an object of the present invention to provide a liquid epoxy resin composition that can be a non-flow underfill material, and a flip chip type semiconductor device sealed with a cured product of the non-flow underfill material.
[0007]
Means for Solving the Problem and Embodiment of the Invention
As a result of intensive studies to achieve the above object, the present inventor is selected from (a) liquid epoxy resin, (b) curing agent, (c) curing accelerator, and (d) abietic acid and its derivatives. A seed or two or more additives are essential components, and the additive of component (d) is blended in an amount of 0.5 to 5 parts by weight with respect to 100 parts by weight of the total of components (a) and (b). Even when the liquid epoxy resin composition thus obtained is cured at the same time as the solder connection when the semiconductor element is connected to the substrate, the adhesion to the surface of the silicon chip, particularly to the photosensitive polyimide resin or nitride film, is improved. Knowledge that it is excellent, is not deteriorated under high-temperature and high-humidity conditions such as PCT (120 ° C / 2.1 atm), is excellent against thermal shock, and is particularly effective as a sealing material for large die size semiconductor devices. did.
[0008]
That is, abietic acid and its derivatives do not deteriorate the inherently latent characteristics of the underfill material, can be cured simultaneously with the solder connection, and the intrusion process can be reduced. The flip chip type semiconductor device encapsulated with a cured product of this composition is remarkably excellent in thermal shock resistance, and can obtain excellent characteristics even under high temperature and high humidity, especially under the large die size semiconductor device. It has been found that it is effective as a fill material and has led to the present invention.
[0009]
  Therefore, the present invention
(A) Liquid epoxy resin
(B)3,4-Dimethyl-6- (2-methyl-1-propenyl) -1,2,3,6-tetrahydrophthalic acid and 1-isopropyl-4-methyl-bisacro [2.2.2] oct A mixture of -5-ene-2,3-dicarboxylic acid and methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride or hexahydrophthalic anhydride are used in combination, and the mixture is added in an amount of 5 to 75% by weight of the entire curing agent. %containsHardener
(C) Curing accelerator
(D)Following formula
[Chemical 9]

Represented byAbietinacid
Is provided as an essential component, and the liquid epoxy resin composition is characterized in that the component (d) is contained in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the total of the components (a) and (b).
[0010]
Hereinafter, the present invention will be described in more detail.
In the semiconductor sealing material (liquid epoxy resin composition) of the present invention, (a) any liquid epoxy resin can be used as long as it has two or more epoxy groups in one molecule. A type epoxy resin, bisphenol type epoxy resin such as bisphenol F type epoxy resin, novolac type epoxy resin such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, cyclopentadiene type epoxy resin Etc. are exemplified. Among these, a liquid epoxy resin is desirable at room temperature. To these epoxy resins, there is no problem even if an epoxy resin represented by the following structure is added within a range that does not affect the penetration property.
[0011]
[Chemical 2]

[0012]
The total chlorine content in the liquid epoxy resin is preferably 1500 ppm or less, more preferably 1000 ppm or less. Moreover, it is preferable that the extraction water chlorine in 20 hours in the 50% epoxy resin density | concentration at 100 degreeC is 10 ppm or less. If the total chlorine content exceeds 1500 ppm or the extracted water chlorine exceeds 10 ppm, the reliability of the semiconductor element, particularly moisture resistance, may be adversely affected.
[0013]
The (b) curing agent used in the present invention is not particularly limited, but an acid anhydride curing agent is effective for improving reliability. Examples of the acid anhydride curing agent include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhymic anhydride, pyromellitic dianhydride, maleated alloocimene, and benzophenonetetracarboxylic acid diacid. Anhydride, 3,3 ′, 4,4′-biphenyltetrabisbenzophenonetetracarboxylic dianhydride, (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) methane Anhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,4-dimethyl-6- (2-methyl-1-propenyl) -1,2,3,6- Tetrahydrophthalic acid and 1-isopropyl-4-methyl-bisacro [2.2.2] oct-5-ene-2,3-dicarboxylic acid And mixtures thereof.
[0014]
In the present invention, in particular, 3,4-dimethyl-6- (2-methyl-1-propenyl) -1,2,3,6-tetrahydrophthalic acid and 1-isopropyl-4-methyl-bisacyclo [ 2.2.2] It is preferred to use a mixture of oct-5-ene-2,3-dicarboxylic acid. In addition, 3,4-dimethyl-6- (2-methyl-1-propenyl) -1,2,3,6-tetrahydrophthalic acid and 1-isopropyl-4-methyl-bisacro [2.2. 2] As a mixing ratio of oct-5-ene-2,3-dicarboxylic acid, it is desirable that the former is 20 to 60% by weight and the latter is 80 to 40% by weight (total 100% by weight).
Examples of such a curing agent include YH306 and YH307 manufactured by Yuka Shell Epoxy Co., Ltd.
[0015]
The blending ratio of the mixture in the curing agent is desirably 5 to 75% by weight, particularly 15 to 65% by weight, based on the entire curing agent. If it is less than 5% by weight, the adhesiveness is lowered and may deteriorate under high temperature and high humidity such as PCT. If the amount exceeds 75% by weight, the adhesion is improved, but cracks may occur in a test such as a thermal shock test.
[0016]
In this invention, it does not restrict | limit especially as a hardening | curing agent other than the above, The hardening | curing agent generally used for a curable epoxy resin composition can be used. Specific examples of the curing agent include carboxylic acid hydrazides such as the above-mentioned acid anhydrides in general, dicyandiamide, adipic hydrazide, and isophthalic hydrazide. Of these, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and hexahydrophthalic anhydride are particularly preferable. Therefore, the above 3,4-dimethyl-6- (2-methyl-1-propenyl) -1 is preferred. , 2,3,6-tetrahydrophthalic acid and 1-isopropyl-4-methyl-bisacro [2.2.2] oct-5-ene-2,3-dicarboxylic acid are methyltetrahydrophthalic anhydride, It is preferable to use in combination with methylhexahydrophthalic anhydride or hexahydrophthalic anhydride.
[0017]
The total blending amount of the curing agent used in the present invention is an effective amount for curing the epoxy resin, and differs depending on the type, but when using the acid anhydride described above, it is based on the epoxy group in the epoxy resin. The molar ratio of the carboxylic acid groups derived from the acid anhydride groups (—CO—O—CO—) in the curing agent is preferably in the range of 0.5 to 1.5. If it is less than 0.5, the curability is insufficient, and if it exceeds 1.5, unreacted acid anhydride remains, which may lower the glass transition temperature. A range of 0.8 to 1.2 is more preferable. Alternatively, for the same reason as described above, the molar ratio of the acid anhydride group in the acid anhydride to the epoxy group in the epoxy resin is preferably 0.3 to 0.7, more preferably 0.4 to 0.00. You may mix | blend so that it may become the range of 6.
[0018]
In the present invention, the curing accelerator (reaction accelerator) (c) of the epoxy resin is a microcapsule catalyst containing an imidazole compound or an organic phosphorus compound, particularly an imidazole compound or an organic phosphorus compound, and has an average particle size. A microcapsule catalyst having a diameter of 0.5 to 10 μm and an elution amount of the catalyst from the microcapsule in o-cresol of 70% by weight or more of the total catalyst amount contained in the microcapsule in 30 minutes at 30 ° C. Is preferably used.
[0019]
Here, what is shown by following General formula (1) can be used as an imidazole compound.
[Chemical Formula 3]

(R^Five, R⁶Are -H, -CH_Three, -C₂H_Five, -CH₂OH or -C₆H_FiveAnd R⁷Is -CH_Three, -C₂H_Five, -C₆H_FiveOr an allyl group and R⁸Are -H, -CH_Three, -C₂H_FiveAnd the following formula (2)
[Formula 4]

Is a group selected from the group represented by: )
[0020]
Specific examples of the imidazole compound include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2,4-dimethylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, and 1,2-diethyl. Imidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-benzyl-2- Methylimidazole, 2,4-diamino-6- [2'-methylimidazolyl- (1) ']-ethyl-S-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1) ']-Ethyl-S-triazine, 2,4-diamino- -[2'-undecylimidazolyl] -ethyl-S-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1) ']-ethyl-S-triazine isocyanurate oxidation adduct, 2- Examples include phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-aryl-4,5-diphenylimidazole and the like. Among these, 2-methylimidazole, 2-ethylimidazole, 1,2-dimethylimidazole, 1,2-diethylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole and 2- Phenylimidazole is preferred.
[0021]
Examples of the organophosphorus compounds include triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, diphenyltolylphosphine and the like triorganophosphine and triorganoborane salts. Examples thereof include salts of tetraorganophosphonium and tetraorganoborate such as tetraphenylphosphonium and tetraphenylborate. Among these, those represented by the following general formulas (3), (4) and (5) are preferred, and those represented by the following general formulas (4) and (5) are particularly preferred.
[0022]
[Chemical formula 5]

R¹R²R^ThreeR^FourPSCN (4)
R¹R²R^ThreeR^FourP: BR¹R²R^ThreeR^Four                (5)
(However, R⁹Is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R¹, R², R^Three, R^FourIs an organic group having 1 to 20 carbon atoms. )
[0023]
Where R in the formula⁹Is preferably a hydrogen atom or a methyl group. R¹, R², R^Three, R^FourExamples of the organic group having 1 to 20 carbon atoms, particularly 1 to 6 carbon atoms include alkyl groups such as methyl, ethyl, propyl, butyl, methoxy, and ethoxyethyl groups, vinyl groups, allyl groups, isopropenyl groups, and the like. Aryl groups such as alkenyl groups, phenyl groups and the like, acetyl groups, propionyl groups, and the like, and fluoromethyl groups and bromoethyl groups in which some or all of the hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms such as chlorine, fluorine, and bromine And halogen-substituted monovalent hydrocarbon groups such as a trifluoropropyl group.
[0024]
The microcapsule used in the present invention is a (meth) acrylic monomer, for example, an alkyl ester having 1 to 8 carbon atoms such as an acrylate ester, an itaconic acid ester or a crotonic acid ester, or an alkyl group of this alkyl ester is an allyl group. A monofunctional monomer such as styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, vinyl acetate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, A curing catalyst is confined in a polymer of a polyfunctional monomer such as divinylbenzene, bisphenol A di (meth) acrylate, or methylenebis (meth) acrylamide. In addition, in the said polymer, the polymer of a (meth) acrylate type monomer is preferable.
[0025]
There are various methods for producing a microcapsule containing a curing catalyst such as the imidazole compound or organophosphorus compound of the present invention. However, in order to produce a microcapsule with high productivity and high sphericity, it is usually a problem. It can be produced by a conventionally known method such as a turbid polymerization method or an emulsion polymerization method.
[0026]
In this case, in order to obtain a high-concentration microcapsule catalyst from the molecular structure of a commonly used catalyst, the total amount of the monomer used with respect to 10 parts by weight of the curing catalyst is about 10 to 200 parts by weight. The amount is preferably 10 to 100 parts by weight, more preferably 20 to 50 parts by weight. If the amount is less than 10 parts by weight, it may be difficult to sufficiently contribute the potential. If the amount exceeds 200 parts by weight, the ratio of the catalyst is lowered, and in order to obtain sufficient curability, a large amount must be used. This may be economically disadvantageous.
[0027]
As the microcapsules obtained by such a method, those having an average particle diameter of 0.5 to 10 μm and a maximum particle diameter of 50 μm or less are preferably used. More preferably, the average particle size is 2 to 5 μm and the maximum particle size is 20 μm or less. If the particle size of the curing accelerator is too small, the specific surface area increases and the viscosity when mixed may increase. When the average particle diameter exceeds 10 μm, dispersion in the resin becomes non-uniform, and there is a risk of causing a decrease in reliability.
[0028]
Moreover, it is preferable to use what has the following performance as said microcapsule. That is, 1 g of microcapsules containing a curing catalyst are weighed, mixed with 30 g of o-cresol, and then left at 30 ° C. When the eluted catalyst is quantified by gas chromatography, the catalyst eluted from the microcapsule is What is 70 weight% or more of the total catalyst amount contained in a microcapsule in 30 degreeC and 15 minutes is used. If it is less than 70% by weight, the curing time may take longer, and the productivity may decrease. Desirably, the elution amount is 75% by weight or more.
[0029]
The blending amount of the microcapsule type curing accelerator of the present invention is preferably 0.5 to 10 parts by weight, particularly 1 to 7 parts by weight with respect to 100 parts by weight of the epoxy resin. If the amount is less than 0.5 parts by weight, the curability may be reduced. If the amount exceeds 10 parts by weight, the curability is excellent. However, the solder fills before the solder melts and the underfill material cures, and the solder connection is successful. There is a risk that it will not go or the storage stability will deteriorate.
[0030]
Further, as the curing accelerator, the above-mentioned catalyst that is not microencapsulated may be added in combination with the microcapsule catalyst. In this case, the total amount of the catalyst not used as the microcapsule catalyst is 0.1 to 10 parts by weight, preferably 0.3 to 7 parts by weight with respect to 100 parts by weight of the epoxy resin. If the amount is less than 0.1 parts by weight, the curability may be lowered. If the amount exceeds 10 parts by weight, the curability is excellent. However, the solder fills before the solder melts at the time of solder connection, and the solder connection is successful. There is a risk that storage stability may be reduced.
[0031]
Furthermore, the above-mentioned catalyst that is not microencapsulated may be used alone. The compounding quantity in that case is 0.1-7 weight part with respect to 100 weight part of epoxy resins, Preferably it is 0.3-5 weight part. If the amount is less than 0.1 parts by weight, the curability may be lowered. If the amount exceeds 7 parts by weight, the curability is excellent. However, the solder fills before the solder melts and the underfill material cures, and the solder connection is successful. There is a risk that it will not go or the storage stability will deteriorate.
[0032]
  (D) The flux for solder connection, which is a characteristic component of the present invention, is abietic acid.sois there. Abietic acidIs, As shown belowInThe
[Chemical 6]

[0033]
  the aboveformulaThe amount of the additive represented by is 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the total of the resin components [components (a) and (b)]. If it is less than 0.5 parts by weight, there is no problem with the cured product characteristics, but the oxide film necessary for solder connection cannot be removed, and a sufficient flux effect cannot be obtained. On the other hand, when the amount exceeds 5 parts by weight, there is no problem in solder connectivity, but cured product characteristics, particularly curability and adhesion, are deteriorated.
[0034]
In the liquid epoxy resin composition of the present invention, the method for mixing the above additives is not particularly limited, but it is desirable to melt and mix in advance with an epoxy resin or a curing agent and uniformly disperse.
[0035]
On the other hand, in order to lower the expansion coefficient, an inorganic filler may be used as long as it does not hinder solder connection. As the inorganic filler, conventionally known various inorganic fillers can be added. Specific examples of the inorganic filler include fused silica, crystalline silica, alumina, boron nitride, ticker aluminum, ticker silicon, magnesia, magnesium silicate, aluminum and the like. Among them, spherical fused silica is desirable for reducing the viscosity.
As for the particle size of the inorganic filler, the average particle size is about 1/10 or less and the maximum particle size is 1/2 or less with respect to the flip chip gap width (gap between the substrate and the semiconductor chip). preferable.
[0036]
As a compounding quantity of an inorganic filler, it is preferable to mix | blend in 50-400 weight part with respect to 100 weight part of epoxy resins, It is preferable to mix | blend in the range of 100-250 weight part desirably. If it is less than 50 parts by weight, the expansion coefficient is large and there is a risk of inducing the occurrence of cracks in the cold test. If it exceeds 400 parts by weight, the viscosity may increase, or the solder may enter between the solder and the substrate during solder connection, resulting in a decrease in conductivity due to an increase in resistance.
[0037]
The epoxy resin composition of the present invention may be blended with silicone rubber, silicone oil, liquid polybutadiene rubber, thermoplastic resin made of methyl methacrylate-butadiene-styrene, or the like for the purpose of reducing stress. Preferably, the alkenyl group of the alkenyl group-containing epoxy resin or phenol resin and the number of silicon atoms in one molecule represented by the following average composition formula (6) are 20 to 400, and the number of SiH groups is 1 to 5. It is preferable to blend a copolymer obtained by addition reaction with the SiH group of the organopolysiloxane.
H_aR_bSiO_{(4-ab) / 2}                          (6)
Wherein R is a substituted or unsubstituted monovalent hydrocarbon group, a is 0.01 to 0.1, b is 1.8 to 2.2, and 1.81 ≦ a + b ≦ 2.3. .)
[0038]
As the monovalent hydrocarbon group for R, those having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms are preferable, and a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, Hexyl group, octyl group, decyl group and other alkyl groups, vinyl group, allyl group, propenyl group, butenyl group, hexenyl group and other alkenyl groups, phenyl group, xylyl group, tolyl group and other aryl groups, benzyl group, phenylethyl Groups, aralkyl groups such as phenylpropyl groups, etc., and fluorocarbon groups, bromoethyl groups, trifluoropropyl groups, etc. in which some or all of the hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms such as chlorine, fluorine, bromine, etc. Mention may be made of halogen-substituted monovalent hydrocarbon groups.
[0039]
Among the above copolymers, those having the following structures are desirable.
[Chemical 7]

[0040]
In the above formula, R is the same as above, and R^TenIs a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R¹¹Is -CH₂CH₂CH₂-, -OCH₂-CH (OH) -CH₂-O-CH₂CH₂CH₂-Or -O-CH₂CH₂CH₂-. n is an integer of 4 to 199, preferably 19 to 99, p is an integer of 1 to 10, and q is an integer of 1 to 10.
[0041]
The stress can be further reduced by blending the copolymer so that the diorganopolysiloxane unit is contained in an amount of 0 to 20 parts by weight, particularly 2 to 15 parts by weight, based on 100 parts by weight of the epoxy resin.
[0042]
In the epoxy resin composition of the present invention, if necessary, a pigment such as carbon functional silane for improving adhesion, carbon black and other pigments, dyes, antioxidants, surface treatment agents (γ-glycidoxypropyltrimethoxysilane, etc.) Further, other additives can be blended within a range not impairing the object of the present invention.
[0043]
The epoxy resin composition of the present invention is, for example, (a) an epoxy resin, (b) a curing agent, (c) a curing accelerator, (d) an additive and other components simultaneously or separately, and if necessary, heat treatment. It can be obtained by stirring, dissolving, mixing and dispersing while adding. The apparatus for mixing, stirring, dispersing and the like is not particularly limited, and a lykai machine, a three roll, a ball mill, a planetary mixer and the like equipped with a stirring and heating device can be used. Moreover, you may use combining these apparatuses suitably.
[0044]
In the present invention, the viscosity of the liquid epoxy resin composition used as the sealing material is preferably 10,000 poise or less, particularly 100 to 8,000 poise at 25 ° C. The molding method and molding conditions of this composition can be conventional methods, but preferably, the conditions are 100 to 120 ° C. for 0.5 hour or longer, and then 150 ° C. for 0.5 hour or longer. Perform a heat oven cure. When heating at 100 to 120 ° C. is less than 0.5 hour, voids may occur after curing. If the heating at 150 ° C. is less than 0.5 hour, sufficient cured product characteristics may not be obtained.
[0045]
Here, as a flip chip type semiconductor device used in the present invention, for example, as shown in FIG. 1, a semiconductor chip 3 is usually mounted on a wiring pattern surface of an organic substrate 1 via a plurality of bumps 2. The underfill material 4 is filled in the gap between the organic substrate 1 and the semiconductor chip 3 (the gap between the bumps 2), and the side portion thereof is sealed with the fillet material 5.
[0046]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example.
[0047]
    Example 1, 2,Comparative Examples 1-5]
  Seven types of resin compositions were obtained by uniformly kneading the components shown in Table 1 with three rolls. The test shown below was done using these resin compositions. The results are shown in Table 1.
[0048]
[viscosity]
The viscosity at 25 ° C. was measured at a rotation speed of 4 rpm using a BH type rotational viscometer.
[Gelification time]
The gel time of the composition was measured on a hot plate at 150 ° C.
[Tg (glass transition temperature), CTE1 (expansion coefficient), CTE2 (expansion coefficient)]
Using a cured product test piece of 5 mm × 5 mm × 15 mm, Tg was measured when the temperature was raised at a rate of 5 ° C. per minute by TMA (thermomechanical analyzer). Moreover, the expansion coefficient in the following temperature range was measured.
The temperature range of CTE1 is 50 to 80 ° C, and the temperature range of CTE2 is 200 to 230 ° C.
[Conductivity test]
A 10 mm × 10 mm copper plate connected with several 200 μm diameter solder balls is placed on a copper plate coated with an underfill material with a thickness of 100 μm and treated by IR reflow set at a maximum temperature of 200 ° C. It was confirmed whether it was conductive.
[Adhesion test]
A test piece in the shape of a truncated cone having a diameter of 2 mm on the upper surface, a diameter of 5 mm on the lower surface and a height of 3 mm was placed on a silicon chip coated with photosensitive polyimide and cured at 150 ° C. for 3 hours. After curing, the shear strength of the obtained test piece was measured and used as the initial value. Further, the cured test piece was absorbed with PCT (121 ° C./2.1 atm) for 168 hours, and then the adhesive strength was measured. In any case, the number of test pieces was five, and the average value was expressed as adhesive strength.
[PCT peel test]
Using a flip chip bonder, a polyimide-coated 10 mm x 10 mm silicon chip (with solder balls installed) is connected onto a non-flow underfill material dropped onto a 30 mm x 30 mm BT substrate, and the IR reflow maximum temperature is 240 ° C. The solder ball connection and the non-flow underfill material were cured and further cured at 150 ° C. for 3 hours to prepare a test sample. This test sample was placed in an environment of PCT (121 ° C., 2.1 atm), and peeling after 168 hours was confirmed by C-SAM (manufactured by SONIX).
[Thermal shock test]
Using a flip chip bonder, a polyimide-coated 10 mm x 10 mm silicon chip (with solder balls installed) is connected onto a non-flow underfill material dropped onto a 30 mm x 30 mm BT substrate, and the IR reflow maximum temperature is 240 ° C. The solder ball connection and the non-flow underfill material were cured and further cured at 150 ° C. for 3 hours to prepare a test sample. For this test sample, −65 ° C./30 minutes and 150 ° C./30 minutes were taken as one cycle, and peeling and cracking after 250,500,750 cycles were confirmed.
[0049]
[Table 1]

[0050]
component:
RE303S-L: Bisphenol F type epoxy resin (manufactured by Nippon Kayaku)
MH700: Methyltetrahydrophthalic anhydride (manufactured by Nippon Nippon Chemical Co., Ltd.)
YH307: 3,4-dimethyl-6- (2-methyl-1-propenyl) -1,2,3,6-tetrahydrophthalic acid and 1-isopropyl-4-methyl-bisacro [2.2.2 ] Octo-5-ene-2,3-dicarboxylic acid mixture (mixing ratio = 6: 4) (made by oil-coated shell epoxy)
SE8FC: Spherical silica with a maximum particle size of 24 μm or less and an average particle size of 6 μm (manufactured by Tokuyama Soda)
Curezol C₁₁Z-PW: 2-undecylimidazole (manufactured by Shikoku Chemicals)
2E4MZ microcapsules: a polymer of methyl methacrylate containing 20% by weight of 2E4MZ (2-ethyl-4-methylimidazole, manufactured by Shikoku Kasei), average particle size of 7 μm, in o-cresol at 30 ° C. for 15 minutes The amount of catalyst eluted from the microcapsules during the treatment is 87% by weight
[0051]
Copolymer:
[Chemical 8]

[0052]
【The invention's effect】
The liquid epoxy resin composition of the present invention does not generate voids even when it is cured simultaneously with soldering when connecting a semiconductor element to a substrate, and the surface of the silicon chip, particularly with a photosensitive polyimide resin or nitride film Excellent adhesion, does not deteriorate under high temperature and high humidity conditions such as PCT (120 ° C / 2.1 atm), is excellent against thermal shock, and is particularly effective as a sealing material for large die size semiconductor devices A semiconductor device using this sealing material is extremely reliable.
[0053]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a flip chip type semiconductor device using a sealing material of the present invention.
[Explanation of symbols]
1 Organic substrate
2 Bump
3 Semiconductor chip
4 Underfill material
5 Fillet material

Claims (7)

(A) Liquid epoxy resin (b) 3,4-dimethyl-6- (2-methyl-1-propenyl) -1,2,3,6-tetrahydrophthalic acid and 1-isopropyl-4-methyl- A mixture of bisacuro [2.2.2] oct-5-ene-2,3-dicarboxylic acid and methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride or hexahydrophthalic anhydride, and the mixture the curing agent total 5-75 wt% containing curing agent (c) curing accelerator (d) the following formula

The essential component is abietic acid represented by the formula: Liquid epoxy resin composition. The curing accelerator is an imidazole compound or a liquid epoxy resin composition according to claim 1, wherein the organic phosphorus compound. The imidazole compound is 2-methylimidazole, 2-ethylimidazole, 1,2-dimethylimidazole, 1,2-diethylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole or The liquid epoxy resin composition according to claim 2, which is 2-phenylimidazole. The organophosphorus compound is represented by the following formula (4) or (5)
R ¹ R ² R ³ R ⁴ PSCN (4)
R ¹ R ² R ³ R ⁴ P: BR ¹ R ² R ³ R ⁴ (5)
(However, R ¹ , R ² , R ³ and R ⁴ are organic groups having 1 to 20 carbon atoms.)
The liquid epoxy resin composition according to claim 2, which is represented by:   Furthermore, the liquid epoxy resin composition of any one of Claims 1 thru | or 4 containing an inorganic filler. Further, the alkenyl group of the alkenyl group-containing epoxy resin or phenol resin and the following average composition formula (6)
H _a R _b SiO _{(4-ab) / 2} (6)
Wherein R is a substituted or unsubstituted monovalent hydrocarbon group, a is 0.01 to 0.1, b is 1.8 to 2.2, and 1.81 ≦ a + b ≦ 2.3. .)
The copolymer obtained by addition reaction with SiH group of organopolysiloxane whose number of silicon atoms in 1 molecule shown by these is 20-400, and the number of SiH groups is 1-5 is contained. The liquid epoxy resin composition of any one of thru | or 5. A flip-chip type semiconductor device that is sealed and thermally cured simultaneously with solder connection with the liquid epoxy resin composition according to any one of claims 1 to 6 .

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