JP4617532B2 - Epoxy resin composition and semiconductor device - Google Patents

Description

（式中、Ｒ¹は水素原子、炭素数１〜６の鎖状もしくは環状アルキル基、フェニル基、又はハロゲンの中から選択される基又は原子であり、互いに同一であっても異なっていてもよい。）
【０００７】
【化６】

（式中、Ｒ²は水素原子、炭素数１〜６の鎖状もしくは環状アルキル基、フェニル基、又はハロゲンの中から選択される基又は原子であり、互いに同一であっても異なっていてもよい。）
【０００８】
【化７】

（式中、Ｒ3〜Ｒ¹⁰は、それぞれ独立に、水素原子、炭素数１〜６の鎖状もしくは環状アルキル基、又はハロゲンの中から選択される基又は原子を示す。ただし、炭素−炭素二重結合に結合している２個のアリール基は互いに異なる。）
【０００９】
【化８】

（式中、Ｒ¹¹〜Ｒ¹⁴は、それぞれ独立に、水素原子、炭素数１〜６の鎖状もしくは環状アルキル基、又はハロゲンの中から選択される基又は原子を示す。ただし、炭素−炭素二重結合に結合している２個のアリール基は互いに同じである。
）
一般式（１）で示されるビフェニル型エポキシ樹脂の置換基Ｒ¹、及び一般式（２）で示されるビスフェノール型エポキシ樹脂の置換基Ｒ²は、水素原子、炭素数１〜６の鎖状もしくは環状アルキル基、フェニル基、又はハロゲンの中から選択される基又は原子であり、互いに同じであっても異なっていてもよく、例えば、メチル基、エチル基、プロピル基、ブチル基、シクロヘキシル基、フェニル基、塩素原子、臭素原子等が挙げられ、特にメチル基が好ましい。
一般式（３）、及び一般式（４）で示されるスチルベン型エポキシ樹脂の置換基Ｒ³〜Ｒ¹⁴は、水素原子、炭素数１〜６の鎖状もしくは環状アルキル基、又はハロゲンの中から選択される基又は原子であり、互いに同一であっても異なっていてもよく、例えば、水素原子、メチル基、エチル基、プロピル基、ブチル基、アミル基、ヘキシル基（各異性体を含む）、シクロヘキシル基、塩素原子、臭素原子等が挙げられ、特に、エポキシ樹脂の溶融粘度の低さから、メチル基、エチル基、プロピル基、又はブチル基が好ましい。
【００１０】
一般式（３）のスチルベン型エポキシ樹脂と一般式（４）のスチルベン型エポキシ樹脂との混合においては、両方の化合物を混合することにより融点が低くなればよく、混合方法については特に限定しない。例えば、スチルベン型エポキシ樹脂の原料であるスチルベン型フェノール類をグリシジルエーテル化する前に混合しておいたり、両方のスチルベン型エポキシ樹脂を溶融混合する方法等があるが、いずれの場合においても融点は５０〜１５０℃となるように調整する。一般式（３）のスチルベン型エポキシ樹脂及び一般式（４）のスチルベン型エポキシ樹脂には、共に置換基の種類等により種々の構造のものがあり、それぞれ１種類ずつ混合しても、２種類以上ずつ混合してもかまわない。
一般式（３）のスチルベン型エポキシ樹脂としては、入手のし易さ、性能、原料価格の点から、５−ターシャリブチル−４，４’−ジヒドロキシ−２，３’，５’−トリメチルスチルベン、３−ターシャリブチル−４，４’−ジヒドロキシ−３’，５，５’−トリメチルスチルベンのグリシジルエーテル化物が特に好ましい。
一般式（４）のスチルベン型エポキシ樹脂としては、性能、原料価格の点から、４，４’−ジヒドロキシ−３，３’，５，５’−テトラメチルスチルベン、４，４’−ジヒドロキシ−３，３’−ジターシャリブチル−６，６’−ジメチルスチルベン、４，４’−ジヒドロキシ−３，３’−ジターシャリブチル−５，５’−ジメチルスチルベンのグリシジルエーテル化物が特に好ましい。
【００１１】
本発明に用いられるフェノール樹脂は、１分子内に２個以上のフェノール性水酸基を有するモノマー、オリゴマー、及びポリマー全般を言う。例えば、フェノールノボラック樹脂、クレゾールノボラック樹脂、フェノールアラルキル樹脂、ナフトールアラルキル樹脂、テルペン変性フェノール樹脂、ジシクロペンタジエン変性フェノール樹脂等が挙げられ、これらは単独又は混合して用いてもよい。これらのフェノール樹脂は、分子量、軟化点、水酸基当量等に制限なく使用することができる。
これらのフェノール樹脂の内では、分子内の水酸基が少ないために成形品の吸水率が小さく、分子が適度の屈曲性を有するために硬化反応における反応性もよく、又低粘度化も可能であるということから、特に骨格にフェニレン、又はジフェニレン等を含むフェノールアラルキル樹脂が好ましい。
本発明に用いられる全エポキシ樹脂のエポキシ基と全フェノール樹脂のフェノール性水酸基の当量比は、好ましくは０．５〜２、特に好ましくは０．７〜１．５である。０．５〜２の範囲を外れると、硬化性、耐湿性等が低下するので好ましくない。
【００１２】
本発明に用いる分子化合物（Ｃ）は、テトラ置換ホスホニウム（Ｘ）と１分子内にフェノール性水酸基を２個以上有する化合物（Ｙ）及び１分子内にフェノール性水酸基を２個以上有する化合物（Ｙ）の共役塩基との分子会合体であって、該共役塩基が前記フェノール性水酸基を１分子内に２個以上有する化合物（Ｙ）から１個の水素を除いたフェノキシド型からなり、その構成成分の一つであるテトラ置換ホスホニウム（Ｘ）の置換基については何ら限定されず、置換基は互いに同一であっても異なっていてもよい。例えば、置換又は無置換のアリール基やアルキル基を置換基に有するテトラ置換ホスホニウムイオンが、熱や加水分解に対して安定であり好ましい。具体的には、テトラフェニルホスホニウム、テトラトリルホスホニウム、テトラエチルフェニルホスホニウム、テトラメトキシフェニルホスホニウム、テトラナフチルホスホニウム、テトラベンジルホスホニウム、エチルトリフェニルホスホニウム、ｎ−ブチルトリフェニルホスホニウム、２−ヒドロキシエチルトリフェニルホスホニウム、トリメチルフェニルホスホニウム、メチルジエチルフェニルホスホニウム、メチルジアリルフェニルホスホニウム、テトラ−ｎ−ブチルホスホニウム等を例示できる。
【００１３】
本発明に用いる分子会合体（Ｃ）の構成成分である、１分子内にフェノール性水酸基を２個以上有する化合物（Ｙ）としては、例えば、式（５）で表される化合物、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）メタン（通称テトラメチルビスフェノールＦ）、４，４’−スルホニルジフェノール及び式（６）で表される化合物、４，４’−イソプロピリデンジフェノール（通称ビスフェノールＡ）、ビス（４−ヒドロキシフェニル）メタン、ビス（２−ヒドロキシフェニル）メタン、（２−ヒドロキシフェニル）（４−ヒドロキシフェニル）メタン及びこれらの内ビス（４−ヒドロキシフェニル）メタン、ビス（２−ヒドロキシフェニル）メタン、（２−ヒドロキシフェニル）（４−ヒドロキシフェニル）メタンの３種の混合物（例えば、本州化学工業（株）・製、ビスフェノールＦ−Ｄ）等のビスフェノール類、１，２−ベンゼンジオール、１，３−ベンゼンジオール、１，４−ベンゼンジオール等のジヒドロキシベンゼン類、１，２，４−ベンゼントリオール等のトリヒドロキシベンゼン類、１，６−ジヒドロキシナフタレン等のジヒドロキシナフタレン類の各種異性体、２，２’−ビフェノール、４，４’−ビフェノール等のビフェノール類の各種異性体等の化合物が挙げられる。
更に、他の構成成分である共役塩基は、上記の化合物（Ｙ）から１個の水素を除いたフェノキシド型化合物である。
【化９】

【００１４】
【化１０】

（式中、Ｒ¹⁵はＣＨ₂又はＣ（ＣＨ₃）₂を表す。）
【００１５】
本発明に用いる分子会合体は、前述のようにホスホニウム−フェノキシド型の塩を構造中に有するが、従来の技術におけるホスホニウム−有機酸アニオン塩型の化合物と異なる点は、本発明の分子会合体では水素結合による高次構造がイオン結合を取り囲んでいる点である。従来の技術における塩では、イオン結合の強さのみにより反応性を制御しているのに対し、本発明の分子会合体では、常温ではアニオンの高次構造による囲い込みが活性点の保護を行う一方、成形の段階においては、この高次構造が崩れることで活性点がむき出しになり、反応性を発現する、いわゆる潜伏性が付与されている。更に高次構造が崩れ反応性が発現する際には、分子会合体に含まれる化合物（Ｙ）はフェノール性水酸基を有するため反応の架橋に取り込まれるため、従来の技術におけるホスホニウム−有機酸アニオン塩型の化合物から有機酸が遊離するのとは大きく異なり、耐湿信頼性に悪影響を与えない。
【００１６】
本発明の分子会合体の製造方法は何ら限定されないが、代表的な２方法を挙げることができる。１つ目は、テトラ置換ホスホニウム・テトラ置換ボレート（Ｚ）と、１分子内に２個以上のフェノール性水酸基を有する化合物（Ｙ）とを、高温下で反応させた後、更に沸点６０℃以上の溶媒中で熱反応させる方法である。２つ目は、１分子内に２個以上のフェノール性水酸基を有する化合物（Ｙ）と、無機塩基又は有機塩基とテトラ置換ホスホニウムハライドとを反応させる方法である。
用いるテトラ置換ホスホニウムハライドの置換基については何ら限定されることはなく、置換基は互いに同一であっても異なっていてもよい。例えば、置換又は無置換のアリール基やアルキル基を置換基に有するテトラ置換ホスホニウムイオンが、熱や加水分解に対して安定であり好ましい。具体的には、テトラフェニルホスホニウム、テトラトリルホスホニウム、テトラエチルフェニルホスホニウム、テトラメトキシフェニルホスホニウム、テトラナフチルホスホニウム、テトラベンジルホスホニウム、エチルトリフェニルホスホニウム、ｎ−ブチルトリフェニルホスホニウム、２−ヒドロキシエチルトリフェニルホスホニウム、トリメチルフェニルホスホニウム、メチルジエチルフェニルホスホニウム、メチルジアリルフェニルホスホニウム、テトラ−ｎ−ブチルホスホニウム等を例示できる。ハライドとしてはクロライドやブロマイドを例示でき、テトラ置換ホスホニウムハライドの価格や吸湿等の特性、及び入手のし易さから選択すればよく、いずれを用いても差し支えない。
【００１７】
本発明に用いる有機ホスフィン（Ｄ）は置換基全てが有機基である第３ホスフィン化合物、１つの基のみが水素である第２ホスフィン、２つの基が水素である第１ホスフィン等がある。具体的にはトリフェニルホスフィン、トリブチルホスフィン、トリシクロヘキシルホスフィン、メチルジフェニルホスフィン、ブチルジフェニルホスフィン、ジフェニルホスフィン、フェニルホスフィン、オクチルホスフィン等である。又１，２−ビス（ジフェニルホスフィノ）エタン、ビス（ジフェニルホスフィノ）メタン等でも構わない。特に入手のし易さ、価格の面ではトリフェニルホスフィンが好ましい。
本発明では分子会合体（Ｃ）と有機ホスフィン（Ｄ）を併用することに特徴があり、これについて説明する。前述のように、トリフェニルホスフィンで代表される有機ホスフィン系の硬化促進剤は、比較的低温でも硬化促進作用を示すため、これらを用いた樹脂組成物は常温時の保存性が不十分で、そのため常温で保存すると、成形時の流動性の低下から充填不良が発生したり、ＩＣチップの金ワイヤーが断線し導通不良が発生する等の問題点が生じる。又成形性向上のために、成形時の速硬化性を示すのに十分な量を添加すると、樹脂組成物の常温での保存性が極端に低下するという問題点がある。つまり単独で使用する場合には常温保存特性が悪いために取扱いが困難であった。しかし、有機ホスフィンは耐湿信頼性に優れる樹脂組成物を与えるという利点もあった。この有機ホスフィンに、特定の高次の分子構造を有し、且つ潜伏性が付与された分子会合体（Ｃ）を併用することで、有機ホスフィンの特徴を保持しつつ常温保存特性を改良しようとするのが本発明である。
【００１８】
分子会合体（Ｃ）と有機ホスフィン（Ｄ）の割合は含有するリン原子のモル比で１：０．２〜３であることが望ましい。分子会合体（Ｃ）含有のリン原子１モルに対し、有機ホスフィン含有のリン原子が０．２モルより少ない場合には有機ホスフィンの性能が十分活かされないため、望ましくない。又分子会合体（Ｃ）含有のリン原子１モルに対し、有機ホスフィン含有のリン原子が３モルより多い場合には、有機ホスフィンの欠点である常温保存特性の悪さが強調され、望ましくない。又これらの硬化促進剤の特性を損なわない範囲で、１，８−ジアザビシクロ（５，４，０）ウンデセン−７、２−メチルイミダゾール等の他の硬化促進剤と併用しても何ら問題はない。
【００１９】
本発明に用いられる無機充填材の種類については特に制限はなく、一般に封止材料に用いられているものを使用することができる。例えば、溶融破砕シリカ、溶融球状シリカ、結晶シリカ、２次凝集シリカ、アルミナ、チタンホワイト、水酸化アルミニウム等が挙げられ、特に溶融球状シリカ粉末が好ましい。形状は限りなく真球状であることが好ましく、又粒子の大きさの異なるものを混合することにより充填材量を多くすることができる。
この無機充填材の配合量としては、全エポキシ樹脂と全フェノール樹脂の合計量１００重量部あたり２００〜２４００重量部が好ましい。２００重量部未満だと、無機充填材による補強効果が充分に発現しないおそれがあり、２４００重量部を越えると、樹脂組成物の流動性が低下し成形時に充填不良等が生じるおそれがあるので好ましくない。特に、無機充填材の配合量が、全エポキシ樹脂と全フェノール樹脂の合計量１００重量部あたり２５０〜１４００重量部であれば、樹脂組成物の硬化物の吸湿率が低くなり、半田クラックの発生を防止することができ、更に溶融時の樹脂組成物の粘度が低くなるため、半導体装置内部の金線変形を引き起こすおそれがなく、より好ましい。又無機充填材は、予め充分混合しておくことが好ましい。
【００２０】
本発明のエポキシ樹脂組成物は、（Ａ）〜（Ｅ）成分の他、必要に応じてγ−グリシドキシプロピルトリメトキシシラン等のカップリング剤、カーボンブラック等の着色剤、臭素化エポキシ樹脂、酸化アンチモン、リン化合物等の難燃剤、シリコーンオイル、シリコーンゴム等の低応力成分、天然ワックス、合成ワックス、高級脂肪酸及びその金属塩類もしくはパラフィン等の離型剤、酸化防止剤等の各種添加剤を配合することができる。
本発明のエポキシ樹脂組成物は、（Ａ）〜（Ｅ）成分、及びその他の添加剤等をミキサーを用いて常温混合し、ロール、押出機等の混練機で混練し、冷却後粉砕して得られる。
本発明の樹脂組成物を用いて、半導体等の電子部品を封止し、半導体装置を製造するには、トランスファーモールド、コンプレッションモールド、インジェクションモールド等の成形方法で硬化成形すればよい。
【００２１】
【実施例】
以下に、実施例を挙げて説明するが、本発明はこれらの実施例により何ら限定されるものではない。配合割合は重量部とする。
分子会合体Ｃ１
本州化学工業（株）・製ビスフェノールＦ−Ｄ（化合物（Ｙ）に相当）３００ｇ（１．５モル）と、テトラフェニルホスホニウム・テトラフェニルボレート（Ｚ）３２９ｇ（０．５モル）とを３Ｌセパラブルフラスコに仕込み、２００℃で３時間反応させた。この反応でのベンゼン留出量は、理論生成量の９７重量％（即ちベンゼン留出率９７％）であった。この反応による粗生成物を微粉砕し、セパラブルフラスコに仕込み、２−プロパノールを粗生成物の仕込み重量の３倍量加え、内温８２．４℃（２−プロパノールの沸点温度）で１．５時間攪拌した。その後、２−プロパノールの大部分を除去し、更に加熱減圧下で低沸点分を除去した。得られた生成物を化合物Ｃ１とする。又溶媒を重メタノールとして、Ｃ１の¹Ｈ−ＮＭＲでの測定を行った。４．８ｐｐｍ付近及び３．３ｐｐｍ付近のピークは溶媒のピークで、６．４〜７．１ｐｐｍ付近のピーク群は、原料であるビスフェノールＦ［（Ｘ）１モルに対するモル数（ａ）］及びこのビスフェノールＦから１個の水素を除いたフェノキシド型の共役塩基［（Ｘ）１モルに対するモル数（ｂ）］のフェニルプロトン、７．６〜８．０ｐｐｍ付近のピーク群は、テトラフェニルホスホニウム基のフェニルプロトンと帰属され、それらの面積比から、モル比が［（ａ＋ｂ）／（Ｘ）］＝２．２／１であると計算された。化合物Ｃ１中のリン原子の量は、３．９８重量％。
【００２２】
分子会合体２
５Ｌのセパラブルフラスコに、本州化学工業（株）・製ビスフェノールＦ−Ｄ（化合物（Ｙ）に相当）３００ｇ（１．５モル）、北興化学工業（株）・製テトラフェニルホスホニウムブロマイド３１４ｇ（０．７５モル）、メタノール３０００ｇを仕込み、完全に溶解させた。そこに水酸化ナトリウムを３０ｇ含有するメタノール／水混合溶液を攪拌しながら滴下した。得られた溶液を多量の水中に滴下する再沈作業を行い、目的物を固形物として得た。濾過して固形物を取り出し、乾燥させて得られた生成物を化合物Ｃ２とした。又溶媒を重メタノールとして、Ｃ２の¹Ｈ−ＮＭＲでの測定を行った。４．８ｐｐｍ付近及び３．３ｐｐｍ付近のピークは溶媒のピークで、６．４〜７．１ｐｐｍ付近のピーク群は、原料であるビスフェノールＦ［（Ｘ）１モルに対するモル数（ａ）］及びこのビスフェノールＦから１個の水素を除いたフェノキシド型の共役塩基［（Ｘ）１モルに対するモル数（ｂ）］のフェニルプロトン、７．６〜８．０ｐｐｍ付近のピーク群は、テトラフェニルホスホニウム基のフェニルプロトンと帰属され、それらの面積比から、モル比が［（ａ＋ｂ）／（Ｘ）］＝２／１であると計算された。化合物Ｃ２中のリン原子の量は、３．４１重量％。
【００２３】
実施例１
化合物Ｃ１ ３．０重量部
トリフェニルホスフィン ０．３重量部
式（７）のビフェニル型エポキシ樹脂を主成分とする樹脂（エポキシ当量１８５、融点１０５℃） ５１重量部
【化１１】

【００２４】
式（８）のフェノールアラルキル樹脂（水酸基当量１６７、軟化点７３℃） ４９重量部
【化１２】

溶融球状シリカ（平均粒径１５μｍ） ５００重量部
カーボンブラック ２重量部
臭素化ビスフェノールＡ型エポキシ樹脂 ２重量部
カルナバワックス ２重量部
を混合し、熱ロールを用いて、９５℃で８分間混練して冷却後粉砕し、樹脂組成物を得た。得られた樹脂組成物を以下の方法で評価した。結果を表１に示す。
【００２５】
評価方法
スパイラルフロー：ＥＭＭＩ−１−６６に準じたスパイラルフロー測定用の金型を用い、金型温度１７５℃、注入圧力７０ｋｇ／ｃｍ²、硬化時間２分で測定した。スパイラルフローは流動性のパラメータであり、数値が大きい方が流動性が良好である。単位はｃｍ。
ショアＤ硬度：金型温度１７５℃、注入圧力７０ｋｇ／ｃｍ²、硬化時間２分で成形し、型開き１０秒後に測定したショアＤ硬度の値を硬化性とする。ショアＤ硬度は硬化性の指標であり、数値が大きい方が硬化性が良好である。
３０℃保存性：３０℃で６ヶ月間保存した後、スパイラルフローを測定し、調製直後のスパイラルフローに対する百分率として表す。単位は％。
耐湿信頼性：金型温度１７５℃、注入圧力７０ｋｇ／ｃｍ²、硬化時間２分で１６ｐＤＩＰを樹脂成形材料で封止した後、１７５℃、８時間で後硬化を行った。１２５℃、相対湿度１００％の水蒸気中で２０Ｖの電圧を印加した後、断線不良を調べた。１５個のパッケージの内の８個以上に不良が出るまでの時間を不良時間とした。なお測定時間は最長で５００時間とし、その時点で不良パッケージ数が８個未満であったものは、不良時間５００時間以上と示した。不良時間が長い程、耐湿信頼性に優れる。
【００２６】
実施例２〜６、比較例１〜３
表１、表２の配合に従い、実施例１と同様にして樹脂組成物を得、実施例１と同様にして評価した。結果を表１、表２に示す。
なお、実施例４に使用した結晶性エポキシ樹脂Ａは、４，４’−ビス（２，３−エポキシプロポキシ）−３，３’，５，５’−テトラメチルスチルベンを主成分とする樹脂６０重量％と４，４’−ビス（２，３−エポキシプロポキシ）−５−ターシャリブチル−２，３’，５’−トリメチルスチルベンを主成分とする樹脂４０重量％との混合物である（エポキシ当量２０９、融点１２０℃）。
実施例５に使用したオルソクレゾールノボラック型エポキシ樹脂は、エポキシ当量２００、軟化点６５℃である。
実施例５に使用したフェノールノボラック樹脂は、水酸基当量１０４、軟化点１０５℃である。
【表１】

【００２７】
【表２】

【００２８】
【発明の効果】
本発明は、常温保存特性、耐湿信頼性に優れた、挿入実装及び表面実装対応の半導体封止用エポキシ樹脂組成物、及びこれを用いて半導体素子を封止してなる半導体装置に関するものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an epoxy resin composition for semiconductor encapsulation that is excellent in storage characteristics at room temperature and moisture-reliability, and is compatible with insertion mounting and surface mounting, and a semiconductor device in which a semiconductor element is sealed using the same. .
[0002]
[Prior art]
In order to protect the bodies of diodes, transistors, IC chips and the like from mechanical and chemical effects, epoxy resin compositions for semiconductor encapsulation have been developed and produced. The items required for this resin composition are changing depending on the type of IC chip, the structure of the semiconductor device, and the environment in which it is used. However, the required items include storage at room temperature and fast curability at the time of molding. Is mentioned. In this resin composition, conventionally used curing accelerators include 2-methylimidazole, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, and the like. Accelerators have a curing acceleration effect even at relatively low temperatures, so resin compositions using these have insufficient storage stability at room temperature, so when stored at room temperature, poor filling occurs due to decreased fluidity during molding. Or the gold wire of the IC chip is disconnected, resulting in poor conduction. For this reason, the resin composition needs to be refrigerated and transported refrigerated, and the present situation is that the storage and transport are costly. One of the means for increasing the production efficiency is to shorten the molding time. For this purpose, fast curability during molding is required. The above-mentioned curing accelerators conventionally used have a problem that when a sufficient amount is added to show the fast curability at the time of molding, the storage stability of the resin composition at room temperature is extremely lowered.
[0003]
In recent years, in order to solve this problem, researches on so-called latent curing accelerators have been actively conducted that suppress the change in viscosity and fluidity at low temperatures with time and cause a curing reaction only by heating during molding. As a means for this, a proposal has been made to express latency by protecting the active site of the curing accelerator with an ion pair. JP-A-8-41290 discloses salt structures of various organic acids and phosphonium ions. A latent cure accelerator is disclosed. However, since this phosphonium salt does not have a specific high-order molecular structure and the ion pair is relatively easily affected by the external environment, in recent semiconductor encapsulation materials using low-molecular epoxy resins or phenol aralkyl resins. There is a problem that storage stability is lowered. Further, since this phosphonium salt has a salt structure with various organic acids, it is unavoidable that the organic acid is liberated during the reaction, and this has an adverse effect on moisture resistance reliability.
[0004]
[Problems to be solved by the invention]
The present invention provides an epoxy resin composition for semiconductor encapsulation that is excellent in normal temperature storage characteristics and moisture resistance reliability, and is compatible with insertion mounting and surface mounting, and a semiconductor device formed by sealing a semiconductor element using the same. It is.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to improve room temperature storage characteristics and moisture resistance reliability, the present inventor found that an epoxy resin composition used as a curing accelerator in combination with a specific compound exhibits extremely excellent characteristics. The present invention has been completed based on the findings.
That is, the present invention relates to (A) epoxy resin, (B) phenol resin, (C) tetra-substituted phosphonium (X), compound (Y) having two or more phenolic hydroxyl groups in one molecule, and phenolic in one molecule. A molecular association with a conjugate base of a compound (Y) having two or more hydroxyl groups, wherein the conjugate base removes one hydrogen from the compound (Y) having two or more phenolic hydroxyl groups in one molecule. A molecular compound comprising a phenoxide-type compound, (D) an organic phosphine, and (E) an inorganic filler as essential components, and an equivalent ratio of epoxy groups of all epoxy resins to phenolic hydroxyl groups of all phenol resins is 0.5-2. And the amount of the inorganic filler (E) is 200 to 2400 parts by weight per 100 parts by weight of the total amount of all the epoxy resins and all the phenol resins. It is a formed product.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The epoxy resin used in the present invention refers to monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule. For example, biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, orthocresol novolak type epoxy resin, phenol novolac type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, triazine nucleus-containing epoxy Examples thereof include resins and dicyclopentadiene-modified phenol type epoxy resins, and these may be used alone or in combination.
Among these epoxy resins, crystalline epoxy resins having a melting point of 50 to 150 ° C. are preferable. Such a crystalline epoxy resin has a rigid structure such as a biphenyl skeleton, a bisphenol skeleton, and a stilbene skeleton in the main chain, and exhibits a crystallinity because of its relatively low molecular weight. A crystalline epoxy resin is a solid crystallized at room temperature, but rapidly melts into a low-viscosity liquid in a temperature range above the melting point. The melting point of the crystalline epoxy resin indicates the temperature at the top of the endothermic peak of crystal melting, which is heated from room temperature at a heating rate of 5 ° C./min using a differential scanning calorimeter. As the crystalline epoxy resin satisfying these conditions, in particular, one or more selected from the general formula (1) and the general formula (2), or the stilbene type epoxy resin represented by the general formula (3) and the general formula (4 The mixture with the stilbene type epoxy resin shown by this is preferable.
[Chemical formula 5]

(Wherein R ¹ Is a group or atom selected from a hydrogen atom, a linear or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, or a halogen, which may be the same or different. )
[0007]
[Chemical 6]

(Wherein R ² Is a group or atom selected from a hydrogen atom, a linear or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, or a halogen, which may be the same or different. )
[0008]
[Chemical 7]

(Where R3 to R ^Ten Each independently represents a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, or a group or atom selected from halogen. However, the two aryl groups bonded to the carbon-carbon double bond are different from each other. )
[0009]
[Chemical 8]

(Wherein R ¹¹ ~ R ¹⁴ Each independently represents a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, or a group or atom selected from halogen. However, the two aryl groups bonded to the carbon-carbon double bond are the same as each other.
)
Substituent R of biphenyl type epoxy resin represented by general formula (1) ¹ And a substituent R of the bisphenol type epoxy resin represented by the general formula (2) ² Are groups or atoms selected from a hydrogen atom, a linear or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, or a halogen, which may be the same or different from each other, for example, methyl Group, ethyl group, propyl group, butyl group, cyclohexyl group, phenyl group, chlorine atom, bromine atom and the like, and methyl group is particularly preferable.
Substituent R of stilbene type epoxy resin represented by general formula (3) and general formula (4) ^Three ~ R ¹⁴ Is a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, or a group or atom selected from halogen, which may be the same as or different from each other. For example, a hydrogen atom, methyl Group, ethyl group, propyl group, butyl group, amyl group, hexyl group (including isomers), cyclohexyl group, chlorine atom, bromine atom, etc., especially from the low melt viscosity of epoxy resin, methyl A group, an ethyl group, a propyl group, or a butyl group is preferred.
[0010]
In mixing the stilbene type epoxy resin of the general formula (3) and the stilbene type epoxy resin of the general formula (4), the melting point may be lowered by mixing both compounds, and the mixing method is not particularly limited. For example, there are methods such as mixing stilbene type phenols, which are raw materials of stilbene type epoxy resins, before glycidyl etherification, or melting and mixing both stilbene type epoxy resins, but in each case the melting point is It adjusts so that it may become 50-150 degreeC. Both the stilbene type epoxy resin of the general formula (3) and the stilbene type epoxy resin of the general formula (4) have various structures depending on the types of substituents. The above may be mixed.
As the stilbene type epoxy resin of the general formula (3), 5-tertiarybutyl-4,4′-dihydroxy-2,3 ′, 5′-trimethylstilbene is available from the viewpoint of availability, performance and raw material price. 3-tertiarybutyl-4,4′-dihydroxy-3 ′, 5,5′-trimethylstilbene glycidyl etherified product is particularly preferred.
As the stilbene type epoxy resin of the general formula (4), 4,4′-dihydroxy-3,3 ′, 5,5′-tetramethylstilbene, 4,4′-dihydroxy-3 is used from the viewpoint of performance and raw material price. Particularly preferred are glycidyl etherified products of 3,3′-ditertiarybutyl-6,6′-dimethylstilbene and 4,4′-dihydroxy-3,3′-ditertiarybutyl-5,5′-dimethylstilbene.
[0011]
The phenol resin used in the present invention refers to monomers, oligomers, and polymers in general having two or more phenolic hydroxyl groups in one molecule. For example, a phenol novolak resin, a cresol novolak resin, a phenol aralkyl resin, a naphthol aralkyl resin, a terpene-modified phenol resin, a dicyclopentadiene-modified phenol resin, and the like may be used alone or in combination. These phenol resins can be used without limitation in terms of molecular weight, softening point, hydroxyl equivalent, and the like.
Among these phenolic resins, the number of hydroxyl groups in the molecule is small, so the water absorption of the molded product is small, the molecule has an appropriate flexibility, the reactivity in the curing reaction is good, and the viscosity can be lowered. Therefore, a phenol aralkyl resin containing phenylene or diphenylene in the skeleton is particularly preferable.
The equivalent ratio of epoxy groups of all epoxy resins used in the present invention to phenolic hydroxyl groups of all phenol resins is preferably 0.5 to 2, particularly preferably 0.7 to 1.5. If it is out of the range of 0.5 to 2, curability, moisture resistance and the like are lowered, which is not preferable.
[0012]
The molecular compound (C) used in the present invention includes a tetra-substituted phosphonium (X), a compound (Y) having two or more phenolic hydroxyl groups in one molecule, and a compound (Y) having two or more phenolic hydroxyl groups in one molecule. ) In the form of a phenoxide type compound in which one hydrogen is removed from the compound (Y) having two or more phenolic hydroxyl groups in one molecule. The substituent of tetra-substituted phosphonium (X) which is one of the above is not limited at all, and the substituents may be the same or different from each other. For example, a tetra-substituted phosphonium ion having a substituted or unsubstituted aryl group or alkyl group as a substituent is preferable because it is stable against heat and hydrolysis. Specifically, tetraphenylphosphonium, tetratolylphosphonium, tetraethylphenylphosphonium, tetramethoxyphenylphosphonium, tetranaphthylphosphonium, tetrabenzylphosphonium, ethyltriphenylphosphonium, n-butyltriphenylphosphonium, 2-hydroxyethyltriphenylphosphonium, Examples include trimethylphenylphosphonium, methyldiethylphenylphosphonium, methyldiallylphenylphosphonium, and tetra-n-butylphosphonium.
[0013]
Examples of the compound (Y) having two or more phenolic hydroxyl groups in one molecule, which is a constituent of the molecular aggregate (C) used in the present invention, include, for example, a compound represented by the formula (5), bis (4 -Hydroxy-3,5-dimethylphenyl) methane (commonly known as tetramethylbisphenol F), 4,4'-sulfonyldiphenol and a compound represented by formula (6), 4,4'-isopropylidenediphenol (commonly referred to as bisphenol) A), bis (4-hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane and bis (4-hydroxyphenyl) methane, bis (2 -Hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, a mixture of three kinds (for example, Bisphenols such as bisphenol FD manufactured by Honshu Chemical Industry Co., Ltd., dihydroxybenzenes such as 1,2-benzenediol, 1,3-benzenediol, 1,4-benzenediol, 1,2, Trihydroxybenzenes such as 4-benzenetriol, various isomers of dihydroxynaphthalene such as 1,6-dihydroxynaphthalene, various isomers of biphenols such as 2,2′-biphenol and 4,4′-biphenol, etc. Compounds.
Furthermore, the conjugate base which is another constituent component is a phenoxide type compound obtained by removing one hydrogen from the above compound (Y).
[Chemical 9]

[0014]
Embedded image

(Wherein R ¹⁵ Is CH ₂ Or C (CH _Three ) ₂ Represents. )
[0015]
The molecular aggregate used in the present invention has a phosphonium-phenoxide type salt in the structure as described above. However, the molecular aggregate of the present invention is different from the phosphonium-organic acid anion salt type compound in the prior art. Then, the higher-order structure by a hydrogen bond surrounds the ionic bond. In the salt in the conventional technique, the reactivity is controlled only by the strength of the ionic bond, whereas in the molecular aggregate of the present invention, the enclosure by the higher-order structure of the anion protects the active site at room temperature. In the molding stage, the higher-order structure is broken, so that the active sites are exposed, and so-called latency that expresses reactivity is imparted. Further, when the higher order structure collapses and the reactivity is expressed, the compound (Y) contained in the molecular aggregate has a phenolic hydroxyl group and is therefore incorporated into the crosslinking of the reaction. Therefore, the phosphonium-organic acid anion salt in the conventional technique Unlike the release of organic acid from a compound of the type, it does not adversely affect moisture resistance reliability.
[0016]
Although the manufacturing method of the molecular association body of this invention is not limited at all, Two typical methods can be mentioned. First, after reacting tetra-substituted phosphonium / tetra-substituted borate (Z) with a compound (Y) having two or more phenolic hydroxyl groups in one molecule at a high temperature, the boiling point is 60 ° C. or higher. It is the method of making it heat-react in the solvent of. The second is a method of reacting a compound (Y) having two or more phenolic hydroxyl groups in one molecule, an inorganic base or an organic base and a tetra-substituted phosphonium halide.
The substituent of the tetra-substituted phosphonium halide used is not limited at all, and the substituents may be the same or different from each other. For example, a tetra-substituted phosphonium ion having a substituted or unsubstituted aryl group or alkyl group as a substituent is preferable because it is stable against heat and hydrolysis. Specifically, tetraphenylphosphonium, tetratolylphosphonium, tetraethylphenylphosphonium, tetramethoxyphenylphosphonium, tetranaphthylphosphonium, tetrabenzylphosphonium, ethyltriphenylphosphonium, n-butyltriphenylphosphonium, 2-hydroxyethyltriphenylphosphonium, Examples include trimethylphenylphosphonium, methyldiethylphenylphosphonium, methyldiallylphenylphosphonium, and tetra-n-butylphosphonium. Chlorides and bromides can be exemplified as halides, which may be selected from the price, moisture absorption and other characteristics of the tetra-substituted phosphonium halide, and availability, and any of them may be used.
[0017]
The organic phosphine (D) used in the present invention includes a third phosphine compound in which all substituents are organic groups, a second phosphine in which only one group is hydrogen, a first phosphine in which two groups are hydrogen, and the like. Specific examples include triphenylphosphine, tributylphosphine, tricyclohexylphosphine, methyldiphenylphosphine, butyldiphenylphosphine, diphenylphosphine, phenylphosphine, and octylphosphine. Further, 1,2-bis (diphenylphosphino) ethane, bis (diphenylphosphino) methane, or the like may be used. In particular, triphenylphosphine is preferable in terms of availability and price.
The present invention is characterized by the combined use of the molecular aggregate (C) and the organic phosphine (D), which will be described. As described above, organic phosphine-based curing accelerators typified by triphenylphosphine exhibit a curing accelerating action even at relatively low temperatures, and thus resin compositions using these have insufficient storage stability at room temperature, For this reason, when stored at room temperature, problems such as poor filling due to a decrease in fluidity during molding, and poor conduction due to breakage of the gold wire of the IC chip occur. In addition, if a sufficient amount is added for improving the moldability to show the fast curability at the time of molding, there is a problem that the storage stability of the resin composition at room temperature is extremely lowered. In other words, when used alone, it is difficult to handle due to poor room temperature storage characteristics. However, organic phosphine also has an advantage of providing a resin composition having excellent moisture resistance reliability. By using this organic phosphine together with a molecular aggregate (C) having a specific higher-order molecular structure and having a latent property, it is intended to improve the room temperature storage characteristics while retaining the characteristics of the organic phosphine. This is what the present invention does.
[0018]
The ratio of the molecular aggregate (C) to the organic phosphine (D) is preferably 1: 0.2 to 3 in terms of the molar ratio of phosphorus atoms contained. When the number of organic phosphine-containing phosphorus atoms is less than 0.2 mol with respect to 1 mol of phosphorus atoms contained in the molecular aggregate (C), the performance of the organic phosphine is not fully utilized, which is not desirable. Further, when there are more than 3 moles of organic phosphine-containing phosphorus atoms per 1 mole of phosphorus atoms contained in the molecular aggregate (C), the disadvantage of organic phosphine, which is a disadvantage of room temperature storage characteristics, is emphasized. In addition, there is no problem even if it is used in combination with other curing accelerators such as 1,8-diazabicyclo (5,4,0) undecene-7, 2-methylimidazole as long as the properties of these curing accelerators are not impaired. .
[0019]
There is no restriction | limiting in particular about the kind of inorganic filler used for this invention, What is generally used for the sealing material can be used. Examples thereof include fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica, alumina, titanium white, aluminum hydroxide, and the like, and fused spherical silica powder is particularly preferable. The shape is preferably infinitely spherical, and the amount of filler can be increased by mixing particles having different particle sizes.
As a compounding quantity of this inorganic filler, 200-2400 weight part is preferable per 100 weight part of total amounts of all the epoxy resins and all the phenol resins. If the amount is less than 200 parts by weight, the reinforcing effect of the inorganic filler may not be sufficiently exhibited. If the amount exceeds 2400 parts by weight, the fluidity of the resin composition may be reduced, and there is a risk of poor filling during molding. Absent. In particular, if the blending amount of the inorganic filler is 250 to 1400 parts by weight per 100 parts by weight of the total amount of all epoxy resins and all phenolic resins, the moisture absorption rate of the cured product of the resin composition becomes low, and solder cracks are generated. Further, since the viscosity of the resin composition at the time of melting is lowered, there is no possibility of causing gold wire deformation inside the semiconductor device, which is more preferable. The inorganic filler is preferably mixed well in advance.
[0020]
The epoxy resin composition of the present invention includes components (A) to (E), a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a colorant such as carbon black, and a brominated epoxy resin as necessary. , Flame retardants such as antimony oxide and phosphorus compounds, low stress components such as silicone oil and silicone rubber, natural waxes, synthetic waxes, mold release agents such as higher fatty acids and their metal salts or paraffin, and various additives such as antioxidants Can be blended.
In the epoxy resin composition of the present invention, the components (A) to (E) and other additives are mixed at room temperature using a mixer, kneaded with a kneader such as a roll or an extruder, pulverized after cooling. can get.
In order to seal an electronic component such as a semiconductor and manufacture a semiconductor device using the resin composition of the present invention, it may be cured by a molding method such as a transfer mold, a compression mold, or an injection mold.
[0021]
【Example】
Examples are described below, but the present invention is not limited to these examples. The blending ratio is parts by weight.
Molecular aggregate C1
300 g (1.5 mol) of bisphenol FD (corresponding to compound (Y)) manufactured by Honshu Chemical Industry Co., Ltd. and 329 g (0.5 mol) of tetraphenylphosphonium tetraphenylborate (Z) The flask was charged and reacted at 200 ° C. for 3 hours. The amount of benzene distilled in this reaction was 97% by weight of the theoretical amount produced (that is, 97% benzene distillation rate). The crude product resulting from this reaction is finely pulverized, charged into a separable flask, 2-propanol is added in an amount three times the charged weight of the crude product, and the internal temperature is 82.4 ° C. (boiling point temperature of 2-propanol). Stir for 5 hours. Thereafter, most of 2-propanol was removed, and the low boiling point content was further removed under heating and reduced pressure. The obtained product is designated as Compound C1. The solvent is deuterated methanol and C1 ¹ Measurement by H-NMR was performed. The peaks around 4.8 ppm and 3.3 ppm are solvent peaks, and the peaks around 6.4 to 7.1 ppm are the number of moles of bisphenol F [(X) per mole of (X) (a)]. The phenoxide-type conjugate base obtained by removing one hydrogen from bisphenol F [(X), the number of moles per mole (b)] of the phenyl proton, and the peak group near 7.6 to 8.0 ppm is the tetraphenylphosphonium group. Assigned to phenyl protons, and from their area ratio, the molar ratio was calculated to be [(a + b) / (X)] = 2.2 / 1. The amount of phosphorus atom in the compound C1 is 3.98% by weight.
[0022]
Molecular aggregate 2
Into a 5 L separable flask, 300 g (1.5 mol) of bisphenol FD (corresponding to compound (Y)) manufactured by Honshu Chemical Industry Co., Ltd., 314 g of tetraphenylphosphonium bromide manufactured by Hokuko Chemical Industry Co., Ltd. (0) .75 mol) and 3000 g of methanol were charged and completely dissolved. A methanol / water mixed solution containing 30 g of sodium hydroxide was added dropwise thereto while stirring. The reprecipitation operation in which the obtained solution was dropped into a large amount of water was performed to obtain the target product as a solid. The product obtained by filtering to remove the solid and drying was designated as compound C2. The solvent is deuterated methanol and C2. ¹ Measurement by H-NMR was performed. The peaks around 4.8 ppm and 3.3 ppm are solvent peaks, and the peaks around 6.4 to 7.1 ppm are the number of moles of bisphenol F [(X) per mole of (X) (a)]. The phenoxide-type conjugate base obtained by removing one hydrogen from bisphenol F [(X), the number of moles per mole (b)] of the phenyl proton, and the peak group near 7.6 to 8.0 ppm is the tetraphenylphosphonium group. Assigned to phenyl protons, and from their area ratio, the molar ratio was calculated to be [(a + b) / (X)] = 2/1. The amount of phosphorus atom in Compound C2 is 3.41% by weight.
[0023]
Example 1
Compound C1 3.0 parts by weight
0.3 parts by weight of triphenylphosphine
51 parts by weight of resin mainly composed of biphenyl type epoxy resin of formula (7) (epoxy equivalent 185, melting point 105 ° C.)
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[0024]
49 parts by weight of phenol aralkyl resin of formula (8) (hydroxyl equivalent: 167, softening point: 73 ° C.)
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500 parts by weight of fused spherical silica (average particle size 15 μm)
2 parts by weight of carbon black
Brominated bisphenol A type epoxy resin 2 parts by weight
Carnauba wax 2 parts by weight
Were mixed using a hot roll at 95 ° C. for 8 minutes, cooled and pulverized to obtain a resin composition. The obtained resin composition was evaluated by the following methods. The results are shown in Table 1.
[0025]
Evaluation methods
Spiral flow: using a mold for spiral flow measurement according to EMMI-1-66, mold temperature 175 ° C., injection pressure 70 kg / cm ² Measured at a curing time of 2 minutes. Spiral flow is a fluidity parameter, and a larger value means better fluidity. The unit is cm.
Shore D hardness: mold temperature 175 ° C., injection pressure 70 kg / cm ² The mold was cured in a curing time of 2 minutes, and the Shore D hardness value measured 10 seconds after mold opening was defined as curability. Shore D hardness is an index of curability, and the larger the value, the better the curability.
Storage at 30 ° C .: After storing at 30 ° C. for 6 months, the spiral flow was measured and expressed as a percentage of the spiral flow immediately after preparation. Units%.
Moisture resistance reliability: mold temperature 175 ° C., injection pressure 70 kg / cm ² After 16pDIP was sealed with a resin molding material with a curing time of 2 minutes, post-curing was performed at 175 ° C. for 8 hours. After applying a voltage of 20 V in water vapor at 125 ° C. and 100% relative humidity, the disconnection failure was examined. The time until a defect appears in 8 or more of the 15 packages was defined as a defect time. The measurement time was 500 hours at the longest, and when the number of defective packages was less than 8 at that time, the defective time was indicated as 500 hours or more. The longer the defect time, the better the moisture resistance reliability.
[0026]
Examples 2-6, Comparative Examples 1-3
According to the formulations in Tables 1 and 2, resin compositions were obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.
The crystalline epoxy resin A used in Example 4 is a resin 60 mainly composed of 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylstilbene. It is a mixture of 40% by weight of a resin mainly composed of 4,4′-bis (2,3-epoxypropoxy) -5-tertiarybutyl-2,3 ′, 5′-trimethylstilbene (epoxy) Equivalent 209, melting point 120 ° C.).
The ortho-cresol novolak type epoxy resin used in Example 5 has an epoxy equivalent of 200 and a softening point of 65 ° C.
The phenol novolac resin used in Example 5 has a hydroxyl group equivalent of 104 and a softening point of 105 ° C.
[Table 1]

[0027]
[Table 2]

[0028]
【The invention's effect】
The present invention relates to an epoxy resin composition for semiconductor encapsulation that is excellent in storage characteristics at room temperature and moisture-reliability, and is compatible with insertion mounting and surface mounting, and a semiconductor device in which a semiconductor element is sealed using the same. .

Claims (9)

(A) epoxy resin, (B) phenol resin, (C) tetra-substituted phosphonium (X), compound (Y) having two or more phenolic hydroxyl groups in one molecule, and two or more phenolic hydroxyl groups in one molecule From a phenoxide-type compound obtained by removing one hydrogen from a compound (Y) having two or more phenolic hydroxyl groups in one molecule, wherein the conjugate base of the compound (Y) has a conjugate base. The molecular compound, (D) organic phosphine, and (E) inorganic filler are essential components, and the equivalent ratio of epoxy groups of all epoxy resins to phenolic hydroxyl groups of all phenol resins is 0.5 to 2, The epoxy resin composition is characterized in that the blending amount of the material (E) is 200 to 2400 parts by weight per 100 parts by weight of the total amount of all epoxy resins and all phenol resins. , The ratio of the molecular association (C) an organic phosphine (D) is 1 in a molar ratio of phosphorus atoms contained: epoxy resin composition is 0.2 to 3. The epoxy resin composition according to claim 1, wherein the organic phosphine (D) is triphenylphosphine. A conjugate base of compound (Y) having two or more phenolic hydroxyl groups in one molecule is selected from among dihydroxybenzenes, trihydroxybenzenes, bisphenols, biphenols, dihydroxynaphthalene, phenol novolac resins, and phenol aralkyl resins. The epoxy resin composition according to claim 1, wherein the epoxy resin composition is one or more selected. The epoxy resin composition according to any one of claims 1 to 3 , wherein the tetra-substituted phosphonium (X) is tetraphenylphosphonium. The epoxy resin composition according to any one of claims 1 to 4 , wherein the epoxy resin (A) is a crystalline epoxy resin having a melting point of 50 to 150 ° C. The epoxy resin composition according to claim 5 , wherein the crystalline epoxy resin having a melting point of 50 to 150 ° C is at least one selected from the general formula (1) and the general formula (2).

(In the formula, R ¹ is a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, or a group or atom selected from halogens, which may be the same or different from each other. Good.)

(In the formula, R ² is a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, or a group or atom selected from halogens, which may be the same or different from each other. Good.) 6. The epoxy resin composition according to claim 5 , wherein the crystalline epoxy resin having a melting point of 50 to 150 ° C. is a mixture of a stilbene type epoxy resin represented by the general formula (3) and a stilbene type epoxy resin represented by the general formula (4). object.

(In the formula, R ^{3 to} R ¹⁰ each independently represents a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, or a group or atom selected from halogen. However, carbon-carbon The two aryl groups bonded to the double bond are different from each other.)

(Wherein R ^{11 to} R ¹⁴ each independently represents a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, or a group or atom selected from halogen. However, carbon-carbon The two aryl groups bonded to the double bond are the same as each other.) The epoxy resin composition according to any one of claims 1 to 7 , wherein the phenol resin (B) is a phenol aralkyl resin. Wherein a obtained by encapsulating a semiconductor element using any of the epoxy resin composition according to claim 1-8, wherein.