JP3611002B2 - Epoxy resin composition, method for producing the same, and semiconductor device - Google Patents

Description

（但し、式中Ｒは水素原子、ハロゲン原子又は炭素数１〜５のアルキル基であり、ｑは０〜５の整数である。）
で示されるエポキシ樹脂をエポキシ樹脂全体の２０重量％以上含むものを使用すると共に、硬化剤としてフェノールノボラック樹脂、レゾール型フェノール樹脂、トリフェノールアルカン型樹脂、多官能型フェノール樹脂、ジシクロペンタジエン型フェノール樹脂、ナフタレン環含有フェノール樹脂、フェノールアラルキル樹脂から選ばれるフェノール樹脂を使用し、無機質充填剤として、９７重量％以上が粒径２５μｍ以下で、かつ平均粒径が２．５μｍ未満であり、予めエポキシ樹脂及び／又は硬化剤のみと均一溶融混合処理した微細溶融シリカを全無機質充填剤中に１〜５０重量％含み、しかも平均粒径が３〜１５μｍの球状溶融シリカを含有する無機質充填剤を使用することを特徴とするエポキシ樹脂組成物を提供する。
また、本発明は、エポキシ樹脂、硬化剤、硬化触媒及び無機質充填剤を含有するエポキシ樹脂組成物を製造する方法において、エポキシ樹脂として下記一般式（１）
【化７】

（但し、式中Ｒは水素原子、ハロゲン原子又は炭素数１〜５のアルキル基であり、ｑは０〜５の整数である。）
で示されるエポキシ樹脂をエポキシ樹脂全体の２０重量％以上含むものを使用すると共に、硬化剤としてフェノールノボラック樹脂、レゾール型フェノール樹脂、トリフェノールアルカン型樹脂、多官能型フェノール樹脂、ジシクロペンタジエン型フェノール樹脂、ナフタレン環含有フェノール樹脂、フェノールアラルキル樹脂から選ばれるフェノール樹脂を使用し、無機質充填剤として、９７重量％以上が粒径２５μｍ以下で、かつ平均粒径が２．５μｍ未満である微細溶融シリカを全無機質充填剤中に１〜５０重量％含み、しかも平均粒径が３〜１５μｍの球状溶融シリカを含有する無機質充填剤を使用し、上記微細溶融シリカをエポキシ樹脂及び／又は硬化剤のみと予め均一溶融混合処理し、これを残りの成分と混合することを特徴とするエポキシ樹脂組成物の製造方法を提供する。
更に、本発明は、エポキシ樹脂組成物の硬化物で封止された半導体装置を提供する。
【００１０】
以下、本発明につき更に詳細に説明すると、本発明のエポキシ樹脂組成物は、エポキシ樹脂、硬化剤及び無機質充填剤を必須成分として含有してなるものである。
【００１１】
ここで、エポキシ樹脂としては、その分子中にエポキシ基を少なくとも２個有する化合物である限り、分子構造、分子量等は特に限定されず、具体的にはフェノールノボラック型エポキシ樹脂、ビフェニル型エポキシ樹脂、ビスフェノール型エポキシ樹脂、アラルキル型エポキシ樹脂、多官能型エポキシ樹脂、ジシクロペンタジエン含有エポキシ樹脂、ナフタレン環含有エポキシ樹脂、複素環型エポキシ樹脂、これらにハロゲン原子を導入したエポキシ樹脂等を例示することができる。
【００１２】
本発明では、エポキシ樹脂として特に下記一般式（１）で示されるビフェニル型エポキシ樹脂を使用することが望ましい。
【００１３】
【化２】

（但し、式中Ｒは水素原子、ハロゲン原子又は炭素数１〜５のアルキル基であり、ｑは０〜５の整数である。）
【００１４】
上記式（１）において、Ｒとしては、水素原子、臭素原子、塩素原子、フッ素原子等のハロゲン原子、メチル基、エチル基、プロピル基、ブチル基、ペンチル基等の炭素数１〜５のアルキル基が挙げられる。
【００１５】
式（１）のビフェニル型エポキシ樹脂の配合量は、組成物中に配合するエポキシ樹脂全体の２０重量％以上、特に５０重量％以上の範囲とすることが好ましい。式（１）のビフェニル型エポキシ樹脂の配合量が２０重量％に満たないと、低吸湿化が得られない場合があり、吸湿後の熱衝撃時の耐クラック性が十分改善されない上、高流動性が得られないため、成形性、硬化特性等に劣る場合がある。
【００１６】
次に、硬化剤としては、１分中にエポキシ基と反応する官能基を２個以上有する化合物である限り、分子構造、分子量は特に限定されず、フェノールノボラック樹脂、レゾール型フェノール樹脂、トリフェノールアルカン型樹脂、多官能型フェノール樹脂、ジシクロペンタジエン型フェノール樹脂、ナフタレン環含有フェノール樹脂、フェノールアラルキル樹脂等が挙げられるが、これらの中でもナフタレン環含有フェノール樹脂、フェノールアラルキル樹脂が好適に使用される。
【００１７】
ナフタレン環含有フェノール樹脂、フェノールアラルキル樹脂としては、それぞれ下記化合物を挙げることができる。
【００１８】
【化３】

（但し、Ｒ^１は水素原子、塩素、臭素等のハロゲン原子又は炭素数１〜５のアルキル基を示し、ｍは０〜３の整数、ｋ及びｇは０又は１以上の整数、ｐは１以上の整数である。）
【００１９】
【化４】

【００２０】
ここで、ナフタレン環含有フェノール樹脂、フェノールアラルキル樹脂の配合量は、フェノール樹脂全体の１０〜１００％（重量％、以下同様）、好ましくは１０〜９０％、特に２０〜７０％の使用が好ましく、配合量が１０％に満たないと低吸湿性が得られない場合がある。
【００２１】
本発明において、硬化剤の配合量は常用量であるが、硬化剤としてフェノール樹脂を使用した場合、全エポキシ樹脂中のエポキシ基の量（ａ）とフェノール性水酸基の量（ｂ）とのモル比を（ａ）／（ｂ）＝０．５〜１．５、特に０．８〜１．２の範囲とする配合が好ましく、配合比が上記範囲外になると硬化性、耐クラック性、吸湿性に劣る場合がある。
【００２２】
本発明では、硬化触媒を配合することができる。硬化触媒としては、エポキシ樹脂と硬化剤の反応を促進するものであれば分子量、分子構造は特に限定されず、例えばイミダゾール化合物、アミン系硬化促進剤、リン系化合物等が挙げられるが、耐湿信頼性の高いエポキシ樹脂組成物を得るためにはリン系化合物を用いることが望ましい。また、硬化触媒の配合量は特に制限はないが、エポキシ樹脂及び硬化剤の合計量１００部（重量部、以下同様）に対して０．２〜５部、特に０．４〜３部とすることが好ましい。
【００２３】
本発明で使用される無機質充填剤としては、９７％以上が粒径２５μｍ以下で、かつ平均粒径が２．５μｍ未満であり、予めエポキシ樹脂及び／又は硬化剤と均一混合処理した微細溶融シリカを全無機質充填剤中に少なくとも１％以上含むものを使用する。
【００２４】
ここで、微細溶融シリカとしては、９７％以上、好ましくは９８〜１００％が粒径２５μｍ以下であり、平均粒径（例えばＸ線回折法による重量平均として）が２．５μｍ未満、好ましくは０．１〜２．４μｍ、より好ましくは０．５〜２．２μｍ程度であるものを使用する。この範囲外であると、流動性が低下したり、バリ発生を抑えることができない。
【００２５】
本発明において上記微細溶融シリカは、予めエポキシ樹脂及び／又は硬化剤と均一混合処理する。この場合、均一混合処理は、ミキサー等によって十分混合した後、熱ロール、ニーダー、エクストルーダー等により１００〜１２０℃で溶融混合処理を行うのが好適である。
【００２６】
また、上記処理した微細溶融シリカは、全無機質充填剤中に少なくとも１％以上、通常１〜５０％、好ましくは３〜２５％、より好ましくは５〜１５％含むことが必要であり、前処理した微細溶融シリカの含有量が１％に満たないと流動性が低下したり、バリ発生を抑えることができない。
【００２７】
更に、上記微細溶融シリカの配合量は、組成物全体の１〜１５％、特に２〜７％の範囲とすることが、流動性、バリ発生の点から好適である。
【００２８】
なお、通常、微細溶融シリカは、比表面積が大きく、比重の小さいことから、単純配合では他成分との均一分散性、特にエポキシ樹脂やフェノール樹脂といったレジン成分との均一分散が困難であり、このため微細溶融シリカを単純配合すると、十分な流動性、バリ発生の抑制、耐半田リフロー性が得られない場合があったが、このような処理を行った微細溶融シリカを上記範囲で含有する無機質充填剤を使用すると、これら問題点が解決され、流動性が良好で、成形性、耐半田リフロー性に優れた硬化物を与えるエポキシ樹脂組成物を得ることができるものである。
【００２９】
本発明において、上記微細溶融シリカ以外の無機質充填剤としては、通常エポキシ樹脂組成物に配合されるものを使用することができる。具体的には、結晶性シリカ、溶融シリカ、窒化アルミニウム、窒化珪素、炭化珪素、アルミナ、ボロンナイトライド、酸化チタン、ガラス繊維等が挙げられ、中でも溶融シリカが好適である。
【００３０】
これら無機質充填剤の平均粒径や形状は特に限定されないが、平均粒径が３〜１５μｍであるものが好ましく、また高充填化やチップ表面に対する応力を小さくするため球状のものが好ましく使用される。なお、無機質充填剤は樹脂とその表面の結合強度を強くするため、シランカップリング剤、チタネートカップリング剤等のカップリング剤で予め表面処理したものを使用することが低吸水性、耐熱衝撃性及び耐クラック性を向上させる点で好ましい。
【００３１】
上記した微細溶融シリカを含めた無機質充填剤の合計配合量は特に制限されないが、エポキシ樹脂及び硬化剤の合計量１００部に対して１００〜１３００部、特に２００〜９００部の範囲とすることが好ましい。
【００３２】
本発明の組成物には、本発明の目的に反しない限度において、更に必要に応じてその他の各種添加剤を配合することができる。添加剤は用途に応じて適宜選択されるが、例えば熱可塑性樹脂、熱可塑性エラストマー、有機合成ゴム、シリコーン系の金属塩等の低応力剤、カルナバワックス等のワックス類、ステアリン酸等の脂肪酸やそのエステル、金属塩等の離型剤、カーボンブラック、コバルトブルー、ベンガラ等の顔料、酸化アンチモン、ハロゲン化合物等の難燃化剤、グリシドキシプロピルトリメトキシシラン等のシランカップリング剤、アルキルチタネート類等の表面処理剤、老化防止剤、その他の添加剤の１種又は２種以上を配合することができる。
【００３３】
本発明のエポキシ樹脂組成物を成形材料として調製する場合の一般的な方法としては、上記の必須成分とその他の添加剤を所定の組成比で配合し、これをミキサー等によって十分混合した後、熱ロール、ニーダー、エクストルーダー等による溶融混合処理を行い、次いで冷却固化させ、適当な大きさに粉砕して成形材料とすることができる。このようにして得られた成形材料は、半導体装置をはじめとする電子部品又は電気部品の封止、被覆に用いることにより、高温高湿下での優れた信頼性を付与させることができる。
【００３４】
本発明の半導体装置は、上記の封止用樹脂組成物を用いて半導体素子を封止することにより容易に製造することができる。ここで、封止を行う半導体素子としては、例えば集積回路、演算回路、トランジスタ、サイリスタ、ダイオード等が挙げられるが、特に限定されるものではない。封止の最も一般的な方法としては、トランスファー成形法が挙げられる。この場合、エポキシ樹脂組成物の成形温度は１５０〜１８０℃で３０〜１８０秒間、ポストキュアーは１５０〜１８０℃で２〜１６時間行うことが望ましい。
【００３５】
また、上記エポキシ樹脂組成物は、成形の後に更に加熱して後硬化させることが好ましい。ここで、後硬化は１５０℃以上の加熱条件で行うことが望ましい。
【００３６】
【発明の効果】
本発明のエポキシ樹脂組成物は、流動性、バリ発生抑制といった成形性が良好であると共に、低吸湿性で耐リフロー性に優れた硬化物を与え、このエポキシ樹脂組成物の硬化物でＩＣ、ＬＳＩ、トランジスタ等のパッケージを封止すると、成形性に優れた信頼性の高い半導体製品を生産性良く製造することができる。
【００３７】
【実施例】
以下、実施例及び比較例を示して本発明を具体的に説明するが、本発明は下記実施例に制限されるものではない。なお、各例中の部はいずれも重量部である。
【００３８】
〔実施例１〜６、比較例１〜３〕
表１に示すエポキシ樹脂、フェノール樹脂及び下記に示す微細溶融シリカを表２に示す割合で使用し、更に下記方法で予備混合（１）又は（２）を行い、また硬化触媒としてトリフェニルホスフィン１部、三酸化アンチモン１０部、カルナバワックス１．２部、γ−グリシドキシプロピルトリメトキシシラン１．５部、カーボンブラック１部、下記に示す溶融球状シリカ（Ｉ）４００部、溶融球状シリカ（ＩＩ）４００部、溶融球状シリカ（ＩＩＩ）８０部（但し、微細溶融シリカの添加量に応じて各シリカ（Ｉ）〜（ＩＩＩ）を等比率で減らし、無機質充填剤の全配合量（即ち、微細溶融シリカと溶融球状シリカの合計量）を同一の８８０部とする）を熱２本ロールにて均一に溶融混合し、冷却、粉砕してエポキシ樹脂組成物（実施例１〜６）を得た。
【００３９】
また、下記の予備混合をせず、通常の方法で各成分を混合して表２に示す組成のエポキシ樹脂組成物（比較例１〜３）を得た。
【００４０】
【表１】

【００４１】

溶融球状シリカ
（Ｉ）比表面積１．４ｍ^２／ｇ，平均粒径１５μｍの球状シリカ
（ＩＩ）比表面積２．５ｍ^２／ｇ，平均粒径１０μｍの球状シリカ
（ＩＩＩ）比表面積１０ｍ^２／ｇ，平均粒径１．０μｍの球状シリカ
予備混合方法
方法（１）：エポキシ樹脂、フェノール樹脂と上記微細溶融シリカを１１０〜１２０℃にて５〜１５分溶融混合し、冷却後粉砕する。
方法（２）：フェノール樹脂と上記微細溶融シリカを１１０〜１２０℃にて５〜１５分溶融混合し、冷却後粉砕する。
【００４２】
得られた組成物及びその硬化物につき、以下の諸試験を行った。結果を表２に示す。
（イ）スパイラルフロー
ＥＭＭＩ規格に準じた金型を使用して１７５℃、７０ｋｇ／ｃｍ^２の条件で測定した。
（ロ）溶融粘度
島津製作所社製の高化式フローテスターを用いて、ノズル寸法直径１ｍｍ×長さ１０ｍｍ、荷重１０ｋｇ、サンプル量３ｇ、温度１７５℃にてフローレートを測定し、最低溶融粘度を求めた。
（ハ）曲げ強さ及び曲げ弾性率
ＪＩＳ−Ｋ６９１１に準じて１８０℃、７０ｋｇ／ｃｍ^２、成形時間２分の条件で１０×４×１００ｍｍの曲げ試験片を成形し、１８０℃で４時間ポストキュアーしたものについて２１５℃で測定した。
（ニ）線膨張係数、ガラス転移温度
直径４ｍｍ、長さ１５ｍｍの試験片を用いて、ＴＭＡ法により毎分５℃の速さで昇温したときの値を測定した。
（ホ）接着性
４２アロイ板に直径１５ｍｍ、高さ５ｍｍの円筒成形品を１７５℃、７０ｋｇ／ｃｍ^２、成形時間２分の条件で成形し、１８０℃で４時間ポストキュアーした後、プッシュプルゲージで成形物と４２アロイ板との剥離量を測定した。
（ヘ）吸湿後の耐半田クラック性（耐リフロー性）
７×７×０．４ｍｍの大きさのシリコーンチップを１０×１４×１．４ｍｍの大きさのＱＦＰ用リードフレーム（４２アロイ）に接着し、これにエポキシ樹脂組成物を成形条件１７５℃、７０ｋｇ／ｃｍ^２、成形時間２分で成形し、１８０℃で４時間ポストキュアーした。これを８５℃／８５％ＲＨの雰囲気に４８時間及び７２時間放置した後、２４０℃の半田浴に３０秒間浸漬し、パッケージクラック数／総数を測定した。
（ト）耐湿性
４ＭＲＡＭチップを２０ピンのＳＯＪフレームに接着し、これにエポキシ樹脂組成物を成形条件１７５℃、７０ｋｇ／ｃｍ^２、成形時間２分で成形し、１８０℃で４時間ポストキュアーした。これを１２１℃／１００％ＲＨの雰囲気に２４時間放置して吸湿させた後、２６０℃の半田浴に１０秒間浸漬し、更に１２１℃／１００％ＲＨ雰囲気中に３００時間放置したときのＡｌ配線断線数／総数を測定した。
（チ）吸水率
成形時間１７５℃、７０ｋｇ／ｃｍ^２、成形時間２分の条件で成形し、１８０℃で４時間ポストキュアーした直径５０ｍｍ、厚さ２ｍｍの円板を１２１℃／１００％ＲＨの雰囲気に２４時間放置し、吸水率を測定した。
（リ）バリ特性
ＥＭＭＩ規格に準じた金型を使用して１７５℃、７０ｋｇ／ｃｍ^２の条件でスリット厚３０μｍでのバリ長さを測定した。
【００４３】
表２の結果より、本発明のエポキシ樹脂組成物は、流動性、バリ発生抑制といった成形性が良好であると共に、低吸湿性、耐リフロー性に優れた硬化物を与え、特に硬化物の封止で信頼性の高い半導体装置が得られることが確認された。
【００４４】
【表２】

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an epoxy resin composition that provides a cured product having high reliability when molding a surface-mount package, a manufacturing method thereof, and a semiconductor device sealed with the cured product.
[0002]
[Prior art and problems to be solved by the invention]
Currently, resin-encapsulated diodes, transistors, ICs, LSIs, and super LSIs are the mainstream in the semiconductor industry. Among them, epoxy resins, curing agents, and epoxy resin compositions containing various additives added to them are In general, the semiconductor device is often sealed with an epoxy resin composition because it is excellent in moldability, adhesiveness, electrical properties, mechanical properties, moisture resistance and the like as compared with other thermosetting resins.
[0003]
In recent years, these semiconductor devices have been increasingly integrated, and the chip dimensions have been increasing accordingly. On the other hand, the external dimensions of packages have been reduced in size and thickness in accordance with demands for downsizing and weight reduction of electronic devices. Furthermore, as for the method of attaching the semiconductor component to the circuit board, the surface mounting of the semiconductor component has been widely performed in order to increase the density of the component on the substrate.
[0004]
However, when the semiconductor device is surface-mounted, it is common to immerse the entire semiconductor device in a solder bath or pass it through a high-temperature zone where the solder melts. Or peeling occurs at the interface between the lead frame or chip and the sealing resin. Such cracks and delamination become even more prominent when the sealing resin layer of the semiconductor device absorbs moisture before the thermal shock during surface mounting. Is being considered.
[0005]
Furthermore, in order to reliably fill a thin package or the like, the sealing resin must have a low viscosity, and burr generation during molding may cause continuous moldability, mold contamination, unfilled, etc. The reliability during molding may be greatly impaired.
[0006]
For this reason, as a means for coping with these problems, there are known methods such as adding silica having various particle diameters to the epoxy resin composition or using a high viscosity epoxy resin or phenol resin. In the method, a decrease in fluidity, a decrease in solder reflow resistance, and the like are observed, and it is difficult to completely satisfy recent and increasingly sophisticated requirements for sealing semiconductor devices.
[0007]
The present invention has been made in view of the above circumstances, and by providing a cured product having good fluidity and excellent solder reflow resistance and moldability of a surface mounting package, and sealing with the cured product. An object of the present invention is to provide an epoxy resin composition that provides a highly reliable semiconductor device, a manufacturing method thereof, and a semiconductor device sealed with a cured product of the composition.
[0008]
Means for Solving the Problem and Embodiment of the Invention
As a result of intensive studies to achieve the above object, the inventor of the present invention has an epoxy resin composition containing an epoxy resin, a curing agent, and an inorganic filler. As an inorganic filler, 97% by weight or more has a particle size of 25 μm or less. And the average particle size is less than 2.5 μm, and the mixture containing fine fused silica that has been uniformly mixed with an epoxy resin and / or a curing agent in advance in the total inorganic filler is used at least 1% by weight. Fine fused silica, which has a large surface area, small specific gravity, and is difficult to disperse uniformly with resin components such as epoxy resin and phenol resin by simple compounding, can be mixed uniformly with the above resin components, which results in good fluidity In addition, it can suppress the generation of burrs during molding, has excellent moldability, and has low moisture absorption and excellent solder reflow resistance for surface mounting packages. It has been found that an epoxy resin composition giving a product can be obtained, and that a highly reliable semiconductor device can be manufactured with high productivity by sealing with the cured product, and the present invention has been made.
[0009]
Accordingly, the present invention is an epoxy resin, a curing agent, in the epoxy resin composition containing a curing catalyst and inorganic fillers, the following general formula as the epoxy resin (1)
[Chemical 6]

(In the formula, R is a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and q is an integer of 0 to 5)
A resin containing 20% by weight or more of the epoxy resin represented by the formula is used, and as a curing agent, a phenol novolac resin, a resol type phenol resin, a triphenol alkane type resin, a polyfunctional type phenol resin, a dicyclopentadiene type phenol A phenol resin selected from a resin, a naphthalene ring-containing phenol resin, and a phenol aralkyl resin is used. As an inorganic filler, 97% by weight or more has a particle size of 25 μm or less and an average particle size of less than 2.5 μm. Uses an inorganic filler containing spherical fused silica containing 1 to 50% by weight of fine fused silica that has been uniformly melt- mixed with only the resin and / or curing agent in the total inorganic filler , and having an average particle size of 3 to 15 μm. An epoxy resin composition is provided.
Moreover, this invention is a method of manufacturing the epoxy resin composition containing an epoxy resin, a hardening | curing agent, a hardening catalyst, and an inorganic filler, and is represented by following General formula (1) as an epoxy resin.
[Chemical 7]

(In the formula, R is a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and q is an integer of 0 to 5)
In addition to the epoxy resin represented by the formula (1) containing at least 20% by weight of the total epoxy resin, as a curing agent, phenol novolac resin, resol type phenol resin, triphenol alkane type resin, polyfunctional type phenol resin, dicyclopentadiene type phenol Fine fused silica using a phenol resin selected from a resin, a naphthalene ring-containing phenol resin, and a phenol aralkyl resin, and having 97% by weight or more and a particle size of 25 μm or less and an average particle size of less than 2.5 μm as an inorganic filler Is used in an inorganic filler containing 1 to 50% by weight in the total inorganic filler and containing spherical fused silica having an average particle diameter of 3 to 15 μm, and the fine fused silica is used only as an epoxy resin and / or a curing agent. It is characterized in that it is uniformly melt-mixed in advance and mixed with the remaining ingredients. To provide a process for the preparation of the epoxy resin composition.
Furthermore, this invention provides the semiconductor device sealed with the hardened | cured material of the epoxy resin composition.
[0010]
Hereinafter, the present invention will be described in more detail. The epoxy resin composition of the present invention comprises an epoxy resin, a curing agent and an inorganic filler as essential components.
[0011]
Here, as an epoxy resin, as long as it is a compound having at least two epoxy groups in its molecule, the molecular structure, molecular weight, etc. are not particularly limited. Specifically, phenol novolac type epoxy resin, biphenyl type epoxy resin, Examples include bisphenol-type epoxy resins, aralkyl-type epoxy resins, polyfunctional epoxy resins, dicyclopentadiene-containing epoxy resins, naphthalene ring-containing epoxy resins, heterocyclic epoxy resins, and epoxy resins having halogen atoms introduced therein. it can.
[0012]
In the present invention, it is preferable to use a biphenyl type epoxy resin represented by the following general formula (1) as the epoxy resin.
[0013]
[Chemical formula 2]

(In the formula, R is a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and q is an integer of 0 to 5)
[0014]
In the above formula (1), R represents a hydrogen atom, a bromine atom, a chlorine atom, a halogen atom such as a fluorine atom, an alkyl having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group. Groups.
[0015]
The blending amount of the biphenyl type epoxy resin of the formula (1) is preferably 20% by weight or more, particularly 50% by weight or more of the whole epoxy resin to be blended in the composition. If the blending amount of the biphenyl type epoxy resin of the formula (1) is less than 20% by weight, low moisture absorption may not be obtained, crack resistance at the time of thermal shock after moisture absorption is not sufficiently improved, and high flow Therefore, the moldability and the curing characteristics may be inferior.
[0016]
Then, as the curing agent, as long as in 1 minute is a compound having a functional group reactive with two or more epoxy groups, molecular structure, molecular weight is not particularly limited, full E Nord novolak resin, resol type phenolic resins, tri Examples include phenolalkane type resins, polyfunctional phenolic resins, dicyclopentadiene type phenolic resins, naphthalene ring-containing phenolic resins, phenol aralkyl resins, etc. Among these, naphthalene ring-containing phenolic resins and phenolaralkyl resins are preferably used. The
[0017]
Examples of the naphthalene ring-containing phenol resin and phenol aralkyl resin include the following compounds.
[0018]
[Chemical 3]

(However, R ¹ represents a hydrogen atom, a halogen atom such as chlorine or bromine, or an alkyl group having 1 to 5 carbon atoms, m is an integer of 0 to 3, k and g are 0 or an integer of 1 or more, and p is 1. (It is an integer above.)
[0019]
[Formula 4]

[0020]
Here, the blending amount of the naphthalene ring-containing phenol resin and the phenol aralkyl resin is 10 to 100% of the total phenol resin (% by weight, the same applies hereinafter), preferably 10 to 90%, particularly preferably 20 to 70%, If the blending amount is less than 10%, low hygroscopicity may not be obtained.
[0021]
In the present invention, the compounding amount of the curing agent is a normal dose, but when a phenol resin is used as the curing agent, the molar amount of the epoxy group (a) and the phenolic hydroxyl group (b) in the total epoxy resin. The ratio is preferably (a) / (b) = 0.5 to 1.5, particularly 0.8 to 1.2, and if the ratio is out of the above range, curability, crack resistance, moisture absorption May be inferior.
[0022]
In the present invention, a curing catalyst can be blended. As the curing catalyst, the molecular weight and molecular structure are not particularly limited as long as they promote the reaction between the epoxy resin and the curing agent. Examples thereof include imidazole compounds, amine-based curing accelerators, and phosphorus-based compounds. In order to obtain a highly functional epoxy resin composition, it is desirable to use a phosphorus compound. The amount of the curing catalyst is not particularly limited, but is 0.2 to 5 parts, particularly 0.4 to 3 parts, with respect to 100 parts (parts by weight, the same applies hereinafter) of the epoxy resin and the curing agent. It is preferable.
[0023]
As the inorganic filler used in the present invention, a fine fused silica having a particle diameter of 25% or less and an average particle diameter of less than 2.5 μm, which is uniformly mixed with an epoxy resin and / or a curing agent in advance. Using at least 1% or more of the total inorganic filler.
[0024]
Here, as the fine fused silica, 97% or more, preferably 98 to 100%, has a particle size of 25 μm or less, and an average particle size (for example, as a weight average by X-ray diffraction method) is less than 2.5 μm, preferably 0 0.1 to 2.4 μm, more preferably about 0.5 to 2.2 μm is used. If it is out of this range, the fluidity is lowered or the generation of burrs cannot be suppressed.
[0025]
In the present invention, the fine fused silica is preliminarily mixed with an epoxy resin and / or a curing agent. In this case, it is preferable that the uniform mixing treatment is performed by mixing at 100 to 120 ° C. with a hot roll, a kneader, an extruder or the like after sufficiently mixing with a mixer or the like.
[0026]
The treated fine fused silica is required to be contained in the total inorganic filler at least 1% or more, usually 1 to 50%, preferably 3 to 25%, more preferably 5 to 15%. If the content of the fine fused silica is less than 1%, the fluidity is lowered or the generation of burrs cannot be suppressed.
[0027]
Further, the blending amount of the fine fused silica is preferably in the range of 1 to 15%, particularly 2 to 7% of the whole composition from the viewpoint of fluidity and generation of burrs.
[0028]
Normally, fine fused silica has a large specific surface area and a small specific gravity. Therefore, it is difficult to disperse uniformly with other components, particularly with resin components such as epoxy resins and phenol resins, by simple blending. For this reason, when finely fused silica is simply compounded, there are cases where sufficient fluidity, suppression of burr generation, and solder reflow resistance may not be obtained. When a filler is used, these problems can be solved, and an epoxy resin composition that gives a cured product having good fluidity, excellent moldability and solder reflow resistance can be obtained.
[0029]
In this invention, what is normally mix | blended with an epoxy resin composition can be used as inorganic fillers other than the said fine fused silica. Specific examples include crystalline silica, fused silica, aluminum nitride, silicon nitride, silicon carbide, alumina, boron nitride, titanium oxide, and glass fiber. Among these, fused silica is preferable.
[0030]
The average particle diameter and shape of these inorganic fillers are not particularly limited, but those having an average particle diameter of 3 to 15 μm are preferable, and spherical ones are preferably used in order to achieve high filling and reduce stress on the chip surface. . In order to increase the bond strength between the resin and the surface of the inorganic filler, it is recommended to use a surface treatment with a coupling agent such as a silane coupling agent or a titanate coupling agent. And it is preferable at the point which improves crack resistance.
[0031]
The total amount of the inorganic filler including the fine fused silica described above is not particularly limited, but may be in the range of 100 to 1300 parts, particularly 200 to 900 parts with respect to 100 parts of the total amount of the epoxy resin and the curing agent. preferable.
[0032]
In the composition of the present invention, various other additives can be further blended as necessary, as long as the object of the present invention is not adversely affected. Additives are appropriately selected according to the application, for example, low stress agents such as thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers, silicone metal salts, waxes such as carnauba wax, fatty acids such as stearic acid, Release agents such as esters and metal salts, pigments such as carbon black, cobalt blue, and bengara, flame retardants such as antimony oxide and halogen compounds, silane coupling agents such as glycidoxypropyltrimethoxysilane, alkyl titanates 1 type, or 2 or more types of surface treatment agents, such as an anti-aging agent, and other additives can be mix | blended.
[0033]
As a general method for preparing the epoxy resin composition of the present invention as a molding material, the above essential components and other additives are blended in a predetermined composition ratio, and after sufficiently mixing them with a mixer or the like, It can be melt-mixed by a hot roll, a kneader, an extruder or the like, then cooled and solidified, and pulverized to an appropriate size to obtain a molding material. The molding material thus obtained can be used for sealing and covering electronic components such as semiconductor devices or electrical components, thereby imparting excellent reliability under high temperature and high humidity.
[0034]
The semiconductor device of the present invention can be easily manufactured by sealing a semiconductor element using the above-described sealing resin composition. Here, examples of the semiconductor element to be sealed include an integrated circuit, an arithmetic circuit, a transistor, a thyristor, and a diode, but are not particularly limited. The most common method of sealing includes a transfer molding method. In this case, it is desirable that the molding temperature of the epoxy resin composition is 150 to 180 ° C. for 30 to 180 seconds, and the post cure is 150 to 180 ° C. for 2 to 16 hours.
[0035]
The epoxy resin composition is preferably post-cured by further heating after molding. Here, the post-curing is desirably performed under heating conditions of 150 ° C. or higher.
[0036]
【The invention's effect】
The epoxy resin composition of the present invention has good moldability such as fluidity and suppression of burr generation, and gives a cured product having low moisture absorption and excellent reflow resistance. With the cured product of this epoxy resin composition, When a package such as an LSI or a transistor is sealed, a highly reliable semiconductor product with excellent moldability can be manufactured with high productivity.
[0037]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, all the parts in each example are parts by weight.
[0038]
[Examples 1-6, Comparative Examples 1-3]
The epoxy resin shown in Table 1, the phenol resin and the fine fused silica shown below are used in the proportions shown in Table 2, and further premixed (1) or (2) is carried out by the following method, and triphenylphosphine 1 is used as a curing catalyst. Parts, antimony trioxide 10 parts, carnauba wax 1.2 parts, γ-glycidoxypropyltrimethoxysilane 1.5 parts, carbon black 1 part, fused spherical silica (I) 400 parts shown below, fused spherical silica ( II) 400 parts, fused spherical silica (III) 80 parts (however, depending on the addition amount of fine fused silica, each silica (I) to (III) is reduced at an equal ratio, and the total amount of inorganic filler (ie, The total amount of fine fused silica and fused spherical silica is 880 parts), and is uniformly melt-mixed with two hot rolls, cooled and pulverized to obtain an epoxy resin composition (Example 1 ) Was obtained.
[0039]
Moreover, the following preliminary mixing was not performed but each component was mixed by the normal method, and the epoxy resin composition (comparative examples 1-3) of the composition shown in Table 2 was obtained.
[0040]
[Table 1]

[0041]

Fused spherical silica (I) a specific surface area of 1.4 m ² / g, spherical silica (II) a specific surface area of 2.5 m ² / g with an average particle size of 15 [mu] m, average particle size 10μm of spherical silica (III) a specific surface area of ^{10 m} 2 / g , Spherical silica with an average particle size of 1.0 μm
Preliminary mixing method Method (1): An epoxy resin, a phenol resin and the above fine fused silica are melt-mixed at 110-120 [deg.] C. for 5-15 minutes, cooled and then pulverized.
Method (2): The phenol resin and the fine fused silica are melt-mixed at 110 to 120 ° C. for 5 to 15 minutes, cooled and pulverized.
[0042]
The following tests were performed about the obtained composition and its hardened | cured material. The results are shown in Table 2.
(I) Spiral flow Measurement was performed under the conditions of 175 ° C. and 70 kg / cm ² using a mold conforming to the EMMI standard.
(B) Melt viscosity Using an elevated flow tester manufactured by Shimadzu Corporation, measure the flow rate at a nozzle size of diameter 1 mm x length 10 mm, load 10 kg, sample amount 3 g, temperature 175 ° C, and determine the minimum melt viscosity. Asked.
(C) Bending strength and flexural modulus According to JIS-K6911, a 10 × 4 × 100 mm bending test piece was molded under conditions of 180 ° C., 70 kg / cm ² and a molding time of 2 minutes, and post-molded at 180 ° C. for 4 hours. The cured product was measured at 215 ° C.
(D) Using a test piece having a linear expansion coefficient, a glass transition temperature diameter of 4 mm, and a length of 15 mm, the value when the temperature was raised at a rate of 5 ° C. per minute by the TMA method was measured.
(E) Adhesive 42A cylindrical plate with a diameter of 15 mm and a height of 5 mm was formed on an alloy plate under conditions of 175 ° C., 70 kg / cm ² and a molding time of 2 minutes, post-cured at 180 ° C. for 4 hours, and then push-pull. The amount of peeling between the molded product and the 42 alloy plate was measured with a gauge.
(F) Solder crack resistance after moisture absorption (Reflow resistance)
A 7 × 7 × 0.4 mm silicone chip was bonded to a 10 × 14 × 1.4 mm QFP lead frame (42 alloy), and an epoxy resin composition was molded at 175 ° C. under a 70 kg condition. / Cm ² , molding with a molding time of 2 minutes, and post-curing at 180 ° C. for 4 hours. This was left in an atmosphere of 85 ° C./85% RH for 48 hours and 72 hours, then immersed in a solder bath at 240 ° C. for 30 seconds, and the number of package cracks / total number was measured.
(G) A moisture-resistant 4MRAM chip was bonded to a 20-pin SOJ frame, and an epoxy resin composition was molded on the molding conditions at 175 ° C. and 70 kg / cm ^{2 under} a molding time of 2 minutes, and post-cured at 180 ° C. for 4 hours. . This is left in an atmosphere of 121 ° C./100% RH for 24 hours to absorb moisture, then immersed in a solder bath at 260 ° C. for 10 seconds, and further left in an atmosphere of 121 ° C./100% RH for 300 hours. The number of disconnections / total number was measured.
(H) Water absorption rate molding time 175 ° C., 70 kg / cm ² , molding was performed under the conditions of molding time 2 minutes, and a post-cured disc at 180 ° C. for 4 hours with a diameter of 50 mm and a thickness of 2 mm was 121 ° C./100% RH. After standing in the atmosphere for 24 hours, the water absorption was measured.
(Li) Burr characteristics Using a mold conforming to the EMMI standard, the burr length at a slit thickness of 30 μm was measured at 175 ° C. and 70 kg / cm ² .
[0043]
From the results of Table 2, the epoxy resin composition of the present invention has good moldability such as fluidity and suppression of burr generation, and gives a cured product having excellent low moisture absorption and reflow resistance. It was confirmed that a highly reliable semiconductor device can be obtained without stopping.
[0044]
[Table 2]

Claims (3)

In an epoxy resin composition containing an epoxy resin, a curing agent , a curing catalyst, and an inorganic filler, the following general formula (1) is used as an epoxy resin.

(In the formula, R is a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and q is an integer of 0 to 5)
A resin containing 20% by weight or more of the epoxy resin represented by the formula is used, and as a curing agent, a phenol novolac resin, a resol type phenol resin, a triphenol alkane type resin, a polyfunctional type phenol resin, a dicyclopentadiene type phenol A phenol resin selected from a resin, a naphthalene ring-containing phenol resin, and a phenol aralkyl resin is used. As an inorganic filler, 97% by weight or more has a particle size of 25 μm or less and an average particle size of less than 2.5 μm. Uses an inorganic filler containing spherical fused silica containing 1 to 50% by weight of fine fused silica that has been uniformly melt- mixed with only the resin and / or curing agent in the total inorganic filler , and having an average particle size of 3 to 15 μm. An epoxy resin composition characterized by comprising: In the method for producing an epoxy resin composition containing an epoxy resin, a curing agent, a curing catalyst and an inorganic filler, the following general formula (1) is used as the epoxy resin.

(In the formula, R is a hydrogen atom, a halogen atom or an alkyl group having 1 to 5 carbon atoms, and q is an integer of 0 to 5)
A resin containing 20% by weight or more of the epoxy resin represented by the formula is used, and as a curing agent, a phenol novolac resin, a resol type phenol resin, a triphenol alkane type resin, a polyfunctional type phenol resin, a dicyclopentadiene type phenol Fine fused silica using a phenol resin selected from a resin, a naphthalene ring-containing phenol resin, and a phenol aralkyl resin, and having 97% by weight or more and a particle size of 25 μm or less and an average particle size of less than 2.5 μm as an inorganic filler Is used in an inorganic filler containing 1 to 50% by weight of the total inorganic filler and containing spherical fused silica having an average particle diameter of 3 to 15 μm, and the fine fused silica is used only as an epoxy resin and / or a curing agent. It is characterized in that it is uniformly melt-mixed in advance and mixed with the remaining ingredients. Method for producing an epoxy resin composition. A semiconductor device sealed with a cured product of the epoxy resin composition according to claim 1.