JP4655403B2 - Epoxy resin composition and semiconductor device - Google Patents

Description

（Ｒは、炭素数１〜４のアルキル基）
【０００７】
（３）予めシランカップリング剤で処理された真円度０．４〜１．０の水酸化アルミニウム表面のシランカップリング剤の固着率が、７０〜１００％である第（１）項又は（２）項記載の半導体封止用エポキシ樹脂組成物、
（４）第（１）項〜（３）項のいずれかに記載のエポキシ樹脂組成物を用いて半導体素子を封止してなることを特徴とする半導体装置、
である。
【０００８】
【発明の実施の形態】
本発明に用いるエポキシ樹脂としては、１分子内にエポキシ基を２個以上有するモノマー、オリゴマー、ポリマー全般を言い、その分子量、分子構造を特に限定するものではないが、例えば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、スチルベン型エポキシ樹脂、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、トリフェノールメタン型エポキシ樹脂、アルキル変性トリフェノールメタン型エポキシ樹脂、ナフトール型エポキシ樹脂、トリアジン核含有エポキシ樹脂、ジシクロペンタジエン変性フェノール型エポキシ樹脂、フェノールアラルキル（フェニレン骨格、ジフェニレン骨格等を有する）型エポキシ樹脂等が挙げられ、これらは単独でも混合して用いても差し支えない。
【０００９】
本発明に用いるフェノール樹脂としては、１分子内にフェノール性水酸基を２個以上有するモノマー、オリゴマー、ポリマー全般を言い、その分子量、分子構造を特に限定するものではないが、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、ジシクロペンタジエン変性フェノール樹脂、テルペン変性フェノール樹脂、トリフェノールメタン型樹脂、フェノールアラルキル（フェニレン骨格、ジフェニレン骨格等を有する）樹脂やナフトールアラルキル（フェニレン骨格、ジフェニレン骨格等を有する）樹脂等が挙げられ、これらは単独でも混合して用いても差し支えない。これらの配合量としては、全エポキシ樹脂のエポキシ基数と全フェノール樹脂のフェノール性水酸基数の比が０．８〜１．３が好ましい。
【００１０】
本発明に用いる硬化促進剤としては、エポキシ基とフェノール性水酸基との硬化反応を促進させるものであればよく、一般に封止材料に使用するものを使用することができる。例えば１，８−ジアザビシクロ（５，４，０）ウンデセン−７、トリフェニルホスフィン、２−メチルイミダゾール、テトラフェニルホスホニウム・テトラフェニルボレート等が挙げられ、これらは単独でも混合して用いても差し支えない。
【００１１】
本発明に用いる無機充填材としては、一般に封止材料に使用されているものを使用することができる。例えば溶融シリカ、結晶シリカ、タルク、アルミナ、窒化珪素等が挙げられ、これらは単独でも混合して用いてもよい。特に溶融シリカが好ましい。
無機充填材の含有量としては、真円度０．４〜１．０の水酸化アルミニウムとの合計量が全エポキシ樹脂組成物中に７０〜９４重量％が好ましく、更に好ましくは８０〜９２重量％である。７０重量％未満だと吸水率の上昇に伴う耐半田クラック性が低下し、９４重量％を越えるとワイヤースィープ、チップシフト等の問題が起こるので好ましくない。
【００１２】
本発明に用いる水酸化アルミニウムは難燃剤として作用し、その難燃機構としては、燃焼時に水酸化アルミニウムが脱水を開始し、吸熱することによって燃焼反応を阻害するものである。又硬化した樹脂成分の炭化を促進することが知られており、硬化物表面に酸素を遮断する難燃層を形成すると考えられる。
水酸化アルミニウムの含有量としては、全エポキシ樹脂組成物中に１〜１５重量％が好ましく、更に好ましくは１〜１０重量％である。１重量％未満だと難燃性が不足し、１５重量％を越えると流動性や硬化性等の成形性、機械強度の低下や耐半田クラック性が悪化するので好ましくない。
【００１３】
水酸化アルミニウムの平均粒径としては、１〜３０μｍが好ましく、より好ましくは１〜１５μｍである。１μｍ未満ではエポキシ樹脂組成物の成形時の流動性が低下し、３０μｍを越えると難燃性が低下する。
次に粒形については、粒子の形状が球形に近いほど流動性向上の点で望ましい。下記式で示される真円度が０．４〜１．０であることが好ましく、真円度が０．４未満だと流動性が低下し、ワイヤースィープ、チップシフト等が起こるおそれがあり好ましくない。
真円度＝α／α’＝α×４π／（ＰＭ）²
ここで、αは、真円度算出の対象となる対象物（水酸化アルミニウム）１０ｇの投影像の実面積を示す。α’は、上記の投影像の周囲の長さ（＝ＰＭ）とした場合、周囲の長さがＰＭとなる真円の面積を指す。従って、真円度が１の場合、その対象物は真円である。そして対象物に凸凹があると、真円度は低下する。真円度の測定には、シスメックス株式会社のＦＰＩＰ−２１００を用いた。
【００１４】
本発明に用いられるシランカップリング剤は、通常エポキシ樹脂組成物の無機充填材と樹脂との界面の結合を強固にし、エポキシ樹脂組成物の硬化物の機械強度を向上させるものである。しかし、本発明では水酸化アルミニウムにシランカップリング剤を予め処理することにより、通常の無機充填材への効果以上の特徴が発現することが判明し、水酸化アルミニウムを使用するエポキシ樹脂組成物の特性向上が可能になる。即ち、水酸化アルミニウムを難燃剤として使用する場合、エポキシ樹脂組成物の硬化性が低下するのに対し、予め水酸化アルミニウムをシランカップリング剤で表面処理することにより、硬化性の低下が防止できる。これはエポキシ樹脂組成物の硬化反応中にエポキシ樹脂とフェノール樹脂の反応中間体に含まれるエポキシ基の開環物が水酸化アルミニウムと強く配位・安定化し、硬化反応を阻害するものと推定されているが、シランカップリング剤で予め表面処理することにより、この配位・安定化が起きにくくなるため、硬化反応が低下しないものと推定される。
【００１５】
本発明に用いるシランカップリング剤は、アミノ基、エポキシ基、メルカプト基等を含むシランカップリング剤全般を指し、水酸化アルミニウムを含むエポキシ樹脂組成物の硬化阻害を防止することから、一般式（１）〜一般（３）で示されるシランカップリング剤が好ましく、特にアミノ基を有するシランカップリング剤がエポキシ樹脂の反応を促進する効果を有するため最も好ましい。一般式（１）〜一般（３）の代表的なシランカップリング剤としては、γ−アミノプロピルトリエトキシシラン、β−（３，４−エポキシシクロヘキシル）エチルトリメトキシシラン、γ−グリシドキシプロピルトリメトキシシランが挙げられるがこれらに限定されるものではない。これらのシランカップリング剤は、単独でも混合して用いてもよい。
【００１６】
又水酸化アルミニウムは、前述したように真円度が大きい方がエポキシ樹脂組成物の成形時の流動性が向上するが、一方真円度が大きいほど、硬化物の機械強度の低下や、耐半田クラック性の悪化の傾向がある。この強度低下を防止するためにもシランカップリング剤で水酸化アルミニウムの表面を予め処理することは有効であり、同様に一般式（２）〜一般式（４）で示されるシランカップリング剤が特にこの目的のためにも有効である。
【００１７】
シランカップリング剤による水酸化アルミニウムの処理方法としては、スーパーミキサー等に水酸化アルミニウムを投入し、攪拌しながらシランカップリング剤を均一に噴霧し、攪拌を継続することで表面処理が可能である。又はエポキシ樹脂組成物の製造工程において、無機充填材と水酸化アルミニウムの混合物にシランカップリング剤を添加して、一定時間攪拌後、その後他の成分を逐次添加しても構わない。特に効果的な表面処理方法としては、シランカップリング剤を噴霧後、５０〜２００℃の加熱処理を施す工程を加えることによりシランカップリング剤が水酸化アルミニウム表面に効果的に反応し、水酸化アルミニウム表面に固着させることができる。
【００１８】
シランカップリング剤の固着率としては７０〜１００％が好ましい。固着率は、シランカップリング剤が物理的吸着或いは化学的結合かを評価するため、処理後の水酸化アルミニウムをメタノールで洗浄したものと未洗浄のものについて元素分析を行い、炭素元素を定量し、添加したシランカップリング剤に由来する炭素元素の残存率を求めたものである。
固着率（％）＝（メタノール洗浄後の炭素元素量）／（メタノール洗浄前の炭素元素量）×１００
７０％未満では、エポキシ樹脂組成物の硬化性低下の防止効果が不十分であり、又エポキシ樹脂組成物の硬化後の機械強度低下の防止効果が不十分である。
【００１９】
本発明のエポキシ樹脂組成物は、（Ａ）〜（Ｆ）成分を必須成分とするが、これ以外に必要に応じて、カップリング剤、カーボンブラック等の着色剤、天然ワックス、合成ワックス等の離型剤、シリコーンオイル、ゴム等の低応力添加剤等の種々の添加剤を適宜配合しても差し支えない。
又本発明のエポキシ樹脂組成物は、（Ａ）〜（Ｆ）成分、及びその他の添加剤等をミキサー等を用いて充分に均一に混合した後、更に熱ロール又はニーダー等で溶融混練し、冷却後粉砕して得られる。
本発明のエポキシ樹脂組成物を用いて、半導体素子等の各種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従来からの成形方法で硬化成形すればよい。
【００２０】
【実施例】
以下に本発明の実施例を示すが、本発明はこれらに限定されるものではない。
配合割合は重量部とする。
実施例１
表１に示す性状の水酸化アルミニウムＡ１００重量部をスーパーミキサー中で攪拌しながら、γ−グリシドキシプロピルトリメトキシシラン０．２重量部、γ−アミノプロピルトリエトキシシラン０．３重量部を均一に噴霧し、１５分間攪拌を継続した。続いて１５０℃で３時間加熱した。この処理された水酸化アルミニウムの炭素元素の元素分析を行ったところ、固着率は９６％であった。この処理された水酸化アルミニウムを処理水酸化アルミニウムＡと言う。
ビフェニル型エポキシ樹脂（融点１０５℃、エポキシ当量１９５：ジャパンエポキシレジン（株）製、ＹＸ−４０００） ７．６重量部
フェノールアラルキル樹脂（軟化点７９℃、水酸基当量１７５：三井化学（株
）製、ＸＬＣ−ＬＬ） ６．９重量部
１，８−ジアザビシクロ（５，４，０）ウンデセン−７（以下、ＤＢＵという
） ０．２重量部
溶融球状シリカ（平均粒径２５μｍ） ７７．０重量部
処理水酸化アルミニウムＡ ７．５重量部
カーボンブラック ０．３重量部
カルナバワックス ０．５重量部
を常温でスーパーミキサーを用いて混合し、７０〜１００℃でロール混練し、冷却後粉砕してエポキシ樹脂組成物を得た。得られたエポキシ樹脂組成物を以下の方法で評価した。結果を表２に示す。
【００２１】
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金型を用いて、金型温度１７５℃、注入圧力６．９ＭＰａ、硬化時間１２０秒で測定した。
チップシフト量：３２ピンのＬｅａｄ Ｏｎ Ｃｈｉｐ構造ＴＳＯＰ（パッケージサイズは１０ｍｍ×２１ｍｍ、厚み１．０ｍｍ、シリコンチップサイズは９ｍｍ×１８ｍｍ、リードフレームは４２アロイ製、チップとインナーリード間は厚み１００μｍのポリイミドテープで接着されている）を金型温度１７５℃、注入圧力７５ｋｇ／ｃｍ²、硬化時間２分でトランスファー成形を行った。成形品を樹脂組成物の注入方向に沿ってパッケージ中心で切断し、断面を観察することでチップ両端のパッケージ成形品下面からの距離を求め、その差をチップシフト量としてμｍ単位で表示した。
硬化性：（株）オリエンテック製、キュラストメーターＶ型を用いて、ダイスの直径３５ｍｍ、成形温度１７５℃、成形開始９０秒後のトルク値を測定した。
単位はｋｇｆ・ｃｍ。
熱時曲げ強度：ＪＩＳ Ｋ ６９１１に準じて（２４０℃で）測定した。単位はＮ／ｍｍ²。
難燃性：低圧トランスファー成形機を用いて、成形温度１７５℃、注入圧力７０ｋｇ／ｃｍ²、硬化時間１２０秒で試験片（１２７ｍｍ×１２．７ｍｍ×３．２ｍｍ）を成形し、アフターベークとして１７５℃、８時間処理した後、ＵＬ−９４垂直法に準じてΣＦ、Ｆmaxを測定し、難燃性を判定した。
高温保管特性：模擬素子を２５μｍ径の金線で配線した１６ピンＳＯＰを、金型温度１７５℃、注入圧力７０ｋｇ／ｃｍ²、硬化時間１２０秒でトランスファー成形し、１７５℃、８時間でアフターベークした。１８５℃の恒温槽で処理し、一定時間毎にピン間の抵抗値を測定した。初期の抵抗値から１０％以上抵抗値が増大したパッケージ数が、１５個中８個以上になった恒温槽処理時間を高温保管特性として表示した。この時間が長いと、高温安定性に優れていることを示す。単位は時間。
耐半田クラック性：低圧トランスファー成形機を用いて、成形温度１７５℃、注入圧力７０ｋｇ／ｃｍ²、硬化時間１２０秒で、８０ｐＱＦＰ（厚さ２ｍｍ、チップサイズ９．０ｍｍ×９．０ｍｍ）を成形し、アフターベークとして１７５℃、８時間処理した後、８５℃、相対湿度８５％で９６時間の処理を行い、ＩＲリフロー処理（２４０℃、１０秒）を行った。超音波探傷機を用いて、パッケージ内部の剥離、クラック等の不良を観察した。６個のパッケージ中の不良パッケージ数を示す。
【００２２】
実施例２、３、比較例１〜４
表２の配合に従い、実施例１と同様にしてエポキシ樹脂組成物を得て、実施例１と同様にして評価した。結果を表２に示す。
実施例２に用いた処理水酸化アルミニウムＢは、表１に示す性状の水酸化アルミニウムＢ１００重量部をスーパーミキサー中で攪拌しながら、γ−グリシドキシプロピルトリメトキシシラン０．２重量部、γ−アミノプロピルトリエトキシシラン０．３重量部を均一に噴霧し、１５分間攪拌を継続した。続いて１５０℃で３時間加熱し、その後処理された水酸化アルミニウム１０重量部とメタノール１００重量部を超音波洗浄機で３０分間処理した後、８０℃で１時間乾燥した。この処理された水酸化アルミニウムの炭素元素の元素分析を行ったところ、固着率は９２％であった。
【００２３】
実施例３に用いた処理溶融球状シリカ−水酸化アルミニウムＡは、平均粒径２５μｍの溶融球状シリカ７７．０重量部と表１に示す性状の水酸化アルミニウムＡ７．０重量部をスーパーミキサー中で攪拌しながら、γ−グリシドキシプロピルトリメトキシシラン０．２重量部、γ−アミノプロピルトリエトキシシラン０．３重量部を均一に噴霧し、１５分間攪拌を継続した。続いて１５０℃で３時間加熱し、その後処理された処理溶融球状シリカ−水酸化アルミニウム１００重量部とメタノール１０００重量部を超音波洗浄機で３０分間処理した後、８０℃で１時間乾燥した。この処理された溶融球状シリカ−水酸化アルミニウムの炭素元素の元素分析を行ったところ、固着率は８５％であった。
【００２４】
比較例１に用いた処理水酸化アルミニウムＣは、表１に示す性状の水酸化アルミニウムＣ１００重量部をスーパーミキサー中で攪拌しながら、γ−グリシドキシプロピルトリメトキシシラン０．２重量部、γ−アミノプロピルトリエトキシシラン０．３重量部を均一に噴霧し、１５分間攪拌を継続した。続いて１５０℃で３時間加熱し、その後処理された水酸化アルミニウム１０重量部とメタノール１００重量部を超音波洗浄機で３０分間処理した後、８０℃で１時間乾燥した。この処理された水酸化アルミニウムの炭素元素の元素分析を行ったところ、固着率は８７％であった。
【００２５】
比較例２に用いた処理水酸化アルミニウムＤは、表１に示す性状の水酸化アルミニウムＣ１００重量部をスーパーミキサー中で攪拌しながら、γ−グリシドキシプロピルトリメトキシシラン０．２重量部、γ−アミノプロピルトリエトキシシラン０．３重量部を均一に噴霧し、３分間攪拌を継続した。その後処理された水酸化アルミニウム１０重量部とメタノール１００重量部を超音波洗浄機で３０分間処理した後、８０℃で１時間乾燥した。この処理された水酸化アルミニウムの炭素元素の元素分析を行ったところ、固着率は２３％であった。
比較例３に用いたシランカップリング剤はγ−アミノプロピルトリエトキシシラン、γ−グリシドキシプロピルトリメトキシシランである。
比較例４に用いた処理溶融球状シリカは、溶融球状シリカ７７重量部をスーパーミキサー中で攪拌しながら、γ−グリシドキシプロピルトリメトキシシラン０．２重量部、γ−アミノプロピルトリエトキシシラン０．３重量部を均一に噴霧し、１５分間攪拌を継続した。続いて１５０℃で３時間加熱し、その後処理された処理溶融球状シリカ１００重量部とメタノール１０００重量部を超音波洗浄機で３０分間処理した後、８０℃で１時間乾燥した。この処理された溶融球状シリカの炭素元素の元素分析を行ったところ、固着率は７２％であった。比較例３、４に用いた水酸化アルミニウムＡの性状は、表１のものである。
【００２６】
【表１】

【００２７】
【表２】

【００２８】
【発明の効果】
本発明に従うと、ハロゲン系難燃剤及びアンチモン化合物を含まず、流動性、硬化性等の成形性、熱時強度に優れた特性を有する半導体封止用エポキシ樹脂組成物が得られ、これを用いた半導体装置は耐半田クラック性に優れている。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an epoxy resin composition for semiconductor encapsulation and a semiconductor device, which do not contain a halogen-based flame retardant and an antimony compound, and have excellent curability and flame retardancy.
[0002]
[Prior art]
Conventionally, electronic components such as diodes, transistors, and integrated circuits are mainly sealed with an epoxy resin composition. In these epoxy resin compositions, a halogen-based flame retardant and an antimony compound are usually blended in order to impart flame retardancy. However, with the growing awareness of environmental protection worldwide, there are concerns about the environmental impact of halogenated flame retardants and antimony compounds. Without using any of these, epoxy resin compositions with excellent flame resistance Development is required.
When a semiconductor device sealed with an epoxy resin composition containing a halogenated flame retardant and an antimony compound is stored at a high temperature, halides and antimony compounds released by thermal decomposition from these flame retardant components are bonded to the semiconductor element. Epoxy that is known to corrode parts and impair the reliability of semiconductor devices, and can achieve V-0 flame retardant grade without using halogen flame retardant and antimony compound as flame retardant There is a need for resin compositions.
[0003]
In this way, the corrosion resistance of the semiconductor element junction (bonding pad) after storing the semiconductor device at a high temperature (for example, 185 ° C.) is called the high temperature storage characteristic, and this high temperature storage characteristic is improved. As a technique for achieving this, a method using diantimony pentoxide (Japanese Patent Laid-Open No. 55-146950), a method of combining antimony oxide and an organic phosphine (Japanese Patent Laid-Open No. 61-53321), and the like have been proposed. However, there are some types of epoxy resin compositions that are unsatisfactory for the required level of high-temperature storage characteristics for recent semiconductor devices. Therefore, the development of an epoxy resin composition that does not use any halogen-based flame retardant and antimony compound is also required from the viewpoint of high-temperature storage characteristics.
From these viewpoints, a method of adding aluminum hydroxide as a conventional flame retardant has been proposed. The addition of a large amount maintains flame retardancy, and there is no problem in high-temperature storage characteristics. There existed a problem that the fluidity | liquidity at the time of shaping | molding of a resin composition, sclerosis | hardenability, the mechanical strength of hardened | cured material fell, and the deterioration of solder crack-proof property.
That is, an epoxy resin composition that maintains flame retardancy and is well-balanced in formability such as fluidity and curability, high-temperature storage characteristics and solder crack resistance without using halogen-based flame retardants and antimony compounds. Is required.
[0004]
[Problems to be solved by the invention]
The present invention provides an epoxy resin composition for semiconductor encapsulation which does not contain a halogen-based flame retardant and an antimony compound and has excellent moldability such as fluidity and curability, and a semiconductor device excellent in flame retardancy and high-temperature storage characteristics. Is.
[0005]
[Means for Solving the Problems]
The present invention
(1) (A) epoxy resin, (B) phenol resin, (C) curing accelerator, (D) inorganic filler, and (E) roundness previously treated with a silane coupling agent 0.4 to 1. An epoxy resin composition for encapsulating a semiconductor, characterized by comprising zero aluminum hydroxide,
(2) The epoxy resin composition for semiconductor encapsulation according to item (1), wherein the silane coupling agent is at least one selected from the general formula (1) to the general formula (3).
[0006]
[Chemical 2]

(R is an alkyl group having 1 to 4 carbon atoms)
[0007]
(3) Item (1) or (1), wherein the adhesion rate of the silane coupling agent on the surface of aluminum hydroxide having a roundness of 0.4 to 1.0 treated beforehand with a silane coupling agent is 70 to 100%. 2) epoxy resin composition for semiconductor encapsulation according to item
(4) A semiconductor device comprising a semiconductor element sealed with the epoxy resin composition according to any one of (1) to (3),
It is.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The epoxy resin used in the present invention includes monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule, and its molecular weight and molecular structure are not particularly limited. For example, biphenyl type epoxy resin, bisphenol Type epoxy resin, stilbene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, naphthol type epoxy resin, triazine nucleus-containing epoxy resin, dicyclo Examples thereof include a pentadiene-modified phenol type epoxy resin and a phenol aralkyl (having a phenylene skeleton, a diphenylene skeleton, etc.) type epoxy resin. These may be used alone or in combination.
[0009]
The phenol resin used in the present invention refers to monomers, oligomers, and polymers generally having two or more phenolic hydroxyl groups in one molecule, and its molecular weight and molecular structure are not particularly limited. For example, phenol novolak resin, Cresol novolak resin, dicyclopentadiene modified phenol resin, terpene modified phenol resin, triphenolmethane type resin, phenol aralkyl (having phenylene skeleton, diphenylene skeleton, etc.) resin, naphthol aralkyl (having phenylene skeleton, diphenylene skeleton, etc.) resin, etc. These may be used alone or in combination. As these compounding amounts, the ratio of the number of epoxy groups of all epoxy resins to the number of phenolic hydroxyl groups of all phenol resins is preferably 0.8 to 1.3.
[0010]
As a hardening accelerator used for this invention, what is necessary is just to accelerate | stimulate the hardening reaction of an epoxy group and a phenolic hydroxyl group, and what is generally used for a sealing material can be used. Examples thereof include 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, 2-methylimidazole, tetraphenylphosphonium / tetraphenylborate, etc., and these may be used alone or in combination. .
[0011]
As the inorganic filler used in the present invention, those generally used for sealing materials can be used. Examples thereof include fused silica, crystalline silica, talc, alumina, silicon nitride and the like, and these may be used alone or in combination. In particular, fused silica is preferable.
As the content of the inorganic filler, the total amount of aluminum hydroxide having a roundness of 0.4 to 1.0 is preferably 70 to 94% by weight, more preferably 80 to 92% by weight in the total epoxy resin composition. %. If it is less than 70% by weight, the resistance to solder cracking accompanying an increase in water absorption rate is lowered, and if it exceeds 94% by weight, problems such as wire sweep and chip shift occur, which is not preferable.
[0012]
The aluminum hydroxide used in the present invention acts as a flame retardant, and the flame retardant mechanism is that the aluminum hydroxide starts dehydration during combustion and absorbs heat, thereby inhibiting the combustion reaction. It is also known to promote carbonization of the cured resin component, and is considered to form a flame retardant layer that blocks oxygen on the surface of the cured product.
As content of aluminum hydroxide, 1 to 15 weight% is preferable in all the epoxy resin compositions, More preferably, it is 1 to 10 weight%. If it is less than 1% by weight, the flame retardancy is insufficient, and if it exceeds 15% by weight, moldability such as fluidity and curability, deterioration of mechanical strength and solder crack resistance are deteriorated, which is not preferable.
[0013]
As an average particle diameter of aluminum hydroxide, 1-30 micrometers is preferable, More preferably, it is 1-15 micrometers. If it is less than 1 μm, the fluidity at the time of molding the epoxy resin composition is lowered, and if it exceeds 30 μm, the flame retardancy is lowered.
Next, with regard to the particle shape, the closer the particle shape is to a spherical shape, the better in terms of improving fluidity. The roundness represented by the following formula is preferably 0.4 to 1.0, and if the roundness is less than 0.4, the fluidity may be lowered, and wire sweep, chip shift, etc. may occur. Absent.
Roundness = α / α ′ = α × 4π / (PM) ²
Here, α represents the actual area of the projected image of the object (aluminum hydroxide) 10 g that is the object of roundness calculation. α ′ indicates the area of a perfect circle having a perimeter of PM when the perimeter of the projection image (= PM). Therefore, when the roundness is 1, the object is a perfect circle. If the object has irregularities, the roundness decreases. For measuring the roundness, FPIP-2100 manufactured by Sysmex Corporation was used.
[0014]
The silane coupling agent used in the present invention usually strengthens the bond at the interface between the inorganic filler of the epoxy resin composition and the resin, and improves the mechanical strength of the cured product of the epoxy resin composition. However, in the present invention, it has been found that pretreatment of aluminum hydroxide with a silane coupling agent reveals characteristics more than those of ordinary inorganic fillers. The characteristics can be improved. That is, when aluminum hydroxide is used as a flame retardant, the curability of the epoxy resin composition is lowered, whereas the surface treatment of aluminum hydroxide with a silane coupling agent can prevent the lowering of the curability. . This is presumed that during the curing reaction of the epoxy resin composition, the ring-opened product of the epoxy group contained in the reaction intermediate between the epoxy resin and the phenol resin strongly coordinates and stabilizes with aluminum hydroxide and inhibits the curing reaction. However, the surface treatment with a silane coupling agent makes it difficult for this coordination / stabilization to occur, so it is presumed that the curing reaction does not decrease.
[0015]
The silane coupling agent used in the present invention refers to all silane coupling agents containing an amino group, an epoxy group, a mercapto group, etc., and prevents curing inhibition of an epoxy resin composition containing aluminum hydroxide. The silane coupling agent represented by 1) to General (3) is preferable, and the silane coupling agent having an amino group is most preferable because it has an effect of promoting the reaction of the epoxy resin. Typical silane coupling agents represented by the general formulas (1) to (3) include γ-aminopropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxypropyl. Examples include, but are not limited to, trimethoxysilane. These silane coupling agents may be used alone or in combination.
[0016]
As described above, aluminum hydroxide has a higher roundness to improve the fluidity during molding of the epoxy resin composition. On the other hand, the higher the roundness, the lower the mechanical strength of the cured product. There is a tendency for solder cracking to deteriorate. In order to prevent this reduction in strength, it is effective to pretreat the surface of aluminum hydroxide with a silane coupling agent. Similarly, the silane coupling agents represented by the general formulas (2) to (4) It is particularly effective for this purpose.
[0017]
As a method for treating aluminum hydroxide with a silane coupling agent, surface treatment is possible by introducing aluminum hydroxide into a super mixer, etc., spraying the silane coupling agent uniformly while stirring, and continuing stirring. . Or in the manufacturing process of an epoxy resin composition, after adding a silane coupling agent to the mixture of an inorganic filler and aluminum hydroxide and stirring for a fixed time, you may add another component sequentially after that. As a particularly effective surface treatment method, after spraying the silane coupling agent, a step of performing heat treatment at 50 to 200 ° C. is added so that the silane coupling agent effectively reacts with the surface of the aluminum hydroxide, and the hydroxylation is performed. It can be fixed to the aluminum surface.
[0018]
The sticking rate of the silane coupling agent is preferably 70 to 100%. In order to evaluate whether the silane coupling agent is physically adsorbed or chemically bonded, the sticking rate is determined by performing elemental analysis on the treated aluminum hydroxide washed with methanol and unwashed to quantify the carbon element. The residual ratio of the carbon element derived from the added silane coupling agent is obtained.
Fixing rate (%) = (Amount of carbon element after washing with methanol) / (Amount of carbon element before washing with methanol) × 100
If it is less than 70%, the effect of preventing the decrease in curability of the epoxy resin composition is insufficient, and the effect of preventing the decrease in mechanical strength after curing of the epoxy resin composition is insufficient.
[0019]
The epoxy resin composition of the present invention comprises the components (A) to (F) as essential components, but in addition to this, a coupling agent, a colorant such as carbon black, natural wax, synthetic wax, etc. Various additives such as a release agent, a low-stress additive such as silicone oil and rubber may be appropriately blended.
Moreover, the epoxy resin composition of the present invention, after sufficiently uniformly mixing the components (A) to (F) and other additives using a mixer or the like, is further melt-kneaded with a hot roll or a kneader, It is obtained by grinding after cooling.
The epoxy resin composition of the present invention is used to encapsulate various electronic components such as semiconductor elements, and to manufacture semiconductor devices by conventional molding methods such as transfer molding, compression molding, and injection molding. do it.
[0020]
【Example】
Examples of the present invention are shown below, but the present invention is not limited thereto.
The blending ratio is parts by weight.
Example 1
While stirring 100 parts by weight of aluminum hydroxide A having the properties shown in Table 1 in a super mixer, 0.2 parts by weight of γ-glycidoxypropyltrimethoxysilane and 0.3 parts by weight of γ-aminopropyltriethoxysilane were uniformly added. And stirring was continued for 15 minutes. Then, it heated at 150 degreeC for 3 hours. When the elemental analysis of the carbon element of this processed aluminum hydroxide was conducted, the adhesion rate was 96%. This treated aluminum hydroxide is referred to as treated aluminum hydroxide A.
Biphenyl type epoxy resin (melting point 105 ° C., epoxy equivalent 195: manufactured by Japan Epoxy Resin Co., Ltd., YX-4000) 7.6 parts by weight phenol aralkyl resin (softening point 79 ° C., hydroxyl group equivalent 175: manufactured by Mitsui Chemicals, Inc.) XLC-LL) 6.9 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 0.2 parts by weight fused spherical silica (average particle size 25 μm) 77.0 parts by weight Aluminum hydroxide A 7.5 parts by weight Carbon black 0.3 part by weight Carnauba wax 0.5 part by weight is mixed at room temperature using a super mixer, roll-kneaded at 70 to 100 ° C., cooled and pulverized to obtain an epoxy resin A composition was obtained. The obtained epoxy resin composition was evaluated by the following methods. The results are shown in Table 2.
[0021]
Evaluation Method Spiral Flow: Using a spiral flow measurement mold according to EMMI-1-66, measurement was performed at a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, and a curing time of 120 seconds.
Chip shift amount: 32-pin Lead On Chip structure TSOP (package size is 10 mm x 21 mm, thickness is 1.0 mm, silicon chip size is 9 mm x 18 mm, lead frame is 42 alloy, polyimide between chip and inner lead is 100 μm thick Transfer molding was performed at a mold temperature of 175 ° C., an injection pressure of 75 kg / cm ² , and a curing time of 2 minutes. The molded product was cut at the center of the package along the injection direction of the resin composition, and the distance from the lower surface of the package molded product at both ends of the chip was determined by observing the cross section, and the difference was displayed in μm units as the chip shift amount.
Curability: Using a Clastometer V type manufactured by Orientec Co., Ltd., the diameter of the die was 35 mm, the molding temperature was 175 ° C., and the torque value after 90 seconds from the start of molding was measured.
The unit is kgf · cm.
Hot bending strength: measured in accordance with JIS K 6911 (at 240 ° C.). The unit is N / mm ² .
Flame retardancy: Using a low-pressure transfer molding machine, a test piece (127 mm × 12.7 mm × 3.2 mm) was molded at a molding temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 120 seconds. After processing at ° C. for 8 hours, ΣF and Fmax were measured according to the UL-94 vertical method to determine flame retardancy.
High-temperature storage characteristics: 16-pin SOP in which a simulated element is wired with a 25 μm diameter gold wire is transfer molded at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² , a curing time of 120 seconds, and then baked at 175 ° C. for 8 hours. did. It processed in the thermostat of 185 degreeC, and measured the resistance value between pins for every fixed time. The constant-temperature bath treatment time when the number of packages whose resistance value increased by 10% or more from the initial resistance value was 8 or more out of 15 was displayed as the high temperature storage characteristics. When this time is long, it shows that it is excellent in high temperature stability. The unit is time.
Solder crack resistance: Using a low-pressure transfer molding machine, 80 pQFP (thickness 2 mm, chip size 9.0 mm × 9.0 mm) is molded at a molding temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 120 seconds. After baking at 175 ° C. for 8 hours as an after-bake, treatment was carried out at 85 ° C. and relative humidity of 85% for 96 hours, followed by IR reflow treatment (240 ° C., 10 seconds). Using an ultrasonic flaw detector, defects such as peeling and cracks inside the package were observed. The number of defective packages among the six packages is shown.
[0022]
Examples 2 and 3 and Comparative Examples 1 to 4
According to the composition of Table 2, an epoxy resin composition was obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 2.
The treated aluminum hydroxide B used in Example 2 was obtained by stirring 0.2 parts by weight of γ-glycidoxypropyltrimethoxysilane while stirring 100 parts by weight of aluminum hydroxide B having the properties shown in Table 1 in a super mixer. -0.3 part by weight of aminopropyltriethoxysilane was sprayed uniformly and stirring was continued for 15 minutes. Then, it heated at 150 degreeC for 3 hours, Then, 10 weight part of processed aluminum hydroxide and 100 weight part of methanol were processed for 30 minutes with the ultrasonic washing machine, Then, it dried at 80 degreeC for 1 hour. When the elemental analysis of the carbon element of this treated aluminum hydroxide was performed, the adhesion rate was 92%.
[0023]
The treated fused spherical silica-aluminum hydroxide A used in Example 3 was prepared by adding 77.0 parts by weight of fused spherical silica having an average particle size of 25 μm and 7.0 parts by weight of aluminum hydroxide A having the properties shown in Table 1 in a super mixer. While stirring, 0.2 part by weight of γ-glycidoxypropyltrimethoxysilane and 0.3 part by weight of γ-aminopropyltriethoxysilane were sprayed uniformly, and stirring was continued for 15 minutes. Subsequently, the mixture was heated at 150 ° C. for 3 hours, treated with 100 parts by weight of the treated fused spherical silica-aluminum hydroxide and 1000 parts by weight of methanol for 30 minutes with an ultrasonic cleaner, and then dried at 80 ° C. for 1 hour. When the elemental analysis of the carbon element of this processed fused spherical silica-aluminum hydroxide was performed, the fixing rate was 85%.
[0024]
The treated aluminum hydroxide C used in Comparative Example 1 was prepared by stirring 100 parts by weight of aluminum hydroxide C having the properties shown in Table 1 in a supermixer, 0.2 parts by weight of γ-glycidoxypropyltrimethoxysilane, γ -0.3 part by weight of aminopropyltriethoxysilane was sprayed uniformly and stirring was continued for 15 minutes. Then, it heated at 150 degreeC for 3 hours, Then, 10 weight part of processed aluminum hydroxide and 100 weight part of methanol were processed for 30 minutes with the ultrasonic washing machine, Then, it dried at 80 degreeC for 1 hour. When the elemental analysis of the carbon element of this processed aluminum hydroxide was conducted, the adhesion rate was 87%.
[0025]
The treated aluminum hydroxide D used in Comparative Example 2 was prepared by stirring 100 parts by weight of aluminum hydroxide C having the properties shown in Table 1 in a super mixer while adding 0.2 parts by weight of γ-glycidoxypropyltrimethoxysilane, γ -0.3 part by weight of aminopropyltriethoxysilane was sprayed uniformly and stirring was continued for 3 minutes. Thereafter, 10 parts by weight of treated aluminum hydroxide and 100 parts by weight of methanol were treated with an ultrasonic cleaner for 30 minutes and then dried at 80 ° C. for 1 hour. When the elemental analysis of the carbon element of this processed aluminum hydroxide was conducted, the adhesion rate was 23%.
The silane coupling agents used in Comparative Example 3 are γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane.
The treated fused spherical silica used in Comparative Example 4 was prepared by stirring 0.2 parts by weight of fused spherical silica in a supermixer while stirring 0.2 parts by weight of γ-glycidoxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane. .3 parts by weight were sprayed uniformly and stirring was continued for 15 minutes. Subsequently, the mixture was heated at 150 ° C. for 3 hours, treated with 100 parts by weight of the treated fused spherical silica and 1000 parts by weight of methanol for 30 minutes with an ultrasonic cleaner, and then dried at 80 ° C. for 1 hour. When the elemental analysis of the carbon element of this processed fused spherical silica was performed, the fixing rate was 72%. The properties of aluminum hydroxide A used in Comparative Examples 3 and 4 are those shown in Table 1.
[0026]
[Table 1]

[0027]
[Table 2]

[0028]
【The invention's effect】
According to the present invention, there is obtained an epoxy resin composition for encapsulating a semiconductor which does not contain a halogen-based flame retardant and an antimony compound, and has excellent properties such as flowability and curability, and excellent strength at heat. The conventional semiconductor device has excellent solder crack resistance.

Claims (4)

(A) epoxy resin, (B) phenol resin, (C) curing accelerator, (D) inorganic filler, and (E) water having a roundness of 0.4 to 1.0 previously treated with a silane coupling agent An epoxy resin composition for semiconductor encapsulation, comprising aluminum oxide. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the silane coupling agent is at least one selected from the general formulas (1) to (3).

(R is an alkyl group having 1 to 4 carbon atoms) The semiconductor encapsulation according to claim 1 or 2, wherein the adhesion rate of the silane coupling agent on the surface of aluminum hydroxide having a roundness of 0.4 to 1.0 that has been treated with a silane coupling agent in advance is 70 to 100%. Epoxy resin composition. A semiconductor device comprising a semiconductor element sealed with the epoxy resin composition according to claim 1.