JP3585615B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

Description

（ただし、式（１）中のＲは、水素、ハロゲン、アルキル基の中から選択される同一もしくは異なる原子または基）
【化４】

（ただし、式（２）中、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４は、芳香環もしくは複素環を有する１価の有機基又は１価の脂肪族基であり、それらは互いに同一であっても異なっていてもよい。また、Ｙ_１、Ｙ_２、Ｙ_３及びＹ_４は芳香環もしくは複素環を有する１価の有機基または１価の脂肪族基であって、それらのうち少なくとも１個は、分子外に放出し得るプロトンを少なくとも１個有するプロトン供与体がプロトンを１個放出してなる基であり、それらは互いに同一であっても異なっていてもよい。）
好ましくは、式（２）で示される硬化促進剤のプロトン供与体が、１分子内に少なくとも１個のカルボキシル基を有する芳香族カルボン酸である半導体封止用エポキシ樹脂組成物である。
軟化点はＪＩＳ Ｋ ２２０７に準じ、ボーリング法で昇温速度３±０．５℃で測定する。エポキシ樹脂の軟化点が５０℃未満だと取扱いが難しくて使用しづらく、９０℃を越えると無機充填材量を必要量配合することができない。同様にフェノール樹脂も軟化点が５５℃未満だと取扱いが難しく使用しづらく、１３０℃を越えると無機充填材量を必要量配合することができない。
【０００６】
【発明の実施の形態】
以下、各項目に関し詳細に説明する。
本発明で用いられる式（１）のエポキシ樹脂は、ジシクロペンタジエンとフェノール類とを付加反応により重合させたフェノール樹脂をグリシジルエーテル化することによって得られるエポキシ樹脂で、従来のオルソクレゾールノボラックエポキシ樹脂に比較し、ガラス転移温度を越えた高温時の弾性率が低く、リードフレーム等の金属類との接着性に優れる。従って、表面実装の半田付け時における熱ストレスを低減させることができ、耐半田クラック性に優れるエポキシ樹脂組成物を得ることができる。耐半田クラック性の効果を引き出すためには、式（１）で示されるエポキシ樹脂を総エポキシ樹脂量に対して３０重量％以上、好ましくは５０重量％以上使用することが望ましい。３０重量％未満だと高温時の低弾性化及び高接着性が得られず耐半田クラック性が不十分である。また全組成物中の無機充填材量を７０〜９２重量％とするためには、軟化点の低いエポキシ樹脂を使用することが好ましい。更に式（１）中のＲは水素原子が好ましい。
【０００７】
式（１）で示されるエポキシ樹脂以外に他のエポキシ樹脂と併用する場合、使用するエポキシ樹脂は、エポキシ基を有するモノマー、オリゴマー、ポリマー全般を指し、例えば、ビフェニル型エポキシ化合物、ビスフェノール型エポキシ化合物、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化合物、アルキル変性トリフェノールメタン型エポキシ化合物及びトリアジン核含有エポキシ樹脂等が挙げられる。
【０００８】
本発明に用いられるフェノール樹脂硬化剤は、上記のエポキシ樹脂と硬化反応を行い架橋構造を形成することができる少なくとも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、ポリマー全般を指し、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、パラキシリレン変性フェノール樹脂、メタキシリレン・パラキシリレン変性フェノール樹脂等のフェノ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、これらは単独でも混合して使用しても差し支えない。軟化点、水酸基当量等も特に規定するものではないが、樹脂中の塩素含有量は極力低い方が長期信頼性の点から好ましい。
全組成物中の無機充填材量を７０〜９２重量％とするためには、エポキシ樹脂と同様、軟化点の低い硬化剤を使用することが望ましい。
【０００９】
本発明に用いられる硬化促進剤は、下記式（２）で示されるホスホニウムボレートからなる。
【化５】

ただし、式（２）において、ホスホニウム基のＲ_１、Ｒ_２、Ｒ_３及びＲ_４は、芳香環もしくは複素環を有する１価の有機基又は１価の脂肪族基であり、それらは互いに同一であっても異なっていてもよい。
【００１０】
このようなホスホニウム基としては、例えば、テトラフェニルホスホニウム基、テトラトリルホスホニウム基、テトラエチルフェニルホスホニウム基、テトラメトキシフェニルホスホニウム基、テトラナフチルホスホニウム基、テトラベンジルホスホニウム基、エチルトリフェニルホスホニウム基、ｎ−ブチルトリフェニルホスホニウム基、２−ヒドロキシエチルトリフェニルホスホニウム基、トリメチルフェニルホスホニウム基、メチルジエチルフェニルホスホニウム基、メチルジアリルフェニルホスホニウム基、テトラ−ｎ−ブチルホスホニウム基等を挙げることができる。式（２）において、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４は、芳香環を有する１価の有機基であることが特に好ましく、また、式（２）で示されるホスホニウムボレートの融点は特に限定されるものではないが、均一分散の点からは２５０℃以下であることが好ましい。特に、テトラフェニルホスホニウム基を有するホスホニウムボレートは、熱硬化性樹脂との相溶性が良好であり、好適に使用することができる。
【００１１】
式（２）において、ボレート基のＹ_１、Ｙ_２、Ｙ_３及びＹ_４は、芳香環もしくは複素環を有する１価の有機基または１価の脂肪族基であって、それらのうち少なくとも１個は、分子外に放出し得るプロトンを少なくとも１個有するプロトン供与体がプロトンを１個放出してなる基であり、Ｙ_１、Ｙ_２、Ｙ_３及びＹ_４は互いに同一であっても異なっていてもよい。このようなボレート基を与えるプロトン供与体としては、例えば、酢酸、トリフルオロ酸、ステアリン酸、安息香酸、１−ナフトエ酸、２−ナフトエ酸、フタル酸、トリメット酸、ピロメリット酸、２，６−ナフタレンジカルボン酸、ポリアクリル酸等のカルボン酸やその無水物の部分開環体、フェノール、１−ナフトール、２−ナフトール、ポリフェノール、イソシアヌル酸、ベンゾトリアゾール、さらにこれらのうち芳香環を有する化合物の芳香環に置換基を有する化合物等を挙げることができるが、好ましくは、安息香酸、１−ナフトエ酸、２−ナフトエ酸、フタル酸、トリメット酸、ピロメリット酸、２，６−ナフタレンジカルボン酸が良好であり、好適に使用できる。
【００１２】
本発明の式（２）で示されるホスホニウムボレートからなる硬化促進剤は、熱硬化性樹脂に配合された場合、常温においては触媒活性を示さないので熱硬化性樹脂の硬化反応が進むことがなく、成形時の高温において触媒活性が発現し、しかもいったん発現すると従来の硬化促進剤よりも強い触媒活性を示して熱硬化性樹脂を高度に硬化させる。
本発明の硬化促進剤は、全エポキシ樹脂組成物に対し０．１０〜１重量％であり、通常適度の高温下、例えば７０〜１５０℃で混合することができる。硬化促進剤が０．１０重量％未満であると加熱成形時において充分な硬化性が得られない恐れがあり、１重量％を越えると、硬化が速すぎて成形時に流動性の低下により充填不良などを生ずる恐れがある。
本発明の硬化促進剤は、単独で使用することができ、あるいは他の硬化促進剤と混合して用いることができる。他の硬化促進剤と混合して使用する場合、本発明の硬化促進剤は、他の硬化促進剤との合計量の４０重量％以上であることが好ましい。本発明の硬化促進剤が４０重量％未満であると、本発明の目的を充分に達成できない恐れがある。本発明の硬化促進剤と混合して使用できる他の硬化促進剤は、例えば、トリフェニルホスフィン、テトラフェニルホスホニウムテトラフェニルボレート、１，８−ジアザビシクロ［５．４．０］ウンデセン−７等を挙げることができる。
【００１３】
本発明で用いられる無機充填材としては、溶融破砕シリカ粉末、溶融球状シリカ粉末、結晶シリカ粉末、２次凝集シリカ粉末、アルミナ等が挙げられ、特に封止樹脂組成物の流動性の向上という観点から、溶融球状シリカ粉末が望ましい。球状シリカ粉末の形状は、流動性改善のために、粒子自体の形状は限りなく真球状であることが望ましく、更に粒度分布がブロードで有ることが望ましい。
又、無機充填材の配合量としては、耐半田クラック性と成形性及び流動性のバランスから全組成物中に７０〜９２重量％が望ましい。無機充填材量が７０重量％未満であると、低吸水率化、低熱膨張化が得られず耐半田クラック性が不十分である。また、無機充填材量が９２重量％を越えると高粘度化により半導体パッケージ内部の金線変形、ダイパッド変形を引き起こす等の不具合を生じる。
【００１４】
本発明の組成物は、エポキシ樹脂、フェノール樹脂硬化剤、硬化促進剤及び無機充填材を必須成分とするがこれ以外に、必要に応じて、カーボンブラック等の着色剤、ブロム化エポキシ樹脂、三酸化アンチモン等の難燃剤、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、シリコーンオイル、ゴム等の低応力成分、カルナバワックス等の離型剤を添加することができる。
本発明のエポキシ樹脂組成物は、エポキシ樹脂、フェノール樹脂硬化剤、硬化促進剤、無機充填材、その他添加剤をミキサー等にて充分に均一混合し、熱ロールまたはニーダー等の混練機にて溶融混練し、冷却後粉砕し成形材料を得ることができる。
【００１５】
【実施例】
以下本発明を実施例にて具体的に説明する。
《実施例１》
下記組成物
・式（３）で示されるエポキシ樹脂 １０．２重量部
（軟化点６５℃、エポキシ当量２５０）
【化６】

（ｎ＝０が１に対し、ｎ＝１が０．４、ｎ＝２が０．２５からなる混合物）
・フエノールノボラック樹脂硬化剤 ２．８重量部
（軟化点６０℃、水酸基当量１０５）
・パラキシレン変性フェノール樹脂 ２．８重量部
（軟化点９５℃、水酸基当量１７５）
【００１６】
・式（４）の硬化促進剤 ０．６重量部
【化７】

・溶融破砕シリカ ４５．０重量部
・溶融球状シリカ ３５．０重量部
・カーボンブラック ０．３重量部
・カルナバワックス ０．３重量部
・γ−グリシドキシプロピルトリメトキシシラン ０．５重量部
・臭素化フェノールノボラック型エポキシ樹脂 ０．５重量部
・三酸化アンチモン ２．０重量部
をミキサーにて常温混合し、１００℃で二軸ロールにて混練し、冷却後粉砕し成形材料とした。得られた成形材料のスパイラルフロー、ゲルタイム、常温保管特性、成形性を検討した。
【００１７】
《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／ｃｍ^２ 、硬化時間２分で測定。
・ゲルタイム：
１７５℃に加熱した熱板上で封止樹脂組成物を溶融後、へらで練りながら硬化するまでの時間を測定。
・ショア硬度：
ショアＤ硬度計を用い、金型温度１７５℃、硬化時間２分で測定。
・常温保管性：
樹脂組成物を２５℃にて保管した後、スパイラルフローを測定。初期フロー長さを１００％としたときのフロー残存率が９０％になるまでの日数で示す。
【００１８】
《実施例２〜３》
表１の処方に従って配合し、実施例１と同様にして成形材料を得、同様に評価した。これらの評価結果を表１に示す。
《比較例１〜３》
表１の処方に従って配合し、実施例１と同様にして成形材料を得、同様に評価した。実施例１以外で使用するその他の原料は、エポキシ樹脂はオルソクレゾールノボラック型エポキシ樹脂（軟化点６０℃、エポキシ当量２００）、硬化促進剤はトリフェニルホスフィン及びテトラフェニルホスフォニウム・テトラフェニルボレートである。これらの評価結果を表１に示す。
【００１９】

【００２０】

【００２１】
【発明の効果】
本発明による樹脂組成物は、常温保存性及び流動性に優れ、成形時の硬化特性を大幅に改善でき、かつ耐半田クラック性に優れ、生産性を大きく向上させることができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an epoxy resin composition for semiconductor encapsulation, which is compatible with insertion mounting and surface mounting, and has excellent room temperature storage characteristics and moldability of the resin composition.
[0002]
[Prior art]
Epoxy resin-based semiconductor encapsulation resins have been developed and manufactured to protect the body of diodes, transistors, ICs, and the like from mechanical and chemical effects. Items required for this resin composition are changing depending on the type of element, the structure of the package, and the environment in which it is used. In particular, for ICs, an epoxy resin composition containing an inorganic filler such as an ortho-cresol novolak type epoxy resin, a phenol novolak resin, fused silica, and crystalline silica having excellent heat resistance and moisture resistance is used.
However, in recent years, chips have become larger and larger as ICs become more highly integrated, and packages have changed from conventional insertion type DIP types to small and thin QFPs, SOPs, SOJs, TSOPs, TQFPs, and PLCCs, which are surface-mounted. ing. A large chip is enclosed in a small and thin package, cracks are generated by thermal stress, and problems such as a decrease in moisture resistance due to the cracks have been greatly highlighted. In particular, a sudden exposure to a high temperature of 200 ° C. or more in the soldering process causes a problem that the moisture resistance is deteriorated due to cracking of the package and separation of the resin and the lead frame and between the resin and the chip.
[0003]
As a method of improving the solder crack resistance, a resin composition containing a large amount of an inorganic filler has been developed.As a method of compounding a large amount of the inorganic filler, a particle size distribution and shape selection of the inorganic filler, epoxy There is a reduction in the viscosity of the resin and the hardener resin. However, when the molecular weight of the resin is reduced to reduce the viscosity of the resin, the molecules tend to move, and the cross-linking reaction proceeds rapidly in the initial stage of the reaction. And the reaction is likely to occur at room temperature for the same reason, and the room temperature storage stability of the resin composition is reduced. Furthermore, a resin having a low molecular weight has a high initial reactivity, but at the final stage of the reaction, conversely, the crosslinking density is not sufficiently increased, and the sealing resin composition is not sufficiently cured.
Conventionally used curing accelerators include 2-methylimidazole, 1,8-diazabicyclo [5.4.0] undecene-7, triphenylphosphine and the like. Epoxy resin compositions using these have poor storage stability at room temperature because they show a curing acceleration effect even at low temperatures. Therefore, when they are stored at room temperature, poor fluidity during molding may cause poor filling or IC chips. Problems such as breakage of the gold wire and occurrence of conduction failure occur. For this reason, in order to maintain the initial fluidity of the epoxy resin composition, refrigerated storage and refrigerated transport must be performed, and storage and transport are currently costly.
[0004]
[Problems to be solved by the invention]
The present invention has been made as a result of various studies in order to solve these problems. By using the epoxy resin represented by the formula (1) as the epoxy resin, the adhesiveness between the lead frame and the semiconductor chip can be improved. In addition, by reducing the water absorption of the molded product, the soldering stress of the semiconductor package at the time of mounting on the substrate is remarkably improved, and by using the curing accelerator of the formula (2), the fluidity is excellent and the curability at the time of molding is greatly improved. It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation, wherein the epoxy resin composition contains 70 to 92% by weight of an inorganic filler capable of improving the room-temperature storage characteristics of the resin composition at the same time as the improvement.
[0005]
[Means for Solving the Problems]
The present invention relates to an epoxy resin having a softening point of 50 to 90 ° C represented by the following formula (1), a phenol resin curing agent having a softening point of 55 to 130 ° C, a curing accelerator represented by the following formula (2), and an inorganic filler And an epoxy resin composition for encapsulating a semiconductor, comprising 70 to 92% by weight of the inorganic filler in the entire composition.
Embedded image

(However, R in the formula (1) is the same or different atom or group selected from hydrogen, halogen, and alkyl group)
Embedded image

(However, in the formula (2), R ₁ , R ₂ , R ₃ and R ₄ are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and they are the same as each other. Y ₁ , Y ₂ , Y ₃ and Y ₄ are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and at least one of them. Is a group in which a proton donor having at least one proton that can be released outside the molecule releases one proton, and they may be the same or different from each other.)
Preferably, the epoxy resin composition for semiconductor encapsulation wherein the proton donor of the curing accelerator represented by the formula (2) is an aromatic carboxylic acid having at least one carboxyl group in one molecule.
The softening point is measured at a rate of temperature rise of 3 ± 0.5 ° C. by a boring method according to JIS K 2207. If the softening point of the epoxy resin is less than 50 ° C., it is difficult to handle and it is difficult to use, and if it exceeds 90 ° C., the required amount of the inorganic filler cannot be blended. Similarly, if the softening point of the phenolic resin is less than 55 ° C., it is difficult to handle, and if it exceeds 130 ° C., the required amount of the inorganic filler cannot be blended.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, each item will be described in detail.
The epoxy resin of the formula (1) used in the present invention is an epoxy resin obtained by glycidyl etherification of a phenol resin obtained by polymerizing dicyclopentadiene and phenol by an addition reaction, and is a conventional orthocresol novolak epoxy resin. As compared with the above, the elastic modulus at a high temperature exceeding the glass transition temperature is low, and the adhesiveness to metals such as a lead frame is excellent. Therefore, it is possible to reduce the thermal stress at the time of surface mounting soldering, and to obtain an epoxy resin composition having excellent solder crack resistance. In order to bring out the effect of solder crack resistance, it is desirable to use the epoxy resin represented by the formula (1) in an amount of 30% by weight or more, preferably 50% by weight or more based on the total epoxy resin amount. If it is less than 30% by weight, low elasticity and high adhesion at high temperatures cannot be obtained, and solder crack resistance is insufficient. In order to make the amount of the inorganic filler in the entire composition 70 to 92% by weight, it is preferable to use an epoxy resin having a low softening point. Further, R in the formula (1) is preferably a hydrogen atom.
[0007]
When used in combination with another epoxy resin other than the epoxy resin represented by the formula (1), the epoxy resin used generally refers to monomers, oligomers, and polymers having an epoxy group, such as a biphenyl type epoxy compound and a bisphenol type epoxy compound. Phenol novolak type epoxy resin, cresol novolak type epoxy resin, triphenolmethane type epoxy compound, alkyl-modified triphenolmethane type epoxy compound, and epoxy resin containing triazine nucleus.
[0008]
The phenolic resin curing agent used in the present invention refers to all monomers, oligomers and polymers having at least two or more phenolic hydroxyl groups capable of forming a crosslinked structure by performing a curing reaction with the epoxy resin, and is particularly limited. Although not a thing, for example, phenol novolak resin, cresol novolak resin, phenol aralkyl resin such as para-xylylene-modified phenol resin, meta-xylylene / para-xylylene-modified phenol resin, terpene-modified phenol resin, dicyclopentadiene-modified phenol resin, etc. However, they can be mixed and used. The softening point, hydroxyl group equivalent and the like are not particularly specified, but the chlorine content in the resin is preferably as low as possible from the viewpoint of long-term reliability.
In order to make the amount of the inorganic filler in the entire composition 70 to 92% by weight, it is desirable to use a curing agent having a low softening point, like the epoxy resin.
[0009]
The curing accelerator used in the present invention comprises a phosphonium borate represented by the following formula (2).
Embedded image

However, in the formula (2), R ₁ , R ₂ , R ₃ and R ₄ of the phosphonium group are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and they are the same as each other. Or different.
[0010]
Examples of such a phosphonium group include, for example, a tetraphenylphosphonium group, a tetratolylphosphonium group, a tetraethylphenylphosphonium group, a tetramethoxyphenylphosphonium group, a tetranaphthylphosphonium group, a tetrabenzylphosphonium group, an ethyltriphenylphosphonium group, and n-butyl. Examples include a triphenylphosphonium group, a 2-hydroxyethyltriphenylphosphonium group, a trimethylphenylphosphonium group, a methyldiethylphenylphosphonium group, a methyldiallylphenylphosphonium group, and a tetra-n-butylphosphonium group. In the formula (2), R ₁ , R ₂ , R ₃ and R ₄ are particularly preferably a monovalent organic group having an aromatic ring, and the melting point of the phosphonium borate represented by the formula (2) is particularly preferable. Although not limited, the temperature is preferably 250 ° C. or lower from the viewpoint of uniform dispersion. In particular, a phosphonium borate having a tetraphenylphosphonium group has good compatibility with a thermosetting resin and can be suitably used.
[0011]
In the formula (2), Y ₁ , Y ₂ , Y ₃ and Y ₄ of the borate group are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and at least one of them. Is a group in which a proton donor having at least one proton capable of being released outside the molecule releases one proton, and Y ₁ , Y ₂ , Y ₃ and Y ₄ are different even if they are the same as each other May be. Examples of such a proton donor that provides a borate group include acetic acid, trifluoroacid, stearic acid, benzoic acid, 1-naphthoic acid, 2-naphthoic acid, phthalic acid, trimetic acid, pyromellitic acid, and 2,6. -Naphthalenedicarboxylic acid, partially ring-opened forms of carboxylic acids such as polyacrylic acid and anhydrides thereof, phenol, 1-naphthol, 2-naphthol, polyphenol, isocyanuric acid, benzotriazole, and compounds having an aromatic ring among these. Examples of the compound having a substituent on an aromatic ring include, for example, benzoic acid, 1-naphthoic acid, 2-naphthoic acid, phthalic acid, trimetic acid, pyromellitic acid, and 2,6-naphthalenedicarboxylic acid. Good and suitable for use.
[0012]
When the curing accelerator comprising the phosphonium borate represented by the formula (2) of the present invention is incorporated into a thermosetting resin, it does not exhibit catalytic activity at room temperature, so that the curing reaction of the thermosetting resin does not proceed. The catalyst activity is exhibited at a high temperature during molding, and once exhibited, the catalyst exhibits a stronger catalytic activity than conventional curing accelerators, and highly cures the thermosetting resin.
The curing accelerator of the present invention is 0.10 to 1% by weight based on the entire epoxy resin composition, and can be usually mixed at a moderately high temperature, for example, at 70 to 150 ° C. If the amount of the curing accelerator is less than 0.10% by weight, sufficient curability may not be obtained during heat molding. If the amount exceeds 1% by weight, curing is too fast and the fluidity decreases during molding, resulting in poor filling. Etc. may occur.
The curing accelerator of the present invention can be used alone, or can be used as a mixture with another curing accelerator. When used in combination with another curing accelerator, the curing accelerator of the present invention preferably accounts for 40% by weight or more of the total amount with the other curing accelerator. If the amount of the curing accelerator of the present invention is less than 40% by weight, the object of the present invention may not be sufficiently achieved. Other curing accelerators that can be used in combination with the curing accelerator of the present invention include, for example, triphenylphosphine, tetraphenylphosphonium tetraphenylborate, 1,8-diazabicyclo [5.4.0] undecene-7, and the like. be able to.
[0013]
Examples of the inorganic filler used in the present invention include a melt-crushed silica powder, a fused spherical silica powder, a crystalline silica powder, a secondary aggregated silica powder, alumina and the like, particularly from the viewpoint of improving the fluidity of the sealing resin composition. Therefore, a fused spherical silica powder is desirable. Regarding the shape of the spherical silica powder, in order to improve the fluidity, it is desirable that the shape of the particles themselves be infinitely spherical and that the particle size distribution be broad.
The amount of the inorganic filler is preferably 70 to 92% by weight in the whole composition in view of the balance between solder crack resistance, moldability and fluidity. When the amount of the inorganic filler is less than 70% by weight, low water absorption and low thermal expansion cannot be obtained, and solder crack resistance is insufficient. On the other hand, if the amount of the inorganic filler exceeds 92% by weight, problems such as causing gold wire deformation and die pad deformation inside the semiconductor package due to high viscosity are caused.
[0014]
The composition of the present invention contains an epoxy resin, a phenol resin curing agent, a curing accelerator, and an inorganic filler as essential components. In addition to this, if necessary, a coloring agent such as carbon black, a brominated epoxy resin, Flame retardants such as antimony oxide, coupling agents such as γ-glycidoxypropyltrimethoxysilane, low-stress components such as silicone oil and rubber, and release agents such as carnauba wax can be added.
The epoxy resin composition of the present invention is obtained by sufficiently uniformly mixing an epoxy resin, a phenolic resin curing agent, a curing accelerator, an inorganic filler, and other additives with a mixer or the like, and melting the mixture with a kneader such as a hot roll or a kneader. After kneading, cooling and pulverizing, a molding material can be obtained.
[0015]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples.
<< Example 1 >>
10.2 parts by weight of an epoxy resin represented by the following composition and formula (3) (softening point: 65 ° C., epoxy equivalent: 250)
Embedded image

(A mixture of 0.4 for n = 1 and 0.25 for n = 2 for 1 for n = 0)
・ Phenol novolak resin curing agent 2.8 parts by weight (softening point 60 ° C., hydroxyl equivalent 105)
2.8 parts by weight of para-xylene-modified phenol resin (softening point: 95 ° C., hydroxyl equivalent: 175)
[0016]
・ 0.6 parts by weight of a curing accelerator of the formula (4)

45.0 parts by weight of fused silica, 35.0 parts by weight of fused spherical silica, 0.3 parts by weight of carbon black, 0.3 parts by weight of carnauba wax, 0.5 parts by weight of γ-glycidoxypropyltrimethoxysilane. 0.5 part by weight of a brominated phenol novolak type epoxy resin and 2.0 parts by weight of antimony trioxide were mixed at room temperature with a mixer, kneaded at 100 ° C. with a biaxial roll, cooled and pulverized to obtain a molding material. The spiral flow, gel time, room temperature storage characteristics, and moldability of the obtained molding material were examined.
[0017]
"Evaluation method"
・ Spiral flow:
Using a mold for spiral flow measurement according to EMMI-1-66, measurement was performed at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 2 minutes.
・ Gel time:
After the sealing resin composition was melted on a hot plate heated to 175 ° C., the time required for curing while kneading with a spatula was measured.
・ Shore hardness:
Measured using a Shore D hardness meter at a mold temperature of 175 ° C and a curing time of 2 minutes.
-Room temperature storage:
After storing the resin composition at 25 ° C., the spiral flow was measured. The number of days until the residual flow rate becomes 90% when the initial flow length is set to 100% is shown.
[0018]
<< Examples 2-3 >>
It was blended according to the formulation in Table 1, and a molding material was obtained in the same manner as in Example 1 and evaluated in the same manner. Table 1 shows the evaluation results.
<< Comparative Examples 1-3 >>
It was blended according to the formulation in Table 1, and a molding material was obtained in the same manner as in Example 1 and evaluated in the same manner. Other raw materials used in addition to Example 1 were ortho-cresol novolak type epoxy resin (softening point: 60 ° C., epoxy equivalent: 200) as epoxy resin, and triphenylphosphine and tetraphenylphosphonium tetraphenylborate as curing accelerators. is there. Table 1 shows the evaluation results.
[0019]

[0020]

[0021]
【The invention's effect】
ADVANTAGE OF THE INVENTION The resin composition by this invention is excellent in room temperature preservability and fluidity, can largely improve the hardening characteristic at the time of shaping | molding, is excellent in solder crack resistance, and can greatly improve productivity.

Claims (2)

An epoxy resin having a softening point of 50 to 90 ° C. represented by the following formula (1), a phenol resin curing agent having a softening point of 55 to 130 ° C., a curing accelerator represented by the following formula (2), and an inorganic filler are essential components. And an epoxy resin composition for semiconductor encapsulation, comprising 70 to 92% by weight of the inorganic filler in the whole composition.

(However, R in the formula (1) is the same or different atom or group selected from hydrogen, halogen, and alkyl group)

(However, in the formula (2), R ₁ , R ₂ , R ₃ and R ₄ are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and they are the same as each other. Y ₁ , Y ₂ , Y ₃ and Y ₄ are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and at least one of them. Is a group in which a proton donor having at least one proton that can be released outside the molecule releases one proton, and they may be the same or different from each other.) The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the proton donor of the curing accelerator represented by the formula (2) is an aromatic carboxylic acid having at least one carboxyl group in one molecule.