JP3802714B2 - Semiconductor sealing resin composition and semiconductor device using the same - Google Patents

Description

【００２４】
上記一般式（２）中のＲ₁ 〜Ｒ₄ で表される、−Ｈ（水素）または炭素数１〜５のアルキル基のうち、上記アルキル基としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基等の直鎖状または分岐状の低級アルキル基があげられ、特にメチル基が好ましく、上記Ｒ₁ 〜Ｒ₄ は互いに同一であっても異なっていてもよい。なかでも、低吸湿性および反応性という観点から、上記Ｒ₁ 〜Ｒ₄ が全てメチル基である下記の式（３）で表される構造のビフェニル型エポキシ樹脂を用いることが特に好適である。
【００２５】
【化４】

【００２６】
上記エポキシ樹脂（Ａ成分）とともに用いられるフェノール樹脂（Ｂ成分）は、上記エポキシ樹脂の硬化剤として作用するものであって、特に限定するものではなく従来公知のものが用いられる。例えば、フェノールノボラック、クレゾールノボラック、ビスフェノールＡ型ノボラック、ナフトールノボラックおよびフェノールアラルキル樹脂等があげられる。なかでも、上記エポキシ樹脂（Ａ成分）としてビフェニル型エポキシ樹脂を用いる場合には、フェノール樹脂として下記の一般式（４）で表されるフェノールアラルキル樹脂を用いることが好ましい。
【００２７】
【化５】

【００２８】
そして、上記エポキシ樹脂（Ａ成分）と上記フェノール樹脂（Ｂ成分）の配合割合は、上記エポキシ樹脂中のエポキシ基１当量当たり、フェノール樹脂中の水酸基が０．７〜１．３当量となるように設定することが好ましく、なかでも０．９〜１．１当量となるよう設定することが特に好ましい。
【００２９】
そして、上記ＡおよびＢ成分とともに用いられる多面体形状の複合化金属水酸化物（Ｃ成分）は、下記の一般式（１）で表され、かつ結晶形状が多面体形状を有するものである。
【００３０】
【化６】
ｍ（Ｍ_a Ｏ_b ）・ｎ（Ｑ_d Ｏ_e ）・ｃＨ₂ Ｏ …（１）
〔上記式（１）において、ＭとＱは互いに異なる金属元素であり、Ｑは、周期律表のIVａ，Ｖａ，VIａ， VIIａ，VIII，Ｉｂ，IIｂから選ばれた族に属する金属元素である。また、ｍ，ｎ，ａ，ｂ，ｃ，ｄ，ｅは正数であって、互いに同一の値であってもよいし、異なる値であってもよい。〕
【００３１】
上記一般式（１）で表される複合化金属水酸化物に関して、式（１）中の金属元素を示すＭとしては、Ａｌ，Ｍｇ，Ｃａ，Ｎｉ，Ｃｏ，Ｓｎ，Ｚｎ，Ｃｕ，Ｆｅ，Ｔｉ等があげられる。
【００３２】
また、上記一般式（１）で表される複合化金属水酸化物中のもう一つの金属元素を示すＱは、周期律表のIVａ，Ｖａ，VIａ， VIIａ，VIII，Ｉｂ，IIｂから選ばれた族に属する金属である。例えば、Ｆｅ，Ｃｏ，Ｎｉ，Ｐｄ，Ｃｕ，Ｚｎ等があげられ、単独でもしくは２種以上併せて選択される。
【００３３】
このような結晶形状が多面体形状を有する複合化金属水酸化物は、例えば、複合化金属水酸化物の製造工程における各種条件等を制御することにより、縦，横とともに厚み方向（ｃ軸方向）への結晶成長が大きい、所望の多面体形状、例えば、略１２面体，略８面体，略４面体等の形状を有する複合化金属水酸化物を得ることができる。
【００３４】
本発明に用いられる多面体形状の複合化金属水酸化物は、その一例として結晶外形が略８面体の多面体構造を示し、アスペクト比が１〜８程度、好ましくは１〜７、特に好ましくは１〜４に調整されたもので、例えば、式（１）中の、Ｍ＝Ｍｇ，Ｑ＝Ｚｎの場合について述べると、つぎのようにして作製することができる。すなわち、まず、水酸化マグネシウム水溶液に硝酸亜鉛化合物を添加し、原料となる部分複合化金属水酸化物を作製する。ついで、この原料を、８００〜１５００℃の範囲で、より好ましくは１０００〜１３００℃の範囲で焼成することにより、複合化金属酸化物を作製する。この複合化金属酸化物は、ｍ（ＭｇＯ）・ｎ（ＺｎＯ）の組成で示されるが、さらにカルボン酸、カルボン酸の金属塩、無機酸および無機酸の金属塩からなる群から選ばれた少なくとも一種を上記複合化金属酸化物に対して約０．１〜６ｍｏｌ％共存する水媒体中の系で強攪拌しながら４０℃以上の温度で水和反応させることにより、ｍ（ＭｇＯ）・ｎ（ＺｎＯ）・ｃＨ₂ Ｏで示される、本発明の多面体形状を有する複合化金属水酸化物を作製することができる。
【００３５】
上記製法において、原料としては、上述した方法で得られる部分複合化金属水酸化物だけでなく、例えば、共沈法によって得られる複合化金属水酸化物，水酸化マグネシウムとＺｎの混合物，酸化マグネシウムとＺｎ酸化物の混合物，炭酸マグネシウムとＺｎ炭酸塩との混合物等も用いることができる。また、水和反応時の攪拌は、均一性や分散性の向上、カルボン酸、カルボン酸の金属塩、無機酸および無機酸の金属塩からなる群から選ばれた少なくとも一種との接触効率向上等のため、強攪拌が好ましく、さらに強力な高剪断攪拌であればなお好ましい。このような攪拌は、例えば、回転羽根式の攪拌機において、回転羽根の周速を５ｍ／ｓ以上として行うのが好ましい。
【００３６】
上記カルボン酸としては、特に限定されるものではないが、好ましくはモノカルボン酸、オキシカルボン酸（オキシ酸）等があげられる。上記モノカルボン酸としては、例えば、ギ酸、酢酸、プロピオン酸、酪酸、吉草酸、カプロン酸、アクリル酸、クロトン酸等があげられ、上記オキシカルボン酸（オキシ酸）としては、例えば、グリコール酸、乳酸、ヒドロアクリル酸、α−オキシ酪酸、グリセリン酸、サリチル酸、安息香酸、没食子酸等があげられる。また、上記カルボン酸の金属塩としては、特に限定されるものではないが、好ましくは酢酸マグネシウム、酢酸亜鉛等があげられる。そして、上記無機酸としては、特に限定されるものではないが、好ましくは硝酸、塩酸等があげられる。また、上記無機酸の金属塩としては、特に限定されるものではないが、好ましくは硝酸マグネシウム、硝酸亜鉛等があげられる。
【００３７】
上記多面体形状を有する複合化金属水酸化物の具体的な代表例としては、ｓＭｇＯ・（１−ｓ）ＮｉＯ・ｃＨ₂ Ｏ〔０＜ｓ＜１、０＜ｃ≦１〕、ｓＭｇＯ・（１−ｓ）ＺｎＯ・ｃＨ₂ Ｏ〔０＜ｓ＜１、０＜ｃ≦１〕、ｓＡｌ₂ Ｏ₃ ・（１−ｓ）Ｆｅ₂ Ｏ₃ ・ｃＨ₂ Ｏ〔０＜ｓ＜１、０＜ｃ≦３〕等があげられる。なかでも、酸化マグネシウム・酸化ニッケルの水和物、酸化マグネシウム・酸化亜鉛の水和物、酸化マグネシウム・酸化銅の水和物が特に好ましく用いられる。
【００３８】
そして、上記多面体形状を有する複合化金属水酸化物（Ｃ成分）としては、下記に示す粒度分布（ｃ１）〜（ｃ３）を有する必要がある。なお、下記に示す粒度分布の測定には、レーザー式粒度測定機を使用する。
（ｃ１）粒径１．３μｍ未満のものが１０〜３５重量％。
（ｃ２）粒径１．３〜２．０μｍ未満のものが５０〜６５重量％。
（ｃ３）粒径２．０μｍ以上のものが１０〜３０重量％。
【００３９】
上記粒度分布において、粒度分布（ｃ１）の粒径１．３μｍ未満のものが１０重量％未満の場合は、難燃性の効果が乏しくなり、逆に３５重量％を超え多くなると、流動性が損なわれる。また、粒度分布（ｃ３）の２．０μｍ以上のものが１０重量％未満では、流動性が低下し、逆に３０重量％を超え多くなると、難燃性の効果が乏しくなる。なお、上記粒度分布（ｃ１）における粒径の通常の下限値は０．１μｍであり、上記粒度分布（ｃ３）における粒径の通常の上限値は１５μｍである。
【００４０】
そして、上記（Ｃ）成分である多面体形状の複合化金属水酸化物では、上記粒度分布（ｃ１）〜（ｃ３）に加えて、その最大粒径が１０μｍ以下であることが好ましい。特に好ましくは最大粒径が６μｍ以下である。すなわち、最大粒径が１０μｍを超えると、難燃性を有するために多くの量を必要とするようになる傾向がみられるからである。
【００４１】
さらに、上記（Ｃ）成分である多面体形状の複合化金属水酸化物の比表面積が２．０〜４．０ｍ² ／ｇの範囲であることが好ましい。なお、上記（Ｃ）成分の比表面積の測定は、ＢＥＴ吸着法により測定される。
【００４２】
また、上記多面体形状を有する複合化金属水酸化物（Ｃ成分）のアスペクト比は、通常１〜８、好ましくは１〜７、特に好ましくは１〜４である。ここでいうアスペクト比とは、複合化金属水酸化物の長径と短径との比で表したものである。すなわち、アスペクト比が８を超えると、この複合化金属水酸化物を含有する樹脂組成物が溶融したときの粘度低下に対する効果が乏しくなる。そして、本発明の半導体封止用樹脂組成物の構成成分として用いられる場合には、一般的に、アスペクト比が１〜４のものが用いられる。
【００４３】
なお、本発明においては、上記（Ｃ）成分である多面体形状の複合化金属水酸化物とともに従来の薄平板形状の複合化金属水酸化物を併用することができる。そして、本発明の半導体封止用樹脂組成物が溶融したときの粘度低下および流動性の効果の発現という点から、用いられる複合化金属水酸化物全体（従来の薄平板形状を含む）中の、多面体形状の複合化金属水酸化物の占める割合を３０〜１００重量％の範囲に設定することが好ましい。すなわち、多面体形状の複合化金属水酸化物の占める割合が３０重量％未満では樹脂組成物の粘度低下の効果および流動性の向上効果が乏しくなる。
【００４４】
上記多面体形状を有する複合化金属水酸化物（Ｃ成分）を含む複合化金属水酸化物の含有量は、樹脂組成物全体の１〜３０重量％、特には３〜２５重量％の範囲に設定することが好ましい。すなわち、上記複合化金属水酸化物が１重量％未満では、赤燐系難燃剤と併用してもその併用による難燃効果は不充分であることから赤燐系難燃剤を多量に用いる必要が生じ、その結果、耐湿性の低下を引き起こす傾向がみられる。また、３０重量％を超えると、流動性が低下し、ワイヤー流れ等の不良を引き起こす傾向がみられるからである。
【００４５】
上記Ａ〜Ｃ成分とともに用いられる赤燐系難燃剤（Ｄ成分）は、赤燐単独からなるものを含むが、この赤燐単独のものは酸化され易く、また不安定なために取り扱いに難点がある。このため、金属水酸化物およびフェノール樹脂の少なくとも一方で赤燐表面を予め被覆したものを用いることが好ましい。上記被覆材料となる金属水酸化物としては、例えば、水酸化マグネシウム、水酸化アルミニウム等があげられる。また、フェノール樹脂としては、特に限定するものではなく従来公知の各種フェノール樹脂があげられる。このように被覆された赤燐系難燃剤における赤燐の含有量は４５〜９５重量％であることが好ましく、特に好ましくは７０〜９５重量％である。すなわち、赤燐の含有量が４５重量％未満ではこの赤燐系難燃剤そのものを多量に添加しなければ目的とする難燃性を得ることが困難となり、９５重量％を超えるとその被覆効果が低下して、安定性および純度の点で問題が生じる傾向がみられるからである。
【００４６】
さらに、上記赤燐系難燃剤では、レーザー式粒度測定機による平均粒径が５〜７０μｍの範囲のものを用いることが好ましく、より好ましくは１０〜４５μｍである。すなわち、上記赤燐系難燃剤の平均粒径が７０μｍを超えて大きくなると、赤燐系難燃剤の分散性が低下する傾向がみられ、５μｍ未満では流動性の低下を引き起こす傾向がみられるからである。
【００４７】
そして、上記赤燐系難燃剤（Ｄ成分）の含有量は、樹脂組成物全体中の０．１〜２重量％の範囲に設定することが好ましく、特に好ましくは０．１〜１．０重量％である。すなわち、０．１重量％未満では、目的とする難燃性を得るためには相対的に前記複合化金属水酸化物（Ｃ成分）の添加量が増大して流動性の低下を引き起こす傾向がみられ、２重量％を超えると燐酸等の不純物が増加して耐湿性の低下を引き起こすと同時に多量に添加すると難燃性を示さなくなる傾向がみられるからである。
【００４８】
そして、本発明の半導体封止用樹脂組成物には、上記Ａ〜Ｄ成分、および場合により、従来の薄平板形状の複合化金属水酸化物とともに無機質充填剤を用いることができる。上記無機質充填剤としては、特に限定するものではなく従来公知の各種充填剤があげら、例えば、石英ガラス粉末、タルク、シリカ粉末、アルミナ粉末、窒化アルミニウム粉末、窒化珪素粉末等があげられる。これらは単独でもしくは２種以上併せて用いられる。そして、上記無機質充填剤として、得られる硬化物の線膨張係数を低減できるという点からシリカ粉末を用いることが好ましい。なかでも、シリカ粉末として溶融シリカ粉末、とりわけ球状溶融シリカ粉末を用いることが樹脂組成物の良好な流動性という点から特に好ましい。また、上記無機質充填剤において、その平均粒径が１０〜７０μｍの範囲であることが好ましく、より好ましくは１０〜５０μｍである。すなわち、先に述べたように、複合化金属水酸化物が前記粒度分布（ｃ１）〜（ｃ３）を有するとともに、無機質充填剤の平均粒径が上記範囲内であると、樹脂組成物の良好な流動性が得られる。また、上記シリカ粉末としては、場合によりシリカ粉末を摩砕処理してなる摩砕シリカ粉末を用いることもできる。
【００４９】
上記無機質充填剤の含有量は、半導体封止用樹脂組成物全体の６０〜９５重量％となるよう設定することが好ましい。
【００５０】
なお、本発明に係る半導体封止用樹脂組成物には、上記Ａ〜Ｄ成分および無機質充填剤以外に、硬化促進剤、顔料、離型剤、表面処理剤、可撓性付与剤等を必要に応じて適宜に添加することができる。
【００５１】
上記硬化促進剤としては、特に限定するものではなくエポキシ基と水酸基の反応を促進するものであればよく、例えば、１，８−ジアザビシクロ（５，４，０）ウンデセン−７等のジアザビシクロアルケン系化合物、トリエチレンジアミン等の三級アミン類、２−メチルイミダゾール等のイミダゾール類、トリフェニルホスフィン等のリン系化合物等があげられる。これら化合物は単独でもしくは２種以上併せて用いられる。
【００５２】
上記顔料としては、カーボンブラック、酸化チタン等があげられる。また、上記離型剤としては、カルナバワックス、ポリエチレンワックス、パラフィンや脂肪酸エステル、脂肪酸塩等があげられる。
【００５３】
さらに、上記表面処理剤としては、シランカップリング剤等のカップリング剤があげられる。また、上記可撓性付与剤としては、各種シリコーン化合物やブタジエン−アクリロニトリルゴム等があげられる。
【００５４】
また、本発明に係る半導体封止用樹脂組成物では、上記各成分に加えてさらに有機系難燃剤を併用してもよい。上記有機系難燃剤としては、含窒素有機化合物、ホスファゼン系化合物等があげられるが、特に含窒素有機化合物が好ましく用いられる。
【００５５】
上記含窒素有機化合物としては、例えば、メラミン誘導体、シアヌレート誘導体、イソシアヌレート誘導体等の複素環骨格を有する化合物があげられる。これら有機系難燃剤は単独でもしくは２種以上併せて用いられる。
【００５６】
上記有機系難燃剤は、前記複合化金属水酸化物と予め機械的に混合した後配合してもよいし、有機系難燃剤を溶剤に溶解してこれに前記複合化金属水酸化物を添加して脱溶剤し表面処理したものを用いてもよい。
【００５７】
そして、本発明に係る半導体封止用樹脂組成物において、前記Ａ〜Ｄ成分を含む各成分の好適な組み合わせは、つぎのとおりである。すなわち、エポキシ樹脂（Ａ成分）のなかでも、流動性が良好であるという点からビフェニル系エポキシ樹脂が好ましく、またフェノール樹脂（Ｂ成分）としては、その流動性という観点からフェノールアラルキル樹脂が好ましい。そして、赤燐系難燃剤（Ｄ成分）として金属水酸化物およびフェノール樹脂で赤燐粉末表面が被覆されたものを用いることが好ましい。さらに、前記多面体形状の複合化金属水酸化物（Ｃ成分）とともに、無機質充填剤として溶融シリカ粉末を用いることが好ましい。さらに、これら各成分に加えて、上記のような複合化金属水酸化物を用いた場合、離型性が低下する傾向がみられることから、ワックス類を用いることが好ましい。
【００５８】
本発明に係る半導体封止用樹脂組成物は、例えばつぎのようにして製造することができる。すなわち、エポキシ樹脂（Ａ成分）、フェノール樹脂（Ｂ成分）、多面体形状の複合化金属水酸化物（Ｃ成分）、赤燐系難燃剤（Ｄ成分）および無機質充填剤ならびに必要に応じて他の添加剤を所定の割合で配合する。つぎに、この混合物をミキシングロール機等の混練機を用いて加熱状態で溶融混練し、これを室温に冷却する。そして、公知の手段によって粉砕し、必要に応じて打錠するという一連の工程によって目的とする半導体封止用樹脂組成物を製造することができる。
【００５９】
あるいは、上記半導体封止用樹脂組成物の混合物を混練機に導入して溶融状態で混練した後、これを略円柱状の顆粒体に連続的に成形するという一連の工程によって顆粒状の半導体封止用樹脂組成物を製造することができる。
【００６０】
さらに、上記半導体封止用樹脂組成物の混合物をパレット上に受け入れし、これを冷却後、プレス圧延，ロール圧延，あるいは溶媒を混合したものを塗工してシート化する等の方法によりシート状の半導体封止用樹脂組成物を製造することができる。
【００６１】
このようにして得られる半導体封止用樹脂組成物（粉末状，タブレット状，顆粒状等）を用いての半導体素子の封止方法は、特に限定するものではなく、通常のトランスファー成形等の公知の成形方法によって行うことができる。
【００６２】
また、上記シート状の半導体封止用樹脂組成物を用いて、例えば、つぎのようにしてフリップチップ実装による半導体装置を製造することができる。すなわち、上記シート状半導体封止用樹脂組成物を、接合用バンプを備えた半導体素子の電極面側に、あるいは、回路基板のバンプ接合部側に配置し、上記半導体素子と回路基板とをバンプ接合するとともに両者を樹脂封止による接着封止を行うことによりフリップチップ実装して半導体装置を製造することができる。
【００６３】
つぎに、実施例について比較例と併せて説明する。
【００６４】
まず、下記に示す各材料を準備した。
【００６５】
〔エポキシ樹脂〕
４，４′−ビス（２，３−エポキシプロポキシ）−３，３′，５，５′−テトラメチルビフェニル
【００６６】
〔フェノール樹脂〕
前記式（４）で表されるフェノールアラルキル樹脂（軟化点７０℃、水酸基当量１７５）
【００６７】
〔赤燐系難燃剤〕
水酸化マグネシウムおよびフェノール樹脂で赤燐粉末表面が被覆されたもの（赤燐含有率９３重量％、平均粒径３０μｍ：ノーバエクセル、燐化学工業社製）
【００６８】
〔シリカ粉末〕
溶融シリカ粉末（球形、平均粒径２５μｍ、比表面積１．４ｍ² ／ｇ）
【００６９】
〔シランカップリング剤〕
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
【００７０】
〔硬化促進剤〕
トリフェニルホスフィン
【００７１】
〔複合化金属水酸化物〕
つぎに、実施例に先立って下記の表１〜表２に示す多面体形状の複合化金属水酸化物を準備した。なお、多面体形状の複合化金属水酸化物は、先に述べた多面体形状の複合化金属水酸化物の製造方法に準じて作製した。
【００７２】
【表１】

【００７３】
【表２】

【００７４】
【実施例１〜８、比較例１〜３】
ついで、下記の表３〜表４に示す各成分を同表に示す割合で配合し、ミキシングロール機（温度１００℃）で３分間溶融混練を行い、冷却固化した後粉砕して目的とする粉末状エポキシ樹脂組成物を得た。
【００７５】
【表３】

【００７６】
【表４】

【００７７】
このようにして得られた実施例および比較例のエポキシ樹脂組成物を用いて、タブレット化し、成形条件１７５℃×７０ｋｇ／ｃｍ² ×１２０秒間で難燃性用試験片を成形した。また、ＴＯＷＡ自動成形機でＬＱＦＰ−１１４（大きさ：２０ｍｍ×２０ｍｍ×厚み１．４ｍｍ）のパッケージを成形した。これら難燃性用試験片およびパッケージを用いて、難燃性、ワイヤー流れおよび耐湿性を測定評価した。さらに、上記試験片を粉砕した後、１６０℃×２０時間の抽出条件で、燐酸イオンを抽出してそのイオン量をイオンクロマト分析にて測定した。これらの結果を後記の表５〜表６に併せて示す。
【００７８】
〔難燃性〕
ＵＬ９４ Ｖ−０規格の方法に従って難燃性を評価した。なお、合格とは９４−Ｖ０合格を意味する。
【００７９】
〔ワイヤー流れ〕
上記パッケージについて、まず、軟Ｘ線装置により、パッケージ内部の透過画像を観察することにより、金ワイヤーの変形等の不良の発生を測定した。測定した結果、金ワイヤーの変形が確認されたものを×、金ワイヤーの変形が確認されず良好なパッケージが得られたものを○として評価し表示した。
【００８０】
〔耐湿性〕
このようにして作製した半導体装置を用いて、プレッシャークッカー試験（ＰＣＴテスト）をバイアスを印加して行った（条件：１３０℃／８５％ＲＨ、３０Ｖバイアス）。なお、不良モードはリーク不良およびオープン不良を測定し、不良発生までの時間を求めた。
【００８１】
【表５】

【００８２】
【表６】

【００８３】
上記表５および表６の結果から、実施例品は優れた難燃性を示すことはもちろん、ワイヤー流れにおいて問題が生じず、しかも燐酸イオン量も赤燐系難燃剤単独使用の比較例１品と比較して非常に少なく、かつ耐湿性においても良好な結果が得られた。これらのことから、難燃性、流動性および耐湿性の全てにおいて優れていることがわかる。これに対して、比較例１品は赤燐系難燃剤単独の系であり、難燃性および流動性に関しては良好な結果が得られたが、燐酸イオン量が多く耐湿性に劣っている。比較例２品は複合化金属水酸化物単独の系であり、流動性は良好であり、かつ燐酸イオン量が少なく耐湿性に問題は無かったが、難燃性試験が不合格であった。また、比較例３品は、複合化金属水酸化物単独の系であるが、比較例２品よりも複合化金属水酸化物量を多く設定しているため、良好な難燃性を有し、しかも燐酸イオン量が少ないことから耐湿性に関しては問題が無かったが、ワイヤー流れで問題が発生していることから流動性に劣っていることがわかる。
【００８４】
さらに、前記実施例１における、エポキシ樹脂成分を、前記式（２）中のＲ₁ 〜Ｒ₄ が全て水素となるビフェニル型エポキシ樹脂と、前記式（２）中のＲ₁ 〜Ｒ₄ が全てメチル基となるビフェニル型エポキシ樹脂を重量比率で１：１となるように配合した混合系のエポキシ樹脂に代えた。それ以外は実施例１と同様の配合割合に設定してエポキシ樹脂組成物を作製した。このエポキシ樹脂組成物を用いて、前記と同様の測定・評価を行った結果、上記実施例と略同様の良好な結果が得られた。
【００８５】
【発明の効果】
以上のように、本発明は、前記一般式（１）で表され、かつ前記特定の粒度分布を有する多面体形状の複合化金属水酸化物（Ｃ成分）と、赤燐系難燃剤（Ｄ成分）を含有する半導体封止用樹脂組成物である。このように、難燃剤成分として上記多面体形状の複合化金属水酸化物と赤燐系難燃剤とを併用するため、難燃性付与のための上記Ｃ成分およびＤ成分の個々の添加量を抑制することができる。すなわち、片方のみの使用による弊害、例えば、多面体形状の複合化金属水酸化物のみの使用では、難燃性の付与におけるその添加量の多さに起因した流動性の低下、また、赤燐系難燃剤のみの使用では、燐酸等の不純物量が多くこれに起因した耐湿性の低下があげられるが、これら流動性の低下および耐湿性の低下を抑制することができるようになる。さらに、上記多面体形状の複合化金属水酸化物のイオン捕獲効果により、上記燐酸等の不純物が低減されて耐湿性の低下の抑制効果が一層効果的となる。したがって、優れた難燃性とともに、優れた流動性および耐湿信頼性を備えたものが得られる。
【００８６】
そして、上記赤燐系難燃剤（Ｄ成分）として、金属水酸化物およびフェノール樹脂で赤燐を被覆したものを用いると、赤燐の酸化が防止され、また安定性を有するため取り扱い性が良好となる。
【００８７】
また、上記多面体形状の複合化金属水酸化物（Ｃ成分）および赤燐系難燃剤（Ｄ成分）の含有量をそれぞれ特定の範囲に設定することにより、一層優れた流動性および耐湿性が得られる。
【図面の簡単な説明】
【図１】本発明で用いられる多面体形状の複合化金属水酸化物の結晶形状の一例を示す走査型電子顕微鏡写真（倍率５００００倍）である。
【図２】従来の複合化金属水酸化物の結晶形状の一つである六角板状形状を示す斜視図である。
【図３】従来の複合化金属水酸化物の外形を示す説明図であり、（ａ）は平面図、（ｂ）は側面図である。
【図４】本発明の複合化金属水酸化物の外形の一例を示す説明図であり、（ａ）は平面図、（ｂ）は側面図である。
【図５】本発明の複合化金属水酸化物の外形の他の例を示す説明図であり、（ａ）は平面図、（ｂ）は側面図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin composition for encapsulating a semiconductor excellent in flame retardancy, moisture resistance reliability and fluidity, and a semiconductor device using the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, semiconductor elements such as transistors, ICs, and LSIs are encapsulated with an epoxy resin composition to form electronic components. It is essential that this electronic component conforms to UL94 V-0, which is a flame retardant standard. Until now, in order to impart its flame retardant action, antimony compounds such as brominated epoxy resins and antimony oxides are used. The method of adding has been taken.
[0003]
However, recently, from the viewpoint of environmental protection, a flame retardant epoxy resin composition imparted with flame retardancy without using a halogen-based flame retardant and antimony oxide has been required. In response to this requirement, for example, the use of metal hydroxides, boron compounds, red phosphorus compounds and the like as flame retardants has been studied, but many of these compounds have reduced moisture resistance due to a large amount of impurities, It has not been put into practical use due to poor formability due to a decrease in fluidity.
[0004]
[Problems to be solved by the invention]
Among the above compounds, regarding the metal hydroxide, the present applicant has proposed an epoxy resin composition for semiconductor encapsulation using a combination of a metal hydroxide and a metal oxide or a composite metal hydroxide thereof. (Japanese Patent Application No. 7-507466). Further, the present applicant has proposed an epoxy resin composition for semiconductor encapsulation that solves the fluidity problem in the above proposal (Japanese Patent Application No. 9-103646). However, the epoxy resin composition for encapsulating a semiconductor with a high content ratio of the above flame retardant has a good fluidity compared to the conventional one due to the large amount of addition, but still has a slight fluidity. Tended to cause sex decline.
[0005]
In addition, the red phosphorus compound has a flame retarding effect even if it is added in a small amount and is useful, but there is a problem that impurities such as phosphine and phosphoric acid are generated and the reliability is lowered. It was not useful. Therefore, in order to solve such problems, a method using red phosphorus coated with a metal hydroxide and a phenolic resin has been proposed (Japanese Patent Application No. Hei 6-295252). When phosphorus is used, it is necessary to add a large amount, so that a large amount of phosphoric acid is still extracted as an impurity, resulting in a decrease in moisture resistance.
[0006]
The present invention has been made in view of such circumstances, and provides a semiconductor sealing resin composition excellent in flame retardancy, fluidity and moisture resistance reliability, and a highly reliable semiconductor device obtained using the same. With the goal.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention contains the following components (A) to (D)And the component (C) has the particle size distributions (c1) to (c3) shown below.The semiconductor sealing resin composition to be used is a first gist.
[0008]
(A) Epoxy resin.
(B) Phenolic resin.
(C) A polyhedral complex metal hydroxide represented by the following general formula (1).
[Chemical 2]
  m (M_aO_b) ・ N (Q_dO_e) ・ CH₂O ... (1)
[In the above formula (1), M and Q are different metal elements, and Q is a metal element belonging to a group selected from IVa, Va, VIa, VIIa, VIII, Ib, and IIb of the periodic table. . Further, m, n, a, b, c, d, and e are positive numbers, and may be the same value or different values. ]
(D) Red phosphorus flame retardant.
(C1) A particle size of less than 1.3 μm is 10 to 35% by weight.
(C2) The particle size is less than 1.3 to 2.0 μm and 50 to 65% by weight.
(C3) 10 to 30% by weight of particles having a particle size of 2.0 μm or more.
[0009]
Moreover, let the semiconductor device formed by sealing a semiconductor element using the said resin composition for semiconductor sealing be a 2nd summary.
[0010]
The (C) component polyhedral complex metal hydroxide in the resin composition for semiconductor encapsulation of the present invention has a hexagonal plate shape as shown in FIG. In this case, the crystal growth in the thickness direction (c-axis direction) is large in both the vertical and horizontal directions. For example, a plate-like crystal has a thickness direction (c-axis). Direction) and a three-dimensional and spherical shape of the crystal, for example, a complex metal hydroxide having a shape of approximately dodecahedron, approximately octahedron, approximately tetrahedron, etc. It is a mixture of these. Of course, the shape of the polyhedron can be approximated more three-dimensionally and spherically by changing the shape of the polyhedron by pulverization or attrition, in addition to the method of crystal growth. An example of a scanning electron micrograph (magnification 50000 times) showing the crystal shape of this polyhedral complex metal hydroxide is shown in FIG. In this way, in the present invention, by using the polyhedral complex metal hydroxide, a conventional hexagonal plate shape or a plate-like crystal shape such as a scale shape is used. Compared with a thing, the fall of the fluidity | liquidity of a resin composition can be suppressed.
[0011]
The shape of the composite metal hydroxide of the present invention will be described in more detail by taking a substantially octahedral shape as an example. That is, the octahedral shape which is an example of the composite metal hydroxide of the present invention is composed of two parallel upper and lower basal planes and six outer peripheral pyramid surfaces, and the pyramidal surfaces are upwardly inclined and downwardly directed. It has an octahedral shape in which inclined surfaces are alternately arranged.
[0012]
More specifically, for example, a conventional thin crystal plate having a flat crystal shape is a hexagonal crystal structure as shown in FIG. 3, and has a (00 · 1) plane in the Miller-Brabe index as shown in FIG. A hexagonal prism shape whose outer periphery is surrounded by two bottom and top basal planes 10 and six square tube surfaces 11 belonging to the mold surface {10.0}. And since there is little crystal growth to a [001] direction (c-axis direction), it has a thin hexagonal column shape.
[0013]
On the other hand, the composite metal hydroxide of the present invention, as shown in FIG. 4, by controlling the crystal habit at the time of crystal growth, the basal plane 12 of two upper and lower surfaces represented by (00 · 1) plane, The outer periphery is surrounded by six pyramidal surfaces 13 belonging to the mold surface of {10 · 1}. The pyramidal surface 13 has a special crystal habit in which an upward inclined surface 13a such as a (10 • 1) surface and a downward inclined surface 13b such as a (10 • -1) surface are alternately arranged. It has an octahedral shape. Also, the crystal growth in the c-axis direction is larger than the conventional one. 4 shows a shape close to a plate shape, and FIG. 5 shows that the crystal growth further proceeds in the c-axis direction and the crystal habit appears remarkably and becomes isotropic. Thus, the composite metal hydroxide of the present invention includes a shape close to a regular octahedron. That is, the ratio (major axis diameter / thickness) between the major axis diameter of the basal plane and the thickness between the basal planes is preferably 1 to 9. 7 is more preferable as the upper limit of the ratio between the major axis diameter and the thickness. In the Miller-Brabe index, “1 bar” is indicated as “−1”.
[0014]
Thus, it can be seen from the following that the six surfaces surrounding the outer periphery of the composite metal hydroxide of the present invention are pyramidal surfaces belonging to {10 · 1}. That is, when the complex metal hydroxide crystal of the present invention is observed with a scanning electron microscope from the c-axis direction, the crystal exhibits three-fold rotational symmetry with the c-axis as the rotation axis. Further, the calculated value of the inter-surface angle between the (10 · 1) plane and the {10 · 1} mold surface using the measured value of the lattice constant by powder X-ray diffraction is the inter-surface angle in the scanning electron microscope observation. It almost agrees with the measured value.
[0015]
Further, the composite metal hydroxide of the present invention has a half width B of the peak on the (110) plane in powder X-ray diffraction.₁₁₀And the half width B of the peak on the (001) plane₀₀₁Ratio (B₁₁₀/ B₀₀₁) Is 1.4 or more. This also confirms that the crystallinity in the c-axis direction is good and the thickness is growing. That is, in the conventional crystal such as magnesium hydroxide, the crystal in the c-axis direction is not grown, the peak on the (001) plane is broad, and the half width B₀₀₁Also grows. Therefore (B₁₁₀/ B₀₀₁) Becomes smaller. On the other hand, in the composite metal hydroxide of the present invention, since the crystallinity in the c-axis direction is good, the peak of the (001) plane is sharp and thin, and the half-value width B₀₀₁Becomes smaller. Therefore (B₁₁₀/ B₀₀₁) Will increase in value.
[0016]
  That is, the present inventors repeated a series of studies in order to obtain a sealing material excellent in fluidity and moisture resistance reliability as well as flame retardancy. As a result, the aboveHas a specific particle size distributionWhen the composite metal hydroxide having a polyhedral shape and a red phosphorus flame retardant are used in combination, the amount of each added for imparting flame retardancy can be suppressed, and adverse effects due to the use of only one side, for example, the polyhedral shape By using only the complex metal hydroxide, it is possible to suppress the decrease in fluidity due to the addition amount of the flame retardant, and also by using only the red phosphorus flame retardant. The present inventors have found out that the amount of impurities such as phosphoric acid can be reduced to suppress the decrease in moisture resistance. Furthermore, since the complex metal hydroxide having the polyhedral shape has an ion trapping action, it is possible to capture impurities such as phosphoric acid caused by the red phosphorus flame retardant and reduce the amount of impurities in the entire system. Thus, the present inventors have found that a further effect of improving moisture resistance can be obtained, and that the above problems can be solved together with excellent flame retardancy, and the present invention has been achieved.
[0017]
When the red phosphorus flame retardant coated with red phosphorus with a metal hydroxide and a phenol resin is used, oxidation of red phosphorus is prevented and the handleability is improved because of stability.
[0018]
In addition, by setting the polyhedral complex metal hydroxide and red phosphorus flame retardant within a specific range, the fluidity and moisture resistance are further improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail.
[0020]
The resin composition for semiconductor encapsulation of the present invention comprises an epoxy resin (component A), a phenol resin (component B), a polyhedral complex metal hydroxide (component C), and a red phosphorus flame retardant (D Ingredient) is usually obtained in the form of a powder or a tablet obtained by tableting this. Alternatively, after the resin composition is melt-kneaded, it is a sheet-shaped sealing material that is formed into a granular shape that is formed into a substantially cylindrical shape, and further into a sheet shape.
[0021]
The epoxy resin (component A) is not particularly limited, and various conventionally known epoxy resins are used. For example, bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin and the like can be mentioned.
[0022]
And among the said epoxy resins, it is preferable to use a biphenyl type epoxy resin, for example, the biphenyl type epoxy resin represented by following General formula (2) is used.
[0023]
[Chemical Formula 3]

[0024]
R in the general formula (2)₁~ R_Four-H (hydrogen) or an alkyl group having 1 to 5 carbon atoms represented by the following, the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, Examples thereof include linear or branched lower alkyl groups such as sec-butyl group and tert-butyl group, and methyl group is particularly preferable.₁~ R_FourMay be the same as or different from each other. Among these, from the viewpoint of low hygroscopicity and reactivity, the above R₁~ R_FourIt is particularly preferable to use a biphenyl type epoxy resin having a structure represented by the following formula (3) in which all are methyl groups.
[0025]
[Formula 4]

[0026]
The phenol resin (component B) used together with the epoxy resin (component A) acts as a curing agent for the epoxy resin and is not particularly limited, and conventionally known ones are used. Examples thereof include phenol novolak, cresol novolak, bisphenol A type novolak, naphthol novolak, and phenol aralkyl resin. Especially, when using a biphenyl type epoxy resin as said epoxy resin (A component), it is preferable to use the phenol aralkyl resin represented by following General formula (4) as a phenol resin.
[0027]
[Chemical formula 5]

[0028]
And the compounding ratio of the said epoxy resin (A component) and the said phenol resin (B component) is such that the hydroxyl group in a phenol resin will be 0.7-1.3 equivalent per 1 equivalent of epoxy groups in the said epoxy resin. It is preferable to set it to be 0.9 to 1.1 equivalent.
[0029]
The polyhedral complex metal hydroxide (C component) used together with the components A and B is represented by the following general formula (1) and has a polyhedral shape.
[0030]
[Chemical 6]
m (M_aO_b) ・ N (Q_dO_e) ・ CH₂O ... (1)
[In the above formula (1), M and Q are different metal elements, and Q is a metal element belonging to a group selected from IVa, Va, VIa, VIIa, VIII, Ib, and IIb of the periodic table. . Further, m, n, a, b, c, d, and e are positive numbers, and may be the same value or different values. ]
[0031]
Regarding the composite metal hydroxide represented by the general formula (1), M representing the metal element in the formula (1) is Al, Mg, Ca, Ni, Co, Sn, Zn, Cu, Fe, Ti etc.Can be given.
[0032]
Q representing another metal element in the composite metal hydroxide represented by the general formula (1) is selected from IVa, Va, VIa, VIIa, VIII, Ib, and IIb in the periodic table. A metal belonging to the tribe. For example, Fe, Co, Ni, Pd, Cu, Zn and the like can be mentioned, and these are selected singly or in combination of two or more.
[0033]
The composite metal hydroxide having such a polyhedral shape as the crystal shape can be obtained by controlling various conditions in the manufacturing process of the composite metal hydroxide, for example, in the thickness direction (c-axis direction) as well as in the vertical and horizontal directions. A complex metal hydroxide having a desired polyhedral shape, such as a substantially dodecahedron, a substantially octahedron, or a substantially tetrahedron, can be obtained.
[0034]
As an example, the polyhedral complex metal hydroxide used in the present invention has a polyhedral structure having an approximately octahedral crystal shape, and an aspect ratio of about 1 to 8, preferably 1 to 7, particularly preferably 1 to 7. For example, when the case of M = Mg and Q = Zn in the formula (1) is described, it can be manufactured as follows. That is, first, a zinc nitrate compound is added to a magnesium hydroxide aqueous solution to produce a partially complexed metal hydroxide as a raw material. Subsequently, this raw material is fired in the range of 800 to 1500 ° C., more preferably in the range of 1000 to 1300 ° C., so that a composite metal oxide is produced. This composite metal oxide is represented by a composition of m (MgO) · n (ZnO), and at least selected from the group consisting of carboxylic acid, metal salt of carboxylic acid, inorganic acid and metal salt of inorganic acid. One (1) is hydrated at a temperature of 40 ° C. or higher with vigorous stirring in a system in an aqueous medium in which about 0.1 to 6 mol% of the composite metal oxide coexists, whereby m (MgO) · n ( ZnO) · cH₂A composite metal hydroxide having a polyhedral shape of the present invention represented by O can be produced.
[0035]
In the above production method, as a raw material, not only the partially complexed metal hydroxide obtained by the above-described method, but also, for example, a complexed metal hydroxide obtained by a coprecipitation method, a mixture of magnesium hydroxide and Zn, magnesium oxide A mixture of ZnO and Zn oxide, a mixture of magnesium carbonate and Zn carbonate, or the like can also be used. In addition, stirring during the hydration reaction improves uniformity and dispersibility, improves contact efficiency with at least one selected from the group consisting of carboxylic acids, metal salts of carboxylic acids, inorganic acids and metal salts of inorganic acids, etc. Therefore, strong stirring is preferable, and more powerful high shear stirring is more preferable. Such agitation is preferably performed, for example, in a rotary vane type stirrer with a peripheral speed of the rotary vane of 5 m / s or more.
[0036]
Although it does not specifically limit as said carboxylic acid, Preferably monocarboxylic acid, oxycarboxylic acid (oxyacid), etc. are mention | raise | lifted. Examples of the monocarboxylic acid include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, acrylic acid, and crotonic acid. Examples of the oxycarboxylic acid (oxyacid) include glycolic acid, Examples include lactic acid, hydroacrylic acid, α-oxybutyric acid, glyceric acid, salicylic acid, benzoic acid, and gallic acid. In addition, the metal salt of the carboxylic acid is not particularly limited, but preferred examples include magnesium acetate and zinc acetate. The inorganic acid is not particularly limited, but preferred examples include nitric acid and hydrochloric acid. Further, the metal salt of the inorganic acid is not particularly limited, but preferred examples include magnesium nitrate and zinc nitrate.
[0037]
As a concrete representative example of the composite metal hydroxide having the polyhedral shape, sMgO. (1-s) NiO.cH₂O [0 <s <1, 0 <c ≦ 1], sMgO. (1-s) ZnO.cH₂O [0 <s <1, 0 <c ≦ 1], sAl₂O_Three・ (1-s) Fe₂O_Three・ CH₂O [0 <s <1, 0 <c ≦ 3] and the like. Of these, magnesium oxide / nickel oxide hydrate, magnesium oxide / zinc oxide hydrate, and magnesium oxide / copper oxide hydrate are particularly preferably used.
[0038]
  And as a complex metal hydroxide (C component) which has the said polyhedral shape, it has the particle size distribution (c1)-(c3) shown below.There is a need. In addition, a laser particle size measuring machine is used for the measurement of the particle size distribution shown below.
(C1) A particle size of less than 1.3 μm is 10 to 35% by weight.
(C2) The particle size is less than 1.3 to 2.0 μm and 50 to 65% by weight.
(C3) 10 to 30% by weight of particles having a particle size of 2.0 μm or more.
[0039]
  In the above particle size distribution, when the particle size distribution (c1) having a particle size of less than 1.3 μm is less than 10% by weight, the effect of flame retardancy is poor. DamagedTheIn addition, when the particle size distribution (c3) is 2.0 μm or more and less than 10% by weight, the fluidity is decreased.TheThe normal lower limit value of the particle size in the particle size distribution (c1) is 0.1 μm, and the normal upper limit value of the particle size in the particle size distribution (c3) is 15 μm.
[0040]
And in the polyhedral metal complex metal hydroxide which is said (C) component, in addition to said particle size distribution (c1)-(c3), it is preferable that the maximum particle size is 10 micrometers or less. Particularly preferably, the maximum particle size is 6 μm or less. That is, when the maximum particle size exceeds 10 μm, there is a tendency that a large amount is required to have flame retardancy.
[0041]
Furthermore, the specific surface area of the polyhedral polyhedral metal hydroxide which is the component (C) is 2.0 to 4.0 m.²/ G is preferable. The specific surface area of the component (C) is measured by the BET adsorption method.
[0042]
The aspect ratio of the complex metal hydroxide (C component) having the polyhedral shape is usually 1 to 8, preferably 1 to 7, and particularly preferably 1 to 4. The aspect ratio here is expressed by the ratio of the major axis to the minor axis of the composite metal hydroxide. That is, when the aspect ratio exceeds 8, the effect of decreasing the viscosity when the resin composition containing the composite metal hydroxide is melted becomes poor. And when using as a structural component of the resin composition for semiconductor sealing of this invention, a thing with an aspect ratio of 1-4 is generally used.
[0043]
In the present invention, a conventional thin plate-shaped composite metal hydroxide can be used together with the polyhedral composite metal hydroxide which is the component (C). And from the point of the viscosity reduction when the resin composition for semiconductor encapsulation of the present invention melts and the expression of fluidity effect, in the whole composite metal hydroxide used (including the conventional thin plate shape) The proportion of the polyhedral complex metal hydroxide is preferably set in the range of 30 to 100% by weight. That is, if the proportion of the polyhedral metal hydroxide is less than 30% by weight, the effect of decreasing the viscosity and improving the fluidity of the resin composition are poor.
[0044]
The content of the composite metal hydroxide containing the composite metal hydroxide (C component) having the polyhedral shape is set in the range of 1 to 30% by weight, particularly 3 to 25% by weight of the entire resin composition. It is preferable to do. In other words, if the above composite metal hydroxide is less than 1% by weight, even if it is used in combination with a red phosphorus flame retardant, the flame retardant effect of the combined use is insufficient, so it is necessary to use a large amount of red phosphorus flame retardant. As a result, there is a tendency to cause a decrease in moisture resistance. Moreover, when it exceeds 30 weight%, fluidity | liquidity falls and the tendency which causes defects, such as a wire flow, is seen.
[0045]
The red phosphorus flame retardant (D component) used together with the components A to C includes those composed of red phosphorus alone. However, this red phosphorus alone is easy to be oxidized, and it is unstable so that it is difficult to handle. is there. For this reason, it is preferable to use what coat | covered the red phosphorus surface previously at least one of a metal hydroxide and a phenol resin. Examples of the metal hydroxide used as the coating material include magnesium hydroxide and aluminum hydroxide. Moreover, it does not specifically limit as a phenol resin, Conventionally well-known various phenol resins are mention | raise | lifted. The red phosphorus content in the red phosphorus flame retardant thus coated is preferably 45 to 95% by weight, particularly preferably 70 to 95% by weight. That is, if the red phosphorus content is less than 45% by weight, it is difficult to obtain the desired flame retardancy unless the red phosphorus flame retardant itself is added in a large amount. This is because it tends to decrease and cause problems in terms of stability and purity.
[0046]
Furthermore, it is preferable to use the red phosphorus flame retardant having an average particle diameter in the range of 5 to 70 μm, more preferably 10 to 45 μm, using a laser particle size measuring machine. That is, if the average particle size of the red phosphorus flame retardant is larger than 70 μm, the dispersibility of the red phosphorus flame retardant tends to decrease, and if it is less than 5 μm, the fluidity tends to decrease. It is.
[0047]
And it is preferable to set content of the said red phosphorus flame retardant (D component) in the range of 0.1 to 2 weight% in the whole resin composition, Most preferably, it is 0.1 to 1.0 weight %. That is, if it is less than 0.1% by weight, in order to obtain the desired flame retardancy, the amount of the composite metal hydroxide (C component) is relatively increased, which tends to cause a decrease in fluidity. This is because when the amount exceeds 2% by weight, impurities such as phosphoric acid increase to cause a decrease in moisture resistance, and at the same time, when added in a large amount, there tends to be no flame retardancy.
[0048]
And the inorganic filler can be used for the resin composition for semiconductor sealing of this invention with the said AD component and the composite metal hydroxide of the conventional thin flat plate shape depending on the case. The inorganic filler is not particularly limited, and various conventionally known fillers include, for example, quartz glass powder, talc, silica powder, alumina powder, aluminum nitride powder, and silicon nitride powder. These may be used alone or in combination of two or more. And as said inorganic filler, it is preferable to use a silica powder from the point that the linear expansion coefficient of the hardened | cured material obtained can be reduced. Especially, it is especially preferable from the point of the favorable fluidity | liquidity of a resin composition to use a fused silica powder as a silica powder, especially a spherical fused silica powder. Moreover, in the said inorganic filler, it is preferable that the average particle diameter is the range of 10-70 micrometers, More preferably, it is 10-50 micrometers. That is, as described above, when the composite metal hydroxide has the particle size distributions (c1) to (c3) and the average particle size of the inorganic filler is within the above range, the resin composition is good. Fluidity is obtained. In addition, as the silica powder, a ground silica powder obtained by grinding a silica powder can be used in some cases.
[0049]
The content of the inorganic filler is preferably set to 60 to 95% by weight of the entire semiconductor sealing resin composition.
[0050]
The resin composition for semiconductor encapsulation according to the present invention requires a curing accelerator, a pigment, a release agent, a surface treatment agent, a flexibility imparting agent, etc. in addition to the components A to D and the inorganic filler. Depending on the case, it can be added appropriately.
[0051]
The curing accelerator is not particularly limited as long as it accelerates the reaction between an epoxy group and a hydroxyl group, and examples thereof include diazabicyclo such as 1,8-diazabicyclo (5,4,0) undecene-7. Examples include alkene compounds, tertiary amines such as triethylenediamine, imidazoles such as 2-methylimidazole, and phosphorus compounds such as triphenylphosphine. These compounds may be used alone or in combination of two or more.
[0052]
Examples of the pigment include carbon black and titanium oxide. Examples of the mold release agent include carnauba wax, polyethylene wax, paraffin, fatty acid ester, and fatty acid salt.
[0053]
Furthermore, examples of the surface treatment agent include coupling agents such as silane coupling agents. Examples of the flexibility-imparting agent include various silicone compounds and butadiene-acrylonitrile rubber.
[0054]
Moreover, in the resin composition for semiconductor encapsulation which concerns on this invention, in addition to said each component, you may use together an organic flame retardant. Examples of the organic flame retardant include nitrogen-containing organic compounds and phosphazene compounds, and nitrogen-containing organic compounds are particularly preferably used.
[0055]
Examples of the nitrogen-containing organic compound include compounds having a heterocyclic skeleton such as melamine derivatives, cyanurate derivatives, and isocyanurate derivatives. These organic flame retardants are used alone or in combination of two or more.
[0056]
The organic flame retardant may be blended after mechanically mixing with the complex metal hydroxide in advance, or the organic flame retardant is dissolved in a solvent and the complex metal hydroxide is added thereto. Then, a solvent-treated and surface-treated product may be used.
[0057]
And in the resin composition for semiconductor encapsulation which concerns on this invention, the suitable combination of each component containing the said AD component is as follows. That is, among epoxy resins (component A), biphenyl epoxy resins are preferable from the viewpoint of good fluidity, and phenol resins (component B) are preferably phenol aralkyl resins from the viewpoint of fluidity. And it is preferable to use what coated the surface of red phosphorus powder with the metal hydroxide and the phenol resin as a red phosphorus flame retardant (D component). Furthermore, it is preferable to use fused silica powder as the inorganic filler together with the polyhedral composite metal hydroxide (component C). Furthermore, in addition to these components, it is preferable to use waxes since the mold release property tends to be lowered when the above composite metal hydroxide is used.
[0058]
The resin composition for semiconductor encapsulation according to the present invention can be produced, for example, as follows. That is, epoxy resin (component A), phenol resin (component B), polyhedral complex metal hydroxide (component C), red phosphorus flame retardant (component D), inorganic filler, and other materials as required Additives are blended at a predetermined ratio. Next, the mixture is melt-kneaded in a heated state using a kneader such as a mixing roll machine, and cooled to room temperature. And the target resin composition for semiconductor sealing can be manufactured according to a series of processes of grind | pulverizing by a well-known means, and tableting as needed.
[0059]
Alternatively, a mixture of the above semiconductor sealing resin composition is introduced into a kneader and kneaded in a molten state, and then is continuously formed into a substantially cylindrical granule by a series of steps. A stopping resin composition can be produced.
[0060]
Further, the mixture of the resin composition for semiconductor encapsulation is received on a pallet, and after cooling, it is formed into a sheet by a method such as press rolling, roll rolling, or coating a mixture of solvent to form a sheet. A semiconductor sealing resin composition can be produced.
[0061]
The semiconductor element sealing method using the thus obtained semiconductor sealing resin composition (powder, tablet, granule, etc.) is not particularly limited, and is known as usual transfer molding or the like. The molding method can be used.
[0062]
Moreover, a semiconductor device by flip-chip mounting can be manufactured using the sheet-shaped resin composition for encapsulating a semiconductor, for example, as follows. That is, the resin composition for sealing a sheet-like semiconductor is disposed on the electrode surface side of a semiconductor element provided with bonding bumps or on the bump bonding part side of a circuit board, and the semiconductor element and the circuit board are bumped. A semiconductor device can be manufactured by flip-chip mounting by bonding and sealing the two together by resin sealing.
[0063]
Next, examples will be described together with comparative examples.
[0064]
First, each material shown below was prepared.
[0065]
〔Epoxy resin〕
4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetramethylbiphenyl
[0066]
[Phenolic resin]
Phenol aralkyl resin represented by the formula (4) (softening point 70 ° C., hydroxyl group equivalent 175)
[0067]
[Red phosphorus flame retardant]
The surface of red phosphorus powder coated with magnesium hydroxide and phenolic resin (red phosphorus content 93% by weight, average particle size 30 μm: Nova Excel, manufactured by Phosphor Chemical Industries)
[0068]
[Silica powder]
Fused silica powder (spherical, average particle size 25 μm, specific surface area 1.4 m²/ G)
[0069]
〔Silane coupling agent〕
β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane
[0070]
[Curing accelerator]
Triphenylphosphine
[0071]
[Composite metal hydroxide]
Next, prior to the examples, polyhedral composite metal hydroxides shown in Tables 1 and 2 below were prepared. The polyhedral complex metal hydroxide was prepared according to the method for producing the polyhedral complex metal hydroxide described above.
[0072]
[Table 1]

[0073]
[Table 2]

[0074]
Examples 1-8, Comparative Examples 1-3
Next, the components shown in Table 3 to Table 4 below are blended in the proportions shown in the table, melt-kneaded for 3 minutes in a mixing roll machine (temperature 100 ° C.), cooled and solidified, and then pulverized to obtain the desired powder An epoxy resin composition was obtained.
[0075]
[Table 3]

[0076]
[Table 4]

[0077]
Using the epoxy resin compositions of Examples and Comparative Examples obtained as described above, tablets were formed and molding conditions were 175 ° C. × 70 kg / cm.²X Flame retardant test pieces were molded in 120 seconds. Further, a package of LQFP-114 (size: 20 mm × 20 mm × thickness 1.4 mm) was molded with a TOWA automatic molding machine. Flame retardancy, wire flow and moisture resistance were measured and evaluated using these flame retardant test pieces and packages. Furthermore, after crushing the test piece, phosphate ions were extracted under extraction conditions of 160 ° C. × 20 hours, and the amount of ions was measured by ion chromatography analysis. These results are also shown in Tables 5 to 6 below.
[0078]
〔Flame retardance〕
Flame retardancy was evaluated according to the method of UL94 V-0 standard. In addition, a pass means a 94-V0 pass.
[0079]
[Wire flow]
Regarding the package, first, the occurrence of defects such as deformation of the gold wire was measured by observing a transmission image inside the package with a soft X-ray apparatus. As a result of the measurement, the case where the deformation of the gold wire was confirmed was evaluated as x, and the case where the deformation of the gold wire was not confirmed and a good package was obtained was evaluated as ◯.
[0080]
[Moisture resistance]
Using the semiconductor device thus manufactured, a pressure cooker test (PCT test) was performed by applying a bias (conditions: 130 ° C./85% RH, 30 V bias). In the failure mode, leakage failure and open failure were measured, and the time until occurrence of failure was obtained.
[0081]
[Table 5]

[0082]
[Table 6]

[0083]
From the results of Tables 5 and 6 above, the product of the example not only exhibits excellent flame retardancy, but also causes no problems in the wire flow, and the amount of phosphate ions is one comparative example using a red phosphorus flame retardant alone. Compared to the above, it was very little and good results were obtained in terms of moisture resistance. From these facts, it can be seen that they are excellent in all of flame retardancy, fluidity and moisture resistance. On the other hand, the product of Comparative Example 1 is a system of red phosphorus flame retardant alone, and good results were obtained with respect to flame retardancy and fluidity, but the amount of phosphate ions was large and the moisture resistance was poor. The product of Comparative Example 2 was a composite metal hydroxide alone system, had good fluidity, had a low amount of phosphate ions, and had no problem with moisture resistance, but failed the flame retardancy test. In addition, the comparative example 3 product is a composite metal hydroxide alone system, but because the composite metal hydroxide amount is set higher than the comparative example 2 product, it has good flame retardancy, In addition, since the amount of phosphate ions was small, there was no problem with respect to moisture resistance, but it was found that the fluidity was inferior because a problem occurred in the wire flow.
[0084]
Further, the epoxy resin component in Example 1 was changed to R in the formula (2).₁~ R_FourAnd a biphenyl type epoxy resin in which all of hydrogen becomes R, and R in the formula (2)₁~ R_FourThe biphenyl type epoxy resin in which all are methyl groups was replaced with a mixed type epoxy resin in which the weight ratio was 1: 1. Otherwise, the epoxy resin composition was prepared at the same blending ratio as in Example 1. Using this epoxy resin composition, the same measurement and evaluation as described above were performed, and as a result, good results substantially the same as those in the above examples were obtained.
[0085]
【The invention's effect】
  As described above, the present invention is represented by the general formula (1).And having the specific particle size distributionA polyhedral polyhydric composite metal hydroxide (C component) and a red phosphorus flame retardant (D component). Thus, since the polyhedral complex metal hydroxide and the red phosphorus flame retardant are used in combination as the flame retardant component, the individual addition amounts of the C component and D component for imparting flame retardancy are suppressed. can do. That is, adverse effects due to the use of only one side, for example, the use of only a polyhedral complex metal hydroxide, a decrease in fluidity due to a large amount of addition in imparting flame retardancy, and red phosphorus When the flame retardant is used alone, the amount of impurities such as phosphoric acid is large, resulting in a decrease in moisture resistance caused by this. However, it is possible to suppress the decrease in fluidity and the decrease in moisture resistance. Furthermore, due to the ion trapping effect of the polyhedral complex metal hydroxide, impurities such as phosphoric acid are reduced, and the effect of suppressing the decrease in moisture resistance becomes more effective. Therefore, what has the outstanding fluidity | liquidity and moisture resistance reliability with the outstanding flame retardance is obtained.
[0086]
When the red phosphorus-based flame retardant (component D) is coated with red phosphorus with a metal hydroxide and a phenol resin, oxidation of red phosphorus is prevented and the handling property is good because of stability. It becomes.
[0087]
Further, by setting the contents of the polyhedral complex metal hydroxide (C component) and the red phosphorus flame retardant (D component) within specific ranges, further excellent fluidity and moisture resistance can be obtained. It is done.
[Brief description of the drawings]
FIG. 1 is a scanning electron micrograph (magnification 50000 times) showing an example of the crystal shape of a polyhedral complex metal hydroxide used in the present invention.
FIG. 2 is a perspective view showing a hexagonal plate shape which is one of the crystal shapes of a conventional composite metal hydroxide.
FIGS. 3A and 3B are explanatory views showing the outer shape of a conventional composite metal hydroxide, wherein FIG. 3A is a plan view and FIG. 3B is a side view.
FIG. 4 is an explanatory view showing an example of the outer shape of the composite metal hydroxide of the present invention, wherein (a) is a plan view and (b) is a side view.
FIG. 5 is an explanatory view showing another example of the outer shape of the composite metal hydroxide of the present invention, wherein (a) is a plan view and (b) is a side view.

Claims (6)

Containing (A) ~ (D) the following components, and the component (C), semiconductor sealing resin composition characterized by chromatic particle size distribution (c1) ~ a (c3) shown below.
(A) Epoxy resin.
(B) Phenolic resin.
(C) A polyhedral complex metal hydroxide represented by the following general formula (1).
[Chemical 1]
m (M _a O _b ) · n (Q _d O _e ) · cH ₂ O (1)
[In the above formula (1), M and Q are different metal elements, and Q is a metal element belonging to a group selected from IVa, Va, VIa, VIIa, VIII, Ib, and IIb of the periodic table. . Further, m, n, a, b, c, d, and e are positive numbers, and may be the same value or different values. ]
(D) Red phosphorus flame retardant.
(C1) A particle size of less than 1.3 μm is 10 to 35% by weight.
(C2) The particle size is less than 1.3 to 2.0 μm and 50 to 65% by weight.
(C3) 10 to 30% by weight of particles having a particle size of 2.0 μm or more.   2. The resin composition for encapsulating a semiconductor according to claim 1, wherein the red phosphorus flame retardant as the component (D) is obtained by coating red phosphorus with a metal hydroxide and a phenol resin.   3. The resin composition for encapsulating a semiconductor according to claim 1, wherein the content of the polyhedral polyhedral metal hydroxide as the component (C) is 1 to 30% by weight of the entire resin composition.   Content of the red phosphorus flame retardant which is said (D) component is 0.1 to 2 weight% of the whole resin composition, The resin composition for semiconductor sealing as described in any one of Claims 1-3 object. A semiconductor encapsulating resin composition according to any one of claims 1 to 4, semiconductor encapsulation according to claim 1 containing a nitrogen-containing organic compound ing Resin composition. The semiconductor device formed by sealing a semiconductor element using the resin composition for semiconductor sealing as described in any one of Claims 1-5.

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