JP4147030B2 - Epoxy resin composition for semiconductor encapsulation and semiconductor device - Google Patents

Epoxy resin composition for semiconductor encapsulation and semiconductor device Download PDF

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Publication number
JP4147030B2
JP4147030B2 JP2001511113A JP2001511113A JP4147030B2 JP 4147030 B2 JP4147030 B2 JP 4147030B2 JP 2001511113 A JP2001511113 A JP 2001511113A JP 2001511113 A JP2001511113 A JP 2001511113A JP 4147030 B2 JP4147030 B2 JP 4147030B2
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Prior art keywords
epoxy resin
resin composition
flame retardant
boric acid
acid compound
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博義 小角
永井　　晃
巧 上野
亮 茂木
利昭 石井
博起 幸島
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Hitachi Ltd
Resonac Corp
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Hitachi Chemical Co Ltd
Hitachi Ltd
Showa Denko Materials Co Ltd
Resonac Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/29—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the material, e.g. carbon
    • H01L23/293—Organic, e.g. plastic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/38—Boron-containing compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31—Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32—Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321—Disposition
    • H01L2224/32151—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/32221—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/32245—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/4826—Connecting between the body and an opposite side of the item with respect to the body
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/484—Connecting portions
    • H01L2224/48463—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
    • H01L2224/48465—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732—Location after the connecting process
    • H01L2224/73201—Location after the connecting process on the same surface
    • H01L2224/73215—Layer and wire connectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732—Location after the connecting process
    • H01L2224/73251—Location after the connecting process on different surfaces
    • H01L2224/73265—Layer and wire connectors

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  • Polymers & Plastics (AREA)
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  • Structures Or Materials For Encapsulating Or Coating Semiconductor Devices Or Solid State Devices (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、難燃剤としてホウ酸化合物を含有し、燃焼時に有害ガスが発生しない環境に優れたエポキシ樹脂組成物及びそれを用いた半導体装置に関する。
【０００２】
【従来の技術】
トランジスタ、ＩＣ、ＬＳＩ等の半導体装置は量産性の点で有利な樹脂封止型が主流になっている。半導体封止用樹脂としては、エポキシ樹脂とフェノール樹脂硬化剤を配合した組成物が成形性、機械特性、吸湿特性及び接着性等の特性バランスが良く、しかも信頼性が優れている。
【０００３】
この半導体封止用樹脂組成物には難燃性を付与するために、臭素化エポキシ樹脂又は臭素化フェノール樹脂等の臭素化化合物と、アンチモン化合物とが添加されている。しかしながら、これらの化合物は燃焼時に有害ガスを発生し環境に悪影響を与える可能性があることが心配されている。
【０００４】
一方、半導体装置を高温下に放置した場合、臭素系化合物中から脱離した脱離臭素により半導体素子のアルミニウム配線パッドと金ワイヤとの接続部分が腐食されやすく、臭素無添加系に比べて短時間で断線、故障し易い。そのため自動車のエンジンルーム内や高温雰囲気下で用いる電気機器内の半導体装置はその塔載箇所が限定される。また、脱離臭素は半導体素子のアルミニウム配線の腐食そのものを促進させ、半導体装置の耐湿信頼性を低下させる原因になる。
【０００５】
難燃助剤であるアンチモンも腐食の一要因となる。すなわち、アンチモンと臭素が結合して臭素化アンチモンガスを発生し、このガスは更に臭素の脱離反応を促進させる。
このため、難燃性及び半導体装置の信頼性を同時に満足できる、有害ガスを発生しない半導体封止材料が強く望まれている。
【０００６】
半導体装置が高温高湿下で使用される場合でも半導体封止用樹脂組成物の臭素化合物から臭素の脱離を抑える方法として特許文献１は熱安定性の高いメタ位に臭素が配位した臭素化ビスフェノールＡ型エポキシ樹脂を用いること、特許文献２は脱離臭素を捕捉する無機ハイドロタルサイト系のイオン捕捉剤を用いることを開示する。また、特許文献３と特許文献４は赤リン系難燃剤を用いること、特許文献５はホウ酸亜鉛等のホウ酸系化合物をシリカと共に用いることを開示し非ハロゲン系難燃化手法を提示する。
【０００７】
更に特許文献６と特許文献７はフェノール樹脂、リン又は赤リン、窒素、ホウ素化合物、金属水和物から選ばれた非ハロゲン系難燃剤の２種以上の併用系を開示する。
しかしながら、上記の特許文献１で用いる臭素化エポキシ樹脂は、熱分解温度の上昇効果は極めて小さく、臭素の脱離を防止する効果が劣る。
【０００８】
また、特許文献２のイオン捕捉剤はその配合量を増やしても臭素補足能力に限界があり、配合量が多すぎると封止用樹脂組成物の成形性の低下や吸湿率が大きくなる問題が生じる。
【０００９】
特許文献３と特許文献４の非ハロゲン系難燃剤は難燃性の付与効果が臭素／アンチモン系に比ベてかなり劣る。このため、難燃性ＵＬ−９４規格Ｖ−０を満足するには、難燃剤を多量に配合する必要がある。該非ハロゲン系難燃剤を多量に配合した封止用樹脂組成物は成形性及び接着性の低下並びに吸湿率の増大を招くおそれがある。
【００１０】
そのため、非ハロゲン系難燃剤を用いた樹脂組成物は積層板や電気部品の絶縁材料に用途が限定されているのが現状である。
【００１１】
また、赤リンを難燃剤に用いる場合は爆発や発火しやすいので取り扱いには注意が必要である。
【特許文献１】
特開平５−３２０３１９号公報
【特許文献２】
特開平４−４８７５９号公報
【特許文献３】
特開平７−１５７５４２号公報
【特許文献４】
特開平７−１７３３７２号公報
【特許文献５】
特開平６−１０７９１４号公報
【特許文献６】
特開平７−３３１０３３号公報
【特許文献７】
特開平８−１５１５０５号公報
【００１２】
【発明が解決しようとする課題】
上述したように、半導体封止用樹脂組成物の難燃性と半導体装置の各種信頼性を同時に改善する半導体封止用樹脂組成物の開発が課題であり多くの方法が提案されている。
本発明は、上記の状況に鑑みなされたものであり、その目的とするところは、非ハロゲン系難燃剤を用いた難燃性と成形性に優れた半導体封止用エポキシ樹脂組成物及び該組成物で封止した半導体装置を提供することにある。
【００１３】
【課題を解決するための手段】
上記目的を達成するために、本発明者等は各種難燃剤について鋭意検討した。その結果、特定のホウ酸化合物を用いることにより上記目的を達成できることを見出した。本発明の要旨は次の通りである。
【００１４】
エポキシ樹脂、硬化剤、硬化促進剤、難燃剤を含むエポキシ樹脂組成物において、該難燃剤が式（１）
ｘＭ（ＩＩ）Ｏ・ｙＢ ２ Ｏ ３ ・ｚＨ ２ Ｏ…（１）
（式中、ｘ／ｙ＝０．２〜６．０、ｚ／ｙ＝０．２〜６．０、Ｍ（ＩＩ）は二価の金属を示す）で表される特定のホウ酸化合物よりなることを特徴とする。本発明は公知の各種難燃助剤を含むこともできる。
【００１５】
また、本発明は半導体素子の少なくとも一部が、エポキシ樹脂、硬化剤、硬化促進剤、難燃剤を含むエポキシ樹脂組成物で封止されてなる半導体装置において、該難燃剤が式（１）
ｘＭ（ＩＩ）Ｏ・ｙＢ ２ Ｏ ３ ・ｚＨ ２ Ｏ…（１）
（式中、ｘ／ｙ＝０．２〜６．０、ｚ／ｙ＝０．２〜６．０、Ｍ（ＩＩ）は二価の金属を示す）で表される特定のホウ酸化合物よりなることを特徴とする半導体装置を提供する。
【００１６】
本発明は、半導体素子の一方の面がダイパッドに接着され、該半導体素子の他方の面に外部接続用パッドが設けられ，該外部接続用パッドと外部リードとが導電ワイヤを介して接続され，少なくとも該半導体素子がエポキシ樹脂組成物で封止されている半導体装置であって、該エポキシ樹脂組成物の難燃剤が式（１）で表されるホウ酸化合物よりなることを特徴とする半導体装置を提供する。
【００１７】
また、本発明は、半導体素子と外部リードとが接着層を介して接続され、該半導体素子の該接着層を有する面側に設けられた外部接続パッドと該外部リードとが導電ワイヤによって接続され、少なくとも半導体素子の一部がエポキシ樹脂組成物で封止されてなる半導体装置において、該エポキシ樹脂組成物の難燃剤が式（１）で表されるホウ酸化合物よりなることを特徴とする半導体装置を提供する。
【００１８】
上記について、更に詳しく説明する。
本発明において、式（１）で表されるホウ酸化合物は式中、ｘ／ｙ＝０．２〜６．０、ｚ／ｙ＝０．２〜６．０である。
【００１９】
ｘ／ｙが０．２未満では品質の安定したホウ酸化合物の合成が難しくなり、所望の特性即ち難燃性ＵＬ−９４規格Ｖ−０を満足する特性が得られない。ｘ／ｙが６．０以上になると難燃作用が低下し、実用に供しなくなる。実質的に好適な範囲は０．５〜３．０である。
【００２０】
ｚ／ｙ＝０．２〜６．０は化合物中における結晶水の割合を示し、ｚ／ｙが６．０を越えると脱水温度が低下する傾向が見られ、それに伴って難燃効果も低下する。ｚ／ｙが０．２未満では含水比率が少ないため、消火に必要な水の相対量が得られず、結果的には難燃性が不十分になる。
【００２１】
一般式（１）のＭは二価の金属を表し、具体的にはカルシウム（Ｃａ），マグネシウム（ Ｍｇ），ベリリウム（ Ｂｅ），ストロンチウム（Ｓｒ），バリウム（Ｂａ）、鉄（Ｆｅ）等があるが、これらの中では特にカルシウム（Ｃａ）、マグネシウム（Ｍｇ）、ベリリウム（Ｂｅ）が最も難燃性及び成形性が優れている。
【００２２】
更には、必要に応じて例えば一般式（１）のＭが亜鉛、銅、ニッケル、マンガン、鉄等のホウ酸化合物を併用できる。
その配合比率は目的、用途に応じて適宜選択されるものであり、特に制約されるものではない。
【００２３】
本発明のホウ酸化合物は、例えば下記の（Ａ）〜（Ｄ）の工程により製造できる。
（Ａ）３５００Ｃ．Ｃの水にホウ砂２５０ｇ、ホウ酸５４０ｇを添加した溶液を作成する。
（Ｂ）５００Ｃ．Ｃの水にカルシウム、マグネシウム、ベリリウム、バリウム、鉄等の各種成分酸化物７０ｇ、９０％以上の濃硫酸９０ｇを含有した溶液を作成する。
（Ｃ）上記（Ａ）と（Ｂ）を２４時間攪拌混合する。
（Ｄ）（Ｃ）で得られた沈殿物を濾過し、水とアセトンで複数回繰り返し洗浄する。
本発明のホウ酸化合物の製造方法は、上記に特定されるものではなく、市販の化合物を用いてもよい。
【００２４】
本発明において、式（１）で表されるホウ酸化合物の粒子径として５μｍ以下を５０重量％以上にすることにより同じ添加量で難燃効果をより高くすることができる。粒子径が５μｍを越える粒子が５０重量％以上と多くなるとエポキシ樹脂組成物中での分散性が悪くなるため、一部に偏在が生じやすくなり結果的には難燃性が低下する。更に好ましくはホウ酸化合物の粒子径が０．５〜３μｍである。
【００２５】
本発明において、式（１）で表されるホウ酸化合物として脱水温度が３５０℃以上の化合物を用いることにより、同じ添加量で難燃効果をより高くできる。その理由はエポキシ樹脂の分解温度が２８０〜３４０℃であることから、エポキシ樹脂の分解ガスに着火した後に脱水し、その水で消火するためと考える。
【００２６】
特性変動が少ない品質の安定したホウ酸化合物を合成するためには、ホウ酸化合物の脱水温度の上限が６００℃位であることが好ましい。脱水温度の上限６００℃は難燃性作用を充分に発揮する温度でもある。
【００２７】
本発明において、式（１）で表されるホウ酸化合物の添加量はエポキシ樹脂１００重量部に対して、２〜８０重量部であることが好ましい。２重量部未満ではホウ酸化合物量が不足しＵＬ−９４規格Ｖ−０を満足しない。また８０重量部を超えるとホウ酸化合物によってはエポキシ樹脂組成物の成形時の流動性が低下し、トランスファー成形した際に金型内の材料流路の狭部が未充填となる場合がある。そのため薄型小型パッケージの半導体装置では安定した成形品が得られず、成形品形状に限定を受ける。
【００２８】
本発明において、式（１）で表されるホウ酸化合物と窒素化合物、金属水和化合物、金属酸化物の少なくとも一種よりなる難燃助剤とを併用することにより、半導体封止用として各種信頼性に優れたエポキシ樹脂組成物を提供できる。
【００２９】
ホウ酸化合物単独に比ベてこれら窒素化合物、金属水和化合物、金属酸化物のうち一種、あるいは数種を併用することにより、その難燃特性における相乗効果が得られ、少ない添加量で難燃性ＵＬ−９４規格Ｖ−０を達成できる。このため、封止用樹脂組成物の成形性、電気特性、機械特性、接着性等の他の特性に与える影響も少ない。
【００３０】
上記の窒素化合物としては、例えばトリアジン化合物、メラミン及びその誘導体、メラミン硫酸塩、メラミンシアヌレート及びその誘導体、硫酸アンモニウム、ベンゾグアナミン及びその誘導体、シアヌール酸、イソシアヌール酸、メラミンフェノール及びその誘導体等が挙げられる。
【００３１】
上記の金属水和化合物としては、例えばアルミニウム（Ａｌ）、カルシウム（Ｃａ），マグネシウム（Ｍｇ），ベリリウム（Ｂｅ），ストロンチウム（Ｓｒ），バリウム（Ｂａ）等の金属の水酸化物等が挙げられる。これらの中でも水酸化アルミニウム、水酸化マグネシウム、水酸化バリウム等が好ましい。
【００３２】
また、上記の金属酸化物としては、例えば酸化銅、酸化亜鉛、酸化セシウム、酸化鉄、酸化チタン、酸化モリブデン、酸化マンガン、酸化バリウム、酸化アルミニウム、酸化コバルト、酸化ニッケル、酸化インジウム、酸化錫、酸化タングステン、酸化ビスマス、酸化ストロンチウム等が挙げられる。
【００３３】
これら難燃助剤の添加量はホウ酸化合物１００重量部に対して０．１〜１００重量部の範囲が好ましい。
【００３４】
本発明の半導体封止用エポキシ樹脂組成物において、エポキシ樹脂は特に限定するものでなく、半導体封止用として通常使用されている公知のものを用いることが出来る。例えば、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、 ビスフェノールＡ、ビスフェノールＦ及びビスフェノールＳ型エポキシ樹脂等のビスフェノール類エポキシ樹脂、フェノールまたはクレゾールベースの３官能以上の多官能エポキシ樹脂、ビフェニル骨格、ナフタレン骨格、またはジシクロペンタジエン骨格を有する２官能または３官能のエポキシ樹脂等が挙げられる。
【００３５】
本発明において、硬化剤は１分子当たり１個以上のフェノール性水酸基を有するフェノール化合物が好ましく、特にフェノール性水酸基を２個以上有する化合物が好ましい。例えば、フェノールノボラック樹脂、フェノールとアラルキルエーテルとの重縮合物、ビスフェノール樹脂、オルトクレゾールノボラック樹脂、ポリパラビニルフェノール等が挙げられる。
【００３６】
硬化促進剤としては、アミン系の１，８ジアザビシクロ（５，４，０）−ウンデセン−７、イミダゾール系の２−メチルイミダゾール及びリン系のトリフェニルホスフィン等の公知のものを使用することができる。
【００３７】
本発明では、必要に応じて強靭化や低弾性率化及び接着性、離形性等の特性向上を目的に、充填剤、可とう化剤、カップリング剤、滑剤、着色剤等を配合することができる。
充填剤としては、公知の無機系及び有機系の充填剤を使用できる。その中でも特に溶融シリカ、結晶シリカ、アルミナ、炭酸カルシウム、ケイ酸ジルコニウム、ケイ酸カルシウム、タルク、クレー、マイカ等の微粉末が成形性と熱膨張係数、電気特性、機械強度のバランスを計る上で好ましい。
【００３８】
該充填剤の粒子径は０．１〜３０μｍが好ましく、０．５〜１０μｍが特に好ましい。平均粒径０．１μｍ未満ではエポキシ樹脂組成物のチキソ性が高くなり、粘度が著しく上昇して成形が難しくなる。また、平均粒子径が３０μｍを越えると金型内の材料流路の狭部への材料充填ができなくなったり、樹脂成分と充填剤が分離し易くなり安定した成形品が得られなくなる。また、可撓化剤、カップリング剤、滑剤、着色剤等についても公知のものを用いることができる。
【００３９】
【発明の実施の形態】
以下、実施例を用いて具体的に説明する。
【００４０】
【実施例】
表１に実施例１〜９で用いたエポキシ樹脂、フェノール樹脂硬化剤、難燃助剤及び硬化促進剤を示す。表２にホウ酸化合物系難燃剤の種類、ｘ／ｙ、ｚ／ｙ、平均粒径、脱水温度及び添加量を示す。そして、表３は実施例１〜９で用いた樹脂組成物の配合組成と成形性、難燃性の評価結果を示す。
【００４１】
本発明において、難燃性の評価はＵＬ−９４規格に従って行った。具体的には下記の方法で作成した短冊状の樹脂板（試験片）を用いて、該樹脂板の一方の端にガスバーナーの炎を近ずけ樹脂板を燃焼着火（第一着火）させ所定時間保持した後、ガスバーナーの炎を樹脂板から遠ざけ樹脂板の炎が消える迄の時間を測定する。その後、再度、同じ樹脂板の第１回着火部にガスバーナーで着火（第二着火）し、前回と同様炎が消える迄の時間を測定する。該測定を１種の樹脂組成物に付き５個の試験片を用いて測定し、その平均値が最大１０秒以内、合計５０秒以内の時Ｖ−０と判定する。それに対して最大３０秒以内、平均２５０秒以内の場合はＶ−１となる。
【００４２】
測定用試験片には、エポキシ樹脂組成物をトランスファープレスを用い、金型温度１８０℃、成形圧力７０ｋｇｆ／ｃｍ２、成形時間９０秒で作成したアズモールド試片と、アズモールド試片を更に１８０℃で５時間加熱硬化させた後硬化試片とを用意した。試験片厚さは、いずれとも１／１６インチ（１．６ｍｍ）である。
【００４３】
成形性の評価はスパイラルフローをＥＭＭＩ−１−６６に準じ、試験片作成と同じ条件で成形した時の成形品長さを測定することで行った。
【００４４】
【表１】

Figure 0004147030
【００４５】
【表２】
Figure 0004147030
【００４６】
【表３】
Figure 0004147030
【００４７】
該実施例で用いた無機充填剤は平均粒径３〜１５μｍの角形シリカ及び平均粒径５μｍ以下の球形シリカと、平均粒径１０〜５０μｍの球形シリカの混合物である。カップリング剤としてエポキシシラン、離型剤としてモンタン酸エステルロウ、着色剤としてカーボンブラックを用いた。表１に示す各配合組成物をそれぞれ直径８インチの二軸加熱ロールを用い、ロール表面温度約６０〜９０℃で１０分間混練した。
【００４８】
実施例１に示すように本発明の特定のホウ酸化合物を難燃剤に用いることにより、ホウ酸化合物単独でも後硬化試片でＵＬ−９４規格のＶ−０を達成することができる。比較例と比ベると化合物中の金属酸化物とホウ酸の比率（ｘ／ｙ）、水和量（ｚ／ｙ）を規定することにより難燃効果の優れたホウ酸化合物を得ることができた。
【００４９】
実施例２に示すようにホウ酸化合物の粒径の小さいものを選択して５μｍ以下の含有量を７０重量％（５０重量％以上）にすることにより、実施例１に比ベて難燃剤がより少量でＵＬ−９４規格のＶ−０を達成できる。これは難燃剤のエポキシ樹脂中における分散性が向上して難燃効果が高まったためと考える。
【００５０】
実施例３に示すようにホウ酸化合物として、脱水温度がエポキシ樹脂の分解温度より高い、４３０℃（３５０℃以上）の材料を用いることにより、実施例１に比ベて難燃剤がより少量でＵＬ−９４規格のＶ−０を達成することができる。
【００５１】
この場合後硬化工程を施していない、アズモールド品でもＵＬ−９４規格のＶ−０を満足することが可能になる。一般的にエポキシ樹脂組成物は後硬化することによって難燃性が向上する。これは架橋密度があがることにより燃焼時に炭素残査を形成しやすいためと考える。
【００５２】
最近の半導体装置は量産性向上と低価格化を目的に、後硬化工程を省略した所謂アズモールド品のままで出荷する検討が行われている。本発明は難燃性を損なうことなく量産時のプロセス省略化の実現に対して貢献できる。
実施例４〜９に示すように本発明の特定のホウ酸化合物の量を２〜８０重量部にすることにより、後硬化試片の難燃性をＵＬ−９４規格のＶ−０を維持しながら成形性の目安であるスパイラルフローを長くすることができる。この値が長いほど流動性がよい材料であり、大面積の成形品を一括で形成できるため、製品の多数個取りができ量産性向上に貢献できる。
【００５３】
実施例５、８、９に示すように本発明の特定のホウ酸化合物をより効果的に使う手法として相乗効果の期待できる難燃助剤との組合せが有効である。難燃助剤を併用することによりホウ酸カルシウムの量を低減することができ、高流動性でかつアズモールド品のままでＵＬ−９４規格のＶ−０を満足することが可能になる。
図１は実施例５の難燃剤としてメタホウ酸ナトリウムを用いたもの及び実施例５中の難燃剤をメタホウ酸カルシウムからホウ酸亜鉛に代えたものについてそれぞれのアズモールド品［充填剤含有量（ＦＣ）８０重量％］における、難燃剤の添加量と燃焼最大時間（秒）の関係を示す。
【００５４】
また、図２は難燃剤の添加量と燃焼総計時間（秒）の関係を示す。
図１及び図２に示すように、本発明のメタホウ酸カルシウムを用いた場合は、ホウ酸亜鉛を用いた場合にくらべて添加量が１０部以下の少量でも格段に燃焼最大時間（秒）と燃焼総計時間（秒）が短くなり、優れた難燃性を示す。
【００５５】
実施例５では窒素化合物の代表例としてメラミン、実施例８では金属水和化合物の代表例として水酸化マグネシウム、実施例９では金属酸化物の代表例として酸化鉄を用いた。
【００５６】
比較例１はｘ／ｙが０．１で化合物中のホウ酸に比べて金属酸化物の比率が少ない例である。この場合平均粒径の大きい材料しか得られず、エポキシとの分散性が悪いため少量しか添加できずＵＬ−９４規格のＶ−０を達成することはできなかった。
【００５７】
比較例２はｘ／ｙが８．０及びｚ／ｙが１０で化合物中のホウ酸比率が少ない例である。この場合ホウ酸化合物を大量に添加しても難燃性の効果が低く、ＵＬ−９４規格のＶ−０を達成することはできなかった。またホウ酸化合物を大量に添加することによりスパイラルフローが低くなり成形性が低下する傾向にある。
【００５８】
図３に実施例１で得られたエポキシ樹脂組成物で半導体素子を封止した半導体装置の例を示す。
【００５９】
本実施例の半導体装置は半導体素子１がダイパッド２上に銀ペースト等の接着層４を介して塔載されている。該半導体素子１の電気回路を有する面に外部接続用パッド６が設けられ，該パッドと外部リード３とが導電性ワイヤ５で電気的に接続されている。該半導体装置を、前記外部リード３の一部を除いて実施例１で得られたエポキシ樹脂組成物７により封止した。樹脂封止はトランスファー成形プレスを用いて、金型温度１８０℃、成形圧力７０ｋｇｆ／ｃｍ２、成形時間９０秒の条件で行った。得られた半導体装置は１２１℃、２気圧のプレッシャ・クッカ釜中で２０００時間放置するプレッシャ・クッカ試験を行って、配線の腐食状況を検査した。その結果、腐食による配線の断線はなく正常に動作した。
【００６０】
図４に実施例５で得られたエポキシ樹脂組成物で半導体素子を封止した半導体装置の例を示す。
【００６１】
本実施例の半導体装置は半導体素子１の電気回路（図示せず）を有する面の一部と外部リード３とが接着層８で接着されている。前記電気回路を有する面の一部に外部接続用パッド６が設けられ，該パッドと前記外部リード３とが導電性ワイヤ５により電気的に接続されている。該半導体装置を、前記外部リード３の一部を除いて実施例５で得られたエポキシ樹脂組成物７で封止した。樹脂封止はトランスファー成形プレスを用い、金型温度１８０℃、成形圧力７０ｋｇｆ／ｃｍ２、成形時間９０秒の条件で行った。
得られた半導体装置は１２１℃、２気圧のプレッシャ・クッカ釜中で２０００時間放置後も配線の腐食による断線がなく正常に動作した。
【００６２】
【発明の効果】
本発明のエポキシ樹脂組成物は、ハロゲン、アンチモン及びリン系等の難燃剤を使わずに特定のホウ酸化合物で極めて効果的に難燃化したものであり、環境の点で優れている。また、成形性や硬化物の耐熱院、耐湿性の点で優れている。このため、本発明のエポキシ樹脂組成物で封止した半導体装置は高密度化、高集積度化、小型薄型化、軽量化に対応でき工業的価値は極めて大きい。
【図面の簡単な説明】
【図１】難燃剤をメタホウ酸カルシウムとホウ酸亜鉛とした場合の難燃剤の添加量と燃焼最大時間（秒）の関係を示す図。
【図２】難燃剤をメタホウ酸カルシウムとホウ酸亜鉛とした場合の難燃剤の添加量と燃焼総計時間（秒）の関係を示す図。
【図３】本発明の半導体封止用エポキシ樹脂組成物で封止した半導体装置の断面図。
【図４】本発明の別の半導体封止用エポキシ樹脂組成物で封止した別の半導体装置の断面図[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an epoxy resin composition excellent in an environment containing a boric acid compound as a flame retardant and generating no harmful gas during combustion, and a semiconductor device using the same.
[0002]
[Prior art]
For semiconductor devices such as transistors, ICs, and LSIs, a resin-encapsulated type that is advantageous in terms of mass productivity has become mainstream. As a semiconductor sealing resin, a composition in which an epoxy resin and a phenol resin curing agent are blended has a good balance of properties such as moldability, mechanical properties, moisture absorption properties, and adhesiveness, and is excellent in reliability.
[0003]
A brominated compound such as brominated epoxy resin or brominated phenol resin and an antimony compound are added to the resin composition for encapsulating a semiconductor in order to impart flame retardancy. However, there is a concern that these compounds may generate harmful gases during combustion and adversely affect the environment.
[0004]
On the other hand, when the semiconductor device is left at a high temperature, the connection between the aluminum wiring pad and the gold wire of the semiconductor element is easily corroded by the desorbed bromine desorbed from the bromine-based compound, which is shorter than the bromine-free system. It is easy to break and break down in time. For this reason, the mounting locations of semiconductor devices in the engine room of an automobile or in electrical equipment used in a high temperature atmosphere are limited. Further, the desorbed bromine promotes corrosion of the aluminum wiring of the semiconductor element, and causes a decrease in moisture resistance reliability of the semiconductor device.
[0005]
Antimony, a flame retardant aid, also contributes to corrosion. That is, antimony and bromine are combined to generate brominated antimony gas, which further promotes the elimination reaction of bromine.
For this reason, there is a strong demand for a semiconductor sealing material that can simultaneously satisfy the flame retardancy and the reliability of the semiconductor device and does not generate harmful gases.
[0006]
Patent Document 1 discloses bromine in which bromine is coordinated at a meta position having high thermal stability as a method for suppressing the elimination of bromine from a bromine compound of a resin composition for encapsulating a semiconductor even when the semiconductor device is used under high temperature and high humidity. Patent Document 2 discloses the use of a bisphenol A-type epoxy resin, and the use of an inorganic hydrotalcite-based ion scavenger that traps desorbed bromine. Patent Documents 3 and 4 disclose that a red phosphorus flame retardant is used, and Patent Document 5 discloses that a boric acid compound such as zinc borate is used together with silica, and presents a non-halogen flame retardant method. .
[0007]
Furthermore, Patent Document 6 and Patent Document 7 disclose a combined system of two or more non-halogen flame retardants selected from phenol resin, phosphorus or red phosphorus, nitrogen, boron compound, and metal hydrate.
However, the brominated epoxy resin used in the above-mentioned Patent Document 1 has an extremely small effect of increasing the thermal decomposition temperature, and is inferior in the effect of preventing the elimination of bromine.
[0008]
In addition, the ion scavenger of Patent Document 2 has a limit in bromine capture ability even when the blending amount is increased, and if the blending amount is too large, there is a problem that the moldability of the sealing resin composition is lowered and the moisture absorption rate is increased. Arise.
[0009]
The non-halogen flame retardants of Patent Document 3 and Patent Document 4 are considerably inferior in flame retardancy compared to bromine / antimony systems. For this reason, in order to satisfy the flame retardancy UL-94 standard V-0, it is necessary to mix | blend a flame retardant in large quantities. A sealing resin composition containing a large amount of the non-halogen flame retardant may cause a decrease in moldability and adhesiveness and an increase in moisture absorption.
[0010]
Therefore, the present situation is that the use of the resin composition using the non-halogen flame retardant is limited to insulating materials for laminated plates and electrical parts.
[0011]
In addition, when red phosphorus is used as a flame retardant, it is easy to explode or ignite, so it must be handled with care.
[Patent Document 1]
JP-A-5-320319 [Patent Document 2]
Japanese Patent Laid-Open No. 4-48759 [Patent Document 3]
JP-A-7-157542 [Patent Document 4]
JP-A-7-173372 [Patent Document 5]
JP-A-6-107914 [Patent Document 6]
Japanese Patent Laid-Open No. 7-331033 [Patent Document 7]
JP-A-8-151505 gazette
[Problems to be solved by the invention]
As described above, the development of a resin composition for semiconductor encapsulation that simultaneously improves the flame retardancy of the resin composition for semiconductor encapsulation and various reliability of the semiconductor device is an issue, and many methods have been proposed.
The present invention has been made in view of the above situation, and the object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation excellent in flame retardancy and moldability using a non-halogen flame retardant and the composition. An object of the present invention is to provide a semiconductor device sealed with an object.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors have intensively studied various flame retardants. As a result, it has been found that the above object can be achieved by using a specific boric acid compound. The gist of the present invention is as follows.
[0014]
In the epoxy resin composition containing an epoxy resin, a curing agent, a curing accelerator, and a flame retardant, the flame retardant is represented by the formula (1).
xM (II) O · y B 2 O 3 · z H 2 O ... (1)
(Wherein, x / y = 0.2 to 6.0, z / y = 0.2 to 6.0, M (II) represents a divalent metal) It is characterized by becoming. The present invention can also contain various known flame retardant aids.
[0015]
According to the present invention, in the semiconductor device in which at least a part of the semiconductor element is sealed with an epoxy resin composition containing an epoxy resin, a curing agent, a curing accelerator, and a flame retardant, the flame retardant is represented by the formula (1).
xM (II) O · y B 2 O 3 · z H 2 O ... (1)
(Wherein, x / y = 0.2 to 6.0, z / y = 0.2 to 6.0, M (II) represents a divalent metal) A semiconductor device is provided.
[0016]
In the present invention, one surface of a semiconductor element is bonded to a die pad, an external connection pad is provided on the other surface of the semiconductor element, the external connection pad and an external lead are connected via a conductive wire, A semiconductor device in which at least the semiconductor element is sealed with an epoxy resin composition, wherein the flame retardant of the epoxy resin composition comprises a boric acid compound represented by the formula (1) I will provide a.
[0017]
Further, according to the present invention, the semiconductor element and the external lead are connected via an adhesive layer, and the external connection pad provided on the surface side of the semiconductor element having the adhesive layer and the external lead are connected by a conductive wire. A semiconductor device in which at least a part of a semiconductor element is sealed with an epoxy resin composition, wherein the flame retardant of the epoxy resin composition comprises a boric acid compound represented by the formula (1) Providing equipment.
[0018]
The above will be described in more detail.
In this invention, the boric acid compound represented by Formula (1) is x / y = 0.2-6.0 and z / y = 0.2-6.0 in a formula.
[0019]
When x / y is less than 0.2, it is difficult to synthesize a boric acid compound with stable quality, and desired characteristics, that is, characteristics satisfying flame retardancy UL-94 standard V-0 cannot be obtained. When x / y is 6.0 or more, the flame retarding action is lowered and it is not practically used. A substantially preferred range is 0.5 to 3.0.
[0020]
z / y = 0.2 to 6.0 indicates the ratio of water of crystallization in the compound. When z / y exceeds 6.0, the dehydration temperature tends to decrease, and the flame retardancy also decreases accordingly. To do. If z / y is less than 0.2, the water content is small, so that the relative amount of water necessary for fire extinguishing cannot be obtained, resulting in insufficient flame retardancy.
[0021]
M in the general formula (1) represents a divalent metal, specifically, calcium (Ca), magnesium (Mg), beryllium (Be), strontium (Sr), barium (Ba), iron (Fe), etc. Among these, calcium (Ca), magnesium (Mg), and beryllium (Be) are particularly excellent in flame retardancy and moldability.
[0022]
Furthermore, for example, M in the general formula (1) may be used in combination with a boric acid compound such as zinc, copper, nickel, manganese, iron, and the like as necessary.
The blending ratio is appropriately selected according to the purpose and application, and is not particularly limited.
[0023]
The boric acid compound of the present invention can be produced, for example, by the following steps (A) to (D).
(A) 3500C. A solution is prepared by adding 250 g of borax and 540 g of boric acid to C water.
(B) 500C. A solution containing 70 g of various component oxides such as calcium, magnesium, beryllium, barium, iron and 90 g of concentrated sulfuric acid of 90% or more in water of C is prepared.
(C) The above (A) and (B) are mixed with stirring for 24 hours.
(D) The precipitate obtained in (C) is filtered and washed repeatedly with water and acetone several times.
The manufacturing method of the boric acid compound of the present invention is not specified above, and a commercially available compound may be used.
[0024]
In the present invention, by setting the particle diameter of the boric acid compound represented by the formula (1) to 5 μm or less to 50% by weight or more, the flame retardant effect can be further enhanced with the same addition amount. When the number of particles having a particle diameter exceeding 5 μm is as large as 50% by weight or more, dispersibility in the epoxy resin composition is deteriorated, so that uneven distribution is likely to occur in part and consequently flame retardancy is lowered. More preferably, the particle diameter of the boric acid compound is 0.5 to 3 μm.
[0025]
In the present invention, by using a compound having a dehydration temperature of 350 ° C. or higher as the boric acid compound represented by the formula (1), the flame retardant effect can be further enhanced with the same addition amount. The reason is that since the decomposition temperature of the epoxy resin is 280 to 340 ° C., the decomposition gas of the epoxy resin is ignited and then dehydrated and extinguished with the water.
[0026]
In order to synthesize a stable boric acid compound of a quality with little characteristic fluctuation, the upper limit of the dehydration temperature of the boric acid compound is preferably about 600 ° C. The upper limit of 600 ° C. for the dehydration temperature is also a temperature at which the flame-retardant action is sufficiently exhibited.
[0027]
In this invention, it is preferable that the addition amount of the boric-acid compound represented by Formula (1) is 2-80 weight part with respect to 100 weight part of epoxy resins. If it is less than 2 parts by weight, the amount of boric acid compound is insufficient and does not satisfy UL-94 standard V-0. On the other hand, when it exceeds 80 parts by weight, depending on the boric acid compound, the fluidity at the time of molding the epoxy resin composition may be lowered, and the narrow part of the material flow path in the mold may be unfilled when transfer molding is performed. Therefore, a stable molded product cannot be obtained in a thin and small package semiconductor device, and the shape of the molded product is limited.
[0028]
In the present invention, a combination of a boric acid compound represented by the formula (1) and a flame retardant aid composed of at least one of a nitrogen compound, a metal hydrated compound, and a metal oxide can be used for semiconductor encapsulation. An epoxy resin composition having excellent properties can be provided.
[0029]
By using one or several of these nitrogen compounds, metal hydrated compounds, and metal oxides in combination with boric acid compounds alone, a synergistic effect in their flame retardant properties can be obtained, and flame retardant with a small addition amount UL-94 standard V-0 can be achieved. For this reason, there is little influence which it has on other characteristics, such as the moldability of the resin composition for sealing, an electrical property, a mechanical characteristic, and adhesiveness.
[0030]
Examples of the nitrogen compound include triazine compounds, melamine and derivatives thereof, melamine sulfate, melamine cyanurate and derivatives thereof, ammonium sulfate, benzoguanamine and derivatives thereof, cyanuric acid, isocyanuric acid, melamine phenol and derivatives thereof, and the like. .
[0031]
Examples of the metal hydrate compound include metal hydroxides such as aluminum (Al), calcium (Ca), magnesium (Mg), beryllium (Be), strontium (Sr), and barium (Ba). . Among these, aluminum hydroxide, magnesium hydroxide, barium hydroxide and the like are preferable.
[0032]
Examples of the metal oxide include copper oxide, zinc oxide, cesium oxide, iron oxide, titanium oxide, molybdenum oxide, manganese oxide, barium oxide, aluminum oxide, cobalt oxide, nickel oxide, indium oxide, tin oxide, Examples include tungsten oxide, bismuth oxide, strontium oxide, and the like.
[0033]
The addition amount of these flame retardant aids is preferably in the range of 0.1 to 100 parts by weight with respect to 100 parts by weight of the boric acid compound.
[0034]
In the epoxy resin composition for semiconductor encapsulation of the present invention, the epoxy resin is not particularly limited, and known ones usually used for semiconductor encapsulation can be used. For example, phenol novolac type epoxy resin, cresol novolak type epoxy resin, bisphenol epoxy resins such as bisphenol A, bisphenol F and bisphenol S type epoxy resins, phenol or cresol-based trifunctional or higher functional epoxy resin, biphenyl skeleton, naphthalene Examples thereof include a bifunctional or trifunctional epoxy resin having a skeleton or a dicyclopentadiene skeleton.
[0035]
In the present invention, the curing agent is preferably a phenol compound having one or more phenolic hydroxyl groups per molecule, and particularly preferably a compound having two or more phenolic hydroxyl groups. For example, phenol novolac resin, polycondensate of phenol and aralkyl ether, bisphenol resin, ortho-cresol novolac resin, polyparavinylphenol and the like can be mentioned.
[0036]
As the curing accelerator, known ones such as amine-based 1,8 diazabicyclo (5,4,0) -undecene-7, imidazole-based 2-methylimidazole, and phosphorus-based triphenylphosphine can be used. .
[0037]
In the present invention, a filler, a flexible agent, a coupling agent, a lubricant, a colorant, and the like are blended as needed for the purpose of improving properties such as toughness, low elastic modulus, adhesion, and releasability. be able to.
As the filler, known inorganic and organic fillers can be used. Among these, fine powders such as fused silica, crystalline silica, alumina, calcium carbonate, zirconium silicate, calcium silicate, talc, clay, and mica are particularly suitable for balancing the moldability, thermal expansion coefficient, electrical properties, and mechanical strength. preferable.
[0038]
The particle size of the filler is preferably from 0.1 to 30 μm, particularly preferably from 0.5 to 10 μm. If the average particle size is less than 0.1 μm, the thixotropy of the epoxy resin composition is increased, the viscosity is remarkably increased, and molding becomes difficult. On the other hand, if the average particle diameter exceeds 30 μm, the material cannot be filled into the narrow part of the material flow path in the mold, or the resin component and the filler are easily separated, and a stable molded product cannot be obtained. Moreover, well-known things can be used also about a flexible agent, a coupling agent, a lubricant, a coloring agent, etc.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a specific description will be given using examples.
[0040]
【Example】
Table 1 shows the epoxy resin, phenol resin curing agent, flame retardant aid and curing accelerator used in Examples 1-9. Table 2 shows the types, x / y, z / y, average particle size, dehydration temperature, and addition amount of boric acid compound flame retardants. Table 3 shows the composition of the resin composition used in Examples 1 to 9, the moldability, and the evaluation results of flame retardancy.
[0041]
In the present invention, the flame retardancy was evaluated according to the UL-94 standard. Specifically, using a strip-shaped resin plate (test piece) prepared by the following method, close the flame of the gas burner to one end of the resin plate and ignite the resin plate (first ignition). After holding for a predetermined time, the flame of the gas burner is kept away from the resin plate and the time until the flame of the resin plate disappears is measured. Thereafter, the first ignition portion of the same resin plate is again ignited with a gas burner (second ignition), and the time until the flame disappears is measured as before. The measurement is performed using five test pieces per one resin composition, and when the average value is within 10 seconds at the maximum and within 50 seconds in total, it is determined as V-0. On the other hand, when it is within 30 seconds at maximum and within 250 seconds on average, it becomes V-1.
[0042]
As a test specimen for measurement, an epoxy resin composition was transferred using a transfer press, an as-mold specimen prepared with a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm 2 and a molding time of 90 seconds, and an as-mold specimen further 180 A cured specimen was prepared after heat curing at 5 ° C. for 5 hours. Each specimen thickness is 1/16 inch (1.6 mm).
[0043]
The moldability was evaluated by measuring the length of a molded product when the spiral flow was molded according to EMMI-1-66 under the same conditions as the test piece preparation.
[0044]
[Table 1]
Figure 0004147030
[0045]
[Table 2]
Figure 0004147030
[0046]
[Table 3]
Figure 0004147030
[0047]
The inorganic filler used in the examples is a mixture of square silica having an average particle diameter of 3 to 15 μm, spherical silica having an average particle diameter of 5 μm or less, and spherical silica having an average particle diameter of 10 to 50 μm. Epoxysilane was used as a coupling agent, montanic acid ester wax as a release agent, and carbon black as a colorant. Each compounding composition shown in Table 1 was kneaded for 10 minutes at a roll surface temperature of about 60 to 90 ° C. using a biaxial heating roll having a diameter of 8 inches.
[0048]
By using the specific boric acid compound of the present invention as a flame retardant as shown in Example 1, UL-94 standard V-0 can be achieved with a post-curing specimen even with a boric acid compound alone. Comparing with the comparative example, it is possible to obtain a boric acid compound having an excellent flame retardant effect by defining the ratio of metal oxide and boric acid in the compound (x / y) and the amount of hydration (z / y). did it.
[0049]
As shown in Example 2, by selecting a boric acid compound having a small particle size and setting the content of 5 μm or less to 70% by weight (50% by weight or more), the flame retardant is compared with Example 1. The V-0 of the UL-94 standard can be achieved with a smaller amount. This is considered to be because the flame retardant effect is enhanced by improving the dispersibility of the flame retardant in the epoxy resin.
[0050]
As shown in Example 3, by using a material of 430 ° C. (350 ° C. or higher) whose dehydration temperature is higher than the decomposition temperature of the epoxy resin as the boric acid compound, the amount of flame retardant is smaller than that of Example 1. UL-094 V-0 can be achieved.
[0051]
In this case, even an as-molded product that has not undergone a post-curing process can satisfy V-0 of the UL-94 standard. In general, flame retardancy is improved by post-curing an epoxy resin composition. This is considered to be because carbon residue is easily formed at the time of combustion due to an increase in crosslink density.
[0052]
Recently, for the purpose of improving mass productivity and reducing the cost, semiconductor devices are being shipped out in the form of so-called as-molded products in which the post-curing process is omitted. The present invention can contribute to the realization of process omission at the time of mass production without impairing flame retardancy.
By setting the amount of the specific boric acid compound of the present invention to 2 to 80 parts by weight as shown in Examples 4 to 9, the flame retardancy of the post-cured specimen is maintained at V-0 of UL-94 standard. However, it is possible to lengthen the spiral flow, which is a measure of formability. The longer this value is, the better the fluidity of the material, and large-area molded products can be formed at one time, so that a large number of products can be obtained, contributing to the improvement of mass productivity.
[0053]
As shown in Examples 5, 8, and 9, a combination with a flame retardant aid that can be expected to have a synergistic effect is effective as a method of using the specific boric acid compound of the present invention more effectively. By using a flame retardant aid together, the amount of calcium borate can be reduced, and it is possible to satisfy UL-094 V-0 with high fluidity and an as-molded product.
FIG. 1 shows each as-molded product [filler content (FC) for the one using sodium metaborate as the flame retardant of Example 5 and for the one in which the flame retardant in Example 5 was changed from calcium metaborate to zinc borate. ) 80 wt%] shows the relationship between the amount of flame retardant added and the maximum combustion time (seconds).
[0054]
FIG. 2 shows the relationship between the amount of flame retardant added and the total combustion time (seconds).
As shown in FIGS. 1 and 2, when the calcium metaborate of the present invention is used, the maximum combustion time (seconds) can be remarkably increased even when the addition amount is 10 parts or less, compared with the case where zinc borate is used. The total combustion time (seconds) is shortened and excellent flame retardancy is exhibited.
[0055]
In Example 5, melamine was used as a representative example of a nitrogen compound, in Example 8, magnesium hydroxide was used as a representative example of a metal hydrated compound, and in Example 9, iron oxide was used as a representative example of a metal oxide.
[0056]
Comparative Example 1 is an example in which x / y is 0.1 and the ratio of the metal oxide is smaller than boric acid in the compound. In this case, only a material having a large average particle diameter was obtained, and since the dispersibility with epoxy was poor, only a small amount could be added, and the UL-94 standard V-0 could not be achieved.
[0057]
Comparative Example 2 is an example in which x / y is 8.0 and z / y is 10, and the boric acid ratio in the compound is small. In this case, even if a large amount of a boric acid compound was added, the effect of flame retardancy was low, and UL-094 V-0 could not be achieved. Further, when a large amount of boric acid compound is added, the spiral flow is lowered and the moldability tends to be lowered.
[0058]
FIG. 3 shows an example of a semiconductor device in which a semiconductor element is sealed with the epoxy resin composition obtained in Example 1.
[0059]
In the semiconductor device of this embodiment, a semiconductor element 1 is mounted on a die pad 2 via an adhesive layer 4 such as a silver paste. An external connection pad 6 is provided on the surface of the semiconductor element 1 having an electric circuit, and the pad and the external lead 3 are electrically connected by a conductive wire 5. The semiconductor device was sealed with the epoxy resin composition 7 obtained in Example 1 except for a part of the external lead 3. Resin sealing was performed using a transfer molding press under conditions of a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm 2 , and a molding time of 90 seconds. The obtained semiconductor device was subjected to a pressure / cooker test in which it was left in a pressure / cooker pot at 121 ° C. and 2 atm for 2000 hours to inspect the corrosion status of the wiring. As a result, there was no disconnection of the wiring due to corrosion, and it operated normally.
[0060]
FIG. 4 shows an example of a semiconductor device in which a semiconductor element is sealed with the epoxy resin composition obtained in Example 5.
[0061]
In the semiconductor device of this embodiment, a part of the surface of the semiconductor element 1 having an electric circuit (not shown) and the external lead 3 are bonded by an adhesive layer 8. An external connection pad 6 is provided on a part of the surface having the electric circuit, and the pad and the external lead 3 are electrically connected by a conductive wire 5. The semiconductor device was sealed with the epoxy resin composition 7 obtained in Example 5 except for a part of the external lead 3. Resin sealing was performed using a transfer molding press under conditions of a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm 2 , and a molding time of 90 seconds.
The obtained semiconductor device operated normally without disconnection due to wiring corrosion even after being left in a pressure cooker pot at 121 ° C. and 2 atm for 2000 hours.
[0062]
【The invention's effect】
The epoxy resin composition of the present invention is very effectively flame-retardant with a specific boric acid compound without using flame retardants such as halogen, antimony and phosphorus, and is excellent in terms of environment. In addition, it is excellent in terms of moldability, heat resistance of cured products, and moisture resistance. For this reason, the semiconductor device encapsulated with the epoxy resin composition of the present invention can cope with higher density, higher integration, smaller size, thinner and lighter, and its industrial value is extremely large.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the amount of flame retardant added and the maximum combustion time (seconds) when the flame retardant is calcium metaborate and zinc borate.
FIG. 2 is a graph showing the relationship between the amount of flame retardant added and the total combustion time (seconds) when the flame retardant is calcium metaborate and zinc borate.
FIG. 3 is a cross-sectional view of a semiconductor device encapsulated with an epoxy resin composition for encapsulating a semiconductor according to the present invention.
FIG. 4 is a cross-sectional view of another semiconductor device sealed with another epoxy resin composition for sealing a semiconductor according to the present invention.

Claims (8)

エポキシ樹脂、硬化剤、硬化促進剤、難燃剤を含むエポキシ樹脂組成者において、該難燃剤が式（１）
ｘＭ（ＩＩ）Ｏ・ｙＢ ２ Ｏ ３ ・ｚＨ ２ Ｏ…（１）
（式中、ｘ／ｙ＝０．２〜６．０、ｚ／ｙ＝０．２〜６．０、Ｍ（ＩＩ）はカルシウム（Ｃａ），マグネシウム（Ｍｇ），ベリリウム（Ｂｅ），バリウム（Ｂａ），鉄（Ｆｅ）のいずれかである）で表されるホウ酸化合物よりなることを特徴とするエポキシ樹脂組成物。In an epoxy resin composition containing an epoxy resin, a curing agent, a curing accelerator, and a flame retardant, the flame retardant is represented by the formula (1).
xM (II) O · y B 2 O 3 · z H 2 O ... (1)
(Wherein x / y = 0.2 to 6.0, z / y = 0.2 to 6.0, M (II) is calcium (Ca), magnesium (Mg), beryllium (Be), barium ( An epoxy resin composition comprising a boric acid compound represented by Ba) or iron (Fe). 請求項１記載のエポキシ樹脂組成物において、前記式（１）で表されるホウ酸化合物は粒子径が５μｍ以下のものを５０重量％以上含むことを特徴とするエポキシ樹脂組成物。  2. The epoxy resin composition according to claim 1, wherein the boric acid compound represented by the formula (1) contains 50% by weight or more of particles having a particle diameter of 5 μm or less. 請求項１記載のエポキシ樹脂組成物において、前記式（１）で表されるホウ酸化合物は脱水温度が３５０℃以上のものであることを特徴とするエポキシ樹脂組成物。  The epoxy resin composition according to claim 1, wherein the boric acid compound represented by the formula (1) has a dehydration temperature of 350 ° C. or higher. 請求項１記載のエポキシ樹脂組成物において、前記式（１）で表されるホウ酸化合物の配合量はエポキシ樹脂１００重量部に対して、２〜８０重量部であることを特徴とするエポキシ樹脂組成物。  The epoxy resin composition according to claim 1, wherein the compounding amount of the boric acid compound represented by the formula (1) is 2 to 80 parts by weight with respect to 100 parts by weight of the epoxy resin. Composition. 請求項１記載のエポキシ樹脂組成物において、窒素化合物、金属水和化合物及び金属酸化物から選ばれる難燃助剤の少なくとも一種を含むことを特徴とするエポキシ樹脂組成物。  The epoxy resin composition according to claim 1, comprising at least one flame retardant aid selected from a nitrogen compound, a metal hydrated compound, and a metal oxide. 半導体素子の少なくとも一部が、エポキシ樹脂、硬化剤、硬化促進剤、難燃剤を含むエポキシ樹脂組成物で封止されてなる半導体装置において、該難燃剤が式（１）
ｘＭ（ＩＩ）Ｏ・ｙＢ ２ Ｏ ３ ・ｚＨ ２ Ｏ…（１）
（式中、ｘ／ｙ＝０．２〜６．０、ｚ／ｙ＝０．２〜６．０、Ｍ（ＩＩ）はカルシウム（Ｃａ），マグネシウム（Ｍｇ），ベリリウム（Ｂｅ），バリウム（Ｂａ），鉄（Ｆｅ）のいずれかである）で表されるホウ酸化合物よりなることを特徴とする樹脂封止型半導体装置。In a semiconductor device in which at least a part of a semiconductor element is sealed with an epoxy resin composition containing an epoxy resin, a curing agent, a curing accelerator, and a flame retardant, the flame retardant is represented by the formula (1).
xM (II) O · y B 2 O 3 · z H 2 O ... (1)
(Wherein x / y = 0.2 to 6.0, z / y = 0.2 to 6.0, M (II) is calcium (Ca), magnesium (Mg), beryllium (Be), barium ( A resin-encapsulated semiconductor device comprising a boric acid compound represented by Ba) or iron (Fe). 半導体素子の一方の面がダイパッドに接着され、該半導体素子の他方の面に外部接続用パッドが設けられ，該外部接続用パッドが導電ワイヤを介して外部リードに接続され、少なくとも該半導体素子がエポキシ樹脂組成物により封止されている樹脂封止型半導体装置であって、該エポキシ樹脂組成物が式（１）
ｘＭ（ＩＩ）Ｏ・ｙＢ ２ Ｏ ３ ・ｚＨ ２ Ｏ…（１）
（式中、ｘ／ｙ＝０．２〜６．０、ｚ／ｙ＝０．２〜６．０、Ｍ（ＩＩ）はカルシウム（Ｃａ），マグネシウム（Ｍｇ），ベリリウム（Ｂｅ），バリウム（Ｂａ），鉄（Ｆｅ）のいずれかである）で表されるホウ酸化合物よりなる難燃剤を含むことを特徴とする樹脂封止型半導体装置。One surface of the semiconductor element is bonded to a die pad, an external connection pad is provided on the other surface of the semiconductor element, the external connection pad is connected to an external lead through a conductive wire, and at least the semiconductor element is A resin-encapsulated semiconductor device encapsulated with an epoxy resin composition, wherein the epoxy resin composition has the formula (1)
xM (II) O · y B 2 O 3 · z H 2 O ... (1)
(Wherein x / y = 0.2 to 6.0, z / y = 0.2 to 6.0, M (II) is calcium (Ca), magnesium (Mg), beryllium (Be), barium ( A resin-encapsulated semiconductor device comprising a flame retardant composed of a boric acid compound represented by Ba) or iron (Fe). 半導体素子と、該半導体素子の一方の面の一部に接着層を介して接続された外部リードと、該半導体素子の前記接着層を有する側に設けられた外部接続用パッドと、該パッドと該外部リードとを接続する導電ワイヤとを有し、少なくとも半導体素子がエポキシ樹脂組成物により封止されている樹脂封止型半導体装置であって、該エポキシ樹脂組成物が式（１）
ｘＭ（ＩＩ）Ｏ・ｙＢ ２ Ｏ ３ ・ｚＨ ２ Ｏ…（１）
（式中、ｘ／ｙ＝０．２〜６．０、ｚ／ｙ＝０．２〜６．０、Ｍ（ＩＩ）はカルシウム（Ｃａ），マグネシウム（Ｍｇ），ベリリウム（Ｂｅ），バリウム（Ｂａ），鉄（Ｆｅ）のいずれかである）で表されるホウ酸化合物よりなる難燃剤を含むことを特徴とする樹脂封止型半導体装置。A semiconductor element, an external lead connected to a part of one surface of the semiconductor element via an adhesive layer, an external connection pad provided on the side of the semiconductor element having the adhesive layer, and the pad A resin-encapsulated semiconductor device having a conductive wire connected to the external lead, wherein at least a semiconductor element is encapsulated with an epoxy resin composition, wherein the epoxy resin composition has the formula (1)
xM (II) O · y B 2 O 3 · z H 2 O ... (1)
(Wherein x / y = 0.2 to 6.0, z / y = 0.2 to 6.0, M (II) is calcium (Ca), magnesium (Mg), beryllium (Be), barium ( A resin-encapsulated semiconductor device comprising a flame retardant composed of a boric acid compound represented by Ba) or iron (Fe).
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