JP4595223B2 - Thermosetting resin composition, epoxy resin molding material and semiconductor device - Google Patents

Description

（Ｐはリン原子、Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４は置換もしくは無置換の芳香族基、またはアルキル基、Ａ_１は２価の芳香族基、Ｂ_１は単結合またはエーテル基、スルホン基、スルフィド基、カルボニル基から選ばれる２価の置換基または炭素原子数１〜１３で構成される２価の有機基を表す。ｍは０≦ｍ＜１の数を示す。）
【０００６】
【化６】

（Ｐはリン原子、Ｒ₁、Ｒ₂、Ｒ₃およびＲ₄は置換もしくは無置換の芳香族基、またはアルキル基、Ａ₂は２価の芳香族基を示す。ｍは０≦ｍ＜１の数を示す。）
【０００９】
［２］第［１］項記載のエポキシ樹脂成形材料で半導体素子を封止してなることを特徴とする半導体装置、
である。
これらを用いることにより、極めて硬化性と保存性が良好なエポキシ樹脂成形材料を得ることができる。
【００１０】
【発明の実施の形態】
本発明に用いる１分子内にエポキシ基を２個以上有する化合物（Ａ）は、１分子内にエポキシ基を２個以上有するものであれば、何ら制限はなく、例えばビフェニル型エポキシ樹脂、ノボラック型エポキシ樹脂、ナフタレン型エポキシ樹脂などビフェノールなどのフェノール類やフェノール樹脂、ナフトール類などの水酸基にエピクロロヒドリンを反応させて得られるエポキシ樹脂、エポキシ化合物などが挙げられる。その他に脂環式エポキシ樹脂のようにオレフィンを過酸を用いて酸化させエポキシ化したエポキシ樹脂や、ハイドロキノン等のジヒドロキシベンゼン類をエピクロロヒドリンでエポキシ化したものなどが挙げられる。
【００１１】
また１分子内にフェノール性水酸基を２個以上有する化合物（Ｂ）は、１分子内にエポキシ基を２個以上有する化合物（Ａ）の硬化剤として作用するものである。具体的にはフェノールノボラック樹脂、クレゾールノボラック樹脂、アルキル変性ノボラック樹脂（シクロアルケンの二重結合をフリーデルクラフツ型の反応でフェノール類と反応、共縮合した樹脂を含む）、フェノールアラルキル樹脂、ナフトール類とフェノール類をカルボニル基含有化合物と共縮合した樹脂などが例示されるが、１分子内で芳香族性の環に結合する水素原子が、水酸基で２個以上置換された化合物であればよい。
【００１２】
本発明において硬化促進剤として作用する分子化合物（Ｃ）は、一般式（１）または一般式（２）で示され、テトラ置換ホスホニウムとフェノール化合物との分子会合体である。１個のテトラ置換ホスホニウムカチオンと、１個以上３個未満のフェノール性水酸基および１個のフェノキシドアニオンの単位で構成され、テトラ置換ホスホニウムイオンの正電荷の周囲を１個以上３個未満のフェノール性水酸基と１個のフェノキシドアニオンが取り囲み、安定化した構造となっているものと考えられる。
【００１３】
このような構造をとり得るホスホニウムイオンは、置換または無置換のアリール基やアルキル基を置換基として有するテトラ置換ホスホニウムイオンが、熱や加水分解に対して安定であり好ましく、具体的にはテトラフェニルホスホニウム、テトラトリルホスホニウムなどのテトラアリール置換ホスホニウム、トリフェニルメチルホスニウムなどのトリアリールホスフィンとアルキルハライドから合成されたトリアリールモノアルキルホスホニウム、テトラブチルホスホニウムなどのテトラアルキル置換ホスホニウムなどが例示される。
【００１４】
また分子化合物（Ｃ）を形成するもう一方の成分である、フェノール化合物としては、ビスフェノールＡ（２，２−ビス（４−ヒドロキシフェニル）プロパン）、ビスフェノールＦ（４，４’−メチレンビスフェノール、２，４’−メチレンビスフェノール、２，２−メチレンビスフェノール）、ビス（４−ヒドロキシフェニル）スルホン（ビスフェノールＳ）、ビスフェノールＥ（４，４’−エチリデンビスフェノール）、ビスフェノールフルオレン（４，４’−（９Ｈ−フルオレン−９−イリデン）ビスフェノール）、４，４’−メチリデンビス（２，６−ジメチルフェノール）、ビス（４−ヒドロキシフェニル）メタノンなどのビスフェノール類、４，４’−ビフェノール、２，２’−ビフェノール、３，３’，５，５’−テトラメチルビフェノール、２，２−ビス（４−ヒドロキシフェニル）１，１，１−３，３，３−ヘキサフルオロプロパンなどのビフェノール類、ヒドロキノン、レゾルシノール、カテコール、ビス（４−ヒドロキシフェニル）エーテル、２，６−ジヒドロキシナフタレン、１，４−ジヒドロキシナフタレン、２，３−ジヒドロキシナフタレン、１，６−ジヒドロキシナフタレン、１，１’−ビ−２−ナフトール、１，４−ジヒドロキシアントラキノンなどが例示されるが、分子化合物の安定性や硬化性、硬化物物性の点で、ビスフェノールＡ、ビスフェノールＦ（４，４’−メチレンビスフェノール、２，４’−メチレンビスフェノール、２，２’−メチレンビスフェノールや、本州化学工業（株）製ビスフェノールＦ−Ｄのようなこれらの異性体混合物を含む）、ビスフェノールＳ、４，４’−ビフェノール、２，２−ビス（４−ヒドロキシフェニル）１，１，１−３，３，３−ヘキサフルオロプロパン、ビス（４−ヒドロキシフェニル）エーテル
２，３−ジヒドロキシナフタレンが好適である。
【００１５】
分子化合物（Ｃ）は、前述のようなフェノール化合物と最終的に脱ハロゲン化水素を助ける塩基、例えば水酸化ナトリウム、水酸化カリウムなどのアルカリ金属水酸化物や、ピリジン、トリエチルアミンなどの有機塩基をアルコールなどの溶媒に溶解し、続いて適当な溶媒に溶解した前記テトラ置換ホスホニウムのハライドを添加し反応させて、最終的には再結晶や再沈殿などの操作により固形分として取り出す方法や、テトラ置換ホスホニウムテトラ置換ボレートとフェノール化合物を熱反応後、アルコールなどの溶媒中で加熱反応させる方法で合成可能である。
【００１６】
本発明に用いる分子化合物（Ｃ）は、前述のようにホスホニウム−フェノキシド型の塩を構造に有するが、これが従来のホスホニウム−有機酸アニオン塩型の化合物と異なる点は、分子化合物（Ｃ）では、フェノール性水酸基のプロトンが関与した水素結合による高次構造が、このイオン結合を取り囲んでいる点である。従来の塩では、イオン結合の強さのみにより反応性を制御していたのに対し、分子化合物（Ｃ）では、常温では反応活性点のイオン対が高次構造により囲い込まれて活性点が保護され、一方実際の成形の段階においては、この高次構造が崩れることで活性点がむき出しになり、反応性を発現する、いわゆる潜伏性が付与されている。
【００１７】
本発明に用いる硬化促進剤として作用する分子化合物（Ｃ）の配合量は、１分子内にエポキシ基を２個以上有する化合物（Ａ）と硬化剤として作用する１分子内にフェノール性水酸基を２個以上有する化合物（Ｂ）の合計重量を１００重量部とした場合、０．５〜２０重量部程度が硬化性、保存性、他特性のバランスがよく好適である。また１分子内にエポキシ基を２個以上有する化合物（Ａ）と１分子内にフェノール性水酸基を２個以上有する化合物（Ｂ）の配合比率は、１分子内にエポキシ基を２個以上有する化合物（Ａ）のエポキシ基１モルに対し、１分子内にフェノール性水酸基を２個以上有する化合物（Ｂ）のフェノール性水酸基と分子化合物（Ｃ）に含まれるフェノール性水酸基との合算にて０．５〜２モル、好ましくは０．８〜１．２程度のモル比となるよう用いると、硬化性、耐熱性、電気特性等がより良好となる。
【００１８】
本発明に用いる無機充填材（Ｄ）の種類については、特に制限はなく、一般に封止材料に用いられているものを使用することができる。例えば溶融破砕シリカ粉末、溶融球状シリカ粉末、結晶シリカ粉末、２次凝集シリカ粉末、アルミナ、チタンホワイト、水酸化アルミニウム、タルク、クレー、ガラス繊維等が挙げられ、特に溶融球状シリカ粉末が好ましい。形状は限りなく真球状であることが好ましく、又、粒子の大きさの異なるものを混合することにより充填量を多くすることができる。
【００１９】
この無機充填材の配合量としては、１分子内にエポキシ基を２個以上有する化合物（Ａ）と１分子内にフェノール性水酸基を２個以上有する化合物（Ｂ）の合計量１００重量部あたり、２００〜２４００重量部が好ましい。２００重量部未満だと無機充填材による補強効果が充分に発現しないおそれがあり、２４００重量部を越えると、成形材料の流動性が低下し成形時に充填不良等が生じるおそれがあるので好ましくない。特に無機充填材の配合量が、前記成分（Ａ）と（Ｂ）の合計量１００重量部あたり、２５０〜１４００重量部であれば、成形材料の硬化物の吸湿率が低くなり、半田クラックの発生を防止することができ、更に溶融時の成形材料の粘度が低くなるため、半導体装置内部の金線変形を引き起こすおそれがなく、より好ましい。又無機充填材は、予め充分混合しておくことが好ましい。
【００２０】
本発明のエポキシ樹脂成形材料は、（Ａ）〜（Ｄ）成分の他に、必要に応じてγ−グリシドキシプロピルトリメトキシシラン等のカップリング剤、カーボンブラック等の着色剤、臭素化エポキシ樹脂、酸化アンチモン、リン化合物等の難燃剤、シリコーンオイル、シリコーンゴム等の低応力成分、天然ワックス、合成ワックス、高級脂肪酸もしくはその金属塩類、パラフィン等の離型剤、酸化防止剤等の各種添加剤を配合することができ、また、本発明において硬化促進剤として機能する分子化合物（Ｃ）の特性を損なわない範囲で、トリフェニルホスフィン、１，８−ジアザビシクロ（５，４，０）ウンデセン−７、２−メチルイミダゾール等の触媒と併用しても何ら問題はない。
【００２１】
本発明のエポキシ樹脂成形材料は、（Ａ）〜（Ｄ）成分及びその他の添加剤等をミキサーを用いて常温混合し、ロール、押出機等の混練機で混練し、冷却後粉砕して得られる。
本発明のエポキシ樹脂成形材料を用いて、半導体等の電子部品を封止し、半導体装置を製造するには、トランスファーモールド、コンプレッションモールド、インジェクションモールド等の成形方法で硬化成形することができる。
本発明のエポキシ樹脂成形材料の硬化物で封止された半導体装置は、本発明の技術的範囲に含まれ、優れた耐湿性を示す。
【００２２】
【実施例】
以下に、本発明の実施例を示すが、本発明はこれにより何ら制限を受けるものではない。
[硬化促進剤の合成]
以下、合成した分子化合物（Ｃ）の構造確認は、ＮＭＲ、元素分析および次の方法による中和滴定（ホスホニウムフェノキシド当量の測定）により実施した。
合成した分子化合物（Ｃ）をメタノール／水系溶媒中で、重量既知の過剰量のシュウ酸と反応させ、残余のシュウ酸を規定度既知の水酸化ナトリウム水溶液で定量して、分子化合物（Ｃ）の重量あたり規定度（Ｎ／ｇ）を算出した。この値の逆数がホスホニウムフェノキシド当量となる。
【００２３】
（合成例１）
撹拌装置付きの１リットルのセパラブルフラスコに日華化学工業（株）・製ＢＰＳ−Ｎ（４，４’−ビスフェノールＳを主成分とする）３７．５ｇ（０．１５モル）、メタノール１００ｍｌを仕込み、室温で撹拌溶解し、さらに攪拌しながら水酸化ナトリウム４．０ｇ（０．１モル）を予め、５０ｍｌのメタノールで溶解した溶液を添加した。次いで予めテトラフェニルホスホニウムブロマイド４１．９ｇ（０．１モル）を１５０ｍｌのメタノールに溶解した溶液を加えた。しばらく攪拌を継続し、３００ｍｌのメタノールを追加した後、フラスコ内の溶液を大量の水に撹拌しながら滴下し、白色沈殿を得た。沈殿を濾過、乾燥し、白色結晶６６．０ｇを得た。この化合物をＣ１とする。Ｃ１は、ＮＭＲ、マスペクトル、元素分析の結果から、テトラフェニルホスホニウム１分子と４，４’−ビスフェノールＳとが、モル比１：１．５で錯化した目的の分子化合物であることが確認された。また中和滴定の値からホスホニウムフェノキシド当量が、理論値７１３に近く、前述の構造を示した。合成の収率は９２．６％であった。
（合成例２〜６）
合成例２〜６では、表１に示した条件により、基本的な操作はすべて合成例1と同様に行い、それぞれ化合物Ｃ２〜Ｃ６を調製した。結果を表１に示す。
【００２４】
（比較合成例１）
撹拌装置付きの１リットルのセパラブルフラスコに、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）メタンを１２．８ｇ（０．０５モル）、メタノール５０ｍｌを仕込み、室温で撹拌溶解し、さらに攪拌しながら水酸化ナトリウム４．０ｇ（０．１モル）を、予め５０ｍｌのメタノールで溶解した溶液を添加した。次いで、予めテトラブチルホスホニウムブロマイド３３．９ｇ（０．１モル）を１５０ｍｌのメタノールに溶解した溶液を加えた。しばらく攪拌を継続し、フラスコ内に純水１００ｍｌを撹拌しながら滴下し、さらに２−プロパノール１００ｍｌを加え白色沈殿を得た。沈殿を濾過、乾燥し、白色結晶を得た。この化合物をＤ１とする。合成例１と同様の分析を行った結果、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）メタンの２個の水酸基のプロトンが解離した各々のフェノキシドに、各１分子のテトラブチルホスホニウムが、１：２でイオン結合した化合物であった。このＤ１は、単なるホスホニウム塩であって、本発明に用いる分子化合物ではない。
【００２５】
（比較合成例２）
撹拌装置付きの１リットルのセパラブルフラスコに、ｐ−フェニルフェノール１７．０ｇ（０．１モル）、メタノール５０ｍｌを仕込み室温で撹拌溶解し、さらに攪拌しながら水酸化ナトリウム４．０ｇ（０．１モル）を、予め５０ｍｌのメタノールで溶解した溶液を添加した。次いで、予めテトラフェニルホスホニウムブロミド４１．９ｇ（０．１モル）を１５０ｍｌのメタノールに溶解した溶液を加えた。しばらく攪拌を継続し、フラスコ内に純水１００ｍｌを撹拌しながら滴下し、さらに２−プロパノール１００ｍｌを加え白色沈殿を得た。沈殿を濾過、乾燥し、白色結晶を得た。この化合物をＤ２とする。合成例１と同様の分析を行った結果、ｐ−フェニルフェノールの水酸基のプロトンが脱離したフェノキシドに、１分子のテトラフェニルホスホニウムが、１：１でイオン結合した化合物であった。このＤ２は、単なるホスホニウム塩であって、本発明に用いる分子化合物ではない。
【００２６】
（比較合成例３）
撹拌装置付きの１リットルセパラブルフラスコに、安息香酸１２．２ｇ（０．１モル）、メタノール５０ｍｌを仕込み室温で撹拌溶解し、さらに攪拌しながら水酸化ナトリウム４．０ｇ（０．１モル）を、予め５０ｍｌのメタノールで溶解した溶液を添加した。次いで、予めテトラフェニルホスホニウムブロミド４１．９ｇ（０．１モル）を１５０ｍｌのメタノールに溶解した溶液を加えた。しばらく攪拌を継続し、フラスコ内の溶液を１００ｍｌの水に撹拌しながら滴下し、さらに２−プロパノール１００ｍｌを加え白色沈殿を得た。沈殿を濾過、乾燥し、白色結晶を得た。この化合物をＤ３とする。合成例１と同様の分析を行った結果、安息香酸のカルボキシル基のプロトンが脱離したカルボキシラートに、１分子のテトラフェニルホスホニウムが、１：１でイオン結合した化合物であった。このＤ３は、単なるホスホニウム塩であって、本発明に用いる分子化合物ではない。
比較合成例の結果も、他の合成例と同様に表１にまとめた。
【００２７】
【表１】

【００２８】
[熱硬化性樹脂組成物の評価]
まず、合成した分子化合物（Ｃ）を、１分子内にエポキシ基を２個以上有する化合物（Ａ）と、１分子内にフェノール性水酸基を２個以上有する化合物（Ｂ）、に加えて粉砕混合し、さらに１００℃で５分間、熱板上で溶融混練した後、冷却粉砕して組成物のサンプルを調製し評価を行った。評価方法は、下記のとおりである。
（１）硬化トルク
前記のサンプル調製方法により作製した組成物を用いて、キュラストメーター（オリエンテック社・製、ＪＳＲキュラストメーターＰＳ型）により、１７５℃で、４５秒後のトルクを求めた。キュラストメーターにおけるトルクは、硬化性のパラメータであり、この値の大きい方が硬化性は良好である。単位はｋｇｆ・ｃｍ。
（２）硬化発熱量残存率（保存性評価）
前記のサンプル調製方法により作製した組成物を用いて、調製直後の初期硬化発熱量および４０℃で３日間保存処理後の硬化発熱量を測定し、初期硬化発熱量（ｍＪ／ｍｇ）に対する保存処理後の硬化発熱量（ｍＪ／ｍｇ）の百分率を算出した。尚硬化発熱量の測定は、昇温速度１０℃／分の条件で、示差熱分析により測定した。この値が大きいほど、保存性が良好であることを示す。
【００２９】
（実施例１〜６および比較例１〜４）
実施例１〜６および比較例１〜４について、表２に示した配合により、前記の方法で、組成物のサンプルを調製し評価した。比較例１では、実施例における化合物（Ｃ）にかえてトリフェニルホスフィンを、比較例２〜４では、前述比較合成例１〜３で合成された化合物Ｄ１〜Ｄ３を用いた。得られた各組成物の評価結果は、表２に示した通りであった。
【００３０】
【表２】

【００３１】
実施例に示すように、本発明の熱硬化性樹脂組成物は、硬化性、保存性が良好であるのに対し、比較例１のトリフェニルホスフィンを硬化促進剤に用いた樹脂組成物は、硬化性、保存性とも悪く、比較例２〜４の本発明に用いる分子化合物ではないホスホニウム塩は、硬化性はよいものの保存性が劣る。
【００３２】

を混合し、熱ロールを用いて、９５℃で８分間混練して冷却後粉砕し、エポキシ樹脂成形材料を得た。得られたエポキシ樹脂成形材料を、以下の方法で評価した。結果を表３に示す。
【００３３】
評価方法
（１）スパイラルフローは、ＥＭＭＩ−Ｉ−６６に準じたスパイラルフロー測定用の金型を用い、金型温度１７５℃、注入圧力７０ｋｇ／ｃｍ²、硬化時間２分で測定した。スパイラルフローは、流動性のパラメータであり、大きい数値を示す方が良好な流動性を示す。単位はｃｍ。
（２）硬化トルクは、キュラストメーター（オリエンテック（株）製、ＪＳＲキュラストメーターＩＶＰＳ型）を用い、１７５℃、４５秒後のトルクを測定した。この値の大きい方が硬化性は良好である。単位はｋｇｆ・ｃｍ
（３）フロー残存率は、調製直後と３０℃で１週間保存した後のスパイラルフローを測定し、調製直後のスパイラルフローに対する保存後の百分率として表した。単位は％。
（４）耐湿信頼性は、金型温度１７５℃、圧力７０ｋｇ／ｃｍ²、硬化時間２分で１６ｐＤＩＰを成形し、この成形物を１７５℃で８時間の後硬化を行った後、１２５℃、相対湿度１００％の水蒸気中で、２０Ｖの電圧を１６ｐＤＩＰに印加して、断線不良を調べた。１５個のパッケージの内の８個以上に不良が出るまでの時間を不良時間とした。単位は時間。なお測定時間は、最長で５００時間とし、その時点で不良パッケージ数が７個以下であったものは、不良時間を５００時間以上と示した。不良時間が長いほど耐湿信頼性に優れる。
【００３４】
（実施例８〜９、比較例５〜８）
実施例８〜９および比較例５〜８について、表３の配合に従い、実施例７と同様にしてエポキシ樹脂成形材料を調製し評価した。結果を表３に示す。
【００３５】
【表３】

【００３６】
実施例７〜９の本発明のエポキシ樹脂成形材料は、保存性、硬化性がきわめて良好であり、またこのエポキシ樹脂成形材料の硬化物で封止された半導体装置は、耐湿性が良好であることがわかる。一方、比較例５〜８のエポキシ樹脂成形材料は流動性、保存性、耐湿信頼性のいずれかが実施例７〜９と比較し劣る。
【００３７】
【発明の効果】
本発明の熱硬化性樹脂組成物及びエポキシ樹脂成形材料は、優れた硬化性、保存性を有し、これを用いて半導体素子を封止してなる半導体装置は、耐湿信頼性に優れており、産業上有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermosetting resin composition having good curability and storage stability and useful in the field of electric and electronic materials, an epoxy resin molding material using the same, and a semiconductor device.
[0002]
[Prior art]
In recent years, electrical and electronic materials, especially sealing materials for semiconductors, have been required to be fast-curing for the purpose of improving production efficiency and to improve storability for improving handling during distribution and storage. ing.
Conventionally, epoxy resins for the electric and electronic materials field include various curing agents such as amines, imidazole compounds, nitrogen-containing heterocyclic compounds such as diazabicycloundecene, quaternary ammonium, phosphonium or arsonium compounds. These compounds are used.
Although amines, especially imidazoles, exhibit excellent curability, they are a cause of internal wiring corrosion under high-temperature and high-humidity conditions as semiconductor sealing materials, that is, they tend to have low moisture resistance reliability. However, there is a problem with the use of phosphorous compounds such as phosphonium compounds.
These generally used curing catalysts often exhibit a curing accelerating action even at a relatively low temperature such as room temperature. This is a cause of lowering the quality of the resin composition such as an increase in viscosity during production and storage of the resin composition, a decrease in fluidity, and a variation in curability.
[0003]
In order to solve this problem, researches on so-called latent curing accelerators have been actively conducted in recent years, which suppress the change in viscosity and fluidity at low temperatures with time and develop a curing reaction only by heating during molding and molding. Yes. As a means for this, studies have been made to express latency by protecting the active sites of the curing accelerator with ion pairs. JP-A-8-41290 discloses salt structures of various organic acids and phosphonium ions. A latent cure accelerator is disclosed. However, this phosphonium salt does not have a specific high-order molecular structure, and the ion pair is relatively easily affected by the external environment. Therefore, the phosphonium salt is easily moved by molecules such as recent low-molecular epoxy resins and phenol aralkyl resins. In the sealing material for semiconductors using a phenol resin hardening | curing agent, the problem that storage property falls arises.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a thermosetting resin composition having good curability and storage stability and useful in the field of electric and electronic materials, an epoxy resin molding material using the same, and a semiconductor device having excellent moisture resistance reliability. It is what.
[0005]
[Means for Solving the Problems]
The present invention
[1] A compound having two or more epoxy groups in one molecule (A), a compound having two or more phenolic hydroxyl groups in one molecule (B), represented by general formula (1) or general formula (2) An epoxy resin molding material characterized in that the molecular compound (C) and the inorganic filler (D) are essential components, the molecular compound (C) represented by the general formula (1) or the general formula (2) ), The value of m is represented by m = 0 or 0.5, and the phenol component of the general formula (1) is bis (4-hydroxyphenyl) sulfone, 2,2-bis (4-hydroxyphenyl) 1,1, 1-3,3,3-hexafluoropropane, bis (4-hydroxyphenyl) ether, or bis (4-hydroxy-3-methylphenyl) sulfone, and the phenol component of the general formula (2) is 2,3- Dihydroxy Epoxy resin molding material is Futaren,
[Chemical formula 5]

(P is a phosphorus atom, R ₁ , R ₂ , R ₃ and R ₄ are substituted or unsubstituted aromatic groups, or alkyl groups, A ₁ is a divalent aromatic group, B ₁ is a single bond or an ether group, A divalent substituent selected from a sulfone group, a sulfide group, and a carbonyl group or a divalent organic group composed of 1 to 13 carbon atoms is represented, m represents a number of 0 ≦ m <1.
[0006]
[Chemical 6]

(P is a phosphorus atom, R ₁ , R ₂ , R ₃ and R ₄ are substituted or unsubstituted aromatic groups or alkyl groups, and A ₂ is a divalent aromatic group. M is 0 ≦ m <1. Indicates the number of
[0009]
[2] A semiconductor device comprising a semiconductor element sealed with the epoxy resin molding material according to item [1],
It is.
By using these, an epoxy resin molding material having extremely good curability and storage stability can be obtained.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The compound (A) having two or more epoxy groups in one molecule used in the present invention is not limited as long as it has two or more epoxy groups in one molecule. For example, biphenyl type epoxy resin, novolak type Examples thereof include phenols such as biphenol such as epoxy resin and naphthalene type epoxy resin, epoxy resins obtained by reacting epichlorohydrin with hydroxyl groups such as phenol resins and naphthols, and epoxy compounds. Other examples include epoxy resins obtained by oxidizing an olefin with a peracid to epoxidize such as alicyclic epoxy resins, and those obtained by epoxidizing dihydroxybenzenes such as hydroquinone with epichlorohydrin.
[0011]
Further, the compound (B) having two or more phenolic hydroxyl groups in one molecule acts as a curing agent for the compound (A) having two or more epoxy groups in one molecule. Specifically, phenol novolak resins, cresol novolak resins, alkyl-modified novolak resins (including resins obtained by reacting and co-condensing cycloalkene double bonds with Friedel-Crafts-type reactions), phenol aralkyl resins, naphthols Examples thereof include resins obtained by co-condensation of phenol and phenol with a carbonyl group-containing compound, as long as two or more hydrogen atoms bonded to an aromatic ring in one molecule are substituted with a hydroxyl group.
[0012]
The molecular compound (C) acting as a curing accelerator in the present invention is represented by the general formula (1) or the general formula (2) and is a molecular aggregate of a tetra-substituted phosphonium and a phenol compound. Consists of one tetra-substituted phosphonium cation, one or more and less than three phenolic hydroxyl groups and one phenoxide anion unit, and one or more and less than three phenolic groups around the positive charge of the tetra-substituted phosphonium ion It is considered that the hydroxyl group and one phenoxide anion surround and are a stabilized structure.
[0013]
As the phosphonium ion capable of taking such a structure, a tetra-substituted phosphonium ion having a substituted or unsubstituted aryl group or alkyl group as a substituent is preferable because it is stable against heat and hydrolysis. Examples include tetraaryl substituted phosphoniums such as phosphonium and tetratolylphosphonium, triaryl monoalkylphosphoniums synthesized from triarylphosphines such as triphenylmethylphosnium and alkyl halides, and tetraalkyl substituted phosphoniums such as tetrabutylphosphonium.
[0014]
Moreover, as a phenol compound which is another component which forms molecular compound (C), bisphenol A (2,2-bis (4-hydroxyphenyl) propane), bisphenol F (4,4'-methylene bisphenol, 2 , 4'-methylenebisphenol, 2,2-methylenebisphenol), bis (4-hydroxyphenyl) sulfone (bisphenol S), bisphenol E (4,4'-ethylidenebisphenol), bisphenol fluorene (4,4 '-(9H -Fluorene-9-ylidene) bisphenol), 4,4'-methylidenebis (2,6-dimethylphenol), bisphenols such as bis (4-hydroxyphenyl) methanone, 4,4'-biphenol, 2,2'- Biphenol, 3,3 ', 5,5'-tetramethylbipheno 2,2-bis (4-hydroxyphenyl) 1,1,1-3,3,3-hexafluoropropane and other biphenols, hydroquinone, resorcinol, catechol, bis (4-hydroxyphenyl) ether, 2,6 -Dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,1′-bi-2-naphthol, 1,4-dihydroxyanthraquinone, etc. Bisphenol A, bisphenol F (4,4'-methylenebisphenol, 2,4'-methylenebisphenol, 2,2'-methylenebisphenol, Honshu Chemical Industry ( (Including a mixture of these isomers such as bisphenol F-D), bis Enol S, 4,4′-biphenol, 2,2-bis (4-hydroxyphenyl) 1,1,1-3,3,3-hexafluoropropane, bis (4-hydroxyphenyl) ether 2,3-dihydroxy Naphthalene is preferred.
[0015]
The molecular compound (C) includes a phenol compound as described above and a base that finally assists dehydrohalogenation, such as alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and organic bases such as pyridine and triethylamine. Dissolving in a solvent such as alcohol, and subsequently adding and reacting the tetra-substituted phosphonium halide dissolved in an appropriate solvent, and finally removing it as a solid by recrystallization or reprecipitation, It can be synthesized by a method in which a substituted phosphonium tetrasubstituted borate and a phenol compound are subjected to a heat reaction and then heated in a solvent such as alcohol.
[0016]
The molecular compound (C) used in the present invention has a phosphonium-phenoxide type salt in the structure as described above, but this is different from the conventional phosphonium-organic acid anion salt type compound in the molecular compound (C). The higher-order structure by the hydrogen bond involving the proton of the phenolic hydroxyl group surrounds this ionic bond. In the conventional salt, the reactivity is controlled only by the strength of the ionic bond, whereas in the molecular compound (C), the ion pair of the reaction active site is surrounded by a higher-order structure at room temperature, and the active site is On the other hand, in the actual molding stage, the higher-order structure is broken, so that the active sites are exposed, and so-called latency is exhibited that expresses reactivity.
[0017]
The compounding amount of the molecular compound (C) acting as a curing accelerator used in the present invention is 2 (2) phenolic hydroxyl groups in one molecule acting as a compound (A) having two or more epoxy groups in one molecule and a curing agent. When the total weight of the compound (B) having at least one is 100 parts by weight, about 0.5 to 20 parts by weight is preferable because the balance between curability, storage stability and other characteristics is good. The compounding ratio of the compound (A) having two or more epoxy groups in one molecule and the compound (B) having two or more phenolic hydroxyl groups in one molecule is a compound having two or more epoxy groups in one molecule. The total of the phenolic hydroxyl group of the compound (B) having two or more phenolic hydroxyl groups in one molecule and the phenolic hydroxyl group contained in the molecular compound (C) is 0. When it is used so as to have a molar ratio of about 5 to 2 mol, preferably about 0.8 to 1.2, the curability, heat resistance, electrical properties and the like become better.
[0018]
There is no restriction | limiting in particular about the kind of inorganic filler (D) used for this invention, Generally what is used for the sealing material can be used. Examples thereof include fused crushed silica powder, fused spherical silica powder, crystalline silica powder, secondary agglomerated silica powder, alumina, titanium white, aluminum hydroxide, talc, clay, glass fiber and the like, and fused spherical silica powder is particularly preferable. The shape is preferably infinitely spherical, and the amount of filling can be increased by mixing particles having different particle sizes.
[0019]
As a blending amount of the inorganic filler, per 100 parts by weight of the total amount of the compound (A) having two or more epoxy groups in one molecule and the compound (B) having two or more phenolic hydroxyl groups in one molecule, 200 to 2400 parts by weight are preferred. If the amount is less than 200 parts by weight, the reinforcing effect of the inorganic filler may not be sufficiently exhibited. If the amount exceeds 2400 parts by weight, the fluidity of the molding material is lowered, and there is a risk of filling failure during molding, such being undesirable. In particular, if the blending amount of the inorganic filler is 250 to 1400 parts by weight per 100 parts by weight of the total amount of the components (A) and (B), the moisture absorption rate of the cured product of the molding material is reduced, and solder cracks are reduced. Since generation | occurrence | production can be prevented and the viscosity of the molding material at the time of a fusion | melting becomes low, there is no possibility of causing a gold wire deformation | transformation inside a semiconductor device, and it is more preferable. The inorganic filler is preferably mixed well in advance.
[0020]
In addition to the components (A) to (D), the epoxy resin molding material of the present invention includes a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a colorant such as carbon black, and a brominated epoxy as necessary. Various additives such as resins, antimony oxide, flame retardants such as phosphorus compounds, low stress components such as silicone oil and silicone rubber, natural waxes, synthetic waxes, higher fatty acids or metal salts thereof, mold release agents such as paraffin, antioxidants, etc. In the present invention, triphenylphosphine, 1,8-diazabicyclo (5,4,0) undecene- is used as long as the properties of the molecular compound (C) that functions as a curing accelerator in the present invention are not impaired. There is no problem even if it is used in combination with a catalyst such as 7,2-methylimidazole.
[0021]
The epoxy resin molding material of the present invention is obtained by mixing components (A) to (D) and other additives at room temperature using a mixer, kneading with a kneader such as a roll or an extruder, and pulverizing after cooling. It is done.
In order to seal an electronic component such as a semiconductor and manufacture a semiconductor device by using the epoxy resin molding material of the present invention, it can be cured and molded by a molding method such as transfer molding, compression molding, or injection molding.
A semiconductor device sealed with a cured product of the epoxy resin molding material of the present invention is included in the technical scope of the present invention and exhibits excellent moisture resistance.
[0022]
【Example】
Examples of the present invention will be shown below, but the present invention is not limited thereby.
[Synthesis of curing accelerator]
Hereinafter, the structure of the synthesized molecular compound (C) was confirmed by NMR, elemental analysis, and neutralization titration (measurement of phosphonium phenoxide equivalent) by the following method.
The synthesized molecular compound (C) is reacted with an excess amount of oxalic acid with a known weight in a methanol / water solvent, and the remaining oxalic acid is quantified with an aqueous sodium hydroxide solution with a known normality to obtain the molecular compound (C). The normality per weight (N / g) was calculated. The reciprocal of this value is the phosphonium phenoxide equivalent.
[0023]
(Synthesis Example 1)
In a 1-liter separable flask equipped with a stirrer, 37.5 g (0.15 mol) of BPS-N (mainly composed of 4,4′-bisphenol S) manufactured by Nikka Chemical Co., Ltd. and 100 ml of methanol The solution was stirred and dissolved at room temperature, and a solution prepared by previously dissolving 4.0 g (0.1 mol) of sodium hydroxide in 50 ml of methanol was added with further stirring. Next, a solution prepared by previously dissolving 41.9 g (0.1 mol) of tetraphenylphosphonium bromide in 150 ml of methanol was added. After stirring for a while and adding 300 ml of methanol, the solution in the flask was added dropwise to a large amount of water with stirring to obtain a white precipitate. The precipitate was filtered and dried to obtain 66.0 g of white crystals. This compound is designated as C1. C1 is a target molecular compound in which one molecule of tetraphenylphosphonium and 4,4′-bisphenol S are complexed at a molar ratio of 1: 1.5 from the results of NMR, maspectrum and elemental analysis. It was done. Further, from the value of neutralization titration, the phosphonium phenoxide equivalent was close to the theoretical value 713, indicating the above-mentioned structure. The synthesis yield was 92.6%.
(Synthesis Examples 2 to 6)
In Synthesis Examples 2 to 6, under the conditions shown in Table 1, all basic operations were performed in the same manner as in Synthesis Example 1 to prepare compounds C2 to C6, respectively. The results are shown in Table 1.
[0024]
(Comparative Synthesis Example 1)
A 1 liter separable flask equipped with a stirrer is charged with 12.8 g (0.05 mol) of bis (4-hydroxy-3,5-dimethylphenyl) methane and 50 ml of methanol, dissolved by stirring at room temperature, and further stirred. While adding 4.0 g (0.1 mol) of sodium hydroxide in advance with 50 ml of methanol, a solution was added. Next, a solution prepared by previously dissolving 33.9 g (0.1 mol) of tetrabutylphosphonium bromide in 150 ml of methanol was added. Stirring was continued for a while, 100 ml of pure water was dropped into the flask while stirring, and further 100 ml of 2-propanol was added to obtain a white precipitate. The precipitate was filtered and dried to obtain white crystals. This compound is designated as D1. As a result of conducting the same analysis as in Synthesis Example 1, one molecule of tetrabutylphosphonium is present in each phenoxide in which protons of two hydroxyl groups of bis (4-hydroxy-3,5-dimethylphenyl) methane are dissociated. The compound was ion-bonded at 1: 2. This D1 is merely a phosphonium salt, not a molecular compound used in the present invention.
[0025]
(Comparative Synthesis Example 2)
In a 1 liter separable flask equipped with a stirrer, 17.0 g (0.1 mol) of p-phenylphenol and 50 ml of methanol were charged and stirred and dissolved at room temperature. Mol) was previously dissolved in 50 ml of methanol. Next, a solution prepared by previously dissolving 41.9 g (0.1 mol) of tetraphenylphosphonium bromide in 150 ml of methanol was added. Stirring was continued for a while, 100 ml of pure water was dropped into the flask while stirring, and further 100 ml of 2-propanol was added to obtain a white precipitate. The precipitate was filtered and dried to obtain white crystals. This compound is designated as D2. As a result of conducting the same analysis as in Synthesis Example 1, it was a compound in which one molecule of tetraphenylphosphonium was ion-bonded 1: 1 with phenoxide from which the proton of the hydroxyl group of p-phenylphenol was eliminated. This D2 is merely a phosphonium salt, not a molecular compound used in the present invention.
[0026]
(Comparative Synthesis Example 3)
In a 1 liter separable flask equipped with a stirrer, 12.2 g (0.1 mol) of benzoic acid and 50 ml of methanol were charged and dissolved by stirring at room temperature, and 4.0 g (0.1 mol) of sodium hydroxide was added while stirring. A solution previously dissolved in 50 ml of methanol was added. Next, a solution prepared by previously dissolving 41.9 g (0.1 mol) of tetraphenylphosphonium bromide in 150 ml of methanol was added. Stirring was continued for a while, and the solution in the flask was added dropwise to 100 ml of water while stirring. Further, 100 ml of 2-propanol was added to obtain a white precipitate. The precipitate was filtered and dried to obtain white crystals. This compound is designated as D3. As a result of performing the same analysis as in Synthesis Example 1, it was a compound in which one molecule of tetraphenylphosphonium was ion-bonded 1: 1 with the carboxylate from which the proton of the carboxyl group of benzoic acid was eliminated. This D3 is merely a phosphonium salt, not a molecular compound used in the present invention.
The results of the comparative synthesis examples are also summarized in Table 1 as with the other synthesis examples.
[0027]
[Table 1]

[0028]
[Evaluation of thermosetting resin composition]
First, the synthesized molecular compound (C) is pulverized and mixed with a compound (A) having two or more epoxy groups in one molecule and a compound (B) having two or more phenolic hydroxyl groups in one molecule. Further, after melt-kneading on a hot plate at 100 ° C. for 5 minutes, a sample of the composition was prepared by cooling and pulverizing and evaluated. The evaluation method is as follows.
(1) Curing torque Using the composition prepared by the above-described sample preparation method, a torque after 45 seconds was obtained at 175 ° C. with a curast meter (manufactured by Orientec Co., Ltd., JSR curast meter PS type). . The torque in the curast meter is a parameter of curability, and the larger this value, the better the curability. The unit is kgf · cm.
(2) Curing heat generation residual rate (preservation evaluation)
Using the composition prepared by the above sample preparation method, the initial curing calorific value immediately after the preparation and the curing calorific value after storage treatment at 40 ° C. for 3 days are measured, and the storage treatment with respect to the initial curing calorific value (mJ / mg). The percentage of the subsequent heating value (mJ / mg) was calculated. The amount of heat generated by curing was measured by differential thermal analysis at a temperature increase rate of 10 ° C./min. The larger this value, the better the storage stability.
[0029]
(Examples 1-6 and Comparative Examples 1-4)
About Examples 1-6 and Comparative Examples 1-4, the sample of the composition was prepared and evaluated by the above-mentioned method according to the formulation shown in Table 2. In Comparative Example 1, triphenylphosphine was used instead of Compound (C) in Examples, and in Comparative Examples 2 to 4, Compounds D1 to D3 synthesized in Comparative Synthesis Examples 1 to 3 were used. The evaluation results of the obtained compositions were as shown in Table 2.
[0030]
[Table 2]

[0031]
As shown in the examples, the thermosetting resin composition of the present invention has good curability and storage stability, whereas the resin composition using the triphenylphosphine of Comparative Example 1 as a curing accelerator, The phosphonium salt which is not a molecular compound used in the present invention of Comparative Examples 2 to 4 is inferior in preservability although it is good in curability and preservability.
[0032]

Were mixed using a hot roll at 95 ° C. for 8 minutes, cooled and pulverized to obtain an epoxy resin molding material. The obtained epoxy resin molding material was evaluated by the following methods. The results are shown in Table 3.
[0033]
Evaluation Method (1) The spiral flow was measured at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 2 minutes, using a mold for spiral flow measurement according to EMMI-I-66. The spiral flow is a parameter of fluidity, and a larger value indicates better fluidity. The unit is cm.
(2) Curing torque was measured using a curast meter (Orientec Co., Ltd., JSR curast meter IVPS type) at 175 ° C. for 45 seconds. The larger this value, the better the curability. The unit is kgf · cm
(3) The flow residual ratio was expressed as a percentage after storage with respect to the spiral flow immediately after the preparation and after measuring the spiral flow after storage at 30 ° C. for 1 week. Units%.
(4) Moisture resistance reliability was determined by molding 16 pDIP at a mold temperature of 175 ° C., a pressure of 70 kg / cm ² , a curing time of 2 minutes, and post-curing the molded product for 8 hours at 175 ° C. In a water vapor with a relative humidity of 100%, a voltage of 20 V was applied to 16 pDIP, and the disconnection failure was examined. The time until a defect appears in 8 or more of the 15 packages was defined as a defect time. The unit is time. The measurement time was 500 hours at the longest, and when the number of defective packages was 7 or less at that time, the defective time was 500 hours or more. The longer the defect time, the better the moisture resistance reliability.
[0034]
(Examples 8-9, Comparative Examples 5-8)
With respect to Examples 8 to 9 and Comparative Examples 5 to 8, epoxy resin molding materials were prepared and evaluated in the same manner as in Example 7 according to the formulations shown in Table 3. The results are shown in Table 3.
[0035]
[Table 3]

[0036]
The epoxy resin molding materials of Examples 7 to 9 of the present invention have extremely good storage stability and curability, and the semiconductor device sealed with a cured product of this epoxy resin molding material has good moisture resistance. I understand that. On the other hand, the epoxy resin molding materials of Comparative Examples 5 to 8 are inferior to those of Examples 7 to 9 in terms of fluidity, storage stability, and moisture resistance reliability.
[0037]
【The invention's effect】
The thermosetting resin composition and the epoxy resin molding material of the present invention have excellent curability and storage stability, and a semiconductor device formed by sealing a semiconductor element using this has excellent moisture resistance reliability. , Industrially useful.

Claims (2)

Compound (A) having two or more epoxy groups in one molecule, compound (B) having two or more phenolic hydroxyl groups in one molecule, molecular compound represented by general formula (1) or general formula (2) An epoxy resin molding material comprising (C) and an inorganic filler (D) as essential components, wherein m in the molecular compound (C) represented by the general formula (1) or the general formula (2) In which m = 0 or 0.5, the phenol component of the general formula (1) is bis (4-hydroxyphenyl) sulfone, 2,2-bis (4-hydroxyphenyl) 1,1,1-3 , 3,3-hexafluoropropane, bis (4-hydroxyphenyl) ether, or bis (4-hydroxy-3-methylphenyl) sulfone, and the phenol component of the general formula (2) is 2,3-dihydroxynaphtha Epoxy resin molding material is down.

(P is a phosphorus atom, R ₁ , R ₂ , R ₃ and R ₄ are substituted or unsubstituted aromatic groups, or alkyl groups, A ₁ is a divalent aromatic group, B ₁ is a single bond or an ether group, A divalent substituent selected from a sulfone group, a sulfide group, and a carbonyl group or a divalent organic group composed of 1 to 13 carbon atoms is represented, m represents a number of 0 ≦ m <1.

(P is a phosphorus atom, R ₁ , R ₂ , R ₃ and R ₄ are substituted or unsubstituted aromatic groups, or alkyl groups, and A ₂ is a divalent aromatic group. Number of 0 ≦ m <1 Is shown.)   A semiconductor device comprising a semiconductor element sealed with the epoxy resin molding material according to claim 1.