JP4258690B2 - Photosensitive resin composition - Google Patents

Description

（ただし、式中、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴の少なくとも１つはフラン、チオフェン又はピロール構造であるcis−ジエン構造を有する１価の有機基であり、残余は、それぞれ独立に水素、ヒドロキシル基、カルボキシル基、炭素数１〜２０のアルキル基又は炭素数１〜２０のアルコキシル基であり、Ｘ¹及びＸ²はそれぞれ独立に酸素、硫黄又は炭素数１〜４の置換基を有していてもよいアルキレン基若しくはアルキレンオキシ基であり、Ａｒ¹及びＡｒ²はそれぞれ独立に２価の芳香族基であり、ｌ₁、ｌ₂、ｍ₁及びｍ₂はそれぞれ独立に０又は１である。ただし、ｌ₁が１のときはｍ₁も１であり、ｌ₂が１のときはｍ₂も１である。）、
（２）一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドと酸素増感剤とを含有することを特徴とする感光性樹脂組成物、
【化４】

（ただし、式中、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹及びＲ¹²の少なくとも１つはフラン、チオフェン又はピロール構造であるcis−ジエン構造を有する１価の有機基であり、残余は、それぞれ独立に水素、ヒドロキシル基、カルボキシル基、炭素数１〜２０のアルキル基又は炭素数１〜２０のアルコキシル基であり、Ｙ¹は酸素、硫黄又は炭素数１〜４の置換基を有していてもよいアルキレン基、アルキリデン基若しくはアルキレンオキシ基であり、ｎ₁は０又は１である。）、及び、
（３）酸素増感剤が、フラーレンである第(１)項又は第(２)項記載の感光性樹脂組成物、
を提供するものである。
【０００５】
【発明の実施の形態】
本発明の感光性樹脂組成物の第１の形態は、一般式［１］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドと酸素増感剤とを含有するものである。
【化５】

ただし、一般式［１］において、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴の少なくとも１つはcis−ジエン構造を有する１価の有機基であり、残余は、それぞれ独立に水素、ヒドロキシル基、カルボキシル基、炭素数１〜２０のアルキル基又は炭素数１〜２０のアルコキシル基であり、Ｘ¹及びＸ²はそれぞれ独立に酸素、硫黄又は炭素数１〜４の置換基を有していてもよいアルキレン基若しくはアルキレンオキシ基であり、Ａｒ¹及びＡｒ²は、それぞれ独立に２価の芳香族基であり、ｌ₁、ｌ₂、ｍ₁及びｍ₂は、それぞれ独立に０又は１である。ただし、ｌ₁が１のときはｍ₁も１であり、ｌ₂が１のときはｍ₂も１である。
【０００６】
本発明の感光性樹脂組成物の第２の形態は、一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドと酸素増感剤を含有するものである。
【化６】

ただし、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹及びＲ¹²の少なくとも１つはcis−ジエン構造を有する１価の有機基であり、残余は、それぞれ独立に水素、ヒドロキシル基、カルボキシル基、炭素数１〜２０のアルキル基又は炭素数１〜２０のアルコキシル基であり、Ｙ¹は酸素、硫黄又は炭素数１〜４の置換基を有していてもよいアルキレン基、アルキリデン基若しくはアルキレンオキシ基であり、ｎ₁は０又は１である。なお、水素を置換するハロゲンなどの原子も置換基である。
本発明組成物において、一般式［１］又は一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドは、cis−ジエン構造を有する１価の有機基で置換された芳香環のメタ位に主鎖が結合していることが特徴である。芳香環のパラ位に主鎖が結合していると、ポリアミック酸又はポリイミドの結晶性などの分子パッキングが増大する傾向にあり、特にcis−ジエン構造が導入された状態での現像液への溶解性が低下してしまう。その結果、光パターン作成時に、本来現像液に溶解されるべき未露光部と、光架橋された露光部との現像液に対する溶解速度の差が発現しにくくなり、コントラスト発現のために大量の露光が必要となる、良好な形状の樹脂パターンが得られにくい、未露光部の樹脂が完全に除去しにくいなど、パターン形成能が大きく低下してしまうおそれがある。本発明組成物のように、cis−ジエン構造を有する１価の有機基で置換された芳香環のメタ位に主鎖への結合を存在させれば、対応するポリアミック酸及びポリイミドの現像液に対する溶解性が向上し、その結果露光部と未露光部のコントラストが明確となり、光パターニング性が向上するものである。
【０００７】
本発明組成物において、一般式［１］又は一般式［２］で表される構造単位は、ポリアミック酸又はポリイミド中に１種のみが存在してもよく、２種以上が共重合単位として存在してもよい。本発明組成物において、一般式［１］又は一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドは、１種のみが含有されていてもよく、２種以上が混合して含有されていてもよい。また、本発明組成物は、一般式［１］又は一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドと、一般式［１］又は一般式［２］で表される構造単位を有しないポリアミック酸又はポリイミドとの混合物とすることもできる。
一般式［１］及び一般式［２］において、cis−ジエン構造を有する１価の有機基としては、例えば、−ＣＨ₂Ｏ−ＣＯ−Ｄ、−Ｏ−ＣＯ−Ｄ、−ＣＯ−Ｏ−ＣＨ₂−Ｄ、−ＣＨ₂Ｏ−ＣＨ₂−Ｄ、−Ｏ−ＣＨ₂−Ｄ、−ＮＨ−ＣＯ−Ｄ、−ＣＯ−ＮＨ−ＣＨ₂−Ｄなどを挙げることができる。ただし、Ｄは、cis−ジエン構造である。Ｄで表されるcis−ジエン構造としては、例えば、シクロペンタジエニル基、フリル基、ピロリル基、チエニル基、ピラニル基、イソベンゾフラニル基、インドリジニル基、キノリジニル基などを挙げることができる。これらの中で、シクロペンタジエニル基、フリル基、ピロリル基及びチエニル基が特に好ましい。
一般式［１］及び一般式［２］において、炭素数１〜２０のアルキル基としては、例えば、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、デシル基、ラウリル基などを挙げることができる。これらの中で、メチル基、エチル基、ブチル基及びペンチル基が特に好ましい。
一般式［１］及び一般式［２］において、炭素数１〜２０のアルコキシル基としては、例えば、メトキシ基、エトキシ基、ブトキシ基、ペンチルオキシ基、ヘキシルオキシ基、ラウリルオキシ基、イソプロピルオキシ基などを挙げることができる。これらの中で、メトキシ基、エトキシ基、ブトキシ基及びペンチルオキシ基が特に好ましい。
【０００８】
これらの官能基を有する一般式［１］で表される構造単位の例としては、下記の式［１−(１)］〜［１−(２０)］で表される構造単位を挙げることができ、一般式［２］で表される構造単位の例としては、式［２−(１)］〜［２−(１０)］で表される構造単位を挙げることができる。
【化７】

【化８】

【化９】

【化１０】

【化１１】

本発明組成物に用いる一般式［１］又は一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドの製造方法に特に制限はなく、例えば、ヒドロキシル基を有するジアミンとポリカルボン酸二無水物を反応したのち、cis−ジエン構造を有する１価の有機基を導入することができ、あるいは、cis−ジエン構造を有する１価の有機基を有するジアミンとポリカルボン酸二無水物を反応することもできる。
本発明において、ジアミンと反応させるポリカルボン酸二無水物に特に制限はなく、例えば、ピロメリット酸二無水物、３,３',４,４'−ベンゾフェノンテトラカルボン酸二無水物、３,３',４,４'−ビフェニルテトラカルボン酸二無水物、４,４'−ヘキサフルオロイソプロピリデン二フタル酸無水物などを挙げることができる。これらの中で、４,４'−ヘキサフルオロイソプロピリデン二フタル酸無水物を特に好適に用いることができる。
【０００９】
cis−ジエン構造を有する１価の有機基を有しないジアミンとポリカルボン酸二無水物とを重合して得られるポリアミック酸又はポリイミドにcis−ジエン構造を有する１価の有機基を導入する場合、一般式［３］又は一般式［４］で表されるジアミンとポリカルボン酸二無水物を出発原料とすることができる。
【化１２】

ただし、一般式［３］において、Ｒ¹³、Ｒ¹⁴、Ｒ¹⁵、Ｒ¹⁶の少なくとも１つはヒドロキシル基、ヒドロキシメチル基又はカルボキシル基であり、残余は、それぞれ独立に水素、炭素数１〜２０のアルキル基又は炭素数１〜２０のアルコキシル基であり、Ｘ³及びＸ⁴はそれぞれ独立に酸素、硫黄又は炭素数１〜４の置換基を有していてもよいアルキレン基若しくはアルキレンオキシ基であり、Ａｒ³及びＡｒ⁴はそれぞれ独立に２価の芳香族基であり、ｌ₃、ｌ₄、ｍ₃及びｍ₄はそれぞれ独立に０又は１である。ただし、ｌ₃が１のときはｍ₃も１であり、ｌ₄が１のときはｍ₄も１である。一般式［４］において、Ｒ¹⁷、Ｒ¹⁸、Ｒ¹⁹、Ｒ²⁰、Ｒ²¹、Ｒ²²、Ｒ²³及びＲ²⁴の少なくとも１つはヒドロキシル基、ヒドロキシメチル基又はカルボキシル基であり、残余は、それぞれ独立に水素、炭素数１〜２０のアルキル基又は炭素数１〜２０のアルコキシル基であり、Ｙ²は酸素、硫黄又は炭素数１〜４の置換基を有していてもよいアルキレン基，アルキリデン基若しくはアルキレンオキシ基であり、ｎ₂は０又は１である。なお、水素を置換するハロゲンなどの原子も置換基である。
一般式［３］で表されるジアミンとしては、例えば、３,５−ジアミノベンジルアルコール、３,５−ジアミノフェノール、３,５−ジアミノ安息香酸などを挙げることができる。一般式［４］で表されるジアミンとしては、例えば、３,３'−ジアミノ−４,４'−ジヒドロキシビフェニル、２,２−ビス(３−アミノ−４−ヒドロキシフェニル)ヘキサフルオロプロパン、３,５−ビス(４−アミノフェノキシ)ベンジルアルコールなどを挙げることができる。
【００１０】
本発明において、一般式［３］又は一般式［４］で表されるジアミンとポリカルボン酸二無水物を反応させる方法に特に制限はなく、公知の重合法によりポリアミック酸を合成することができる。例えば、一般式［３］で表されるジアミンとピロメリット酸二無水物をＮ−メチル−２−ピロリドンなどの溶媒中において反応させることにより、一般式［５］で表される構造単位を有するポリアミック酸を得ることができる。さらに、一般式［５］で表される構造単位を有するポリアミック酸を脱水閉環反応することにより、一般式［６］で表される構造単位を有するポリイミドを得ることができる。
【化１３】

一般式［５］で表される構造単位を有するポリアミック酸又は一般式［６］で表される構造単位を有するポリイミドに、cis−ジエン構造を有する１価の有機基を導入する方法に特に制限はなく、例えば、cis−ジエン構造を有するハロゲン化物を塩基の存在下に反応させることにより、一般式［５］で表される構造単位を有するポリアミック酸又は一般式［６］で表される構造単位を有するポリイミドのヒドロキシル基にcis−ジエン構造を有する１価の有機基を導入することができる。一般式［５］においてＲ¹⁵がヒドロキシル基であり、cis−ジエン構造を有するハロゲン化物がフルフリルブロミドである場合には、一般式［７］で表される構造単位を有するポリアミック酸が得られる。
【化１４】

【００１１】
本発明において、cis−ジエン構造を有する１価の有機基を有するジアミンとポリカルボン酸二無水物の反応により、ポリアミック酸又はポリイミドを合成する場合、用いることのできるcis−ジエン構造を有する１価の有機基を有するジアミンとしては、例えば、３,５−ジアミノベンジル−２−フロエート、１,１,１,３,３,３−ヘキサフルオロ−２,２−ビス(４−フルフリルオキシ−３−アミノフェニル)プロパン、３,３'−ジアミノ−４,４'−ジ(２−フロイルアミノ)ビフェニル、４,４'−ジフルフリルオキシ−３,３'−ジアミノビフェニルなどを挙げることができる。これらのジアミンは、例えば、ヒドロキシル基、カルボキシル基又はヒドロキシアルキル基を有する芳香族ジニトロ化合物にフルフリルブロミドなどのcis−ジエン構造を有するハロゲン化物を塩基の存在下に反応させ、引き続いてニトロ基を還元する方法などによって得ることができる。ニトロ基の還元方法に特に制限はなく、例えば、ヒドラジンによる還元、ニッケル、パラジウム、白金などの遷移金属触媒存在下での接触水素化反応、インジウム−塩化アンモニウム水溶液による還元などを挙げることができる。
本発明に用いられる一般式［１］又は一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドは、溶剤又はアルカリ水溶液に可溶性である。このポリアミック酸又はポリイミドは、酸素増感剤の作用で発生する一重項酸素と容易に反応し、過酸基を有するポリアミック酸又はポリイミドの中間体を形成する。この中間体は、直ちに、隣接するポリアミック酸又はポリイミドと反応し、互いに重縮合反応により架橋し、分子量を飛躍的に増大させる。これにより、ポリアミック酸又はポリイミドは不溶性となる。さらに、重縮合反応によって架橋したポリアミック酸又はポリイミドの耐熱性は飛躍的に増大する。本発明の感光性樹脂組成物は、従来の感光性ポリイミドとは異なり、光ラジカル重合によらず、cis−ジエン構造を一重項酸素により重縮合することによって架橋させるので、空気中の酸素によって反応が阻害されることがなく、得られる架橋樹脂の耐熱性が優れている。
【００１２】
本発明において、一般式［１］又は一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミドの分子量は、５,０００以上であることが好ましく、１０,０００〜１,０００,０００であることがより好ましく、５０,０００〜２００,０００であることがさらに好ましい。ポリアミック酸又はポリイミドの分子量が小さすぎると、均一な膜を得ることが困難になるおそれがある。ポリアミック酸又はポリイミドの分子量が大きすぎると、溶解性が低下し、均一に成膜することが困難になるおそれがある。
本発明組成物に用いる酸素増感剤に特に制限はないが、励起三重項エネルギーが２２.５キロカロリー／モル以上の酸素増感剤であることが好ましい。このような酸素増感剤としては、例えば、メチレンブルー、ローズベンガル、ヘマトポルフィリン、テトラフェニルポルフィン、ルブレン、フラーレンＣ６０、フラーレンＣ７０、フラーレンＣ８２などを挙げることができる。これらの酸素増感剤は、１種を単独で用いることができ、あるいは、２種以上を組み合わせて用いることもできる。これらの中で、フラーレンＣ６０及びフラーレンＣ７０を特に好適に用いることができる。
本発明組成物において、酸素増感剤の配合量に特に制限はないが、一般式［１］又は一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸又はポリイミド１００重量部当たり０.０１〜２０重量部であることが好ましく、０.１〜１０重量部であることがより好ましい。酸素増感剤の配合量が少なすぎると、増感効果が不十分となるおそれがある。酸素増感剤の配合量が多すぎると、経済的に不利となるのみならず、均一な製膜が困難となるおそれがある。高分子量のcis−ジエン置換ポリアミック酸又はポリイミドと酸素増感剤を含有する本発明組成物は、溶液として用いるとき適度な粘度を有し、スピンコートによりシリコンウエハー上に必要な膜厚を保って均一に塗布することができる。また、組成物中の高分子量のcis−ジエン置換ポリアミック酸又はポリイミドの架橋により被膜が形成されるので、その被膜は強度と耐熱性に優れている。また、フラーレンなどの高価な酸素増感剤の使用は比較的少量なので、経済的に有利に製造することができる。
【００１３】
本発明の感光性樹脂組成物の使用方法に特に制限はないが、一般的には、基材・サブストレート上に塗膜を形成し、露光・現像によるパターン加工を行ったのち、必要に応じて、さらに熱硬化を行い樹脂層を形成する。塗膜の形成方法に特に制限はなく、例えば、感光性樹脂組成物を溶剤に溶解して得られるワニスを、基材・サブストレート上に直接スピンコート法などにより塗布したのち温和な条件で乾燥する方法、あるいは、溶剤に溶解して得られるワニスを予めプラスティックシートやステンレスなどの金属などからなる離型基材に塗布し、温和な条件で乾燥して得られるコーティングを、基材・サブストレート上に加圧ラミネートして転写する方法などを挙げることができる。
本発明組成物の露光に使用する光の波長は、使用する酸素増感剤に応じて適宜選択することができる。例えば、フラーレンＣ６０を増感剤として使用する場合、紫外域〜可視光域の広範な波長域（２５０〜７８０ｎｍ）の光を使用することができる。露光は、形成した樹脂層の中で樹脂を除去したい部分を遮光することができるマスクを介して、光を樹脂層上に照射することにより行うことができる。露光後の現像は、未露光の樹脂組成物を溶解する有機溶剤又はアルカリ水溶液を用いて行うことができる。露光部の樹脂は反応により不溶化するが、未露光部の樹脂は溶解し、その結果マスクにより樹脂に孔などのパターン加工を行うことができる。
一般式［１］又は一般式［２］で表される構造単位を有するcis−ジエン置換ポリアミック酸は、現像後熱硬化を行い、脱水閉環反応によりポリアミック酸をポリイミドに変換することができる。熱硬化反応の条件に特に制限はないが、通常は１５０〜２５０℃で３０分以上加熱することが好ましい。加熱は、熱風、赤外線照射、熱盤上などで行うことができる。通常は空気雰囲気中で行うことができるが、必要に応じて、窒素、二酸化炭素などの不活性ガス雰囲気、減圧下などで行うこともできる。cis−ジエン置換ポリイミドは、必ずしも熱硬化反応を行う必要はないが、上記温度条件で加熱することにより樹脂に高い熱履歴を与え、耐熱性をより向上させることができる。本発明の樹脂組成物をこれらの加工工程で使用することにより、優れた耐熱性を有するパターン形成された樹脂層が低温における加工で形成され、良好な特性を有する半導体素子、プリント回路配線板などを製造することが可能になる。
【００１４】
【実施例】
以下に、実施例を挙げて本発明をさらに詳細に説明するが、本発明はこれらの実施例によりなんら限定されるものではない。
実施例１
３,３'−ジアミノ−４,４'−ジヒドロキシビフェニル８.４７ｇ（０.０３９２モル）とピロメリット酸無水物８.５５ｇ（０.０３９２モル）をＮ−メチル−２−ピロリドン５０ml中、６０℃で撹拌し、ポリアミック酸の溶液を得た。
一方、テトラヒドロフラン５０mlにフルフリルアルコール５.００ｇ（０.０５１０モル）を溶解し、０℃に保ちながら、三臭化リン４.９０ｇ（０.０１８１モル）を滴下した。約２時間撹拌したのち水を加え、１００mlのエーテルを用いて有機成分を２回抽出した。エーテル層を炭酸水素ナトリウムで洗い、モレキュラシーブ３０ｇを加えて一晩乾燥し、ろ過することによりフルフリルブロミドのエーテル溶液を得た。得られた溶液についてＦＴ−ＩＲ、¹Ｈ−ＮＭＲ及び¹³Ｃ−ＮＭＲによる分析を行い、フルフリルブロミドであることを確認した。
次いで、上記のポリアミック酸の溶液に、Ｎ−メチル−２−ピロリドン１５０mlを加えて希釈し、フルフリルブロミド７.７０ｇを含むエーテル溶液及び炭酸カリウム６.５０ｇを添加し、８０℃で約２時間撹拌した。次に、メタノールを用いて再凝固沈殿処理を行い、沈殿物を真空乾燥することによって、式［２−(１０)］で表される構造単位を有するポリアミック酸１６.３ｇを得た。¹Ｈ−ＮＭＲにより分析したところ、ポリアミック酸中のジアミン構造単位の８０モル％がフルフリル基により置換されていた。また、このポリアミック酸の分子量は約７０,０００であった。
高純度のフラーレンＣ６０［９９.９８重量％、Ｔｅｒｍ社製］０.７５ｇと上記のフルフリル基部分置換ポリアミック酸１０.０ｇを、γ−ブチロラクトン／１,１,２,２−テトラクロロエタン（７０／３０、容量比）５０mlに溶解して均一な溶液とした。この溶液をポアサイズ０.１μｍのフィルターでろ過したのち、シリコンウエハー上にスピンコート法により塗布し、８０℃で１０分間の加熱乾燥を行うことにより膜厚２μｍの薄膜を形成した。この薄膜にフォトマスク（凸版テストチャート）を介して５００Ｗ超高圧水銀灯により露光し、直ちに１０重量％水酸化テトラメチルアンモニウム（ＴＭＡＨ）水溶液に３０秒間浸漬して現像処理を行うことにより、未露光部を完全に溶解除去し、線幅５μｍ以下の樹脂パターンを形成した。
得られた樹脂パターンを、２００℃で１時間加熱することにより樹脂層を形成した。この樹脂層について、室温〜３００℃までの熱重量減少率をＴＧ／ＤＴＡ装置［セイコー電子工業(株)製、ＴＧ／ＤＴＡ２２０型、昇温速度１０℃／分］で測定したところ、０.３重量％であった。
【００１５】
実施例２
２,２−ビス(３−アミノ−４−ヒドロキシフェニル)ヘキサフルオロプロパン１４.３６ｇ（０.０３９２モル）とピロメリット酸二無水物８.５５ｇ（０.０３９２モル）をＮ−メチル−２−ピロリドン５０ml中、６０℃で撹拌し、ポリアミック酸の溶液を得た。
次いで、このポリアミック酸の溶液にＮ−メチル−２−ピロリドン１５０mlを加えて希釈し、フルフリルブロミド７.７０ｇを含むエーテル溶液及び炭酸カリウム６.５０ｇを添加し、８０℃で約２時間撹拌した。次に、メタノールを用いて再凝固沈殿処理を行い、沈殿物を真空乾燥することによって、式［２−(５)］で表される構造単位を有するポリアミック酸２０.３ｇを得た。¹Ｈ−ＮＭＲにより分析したところ、ポリアミック酸中のジアミン構造単位の８０モル％がフルフリル基により置換されていた。また、このポリアミック酸の分子量は約５０,０００であった。
高純度のフラーレンＣ６０［９９.９８重量％、Ｔｅｒｍ社製］０.７５ｇと上記のフルフリル基部分置換ポリアミック酸１０.０ｇをγ−ブチロラクトン／１,１,２,２−テトラクロロエタン（７０／３０、容量比）５０mlに溶解して均一な溶液とした。この溶液をポアサイズ０.１μｍのフィルターでろ過したのち、シリコンウエハー上にスピンコート法により塗布し、８０℃で１０分間の加熱乾燥を行うことにより膜厚２μｍの薄膜を形成した。この薄膜にフォトマスクを介して５００Ｗ超高圧水銀灯により露光し、直ちに１０重量％ＴＭＡＨ水溶液に３０秒間浸漬して現像処理を行うことにより未露光部を完全に溶解除去し、線幅５μｍ以下の樹脂パターンを形成した。
得られた樹脂パターンを、２００℃で１時間加熱することにより樹脂層を形成した。この樹脂層について、実施例１と同様にして、室温〜３００℃までの熱重量減少率をＴＧ／ＤＴＡ装置で測定したところ、０.５重量％であった。
【００１６】
比較例１
ジアミン成分として４,４'−ジアミノ−３,３'−ジヒドロキシビフェニル８.４７ｇ（０.０３９２モル）を用いた以外は、実施例１と同様にしてフルフリル基で部分置換されたポリアミック酸を合成した。¹Ｈ−ＮＭＲにより分析したところ、ポリアミック酸中のジアミン構造単位の８５モル％がフルフリル基により置換されていた。また、このポリアミック酸の分子量は約８０,０００であった。
高純度のフラーレンＣ６０［９９.９８重量％、Ｔｅｒｍ社製］０.７５ｇと上記のフルフリル基部分置換ポリアミック酸１０.０ｇをγ−ブチロラクトン／１,１,２,２−テトラクロロエタン（７０／３０、容量比）５０mlに溶解して均一な溶液とした。この溶液をポアサイズ０.１μｍのフィルターでろ過したのち、シリコンウエハー上にスピンコート法により塗布し、８０℃で１０分間の加熱乾燥を行うことにより膜厚２μｍの薄膜を形成した。この薄膜にフォトマスクを介して５００Ｗ超高圧水銀灯により露光し、直ちに１０重量％ＴＭＡＨ水溶液に浸漬して現像処理を行ったが、１分間以上浸漬しても未露光部の残渣が完全には除去されなかった。
【００１７】
参考例１（３,５−ジアミノベンジル−２−フロエートの製造）
３,５−ジニトロベンジル−２−フロエートの製造：撹拌機、水冷式還流冷却管、温度計及び滴下ロートを備えた５００mlセパラブルフラスコ中で、３,５−ジニトロベンジルアルコール３７.０ｇをピリジン１００mlに溶解した。０〜５℃に冷却しながら、２−フロイルクロリド５３.１ｇを滴下した。滴下終了後、反応液を室温に戻し、２時間撹拌した。４００mlの水を加え、固体をろ過した。得られた固体をエチルアルコール／水（８０／２０、容量比）から再結晶し、３,５−ジニトロベンジル−２−フロエート４７ｇを得た。収率８６％。融点１１６.０〜１１７.７℃。
３,５−ジアミノベンジル−２−フロエートの製造：撹拌機、水冷式還流冷却管を備えた１リットルのセパラブルフラスコ中で、３,５−ジニトロベンジル−２−フロエート１４.６ｇを酢酸エチル１２０mlとエチルアルコール８０mlに溶解した。塩化アンモニウム飽和水溶液１２０mlを加えたのち、インジウム金属粉末１００ｇを添加した。還流下、１７時間撹拌して還元反応を行った。反応終了後、反応溶液を２リットルのビーカーに移し、１リットルの水を加え、固体をろ別した。ろ液のpHを２規定水酸化ナトリウム水溶液で９に調整したのち、酢酸エチルで抽出し、酢酸エチル層を硫酸マグネシウムで乾燥した。減圧下、酢酸エチルを留去し、粗生成物１０ｇを得た。粗生成物をシリカゲルカラムクロマトグラフィーにより精製し、３,５−ジアミノベンジル−２−フロエート４.６ｇを得た。収率４０％。エチルアルコールから再結晶し、融点１１９〜１２１.１℃の針状結晶を得た。
さらに、同じ合成と精製を２回繰り返した。
【００１８】
実施例３
参考例１で合成した３,５−ジアミノベンジル−２−フロエート９.０９ｇ（０.０３９２モル）と４,４'−ヘキサフルオロイソプロピリデン二フタル酸無水物１７.４１ｇ（０.０３９２モル）をγ−ブチロラクトン５０ml中、室温で撹拌し、式［１−(１)］で表される構造単位を有するポリアミック酸の溶液を得た。この溶液に、Ｎ−メチル−２−ピロリドン５０mlを加えて希釈し、水／メタノール（７５／２５、容量比）に注いでポリアミック酸を凝固沈殿させ、ろ過及び真空乾燥することにより淡黄色粉末の式［１−(１)］で表される構造単位を有するポリアミック酸２５.９ｇを得た。
高純度のフラーレンＣ６０［９９.９８重量％、Ｔｅｒｍ社製］０.７５ｇと上記のフロイル基置換ポリアミック酸１０.０ｇをγ−ブチロラクトン／１,１,２,２−テトラクロロエタン（７０／３０、容量比）５０mlに溶解して均一な溶液とした。この溶液をポアサイズ０.１μｍのフィルターでろ過したのち、シリコンウエハー上にスピンコート法により塗布し、８０℃で１０分間の加熱乾燥を行うことにより膜厚２μｍの薄膜を形成した。この薄膜にフォトマスクを介して５００Ｗ超高圧水銀灯により露光し、直ちに１０重量％ＴＭＡＨ水溶液に３０秒間浸漬して現像処理を行うことにより未露光部を完全に溶解除去し、線幅５μｍ以下の樹脂パターンを形成した。
得られた樹脂パターンを、２００℃で１時間加熱することにより樹脂層を形成した。この樹脂層について、室温〜３００℃までの熱重量減少率を測定したところ、０.３重量％であった。
【００１９】
参考例２（３,３'−ジアミノ−４,４'−ジ−２−フロイルアミノビフェニルの製造）
３,３'−ジニトロ−４,４'−ジ−２−フロイルアミノビフェニルの製造：撹拌機、水冷式還流冷却管、温度計及び滴下ロートを備えた５００mlセパラブルフラスコ中で、３,３'−ジニトロ−４,４'−ジアミノビフェニル１０.９６ｇをＮ,Ｎ−ジメチルホルムアミド２００mlに溶解したのち、ピリジン２０mlを加えた。１３〜１４℃に冷却しながら、２−フロイルクロリド１２.５３ｇを滴下した。滴下終了後、反応溶液を室温に戻し、５時間撹拌を続けた。２規定塩酸８０ml、次いで水１００mlを加え、固体をろ過した。固体をよく水洗したのち、減圧乾燥して３,３'−ジニトロ−４,４'−ジ−２−フロイルアミノビフェニル１５.０ｇを得た。収率８１％。
３,３'−ジアミノ−４,４'−ジ−２−フロイルアミノビフェニルの製造：撹拌機及び水冷式還流冷却管を備えたセパラブルフラスコ中に、３,３'−ジニトロ−４,４'−ジ−２−フロイルアミノビフェニル７.４ｇ、Ｎ−メチル−２−ピロリドン１００ml及びエチルアルコール７５mlを仕込んだ。塩化アンモニウム飽和水溶液４０mlを加えたのち、インジウム金属粉末２５.６ｇを添加し、８０℃にて１時間撹拌した。反応溶液を室温まで冷却したのち、固形物をろ別した。ろ液を減圧下約１／２に濃縮したのち、水３００mlを加え、析出した固体をろ過して粗生成物２.９ｇを得た。粗生成物をシリカゲルカラムクロマトグラフィーにより精製し、３,３'−ジアミノ−４,４'−ジ−２−フロイルアミノビフェニル１.５ｇを得た。単離収率２３％。Ｎ−メチル−２−ピロリドン／酢酸エチル（２５／７５、容量比）から再結晶し、分解点２５６〜２５９℃の針状結晶を得た。
さらに、同じ合成と精製を１２回繰り返した。
【００２０】
実施例４
参考例２で合成した３,３'−ジアミノ−４,４'−ジ−２−フロイルアミノビフェニル１５.７６ｇ（０.０３９２モル）と４,４'−ヘキサフルオロイソプロピリデン二フタル酸無水物１７.４１ｇ（０.０３９２モル）をγ−ブチロラクトン５０ml中、室温で撹拌し、式［２−(１)］で表される構造単位を有するポリアミック酸の溶液を得た。この溶液にＮ−メチル−２−ピロリドン５０mlを加えて希釈し、水／メタノール（７５／２５、容量比）に注いでポリアミック酸を凝固沈殿させ、ろ過及び真空乾燥することにより淡黄色粉末の式［２−(１)］で表される構造単位を有するポリアミック酸３１.５ｇを得た。
高純度のフラーレンＣ６０［９９.９８重量％、Ｔｅｒｍ社製］０.７５ｇと上記のフロイル基置換ポリアミック酸１０.０ｇをγ−ブチロラクトン／トルエン（６０／４０、容量比）５０mlに溶解して均一な溶液とした。
この溶液をポアサイズ０.１μｍのフィルターでろ過したのち、シリコンウエハー上にスピンコート法により塗布し、８０℃で１０分間の加熱乾燥を行うことにより膜厚２μｍの薄膜を形成した。この薄膜にフォトマスクを介して５００Ｗ超高圧水銀灯により露光し、直ちに１０重量％ＴＭＡＨ水溶液に３０秒間浸漬して現像処理を行うことにより未露光部を完全に溶解除去し、線幅５μｍ以下の樹脂パターンを形成した。
得られた樹脂パターンを、２００℃で１時間加熱することにより樹脂層を形成した。この樹脂層について、室温〜３００℃までの熱重量減少率を測定したところ、０.２重量％であった。
【００２１】
【発明の効果】
本発明の感光性樹脂組成物は、耐熱性ネガ型フォトレジストとして優れた性能を有する。本発明組成物に用いるポリアミック酸やポリイミドは、本来アルカリ水溶液などの溶媒に可溶であるが、フラーレンＣ６０などの酸素増感剤から生じる一重項酸素によって側鎖のcis−ジエン基が酸化重縮合を起こして架橋し、溶媒に不溶となる。したがって、従来の耐熱性フォトレジスト組成物では達成できなかった高感度、高解像度で実用に供し得るネガ型のパターンが得られる。特に、フラーレンを酸素増感剤として用いると、パターン形成後の樹脂層の耐熱性が顕著に向上する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photosensitive resin composition. More specifically, the present invention can be applied to the production of semiconductor elements, circuit wiring boards, etc., and is a negative photosensitive resin composition capable of obtaining a resin layer with high sensitivity and resolution and excellent heat resistance. Related to things.
[0002]
[Prior art]
In recent years, electronic devices have been rapidly becoming lighter, thinner, and more functional due to portability. Along with this, miniaturization and high integration of semiconductor elements are progressing. For example, the reliability of semiconductor circuits formed on semiconductor chips is ensured by increasing the integration of the circuits themselves and miniaturizing the circuits by reducing the package size, and reducing the thickness of the package sealing material that protects the chips. In general, a protective film such as a passivation film is used on the circuit on the chip surface. In addition, for further higher integration, the number of stages of circuits has been increased through an interlayer insulating film.
On the other hand, on the side of the semiconductor package that encapsulates the semiconductor chip, a new package that realizes high-density mounting such as ball grid array (BGA), chip scale package (CSP), and multichip module (MCM). Technology has been developed. These semiconductor packages use a substrate made of various materials such as plastic and ceramics called an interposer to electrically connect the electrodes of the semiconductor chip and the printed wiring board. The circuit configured on this substrate is introduced into a miniaturized semiconductor, and is much thinner and higher in density than a general printed wiring board. Therefore, it is necessary to protect this fine wiring depending on the package type. Furthermore, even for printed circuit wiring boards on which these semiconductor packages are mounted, new technologies such as a build-up method that gradually forms a wiring layer with insulating resin on the substrate to increase the wiring density Has been developed.
The requirements that are commonly required for these protective resins or interlayer insulating resins are high heat resistance that can withstand high temperatures of 200 to 300 ° C. during chip bonding and mounting, and conduction between wiring junctions and interlayers of insulating layers. In particular, the protective film for interposers and interlayer insulation films for build-up circuit boards that require processing on the substrate have low-temperature processability that does not damage the substrate during processing. Can be mentioned.
Conventionally, polyimide resins are used for applications such as protective films on semiconductor chips that require heat resistance, and epoxy resins are used as protective films and interlayer insulation films on circuit substrates that require low-temperature processability. It was. Further, in order to perform pattern processing such as holes corresponding to high-density circuit wiring, it is advantageous to form by photoengraving (photographing method), that is, to use a photosensitive resin that imparts photosensitivity to these resins. is there.
As the polyimide resin, polyimide having such photosensitivity, so-called photosensitive polyimide, has been developed (for example, Japanese Patent Publication No. 55-30207, Japanese Patent Laid-Open No. 54-145794) and used. These photosensitive polyimides generally form a cross-linked structure by radical photopolymerization of methacrylate introduced into the carboxyl group of polyamic acid, which is the precursor, and make use of the difference in solubility with the uncrosslinked part in the developer. Pattern processing such as holes is performed. When such a polyamic acid is converted to polyimide, it is necessary to remove the methacrylate that forms a bond with the carboxyl group, and a stronger heating is required as compared with the conventional thermal ring-closing imidization of the polyamic acid. Moreover, if the desorbed methacrylate structure remains in the polyimide, the properties such as heat resistance and mechanical properties are greatly reduced. In order to exhibit the high properties inherent in polyimide, the desorbed methacrylate structure is decomposed and volatilized at a high temperature. It is necessary to let Therefore, such a photosensitive polyimide needs to be processed at a higher temperature than a normal polyimide resin. In order to improve such high-temperature processing, a resin in which an acrylate structure is introduced into a side chain of a polyimide ring-closed in advance to realize low-temperature workability has been proposed (Japanese Patent Laid-Open No. 59-108031). After processing, the acrylate structure remains in the resin as it is, resulting in inferior properties such as heat resistance.
As for epoxy resins, various photosensitive epoxy resins have been put into practical use as solder resists for circuit wiring protection and interlayer insulation resins for buildup. However, there is nothing that sufficiently satisfies characteristics such as heat resistance and flexibility to follow the deformation of the base material that is thinned by thinning the package.
As a photosensitive material composition suitable as a resist having high resolution and high sensitivity, a photosensitive material composition comprising a fullerene having no photosensitive group and a photosensitive agent such as a diazide compound has been proposed (Japanese Patent No. 2814174). However, since this composition is composed of fullerene and a low molecular weight diazide compound, the viscosity of the solution is low, and it is difficult to apply uniformly while maintaining the required thickness by spin coating. The strength and heat resistance of the film formed by polymerization and crosslinking of the molecular weight diazide compound are low, and there is also an economic problem that at present, an extremely expensive fullerene is blended at least 5 times the weight of the diazide compound.
[0003]
[Problems to be solved by the invention]
The present invention provides a negative photosensitive resin composition that can be applied to the production of semiconductor elements, circuit wiring boards, etc., and that can obtain a resin layer with high sensitivity and resolution and excellent heat resistance. It was made for the purpose.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have formulated an oxygen sensitizer, particularly fullerene, in a cis-diene-substituted polyamic acid or polyimide having a specific molecular structure in the side chain. Thus, it has been found that a photosensitive resin composition having significantly improved sensitivity, resolution and heat resistance as compared with conventional heat-resistant photosensitive resins can be obtained, and the present invention has been completed based on this finding.
That is, the present invention
(1) A photosensitive resin composition comprising a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by the general formula [1] and an oxygen sensitizer,
[Chemical 3]

(However, in the formula, R ¹ , R ² , R ^Three And R ^Four At least one of Furan, thiophene or pyrrole structure a monovalent organic group having a cis-diene structure, and the remainder is independently hydrogen, a hydroxyl group, a carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxyl group having 1 to 20 carbon atoms, ¹ And X ² Are each independently oxygen, sulfur or an alkylene group or alkyleneoxy group optionally having a substituent of 1 to 4 carbon atoms; Ar ¹ And Ar ² Are each independently a divalent aromatic group, ₁ , L ₂ , M ₁ And m ₂ Are each independently 0 or 1. However, l ₁ M is 1 ₁ Is 1 and l ₂ M is 1 ₂ Is also 1. ),
(2) A photosensitive resin composition comprising a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by the general formula [2] and an oxygen sensitizer,
[Formula 4]

(However, in the formula, R ^Five , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ^Ten , R ¹¹ And R ¹² At least one of Furan, thiophene or pyrrole structure a monovalent organic group having a cis-diene structure, and the remainder is each independently hydrogen, a hydroxyl group, a carboxyl group, an alkyl group having 1 to 20 carbon atoms, or an alkoxyl group having 1 to 20 carbon atoms; ¹ Is oxygen, sulfur or an alkylene group, alkylidene group or alkyleneoxy group which may have a substituent of 1 to 4 carbon atoms, n ₁ Is 0 or 1. ),as well as,
( 3 ) The oxygen sensitizer is fullerene (1) or ( 2 ) Item photosensitive resin composition,
Is to provide.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The 1st form of the photosensitive resin composition of this invention contains the cis-diene substituted polyamic acid or polyimide which has a structural unit represented by General formula [1], and an oxygen sensitizer.
[Chemical formula 5]

However, in the general formula [1], R ¹ , R ² , R ^Three And R ^Four At least one of them is a monovalent organic group having a cis-diene structure, and the remainder is independently hydrogen, a hydroxyl group, a carboxyl group, an alkyl group having 1 to 20 carbon atoms, or an alkoxyl group having 1 to 20 carbon atoms. And X ¹ And X ² Are each independently oxygen, sulfur or an alkylene group or alkyleneoxy group optionally having a substituent of 1 to 4 carbon atoms; Ar ¹ And Ar ² Are each independently a divalent aromatic group, ₁ , L ₂ , M ₁ And m ₂ Are each independently 0 or 1. However, l ₁ M is 1 ₁ Is 1 and l ₂ M is 1 ₂ Is also 1.
[0006]
The 2nd form of the photosensitive resin composition of this invention contains the cis-diene substituted polyamic acid or polyimide which has a structural unit represented by General formula [2], and an oxygen sensitizer.
[Chemical 6]

However, R ^Five , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ^Ten , R ¹¹ And R ¹² At least one of them is a monovalent organic group having a cis-diene structure, and the remainder is independently hydrogen, a hydroxyl group, a carboxyl group, an alkyl group having 1 to 20 carbon atoms, or an alkoxyl group having 1 to 20 carbon atoms. And Y ¹ Is oxygen, sulfur or an alkylene group, alkylidene group or alkyleneoxy group which may have a substituent of 1 to 4 carbon atoms, n ₁ Is 0 or 1. An atom such as halogen for replacing hydrogen is also a substituent.
In the composition of the present invention, the cis-diene-substituted polyamic acid or polyimide having the structural unit represented by the general formula [1] or [2] is substituted with a monovalent organic group having a cis-diene structure. The main chain is bonded to the meta position of the aromatic ring. When the main chain is bonded to the para position of the aromatic ring, the molecular packing such as the crystallinity of polyamic acid or polyimide tends to increase. In particular, dissolution in a developer with a cis-diene structure introduced The nature will decline. As a result, when creating an optical pattern, a difference in dissolution rate between the unexposed portion that should be dissolved in the developer and the photocrosslinked exposed portion with respect to the developer is less likely to occur, and a large amount of exposure is required for contrast development. Therefore, there is a possibility that the pattern forming ability may be greatly deteriorated, such that it is difficult to obtain a resin pattern having a good shape, and it is difficult to completely remove the resin in the unexposed area. If a bond to the main chain is present at the meta position of the aromatic ring substituted with a monovalent organic group having a cis-diene structure as in the composition of the present invention, the corresponding polyamic acid and polyimide can be developed. The solubility is improved, and as a result, the contrast between the exposed part and the unexposed part becomes clear, and the photopatterning property is improved.
[0007]
In the composition of the present invention, the structural unit represented by the general formula [1] or the general formula [2] may be present alone in the polyamic acid or polyimide, and two or more types are present as copolymer units. May be. In the composition of the present invention, the cis-diene-substituted polyamic acid or polyimide having the structural unit represented by the general formula [1] or the general formula [2] may contain only one type or two or more types. It may be mixed and contained. The composition of the present invention is represented by cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [1] or general formula [2], and general formula [1] or general formula [2]. It is also possible to use a mixture with a polyamic acid or a polyimide that does not have a structural unit.
In the general formula [1] and the general formula [2], examples of the monovalent organic group having a cis-diene structure include —CH ₂ O-CO-D, -O-CO-D, -CO-O-CH ₂ -D, -CH ₂ O-CH ₂ -D, -O-CH ₂ -D, -NH-CO-D, -CO-NH-CH ₂ -D etc. can be mentioned. However, D is a cis-diene structure. Examples of the cis-diene structure represented by D include a cyclopentadienyl group, a furyl group, a pyrrolyl group, a thienyl group, a pyranyl group, an isobenzofuranyl group, an indolizinyl group, and a quinolidinyl group. Of these, a cyclopentadienyl group, a furyl group, a pyrrolyl group, and a thienyl group are particularly preferable.
In the general formula [1] and the general formula [2], examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, A decyl group, a lauryl group, etc. can be mentioned. Among these, a methyl group, an ethyl group, a butyl group, and a pentyl group are particularly preferable.
In the general formula [1] and the general formula [2], examples of the alkoxyl group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a lauryloxy group, and an isopropyloxy group. And so on. Among these, a methoxy group, an ethoxy group, a butoxy group, and a pentyloxy group are particularly preferable.
[0008]
Examples of the structural unit represented by the general formula [1] having these functional groups include structural units represented by the following formulas [1- (1)] to [1- (20)]. Examples of the structural unit represented by the general formula [2] include structural units represented by the formulas [2- (1)] to [2- (10)].
[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical Formula 10]

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There is no restriction | limiting in particular in the manufacturing method of the cis-diene substituted polyamic acid or polyimide which has a structural unit represented by General formula [1] or General formula [2] used for this invention composition, For example, the diamine which has a hydroxyl group, After reacting the polycarboxylic acid dianhydride, a monovalent organic group having a cis-diene structure can be introduced, or a diamine having a monovalent organic group having a cis-diene structure and a polycarboxylic acid dihydrate. Anhydrides can also be reacted.
In the present invention, the polycarboxylic dianhydride to be reacted with the diamine is not particularly limited. For example, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 Examples include '4,4'-biphenyltetracarboxylic dianhydride, 4,4'-hexafluoroisopropylidene diphthalic anhydride. Among these, 4,4′-hexafluoroisopropylidene diphthalic anhydride can be particularly preferably used.
[0009]
When introducing a monovalent organic group having a cis-diene structure into a polyamic acid or polyimide obtained by polymerizing a diamine having no monovalent organic group having a cis-diene structure and a polycarboxylic dianhydride, A diamine represented by the general formula [3] or the general formula [4] and a polycarboxylic dianhydride can be used as starting materials.
Embedded image

However, in the general formula [3], R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ At least one is a hydroxyl group, a hydroxymethyl group, or a carboxyl group, and the remainder is independently hydrogen, an alkyl group having 1 to 20 carbon atoms, or an alkoxyl group having 1 to 20 carbon atoms, and X ^Three And X ^Four Are each independently oxygen, sulfur or an alkylene group or alkyleneoxy group optionally having a substituent of 1 to 4 carbon atoms; Ar ^Three And Ar ^Four Are each independently a divalent aromatic group, _Three , L _Four , M _Three And m _Four Are each independently 0 or 1. However, l _Three M is 1 _Three Is 1 and l _Four M is 1 _Four Is also 1. In the general formula [4], R ¹⁷ , R ¹⁸ , R ¹⁹ , R ²⁰ , R ^{twenty one} , R ^{twenty two} , R ^{twenty three} And R ^{twenty four} At least one of them is a hydroxyl group, a hydroxymethyl group or a carboxyl group, and the remainder is independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an alkoxyl group having 1 to 20 carbon atoms, and Y ² Is oxygen, sulfur or an alkylene group, alkylidene group or alkyleneoxy group which may have a substituent of 1 to 4 carbon atoms, n ₂ Is 0 or 1. An atom such as halogen for replacing hydrogen is also a substituent.
Examples of the diamine represented by the general formula [3] include 3,5-diaminobenzyl alcohol, 3,5-diaminophenol, 3,5-diaminobenzoic acid, and the like. Examples of the diamine represented by the general formula [4] include 3,3′-diamino-4,4′-dihydroxybiphenyl, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 3 , 5-bis (4-aminophenoxy) benzyl alcohol and the like.
[0010]
In the present invention, the method for reacting the diamine represented by the general formula [3] or the general formula [4] with the polycarboxylic dianhydride is not particularly limited, and a polyamic acid can be synthesized by a known polymerization method. . For example, the diamine represented by the general formula [3] and pyromellitic dianhydride are reacted in a solvent such as N-methyl-2-pyrrolidone to thereby have the structural unit represented by the general formula [5]. A polyamic acid can be obtained. Furthermore, the polyimide which has a structural unit represented by General formula [6] can be obtained by carrying out dehydration ring-closing reaction of the polyamic acid which has a structural unit represented by General formula [5].
Embedded image

Particularly limited to a method of introducing a monovalent organic group having a cis-diene structure into a polyamic acid having a structural unit represented by the general formula [5] or a polyimide having a structural unit represented by the general formula [6]. For example, by reacting a halide having a cis-diene structure in the presence of a base, a polyamic acid having a structural unit represented by the general formula [5] or a structure represented by the general formula [6] A monovalent organic group having a cis-diene structure can be introduced into a hydroxyl group of a polyimide having a unit. In the general formula [5], R ¹⁵ Is a hydroxyl group, and when the halide having a cis-diene structure is furfuryl bromide, a polyamic acid having a structural unit represented by the general formula [7] is obtained.
Embedded image

[0011]
In the present invention, when a polyamic acid or a polyimide is synthesized by a reaction of a diamine having a monovalent organic group having a cis-diene structure and a polycarboxylic dianhydride, a monovalent having a cis-diene structure that can be used. Examples of the diamine having an organic group of 3,5-diaminobenzyl-2-furoate, 1,1,1,3,3,3-hexafluoro-2,2-bis (4-furfuryloxy-3) -Aminophenyl) propane, 3,3'-diamino-4,4'-di (2-furoylamino) biphenyl, 4,4'-difurfuryloxy-3,3'-diaminobiphenyl, and the like. These diamines, for example, react an aromatic dinitro compound having a hydroxyl group, a carboxyl group or a hydroxyalkyl group with a halide having a cis-diene structure such as furfuryl bromide in the presence of a base, and subsequently reacting the nitro group. It can be obtained by a reduction method or the like. The method for reducing the nitro group is not particularly limited, and examples thereof include reduction with hydrazine, catalytic hydrogenation reaction in the presence of a transition metal catalyst such as nickel, palladium, platinum, and reduction with an indium-ammonium chloride aqueous solution.
The cis-diene-substituted polyamic acid or polyimide having the structural unit represented by the general formula [1] or the general formula [2] used in the present invention is soluble in a solvent or an alkaline aqueous solution. This polyamic acid or polyimide easily reacts with singlet oxygen generated by the action of the oxygen sensitizer, and forms an intermediate of polyamic acid or polyimide having a peracid group. This intermediate immediately reacts with the adjacent polyamic acid or polyimide and crosslinks with each other by a polycondensation reaction, thereby dramatically increasing the molecular weight. Thereby, polyamic acid or polyimide becomes insoluble. Furthermore, the heat resistance of the polyamic acid or polyimide crosslinked by the polycondensation reaction is dramatically increased. Unlike the conventional photosensitive polyimide, the photosensitive resin composition of the present invention is cross-linked by polycondensation of the cis-diene structure with singlet oxygen regardless of photoradical polymerization, so that it reacts with oxygen in the air. Is not inhibited, and the resulting crosslinked resin has excellent heat resistance.
[0012]
In the present invention, the molecular weight of the cis-diene-substituted polyamic acid or polyimide having the structural unit represented by the general formula [1] or the general formula [2] is preferably 5,000 or more, and is preferably 10,000 to 1. Is more preferably 50,000,000, and even more preferably 50,000 to 200,000. If the molecular weight of the polyamic acid or polyimide is too small, it may be difficult to obtain a uniform film. If the molecular weight of the polyamic acid or polyimide is too large, the solubility is lowered and it may be difficult to form a uniform film.
Although there is no restriction | limiting in particular in the oxygen sensitizer used for this invention composition, It is preferable that it is an oxygen sensitizer whose excitation triplet energy is 22.5 kilocalories / mol or more. Examples of such oxygen sensitizers include methylene blue, rose bengal, hematoporphyrin, tetraphenylporphine, rubrene, fullerene C60, fullerene C70, and fullerene C82. These oxygen sensitizers can be used alone or in combination of two or more. Among these, fullerene C60 and fullerene C70 can be particularly preferably used.
In the composition of the present invention, the blending amount of the oxygen sensitizer is not particularly limited, but 100 parts by weight of cis-diene-substituted polyamic acid or polyimide having a structural unit represented by the general formula [1] or the general formula [2] The amount is preferably from 0.01 to 20 parts by weight, more preferably from 0.1 to 10 parts by weight. If the blending amount of the oxygen sensitizer is too small, the sensitization effect may be insufficient. If the amount of the oxygen sensitizer is too large, it is not only economically disadvantageous but also it may be difficult to form a uniform film. The composition of the present invention containing a high molecular weight cis-diene-substituted polyamic acid or polyimide and an oxygen sensitizer has an appropriate viscosity when used as a solution and maintains the necessary film thickness on a silicon wafer by spin coating. It can be applied uniformly. Moreover, since a film is formed by crosslinking of the high molecular weight cis-diene-substituted polyamic acid or polyimide in the composition, the film is excellent in strength and heat resistance. Further, since an expensive oxygen sensitizer such as fullerene is used in a relatively small amount, it can be produced economically advantageously.
[0013]
Although there is no restriction | limiting in particular in the usage method of the photosensitive resin composition of this invention, Generally, after forming a coating film on a base material and a substrate and performing pattern processing by exposure and development, as needed Then, the resin layer is formed by further thermosetting. There are no particular restrictions on the method of forming the coating film. For example, a varnish obtained by dissolving a photosensitive resin composition in a solvent is applied directly onto a substrate / substrate by spin coating, and then dried under mild conditions. Or by applying a varnish obtained by dissolving in a solvent to a release substrate made of a metal such as a plastic sheet or stainless steel, and drying it under mild conditions. Examples of the method include a method in which pressure is laminated and transferred.
The wavelength of light used for exposure of the composition of the present invention can be appropriately selected according to the oxygen sensitizer used. For example, when fullerene C60 is used as a sensitizer, light in a wide wavelength range (250 to 780 nm) from the ultraviolet range to the visible light range can be used. The exposure can be performed by irradiating the resin layer with light through a mask capable of shielding a portion of the formed resin layer where the resin is to be removed. Development after exposure can be performed using an organic solvent or an aqueous alkali solution that dissolves the unexposed resin composition. The resin in the exposed area is insolubilized by the reaction, but the resin in the unexposed area is dissolved, and as a result, pattern processing such as holes can be performed on the resin with the mask.
The cis-diene-substituted polyamic acid having the structural unit represented by the general formula [1] or the general formula [2] can be thermally cured after development, and the polyamic acid can be converted to polyimide by a dehydration cyclization reaction. Although there is no restriction | limiting in particular in the conditions of thermosetting reaction, Usually, it is preferable to heat at 150-250 degreeC for 30 minutes or more. Heating can be performed with hot air, infrared irradiation, a hot platen, or the like. Usually, it can be carried out in an air atmosphere, but it can also be carried out under an inert gas atmosphere such as nitrogen or carbon dioxide, under reduced pressure, etc., if necessary. The cis-diene-substituted polyimide does not necessarily need to undergo a thermosetting reaction, but can be heated at the above temperature conditions to give a high thermal history to the resin and further improve heat resistance. By using the resin composition of the present invention in these processing steps, a patterned resin layer having excellent heat resistance is formed by processing at a low temperature, and semiconductor elements having good characteristics, printed circuit wiring boards, etc. Can be manufactured.
[0014]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
In a 50 ml portion of N-methyl-2-pyrrolidone, 8.47 g (0.0392 mol) of 3,3′-diamino-4,4′-dihydroxybiphenyl and 8.55 g (0.0392 mol) of pyromellitic anhydride were added in 60 ml. The mixture was stirred at 0 ° C. to obtain a polyamic acid solution.
On the other hand, 5.00 g (0.0510 mol) of furfuryl alcohol was dissolved in 50 ml of tetrahydrofuran, and 4.90 g (0.0181 mol) of phosphorus tribromide was added dropwise while maintaining the temperature at 0 ° C. After stirring for about 2 hours, water was added and the organic component was extracted twice with 100 ml of ether. The ether layer was washed with sodium hydrogen carbonate, added with 30 g of molecular sieve, dried overnight, and filtered to obtain an ether solution of furfuryl bromide. FT-IR for the resulting solution, ¹ H-NMR and ¹³ C-NMR analysis was performed and it was confirmed to be furfuryl bromide.
Next, 150 ml of N-methyl-2-pyrrolidone is added to the above polyamic acid solution for dilution, an ether solution containing 7.70 g of furfuryl bromide and 6.50 g of potassium carbonate are added, and the mixture is heated at 80 ° C. for about 2 hours. Stir. Next, re-solidification precipitation treatment was performed using methanol, and the precipitate was vacuum-dried to obtain 16.3 g of a polyamic acid having a structural unit represented by the formula [2- (10)]. ¹ When analyzed by 1 H-NMR, 80 mol% of the diamine structural unit in the polyamic acid was substituted with a furfuryl group. The molecular weight of this polyamic acid was about 70,000.
0.75 g of high-purity fullerene C60 [99.98 wt%, manufactured by Term Co.] and 10.0 g of the furfuryl group partially substituted polyamic acid were mixed with γ-butyrolactone / 1,1,2,2-tetrachloroethane (70 / (30, volume ratio) was dissolved in 50 ml to obtain a uniform solution. The solution was filtered through a filter having a pore size of 0.1 μm, and then applied onto a silicon wafer by spin coating, followed by heat drying at 80 ° C. for 10 minutes to form a thin film having a thickness of 2 μm. By exposing the thin film to a 500 W ultrahigh pressure mercury lamp through a photomask (letterpress test chart) and immediately immersing it in a 10 wt% tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds, an unexposed portion is obtained. Was completely dissolved and removed to form a resin pattern having a line width of 5 μm or less.
The obtained resin pattern was heated at 200 ° C. for 1 hour to form a resin layer. With respect to this resin layer, the thermal weight loss rate from room temperature to 300 ° C. was measured with a TG / DTA apparatus [Seiko Denshi Kogyo Co., Ltd., TG / DTA220 type, temperature rising rate: 10 ° C./min] to find 0.3. % By weight.
[0015]
Example 2
14.36 g (0.0392 mol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane and 8.55 g (0.0392 mol) of pyromellitic dianhydride were added to N-methyl-2- The mixture was stirred at 50 ° C. in 50 ml of pyrrolidone to obtain a polyamic acid solution.
Next, 150 ml of N-methyl-2-pyrrolidone was added to the polyamic acid solution for dilution, an ether solution containing 7.70 g of furfuryl bromide and 6.50 g of potassium carbonate were added, and the mixture was stirred at 80 ° C. for about 2 hours. . Next, re-solidification precipitation treatment was performed using methanol, and the precipitate was vacuum-dried to obtain 20.3 g of a polyamic acid having a structural unit represented by the formula [2- (5)]. ¹ When analyzed by 1 H-NMR, 80 mol% of the diamine structural unit in the polyamic acid was substituted with a furfuryl group. The molecular weight of this polyamic acid was about 50,000.
0.75 g of high-purity fullerene C60 [99.98 wt%, manufactured by Term Co.] and 10.0 g of the above furfuryl group partially substituted polyamic acid were mixed with γ-butyrolactone / 1,1,2,2-tetrachloroethane (70/30 , Volume ratio) was dissolved in 50 ml to obtain a uniform solution. The solution was filtered through a filter having a pore size of 0.1 μm, and then applied onto a silicon wafer by spin coating, followed by heat drying at 80 ° C. for 10 minutes to form a thin film having a thickness of 2 μm. The thin film is exposed with a 500 W ultra high pressure mercury lamp through a photomask and immediately immersed in a 10 wt% TMAH aqueous solution for 30 seconds to develop and remove the unexposed portion completely, and a resin having a line width of 5 μm or less. A pattern was formed.
The obtained resin pattern was heated at 200 ° C. for 1 hour to form a resin layer. About this resin layer, it carried out similarly to Example 1, and it was 0.5 weight% when the thermogravimetric reduction rate from room temperature to 300 degreeC was measured with the TG / DTA apparatus.
[0016]
Comparative Example 1
A polyamic acid partially substituted with a furfuryl group was synthesized in the same manner as in Example 1 except that 8.47 g (0.0392 mol) of 4,4′-diamino-3,3′-dihydroxybiphenyl was used as the diamine component. did. ¹ When analyzed by 1 H-NMR, 85 mol% of the diamine structural unit in the polyamic acid was substituted with a furfuryl group. The molecular weight of this polyamic acid was about 80,000.
0.75 g of high-purity fullerene C60 [99.98 wt%, manufactured by Term Co.] and 10.0 g of the above furfuryl group partially substituted polyamic acid were mixed with γ-butyrolactone / 1,1,2,2-tetrachloroethane (70/30 , Volume ratio) was dissolved in 50 ml to obtain a uniform solution. The solution was filtered through a filter having a pore size of 0.1 μm, and then applied onto a silicon wafer by spin coating, followed by heat drying at 80 ° C. for 10 minutes to form a thin film having a thickness of 2 μm. The thin film was exposed to light with a 500 W ultra high pressure mercury lamp through a photomask and immediately developed in a 10 wt% TMAH aqueous solution. The residue in the unexposed area was completely removed even after immersion for 1 minute or longer. Was not.
[0017]
Reference Example 1 (Production of 3,5-diaminobenzyl-2-furoate)
Preparation of 3,5-dinitrobenzyl-2-furoate: 3500 g of 3,5-dinitrobenzyl alcohol in 100 ml of pyridine in a 500 ml separable flask equipped with a stirrer, water-cooled reflux condenser, thermometer and dropping funnel Dissolved in. While cooling to 0 to 5 ° C., 53.1 g of 2-furoyl chloride was added dropwise. After completion of dropping, the reaction solution was returned to room temperature and stirred for 2 hours. 400 ml of water was added and the solid was filtered. The obtained solid was recrystallized from ethyl alcohol / water (80/20, volume ratio) to obtain 47 g of 3,5-dinitrobenzyl-2-furoate. Yield 86%. Melting point 116.0-117.7 ° C.
Preparation of 3,5-diaminobenzyl-2-furoate: In a 1 liter separable flask equipped with a stirrer and a water-cooled reflux condenser, 14.6 g of 3,5-dinitrobenzyl-2-furoate was added to 120 ml of ethyl acetate. And dissolved in 80 ml of ethyl alcohol. After adding 120 ml of saturated aqueous ammonium chloride solution, 100 g of indium metal powder was added. The mixture was stirred for 17 hours under reflux to carry out a reduction reaction. After completion of the reaction, the reaction solution was transferred to a 2 liter beaker, 1 liter of water was added, and the solid was filtered off. The pH of the filtrate was adjusted to 9 with 2N aqueous sodium hydroxide solution, extracted with ethyl acetate, and the ethyl acetate layer was dried over magnesium sulfate. Ethyl acetate was distilled off under reduced pressure to obtain 10 g of a crude product. The crude product was purified by silica gel column chromatography to obtain 4.6 g of 3,5-diaminobenzyl-2-furoate. Yield 40%. Recrystallization from ethyl alcohol gave needle-like crystals having a melting point of 119 to 121.1 ° C.
Furthermore, the same synthesis and purification were repeated twice.
[0018]
Example 3
9.09 g (0.0392 mol) of 3,5-diaminobenzyl-2-furoate synthesized in Reference Example 1 and 17.41 g (0.0392 mol) of 4,4′-hexafluoroisopropylidene diphthalic anhydride were added. The mixture was stirred at room temperature in 50 ml of γ-butyrolactone to obtain a polyamic acid solution having a structural unit represented by the formula [1- (1)]. The solution was diluted with 50 ml of N-methyl-2-pyrrolidone, poured into water / methanol (75/25, volume ratio) to coagulate and precipitate polyamic acid, filtered and vacuum dried to obtain a pale yellow powder. 25.9 g of polyamic acid having a structural unit represented by the formula [1- (1)] was obtained.
0.75 g of high-purity fullerene C60 [99.98 wt%, manufactured by Term Co.] and 10.0 g of the above-mentioned furoyl group-substituted polyamic acid were mixed with γ-butyrolactone / 1,1,2,2-tetrachloroethane (70/30, (Volume ratio) It was dissolved in 50 ml to obtain a uniform solution. The solution was filtered through a filter having a pore size of 0.1 μm, and then applied onto a silicon wafer by spin coating, followed by heat drying at 80 ° C. for 10 minutes to form a thin film having a thickness of 2 μm. The thin film is exposed with a 500 W ultra high pressure mercury lamp through a photomask and immediately immersed in a 10 wt% TMAH aqueous solution for 30 seconds to develop and remove the unexposed portion completely, and a resin having a line width of 5 μm or less. A pattern was formed.
The obtained resin pattern was heated at 200 ° C. for 1 hour to form a resin layer. With respect to this resin layer, the thermal weight loss rate from room temperature to 300 ° C. was measured and found to be 0.3% by weight.
[0019]
Reference Example 2 (Production of 3,3′-diamino-4,4′-di-2-furoylaminobiphenyl)
Preparation of 3,3′-dinitro-4,4′-di-2-furoylaminobiphenyl: in a 500 ml separable flask equipped with a stirrer, water-cooled reflux condenser, thermometer and dropping funnel After dissolving 10.96 g of '-dinitro-4,4'-diaminobiphenyl in 200 ml of N, N-dimethylformamide, 20 ml of pyridine was added. While cooling to 13-14 ° C., 12.53 g of 2-furoyl chloride was added dropwise. After completion of the dropwise addition, the reaction solution was returned to room temperature and stirred for 5 hours. 80 ml of 2N hydrochloric acid and then 100 ml of water were added and the solid was filtered. The solid was thoroughly washed with water and then dried under reduced pressure to obtain 15.0 g of 3,3′-dinitro-4,4′-di-2-furoylaminobiphenyl. Yield 81%.
Production of 3,3′-diamino-4,4′-di-2-furoylaminobiphenyl: In a separable flask equipped with a stirrer and a water-cooled reflux condenser, 3,3′-dinitro-4,4 7.4 g of '-di-2-furoylaminobiphenyl, 100 ml of N-methyl-2-pyrrolidone and 75 ml of ethyl alcohol were charged. After adding 40 ml of a saturated aqueous solution of ammonium chloride, 25.6 g of indium metal powder was added and stirred at 80 ° C. for 1 hour. After the reaction solution was cooled to room temperature, the solid was filtered off. The filtrate was concentrated to about 1/2 under reduced pressure, 300 ml of water was added, and the precipitated solid was filtered to obtain 2.9 g of a crude product. The crude product was purified by silica gel column chromatography to obtain 1.5 g of 3,3′-diamino-4,4′-di-2-furoylaminobiphenyl. Isolated yield 23%. Recrystallization from N-methyl-2-pyrrolidone / ethyl acetate (25/75, volume ratio) gave needle-like crystals having a decomposition point of 256 to 259 ° C.
Furthermore, the same synthesis and purification were repeated 12 times.
[0020]
Example 4
15.76 g (0.0392 mol) of 3,3′-diamino-4,4′-di-2-furoylaminobiphenyl synthesized in Reference Example 2 and 4,4′-hexafluoroisopropylidene diphthalic anhydride 17.41 g (0.0392 mol) was stirred in 50 ml of γ-butyrolactone at room temperature to obtain a polyamic acid solution having a structural unit represented by the formula [2- (1)]. The solution is diluted with 50 ml of N-methyl-2-pyrrolidone, poured into water / methanol (75/25, volume ratio) to coagulate and precipitate polyamic acid, filtered and vacuum dried to form a pale yellow powder. 31.5 g of polyamic acid having a structural unit represented by [2- (1)] was obtained.
0.75 g of high-purity fullerene C60 [99.98 wt%, manufactured by Term Co.] and 10.0 g of the above-mentioned furoyl group-substituted polyamic acid were dissolved in 50 ml of γ-butyrolactone / toluene (60/40, volume ratio) and homogeneous. Solution.
The solution was filtered through a filter having a pore size of 0.1 μm, and then applied onto a silicon wafer by spin coating, followed by heat drying at 80 ° C. for 10 minutes to form a thin film having a thickness of 2 μm. The thin film is exposed with a 500 W ultra high pressure mercury lamp through a photomask and immediately immersed in a 10 wt% TMAH aqueous solution for 30 seconds to develop and remove the unexposed portion completely, and a resin having a line width of 5 μm or less. A pattern was formed.
The obtained resin pattern was heated at 200 ° C. for 1 hour to form a resin layer. With respect to this resin layer, the thermal weight loss rate from room temperature to 300 ° C. was measured and found to be 0.2% by weight.
[0021]
【The invention's effect】
The photosensitive resin composition of the present invention has excellent performance as a heat-resistant negative photoresist. The polyamic acid and polyimide used in the composition of the present invention are originally soluble in a solvent such as an alkaline aqueous solution, but the side chain cis-diene group is oxidatively polycondensed by singlet oxygen generated from an oxygen sensitizer such as fullerene C60. To cause crosslinking and become insoluble in the solvent. Therefore, a negative pattern that can be practically used with high sensitivity and high resolution that could not be achieved by the conventional heat-resistant photoresist composition can be obtained. In particular, when fullerene is used as an oxygen sensitizer, the heat resistance of the resin layer after pattern formation is significantly improved.

Claims (3)

A photosensitive resin composition comprising a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by the general formula [1] and an oxygen sensitizer.

(In the formula, at least one of R ¹ , R ² , R ³ and R ⁴ is a monovalent organic group having a cis-diene structure which is a furan, thiophene or pyrrole structure , and the remainder is independently Hydrogen, hydroxyl group, carboxyl group, alkyl group having 1 to 20 carbon atoms or alkoxyl group having 1 to 20 carbon atoms, and X ¹ and X ² are each independently oxygen, sulfur or a substituent having 1 to 4 carbon atoms. An alkylene group or an alkyleneoxy group which may have, Ar ¹ and Ar ² are each independently a divalent aromatic group, and l ₁ , l ₂ , m ₁ and m ₂ are each independently 0 or (However, when l ₁ is 1, m ₁ is also 1, and when l ₂ is 1, m ₂ is also 1.) A photosensitive resin composition comprising a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by the general formula [2] and an oxygen sensitizer.

(However, in the formula, at least one of R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ^11, and R ¹² is a monovalent having a cis-diene structure which is a furan, thiophene or pyrrole structure. And the remainder is independently hydrogen, hydroxyl group, carboxyl group, alkyl group having 1 to 20 carbon atoms or alkoxyl group having 1 to 20 carbon atoms, and Y ¹ is oxygen, sulfur or carbon number 1 An alkylene group, an alkylidene group or an alkyleneoxy group which may have a substituent of ˜4, and n ₁ is 0 or 1.) Oxygen sensitizer claim 1 or claim 2 photosensitive resin composition wherein the fullerene.