JP4399950B2 - Photosensitive resin composition, pattern manufacturing method, and semiconductor device - Google Patents

Description

（式中、Ａは芳香環を有する四価の有機基であり、Ｂは二価の有機基であり、Ａに結合する２つのＯＨと２つのＮＨは、１つのＯＨと１つのＮＨを１組とし、各組のＯＨとＮＨは芳香環のオルト位に位置し、Ａ及びＢに含まれる芳香環の総数は３以下である）で示される繰り返し単位を有し、フッ素原子を含有しない場合は水酸基濃度が３．３５ｍｏｌ／Ｋｇ以上であり、フッ素原子を含有する場合は水酸基濃度が２．００ｍｏｌ／Ｋｇ以上であるポリベンゾオキサゾール前駆体であって、かつ、該ポリベンゾオキサゾール前駆体から形成される塗膜の膜厚１０μｍあたりの３６５ｎｍの光線透過率が１％以上であるポリベンゾオキサゾール前駆体を含有してなる感光性樹脂組成物に関する。
前記ポリベンゾオキサゾール前駆体としては、下記一般式（２）
【化３】

（式中、ＸとＹは、各々独立に、各々の結合するベンゼン環と共役しない２価の基又は単結合を示し、Ｒ ^２ 、Ｒ ^３ 、Ｒ ^４ 及びＲ ^５ は、各々独立に一価の基を示し、２つの矢印で示される結合はそれらが逆に結合していてもよいことを示す）で示される繰り返し単位を有するものが好ましい。
【００１１】
また本発明は、組成物を用いて塗膜を形成し、硬化して得られるポリベンゾオキサゾール膜を有するシリコンウエハの残留応力が２５℃で２５ＭＰａ以下となるものである前記感光性樹脂組成物に関する。
【００１２】
また本発明は、さらに、光により酸を発生する化合物を含有する前記感光性樹脂組成物に関する。
また本発明は、前記一般式（２）のＸ及びＹが、各々独立に単結合，Ｏ，ＣＨ_２，Ｃ＝Ｏ，Ｓｉ（ＣＨ_３）_２，Ｃ（ＣＨ_３）_２，Ｃ（ＣＦ_３）_２，Ｃ（ＣＨ_３）（ＣＦ_３），Ｓｉ（ＯＣＨ_３）_２，Ｃ（ＯＣＨ_３）_２，Ｃ（ＯＣＦ_３）_２，Ｃ（ＯＣＨ_３）（ＯＣＦ_３）、Ｓ、ＳＯ_２、ＣＨ（ＣＨ_３）、ＣＨ（ＣＦ_３）、ＣＨ（ＯＣＨ_３）、ＣＨ（ＯＣＦ_３）、ＳｉＨ（ＣＨ_３）及びＳｉＨ（ＯＣＨ_３）から選択される基であり、Ｒ^２、Ｒ^３、Ｒ^４及びＲ^５が、水素原子、炭素数１〜１０のアルキル基、ＣＦ_３、ハロゲン原子、ＣＯＯＨ及びＯＨから選択される基である前記感光性樹脂組成物に関する。
【００１３】
また本発明は、前記の各感光性樹脂組成物を支持基板上に塗布し乾燥する工程、露光する工程、現像する工程及び加熱処理する工程を含むパターンの製造法に関する。
また本発明は、前記露光する工程が、露光光源としてｉ線を用いて行うものであるパターンの製造法に関する。
【００１４】
また本発明は、前記支持基板が直径３００ｍｍ以上のシリコンウエハであるパターンの製造法に関する。
また本発明は、前記の製造法により得られるパターンの層を有してなる電子部品に関する。
さらに本発明は、前記電子部品が半導体装置であり、パターンの層が表面保護膜又は層間絶縁膜である電子部品。
【００１５】
【発明の実施の形態】
本発明の感光性樹脂組成物は、前記一般式（１）で示される繰り返し単位を有するポリベンゾオキサゾール前駆体、好ましくは前記一般式（２）で示される繰り返し単位を有するポリベンゾオキサゾール前駆体を含有するものである。
ポリベンゾオキサゾール前駆体とは、閉環反応によりポリベンゾオキサゾールを形成しうるものであり、本発明では、前記一般式（１）で示される繰り返し単位、好ましくは前記一般式（２）で示される繰り返し単位を有するものである。
【００１６】
一般式（１）において、Ａは芳香環を有する四価の有機基であり、一般にジカルボン酸と反応してポリベンゾオキサゾール前駆体の構造を形成するジヒドロキシジアミンの残基である。Ａに結合する２つのＯＨと２つのＮＨは、１つのＯＨと１つのＮＨを１組とし、各組のＯＨとＮＨは芳香環のオルト位に位置する。
Ａで示される芳香環を有する四価の有機基としては、芳香環（ベンゼン環、ナフタレン環など）を少なくとも１つ有する炭素原子数が６〜２０の基が挙げられ、これはアルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基等の各種置換基を有していてもよい。
【００１７】
また、Ｂで示される二価の有機基は、一般にジヒドロキシジアミンと反応してポリベンゾオキサゾール前駆体の構造を形成するジカルボン酸の残基である。
Ｂで示される芳香環を有する二価の有機基としては、芳香環（ベンゼン環、ナフタレン環など）を少なくとも１つ有する炭素原子数が６〜２０の基が挙げられ、これは各種置換基を有していてもよい。芳香環は１つ有するものであることがアルカリ性水溶液に対する溶解性の点で好ましい。
【００１８】
一般式（１）で示される繰り返し単位において、Ａ及びＢに含まれる芳香環の総数は３以下である。ここで芳香環の数が、４以上となると、低ウエハ応力とアルカリ水溶液に対する溶解性の両立が困難という欠点がある。
また、本発明におけるポリベンゾオキサゾール前駆体は、フッ素原子を含有しない場合は水酸基濃度が３．３５ｍｏｌ／Ｋｇ以上、好ましくは、４．０〜１０．０ｍｏｌ／Ｋｇであり、フッ素原子を含有する場合は水酸基濃度が２．００ｍｏｌ／Ｋｇ以上、好ましくは、３．０〜１０．０ｍｏｌ／Ｋｇである。
この値がこれらの数値を下回ると、アルカリ水溶液に十分に溶解しないという欠点がある。
【００１９】
上記水酸基濃度は、樹脂の原材料の種類と量を基にして、繰り返し単位質量当たりの水酸基含有量（水酸基数／繰り返し単位の質量）として計算できる。
【００２０】
また本発明で用いるポリベンゾオキサゾール前駆体は、そのポリベンゾオキサゾール前駆体から形成されるプリベーク膜の膜厚１０μｍあたりの波長３６５ｎｍの光線透過率が１％以上であることが好ましく、５％以上であることがより好ましく、１０％以上であることがさらに好ましい。ここで、この値が１％未満であると、高解像度で形状の良好なパターンを形成できる感光性樹脂組成物が得られにくい。特に好ましい透過率は、１０％〜８０％である。ポリベンゾオキサゾール前駆体の膜は、ポリベンゾオキサゾール前駆体を溶剤に溶解した状態で基板に塗布し、乾燥して膜とすることにより製造できる。ポリベンゾオキサゾール前駆体の膜の波長３６５ｎｍの光の透過率は、分光光度計（たとえば日立Ｕ−３４１０型、（株）日立製作所製）により測定することができる。測定時の膜厚が正確に１０μｍでない場合でも、ランベルトの法則に従い、１０μｍあたりの膜厚を換算することは可能である。
【００２１】
また、本発明の感光性樹脂組成物は、シリコンウエハ上に該組成物を用いて形成した塗膜を硬化（オキサゾールへ閉環）して得られるポリベンゾオキサゾール膜をその上に有するシリコンウエハの残留応力が２５℃で２５ＭＰａ以下となるものであることが好ましい。ここで、この値が２５ＭＰａを超えると、シリコンウエハの反り量やシリコンチップ内部の残留歪みが大きくなるという欠点がある。より好ましい残留応力は、０〜２０ＭＰａである。
なお、本発明における残留応力は、組成物を用いて、常温（２５℃）において、５〜８インチウエハ上に形成した硬化後の膜厚５〜２０μｍ、好ましくは約１０μｍの膜について、薄膜ストレス測定装置（たとえば、テンコール社製、ＦＬＸ−２３２０型）により測定することができる。
【００２２】
本発明の感光性樹脂組成物に用いられるポリベンゾオキサゾール前駆体は、前記一般式（２）で示される構造の繰り返し単位を有することが好ましく、これを全繰り返し単位の５０％以上がより好ましく、全繰り返し単位の８０％以上がさらに好ましく、約１００％であることが特に好ましい。
一般式（２）において、Ｘ及びＹはそれぞれ独立に、それらが結合するベンゼン環と共役しない２価の基であり、具体的には、カルボニル基、オキシ基、チオ基、スルフィニル基、スルホニル基、置換基を有してもよい炭素数１から５のアルキレン基、置換基を有してもよいイミノ基、置換基を有してもよいシリレン基、これらの基の組み合わせによってなる基などを例示することができる。
【００２３】
前記Ｘ及びＹの説明において述べた、各基中に有してもよい置換基としては、１価の置換基及び２価の置換基が挙げられ、具体的には、枝分かれがあってもよい、炭素数１〜１０のアルキル基、炭素数１〜１０のハロゲン（塩素、フッ素、沃素、臭素等）置換アルキル基、炭素数１〜１０のアルケニル基、炭素数１〜１０のアルキニル基、フェニル基、ベンジル基等の炭素数６〜２０の芳香族炭化水素基、炭素数１〜１０のアルキルオキシ基、炭素数１〜１０のハロゲン（塩素、フッ素、沃素、臭素等）置換アルキルオキシ基、シアノ基、ハロゲン原子（塩素、フッ素、沃素、臭素等）、ヒドロキシ基、アミノ基、アジド基、メルカプト基、各アルキル基の炭素数が１〜５のトリアルキルシリル基、炭素数２から５のアルキレン基、カルボニル基、カルボキシル基、イミノ基、オキシ基、チオ基、スルフィニル基、スルホニル基、各アルキル基の炭素数が１〜５のジアルキルシリレン基、さらにはこれらの組み合わせによってなる置換基などを例示することができる。中でも炭素数１〜５のアルキル基、同ハロゲン置換アルキル基、同アルキルオキシ基、同ハロゲン置換アルキルオキシ基、芳香族炭化水素基、炭素数２から３のアルキレン基がより好ましい。
【００２４】
Ｘ及びＹとしては、各々独立に単結合，Ｏ，ＣＨ_２，Ｃ＝Ｏ，Ｓｉ（ＣＨ_３）_２，Ｃ（ＣＨ_３）_２，Ｃ（ＣＦ_３）_２，Ｃ（ＣＨ_３）（ＣＦ_３），Ｓｉ（ＯＣＨ_３）_２，Ｃ（ＯＣＨ_３）_２，Ｃ（ＯＣＦ_３）_２，Ｃ（ＯＣＨ_３）（ＯＣＦ_３）、Ｓ、ＳＯ_２、ＣＨ（ＣＨ_３）、ＣＨ（ＣＦ_３）、ＣＨ（ＯＣＨ_３）、ＣＨ（ＯＣＦ_３）、ＳｉＨ（ＣＨ_３）及びＳｉＨ（ＯＣＨ_３）から選択される基であることがｉ線透過性やウエハ応力を低減できる上で好ましい。
【００２５】
Ｒ^２、Ｒ^３、Ｒ^４及びＲ^５で示される一価の基としては、水素原子、炭素数１〜１０のアルキル基、ＣＦ_３、ハロゲン原子、ＣＯＯＨ及びＯＨから選択される基であることがｉ線透過性やアルカリ水溶液に対する溶解性の点で好ましい。
【００２６】
本発明で用いるポリベンゾオキサゾール前駆体は、ジヒドロキシジアミンとジカルボン酸又はそれらの誘導体とを、必要に応じて用いる有機溶媒中で、反応させることにより合成することができる。
【００２７】
好ましいジヒドロキシジアミン成分として、例えば、
【化４】

【化５】

等が挙げられる。
【００２８】
また、本発明の範囲内において、例えば、３，３’−ジアミノ−４，４’−ジヒドロキシジフェニルエーテル、４，４’−ジアミノ−３，３’−ジヒドロキシジフェニルエーテル、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などのジアミンを用いることもできる。
【００２９】
好ましいジカルボン酸成分として、２つのカルボキシル基がパラ位に結合した
、ベンゼン環を１つ有するものが挙げられ、例えば、
【化６】

等が具体的に好ましいものとして挙げられる。
【００３０】
また、本発明の範囲内において、例えば、ジフェニルエーテル−４，４’−ジカルボン酸、ジフェニルエーテル−３，３’−ジカルボン酸、ジフェニルエーテル−３，４’−ジカルボン酸、ベンゾフェノン−４，４’−ジカルボン酸、ベンゾフェノン−３，４’−ジカルボン酸、ジフェニルスルホン−４，４’−ジカルボン酸、ジフェニルスルホン−３，４’−ジカルボン酸等や、
【００３１】
【化７】

【化８】

【化９】

等を用いることもできる。
【００３２】
前記反応に使用する有機溶媒としては、生成するポリベンゾオキサゾール前駆体を完全に溶解する極性溶媒が好ましく、例えば、Ｎ−メチル−２−ピロリドン、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジメチルホルムアミド、ジメチルスルホキシド、γ−ブチロラクトン等が挙げられる。
【００３３】
前記ポリベンゾオキサゾール前駆体は、例えば、ジカルボン酸ジハライド（クロライド、ブロマイド等）と、ジアミンとを反応させて得ることができる。
この場合、反応は脱ハロ酸触媒の存在下に、有機溶媒中で行うことが好ましい。
ジカルボン酸ジハライドとしては、ジカルボン酸ジクロリドが好ましい。ジカルボン酸ジクロリドは、ジカルボン酸と塩化チオニルを反応させて得ることができる。
【００３４】
本発明の感光性樹脂組成物は、前記ポリベンゾオキサゾール前駆体に感光性を付与することにより得られる。
感光性を付与する方法としては、例えば、光酸発生剤及び光塩基発生剤等の感光性付与剤を混合するなど既知の方法が挙げられる。
【００３５】
前記ポリベンゾオキサゾール前駆体の分子量に特に制限はないが、重量平均分子量で２０，０００〜１００，０００であることが好ましい。なお、分子量は、ゲルパーミエーションクロマトグラフィ法により測定し標準ポリスチレン換算することなどにより測定することができる。
【００３６】
本発明の感光性樹脂組成物は、前記ポリベンゾオキサゾール前駆体とともに、感光性とするために、一般に光により酸を発生する化合物や光により塩基を発生する化合物等の感光性付与剤を混合するが、光により酸を発生する化合物を用いることが好ましい。光により酸を発生する化合物とは、光照射により変化して酸を発生させ、光の照射部の現像液（アルカリ水溶液）への可溶性を増大させる機能を有するものである。その種類としては、ｏ−キノンジアジド化合物等の感光性キノンジアジド化合物、アリールジアゾニウム塩、ジアリールヨードニウム塩、トリアリールスルホニウム塩などが挙げられ、特に制限はないが、感光性キノンジアジド化合物が効果に優れ好ましい。感光性キノンジアジド化合物としては、米国特許２，７７２，９７２号などに記載されている１，２−ベンゾキノンジアジドあるいは１，２−ナフトキノンジアジド構造を有する公知の化合物が挙げられる。光により酸を発生する化合物は、現像後の膜厚及び感度の点から、ポリベンゾオキサゾール前駆体１００重量部に対して、好ましくは５〜１００重量部、より好ましくは１０〜４０重量部用いられる。
【００３７】
本発明の感光性樹脂組成物は、硬化膜の基板との接着性を高めるために、さらに有機シラン化合物、アルミキレート化合物、ケイ素含有ポリアミド酸などを含むことができる。
有機シラン化合物としては、例えば、γ−アミノプロピルトリメトキシシラン、γ−アミノプロピルトリエトキシシラン、ビニルトリエトキシシラン、γ−グリシドキシプロピルトリエトキシシラン、γ−メタクリロキシプロピルトリメトキシシランなどが挙げられる。アルミキレート化合物としては、例えば、トリス（アセチルアセトネート）アルミニウム、アセチルアセテートアルミニウムジイソプロピレートなどが挙げられる。
【００３８】
本発明の感光性樹脂組成物は、各成分を溶剤に溶解し溶液状態で得ることができる。
前記溶剤としては、例えば、Ｎ−メチル−２−ピロリドン、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、ジメチルスルホキシド、ヘキサメチルホスホルアミド、テトラメチレンスルホン、γ−ブチロラクトン、シクロヘキサノン、シクロペンタノン等の非プロトン性極性溶剤が単独で又は２種以上併用して用いられる。
【００３９】
本発明の感光性樹脂組成物は、浸漬法、スプレー法、スクリーン印刷法、回転塗布法等によってシリコンウエハー、金属基板、セラミック基板等の基材上に塗布され、溶剤の大部分を加熱乾燥することにより粘着性のない塗膜とすることができる。この塗膜の膜厚には特に制限はないが、回路特性等の点から、４〜５０μｍであることが好ましく、６〜４０μｍであることがより好ましく、１０〜４０μｍであることが特に好ましい。
【００４０】
また、本発明の感光性樹脂組成物は、低残留応力の膜を形成できるので、直径が３００ｍｍ（１２インチ）以上のシリコンウエハ等の大径のウエハへの適用に好適である。
この塗膜上に、所望のパターンが描かれたマスクを通して活性光線又は化学線を照射するなどしてパターン状に露光後、未露光部又は露光部を適当な現像液で現像して溶解し、除去することにより、所望のパターンを得ることができる。
【００４１】
本発明の感光性樹脂組成物は、ｉ線ステッパ等を用いたｉ線露光用に好適なものであるが、照射する活性光線又は化学線としては、ｉ線以外に、例えば、超高圧水銀灯を用いるコンタクト／プロキシミテイ露光機、ミラープロジェクション露光機、ｇ線ステッパ、その他の紫外線、可視光源、Ｘ線、電子線等も使用することができる。
【００４２】
現像液としては、アルカリ水溶液を用いることができ、前記アルカリ水溶液としては、例えば、水酸化ナトリウム、水酸化カリウム、ケイ酸ナトリウム、水酸化テトラメチルアンモニウム等の５重量％以下の水溶液、好ましくは１．５〜３．０重量％の水溶液などが用いられるが、より好ましい現像液は水酸化テトラメチルアンモニウムの１．５〜３．０重量％の水溶液である。
さらに上記現像液に界面活性剤等を添加して使用することもできる。これらはそれぞれ、現像液１００重量部に対して、好ましくは０．０１〜１０重量部、より好ましくは０．１〜５重量部の範囲で配合する。
【００４３】
現像後は、必要に応じて、水又は貧溶媒でリンスを行い、パターンを安定なものとすることもできる。得られたパターンは、加熱することによりパターン化された高耐熱性のポリベンゾオキサゾールとすることができる。
この時の加熱温度は、１００〜５００℃とすることが好ましく、２００〜４００℃とすることがより好ましい。この加熱温度が、１００℃未満であると、膜の機械特性及び熱特性が低下する傾向があり、５００℃を超えると、膜の機械特性及び熱特性が低下する傾向がある。
また、この時の加熱時間は、０．０５〜１０時間とすることが好ましい。この加熱時間が、０．０５時間未満であると、膜の機械特性及び熱特性が低下する傾向があり、１０時間を超えると、膜の機械特性及び熱特性が低下する傾向がある。
【００４４】
本発明の感光性樹脂組成物は、半導体装置や多層配線板等の電子部品に使用することができ、具体的には、半導体装置の表面保護膜や層間絶縁膜、多層配線板の層間絶縁膜等の形成に使用することができる。
本発明の電子部品は、前記組成物を用いて形成される表面保護膜や層間絶縁膜を有すること以外は特に制限されず、様々な構造をとることができる。
【００４５】
本発明の電子部品の一例として、半導体装置の製造工程の一例を以下に説明する。
図１は多層配線構造の半導体装置の製造工程図である。図において、回路素子を有するＳｉ基板等の半導体基板は、回路素子の所定部分を除いてシリコン酸化膜等の保護膜２で被覆され、露出した回路素子上に第１導体層が形成されている。前記半導体基板上にスピンコート法等で層間絶縁膜としての樹脂等の膜４が形成される（工程（ａ））。
【００４６】
次に塩化ゴム系、フェノールノボラック系等の感光性樹脂層５が前記層間絶縁膜４上にスピンコート法で形成され、公知の写真食刻技術によって所定部分の層間絶縁膜４が露出するように窓６Ａが設けられている（工程（ｂ））。
前記窓６Ａの層間絶縁膜４は、酸素、四フッ化炭素等のガスを用いるドライエッチング手段によって選択的にエッチングされ、窓６Ｂがあけられている。ついで窓６Ｂから露出した第１導体層３を腐食することなく、感光樹脂層５のみを腐食するようなエッチング溶液を用いて感光樹脂層５が完全に除去される（工程（ｃ））。
【００４７】
さらに公知の写真食刻技術を用いて、第２導体層７を形成させ、第１導体層３との電気的接続が完全に行われる（工程（ｄ））。
３層以上の多層配線構造を形成する場合は、上記の工程を繰り返して行い各層を形成することができる。
【００４８】
次に表面保護膜８が形成される。この図の例では、この表面保護膜を前記感光性樹脂組成物をスピンコート法にて塗布、乾燥し、所定部分に窓６Ｃを形成するパターンを描いたマスク上から光を照射した後アルカリ水溶液にて現像してパターンを形成し、加熱して樹脂膜とする。この樹脂膜は、導体層を外部からの応力、α線などから保護するものであり、得られる半導体装置は信頼性に優れる。
なお、上記例において、層間絶縁膜を本発明の感光性樹脂組成物を用いて形成することも可能である。
【００４９】
本発明の感光性樹脂組成物は、浸漬法、スプレー法、スクリーン印刷法、回転塗布法等によってシリコンウエハー、金属基板、セラミック基板等の基材上に塗布され、溶剤の大部分を加熱乾燥することにより粘着性のない塗膜とすることができる。この塗膜の膜厚には特に制限はないが、回路特性等の点から、４〜５０μｍであることが好ましく、６〜４０μｍであることがより好ましく、１０〜３０μｍであることが特に好ましく、１０〜２０μｍであることが極めて好ましい。
この塗膜上に、所望のパターンが描かれたマスクを通して活性光線又は化学線を照射する等してパターン状に露光後、露光部を適当なアルカリ現像液で現像して溶解し、除去することにより、所望のレリーフパターンを得ることができる。
【００５０】
【実施例】
以下、実施例により本発明を説明する。
合成例１〜５
（１）２００ｍｌの四つ口フラスコに表１に示すジカルボン酸０．０３モル、ピリジン４．７５ｇ（０．０６モル）、Ｎ，Ｎ’−ジメチルアセトアミド（ＤＭＡｃ）７０ｍｌを入れ、撹拌し、均一な溶液とした。この溶液の入ったフラスコを氷で冷却し、塩化チオニル８．５７ｇ（０．０７２モル）を１０分で滴下した。その後、室温で１時間撹拌し、酸クロライド溶液を得た。
【００５１】
（２）ポリベンゾオキサゾール前駆体の合成
別の２００ｍｌの四つ口フラスコに表１に示すジヒドロキシジアミン０．０３モル、ピリジン５．０６ｇ（０．０６４モル）、ＤＭＡｃ５０ｍｌを入れ、フラスコを氷で冷却（１０℃以下）撹拌しながら上記（１）で得られた酸クロライド溶液を１時間かけてゆっくりと滴下した。その後室温で１時間撹拌し、１リットルの水へ投入して析出したポリマーを濾取後二回洗浄し、真空乾燥した。
このポリマー粉末をγ−ブチロラクトン（γ−ＢＬ）に溶解し、粘度を８０ポイズに調節し、ポリベンゾオキサゾール前駆体溶液（Ｐ−１〜５）とした。
【００５２】
なお、粘度は、Ｅ型粘度計（東機産業（株）製、ＥＨＤ型）を使用し、温度が２５℃、回転数が２．５ｒｐｍで測定した。
また、得られたベンゾオキサゾール前駆体の溶液（Ｐ−１〜５）を乾燥させたものを、ＫＢｒ法により、赤外吸収スペクトル（日本電子（株）製、ＪＩＲ−１００型）を測定したところ、いずれも、１６００ｃｍ^−１付近にアミド基のＣ＝Ｏの吸収と、３３００ｃｍ^−１付近にＮ−Ｈの吸収が確認された。
【００５３】
実施例１〜３及び比較例１〜２
合成例１〜５で得られた各ポリベンゾオキサゾール前駆体（Ｐ−１〜５）の粉末１０ｇをγ−ブチロラクトン（γ−ＢＬ）１５ｇに溶解し、１，２−ナフトキノンジアジド２ｇを加え、均一な感光性樹脂組成物溶液を得た。
【００５４】
得られた感光性樹脂組成物溶液を、フィルタ濾過し、それぞれシリコンウエハ上に滴下スピンコートした。
次いで、ホットプレートを用いて、１００℃で１５０秒間加熱し、１５μｍの塗膜を形成した後、パターンマスクし、ｉ線ステッパで露光した。露光後、水酸化テトラメチルアンモニウム水溶液を用いて、パドル現像し、これを、４００℃で６０分間加熱して、ポリベンゾオキサゾールのレリーフパターンを得た。
【００５５】
合成例１〜５で得られた各ポリベンゾオキサゾール前駆体（Ｐ−１〜５）の透過率とシリコンウエハ上の残留応力及びレリーフパターンの解像度を以下の方法により評価し、これらの評価結果を表２に示した。
透過率は、得られた各ポリベンゾオキサゾール前駆体（Ｐ−１〜５）の樹脂溶液をスピンコートし、８５℃で２分間、さらに１０５℃で２分間乾燥して得られた塗膜（約１０μｍ）を、分光光度計で測定した。
【００５６】
残留応力は５インチウエハ上に、各組成物を用いて、スピンコートし、８５℃２分、１０５℃２分乾燥後、４００℃１時間熱処理し、硬化後の膜厚約１０μｍのポリベンゾオキサゾール膜を形成し、２５℃でテンコール社製応力測定装置（ＦＬＸ−２３２０型）で応力を測定した。
解像度は、スルホールテストパターンを用いて、現像可能なスルホールの最小の大きさとして評価した。
【００５７】
【表１】

【００５８】
【表２】

【００５９】
【発明の効果】
本発明の感光性樹脂組成物は、アルカリ水溶液による現像性に優れ、プリベーク膜における良好なｉ線透過性を有し、良好な解像度とパターンが得られ、かつ、シリコンウエハ上に形成した硬化後のポリベンゾオキサゾール膜が低残留応力となるものである。
【００６０】
また本発明のパターンの製造法によれば、アルカリ水溶液による現像性に優れ、ｉ線露光により高感度、高解像度で、形状も良好なパターンを製造でき、イミド化後に低応力で、耐熱性等を示すポリベンゾオキサゾールの膜を形成できる。さらに本発明の電子部品は、高解像度で、形状も良好なパターンであり、耐熱性に優れたポリベンゾオキサゾール膜を有し、しかも残留応力が極めて小さいため、信頼性に優れる。
【図面の簡単な説明】
【図１】 多層配線構造の半導体装置の製造工程図である。
【符号の説明】
１…半導体基板、２…保護膜、３…第１導体層、４…層間絶縁膜層、５…感光樹脂層、６Ａ、６Ｂ、６Ｃ…窓、７…第２導体層、８…表面保護膜層。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photosensitive resin composition using a polybenzoxazole precursor that imparts high i-line transmittance and low stress, and a semiconductor device using the same.
[0002]
[Prior art]
In recent years, in the semiconductor industry, an organic material having excellent heat resistance such as polyimide resin has been used as an interlayer insulating material, which has been conventionally performed using an inorganic material, taking advantage of its properties.
However, circuit pattern formation on a semiconductor integrated circuit or printed circuit board is complicated and diverse, such as film formation of a resist material on the surface of a base material, exposure to a predetermined location, removal of unnecessary portions by etching, etc., and cleaning of the substrate surface. Therefore, development of a heat-resistant photosensitive material that can be used by leaving a necessary portion of resist as an insulating material even after pattern formation by exposure and development is desired.
[0003]
As these materials, for example, heat-resistant photosensitive materials based on, for example, photosensitive polyimide and cyclized polybutadiene have been proposed. In particular, photosensitive polyimide has excellent heat resistance and can easily eliminate impurities. In particular, it is attracting attention from the point of being.
As such photosensitive polyimide, a system comprising a polyimide precursor and dichromate (Japanese Patent Publication No. 49-17374) was first proposed, but this material has practical photosensitivity. At the same time, it has advantages such as high film-forming ability, but lacks storage stability and has the disadvantage that chromium ions remain in the polyimide, and has not been put to practical use.
[0004]
In order to avoid such a problem, for example, a method in which a compound having a photosensitive group is mixed with a polyimide precursor (Japanese Patent Laid-Open No. 54-109828), a compound having a functional group and a photosensitive group in the polyimide precursor Methods for reacting with functional groups to give photosensitive groups (Japanese Patent Laid-Open Nos. 56-24343, 60-1000014, etc.) have been proposed. In addition, a photosensitive resin composition using a polybenzoxazole precursor has been proposed.
However, these photosensitive polyimide precursors and polybenzoxazole precursors use a basic skeleton for an aromatic monomer having excellent heat resistance and mechanical properties. Due to absorption of the polyimide precursor itself, transmission in the ultraviolet region is required. There was a problem that the photochemical reaction was low and the photochemical reaction in the exposed area could not be performed sufficiently effectively, and the sensitivity was low and the pattern shape deteriorated.
In recent years, with the higher integration of semiconductors, the processing rules are becoming smaller and higher resolution is required.
[0005]
For this reason, a 1: 1 projection exposure machine called a mirror projection and a reduced projection exposure machine called a stepper have been used from a conventional contact / proximity exposure machine using parallel rays.
The stepper utilizes a monochromatic light such as a high-power oscillation line of an ultra-high pressure mercury lamp or an excimer laser. Up to now, g-line steppers using visible light (wavelength: 435 nm) called g-line of ultra-high pressure mercury lamps have been the mainstream as steppers. It is necessary to shorten the wavelength.
Therefore, the exposure machine to be used is shifting from the g-line stepper (wavelength: 435 nm) to the i-line stepper (wavelength: 365 nm).
[0006]
However, conventional photosensitive polyimide base polymers designed for contact / proximity exposure machines, mirror projection projection exposure machines, and g-line steppers have low transparency, especially i-line (wavelength: wavelength) for the reasons described above. Since there is almost no transmittance at 365 nm), a decent pattern cannot be obtained with an i-line stepper.
In addition, a thicker surface protective polyimide film is required in response to LOC (Lead On Chip), which is a high-density mounting method for semiconductor elements, but in the case of a thick film, the permeability is low. The problem gets worse. For this reason, there is a strong demand for a photosensitive composition having a high i-line transmittance and a good pattern shape by an i-line stepper.
[0007]
Also, the diameter of silicon wafers that become substrates increases year by year, and due to the difference in thermal expansion coefficient between polyimide and polybenzoxazole and silicon wafers, warpage of silicon wafers formed with polyimide or polybenzoxazole as a surface protection film has been There is a problem of growing. Therefore, there is a strong demand for photosensitive polyimide and polybenzoxazole having lower thermal expansion than conventional polyimide and polybenzoxazole. In general, low thermal expansion can be achieved by making the molecular structure rigid. However, in the case of the rigid structure, the i-line is hardly transmitted, so that the photosensitive property is lowered.
[0008]
[Problems to be solved by the invention]
The present invention has excellent developability with an aqueous alkali solution, good i-line permeability in a pre-baked film, good resolution and pattern, and a cured polybenzoxazole film formed on a silicon wafer. A photosensitive resin composition having low residual stress is provided.
[0009]
In addition, the present invention is a polybenzoxazole film that has excellent developability with an alkaline aqueous solution, can produce a pattern with high sensitivity, high resolution, and good shape by i-line exposure, has low stress after imidization, and exhibits heat resistance, etc. The manufacturing method of the pattern which can form is provided.
In addition, the present invention provides a highly reliable electronic component having a high resolution, a good pattern, a polybenzoxazole film having excellent heat resistance, and extremely low residual stress. .
[0010]
[Means for Solving the Problems]
  The present invention provides a general formula(1)
[Chemical formula 2]

(In the formula, A is a tetravalent organic group having an aromatic ring, B is a divalent organic group, and two OH and two NH bonded to A are one OH and one NH. In the case where OH and NH in each pair are located at the ortho position of the aromatic ring, and the total number of aromatic rings contained in A and B is 3 or less) and do not contain a fluorine atom Is a polybenzoxazole precursor having a hydroxyl group concentration of 3.35 mol / Kg or more and containing a fluorine atom and having a hydroxyl group concentration of 2.00 mol / Kg or more, and is formed from the polybenzoxazole precursor. The present invention relates to a photosensitive resin composition comprising a polybenzoxazole precursor having a light transmittance of 365% per 10 μm film thickness of a coating film.
  As the polybenzoxazole precursor, the following general formula (2)
[Chemical Formula 3]

(In the formula, X and Y each independently represent a divalent group or a single bond that is not conjugated to each benzene ring to which each bond is bonded; ² , R ³ , R ⁴ And R ⁵ Each independently represents a monovalent group, and the bond represented by two arrows preferably indicates that they may be bonded in reverse.
[0011]
  Further, the present invention provides the photosensitive resin composition in which the residual stress of a silicon wafer having a polybenzoxazole film obtained by forming and curing a coating film using the composition is 25 MPa or less at 25 ° C.Related.
[0012]
  Moreover, this invention relates to the said photosensitive resin composition containing the compound which generate | occur | produces an acid by light.
  The present invention also provides the general formula(2)X and Y are each independently a single bond, O, CH₂, C = O, Si (CH₃)₂, C (CH₃)₂, C (CF₃)₂, C (CH₃) (CF₃), Si (OCH₃)₂, C (OCH₃)₂, C (OCF₃)₂, C (OCH₃) (OCF₃), S, SO₂, CH (CH₃), CH (CF₃), CH (OCH₃), CH (OCF₃), SiH (CH₃) And SiH (OCH₃) Selected from R)², R³, R⁴And R⁵Is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, CF₃And a photosensitive resin composition which is a group selected from halogen atoms, COOH and OH.
[0013]
Moreover, this invention relates to the manufacturing method of the pattern including the process of apply | coating and drying each said photosensitive resin composition on a support substrate, the process of exposing, the process of developing, and the process of heat-processing.
The present invention also relates to a pattern manufacturing method in which the exposing step is performed using i-line as an exposure light source.
[0014]
The present invention also relates to a method for producing a pattern in which the support substrate is a silicon wafer having a diameter of 300 mm or more.
The present invention also relates to an electronic component having a pattern layer obtained by the above-described manufacturing method.
Furthermore, the present invention is an electronic component in which the electronic component is a semiconductor device and the pattern layer is a surface protective film or an interlayer insulating film.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
  The photosensitive resin composition of the present invention has the general formulaPolybenzoxazole precursor having a repeating unit represented by (1), preferably having a repeating unit represented by the general formula (2)It contains a polybenzoxazole precursor.
  The polybenzoxazole precursor is one that can form polybenzoxazole by a ring-closing reaction. In the present invention, the general formulaThe repeating unit represented by (1), preferably the repeating unit represented by the general formula (2)It is what has.
[0016]
  General formula(1)A is a tetravalent organic group having an aromatic ring, and is generally a residue of dihydroxydiamine that reacts with a dicarboxylic acid to form a polybenzoxazole precursor structure. Two OHs and two NHs bonded to A form one OH and one NH, and each group of OH and NH is located at the ortho position of the aromatic ring.
  Examples of the tetravalent organic group having an aromatic ring represented by A include a group having 6 to 20 carbon atoms having at least one aromatic ring (benzene ring, naphthalene ring, etc.). It may have various substituents such as a group, a halogen atom, and a halogenated alkyl group.
[0017]
The divalent organic group represented by B is generally a residue of a dicarboxylic acid that reacts with dihydroxydiamine to form a polybenzoxazole precursor structure.
Examples of the divalent organic group having an aromatic ring represented by B include groups having 6 to 20 carbon atoms having at least one aromatic ring (benzene ring, naphthalene ring, etc.). You may have. It is preferable in terms of solubility in an alkaline aqueous solution that it has one aromatic ring.
[0018]
In the repeating unit represented by the general formula (1), the total number of aromatic rings contained in A and B is 3 or less. Here, when the number of aromatic rings is 4 or more, there is a disadvantage that it is difficult to achieve both low wafer stress and solubility in an alkaline aqueous solution.
The polybenzoxazole precursor in the present invention has a hydroxyl group concentration of 3.35 mol / Kg or more, preferably 4.0 to 10.0 mol / Kg when it does not contain a fluorine atom, and contains a fluorine atom. Has a hydroxyl group concentration of 2.00 mol / Kg or more, preferably 3.0 to 10.0 mol / Kg.
If this value is lower than these values, there is a drawback that it is not sufficiently dissolved in an alkaline aqueous solution.
[0019]
The hydroxyl group concentration can be calculated as the hydroxyl group content per repeating unit mass (the number of hydroxyl groups / the mass of repeating units) based on the type and amount of the raw material of the resin.
[0020]
The polybenzoxazole precursor used in the present invention preferably has a light transmittance of 1% or more at a wavelength of 365 nm per 10 μm film thickness of a pre-baked film formed from the polybenzoxazole precursor. More preferably, it is more preferably 10% or more. Here, when this value is less than 1%, it is difficult to obtain a photosensitive resin composition capable of forming a pattern with high resolution and good shape. A particularly preferable transmittance is 10% to 80%. A polybenzoxazole precursor film can be produced by applying a polybenzoxazole precursor dissolved in a solvent to a substrate and drying to form a film. The light transmittance at a wavelength of 365 nm of the polybenzoxazole precursor film can be measured with a spectrophotometer (for example, Hitachi U-3410 type, manufactured by Hitachi, Ltd.). Even when the film thickness at the time of measurement is not exactly 10 μm, it is possible to convert the film thickness per 10 μm according to Lambert's law.
[0021]
In addition, the photosensitive resin composition of the present invention is a residue of a silicon wafer having a polybenzoxazole film obtained by curing (ring-closing to oxazole) a coating film formed using the composition on a silicon wafer. It is preferable that the stress is 25 MPa or less at 25 ° C. Here, when this value exceeds 25 MPa, there is a drawback that the warpage amount of the silicon wafer and the residual strain inside the silicon chip increase. A more preferable residual stress is 0 to 20 MPa.
The residual stress in the present invention is a thin film stress for a film having a thickness of 5 to 20 μm after curing formed on a 5 to 8 inch wafer at room temperature (25 ° C.) using the composition, preferably about 10 μm. It can be measured with a measuring device (for example, FLX-2320 manufactured by Tencor).
[0022]
The polybenzoxazole precursor used in the photosensitive resin composition of the present invention preferably has a repeating unit having a structure represented by the general formula (2), more preferably 50% or more of all repeating units, 80% or more of the total repeating units is more preferable, and about 100% is particularly preferable.
In the general formula (2), X and Y are each independently a divalent group that is not conjugated with the benzene ring to which they are bonded, and specifically includes a carbonyl group, an oxy group, a thio group, a sulfinyl group, and a sulfonyl group. An alkylene group having 1 to 5 carbon atoms which may have a substituent, an imino group which may have a substituent, a silylene group which may have a substituent, a group formed by a combination of these groups, etc. It can be illustrated.
[0023]
Examples of the substituent that may be included in each group described in the description of X and Y include a monovalent substituent and a divalent substituent. Specifically, the substituent may be branched. An alkyl group having 1 to 10 carbon atoms, a halogen-substituted alkyl group having 1 to 10 carbon atoms (chlorine, fluorine, iodine, bromine, etc.), an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, phenyl An aromatic hydrocarbon group having 6 to 20 carbon atoms such as a benzyl group, an alkyloxy group having 1 to 10 carbon atoms, a halogen (chlorine, fluorine, iodine, bromine, etc.) substituted alkyloxy group having 1 to 10 carbon atoms, A cyano group, a halogen atom (chlorine, fluorine, iodine, bromine, etc.), a hydroxy group, an amino group, an azide group, a mercapto group, a trialkylsilyl group having 1 to 5 carbon atoms in each alkyl group, and having 2 to 5 carbon atoms Alkylene group, carboni Examples thereof include a group, a carboxyl group, an imino group, an oxy group, a thio group, a sulfinyl group, a sulfonyl group, a dialkylsilylene group having 1 to 5 carbon atoms in each alkyl group, and a substituent formed by a combination thereof. it can. Of these, an alkyl group having 1 to 5 carbon atoms, the same halogen-substituted alkyl group, the same alkyloxy group, the same halogen-substituted alkyloxy group, an aromatic hydrocarbon group, and an alkylene group having 2 to 3 carbon atoms are more preferable.
[0024]
X and Y are each independently a single bond, O, CH₂, C = O, Si (CH₃)₂, C (CH₃)₂, C (CF₃)₂, C (CH₃) (CF₃), Si (OCH₃)₂, C (OCH₃)₂, C (OCF₃)₂, C (OCH₃) (OCF₃), S, SO₂, CH (CH₃), CH (CF₃), CH (OCH₃), CH (OCF₃), SiH (CH₃) And SiH (OCH₃The group selected from (1) is preferable from the viewpoint of reducing i-line permeability and wafer stress.
[0025]
R², R³, R⁴And R⁵As the monovalent group represented by ## STR4 ## a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, CF₃And a group selected from a halogen atom, COOH and OH are preferable in terms of i-line permeability and solubility in an aqueous alkali solution.
[0026]
The polybenzoxazole precursor used in the present invention can be synthesized by reacting dihydroxydiamine and dicarboxylic acid or a derivative thereof in an organic solvent used as necessary.
[0027]
  Preferred dihydroxydiamine components include, for example,
[Formula 4]

[Chemical formula 5]

Etc.
[0028]
Further, within the scope of the present invention, for example, 3,3′-diamino-4,4′-dihydroxydiphenyl ether, 4,4′-diamino-3,3′-dihydroxydiphenyl ether, 2,2-bis (3-amino Diamines such as -4-hydroxyphenyl) hexafluoropropane can also be used.
[0029]
  As a preferred dicarboxylic acid component, two carboxyl groups are bonded in the para position
, One having one benzene ring, for example,
[Chemical 6]

And the like are specifically preferred.
[0030]
Further, within the scope of the present invention, for example, diphenyl ether-4,4′-dicarboxylic acid, diphenyl ether-3,3′-dicarboxylic acid, diphenyl ether-3,4′-dicarboxylic acid, benzophenone-4,4′-dicarboxylic acid Benzophenone-3,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, diphenylsulfone-3,4′-dicarboxylic acid, etc.
[0031]
[Chemical 7]

[Chemical 8]

[Chemical 9]

Etc. can also be used.
[0032]
The organic solvent used in the reaction is preferably a polar solvent that completely dissolves the resulting polybenzoxazole precursor, such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide. , Dimethyl sulfoxide, γ-butyrolactone, and the like.
[0033]
The polybenzoxazole precursor can be obtained, for example, by reacting dicarboxylic acid dihalide (chloride, bromide, etc.) with diamine.
In this case, the reaction is preferably performed in an organic solvent in the presence of a dehaloacid catalyst.
As the dicarboxylic acid dihalide, dicarboxylic acid dichloride is preferable. Dicarboxylic acid dichloride can be obtained by reacting dicarboxylic acid with thionyl chloride.
[0034]
The photosensitive resin composition of the present invention can be obtained by imparting photosensitivity to the polybenzoxazole precursor.
Examples of the method for imparting photosensitivity include known methods such as mixing a photosensitizer such as a photoacid generator and a photobase generator.
[0035]
Although there is no restriction | limiting in particular in the molecular weight of the said polybenzoxazole precursor, It is preferable that it is 20,000-100,000 in a weight average molecular weight. The molecular weight can be measured by measuring by gel permeation chromatography and converting to standard polystyrene.
[0036]
In order to make the photosensitive resin composition of the present invention photosensitive together with the polybenzoxazole precursor, generally a photosensitizer such as a compound that generates an acid by light or a compound that generates a base by light is mixed. However, it is preferable to use a compound that generates an acid by light. The compound that generates an acid by light has a function of generating an acid by being irradiated with light and increasing the solubility of the light irradiated portion in a developer (alkaline aqueous solution). Examples of the type include photosensitive quinonediazide compounds such as o-quinonediazide compounds, aryldiazonium salts, diaryliodonium salts, triarylsulfonium salts and the like. Although there is no particular limitation, photosensitive quinonediazide compounds are preferable because of their excellent effects. Examples of the photosensitive quinonediazide compound include known compounds having a 1,2-benzoquinonediazide or 1,2-naphthoquinonediazide structure described in US Pat. No. 2,772,972. The compound that generates an acid by light is preferably used in an amount of 5 to 100 parts by weight, more preferably 10 to 40 parts by weight, based on 100 parts by weight of the polybenzoxazole precursor, from the viewpoint of film thickness after development and sensitivity. .
[0037]
The photosensitive resin composition of the present invention can further contain an organic silane compound, an aluminum chelate compound, a silicon-containing polyamic acid, etc., in order to improve the adhesion of the cured film to the substrate.
Examples of the organic silane compound include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane. It is done. Examples of the aluminum chelate compound include tris (acetylacetonate) aluminum, acetylacetate aluminum diisopropylate, and the like.
[0038]
The photosensitive resin composition of the present invention can be obtained in a solution state by dissolving each component in a solvent.
Examples of the solvent include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, tetramethylene sulfone, γ-butyrolactone, cyclohexanone, cyclopenta Aprotic polar solvents such as non are used alone or in combination of two or more.
[0039]
The photosensitive resin composition of the present invention is applied onto a substrate such as a silicon wafer, a metal substrate, or a ceramic substrate by a dipping method, a spray method, a screen printing method, a spin coating method, or the like, and most of the solvent is heated and dried. By this, it can be set as the coating film without adhesiveness. Although there is no restriction | limiting in particular in the film thickness of this coating film, it is preferable that it is 4-50 micrometers from points, such as a circuit characteristic, It is more preferable that it is 6-40 micrometers, It is especially preferable that it is 10-40 micrometers.
[0040]
Further, since the photosensitive resin composition of the present invention can form a film having a low residual stress, it is suitable for application to a large-diameter wafer such as a silicon wafer having a diameter of 300 mm (12 inches) or more.
On this coating film, after exposure to a pattern such as irradiation with actinic rays or actinic radiation through a mask on which a desired pattern is drawn, the unexposed part or the exposed part is developed and dissolved with an appropriate developer, By removing, a desired pattern can be obtained.
[0041]
The photosensitive resin composition of the present invention is suitable for i-line exposure using an i-line stepper or the like, but as the active ray or actinic ray to be irradiated, in addition to i-line, for example, an ultra-high pressure mercury lamp is used. A contact / proximity exposure machine, a mirror projection exposure machine, a g-line stepper, other ultraviolet rays, a visible light source, an X-ray, an electron beam, etc. can be used.
[0042]
As the developer, an alkaline aqueous solution can be used. As the alkaline aqueous solution, for example, an aqueous solution of 5% by weight or less such as sodium hydroxide, potassium hydroxide, sodium silicate, tetramethylammonium hydroxide, preferably 1 An aqueous solution of 0.5 to 3.0% by weight or the like is used, but a more preferable developer is an aqueous solution of 1.5 to 3.0% by weight of tetramethylammonium hydroxide.
Further, a surfactant or the like can be added to the developer. Each of these is preferably blended in the range of 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the developer.
[0043]
After development, the pattern can be stabilized by rinsing with water or a poor solvent, if necessary. The obtained pattern can be made into a highly heat-resistant polybenzoxazole patterned by heating.
The heating temperature at this time is preferably 100 to 500 ° C, more preferably 200 to 400 ° C. When this heating temperature is less than 100 ° C., the mechanical properties and thermal properties of the film tend to deteriorate, and when it exceeds 500 ° C., the mechanical properties and thermal properties of the film tend to decrease.
Moreover, it is preferable that the heating time at this time shall be 0.05 to 10 hours. If this heating time is less than 0.05 hours, the mechanical properties and thermal properties of the film tend to deteriorate, and if it exceeds 10 hours, the mechanical properties and thermal properties of the film tend to deteriorate.
[0044]
The photosensitive resin composition of the present invention can be used for electronic components such as semiconductor devices and multilayer wiring boards. Specifically, surface protective films and interlayer insulating films of semiconductor devices, interlayer insulating films of multilayer wiring boards It can be used for the formation of etc.
The electronic component of the present invention is not particularly limited except that it has a surface protective film and an interlayer insulating film formed using the composition, and can have various structures.
[0045]
As an example of the electronic component of the present invention, an example of a manufacturing process of a semiconductor device will be described below.
FIG. 1 is a manufacturing process diagram of a semiconductor device having a multilayer wiring structure. In the figure, a semiconductor substrate such as a Si substrate having a circuit element is covered with a protective film 2 such as a silicon oxide film except for a predetermined portion of the circuit element, and a first conductor layer is formed on the exposed circuit element. . A film 4 such as a resin as an interlayer insulating film is formed on the semiconductor substrate by a spin coat method or the like (step (a)).
[0046]
Next, a photosensitive resin layer 5 such as chlorinated rubber or phenol novolac is formed on the interlayer insulating film 4 by a spin coating method so that a predetermined portion of the interlayer insulating film 4 is exposed by a known photolithography technique. A window 6A is provided (step (b)).
The interlayer insulating film 4 in the window 6A is selectively etched by dry etching means using a gas such as oxygen or carbon tetrafluoride to open the window 6B. Next, the photosensitive resin layer 5 is completely removed using an etching solution that corrodes only the photosensitive resin layer 5 without corroding the first conductor layer 3 exposed from the window 6B (step (c)).
[0047]
Furthermore, the second conductor layer 7 is formed using a known photolithography technique, and the electrical connection with the first conductor layer 3 is completely performed (step (d)).
When a multilayer wiring structure having three or more layers is formed, each layer can be formed by repeating the above steps.
[0048]
Next, the surface protective film 8 is formed. In the example of this figure, this surface protective film is applied with the photosensitive resin composition by a spin coat method, dried, and irradiated with light from a mask on which a pattern for forming a window 6C is formed at a predetermined portion, and then an alkaline aqueous solution. And developing to form a pattern and heating to form a resin film. This resin film protects the conductor layer from external stress, α rays, and the like, and the obtained semiconductor device is excellent in reliability.
In the above example, the interlayer insulating film can be formed using the photosensitive resin composition of the present invention.
[0049]
The photosensitive resin composition of the present invention is applied onto a substrate such as a silicon wafer, a metal substrate, or a ceramic substrate by a dipping method, a spray method, a screen printing method, a spin coating method, or the like, and most of the solvent is heated and dried. By this, it can be set as the coating film without adhesiveness. Although there is no restriction | limiting in particular in the film thickness of this coating film, it is preferable that it is 4-50 micrometers from points, such as a circuit characteristic, It is more preferable that it is 6-40 micrometers, It is especially preferable that it is 10-30 micrometers. It is very preferable that it is 10-20 micrometers.
After this pattern is exposed to this pattern by irradiating actinic rays or actinic rays through a mask on which a desired pattern is drawn, the exposed area is developed and dissolved with an appropriate alkaline developer and removed. Thus, a desired relief pattern can be obtained.
[0050]
【Example】
Hereinafter, the present invention will be described by way of examples.
Synthesis Examples 1-5
(1) A 200 ml four-necked flask was charged with 0.03 mol of the dicarboxylic acid shown in Table 1, 4.75 g (0.06 mol) of pyridine, 70 ml of N, N′-dimethylacetamide (DMAc), stirred and homogeneous Solution. The flask containing this solution was cooled with ice, and 8.57 g (0.072 mol) of thionyl chloride was added dropwise over 10 minutes. Then, it stirred at room temperature for 1 hour and obtained the acid chloride solution.
[0051]
(2) Synthesis of polybenzoxazole precursor
In another 200 ml four-necked flask, 0.03 mol of dihydroxydiamine shown in Table 1, 5.06 g (0.064 mol) of pyridine, and 50 ml of DMAc were placed, and the flask was cooled with ice (below 10 ° C.) and stirred (above) The acid chloride solution obtained in 1) was slowly added dropwise over 1 hour. Thereafter, the mixture was stirred at room temperature for 1 hour, poured into 1 liter of water, and the precipitated polymer was collected by filtration, washed twice, and vacuum-dried.
This polymer powder was dissolved in γ-butyrolactone (γ-BL), the viscosity was adjusted to 80 poise, and polybenzoxazole precursor solutions (P-1 to 5) were obtained.
[0052]
The viscosity was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., EHD type) at a temperature of 25 ° C. and a rotation speed of 2.5 rpm.
Moreover, when the infrared absorption spectrum (the JEOL Co., Ltd. make, JIR-100 type | mold) was measured for the thing which dried the solution (P-1-5) of the obtained benzoxazole precursor by KBr method. , Both are 1600cm^-1In the vicinity, C = O absorption of amide group and 3300 cm^-1Absorption of NH was confirmed in the vicinity.
[0053]
Examples 1-3 and Comparative Examples 1-2
10 g of each of the polybenzoxazole precursors (P-1 to 5) obtained in Synthesis Examples 1 to 5 was dissolved in 15 g of γ-butyrolactone (γ-BL), and 2 g of 1,2-naphthoquinonediazide was added. A photosensitive resin composition solution was obtained.
[0054]
The obtained photosensitive resin composition solution was filtered through a filter and each was spin-coated on a silicon wafer.
Next, using a hot plate, the film was heated at 100 ° C. for 150 seconds to form a 15 μm coating film, and then masked with a pattern and exposed with an i-line stepper. After exposure, paddle development was performed using an aqueous tetramethylammonium hydroxide solution, and this was heated at 400 ° C. for 60 minutes to obtain a relief pattern of polybenzoxazole.
[0055]
The transmittance of each polybenzoxazole precursor (P-1 to 5) obtained in Synthesis Examples 1 to 5, the residual stress on the silicon wafer, and the resolution of the relief pattern were evaluated by the following methods. It is shown in Table 2.
The transmittance was obtained by spin-coating the obtained resin solution of each polybenzoxazole precursor (P-1 to 5) and drying at 85 ° C. for 2 minutes and further at 105 ° C. for 2 minutes (about approx. 10 μm) was measured with a spectrophotometer.
[0056]
Residual stress was spin-coated using a composition on a 5-inch wafer, dried at 85 ° C. for 2 minutes and at 105 ° C. for 2 minutes, heat-treated at 400 ° C. for 1 hour, and cured to a polybenzoxazole having a thickness of about 10 μm. A film was formed, and the stress was measured at 25 ° C. with a stress measuring device (FLX-2320 type) manufactured by Tencor.
The resolution was evaluated as the smallest developable through hole size using the through hole test pattern.
[0057]
[Table 1]

[0058]
[Table 2]

[0059]
【The invention's effect】
The photosensitive resin composition of the present invention is excellent in developability with an alkaline aqueous solution, has good i-line permeability in a pre-baked film, has a good resolution and pattern, and has been formed on a silicon wafer after curing. The polybenzoxazole film has a low residual stress.
[0060]
Further, according to the pattern production method of the present invention, a pattern with excellent developability with an alkaline aqueous solution, high sensitivity, high resolution and good shape can be produced by i-line exposure, low stress after imidization, heat resistance, etc. A polybenzoxazole film can be formed. Furthermore, the electronic component of the present invention has a high resolution, a good pattern, a polybenzoxazole film having excellent heat resistance, and extremely low residual stress, so that it has excellent reliability.
[Brief description of the drawings]
FIG. 1 is a manufacturing process diagram of a semiconductor device having a multilayer wiring structure;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate, 2 ... Protective film, 3 ... 1st conductor layer, 4 ... Interlayer insulation film layer, 5 ... Photosensitive resin layer, 6A, 6B, 6C ... Window, 7 ... 2nd conductor layer, 8 ... Surface protective film layer.

Claims (9)

General formula (2)

(In the formula, X and Y each independently represent a divalent group or a single bond that is not conjugated to each bonded benzene ring, and R ² , R ³ , R ^4, and R ⁵ are each independently monovalent. And the bond indicated by two arrows indicates that they may be bonded in reverse), and when it does not contain a fluorine atom, the hydroxyl group concentration is 3.35 mol. The film thickness of the coating film formed from the polybenzoxazole precursor is a polybenzoxazole precursor having a hydroxyl group concentration of 2.00 mol / Kg or more when containing fluorine atoms. A photosensitive resin composition comprising a polybenzoxazole precursor having a light transmittance of 365% per 10 μm of 1% or more.   The photosensitive resin composition according to claim 1, wherein the residual stress of a silicon wafer having a polybenzoxazole film obtained by forming a coating film using the composition and curing is 25 MPa or less at 25 ° C. Furthermore, the photosensitive resin composition of Claim 1 or 2 containing the compound which generate | occur | produces an acid by light. X and Y in the general formula (2) are each independently a single bond, O, CH ₂ , C═O, Si (CH ₃ ) ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , C (CH ₃ ) (CF ₃ ), Si (OCH ₃ ) ₂ , C (OCH ₃ ) ₂ , C (OCF ₃ ) ₂ , C (OCH ₃ ) (OCF ₃ ), S, SO ₂ , CH (CH ₃ ), CH A group selected from (CF ₃ ), CH (OCH ₃ ), CH (OCF ₃ ), SiH (CH ₃ ) and SiH (OCH ₃ ), wherein R ² , R ³ , R ⁴ and R ⁵ are hydrogen The photosensitive resin composition according to claim 1, which is a group selected from an atom, an alkyl group having 1 to 10 carbon atoms, CF ₃ , a halogen atom, COOH and OH. The manufacturing method of the pattern including the process of apply | coating the photosensitive resin composition of any one of Claims 1-4 on a support substrate, drying, the process of exposing, the process of developing, and the process of heat-processing. The pattern manufacturing method according to claim 5 , wherein the exposing step is performed using i-line as an exposure light source. The method for producing a pattern according to claim 5 or 6, wherein the support substrate is a silicon wafer having a diameter of 300 mm or more. The electronic component which has a layer of the pattern obtained by the manufacturing method of any one of Claims 5-7 . The electronic component according to claim 8, wherein the electronic component is a semiconductor device, and the pattern layer is a surface protective film or an interlayer insulating film.

Images