JP2004239947A - Positive photoresist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photoresist composition excellent in sensitivity, resolution and depth of focus (DOF) characteristics for the manufacture of VLSIs which requires high resolution of a half micron meter or smaller than that, in particular, ≤0.35 μm. <P>SOLUTION: The positive photoresist composition comprises (A) an alkali-soluble novolac resin, (B) a non-benzophenone based naphthoquinone diazide sulfonate compound and (C) an alkali-soluble phenolic hydroxyl group-containing compound having ≤1,000 molecular weight. The component (A) contains a first alkali-soluble novolac resin synthesized by causing a di-functional phenol compound or its methylol product to react with a condensed product of m-cresol and aldehydes. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

〔式中、Ｒ^１〜Ｒ^８はそれぞれ独立に水素原子、ハロゲン原子、炭素原子数１〜６のアルキル基、炭素原子数１〜６のアルコキシル基、または炭素原子鎖３〜６のシクロアルキル基を表し；Ｒ^１０、Ｒ^１１はそれぞれ独立に水素原子または炭素原子数１〜６のアルキル基を表し；Ｒ^９が水素原子または炭素数１〜６のアルキル基の場合は、Ｑは水素原子、炭素数１〜６のアルキル基または下記化学式（ＩＩ）で表される残基
【化４】

（式中、Ｒ^１２およびＲ^１３はそれぞれ独立に水素原子、ハロゲン原子、炭素原子数１〜６のアルキル基、炭素原子数１〜６のアルコキシ基、または炭素原子数３〜６のシクロアルキル基を表し；ｃは１〜３の整数を示す）であり、ＱがＲ^９の末端と結合する場合は、ＱがＲ^９および、ＱとＲ^９との間の炭素原子とともに、炭素鎖３〜６のシクロアルキル基を表し；ａ、ｂは１〜３の整数を表し；ｄは０〜３の整数を表し；ｎは０〜３の整数を表す〕で表される化合物とナフトキノンジアジドスルホン酸化合物とのエステル化物であることを特徴とする第１〜１１のいずれかひとつの発明のポジ型ホトレジスト組成物である。
【００１０】
【発明の実施の形態】
［ポジ型ホトレジスト組成物］
＜（Ａ）成分＞
（Ａ）成分はアルカリ可溶性ノボラック樹脂であって、第一のアルカリ可溶性ノボラック樹脂を含んでいれば、特に限定せずに用いることができる。
第一のアルカリ可溶性ノボラック樹脂を用いることにより、溶解抑止効果に優れ、高残膜率、高コントラスト化が達成されたレジスト材料を調製することができる。
そして、超ＬＳＩの作製において、感度、解像性、および焦点深度幅（ＤＯＦ）特性に優れ、かつ形状のよいレジストパターンを形成できる。さらに種々のレジストパターン形成に対しても、形状の良いレジストパターンが得られる。
【００１１】
第一のアルカリ可溶性ノボラック樹脂は、例えば以下の様にして、ｍ−クレゾールとアルデヒド類とを反応させて得られる縮合体に（一次反応）、２官能性フェノール化合物を反応させて（二次反応）合成され得るものである。
【００１２】
アルデヒド類としては、ホルムアルデヒド（ホルマリン）、パラホルムアルデヒドやアセトアルデヒド、プロピルアルデヒド、ブチルアルデヒド、イソブチルアルデヒド、イソバレルアルデヒド、ヘキシルアルデヒド、オクチルアルデヒドなどのアルキルアルデヒド類；アクロレイン、クロトンアルデヒドなどの不飽和アルキルアルデヒド類；サリチルアルデヒド、パラヒドロキシベンズアルデヒドなどのヒドロキシベンズアルデヒド類；ベンズアルデヒド、フタルアルデヒドなどの芳香族アルデヒド類；グリオキサ−ル、グルタルアルデヒドなどのジアルデヒド類があげられるが、これらに限定されることはなく、単独および混合使用することができる。実用上特に有効なアルデヒド類としては、ホルムアルデヒド（ホルマリン）、パラホルムアルデヒドがあげられる。
【００１３】
２官能性フェノール化合物とは、フェノールのふたつのオルト位、およびひとつのパラ位のうちのひとつに置換基を有し、残りの２つに置換基が結合していないものをいう。
２官能性フェノール化合物は、分子量１００〜１５０程度のフェノール化合物が好ましく、例えばｐ−クレゾール、３，４−キシレノール等を挙げることができ、ｐ−クレゾールが安価であるので好ましい。
【００１４】
第一のアルカリ可溶性ノボラック樹脂は、公知のレゾールまたはノボラック樹脂の製造方法を用いて合成可能である。例えば以下の２種の方法によって得ることができる。
【００１５】
（ｉ）ｍ−クレゾールとアルデヒド類とを塩基性触媒の存在下に縮合反応させて縮合体を得た後（一次反応）、酸触媒存在下で２官能性フェノール化合物を反応させる方法（二次反応）。
この場合は、一次反応後の縮合体の表面にメチロール基が存在するため、後述する（ｉｉ）の方法と異なり、二次反応にあたって、さらなるアルデヒド類の添加は必要なく、２官能性フェノール化合物のみを用いて反応させて所望のアルカリ可溶性ノボラック樹脂を得ることができる。
【００１６】
一次反応時のアルデヒド類（Ａ１）とｍ−クレゾール（Ｍ）とのモル比（Ａ１）／（Ｍ）は（０．５〜３．０）／１とされる。０．５以上とすることにより、一次反応後の分子の密度が上がり、耐熱性が向上する。３．０以下とすることにより、一次反応後の遊離アルデヒド類の量を低減し、二次反応時の制御が容易となる。
【００１７】
塩基性触媒としては、トリメチルアミン、トリエチルアミン、トリブチルアミンなどの三級アミン類、ピリジン、ジメチルアミノピリジン、ピロリジノピリジンなどの芳香族アミン類、ジアザビシクロノネン（ＤＢＮ）、ジアザビシクロウンデセン（ＤＢＵ）などの脂環式アミン類を使用することができるが、特に限定されることなく、レゾール化反応を行うに十分な塩基性を有していれば使用することができる。
製造上特に有効なものは、三級アミン類であり、実用上トリエチルアミン、トリブチルアミンが最も好ましい。
【００１８】
塩基性触媒の使用量は特に限定されることはないが、系内のｐＨが７〜１２程度になる量であれば良い。実用上は、ｍ−クレゾールに対して５質量％から２０質量％が、反応の進行速度、制御の点から好ましい。
【００１９】
酸性触媒としては、例えば塩酸、硫酸、燐酸、ホウ酸などの無機酸類；蓚酸、酢酸、安息香酸、パラトルエンスルホン酸などの有機酸類があげられ、特に限定されることなく単独および混合して使用することができる。
好ましくは塩基性触媒との中和により水洗水に可溶な塩を生じ、モノマー除去時に分解、昇華などにより反応系から容易に除去できるものの使用が好ましい。
酸性触媒の使用量は、触媒の種類にもよるが、塩基触媒を中和し、反応系内のｐＨが１〜６の範囲になる量を設定することが好ましい。
【００２０】
具体的な操作としては、まず、反応容器に、ｍ−クレゾール、アルデヒド類、塩基性触媒を仕込んで一次反応を開始する。
反応温度や時間は、モノマ−の反応性、目的とする特性によって適宜設定できるが、安定かつ経済的に製造可能なレベルとして反応時間で０．５〜８時間、反応温度で４０〜１００℃が特に好ましい。
反応終了すると縮合体が得られる。そして、さらに反応器に２官能性フェノール化合物と酸性触媒を添加し、二次反応を行う。
二次反応の反応温度や時間は、製造される樹脂の特性やモノマ−の反応性により適宜選択できるが、安定かつ経済的に製造可能なレベルとして反応時間で１〜１０時間、反応温度で５０〜１５０℃が特に好ましい。
二次反応が終了すると、第一のアルカリ可溶性ノボラック樹脂とモノマー等を含む生成物が得られる。
【００２１】
なお、一次反応・二次反応時において、必要によって反応溶媒を添加使用することもできる。特に溶媒の種類は限定されないが、フェノ−ル樹脂を溶解する溶媒であれば使用できる。一例をあげるとγブチロラクトン、メチルエチルケトン、メチルイソブチルケトンなどのケトン類、ブタノ−ルなどのアルコ−ル類、エトキシエタノ−ルなどのエ−テルアルコ−ル類などが上げられる。
【００２２】
反応終了後、酸および塩基触媒を除去するために、水を加えて水洗を実施することが好ましい。
水洗水の量と回数は特に限定されないが、水洗回数は１−５回程度が残留触媒量と経済的な観点から特に好ましい。また、水洗温度は特に限定されないが、触媒種除去の効率と作業性の観点から４０〜９５℃で行うのが好ましい。水洗中、樹脂と水洗水の分離が悪い場合は、樹脂の粘度を低下させる溶媒の添加や水洗温度を上昇させることが効果的である。この溶媒は特に限定されないが、フェノ−ル樹脂を溶解して粘度を低下させるものであれば使用することができる。一例をあげると、アセトン、メチルエチルケトン、メチルイソブチルケトンなどのケトン類、メタノ−ル、エタノ−ル、ブタノ−ルなどのアルコ−ル類、エトキシエタノ−ルなどのエ−テルアルコ−ル類などが上げられる。
【００２３】
水洗終了後、常圧下および減圧下で脱水・脱モノマ−を行い、第一のアルカリ可溶性ノボラック樹脂を得ることができる。脱水・脱モノマ−の条件は限定されないが、得られたフェノ−ル樹脂の安定性（バラツキ）や粘度を考慮すると、減圧度は、０．１ｔｏｒｒから２００ｔｏｒｒ程度で行うのが特に好ましく、反応釜からの取り出し温度は、１５０〜２５０℃で行うのが特に好ましい。
【００２４】
（ｉｉ）ｍ−クレゾールとアルデヒド類とを酸触媒の存在下に縮合反応させて縮合体を得た後（一次反応）、酸触媒存在下で２官能性フェノール化合物またはそのメチロール体を反応させる方法（二次反応）。
この場合、一次反応で得られる縮合体の表面にメチロール基は存在しないため、二次反応においては、２官能性フェノール化合物およびアルデヒド類を用いるか、２官能性フェノール化合物のメチロール体を用い、酸触媒の存在下で反応させる。
一次反応時のアルデヒド類（Ａ１）とｍ−クレゾール（Ｍ）とのモル比（Ａ１）／（Ｍ）は、（０．５〜３．０）／１とされる。この範囲にすることにより二時反応時の制御が容易となり、好ましい。
【００２５】
酸触媒としては、前記（ｉ）の二次反応で用いるものと同様のものを用いることができる。
酸触媒の使用量は特に限定されることはないが樹脂の固形分に対して０．１質量％から２０質量％が、反応の進行速度、制御の点から好ましい。
この場合、酸触媒は一次反応時に仕込んだまま、二次反応でもそのまま反応に使用し得るので、二次反応時に追加しなくてもよいことが多い。
一次反応、二次反応の反応条件、操作は前記（ｉ）の場合と同様とし得る。
【００２６】
前記（ｉ）、（ｉｉ）において、縮合体のポリスチレン換算質量平均分子量（Ｍｗ）は、５００〜１５０００、特には１０００〜６０００の範囲であることが、良好なレジストパターンの形成やその他の特性に優れるという点で好ましい。
なお、ＭｗはＧＰＣ（ゲルパーミネーションクロマトグラフィ）によって測定することができる。
【００２７】
第一のアルカリ可溶性ノボラック樹脂は、Ｍｗ＝２０００〜２００００、特には３５００〜９０００であり、Ｍｗ／Ｍｎ（数平均分子量）が６．０以下、特には５．０以下であることが、良好なレジストパターンの形成やその他の特性に優れるという点で好ましい。
【００２８】
なお、合成に用いるｍ−クレゾール（Ｍ）と２官能性フェノール化合物またはそのメチロール体（Ｐ−２）の配合割合は、（Ｍ）／（Ｐ−２）＝（０．３〜０．７）／１（モル比）、特には（０．４〜０．６）／１（モル比）であることが、高コントラストのレジストパターン形成に優れる点で好ましい。
この配合量は、特に二次反応において、フェノール化合物として２官能性フェノール化合物またはそのメチロール体のみを用いる場合に好ましい。
【００２９】
また、二次反応時に、２官能性フェノール化合物とともに１官能性フェノール化合物を用いることもできる。これにより分散度の狭帯化という効果が得られる。
１官能性フェノール化合物とは、フェノールのふたつのオルト位およびひとつのパラ位のうちの２つに置換機を有し、残りの１つに置換基が結合していないものをいう。
前記（ｉｉ）の二次反応において、アルデヒド類を用いず、２官能性フェノール化合物のメチロール体を用いる場合は１官能性フェノール化合物としても、そのメチロール体を用いることが好ましい。
【００３０】
１官能性フェノール化合物としては、分子量１００〜１５０程度のフェノール化合物が好ましく、例えば、２，４−キシレノール、２，６−キシレノール、２，３，４−トリメチルフェノール、３，４，６−トリメチルフェノール、２，３，６−トリメチルフェノール等を挙げることができ、これらを１種または２種以上用いることができる。
中でも断面が矩形形状のレジストパターンが得られやすい点から、２，３，６−トリメチルフェノールが好ましい。
好ましいものはメチロール体の場合も同様である。
【００３１】
この場合の合成時のｍ−クレゾール（Ｍ）、２官能性フェノール化合物またはそのメチロール体（Ｐ−２）および１官能性フェノール化合物またはそのメチロール体（Ｐ−１）の配合割合は、
（Ｍ）／［（Ｐ−１）＋（Ｐ−２）］＝（０．４〜０．９）／１（モル比）かつ、
（Ｐ−２）／（Ｐ−１）＝（０．５〜０．９）／１（モル比）であることが、低分散度を得る点で好ましい。
特には前者が（０．５〜０．７）／１（モル比）、後者が（０．６〜０．８）／１（モル比）であることが、レジストパターン形状に優れる（レジストパターン断面形状が矩形に近い形状を呈する）の点で好ましい。
この配合割合は、二次反応に用いるフェノール化合物として、２官能性フェノール化合物またはそのメチロール体および１官能性フェノール化合物またはそのメチロール体のみを用いる場合に特に好ましい。
また、好ましくは後述する（Ａ）成分中の全フェノール系構成単位の組成割合を満足する範囲で、二次反応時に２官能性フェノール化合物またはそのメチロール体と１官能性フェノール化合物またはそのメチロール体以外の他のフェノール化合物を用いることもできる。
この場合は、第一のアルカリ可溶性ノボラック樹脂中においても、後述する（Ａ）成分中の全フェノール系構成単位の組成割合を満足する配合量となっていると好ましい。
【００３２】
また、第一のアルカリ可溶性ノボラック樹脂として、
一次反応、二次反応に用いるフェノール化合物として、ｍ−クレゾールと２官能性フェノール化合物のみを用いて合成した（Ａ−１）成分と、
一次反応、二次反応に用いるフェノール化合物として、ｍ−クレゾール、２官能性フェノール化合物および１官能性フェノール化合物のみを用いて合成した（Ａ−２）成分
とを混合して用いることにより、感度、解像性のバランスに優れたレジスト組成物を調製できるので好ましい。
このとき、（Ａ−１）成分と（Ａ−２）成分との配合割合は、（Ａ−１）／（Ａ−２）＝（０．３〜２．０）／１（質量比）、特には（０．４〜１．５）／１（質量比）であることが、特に感度、解像性のバランスに優れる点で好ましい。
【００３３】
また、（Ａ）成分においては、第一のアルカリ可溶性ノボラック樹脂以外のアルカリ可溶性ノボラック樹脂を配合することもできる。
この場合（Ａ）成分中、第一のアルカリ可溶性ノボラック樹脂の含有量は、６０質量％以上、好ましくは７０質量％以上であることが、本願発明の効果を得るために好ましい。
第一のアルカリ可溶性ノボラック樹脂以外に配合可能なものは、特に制限されるものでなく、ポジ型ホトレジスト組成物において被膜形成物質として通常用いられ得るものの中から、任意に１種または２種以上選択して用いることができる。
【００３４】
例えば、フェノール類（フェノール、ｍ−クレゾール、ｐ−クレゾール、キシレノール、トリメチルフェノールなど）と、アルデヒド類（ホルムアルデヒド、ホルムアルデヒド前駆体、２−ヒドロキシベンズアルデヒド、３−ヒドロキシベンズアルデヒド、４−ヒドロキシベンズアルデヒドなど）またはケトン類（メチルエチルケトン、アセトンなど）とを、酸性触媒存在下に縮合させて得られる第一のアルカリ可溶性ノボラック樹脂以外のノボラック樹脂等が挙げられる。
【００３５】
また、第一のアルカリ可溶性ノボラック樹脂を含有する（Ａ）成分中の全フェノール系構成単位が、ｍ−クレゾール構成単位と、２官能性フェノール化合物構成単位と、１官能性フェノール化合物構成単位のみからなる場合、レジストの特性のバランスに優れる点で好ましい。
なお、１官能性フェノール化合物構成単位は、第一のアルカリ可溶性ノボラック樹脂に含まれていてもよいし、その他のアルカリ可溶性ノボラック樹脂に含まれていてもよい。また、他のアルカリ可溶性ノボラック樹脂が、２官能性フェノール化合物構成単位を含んでいてもよい。
すなわち、この「（Ａ）成分中の全フェノール系構成単位」とは、第一のアルカリ可溶性ノボラック樹脂のみならず、他のアルカリ可溶性ノボラック樹脂に含まれるフェノール系構成単位全てを示す。
それらの含有割合は、ｍ−クレゾール構成単位／２官能性フェノール化合物構成単位／１官能性フェノール化合物構成単位＝（３５〜４０）／（３５〜５０）／（１０〜２５）（モル比）であることがレジストパターン上部が丸味を帯びることなく、断面が矩形形状のレジストパターンが得られやすい点から好ましい。
なお、第一のアルカリ可溶性ノボラック樹脂中のフェノール系構成単位が、この組成を満足するとより好ましい。
【００３６】
また、この全フェノール系構成単位が、ｍ−クレゾール構成単位と、２官能性フェノール化合物構成単位と、１官能性フェノール化合物構成単位と、その他のフェノール系構成単位からなる場合もある。
この場合、それらの含有割合は、ｍ−クレゾール構成単位／２官能性フェノール化合物構成単位／１官能性フェノール化合物構成単位／その他のフェノール系構成単位＝（３５〜４０）／（３５〜５０）／（１０〜２５）／（５〜１０）（モル比）であることがレジスト特性のバランスに優れる点から好ましい。
その他のフェノール化合物構成単位としては、特に限定するものではないが、例えばｍ−エチルフェノール、３，５−ジメチルフェノール、３，５−ジエチルフェノール、ジヒドロキシベンゼン等が挙げられる。
また、その他のフェノール化合物構成単位は、上述の様に第一のアルカリ可溶性ノボラック樹脂に含まれていてもよいし、他のアルカリ可溶性ノボラック樹脂に含まれていてもよい。
なお、第一のアルカリ可溶性ノボラック樹脂のフェノール系構成単位が、この組成を満足するとより好ましい。
【００３７】
＜（Ｂ）成分＞
（Ｂ）成分は、非ベンゾフェノン系のナフトキノンジアジドスルホン酸エステル化物である。
（Ｂ）成分は、特に制限はなく、ｉ線用ポジ型ホトレジスト組成物の感光剤として公知のものを利用できる。
特に、前記一般式（Ｉ）で表される化合物の中から選ばれる少なくとも１種の化合物とナフトキノンジアジドスルホン酸化合物とのエステル化物が、高感度、高解像性に優れ、好ましい。
中でも、リニア型４〜５核体のフェノール骨格を有するエステル化物が好ましい。
この一般式（Ｉ）に該当するフェノール化合物としては、トリス（４−ヒドロシキフェニル）メタン、ビス（４−ヒドロキシ−３−メチルフェニル）−２−ヒドロキシフェニルメタン、ビス（４−ヒドロキシ−２，３，５−トリメチルフェニル）−２−ヒドロキシフェニルメタン、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）−４−ヒドロキシフェニルメタン、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）−３−ヒドロキシフェニルメタン、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）−２−ヒドロキシフェニルメタン、ビス（４−ヒドロキシ−２，５−ジメチルフェニル）−４−ヒドロキシフェニルメタン、ビス（４−ヒドロキシ−２，５−ジメチルフェニル）−３−ヒドロキシフェニルメタン、ビス（４−ヒドロキシ−２，５−ジメチルフェニル）−２−ヒドロキシフェニルメタン、ビス（４−ヒドロキシ−３，５−ジメチルフェニル）−３，４−ジヒドロキシフェニルメタン、ビス（４−ヒドロキシ−２，５−ジメチルフェニル）−３，４−ジヒドロキシフェニルメタン、ビス（４−ヒドロキシ−２，５−ジメチルフェニル）−２，４−ジヒドロキシフェニルメタン、ビス（４−ヒドロキシフェニル）−３−メトキシ−４−ヒドロキシフェニルメタン、ビス（５−シクロヘキシル−４−ヒドロキシ−２−メチルフェニル）−４−ヒドロキシフェニルメタン、ビス（５−シクロヘキシル−４−ヒドロキシ−２−メチルフェニル）−３−ヒドロキシフェニルメタン、ビス（５−シクロヘキシル−４−ヒドロキシ−２−メチルフェニル）−２−ヒドロキシフェニルメタン、ビス（５−シクロヘキシル−４−ヒドロキシ−２−メチルフェニル）−３，４−ジヒドロキシフェニルメタンなどのトリスフェノール型化合物；
【００３８】
２，４−ビス（３，５−ジメチル−４−ヒドロキシベンジル）−５−ヒドロキシフェノール、２，６−ビス（２，５−ジメチル−４−ヒドロキシベンジル）−４−メチルフェノール等のリニア型３核体フェノール化合物；１，１−ビス〔３−（２−ヒドロキシ−５−メチルベンジル）−４−ヒドロキシ−５−シクロヘキシルフェニル〕イソプロパン、ビス［２，５−ジメチル−３−（４−ヒドロキシ−５−メチルベンジル）−４−ヒドロキシフェニル］メタン、ビス［２，５−ジメチル−３−（４−ヒドロキシベンジル）−４−ヒドロキシフェニル］メタン、ビス［３−（３，５−ジメチル−４−ヒドロキシベンジル）−４−ヒドロキシ−５−メチルフェニル］メタン、ビス［３−（３，５−ジメチル−４−ヒドロキシベンジル）−４−ヒドロキシ−５−エチルフェニル］メタン、ビス［３−（３，５−ジエチル−４−ヒドロキシベンジル）−４−ヒドロキシ−５−メチルフェニル］メタン、ビス［３−（３，５−ジエチル−４−ヒドロキシベンジル）−４−ヒドロキシ−５−エチルフェニル］メタン、ビス［２−ヒドロキシ−３−（３，５−ジメチル−４−ヒドロキシベンジル）−５−メチルフェニル］メタン、ビス［２−ヒドロキシ−３−（２−ヒドロキシ−５−メチルベンジル）−５−メチルフェニル］メタン、ビス［４−ヒドロキシ−３−（２−ヒドロキシ−５−メチルベンジル）−５−メチルフェニル］メタン、ビス［２，５−ジメチル−３−（２−ヒドロキシ−５−メチルベンジル）−４−ヒドロキシフェニル］メタン等のリニア型４核体フェノール化合物；
２，４−ビス［２−ヒドロキシ−３−（４−ヒドロキシベンジル）−５−メチルベンジル］−６−シクロヘキシルフェノール、２，４−ビス［４−ヒドロキシ−３−（４−ヒドロキシベンジル）−５−メチルベンジル］−６−シクロヘキシルフェノール、２，６−ビス［２，５−ジメチル−３−（２−ヒドロキシ−５−メチルベンジル）−４−ヒドロキシベンジル］−４−メチルフェノール等のリニア型５核体フェノール化合物等のリニア型ポリフェノール化合物；
ビス（２，３，４−トリヒドロキシフェニル）メタン、ビス（２，４−ジヒドロキシフェニル）メタン、２，３，４−トリヒドロキシフェニル−４’−ヒドロキシフェニルメタン、２−（２，３，４−トリヒドロキシフェニル）−２−（２’，３’，４’−トリヒドロキシフェニル）プロパン、２−（２，４−ジヒドロキシフェニル）−２−（２’，４’−ジヒドロキシフェニル）プロパン、２−（４−ヒドロキシフェニル）−２−（４’−ヒドロキシフェニル）プロパン、２−（３−フルオロ−４−ヒドロキシフェニル）−２−（３’−フルオロ−４’−ヒドロキシフェニル）プロパン、２−（２，４−ジヒドロキシフェニル）−２−（４’−ヒドロキシフェニル）プロパン、２−（２，３，４−トリヒドロキシフェニル）−２−（４’−ヒドロキシフェニル）プロパン、２−（２，３，４−トリヒドロキシフェニル）−２−（４’−ヒドロキシ−３’，５’−ジメチルフェニル）プロパンなどのビスフェノール型化合物；
１−［１−（４−ヒドロキシフェニル）イソプロピル］−４−［１，１−ビス（４−ヒドロキシフェニル）エチル］ベンゼン、１−［１−（３−メチル−４−ヒドロキシフェニル）イソプロピル］−４−［１，１−ビス（３−メチル−４−ヒドロキシフェニル）エチル］ベンゼン、などの多核枝分かれ型化合物；
１，１−ビス（４−ヒドロキシフェニル）シクロヘキサンなどの縮合型フェノール化合物などが挙げられる。
これらは１種または２種以上組み合わせて用いることができる。
【００３９】
前記一般式（Ｉ）で表される化合物のフェノール性水酸基の全部または一部をナフトキノンジアジドスルホン酸エステル化する方法は、常法により行うことができる。
例えば、ナフトキノンジアジドスルホニルクロライドを前記一般式（Ｉ）で表される化合物と縮合させることにより得ることができる。
具体的には、例えば前記一般式（Ｉ）で表される化合物と、ナフトキノン−１，２−ジアジド−４（または５）−スルホニルクロライドとを、ジオキサン、ｎ−メチルピロリドン、ジメチルアセトアミド、テトラヒドロフラン等の有機溶媒に所定量溶解し、ここにトリエチルアミン、トリエタノールアミン、ピリジン、炭酸アルカリ、炭酸水素アルカリ等の塩基性触媒を１種以上を加えて反応させ、得られた生成物を水洗、乾燥して調製することができる。
【００４０】
（Ｂ）成分の配合量は、（Ａ）成分と（Ｃ）成分との合計量に対し１０〜６０質量％の範囲が好ましく、より好ましくは２０〜５０質量％の範囲である。（Ｂ）成分の配合量を下限値以上とすることにより、パターンに忠実な画像が得られ、転写性も向上する。
一方、（Ｂ）成分の配合量を上限値以下とすることにより、感度劣化と形成されるレジスト膜の均質性の低下が抑制され、解像性の劣化も抑制される。
【００４１】
＜（Ｃ）成分＞
（Ｃ）成分は、分子量が１０００以下のアルカリ可溶性のフェノール性水酸基含有化合物である。（Ｃ）成分を配合することにより、感度が向上するという効果が得られる。
（Ｃ）成分の質量平均分子量は１０００以下、好ましくは８００以下、実質的には２００以上、好ましくは３００以上であることが、前記効果の点から好ましい。
（Ｃ）成分は特に制限はなく、ｉ線用ポジ型ホトレジスト組成物の増感剤（感度向上剤）として公知のものを利用できる。
特に、前記一般式（Ｉ）で表されるフェノール化合物が用いられる。
具体的には、例えば前記（Ｂ）成分において例示した、フェノール化合物のナフトキノンジアジドエステル化物において用いられる、フェノール化合物を好適に用いることができる。
【００４２】
また、下記一般式（ＩＩＩ）で表される、特許第２６２９９９０号公報に記載の化合物も好ましい。
【００４３】
【化５】

【００４４】
（式中、Ｚ^１、Ｚ^２、Ｚ^３、Ｚ^４、Ｚ^５、Ｚ^６、Ｚ^７、Ｚ^８およびＺ^９はそれぞれ、アルキル基、水素原子、ハロゲン原子または−ＯＨ基を表すが、これらのうち少なくとも１つは−ＯＨ基であり、そしてＲ^２１、Ｒ^２２、Ｒ^２３、Ｒ^２４、Ｒ^２５およびＲ^２６はそれぞれ、水素原子、アルキル基、アルケニル基、シクロアルキル基またはアリール基を表す。）
【００４５】
中でも、２，６−ビス（２，５−ジメチル−４−ヒドロキシベンジル）−４−メチルフェノール、１，１−ビス（４−ヒドロキシフェニル）ベンゼン、４−（３−ヒドロキシスピロ［５，６，７，８，１０ａ，８ａ−ヘキサヒドロキサンテン−９，１’−シクロヘキサン］−１０ａ−イル）ベンゼン−１，３−ジオール、４−（２，３−ジヒドロキシスピロ［５，６，７，８，１０ａ，８ａ−ヘキサヒドロサンテン−９，１’−シクロヘキサン］−１０ａ−イル）ベンゼン−１，２，３−トリオールなどが好ましい。
【００４６】
（Ｃ）成分の含有量は（Ａ）成分に対して５〜５０質量％が好ましく、より好ましくは１０〜３５質量％の範囲とされる。この範囲とすることにより、露光余裕度、解像性、焦点深度幅特性をさらに向上させ、感度にも優れるので、より好ましい。
【００４７】
本発明のポジ型ホトレジスト組成物は、前記（Ａ）成分、（Ｂ）成分、（Ｃ）成分を、有機溶剤に溶解して用いることが好ましい。
溶剤の例としては、従来のポジ型ホトレジスト組成物に用いられる溶剤を挙げることができ、例えばアセトン、メチルエチルケトン、シクロヘキサノン、メチルイソアミルケトン、２−ヘプタノン等のケトン類；エチレングリコール、プロピレングリコール、ジエチレングリコール、エチレングリコールモノアセテート、プロピレングリコールモノアセテート、ジエチレングリコールモノアセテート、あるいはこれらのモノメチルエーテル、モノエチルエーテル、モノプロピルエーテル、モノブチルエーテルまたはモノフェニルエーテル等の多価アルコール類およびその誘導体；ジオキサンのような環式エーテル類；および乳酸エチル、酢酸メチル、酢酸エチル、酢酸ブチル、ピルビン酸メチル、ピルビン酸エチル、メトキシプロピオン酸メチル、エトキシプロピオン酸エチル等のエステル類を挙げることができる。これらは単独で用いてもよいし、２種以上を混合して用いてもよい。とくにアセトン、メチルエチルケトン、シクロヘキサノン、メチルイソアミルケトン、２−ヘプタノン等のケトン類；乳酸エチル、酢酸メチル、酢酸エチル、酢酸ブチル、ピルビン酸メチル、ピルビン酸エチル、メトキシプロピオン酸メチル、エトキシプロピオン酸エチル等のエステル類が好ましい。
有機溶剤の使用量はポジ型ホトレジスト組成物を基板に塗布できる濃度とされ、特に限定するものではない。
【００４８】
＜その他の添加剤等＞
本発明の組成物には、さらに必要に応じて、相容性のある添加物、ハレーション防止のための紫外線吸収剤、例えば２，２’，４，４’−テトラヒドロキシベンゾフェノン、４−ジメチルアミノ−２’，４’−ジヒドロキシベンゾフェノン、５−アミノ−３−メチル−１−フェニル−４−（４−ヒドロキシフェニルアゾ）ピラゾール、４−ジメチルアミノ−４’−ヒドロキシアゾベンゼン、４−ジエチルアミノ−４’−エトキシアゾベンゼン、４−ジエチルアミノアゾベンゼン、クルクミンなど、またストリエーション防止のための界面活性剤、例えばフロラードＦＣ−４３０、ＦＣ４３１（商品名、住友３Ｍ（株）製）、Ｒ−０８、ＸＲ−１０４（商品名、大日本インキ化学工業（株）社製）エフトップＥＦ１２２Ａ、ＥＦ１２２Ｂ、ＥＦ１２２Ｃ、ＥＦ１２６（商品名、トーケムプロダクツ（株）製）等のフッ素系界面活性剤などを本発明の目的に支障のない範囲で添加含有させることができる。
【００４９】
［レジストパターンの形成方法］
以下に、レジストパターンの好適な形成方法の一例を示す。
まず、上述の本発明のポジ型ホトレジスト組成物を、スピンナー等で基板に塗布して塗膜を形成する。基板としてはシリコン基板が好ましい。
ついで、この塗膜が形成された基板を例えば加熱処理（プリベーク）して残存溶媒を除去し、レジスト被膜を形成する。
さらに、前記レジスト被膜に対し、マスクパターンが描かれたマスク（レチクル）を用いて選択的露光を行う。
光源としては、微細なパターンを形成するためにｉ線（３６５ｎｍ）を用いることが好ましい。
次いで、選択的露光後のレジスト被膜に対し、加熱処理（ポストエクスポージャーベーク：ＰＥＢ）を施す。
前記ＰＥＢ後のレジスト被膜に対し、現像液、例えば１〜１０質量％テトラメチルアンモニウムヒドロキシド水溶液のようなアルカリ水溶液を用いた現像処理を施すと、露光部分が溶解除去され、レジストパターンが形成される。
さらに、レジストパターン表面に残った現像液を純水などのリンス液で洗い落とすことによりレジストパターンを形成できる。
【００５０】
【実施例】
次に実施例を示して本発明をさらに詳細に説明するが、本発明は以下の実施例に限定されるものではない。
【００５１】
［ポジ型ホトレジスト組成物の評価方法］
下記の実施例または比較例のポジ型ホトレジスト組成物について下記の諸物性（１）〜（５）の評価方法を以下に示す。
【００５２】
（１）感度
試料をスピンナーを用いてシリコンウェーハ上に塗布し、これをホットプレート上で９０℃、９０秒間乾燥（プリベーク）して膜厚１．０５μｍのレジスト膜を得た。この膜にＬ＆Ｓが１：１の０．３５μｍレジストパターン対応のマスク（レチクル）を介して縮小投影露光装置ＮＳＲ−２２０５ｉ１４Ｅ（ニコン社製、ＮＡ＝０．５７）を用いて、０．１秒から０．０１秒間隔で露光したのち、１１０℃、６０秒間のＰＥＢ（露光後加熱）処理を行い、２．３８質量％テトラメチルアンモニウムヒドロキシド水溶液で２３℃にて６０秒間現像し、３０秒間水洗して乾燥したとき、０．３５μｍレジストパターンのラインアンドスペース幅が１：１に形成される露光時間（Ｅｏｐ）を感度としてミリ秒（ｍｓ）単位で表した。
【００５３】
（２−１）焦点深度幅特性［孤立ラインパターン（Ｉｓｏ）］
縮小投影露光装置ＮＳＲ−２２０５ｉ１４Ｅ（ニコン社製、ＮＡ＝０．５７）を用いて、Ｅｏｐ〔マスクパターンの設定寸法（線幅０．３５μｍ、Ｌ＆Ｓが１：１）が忠実に再現されるのに要する露光量〕を基準露光量とし、その露光量において、焦点を適宜上下にずらし、露光、現像を行って得られたＩｓｏ（線幅０．３５μｍ）のＳＥＭ写真の観察を行った。そのＳＥＭ写真より０．３５μｍの矩形のレジストパターンが設定寸法の±１０％の範囲で得られる焦点のずれの最大値（μｍ）を焦点深度幅特性とした。
【００５４】
（２−２）焦点深度幅特性［ラインアンドスペースパターン（Ｌ＆Ｓ）］
縮小投影露光装置ＮＳＲ−２２０５ｉ１４Ｅ（ニコン社製、ＮＡ＝０．５７）を用いて、Ｅｏｐ〔マスクパターンの設定寸法（線幅０．３５μｍ、Ｌ＆Ｓが１：１）が忠実に再現されるのに要する露光量〕を基準露光量とし、その露光量において、焦点を適宜上下にずらし、露光、現像を行って得られたＬ＆Ｓ（線幅０．３５μｍ、Ｌ＆Ｓが１：１）のＳＥＭ写真の観察を行った。そのＳＥＭ写真より０．３５μｍの矩形のレジストパターンが設定寸法の±１０％の範囲で得られる焦点のずれの最大値（μｍ）を焦点深度幅特性とした。
【００５５】
（２−３）焦点深度幅特性［ドットパターン］
縮小投影露光装置ＮＳＲ−２２０５ｉ１４Ｅ（ニコン社製、ＮＡ＝０．５７）を用いて、Ｅｏｐ〔マスクパターンの設定寸法（線幅０．３５μｍ、Ｌ＆Ｓが１：１）が忠実に再現されるのに要する露光量〕を基準露光量とし、その露光量において、焦点を適宜上下にずらし、露光、現像を行って得られたドットパターン（直径０．５μｍ）のＳＥＭ写真の観察を行った。そのＳＥＭ写真より直径０．５μｍのレジストパターンが設定寸法の±１０％の範囲で得られる焦点のずれの最大値（μｍ）を焦点深度幅特性とした。
【００５６】
（２−４）焦点深度幅特性［ホールパターン］
縮小投影露光装置ＮＳＲ−２２０５ｉ１４Ｅ（ニコン社製、ＮＡ＝０．５７）を用いて、Ｅｏｐ〔マスクパターンの設定寸法（線幅０．３５μｍ、Ｌ＆Ｓが１：１）が忠実に再現されるのに要する露光量〕を基準露光量とし、その露光量において、焦点を適宜上下にずらし、露光、現像を行って得られたホールパターン（直径０．５μｍ）のＳＥＭ写真の観察を行った。そのＳＥＭ写真より直径０．５μｍのレジストパターンが設定寸法の±１０％の範囲で得られる焦点のずれの最大値（μｍ）を焦点深度幅特性とした。
【００５７】
（２−５）焦点深度幅特性［トレンチターン（スリットパターン）］
縮小投影露光装置ＮＳＲ−２２０５ｉ１４Ｅ（ニコン社製、ＮＡ＝０．５７）を用いて、Ｅｏｐ〔マスクパターンの設定寸法（線幅０．３５μｍ、Ｌ＆Ｓが１：１）が忠実に再現されるのに要する露光量〕を基準露光量とし、その露光量において、焦点を適宜上下にずらし、露光、現像を行って得られたトレンチパターン（幅０．４μｍ）のＳＥＭ写真の観察を行った。そのＳＥＭ写真より幅０．４μｍのレジストパターンが設定寸法の±１０％の範囲で得られる焦点のずれの最大値（μｍ）を焦点深度幅特性とした。
【００５８】
［合成例１］
冷却器と攪拌器付きの反応容器に、ｍ−クレゾール３６．０ｇ（０．３３モル）、３７質量％ホルマリン３７．８ｇ（０．４７モル）、トリエチルアミン１．７８ｇを仕込み、徐々に昇温して、８０℃で２時間還流させた。
室温まで冷却した後、シュウ酸を加えて中和し、ｐ−クレゾール７２．０ｇ（０．６７モル）、シュウ酸２ｇを添加し、反応温度を１００℃で８時間反応を行った。
【００５９】
反応終了後、７０℃まで冷却してアセトン５００ｇ、純水６００ｇを添加して約７０℃で攪拌、静置した。
分離水を除去した後、アセトン５００ｇ、純水６００ｇを使用して、再度水洗操作を行った。
その後、常圧下で内温１４０℃まで脱水し、さらに６０ｔｏｒｒの減圧下で１９５℃まで脱水、脱モノマーを行い、Ｍｗ＝３７５０、Ｍｗ／Ｍｎ＝４．４のノボラック樹脂１（Ａ１）を得た。
【００６０】
［合成例２］
冷却器と攪拌器付きの反応容器に、ｍ−クレゾール４３．２ｇ（０．４モル）、３７質量％ホルマリン４５．４ｇ（０．５６モル）、トリエチルアミン２．１４ｇを仕込み、徐々に昇温して、８０℃で２時間還流させた。
室温まで冷却した後、シュウ酸を加えて中和し、ｐ−クレゾール２７．０（０．２５モル）ｇ、２，３，６−トリメチルフェノール４７．６ｇ（０．３５モル）、シュウ酸２ｇを添加し、反応温度を１００℃で８時間反応を行った。
反応終了後、７０℃まで冷却してアセトン５００ｇ、純水６００ｇを添加して約７０℃で攪拌、静置した。
分離水を除去した後、アセトン５００ｇ、純水６００ｇを使用して、再度水洗操作を行った。
その後、常圧下で内温１４０℃まで脱水し、さらに６０ｔｏｒｒの減圧下で１９５℃まで脱水、脱モノマーを行い、Ｍｗ＝４０５０、Ｍｗ／Ｍｎ＝４．６のノボラック樹脂２（Ａ２）を得た。
【００６１】
［合成例３］（合成例１において、第６の発明を適用し、合成した例）
冷却器と攪拌器付きの反応容器に、ｍ−クレゾール３６．０ｇ（０．３３モル）、３７質量％ホルマリン１８．７ｇ（０．２３モル）、シュウ酸２．０ｇを仕込み、徐々に昇温して、１００℃で８時間還流させた。
室温まで冷却した後、ｐ−クレゾール７２．０ｇ（０．６７モル）、３７質量％ホルマリン３８．０ｇを添加し、反応温度を１００℃で８時間反応を行った。
反応終了後、７０℃まで冷却してアセトン５００ｇ、純水６００ｇを添加して約７０℃で攪拌、静置した。
分離水を除去した後、アセトン５００ｇ、純水６００ｇを使用して、再度水洗操作を行った。
その後、常圧下で内温１４０℃まで脱水し、さらに６０ｔｏｒｒの減圧下で１９５℃まで脱水、脱モノマーを行い、Ｍｗ＝３８００、Ｍｗ／Ｍｎ＝４．８のノボラック樹脂３（Ａ３）を得た。
【００６２】
［合成例４］（合成例１において、第７の発明を適用し、合成した例）
冷却器と攪拌器付きの反応容器に、ｍ−クレゾール３６．０ｇ（０．３３モル）、３７質量％ホルマリン１８．７ｇ（０．２３モル）、シュウ酸２．０ｇを仕込み、次いでγ−ブチロラクトンを加えて４０質量％濃度に調製し、これを徐々に昇温して、１００℃で８時間還流させた。
室温まで冷却した後、２，６−ジメチロール−ｐ−クレゾール１１２．１ｇ（０．６７モル）を含有する４０質量％濃度のγ−ブチロラクトン溶液を添加し、反応温度を１００℃で２時間反応を行った。
反応終了後、７０℃まで冷却してアセトン５００ｇ、純水６００ｇを添加して約７０℃で攪拌、静置した。
分離水を除去した後、アセトン５００ｇ、純水６００ｇを使用して、再度水洗操作を行った。
その後、常圧下で内温１４０℃まで脱水し、さらに６０ｔｏｒｒの減圧下で１９５℃まで脱水、脱モノマーを行い、Ｍｗ＝４２００、Ｍｗ／Ｍｎ＝５．０のノボラック樹脂４（Ａ４）を得た。
【００６３】
［比較合成例１］
合成例１において、ｍ−クレゾールの代わりにｐ−クレゾールを用いてレゾール反応（一次反応）を行い、ｐ−クレゾールの代わりにｍ−クレゾールを用いてノボラック樹脂の合成を行った以外は合成例１と同様にして、ノボラック樹脂（Ｍｗ＝４２００、Ｍｗ／Ｍｎ＝３．８）を合成した。
【００６４】
［比較合成例２］
合成例２において、ｍ−クレゾールの代わりにｐ−クレゾールを用いてレゾール反応（一次反応）を行い、ｐ−クレゾールの代わりにｍ−クレゾールを用いてノボラック樹脂の合成を行った以外は合成例２と同様にして、ノボラック樹脂（Ｍｗ＝４５００、Ｍｗ／Ｍｎ＝４．８）を合成した。
【００６５】
［比較合成例３］
合成例１と同様の配合量でｍ−クレゾール、ｐ−クレゾールを同時に仕込み、酸触媒を用いて常法によりノボラック樹脂の合成反応を行い、ノボラック樹脂（Ｍｗ＝３８００、Ｍｗ／Ｍｎ＝５．７）を合成した。
【００６６】
［比較合成例４］
合成例２と同様の配合量でｍ−クレゾール、ｐ−クレゾール、２，３，６−トリメチルフェノールを同時に仕込み、酸触媒を用いて常法によりノボラック樹脂の合成反応を行い、ノボラック樹脂（Ｍｗ＝４０００、Ｍｗ／Ｍｎ＝６．７）を合成した。
【００６７】
［実施例１］
下記の（Ａ）〜（Ｆ）を２−ヘプタノンに溶解し、室温（２３℃）で粘度６ｃｐに調整した後、これを孔径０．２μｍのメンブランフィルターを用いてろ過し、ポジ型ホトレジスト組成物を調製した。
【００６８】
（Ａ）成分： １００質量部
［Ａ１／Ａ２＝１／２（質量比）］
（Ｂ）成分： ５２質量部
［Ｂ１／Ｂ２＝５／１（質量比）］
（Ｃ）成分： ３０質量部
［Ｃ１／Ｃ２＝１／１（質量比）］
（Ｄ）成分： ２．７３質量部
［Ｄ１］
（Ｅ）成分： ０．９２質量部
［Ｅ１］
（Ｆ）成分： ０．０８質量部
［ＸＲ−１０４］
【００６９】
なお、前記各記号は以下の化合物を示す。
Ｂ１：２，６−ビス［２，５−ジメチル−３−（２−ヒドロキシ−５−メチルベンジル）−４−ヒドロキシベンジル］−４−メチルフェノール １モルと、ナフトキノン−１，２−ジアジド−５−スルホニルクロライド（以下 ５−ＮＱＤと示す）２モルとのエステル化反応生成物
Ｂ２：２，６−ビス［２，５−ジメチル−３−（２−ヒドロキシ−５−メチルベンジル）−４−ヒドロキシベンジル］−４−メチルフェノール １モルと、５−ＮＱＤ３モルとのエステル化反応生成物
Ｃ１：２，６−ビス［２，５−ジメチル−４−ヒドロキシベンジル］−４−メチルフェノール
Ｃ２：１，１−ビス（４−ヒドロキシフェニル）シクロヘキサン
Ｄ１：１，４−ビス［１−（２−メチル−４−ヒドロキシ−５−シクロヘキシルフェニル）イソプロピル］ベンゼン
Ｅ１：ｐ−トルエンスルホン酸クロリド
【００７０】
［実施例２〜３］、［比較例１〜３］
実施例１の（Ａ）成分を下記表１に示したように代えた以外は実施例１と同様にしてポジ型ホトレジスト組成物を調製した
【００７１】
【表１】

【００７２】
［実施例４］
下記（Ａ）〜（Ｅ）を２−ヘプタノンに溶解し、室温（２３℃）で粘度５．５ｃｐに調整した後、これを孔径０．２μｍのメンブランフィルターを用いてろ過し、ポジ型ホトレジスト組成物を調製した。
（Ａ）成分： １００質量部
［Ａ１／Ａ２／Ａ５＝４／５／６（質量比）］
（Ｂ）成分： ５２質量部
［Ｂ１／Ｂ２＝５／１（質量比）］
（Ｃ）成分： ３０質量部
［Ｃ３］
（Ｄ）成分： １．３７質量部
［Ｄ１］
（Ｆ）成分： ０．０８質量部
［Ｒ−０８］
【００７３】
なお、前記記号は以下の化合物を示す。
Ａ５：ｍ−クレゾール／ｐ−クレゾール／２，３，５−トリメチルフェノール＝４０／３５／２５（モル比）の混合フェノールに対し、ホルムアルデヒド／サリチルアルデヒド＝１０／１（モル比）の混合フェノールを用い、塩酸触媒を用いて常法により合成したノボラック樹脂（Ｍｗ＝３５００）
Ｃ３：４−（３−ヒドロキシスピロ［５，６，７，８，１０ａ，８ａ−ヘキサヒドロキサンテン−９，１’−シクロヘキサン］−１０ａ−イル）ベンゼン−１，３−ジオール）
【００７４】
［比較例４］
実施例１の（Ｂ）成分を２，３，４−トリヒドロキシベンゾフェノン１モルと１，２−ナフトキノンジアジド−５−スルホン酸クロライド２モルとのエステル化物に代えた以外は、実施例１と同様にしてポジ型ホトレジスト組成物を調製した。
【００７５】
［比較例５］
実施例１の（Ｃ）成分を配合しなかった以外は、実施例１と同様にしてポジ型ホトレジスト組成物を調製した。
【００７６】
表２に各実施例、比較例のポジ型ホトレジスト組成物の評価結果を示した。
【００７７】
【表２】

【００７８】
表２に示した結果から明らかな様に、実施例のポジ型ホトレジスト組成物は、感度が実用可能な値を示し、焦点深度幅特性も各パターンにおいて、バランスがとれていた。また、解像性も良好であった。そして、スカムの発生も少なく、レジストパターン形状も良好であった。
【００７９】
【発明の効果】
ハーフミクロン以下、特に０．３５μｍ以下の高解像性を必要とする超ＬＳＩの作製において、感度、解像性、および焦点深度幅（ＤＯＦ）特性に優れるポジ型ホトレジスト組成物を提供できる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a positive photoresist composition and a method for forming a resist pattern.
[0002]
[Prior art]
In the production of VLSI which requires high resolution of half micron or less, particularly 0.35 μm or less, a resist pattern having excellent sensitivity, resolution, and depth of focus (DOF) characteristics and a good shape is formed. There is a need for a photoresist composition that can be used.
In recent years, attention has been focused on the manufacture of high value-added logic ICs, but the wiring circuits of the logic ICs are complicated. That is, while the DRAM has many portions where the line and space of the wiring pattern are regularly formed (so-called L & S), the logic IC has a portion where the line and space of the wiring pattern is irregular or a dot pattern or the like. Includes many wiring patterns other than line patterns.
[0003]
Therefore, in a photolithography process using a photoresist composition, various resist patterns such as a dot pattern, a line-and-space pattern (L & S), an isolated line pattern (Iso), a hole pattern, and a trench pattern (slit pattern) are formed in good shape. It is desired to form.
However, it has been difficult to form all of these various resist patterns with a good shape in forming an ultrafine pattern of half a micron or less, particularly 0.35 μm or less.
[0004]
In particular, conventional positive photoresist compositions tend to be inferior in depth of focus (DOF) characteristics when forming Iso or dot patterns.
Further, when a hole pattern, a trench pattern (slit pattern), and the like are formed, there is a problem that the film is largely reduced in an unexposed portion, and it is difficult to form a resist pattern having an excellent vertical shape.
[0005]
With the above background, in the field of forming ultra-fine patterns of half micron or less, particularly 0.35 μm or less, sensitivity, resolution, and depth of focus (DOF) characteristics are excellent, and various resist patterns are formed in good shape. There has been a demand for a positive photoresist composition that can be formed.
[0006]
As a resist material having excellent resolution, for example, a positive photoresist composition described in JP-A-6-167805, JP-A-9-110762, JP-A-9-114093 and the like can be mentioned.
These achieve high resolution by blending a photosensitive component (naphthoquinonediazidesulfonic acid ester) having a specific skeleton.
And, although it shows very excellent characteristics for forming L & S, it has been difficult to apply it to the field of forming resist patterns such as dot patterns, Iso, hole patterns, trench patterns (slit patterns).
[0007]
[Patent Document 1]
JP-A-6-167805
[Patent Document 2]
JP-A-9-110762
[Patent Document 3]
JP-A-9-114093
[0008]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been described in connection with the manufacture of a super LSI that requires a high resolution of half a micron or less, particularly 0.35 μm or less, in terms of sensitivity, resolution, and depth of focus (DOF). An object of the present invention is to provide a positive photoresist composition having excellent characteristics.
More preferably, in the formation of various resist patterns such as a dot pattern, a line and space pattern (L & S), an isolated line pattern (Iso), a hole pattern, and a trench pattern (slit pattern), the shape is good for any of them. An object of the present invention is to provide a positive photoresist composition capable of forming a resist pattern.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a first invention comprises (A) an alkali-soluble novolak resin,
(B) a non-benzophenone-based naphthoquinonediazidesulfonic acid ester, and
(C) In a positive photoresist composition containing an alkali-soluble phenolic hydroxyl group-containing compound having a molecular weight of 1,000 or less,
The positive component, wherein the component (A) contains a first alkali-soluble novolak resin that can be synthesized by reacting a condensate of m-cresol and an aldehyde with a bifunctional phenol compound or a methylol derivative thereof. It is a type photoresist composition.
According to a second invention, in the first alkali-soluble novolak resin, the mixing ratio of m-cresol (M) and a bifunctional phenol compound or a methylol derivative (P-2) thereof is (M) / (P- 2) The positive photoresist composition of the first invention, characterized in that: (0.3 to 0.7) / 1 (molar ratio).
A third invention is characterized in that the first alkali-soluble novolak resin can be synthesized by reacting the condensate with a bifunctional phenol compound and a monofunctional phenol compound, or a methylol thereof. The positive photoresist composition according to the first aspect of the present invention.
According to a fourth invention, in the first alkali-soluble novolak resin, m-cresol (M), a bifunctional phenol compound or a methylol derivative thereof (P-2) and a monofunctional phenol compound or a methylol derivative thereof (P- The compounding ratio of 1) is
(M) / [(P-1) + (P-2)] = (0.4 to 0.9) / 1 (molar ratio) and (P-2) / (P-1) = (0. 5 to 0.9) / 1 (molar ratio).
In a fifth aspect, the first alkali-soluble novolak resin is:
To a condensate which can be synthesized by a condensation reaction between m-cresol and an aldehyde in the presence of a basic catalyst,
The invention according to any one of the first to fourth aspects, characterized in that it can be synthesized by reacting a bifunctional phenol compound or a bifunctional phenol compound and a monofunctional phenol compound in the presence of an acid catalyst. Is a positive photoresist composition.
In a sixth aspect, the first alkali-soluble novolak resin is:
To a condensate that can be synthesized by a condensation reaction between m-cresol and an aldehyde in the presence of an acid catalyst,
Any of the above first to fourth compounds, which can be synthesized by reacting a bifunctional phenol compound or a bifunctional phenol compound and a monofunctional phenol compound in the presence of an aldehyde and an acid catalyst. A positive photoresist composition according to one aspect of the present invention.
In a seventh aspect, the first alkali-soluble novolak resin is:
To a condensate that can be synthesized by a condensation reaction between m-cresol and an aldehyde in the presence of an acid catalyst,
The methylol of a bifunctional phenol compound, or the methylol of a bifunctional phenol compound and the methylol of a monofunctional phenol compound, which can be synthesized by reacting in the presence of an acid catalyst. A positive photoresist composition according to any one of the inventions 1 to 4.
An eighth invention provides the positive photoresist composition according to any one of the first to seventh inventions,
A positive photoresist composition, wherein all the phenolic constituent units of the component (A) are composed of m-cresol constituent units, bifunctional phenol compound constituent units, and monofunctional phenol compound constituent units. .
According to a ninth invention, in all the phenolic structural units, m-cresol structural unit / 2 bifunctional phenol compound structural unit / 1 monofunctional phenol compound structural unit = (35-40) / (35-50) / (10 To 25) (molar ratio) in the positive photoresist composition according to the eighth aspect of the present invention.
A tenth invention provides a positive photoresist composition according to any one of claims 1 to 7,
All the phenolic structural units of the component (A) are characterized by comprising m-cresol structural units, bifunctional phenolic compound structural units, monofunctional phenolic compound structural units, and other phenolic structural units. Is a positive photoresist composition.
According to an eleventh aspect, in the above-mentioned all phenolic structural units, m-cresol structural unit / 2 bifunctional phenolic compound structural unit / 1 monofunctional phenolic compound structural unit / other phenolic structural units = (35 to 40) / ( The positive photoresist composition according to the tenth aspect of the present invention, wherein the composition is (35-50) / (10-25) / (5-10) (molar ratio).
According to an eleventh aspect, the component (B) is represented by the following general formula (I)
Embedded image

[Wherein, R ¹ ~ R ⁸ Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; ¹⁰ , R ¹¹ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; ⁹ Is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, Q is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a residue represented by the following chemical formula (II)
Embedded image

(Where R ¹² And R ^Thirteen Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; Q represents R) ⁹ Q is R ⁹ And Q and R ⁹ A and b represent an integer of 1 to 3; d represents an integer of 0 to 3; n represents an integer of 0 to 3 together with a carbon atom between The positive photoresist composition according to any one of the first to eleventh aspects of the present invention is an esterified product of a compound represented by the following formula: and a naphthoquinonediazidosulfonic acid compound.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
[Positive photoresist composition]
<(A) component>
The component (A) is an alkali-soluble novolak resin, and can be used without any particular limitation as long as it contains the first alkali-soluble novolak resin.
By using the first alkali-soluble novolak resin, it is possible to prepare a resist material having an excellent dissolution inhibiting effect, a high residual film ratio and a high contrast.
Then, in the manufacture of an VLSI, a resist pattern having excellent sensitivity, resolution, and depth of focus (DOF) characteristics and having a good shape can be formed. Furthermore, a resist pattern having a good shape can be obtained for various resist pattern formations.
[0011]
The first alkali-soluble novolak resin is obtained by reacting a condensate obtained by reacting m-cresol with an aldehyde (primary reaction) and a bifunctional phenol compound (secondary reaction), for example, as follows. ) Can be synthesized.
[0012]
Aldehydes include alkylaldehydes such as formaldehyde (formalin), paraformaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, isobutyraldehyde, isovaleraldehyde, hexylaldehyde, and octylaldehyde; unsaturated alkylaldehydes such as acrolein and crotonaldehyde Hydroxybenzaldehydes such as salicylaldehyde and parahydroxybenzaldehyde; aromatic aldehydes such as benzaldehyde and phthalaldehyde; dialdehydes such as glyoxal and glutaraldehyde, but are not limited thereto. And mixed can be used. Aldehydes particularly effective for practical use include formaldehyde (formalin) and paraformaldehyde.
[0013]
The bifunctional phenol compound is a compound having a substituent at one of two ortho positions and one para position of phenol, and a substituent is not bonded to the other two positions.
As the bifunctional phenol compound, a phenol compound having a molecular weight of about 100 to 150 is preferable, and examples thereof include p-cresol and 3,4-xylenol.
[0014]
The first alkali-soluble novolak resin can be synthesized using a known resol or novolak resin production method. For example, it can be obtained by the following two methods.
[0015]
(I) A method of reacting m-cresol with an aldehyde in the presence of a basic catalyst to obtain a condensate (primary reaction), followed by reacting a bifunctional phenol compound in the presence of an acid catalyst (secondary reaction) reaction).
In this case, since a methylol group is present on the surface of the condensate after the primary reaction, unlike the method (ii) described later, no additional aldehyde is required for the secondary reaction, and only the bifunctional phenol compound is used. And a desired alkali-soluble novolak resin can be obtained.
[0016]
The molar ratio (A1) / (M) between the aldehydes (A1) and m-cresol (M) at the time of the primary reaction is (0.5 to 3.0) / 1. By setting it to 0.5 or more, the density of molecules after the primary reaction increases, and the heat resistance improves. When the content is 3.0 or less, the amount of free aldehydes after the primary reaction is reduced, and control during the secondary reaction becomes easy.
[0017]
Examples of the basic catalyst include tertiary amines such as trimethylamine, triethylamine and tributylamine, aromatic amines such as pyridine, dimethylaminopyridine and pyrrolidinopyridine, diazabicyclononene (DBN), and diazabicycloundecene (DBU). Alicyclic amines such as a) can be used, but are not particularly limited as long as they have sufficient basicity to carry out the resolving reaction.
Particularly effective ones in production are tertiary amines, and practically, triethylamine and tributylamine are most preferable.
[0018]
The amount of the basic catalyst used is not particularly limited, but may be any amount as long as the pH in the system becomes about 7 to 12. Practically, 5 to 20% by mass based on m-cresol is preferred from the viewpoint of the reaction progress rate and control.
[0019]
Examples of the acidic catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and boric acid; and organic acids such as oxalic acid, acetic acid, benzoic acid, and paratoluenesulfonic acid. can do.
It is preferable to use a salt which is soluble in water for washing by neutralization with a basic catalyst and which can be easily removed from the reaction system by decomposition, sublimation or the like at the time of removing the monomer.
The amount of the acidic catalyst used depends on the type of the catalyst, but is preferably set to an amount that neutralizes the base catalyst and makes the pH in the reaction system in the range of 1 to 6.
[0020]
As a specific operation, first, m-cresol, aldehydes, and a basic catalyst are charged into a reaction vessel to start a primary reaction.
The reaction temperature and time can be appropriately set depending on the reactivity of the monomer and the desired characteristics, but the reaction time is 0.5 to 8 hours and the reaction temperature is 40 to 100 ° C. as a stable and economical production level. Particularly preferred.
Upon completion of the reaction, a condensate is obtained. Then, a bifunctional phenol compound and an acidic catalyst are further added to the reactor to perform a secondary reaction.
The reaction temperature and time of the secondary reaction can be appropriately selected depending on the characteristics of the resin to be produced and the reactivity of the monomer. ~ 150 ° C is particularly preferred.
When the secondary reaction is completed, a product containing the first alkali-soluble novolak resin, a monomer and the like is obtained.
[0021]
At the time of the primary reaction / secondary reaction, a reaction solvent can be added and used as necessary. Although the type of the solvent is not particularly limited, any solvent can be used as long as it dissolves the phenol resin. Examples thereof include ketones such as γ-butyrolactone, methyl ethyl ketone and methyl isobutyl ketone, alcohols such as butanol, and ether alcohols such as ethoxyethanol.
[0022]
After completion of the reaction, it is preferable to add water and wash with water in order to remove the acid and the base catalyst.
Although the amount and the number of times of washing water are not particularly limited, the number of times of washing is preferably about 1 to 5 times from the viewpoint of the amount of residual catalyst and the economy. The washing temperature is not particularly limited, but it is preferable to perform the washing at a temperature of 40 to 95 ° C. from the viewpoint of the efficiency of removing the catalyst species and the workability. During the washing, if the separation of the resin and the washing water is poor, it is effective to add a solvent that reduces the viscosity of the resin or to increase the washing temperature. This solvent is not particularly limited, but any solvent can be used as long as it dissolves the phenol resin and lowers the viscosity. Examples include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, alcohols such as methanol, ethanol and butanol, and ether alcohols such as ethoxy ethanol. Can be
[0023]
After completion of the water washing, dehydration and demonomerization are performed under normal pressure and reduced pressure to obtain a first alkali-soluble novolak resin. The conditions of dehydration and demonomerization are not limited. However, considering the stability (variation) and viscosity of the obtained phenol resin, it is particularly preferable to perform the depressurization at about 0.1 torr to about 200 torr. It is particularly preferable that the temperature for taking out from the glass is 150 to 250 ° C.
[0024]
(Ii) A method in which m-cresol and an aldehyde are subjected to a condensation reaction in the presence of an acid catalyst to obtain a condensate (primary reaction), and then a bifunctional phenol compound or a methylol derivative thereof is reacted in the presence of an acid catalyst. (Secondary reaction).
In this case, since the methylol group does not exist on the surface of the condensate obtained in the primary reaction, in the secondary reaction, a bifunctional phenol compound and an aldehyde are used, or a methylol derivative of the bifunctional phenol compound is used, The reaction is performed in the presence of a catalyst.
The molar ratio (A1) / (M) of the aldehyde (A1) and m-cresol (M) at the time of the primary reaction is (0.5 to 3.0) / 1. When the content is within this range, control during the two-hour reaction is facilitated, which is preferable.
[0025]
The same acid catalyst as that used in the secondary reaction (i) can be used as the acid catalyst.
The amount of the acid catalyst used is not particularly limited, but is preferably from 0.1% by mass to 20% by mass with respect to the solid content of the resin from the viewpoint of the reaction progress rate and control.
In this case, the acid catalyst can be used for the reaction in the secondary reaction as it is charged in the primary reaction, so that it is often unnecessary to add the acid catalyst in the secondary reaction.
The reaction conditions and operations for the primary reaction and the secondary reaction can be the same as those in the above (i).
[0026]
In the above (i) and (ii), the polystyrene-equivalent mass average molecular weight (Mw) of the condensate is preferably in the range of 500 to 15000, particularly 1000 to 6000, for good resist pattern formation and other properties. It is preferable in that it is excellent.
In addition, Mw can be measured by GPC (gel permeation chromatography).
[0027]
It is preferable that the first alkali-soluble novolak resin has Mw = 2000 to 20,000, particularly 3500 to 9000, and Mw / Mn (number average molecular weight) of 6.0 or less, particularly 5.0 or less. It is preferable in that it has excellent resist pattern formation and other properties.
[0028]
The mixing ratio of m-cresol (M) and the bifunctional phenol compound or its methylol (P-2) used in the synthesis is (M) / (P-2) = (0.3 to 0.7) / 1 (molar ratio), in particular, (0.4 to 0.6) / 1 (molar ratio) is preferable in that it is excellent in forming a high-contrast resist pattern.
This blending amount is particularly preferable in the case of using only a bifunctional phenol compound or its methylol derivative as the phenol compound in the secondary reaction.
[0029]
Further, at the time of the secondary reaction, a monofunctional phenol compound may be used together with the bifunctional phenol compound. Thereby, an effect of narrowing the band of the degree of dispersion can be obtained.
The monofunctional phenol compound refers to a compound having a substituent at two of two ortho positions and one para position of phenol, and having no substituent bonded to the other one.
In the secondary reaction (ii), when an aldehyde is not used and a methylol of a bifunctional phenol compound is used, it is preferable to use the methylol of the monofunctional phenol compound.
[0030]
As the monofunctional phenol compound, a phenol compound having a molecular weight of about 100 to 150 is preferable. For example, 2,4-xylenol, 2,6-xylenol, 2,3,4-trimethylphenol, 3,4,6-trimethylphenol , 2,3,6-trimethylphenol and the like, and one or more of these can be used.
Among them, 2,3,6-trimethylphenol is preferable because a resist pattern having a rectangular cross section can be easily obtained.
Preferred is the same in the case of a methylol compound.
[0031]
In this case, the mixing ratio of m-cresol (M), the bifunctional phenol compound or its methylol derivative (P-2) and the monofunctional phenol compound or its methylol derivative (P-1) at the time of synthesis is as follows:
(M) / [(P-1) + (P-2)] = (0.4 to 0.9) / 1 (molar ratio) and
It is preferable that (P-2) / (P-1) = (0.5 to 0.9) / 1 (molar ratio) from the viewpoint of obtaining a low degree of dispersion.
In particular, it is preferable that the former is (0.5 to 0.7) / 1 (molar ratio) and the latter is (0.6 to 0.8) / 1 (molar ratio), so that the resist pattern shape is excellent (resist pattern). (A cross-sectional shape takes a shape close to a rectangle).
This mixing ratio is particularly preferable when only a bifunctional phenol compound or its methylol and a monofunctional phenol compound or its methylol are used as the phenol compound used in the secondary reaction.
In addition, preferably, other than a bifunctional phenol compound or its methylol compound and a monofunctional phenol compound or its methylol compound during the secondary reaction, as long as the composition ratio of all the phenolic structural units in the component (A) described later is satisfied. Other phenolic compounds can also be used.
In this case, it is preferable that the amount of the first alkali-soluble novolak resin also satisfies the composition ratio of all the phenolic structural units in the component (A) described later.
[0032]
Also, as the first alkali-soluble novolak resin,
(A-1) a component synthesized using only m-cresol and a bifunctional phenol compound as the phenol compound used in the primary reaction and the secondary reaction,
Component (A-2) synthesized using only m-cresol, a bifunctional phenol compound and a monofunctional phenol compound as the phenol compound used in the primary reaction and the secondary reaction.
The use of a mixture of these is preferred because a resist composition having an excellent balance between sensitivity and resolution can be prepared.
At this time, the mixing ratio of the component (A-1) and the component (A-2) is (A-1) / (A-2) = (0.3 to 2.0) / 1 (mass ratio), In particular, it is preferable that the ratio is (0.4 to 1.5) / 1 (mass ratio) because the balance between sensitivity and resolution is particularly excellent.
[0033]
Further, in the component (A), an alkali-soluble novolak resin other than the first alkali-soluble novolak resin can be blended.
In this case, in the component (A), the content of the first alkali-soluble novolak resin is preferably 60% by mass or more, and more preferably 70% by mass or more, for obtaining the effects of the present invention.
What can be blended besides the first alkali-soluble novolak resin is not particularly limited, and one or more types can be arbitrarily selected from those usually used as a film-forming substance in a positive photoresist composition. Can be used.
[0034]
For example, phenols (phenol, m-cresol, p-cresol, xylenol, trimethylphenol, etc.) and aldehydes (formaldehyde, formaldehyde precursor, 2-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, etc.) or ketone Novolak resins other than the first alkali-soluble novolak resin obtained by condensing a compound (eg, methyl ethyl ketone, acetone, etc.) in the presence of an acidic catalyst.
[0035]
Further, all the phenolic constituent units in the component (A) containing the first alkali-soluble novolak resin are composed of only m-cresol constituent units, difunctional phenol compound constituent units, and monofunctional phenol compound constituent units. This is preferred because the balance of the properties of the resist is excellent.
The monofunctional phenol compound constituent unit may be contained in the first alkali-soluble novolak resin, or may be contained in other alkali-soluble novolak resins. Further, another alkali-soluble novolak resin may include a bifunctional phenol compound constituent unit.
That is, the “all phenol-based constituent units in the component (A)” refers to not only the first alkali-soluble novolak resin but also all phenol-based constituent units contained in other alkali-soluble novolak resins.
The content ratio thereof is m-cresol constituent unit / bifunctional phenol compound constituent unit / monofunctional phenol compound constituent unit = (35-40) / (35-50) / (10-25) (molar ratio). This is preferable because the upper part of the resist pattern is not rounded and a resist pattern having a rectangular cross section can be easily obtained.
It is more preferable that the phenolic structural unit in the first alkali-soluble novolak resin satisfies this composition.
[0036]
Further, the total phenol-based structural unit may be composed of an m-cresol structural unit, a bifunctional phenol compound structural unit, a monofunctional phenol compound structural unit, and another phenol-based structural unit.
In this case, their content ratio is m-cresol constituent unit / bifunctional phenol compound constituent unit / monofunctional phenol compound constituent unit / other phenolic constituent units = (35-40) / (35-50) / A ratio of (10 to 25) / (5 to 10) (molar ratio) is preferable from the viewpoint of excellent balance of resist characteristics.
Other structural units of the phenol compound are not particularly limited, and include, for example, m-ethylphenol, 3,5-dimethylphenol, 3,5-diethylphenol, dihydroxybenzene and the like.
Further, other phenol compound constituent units may be contained in the first alkali-soluble novolak resin as described above, or may be contained in another alkali-soluble novolak resin.
It is more preferable that the phenolic structural unit of the first alkali-soluble novolak resin satisfies this composition.
[0037]
<(B) component>
The component (B) is a non-benzophenone-based naphthoquinonediazidesulfonic acid ester.
The component (B) is not particularly limited, and a component known as a photosensitive agent for a positive photoresist composition for i-line can be used.
In particular, an esterified product of a naphthoquinonediazidesulfonic acid compound and at least one compound selected from the compounds represented by the general formula (I) is preferable because of its excellent high sensitivity and high resolution.
Among them, an esterified product having a linear pentanuclear phenol skeleton is preferable.
Examples of the phenol compound corresponding to the general formula (I) include tris (4-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2, 3,5-trimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3- Hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy- 2,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydrido) Xy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) ) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2,4-dihydroxyphenylmethane, bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane, Bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl- 4-hydroxy-2-methylphenyl) -2-hydroxy Enirumetan, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-trisphenol compounds such dihydroxyphenylmethane;
[0038]
Linear type 3 such as 2,4-bis (3,5-dimethyl-4-hydroxybenzyl) -5-hydroxyphenol and 2,6-bis (2,5-dimethyl-4-hydroxybenzyl) -4-methylphenol Core phenol compound; 1,1-bis [3- (2-hydroxy-5-methylbenzyl) -4-hydroxy-5-cyclohexylphenyl] isopropane, bis [2,5-dimethyl-3- (4-hydroxy -5-methylbenzyl) -4-hydroxyphenyl] methane, bis [2,5-dimethyl-3- (4-hydroxybenzyl) -4-hydroxyphenyl] methane, bis [3- (3,5-dimethyl-4) -Hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-dimethyl-4-hydroxybenzyl) -4-hydride Xy-5-ethylphenyl] methane, bis [3- (3,5-diethyl-4-hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-diethyl-4-) (Hydroxybenzyl) -4-hydroxy-5-ethylphenyl] methane, bis [2-hydroxy-3- (3,5-dimethyl-4-hydroxybenzyl) -5-methylphenyl] methane, bis [2-hydroxy-3] -(2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [4-hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [2,5 Linear nucleated phenol compounds such as -dimethyl-3- (2-hydroxy-5-methylbenzyl) -4-hydroxyphenyl] methane;
2,4-bis [2-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] -6-cyclohexylphenol, 2,4-bis [4-hydroxy-3- (4-hydroxybenzyl) -5 Linear type 5 such as -methylbenzyl] -6-cyclohexylphenol, 2,6-bis [2,5-dimethyl-3- (2-hydroxy-5-methylbenzyl) -4-hydroxybenzyl] -4-methylphenol Linear polyphenol compounds such as core phenol compounds;
Bis (2,3,4-trihydroxyphenyl) methane, bis (2,4-dihydroxyphenyl) methane, 2,3,4-trihydroxyphenyl-4′-hydroxyphenylmethane, 2- (2,3,4 -Trihydroxyphenyl) -2- (2 ', 3', 4'-trihydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- (2 ', 4'-dihydroxyphenyl) propane, -(4-hydroxyphenyl) -2- (4'-hydroxyphenyl) propane, 2- (3-fluoro-4-hydroxyphenyl) -2- (3'-fluoro-4'-hydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- (4′-hydroxyphenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (4′-hydroxyphenyl) Le) propane, 2- (2,3,4-hydroxyphenyl) -2- (4'-hydroxy-3 ', bisphenol type compounds such as 5'-dimethylphenyl) propane;
1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, 1- [1- (3-methyl-4-hydroxyphenyl) isopropyl]- Polynuclear branched compounds such as 4- [1,1-bis (3-methyl-4-hydroxyphenyl) ethyl] benzene;
And condensed phenol compounds such as 1,1-bis (4-hydroxyphenyl) cyclohexane.
These can be used alone or in combination of two or more.
[0039]
The method for converting all or a part of the phenolic hydroxyl group of the compound represented by the general formula (I) into naphthoquinonediazidesulfonic acid ester can be carried out by a conventional method.
For example, it can be obtained by condensing naphthoquinonediazidosulfonyl chloride with the compound represented by the general formula (I).
Specifically, for example, a compound represented by the general formula (I) and naphthoquinone-1,2-diazide-4 (or 5) -sulfonyl chloride are converted into dioxane, n-methylpyrrolidone, dimethylacetamide, tetrahydrofuran, etc. Is dissolved in a predetermined amount in an organic solvent, and one or more basic catalysts such as triethylamine, triethanolamine, pyridine, alkali carbonate, alkali hydrogen carbonate and the like are added and reacted, and the obtained product is washed with water and dried. Can be prepared.
[0040]
The amount of the component (B) is preferably in the range of 10 to 60% by mass, more preferably 20 to 50% by mass, based on the total amount of the components (A) and (C). By setting the blending amount of the component (B) to be equal to or more than the lower limit, an image faithful to the pattern can be obtained, and transferability can be improved.
On the other hand, by setting the blending amount of the component (B) to be equal to or less than the upper limit, deterioration in sensitivity and deterioration in uniformity of the formed resist film are suppressed, and deterioration in resolution is also suppressed.
[0041]
<(C) component>
The component (C) is an alkali-soluble phenolic hydroxyl group-containing compound having a molecular weight of 1,000 or less. By blending the component (C), the effect of improving sensitivity can be obtained.
The component (C) preferably has a mass average molecular weight of 1,000 or less, preferably 800 or less, substantially 200 or more, and more preferably 300 or more, from the viewpoint of the effect.
The component (C) is not particularly limited, and a known sensitizer (sensitivity improver) for a positive photoresist composition for i-line can be used.
In particular, a phenol compound represented by the general formula (I) is used.
Specifically, for example, the phenol compound used in the naphthoquinonediazide esterified product of the phenol compound exemplified in the component (B) can be preferably used.
[0042]
Further, a compound represented by the following general formula (III) and described in Japanese Patent No. 26299990 is also preferable.
[0043]
Embedded image

[0044]
(Where Z ¹ , Z ² , Z ³ , Z ⁴ , Z ⁵ , Z ⁶ , Z ⁷ , Z ⁸ And Z ⁹ Represents an alkyl group, a hydrogen atom, a halogen atom or an —OH group, at least one of which is an —OH group; ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ And R ²⁶ Represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group or an aryl group, respectively. )
[0045]
Among them, 2,6-bis (2,5-dimethyl-4-hydroxybenzyl) -4-methylphenol, 1,1-bis (4-hydroxyphenyl) benzene, 4- (3-hydroxyspiro [5,6, 7,8,10a, 8a-Hexahydroxanthene-9,1′-cyclohexane] -10a-yl) benzene-1,3-diol, 4- (2,3-dihydroxyspiro [5,6,7,8, 10a, 8a-Hexahydrosanthene-9,1'-cyclohexane] -10a-yl) benzene-1,2,3-triol and the like are preferred.
[0046]
The content of the component (C) is preferably from 5 to 50% by mass, more preferably from 10 to 35% by mass, based on the component (A). By setting the content within this range, the exposure latitude, the resolution, and the depth of focus characteristics are further improved, and the sensitivity is also excellent.
[0047]
The positive photoresist composition of the present invention is preferably used by dissolving the components (A), (B) and (C) in an organic solvent.
Examples of the solvent include solvents used in conventional positive photoresist compositions, for example, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone and 2-heptanone; ethylene glycol, propylene glycol, diethylene glycol, Ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, or polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; cyclic compounds such as dioxane Ethers; and ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate. Can be exemplified Le, esters such as ethyl ethoxypropionate. These may be used alone or as a mixture of two or more. In particular, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone and 2-heptanone; ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, etc. Esters are preferred.
The amount of the organic solvent used is determined so that the positive photoresist composition can be applied to the substrate, and is not particularly limited.
[0048]
<Other additives>
The composition of the present invention may further contain, if necessary, a compatible additive, an ultraviolet absorber for preventing halation such as 2,2 ', 4,4'-tetrahydroxybenzophenone, 4-dimethylamino. -2 ', 4'-dihydroxybenzophenone, 5-amino-3-methyl-1-phenyl-4- (4-hydroxyphenylazo) pyrazole, 4-dimethylamino-4'-hydroxyazobenzene, 4-diethylamino-4' Ethoxyazobenzene, 4-diethylaminoazobenzene, curcumin and the like, and a surfactant for preventing striation, for example, Florade FC-430, FC431 (trade name, manufactured by Sumitomo 3M Co., Ltd.), R-08, XR-104 ( (Trade name, manufactured by Dainippon Ink and Chemicals, Inc.) F-top EF122A, EF122B, EF122C EF126 (trade name, Tochem Products Ltd. Co.) can be added containing and fluorine-based surfactants such as in the range not interfering with the purposes of the present invention.
[0049]
[Method of forming resist pattern]
Hereinafter, an example of a preferred method for forming a resist pattern will be described.
First, the above-mentioned positive photoresist composition of the present invention is applied to a substrate with a spinner or the like to form a coating film. The substrate is preferably a silicon substrate.
Next, the substrate on which the coating film is formed is subjected to, for example, heat treatment (pre-baking) to remove the residual solvent, thereby forming a resist coating film.
Further, the resist film is selectively exposed using a mask (reticle) on which a mask pattern is drawn.
As a light source, it is preferable to use i-line (365 nm) in order to form a fine pattern.
Next, a heat treatment (post-exposure bake: PEB) is performed on the resist film after the selective exposure.
When the resist film after the PEB is subjected to a developing treatment using a developing solution, for example, an alkaline aqueous solution such as a 1 to 10% by mass aqueous solution of tetramethylammonium hydroxide, the exposed portions are dissolved and removed, and a resist pattern is formed. You.
Further, the resist pattern can be formed by washing away the developing solution remaining on the resist pattern surface with a rinse solution such as pure water.
[0050]
【Example】
Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.
[0051]
[Evaluation method of positive photoresist composition]
Evaluation methods for the following physical properties (1) to (5) for the positive photoresist compositions of the following examples or comparative examples are shown below.
[0052]
(1) Sensitivity
The sample was applied on a silicon wafer using a spinner, and dried (prebaked) on a hot plate at 90 ° C. for 90 seconds to obtain a resist film having a thickness of 1.05 μm. The film is exposed to the light through a mask (reticle) corresponding to a 0.35 μm resist pattern (L & S = 1: 1) using a reduction projection exposure apparatus NSR-2205i14E (manufactured by Nikon Corporation, NA = 0.57) from 0.1 second. After exposure at an interval of 0.01 seconds, PEB (post-exposure bake) treatment was performed at 110 ° C. for 60 seconds, developed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 23 ° C. for 60 seconds, and washed with water for 30 seconds. After drying, the exposure time (Eop) at which the line and space width of the 0.35 μm resist pattern was formed at a ratio of 1: 1 was expressed in milliseconds (ms) as sensitivity.
[0053]
(2-1) Depth of focus width characteristic [Isolated line pattern (Iso)]
Using a reduction projection exposure apparatus NSR-2205i14E (manufactured by Nikon Corporation, NA = 0.57), Eop [set dimensions of mask pattern (line width 0.35 μm, L & S 1: 1) are faithfully reproduced. The required exposure amount] was taken as a reference exposure amount, and at that exposure amount, the SEM photograph of Iso (line width: 0.35 μm) obtained by performing exposure and development while appropriately shifting the focal point was observed. From the SEM photograph, the maximum value (μm) of the focus shift obtained when a rectangular resist pattern of 0.35 μm was obtained within a range of ± 10% of the set dimension was defined as the depth of focus width characteristic.
[0054]
(2-2) Depth-of-focus width characteristic [line and space pattern (L & S)]
Using a reduction projection exposure apparatus NSR-2205i14E (manufactured by Nikon Corporation, NA = 0.57), Eop [set dimensions of mask pattern (line width 0.35 μm, L & S 1: 1) are faithfully reproduced. Observation of SEM photograph of L & S (line width 0.35 μm, L & S is 1: 1) obtained by performing exposure and development by appropriately shifting the focus up and down at the exposure amount. Was done. From the SEM photograph, the maximum value (μm) of the focus shift obtained when a rectangular resist pattern of 0.35 μm was obtained within a range of ± 10% of the set dimension was defined as the depth of focus width characteristic.
[0055]
(2-3) Depth of focus width characteristic [dot pattern]
Using a reduction projection exposure apparatus NSR-2205i14E (manufactured by Nikon Corporation, NA = 0.57), Eop [set dimensions of mask pattern (line width 0.35 μm, L & S 1: 1) are faithfully reproduced. The required exposure amount] was taken as a reference exposure amount, and the SEM photograph of a dot pattern (0.5 μm in diameter) obtained by performing exposure and development while appropriately shifting the focus up and down was observed. From the SEM photograph, the maximum value (μm) of the focus shift at which a resist pattern having a diameter of 0.5 μm was obtained within a range of ± 10% of the set dimension was defined as a depth of focus width characteristic.
[0056]
(2-4) Depth of focus width characteristics [Hole pattern]
Using a reduction projection exposure apparatus NSR-2205i14E (manufactured by Nikon Corporation, NA = 0.57), Eop [set dimensions of mask pattern (line width 0.35 μm, L & S 1: 1) are faithfully reproduced. The required exposure amount] was used as a reference exposure amount, and the SEM photograph of a hole pattern (0.5 μm in diameter) obtained by performing exposure and development while appropriately shifting the focus up and down at the exposure amount was observed. From the SEM photograph, the maximum value (μm) of the focus shift at which a resist pattern having a diameter of 0.5 μm was obtained within a range of ± 10% of the set dimension was defined as a depth of focus width characteristic.
[0057]
(2-5) Depth of focus width characteristics [trench turn (slit pattern)]
Using a reduction projection exposure apparatus NSR-2205i14E (manufactured by Nikon Corporation, NA = 0.57), Eop [set dimensions of mask pattern (line width 0.35 μm, L & S 1: 1) are faithfully reproduced. The required exposure amount] was taken as the reference exposure amount, and the SEM photograph of the trench pattern (width 0.4 μm) obtained by performing exposure and development while appropriately shifting the focus up and down was observed. From the SEM photograph, the maximum value (μm) of the focus shift, in which a resist pattern having a width of 0.4 μm was obtained within a range of ± 10% of the set dimension, was defined as the depth of focus width characteristic.
[0058]
[Synthesis Example 1]
A reaction vessel equipped with a condenser and a stirrer was charged with 36.0 g (0.33 mol) of m-cresol, 37.8 g (0.47 mol) of 37% by mass formalin, and 1.78 g of triethylamine, and gradually heated. And refluxed at 80 ° C. for 2 hours.
After cooling to room temperature, oxalic acid was added to neutralize, 72.0 g (0.67 mol) of p-cresol and 2 g of oxalic acid were added, and the reaction was carried out at a reaction temperature of 100 ° C. for 8 hours.
[0059]
After the completion of the reaction, the mixture was cooled to 70 ° C, 500 g of acetone and 600 g of pure water were added, and the mixture was stirred at about 70 ° C and allowed to stand.
After removing the separated water, a water washing operation was performed again using 500 g of acetone and 600 g of pure water.
Thereafter, dehydration was performed under normal pressure to an internal temperature of 140 ° C., and further dehydration was performed under reduced pressure of 60 torr to 195 ° C. and demonomerization was performed to obtain a novolak resin 1 (A1) having Mw = 3750 and Mw / Mn = 4.4. .
[0060]
[Synthesis Example 2]
A reaction vessel equipped with a condenser and a stirrer was charged with 43.2 g (0.4 mol) of m-cresol, 45.4 g (0.56 mol) of 37% by mass formalin, and 2.14 g of triethylamine, and gradually heated. And refluxed at 80 ° C. for 2 hours.
After cooling to room temperature, oxalic acid was added for neutralization, and p-cresol 27.0 (0.25 mol) g, 2,3,6-trimethylphenol 47.6 g (0.35 mol), oxalic acid 2 g Was added, and the reaction was carried out at a reaction temperature of 100 ° C. for 8 hours.
After the completion of the reaction, the mixture was cooled to 70 ° C, 500 g of acetone and 600 g of pure water were added, and the mixture was stirred at about 70 ° C and allowed to stand.
After removing the separated water, a water washing operation was performed again using 500 g of acetone and 600 g of pure water.
Thereafter, dehydration was performed under normal pressure to an internal temperature of 140 ° C., and further dehydration was performed under reduced pressure of 60 torr to 195 ° C., and demonomerization was performed to obtain novolak resin 2 (A2) having Mw = 4050 and Mw / Mn = 4.6. .
[0061]
[Synthesis Example 3] (Example in which the sixth invention is applied in Synthesis Example 1 and synthesized)
In a reaction vessel equipped with a cooler and a stirrer, 36.0 g (0.33 mol) of m-cresol, 18.7 g (0.23 mol) of 37% by mass formalin, and 2.0 g of oxalic acid were charged, and the temperature was gradually raised. Then, the mixture was refluxed at 100 ° C. for 8 hours.
After cooling to room temperature, 72.0 g (0.67 mol) of p-cresol and 38.0 g of 37% by mass formalin were added, and the reaction was carried out at a reaction temperature of 100 ° C. for 8 hours.
After the completion of the reaction, the mixture was cooled to 70 ° C, 500 g of acetone and 600 g of pure water were added, and the mixture was stirred at about 70 ° C and allowed to stand.
After removing the separated water, a water washing operation was performed again using 500 g of acetone and 600 g of pure water.
Thereafter, dehydration was performed under normal pressure to an internal temperature of 140 ° C., and further dehydration was performed under reduced pressure of 60 torr to 195 ° C. and demonomerization was performed to obtain a novolak resin 3 (A3) having Mw = 3800 and Mw / Mn = 4.8. .
[0062]
[Synthesis Example 4] (Example in which the seventh invention is applied in Synthesis Example 1 and synthesized)
A reaction vessel equipped with a condenser and a stirrer was charged with 36.0 g (0.33 mol) of m-cresol, 18.7 g (0.23 mol) of 37% by mass formalin, and 2.0 g of oxalic acid, and then γ-butyrolactone. Was added to adjust the concentration to 40% by mass, the temperature was gradually raised, and the mixture was refluxed at 100 ° C. for 8 hours.
After cooling to room temperature, a 40% by mass γ-butyrolactone solution containing 112.1 g (0.67 mol) of 2,6-dimethylol-p-cresol was added, and the reaction was carried out at 100 ° C. for 2 hours. went.
After the completion of the reaction, the mixture was cooled to 70 ° C, 500 g of acetone and 600 g of pure water were added, and the mixture was stirred at about 70 ° C and allowed to stand.
After removing the separated water, a water washing operation was performed again using 500 g of acetone and 600 g of pure water.
Thereafter, dehydration was performed under normal pressure to an internal temperature of 140 ° C., and further dehydration was performed under reduced pressure of 60 torr to 195 ° C. and demonomerization was performed to obtain a novolak resin 4 (A4) having Mw = 4200 and Mw / Mn = 5.0. .
[0063]
[Comparative Synthesis Example 1]
Synthesis Example 1 Synthesis Example 1 was the same as Synthesis Example 1 except that a resol reaction (primary reaction) was performed using p-cresol instead of m-cresol, and a novolak resin was synthesized using m-cresol instead of p-cresol. Novolak resin (Mw = 4200, Mw / Mn = 3.8) was synthesized in the same manner as described above.
[0064]
[Comparative Synthesis Example 2]
Synthetic Example 2 except that a resol reaction (primary reaction) was performed using p-cresol instead of m-cresol, and a novolak resin was synthesized using m-cresol instead of p-cresol in Synthesis Example 2. Novolak resin (Mw = 4500, Mw / Mn = 4.8) was synthesized in the same manner as described above.
[0065]
[Comparative Synthesis Example 3]
M-Cresol and p-cresol were simultaneously charged in the same amount as in Synthesis Example 1, and a novolak resin was synthesized by an ordinary method using an acid catalyst, and a novolak resin (Mw = 3800, Mw / Mn = 5.7). ) Was synthesized.
[0066]
[Comparative Synthesis Example 4]
M-Cresol, p-cresol, and 2,3,6-trimethylphenol were simultaneously charged in the same amount as in Synthesis Example 2, and a novolak resin synthesis reaction was carried out by an ordinary method using an acid catalyst, and a novolak resin (Mw = 4000, Mw / Mn = 6.7).
[0067]
[Example 1]
The following (A) to (F) are dissolved in 2-heptanone, the viscosity is adjusted to 6 cp at room temperature (23 ° C.), and the solution is filtered using a membrane filter having a pore size of 0.2 μm to obtain a positive photoresist composition. Was prepared.
[0068]
Component (A): 100 parts by mass
[A1 / A2 = 1/2 (mass ratio)]
Component (B): 52 parts by mass
[B1 / B2 = 5/1 (mass ratio)]
Component (C): 30 parts by mass
[C1 / C2 = 1/1 (mass ratio)]
Component (D): 2.73 parts by mass
[D1]
Component (E): 0.92 parts by mass
[E1]
Component (F): 0.08 parts by mass
[XR-104]
[0069]
In addition, each said symbol shows the following compounds.
B1: 1 mol of 2,6-bis [2,5-dimethyl-3- (2-hydroxy-5-methylbenzyl) -4-hydroxybenzyl] -4-methylphenol and naphthoquinone-1,2-diazide-5 -Esterification reaction product with 2 mol of sulfonyl chloride (hereinafter referred to as 5-NQD)
B2: Esterification reaction between 1 mol of 2,6-bis [2,5-dimethyl-3- (2-hydroxy-5-methylbenzyl) -4-hydroxybenzyl] -4-methylphenol and 3 mol of 5-NQD Product
C1: 2,6-bis [2,5-dimethyl-4-hydroxybenzyl] -4-methylphenol
C2: 1,1-bis (4-hydroxyphenyl) cyclohexane
D1: 1,4-bis [1- (2-methyl-4-hydroxy-5-cyclohexylphenyl) isopropyl] benzene
E1: p-toluenesulfonic acid chloride
[0070]
[Examples 2 to 3], [Comparative Examples 1 to 3]
A positive photoresist composition was prepared in the same manner as in Example 1 except that the component (A) in Example 1 was changed as shown in Table 1 below.
[0071]
[Table 1]

[0072]
[Example 4]
The following (A) to (E) were dissolved in 2-heptanone, the viscosity was adjusted to 5.5 cp at room temperature (23 ° C.), and the solution was filtered through a membrane filter having a pore size of 0.2 μm to obtain a positive photoresist composition. Was prepared.
Component (A): 100 parts by mass
[A1 / A2 / A5 = 4/5/6 (mass ratio)]
Component (B): 52 parts by mass
[B1 / B2 = 5/1 (mass ratio)]
Component (C): 30 parts by mass
[C3]
Component (D): 1.37 parts by mass
[D1]
Component (F): 0.08 parts by mass
[R-08]
[0073]
In addition, the said symbol shows the following compounds.
A5: A mixed phenol of formaldehyde / salicylaldehyde = 10/1 (molar ratio) is mixed with a mixed phenol of m-cresol / p-cresol / 2,3,5-trimethylphenol = 40/35/25 (molar ratio). Novolak resin (Mw = 3500) synthesized by a conventional method using a hydrochloric acid catalyst
C3: 4- (3-hydroxyspiro [5,6,7,8,10a, 8a-hexahydroxanthene-9,1′-cyclohexane] -10a-yl) benzene-1,3-diol)
[0074]
[Comparative Example 4]
Same as Example 1 except that the component (B) in Example 1 was replaced with an esterified product of 1 mol of 2,3,4-trihydroxybenzophenone and 2 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride. Thus, a positive photoresist composition was prepared.
[0075]
[Comparative Example 5]
A positive photoresist composition was prepared in the same manner as in Example 1 except that the component (C) of Example 1 was not blended.
[0076]
Table 2 shows the evaluation results of the positive photoresist compositions of Examples and Comparative Examples.
[0077]
[Table 2]

[0078]
As is evident from the results shown in Table 2, the positive photoresist compositions of the examples exhibited practical values of sensitivity, and the depth of focus characteristics were well balanced in each pattern. The resolution was also good. In addition, the occurrence of scum was small and the resist pattern shape was good.
[0079]
【The invention's effect】
In the production of an VLSI requiring a high resolution of half a micron or less, particularly 0.35 μm or less, a positive photoresist composition excellent in sensitivity, resolution, and depth of focus (DOF) can be provided.

Claims (12)

(A) an alkali-soluble novolak resin,
In a positive photoresist composition containing (B) a non-benzophenone-based naphthoquinonediazidesulfonic acid ester and (C) an alkali-soluble phenolic hydroxyl group-containing compound having a molecular weight of 1,000 or less,
The positive component, wherein the component (A) contains a first alkali-soluble novolak resin that can be synthesized by reacting a condensate of m-cresol and an aldehyde with a bifunctional phenol compound or a methylol derivative thereof. -Type photoresist composition. In the first alkali-soluble novolak resin, the mixing ratio of m-cresol (M) and a bifunctional phenol compound or its methylol compound (P-2) is (M) / (P-2) = (0. 3. The positive photoresist composition according to claim 1, wherein the molar ratio is 3 to 0.7) / 1. The said 1st alkali-soluble novolak resin is a thing which can be synthesize | combined by making the said condensate react a bifunctional phenol compound and a monofunctional phenol compound, or these methylol bodies. A positive photoresist composition. In the first alkali-soluble novolak resin, the mixing ratio of m-cresol (M), a bifunctional phenol compound or its methylol (P-2) and a monofunctional phenol compound or its methylol (P-1) is ,
(M) / [(P-1) + (P-2)] = (0.4 to 0.9) / 1 (molar ratio) and (P-2) / (P-1) = (0. The positive photoresist composition according to claim 3, wherein the molar ratio is 5 to 0.9) / 1. The first alkali-soluble novolak resin,
To a condensate which can be synthesized by a condensation reaction between m-cresol and an aldehyde in the presence of a basic catalyst,
The compound according to any one of claims 1 to 4, wherein the compound can be synthesized by reacting a bifunctional phenol compound or a bifunctional phenol compound and a monofunctional phenol compound in the presence of an acid catalyst. The positive photoresist composition according to the above. The first alkali-soluble novolak resin,
To a condensate that can be synthesized by a condensation reaction between m-cresol and an aldehyde in the presence of an acid catalyst,
The compound according to any one of claims 1 to 4, wherein the compound can be synthesized by reacting a bifunctional phenol compound or a bifunctional phenol compound and a monofunctional phenol compound in the presence of an aldehyde and an acid catalyst. The positive photoresist composition according to claim 1 or 2. The first alkali-soluble novolak resin,
To a condensate that can be synthesized by a condensation reaction between m-cresol and an aldehyde in the presence of an acid catalyst,
The compound can be synthesized by reacting a methylol of a bifunctional phenol compound, or a methylol of a bifunctional phenol compound and a methylol of a monofunctional phenol compound in the presence of an acid catalyst. The positive photoresist composition according to any one of claims 1 to 4. The positive photoresist composition according to any one of claims 1 to 7,
A positive photoresist composition, wherein all the phenolic constituent units of the component (A) are composed of m-cresol constituent units, bifunctional phenol compound constituent units, and monofunctional phenol compound constituent units. M-cresol constituent unit / bifunctional phenol compound constituent unit / monofunctional phenol compound constituent unit = (35-40) / (35-50) / (10-25) (molar ratio) The positive photoresist composition according to claim 8, wherein The positive photoresist composition according to any one of claims 1 to 7,
All the phenolic structural units of the component (A) are characterized by comprising m-cresol structural units, bifunctional phenolic compound structural units, monofunctional phenolic compound structural units, and other phenolic structural units. Positive photoresist composition. In all the phenolic structural units, m-cresol structural unit / 2 bifunctional phenolic compound structural unit / 1 monofunctional phenolic compound structural unit / other phenolic structural units = (35-40) / (35-50) / ( The positive photoresist composition according to claim 10, wherein the molar ratio is 10 to 25) / (5 to 10). The component (B) is represented by the following general formula (I)

[Wherein, R ^{1 to} R ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms. R ¹⁰ and R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; when R ⁹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, Q represents a hydrogen atom; An alkyl group having 1 to 6 carbon atoms or a residue represented by the following chemical formula (II)

(Wherein R ¹² and R ¹³ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms) the expressed; c a is an integer of 1 to 3), if Q is bonded to terminus of ^{R 9} is, Q is ^{R 9} and, together with the carbon atoms between Q and ^{R 9,} carbon chain 3 A, b represents an integer of 1 to 3; d represents an integer of 0 to 3; n represents an integer of 0 to 3]; and naphthoquinonediazidosulfonic acid The positive photoresist composition according to any one of claims 1 to 11, wherein the composition is an esterified compound with a compound.