JP3922673B2 - Positive photosensitive resin composition and pattern forming method - Google Patents

Description

【００１７】
【化２】

【００１８】
【化３】

【００１９】
前記(a-1)〜(a-15)、(b-1)〜(b-8)で表される構造単位において、Ａ、Ｂは各々独立に水素原子、水酸基、カルボキシル基、アルコキシカルボニル基、炭素数が１〜10個の置換もしくは非置換の、アルキル基、アルコキシ基又はアルケニル基を表し、ＡとＢとが結合して環を形成してもよい。Ｘ、Ｙは、各々独立に酸の作用により分解する基を表す。
前記式(b-1)〜(b-8)、(c-1)〜(c-4)においてＲは水素原子、メチル基等の炭素数１〜３個のアルキル基を表す。Ｚは水素原子、炭素数が１〜10の置換もしくは非置換のアルキル基、アルコキシカルボニル基もしくは酸の作用により分解する基を表す。）
【００２０】
上記において、アルコキシカルボニル基としては、メトキシカルボニル基、エトキシカルボニル基、ブトキシカルボニル基等が挙げられる。
炭素数が１〜10個のアルキル基としては、置換されていてもよい、直鎖、分岐あるいは環状アルキル基が挙げられ、具体的には、メチル基、エチル基、プロピル基、イソプロピル基、ｎ−ブチル基、ｔ−ブチル基、シクロペンチル基、シクロヘキシル基、ヒドロキシメチル基、ヒドロキシエチル基等が挙げられる。
炭素数が１〜10個のアルコキシ基としては、メトキシ基、エトキシ基、ｎ−ブトキシ基、ｔ−ブトキシ基、プロポキシ基、イソプロポキシ基等が挙げられる。
炭素数が２〜10個のアルケニル基としては、アリル基、ビニル基、２−プロペニル基等が挙げられる。
ＡとＢとが結合して形成する環としては、ＡとＢが結合して
−Ｃ（＝Ｏ）−Ｏ−Ｃ（＝Ｏ）−、
−Ｃ（＝Ｏ）−ＮＨ−Ｃ（＝Ｏ）−、
−ＣＨ₂ −Ｃ（＝Ｏ）−Ｏ−Ｃ（＝Ｏ）−、
等を形成して環となったものが挙げられる。
【００２１】
酸の作用により分解する基としては、−（ＣＨ₂ ）_n −ＣＯＯＲａ基もしくは−（ＣＨ₂ ）_n −ＯＣＯＲｂ基が挙げられる。ここでＲａは、炭素数２〜２０個の炭化水素基を表し、その炭化水素基としては、ｔ−ブチル基、ノルボルニル基、シクロデカニル基等が挙げられる。Ｒｂとしては、テトラヒドロフラニル基、テトラヒドロピラニル基、エトキシエチル基、イソプロピルエチル基等のアルコキシエチル基、ラクトン基、又はシクロヘキシロキシエチル基を表す。ｎは０又は１を表す。
【００２２】
上記各基における更なる置換基としては、ハロゲン原子、シアノ基、ニトロ基等が挙げられる。
本発明においては、重合体（Ａ）に含有する環状脂肪族炭化水素骨格としては、有橋構造を有するものが好ましい。これにより、画像性能（レジストプロファイル、デフォーカスラチチュード等）が良好となる。このような有橋環状脂肪族炭化水素骨格を有する繰り返し単位としては、上記（ａ−２）から（ａ−１４）、（ｂ−１）〜（ｂ−３）、（ｂ−５）から（ｂ−８）で示される繰り返し単位が挙げられる。
【００２３】
上記式（ａ−１）〜（ａ−６）で示される構造単位からなる重合体（Ａ）は、
例えば環状オレフィン類をメタセシス触媒の存在下、有機溶媒中、あるいは非有機溶媒中で開環重合し、引き続き水素化することによって得られる。開環(共)重合は、例えばW.L.Truettら;J.Am.Chem.Soc.,82,2337(1960)、A.Pacreau;Macromol.Chem.,188,2585(1987)、特開昭51-31800号、特開平1-197460号、特開平2-42094号、EP−0789278号等に記載の合成方法により容易に重合できる。ここで用いられるメタセシス触媒としては、例えば高分子学会編:高分子の合成と反応(1),共 立出版p375-381(1992)、特開昭49-77999号に記載の化合物、具体的にはタングステン及び又はモリブデン系などの遷移金属のハロゲン化合物と有機アルミニウム化合物又はこれらと第三成分とからなる触媒系を挙げることができる。
【００２４】
上記タングステン及びモリブデン化合物の具体例としては、五塩化モリブデン、六塩化タングステン及びタングステンオキシテトラクロライドが挙げられ、有機アルミニウム化合物としては、トリエチルアルミニウム、トリイソブチルアルミニウム、トリヘキシルアルミニウム、ジエチルアルミニウムモノクロライド、ジ−ｎ−ブチルアルミニウムモノクロライド、エチルアルミニウムセスキクロライド、ジエチルアルミニウムモノブトオキサイド及びトリエチルアルミニウム−水（モル比１：０．５）が挙げられる。開環重合をおこなうにあたり、上記タングステン又はモリブデン化合物1モルに対する有機アルミニウム化合物の使用割 合は０．５モル以上が好ましい。
触媒の重合活性等を向上させるための第三成分としては、水、過酸化水素、酸素含有有機化合物、チッソ含有有機化合物、ハロゲン含有有機化合物、リン含有有機化合物、硫黄含有有機化合物、金属含有有機化合物が挙げられ、タングステン又はモリブデン化合物1モルに対して5モル以下の割合で併用される。単量体に対する触媒の使用割合は、それらの種類にもよるが通常、単量体１００モルに対して０．１〜２０モルの割合で使用される。
【００２５】
開環(共)重合における重合温度は−４０℃〜＋１５０℃が好ましく、不活性ガス雰囲気中で行うのが望ましい。使用される溶媒としては、ペンタン、ヘキサン、ヘプタン、オクタン等の脂肪族炭化水素；シクロペンタン、シクロヘキサン等の脂環族炭化水素；ベンゼン、トルエン、キシレン等の芳香族炭化水素；塩化メチレン、１，１−ジクロロエタン、１，２−ジクロロエチレン、１−クロロプロパン、１−クロロブタン、１−クロロペンタン、クロロベンゼン、ブロムベンゼン、ｏ−ジクロロベンゼン、ｍ−ジクロロベンゼン等のハロゲン化炭化水素；ジエチルエーテル、テトラヒドロフラン等のエーテル系化合物が挙げられる。
【００２６】
このような開環(共)重合により得られた重合体を水素化することにより、本発明に用いられる重合体（Ａ）が得られる。水素化反応において用いられる触媒は通常のオレフィン性化合物の水素添加反応に用いられている不均一触媒あるいは均一触媒を使用することができる。
不均一触媒としては、例えばパラジウム、白金、ニッケル、ルテニウム、ロジウムなどの貴金属触媒をカーボン、シリカ、アルミナ、チタニアなどの担体に担持させた固体触媒などが挙げられる。また均一触媒としては、例えばナフテン酸ニッケル/トリエチルアルミニウム、ニッケルアセチルアセトナート/トリエチルアルミニウム、オクテン酸コバルト/n-ブチルリチウム、チタノセンジクロリド/ジエチルアルミニウムモノクロリド、酢酸ロジウム、クロロトリス(トリフェニ ルホスフィン)ロジウムなどのロジウム触媒を挙げることができる。
これらの触媒のうち、不均一触媒は、反応活性が高く、反応後の触媒除去も容易であり、得られる重合体が着色しないので好都合である。
【００２７】
水素化反応は、常圧〜３００気圧、好ましくは３〜２００気圧の水素ガス雰囲気下において、０〜２００℃、好ましくは２０〜１８０℃で行うことができる。水素添加率は通常５０％以上、好ましくは７０％以上、さらに好ましくは８０％以上である。水素添加率が５０％未満の場合には、レジストの熱安定性や経時安定性を悪化させるので好ましくない。
【００２８】
上記式（ａ−７）〜（ａ−１５）で示される構造単位からなる重合体は、例えばフリーラジカル重合開始剤の有効量の存在下に、環状脂肪族炭化水素モノマーのラジカル(共)重合により合成できる。具体的には、J.Macromol.Sci.Chem.A-5(3)491(1971)、同A-5(8)1339(1971)、Polym.Lett.Vol.2,469(1964)、USP3143533 号、USP3261815号、USP3510461号、USP3793501号、USP3703501号、特開平2-146045号記載の方法により合成できる。
ラジカル(共)重合に用いられる好ましい開始剤は２，２’−アゾビス（２−メチルプロパンニトリル）や過酸化ベンゾイル，過酸化ジクミル等を挙げることができる。開始剤の濃度は、単量体の総重量に対して、通常０．０１〜１０重量％、好ましくは０．１〜５重量％である。重合温度は広範囲に変えられ、通常室温〜２５０℃の範囲、好ましくは４０〜２００℃の範囲、さらに好ましくは６０〜１６０℃の範囲で重合が行われる。
【００２９】
重合もしくは共重合は、有機溶剤中で行なうのが好ましい。所定の温度で単量体を溶解し、また生成重合体をも溶解する溶剤が好ましい。好ましい溶剤は共重合する単量体の種類によつても変わるが、例えばトルエン等の芳香族炭化水素類；酢酸エチル等の脂肪族；芳香族エステル類；テトラヒドロフラン等の脂肪族エーテル類を挙げることができる。
所定時間反応後、得られた重合体と未反応の単量体成分、溶剤等を分離する目的で減圧蒸留、精製を行うのが好ましい。
【００３０】
（ｂ−１）〜（ｂ−８）の構造単位を有する重合体、あるいは共重合成分（ｃ−１）〜（ｃ−４）を含むものは、フリーラジカル開始剤の有効量存在下でラジカル（共）重合により合成できる。
重合体（Ａ）中、環状脂肪族骨格を有する構造単位の含有量は、全構造単位の１０モル％以上が好ましく、より好ましくは２０モル％以上、更に好ましくは３０モル％以上である。
また、重合体（Ａ）中、酸分解性基を有する構造単位の含有量は、全構造単位の１０〜９０モル％であり、好ましくは１５〜８５モル％、更に好ましくは２０〜８０モル％である。
また、本発明に用いられる重合体中、（ｃ−１）〜（ｃ−４）で表される単位等の他の共重合成分の含有量は全単量体の繰り返し単位中３〜６０モル%が好ましく、より好ましくは５〜５５モル%、更に好ましくは１０〜５０モル%である。
【００３１】
重合体（Ａ）は、重量平均分子量が１５００〜１０００００の範囲にあることが好ましく、さらに好ましくは２０００〜７００００の範囲、特に好ましくは３０００〜５００００の範囲である。分子量が１５００未満では耐ドライエッチング耐性，耐熱性，基板との密着性が不十分であり、分子量が１０００００を越えるとレジスト感度が低下するため好ましくない。また、分子量分布（Ｍｗ／Ｍｎ）は好ましくは１．０〜６．０、より好ましくは１．０〜４．０であり小さいほど耐熱性、画像性能（レジストプロファイル、デフォーカスラチチュード等）が良好となる。また、未反応のモノマーが残存するとドライエッチング耐性が劣化したり、レジスト膜の透過率が低下するので好ましくない。未反応のモノマーは、重合体中２重量％以下、好ましくは１重量％以下である。
なお、重合体（Ａ）の重量平均分子量及び分子量分布（Ｍｗ／Ｍｎ）は、屈折率検知器をつけたゲルパーミエーションクロマトグラフィーで、ポリスチレン換算値として測定される。
【００３２】
本発明のポジ型感光性樹脂組成物において、重合体（Ａ）の含有量は、固形分換算で、５０〜９９．７重量％、好ましくは７０〜９９重量％である。
本発明のポジ型感光性樹脂組成物は、重合体（Ａ）以外に、必要により他のポリマーを含有することができる。他のポリマーの含有量は、重合体（Ａ）１００重量部あたり、好ましくは３０重量部以下、より好ましくは２０重量部以下、更に好ましくは１０重量部以下、特に好ましくは５重量部以下である。
【００３３】
本発明のポジ型感光性樹脂組成物が含有することができる上記他のポリマーとして、本発明の脂環式ポリマーと相溶するものであればよく、ポリｐ−ヒドロキシエチレン、水素化ポリｐ−ヒドロキシエチレン、ノボラック樹脂等を挙げることができる。
【００３４】
次に、本発明のポジ型感光性樹脂組成物に含有される(Ｂ)活性光線の照射により分解して酸を発生する化合物(以下、「（Ｂ）光酸発生剤」ともいう)について説明する。
本発明で使用される（Ｂ）光酸発生剤の例としては、光カチオン重合の光開始剤、光ラジカル重合の光開始剤、色素類の光消色剤、光変色剤、又は紫外線、遠紫外線、KrFエキシマレーザー光、ＡｒＦエキシマレーザー光、電子線、X線、分子線、イオンビームなどにより酸を発生するマイクロフォトレジストで公知の光酸発生剤及びそれらの混合物を適宜に選択して使用することができる。
なお、本発明においては、活性光線は、上記した如く放射線を包含する広い概念で用いられる。
【００３５】
（Ｂ）光酸発生剤は、本発明のポジ型感光性樹脂組成物に用いられる後述の有機溶剤に溶解するものであれば特に制限されないが、２２０ｎｍ以下の光で酸を発生する光酸発生剤であることが好ましい。また、単独でもしくは2種以上を組 み合わせ用いてもよく、適当な増感剤と組み合わせて用いてもよい。
【００３６】
使用可能な（Ｂ）光酸発生剤の例としては、例えばJ.Org.Chem.Vol.43,N0.15,3055(1978)に記載のトリフェニルスルホニウム塩誘導体及び特願平9-279071号に記載の他のオニウム塩(スルホニウム塩、ヨードニウム塩、ホスホニウム塩、ジ アゾニウム塩、アンモニウム塩)も用いることができる。
オニウム塩の具体例としては、ジフェニルヨードニウムトリフレート、ジフェニルヨードニウムピレンスルホネート、ジフェニルヨードニウムドデシルベンゼンスルホネート、トリフェニルスルホニウムトリフレート、トリフェニルスルホニウムヘキサフルオロアンチモネート、ジフェニルヨードニウムヘキサフルオロアンチモネート、トリフェニルスルホニウムナフタレンスルホネート、トリフェニルスルホニユムカンファースルホニウム、（４−メトキシフェニル）フェニルヨードニウムトリフルオロメタンスルホネート、ビス（ｔ−ブチルフェニル）ヨードニウムトリフルオロメタンスルホネート等を挙げることができる。
【００３７】
また、特開平3-103854号、特開平3-103856号、特開平4-1210960号で示される ジアゾジスルホン類やジアゾケトスルホン類、特開昭64-18143号、特開平2-245756号に記載のイミノスルホネート類、特開平2-71270号に記載のジスルホン類も 好適に用いることができる。更に、USP3849137号、特開昭63-26653号、特開昭62-69263号、特開昭63-146038号、特開昭63-163452号、特開昭62-153853号、特開昭63-146029号等に記載の光により酸を発生する基をポリマーの主鎖もしくは側鎖に導入した化合物も用いることができ、特開平7-25846号、特開平7-28237号、特開平7-92675号、特開平8-27120号記載の２−オキソシクロヘキシル基を有する脂肪族アルキルスルホニウム塩類、及びＮ−ヒドロキシスクシンイミドスルホネート類、さらにはJ.Photopolym.Sci.,Tech.,Vol.7,No.3,423(1994)に記載のスルホニウム塩なども好適に用いることができ、単独でもしくは2種以上の組み合せで用いられる。
これらの光酸発生剤のうち、特にオニウム塩がレジストの感度、解像力の点で良好であり、好ましく用いられる。
【００３８】
これらの（Ｂ）活性光線の照射により分解して酸を発生する化合物の含有量は、感光性樹脂組成物の全重量(固形分)を基準として、通常０．００１〜４０重量％、好ましくは０．０１〜２０重量％、更に好ましくは０．１〜１５重量％、特に好ましくは０．５〜１０重量％である。（Ｂ）光酸発生剤の量が０．００１重量％より少ないと感度が低くなり、４０重量％より多いとレジストの光吸収が高くなりすぎプロファイルの劣化やプロセスマージン、特にベークマージンが狭くなり好ましくない。
【００３９】
次に本発明のポジ型感光性樹脂組成物に含有される（Ｃ）含窒素塩基性化合物について説明する。（Ｃ）含窒素塩基性化合物としては、有機アミン、塩基性のアンモニウム塩、塩基性のスルホニウム塩などが用いられ、昇華やレジスト性能を劣化させないものであればよい。これらの含窒素塩基性化合物の中でも、有機アミンが画像性能が優れる点で好ましい。
例えば特開昭63-149640号、特開平5-249662号、特開平5-127369号、特開平5-289322号、特開平5-249683号、特開平5-289340号、特開平5-232706号、特開平5-257282号、特開平6-242605号、特開平6-242606号、特開平6-266100号、特開平6-266110 号、特開平6-317902号、特開平7-120929号、特開平7-146558号、特開平7-319163号、特開平7-508840号、特開平7-333844号、特開平7-219217号、特開平7-92678号、 特開平7-28247号、特開平8-22120号、特開平8-110638号、特開平8-123030号、特開平9-274312号、特開平9-166871号、特開平9-292708号、特開平9-325496号、特表平7-508840号、USP5525453号、USP5629134号、USP5667938号等に記載の塩基性化合物を用いることができる。
【００４０】
含窒素塩基性化合物としては、好ましくは、１，５−ジアザビシクロ［４．３．０］−５−ノネン、１，８−ジアザビシクロ［５．４．０］−７−ウンデセン、１，４−ジアザビシクロ［２．２．２］オクタン、４−ジメチルアミノピリジン、１−ナフチルアミン、ピペリジン、ヘキサメチレンテトラミン、イミダゾール類、ヒドロキシピリジン類、ピリジン類、４，４’−ジアミノジフェニルエーテル、ピリジニウムｐ−トルエンスルホナート、２，４，６−トリメチルピリジニウムｐ−トルエンスルホナート、テトラメチルアンモニウムｐ−トルエンスルホナート、及びテトラブチルアンモニウムラクテート、トリエチルアミン、トリブチルアミン等が挙げられる。
これらの中でも、１，５−ジアザビシクロ［４．３．０］−５−ノネン、１，８−ジアザビシクロ［５．４．０］−７−ウンデセン、１，４−ジアザビシクロ［２．２．２］オクタン、４−ジメチルアミノピリジン、１−ナフチルアミン、ピペリジン、ヘキサメチレンテトラミン、イミダゾール類、ヒドロキシピリジン類、ピリジン類、４，４’−ジアミノジフェニルエーテル、トリエチルアミン、トリブチルアミン等の有機アミンが好ましい。
【００４１】
（Ｃ）含窒素塩基性化合物の含有量は、感光性樹脂組成物（固形分）１００重量部に対し、通常、０．００１〜１０重量部、好ましくは０．００１〜５重量部、より好ましくは０．００１〜０．５重量部である。０．００１重量部未満では（Ｃ）成分の添加効果が十分得られない。一方、１０重量部を越えると感度の低下や非露光部の現像性が著しく悪化する傾向がある。（Ｃ）塩基性化合物は、１種単独であるいは２種以上を組み合わせて用いることができる。
【００４２】
本発明においては、前記(B)光酸発生剤と(C)含窒素塩基性化合物の組成物中の混合重量比((B)/(C))は５〜３００の範囲であることが好ましく、より好ましくは１０〜２００の範囲である。この範囲にすることにより、レジスト感度、解像力がより良好となり、露光後の引き置きによるパターンの線幅依存性(PED依存性)が軽減できる。即ち、上記(B)と(C)の混合重量比にすることにより、レジスト感度、解像力、PED依存性が両立化する。
【００４３】
次に本発明のポジ型感光性樹脂組成物に含有される（Ｄ）フッ素系及び／又はシリコン系界面活性剤について説明する。
本発明の感光性樹脂組成物には、フッ素系界面活性剤、シリコン系界面活性剤及びフッ素原子とケイ素原子含有界面活性剤のいずれか、あるいはこれらを二種以上を含有することができる。
これらの（Ｄ）界面活性剤として、例えば特開昭62-36663号、特開昭61-226746号、特開昭61-226745号、特開昭62-170950号、特開昭63-34540号、特開平7-230165号、特開平8-62834号、特開平9-54432号、特開平9-5988号記載の界面活性剤を挙げることができ、下記市販の界面活性剤をそのまま用いることもできる。
使用できる市販の界面活性剤として、例えばエフトップEF301、EF303、(新秋田化成(株)製)、フロラードFC430、431(住友スリーエム(株)製)、メガファックF171、F173、F176、F189、R08（大日本インキ（株）製）、サーフロンS−382、SC101、102、103、104、105、106（旭硝子（株）製）等のフッ素系及び／又はシリコン系界面活性剤を挙げることができる。またポリシロキサンポリマーKP−341（信越化学工業（株）製）もシリコン系界面活性剤として用いることができる。
【００４４】
（Ｄ）界面活性剤の配合量は、本発明の組成物中の固形分１００重量部当たり、通常０．００１重量部〜２重量部、好ましくは０．００３重量部〜０．１０重量部である。
これらの界面活性剤は１種単独であるいは２種以上を組み合わせて用いることができる。
【００４５】
また、本発明においては、組成物中の(D)界面活性剤に対する(A)重合体の重量割合((A)/(D))が５００〜２００００の範囲であることが好ましく、より好ましくは１０００〜１５０００の範囲である。この割合とすることにより、現像性や線幅再現性が向上し、塗布膜厚の均一性が良好となる。
本発明のポジ型感光性樹脂組成物が、前記の現像欠陥に対しなぜ特異的に優れるのかはよくわかっていないが、（Ｃ）含窒素塩基性化合物と特定の（Ｄ）界面活性剤の組み合わせにより発現したものと思われる。例えば（Ｃ）含窒素塩基性化合物と本発明以外の界面活性剤の組み合わせ、例えばノニオン系の界面活性剤などとの組み合わせでは、プロファイル等の画像性能が不十分である。
【００４６】
本発明のポジ型感光性樹脂組成物は、必要に応じて、分子量が２０００以下であって、酸の作用により分解し得る基を有し、アルカリ溶解性が酸の作用により増大する低分子酸分解性化合物を含むことができる。
例えばProc.SPIE,2724, 355(1996)、特開平8-15865号、USP5310619号、USP−5372912号、J.Photopolym.Sci.,Tech.,Vol.10,No.3,511(1997))に記載されている酸分解性基を含有する、コール酸誘導体、デヒドロコール酸誘導体、デオキシコール酸誘導体、リトコール酸誘導体、ウルソコール酸誘導体、アビエチン酸誘導体等の脂環族化合物、酸分解性基を含有するナフタレン誘導体などの芳香族化合物を上記低分子酸分解性化合物として用いることができる。
さらに、特開平6-51519号記載の低分子の酸分解性溶解阻止化合物も２２０ｎ ｍの透過性を悪化させないレベルの添加範囲で用いることもできるし、１，２−ナフトキノンジアジト化合物も使用できる。
本発明の感光性樹脂組成物に上記低分子酸分解性溶解阻止化合物を使用する場合、その含有量は感光性樹脂組成物の１００重量部(固形分)を基準として、通常０．５〜５０重量部の範囲で用いられ、好ましくは０．５〜４０重量部、更に好ましくは０．５〜３０重量部、特に好ましくは０．５〜２０．０重量部の範囲で使用される。
これらの低分子酸分解性溶解阻止化合物を添加すると、前記現像欠陥がさらに改良されるばかりか耐ドライエッチング性が改良される。
【００４７】
本発明のポジ型感光性樹脂組成物には、必要に応じて、さらに現像液に対する溶解促進性化合物、ハレーション防止剤、可塑剤、界面活性剤、光増感剤、接着助剤、架橋剤、光塩基発生剤等を含有することができる。
【００４８】
本発明で使用できる現像液に対する溶解促進性化合物の例としては、例えば特開平3-206458号記載のフェノール性水酸基を２個以上含有する化合物、１−ナフトールなどのナフトール類又はカルボキシル基を１個以上有する化合物、カルボン酸無水物、スルホンアミド化合物やスルホニルイミド化合物などの分子量１０００以下の低分子化合物等を挙げることができる。
これらの溶解促進性化合物の配合量としては、組成物全重量(固形分)に対して、好ましくは３０重量％以下、より好ましくは２０重量％以下である。
【００４９】
好適なハレーション防止剤としては、照射する放射線を効率よく吸収する化合物が好ましく、フルオレン、９−フルオレノン、ベンゾフェノンのような置換ベンゼン類；アントラセン、アントラセン−９−メタノール、アントラセン−９−カルボキシエチル、フェナントレン、ペリレン、アジレンのような多環式芳香族化合物などが挙げられる。なかでも、多環式芳香族化合物が特に好ましい。これらのハレーション防止剤は基板からの反射光を低減し、レジスト膜内の多重反射の影響を少なくさせることで、定在波改良の効果を発現する。
【００５０】
本発明の感光性樹脂組成物の塗布性を改良したり、現像性を改良する目的で、ノニオン系界面活性剤を併用することができる。
併用できるノニオン系界面活性剤として、ポリオキシエチレンラウリルエーテル、ポリオキシエチレンステアリルエーテル、ポリオキシエチレンオクチルフェニルエーテル、ポリオキシエチレンノニルフェニルエーテル、ポリエチレングリコールジラウレート、ポリエチレングリコールジステアレート、ポリオキシエチレンソルビタンモノステアレート、ソルビタンモノラウレート等が挙げられる。
【００５１】
また露光による酸発生率を向上させるために、光増感剤を添加することができる。好適な光増感剤として、ベンゾフェノン、ｐ,ｐ'−テトラメチルジアミノベンゾフェノン、２−クロロチオキサントン、アントロン、９−エトキシアントラセン、ピレン、フェノチアジン、ベンジル、ベンゾフラビン、アセトフェノン、フェナントレン、ベンゾキノン、アントラキノン、１，２−ナフトキノン等を挙げることができるが、これらに限定されるものではない。これらの光増感剤は前記ハレーション防止剤としても使用可能である。
【００５２】
本発明の感光性樹脂組成物は、上記各成分を溶解する溶媒に溶解した後、通常例えば孔径０．０５μｍ〜０．２μｍ程度のフィルターで濾過することによって溶液として調製される。ここで使用される溶媒としては、例えばエチレングリコールモノエチルエーテルアセテート、シクロヘキサノン、２−ヘプタノン、プロピレングリコールモノメチルエーテル、プロピレングリコールモノメチルエーテルアセテート、プロピレングリコールモノメチルエーテルプロピオネート、プロピレングリコールモノエチルエーテルアセテート、３−メトキシプロピオン酸メチル、３−エトキシプロピオン酸エチル、β−メトキシイソ酪酸メチル、酪酸エチル、酪酸プロピル、メチルイソブチルケトン、酢酸エチル、酢酸イソアミル、乳酸エチル、トルエン、キシレン、酢酸シクロヘキシル、ジアセトンアルコール、Ｎ−メチルピロリドン、Ｎ，Ｎ−ジメチルホルムアミド、γ−ブチロラクトン、Ｎ，Ｎ−ジメチルアセトアミドなどが挙げられる。これらの溶媒は単独もしくは組み合わせて用いられる。これらの溶剤のうち、前記組成物に対する溶解性や基板への塗布性、保存安定性などの観点より、特に乳酸エチル、プロピレングリコールモノメチルエーテルアセテート、プロピレングリコールモノメチルエーテル、プロピレングリコールモノメチルエーテルプロピオネ ート、3-メトキシプロピオン酸メチル、3-エトキシプロピオン酸エチル、2-ヘプタノンから選択される少なくとも1種の溶剤を全溶剤中７０重量％以上含有することが好ましい。
また、溶媒に含まれる水分はレジスト性能に影響するため、少ない方が好ましい。
【００５３】
さらに本発明の感光性樹脂組成物は、メタル等の金属不純物やクロルイオンなどの不純物成分を１００ｐｐｂ以下に低減しておくことが好ましい。これらの不純物が多く存在すると、半導体デバイスを製造する上で動作不良、欠陥、収率低下を招いたりするので好ましくない。
【００５４】
本発明の感光性樹脂組成物を基板上にスピナー、コーター等の適当な塗布方法により塗布後、プリベーク（露光前加熱）し、所定のマスクを通して２２０ｎｍ以下の波長の露光光で露光し、ＰＥＢ（露光後ベーク）を行い現像することにより良好なレジストパターンを得ることができる。
ここで用いられる基板としては半導体装置その他の製造装置において通常用いられる基板であればよく、例えばシリコン基板、ガラス基板、非磁性セラミックス基板などが挙げられる。また、これらの基板上にさらに必要に応じて追加の層、例えばシリコン酸化物層、配線用金属層、層間絶縁膜、磁性膜、反射防止膜層などが存在してもよく、また各種の配線、回路などが作り込まれていてもよい。さらにまた、これらの基板はレジスト膜の密着性を高めるために、常法に従って疎水化処理されていてもよい。適当な疎水化処理剤としては、例えば１，１，１，３，３，３−ヘキサメチルジシラザン（ＨＭＤＳ）などが挙げられる。
【００５５】
基板上に塗布されるレジスト膜厚は、約０．１〜１０μｍの範囲が好ましく、ＡｒＦ露光の場合は、約０．１〜１．５μｍ厚が推奨される。
基板上に塗布されたレジスト膜は、約６０〜１６０℃の温度で約３０〜３００秒間プリベークするのが好ましい。プリベークの温度が低く、時間が短かければレジスト膜中の残留溶剤が相対的に多くなり、密着性が劣化するなどの弊害を生じるので好ましくない。また、逆にプリベークの温度が高く、時間が長ければ、感光性樹脂組成物のバインダー、光酸発生剤などの構成成分が分解するなどの弊害が生じるので好ましくない。
【００５６】
プリベーク後のレジスト膜を露光する装置としては市販の紫外線露光装置、Ｘ線露光装置、電子ビーム露光装置、ＫｒＦエキシマ露光装置、ＡｒＦエキシマ露光装置、Ｆ₂エキシマ露光装置等が用いられ、特に本発明ではＡｒＦエキシマレーザーを露光光源とする装置が好ましい。
露光後ベークは酸を触媒とする保護基の脱離を生じさせる目的や定在波を消失させる目的、酸発生剤などを膜中に拡散させる目的等で行われる。この露光後ベークは先のプリベークと同様にして行うことができる。例えば、ベーキング温度は約６０〜１６０℃、好ましくは約９０〜１５０℃である。
【００５７】
本発明の感光性樹脂組成物の現像液としては水酸化ナトリウム、水酸化カリウム、炭酸ナトリウム、ケイ酸ナトリウム、アンモニア水等の無機アルカリ類、エチルアミン、ｎ−プロピルアミン等の第一アミン類、ジエチルアミン、ジ−ｎ−ブチルアミン等の第２アミン類、トリエチルアミン、メチルジエチルアミン等の第３アミン類、ジメチルエタノールアミン、トリエタノールアミン等のアルコールアミン類、水酸化テトラメチルアンモニウム（ＴＭＡＨ）、水酸化テトラエチルアンモニウム（ＴＥＡＨ）、トリメチルヒドロキシメチルアンモニウムヒドロキシド、トリエチルヒドロキシメチルアンモニウムヒドロキシド、トリメチルヒドロキシエチルアンモニウムヒドロキシド等の第４級アンモニウム塩、ピロール、ピペリジン、１，８−ジアザビシクロ−［５．４．０］−７−ウンデセン、１，５−ジアザビシクロ−［４．３．０］−５−ノナン等の環状アミン類等のアルカリ水溶液を使用することができる。
【００５８】
更に、上記アルカリ性水溶液にアルコール類やケトン類などの親水性の有機溶剤やノニオン系や陰イオン性界面活性剤及び陽イオン性界面活性剤や消泡剤等を適当量添加しても使用することができる。これらの添加剤は、レジストの性能を向上させる目的以外にも基板との密着性を高めたり、現像液の使用量を低減させたり、現像時の気泡に起因する欠陥を低減させる目的等でアルカリ性水溶液に添加される。
【００５９】
【実施例】
以下、本発明を実施例により更に詳細に説明するが、本発明がこれにより限定されるものではない。
合成例１（重合体Ａの合成）
特開平９−２４４２４７号公報、第４例に記載のノルボルネン誘導体の開環重合体の水素化物(繰り返し構造単位を下記する)を、ＥＰ０７８９２７８号明細書記載の方法に従って合成した。（重量平均分子量２２０００）
【００６０】
【化４】

【００６１】
合成例２（重合体Ｂの合成）
特開平９−２４４２４７号公報、第１例に記載のノルボルネン誘導体の開環重合体の水素化物(繰り返し構造単位を下記する)をＥＰ０７８９２７８号明細書記載の方法に従って合成した。（重量平均分子量１７０００）
【００６２】
【化５】

【００６３】
合成例３（重合体Ｃの合成）
ノルボルネン、無水マレイン酸、アクリル酸ｔ−ブチル及びアクリル酸の共重合体(繰り返し構造単位を下記する)を特開平１０−１０７３９号公報、第７例に記載の方法に従って合成した。（重量平均分子量１７０００、各繰り返し単位のモル比５０／２５／２５）
【００６４】
【化６】

【００６５】
合成例４（重合体Ｄの合成）
メタクリル酸アダマンチルとアクリル酸ｔ−ブチルの共重合体(繰り返し構造 単位を下記する)を特開平７−２３４５１１号公報、第１例に記載の方法に従っ て合成した。（重量平均分子量５０００、各繰り返し単位のモル比５８／４２）
【００６６】
【化７】

【００６７】
合成例５（酸分解性低分子化合物ａの合成）
コール酸１２２．７ｇ（０．３モル）とチオニルクロライド１２０ｍｌの混合物を１時間還流した。過剰のチオニルクロリドを除去し、得られた固体をテトラヒドロフラン１５０ｍｌに溶かし、カリウム−ｔ−ブシトキシド４０ｇ（０．３５モル）を徐々に加え、反応混合物を６時間還流した後、冷却し、水中に注いだ。得られた固体を濾過して集め、水で洗い減圧下で乾燥した。この粗製物をｎ−ヘキサンで再結晶し７０％の収率でコール酸−ｔ−ブチル（下記式）を得た。
【００６８】
【化８】

【００６９】
実施例１〜６、比較例１〜５
（感光性樹脂組成物の調製）
感光性樹脂成分を調製するに当たって、表１に記載した成分、即ち、合成例１〜４で合成した重合体Ａ、Ｂ、Ｃ、Ｄ、光酸発生剤としてトリフェニルスルホニウムトリフレート（ＰＡＧ−１）、合成例５で合成した酸分解性低分子化合物( 化合物ａ)、含窒素塩基性化合物、界面活性剤、及び溶剤としてプロピレングリ コールモノメチルエーテルアセテートの各成分を用いた。表１で点線が付されているものは、その成分を用いなかったことを意味する。
各成分を混合後、０．１μｍのテフロンフィルターにより濾過して感光性樹脂組成物を調製した。
用いられた場合の各成分の量は、下記の通りである。
重合体Ａ，Ｂ，Ｃ，Ｄ １０ｇ
光酸発生剤 ０．０６ｇ
酸分解性低分子化合物 ０．２５ｇ
含窒素塩基性化合物 ０．０４ｇ
界面活性剤 ０．０５ｇ
溶剤 ５７．４ｇ
このように調製された感光性樹脂組成物につき、下記方法により現像欠陥数及びレジストの画像性能を評価した。現像欠陥数の評価結果を表２に、画像性能の評価結果を表３に示した。
【００７０】
（現像欠陥数の評価方法）
（１）現像欠陥数−Ｉ
感光性樹脂組成物をスピンコーターによりヘキサメチルジシラザン処理を施したシリコン基板上に均一に塗布し、１２０℃で９０秒間ホットプレート上で加熱、乾燥を行い、０．５０μｍのレジスト膜を形成した。このレジスト膜を、マスクを通してＡｒＦエキシマレーザー光で露光し、露光後直ぐに１１０℃で９０秒間ホットプレート上で加熱した。更に２．３８重量％濃度のテトラメチルアンモニウムヒドロキシド水溶液で２３℃で６０秒間現像し、３０秒間純水にてリンスした後、乾燥した。このようにして得られたコンタクトホールパターンの形成されたサンプルを、ＫＬＡ２１１２機(ＫＬＡテンコール（株）製)により現像欠陥数を測定した(Threshold12、Pixcel Size＝０．３９）。
（２）現像欠陥数−II
上記（１）現像欠陥数−Ｉにおいて、露光しない以外は、加熱、現像、リンス、乾燥したサンプルについて同様に行い現像欠陥数を測定した。
【００７１】
（画像評価法）
上記（１）現像欠陥数−Ｉと同様に、０．５０μｍのレジスト膜を形成し、この膜について、露光、加熱、現像、リンス、乾燥した。その後、膜厚を膜厚計により測定し、残膜率〔（処理後の膜厚／処理前の膜厚）×１００〕を算出した。
さらに、形成された０．２５μmラインパターンを走査型電子顕微鏡で観察し、プロファイルを調べた。矩形な形状をしているものを○で表し、そうでないものを×で表した。
【００７２】
【表１】

【００７３】
表１中の各記号は、下記の通りである。
ＰＡＧ−１：トリフェニルスルホニウムトリフレート
Ｎ−１：ヘキサメチレンテトラミン
Ｎ−２：１，５−ジアザビシクロ［４．３．０］−５−ノネン
Ｎ−３：１，８−ジアザビシクロ［５．４．０］−７−ウンデセン
Ｎ−４：１，４−ジアザビシクロ［２．２．２］オクタン
Ｗ−１：メガファックＦ１７６（大日本インキ（株）製）（フッ素系）
Ｗ−２：メガファックＲ０８（大日本インキ（株）製）（フッ素およびシリコーン系）
Ｗ−３：ポリシロキサンポリマーＫＰ−３４１（信越化学工業（株）製）（シリコーン系）
Ｗ−４：ポリオキシエチレンノニルフェニルエーテル
Ｓ−１：プロピレングリコールモノメチルエーテルアセテート
【００７４】
【表２】

【００７５】
【表３】

【００７６】
表２及び表３の結果から明らかなように、本発明の感光性樹脂組成物は、いづれも現像欠陥が極めて少なく、矩形なプロファイルが形成されていた。
一方、（Ｃ）含窒素塩基性化合物及び（Ｄ）界面活性剤を用いない比較例１及び比較例５、（Ｄ）界面活性剤を用いたものの、（Ｃ）含窒素塩基性化合物を用いない比較例２、（Ｃ）含窒素塩基性化合物を用いたものの、（Ｄ）界面活性剤を用いない比較例３は、いずれも現像欠陥数が多かった。比較例４は、界面活性剤として本発明で特定されたものでないものを用いた例であり、現像欠陥は比較的少なかったが、レジストプロファイルに劣っていた。
【００７７】
実施例７〜１４、比較例６、７
（感光性樹脂組成物の調製)
感光性樹脂成分を調製するに当たって、下記表−４に記載した成分、即ち、合成例２〜４で合成した重合体Ｂ〜Ｄ、光酸発生剤として上記(PAG-1)又はトリフェニルスルホニウムパーフルオロブタンスルホネート(PAG-2)、合成例５で合成した酸分解性低分子化合物、含窒素塩基性化合物、界面活性剤、溶剤を表−４に記載の種類、重量割合で配合した。表−４で点線が付されているものは、その成分を用いなかったことを意味する。
各成分を混合後、0.1μmのテフロンフィルターにより濾過して感光性樹脂組成物を調製した。表−５は感光性樹脂組成物の構成成分の比率を示す。
【００７８】
【表４】

【００７９】
PAG-1、N-2、 N-3、N-4、W-1、W-2、W-3、W-4、S-1は、上記表−１に記載の化合物と同じである。
PAG-2:トリフェニルスルホニウムパーフルオロブタンスルホネート
S-2:プロピレングリコールモノメチルエーテル
S-3:乳酸エチル
S-4:3-エトキシプロピオン酸エチル
S-5:プロピレングリコールモノプロピルエーテルプロピオネート
S-6:2-ヘプタノン
【００８０】
【表５】

【００８１】
このように調製された感光性樹脂組成物につき、下記方法により現像欠陥数及びレジストの画像性能を評価した。現像欠陥数の評価結果を表−６に画像性能の評価結果を表−７に示した。
(現像欠陥数の評価方法)は、上記実施例１〜６のところで示した方法と同様の方法でおこなった。
【００８２】
(画像評価法)
スピンコーターにてヘキサメチルジシラザン処理を施したシリコン基板上にブリューワーサイエンス社製反射防止膜DUV-42を600Å均一に塗布し、100℃で90秒間ホットプレート上で乾燥した後、190℃で240秒間加熱乾燥を行った。その後、各感光性樹脂組成物をスピンコーターで塗布し130℃で90秒乾燥を行い0.50μmのレジスト膜を形成させた。このレジスト膜に対し、マスクを通してArFエキシマレーザー光で露光し、露光後直ぐに130℃で90秒間ホットプレート上で加熱した。更にテトラメチルアンモニウムヒドロキシド水溶液で23℃で60秒間現像し、30秒間純水にてリンスした後、乾燥し、レジストラインパターンを得た。その後、膜厚を膜厚計により測定し、残膜率を前述の如く算出した。
【００８３】
さらに、形成された0.25μmラインパターンを走査型電子顕微鏡で観察し、プロファイルを調べた。矩形な形状をしているものを○で表し、テーパー形状のものを×で表した。なお矩形ではあるが、庇状の形状のものは△で表した。
感度は0.25μmのマスクパターンを再現する露光量を示す。
解像力は0.25μmのマスクパターンを再現する露光量における限界解像力を示す。
現像性は現像残渣の観察されなかったものを○、やや観察されたものを△で表した。
【００８４】
【表６】

【００８５】
【表７】

【００８６】
表−６、７の結果から明らかなように、特定の成分の特定の比率にした本発明の組成物は、現像欠陥が極めて少なく、いづれも矩形なプロファイルが形成されており、感度、解像力、現像性が優れていた。
【００８７】
【発明の効果】
本発明のポジ型感光性樹脂組成物は、現像欠陥が極めて少なく、しかも特にＡｒＦエキシマレーザー光を露光光源とする場合、感度、解像力、現像性が良好で、優れたパターンプロファイルを示す。このため半導体素子製造に必要な微細パターンの形成に有効に用いることが可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a positive photosensitive resin composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photofabrication processes. More particularly, the present invention relates to a positive photosensitive resin composition suitably used for fine processing of a semiconductor element using short-wavelength light energy rays such as far ultraviolet rays, X-rays, and electron beams, and particularly a semiconductor using an ArF excimer laser. It is a positive photosensitive resin composition suitably used for microfabrication of an element.
[0002]
[Prior art]
In recent years, semiconductor integrated circuits have been highly integrated, LSIs and VLSIs have been put into practical use, and the minimum pattern width of integrated circuits has reached the sub-half micron region, and further miniaturization has progressed.
For this reason, the demand for a photolithography technique for forming a fine pattern is becoming stricter. As one of means for miniaturizing a pattern, it is known to shorten the wavelength of exposure light used for forming a resist pattern.
For example, in the production of a DRAM having a degree of integration up to 64 Mbits, i-line (365 nm) of a high-pressure mercury lamp has been used as a light source until now. In the mass production process of 256Mbit DRAM, KrF excimer laser (248nm) has been put into practical use as an exposure light source instead of i-line, and light sources with shorter wavelengths have been studied for the purpose of manufacturing DRAM with 1Gbit or higher integration. ArF excimer laser (193 nm), F ₂ Use of excimer laser (157 nm), X-rays, and electron beams is considered effective (Takumi Ueno et al., “Short Wavelength Photoresist Materials-Microfabrication for ULSI”, Bunshin Publishing, 1988) .
[0003]
In particular, ArF excimer laser is positioned as a next-generation exposure technique, and development of a resist having high sensitivity, high resolution, and excellent dry etching resistance for ArF excimer laser exposure is desired.
As resist materials for conventional i-line and KrF excimer laser exposure, resists containing aromatic polymers are widely used in order to obtain high dry etching resistance. For example, novolak resin-based resists or polyvinylphenol-based chemicals are used. Amplified resists are known. However, since the aromatic ring introduced for the purpose of imparting dry etching resistance hardly transmits light in the wavelength range of ArF excimer laser light, it is difficult to expose to the bottom of the resist film. A pattern having a good cross-sectional shape could not be obtained.
[0004]
As one of the solutions to the problem of resist transparency, it is known to use an aliphatic polymer containing no aromatic ring, such as polymethyl methacrylate (J. Vac. Sci. Technol., B9, 3357 (1991)). However, such a polymer cannot be put into practical use because sufficient dry etching resistance cannot be expected. As described above, in developing a resist material for ArF excimer laser exposure, the greatest challenge is to achieve both improved transparency and high dry etching resistance.
Therefore, Proc. SPIE, 1672, 66 (1992) reported that a resist containing an alicyclic hydrocarbon group instead of an aromatic ring exhibits the same dry etching resistance as an aromatic group and has a small absorption at 193 nm. Recently, the use of the polymer has been energetically studied.
[0005]
Originally, attempts to apply a polymer containing an alicyclic hydrocarbon group to a resist have been made for a long time. For example, in Japanese Patent Laid-Open Nos. 60-195542, 1-217453, and 2-59751, a norbornene-based polymer is used. A polymer is disclosed, and JP-A-2-46045 discloses various alkali-soluble resins having a cyclic aliphatic hydrocarbon skeleton and a maleic anhydride unit.
Further, JP-A-5-80515 discloses a copolymer of norbornene and an acrylate ester protected with an acid-decomposable group. JP-A-4-39665, JP-A-5-265212, JP-A-5-80515, JP-A-7-234511 discloses a copolymer having an adamantane skeleton in the side chain, and JP-A-7-252324 and JP-A-9-221526 have 7 to 12 carbon atoms having a bridged cyclic hydrocarbon group. A compound in which the aliphatic cyclic hydrocarbon group is linked to the side chain of the polymer, for example, tricyclo [5.2.1.02.6] decandimethylene group, tricyclo [5.2.1.02.6] decandiyl group, norbornanediyl Group, norbornanedimethyl group and adamantanediyl group are disclosed, and JP-A 7-199467 discloses tricyclodecanyl group, dicyclopentenyl group, dicyclopentenyloxyethyl group, norbornyl group, and cyclohexyl group as side chains of the polymer. The compound linked to It is disclosed.
[0006]
Further, JP-A-9-325498 discloses polymers having cyclohexane and isobornyl skeletons in the main chain, and further JP-A-9-230595, JP-A-9-244247, JP-A-10-10739, WO97-33198, EP 794458 and EP 789278 disclose polymers in which various cyclic olefins such as dicycloolefin are introduced into the main chain, and JP-A-8-82925 and JP-A-9-230597 describe a menthyl group in a terpenoid skeleton. Alternatively, it is disclosed that a compound having a menthyl derivative group is preferable.
[0007]
Apart from the resist performance as described above, the generation of defects (voids) due to the lithography process has become one of the major causes of yield reduction, and has recently become a particularly important problem.
For example, it is said that development defects are generally caused by bubbles at the time of liquid buildup and microbubbles caused by dissolved gas in the developer (Hirano et al .; Proceedings of the 42nd JSAP Meeting 27p- ZW-9 (1996)), countermeasures against bubbles are becoming more important as the wafer diameter increases and the developer discharge rate increases. As countermeasures for these bubbles, improvements have been made on the device that allows the developer to be discharged softly (see Science Forum, ULSI Manufacturing Contamination Control Technology, 41 (1992)) and the addition of a degassing mechanism for dissolved gas. Although attempts have been made to reduce bubbles, the level is not satisfactory.
In addition, in order to reduce development defects, nonionic surfactants are added to the developer to improve the wettability of the developer and promote bubble detachment, and surfactants in novolak resists. Attempts have been made to improve the affinity by optimizing the type and the amount added (Awashima et al .; 42nd JSAP lecture presentation 27p-ZW-7 (1996)).
However, these methods are not sufficient to reduce the development defects of chemically amplified resists for ArF using non-aromatic polymers. Rather, the development defects may be adversely affected. Until now, there was no guideline for improvement on how to deal with the reduction. Moreover, if the affinity of the resist is improved in order to reduce development defects, the remaining film rate and profile tend to deteriorate, making it difficult to achieve compatibility.
[0008]
Furthermore, conventional positive chemical amplification resists for KrF using aromatic polymers include, for example, Prooc.SPIE 1672,46, (1992), Prooc.SPIE 2438,551, (1995), Prooc.SPIE, 2438 , 563 (1995), Prooc.SPIE 1925,14, (1993), J.Photopolym.Sci.Tech.Vol.8.No.4,535 (1995), J.Photopolym.Sci.Tech.Vol.5.No. 1,207 (1992), J. Photopolym. Sci. Tech. Vol. 8, No. 4, 561 (1995), Jpn. J. Appl. Phys. 33, 7023 (1994), etc. As the standing time until (PEB) becomes longer, the generated acid diffuses, or the acid on the resist surface is deactivated by basic impurities in the atmosphere, and the sensitivity and profile of the resist pattern after development There was a problem that the line width would change.
As means for solving these problems, a technique of adding an amine to a chemically amplified resist using an aromatic polymer is disclosed in JP-A-63-149640, JP-A-5-249662, JP-A-5-127369, Kaihei 5-289322, JP 5-249683, JP 5-289340, JP 5-232706, JP 5-257282, JP 6-224055, JP 6-242606, JP JP-A-6-266100, JP-A-66-266110, JP-A-6-317902, JP-A-7-120929, JP-A-7-65558, JP-A-7-319163, JP-A-7-508840, JP-A-7 -333844, JP-A-7-219217, JP-A-7-92678, JP-A-7-28247, JP-A-8-22120, JP-A-8110638, JP-A8-123030, JP-A-9- No. 274312, JP-A-9-66871, JP-A-9-292708, JP-A-9-325496, JP 7-508840, USP5525453, USP5629134, USP5667938, etc. .
[0009]
However, when these amines are added to a chemically amplified resist for ArF using a non-aromatic polymer having a cycloaliphatic hydrocarbon skeleton structure, the sensitivity change is certainly the same as in the case of using an aromatic polymer. Although it is effective for resist pattern profile change and line width change after development, the development defect is extremely inferior, and countermeasures have been desired.
[0010]
[Problems to be solved by the present invention]
An object of the present invention is to provide a positive photosensitive resin composition that has excellent residual film ratio and resist profile and does not cause problems of development defects when deep ultraviolet light, particularly ArF excimer laser light is used as an exposure light source. There is.
A further object of the present invention is that when deep ultraviolet rays, particularly ArF excimer laser light, is used as an exposure light source, the image performance such as residual film ratio, resist profile, resolution, sensitivity, developability is excellent, and the problem of development defects is solved. An object of the present invention is to provide a positive photosensitive resin composition that does not occur.
[0011]
[Means for Solving the Problems]
As a result of intensive studies on the constituent materials of the positive chemically amplified resist composition, the present inventors have found that a polymer containing an alicyclic hydrocarbon skeleton structural unit, a photoacid generator, a nitrogen-containing basic compound, and a fluorine-based compound. It has been found that the object can be achieved by combining a silicon-based surfactant and / or a silicon-based surfactant.
That is, this invention is invention of the following structure, The said objective is achieved.
(1) (A) a polymer having a cyclic aliphatic hydrocarbon skeleton, which is decomposed by the action of an acid and becomes alkali-soluble,
(B) a compound that generates an acid upon irradiation with actinic rays,
(C) a nitrogen-containing basic compound, and
(D) Fluorine-based and / or silicon-based surfactant
A positive-type photosensitive resin composition comprising:
[0012]
(2) (A) a polymer having a bridged cyclic aliphatic hydrocarbon skeleton, which is decomposed by the action of an acid and becomes alkali-soluble,
(B) a compound that generates an acid upon irradiation with actinic rays,
(C) a nitrogen-containing basic compound,
(D) a fluorine-based and / or silicon-based surfactant, and
(E) Solvent
The weight ratio of (B) to (C) ((B) / (C)) is in the range of 5 to 300, and the weight ratio of (A) to (D) ((A) / (D) ) Is in the range of 500 to 20000, a positive photosensitive resin composition.
[0013]
(3) The molecular weight is 2,000 or less, the group further comprises a low-molecular acid-decomposable compound having a group that can be decomposed by the action of an acid and whose alkali solubility is increased by the action of an acid. The positive photosensitive resin composition as described in 1) or (2).
(4) The positive photosensitive resin as described in (3) above, wherein the content of the low-molecular acid-decomposable compound is 0.5 to 20.0 parts by weight with respect to 100 parts by weight of the solid component. Composition.
(5) The positive photosensitive resin composition as described in any one of (1) to (4) above, wherein the compound (B) is an onium salt.
(6) The positive photosensitive resin composition as described in any one of (1) to (5) above, wherein the nitrogen-containing basic compound of (C) is an organic amine.
[0014]
(7) The solvent of (E) is ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether propionate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate and 2- The positive photosensitive resin composition as described in (2) above, which contains at least one selected from heptanone in an amount of 70% by weight or more based on the total solvent.
(8) The positive photosensitive resin composition as described in any one of (1) to (7) above, wherein the actinic ray is far ultraviolet light having a wavelength of 220 nm or less.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the compounds used in the present invention will be described in detail.
First, as the polymer (A) having a cycloaliphatic hydrocarbon skeleton structure in the present invention, which is decomposed by the action of an acid and becomes alkali-soluble, a conventionally known polymer can be used. Specific examples of the groups include, for example, groups having a cyclic aliphatic hydrocarbon skeleton unit in the main chain as represented by the following (a-1) to (a-15) and decomposing by the action of an acid (acid-decomposable A polymer having a cyclic aliphatic hydrocarbon skeleton in the side chain and a polymer having a repeating unit represented by the following (b-1) to (b-8) and an acid-decomposable group: Can be mentioned.
Further, structural units having a cyclic aliphatic hydrocarbon skeleton structure such as structural units represented by the following (a-1) to (a-15) and (b-1) to (b-8) Although essential for the polymer concerned, structural units represented by the following (c-1) to (c-4) may be included as a copolymerization component.
[0016]
[Chemical 1]

[0017]
[Chemical 2]

[0018]
[Chemical 3]

[0019]
In the structural units represented by the above (a-1) to (a-15) and (b-1) to (b-8), A and B are each independently a hydrogen atom, a hydroxyl group, a carboxyl group, or an alkoxycarbonyl group. Represents a substituted or unsubstituted alkyl group, alkoxy group or alkenyl group having 1 to 10 carbon atoms, and A and B may combine to form a ring. X and Y each independently represent a group that decomposes by the action of an acid.
In the formulas (b-1) to (b-8) and (c-1) to (c-4), R represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms such as a methyl group. Z represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkoxycarbonyl group or a group capable of decomposing by the action of an acid. )
[0020]
In the above, examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, and a butoxycarbonyl group.
Examples of the alkyl group having 1 to 10 carbon atoms include a linear, branched or cyclic alkyl group which may be substituted. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, n -Butyl group, t-butyl group, cyclopentyl group, cyclohexyl group, hydroxymethyl group, hydroxyethyl group and the like can be mentioned.
Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, an n-butoxy group, a t-butoxy group, a propoxy group, and an isopropoxy group.
Examples of the alkenyl group having 2 to 10 carbon atoms include allyl group, vinyl group, and 2-propenyl group.
The ring formed by combining A and B includes A and B
-C (= O) -OC (= O)-,
-C (= O) -NH-C (= O)-,
-CH ₂ -C (= O) -OC (= O)-,
Etc. to form a ring.
[0021]
Examples of the group that decomposes by the action of an acid include — (CH ₂ ) _n -COORa group or-(CH ₂ ) _n -OCORb group. Here, Ra represents a hydrocarbon group having 2 to 20 carbon atoms, and examples of the hydrocarbon group include a t-butyl group, a norbornyl group, and a cyclodecanyl group. Rb represents a tetrahydrofuranyl group, a tetrahydropyranyl group, an alkoxyethyl group such as an ethoxyethyl group or an isopropylethyl group, a lactone group, or a cyclohexyloxyethyl group. n represents 0 or 1.
[0022]
Examples of the further substituent in each of the above groups include a halogen atom, a cyano group, and a nitro group.
In the present invention, the cyclic aliphatic hydrocarbon skeleton contained in the polymer (A) preferably has a bridged structure. Thereby, the image performance (resist profile, defocus latitude, etc.) is improved. Examples of the repeating unit having such a bridged cyclic aliphatic hydrocarbon skeleton include the above (a-2) to (a-14), (b-1) to (b-3), (b-5) to ( and the repeating unit represented by b-8).
[0023]
The polymer (A) comprising the structural units represented by the above formulas (a-1) to (a-6)
For example, it can be obtained by ring-opening polymerization of cyclic olefins in the presence of a metathesis catalyst in an organic solvent or a non-organic solvent, followed by hydrogenation. Ring-opening (co) polymerization is described in, for example, WL Truett et al .; J. Am. Chem. Soc., 82, 2337 (1960), A. Pacreau; Macromol. Chem., 188, 2585 (1987), JP-A-51-31800. No. 1, JP-A-1-197460, JP-A-2-42094, EP-0789278 and the like. Examples of the metathesis catalyst used here include compounds described in, for example, the Society of Polymer Science: Synthesis and Reaction of Polymers (1), Kyoritsu Shuppan p375-381 (1992), JP-A-49-77999. Can include a catalyst system comprising a halogen compound of a transition metal such as tungsten and / or molybdenum and an organoaluminum compound or these and a third component.
[0024]
Specific examples of the tungsten and molybdenum compounds include molybdenum pentachloride, tungsten hexachloride and tungsten oxytetrachloride. Examples of the organoaluminum compounds include triethylaluminum, triisobutylaluminum, trihexylaluminum, diethylaluminum monochloride, -N-butylaluminum monochloride, ethylaluminum sesquichloride, diethylaluminum monobutoxide and triethylaluminum-water (molar ratio 1: 0.5). In carrying out the ring-opening polymerization, the use ratio of the organoaluminum compound to 1 mol of the tungsten or molybdenum compound is preferably 0.5 mol or more.
As the third component for improving the polymerization activity of the catalyst, water, hydrogen peroxide, oxygen-containing organic compound, nitrogen-containing organic compound, halogen-containing organic compound, phosphorus-containing organic compound, sulfur-containing organic compound, metal-containing organic Compounds, and are used together at a ratio of 5 mol or less with respect to 1 mol of tungsten or molybdenum compound. The catalyst is used in a proportion of 0.1 to 20 mol with respect to 100 mol of the monomer, although the proportion of the catalyst to the monomer depends on the type of the catalyst.
[0025]
The polymerization temperature in the ring-opening (co) polymerization is preferably −40 ° C. to + 150 ° C., and is desirably performed in an inert gas atmosphere. Solvents used include aliphatic hydrocarbons such as pentane, hexane, heptane and octane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; methylene chloride, 1, Halogenated hydrocarbons such as 1-dichloroethane, 1,2-dichloroethylene, 1-chloropropane, 1-chlorobutane, 1-chloropentane, chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene; diethyl ether, tetrahydrofuran, etc. Examples include ether compounds.
[0026]
The polymer (A) used in the present invention is obtained by hydrogenating the polymer obtained by such ring-opening (co) polymerization. The catalyst used in the hydrogenation reaction may be a heterogeneous catalyst or a homogeneous catalyst used in the usual hydrogenation reaction of olefinic compounds.
Examples of the heterogeneous catalyst include a solid catalyst in which a noble metal catalyst such as palladium, platinum, nickel, ruthenium, or rhodium is supported on a carrier such as carbon, silica, alumina, or titania. Examples of homogeneous catalysts include nickel naphthenate / triethylaluminum, nickel acetylacetonate / triethylaluminum, cobalt octenoate / n-butyllithium, titanocene dichloride / diethylaluminum monochloride, rhodium acetate, chlorotris (triphenylphosphine) rhodium, etc. The rhodium catalyst can be mentioned.
Among these catalysts, the heterogeneous catalyst is advantageous because it has high reaction activity, is easy to remove after the reaction, and the resulting polymer is not colored.
[0027]
The hydrogenation reaction can be performed at 0 to 200 ° C., preferably 20 to 180 ° C. in a hydrogen gas atmosphere of normal pressure to 300 atm, preferably 3 to 200 atm. The hydrogenation rate is usually 50% or more, preferably 70% or more, and more preferably 80% or more. When the hydrogenation rate is less than 50%, the thermal stability and temporal stability of the resist are deteriorated.
[0028]
The polymer composed of the structural units represented by the above formulas (a-7) to (a-15) is, for example, radical (co) polymerization of a cyclic aliphatic hydrocarbon monomer in the presence of an effective amount of a free radical polymerization initiator. Can be synthesized. Specifically, J. Macromol. Sci. Chem. A-5 (3) 491 (1971), A-5 (8) 1339 (1971), Polym. Lett. Vol. 2,469 (1964), USP 3143533, It can be synthesized by the methods described in USP3261815, USP3510461, USP3793501, USP3703501, and JP-A-2-46045.
Preferable initiators used for radical (co) polymerization include 2,2′-azobis (2-methylpropanenitrile), benzoyl peroxide, dicumyl peroxide and the like. The concentration of the initiator is usually 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the total weight of the monomers. The polymerization temperature can be varied over a wide range, and the polymerization is usually carried out in the range of room temperature to 250 ° C, preferably in the range of 40 to 200 ° C, more preferably in the range of 60 to 160 ° C.
[0029]
The polymerization or copolymerization is preferably performed in an organic solvent. A solvent that dissolves the monomer at a predetermined temperature and also dissolves the produced polymer is preferable. The preferred solvent varies depending on the type of monomer to be copolymerized, and examples thereof include aromatic hydrocarbons such as toluene; aliphatics such as ethyl acetate; aromatic esters; and aliphatic ethers such as tetrahydrofuran. Can do.
After the reaction for a predetermined time, it is preferable to perform distillation under reduced pressure and purification for the purpose of separating the obtained polymer from unreacted monomer components, solvents and the like.
[0030]
Polymers having the structural units (b-1) to (b-8) or those containing the copolymer components (c-1) to (c-4) are free radicals in the presence of an effective amount of a free radical initiator. It can be synthesized by (co) polymerization.
In the polymer (A), the content of the structural unit having a cycloaliphatic skeleton is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more of the total structural units.
In the polymer (A), the content of the structural unit having an acid-decomposable group is 10 to 90 mol%, preferably 15 to 85 mol%, more preferably 20 to 80 mol%, based on all structural units. It is.
Moreover, in the polymer used for this invention, content of other copolymerization components, such as a unit represented by (c-1)-(c-4), is 3-60 mol in the repeating unit of all the monomers. % Is preferable, more preferably 5 to 55 mol%, still more preferably 10 to 50 mol%.
[0031]
The polymer (A) preferably has a weight average molecular weight in the range of 1500 to 100,000, more preferably in the range of 2000 to 70000, and particularly preferably in the range of 3000 to 50000. If the molecular weight is less than 1500, dry etching resistance, heat resistance, and adhesion to the substrate are insufficient, and if the molecular weight exceeds 100,000, the resist sensitivity is lowered, which is not preferable. The molecular weight distribution (Mw / Mn) is preferably 1.0 to 6.0, more preferably 1.0 to 4.0. The smaller the molecular weight distribution (Mw / Mn), the better the heat resistance and image performance (resist profile, defocus latitude, etc.). It becomes. In addition, if unreacted monomer remains, dry etching resistance deteriorates and the transmittance of the resist film decreases, which is not preferable. The unreacted monomer is 2% by weight or less, preferably 1% by weight or less in the polymer.
In addition, the weight average molecular weight and molecular weight distribution (Mw / Mn) of a polymer (A) are measured as a polystyrene conversion value by the gel permeation chromatography which attached the refractive index detector.
[0032]
In the positive photosensitive resin composition of the present invention, the content of the polymer (A) is 50 to 99.7% by weight, preferably 70 to 99% by weight, in terms of solid content.
The positive photosensitive resin composition of the present invention can contain other polymers as required in addition to the polymer (A). The content of the other polymer is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, still more preferably 10 parts by weight or less, and particularly preferably 5 parts by weight or less per 100 parts by weight of the polymer (A). .
[0033]
As said other polymer which the positive photosensitive resin composition of this invention can contain, what is compatible with the alicyclic polymer of this invention should just be sufficient, poly p-hydroxyethylene, hydrogenated poly p-- Hydroxyethylene, novolac resin and the like can be mentioned.
[0034]
Next, (B) a compound (hereinafter also referred to as “(B) photoacid generator”) that decomposes upon irradiation with actinic light and generates an acid contained in the positive photosensitive resin composition of the present invention will be described. To do.
Examples of the photoacid generator (B) used in the present invention include a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or ultraviolet light, A well-known photoacid generator and a mixture thereof are appropriately selected and used for micro photoresists that generate acid by ultraviolet rays, KrF excimer laser light, ArF excimer laser light, electron beam, X-ray, molecular beam, ion beam, etc. can do.
In the present invention, actinic rays are used in a broad concept including radiation as described above.
[0035]
(B) The photoacid generator is not particularly limited as long as it dissolves in the organic solvent described later used in the positive photosensitive resin composition of the present invention, but generates a photoacid that generates an acid with light of 220 nm or less. It is preferable that it is an agent. Moreover, it may be used alone or in combination of two or more kinds, and may be used in combination with an appropriate sensitizer.
[0036]
Examples of usable photoacid generator (B) include triphenylsulfonium salt derivatives described in J. Org. Chem. Vol. 43, N0.15, 3055 (1978) and Japanese Patent Application No. 9-279071. Other onium salts (sulfonium salts, iodonium salts, phosphonium salts, diazonium salts, ammonium salts) described in 1) can also be used.
Specific examples of onium salts include diphenyliodonium triflate, diphenyliodonium pyrenesulfonate, diphenyliodonium dodecylbenzenesulfonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, diphenyliodonium hexafluoroantimonate, triphenylsulfonium naphthalenesulfonate , Triphenylsulfonium camphorsulfonium, (4-methoxyphenyl) phenyliodonium trifluoromethanesulfonate, bis (t-butylphenyl) iodonium trifluoromethanesulfonate, and the like.
[0037]
Also described in JP-A-3-103854, JP-A-3-103856, JP-A-4-210960, diazodisulfones and diazoketosulfones, JP-A-64-18143, JP-A-2-245756 And the disulfones described in JP-A-2-71270 can also be suitably used. Further, USP 3849137, JP 63-26653, JP 62-69263, JP 63-146038, JP 63-163452, JP 62-153853, JP 63-63. A compound in which a group capable of generating an acid by light described in No. 146029 or the like is introduced into the main chain or side chain of a polymer can also be used. JP-A-7-25846, JP-A-7-28237, JP-A-7-92675 No., JP-A-8-27120, aliphatic alkylsulfonium salts having a 2-oxocyclohexyl group, and N-hydroxysuccinimide sulfonates, as well as J. Photopolym. Sci., Tech., Vol. 7, No. 3,423. The sulfonium salt described in (1994) can also be suitably used, and it can be used alone or in combination of two or more.
Of these photoacid generators, onium salts are particularly preferred because of their good resist sensitivity and resolution.
[0038]
The content of these (B) compounds that decompose upon irradiation with actinic rays to generate an acid is usually 0.001 to 40% by weight, preferably based on the total weight (solid content) of the photosensitive resin composition, 0.01 to 20% by weight, more preferably 0.1 to 15% by weight, and particularly preferably 0.5 to 10% by weight. (B) If the amount of the photoacid generator is less than 0.001% by weight, the sensitivity will be low, and if it is more than 40% by weight, the light absorption of the resist will be too high, resulting in profile deterioration and process margins, especially bake margins. It is not preferable.
[0039]
Next, the (C) nitrogen-containing basic compound contained in the positive photosensitive resin composition of the present invention will be described. (C) As the nitrogen-containing basic compound, an organic amine, a basic ammonium salt, a basic sulfonium salt, or the like may be used as long as it does not deteriorate sublimation or resist performance. Among these nitrogen-containing basic compounds, organic amines are preferable in terms of excellent image performance.
For example, JP-A-63-149640, JP-A-5-249662, JP-A-5-127369, JP-A-5-289322, JP-A-5-249683, JP-A-5-289340, JP-A-5-232706 JP-A-5-257282, JP-A-62-242605, JP-A-6-242606, JP-A-6-266100, JP-A-6-266110, JP-A-6-317902, JP-A-7-120929, JP-A-7-65558, JP-A-7-319163, JP-A-7-508840, JP-A-7-333844, JP-A-7-219217, JP-A-7-92678, JP-A-7-28247, Special Kaihei 8-22120, JP-A-8110638, JP-A8-123030, JP-A-9-274312, JP-A-9-66871, JP-A-9-292708, JP-A-9-325496, Special table Basic compounds described in JP-A-7-508840, USP5525453, USP5629134, USP5667938 and the like can be used.
[0040]
As the nitrogen-containing basic compound, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,4-diazabicyclo is preferable. [2.2.2] Octane, 4-dimethylaminopyridine, 1-naphthylamine, piperidine, hexamethylenetetramine, imidazoles, hydroxypyridines, pyridines, 4,4′-diaminodiphenyl ether, pyridinium p-toluenesulfonate, Examples include 2,4,6-trimethylpyridinium p-toluenesulfonate, tetramethylammonium p-toluenesulfonate, tetrabutylammonium lactate, triethylamine, and tributylamine.
Among these, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,4-diazabicyclo [2.2.2] Organic amines such as octane, 4-dimethylaminopyridine, 1-naphthylamine, piperidine, hexamethylenetetramine, imidazoles, hydroxypyridines, pyridines, 4,4′-diaminodiphenyl ether, triethylamine, and tributylamine are preferred.
[0041]
(C) The content of the nitrogen-containing basic compound is usually 0.001 to 10 parts by weight, preferably 0.001 to 5 parts by weight, more preferably 100 parts by weight of the photosensitive resin composition (solid content). Is 0.001 to 0.5 parts by weight. If it is less than 0.001 part by weight, the effect of adding the component (C) cannot be sufficiently obtained. On the other hand, when the amount exceeds 10 parts by weight, the sensitivity is lowered and the developability of the non-exposed part tends to be remarkably deteriorated. (C) A basic compound can be used individually by 1 type or in combination of 2 or more types.
[0042]
In the present invention, the mixing weight ratio ((B) / (C)) in the composition of the (B) photoacid generator and the (C) nitrogen-containing basic compound is preferably in the range of 5 to 300. More preferably, it is the range of 10-200. By setting it within this range, the resist sensitivity and resolving power become better, and the line width dependency (PED dependency) of the pattern due to leaving after exposure can be reduced. That is, by adjusting the mixing weight ratio of (B) and (C), resist sensitivity, resolving power, and PED dependency are compatible.
[0043]
Next, the (D) fluorine-based and / or silicon-based surfactant contained in the positive photosensitive resin composition of the present invention will be described.
The photosensitive resin composition of the present invention may contain any of a fluorine-based surfactant, a silicon-based surfactant, a fluorine atom and a silicon atom-containing surfactant, or two or more thereof.
As these (D) surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540 , JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, and the following commercially available surfactants may be used as they are. it can.
Examples of commercially available surfactants that can be used include F-top EF301 and EF303 (made by Shin-Akita Kasei Co., Ltd.), Florard FC430 and 431 (made by Sumitomo 3M Ltd.), MegaFuck F171, F173, F176, F189 and R08 (Dainippon Ink Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.) and other fluorine-based and / or silicon-based surfactants. . Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon surfactant.
[0044]
(D) The compounding quantity of surfactant is 0.001 weight part-2 weight part normally per 100 weight part of solid content in the composition of this invention, Preferably it is 0.003 weight part-0.10 weight part. is there.
These surfactants can be used alone or in combination of two or more.
[0045]
In the present invention, the weight ratio of the (A) polymer to the (D) surfactant in the composition ((A) / (D)) is preferably in the range of 500 to 20000, more preferably It is the range of 1000-15000. By setting this ratio, developability and line width reproducibility are improved, and the uniformity of the coating film thickness is improved.
Although it is not well understood why the positive photosensitive resin composition of the present invention is specifically superior to the development defects, a combination of (C) a nitrogen-containing basic compound and a specific (D) surfactant It seems that it was expressed by. For example, in a combination of (C) a nitrogen-containing basic compound and a surfactant other than the present invention, such as a nonionic surfactant, the image performance such as the profile is insufficient.
[0046]
The positive photosensitive resin composition of the present invention has a molecular weight of 2000 or less as necessary, a group having a group that can be decomposed by the action of an acid, and an alkali solubility that is increased by the action of an acid. Degradable compounds can be included.
For example, described in Proc. SPIE, 2724, 355 (1996), JP-A-8-15865, USP5310619, USP-5372912, J. Photopolym. Sci., Tech., Vol. 10, No. 3, 511 (1997)). Containing an acid-decomposable group, cholic acid derivative, dehydrocholic acid derivative, deoxycholic acid derivative, lithocholic acid derivative, ursocholic acid derivative, abietic acid derivative, etc. Aromatic compounds such as naphthalene derivatives can be used as the low-molecular acid-decomposable compound.
Further, the low-molecular acid-decomposable dissolution inhibiting compound described in JP-A-6-51519 can also be used in an addition range at a level that does not deteriorate the permeability of 220 nm, and a 1,2-naphthoquinonediazite compound can also be used. .
When the low molecular acid decomposable dissolution inhibiting compound is used in the photosensitive resin composition of the present invention, the content is usually 0.5 to 50 on the basis of 100 parts by weight (solid content) of the photosensitive resin composition. It is used in the range of parts by weight, preferably 0.5 to 40 parts by weight, more preferably 0.5 to 30 parts by weight, particularly preferably 0.5 to 20.0 parts by weight.
Addition of these low molecular acid decomposable dissolution inhibiting compounds not only further improves the development defects, but also improves dry etching resistance.
[0047]
In the positive photosensitive resin composition of the present invention, if necessary, further a dissolution accelerating compound for a developer, an antihalation agent, a plasticizer, a surfactant, a photosensitizer, an adhesion assistant, a crosslinking agent, A photobase generator and the like can be contained.
[0048]
Examples of the dissolution promoting compound that can be used in the present invention include compounds containing two or more phenolic hydroxyl groups described in JP-A-3-206458, one naphthol such as 1-naphthol, or one carboxyl group. Examples thereof include low molecular compounds having a molecular weight of 1000 or less, such as compounds having the above, carboxylic acid anhydrides, sulfonamide compounds and sulfonylimide compounds.
The blending amount of these dissolution promoting compounds is preferably 30% by weight or less, more preferably 20% by weight or less, based on the total weight (solid content) of the composition.
[0049]
As a suitable antihalation agent, a compound that efficiently absorbs irradiated radiation is preferable, and substituted benzenes such as fluorene, 9-fluorenone, and benzophenone; anthracene, anthracene-9-methanol, anthracene-9-carboxyethyl, phenanthrene , Polycyclic aromatic compounds such as perylene and azylene. Of these, polycyclic aromatic compounds are particularly preferred. These antihalation agents exhibit the effect of improving standing waves by reducing the reflected light from the substrate and reducing the influence of multiple reflection in the resist film.
[0050]
A nonionic surfactant can be used in combination for the purpose of improving the coating property of the photosensitive resin composition of the present invention or improving developability.
Nonionic surfactants that can be used in combination include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene sorbitan mono Examples include stearate and sorbitan monolaurate.
[0051]
Moreover, in order to improve the acid generation rate by exposure, a photosensitizer can be added. Suitable photosensitizers include benzophenone, p, p′-tetramethyldiaminobenzophenone, 2-chlorothioxanthone, anthrone, 9-ethoxyanthracene, pyrene, phenothiazine, benzyl, benzoflavine, acetophenone, phenanthrene, benzoquinone, anthraquinone, 1 , 2-naphthoquinone and the like, but are not limited thereto. These photosensitizers can also be used as the antihalation agent.
[0052]
The photosensitive resin composition of the present invention is usually prepared as a solution by dissolving it in a solvent that dissolves each of the above components and then filtering with a filter having a pore size of about 0.05 μm to 0.2 μm. Examples of the solvent used here include ethylene glycol monoethyl ether acetate, cyclohexanone, 2-heptanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether acetate, 3 -Methyl methoxypropionate, ethyl 3-ethoxypropionate, methyl β-methoxyisobutyrate, ethyl butyrate, propyl butyrate, methyl isobutyl ketone, ethyl acetate, isoamyl acetate, ethyl lactate, toluene, xylene, cyclohexyl acetate, diacetone alcohol, N -Methylpyrrolidone, N, N-dimethylformamide, γ-butyrolactone, N, N-dimethylacetamide, etc. It is. These solvents are used alone or in combination. Of these solvents, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether propionate are particularly preferred from the viewpoints of solubility in the composition, coating properties on the substrate, storage stability, and the like. It is preferable that at least one solvent selected from methyl 3-methoxypropionate, ethyl 3-ethoxypropionate and 2-heptanone is contained in an amount of 70% by weight or more in the total solvent.
Further, since the moisture contained in the solvent affects the resist performance, it is preferable that the amount is small.
[0053]
Furthermore, in the photosensitive resin composition of the present invention, it is preferable to reduce metal impurities such as metal and impurity components such as chloro ions to 100 ppb or less. The presence of a large amount of these impurities is not preferable because it causes malfunctions, defects, and a decrease in yield in manufacturing a semiconductor device.
[0054]
The photosensitive resin composition of the present invention is applied onto a substrate by an appropriate application method such as a spinner or a coater, pre-baked (heated before exposure), exposed to exposure light having a wavelength of 220 nm or less through a predetermined mask, and PEB ( A good resist pattern can be obtained by developing after baking after exposure.
The substrate used here may be any substrate that is usually used in semiconductor devices and other manufacturing apparatuses, and examples thereof include a silicon substrate, a glass substrate, and a nonmagnetic ceramic substrate. Further, an additional layer such as a silicon oxide layer, a wiring metal layer, an interlayer insulating film, a magnetic film, an antireflection film layer, or the like may be present on these substrates as necessary. Circuits etc. may be built in. Furthermore, these substrates may be subjected to a hydrophobic treatment according to a conventional method in order to improve the adhesion of the resist film. Examples of suitable hydrophobizing agents include 1,1,1,3,3,3-hexamethyldisilazane (HMDS).
[0055]
The resist film thickness applied on the substrate is preferably in the range of about 0.1 to 10 μm. In the case of ArF exposure, a thickness of about 0.1 to 1.5 μm is recommended.
The resist film applied on the substrate is preferably pre-baked at a temperature of about 60 to 160 ° C. for about 30 to 300 seconds. If the pre-baking temperature is low and the time is short, the residual solvent in the resist film becomes relatively large, which causes an adverse effect such as deterioration of adhesion, which is not preferable. On the other hand, if the pre-baking temperature is high and the time is long, it is not preferable because the components such as the binder and the photoacid generator of the photosensitive resin composition are decomposed.
[0056]
As a device for exposing the pre-baked resist film, a commercially available ultraviolet exposure device, X-ray exposure device, electron beam exposure device, KrF excimer exposure device, ArF excimer exposure device, F ₂ An excimer exposure apparatus or the like is used, and in the present invention, an apparatus using an ArF excimer laser as an exposure light source is particularly preferable.
The post-exposure baking is performed for the purpose of causing elimination of a protecting group using an acid as a catalyst, the purpose of eliminating standing waves, the purpose of diffusing an acid generator or the like into the film, and the like. This post-exposure bake can be performed in the same manner as the previous pre-bake. For example, the baking temperature is about 60 to 160 ° C, preferably about 90 to 150 ° C.
[0057]
Examples of the developer for the photosensitive resin composition of the present invention include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, and diethylamine. Secondary amines such as di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), quaternary ammonium salts such as trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide, pyrrole, piperidine, 1,8 Diazabicyclo - [5.4.0] -7-undecene, 1,5-diazabicyclo - [4.3.0] -5-alkaline aqueous solution of a cyclic amine such as nonane or the like can be used.
[0058]
Furthermore, it should be used even if an appropriate amount of a hydrophilic organic solvent such as alcohols or ketones, a nonionic or anionic surfactant, a cationic surfactant or an antifoaming agent is added to the alkaline aqueous solution. Can do. In addition to the purpose of improving the resist performance, these additives are alkaline for the purpose of improving adhesion to the substrate, reducing the amount of developer used, and reducing defects caused by bubbles during development. Add to aqueous solution.
[0059]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by this.
Synthesis Example 1 (Synthesis of Polymer A)
A hydride of a ring-opening polymer of a norbornene derivative described in JP-A-9-244247 and Example 4 (repeating structural units are described below) was synthesized according to the method described in EP0789278. (Weight average molecular weight 22000)
[0060]
[Formula 4]

[0061]
Synthesis Example 2 (Synthesis of Polymer B)
A hydride of a ring-opening polymer of a norbornene derivative described in JP-A-9-244247 and Example 1 (repeating structural units are described below) was synthesized according to the method described in EP0789278. (Weight average molecular weight 17000)
[0062]
[Chemical formula 5]

[0063]
Synthesis Example 3 (Synthesis of Polymer C)
A copolymer of norbornene, maleic anhydride, t-butyl acrylate and acrylic acid (repeating structural units are described below) was synthesized according to the method described in JP-A-10-10739, Example 7. (Weight average molecular weight 17000, molar ratio of each repeating unit 50/25/25)
[0064]
[Chemical 6]

[0065]
Synthesis Example 4 (Synthesis of Polymer D)
A copolymer of adamantyl methacrylate and t-butyl acrylate (repeated structural units are described below) was synthesized according to the method described in JP-A-7-234511, Example 1. (Weight average molecular weight 5000, molar ratio of each repeating unit 58/42)
[0066]
[Chemical 7]

[0067]
Synthesis Example 5 (Synthesis of acid-decomposable low molecular weight compound a)
A mixture of 122.7 g (0.3 mol) of cholic acid and 120 ml of thionyl chloride was refluxed for 1 hour. Excess thionyl chloride was removed, the resulting solid was dissolved in 150 ml of tetrahydrofuran, 40 g (0.35 mol) of potassium tert-bucitoxide was gradually added, the reaction mixture was refluxed for 6 hours, cooled and poured into water. It is. The resulting solid was collected by filtration, washed with water and dried under reduced pressure. This crude product was recrystallized with n-hexane to obtain tert-butyl cholate (the following formula) in a yield of 70%.
[0068]
[Chemical 8]

[0069]
Examples 1-6, Comparative Examples 1-5
(Preparation of photosensitive resin composition)
In preparing the photosensitive resin component, the components listed in Table 1, that is, the polymers A, B, C, and D synthesized in Synthesis Examples 1 to 4, triphenylsulfonium triflate (PAG-1) as a photoacid generator ), An acid-decomposable low molecular weight compound (compound a) synthesized in Synthesis Example 5, a nitrogen-containing basic compound, a surfactant, and each component of propylene glycol monomethyl ether acetate as a solvent. In Table 1, the dotted line means that the component was not used.
Each component was mixed and then filtered through a 0.1 μm Teflon filter to prepare a photosensitive resin composition.
The amount of each component when used is as follows.
Polymer A, B, C, D 10g
Photoacid generator 0.06g
Acid decomposable low molecular weight compound 0.25g
Nitrogen-containing basic compound 0.04g
Surfactant 0.05g
Solvent 57.4g
About the photosensitive resin composition prepared in this way, the number of development defects and the image performance of the resist were evaluated by the following methods. Table 2 shows the evaluation results of the number of development defects, and Table 3 shows the evaluation results of the image performance.
[0070]
(Evaluation method for the number of development defects)
(1) Number of development defects -I
The photosensitive resin composition was uniformly applied on a silicon substrate subjected to hexamethyldisilazane treatment by a spin coater, and heated and dried on a hot plate at 120 ° C. for 90 seconds to form a 0.50 μm resist film. . This resist film was exposed with ArF excimer laser light through a mask, and immediately after the exposure, it was heated on a hot plate at 110 ° C. for 90 seconds. Further, the resist film was developed with an aqueous 2.38 wt% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried. The number of development defects of the sample with the contact hole pattern thus obtained was measured using a KLA2112 machine (manufactured by KLA Tencor) (Threshold12, Pixcel Size = 0.39).
(2) Number of development defects-II
The number of development defects was measured in the same manner for the heated, developed, rinsed, and dried samples except for not exposing in (1) Number of developed defects -I.
[0071]
(Image evaluation method)
A resist film having a thickness of 0.50 μm was formed in the same manner as (1) Development defect number −I, and this film was exposed, heated, developed, rinsed and dried. Thereafter, the film thickness was measured with a film thickness meter, and the remaining film ratio [(film thickness after treatment / film thickness before treatment) × 100] was calculated.
Further, the formed 0.25 μm line pattern was observed with a scanning electron microscope, and the profile was examined. Those having a rectangular shape are indicated by ○, and those that are not are indicated by ×.
[0072]
[Table 1]

[0073]
Each symbol in Table 1 is as follows.
PAG-1: Triphenylsulfonium triflate
N-1: Hexamethylenetetramine
N-2: 1,5-diazabicyclo [4.3.0] -5-nonene
N-3: 1,8-diazabicyclo [5.4.0] -7-undecene
N-4: 1,4-diazabicyclo [2.2.2] octane
W-1: Megafuck F176 (Dainippon Ink Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Co., Ltd.) (fluorine and silicone)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicone type)
W-4: Polyoxyethylene nonylphenyl ether
S-1: Propylene glycol monomethyl ether acetate
[0074]
[Table 2]

[0075]
[Table 3]

[0076]
As is clear from the results in Tables 2 and 3, the photosensitive resin composition of the present invention had very few development defects and a rectangular profile was formed.
On the other hand, (C) a nitrogen-containing basic compound and (D) Comparative Example 1 and Comparative Example 5 not using a surfactant, (D) a surfactant was used, but (C) a nitrogen-containing basic compound was not used. Although Comparative Example 2 and (C) a nitrogen-containing basic compound were used, (D) Comparative Example 3 not using a surfactant had a large number of development defects. Comparative Example 4 is an example in which a surfactant not specified in the present invention was used, and development defects were relatively small, but the resist profile was inferior.
[0077]
Examples 7 to 14 and Comparative Examples 6 and 7
(Preparation of photosensitive resin composition)
In preparing the photosensitive resin component, the components described in Table 4 below, that is, the polymers B to D synthesized in Synthesis Examples 2 to 4, the above (PAG-1) or triphenylsulfonium par Fluorobutanesulfonate (PAG-2), the acid-decomposable low molecular weight compound synthesized in Synthesis Example 5, the nitrogen-containing basic compound, the surfactant, and the solvent were blended in the types and weight ratios shown in Table-4. What is marked with a dotted line in Table 4 means that the component was not used.
Each component was mixed and then filtered through a 0.1 μm Teflon filter to prepare a photosensitive resin composition. Table-5 shows the ratio of the constituent components of the photosensitive resin composition.
[0078]
[Table 4]

[0079]
PAG-1, N-2, N-3, N-4, W-1, W-2, W-3, W-4, and S-1 are the same as the compounds described in Table 1 above.
PAG-2: Triphenylsulfonium perfluorobutane sulfonate
S-2: Propylene glycol monomethyl ether
S-3: Ethyl lactate
S-4: Ethyl 3-ethoxypropionate
S-5: Propylene glycol monopropyl ether propionate
S-6: 2-Heptanone
[0080]
[Table 5]

[0081]
About the photosensitive resin composition prepared in this way, the number of development defects and the image performance of the resist were evaluated by the following methods. The evaluation results of the number of development defects are shown in Table-6, and the evaluation results of image performance are shown in Table-7.
(Evaluation method of the number of development defects) was carried out by the same method as that shown in Examples 1 to 6 above.
[0082]
(Image evaluation method)
A 600-mm Brewer Science anti-reflective coating DUV-42 was uniformly applied onto a silicon substrate that had been treated with hexamethyldisilazane with a spin coater, dried on a hot plate at 100 ° C for 90 seconds, and then 240 ° C at 190 ° C. Heat drying was performed for 2 seconds. Thereafter, each photosensitive resin composition was applied by a spin coater and dried at 130 ° C. for 90 seconds to form a 0.50 μm resist film. The resist film was exposed with ArF excimer laser light through a mask, and immediately after the exposure, it was heated on a hot plate at 130 ° C. for 90 seconds. Further, the resist film was developed with an aqueous tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a resist line pattern. Thereafter, the film thickness was measured with a film thickness meter, and the remaining film ratio was calculated as described above.
[0083]
Further, the formed 0.25 μm line pattern was observed with a scanning electron microscope, and the profile was examined. A rectangular shape is indicated by ◯, and a tapered shape is indicated by ×. In addition, although it is a rectangle, the thing of a bowl shape is represented by (triangle | delta).
Sensitivity indicates an exposure amount for reproducing a 0.25 μm mask pattern.
The resolving power indicates the limiting resolving power at an exposure amount that reproduces a 0.25 μm mask pattern.
The developability was represented by ○ when the development residue was not observed, and Δ when it was slightly observed.
[0084]
[Table 6]

[0085]
[Table 7]

[0086]
As is clear from the results of Tables 6 and 7, the composition of the present invention having a specific ratio of specific components has very few development defects, and a rectangular profile is formed in each case, and sensitivity, resolution, The developability was excellent.
[0087]
【The invention's effect】
The positive photosensitive resin composition of the present invention has very few development defects, and in particular, when ArF excimer laser light is used as an exposure light source, the sensitivity, resolution and developability are good, and an excellent pattern profile is exhibited. Therefore, it can be effectively used for forming a fine pattern necessary for manufacturing a semiconductor element.

Claims (14)

(A) a polymer having a cycloaliphatic hydrocarbon skeleton and decomposed by the action of an acid to become alkali-soluble,
(B) a compound that generates an acid upon irradiation with actinic rays,
(C) a nitrogen-containing basic compound (excluding diphenylamine), as well,
(D) A positive photosensitive resin composition for ArF exposure, comprising a fluorine-based and / or silicon-based surfactant. 2. The positive photosensitive resin for ArF exposure according to claim 1, wherein the polymer contains at least one of structural units represented by any of the following (a-1) to (a-15). Resin composition.

A and B each independently represent a hydrogen atom, a hydroxyl group, a carboxyl group, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, an alkoxy group or an alkenyl group having 1 to 10 carbon atoms. They may combine to form a ring. X and Y each independently represent a group that decomposes by the action of an acid. The polymer contains at least one of structural units represented by any of the following (b-1) to (b-5), (b-7), or (b-8). The positive photosensitive resin composition for ArF exposure according to claim 1 or 2.

A represents a hydrogen atom, a hydroxyl group, a carboxyl group, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, alkoxy group or alkenyl group having 1 to 10 carbon atoms.
R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. (A) a polymer having a bridged cyclic aliphatic hydrocarbon skeleton and decomposed by the action of an acid to become alkali-soluble,
(B) a compound that generates an acid upon irradiation with actinic rays,
(C) Nitrogen-containing basic compound (excluding diphenylamine) ,
(D) a fluorine-based and / or silicon surfactants, as well,
(E) It contains a solvent, the weight ratio of (B) to (C) ((B) / (C)) is in the range of 5 to 300, and the weight ratio of (A) to (D) ((A) / (D)) is in the range of 500 to 20000, a positive photosensitive resin composition for ArF exposure . The positive photosensitive resin for ArF exposure according to claim 4, wherein the polymer contains at least one of structural units represented by any one of the following (a-2) to (a-14). Resin composition.

A and B each independently represent a hydrogen atom, a hydroxyl group, a carboxyl group, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, an alkoxy group or an alkenyl group having 1 to 10 carbon atoms. They may combine to form a ring. X and Y each independently represent a group that decomposes by the action of an acid. The polymer contains at least one of structural units represented by any of the following (b-1) to (b-3) and (b-5) to (b-8). The positive photosensitive resin composition for ArF exposure according to claim 4 or 5.

A represents a hydrogen atom, a hydroxyl group, a carboxyl group, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, alkoxy group or alkenyl group having 1 to 10 carbon atoms.
R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 7. The positive photosensitive resin for ArF exposure according to claim 4, wherein the weight ratio of (B) to (C) is in the range of 10 to 200. Resin composition. 8. The positive photosensitive resin for ArF exposure according to any one of claims 4 to 7, wherein the weight ratio of (A) to (D) ((A) / (D)) is in the range of 1000 to 15000. Composition. 9. A low molecular acid decomposable compound having a molecular weight of 2000 or less, having a group that can be decomposed by the action of an acid, and having an alkali solubility increased by the action of an acid. The positive photosensitive resin composition for ArF exposure according to any one of the above. The positive type for ArF exposure according to claim 9, wherein the content of the low molecular acid decomposable compound is 0.5 to 20.0 parts by weight with respect to 100 parts by weight of the solid component. Photosensitive resin composition. The positive photosensitive resin composition for ArF exposure according to any one of claims 1 to 10, wherein the compound (B) is an onium salt. The positive photosensitive resin composition for ArF exposure according to any one of claims 1 to 11, wherein the nitrogen-containing basic compound (C) is an organic amine. The solvent (E) is selected from ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether propionate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate and 2-heptanone. The positive photosensitive resin composition for ArF exposure according to any one of claims 4 to 12, comprising at least one selected from the group consisting of 70% by weight or more in the total solvent. A pattern forming method comprising: forming a film from the positive photosensitive resin composition for ArF exposure according to claim 1, and exposing and developing the film.