JP3851440B2 - Positive photosensitive composition - Google Patents

Description

【００１６】
(式中、Ｚ₁ は酸素原子もしくは硫黄原子を表し、Ｚ₂ は水素原子もしくは水酸基を表す。）
（２） さらに酸の作用により分解しうる基を有し、アルカリ溶解性が酸の作用により増大する、分子量が2000以下の低分子酸分解性溶解阻止化合物を含むことを特徴とする前記（１）記載のポジ型感光性組成物。
（３） 露光光源として、220nm以下の波長の遠紫外光を使用することを特徴とする前記（１）又は（２）のいづれかに記載のポジ型感光性組成物。
【００１７】
【発明の実施の形態】
以下、本発明に使用する化合物について詳細に説明する。
まず、本発明における(A)環状脂肪族炭化水素骨格構造を有する、酸の作用により分解しアルカリ可溶性となる重合体としては、従来知られているものを用いることができるが、その重合体の具体例としては、例えば下記(a-1)〜(a-15)で表されるような主鎖に環状脂肪族炭化水素骨格単位を有し、酸の作用により分解する基（酸分解性基ともいう）を有する重合体や、側鎖に環状脂肪族炭化水素骨格を有する下記(b-1)〜(b-7)で表される繰り返し単位と、酸分解性基を有する重合体を挙げることができる。
また、下記(a-1)〜(a-15)、(b-1)〜(b-7)で表される構造単位等の環状脂肪族炭化水素骨格構造を有する構造単位は、本発明の関わる重合体には必須であるが、下記(c-1)〜(c-4)で表される構造単位を共重合成分として含んでもよい。
【００１８】
【化３】

【００１９】
【化４】

【００２０】
前記(a-1)〜(a-15)、(b-1)〜(b-7)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-7)、(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。）
【００２１】
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、ビニル基、アリル基、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。
【００２２】
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。
【００２３】
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。
【００２４】
前記(a-1)〜(a-6)で表される構造単位を有する重合体は、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)やA.Pacreau;Macromol.Chem.,188,2585(1987)および特開昭51-31800号、特開平1-197460号、特開平2-42094号、EP0789278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)や特開昭49-77999号に記載の化合物、具体的にはタングステン及び／また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またはこれらと第三成分とからなる触媒系が用いられる。
【００２５】
上記タングステンおよ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およ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およ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、上記タングステンまたはモリブデンの化合物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。重合活性等を向上させる目的で用いられる第三成分の触媒としては、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、タングステンまた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。
【００２６】
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。使用される溶媒の具体例としては、ペンタン、ヘキサン、ヘプタン、オクタンの様な脂肪族炭化水素、シクロペンタン、シクロヘキサンの様な脂環族炭化水素、ベンゼン、トルエン、キシレンのような芳香族炭化水素、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-ジクロロベンゼンの様なハロゲン化炭化水素ならびにジエチルエーテルおよびテトラヒドロフランの様なエーテル系化合物が挙げられる。
【００２７】
このような開環（共）重合により得られた樹脂を水素化反応により、本発明に用いられる重合体が得られる。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ものを使用することができる。例えば、不均一触媒としては、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、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、不均一触媒を用いるほうが反応活性が高く、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。
水素添加反応は、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】
所定時間反応後、得られた本発明の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。
この様にして得られた本発明の樹脂は、屈折率検知器をつけたゲル浸透クロマトグラフィで、保持時間を分子量既知のポリスチレンと比較して測定され、重量平均分子量が求められる。
【００２９】
前記(a-7)〜(a-15 ）で表される重合体は、例えば、フリーラジカル開始剤の有効量の存在下環状脂肪族炭化水素モノマーのラジカル（共）重合により通常合成できる。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)、US3143533号、US3261815号、US3510461号、US3793501号、US3703501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。通常、開始剤の濃度は単量体の総重量に対して約0.01から10重量%、好ましくは約0.1から５重量%の範囲になる。反応温度は高範囲に変えられ、通常室温から250℃の範囲、好ましくは40℃から200℃の範囲、さらに好ましくは60℃から160℃の範囲である。
【００３０】
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。所定の温度で出発物質を溶解し、また生成物の混合物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、例えばトルエンのような芳香族炭化水素類、酢酸エチルのような脂肪族または芳香族エステル類、およびテトラヒドロフランのような脂肪族エーテル類が挙げられる。
所定時間反応後、得られた本発明の樹脂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。
この様にして得られた本発明に用いられる重合体は、屈折率検知器をつけたゲル浸透クロマトグラフィで、保持時間を分子量既知のポリスチレンと比較して測定され、重量平均分子量が求められる。
【００３１】
（ｂ−１）〜（ｂ−７）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。
本発明に用いられる重合体中、環状脂肪族炭化水素骨格構造を含む繰り返し単位の含有量は全単量体の繰り返し単位に対して、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、本発明に用いられる重合体中、酸分解性基を有する繰り返し単位の含有量は全単量体の繰り返し単位中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。
【００３２】
本発明で用いられる重合体は、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、本発明で用いられる重合体の分散度(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。
【００３３】
本発明において、上記（Ａ）の重合体の感光性組成物（溶媒は除く）中の添加量としては、全固形分に対し50〜99.7重量%、好ましくは70〜99重量%である。
本発明においては、上記本発明における重合体以外に、必要により他のポリマーを併用することもできる。そのような他のポリマーとしては、上記（Ａ）の重合体と相溶するものであればよく、例えばポリｐ−ヒドロキシスチレン、水素化ポリｐ−ヒドロキシスチレン、ノボラック樹脂等が挙げられる。本発明の組成物において、他のポリマーの好ましい使用範囲は、本発明における重合体100重量部あたり、30重量部以下、好ましくは20重量部以下、特に好ましくは10重量部以下の割合で混合できる。
【００３４】
次に、本発明のポジ型感光性組成物における(B)の活性光線または放射線の照射により分解して酸を発生する化合物（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活性光線または放射線の照射により分解して酸を発生する化合物の例としては、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、あるいは紫外線、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、分子線またはイオンビーム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およ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。
【００３５】
これらのうち本発明において使用されるのに好ましいものは、220nm以下の波長の範囲の光で酸を発生する光酸発生剤であることが好ましく、なお、本発明の（Ａ）の重合体との混合物が有機溶剤に十分溶解するものであればいかなる光酸発生剤でもよい。また、単独、もしくは2種以上を混合して用いたり、適当な増感剤と組み合わせて用いてもよい。
使用可能な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。
【００３６】
また、特開平3-103854号、特開平3-103856号、特開平4-1210960号で表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62-692 63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るし、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種以上の組み合わせで用いられる。
【００３７】
これらの活性光線または放射線の照射により分解して酸を発生する化合物の添加量は、感光性組成物の全重量（塗布溶媒を除く）を基準として、通常0.001〜40重量%の範囲で用いられ、好ましくは0.01〜20重量%、更に好ましくは0.1〜5重量%の範囲で使用される。光酸発生剤の添加量が0.001重量%より少ないと感度が低くなり、また、添加量が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(特にベーク)マージンが狭くなり好ましくない。
【００３８】
次に本発明のポジ型感光性組成物に用いられる（Ｃ）上記（式−１）で表される部分構造を有する、分子量が1000以下の複素環状化合物について説明する。
その分子量としては、好ましくは８０〜１０００であり、より好ましくは１００〜８００である。
上記（式−１）で表される部分構造は、
−Ｃ（＝Ｏ）−ＮＨ−、又は
−Ｃ（＝Ｏ）−Ｎ（ＯＨ）−
が好ましい。
このような（Ｃ）の複素環状化合物の例としては、例えば、ｏ−安息香酸スルフイミド、５，５−ジフェニルチオヒダントイン、ヒダントイン、５−メチルチアゾリン−２−チオン、１０−ピリド〔３，２−ｂ〕〔１，４〕−ベンゾチアジン、グリシン無水物、ウラゾール、１−ヒドロキシベンゾトリアゾール、アロキサン、バルビツール酸、マレイミド、アザウラシル、アザシクロノナン−２−オン、及び下記構造式のもの等を挙げることができる。
【００３９】
【化５】

【００４０】
【化６】

【００４１】
【化７】

【００４２】
【化８】

【００４３】
これらの（Ｃ）の化合物の使用量は、感光性組成物(溶媒を除く)100重量部に対し、通常、0.001〜15重量部、好ましくは0.01〜10重量部である。0.001重量部未満では本発明の添加効果が十分得られない。一方、15重量部を越えると残膜率が低下するので好ましくない。これら化合物は２種以上混合して用いることもできる。
【００４４】
また、本発明の効果を損なわない範囲で、本発明の組成物に、低分子の脂肪族非環状カルボン酸や芳香族カルボン酸を混合してもよいが、カルボキシル基を有する重合体、例えばスチレン−アクリル酸共重体、スチレン−メタクリル酸共重合体及びカルボキシル基置換ノルボルネン重合体などのオリゴマー添加は、レジストプロファイルを劣化させるので好ましくない。
【００４５】
次に本発明のポジ型感光性組成物に用いられる（Ｄ）含窒素塩基性化合物について説明する。含窒素塩基性化合物としては、有機アミンや塩基性のアンモニウム塩や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く、室温で液体のアミンであれば高沸点150℃のアミンが好ましく、固体アミンであれば融点が100℃以上のものが特に好ましい。
【００４６】
即ち、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、US5525453号、US5629134号、US5667938号等、に記載の有機アミンや塩基性のアンモニウム塩や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く、室温で液体のアミンであれば高沸点150℃のアミンが好ましく、固体アミンであれば、融点が100℃以上のものが特に好ましい。
【００４７】
具体的には、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、ピペラジン、4,4'-メチレンビス(シクロヘキシルアミン)、トリス(ヒドロキシメチルアミノメタン)、2-アミノ-2-メチル-1,3-プロパンジオール、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、テトラブチルアンモニウムラクテート等が挙げられる。含窒素塩基性化合物の使用量は、感光性組成物(溶媒を除く)100重量部に対し、通常、0.001〜10重量部、好ましくは0.01〜5重量部である。0.001重量部未満では本発明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。これら化合物は、単独で用いても良いし、２種以上混合して用いることもできる。
【００４８】
次に、本発明のポジ型感光性組成物に用いられる（Ｄ）フッソ系及び／またはシリコン系界面活性剤について説明する。
フッソ系界面活性剤及び／またはシリコン系界面活性剤としては、フッ素原子を含有する界面活性剤、ケイ素原子を含有する界面活性剤、又はフッ素原子とケイ素原子の両方を含有する界面活性剤を挙げることができ、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号記載の公知のフッソ系及び／またはシリコン系界面活性剤を挙げることができるし、下記市販の界面活性剤をそのまま用いることもできる。
【００４９】
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 、SC102 、SC103 、SC104 、SC105 、SC106 （旭硝子（株）製）等のフッソ系及び／またはシリコン系界面活性剤、ポリシロキサンポリマーKP-341（信越化学工業（株）製）等を挙げることができる。
これらの界面活性剤のうち、本発明ではフッソ原子とシリコン原子の両方を有する界面活性剤が、現像欠陥の改善の点で特に優れる。
【００５０】
これらの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０．０１重量部〜２重量部、好ましくは０．０１重量部〜１重量部の割合で添加される。
これらの界面活性剤は単独で使用しても良いし、また、いくつかの組み合わせで添加することもできる。
【００５１】
本発明のポジ型感光性組成物が、前記の現像欠陥に対しなぜ特異的に優れるのかは良くわかっていないが、分子量が１０００以下の複素環状化合物と含窒素塩基性化合物と特定の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。例えば前記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、具体的にはノニオン系の界面活性剤などの組み合わせでは、実現できなかった効果である。
【００５２】
本発明のポジ型感光性組成物は必要に応じて酸の作用により分解しうる基を有し、アルカリ溶解性が酸の作用により増大する分子量が2000以下の低分子酸分解性溶解阻止化合物を含むことができる。
例えばProc.SPIE,2724, 355(1996)や特開平8-15865号、US5310619号、US5372912号、J.Photopolym.Sci.,Tech.,Vol.10,No.3,511(1997))に記載されているような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やアビエチン酸誘導体のような脂環族化合物のようなもの、または、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も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220nm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。
【００５３】
本発明において、上記低分子酸分解性溶解阻止化合物を使用する場合、その添加量は感光性組成物の全重量(塗布溶媒を除く)を基準として、通常1〜50重量%の範囲で用いられ、好ましくは3〜40重量%、更に好ましくは5〜30重量%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の改良にも効果があることがわかった。
【００５４】
本発明のポジ型感光性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。
【００５５】
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、これらの内、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。
【００５６】
本発明の感光性組成物は塗布性を改良したり、現像性を改良する目的で下記界面活性剤を併用することができる。このような界面活性剤の例としては、例えば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のノニオン系界面活性剤が挙げられる。
【００５７】
露光による酸発生率を向上させる為、下記に挙げるような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は、具体的にはベンゾフェノン、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-ナフトキノン等であ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。
【００５８】
本発明の感光性組成物は、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整される。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混合して用いられる。溶媒の選択は、前記組成物に対する溶解性や基板への塗布性、保存安定性等に影響するため重要であり、溶媒に含まれる水分もこれらの性能に影響するため、少ない方が好ましい。
【００５９】
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。
【００６０】
上記感光性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良い。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良い。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。
【００６１】
基板上に塗布されるレジスト膜厚は、約0.1μm〜10μmの範囲が好ましく、ArF露光の場合は、0.1μm〜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。
【００６２】
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。
【００６３】
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。
【００６４】
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およ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。
【００６５】
【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、第４例に記載のノルボルネン誘導体の開環重合体を水素化した重合体（下記構造）をEP0789278号記載の方法に従って合成した。重量平均分子量は２２０００であった。
【００６６】
【化９】

【００６７】
〔合成例２〕重合体Ｂの合成：
特開平9-244247号、第１例に記載のノルボルネン誘導体の開環重合体を水素化した重合体（下記構造）をEP0789278号記載の方法に従って合成した。重量平均分子量は１７０００であった。
【００６８】
【化１０】

【００６９】
〔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-ブチルおよびアクリル酸の共重合体（下記構造）を特開平10-10739号、第７例に記載の方法に従って合成した。重量平均分子量は７４０００であり、各繰り返し単位のモル比は（下記式の左から）５０／２５／２５である。
【００７０】
【化１１】

【００７１】
〔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-ブチルの共重合体を特開平7-234511号、第１例に記載の方法に従って合成した。重量平均分子量は５０００であり、各繰り返し単位のモル比は（下記式の左から）５８／４２である。
【００７２】
【化１２】

【００７３】
〔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、冷却し次いで水中に注いだ。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。この精製物を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。
【００７４】
【化１３】

【００７５】
〔実施例、比較例〕（現像欠陥数の評価)
前記合成例１〜４で得られた樹脂 10g、
トリフェニルスルホニウムトリフレート（ＰＡＧ−１） 0.06g、
複素環状化合物 0.25g、
酸分解性低分子化合物 0.5g、
含窒素塩基性化合物 0.10g、
界面活性剤 0.05g、
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 57.4g
を表-1における組成で配合した感光性組成物を0.1μmのテフロンフィルターにより濾過した。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110℃で90秒間ホットプレート上で加熱した。更に2.38%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。
【００７６】
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KLAテンコール（株）製KLA2112機により現像欠陥数を測定(Threshold12 ,Pixcel Size=0.39)した（現像欠陥数−Ｉ）。
なお、比較のために露光しないで現像、リンスしたサンプルについても同様にして現像欠陥数を測定(Threshold12,Pixcel Size=0.39)した（現像欠陥数−II）。結果を表-2に示す。
【００７７】
【表１】

【００７８】
PAG-1:トリフェニルスルホニウムトリフレート
H-1:ベンゾオキサジン
H-2:フタラゾン
H-3:サッカリン
H-4:ベンゾキサゾリノン
H-5:ベンゾチアゾロン
H-6:ローダニン
H-7:ベンズアミド
H-8:ベンズアニリド
H-9:N-メチル-2-ピロリドン
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
N-5:トリエチルアミン
W-1:メガファックF176（大日本インキ（株）製）（フッ素系界面活性剤）
W-2:メガファックR08(大日本インキ（株）製）（フッ素及びシリコン系界面活性剤）
W-3:ポリシロキサンポリマーKP-341（信越化学工業（株）製）（シリコン系界面活性剤）
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
【００７９】
【表２】

【００８０】
表-2の結果から明らかなように本発明の組成物は、いづれも現像欠陥が極めて少なかった。
【００８１】
【発明の効果】
以上示したことから明らかな様に、本発明のポジ型感光性組成物は、現像欠陥が極めて少ない。このため特にArFエキシマレーザー光を露光光源とする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 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 microfabrication of a semiconductor element using a short-wavelength light energy beam such as deep ultraviolet rays, X-rays, and electron beams, and particularly a semiconductor using an ArF excimer laser. The present invention relates to a positive photosensitive 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 range, 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, to manufacture DRAMs with a degree of integration up to 64 Mbits, the 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 (193nm), F ₂ Use of excimer laser (157 nm), X-rays, and electron beams is considered to be effective (Takumi Ueno, “Short-wavelength photoresist materials-Fine processing for ULSI”, Bunshin Publishing, 1988) .
[0003]
In particular, ArF excimer laser is positioned as the next-generation exposure technology, and it is desired to develop a resist with high sensitivity, high resolution, and excellent dry etching resistance for ArF excimer laser exposure.
As resist materials for conventional i-line and KrF excimer laser exposure, in order to obtain high dry etch resistance, resists containing aromatic polymers are widely used. 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 was not 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. Thus, 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) shows 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. In recent years, the use of the polymer has been actively researched.
[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 acrylic 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, such as 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. A compound linked to is disclosed Yes.
[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, EP794458 and EP789278 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]
In addition, defects caused by the lithography process are one of the major causes of yield reduction, and have recently become particularly important problems.
For example, it is said that development defects are generally caused by bubbles at the time of liquid accumulation and microbubbles caused by dissolved gas in the developer (Hirano et al .; 42nd JSAP lecture meeting 27p-ZW -9 (1996)). As the diameter of wafers has recently increased and the amount of developer discharged increases, countermeasures against bubbles have become more important.
As countermeasures against 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.
[0008]
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 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 as described above, but they may even be counterproductive. Until now, there has been no guideline for improving how to deal with development defects. Moreover, if the hydrophilicity of the resist is improved in order to reduce development defects, there is a tendency for the remaining film ratio and profile to deteriorate, making it difficult to achieve compatibility.
[0009]
Furthermore, in the positive chemical amplification system resist for KrF using a conventional aromatic polymer, 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.
[0010]
As means for solving these problems, a technique for adding a basic compound such as 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, JP-A-5-289322, JP-A-5-249683, JP-A-5-289340, JP-A-5-232706, JP-A-5-257282, JP-A-62-242605, Special Kaihei 6-242606, 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-7-319163 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-811038, JP-A-8 -123030, JP-A-9-274312, JP-A-9-66871, JP-A-9-292708, JP-A-9-325496, JP 7-508840, US5525453, US5629134, US5667938, etc. Many are disclosed in the official gazettes.
However, when these amines are added to a chemically amplified resist for ArF using a non-aromatic polymer having a cycloaliphatic hydrocarbon skeleton structure, it is certainly the same as with a non-aromatic polymer. However, the development defects are extremely inferior, and countermeasures are desired.
[0011]
On the other hand, for the purpose of improving sensitivity and resist pattern shape, adding a carboxylic acid compound to a chemically amplified resist composition for excimer laser light for KrF is disclosed in JP-A-7-92679 and JP-A-5-181279. Further, JP-A-6-214391, JP-A-9-5987, and WO94 / 01805 disclose the addition of an amide compound or an imide compound.
[0012]
Japanese Patent Application Laid-Open No. 9-6001 is well known in that an amine and a carboxylic acid compound are added to provide excellent sensitivity and resolving power and to improve the aging stability between exposure and PEB. However, strong basic low-boiling amines (for example, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine) and aromatic carboxylic acids (for example, salicylic acid, nitrobenzoic acid) disclosed as preferred in JP-A-9-6001 are preferred. (Acid, phthalic acid) is added to a chemically amplified resist for ArF using a non-aromatic polymer having a cycloaliphatic hydrocarbon skeleton structure, and certainly an excimer laser for KrF using a non-aromatic polymer. As in the case of the chemically amplified resist composition for light, although an effect is seen with respect to the stability over time between exposure and PEB, the development defects are extremely inferior, and countermeasures have been desired. In addition, amines with low boiling points tend to evaporate during PEB, so the addition effect of amines is not expressed at all, and equipment used for semiconductor production such as hot plates is contaminated with amines. Was causing problems.
[0013]
[Problems to be solved by the invention]
The object of the present invention has been made in view of the above problems, and is a positive type that has excellent residual film ratio and resist profile, and does not cause a problem of development defects, especially for deep ultraviolet rays, especially ArF excimer laser light. It is to provide a photosensitive composition.
[0014]
[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, and a molecular weight of a specific structure of 1000 or less. Knowing that the object can be achieved by a combination of a nitrogen-containing basic compound, a fluorine-based and / or silicon-based surfactant, and a solvent, the present invention has been achieved. That is, the present inventor is achieved by the method having the following configuration.
(1) (A) a polymer containing a cyclic aliphatic hydrocarbon skeleton structure, which is decomposed by the action of an acid and becomes alkali-soluble,
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) a heterocyclic compound having a partial structure represented by the following (formula-1) and having a molecular weight of 1000 or less,
(D) a nitrogen-containing basic compound, and
(E) Fluoro-based and / or silicon-based surfactant
A positive photosensitive composition comprising:
[0015]
[Chemical 2]

[0016]
(Where Z ₁ Represents an oxygen atom or a sulfur atom, and Z ₂ Represents a hydrogen atom or a hydroxyl group. )
(2) Further comprising a low molecular acid decomposable dissolution inhibiting 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. ) Positive photosensitive composition.
(3) The positive photosensitive composition as described in either (1) or (2) above, wherein far ultraviolet light having a wavelength of 220 nm or less is used as an exposure light source.
[0017]
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. As specific examples, 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 group) And polymers having a repeating unit represented by the following (b-1) to (b-7) having a cyclic aliphatic hydrocarbon skeleton in the side chain, and an acid-decomposable group. be able to.
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-7) Although essential for the polymer concerned, structural units represented by the following (c-1) to (c-4) may be included as a copolymerization component.
[0018]
[Chemical 3]

[0019]
[Formula 4]

[0020]
In the structural units represented by (a-1) to (a-15) and (b-1) to (b-7), 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-7) 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. )
[0021]
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 vinyl group, allyl 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.
[0022]
As the group capable of decomposing by the action of an acid, — (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.
[0023]
Examples of the further substituent in each of the above groups include a halogen atom, a cyano group, and a nitro group.
[0024]
The polymer having the structural units represented by (a-1) to (a-6) is, for example, ring-opening polymerization of cyclic olefins in the presence of a metathesis catalyst in an organic solvent or a non-organic solvent. Can be obtained. Ring-opening (co) polymerization is described, for example, in WLTruett et al .; J. Am. Chem. Soc., 82, 2337 (1960) and A. Pacreau; Macromol. Chem., 188, 2585 (1987) and JP-A-51-31800. No. 1, JP-A-1-197460, JP-A-2-42094, EP0789278 and the like. The metathesis catalyst used here is, for example, a compound described in the Society of Polymer Science: Synthesis and Reaction of Polymers (1), Kyoritsu Shuppan p375-381 (1992) and JP-A-49-77999, specifically 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 is used.
[0025]
Specific examples of the tungsten and molybdenum compounds include molybdenum pentachloride, tungsten hexachloride and tungsten oxytetrachloride. Examples of the organoaluminum compound include triethylaluminum, triisobutylaluminum, trihexylaluminum, diethylaluminum monochloride, -n-butylaluminum monochloride, ethylaluminum sesquichloride, diethylaluminum monobutoxide and triethylaluminum-water (molar ratio 1: 0.5). In the ring-opening polymerization, the ratio of the organoaluminum compound used relative to 1 mol of the tungsten or molybdenum compound is preferably 0.5 mol or more. Catalysts for the third component used for the purpose of improving polymerization activity include water, hydrogen peroxide, oxygen-containing organic compounds, nitrogen-containing organic compounds, halogen-containing organic compounds, phosphorus-containing organic compounds, sulfur-containing organic compounds, metals The organic compound is included, and is used in a proportion of 5 mol or less per 1 mol of tungsten or molybdenum compound. The ratio of the catalyst to the monomer is usually 0.1 to 20 moles per 100 moles of the monomer, although it depends on the type of the catalyst.
[0026]
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. Specific examples of the solvent used include aliphatic hydrocarbons such as pentane, hexane, heptane and octane, alicyclic hydrocarbons such as cyclopentane and cyclohexane, and aromatic hydrocarbons such as benzene, toluene and xylene. , Halogenated hydrocarbons such as methylene chloride, 1,1-dichloroethane, 1,2-dichloroethylene, 1-chloropropane, 1-chlorobutane, 1-chloropentane, chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene And ether compounds such as diethyl ether and tetrahydrofuran.
[0027]
A polymer used in the present invention is obtained by hydrogenating a resin obtained by such ring-opening (co) polymerization. As the catalyst used in the hydrogenation reaction, those used in the usual hydrogenation reaction of olefinic compounds can be used. For example, the heterogeneous catalyst includes 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. Uniform 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, it is advantageous to use a heterogeneous catalyst because the reaction activity is high, catalyst removal after the reaction is easy, and the resulting polymer is not colored.
The hydrogenation reaction can be carried out at 0 to 200 ° C., preferably 20 to 180 ° C. in a hydrogen gas atmosphere at normal pressure to 300 atm, preferably 3 to 200 atm. The hydrogenation rate is usually 50% or more, preferably 70% or more, 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]
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 of the present invention from unreacted monomer components, solvents and the like.
The resin of the present invention thus obtained is measured by gel permeation chromatography equipped with a refractive index detector by comparing the retention time with polystyrene having a known molecular weight, and the weight average molecular weight is obtained.
[0029]
The polymers represented by the above (a-7) to (a-15) can be usually synthesized by, for example, radical (co) polymerization of a cyclic aliphatic hydrocarbon monomer in the presence of an effective amount of a free radical initiator. Specifically, J. Macromol. Sci. Chem. A-5 (3) 491 (1971), A-5 (8) 1339 (1971), Polym. Lett. Vol. 2,469 (1964), US3143533, It can be synthesized by the methods described in US3261815, US3510461, US3793501, US3703501, 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. Usually, the concentration of the initiator will be in the range of about 0.01 to 10% by weight, preferably about 0.1 to 5% by weight, based on the total weight of the monomers. The reaction temperature is changed to a high range, and is usually in the range of room temperature to 250 ° C, preferably in the range of 40 ° C to 200 ° C, more preferably in the range of 60 ° C to 160 ° C.
[0030]
The polymerization or copolymerization is preferably performed in an organic solvent. A solvent that dissolves the starting material at a given temperature and also dissolves the mixture of products is preferred. The preferred solvent varies depending on the type of monomer to be copolymerized, but for example aromatic hydrocarbons such as toluene, aliphatic or aromatic esters such as ethyl acetate, and aliphatic ethers such as tetrahydrofuran. Kind.
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 resin of the present invention from unreacted monomer components, solvents and the like.
The polymer used in the present invention thus obtained is measured by gel permeation chromatography equipped with a refractive index detector and compared with polystyrene having a known molecular weight to determine the weight average molecular weight.
[0031]
Polymers having the structural units (b-1) to (b-7) 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 used in the present invention, the content of the repeating unit containing a cyclic aliphatic hydrocarbon skeleton structure is preferably 10 mol% or more, more preferably 20 mol% or more, based on the repeating units of all monomers. More preferably, it is 30 mol% or more.
Further, in the polymer used in the present invention, the content of the repeating unit having an acid-decomposable group is 10 to 90 mol%, preferably 15 to 85 mol%, more preferably in the repeating units of all monomers. 20 to 80 mol%.
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%.
[0032]
The polymer used in the present invention 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. In addition, the degree of dispersion (Mw / Mn) of the polymer used in the present invention is preferably 1.0 to 6.0, more preferably 1.0 to 4.0, and the smaller the heat resistance and image performance (resist profile, defocus latitude, etc.). It becomes.
[0033]
In the present invention, the amount of the polymer (A) added in the photosensitive composition (excluding the solvent) is 50 to 99.7% by weight, preferably 70 to 99% by weight, based on the total solid content.
In the present invention, in addition to the polymer in the present invention, other polymers may be used in combination as necessary. As such another polymer, what is necessary is just what is compatible with the polymer of said (A), For example, poly p-hydroxy styrene, hydrogenated poly p-hydroxy styrene, a novolak resin etc. are mentioned. In the composition of the present invention, the preferred range of use of the other polymer is 30 parts by weight or less, preferably 20 parts by weight or less, particularly preferably 10 parts by weight or less per 100 parts by weight of the polymer in the present invention. .
[0034]
Next, the compound (also referred to as a photoacid generator) that generates an acid upon decomposition by irradiation with actinic rays or radiation (B) in the positive photosensitive composition of the present invention will be described.
Examples of compounds that are decomposed by irradiation with actinic rays or radiation used in the present invention include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, Photo-discoloring agents, or photo-acid generators known for micro photoresists that generate acids by ultraviolet rays, far-ultraviolet rays, KrF excimer laser beams, ArF excimer laser beams, electron beams, X-rays, molecular beams, or ion beams, and mixtures thereof Can be appropriately selected and used.
[0035]
Of these, preferred for use in the present invention is preferably a photoacid generator that generates an acid with light having a wavelength of 220 nm or less, and the polymer (A) of the present invention Any photoacid generator may be used as long as the mixture is sufficiently soluble in an organic solvent. Further, they may be used alone or in combination of two or more, or may be used in combination with an appropriate sensitizer.
Examples of usable photoacid generators 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) 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.
[0036]
Further, diazodisulfones and diazoketosulfones represented by JP-A-3-103854, JP-A-3-103856, JP-A-4-210960, JP-A-64-18143, JP-A-2-245756 The described iminosulfonates and the disulfones described in JP-A-2-71270 can also be suitably used. Further, USP 3849137, JP 63-26653, JP 62-692 63, JP 63-146038, JP 63-163452, JP 62-153853, JP 63 As described in JP-A-746029, a compound in which a group capable of generating an acid by light is introduced into the main chain or side chain of a polymer can be used, and JP-A-7-25846, JP-A-7-28237, JP-A-7 -92675, 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. Sulphonium salts described in .3,423 (1994) can also be suitably used, and are used alone or in combination of two or more.
[0037]
The addition amount of these compounds that decompose upon irradiation with actinic rays or radiation to generate an acid is usually used in the range of 0.001 to 40% by weight based on the total weight of the photosensitive composition (excluding the coating solvent). It is preferably used in the range of 0.01 to 20% by weight, more preferably 0.1 to 5% by weight. If the amount of photoacid generator added is less than 0.001% by weight, the sensitivity will be low, and if the amount added is more than 40% by weight, the light absorption of the resist will be too high and profile deterioration and process (especially baking) margin will be narrow It is not preferable.
[0038]
Next, (C) a heterocyclic compound having a partial structure represented by the above (formula-1) and having a molecular weight of 1000 or less, which is used in the positive photosensitive composition of the present invention, will be described.
The molecular weight is preferably 80 to 1000, and more preferably 100 to 800.
The partial structure represented by the above (formula-1) is
-C (= O) -NH-, or
-C (= O) -N (OH)-
Is preferred.
Examples of the heterocyclic compound (C) include o-benzoic acid sulfimide, 5,5-diphenylthiohydantoin, hydantoin, 5-methylthiazoline-2-thione, 10-pyrido [3,2- b] [1,4] -benzothiazine, glycine anhydride, urazole, 1-hydroxybenzotriazole, alloxan, barbituric acid, maleimide, azauracil, azacyclononan-2-one, and those having the structural formula shown below. .
[0039]
[Chemical formula 5]

[0040]
[Chemical 6]

[0041]
[Chemical 7]

[0042]
[Chemical 8]

[0043]
The amount of the compound (C) to be used is generally 0.001 to 15 parts by weight, preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the photosensitive composition (excluding the solvent). If it is less than 0.001 part by weight, the effect of the present invention cannot be obtained sufficiently. On the other hand, if the amount exceeds 15 parts by weight, the remaining film ratio decreases, which is not preferable. These compounds can also be used as a mixture of two or more.
[0044]
In addition, a low molecular weight aliphatic acyclic carboxylic acid or aromatic carboxylic acid may be mixed in the composition of the present invention within a range not impairing the effects of the present invention. -Addition of oligomers such as acrylic acid copolymer, styrene-methacrylic acid copolymer and carboxyl group-substituted norbornene polymer is not preferable because it deteriorates the resist profile.
[0045]
Next, the nitrogen-containing basic compound (D) used in the positive photosensitive composition of the present invention will be described. As the nitrogen-containing basic compound, an organic amine, a basic ammonium salt, a sulfonium salt, or the like is used, as long as it does not deteriorate sublimation or resist performance. If it is a liquid amine at room temperature, it has a high boiling point of 150 ° C. An amine is preferred, and a solid amine having a melting point of 100 ° C. or higher is particularly preferred.
[0046]
That is, 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-66-266110, JP-A-6-317902, JP-A-7-120929 JP, 7-65558, JP 7-319163, JP 7-508840, JP 7-333844, JP 7-219217, JP 7-92678, JP 7-28247, JP-A-8-22120, JP-A-8110638, JP-A-8-123030, JP-A-9-274312, JP-A-9-66871, JP-A-9-292708, JP-A-9-325496, Special Table 7-7508840, US5525453, US5629134, US5667938, etc., organic amines, basic ammonium salts and sulfonium salts are used, as long as they do not deteriorate sublimation or resist performance, If it is a liquid amine, an amine with a high boiling point of 150 ° C. is preferable, and a solid If Min, melting point is particularly preferably not less than 100 ° C..
[0047]
Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,4-diazabicyclo [2.2.2] octane, 4-dimethyl Aminopyridine, 1-naphthylamine, piperidine, hexamethylenetetramine, imidazoles, piperazine, 4,4'-methylenebis (cyclohexylamine), tris (hydroxymethylaminomethane), 2-amino-2-methyl-1,3-propane Examples thereof include diol, 4,4′-diaminodiphenyl ether, pyridinium p-toluenesulfonate, 2,4,6-trimethylpyridinium p-toluenesulfonate, tetramethylammonium p-toluenesulfonate, tetrabutylammonium lactate and the like. The usage-amount of a nitrogen-containing basic compound is 0.001-10 weight part normally with respect to 100 weight part of photosensitive compositions (except a solvent), Preferably it is 0.01-5 weight part. If it is less than 0.001 part by weight, the effect of the present invention cannot be obtained sufficiently. On the other hand, if it exceeds 10 parts by weight, the sensitivity tends to decrease and the developability of the non-exposed part tends to deteriorate significantly. These compounds may be used alone or in combination of two or more.
[0048]
Next, the (D) fluorine-based and / or silicon-based surfactant used in the positive photosensitive composition of the present invention will be described.
Examples of the fluorosurfactant and / or silicon surfactant include a surfactant containing a fluorine atom, a surfactant containing a silicon atom, or a surfactant containing both a fluorine atom and a silicon atom. 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- No. 230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, and the like, and the following commercially available surfactants may be mentioned. Can be used as they are.
[0049]
For example, F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), Megafuck F171, F173, F176, F189, R08 (manufactured by Dainippon Ink Co., Ltd.) Fluoro-based and / or silicon-based surfactant such as Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (Asahi Glass Co., Ltd.), polysiloxane polymer KP-341 (Shin-Etsu Chemical Co., Ltd.) Manufactured).
Among these surfactants, in the present invention, surfactants having both fluorine atoms and silicon atoms are particularly excellent in terms of improving development defects.
[0050]
The amount of these surfactants added is usually 0.01 to 2 parts by weight, preferably 0.01 to 1 part by weight per 100 parts by weight of the solid content in the composition of the present invention. Is done.
These surfactants may be used alone, or may be added in several combinations.
[0051]
Although it is not well understood why the positive photosensitive composition of the present invention is specifically superior to the development defects, a heterocyclic compound having a molecular weight of 1000 or less, a nitrogen-containing basic compound, and a specific surfactant It seems that it was expressed by the combination of. For example, it is an effect that cannot be realized by a combination of the nitrogen-containing basic compound and a surfactant other than the present invention, specifically, a combination of a nonionic surfactant or the like.
[0052]
The positive photosensitive composition of the present invention comprises a low molecular acid-decomposable dissolution inhibiting compound having a group that can be decomposed by the action of an acid, if necessary, and having a molecular weight of 2000 or less whose alkali solubility is increased by the action of an acid. Can be included.
For example, Proc. SPIE, 2724, 355 (1996) and JP-A-8-15865, US5310619, US5372912, J. Photopolym. Sci., Tech., Vol. 10, No. 3, 511 (1997)). Such as alicyclic compounds such as cholic acid derivatives, dehydrocholic acid derivatives, deoxycholic acid derivatives, lithocholic acid derivatives, ursocholic acid derivatives and abietic acid derivatives, Aromatic compounds such as naphthalene derivatives containing an acid-decomposable group can also be used.
Further, the low-molecular acid-decomposable dissolution inhibiting compounds described in JP-A-6-51519 can be used in an addition range at a level that does not deteriorate the permeability at 220 nm, and 1,2-naphthoquinonediazite compounds can also be used.
[0053]
In the present invention, when the low molecular acid-decomposable dissolution inhibiting compound is used, its addition amount is usually used in the range of 1 to 50% by weight based on the total weight of the photosensitive composition (excluding the coating solvent). , Preferably 3 to 40% by weight, more preferably 5 to 30% by weight.
It has been found that the addition of these low molecular acid-decomposable dissolution inhibiting compounds not only further improves the development defects, but also improves dry etching resistance.
[0054]
If necessary, the positive photosensitive composition of the present invention further contains a compound that promotes dissolution in a developer, an antihalation agent, a plasticizer, a surfactant, a photosensitizer, an adhesion aid, a crosslinking agent, and a photobase generator. An agent etc. can be contained.
[0055]
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, and the like. Among these, polycyclic aromatic compounds are particularly preferable. 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.
[0056]
In the photosensitive composition of the present invention, the following surfactants can be used in combination for the purpose of improving coatability and improving developability. Examples of such surfactants include, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxy Nonionic surfactants such as ethylene sorbitan monostearate and sorbitan monolaurate are listed.
[0057]
In order to improve the acid generation rate by exposure, the following photosensitizers can be added. Specific examples of 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.
[0058]
The photosensitive composition of the present invention is prepared as a solution by dissolving it in a solvent that dissolves each of the above components and then filtering it 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 and the like. These solvents are used alone or in combination. The selection of the solvent is important because it affects the solubility in the composition, the coating property to the substrate, the storage stability, and the like, and the moisture contained in the solvent also affects these performances.
[0059]
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 these impurities is not preferable because it causes a malfunction, a defect, and a decrease in yield in manufacturing a semiconductor device.
[0060]
The photosensitive composition is applied onto a substrate by an appropriate application method such as a spinner or a coater, pre-baked (heated before exposure), exposed with exposure light having a wavelength of 220 nm or less through a predetermined mask, and PEB (post-exposure baking). ) And developing, a good resist pattern can be obtained.
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 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).
[0061]
The resist film thickness to be applied on the substrate is preferably in the range of about 0.1 μm to 10 μm. In the case of ArF exposure, a thickness of 0.1 μm 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 composition are decomposed.
[0062]
Commercially available UV exposure equipment, X-ray exposure equipment, electron beam exposure equipment, KrF excimer exposure equipment, ArF excimer exposure equipment, F can be used to expose the resist film after pre-baking. ₂ An excimer exposure apparatus or the like is used. 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 60-160 ° C, preferably about 90-150 ° C.
[0063]
Developers of the photosensitive resin composition of the present invention include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, aqueous ammonia, primary amines such as ethylamine and n-propylamine, 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-Undese , 1,5-diazabicyclo - [4,3,0] -5-alkaline aqueous solution of a cyclic amine such as nonane, etc. can be used.
[0064]
Furthermore, it should be used even if an appropriate amount of a hydrophilic organic solvent such as alcohols or ketones, nonionic or anionic surfactants, cationic surfactants or antifoaming agents 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.
[0065]
【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 polymer obtained by hydrogenating a ring-opening polymer of a norbornene derivative described in JP-A-9-244247 and Example 4 (the following structure) was synthesized according to the method described in EP0789278. The weight average molecular weight was 22000.
[0066]
[Chemical 9]

[0067]
[Synthesis Example 2] Synthesis of Polymer B:
A polymer obtained by hydrogenating a ring-opening polymer of a norbornene derivative described in JP-A-9-244247, Example 1 (the following structure) was synthesized according to the method described in EP0789278. The weight average molecular weight was 17000.
[0068]
[Chemical Formula 10]

[0069]
[Synthesis Example 3] Synthesis of Polymer C:
A copolymer of norbornene, maleic anhydride, t-butyl acrylate and acrylic acid (the following structure) was synthesized according to the method described in JP-A-10-10739, Example 7. The weight average molecular weight is 74000, and the molar ratio of each repeating unit is 50/25/25 (from the left of the following formula).
[0070]
Embedded image

[0071]
[Synthesis Example 4] Synthesis of Polymer D:
A copolymer of adamantyl methacrylate and t-butyl acrylate was synthesized according to the method described in JP-A-7-234511, Example 1. The weight average molecular weight is 5000, and the molar ratio of each repeating unit is 58/42 (from the left of the following formula).
[0072]
Embedded image

[0073]
[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 and the resulting solid was dissolved in 150 ml tetrahydrofuran, 40 g (0.35 mol) potassium-t-butoxide was added slowly, the reaction mixture was refluxed for 6 hours, cooled and poured into water. The resulting solid was collected by filtration, washed with water and dried under reduced pressure. The purified product was recrystallized from n-hexane to obtain cholic acid-t-butyl (the following formula) in a yield of 70%.
[0074]
Embedded image

[0075]
[Examples and Comparative Examples] (Evaluation of the number of development defects)
10 g of the resin obtained in Synthesis Examples 1 to 4,
0.06 g of triphenylsulfonium triflate (PAG-1),
0.25 g of a heterocyclic compound,
0.5g of acid decomposable low molecular weight compound,
0.10 g of nitrogen-containing basic compound,
Surfactant 0.05g,
Propylene glycol monomethyl ether acetate as solvent 57.4g
The photosensitive composition formulated with the composition shown in Table 1 was filtered through a 0.1 μm Teflon filter. It was uniformly coated on a silicon substrate subjected to hexamethyldisilazane treatment with a spin coater and dried on a hot plate at 120 ° 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 110 ° C. for 90 seconds. Further, it was developed with a 2.38% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried.
[0076]
The number of development defects was measured (Threshold12, Pixcel Size = 0.39) (development defect number-I) for the sample with the contact hole pattern obtained in this way using a KLA2112 machine manufactured by KLA Tencor.
For comparison, the number of development defects was also measured in the same manner for samples developed and rinsed without exposure (Threshold 12, Pixel Size = 0.39) (development defect number-II). The results are shown in Table-2.
[0077]
[Table 1]

[0078]
PAG-1: Triphenylsulfonium triflate
H-1: Benzoxazine
H-2: phthalazone
H-3: Saccharin
H-4: Benzoxazolinone
H-5: Benzothiazolone
H-6: Rhodanine
H-7: Benzamide
H-8: Benzanilide
H-9: N-methyl-2-pyrrolidone
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
N-5: Triethylamine
W-1: Megafuck F176 (Dainippon Ink Co., Ltd.) (Fluorosurfactant)
W-2: Megafuck R08 (Dainippon Ink Co., Ltd.) (fluorine and silicon surfactant)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicone surfactant)
W-4: Polyoxyethylene nonylphenyl ether
S-1: Propylene glycol monomethyl ether acetate
[0079]
[Table 2]

[0080]
As is apparent from the results in Table 2, all of the compositions of the present invention had very few development defects.
[0081]
【The invention's effect】
As is apparent from the above, the positive photosensitive composition of the present invention has very few development defects. For this reason, it can be effectively used for forming a fine pattern necessary for manufacturing a semiconductor element using ArF excimer laser light as an exposure light source.

Claims (4)

(A) a polymer containing a cycloaliphatic hydrocarbon skeleton structure, which is decomposed by the action of an acid and becomes alkali-soluble,
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) a heterocyclic compound having a partial structure represented by the following (formula-1) and having a molecular weight of 1000 or less,
A positive photosensitive composition comprising (D) a nitrogen-containing basic compound and (E) a fluorine-based and / or silicon-based surfactant.

(In the formula, Z ₁ represents an oxygen atom or a sulfur atom, and Z ₂ represents a hydrogen atom or a hydroxyl group.)   2. The positive electrode according to claim 1, further comprising a low-molecular acid-decomposable dissolution inhibiting compound 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 and having a molecular weight of 2000 or less. Type photosensitive composition.   3. The positive photosensitive composition according to claim 1, wherein far ultraviolet light having a wavelength of 220 nm or less is used as an exposure light source.   A pattern forming method comprising: forming a film from the positive photosensitive composition according to claim 1; and exposing and developing the film.