JP2004177668A - Base layer film forming material for multilayer resist process, and wiring formation method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base layer film material for a multilayer resist process which is excellent in durability against a photoresist developer solution, is removable by using a photoresist stripping liquid after used, and facilitates the rework of the substrate, and to provide a wiring formation method using the base layer film material. <P>SOLUTION: The base layer film material is prepared by incorporating as a resin component a resin having at least a substituent which leaves the end group to produce a sulfonic acid residue when specified energy is applied. As for the resin component, a compound having at least a repeating unit expressed by formula (1) is preferable. In formula (1), n represents an integer ≥1, X represents a 1-10C straight-chain or branched alkyl chain, an aromatic or alicyclic cyclic alkyl chain, or an alkyl ester chain, and Y represents a substituent which generates a sulfonic acid residue when specified energy is applied. <P>COPYRIGHT: (C)2004,JPO

Description

（式中、ｎは１以上の整数を表し、Ｘは炭素原子数１〜１０の直鎖もしくは分岐状のアルキル鎖、芳香性もしくは脂環性の環状アルキル鎖、アルキルエステル鎖であり、Ｙは所定のエネルギーの印加を受けてスルホン酸残基を生じる置換基である。）
で表される繰り返し単位を有することを特徴とする。
【００２９】
前記スルホン酸残基を生じさせるために印加される所定のエネルギーとしては、例えば、８０℃以上の加熱処理等でスルホン酸残基を生じさせることができる。このような所定のエネルギーの印加は、剥離処理における加熱とアルカリの協奏作用によりさらに促進される。
【００３０】
前記一般式（１）の置換基Ｙとしては、−ＳＯ_３Ｒ_１もしくは−ＳＯ_３ ⁻Ｒ_２ ^＋（式中、Ｒ_１およびＲ_２は１価の有機基）が好ましい。
【００３１】
前記有機基Ｒ_１としては、炭素原子数１〜１０のアルキル基、あるいはヒドロキシアルキル基のなかから選ばれる１種が好ましい。
【００３２】
また、前記有機基Ｒ_２としては、アルカノールアミン、およびアルキルアミンの中から選ばれる少なくとも１種が好ましい。
【００３３】
さらに、前記所定のエネルギーが印加されることにより末端基が脱離してスルホン酸残基を生じる置換基を少なくとも有する樹脂成分として、前述のいずれかの樹脂成分と、アクリル酸またはメタアクリル酸あるいはそれらの誘導体との共重合体あるいは混合樹脂を用いてもよい。
【００３４】
樹脂成分として、前記共重合体あるいは混合樹脂を用いる場合、その重合比あるいは混合比は、２．３８ｗｔ％ＴＭＡＨ現像液に対する耐性があり、レジスト剥離液にて除去できるという効果を維持できる範囲にあれば、特に限定されない。
【００３５】
さらにまた、前記所定のエネルギーが印加されることにより末端基が脱離してスルホン酸残基を生じる置換基を少なくとも有する樹脂成分として、
前述のいずれかの樹脂成分とアクリル酸またはメタアクリル酸あるいはそれらの誘導体との共重合体あるいは混合樹脂に対して、下記一般式（２）
【化４】

（式中、ｎは１以上の整数を表し、Ｒ_３は水素原子、フッ素原子、水酸基、カルボキシル基、炭素原子数１〜５のヒドロキシアルキル基、炭素原子数１〜５のアルコキシアルキル基の中から選ばれる少なくとも１種であり、Ｚは炭素原子数１〜１０の直鎖もしくは分岐状のアルキル鎖、芳香性もしくは脂環性の環状アルキル鎖、アルキルエステル鎖である。）
で表される繰り返し単位を共重合させた共重合体もしくは前記一般式（２）で表される繰り返し単位を有する樹脂化合物を混合させた混合樹脂からなる樹脂成分を用いてもよい。
【００３６】
前記一般式（２）の誘導体を用いて共重合体を調製し、その共重合体を樹脂成分として下層膜材料を構成すれば、樹脂成分のユニットにアントラセンが含まれることになり、このアントラセンは、特にＫｒＦエキシマレーザを用いたリソグラフィーにおいて吸収特性が高く、好ましい。
【００３７】
本発明の下層膜形成材料に用いる溶媒としては、従来の下層膜形成材料に用いられるものであれば、特に制限することなく用いることができる。
【００３８】
具体的には、例えば、アセトン、メチルエチルケトン、シクロペンタノン、シクロヘキサノン、メチルイソアミルケトン、２−ヘプタノン、１，１，１−トリメチルアセトン等のケトン類；エチレングリコール、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノブチルエーテル、エチレングリコールモノアセテート、エチレングリコールモノメチルエーテルアセテート、エチレングリコールモノエチルエーテルアセテート、ジエチレングリコール、ジエチレングリコールモノアセテート、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノブチルエーテル、プロピレングリコール、プロピレングリコールモノメチルエーテル、ジプロピレングリコールモノメチルエーテル、グリセリン、１，２−ブチレングリコール、１，３−ブチレングリコール、２，３−ブチレングリコール等の多価アルコール類およびその誘導体；ジオキサンのような環状エーテル類；乳酸エチル、酢酸メチル、酢酸エチル、酢酸ブチル、ピルビン酸メチル、ピルビン酸エチル、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等のエステル類；ジメチルスルホキシド等のスルホキシド類；ジメチルスルホン、ジエチルスルホン、ビス（２−ヒドロキシエチル）スルホン、テトラメチレンスルホン等のスルホン類；Ｎ，Ｎ−ジメチルホルムアミド、Ｎ−メチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ−メチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド等のアミド類；Ｎ−メチル−２−ピロリドン、Ｎ−エチル−２−ピロリドン、Ｎ−ヒドロキシメチル−２−ピロリドン、Ｎ−ヒドロキシエチル−２−ピロリドン等のラクタム類；β−プロピオラクトン、γ−ブチロラクトン、γ−バレロラクトン、δ−バレロラクトン、γ−カプロラクトン、ε−カプロラクトン等のラクトン類；１，３−ジメチル−２−イミダゾリジノン、１，３−ジエチル−２−イミダゾリジノン、１，３−ジイソプロピル−２−イミダゾリジノン等のイミダゾリジノン類；等を挙げることができる。これらは１種を用いてもよく、２種以上を混合して用いてもよい。
【００３９】
また、本発明に係る下層膜形成材料には、架橋剤が含まれていてもよく、そのような架橋剤は、本発明に用いる樹脂成分を架橋させることができれば特に限定するものではないが、アミノ基および／またはイミノ基を有する含窒素化合物であって、この含窒素化合物中に存在する全てのアミノ基および／またはイミノ基において、少なくとも２つの水素原子がヒドロキシアルキル基および／またはアルコキシアルキル基で置換された含窒素化合物が好ましい。
【００４０】
前記置換基の数は、含窒素化合物中、２以上、実質的には６以下とされる。
【００４１】
具体的には、例えば、メラミン系化合物、尿素系化合物、グアナミン系化合物、アセトグアナミン系化合物、ベンゾグアナミン系化合物、グリコールウリル系化合物、スクジニルアミド系化合物、エチレン尿素系化合物等において、アミノ基および／またはイミノ基の２つ以上の水素原子が、メチロール基またはアルコキシメチル基あるいはその両方で置換された化合物等を挙げることができる。
【００４２】
これらの含窒素化合物は、例えば、上記メラミン系化合物、尿素系化合物、グアナミン系化合物、アセトグアナミン系化合物、ベンゾグアナミン系化合物、グリコールウリル系化合物、スクシニルアミド系化合物、エチレン尿素系化合物等を、沸騰水中においてホルマリンと反応させてメチロール化することにより、あるいはこれにさらに低級アルコール、具体的にはメタノール、エタノール、ｎ−プロパノール、イソプロパノール、ｎ−ブタノール、イソブタノール等と反応させてアルコキシル化することにより、得ることができる。
【００４３】
また、前記架橋剤として、前記ヒドロキシアルキル基および／またはアルコキシアルキル基と、モノヒドロキシモノカルボン酸との縮合反応物を用いれば、レジストパターン下部の形状改善（フッティングの防止）効果が得られるので、好ましい。
【００４４】
前記モノヒドロキシモノカルボン酸としては、水酸基とカルボキシル基が、同一の炭素原子、または隣接する二つの炭素原子のそれぞれに結合しているものが、フッティング防止の点から好ましい。
【００４５】
また、モノヒドロキシモノカルボン酸との縮合反応物を用いる場合は、縮合前の架橋剤１モルに対して、０．０１〜６モル、好ましくは０．１〜５モルの割合で、モノヒドロキシカルボン酸を縮合反応して得られる反応物を用いることが、フッティング防止効果を得る点から好ましい。この縮合反応は慣用の方法によって行うことができる。
【００４６】
なお、本発明において、前記架橋剤は、１種で用いてもよいし、２種以上を混合して用いてもよい。
【００４７】
さらに、本発明に係る下層膜形成材料には、酸性化合物、界面活性剤を、必要に応じて、添加可能である。
【００４８】
前記酸性化合物の添加効果は、フッティングの防止特性が向上する点にある。このような酸性化合物としては、硫黄含有酸残基を持つ無機酸、有機酸またはそれらのエステル等や、活性光線により酸を発生する化合物（酸発生剤、例えばオニウム塩）等を挙げることができる。この酸性化合物の配合量は、全固形分１００質量部に対して０．０１〜３０質量部、好ましくは０．１〜２０質量部である。下限値未満では添加効果が得られず、上限値を超えるとレジストパターンの下部にくい込みを生じるおそれがでてくる。
【００４９】
前記界面活性剤の添加効果は、下層膜材料の塗布性の向上である。このような界面活性剤としては、例えば、サーフロンＳＣ−１０３、ＳＲ−１００（以上、旭硝子株式会社製）、ＥＦ−３５１（東北肥料株式会社製）、フロラードＦｃ−４３１、フロラードＦｃ−１３５、フロラードＦｃ−９８、フロラードＦｃ−４３０、フロラードＦｃ−１７６（以上、住友３Ｍ株式会社製）、メガファックＲ−０８（大日本インキ株式会社製）等のフッ素系界面活性剤、を挙げることができる。
【００５０】
この界面活性剤の添加量は、好ましくは、下層膜材料中の全固形分の２００ｐｐｍ未満の範囲で設定する。
【００５１】
次に、本発明に係る配線形成方法を、図１（ａ）〜（ｄ）および図２（ｅ）〜（ｈ）を参照しつつ、さらに詳しく説明する。本発明の配線形成方法では、まず、
図１（ａ）に示すように、シリコンウェハなどの基板１ａ上に誘電体層１ｂが積層されてなる半導体基板１上に、前記本発明の多層レジスト下層膜形成材料を用いて、厚膜のレジスト下層膜２を形成する（下層膜形成工程（ａ））。
次に、図１（ｂ）に示すように、前記下層膜２上にスピンオングラス材料を用いて中間層膜３を形成する（中間層膜形成工程（ｂ））。
次に、図１（ｃ）に示すように、前記中間層膜３上にホトレジスト材料からなるレジスト上層膜４を形成し、このレジスト上層膜４に露光および現像処理を施して、所定のホトレジストパターン５を形成する（上層レジストパターン形成工程（ｃ））。
次に、図１（ｄ）に示すように、前記上層レジストパターン５をマスクとして前記中間層膜３をドライエッチングにより加工して、中間層パターン６を形成する（中間層パターン形成工程（ｄ））。
次に、図２（ｅ）に示すように、前記中間層パターン６をマスクとして前記下層膜２をドライエッチングにより加工して、下層パターン７を形成する（下層パターン形成工程（ｅ））。
次に、図２（ｆ）に示すように、前記下層パターン７をマスクとして、前記基板１の誘電体層１ｂをエッチングして所定の配線パターン８を形成する（配線パターン形成工程（ｆ））。
その後、図２（ｇ）に示すように、前記配線パターン６の形成後の基板１上に残留する前記下層レジストパターン７をホトレジスト剥離液により除去する（レジストパターン除去工程（ｇ））。
最後に、図２（ｈ）に示すように、前記配線パターン８に、導体材料を気相法により堆積させるか、あるいは導体材料を埋め込むことによって、配線層９を形成する（配線層形成工程（ｈ））。
【００５２】
本発明の配線形成方法は、これら工程（ａ）〜（ｇ）を少なくとも含むことを特徴とするものである。なお、この方法の説明では、もっとも簡単な配線構造を想定したが、多層の配線層からなり、各上下の配線層がビア配線により電気的に接続されている構造の多層配線構造にももちろん適用できる。本願発明方法の構成は、必要最小限の工程を示したものである。さらに、この方法は、いわゆるダマシンプロセスを想定したものであるが、多層構造を得る場合には、必然的にデュアルダマシンプロセスが採用されることになる。このデュアルダマシンプロセスは、トレンチと呼称される配線溝とビアホールとを連続して形成することが特徴であり、形成順序は、トレンチを先に形成し、続いてビアホールを形成する場合と、逆にビアホールを先に形成し、続いてトレンチを形成する場合とがある。本発明は、そのどちらにも適用可能である。
【００５３】
前記構成の配線形成方法において、前記下層パターン除去工程（ｇ）に用いられる前記ホトレジスト剥離液は、少なくとも水溶性アミン、および第４級アンモニウム水酸化物の中から選ばれる少なくとも１種を含有することが好ましい。なかでも好ましく用いられるのは、第４級アンモニウム水酸化物を含有するホトレジスト剥離液である。
【００５４】
前記水溶性アミンとしては、アルカノールアミン、およびアルキルアミンから選ばれる少なくとも１種であることが好ましい。
【００５５】
このようなアミン系剥離液を含有する系の剥離剤には、さらに非アミン系水溶性有機溶剤、水、防食剤、界面活性剤等が配合されてもよい。
【００５６】
前記非アミン系水溶性有機溶剤としては、例えば、ジメチルスルホキシド等のスルホキシド類；ジメチルスルホン、ジエチルスルホン、ビス（２−ヒドロキシエチル）スルホン、テトラメチレンスルホン等のスルホン類；Ｎ，Ｎ−ジメチルホルムアミド、Ｎ−メチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ−メチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド等のアミド類；Ｎ−メチル−２−ピロリドン、Ｎ−エチル−２−ピロリドン、Ｎ−ヒドロキシメチル−２−ピロリドン、Ｎ−ヒドロキシエチル−２−ピロリドン等のラクタム類；β−プロピオラクトン、γ−ブチロラクトン、γ−バレロラクトン、δ−バレロラクトン、γ−カプロラクトン、ε−カプロラクトン等のラクトン類；１，３−ジメチル−２−イミダゾリジノン、１，３−ジエチル−２−イミダゾリジノン、１，３−ジイソプロピル−２−イミダゾリジノン等のイミダゾリジノン類；エチレングリコール、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノブチルエーテル、エチレングリコールモノアセテート、エチレングリコールモノメチルエーテルアセテート、エチレングリコールモノエチルエーテルアセテート、ジエチレングリコール、ジエチレングリコールモノアセテート、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノブチルエーテル、プロピレングリコール、プロピレングリコールモノメチルエーテル、ジプロピレングリコールモノメチルエーテル、グリセリン、１，２−ブチレングリコール、１，３−ブチレングリコール、２，３−ブチレングリコール等の多価アルコール類およびその誘導体を挙げることができる。これらは１種を用いてもよく、２種以上を混合して用いてもよい。
【００５７】
また、本発明方法において、前記下層膜の剥離処理に先立って、オゾン水および／または過酸化水素水に接触させる工程を設けても良い。オゾン水は純水中にオゾンガスをバブリング等の手段により溶解させたものを用いるのが好ましい。また、オゾン含有濃度は１ｐｐｍ以上から飽和濃度の間で用いればよく、過酸化水素水は濃度０．１〜６０質量％の水溶液で用いればよい。接触の方法としては、浸漬法、パドル法、シャワー法等が挙げられる。こうした前処理を行うことにより、レジスト下層膜およびレジスト上層膜の除去性能を向上させることができる。
【００５８】
本発明方法において、レジスト上層膜を形成するためのホトレジスト組成物としては、ＫｒＦ、ＡｒＦ、Ｆ_２エキシマレーザ、あるいは電子線用に慣用されるホトレジスト材料を、常法により用いることができる。
【００５９】
また、本発明方法において、露光、現像処理は、通常のリソグラフィーで常用のプロセスを用いることができる。
【００６０】
前記中間層を形成するためのシリコン酸化膜材料としては、各種ケイ素含有ポリマーを用いることができる。中でもスピンオングラス材料を好適に用いることができる。このようなスピンオングラス材料としては、
（Ａ） Ｓｉ（ＯＲ^１）_ａ（ＯＲ^２）_ｂ（ＯＲ^３）_ｃ（ＯＲ^４）_ｄ
（式中、Ｒ^１，Ｒ^２，Ｒ^３，およびＲ^４は、それぞれ独立に炭素数１〜４のアルキル基またはフェニル基、ａ，ｂ，ｃ，およびｄは、０≦ａ≦４，０≦ｂ≦４，０≦ｃ≦４、０≦ｄ≦４であって、かつａ＋ｂ＋ｃ＋ｄ＝４の条件を満たす整数である。）で表される化合物、
（Ｂ） Ｒ^５Ｓｉ（ＯＲ^６）_ｅ（ＯＲ^７）_ｆ（ＯＲ^８）_ｇ
（式中、Ｒ５は水素原子あるいは炭素数１〜４のアルキル基、Ｒ^６，Ｒ^７，およびＲ^８は、それぞれ炭素数１〜３のアルキル基またはフェニル基、ｅ，ｆ，およびｇは、０≦ｅ≦３，０≦ｆ≦３，０≦ｇ≦３であって、かつｅ＋ｆ＋ｇ＝３の条件を満たす整数である。）で表される化合物、および
（Ｃ） Ｒ^９Ｒ^１０Ｓｉ（ＯＲ^１１）_ｈ（ＯＲ^１２）_ｉ
（式中、Ｒ^９およびＲ^１０は水素原子あるいは炭素数１〜４のアルキル基、Ｒ^１１およびＲ^１２は、それぞれ炭素数１〜３のアルキル基またはフェニル基、ｈおよびｉは、０≦ｈ≦２，０≦ｉ≦２であって、かつｈ＋ｉ＝２の条件を満たす整数である。）で表される化合物から選ばれる少なくとも１種の化合物を水の存在下で酸の作用により加水分解させたものである。
【００６１】
前記（Ａ）の化合物としては、例えば、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシラン、テトラブトキシシラン、テトラフェニルオキシシラン、トリメトキシモノエトキシシラン、ジメトキシジエトキシシラン、トリエトキシモノメトキシシラン、トリメトキシモノプロポキシシラン、モノメトキシトリブトキシシラン、モノメトキシトリフェニルオキシシラン、ジメトキシジプロポキシシラン、トリプロポキシモノメトキシシラン、トリメトキシモノブトキシシラン、ジメトキシジブトキシシラン、トリエトキシモノプロポキシシラン、ジエトキシジプロポキシシラン、トリブトキシモノプロポキシシラン、ジメトキシモノエトキシモノブトキシシラン、ジエトキシモノメトキシモノブトキシシラン、ジエトキシモノプロポキシモノブトキシシラン、ジプロポキシモノメトキシモノエトキシシラン、ジプロポキシモノメトキシモノブトキシシラン、ジプロポキシモノエトキシモノブトキシシラン、ジブトキシモノメトキシモノエトキシシラン、ジブトキシモノエトキシモノプロポキシシラン、モノメトキシモノエトキシプロポキシモノブトキシシランなどのテトラアルコキシシランまたはそれらのオリゴマーが挙げられ、なかでもテトラメトキシシラン、テトラエトキシシランまたはそれらのオリゴマーが好ましい。
【００６２】
また、前記（Ｂ）の化合物としては、例えば、トリメトキシシラン、トリエトキシシラン、トリブロポキシシラン、トリフェニルオキシシラン、ジメトキシモノエトキシシラン、ジエトキシモノメトキシシラン、ジプロポキシモノメトキシシラン、ジプロポキシモノエトキシシラン、ジフェニルオキシルモノメトキシシラン、ジフェニルオキシモノエトキシシラン、ジフェニルオキシモノプロポキシシラン、メトキシエトキシプロポキシシラン、モノプロポキシジメトキシシラン、モノプロポキシジエトキシシラン、モノブトキシジメトキシシラン、モノフェニルオキシジエトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、メチルトリプロポキシシラン、エチルトリメトキシシラン、エチルトリプロポキシシラン、エチルトリフェニルオキシシラン、プロピルトリメトキシシラン、プロピルトリエトキシシラン、プロピルトリフェニルオキシシラン、ブチルトリメトキシシラン、ブチルトリエトキシシラン、ブチルトリプロポキシシラン、ブチルトリフェニルオキシシラン、メチルモノメトキシジエトキシシラン、エチルモノメトキシジエトキシシラン、プロピルモノメトキシジエトキシシラン、ブチルモノメトキシジエトキシシラン、メチルモノメトキシジプロポキシシラン、メチルモノメトキシジフェニルオキシシラン、エチルモノメトキシジプロポキシシラン、エチルモノメトキシジフェニルオキシシラン、プロピルモノメトキシジプロポキシシラン、プロピルモノメトキシジフェニルオキシシラン、ブチルモノメトキシジプロポキシシラン、ブチルモノメトキシジフェニルオキシシラン、メチルメトキシエトキシプロポキシシラン、プロピルメトキシエトキシプロポキシシラン、ブチルメトキシエトキシプロポキシシラン、メチルモノメトキシモノエトキシモノブトキシシラン、エチルモノメトキシモノエトキシモノブトキシシラン、プロピルモノメトキシモノエトキシモノブトキシシラン、ブチルモノメトキシモノエトキシモノブトキシシランなどが挙げられ、なかでもトリメトキシシラン、トリエトキシシランが好ましい。
【００６３】
さらに、前記（Ｃ）の化合物としては、例えば、ジメトキシシラン、ジエトキシシラン、ジプロポキシシラン、ジフェニルオキシシラン、メトキシエトキシシラン、メトキシプロポキシシラン、メトキシフェニルオキシシラン、エトキシプロポキシシラン、エトキシフェニルオキシシラン、メチルジメトキシシラン、メチルメトキシエトキシシラン、メチルジエトキシシラン、メチルメトキシプロポキシシラン、メチルメトキシフェニルオキシシラン、エチルジプロポキシシラン、エチルメトキシプロポキシシラン、エチルジフェニルオキシシラン、プロピルジメトキシシラン、プロピルメトキシエトキシシラン、プロピルエトキシプロポキシシラン、プロピルジエトキシシラン、プロピルジフェニルオキシシラン、ブチルジメトキシシラン、ブチルメトキシエトキシシラン、ブチルジエトキシシラン、ブチルエトキシプロポキシシラン、ブチルジプロポキシシラン、ブチルメチルフェニルオキシシラン、ジメチルジメトキシシラン、ジメチルメトキシエトキシシラン、ジメチルジエトキシシラン、ジメチルジフェニルオキシシラン、ジメチルエトキシプロポキシシラン、ジメチルジプロポキシシラン、ジエチルジメトキシシラン、ジエチルメトキシプロポキシシラン、ジエチルジエトキシプロポキシシラン、ジプロピルジメトキシシラン、ジプロピルジエトキシシラン、ジプロピルジフェニルオキシシラン、ジブチルジメトキシシラン、ジブチルジエトキシシラン、ジブチルジプロポキシシラン、ジブチルメトキシフェニルオキシシラン、メチルエチルジメトキシシラン、メチルエチルジエトキシシラン、メチルエチルジプロポキシシラン、メチルエチルジフェニルオキシシラン、メチルプロピルジメトキシシラン、メチルプロピルジエトキシシラン、メチルブチルジメトキシシラン、メチルブチルジエトキシシラン、メチルブチルジプロポキシシラン、メチルエチルエトキシプロポキシシラン、エチルプロピルジメトキシシラン、エチルプロピルメトキシエトキシシラン、ジプロピルジメトキシシラン、ジプロピルメトキシエトキシシラン、プロピルブチルジメトキシシラン、プロピルブチルジエトキシシラン、ジブチルメトキシプロポキシシラン、ブチルエトキシプロポキシシランなどが挙げられ、なかでもジメトキシシラン、ジエトキシシラン、メチルジメトキシシランが好ましい。
【００６４】
中間層であるスピンオングラス材料をドライエッチングするエッチングガスとしては、フルオロカーボン系ガスを主成分とするガスが用いられる。
【００６５】
また、本発明の下層膜材料をドライエッチングするエッチングガスとしては、酸素系ガスを主成分とするガスが用いられる。
【００６６】
【実施例】
以下、本発明の実施例を説明する。以下の実施例は、本発明を好適に説明する例示にすぎず、本発明をなんら限定するものではない。
【００６７】
（実施例１〜４）
下層膜形成材料として、次の（Ａ）、（Ｂ）、（Ｃ）、および（Ｄ）の樹脂組成物を調製した。
【００６８】
（Ａ） ｐ−スチレンスルホン酸エチルからなる樹脂成分を、γ−ブチロラクトン／乳酸エチル（２：８）からなる溶媒に溶解し、固形分濃度を６ｗｔ％に調整した樹脂組成物。
【００６９】
（Ｂ） ｐ−スチレンスルホン酸エチル：ヒドロキシエチルアクリレート（＝５：５）からなる樹脂成分と、該樹脂成分量の２０ｗｔ％相当量のサイメル１１７２（三井サイアナミッド社製テトラメチロールグリコールウリル）とを、乳酸エチルからなる溶媒に溶解し、固形分濃度を６ｗｔ％に調整した樹脂組成物。
【００７０】
（Ｃ） ｐ−スチレンスルホン酸エチル：９−ヒドロキシアントラセニルアクリレート（＝５：５）からなる樹脂成分を、γ−ブチロラクトン／乳酸エチル（２：８）からなる溶媒に溶解し、固形分濃度を６ｗｔ％に調整した樹脂組成物。
【００７１】
（Ｄ） ｐ−スチレンスルホン酸エチル：ヒドロキシエチルアクリレート：９−ヒドロキシアントラセニルアクリレート（＝４：３：３）からなる樹脂成分と、該樹脂の２０ｗｔ％相当量のサイメル１１７２（三井サイアナミッド株式会社製テトラメチロールグリコールウリル）と、前記２種の固形分量の１０００ｐｐｍ相当量のメガファックＲ０８（大日本インキ株式会社製フッ素系界面活性剤）とを、乳酸エチルからなる溶媒に溶解し、固形分濃度を６ｗｔ％に調整した樹脂組成物。
【００７２】
一方、図３（ａ）に示すように、表面に銅配線層１１を形成した基板１２上に、第１層としてＳｉＮ膜からなる第１バリア層１３を形成し、第２層として低誘電体材料（東京応化工業株式会社製：商品名ＯＣＤ−Ｔ１２）からなる第１低誘電体層１４を形成し、第３層としてＳｉＮ膜からなる第２バリア層１５を形成し、さらに第４層として低誘電体材料（東京応化工業株式会社製：商品名ＯＣＤ−Ｔ１２）からなる第２低誘電体層１６を形成した。
【００７３】
次に、図３（ｂ）に示すように、前記第２低誘電体層１６の上にホトレジスト層１７を形成し、このホトレジスト層１７をリソグラフィー法により加工してレジストパターン１８を得た。得られたレジストパターン１８をマスクとして、前記第１〜４層を貫通して前記銅配線層１１に連通するビアホール１９を形成した。ビアホール１９の形成後、レジストパターン１８を除去した。
【００７４】
図３（ｃ）に示すように、前記ビアホール１９を形成し、レジストパターン１８を除去した後の前記第２低誘電体層１６の上に、前述の（Ａ）（Ｂ）（Ｃ）（Ｄ）の樹脂組成物を、それぞれ、塗布するとともに、前記ビアホールを埋め込み、その後、２００℃にて９０秒間加熱処理し、前記第２低誘電体層の上に膜厚３０００Åの下層膜２０を形成した。この下層膜２０の上に、スピンオングラス材料を主成分とする樹脂組成物を塗布して膜厚１５０Åの中間層膜２１を形成した。さらに、この中間層膜２１の上に、ホトレジスト組成物（東京応化工業株式会社製：商品名ＴＡｒＦ−Ｐ６０７１）を塗布し、１２０℃で９０秒間加熱処理して膜厚４００ｎｍの上層膜２２を形成した。次に、前記上層膜２２を露光し、露光後加熱（１２０℃、９０秒間）を施し、現像処理して、トレンチ形成用の上層レジストパターン２３を形成した。
【００７５】
前記上層レジストパターン２３をマスクとして、フルオロカーボン系エッチングガスを用いて、前記中間層膜２１を加工して中間層膜パターンを得た。続いて、前記中間層膜パターンをマスクとして、酸素系エッチングガスを用いて、図３（ｄ）に示すように、前記下層膜２０を加工して下層膜パターン２４を形成し、前記中間層レジストパターンを除去することによって、トレンチを形成するための最終レジストパターンを得た。この時点で、基板表面を走査型電子顕微鏡にて観察したが、ポイゾニングの悪影響によるレジストパターンのパターン不良はなく、トレンチを構成する低誘電体層のダメージも見られなかった。
【００７６】
通常の配線層形成プロセスでは、引き続いて、前記最終レジストパターン（下層レジストパターン）をマスクとして、前記第２の低誘電体層１６のエッチングを行って、図３（ｅ）に示すように、深さが前記第２のバリア層１５に至る所定のパターンのトレンチ２５を形成する。その後、銅を前記ビアホール１９とトレンチ２５とに埋め込むことによって、多層配線構造を形成する。
【００７７】
本実施例では、前記最終レジストパターン２４を得たところで、パターニングに不良が発生していることが確認されたという状況を想定して、リワークのためのレジストパターンの除去プロセスを以下のように実行した。
【００７８】
１００℃に調整したジメチルスルホキシドとモノエタノールアミンの混合溶剤（混合比＝７：３）からなるホトレジスト剥離液中に、前記下層レジストパターン２４を有する基板を２０分間浸漬し、レジストパターンの剥離処理を行った。剥離処理後、基板表面を走査型顕微鏡にて観察したが、下層膜材料として前記樹脂組成物（Ａ）から（Ｄ）のいずれを用いた場合でも、レジストパターンの残留物は存在せず、レジストパターンの剥離除去が確実に行われていることを確認できた。また、レジストパターン剥離処理による低誘電体層１６へのダメージも観察されなかった。
【００７９】
（実施例５）
前記（Ｃ）の樹脂組成物において、その樹脂成分量の３ｗｔ％相当量の「光酸発生剤であるＴＰＳ−１０９（緑化学株式会社製）」を追加配合して、新たな樹脂組成物（Ｃ２）を調製した。この樹脂組成物（Ｃ２）を用いた以外は前記実施例１と全く同様の手法にてレジストパターンを形成した。その結果、寸法制御性に優れた矩形のレジストパターンを得ることができ、低誘電体層からのポイゾニングの影響が本発明の下層膜材料により抑止できていることが確認された。また、レジストパターン剥離処理を行った後に低誘電体層表面を走査型顕微鏡により観察したが、剥離除去処理後の基板表面には、レジストパターンの残留物は見られず、除去が十分に行われていることが確認された。さらに、低誘電体層へのダメージもなかった。
【００８０】
（比較例１）
ヘキサメトキシメチル化メラミンをプロピレングリコールモノメチルエーテルアセテートに溶解してなる樹脂組成物から、下層膜材料を構成し、下層パターンの除去をＯ_２プラズマアッシング処理により行ったこと以外は、前記実施例と同様の操作にて、レジストパターンの形成、およびその剥離除去を行った。その結果、トレンチ形成用ホトレジストパターンにポイゾニングが発生し、パターン像が形成できない部分が発生した。さらに、パターンのＯ_２プラズマアッシングによる剥離処理により低誘電体層に深刻なダメージが発生していた。
【００８１】
（比較例２）
前記比較例１において、下層パターンの除去を、前記実施例で用いたホトレジスト剥離液により行った。結果として、パターンの除去はできなかった。
【００８２】
【発明の効果】
以上説明したように、本発明の多層レジストプロセス用下層膜形成材料は、所定のエネルギーが印加されることにより末端基が脱離してスルホン酸残基を生じる置換基を少なくとも有する樹脂成分と、溶媒とを含有していることを特徴とするものである。かかる構成において、前記樹脂成分は、少なくとも下記一般式（１）
【化５】

（式中、ｎは１以上の整数を表し、Ｘは炭素原子数１〜１０の直鎖もしくは分岐状のアルキル鎖、芳香性もしくは脂環性の環状アルキル鎖、アルキルエステル鎖であり、Ｙは所定のエネルギーの印加を受けてスルホン酸残基を生じる置換基である。）
で表される繰り返し単位を有するものが好ましい。
【００８３】
係る構成によって、本発明は、以下の効果を得ることができる。
（１） 本発明の下層膜は、ホトレジスト剥離液により除去可能であるため、誘電率（ｋ）が３．０以下の低誘電体材料のようなＯ_２アッシングプラズマ耐性が低い材料を積層した半導体基板におけるリソグラフィープロセスに用いる下層膜材料として、好適である。
（２） また、リソグラフィーの不良により基板を回収する必要が生じた場合、基板にダメージを与えることの少ないウェット処理により下層膜を容易に除去できるので、基板回収のリワーク処理を確実かつ容易に行うことができる。その結果、Ｏ_２プラズマアッシングを用いた場合に生じるような、シリコン含有レジストの変質による難溶化、下層膜の難溶化等により基板再生処理が困難になる事態を、回避することができる。
（３） さらに、多層レジストの下層膜と、デュアルダマシンプロセスにおける埋込材とを兼用させれば、低誘電体層にデュアルダマシン構造を形成する場合に発生しやすいポイゾニング現象によるレジストパターンの劣化を防止ないしは抑止することができる。
【図面の簡単な説明】
【図１】本発明の多層レジストプロセス用下層膜形成材料を用いた配線形成方法を説明するためのもので、（ａ）〜（ｄ）はリソグラフィーを用いた配線形成の前半の工程図である。
【図２】本発明の多層レジストプロセス用下層膜形成材料を用いた配線形成方法を説明するためのもので、（ｅ）〜（ｆ）は、図１（ｄ）に続く、リソグラフィーを用いた配線形成の後半の工程図である。
【図３】本発明の多層レジストプロセス用下層膜形成材料を用いた配線形成方法をデュアルダマシン構造形成に適用した実施例を説明するためのもので、（ａ）〜（ｅ）はデュアルダマシン構造が形成されるまでの工程図である。
【符号の説明】
１ 半導体基板
１ａ 基板
１ｂ 誘電体層
２ 下層膜
３ 中間層膜
４ レジスト上層膜
５ 上層レジストパターン
６ 中間層パターン
７ 下層パターン
８ 配線パターン
９ 配線層
１１ 配線層
１２ 基板
１３ 第１のエッチングストッパ層
１４ 第１の低誘電体層
１５ 第２のエッチングストッパ層
１６ 第２の低誘電体層
１７ ホトレジスト層
１８ レジストパターン
１９ ビアホール
２０ 下層膜
２１ 中間層膜
２２ レジスト上層膜
２３ 上層レジストパターン
２４ 下層パターン
２５ トレンチ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is characterized in that a photoresist layer used for lithography for forming a wiring has a multilayer structure composed of at least a lower layer film composed of an organic film, an intermediate layer film, and a photoresist upper layer film, thereby improving the resist pattern accuracy. The present invention relates to a lower layer film forming material suitable for a multilayer resist process and a wiring forming method using the lower layer film forming material. More specifically, the present invention not only has excellent properties as a lower layer film as a final pattern in patterning a multilayer resist, but also is easy to remove after use, and has no adverse effect on the substrate due to the removal treatment. And a wiring forming method using the same.
[0002]
[Prior art]
As is well known, a semiconductor substrate is formed by laminating a dielectric layer (insulator layer) on a substrate such as a silicon wafer, and a conductive layer (wiring) patterned in the dielectric layer of the semiconductor substrate. The formation of the layer) forms a semiconductor wiring structure.
[0003]
There are roughly two methods for forming the wiring layer. In the first method, a conductor layer is uniformly formed on the dielectric layer, a photoresist is formed on the conductor layer, and the photoresist is irradiated (exposed) with pattern light and developed to form a resist pattern. Using the resist pattern as a mask, the conductor layer is patterned by etching to form a wiring layer, and after removing the resist pattern, a dielectric layer is further laminated to form a dielectric layer. Configure the wiring layer.
[0004]
In a second method, a photoresist pattern is formed on the dielectric layer, a wiring groove (trench) is formed in the dielectric layer by etching using the resist pattern as a mask, and the resist pattern is removed. After that, a conductor material is buried in the wiring groove, and a dielectric layer is laminated thereon, whereby a semiconductor wiring structure is formed.
[0005]
When the wiring structure is multilayered, a plurality of wiring layers are laminated by repeating the wiring layer forming step in each of the above methods. However, a via wiring forming step is required between each wiring layer forming step. It becomes. In the via wiring forming step, a via hole is formed in a dielectric layer serving as an interlayer insulating layer between the lower wiring layer and the upper wiring layer, and a conductor material is deposited or embedded in the via hole by a vapor phase method. This is a step of forming a via wiring for electrically connecting the lower wiring layer and the upper wiring layer.
[0006]
In a device having the above-described wiring structure, high integration is a constant problem, and finer wiring is required. For miniaturization of wiring, it is necessary to improve the pattern resolution of a photoresist for lithography and the pattern resolution of a wiring layer or a wiring groove by etching using a resist pattern obtained by exposure as a mask. . The smaller the thickness of the resist layer, the higher the accuracy of pattern transfer to the resist using the exposure apparatus and the wiring pattern mask. On the other hand, if the thickness of the resist layer is small, it becomes difficult to maintain the resist resistance of the resist layer in the etching process of the lower layer using the resist pattern as a mask, which adversely affects the resolution of the wiring layer or the wiring groove by the etching. Easy. In order to increase the resist resistance, a thicker film is preferable. As described above, in order to increase the lithography accuracy using the photoresist, there is a trade-off between setting the thickness of the photoresist. As a technique for solving such a problem and improving the lithography accuracy using a photoresist, a wiring forming method using a multilayer resist has been provided (for example, Patent Document 1).
[0007]
This technique, namely the multi-layer resist process, uses a multi-layer resist structure instead of a single-layer resist, and (1) thins the topmost photoresist film to which a pattern is first transferred from a mask to reduce the resolution and depth of focus in lithography. (2) A multi-layered anti-reflection film or the like having a small thin film interference effect and high resistance to etching under the uppermost layer film, and having a high pattern transfer accuracy and excellent dry etching resistance This is a technique for obtaining patterns. In this technique, first, a composite antireflection film is formed on a substrate. The composite anti-reflection film is, for example, a multilayer film including a carbon film and a silicon oxide film, and a silicon nitride barrier layer provided between them, if necessary. On this multilayer film, a thin photoresist upper layer film is formed. After that, the wiring pattern is transferred to the photoresist upper layer film by lithography to form an upper layer resist pattern. Next, using the obtained upper resist pattern as a mask, the silicon oxide film as the intermediate layer is etched to transfer the pattern. Subsequently, using the upper resist pattern and the intermediate layer pattern as a mask, the lower layer carbon film is etched to transfer a wiring pattern. Finally, by removing the upper resist pattern and the intermediate layer pattern, a carbon film (lower film) pattern having good dry etching resistance and high pattern transfer accuracy can be obtained. The substrate is etched according to the pattern using the carbon film pattern as the lower layer film pattern as a mask.
[0008]
By the way, in the multilayer resist, the pattern of the lower layer film (carbon film) that remains last must be removed by some means when the patterning of the lower conductive layer or the dielectric layer by etching is completed. In Patent Document 1, O₂Removed by plasma ashing.
[0009]
As is well known, in a semiconductor wiring structure, a dielectric layer covering a wiring layer and electrically isolating it from other wiring layers does not affect the electrical characteristics of the wiring layer. It is necessary that the dielectric constant be as low as possible. Specifically, the degree of the low dielectric constant of the dielectric material is that the dielectric constant k is set to 3.0 or less.NeedHave been. However, such a low dielectric constant material is not₂Low resistance to plasma ashing, O₂Exposure to plasma readily degrades the surface and increases the dielectric constant.
[0010]
When a wiring pattern is formed by forming a resist pattern comprising the above-described conventional multilayer resist on a semiconductor substrate using such a low dielectric layer, an O layer used to remove an underlayer film on the substrate is used.₂Deterioration in which the dielectric layer is eroded or its dielectric constant is increased by plasma ashing is likely to occur, and as a result, there is a problem that the electrical characteristics of the wiring layer are adversely affected.
[0011]
In the manufacture of a semiconductor wiring structure, as described above, in order to form a wiring layer on a semiconductor by etching or to form a wiring groove for a buried wiring layer, lithographic patterning of a photoresist or an underlying film is performed. Done. The control factors of this lithography process include controlling the current value and voltage value in the stepper that generates the exposure light, adjusting the focal position of the lens, the accuracy of the photomask, its mounting position accuracy, and the coating characteristics of the photoresist composition. There are many factors such as curing characteristics and curing characteristics, and these control factors may fluctuate for some reason, resulting in poor patterning and the need to repeat the lithography process. In such a case, discarding the semiconductor substrate and using a new semiconductor substrate is a waste of resources and has an adverse effect on the environment. Therefore, in such a manufacturing process, when it is determined that insufficient lithography has been performed, it is necessary to remove the resist remaining on the substrate and recover the semiconductor substrate. Such a process of removing a defective resist in the process of regenerating and collecting a semiconductor substrate is called a rework process, and is an important process when considering the economics of manufacturing a semiconductor wiring structure. Considering the conventional lower film from the viewpoint of such a rework process, the conventional lower film is₂Since plasma ashing must be used, there is a problem that the characteristics of the semiconductor substrate after the rework process are easily deteriorated, which is not appropriate.
[0012]
Further, as described above, a phenomenon called poisoning, which often occurs when a low dielectric layer is used as an interlayer insulating layer supporting a wiring layer, has recently become a problem in a resist pattern forming process. There is a need for a solution.
[0013]
The above-described poisoning phenomenon is likely to occur when a low dielectric layer is used as an interlayer insulating layer, and cannot be suppressed by the conventional lower layer material. Therefore, in the process of forming a wiring structure using a low dielectric layer, it is presently desired to develop a lower film material capable of suppressing the poisoning phenomenon while maintaining the ease of removal after use. .
[0014]
By the way, a technique in which a photoresist layer has a substantially multilayer (two-layer) structure is known, apart from the technique using the multilayer resist, a technique in which an underlayer film for preventing reflection of exposure light is provided below the resist layer. Have been. The lower layer film is made of a resin composition having a high absorption property of the exposure light, and absorbs the patterning light of the upper layer resist to prevent the light from reaching the substrate surface, so that no reflected light of the exposure light is generated. Play a role. If this anti-reflective coating is O₂If the removal can be performed without using plasma ashing and the adverse effect on the resist film due to poisoning can be suppressed, the above-described problem in the wiring forming method using the multilayer resist can be solved.
[0015]
Conventionally, various materials have been proposed as the material of the antireflection film. For example, a resin composition containing a polymer having an iminosulfonate group and a solvent has been proposed (Patent Document 2).
[0016]
Further, a light-absorbing polymer containing a polymer having a hydroxystyrene unit having a specific substituent including a sulfonic acid ester has been developed (Patent Document 3), and the light-absorbing polymer and the solvent are contained. An anti-reflection film forming material has been proposed (Patent Document 4).
[0017]
The antireflection coating material disclosed in Patent Document 2 uses a polymer having an iminosulfonate group as a resin component, and this resin component is insoluble in a stripping solution for a photoresist. Therefore, according to the technique disclosed in Patent Document 2, after removing the upper photoresist pattern with a stripping solution, the remaining lower film is removed with O 2.₂It has been removed by plasma ashing.
[0018]
In addition, the resin components disclosed in Patent Documents 3 and 4 are also insoluble in a photoresist stripping solution, and after removing the photoresist pattern with the stripping solution, the remaining lower layer film is removed.₂Removed by plasma ashing.
[0019]
Therefore, even if the conventional antireflection film is diverted to the lower layer film of the multilayer resist, the problem associated with the removal of the lower layer film cannot be solved.
[0020]
[Patent Document 1]
JP-A-10-92740
[Patent Document 2]
JP-A-10-319601
[Patent Document 3]
JP 2000-512336 A
[Patent Document 4]
JP 2000-512402 A
[0021]
[Problems to be solved by the invention]
The present invention has been made in view of the problems in the conventional lower layer film material of the multilayer resist, and an object of the present invention is to have excellent resistance to a photoresist developer, good patterning characteristics, and resistance to an alkaline compound. Provided is a multilayer resist underlayer film material that can suppress the adverse effect on the resist pattern due to poisoning, can further remove after use with a photoresist stripping solution, and can easily rework the substrate. It is in. It is still another object of the present invention to provide a wiring forming method using a multilayer resist using the above-mentioned lower layer film material.
[0022]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned conventional problems, and as a result, when a predetermined energy is applied, a terminal group is eliminated to form a substituent that generates a sulfonic acid residue. It has been found that if the underlayer film material is constituted by containing at least the resin as a resin component, a good action and effect can be obtained that can solve the conventional problems.
[0023]
That is, if the lower layer film is formed by applying predetermined energy using the lower layer film material as described above, the terminal group of the component resin of the formed lower layer film is sulfonic acid group, and this sulfonic acid When the group becomes a terminal group, the lower layer film becomes compatible with a water-soluble amine or a quaternary ammonium hydroxide. Since the solution containing these water-soluble amines and quaternary ammonium hydroxides can be used as a resist stripping solution, the underlayer film can be easily formed without invading the low dielectric layer by the resist stripping solution. Can be peeled off. In addition, this lower layer film can suppress pattern deterioration of the resist pattern due to the poisoning phenomenon.
[0024]
As described above, the present inventors have determined that “a lower layer film material containing, as a resin component, a resin having at least a substituent whose terminal group is eliminated by application of predetermined energy to generate a sulfonic acid residue”. The formed lower layer film for a multi-layer resist has high resistance to a 2.38 wt% TMAH developing solution usually used in a photoresist developing process, so that it does not deteriorate during the development of the upper layer resist film, and is easily formed with a photoresist stripping solution. It has been found that not only can the process be simplified because it can be removed, but also the dielectric layer of the substrate does not deteriorate due to the removal process. It was also found that resist pattern defects due to the poisoning phenomenon can be prevented.
[0025]
That is, the lower layer film forming material for a multilayer resist process according to the present invention has at least a lower layer film, an intermediate layer film, and a photoresist upper layer film which are final patterns for forming a wiring layer on a substrate with high accuracy. A material for forming the lower layer film constituting a multilayer resist for lithography, comprising a resin component having at least a substituent capable of forming a sulfonic acid residue by the removal of a terminal group by application of a predetermined energy, and a solvent. It is characterized by doing.
[0026]
In addition, the wiring forming method according to the present invention includes a step of forming an underlayer film on a substrate by using the underlayer film forming material for the multilayer resist process, and a step of using a silicon oxide film material on the underlayer film. An intermediate layer film forming step of forming an intermediate layer film by forming a photoresist upper layer film on the intermediate layer film, and exposing and developing the photoresist upper layer film to form a predetermined resist pattern. A forming step, an intermediate layer pattern forming step of removing an exposed portion of the intermediate layer film not covered with the upper layer resist pattern by dry etching, and the lower layer not covered with the mask using the intermediate layer resist pattern as a mask A lower layer pattern forming step of removing an exposed portion of the film by dry etching, and using the lower layer pattern as a mask, A wiring pattern forming step of forming a predetermined wiring pattern by etching the interlayer insulating layer, and a lower layer pattern removing step of removing the lower layer pattern remaining on the substrate after the formation of the wiring pattern with a resist stripper. It is characterized by the following.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
The underlayer film forming material for a multilayer resist process of the present invention is, as described above, a resin component having at least a substituent capable of generating a sulfonic acid residue by removing a terminal group by application of predetermined energy, and a solvent. Is characterized by containing.
[0028]
In such a configuration, the resin component has at least the following general formula (1)
Embedded image

(In the formula, n represents an integer of 1 or more, X is a linear or branched alkyl chain having 1 to 10 carbon atoms, an aromatic or alicyclic alkyl chain, an alkyl ester chain, and Y is A substituent that generates a sulfonic acid residue upon application of predetermined energy.)
It has a repeating unit represented by these.
[0029]
As the predetermined energy applied to generate the sulfonic acid residue, for example, a sulfonic acid residue can be generated by heat treatment at 80 ° C. or more. Such application of the predetermined energy is further promoted by the concerted action of heating and alkali in the peeling treatment.
[0030]
As the substituent Y in the general formula (1), -SO₃R₁Or -SO₃ ⁻R₂ ⁺(Where R₁And R₂Is preferably a monovalent organic group).
[0031]
The organic group R₁Is preferably one selected from an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group.
[0032]
Further, the organic group R₂Is preferably at least one selected from alkanolamines and alkylamines.
[0033]
Further, as a resin component having at least a substituent that generates a sulfonic acid residue by elimination of a terminal group by application of the predetermined energy, any of the resin components described above, acrylic acid or methacrylic acid or A copolymer with a derivative of the above or a mixed resin may be used.
[0034]
When the copolymer or the mixed resin is used as the resin component, the polymerization ratio or the mixing ratio is within a range that is resistant to a 2.38 wt% TMAH developer and can be removed by a resist stripper. There is no particular limitation.
[0035]
Furthermore, as a resin component having at least a substituent that generates a sulfonic acid residue by removing a terminal group by applying the predetermined energy,
For a copolymer or mixed resin of any one of the above resin components and acrylic acid or methacrylic acid or a derivative thereof, the following general formula (2)
Embedded image

(Wherein, n represents an integer of 1 or more;₃Is at least one selected from a hydrogen atom, a fluorine atom, a hydroxyl group, a carboxyl group, a hydroxyalkyl group having 1 to 5 carbon atoms and an alkoxyalkyl group having 1 to 5 carbon atoms, and Z represents 1 carbon atom. And 10 to 10 linear or branched alkyl chains, aromatic or alicyclic alkyl chains, and alkyl ester chains. )
A resin component composed of a copolymer obtained by copolymerizing a repeating unit represented by formula (1) or a mixed resin obtained by mixing a resin compound having a repeating unit represented by formula (2) may be used.
[0036]
If a copolymer is prepared using the derivative of the general formula (2) and the copolymer is used as a resin component to constitute a lower layer material, anthracene is contained in the resin component unit. Particularly, in lithography using a KrF excimer laser, absorption characteristics are high, which is preferable.
[0037]
The solvent used for the lower layer film forming material of the present invention can be used without any particular limitation as long as it is used for a conventional lower layer film forming material.
[0038]
Specifically, for example, ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl isoamyl ketone, 2-heptanone, 1,1,1-trimethyl acetone; ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl Ether, ethylene glycol monobutyl ether, ethylene glycol monoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol, diethylene glycol monoacetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol, propylene glycol monomethyl D Polyhydric alcohols such as ter, dipropylene glycol monomethyl ether, glycerin, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol and derivatives thereof; cyclic ethers such as dioxane; ethyl lactate Esters such as methyl acetate, ethyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate and ethyl 3-ethoxypropionate; sulfoxides such as dimethyl sulfoxide; dimethyl sulfone, diethyl sulfone, bis Sulfones such as (2-hydroxyethyl) sulfone and tetramethylene sulfone; N, N-dimethylformamide, N-methylformamide, N, N-dimethylacetamide, N-methylacetamide, N, N-diethylacetamide Lactams such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone; β-propiolactone, γ- Lactones such as butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone; 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, Imidazolidinones such as 3-diisopropyl-2-imidazolidinone; and the like. These may be used alone or in combination of two or more.
[0039]
The underlayer film forming material according to the present invention may contain a crosslinking agent, and such a crosslinking agent is not particularly limited as long as the resin component used in the present invention can be crosslinked. A nitrogen-containing compound having an amino group and / or an imino group, wherein at least two hydrogen atoms in all the amino groups and / or imino groups present in the nitrogen-containing compound are a hydroxyalkyl group and / or an alkoxyalkyl group Is preferred.
[0040]
The number of the substituents is 2 or more, substantially 6 or less in the nitrogen-containing compound.
[0041]
Specifically, for example, in a melamine-based compound, a urea-based compound, a guanamine-based compound, an acetoguanamine-based compound, a benzoguanamine-based compound, a glycoluril-based compound, a sucdinylamide-based compound, an ethylene urea-based compound, an amino group and / or an imino Compounds in which two or more hydrogen atoms of the group are substituted with a methylol group, an alkoxymethyl group, or both are exemplified.
[0042]
These nitrogen-containing compounds include, for example, the above melamine compounds, urea compounds, guanamine compounds, acetoguanamine compounds, benzoguanamine compounds, glycoluril compounds, succinylamide compounds, ethylene urea compounds, etc., in boiling water. By reacting with formalin to form a methylol, or by further reacting with a lower alcohol, specifically methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, etc. Obtainable.
[0043]
When a condensation reaction product of the hydroxyalkyl group and / or alkoxyalkyl group and monohydroxymonocarboxylic acid is used as the cross-linking agent, an effect of improving the shape of the lower part of the resist pattern (preventing footing) can be obtained. ,preferable.
[0044]
As the monohydroxymonocarboxylic acid, those in which a hydroxyl group and a carboxyl group are bonded to the same carbon atom or two adjacent carbon atoms are preferable from the viewpoint of preventing footing.
[0045]
When a condensation reaction product with a monohydroxymonocarboxylic acid is used, the amount of the monohydroxycarboxylic acid is 0.01 to 6 mol, preferably 0.1 to 5 mol, per 1 mol of the crosslinking agent before condensation. It is preferable to use a reaction product obtained by condensing an acid to obtain an effect of preventing footing. This condensation reaction can be performed by a conventional method.
[0046]
In the present invention, the crosslinking agent may be used alone, or two or more kinds may be used as a mixture.
[0047]
Further, an acidic compound and a surfactant can be added to the underlayer film forming material according to the present invention, if necessary.
[0048]
The effect of the addition of the acidic compound is that the property of preventing footing is improved. Examples of such an acidic compound include an inorganic acid having a sulfur-containing acid residue, an organic acid or an ester thereof, and a compound capable of generating an acid by actinic rays (an acid generator such as an onium salt). . The compounding amount of this acidic compound is 0.01 to 30 parts by mass, preferably 0.1 to 20 parts by mass, based on 100 parts by mass of the total solids. If the amount is less than the lower limit, the effect of addition cannot be obtained. If the amount exceeds the upper limit, there is a possibility that the lower part of the resist pattern may be formed.
[0049]
The effect of the addition of the surfactant is an improvement in the applicability of the underlayer film material. Examples of such a surfactant include Surflon SC-103, SR-100 (all manufactured by Asahi Glass Co., Ltd.), EF-351 (manufactured by Tohoku Fertilizer Co., Ltd.), Florad Fc-431, Florad Fc-135, and Florard. Fluorinated surfactants such as Fc-98, Florad Fc-430, Florad Fc-176 (above, manufactured by Sumitomo 3M Co., Ltd.), and Megafac R-08 (manufactured by Dainippon Ink Co., Ltd.).
[0050]
The amount of the surfactant to be added is preferably set within a range of less than 200 ppm of the total solid content in the lower film material.
[0051]
Next, the wiring forming method according to the present invention will be described in more detail with reference to FIGS. 1 (a) to 1 (d) and 2 (e) to 2 (h). In the wiring forming method of the present invention, first,
As shown in FIG. 1 (a), a thick film is formed on a semiconductor substrate 1 having a dielectric layer 1b laminated on a substrate 1a such as a silicon wafer by using the above-mentioned multilayer resist underlayer film forming material of the present invention. A resist underlayer film 2 is formed (underlayer film forming step (a)).
Next, as shown in FIG. 1B, an intermediate layer film 3 is formed on the lower layer film 2 using a spin-on glass material (intermediate layer film forming step (b)).
Next, as shown in FIG. 1 (c), a resist upper layer film 4 made of a photoresist material is formed on the intermediate layer film 3, and the resist upper layer film 4 is exposed and developed to obtain a predetermined photoresist pattern. 5 is formed (step (c) of forming an upper resist pattern).
Next, as shown in FIG. 1D, the intermediate layer film 3 is processed by dry etching using the upper resist pattern 5 as a mask to form an intermediate layer pattern 6 (intermediate layer pattern forming step (d)). ).
Next, as shown in FIG. 2E, the lower layer film 2 is processed by dry etching using the intermediate layer pattern 6 as a mask to form a lower layer pattern 7 (lower layer pattern forming step (e)).
Next, as shown in FIG. 2 (f), using the lower layer pattern 7 as a mask, the dielectric layer 1b of the substrate 1 is etched to form a predetermined wiring pattern 8 (wiring pattern forming step (f)). .
Thereafter, as shown in FIG. 2G, the lower resist pattern 7 remaining on the substrate 1 after the formation of the wiring pattern 6 is removed by a photoresist stripper (resist pattern removing step (g)).
Finally, as shown in FIG. 2H, a wiring layer 9 is formed in the wiring pattern 8 by depositing a conductor material by a vapor phase method or by embedding the conductor material (wiring layer forming step ( h)).
[0052]
The wiring forming method of the present invention is characterized by including at least these steps (a) to (g). In the description of this method, the simplest wiring structure is assumed, but it is of course applicable to a multi-layer wiring structure having a multi-layer wiring layer, and each of the upper and lower wiring layers is electrically connected by via wiring. it can. The configuration of the method of the present invention shows the minimum necessary steps. Further, this method assumes a so-called damascene process, but when a multilayer structure is obtained, a dual damascene process is necessarily employed. This dual damascene process is characterized in that a wiring groove called a trench and a via hole are continuously formed, and the formation order is opposite to the case where the trench is formed first and then the via hole is formed. In some cases, a via hole is formed first, and then a trench is formed. The present invention is applicable to both of them.
[0053]
In the wiring forming method having the above configuration, the photoresist stripping solution used in the lower layer pattern removing step (g) contains at least one selected from a water-soluble amine and a quaternary ammonium hydroxide. Is preferred. Of these, a photoresist stripper containing a quaternary ammonium hydroxide is preferably used.
[0054]
The water-soluble amine is preferably at least one selected from alkanolamines and alkylamines.
[0055]
A non-amine-based water-soluble organic solvent, water, an anticorrosive, a surfactant, and the like may be further blended with the system-based release agent containing such an amine-based release solution.
[0056]
Examples of the non-amine water-soluble organic solvent include sulfoxides such as dimethyl sulfoxide; sulfones such as dimethyl sulfone, diethyl sulfone, bis (2-hydroxyethyl) sulfone, and tetramethylene sulfone; N, N-dimethylformamide; Amides such as N-methylformamide, N, N-dimethylacetamide, N-methylacetamide, N, N-diethylacetamide; N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-hydroxymethyl-2 Lactams such as -pyrrolidone, N-hydroxyethyl-2-pyrrolidone; lactones such as β-propiolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone; 3-dimethyl-2-imidazolidinone, Imidazolidinones such as 1,3-diethyl-2-imidazolidinone and 1,3-diisopropyl-2-imidazolidinone; ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol Monoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol, diethylene glycol monoacetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, glycerin , , 2-butylene glycol, 1,3-butylene glycol, may be mentioned polyhydric alcohols and derivatives thereof such as 2,3-butylene glycol. These may be used alone or in combination of two or more.
[0057]
Further, in the method of the present invention, a step of contacting with ozone water and / or hydrogen peroxide water may be provided prior to the peeling treatment of the lower layer film. It is preferable to use ozone water obtained by dissolving ozone gas in pure water by means such as bubbling. Further, the ozone content concentration may be used between 1 ppm or more and the saturation concentration, and the hydrogen peroxide solution may be used as an aqueous solution having a concentration of 0.1 to 60% by mass. Examples of the contact method include an immersion method, a paddle method, and a shower method. By performing such a pretreatment, the performance of removing the resist lower layer film and the resist upper layer film can be improved.
[0058]
In the method of the present invention, a photoresist composition for forming a resist upper layer film includes KrF, ArF, F₂Excimer laser or a photoresist material commonly used for electron beams can be used in a usual manner.
[0059]
Further, in the method of the present invention, the exposure and the development can be carried out by a usual process in ordinary lithography.
[0060]
Various silicon-containing polymers can be used as a silicon oxide film material for forming the intermediate layer. Among them, a spin-on-glass material can be preferably used. As such a spin-on-glass material,
(A) Si (OR¹)_a(OR²)_b(OR³)_c(OR⁴)_d
(Where R¹, R², R³, And R⁴Are each independently an alkyl or phenyl group having 1 to 4 carbon atoms, a, b, c, and d are 0 ≦ a ≦ 4, 0 ≦ b ≦ 4, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4 And an integer satisfying the condition of a + b + c + d = 4. ), A compound represented by
(B) R⁵Si (OR⁶)_e(OR⁷)_f(OR⁸)_g
(Wherein, R5 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms;⁶, R⁷, And R⁸Is an alkyl group or a phenyl group having 1 to 3 carbon atoms, e, f, and g are 0 ≦ e ≦ 3, 0 ≦ f ≦ 3, 0 ≦ g ≦ 3, and e + f + g = 3. Is an integer that satisfies A), and
(C) R⁹R¹⁰Si (OR¹¹)_h(OR¹²)_i
(Where R⁹And R¹⁰Is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R¹¹And R¹²Is an alkyl or phenyl group having 1 to 3 carbon atoms, and h and i are integers satisfying 0 ≦ h ≦ 2, 0 ≦ i ≦ 2, and satisfying the condition of h + i = 2. ) Is obtained by hydrolyzing at least one compound selected from the compounds represented by the formula (1) in the presence of water by the action of an acid.
[0061]
Examples of the compound (A) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetraphenyloxysilane, trimethoxymonoethoxysilane, dimethoxydiethoxysilane, triethoxymonomethoxysilane, and triethoxymonomethoxysilane. Methoxymonopropoxysilane, monomethoxytributoxysilane, monomethoxytriphenyloxysilane, dimethoxydipropoxysilane, tripropoxymonomethoxysilane, trimethoxymonobutoxysilane, dimethoxydibutoxysilane, triethoxymonopropoxysilane, diethoxydipropoxy Silane, tributoxy monopropoxy silane, dimethoxy monoethoxy monobutoxy silane, diethoxy monomethoxy monobutoxy silane, diethoxy Nopropoxy monobutoxy silane, dipropoxy monomethoxy monoethoxy silane, dipropoxy monomethoxy monobutoxy silane, dipropoxy monoethoxy monobutoxy silane, dibutoxy monomethoxy monoethoxy silane, dibutoxy monoethoxy monopropoxy silane, monomethoxy monoethoxy Examples thereof include tetraalkoxysilanes such as propoxymonobutoxysilane and oligomers thereof, and among them, tetramethoxysilane, tetraethoxysilane and oligomers thereof are preferable.
[0062]
Examples of the compound (B) include trimethoxysilane, triethoxysilane, tripropoxysilane, triphenyloxysilane, dimethoxymonoethoxysilane, diethoxymonomethoxysilane, dipropoxymonomethoxysilane, and dipropoxy. Monoethoxysilane, diphenyloxylmonomethoxysilane, diphenyloxymonoethoxysilane, diphenyloxymonopropoxysilane, methoxyethoxypropoxysilane, monopropoxydimethoxysilane, monopropoxydiethoxysilane, monobutoxydimethoxysilane, monophenyloxydiethoxysilane, Methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltripropoxysilane, L-triphenyloxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriphenyloxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltripropoxysilane, butyltriphenyloxysilane, methylmonomethoxydiethoxysilane, ethyl Monomethoxydiethoxysilane, propylmonomethoxydiethoxysilane, butylmonomethoxydiethoxysilane, methylmonomethoxydipropoxysilane, methylmonomethoxydiphenyloxysilane, ethylmonomethoxydipropoxysilane, ethylmonomethoxydiphenyloxysilane, propylmono Methoxydipropoxysilane, propylmonomethoxydiphenyloxysilane, butylmonomethoxydipropoxysilane, butyl Nomethoxydiphenyloxysilane, methylmethoxyethoxypropoxysilane, propylmethoxyethoxypropoxysilane, butylmethoxyethoxypropoxysilane, methylmonomethoxymonoethoxymonobutoxysilane, ethylmonomethoxymonoethoxymonobutoxysilane, propylmonomethoxymonoethoxymonobutoxysilane And butylmonomethoxymonoethoxymonobutoxysilane, among which trimethoxysilane and triethoxysilane are preferred.
[0063]
Further, as the compound (C), for example, dimethoxysilane, diethoxysilane, dipropoxysilane, diphenyloxysilane, methoxyethoxysilane, methoxypropoxysilane, methoxyphenyloxysilane, ethoxypropoxysilane, ethoxyphenyloxysilane, Methyldimethoxysilane, methylmethoxyethoxysilane, methyldiethoxysilane, methylmethoxypropoxysilane, methylmethoxyphenyloxysilane, ethyldipropoxysilane, ethylmethoxypropoxysilane, ethyldiphenyloxysilane, propyldimethoxysilane, propylmethoxyethoxysilane, propyl Ethoxypropoxysilane, propyldiethoxysilane, propyldiphenyloxysilane, butyldimethoxysilane Butylmethoxyethoxysilane, butyldiethoxysilane, butylethoxypropoxysilane, butyldipropoxysilane, butylmethylphenyloxysilane, dimethyldimethoxysilane, dimethylmethoxyethoxysilane, dimethyldiethoxysilane, dimethyldiphenyloxysilane, dimethylethoxypropoxysilane, Dimethyldipropoxysilane, diethyldimethoxysilane, diethylmethoxypropoxysilane, diethyldiethoxypropoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, dipropyldiphenyloxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, dibutyldipropoxysilane , Dibutylmethoxyphenyloxysilane, methylethyldimethoxysilane, methyl Tyldiethoxysilane, methylethyldipropoxysilane, methylethyldiphenyloxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, methylbutyldimethoxysilane, methylbutyldiethoxysilane, methylbutyldipropoxysilane, methylethylethoxypropoxysilane , Ethylpropyldimethoxysilane, ethylpropylmethoxyethoxysilane, dipropyldimethoxysilane, dipropylmethoxyethoxysilane, propylbutyldimethoxysilane, propylbutyldiethoxysilane, dibutylmethoxypropoxysilane, butylethoxypropoxysilane, and the like. Dimethoxysilane, diethoxysilane and methyldimethoxysilane are preferred.
[0064]
As an etching gas for dry-etching the spin-on-glass material as the intermediate layer, a gas mainly containing a fluorocarbon-based gas is used.
[0065]
Further, as an etching gas for dry-etching the lower film material of the present invention, a gas mainly containing an oxygen-based gas is used.
[0066]
【Example】
Hereinafter, examples of the present invention will be described. The following examples are merely exemplifications for suitably describing the present invention, and do not limit the present invention at all.
[0067]
(Examples 1 to 4)
The following resin compositions (A), (B), (C) and (D) were prepared as lower layer film forming materials.
[0068]
(A) A resin composition in which a resin component composed of ethyl p-styrenesulfonate is dissolved in a solvent composed of γ-butyrolactone / ethyl lactate (2: 8) to adjust the solid content to 6 wt%.
[0069]
(B) A resin component composed of ethyl p-styrenesulfonate: hydroxyethyl acrylate (= 5: 5) and Cymel 1172 (tetramethylol glycoluril manufactured by Mitsui Cyanamid Co., Ltd.) in an amount equivalent to 20% by weight of the resin component, A resin composition dissolved in a solvent composed of ethyl lactate and having a solid content adjusted to 6 wt%.
[0070]
(C) A resin component composed of ethyl p-styrenesulfonate: 9-hydroxyanthracenyl acrylate (= 5: 5) is dissolved in a solvent composed of γ-butyrolactone / ethyl lactate (2: 8), and the solid content concentration is dissolved. Was adjusted to 6 wt%.
[0071]
(D) Ethyl p-styrenesulfonate: hydroxyethyl acrylate: 9-hydroxyanthracenyl acrylate (= 4: 3: 3) and Cymel 1172 (Mitsui Cyanamid Co., Ltd.) in an amount equivalent to 20% by weight of the resin. Tetramethylol glycoluril) and Megafac R08 (a fluorosurfactant manufactured by Dai Nippon Ink Co., Ltd.) in an amount equivalent to 1000 ppm of the above two solid contents were dissolved in a solvent composed of ethyl lactate, and the solid content concentration was changed. Was adjusted to 6 wt%.
[0072]
On the other hand, as shown in FIG. 3A, a first barrier layer 13 made of a SiN film is formed as a first layer on a substrate 12 having a copper wiring layer 11 formed on the surface, and a low dielectric material is formed as a second layer. A first low dielectric layer 14 made of a material (trade name: OCD-T12, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is formed, a second barrier layer 15 made of a SiN film is formed as a third layer, and a fourth layer is formed. A second low dielectric layer 16 made of a low dielectric material (trade name: OCD-T12, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was formed.
[0073]
Next, as shown in FIG. 3B, a photoresist layer 17 was formed on the second low dielectric layer 16, and the photoresist layer 17 was processed by lithography to obtain a resist pattern 18. Using the obtained resist pattern 18 as a mask, a via hole 19 penetrating through the first to fourth layers and communicating with the copper wiring layer 11 was formed. After the formation of the via hole 19, the resist pattern 18 was removed.
[0074]
As shown in FIG. 3C, the above-mentioned (A), (B), (C) and (D) are formed on the second low dielectric layer 16 after the formation of the via hole 19 and the removal of the resist pattern 18. ) Was applied and the via holes were buried, and then heat-treated at 200 ° C. for 90 seconds to form a lower layer film 20 having a thickness of 3000 ° on the second low dielectric layer. . On the lower layer film 20, a resin composition containing a spin-on-glass material as a main component was applied to form an intermediate layer film 21 having a thickness of 150 °. Further, on this intermediate layer film 21, a photoresist composition (TARF-P6071 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied and heated at 120 ° C. for 90 seconds to form an upper film 22 having a thickness of 400 nm. did. Next, the upper layer film 22 was exposed, heated after exposure (120 ° C., 90 seconds), and developed to form an upper layer resist pattern 23 for forming a trench.
[0075]
Using the upper resist pattern 23 as a mask, the intermediate layer film 21 was processed using a fluorocarbon-based etching gas to obtain an intermediate layer film pattern. Then, using the intermediate layer film pattern as a mask and using an oxygen-based etching gas, as shown in FIG. 3D, the lower layer film 20 is processed to form a lower layer pattern 24, and the intermediate layer resist The final resist pattern for forming the trench was obtained by removing the pattern. At this point, the surface of the substrate was observed with a scanning electron microscope. As a result, there was no pattern defect of the resist pattern due to the adverse effect of poisoning, and no damage was observed on the low dielectric layer constituting the trench.
[0076]
In the normal wiring layer forming process, subsequently, the second low dielectric layer 16 is etched using the final resist pattern (lower resist pattern) as a mask, as shown in FIG. Then, a trench 25 having a predetermined pattern reaching the second barrier layer 15 is formed. Thereafter, copper is buried in the via hole 19 and the trench 25 to form a multilayer wiring structure.
[0077]
In the present embodiment, the process of removing the resist pattern for rework is performed as follows, assuming that a situation in which a defect has occurred in patterning has been confirmed when the final resist pattern 24 has been obtained. did.
[0078]
The substrate having the lower resist pattern 24 is immersed in a photoresist stripper containing a mixed solvent of dimethyl sulfoxide and monoethanolamine (mixing ratio = 7: 3) adjusted to 100 ° C. for 20 minutes, and the resist pattern is stripped. went. After the peeling treatment, the surface of the substrate was observed with a scanning microscope. However, when any of the resin compositions (A) to (D) was used as the material of the lower layer film, no residue of the resist pattern was present. It was confirmed that the removal of the pattern was surely performed. Further, no damage to the low dielectric layer 16 due to the resist pattern peeling treatment was observed.
[0079]
(Example 5)
In the resin composition of (C), "TPS-109 which is a photoacid generator (manufactured by Midori Kagaku Co., Ltd.)" in an amount equivalent to 3 wt% of the resin component is additionally blended, and a new resin composition ( C2) was prepared. A resist pattern was formed in the same manner as in Example 1 except that the resin composition (C2) was used. As a result, it was confirmed that a rectangular resist pattern having excellent dimensional controllability could be obtained, and that the effect of poisoning from the low dielectric layer could be suppressed by the lower layer material of the present invention. After the resist pattern stripping process was performed, the surface of the low dielectric layer was observed with a scanning microscope. However, no residue of the resist pattern was seen on the substrate surface after the stripping process, and the removal was sufficiently performed. It was confirmed that. Furthermore, there was no damage to the low dielectric layer.
[0080]
(Comparative Example 1)
A lower layer material is formed from a resin composition obtained by dissolving hexamethoxymethylated melamine in propylene glycol monomethyl ether acetate.₂Except for performing the plasma ashing, the same operation as in the above example was performed to form a resist pattern and to remove the resist pattern. As a result, poisoning occurred in the trench forming photoresist pattern, and a portion where a pattern image could not be formed occurred. In addition, the pattern O₂Serious damage occurred to the low dielectric layer due to the peeling treatment by plasma ashing.
[0081]
(Comparative Example 2)
In Comparative Example 1, the removal of the lower layer pattern was performed using the photoresist stripping solution used in Example. As a result, the pattern could not be removed.
[0082]
【The invention's effect】
As described above, the underlayer film-forming material for a multilayer resist process of the present invention includes a resin component having at least a substituent from which a terminal group is eliminated by application of a predetermined energy to generate a sulfonic acid residue, and a solvent. And is characterized by containing. In such a configuration, the resin component has at least the following general formula (1)
Embedded image

(In the formula, n represents an integer of 1 or more, X is a linear or branched alkyl chain having 1 to 10 carbon atoms, an aromatic or alicyclic alkyl chain, an alkyl ester chain, and Y is A substituent that generates a sulfonic acid residue upon application of predetermined energy.)
What has a repeating unit represented by these is preferable.
[0083]
With such a configuration, the present invention can obtain the following effects.
(1) Since the lower layer film of the present invention can be removed with a photoresist stripper, the lower layer film may be made of a low dielectric material having a dielectric constant (k) of 3.0 or less.₂It is suitable as a lower layer material used in a lithography process on a semiconductor substrate on which a material having low ashing plasma resistance is laminated.
(2) Further, when it becomes necessary to recover the substrate due to poor lithography, the lower layer film can be easily removed by a wet process that does not damage the substrate, so that the rework process for recovering the substrate is performed reliably and easily. be able to. As a result, O₂It is possible to avoid a situation in which the substrate regenerating process becomes difficult due to the insolubilization of the silicon-containing resist due to the alteration, the insolubilization of the lower layer film, and the like, which occur when plasma ashing is used.
(3) Further, if the lower layer film of the multi-layer resist is also used as an embedding material in the dual damascene process, the deterioration of the resist pattern due to the poisoning phenomenon which is likely to occur when forming the dual damascene structure in the low dielectric layer. It can be prevented or deterred.
[Brief description of the drawings]
FIGS. 1A to 1D are diagrams for explaining a wiring forming method using a lower layer film forming material for a multilayer resist process according to the present invention, wherein FIGS. .
2 (a) to 2 (f) are diagrams for explaining a wiring forming method using a lower layer film forming material for a multilayer resist process of the present invention, wherein (e) to (f) use lithography following FIG. 1 (d); It is a process drawing of the latter half of wiring formation.
FIG. 3 is a view for explaining an embodiment in which a wiring forming method using a lower layer film forming material for a multilayer resist process of the present invention is applied to formation of a dual damascene structure; FIG. 4 is a process chart until a is formed.
[Explanation of symbols]
1 semiconductor substrate
1a Substrate
1b Dielectric layer
2 Lower layer film
3 Interlayer film
4 Resist upper layer film
5 Upper layer resist pattern
6 Intermediate layer pattern
7 Lower layer pattern
8 Wiring pattern
9 Wiring layer
11 Wiring layer
12 Substrate
13 First etching stopper layer
14 First low dielectric layer
15 Second etching stopper layer
16 Second low dielectric layer
17 Photoresist layer
18 resist pattern
19 Beer Hall
20 Lower layer film
21 Interlayer film
22 Resist upper layer film
23 Upper layer resist pattern
24 Lower layer pattern
25 trench

Claims (13)

A material for forming the lower layer film constituting a multilayer resist process comprising at least a lower layer film, an intermediate layer film, and a photoresist upper layer film to be a final resist pattern for forming a wiring layer on a substrate with high precision, ,
A material for forming an underlayer film for a multilayer resist process, comprising: a resin component having at least a substituent from which a terminal group is eliminated by application of predetermined energy to generate a sulfonic acid residue; and a solvent. The resin component has at least the following general formula (1)

(In the formula, n represents an integer of 1 or more, X is a linear or branched alkyl chain having 1 to 10 carbon atoms, an aromatic or alicyclic alkyl chain, an alkyl ester chain, and Y is A substituent that generates a sulfonic acid residue upon application of predetermined energy.)
The material for forming an underlayer film for a multilayer resist process according to claim 1, comprising a repeating unit represented by the following formula: The underlayer film forming material for a multilayer resist process according to claim 1, wherein the predetermined energy applied to generate the sulfonic acid residue is heat of 80 ° C or higher. Formula (1) substituent Y is _-SO 3 _{R 1} or _-SO ³ - (wherein, _{R 1} and _{R 2} is a monovalent organic group) _R ^{2 +} claims, characterized in that a 2 4. The material for forming a lower layer film for a multilayer resist process according to item 3. The organic group R ₁ is, the lower layer material for multilayer resist process of claim 4, characterized in that the one selected from among alkyl or hydroxyalkyl group, having 1 to 10 carbon atoms. The organic group R ₂ is, underlayer film forming material for a multilayer resist process of claim 4, wherein the at least one selected from alkanolamines, and alkylamines. The resin component having at least a substituent from which a terminal group is eliminated by application of the predetermined energy to generate a sulfonic acid residue, the resin component according to any one of claims 4 to 6, and acrylic acid or 3. The material for forming an underlayer film for a multilayer resist process according to claim 1, wherein the material is a copolymer or a mixed resin with methacrylic acid or a derivative thereof. A resin component having at least a substituent that generates a sulfonic acid residue by elimination of a terminal group when the predetermined energy is applied,
A copolymer or a mixed resin of the resin component according to any one of claims 3 to 6 with acrylic acid, methacrylic acid, or a derivative thereof, has the following general formula (2):

(In the formula, n represents an integer of 1 or more, and R ₃ represents a hydrogen atom, a fluorine atom, a hydroxyl group, a carboxyl group, a hydroxyalkyl group having 1 to 5 carbon atoms, or an alkoxyalkyl group having 1 to 5 carbon atoms. And Z is a linear or branched alkyl chain having 1 to 10 carbon atoms, an aromatic or alicyclic alkyl chain, or an alkyl ester chain.)
A resin component comprising a copolymer obtained by copolymerizing a repeating unit represented by formula (1) or a mixed resin obtained by mixing a resin compound having a repeating unit represented by formula (2). 3. The material for forming a lower layer film for a multilayer resist process according to 1 or 2. 9. The material for forming a lower layer film for a multilayer resist process according to claim 1, further comprising a crosslinking agent. An underlayer film forming step of forming a resist underlayer film on a substrate using the underlayer film forming material for a multilayer resist process according to any one of claims 1 to 9,
An intermediate layer film forming step of forming a resist intermediate layer film using a silicon oxide film material on the lower layer film,
Forming a photoresist upper layer film on the intermediate layer film, exposing and developing the photoresist upper layer film, an upper resist pattern forming step of forming a predetermined resist pattern,
An intermediate layer pattern forming step of removing exposed portions of the intermediate layer film that are not covered by the upper layer resist pattern by dry etching,
A lower resist pattern forming step of removing, by dry etching, an exposed portion of the lower film that is not covered with the mask using the intermediate layer pattern as a mask,
Using the lower layer pattern as a mask, a wiring pattern forming step of forming a predetermined wiring pattern by etching an interlayer insulating layer on the substrate,
A lower layer pattern removing step of removing the lower layer pattern remaining on the substrate after the formation of the wiring pattern with a resist stripper,
A wiring forming method, comprising: The wiring formation according to claim 10, wherein the resist stripping solution used in the lower layer pattern forming step contains at least one selected from a water-soluble amine and a quaternary ammonium hydroxide. Method. The method according to claim 11, wherein the water-soluble amine is at least one selected from alkanolamines and alkylamines. (A) Si (OR ¹ ) _a (OR ² ) _b (OR ³ ) _c (OR ⁴ ) _d as a silicon oxide film material for forming the intermediate layer.
(Wherein, R ¹ , R ² , R ³ , and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or a phenyl group, a, b, c, and d are 0 ≦ a ≦ 4,0 ≦ b ≦ 4, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, and an integer satisfying the condition of a + b + c + d = 4.)
(B) R ⁵ Si (OR ⁶ ) _e (OR ⁷ ) _f (OR ⁸ ) _g
(Wherein, R ⁵ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ⁶ , R ⁷ , and R ⁸ are an alkyl group or a phenyl group each having 1 to 3 carbon atoms, and e, f, and g are And an integer satisfying 0 ≦ e ≦ 3, 0 ≦ f ≦ 3, 0 ≦ g ≦ 3 and satisfying the condition of e + f + g = 3), and (C) R ⁹ R ¹⁰ Si (OR ¹¹ ) _h (OR ¹² ) _i
(Wherein, R ⁹ and R ¹⁰ are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ¹¹ and R ¹² are an alkyl group or a phenyl group each having 1 to 3 carbon atoms, and h and i are 0 ≦ h ≦ 2, 0 ≦ i ≦ 2, and an integer that satisfies the condition of h + i = 2) that is obtained by hydrolyzing at least one compound selected from spin-on-glass materials represented by the following formula: The wiring forming method according to any one of claims 10 to 12, wherein:

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