JP3955220B2 - Cleaning method - Google Patents

Description

【００２３】
この時、第１段、第２段、第ｎ段の解離定数Ｋａ₁ 、Ｋａ₂ 、Ｋａ_n は以下のように定義される。
Ｋａ₁ ＝［Ｈ_n-1 Ａ^- ］［Ｈ⁺ ］／［Ｈ_n Ａ］
Ｋａ₂ ＝［Ｈ_n-2 Ａ^2-］［Ｈ⁺ ］／［Ｈ_n-1 Ａ^- ］
Ｋａ_n ＝［Ａ^n-］［Ｈ⁺ ］／［ＨＡ^(n-1)-］
【００２４】
したがって、Ｋａ_n の逆数の対数、つまり第ｎ段の解離指数はｐＫａ_n と表わされる。
ｐＫａ_n ＝ｌｏｇ（１／Ｋａ_n ）＝−ｌｏｇＫａ_n
【００２５】
本発明において、ｐＫａ_n は、化学便覧改訂４版、基礎編II（日本化学会編）、II−３１７頁、表１０・１８ 水溶液中の無機化合物の酸解離定数（２５℃）、II−３１７〜３２１頁、表１０・１９ 有機化合物の酸解離定数（２５℃）、理化学辞典第４版（岩波書店）より与えられ、また、前記に記載のないものについてはイオン平衡（化学同人）５３頁、６６〜６８頁に記載の通常の実験方法に基づいて求めることができる。
【００２６】
（ａ）成分としては、例えば、オキソ酸、水素酸、ペルオキソ酸等の無機酸；カルボン酸、チオカルボン酸、過酸、メルカプタン、スルホン酸、ホスファチジン酸、ジチオカルボン酸、スルフィン酸、スルフェン酸、ホスホン酸、ホスフィン酸、炭酸エステル、硫酸エステル、リン酸エステル、ホウ酸エステル、等の有機酸が挙げられる。
【００２７】
無機酸の具体例としては、炭酸、重炭酸、ホウ酸、ヨウ素酸、硝酸、硫酸、次亜臭素酸、次亜塩素酸、亜塩素酸、過塩素酸、亜硝酸、亜硫酸等のオキソ酸；臭化水素酸、塩酸、フッ化水素酸、ヨウ化水素酸、硫化水素酸等の水素酸；ペルオキソ硝酸、ペルオキソ硫酸、ペルオキソ二硫酸等のペルオキソ酸等が挙げられる。
【００２８】
また、有機酸の中では、デポ洗浄性及び金属材料に対する腐食防止の観点から、カルボン酸が好ましい。カルボン酸としては、直鎖飽和モノカルボン酸、直鎖不飽和モノカルボン酸、分岐鎖飽和モノカルボン酸、分岐鎖不飽和モノカルボン酸、飽和多価カルボン酸、不飽和多価カルボン酸、ヒドロキシカルボン酸、アルコキシカルボン酸、芳香環を有するカルボン酸、脂環を有するカルボン酸等が挙げられる。
【００２９】
カルボン酸としては、式（II）：
Ｂ−〔（Ｒ³ ）_p −（ＣＯＯＨ）_q 〕_r （II）
（式中、Ｒ³ は水素原子、炭素数１〜４０の直鎖状、分岐鎖状若しくは環状の骨格からなる飽和又は不飽和炭化水素基であり、Ｒ³ の炭化水素基は１〜５個の酸素原子又は硫黄原子を有していてもよく、Ｒ³ の炭素原子に結合している水素原子は−ＯＨ基又は−ＳＨ基で置換されていてもよく、ｑ個の−ＣＯＯＨ基はＲ³ の同一炭素原子に１個又は複数個結合していてもよく、ｐは０又は１、ｑは１〜４０の整数、ｒは１〜３の整数、Ｂは存在しないか又は−Ｏ−基、−ＣＯ−基若しくは−Ｓ−基を示す。）
で表されるカルボン酸が好ましい。
【００３０】
式（II）において、デポ洗浄性及び金属材料に対する腐食防止の観点から、Ｒ³ は水素原子、炭素数１〜１８の直鎖状の飽和炭化水素基、炭素数３〜１８の分岐鎖状の飽和炭化水素基、炭素数２〜１８の直鎖状の不飽和炭化水素基、炭素数３〜１８の分岐鎖状の不飽和炭化水素基、炭素数３〜１８の脂環を有する飽和又は不飽和炭化水素基、炭素数６〜１８の芳香環を有する飽和又は不飽和炭化水素基が好ましい。さらには、Ｒ³ は炭素数１〜１２の直鎖状の飽和炭化水素基、炭素数３〜１２の分岐鎖状の飽和炭化水素基、炭素数２〜１２の直鎖状の不飽和炭化水素基、炭素数３〜１２の分岐鎖状の不飽和炭化水素基、炭素数３〜１２の脂環を有する飽和又は不飽和炭化水素基、炭素数６〜１２の芳香環を有する飽和又は不飽和炭化水素基がより好ましい。特に、Ｒ³ は炭素数１〜６の直鎖状の飽和炭化水素基、炭素数３〜６の分岐鎖状の飽和炭化水素基、炭素数２〜６の直鎖状の不飽和炭化水素基、炭素数３〜６の分岐鎖状の不飽和炭化水素基、炭素数３〜６の脂環を有する飽和又は不飽和炭化水素基、炭素数６〜８の芳香環を有する飽和又は不飽和炭化水素基が最も好ましい。また、Ｒ³ の炭化水素基に酸素原子又は硫黄原子を有する場合、それぞれ１〜２個がより好ましい。
【００３１】
また、式（II）において、ｑはデポ洗浄性及び金属材料に対する腐食防止の観点から、１〜１８の整数が好ましく、１〜１２の整数がより好ましく、１〜６の整数がさらに好ましく、１〜２の整数が特に好ましい。
【００３２】
好ましいカルボン酸の具体例としては、蟻酸、酢酸、プロピオン酸等の炭素数が１〜１８の直鎖飽和モノカルボン酸；アクリル酸、クロトン酸、ビニル酢酸、４−ペンテン酸、６−ヘプテン酸、２−オクテン酸、ウンデシレン酸、オレイン酸等の直鎖不飽和モノカルボン酸；イソ酪酸、イソバレリン酸、ピバリン酸、２−メチル酪酸、２−メチルバレリン酸、２, ２−ジメチル酪酸、２−エチル酪酸、tert−ブチル酪酸、２, ２−ジメチルペンタン酸、２−エチルペンタン酸、２−メチルヘキサン酸、２−エチルヘキサン酸、２, ４−ジメチルヘキサン酸、２−メチルヘプタン酸、２−プロピルペンタン酸、３, ５, ５−トリメチルヘキサン酸、２−メチルオクタン酸、２−エチルヘプタン酸、２−エチル−２, ３, ３−トリメチル酪酸、２, ２, ４, ４−テトラメチルペンタン酸、２, ２−ジイソプロピルプロピオン酸等の分岐鎖飽和モノカルボン酸；メタクリル酸、チグリン酸、３, ３−ジメチルアクリル酸、２, ２−ジメチル−４−ペンテン酸、２−エチル−２−ヘキセン酸、シトロネリル酸等の分岐鎖不飽和モノカルボン酸；シュウ酸、マロン酸、メチルマロン酸、エチルマロン酸、ジメチルマロン酸、コハク酸、メチルコハク酸、２, ２−ジメチルコハク酸、グルタル酸、アジピン酸、３−メチルアジピン酸、セバシン酸、ヘキサデカンジオン酸、１，２，３−プロパントリカルボン酸、１，２，３，４−ブタンテトラカルボン酸、ポリアクリル酸、ポリマレイン酸等の飽和多価カルボン酸；マレイン酸、フマル酸、シトラコン酸、メサコン酸、cis-アコニット酸、trans-アコニット酸等の不飽和多価カルボン酸；乳酸、グルコン酸、酒石酸、リンゴ酸、クエン酸等のヒドロキシカルボン酸；メトキシ酢酸、エトキシ酢酸等のアルコキシカルボン酸；安息香酸、テレフタル酸、トリメリット酸、ナフトエ酸等の芳香環を有するカルボン酸；シクロヘキサンカルボン酸、シクロヘキサンプロピオン酸、シクロヘキサン酪酸、シクロペンタンカルボン酸等の脂環を有するカルボン酸等が挙げられる。
【００３３】
これらの中で、蟻酸、酢酸、プロピオン酸等の炭素数が１〜６の直鎖飽和モノカルボン酸；シュウ酸、マロン酸、コハク酸等の飽和多価カルボン酸；乳酸、グルコン酸、酒石酸、リンゴ酸、クエン酸等のヒドロキシカルボン酸；メトキシ酢酸、エトキシ酢酸等のアルコキシカルボン酸がより好ましい。特に、蟻酸、酢酸、シュウ酸、マロン酸、コハク酸、乳酸、グルコン酸、酒石酸、リンゴ酸及びクエン酸が好ましい。
【００３４】
前記カルボン酸の分子量は、特に限定されないが、デポ洗浄性及び金属材料に対する腐食防止の観点から、４６〜４００が好ましく、より好ましくは４６〜２００である。
【００３５】
かかる酸の塩としては、酸と塩基性有機化合物又は塩基性無機化合物との塩等が挙げられる。塩基性有機化合物としては、一級アミン、二級アミン、三級アミン、イミン、アルカノールアミン、アミド、塩基性の複素環式化合物及び水酸化第四級アンモニウム等が挙げられる。塩基性無機化合物としては、アンモニア、水酸化ナトリウム、水酸化カリウム、水酸化カルシウム等が挙げられる。これらの中では、金属イオンの混入を避ける観点から、酸のアンモニウム塩及び酸と塩基性有機化合物との塩が好ましい。特にアンモニウム塩は、Ｗ又はＷ合金の配線又は電極において生成するデポが酸化タングステンであるため、タングステンのアンモニウム塩を形成することにより水溶性となり、容易に剥離することから特に好ましい。これらの酸の塩は、単独で又は２種以上を混合して使用してもよい。
【００３６】
また、前記酸及び／又はその塩は、単独で又は２種以上を混合して使用してもよい。
【００３７】
かかる（ａ）酸及び／又はその塩の洗浄剤組成物中における含有量は、優れたデポ洗浄性を得る観点から、０．０１〜６５重量％が好ましく、デポ洗浄性及び金属材料に対する腐食防止の観点から、０．０５〜５５重量％がより好ましく、更に０．１〜３５重量％が好ましく、特に０．５〜２０重量％が好ましい。
【００３８】
本発明において用いられる（ｂ）水は、洗浄剤組成物が半導体素子やＬＣＤの製造分野で使用されることを考慮して、イオン交換水、純水や超純水等のイオン性物質やパーティクル等を極力低減させたものが好ましい。
【００３９】
（ｂ）水の洗浄剤組成物中における含有量は、デポ洗浄性を向上させる観点から３０〜９９重量％が好ましい。本発明において、かかる範囲に水の含有量を調節することにより、優れたデポ洗浄性及び金属材料に対する腐食防止効果を有する洗浄剤組成物を得ることができる。また、水の含有量は、デポ洗浄性及び金属材料に対する腐食防止の観点から、より好ましくは４０〜９７重量％、さらに好ましくは６０〜９５重量％である。
【００４０】
（ｃ）分子中に窒素原子を含むキレート剤は、分子中に１〜３級のアミノ基及び／又は４級アンモニウム塩を含み、分子量が４０〜３０００の化合物を指す。キレート剤とは、水溶性の金属キレートを生成するような金属封鎖剤をいい、具体的には、金属イオンと配位結合して該金属イオンを包み込む多座配位子をいう。なお、金属イオンに配位結合する能力をもった電子供与体を配位子と呼び、配位子１分子に電子供与基を２、３、４個持つものをそれぞれ２座、３座、４座配位子といい、２座配位子以上を総称して、多座配位子という。（ｃ）分子中に窒素原子を含むキレート剤の例としては、「金属キレート(III) 」（上野景平、阪口武一編集、南江堂発行、昭和４２年第１版）の「安定度定数表」１５〜５５頁に記載のアミン及びその誘導体、アミノポリカルボン酸並びにアミノ酸からなる群より選ばれた１種以上が挙げられる。
【００４１】
アミン及びその誘導体としては、式：
Ｒ⁴ Ｒ⁵ Ｒ⁶ Ｎ
（式中、Ｒ⁴ 、Ｒ⁵ 及びＲ⁶ は水素原子、炭素数１〜２０の直鎖状、分岐鎖状若しくは環状の骨格からなる飽和又は不飽和炭化水素基であり、Ｒ⁴ 、Ｒ⁵ 及びＲ⁶ の炭化水素基は１〜５個の酸素原子、窒素原子又は硫黄原子を有していてもよく、Ｒ⁴ 、Ｒ⁵ 及びＲ⁶ の炭素原子に結合している水素原子は−ＯＨ基、−ＮＨ₂ 基又は−ＳＨ₂ 基で置換されていてもよい。なお、Ｒ⁴ 、Ｒ⁵ 及びＲ⁶ はそれぞれ同一であっても異なっていてもよい。）
で表される化合物が挙げられる。
【００４２】
その具体例としては、エチレンジアミン、Ｎ−メチルエチレンジアミン、Ｎ−エチルエチレンジアミン、Ｎ−（２−ヒドロキシエチル）エチレンジアミン、トリメチレンジアミン、テトラメチレンジアミン、ペンタメチレンジアミン、トリエチレンジアミン、イミダゾール、ヒスタミン等が挙げられる。
【００４３】
アミノポリカルボン酸としては、式：
Ｒ⁴ ＮＹ₂ 、ＮＹ₃ 、Ｒ⁴ ＹＮ−ＣＨ₂ ＣＨ₂ −ＮＹＲ⁵ 、Ｒ⁴ ＹＮ−ＣＨ₂ ＣＨ₂ −ＮＹ₂ 、Ｙ₂ Ｎ−（ＣＨ₂ ）_u −ＮＹ₂
（式中、Ｒ⁴ 及びＲ⁵ は前記と同じ、Ｙは−ＣＨ₂ ＣＯＯＨ又は−ＣＨ₂ −ＣＨ₂ ＣＯＯＨを示す。ｕは１〜１０の整数を示す。）
で表される化合物が挙げられる。
【００４４】
その具体例としては、Ｒ⁴ ＮＹ₂ 型であるイミノジ酢酸、ヒドロキシエチルイミノジ酢酸；ＮＹ₃ 型であるニトリロトリ酢酸；Ｒ⁴ ＹＮ−ＣＨ₂ ＣＨ₂ −ＮＹＲ⁵ 型であるＮ，Ｎ’−エチレンジアミンジ酢酸；Ｒ⁴ ＹＮ−ＣＨ₂ ＣＨ₂ −ＮＹ₂ 型であるＮ’−ヒドロキシエチル−Ｎ，Ｎ，Ｎ’−トリ酢酸；Ｙ₂ Ｎ−（ＣＨ₂ ）_u −ＮＹ₂ 型であるエチレンジアミンテトラ酢酸等が挙げられる。中でも、Ｗ又はＷ合金を有する配線又は電極のデポ洗浄性の観点から、Ｎ，Ｎ’−エチレンジアミンジ酢酸、Ｎ’−ヒドロキシエチル−Ｎ，Ｎ，Ｎ’−トリ酢酸及びエチレンジアミンテトラ酢酸が好ましい。
【００４５】
アミノ酸は、分子内にカルボキシル基（ＣＯＯＨ）とアミノ基（ＮＨ₂ ）を有していればよい。その具体例としては、グリシン、アラニン、β−アラニン、ザルコシン、アスパラギン酸、アスパラギン、リシン、セリンと、ジヒドロキシエチルグリシン（Ｎ，Ｎ−ビス（２−ヒドロキシエチル）グリシン）、グリシンＮ，Ｎ’−１，２−エタンジルビス〔Ｎ−（カルボキシメチル）、グリシンＮ−〔２−〔ビス（カルボキシメチル）アミノ〕エチル〕−Ｎ−（２−ヒドロキシエチル）等のグリシン誘導体等が挙げられる。Ｗ又はＷ合金の配線又は電極のデポ洗浄性の観点から、グリシン、アラニン、アスパラギン酸、Ｎ，Ｎ−ビス（２−ヒドロキシエチル）グリシン、グリシンＮ，Ｎ’−１，２−エタンジルビス〔Ｎ−（カルボキシメチル）及びグリシンＮ−〔２−〔ビス（カルボキシメチル）アミノ〕エチル〕−Ｎ−（２−ヒドロキシエチル）が好ましい。
【００４６】
かかる（ｃ）分子中に窒素原子を有する化合物の洗浄剤組成物中における含有量は、０．０１〜２０重量％が好ましく、０．０５〜１０重量％がより好ましく、０．１〜５重量％が更に好ましい。該含有量は、Ｗ又はＷ合金の配線又は電極のデポ洗浄性の観点から、０．０１重量％以上が好ましく、また、相溶性の観点から、２０重量％以下であることが好ましい。
【００４７】
また、前記洗浄剤組成物は、（ｄ）有機溶剤を含有していてもよい。（ｄ）有機溶剤としては、式（Ｉ）：
Ｒ¹ ［（Ｘ）（ＡＯ）_k Ｒ² ］_m （Ｉ）
（式中、Ｒ¹ は水素原子又は炭素数１〜８の炭化水素基、Ｘは−Ｏ−基、−ＣＯＯ−基、−ＮＨ−基、又は−Ｎ（（ＡＯ）_n Ｈ）−基、ｋ及びｎは１〜２０、Ａは炭素数２又は３のアルキレン基、Ｒ² は水素原子又は炭素数１〜８の炭化水素基、ｍは１〜８を示す。）
で表されるアルキレンオキサイド化合物、アルコール類、エーテル類、カルボニル類、エステル類、フェノール類、含窒素化合物、含硫黄化合物等が挙げられる。（ｄ）有機溶剤の具体例は、新版溶剤ポケットブック（（株）オーム社、平成６年６月１０日発行）のデータ編３３１〜７６１頁に記載の化合物が挙げられる。
【００４８】
式（Ｉ）において、Ｒ¹ は、水素原子又は炭素数１〜６の炭化水素基が好ましく、Ｒ² は水素原子又は炭素数１〜４の炭化水素基が好ましく、水素原子又は炭素数１又は２の炭化水素基がより好ましく、ｍは１〜３が好ましく、１又は２がさらに好ましい。
【００４９】
式（Ｉ）で表されるアルキレンオキサイド化合物の具体例としては、エチレングリコールのメチルエーテル、エチルエーテル、プロピルエーテル、ブチルエーテル、ヘキシルエーテル、フェニルエーテル、ベンジルエーテル、ジメチルエーテル、ジエチルエーテル、ブチルメチルエーテル、エチルプロピルエーテル、ブチルエチルエーテル、ジプロピルエーテル、ジブチルエーテル等；それらに対応するジエチレングリコールアルキルエーテル、トリエチレングリコールアルキルエーテル等；テトラエチレングリコールのメチルエーテル、エチルエーテル、プロピルエーテル、ブチルエーテル、ヘキシルエーテル、フェニルエーテル、ベンジルエーテル、ジメチルエーテル、ジエチルエーテル等；それらに対応するペンタエチレングリコールアルキルエーテル、ヘキサエチレングリコールアルキルエーテル、プロピレングリコールアルキルエーテル、ジプロピレングリコールアルキルエーテル、トリプロピレングリコールアルキルエーテル等が挙げられる。
【００５０】
本発明で使用されるアルコール類としては、式(III) ：
Ｒ³ −（ＯＨ）_m (III)
（式中、Ｒ³ 及びｍは前記式（II）、式（Ｉ）の定義とそれぞれ同じ。）
で表される化合物が挙げられる。
【００５１】
エーテル類としては、式(IV)：
Ｒ³ −Ｏ−Ｒ³ (IV)
（式中、Ｒ³ は前記式（II）の定義と同じ。）
で表される化合物が挙げられる。
【００５２】
カルボニル類としては、式（Ｖ）：
【００５３】
【化１】

【００５４】
（式中、Ｒ³ は前記式（II）の定義と同じ。）
で表される化合物が挙げられる。
【００５５】
エステル類としては、式(VI)：
Ｒ³ −ＣＯＯＲ³ （VI）
（式中、Ｒ³ は前記式（II）の定義と同じ。）
で表される化合物が挙げられる。
【００５６】
フェノール類は式（VII)：
【００５７】
【化２】

【００５８】
（式中、Ｒ⁷ は炭素数１〜９の直鎖状、分岐鎖状若しくは環状の骨格からなる飽和又は不飽和炭化水素基であり、Ｒ⁷ の炭化水素基は１〜５個の酸素原子、窒素原子又は硫黄原子を有していてもよく、Ｒ⁷ の炭素原子に結合している水素原子は−ＯＨ基、−ＮＨ₂ 基、−ＳＨ基又は−ＮＯ₂ 基で置換されていてもよい。ｓは０〜５、ｔは１〜３を示す。）
で表される化合物を指す。
【００５９】
含窒素化合物は、分子量２００以下の窒素原子を含んでいる化合物であれば特に限定はない。含硫黄化合物は分子量２００以下の硫黄原子を含んでいる化合物であれば特に限定はない。
【００６０】
（ｄ）有機溶剤は、浸透性の観点から、式（Ｉ）で表されるアルキレンオキサイド化合物であるジエチレングリコールモノブチルエーテル及びジエチレングリコールモノヘキシルエーテル；アルコール類であるプロパノール、ブタノール及びペンタノール；エーテル類であるトリオキサン及びメチラール；カルボニル類であるアクロレイン及びメチルエチルケトン；エステル類であるアセト酢酸ニトリル及びギ酸エチル；フェノール類であるベンジルフェノール；含窒素化合物であるジメチルホルムアミド、ジメチルアセトアミド、Ｎ−メチル−２−ピロリドン及びジメチルイミダゾリジノン；含硫黄化合物であるジメチルスルホキサイド及びスルホランが好ましい。これらの（ｄ）有機溶剤は、単独で又は２種以上を混合して使用してもよい。
【００６１】
また、（ｄ）有機溶剤の融点は、デポ洗浄性確保及び作業性の観点から、６０℃以下が好ましく、３０℃以下がより好ましく、１０℃以下がさらに好ましい。
【００６２】
（ｄ）有機溶剤は、デポへの酸及び／又はその塩若しくは水の浸透を促進し、その結果としてデポ洗浄性を向上させる観点から、２５℃の水に０. ５重量％以上溶解するものが好ましく、４重量％以上溶解するものがより好ましく、7 重量％以上溶解するものが更に好ましい。
【００６３】
（ｄ）有機溶剤の洗浄剤組成物中における含有量は、優れたデポ洗浄性及び高い浸透力を得る観点から、０．１〜９０重量％が好ましく、０．５〜８０重量％がより好ましく、１〜５０重量％がさらに好ましい。
【００６４】
なお、前記洗浄剤組成物中の（ａ）〜（ｄ）成分の含有量は、該組成物製造時の含有量、及び使用時の含有量のいずれであっても良い。通常、濃縮液として組成物は製造され、これを使用時に希釈して用いる場合が多い。
【００６５】
以上の成分を含有する洗浄剤組成物のｐＨは、６以上１１以下であることが必要とされる。本発明においては、洗浄剤組成物のｐＨが６以上１１以下であることにも一つの大きな特徴があり、ｐＨを６以上１１以下に調節することにより、デポ洗浄性が十分で、しかも金属材料に対する腐食が抑制でき、その結果、半導体素子の生産性向上や品質向上に寄与できるという優れた効果が発現される。従って、洗浄剤組成物が、前記（ａ）〜（ｃ）成分又はさらに（ｄ）成分を含有していても、そのｐＨが６未満では、優れたＷ又はＷ合金の配線又は電極のデポ洗浄性及び金属材料に対する腐食防止性は得られない。該ｐＨの下限は、６．５以上が好ましく、７．０以上がより好ましく、７．５以上がさらに好ましく、８．０以上が特に好ましい。またｐＨの上限は、１０以下が好ましく、９．５以下がより好ましく、９．２以下がさらに好ましく、８．７以下が特に好ましい。ｐＨとしては、好ましくは６．５〜１０、より好ましくは７．０〜９．５、さらに好ましくは７．５〜９．２、特に好ましくは８．０〜９．２、最も好ましくは８．０〜８．７である。
【００６６】
また、任意成分として、非イオン界面活性剤、アニオン界面活性剤等の界面活性剤を適宜配合することができる。
【００６７】
【実施例】
実施例１〜１５及び比較例１〜５
（洗浄特性評価）
▲１▼タングステン（Ｗ）配線パターン
７００μm 厚のＳｉ／ＳｉＯ₂ ／ポリＳｉ／ＷＮ／Ｗ／Ｓｉ₃ Ｎ₄ 〔基板／３／１００／１０／５０／５０（ｎｍ）〕の積層基板に対してノボラック樹脂材質のポジ型フォトレジストを用いてパターン化し、プラズマエッチング処理を行った。エッチング処理ガスとしてはフッ素系、塩素系のガスを順次用いた。エッチング後、フォトレジストを酸素プラズマ灰化処理により除去した。
【００６８】
▲２▼アルミニウム（Ａｌ）配線パターン
７００μm 厚のＳｉ／Ｔｉ／ＴｉＮ／Ａｌ／ＴｉＮ〔基板／１００／１００／４００／１００（ｎｍ）〕の積層基板に対し、ノボラック樹脂材質のポジ型フォトレジストを用いてパターン化し、プラズマエッチング処理を行った。エッチング処理ガスとしては塩素系、フッ素系のガスを順次用いた。エッチングの後、フォトレジストを酸素プラズマ灰化処理により除去した。
【００６９】
▲３▼銅（Ｃｕ）配線上のホールパターン
７００μm 厚のＳｉ／Ｃｕ／Ｓｉ₃ Ｎ₄ ／ＳｉＯ₂ 〔基板／４００／５０／３００（ｎｍ）〕の積層基板に対してノボラック樹脂材質のポジ型フォトレジストを用いてパターン化し、プラズマエッチング処理を行った。エッチング処理ガスとしては塩素系、フッ素系のガスを順次用いた。エッチングの後、フォトレジストを酸素プラズマ灰化処理により除去した。
【００７０】
表１、２に記載の実施例１〜１５、比較例１〜５で得られた洗浄剤組成物を用いて、基板の洗浄を行なった。尚、実施例１〜９、１１及び比較例１〜５では基板を洗浄剤組成物中に３０℃、１０分間浸漬して洗浄を行った。実施例１０では処理すべき基板上に洗浄剤組成物を３０℃、５分間気中でスプレーして洗浄を行った。実施例１２、１３では基板を洗浄剤組成物中にそれぞれ６０℃、５０℃で１０分間浸漬して洗浄を行った。実施例１４、１５では基板を洗浄剤組成物中に３０℃で１０分間浸漬して洗浄を行なった。洗浄後、基板を水でリンスした。乾燥後に電界放射型走査電子顕微鏡で基板の表面を５万倍に拡大して、形成した配線又はホールパターンを１００個観察し、そのデポ洗浄性と配線の腐食性を下記基準により評価した。その結果を表１、２に示す。
【００７１】
〔デポ洗浄性〕
デポ洗浄率＝（デポが完全に除去されたパターンの個数／100 ）×100
評価基準
Ａ：９５％以上１００％以下、Ｂ：９０％以上９５％未満、Ｃ：８０％以上９０％未満、Ｄ：０％以上８０％未満
【００７２】
〔配線の腐食性〕
腐食率＝（しみ又は孔食が認められたレジストパターンの個数）／100 ）×100
評価基準
Ａ：０％以上２．５％未満、Ｂ：２．５％以上５％未満、Ｃ：５％以上１０％未満、Ｄ：１０％以上１００％以下
なお、上記の評価において、全ての評価がＡ又はＢのものを合格品とする。
【００７３】
【表１】

【００７４】
【表２】

【００７５】
表１、２の結果より、実施例１〜１５で得られた洗浄剤組成物は、いずれも比較例１〜５で得られた洗浄剤組成物に比べて、各種配線に存在するデポの洗浄性に優れ、かつ腐食も発生しにくいものであることがわかる。
【００７６】
実施例１６
ｎ型シリコン基板上に素子分離酸化膜、多結晶Ｓｉ膜、ＷＮ膜、Ｗ膜を順次堆積させて、ＷＮ／Ｗ複合膜を形成させる。該ＷＮ／Ｗ複合膜上にレジストパターンをマスクとする通常のフォトエッチング工程により、エッチングとアッシングを行い、次いで、実施例１〜１５いずれかの洗浄剤組成物を用いて前記基板を気中シャワー（３０℃、５分）し、エッチング残渣及びアッシング残渣（以下、デポという）を洗浄する。その後、前記の方法を用いて配線を観察する。
【００７７】
次いで、イオン注入でｐ型とｎ型のＬＤＤ領域、ｐ型とｎ型のソースとドレイン領域を設けた後、その全面に層間絶縁膜、ＳｉＯ₂ を積層させ、化学機械研磨（ＣＭＰ）法を用いて表面を平坦化する。
次いで、ｐ型のソースとドメイン領域とｎ型のソースとドレイン領域に達するコンタクトホールを形成し、Ｗを埋め込みＷプラグを形成する。
【００７８】
次いで、その全面にＴｉＮ膜、Ａｌ膜を順次堆積させて、レジストパターンをマスクとする通常のフォトエッチングを行う。その後、実施例１〜１５いずれかの洗浄剤組成物を用いて前記基板を気中シャワー（３０℃、５分）し、エッチング残渣及びアッシング残渣（以下、デポという）を洗浄する。その後、前記の方法を用いて配線を観察する。
上記２つの時点において、基板上のＡｌ配線及びＷ電極には、いずれもデポが極めて少なく、かつ腐食も発生していないことが観察される。
【００７９】
【発明の効果】
本発明の洗浄方法を用いることで、高エネルギー処理を受けて変質したデポでも容易にかつ短時間で洗浄することができ、しかもアルミニウム、タングステン、これらの合金等の配線材料に対する腐食が抑制できる。その結果、半導体素子やＬＣＤ等の生産性向上に大きく寄与できる。
また、本発明の洗浄方法を、半導体の製造工程中の複数のデポ洗浄工程において使用することで、洗浄装置の設置スペースや洗浄液の保管スペースを大幅に低減することができるという優れた効果が奏される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for cleaning a semiconductor substrate including at least tungsten or tungsten alloy wiring or electrodes and aluminum or aluminum alloy wiring. More specifically, a step of forming a semiconductor element on a semiconductor substrate such as a silicon wafer, in particular, tungsten or tungsten alloy wiring or electrodes and aluminum or aluminum alloy wiring were dry-etched and ashed using a reactive gas. The present invention relates to a method for cleaning a semiconductor substrate after ashing used in a step of removing so-called deposits such as a residue, that is, a resist residue and an etching residue. In particular, it is used for a cleaning process of a deposit after dry etching and ashing in a tungsten or tungsten alloy wiring or gate electrode manufacturing process (front-end process), a bit line forming process, an aluminum or aluminum alloy wiring forming process, etc. The present invention relates to a method for cleaning a semiconductor substrate.
[0002]
[Prior art]
In the manufacture of semiconductor devices and LCDs, after forming a conductive film or insulating film by PVD (physical vapor deposition) or CVD (chemical vapor deposition), a predetermined resist pattern is formed on the thin film by lithography. Then, using this as a mask, a step of selectively etching and removing the lower layer thin film is performed. Thereafter, the resist is removed by an ashing process, but a deposit mainly composed of an inorganic compound remains. However, in the conventional cleaning method, when removing the deposit, the cleaning liquid must be changed several times according to the type of metal such as tungsten, aluminum, and alloys thereof, which is extremely efficient. It was bad. In addition, high temperature cleaning is necessary to exert the cleaning performance of the drug.
[0003]
Furthermore, the clean room used for the cleaning process needs to keep the temperature and humidity constant while removing dust and bacteria in the air targeting 0.5 to 0.1 microns. The larger the (size), the higher the costs such as construction costs and capital investment costs. Therefore, in recent years, from the viewpoint of cost reduction, it is indispensable to save space in the clean room, and the cleaning apparatus installed in the clean room is also required to be compact.
[0004]
[Problems to be solved by the invention]
The present invention can be used in common for at least tungsten or tungsten alloy wiring or electrodes and aluminum or aluminum alloy wiring, has excellent deposit cleaning properties, and various kinds of metal wiring and metal thin films on semiconductor elements and LCDs. It is an object of the present invention to provide a low-temperature cleaning method for a semiconductor substrate that is also excellent in the effect of preventing corrosion of members. It is another object of the present invention to provide a method for cleaning a semiconductor substrate that can reduce the installation space for the cleaning device and the storage space for the cleaning liquid.
[0005]
[Means for Solving the Problems]
The inventors of the present invention have investigated in detail the wiring of tungsten or a tungsten alloy (hereinafter also referred to as W or W alloy) and the deposit cleaning property of the electrode. As a result, the wiring of aluminum or aluminum alloy (hereinafter also referred to as Al or Al alloy) is used. Unlike the case of, it was found for the first time that the detergency of the deposit increased as the pH increased. In addition, in the case of Al or Al alloy wiring, it has also been found that the deposit (aluminum oxide) is dissolved even though it is higher than the neutral region. Furthermore, in recent years, since the wiring width has become narrower to 0.13 to 0.18 μm, the etching area has become smaller and the deposit has become thinner, so that the cleaning tends to be easier. Therefore, by considering these facts and conducting intensive research, the present invention shows an excellent cleaning effect in common with respect to W or W alloy wiring and electrode deposits and Al or Al alloy wiring deposits. It came to be completed.
[0006]
  That is, the gist of the present invention is that (a) the acid dissociation index pKa of the nth stage of the n-valent basic acid_nIt comprises an acid and / or salt thereof (25 ° C.) of 3 or more and 11 or less, (b) water, and (c) a chelating agent containing a nitrogen atom in the molecule, and has a pH of 6 or more and 11 or less. A semiconductor substrate comprising at least (A) a tungsten or tungsten alloy wiring or electrode and (B) an aluminum or aluminum alloy wiring is cleaned at 15 to 60 ° C. using the cleaning composition.For removing residues on the semiconductor substrate after etching and ashingThe present invention relates to a method for cleaning a semiconductor substrate.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
As described above, in the cleaning method of the present invention, (a) the acid dissociation index pKa of the n-th basic acid in the n-th stage_nIt contains an acid and / or salt thereof (25 ° C.) of 3 or more and 11 or less, (b) water, and (c) a chelating agent containing a nitrogen atom in the molecule, and has a pH of 6 or more and 11 or less. There is one major feature in using the cleaning composition.
[0008]
By using such a cleaning method for cleaning a semiconductor substrate, at least (A) a tungsten or tungsten alloy (hereinafter also referred to as W or W alloy) wiring or electrode and (B) aluminum or an aluminum alloy (hereinafter referred to as Al or Al). The effect is that the deposit attached to the wiring of the Al alloy) can be efficiently removed while suppressing the corrosion of various members such as the metal wiring and the metal thin film on the semiconductor element or LCD.
[0009]
Further, the cleaning method of the present invention is for cleaning a semiconductor substrate having at least a W or W alloy wiring or electrode and an Al or Al alloy wiring by using the cleaning composition. Specific examples of such cleaning methods include methods such as immersion, submerged shower, and air shower.
[0010]
As the dipping method, one or more wafers to be processed are set in a jig and immersed in the cleaning composition, and the jig is swung or mechanical force such as ultrasonic waves is applied to the cleaning liquid. A method of washing while giving Examples of the submerged shower method include a method of performing a cleaning process while applying a jet to the wafer to be processed in the liquid of the cleaning composition. Moreover, as an air shower method, the method of spraying the said cleaning composition on the wafer which should be processed in air (shower) and performing the cleaning process is mentioned. In addition, as a cleaning apparatus used for these cleaning methods, a generally known apparatus can be used.
[0011]
In addition, the cleaning method of the present invention has another great feature in that the cleaning temperature is low. The cleaning temperature is 15 to 60 ° C. from the viewpoint of preventing corrosion of metal wiring, and has good cleaning properties and utility. 20-50 degreeC is preferable from a viewpoint of making cost reduction compatible, and 25-40 degreeC is especially preferable.
[0012]
The washing time is preferably 1 to 30 minutes, more preferably 5 to 20 minutes, and particularly preferably 5 to 15 minutes.
[0013]
In addition, the said washing | cleaning method and conditions can be changed according to the kind of washing | cleaning material.
[0014]
Further, after these cleaning steps, it is preferable to remove the cleaning agent composition remaining on the wafer by rinsing with a solvent such as water or isopropyl alcohol.
[0015]
By using the cleaning method of the present invention as described above, it is possible to easily clean deposits deposited on members such as inorganic elements such as semiconductor elements and LCDs without damaging those members.
[0016]
In the present invention, “(A) a semiconductor substrate comprising at least a W or W alloy wiring or electrode and (B) an Al or Al alloy wiring” means that the semiconductor substrate to be cleaned is at least (A) W or It means that a wiring or electrode having a W alloy and (B) a wiring having Al or an Al alloy are provided. The semiconductor substrate may further include other metal members such as copper or copper alloy.
[0017]
Therefore, the cleaning method of the present invention is a process for forming a semiconductor element on a semiconductor substrate such as a silicon wafer, particularly, dry etching and ashing using a reactive gas for a wiring or electrode having W or W alloy and Al or Al alloy. Steps for removing so-called deposits such as residues after etching, that is, resist residues and etching residues, in particular, gate electrode manufacturing step (front end process) having W or W alloy, bit line forming step, Al or Al alloy It is preferably used for a wiring forming process having a dry etching process and a cleaning process for a deposit after ashing.
[0018]
In particular, in the semiconductor manufacturing process, W or W alloy wiring, W or W alloy electrodes, and Al or Al alloy wiring are manufactured by dividing the processes in a desired order as appropriate. Accordingly, the cleaning method of the present invention can easily clean deposits deposited on members such as semiconductor elements and LCDs without damaging those members, so that in the manufacturing process of semiconductor elements and LCDs, etc. It can be suitably used for a plurality of depot cleaning steps.
[0019]
Further, as described above, by using the cleaning method of the present invention in a plurality of deposition cleaning steps in the semiconductor manufacturing process, it is possible to greatly reduce the installation space for the cleaning device and the storage space for the cleaning liquid. The effect is expressed.
[0020]
The cleaning composition used in the present invention will be described below.
The acid (a) used in the present invention is an acid dissociation index pKa of the nth stage of an n-valent basic acid._n(25 degreeC) is 3 or more and 11 or less. pKa_nThe temperature (25 ° C.) is preferably 5 or more and 11 or less from the viewpoint of achieving both depot cleaning properties and corrosion resistance of tungsten and aluminum. PKa_n(25 ° C.) refers to that obtained by the following method.
[0021]
(PKa_nDescription)
n-valent acid (in general formula H_nWhen A) is dissolved in water, it dissociates as follows.
[0022]
[Expression 1]

[0023]
At this time, the dissociation constant Ka of the first stage, the second stage, and the n-th stage₁, Ka₂, Ka_nIs defined as follows:
Ka₁= [H_n-1A^-] [H⁺] / [H_nA]
Ka₂= [H_n-2A^2-] [H⁺] / [H_n-1A^-]
Ka_n= [A^n-] [H⁺] / [HA^(n-1)-]
[0024]
Therefore, Ka_nIs the logarithm of the reciprocal of i._nIt is expressed as
pKa_n= Log (1 / Ka_n) =-LogKa_n
[0025]
In the present invention, pKa_nThe chemical handbook revised 4th edition, basic edition II (edited by the Chemical Society of Japan), page II-317, Table 10 · 18, acid dissociation constant of inorganic compounds in aqueous solution (25 ° C), II-317-321 pages, Table 10・ 19 Acid dissociation constant (25 ° C.) of organic compounds, given by RIKEN Dictionary 4th edition (Iwanami Shoten), and those not mentioned above are described in Ion Equilibrium (Chemical Doujin), pages 53 and 66-68. It can be determined based on the usual experimental method described.
[0026]
Examples of the component (a) include inorganic acids such as oxo acid, hydrogen acid, and peroxo acid; carboxylic acid, thiocarboxylic acid, peracid, mercaptan, sulfonic acid, phosphatidic acid, dithiocarboxylic acid, sulfinic acid, sulfenic acid, and phosphone. Organic acids such as acid, phosphinic acid, carbonic acid ester, sulfuric acid ester, phosphoric acid ester and boric acid ester are listed.
[0027]
Specific examples of the inorganic acid include oxo acids such as carbonic acid, bicarbonate, boric acid, iodic acid, nitric acid, sulfuric acid, hypobromous acid, hypochlorous acid, chlorous acid, perchloric acid, nitrous acid, and sulfurous acid; Examples thereof include hydrobromic acid such as hydrobromic acid, hydrochloric acid, hydrofluoric acid, hydroiodic acid and hydrosulfuric acid; and peroxoacids such as peroxonitric acid, peroxosulfuric acid and peroxodisulfuric acid.
[0028]
Among organic acids, carboxylic acids are preferred from the viewpoint of depot cleaning and prevention of corrosion on metal materials. Examples of the carboxylic acid include linear saturated monocarboxylic acid, linear unsaturated monocarboxylic acid, branched saturated monocarboxylic acid, branched unsaturated monocarboxylic acid, saturated polycarboxylic acid, unsaturated polycarboxylic acid, hydroxycarboxylic acid Examples include acids, alkoxycarboxylic acids, carboxylic acids having an aromatic ring, and carboxylic acids having an alicyclic ring.
[0029]
As the carboxylic acid, the formula (II):
B-[(R^Three)_p-(COOH)_q]_r                    (II)
(Wherein R^ThreeIs a hydrogen atom, a saturated or unsaturated hydrocarbon group composed of a linear, branched or cyclic skeleton having 1 to 40 carbon atoms, and R^ThreeThe hydrocarbon group may have 1 to 5 oxygen atoms or sulfur atoms, and R^ThreeThe hydrogen atom bonded to the carbon atom of may be substituted with —OH group or —SH group, and q number of —COOH groups may be R^ThreeMay be bonded to one or more of the same carbon atoms, p is 0 or 1, q is an integer of 1 to 40, r is an integer of 1 to 3, B is absent or —O— group, -CO- group or -S- group is shown. )
The carboxylic acid represented by these is preferable.
[0030]
In the formula (II), from the viewpoint of depot cleaning and corrosion prevention for metal materials, R^ThreeIs a hydrogen atom, a linear saturated hydrocarbon group having 1 to 18 carbon atoms, a branched saturated hydrocarbon group having 3 to 18 carbon atoms, a linear unsaturated hydrocarbon group having 2 to 18 carbon atoms, A branched unsaturated hydrocarbon group having 3 to 18 carbon atoms, a saturated or unsaturated hydrocarbon group having an alicyclic ring having 3 to 18 carbon atoms, and a saturated or unsaturated hydrocarbon having an aromatic ring having 6 to 18 carbon atoms Groups are preferred. Furthermore, R^ThreeIs a linear saturated hydrocarbon group having 1 to 12 carbon atoms, a branched saturated hydrocarbon group having 3 to 12 carbon atoms, a linear unsaturated hydrocarbon group having 2 to 12 carbon atoms, 3 carbon atoms -12 branched unsaturated hydrocarbon groups, saturated or unsaturated hydrocarbon groups having an alicyclic ring having 3 to 12 carbon atoms, and saturated or unsaturated hydrocarbon groups having an aromatic ring having 6 to 12 carbon atoms. preferable. In particular, R^ThreeIs a linear saturated hydrocarbon group having 1 to 6 carbon atoms, a branched saturated hydrocarbon group having 3 to 6 carbon atoms, a linear unsaturated hydrocarbon group having 2 to 6 carbon atoms, 3 carbon atoms -6 branched branched unsaturated hydrocarbon groups, saturated or unsaturated hydrocarbon groups having 3 to 6 carbon atoms alicyclic rings, saturated or unsaturated hydrocarbon groups having 6 to 8 carbon atoms aromatic rings are the most. preferable. R^ThreeIn the case where each hydrocarbon group has an oxygen atom or a sulfur atom, 1 to 2 atoms are more preferred.
[0031]
In the formula (II), q is preferably an integer of 1 to 18, more preferably an integer of 1 to 12, still more preferably an integer of 1 to 6, from the viewpoint of depot cleaning properties and prevention of corrosion on metal materials. An integer of ˜2 is particularly preferred.
[0032]
Specific examples of preferred carboxylic acids include linear saturated monocarboxylic acids having 1 to 18 carbon atoms such as formic acid, acetic acid, propionic acid; acrylic acid, crotonic acid, vinyl acetic acid, 4-pentenoic acid, 6-heptenoic acid, Linear unsaturated monocarboxylic acids such as 2-octenoic acid, undecylenic acid, oleic acid; isobutyric acid, isovaleric acid, pivalic acid, 2-methylbutyric acid, 2-methylvaleric acid, 2,2-dimethylbutyric acid, 2-ethyl Butyric acid, tert-butylbutyric acid, 2,2-dimethylpentanoic acid, 2-ethylpentanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, 2,4-dimethylhexanoic acid, 2-methylheptanoic acid, 2-propyl Pentanoic acid, 3,5,5-trimethylhexanoic acid, 2-methyloctanoic acid, 2-ethylheptanoic acid, 2-ethyl-2,3,3-trimethylbutyric acid, 2, 2, 4 Branched-chain saturated monocarboxylic acids such as 1,2-tetramethylpentanoic acid and 2,2-diisopropylpropionic acid; methacrylic acid, tiglic acid, 3,3-dimethylacrylic acid, 2,2-dimethyl-4-pentenoic acid, 2 -Branched unsaturated monocarboxylic acids such as ethyl-2-hexenoic acid and citronelllic acid; oxalic acid, malonic acid, methylmalonic acid, ethylmalonic acid, dimethylmalonic acid, succinic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid Acid, glutaric acid, adipic acid, 3-methyladipic acid, sebacic acid, hexadecanedioic acid, 1,2,3-propanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, polyacrylic acid, polymaleic acid Saturated polycarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, cis-aconitic acid, trans-aconitic acid Unsaturated polyvalent carboxylic acids; hydroxycarboxylic acids such as lactic acid, gluconic acid, tartaric acid, malic acid and citric acid; alkoxycarboxylic acids such as methoxyacetic acid and ethoxyacetic acid; benzoic acid, terephthalic acid, trimellitic acid, naphthoic acid, etc. And carboxylic acids having an alicyclic ring such as cyclohexanecarboxylic acid, cyclohexanepropionic acid, cyclohexanebutyric acid, and cyclopentanecarboxylic acid.
[0033]
Among these, linear saturated monocarboxylic acids having 1 to 6 carbon atoms such as formic acid, acetic acid and propionic acid; saturated polycarboxylic acids such as oxalic acid, malonic acid and succinic acid; lactic acid, gluconic acid, tartaric acid, More preferred are hydroxycarboxylic acids such as malic acid and citric acid; alkoxycarboxylic acids such as methoxyacetic acid and ethoxyacetic acid. In particular, formic acid, acetic acid, oxalic acid, malonic acid, succinic acid, lactic acid, gluconic acid, tartaric acid, malic acid and citric acid are preferred.
[0034]
The molecular weight of the carboxylic acid is not particularly limited, but is preferably 46 to 400, more preferably 46 to 200, from the viewpoints of depot cleaning properties and prevention of corrosion on metal materials.
[0035]
Examples of the acid salt include a salt of an acid with a basic organic compound or a basic inorganic compound. Examples of basic organic compounds include primary amines, secondary amines, tertiary amines, imines, alkanolamines, amides, basic heterocyclic compounds, and quaternary ammonium hydroxides. Examples of the basic inorganic compound include ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide and the like. Among these, from the viewpoint of avoiding mixing of metal ions, ammonium salts of acids and salts of acids and basic organic compounds are preferable. In particular, an ammonium salt is particularly preferable because a deposit generated in the wiring or electrode of W or W alloy is tungsten oxide, so that it becomes water-soluble by forming an ammonium salt of tungsten and easily peels off. These acid salts may be used alone or in admixture of two or more.
[0036]
Moreover, you may use the said acid and / or its salt individually or in mixture of 2 or more types.
[0037]
The content of the (a) acid and / or salt thereof in the cleaning composition is preferably 0.01 to 65% by weight from the viewpoint of obtaining excellent depot cleaning properties, and prevents the depot cleaning properties and corrosion of metal materials. In view of the above, 0.05 to 55% by weight is more preferable, 0.1 to 35% by weight is more preferable, and 0.5 to 20% by weight is particularly preferable.
[0038]
The water (b) used in the present invention is an ionic substance or particle such as ion-exchanged water, pure water or ultrapure water, considering that the cleaning composition is used in the field of manufacturing semiconductor devices and LCDs. What reduced as much as possible etc. is preferable.
[0039]
(B) The content of water in the cleaning composition is preferably 30 to 99% by weight from the viewpoint of improving the depot cleaning properties. In the present invention, by adjusting the water content to such a range, it is possible to obtain a cleaning composition having excellent depot cleaning properties and a corrosion preventing effect on metal materials. Further, the content of water is more preferably 40 to 97% by weight, and still more preferably 60 to 95% by weight, from the viewpoint of depot cleaning properties and prevention of corrosion on the metal material.
[0040]
(C) A chelating agent containing a nitrogen atom in the molecule refers to a compound having a molecular weight of 40 to 3000, including a primary to tertiary amino group and / or a quaternary ammonium salt in the molecule. The chelating agent refers to a metal sequestering agent that generates a water-soluble metal chelate, and specifically refers to a multidentate ligand that coordinates with a metal ion and wraps around the metal ion. An electron donor having the ability to coordinate bond to a metal ion is called a ligand, and one having two, three, and four electron donating groups per molecule is bidentate, tridentate, It is called a bidentate ligand, and a bidentate ligand or more is collectively called a multidentate ligand. (C) As an example of a chelating agent containing a nitrogen atom in its molecule, “Metal Chelate (III)” (Edited by Keihei Ueno, Takeichi Sakaguchi, published by Nanedo, 1st edition, 1967) “Stability Constant Table” And at least one selected from the group consisting of amines and derivatives thereof, aminopolycarboxylic acids and amino acids described on pages 15-55.
[0041]
As amines and their derivatives, the formula:
R^FourR^FiveR⁶N
(Wherein R^Four, R^FiveAnd R⁶Is a hydrogen atom, a saturated or unsaturated hydrocarbon group composed of a linear, branched or cyclic skeleton having 1 to 20 carbon atoms, and R^Four, R^FiveAnd R⁶The hydrocarbon group may have 1 to 5 oxygen atoms, nitrogen atoms or sulfur atoms, and R^Four, R^FiveAnd R⁶The hydrogen atom bonded to the carbon atom of —OH group, —NH₂Group or -SH₂It may be substituted with a group. R^Four, R^FiveAnd R⁶May be the same or different. )
The compound represented by these is mentioned.
[0042]
Specific examples thereof include ethylenediamine, N-methylethylenediamine, N-ethylethylenediamine, N- (2-hydroxyethyl) ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, triethylenediamine, imidazole, histamine and the like. .
[0043]
The aminopolycarboxylic acid has the formula:
R^FourNY₂, NY_Three, R^FourYN-CH₂CH₂-NYR^Five, R^FourYN-CH₂CH₂-NY₂, Y₂N- (CH₂)_u-NY₂
(Wherein R^FourAnd R^FiveIs the same as above, Y is —CH₂COOH or -CH₂-CH₂COOH is shown. u represents an integer of 1 to 10. )
The compound represented by these is mentioned.
[0044]
Specific examples thereof include R^FourNY₂Types of iminodiacetic acid, hydroxyethyliminodiacetic acid; NY_ThreeType nitrilotriacetic acid; R^FourYN-CH₂CH₂-NYR^FiveType N, N'-ethylenediaminediacetic acid; R^FourYN-CH₂CH₂-NY₂N'-hydroxyethyl-N, N, N'-triacetic acid in the form; Y₂N- (CH₂)_u-NY₂Examples thereof include ethylenediaminetetraacetic acid. Among these, N, N'-ethylenediaminediacetic acid, N'-hydroxyethyl-N, N, N'-triacetic acid and ethylenediaminetetraacetic acid are preferable from the viewpoint of the depot cleaning property of the wiring or electrode having W or W alloy.
[0045]
Amino acids have a carboxyl group (COOH) and an amino group (NH₂). Specific examples thereof include glycine, alanine, β-alanine, sarcosine, aspartic acid, asparagine, lysine, serine, dihydroxyethyl glycine (N, N-bis (2-hydroxyethyl) glycine), glycine N, N′-. Examples thereof include glycine derivatives such as 1,2-ethanedibis [N- (carboxymethyl), glycine N- [2- [bis (carboxymethyl) amino] ethyl] -N- (2-hydroxyethyl). From the viewpoint of depot cleaning properties of W or W alloy wiring or electrodes, glycine, alanine, aspartic acid, N, N-bis (2-hydroxyethyl) glycine, glycine N, N′-1,2-ethanedibis [N— (Carboxymethyl) and glycine N- [2- [bis (carboxymethyl) amino] ethyl] -N- (2-hydroxyethyl) are preferred.
[0046]
The content of the compound (c) having a nitrogen atom in the molecule in the detergent composition is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, and 0.1 to 5% by weight. % Is more preferable. The content is preferably 0.01% by weight or more from the viewpoint of depot cleaning properties of the W or W alloy wiring or electrode, and is preferably 20% by weight or less from the viewpoint of compatibility.
[0047]
In addition, the cleaning composition may contain (d) an organic solvent. (D) As the organic solvent, the formula (I):
R¹[(X) (AO)_kR²]_m          (I)
(Wherein R¹Is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, X is an —O— group, —COO— group, —NH— group, or —N ((AO))_nH) -group, k and n are 1 to 20, A is an alkylene group having 2 or 3 carbon atoms, R²Represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and m represents 1 to 8. )
And an alkylene oxide compound represented by the formula: alcohols, ethers, carbonyls, esters, phenols, nitrogen-containing compounds, sulfur-containing compounds, and the like. (D) Specific examples of the organic solvent include compounds described in Data edition pages 331 to 761 of the new edition solvent pocket book (Ohm Co., Ltd., issued on June 10, 1994).
[0048]
In formula (I), R¹Is preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, R²Is preferably a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 or 2 carbon atoms, m is preferably 1 to 3, and more preferably 1 or 2.
[0049]
Specific examples of the alkylene oxide compound represented by the formula (I) include ethylene glycol methyl ether, ethyl ether, propyl ether, butyl ether, hexyl ether, phenyl ether, benzyl ether, dimethyl ether, diethyl ether, butyl methyl ether, ethyl Propyl ether, butyl ethyl ether, dipropyl ether, dibutyl ether, etc .; corresponding diethylene glycol alkyl ether, triethylene glycol alkyl ether, etc .; tetraethylene glycol methyl ether, ethyl ether, propyl ether, butyl ether, hexyl ether, phenyl ether , Benzyl ether, dimethyl ether, diethyl ether, etc .; corresponding pentaethylene glycol Ruki ether, hexaethylene glycol alkyl ethers, propylene glycol alkyl ether, dipropylene glycol alkyl ether, tripropylene glycol alkyl ether, and the like.
[0050]
Examples of alcohols used in the present invention include formula (III):
R^Three-(OH)_m         (III)
(Wherein R^ThreeAnd m are the same as defined in formula (II) and formula (I), respectively. )
The compound represented by these is mentioned.
[0051]
Examples of ethers include formula (IV):
R^Three-O-R^Three          (IV)
(Wherein R^ThreeIs the same as defined in formula (II) above. )
The compound represented by these is mentioned.
[0052]
As carbonyls, the formula (V):
[0053]
[Chemical 1]

[0054]
(Wherein R^ThreeIs the same as defined in formula (II) above. )
The compound represented by these is mentioned.
[0055]
Esters include those of formula (VI):
R^Three-COOR^Three        (VI)
(Wherein R^ThreeIs the same as defined in formula (II) above. )
The compound represented by these is mentioned.
[0056]
Phenols have the formula (VII):
[0057]
[Chemical 2]

[0058]
(Wherein R⁷Is a saturated or unsaturated hydrocarbon group having a linear, branched or cyclic skeleton having 1 to 9 carbon atoms, and R⁷The hydrocarbon group may have 1 to 5 oxygen atoms, nitrogen atoms or sulfur atoms, and R⁷The hydrogen atom bonded to the carbon atom of —OH group, —NH₂Group, -SH group or -NO₂It may be substituted with a group. s shows 0-5, t shows 1-3. )
The compound represented by these is pointed out.
[0059]
The nitrogen-containing compound is not particularly limited as long as it is a compound containing a nitrogen atom having a molecular weight of 200 or less. The sulfur-containing compound is not particularly limited as long as it is a compound containing a sulfur atom having a molecular weight of 200 or less.
[0060]
(D) From the viewpoint of permeability, the organic solvent is diethylene glycol monobutyl ether and diethylene glycol monohexyl ether which are alkylene oxide compounds represented by the formula (I); propanol, butanol and pentanol which are alcohols; ethers Trioxane and methylal; carbonyls acrolein and methyl ethyl ketone; esters acetoacetonitrile and ethyl formate; phenols benzylphenol; nitrogen-containing compounds dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone and dimethyl Imidazolidinone; sulfur-containing compounds such as dimethyl sulfoxide and sulfolane are preferred. These (d) organic solvents may be used alone or in admixture of two or more.
[0061]
In addition, (d) the melting point of the organic solvent is preferably 60 ° C. or lower, more preferably 30 ° C. or lower, and even more preferably 10 ° C. or lower, from the viewpoint of ensuring depot cleaning properties and workability.
[0062]
(D) The organic solvent dissolves 0.5% by weight or more in water at 25 ° C. from the viewpoint of promoting the penetration of the acid and / or salt or water thereof into the depot and, as a result, improving the depot washability. It is preferable to dissolve 4% by weight or more, and more preferable to dissolve 7% by weight or more.
[0063]
(D) The content of the organic solvent in the cleaning composition is preferably 0.1 to 90% by weight, more preferably 0.5 to 80% by weight, from the viewpoint of obtaining excellent depot cleaning properties and high penetrating power. 1 to 50% by weight is more preferable.
[0064]
In addition, content of (a)-(d) component in the said cleaning composition may be any of content at the time of this composition manufacture, and content at the time of use. Usually, the composition is produced as a concentrated liquid, and it is often used after being diluted at the time of use.
[0065]
The pH of the cleaning composition containing the above components is required to be 6 or more and 11 or less. In the present invention, there is another great feature that the pH of the cleaning composition is 6 or more and 11 or less. By adjusting the pH to 6 or more and 11 or less, the depot cleaning property is sufficient, and the metal material. As a result, it is possible to suppress the corrosion of the semiconductor element, and as a result, it is possible to contribute to improving the productivity and quality of the semiconductor element. Therefore, even if the cleaning composition contains the above components (a) to (c) or further the component (d), if the pH is less than 6, excellent W or W alloy wiring or electrode depot cleaning And corrosion resistance to metal materials cannot be obtained. The lower limit of the pH is preferably 6.5 or more, more preferably 7.0 or more, further preferably 7.5 or more, and particularly preferably 8.0 or more. Further, the upper limit of the pH is preferably 10 or less, more preferably 9.5 or less, further preferably 9.2 or less, and particularly preferably 8.7 or less. The pH is preferably 6.5 to 10, more preferably 7.0 to 9.5, still more preferably 7.5 to 9.2, particularly preferably 8.0 to 9.2, and most preferably 8. 0-8.7.
[0066]
Moreover, surfactants, such as a nonionic surfactant and an anionic surfactant, can be suitably mix | blended as an arbitrary component.
[0067]
【Example】
Examples 1-15 and Comparative Examples 1-5
(Evaluation of cleaning characteristics)
(1) Tungsten (W) wiring pattern
700 μm thick Si / SiO₂/ Poly Si / WN / W / Si_ThreeN_FourA laminated substrate of [substrate / 3/100/10/50/50 (nm)] was patterned using a positive photoresist made of a novolac resin material and subjected to plasma etching. Fluorine-based and chlorine-based gases were sequentially used as the etching treatment gas. After the etching, the photoresist was removed by an oxygen plasma ashing process.
[0068]
(2) Aluminum (Al) wiring pattern
A 700 μm-thick Si / Ti / TiN / Al / TiN [substrate / 100/100/400/100 (nm)] laminated substrate is patterned using a novolac resin positive photoresist and subjected to a plasma etching process. went. Chlorine-based and fluorine-based gases were sequentially used as the etching treatment gas. After the etching, the photoresist was removed by an oxygen plasma ashing process.
[0069]
(3) Hole pattern on copper (Cu) wiring
700 μm thick Si / Cu / Si_ThreeN_Four/ SiO₂A laminated substrate of [substrate / 400/50/300 (nm)] was patterned using a novolac resin positive photoresist and subjected to plasma etching. Chlorine-based and fluorine-based gases were sequentially used as the etching treatment gas. After the etching, the photoresist was removed by an oxygen plasma ashing process.
[0070]
The substrate was cleaned using the cleaning composition obtained in Examples 1 to 15 and Comparative Examples 1 to 5 described in Tables 1 and 2. In Examples 1 to 9, 11 and Comparative Examples 1 to 5, the substrate was cleaned by immersing it in a cleaning composition at 30 ° C. for 10 minutes. In Example 10, cleaning was performed by spraying the cleaning composition on the substrate to be treated in the air at 30 ° C. for 5 minutes. In Examples 12 and 13, the substrate was cleaned by immersing it in the cleaning composition at 60 ° C. and 50 ° C. for 10 minutes, respectively. In Examples 14 and 15, the substrate was cleaned by immersing it in the cleaning composition at 30 ° C. for 10 minutes. After cleaning, the substrate was rinsed with water. After drying, the surface of the substrate was magnified 50,000 times with a field emission scanning electron microscope, and 100 formed wirings or hole patterns were observed, and their depot cleaning properties and wiring corrosivity were evaluated according to the following criteria. The results are shown in Tables 1 and 2.
[0071]
[Depot cleanability]
Depot cleaning rate = (number of patterns from which depots have been completely removed / 100) × 100
Evaluation criteria
A: 95% to 100%, B: 90% to less than 95%, C: 80% to less than 90%, D: 0% to less than 80%
[0072]
[Corrosion of wiring]
Corrosion rate = (number of resist patterns in which stains or pitting corrosion is recognized) / 100) × 100
Evaluation criteria
A: 0% or more and less than 2.5%, B: 2.5% or more and less than 5%, C: 5% or more and less than 10%, D: 10% or more and 100% or less
In addition, in said evaluation, let all evaluations be A or B as a pass product.
[0073]
[Table 1]

[0074]
[Table 2]

[0075]
From the results shown in Tables 1 and 2, the cleaning compositions obtained in Examples 1 to 15 were more suitable for cleaning depots present in various wirings than the cleaning compositions obtained in Comparative Examples 1 to 5. It can be seen that it is excellent in corrosion resistance and hardly corrodes.
[0076]
Example 16
An element isolation oxide film, a polycrystalline Si film, a WN film, and a W film are sequentially deposited on an n-type silicon substrate to form a WN / W composite film. Etching and ashing are performed on the WN / W composite film by a normal photoetching process using a resist pattern as a mask, and then the substrate is showered in air using the cleaning composition of any of Examples 1-15. Etching residue and ashing residue (hereinafter referred to as deposit) are washed. Thereafter, the wiring is observed using the method described above.
[0077]
Next, after p-type and n-type LDD regions, p-type and n-type source and drain regions are provided by ion implantation, an interlayer insulating film, SiO 2 is formed on the entire surface.₂Are stacked and the surface is planarized using a chemical mechanical polishing (CMP) method.
Next, contact holes reaching the p-type source, domain region, n-type source and drain region are formed, and W is buried to form a W plug.
[0078]
Next, a TiN film and an Al film are sequentially deposited on the entire surface, and normal photoetching is performed using the resist pattern as a mask. Then, the said board | substrate is air-showered (30 degreeC, 5 minutes) using the cleaning composition in any one of Examples 1-15, and an etching residue and an ashing residue (henceforth a deposit) are wash | cleaned. Thereafter, the wiring is observed using the method described above.
At the above two time points, it is observed that the Al wiring and the W electrode on the substrate are both extremely low in deposits and no corrosion occurs.
[0079]
【The invention's effect】
By using the cleaning method of the present invention, it is possible to easily and quickly clean even a depot that has been altered by high energy treatment, and it is possible to suppress corrosion on wiring materials such as aluminum, tungsten, and alloys thereof. As a result, it can greatly contribute to improving the productivity of semiconductor elements, LCDs and the like.
In addition, by using the cleaning method of the present invention in a plurality of deposition cleaning processes during the semiconductor manufacturing process, an excellent effect that the installation space of the cleaning apparatus and the storage space for the cleaning liquid can be significantly reduced is achieved. Is done.

Claims (4)

(A) an acid and / or salt thereof having an n-stage basic acid dissociation index pKa _n (25 ° C.) of 3 or more and 11 or less, (b) water, (c) in the molecule A cleaning agent composition containing a chelating agent containing a nitrogen atom and having a pH of 6 or more and 11 or less, and at least (A) a tungsten or tungsten alloy wiring or electrode and (B) aluminum or an aluminum alloy A semiconductor substrate cleaning method for cleaning a semiconductor substrate including wiring at 15 to 60 ° C. to remove residues on the semiconductor substrate after etching and ashing . The cleaning method according to claim 1, wherein the cleaning is performed under a temperature condition of 25 to 40 ° C. The cleaning method according to claim 1 or 2, wherein the content of the component (a) in the cleaning composition is 0.01 to 65% by weight. The cleaning method according to claim 1, wherein the semiconductor substrate is cleaned by at least one selected from the group consisting of immersion, in-liquid shower, and in-air shower.