JP3590273B2 - Semiconductor device manufacturing method and processing liquid generating apparatus - Google Patents

Description

また電界の向きと液中のイオン種に応じて、陽イオン交換膜６１１と陰イオン交換膜では以下のようなイオンの移動が生じる。
【００８３】
陽イオン交換膜：Ｈ^＋ 、電極６４２側から電極６４１側へ
陰イオン交換膜：Ｃｌ⁻ 、電極６４３側から電極６４２側へ
従って、電極６４２と電極６４３間で生じる電気分解反応とイオン移動によって、電極６４２が設置された領域のＨ^＋ 、Ｏ_２ 、Ｏ_３ 、ＨＣｌＯ_ｘ 等の濃度が増加する。これは低ｐＨ、高酸化電位の液の生成を意味する。他方、電極６４２と電極６４１間で生じる電気分解反応とイオン移動によって、電極６４２が設置された領域のＯ_２ Ｏ_３ 、濃度は増加するが、Ｈ^＋ 濃度はほとんど変化しない（電極６４２表面ではＨ^＋ の生成反応が起きるが、電極８４１が設置された領域へとＨ^＋ が移動することによる）。これは高酸化電位の液の生成を意味する。
【００８４】
以上から、排出口６３２から排出される液は、導入口６２２から導入した液よりも低ｐＨ、高酸化電位となることがわかる。排出口６３２の排出液のｐＨと酸化還元電位を測定したところ、ｐＨ＝６、酸化還元電位＝０．８５Ｖであった。
【００８５】
また、図６に示す従来の装置は、容器７０１内が陰イオン交換膜７１２によって２つの領域に分けられており、液の導入口７２１，７２２と排出口７３１，７３２によって、領域ごとに液の導入と排出を行うことができる。さらにそれぞれの領域には電極が備えられており（電極７４１，７４２）、これらの電極間で電流を流すことによって、各領域に導入された液を電気分解することが可能である。
【００８６】
ここでは、この装置の導入口７２１にはＨＣｌを微量（２×１０^−５ｍｏｌ／ｌ）溶解させた水溶液を、導入口７２２には塩化アンモニウム水溶液を溶解（２×１０^−３ｍｏｌ／ｌ）した水溶液を導入し、電極７４１，７４２のそれぞれに５０Ｖと３０Ｖの電位を与えて水溶液を電気分解し、排出口７３１から排出される液を洗浄に用いる。
【００８７】
ここで各電極表面では、各々の電位差に応じて主に次のような反応が生じる。

また電極７４１は電極７４２よりも高電位であるため、陰イオン交換膜ではＣｌ⁻ が電極７４２側から電極７４１側へ移動する。
【００８８】
このような反応が生じるため、排出口７３１から排出される液は、導入口７２１から導入した液よりもＨ^＋ 、Ｃｌ⁻ 、Ｏ_２ Ｏ_３ 濃度が増加する。実際排出口７３１の排出液のｐＨと酸化還元電位を測定したところ、ｐＨ＝６、酸化還元電位＝０．６５Ｖであった。
【００８９】
次に図５、図６で生成した洗浄液の洗浄効果について調べるため、表面の自然酸化膜を弗酸で除去した後に、故意にＣｕで汚染（約１×１０^１１ａｔｏｍｓ／ｃｍ^２ ）したシリコンウエハ３枚ずつをそれらの液で洗浄した。洗浄後、ＨＦ／Ｈ_２ Ｏ_２ 液によって表面の残留Ｃｕを回収し、回収液をＩＣＰ−質量分析法によって分析したところ、図５の洗浄液で洗浄したウエハのＣｕ濃度は３枚とも検出感度（約１×１０^９ ａｔｏｍｓ／ｃｍ^２ ）以下であったのに対し、図６の装置で生成した液で洗浄したウエハからは、約２×１０^１０ａｔｏｍｓ／ｃｍ^２ （３枚の平均値）のＣｕが検出された。
【００９０】
このようにＣｕの洗浄効率が異なる理由を図面を参照して説明することができる。図７に、ＣｕのｐＨ−酸化還元電位平衡図を示す。図中、Ｃｕ^２＋とＣｕ間の境界線は、上記汚染のように、Ｃｕより還元性が高いＳｉ上に付着したＣｕに対しては一点鎖線で、還元性が低い、例えばＣｕ表面でのＣｕ付着の場合は実線で表される。またこの図には、図５と図６で生成した洗浄液のｐＨ−酸化還元電位に対応する位置を白丸と黒丸で示している。この図から、酸化電位が高い、図５で生成した洗浄液はＣｕ^２＋の溶解域にあり、ウエハ表面のＣｕ汚染を効率良く除去するのに対し、酸化電位が比較的低い、図６で生成した洗浄液は、Ｃｕの平衡域にあるため、ウエハ表面のＣｕをあまり除去できないことがわかる。
【００９１】
このように本発明を用いることにより、従来よりも酸化電位が高い洗浄液を生成することができ、ウエハ表面の汚染Ｃｕを効率よく除去することができた。なおこのような高酸化電位の液は、試料表面の有機物汚染やレジストなどの有機薄膜等の除去、自然酸化膜形成によるシリコン等の表面安定化処理などにも用いることができる。また上記実施形態では導入口６２３にＣｌ⁻ を含む液を使用したが、Ｆ⁻ などのハロゲンイオン、ＨＦ_２ ⁻ のようなハロゲン化水素イオン、ＣｌＯ_ｘ ⁻ 、ＢｒＯ_ｘ ⁻ 、ＩＯ_ｘ ⁻ などの酸化ハロゲンイオン、ＳＯ_ｘ ^２−、ＮＯ_ｘ ⁻ 、ＰＯ_ｘ ^３−、ＨＯ_２ ⁻ などを含有する液を使用しても同様の液を生成することができる。
【００９２】
図８は、本発明に係る第６の例に用いる洗浄液生成装置の概略図である。なお、比較のため図６に示す装置も使用した。この装置で生成した洗浄液でシリコンウエハの洗浄を行い、洗浄効果を比較した。図８の装置は図５に示した装置と基本構成は同じであり、電極に印加する電位や導入する溶液などが一部異なるだけである。まず以下では図８の装置の構成と、その装置を用いた洗浄液の生成方法について説明する。
【００９３】
図８に示す装置は、容器９０１内が陽イオン交換膜９１１と陰イオン交換膜９１２によって３つの領域に分けられており、液の導入口９２１，９２２，９２３と排出口９３１，９３２，９３３によって、領域ごとに液の導入と排出を行うことができる。さらにそれぞれの領域には電極が備えられており（電極９４１，９４２，９４３）、これらの電極間で電流を流すことによって、各領域に導入された液を電気分解することが可能である。
【００９４】
この例では、この装置の導入口９２１と導入口９２２には支持電解質としてＨＣｌを微量（２×１０^−５ｍｏｌ／ｌ）溶解させた水溶液を、導入口９２３には塩化アンモニウム水溶液を溶解（２×１０^−３ｍｏｌ／ｌ）した水溶液を導入し、電極９４１，９４２，９４３のそれぞれに１００Ｖ、５０Ｖ、４０Ｖの電位を与えて水溶液を電気分解し、排出口９３２から排出される液を洗浄に用いた。
【００９５】
ここで、各電極表面では、各々の電位差に応じて主に次のような反応が生じる。

また電界の向きと液中のイオン種に応じて、陽イオン交換膜９１１と陰イオン交換膜９１２では以下のようなイオンの移動が生じる。
【００９６】
陽イオン交換膜：Ｈ^＋ 、電極９４１側から電極９４２側へ
陰イオン交換膜：Ｃｌ⁻ 、電極９４３側から電極９４２側へ
従って、電極９４２と電極９４３間で生じる電気分解反応とイオン移動によって、電極９４２が設置された領域のＨ^＋ 、Ｏ_２ Ｏ_３ 、ＨＣｌＯ_ｘ 等の濃度が増加する。これは低ｐＨ、高酸化電位の液の生成を意味する。他方電極９４２と電極９４１間で生じる電気分解反応とイオン移動によって、電極９４２が設置された領域のＨ_２ 濃度が増加するが、Ｈ^＋ 濃度はほとんど変化しない。これは、電極９４２表面ではＨ^＋ の消失反応が起きるが、電極９４１が設置された領域からＨ^＋ が移動し、減少したＨ^＋ を補うことによる。このように、Ｈ_２ 濃度が増加し、Ｈ^＋ 濃度が変化しないことから、低酸化電位の液が生成する。
【００９７】
以上から、排出口９３２から排出される液は、導入口９２２から導入した液よりもｐＨに関しては低くなること、酸化還元電位の変化については、電極９４２−電極９４１間に流れる電流と、電極９４２−電極９４３間に流れる電流との大小関係で決まることがわかる。
【００９８】
この例では、電位差の違いを反映して、前者の電極間では後者の電極間に比べてより多くの電流が流れたため、酸化電位は減少した。排出口９３２の排出液のｐＨと酸化還元電位を測定したところ、ｐＨ＝０、酸化還元電位もほぼ０Ｖであった。
【００９９】
また、図６の従来の装置の導入口７２１にはＨＣｌを微量（２×１０^−５ｍｏｌ／ｌ）溶解させた水溶液を、導入口７２２には塩化アンモニウム水溶液を溶解（２×１０^−３ｍｏｌ／ｌ）した水溶液を導入し、電極７４１，７４２のそれぞれに９０Ｖと０Ｖの電位を与えて水溶液を電気分解し、排出口７３１から排出される液を洗浄に用いた。
【０１００】
ここで各電極表面では、各々の電位差に応じて主に次のような反応が生じる。

また電極７４１は電極７４２よりも高電位であるため、陰イオン交換膜ではＣｌ⁻ が電極７４２側から電極７４１側へ移動する。
【０１０１】
このような反応が生じるため、排出口７３１から排出される液は、導入口７２１から導入した液よりもＨ^＋ 、Ｃｌ⁻ 、Ｏ_２ 、Ｏ_３ が増加する。実際排出口７３２の排出液のｐＨと酸化還元電位を測定したところ、ｐＨ＝０、酸化還元電位＝１．５Ｖであった。
【０１０２】
次に図６に示す装置、及び図８に示す装置で生成した洗浄液の洗浄効果について調べるため、表面がＴｉで汚染（約５×１０^１０ａｔｏｍｓ／ｃｍ^２ ）したシリコンウエハ３枚ずつをそれらの液で洗浄した。
【０１０３】
洗浄後、ＨＦ液によって表面の残留Ｔｉを回収し、回収液をＩＣＰ−質量分析法によって分析した。その結果、図８の洗浄液で洗浄したウエハのＴｉ濃度は３枚の平均値で約３×１０^９ ａｔｏｍｓ／ｃｍ^２ であったのに対し、図６の装置で生成した液で洗浄したウエハからは、３枚の平均で約４×１０^１０ａｔｏｍｓ／ｃｍ^２ のＴｉが検出された。
【０１０４】
このようにＴｉの洗浄効率が異なる理由を図９を参照して説明する。図９は、ＴｉのｐＨ−酸化還元電位平衡図である。図９には、図８と図６で生成した洗浄液のｐＨ，酸化還元電位に対応する位置を白丸と黒丸で示している。この図から、酸化電位が高い、図６で生成した洗浄液はＴｉＯ_２ の領域にあり、ウエハ表面のＴｉはほとんど除去されないこと、これに対して酸化電位が比較的低い、図８で生成した洗浄液は、ＴｉＯ_２ の領域にはあるがＴｉ^２＋との境界領域に近いため、ウエハ表面のＴｉの一部をＴｉ^２＋として溶解したと考えられる。
【０１０５】
このように，本発明を用いることにより、低ｐＨで低酸化電位の洗浄液を生成し、従来方法で生成した洗浄液よりもウエハ表面の汚染Ｔｉを効率良く除去することができた。また上記実施形態では導入口９２３にＣｌ⁻ を含む液を使用したが、Ｆ⁻ などのハロゲンイオン、ＨＦ_２ ⁻ のようなハロゲン化水素イオン、ＣｌＯ_ｘ ⁻ 、ＢｒＯ_ｘ ⁻ 、ＩＯ_ｘ ⁻ などの酸化ハロゲンイオン、ＳＯ_ｘ ^２−、ＮＯ_ｘ ⁻ 、ＰＯ_ｘ ^３−、ＨＯ_２ ⁻ などを含有する液を使用しても同様の液を生成することができる。
【０１０６】
図１０に、本発明にかかる処理液生成装置の第７の例を表す概略図を示す。ここでは、図１０と図１１に示す装置で生成した洗浄液でシリコンウエハの洗浄を行い、洗浄効果を比較する。なお、図１０の装置は図５に示した装置と、図１１の装置は図６に示した装置と基本構成は同じであり、電極に印加する電位や導入する溶液などが一部異なるだけである。以下では図１０、図１１に示す装置と構成と、その装置を用いた洗浄液の生成方法について説明する。
【０１０７】
図１０に示す装置は、容器１１０１内が陽イオン交換膜１１１１と陰イオン交換膜１１１２によって３つの領域に分けられており、液の導入口１１２１，１１２２，１１２３と排出口１１３１，１１３２，１１３３によって、領域ごとに液の導入と排出を行うことができる。さらにそれぞれの領域には電極１１４１，１１４２，１１４３が備えられており、これらの電極間で電流を流すことによって、各領域に導入された液を電気分解することが可能である。
【０１０８】
この例では、この装置の導入口１１２２と導入口１１２３には支持電解質としてＮＨ_４ ＯＨを微量（２×１０^−５ｍｏｌ／ｌ）溶解させた水溶液を、導入口１１２１には酢酸アンモニウム水溶液を溶解（２×１０^−３ｍｏｌ／ｌ）した水溶液を導入し、電極１１４１，１１４２，１１４３のそれぞれに２０Ｖ、１０Ｖ、５０Ｖの電位を与えて水溶液を電気分解し、排出口１１３２から排出される液を洗浄に用いた。
【０１０９】
ここで各電極表面では、各々の電位差に応じて主に次のような反応が生じる。
電極１１４３：２Ｈ_２ Ｏ→４Ｈ^＋ ＋Ｏ_２ ＋４ｅ⁻
電極１１４２：２Ｈ_２ Ｏ＋２ｅ⁻ →Ｈ_２ ＋２ＯＨ⁻
電極１１４１：２Ｈ_２ Ｏ→４Ｈ^＋ ＋Ｏ_２ ＋４ｅ⁻
また電界の向きと液中のイオン種に応じて、陽イオン交換膜１１１１と陰イオン交換膜１１１２では以下のようなイオンの移動が生じる。
【０１１０】
陽イオン交換膜：ＮＨ_４ ^＋ 、電極１１４１側から電極１１４２側へ
陰イオン交換膜：ＯＨ⁻ 、電極１１４２側から電極１１４３側へ
従って、電極１１４２と電極１１４３間で生じる電気分解反応とイオン移動によって、電極１１４２が設置された領域のＨ_２ 等の濃度が増加するが、ＯＨ⁻ 濃度はほとんど変化しない。電極１１４２表面ではＯＨ⁻ が生成するが、ＯＨ⁻ は、陰イオン交換膜１１１２を介して、電極１１４３が設置される領域に移動するためである。これは、低酸化電位の液の生成を意味する。
【０１１１】
また電極１１４２と電極１１４１間で生じる電気分解反応とイオン移動によって、電極１１４２が設置された領域のＨ_２ 、ＯＨ⁻ 濃度が増加する。これは高ｐＨ、低酸化電位の液の生成を意味する。
【０１１２】
以上から、排出口１１３２から排出される液は、導入口１１２２から導入した液よりもｐＨ、酸化還元電位のいずれも低くなることがわかる。排出口１１３２の排出液のｐＨと酸化還元電位を測定したところ、ｐＨ＝８、酸化還元電位は−０．４５Ｖであった。
【０１１３】
また、図１０に示す装置は、容器１２０１内が陽イオン交換膜１２１１によって２つの領域に分けられており、液の導入口１２２１，１２２２と排出口１２３１，１２３２によって、領域ごとに液の導入と排出を行うことができる。さらにそれぞれの領域には電極が備えられており（電極１２４１，１２４２）、これらの電極間で電流を流すことによって、各領域に導入された液を電気分解することが可能である。
【０１１４】
図１１に記す装置では、その導入口１２２１には支持電解質としてＮＨ_４ ＯＨを微量（２×１０^−５ｍｏｌ／ｌ）溶解させた水溶液を、導入口１２２２には酢酸アンモニウム水溶液を溶解（２×１０^−３ｍｏｌ／ｌ）した水溶液を導入し、電極１２４１，１２４２のそれぞれに１０Ｖと２０Ｖの電位を与えて水溶液を電気分解し、排出口１２３１から排出される液を洗浄に用いた。
【０１１５】
ここで各電極表面では、各々の電位差に応じて主に次のような反応が生じる。
電極１２４１：２Ｈ_２ Ｏ＋２ｅ⁻ →Ｈ_２ ＋２ＯＨ⁻
電極１２４２：２Ｈ_２ Ｏ→４Ｈ^＋ ＋Ｏ_２ ＋４ｅ⁻
また電極１２４２は電極１２４１よりも高電位であるため、陽イオン交換膜１２１１ではＮＨ^４＋が電極１２４２側から電極１２４１側へ移動する。
【０１１６】
このような反応が生じるため、排出口１２３１から排出される液は、導入口１２２１から導入した液よりもＯＨ⁻ 、Ｈ_２ 濃度が増加する。排出口１２３２の排出液のｐＨと酸化還元電位を測定したところ、ｐＨ＝８、酸化還元電位＝−０．３０Ｖであった。
【０１１７】
次に図１０と図１１に示す装置で生成した洗浄液による洗浄結果について説明する。
まずＡｌの埋め込み配線を形成するため、絶縁膜上の溝形成→Ａｌスパッタ→Ａｌ ＣＭＰを行った。このＣＭＰによって絶縁膜やＡｌ表面に研磨粒子が残留したため、図１０あるいは図１１に示す装置で生成した洗浄液中にウエハを浸漬し、約１ＭＨｚの超音波を１０分間照射した。ウエハ表面に付着していた約１−３万個の研磨粒子は、図１０に示す装置と図１１に示す装置のいずれの装置で生成した洗浄液を用いても、この超音波処理によって約５０個以下に低減できた。しかし、図１０に示す装置で生成した液を使用した場合にはＡｌは全く腐食されなかったのに対し、図１１に示す装置で生成した洗浄液を用いたウエハでは約５％のＡｌに腐食が見られた。これは前者は後者に比べて酸化電位が低いため、Ａｌの酸化、溶出反応（Ａｌ＋４ＯＨ⁻ →Ａｌ（ＯＨ）_４ ⁻ ＋３ｅ⁻ ）が抑制されたためと考えられる。
【０１１８】
このように本発明を用いることで低酸化電位の洗浄液を生成し、Ａｌを腐食させることなくＣＭＰ研磨粒子を除去できた。なお本発明で生成した、弱アルカリ性で還元性が高い液は、ドライエッチング等の後に試料表面に残留するハロゲン等のイオン性残留物の除去や、半導体や金属等の自然酸化膜の還元除去、水素終端化処理などにも用いても良好な洗浄効果をあげることができる。また上記実施形態では導入口１１２１にＮＨ_４ ^＋ を含む液を使用したが、例えばＮ（ＣＨ_３ ）_４ ^＋ 及びＮ（ＣＨ_３ ）_３ Ｃ_２ Ｈ_４ ＯＨ^＋ 等のアルキルアンモニウムイオンを含有する液を使用しても同様の液を生成することができる。
【０１１９】
図１２は、本発明に係る第８の例に使用される洗浄液生成装置の概略図である。また図１１には、比較として従来装置の該略図を示す。本発明に係る第７の例では、図１１と図１２に示す装置で生成した洗浄液でシリコンウエハの洗浄を行い、洗浄効果を比較するものである。図１２の装置は図５に示した装置と基本構成は同じであり、電極に印加する電位や導入する溶液などが一部異なるだけである。以下では図１２の装置の構成と、その装置を用いた洗浄液の生成方法について説明する。
【０１２０】
図１２に示す装置は、容器１３０１内が陽イオン交換膜１３１１と陰イオン交換膜１３１２によって３つの領域に分けられており、液の導入口１３２１，１３２２，１３２３と排出口１３３１，１３３２，１３３３によって、領域ごとに液の導入と排出を行うことができる。さらにそれぞれの領域には電極１３４１，１３４２，１３４３が備えられており、これらの電極間で電流を流すことによって、各領域に導入された液を電気分解することが可能である。
【０１２１】
本実施形態では、この装置の導入口１３２２と導入口１３２３にはＮＨ_４ ＯＨ水溶液（２×１０^−５ｍｏｌ／ｌ）を、導入口１３２１には塩化アンモニウム水溶液を（２×１０^−３ｍｏｌ／ｌ）導入し、電極１３４１，１３４２，１３４３のそれぞれに９０Ｖ、７０Ｖ、０Ｖの電位を与えて水溶液を電気分解し、排出口１３３２から排出される液を洗浄に用いた。
【０１２２】
ここで各電極表面では、各々の電位差に応じて主に次のような反応が生じる。
電極１３４３ ：２Ｈ_２ Ｏ＋２ｅ⁻ →Ｈ_２ ＋２ＯＨ⁻
電極１３４２の電極１３４３側：２ＯＨ⁻ →２Ｈ_２ Ｏ＋Ｏ_２ ＋４ｅ⁻
電極１３４２の電極１３４１側：２Ｈ_２ Ｏ＋２ｅ⁻ →Ｈ_２ ＋２ＯＨ⁻
電極１３４１ ：２Ｈ_２ Ｏ→４Ｈ^＋ ＋Ｏ_２ ＋４ｅ⁻
また電界の向きと液中のイオン種に応じて、陽イオン交換膜１３１１と陰イオン交換膜１３１２では以下のようなイオンの移動が生じる。
【０１２３】
陽イオン交換膜：ＮＨ_４ ^＋ 、電極１３４１側から電極１３４２側へ
陰イオン交換膜：ＯＨ⁻ 、電極１３４３側から電極１３４２側へ
従って、電極１３４２と電極１３４３間で生じる電気分解反応とイオン移動によって、電極１３４２が設置された領域のＯ_２ 等の濃度が増加するが、ＯＨ⁻ 濃度はほとんど変化しない（電極１３４２表面ではＯＨ⁻ が消失するが、陰イオン交換膜１３１２を介して、電極１３４３が設置される領域からＯＨ⁻ が移動して減少分を補償する）。これは高酸化電位の液の生成を意味する。他方電極１３４２と電極１３４１間で生じる電気分解反応とイオン移動によって、電極１３４２が設置された領域のＨ_２ 、ＯＨ⁻ 濃度が増加する。これは高ｐＨ、低酸化電位の液の生成を意味する。
【０１２４】
以上から、排出口１１３２から排出される液は、導入口１３２２から導入した液よりもｐＨは増加すること、酸化還元電位の変化については、電極１３４２−電極１３４１間に流れる電流と、電極１３４２−電極１３４３間に流れる電流との大小関係で決まることがわかる。この例では、電位差の大小関係に応じて、後者の方がより多くの電流が流れ、排出口１３３２から排出される液は導入口１３２２から導入された液よりも酸化電位は上昇した。排出口１３３２の排出液のｐＨと酸化還元電位を測定したところ、ｐＨ＝９、酸化還元電位は約０．７Ｖであった。
【０１２５】
また、この例では、図１１の装置の導入口１２２１にはＮＨ_４ ＯＨ水溶液（２×１０^−５ｍｏｌ／ｌ）を、導入口１２２２には酢酸アンモニウム水溶液を溶解（２×１０^−３ｍｏｌ／ｌ）した水溶液を導入し、電極１２４１，１２４２のそれぞれに７０Ｖと９０Ｖの電位を与えて水溶液を電気分解し、排出口１２３１から排出される液を洗浄に用いた。
【０１２６】
ここで各電極表面では、各々の電位差に応じて主に次のような反応が生じる。
電極１２４１：２Ｈ_２ Ｏ＋２ｅ⁻ →Ｈ_２ ＋２ＯＨ⁻
電極１２４２：２Ｈ_２ Ｏ→４Ｈ^＋ ＋Ｏ_２ ＋４ｅ⁻
また電極１２４２は電極１２４１よりも高電位であるため、陽イオン交換膜１２１１ではＮＨ_４ ^＋ が電極１２４２側から電極１２４１側へ移動する。
【０１２７】
このような反応が生じるため、排出口１２３１から排出される液は、導入口１２２１から導入した液よりもＯＨ⁻ 、Ｈ_２ 濃度が増加する。排出口１２３２の排出液のｐＨと酸化還元電位を測定したところ、ｐＨ＝９、酸化還元電位＝−０．６５Ｖであった。
【０１２８】
次に、このような洗浄液を用いてウエハを洗浄した結果について述べる。
まず反応性イオンエッチングによってシリコン上の絶縁膜にコンタクトホールを開孔し、その後ホール底面のシリコン表面のエッチング残査や損傷層を除去するため、図１１に示す装置と図１２の装置で生成した洗浄液に試料を浸漬し、１０分間処理した。その結果、図１２に示した装置で生成した液によって洗浄した場合は、シリコン表面の残査が除去されると共にシリコンが約１ｎｍエッチングされ、エッチングダメージ層が除去された。この時シリコン表面の平坦度はほとんど変化しなかった。これに対し、図１１の装置で生じた液で処理をした場合は、シリコン表面が約１０ｎｍもエッチングされた。またエッチングされたシリコンには数ｎｍの表面荒れが生じていた。
【０１２９】
これは、図１１の装置による液はアルカリ性であるため、コンタクトホール底面のシリコンがＯＨ⁻ イオンによってエッチングされたためである。表面荒れは、このエッチングがシリコンの面方位依存性を持つ（例えば（１１１）面のエッチング速度＜（１００）面のエッチング速度）ことに起因している。他方図１３に示した装置で生成した洗浄液で処理した場合は、液の酸化性が高いためホール底面のシリコン表面はまず自然酸化膜で被覆され、この酸化膜がＯＨ⁻ によってエッチングされる。従ってシリコンのエッチング量は少なく、また表面荒れもあまり生じない。
【０１３０】
このように本発明を用いることでコンタクトホールの洗浄に適した液を生成することができた。なお、このような弱アルカリで酸化性が高い液は、シリコン酸化膜表面などのパーティクル除去や汚染金属除去などにも有効である。さらにＨＣｌやＮＨ_４ Ｃｌなどを、導入口１３２２や１３２３から導入する液もしくは排出口１３３２から排出される液に混入させ、液中にＣｌ⁻ を導入させた液で処理すると、Ｆｅ等の金属汚染除去効率が向上した。これは液中のＣｌ⁻ が、溶解した金属イオンと錯イオンを作って安定化させる効果を持つためである。Ｃｌ⁻ 以外にもＢｒ⁻ 、Ｉ⁻ 、ＳＯ_ｘ ^２−、ＮＯ_ｘ ⁻ 、キレート剤などを洗浄液に含有させることによっても同様の効果が見られた。また上記実施形態では導入口１３２１にＮＨ_４ ^＋ を含む液を使用したが、例えばＮ（ＣＨ_３ ）_４ ^＋ 及びＮ（ＣＨ_３ ）_３ Ｃ_２ Ｈ_４ ＯＨ^＋ 等のアルキルアンモニウムイオンを含有する液を使用しても同様の液を生成することができる。
【０１３１】
なお本発明は上述した例に限定されるものではなく、例えば本発明で生成した溶液を、弗酸などの別の洗浄液と混合して使用したり、洗浄以外の用途、例えばポリシリコン等の薄膜除去やＣＭＰの研磨液等として使用することもできる。また上述した実施形態では陽イオン交換膜と陰イオン交換膜とで挟まれた領域に一つの電極を設置し、その電極と他の二つの領域の電極との間で電気分解を行ったが、陽イオン交換膜と陰イオン交換膜とで挟まれた領域に二つの電極を設置し、その各々と他の二つの電極との間で電気分解を行ってもよい。その他、本発明はその趣旨を逸脱しない範囲内において種々変形して実施可能である。
【０１３２】
【発明の効果】
本発明の処理液の生成装置によれば、アノード水やカソード水のｐＨと酸化還元電位とを独立に制御することができる。このため、例えば酸化電位が高いカソード水や還元電位が高いアノード水を得ることが可能となる。
【０１３３】
また、本発明の半導体装置の製造方法によれば、汚染金属の種類に応じたｐＨと酸化還元電位を有する溶液を自在に得ることができるため、汚染金属を効果的に除去したり試料を金属で汚染することなく洗浄することが可能とし、さらに、陽極の腐食抑制や、陰極への金属イオン吸着抑制を可能とする。
【図面の簡単な説明】
【図１】処理水のｐＨと酸化還元電位の範囲を表す図
【図２】本発明にかかる処理液生成装置の第１の例を表す該略図
【図３】本発明にかかる処理液生成装置の第２の例を表す該略図
【図４】本発明にかかる処理液生成装置の第３の例を表す該略図
【図５】本発明にかかる処理液生成装置の第５の例を表す概略図
【図６】従来の洗浄液生成装置の概略図
【図７】ＣｕのｐＨ−酸化還元電位平衡図
【図８】本発明にかかる処理液生成装置の第６の例を表す概略図
【図９】ＴｉのｐＨ−酸化還元電位平衡図
【図１０】本発明にかかる処理液生成装置の第７の例を表す概略図
【図１１】従来の洗浄液生成装置の概略図
【図１２】本発明にかかる処理液生成装置の第８の例を表す概略図
【図１３】ｐＨと酸化還元電位Ｅに対するＦｅの状態図
【図１４】ｐＨと酸化還元電位Ｅに対するＣｒの状態図
【符号の説明】
１１、２１、３１…容器
１２、２２、３２…陽極
１３、２３、３３…陰極
１４、２４、３４ａ、３４ｂ…隔膜
６１１，９１１，１１１１，１２１１，１３１１…陽イオン交換膜
６１２，７１２，９１２，１１１２，１３１２…陰イオン交換膜
６４１，６４２，６４３，９４１，９４２，９４３，１１４１，１１４２，１１４３，１２４１，１２４２，１３４１，１３４２，１３４３…電極[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor device, and an apparatus for generating a processing liquid used in a cleaning step or chemical mechanical polishing (so-called CMP) in the manufacture of a semiconductor device.
[0002]
[Prior art]
Conventionally, chemicals such as hydrochloric acid and ammonia water have been used for wet processing such as cleaning of a sample such as a semiconductor wafer and film peeling, but recently, cleaning with electrolytic ionic water has been spreading.
[0003]
Electrolytic ionized water is used to conduct electricity between a pair of electrodes installed through a diaphragm in an aqueous solution, and to use “OH” on the anode side.⁻  → OH + e⁻  ”And“ H ”on the cathode side⁺  + E⁻  It is a solution obtained by causing a reaction such as "H". The solution on the anode side with respect to the diaphragm, i.e., the anode water is OH⁻  Low concentration and acidic. The solution on the cathode side, ie, the cathode water, is H⁺  Low concentration and alkaline. OH is “2OH → O + H”₂  O ”,“ 2O → O₂  ”And“ O + O ”₂  → O₃  ), The anode water is O, O₂  , O₃  Etc., and its redox potential is higher than that of a normal acid solution having an equivalent pH. Similarly, the cathode water is H, H₂  , The oxidation-reduction potential is lower than that of a normal alkaline solution having the same pH.
[0004]
Anode water is used for removing contaminant metals on the surface of a sample by utilizing its properties of strong acidity and high oxidation potential, and is particularly attracting attention as a cleaning solution for noble metals such as copper. Since noble metals are hard to ionize, they do not dissolve in ordinary acids such as hydrochloric acid and hydrofluoric acid. However, since anode water has a high oxidation potential, it can deprive the noble metal of electrons, ionize the noble metal and elute it into the solution.
[0005]
However, conversely, some metals dissolve in ordinary acids but are stably present as oxides or hydroxides in solutions having a high oxidation potential. For example, iron has a low oxidation potential when the pH is between about 2 and about 8²⁺But eluted as₂  O₃  As a residue. FIG. 13 shows a phase diagram of Fe with respect to pH and oxidation-reduction potential E. As shown in the figure, Fe can be dissolved by using anode water having a pH of about 2 or less. This is because in a low pH solution, even at a high oxidation potential, Fe²⁺Is stably present. However, low-pH or high-concentration anolyte water requires more chemicals and power during the generation and detoxification treatment after use than dilute anolyte water. The amount of waste generated after detoxifying high-concentration anode water is also greater than in the case of lean anode water. In order to effectively utilize finite earth resources, consumption of such large amounts of resources and power and generation of wastes must be avoided.
[0006]
On the other hand, acids are generally used to remove contaminant metals, while alkaline solutions are used to clean particles. For example, when a silicon oxide film to which particles are attached is immersed in an alkaline aqueous solution, the silicon oxide film is etched by the solution. For this reason, the distance between the particle and the surface of the silicon oxide film increases, and the Van der Waals force acting between the surfaces of the particles is weakened, so that the particle is easily removed. Further, in an aqueous solution having a large pH, the surface of a sample or a particle tends to be negatively charged. Therefore, in an alkaline solution, an electrostatic repulsion acts, so that the particles once removed hardly adhere to the sample surface. Cathode water is also used for removing particles because it is alkaline.
[0007]
However, in an alkaline aqueous solution, the metal is easily stabilized as a hydroxide, and therefore, washing with an alkaline solution may not remove metal contamination or may deposit metal ions contained in the solution. . FIG. 14 shows a phase diagram of Cr with respect to pH and redox potential E. As shown, for example, when the oxidation potential is low at a pH between about 4 and 14, Cr may be present as an oxide or hydroxide. Therefore, if the sample is washed with a normal alkaline solution or highly reducing cathode water, the sample may be contaminated with chromium.
[0008]
Further, silicon is etched when immersed in an alkaline aqueous solution. This etching has a plane orientation dependence, and the etching rate of the (100) plane is higher than that of the (111) plane. For this reason, when the wafer is washed with cathode water having a large pH value to remove particles after CMP of Poly-Si or after opening of a contact hole, a large amount of silicon exposed on the wafer surface is etched, There arises a problem that the silicon surface becomes rough. Further, in a solution having low oxidizing property, organic contamination on the sample surface is hardly removed. Therefore, when silicon contaminated with organic substances is treated with conventional cathode water, the silicon surface is partially etched using the contaminated organic substances as a mask, and the degree of surface roughness is further increased.
[0009]
Furthermore, in an aqueous solution having a low oxidizing property, an active hydrophobic silicon surface is likely to be exposed, and it is difficult to remove attached particles on such a surface. For example, when polishing particles attached to the wafer surface are removed by sponge scrubber processing after CMP of Poly-Si, more polishing particles remain on the Poly-Si surface than on the surface of the silicon oxide film used as a CMP stopper. Cheap.
[0010]
Therefore, at present, as described in, for example, JP-A-7-263430, H₂  O₂  Aqueous solution or O₃  Washing is performed by mixing dissolved water and increasing the oxidation potential. When silicon is washed with such a liquid, the silicon surface is covered with a thin natural oxide film, and the natural oxide film is slowly etched. Therefore, when the wafer is cleaned, a large amount of silicon exposed on the wafer surface is not etched or the surface is not roughened. Further, since the surface becomes a hydrophilic surface, abrasive particles are efficiently removed from the Poly-Si surface during cleaning after the Poly-Si CMP.
[0011]
But H₂  O₂  In order for the catholyte mixed with the aqueous solution to have a sufficient oxidizing power, it is necessary to raise the temperature of the solution. This is because H₂  O₂  This is because the decomposition reaction proceeds. Also O₃  In the catholyte mixed with dissolved water, the mixing part of the liquid and the cathode water generating part are separated, despite the fact that the redox potential and pH of the liquid change due to the mixing. It is difficult to control precisely.
[0012]
In addition, when electrolytic ionic water is used for cleaning semiconductor elements, corrosion of the anode during electrolytic ionic water generation is a problem. The anode is usually formed of a noble metal such as Pt, carbon, or the like. If the oxidation potential is too high or a solution with an excessively low pH is generated by electrolysis, the anode is made of a material that is not easily corroded. Corroded gradually. This corrosion causes time-dependent changes in the electrolysis, metal contamination of the device, and deterioration of the electrical characteristics of the device. On the other hand, such corrosion is unlikely to occur at the cathode, but a solution having a high reducing power is generated near the cathode.If metal ions are mixed in the solution for electrolysis, the metal ions adhere to the cathode. Cheap. When the contaminant metal adheres to the electrode as described above, the adhered metal may elute again in the liquid and contaminate the sample due to a change with time of the electrolysis reaction.
[0013]
As described above, in general, anode water is useful for cleaning contaminated metals, but there is a problem that removal of some metals such as Fe becomes difficult due to high oxidation potential. Was.
[0014]
Cathode water is also useful for removing particles.However, there is a problem that metal mixed in the solution adheres to the sample surface as a hydroxide or contaminated metal on the sample surface remains. When the sample with the exposed silicon was washed, there were problems that a large amount of silicon was etched, the silicon surface was roughened, and particles attached to the silicon surface were difficult to remove.
[0015]
These problems stem from the fact that there is a correlation between the change in the pH and the oxidation-reduction potential generated in the reaction for producing electrolytic ionic water. Therefore, in order to solve the problem, it is necessary to independently optimize the pH and the oxidation-reduction potential of the electrolytic ionized water.
[0016]
In addition, when electrolysis is performed, the corrosion of the anode causes metal contamination of the sample and changes over time in the electrolysis, and the contaminated metal mixed in the solution adheres to the cathode, and the adhered metal is eluted again and the sample is removed. Had the problem of contaminating.
[0017]
[Problems to be solved by the invention]
The present invention has been made to solve the conventional problems, and the first object of the present invention is to independently optimize the pH and the oxidation-reduction potential without causing surface roughness and adhesion of contaminant metals. It is an object of the present invention to provide a method for manufacturing a good semiconductor device safely and easily by using a simplified processing solution.
A second object of the present invention is to provide an apparatus for safely and easily producing a processing solution containing no contaminants or the like and having optimized pH and oxidation-reduction potential.
[0018]
[Means for Solving the Problems]
In the first aspect of the present invention, a reducing gas supply step of immersing an anode and a cathode in a solution with a diaphragm interposed therebetween to supply a reducing gas to the solution near the anode, and oxidizing the solution to a solution near the cathode A semiconductor using a processing liquid obtained by performing at least one gas supply step of an oxidizing gas supply step of supplying an oxidizing gas, energizing the anode and the cathode, and electrolyzing the solution. An apparatus manufacturing method is provided.
[0019]
Secondly, the present invention provides a container body for holding a solution, a partition wall for dividing the container body into two regions, an anode and a cathode which are respectively immersed in the solution in the two regions, At least one of a reducing gas supply means for supplying a reducing gas to the vicinity of the anode and an oxidizing gas supply means for supplying an oxidizing gas to the vicinity of the cathode, and electricity is supplied between the anode and the cathode. And a means for generating a processing liquid.
[0020]
Thirdly, the present invention thirdly arranges the anode and the cathode by immersing them in a solution with a diaphragm interposed therebetween, and at least one of an oxidizing gas and a reducing gas is added to a solution near one of the anode and the cathode. Supplying and conducting a current between the anode and the cathode to perform a method of manufacturing a semiconductor device using a processing solution obtained by electrolyzing the solution, wherein at least one of the anode and the cathode is a gas. To provide a method for manufacturing a semiconductor device including a gas-permeable member that selectively permeates a solution into a solution.
[0021]
Fourth, the present invention provides a container body for holding a solution, a partition wall for dividing the container body into two regions, an anode and a cathode each immersed in the solution in the two regions, An apparatus for producing a processing liquid, comprising: a gas supply unit for supplying one of a reducing gas and an oxidizing gas to a vicinity of one of an anode and a cathode; and a unit for supplying a current between the anode and the cathode. Further, there is provided an apparatus for generating a processing liquid, wherein at least one of the anode and the cathode includes a gas-permeable member that selectively allows gas to pass through a solution.
[0022]
Fifth, the present invention provides a first and a second region separated by a first diaphragm at least partially composed of a cation exchange membrane and a second partition at least partially composed of an anion exchange membrane; The first, second, and third solutions are contained in the first, second, and third solutions contained in the respective regions of the container divided into the third region located between the first and second regions. After immersing and arranging the electrodes, applying different potentials to the three electrodes, and electrolyzing the solution, a method for manufacturing a semiconductor device using the processing solution obtained from the third region is described. provide.
[0023]
Sixth, the present invention provides a container body for holding a solution, and at least one part which is disposed in the container body and divides the inside of the container body into first, second, and third regions. A membrane consisting of the membrane and a membrane consisting at least in part of the anion exchange membrane, respectively immersed in the first, second and third solutions contained in the first, second and third regions, respectively; And a means for applying a different potential to each of the first, second, and third electrodes, and a means for applying different potentials to the first, second, and third electrodes.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is roughly divided into first to sixth aspects.
According to the first aspect of the present invention, an anode and a cathode are immersed in a solution with a diaphragm interposed therebetween, and a reducing gas is supplied to the solution near the anode or an oxidizing gas is supplied to the solution near the cathode. A method for manufacturing a semiconductor device using a processing solution obtained by supplying a solution or performing both of these processes, conducting a current between an anode and a cathode, and electrolyzing the solution is provided.
[0025]
According to a second aspect of the present invention, there is provided an apparatus for generating a processing liquid according to the first aspect. This apparatus comprises a container main body for holding a solution, a partition for dividing the container main body into two regions, an anode and a cathode each immersed in the solution in each region, and a reducing gas in the vicinity of the anode. It is provided with a reducing gas supply means for supplying, or an oxidizing gas supply means for supplying an oxidizing gas near the cathode, and a means for supplying electricity between the anode and the cathode.
[0026]
The anode or cathode preferably includes a gas permeable member that selectively allows gas to pass through the liquid.
The reducing gas refers to a gas that acts on a gas, a liquid, or a solid and easily gives its own electrons to them. Such gases include, for example, hydrogen gas, carbon monoxide gas, and nitric oxide.
[0027]
The oxidizing gas refers to a gas that acts on a gas, a liquid, or a solid to easily remove electrons from the gas, the liquid, or the solid. Such gases include oxygen gas, ozone gas, fluorine gas, chlorine gas, bromine gas, iodine gas, halogen oxide gas, interhalogen gas, halogenated rare gas, and hydrogen peroxide gas.
[0028]
Examples of the solution to be subjected to electrolysis include pure water, hydrochloric acid, aqueous ammonia, carbonic acid, aqueous hydrogen peroxide, and aqueous solutions of ammonium salts such as ammonium chloride.
Further, as the diaphragm, a film that suppresses the mixing of the solution on the anode side and the solution on the cathode side, that is, a film that suppresses the mixture of cations and anions, for example, an ion-exchange resin film can be used. In addition, each of the anode and the cathode may be singular or plural.
[0029]
According to the present invention, the pH and the oxidation-reduction potential of the anode water and the cathode water can be controlled independently. For example, when a small amount of oxidizing gas is introduced near the cathode or a reducing gas is introduced near the anode, the introduced gas is H, H generated near the electrode.₂  And O, O₂  , O₃  Thus, cathodic water having a high pH but not a high reduction potential, and anodic water having a low pH and a low oxidation potential can be obtained. Further, if the amount of the oxidizing gas or the reducing gas introduced is increased, cathode water having a high oxidation potential or anode water having a high reducing potential can be generated.
[0030]
Accordingly, it is possible to generate a cleaning liquid having a pH and an oxidation-reduction potential optimum for a contaminated metal or a member exposed on the surface of the sample, a cleaning liquid for removing the film, a polishing liquid for CMP, and a cleaning liquid that does not deposit metal oxide and the like. . When such a solution is used, for example, in a cleaning process in a semiconductor device manufacturing process, it is necessary to effectively remove contaminant metals on the surface of the semiconductor substrate, and to clean the semiconductor substrate without contaminating the metal with the metal or causing surface roughness. In addition, particles attached to the surface can be effectively removed. In addition, since it is not necessary to create a cleaning solution having an unnecessarily high concentration, it is possible to reduce the amount of chemicals and power consumed during the generation of the cleaning solution and the detoxification process, the amount of waste discharged after the detoxification process, and the like. , It is possible to make effective use of earth resources.
[0031]
In a method according to a third aspect of the present invention, there is provided a method of manufacturing a semiconductor using another electrolysis process different from the electrolysis process of the method according to the first aspect.
[0032]
In this method, an electrode including a gas-permeable member that selectively allows gas to pass through a solution is prepared, and this electrode is used as at least an anode or a cathode, and the anode and the cathode are immersed in the solution with a diaphragm interposed therebetween. The oxidizing gas or the reducing gas is supplied to the solution through the gas-permeable member, and a current is applied between the anode and the cathode to electrolyze the solution to obtain a processing solution for the semiconductor device. Applies to manufacturing.
[0033]
According to a fourth aspect of the present invention, there is provided an apparatus for generating a treatment liquid used in the third aspect. The apparatus comprises a container body for holding the solution, a partition for dividing the container body into two regions, an anode and a cathode which are respectively immersed in the solution in the two regions, and an anode and a cathode. In the vicinity of one of them, a gas supply means for supplying one of the reducing gas and the oxidizing gas, and a means for conducting electricity between the anode and the cathode, and at least one electrode of the anode and the cathode is provided. , A gas permeable member that selectively allows gas to pass through the solution.
[0034]
In this method, a gas-permeable member that allows gas to permeate but does not allow liquid to permeate is used for at least a part of at least one electrode. The gas generated by electrolysis may be removed through the gas permeable member, or an oxidizing gas or a reducing gas may be supplied to a solution near the electrode.
[0035]
As described above, if a gas permeable member is used for the anode and the cathode, and an oxidizing gas or a reducing gas is supplied through the gas permeable member, the electrode and the gas supply means can be shared, so that The size can be reduced.
[0036]
In addition, for example, by efficiently removing excess oxidizing gas generated at the anode from the anode or by supplying a reducing gas to the anode, the oxidation potential of the solution near the anode can be appropriately reduced, thereby suppressing corrosion of the anode. it can.
[0037]
Furthermore, for example, by removing excess reducing gas generated at the cathode from the cathode or by supplying an oxidizing gas to the cathode appropriately, the oxidation potential of the solution near the cathode can be appropriately improved, so that it is mixed into the solution. Adhesion of the metal ions to the cathode can be suppressed, and sample contamination due to re-elution of the adhered metal can be prevented.
[0038]
According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor using still another electrolysis process different from the electrolysis process of the method according to the first aspect. In this method, a first membrane containing a cation exchange membrane and a second membrane containing an anion exchange membrane are separated from each other by a first membrane contained in an area divided into first, second, and third areas. Dissolving the first, second, and third electrodes in the second and third solutions, respectively, by applying different potentials to the three electrodes, respectively; To obtain electrolyzed water. The third region described above is located between the first and second diaphragms, and the first region is located across the first diaphragm, and the second region is located across the second diaphragm. In the present invention, the processing liquid obtained in the third region is applied to a semiconductor device.
[0039]
According to a sixth aspect of the present invention, there is provided an apparatus for generating a processing liquid used in the fifth aspect. The apparatus includes a container body that holds a solution, and a cation exchange membrane and an anion exchange membrane that are respectively disposed in the container body and divide the inside of the container body into first, second, and third regions. And first, second, and third electrodes respectively immersed in first, second, and third solutions contained in the first, second, and third regions, respectively. And means for applying different potentials to the first, second, and third electrodes, respectively.
[0040]
In the invention according to the fifth and sixth aspects, A is a potential applied to the first electrode, B is a potential applied to the second electrode, and C is a potential applied to the third electrode. The conditions shown in the following i) to iv)
i) the main cation in the first solution is one of an ammonium ion and an alkyl ammonium ion, the main anion in the second solution is a hydroxide ion, and A> C> B.
[0041]
ii) the primary cation of the first solution is one of an ammonium ion and an alkyl ammonium ion, where A> C and B> C.
iii) main cations in the first solution are hydrogen ions, and main anions in the second solution are halogen ions, hydrogen halide ions, halogen oxide ions, sulfate ions, nitrate ions, carbonate At least one selected from the group consisting of ions, phosphate ions, and hydrogen peroxide ions, where A> C> B.
[0042]
iv) the primary anion in the second solution is selected from the group consisting of a halogen ion, a hydrogen halide ion, a halogen oxide ion, a sulfate ion, a nitrate ion, a carbonate ion, a phosphate ion, and a hydrogen peroxide ion. A <C and B <C.
It is preferable that any one of the above is satisfied.
[0043]
FIG. 1 is a diagram showing the range of the pH and the oxidation-reduction potential of the treated water obtained under the conditions i) to iv). As shown, depending on the conditions i) to iv), treated water having a pH and an oxidation-reduction potential in the ranges indicated by 310, 320, 330 and 340 in the figure, respectively, can be obtained. For comparison, a graph 301 showing a relationship between the pH of the conventional electrolyzed water and the oxidation-reduction potential is shown in a graph 301. As shown in the figure, for example, under the condition iii), water having a lower pH and a lower oxidation potential than conventional electrolyzed water can be obtained. Such treated water is suitable for dissolving and removing Fe, for example. It should be noted that treated water having a pH and an oxidation-reduction potential in the range shown by i) and iii) in the first aspect and i) to iv) in the fourth aspect is obtained.
[0044]
Even with such a generation method and a generation apparatus, a solution in which pH and oxidation-reduction potential are independently controlled can be generated, and contaminant metal removal, film peeling, and CMP of a wafer can be efficiently performed. .
[0045]
【Example】
Hereinafter, the present invention will be specifically described with reference to the drawings.
FIG. 2 is a schematic diagram showing a first example of a processing liquid generation device according to the present invention.
In FIG. 2, an anode 12 and a cathode 13 are provided in a container 11 for holding an aqueous solution. Between the anode 12 and the cathode 13, a diaphragm 14 made of, for example, an ion exchange resin membrane is provided in order to suppress the mixing of the solution near these electrodes. In addition, inlets 15a and 15b and outlets 16a and 16b are provided in each area partitioned by the diaphragm 14 so that the solution can be independently introduced and discharged. The anode 12 is formed of a cylindrical gas-permeable member made of porous platinum that selectively allows gas to pass therethrough without passing a liquid. Part of the gas introduced into the cylinder is introduced into the solution through the porous platinum wall.
[0046]
The evaluation when the processing liquid generated by the above apparatus was used as a wafer cleaning liquid was evaluated as follows.
First, 24 silicon wafers (p-type (100), 0.01 Ω · cm) were prepared. This silicon wafer was immersed in pure water in which about 5 ppm of ozone was dissolved for 10 minutes to remove organic substances on the wafer surface.
[0047]
Next, using the apparatus shown in FIG. 2, a DC voltage of 100 V was applied between the anode and the cathode, and ammonium sulfate was dissolved (at a concentration of 1 × 10 4) to promote the electrolysis of water.^-3(mol / l) was introduced through the inlets 15a and 15b, and the solution discharged from the outlets 16a and 16b was held in another container. With respect to the solution discharged from the outlet 16a, the liquid when hydrogen gas is introduced into the cylinder of the anode 12 is referred to as a cleaning liquid 1-a, and the liquid when hydrogen gas is not supplied is referred to as a cleaning liquid 1-b. The pH of the cleaning solution 1-a and the cleaning solution 1-b were both about 4, and the redox potential was about 0.1 V for the former and about 1.0 V for the latter. The former has a low oxidation-reduction potential because OH or O generated on the anode surface is introduced H₂  Reacts with the gas to form H₂  This is because it changes to O.
[0048]
Next, eight of the 24 wafers were immersed in one of the cleaning liquids 1-a and 1-b for 10 minutes, rinsed with pure water, and dried with a spin drier. The wafers cleaned with the cleaning liquid 1-a and the cleaning liquid 1-b and the wafers not cleaned with these liquids are referred to as type A1, type B1, and type C1, respectively.
[0049]
Next, the wafers of these types A1, B1, and C1 were all split in half, and for one of them, the concentration of metal contamination on the surface was analyzed by an atomic absorption method. The remaining wafer is heated to about 950 ° C. in dry oxygen to form a thermal oxide film having a thickness of about 5 nm, and a 0.5 μm-thick phosphorus-doped polycrystalline silicon film is further deposited thereon and patterned. Then, a MOS capacitor was formed.
[0050]
From the analysis of metal contamination, about 1 × 10¹⁰atoms / cm²  , Fe is about 6 × 10⁹  atoms / cm²  was detected. Further, in the type B1 wafer, Al is the detection limit (1 × 10⁹  atoms / cm²  ), But Fe was about 1.5 × 10⁹  atoms / cm²  was detected. On the other hand, in the type A1 wafer, not only Al but also Fe can be detected (8 × 10⁸  atoms / cm²  )
[0051]
Also, when the dielectric breakdown voltage of the oxide film of the MOS capacitor was evaluated, the percentage of the total capacitor having a breakdown voltage of 8 MV / cm or more was about 98% for the type A1 wafer, about 92% for the type B1, and about 92% for the type B1. C1 was about 85%.
[0052]
Thus, by cleaning with the cleaning liquid according to the present invention, the concentration of contaminating Fe on the silicon wafer surface can be reduced, and by performing cleaning with the cleaning liquid according to the present invention before thermal oxidation of the silicon substrate, the dielectric breakdown voltage can be reduced. A high thermal oxide film could be formed.
[0053]
In the apparatus shown in FIG. 2, the entire cylinder constituting the anode is made of porous platinum and functions as a gas permeable member. However, at least a part of the cylinder is made of porous platinum or the like and functions as a gas permeable member. Just fine. The permeable member only needs to have conductivity and gas permeability, and the permeable member may be formed using a porous noble metal such as porous graphite or iridium.
[0054]
FIG. 3 is a schematic view showing a second example of the processing liquid generating apparatus according to the present invention.
In FIG. 3, an anode 22 and a cathode 23 are provided in a container 21 for holding an aqueous solution. Between the anode 22 and the cathode 23, in order to prevent mixing of the solution near these electrodes, for example, a diaphragm made of an ion exchange resin membrane is used. 24 are installed. In addition, inlets 25a and 25b and outlets 26a and 26b are provided in each area partitioned by the diaphragm 24 so that the solution can be introduced and discharged independently. In the vicinity of the anode 22, a number of gas introducing cylinders 27 each of which is formed of a gas permeable membrane that selectively allows gas to pass therethrough without passing a liquid, are disposed. The gas introduced into the gas introducing cylinder 27 passes through the gas permeable membrane. Through the anode 22.
[0055]
In order to evaluate the processing liquid generated by the above apparatus as a wafer cleaning liquid, the MOS capacitor and the metal impurity analysis wafer were evaluated in the same manner as in the first embodiment.
[0056]
First, 24 silicon wafers (p-type (100), 0.01 Ω · cm) were prepared and immersed in pure water in which about 5 ppm of ozone was dissolved for 10 minutes to remove organic substances on the wafer surface.
[0057]
Next, using the apparatus shown in FIG. 3, a DC voltage of 100 V was applied between the anode and the cathode, and ammonium sulfate was dissolved (at a concentration of 1 × 10 4) to promote the electrolysis of water.^-3(mol / l) was introduced through the inlets 25a and 25b, and the solution discharged from the outlets 26a and 26b was held in another container. With respect to the solution discharged from the discharge port 26a, a liquid when hydrogen gas is introduced into the gas introduction cylinder 27 is referred to as a cleaning liquid 2-a, and a liquid when hydrogen gas is not supplied is referred to as a cleaning liquid 2-b. The pH of the cleaning solution 2-a and the cleaning solution 2-b were both about 4, and the redox potential was about 0.3 V for the former and about 1.0 V for the latter. The former has a low oxidation-reduction potential because OH or O generated on the anode surface is introduced H₂  Reacts with the gas to form H₂  This is because it changes to O.
[0058]
Next, eight of the 24 wafers were immersed in one of the cleaning liquid 2-a and the cleaning liquid 2-b for 10 minutes, rinsed with pure water, and dried with a spin drier. The wafers cleaned with the cleaning liquids 2-a and 2-b and the wafers not cleaned with these liquids are referred to as type A2, type B2, and type C2 wafers, respectively.
[0059]
Next, the type A2, B2, and C2 wafers were all folded in half, the metal contamination concentration on the surface was analyzed for one of them, and the MOS wafer was manufactured for the remaining wafers in the same steps as those described in the first embodiment. .
[0060]
The degree of metal contamination of the wafers of types B2 and C2 is the same as in the first embodiment. In the former, Al is the detection limit (1 × 10⁹  atoms / cm²  ) Below, but Fe is about 1.5 × 10⁹  atoms / cm²  In the latter, Al is about 1 × 10¹⁰atoms / cm²  And Fe is about 6 × 10⁹  atoms / cm²  was detected. On the other hand, in the type A2 wafer, Al is below the detection limit and Fe is 1 × 10⁹  atoms / cm²  Met.
[0061]
Also, when the dielectric breakdown voltage of the oxide film of the MOS capacitor was evaluated, the percentage of the total capacitor having a breakdown voltage of 8 MV / cm or more was about 94% for the type A2 wafer, about 91% for the type B2, and about 91% for the type B2. C2 was about 83%.
[0062]
Thus, by cleaning with the cleaning liquid according to the present invention, the concentration of contaminating metals on the surface of the silicon wafer can be reduced, and by performing cleaning with the cleaning liquid according to the present invention before thermal oxidation of the silicon substrate, the dielectric breakdown voltage can be reduced. , A thermal oxide film having a high density could be formed.
[0063]
FIG. 4 is a diagram illustrating a third example of the processing liquid generation device according to the present invention.
As shown in FIG. 4, the container 31 is divided into three chambers of an anode chamber 31a, a cathode chamber 31b and an intermediate chamber 31c by diaphragms 34a and 34b, and each chamber has a solution inlet 35a, 35b and 35c, and an outlet, respectively. 36a, 36b and 36c are provided. The anode chamber 31a is provided with an anode 32, and the cathode chamber 31b is provided with a cathode 33. The intermediate chamber 31c is filled with an ion exchange resin for promoting the dissociation of water. H generated on the surface of this ion exchange resin⁺  And OH⁻  Is diffused to the anode 32 in the anode chamber 31a and the cathode 33 in the cathode chamber 31b, and electrons are transferred between these electrode surfaces, so that water electrolysis can be performed efficiently.
[0064]
Evaluation of the processing liquid generated by the above apparatus as a cleaning liquid for a wafer was performed as follows.
First, 24 silicon wafers (p-type (100), 0.01 Ω · cm) were prepared, and 12 of them were subjected to lithography and plasma etching using chlorine gas to have an opening diameter of 0.5 μm and a depth of 3 μm. A trench was formed. For the remaining 12 wafers, the entire surface was subjected to plasma etching under the same conditions as those for forming the trenches. Thereafter, the wafer was immersed in pure water in which about 5 ppm of ozone was dissolved for 10 minutes to remove organic substances on the wafer surface.
[0065]
Next, using the apparatus of FIG. 4, a DC voltage of 50 V was applied between the anode 32 and the cathode 33, and 1 × 10^-3An aqueous solution of ammonium chloride having a concentration of mol / l was introduced from the inlets 35a, 35b and 35c, and the solutions discharged from the outlets 36a, 36b and 36c were held in another container. A solution obtained by dissolving about 3 ppm of ozone gas in the solution discharged from the outlet 36b is introduced into the inlet 35c as a cleaning solution 3-a. The pH of the cleaning liquid a and the cleaning liquid b were both about 12, and the oxidation-reduction potential was about +0.7 V for the former and about -0.7 V for the latter. The former having a high oxidation-reduction potential is because an aqueous solution having a high ozone concentration is diffused from the intermediate chamber 31c to the cathode 33 of the cathode chamber 31b, and H or H generated on the electrode surface is formed.₂  Etc. H₂  This is because O was changed to O.
[0066]
Next, four wafers were respectively immersed in the cleaning solution 3-a and the cleaning solution 3-b for 10 minutes for each of the wafer having the trenches formed therein and the wafer having no trenches formed therein, rinsed with pure water, and then dried with a spin drier. . The purpose of this process is to remove the damaged layer and the contaminated layer inside the Si wafer and the particles attached to the wafer surface generated by the plasma etching by etching the Si with an alkaline liquid. The wafers cleaned with the cleaning liquid 3-a and the cleaning liquid 3-b and the wafers not cleaned with these cleaning liquids are referred to as wafers having a trench formed therein as type A3, type B3, and type C3 wafers. The unprocessed wafers will be referred to as type A3 ', type B3', and type C3 'wafers.
[0067]
For the wafers of types A3 ', B3', and C3 ', surface metal contamination analysis was performed by the atomic absorption method. As a result, about 5 × 10 Cr was obtained from the type C3 ′ wafer.¹⁰atoms / cm²  was detected. In the type B3 ′ wafer, Cr is about 5 × 10⁹  atoms / cm²  Met. On the other hand, in the type A4 wafer, the detection limit of Cr (1 × 10⁹  atoms / cm²  )
[0068]
Next, in order to evaluate the etching amount of silicon in the trench portion caused by cleaning with the cleaning liquid and the unevenness of the inner surface of the trench after the etching, a part of the type A3, B3, and C3 wafers was analyzed by TEM and AFM. did. As a result, the etching depth and the average surface roughness were about 3 nm and about 1 nm, respectively, for the type A3 wafer, and about 15 nm and about 8 nm, respectively, for the type B3 wafer. The etching depth and surface roughness of the type A3 wafer cleaned by the cleaning liquid 3-a are small because, in the cleaning liquid 3-a containing ozone gas, the silicon surface is relatively uniformly oxidized while removing contaminant organic substances and the like, and at the same time, OH⁻  This is because the silicon oxide film is slowly etched by the ions. On the other hand, when cleaning is performed with a highly reducing cleaning solution 3-b such as a type B3 wafer, contaminated organic matter remains on the surface, and the exposed silicon surface is directly exposed to OH.⁻  Since the etching is performed by the ions, the silicon is rapidly and non-uniformly etched.
[0069]
Next, the remaining trench-formed wafer analyzed was heated to about 950 ° C. in dry oxygen to form a thermal oxide film of about 5 nm, and a 0.5 μm-thick phosphorus-doped polycrystalline silicon film was further formed thereon. This was deposited and patterned to form a MOS capacitor. When the withstand voltage of the oxide film of the MOS capacitor was evaluated, the percentage of the total capacitor having a withstand voltage of 8 MV / cm or more was about 95% for the type A3 wafer, about 88% for the type B3 wafer, and about 88% for the type B3 wafer. The C3 wafer was about 50%.
[0070]
As described above, by cleaning with the cleaning liquid according to the present invention, the concentration of contaminating Cr on the silicon wafer surface can be reduced, and by performing this cleaning before the thermal oxidation of the silicon trench, the surface roughness can be substantially reduced. Thus, the RIE damaged layer on the inner wall of the trench could be removed, and a thermal oxide film having a high dielectric breakdown voltage could be formed.
[0071]
Next, a fourth example of the present invention will be described. In this embodiment, the apparatus shown in FIG. 2 is used.
In this example, a wafer is cleaned in the manufacture of a semiconductor device.
[0072]
First, nine silicon wafers (p-type (100), 0.01 Ω · cm) are prepared and immersed in pure water containing about 5 ppm of ozone for 10 minutes to remove organic substances on the wafer surface.
[0073]
Next, while applying a DC voltage of 50 V between the anode 12 and the cathode 13 in the apparatus shown in FIG.^-2(mol / l) was introduced from the inlets 15a and 15b, and the solution discharged from the outlets 16a and 16b was held in another container. With respect to the solution discharged from the outlets 16a and 16b, a liquid when a small amount of hydrogen gas is introduced into the cylinder of the anode 12 is referred to as a cleaning liquid 4-a, and a liquid when the hydrogen gas is not introduced is referred to as a cleaning liquid 4-b. The pH of the washing solution 4-a and the washing solution 4-b were both 1.5, and the oxidation-reduction potential was about 0.9 V and about 1.3 V, respectively. The former has a low oxidation-reduction potential because OH or O generated on the surface of the anode 32 is introduced H₂  Reacts with the gas to form H₂  This is because it changes to O or the like.
[0074]
Next, three of the nine wafers were immersed in one of the cleaning liquid 4-a and the cleaning liquid 4-b for 10 minutes, rinsed with pure water, and dried with a spin dryer. The wafers cleaned with the cleaning liquids 4-a and 4-b and the wafers not cleaned with these liquids are referred to as type A4, type B4, and type C4 wafers, respectively.
[0075]
Next, the concentration of metal contamination on the surfaces of these types A4, B4 and C4 wafers was analyzed by atomic absorption spectrometry. As a result, from the wafer of type C4, Al¹⁰atoms / cm²  , Fe is about 1 × 10¹⁰atoms / cm²  Detected (average of three images). Pt was below the detection limit. In the case of the type B4 wafer, two of the three measured wafers have a detection limit of Al, Fe, and Pt (Al: 1 × 10⁹  atoms / cm²  , Fe: 8 × 10⁸  cm / atoms, Pt: 1 × 10⁹  atoms / cm²  ) Pt was about 3 × 10 from one wafer⁹  atoms / cm²  was detected. On the other hand, in the type A4 wafer, all of Al, Fe and Pt were below the detection limit.
[0076]
As described above, since the cleaning liquids 4-a and 4-b have a low pH and a high oxidation potential, metal contamination such as Fe and Al on the wafer surface can be removed. However, Pt is detected from the wafer cleaned with the cleaning liquid 4-b. Since Pt has not been detected from the wafer before cleaning, it is presumed that this Pt is caused by the cleaning liquid 4-b. This is because a liquid having a lower pH and a higher oxidation potential than the cleaning solution itself is generally generated at the anode, so that when the cleaning solution 4-b having a low pH and a high oxidation potential is generated, a very low pH is generated near the anode 12. It is considered that a liquid having an extremely large oxidation potential was generated, and Pt which was hardly corroded was etched. In addition, when the cleaning solution 4-a was generated, since hydrogen gas was introduced into the solution from the inside of the cylinder of the anode 12, the oxidation potential of the solution in the vicinity of the anode 12 was suppressed to some extent, and the anode 12 did not corrode. Conceivable.
[0077]
In each of the above embodiments, one anode and one cathode may be provided, but at least one of the anode and the cathode may be provided in plurality.
As a method for introducing gas into the vicinity of the electrode, a member having gas permeability is used for the wall of the container or the like, and a gas is introduced through the wall, or a solid such as silver oxide that easily releases oxygen is placed near the electrode. It is also possible to use a method in which a voltage is applied to the solid to release oxygen by applying a voltage to the solid, a space is provided in the container so as to be in contact with the solution, and a gas flows in the space.
[0078]
In the above example, the oxidation-reduction potential of the solution is changed by introducing a gas into the solution from the outside. Can be controlled. As a method of removing gas from the solution, a method of using a gas permeable member on a part of the container wall and exhausting from the member, or a method of removing the inside of the anode 12 in FIG. There is a method of reducing the pressure. Since the pH and the oxidation-reduction potential of the solution prepared by the above-described method are independently controlled, the solution can be used for purposes other than cleaning, for example, film peeling or CMP slurry.
[0079]
FIG. 5 is a schematic diagram of a processing liquid generating apparatus used in a fifth example according to the present invention. FIG. 6 shows a schematic diagram of a conventional cleaning liquid generation device for comparison. The silicon wafer was cleaned with the cleaning liquid generated by the apparatus shown in FIGS. 5 and 6, and the cleaning effects were compared.
[0080]
First, in the apparatus shown in FIG. 5, the inside of the container 601 is divided into three regions by a cation exchange membrane 611 and an anion exchange membrane 612, and a liquid inlet 621, 622, 623 and a liquid outlet 631, 632, 633 allows the introduction and discharge of liquid for each area. Further, each of the regions is provided with electrodes 641, 642, 643, and by flowing a current between these electrodes, the liquid introduced into each region can be electrolyzed.
[0081]
In this apparatus, a very small amount (2 × 10 5) of HCl was used as a supporting electrolyte in the inlet 621 and the inlet 622.^-5mol / l), and an aqueous solution of ammonium chloride was dissolved (2 × 10^-3mol / l) were introduced, and 0 V, 50 V, and 30 V potentials were applied to the electrodes 641, 642, and 643, respectively, to electrolyze the aqueous solution, and the liquid discharged from the outlet 632 was used for washing. .
[0082]
Here, on the surface of each electrode, the following reactions mainly occur according to the respective potential differences.

In addition, the following ion movement occurs in the cation exchange membrane 611 and the anion exchange membrane depending on the direction of the electric field and the ion species in the liquid.
[0083]
Cation exchange membrane: H⁺  From the electrode 642 side to the electrode 641 side
Anion exchange membrane: Cl⁻  From the electrode 643 side to the electrode 642 side
Therefore, by the electrolysis reaction and the ion transfer occurring between the electrode 642 and the electrode 643, the H of the region where the electrode 642 is set⁺  , O₂  , O₃  , HClO_x  Etc. increase in concentration. This means the production of a liquid having a low pH and a high oxidation potential. On the other hand, by the electrolysis reaction and ion transfer occurring between the electrode 642 and the electrode 641, O₂  O₃  , The concentration increases, but H⁺  The concentration hardly changes (H on the surface of the electrode 642).⁺  Is generated, but H reaches the region where the electrode 841 is installed.⁺  By moving). This means the generation of a liquid having a high oxidation potential.
[0084]
From the above, it can be seen that the liquid discharged from the outlet 632 has a lower pH and a higher oxidation potential than the liquid introduced from the inlet 622. When the pH and the oxidation-reduction potential of the liquid discharged from the outlet 632 were measured, the pH was 6 and the oxidation-reduction potential was 0.85 V.
[0085]
In the conventional apparatus shown in FIG. 6, the inside of the container 701 is divided into two regions by an anion exchange membrane 712, and liquid introduction ports 721, 722 and discharge ports 731, 732 allow the liquid to be supplied to each region. Inlet and discharge can be performed. Further, each region is provided with an electrode (electrodes 741 and 742), and by flowing a current between these electrodes, it is possible to electrolyze the liquid introduced into each region.
[0086]
Here, a very small amount of HCl (2 × 10^-5mol / l) and an aqueous ammonium chloride solution (2 × 10^-3mol / l), and a potential of 50 V or 30 V is applied to each of the electrodes 741 and 742 to electrolyze the aqueous solution. The solution discharged from the outlet 731 is used for washing.
[0087]
Here, on the surface of each electrode, the following reactions mainly occur according to the respective potential differences.

Further, since the electrode 741 has a higher potential than the electrode 742, the electrode 741 has Cl⁻  Moves from the electrode 742 side to the electrode 741 side.
[0088]
Since such a reaction occurs, the liquid discharged from the outlet 731 is higher in H than the liquid introduced from the inlet 721.⁺  , Cl⁻  , O₂  O₃  The concentration increases. When the pH and the oxidation-reduction potential of the liquid discharged from the outlet 731 were actually measured, the pH was 6 and the oxidation-reduction potential was 0.65 V.
[0089]
Next, in order to examine the cleaning effect of the cleaning solution generated in FIGS. 5 and 6, the natural oxide film on the surface was removed with hydrofluoric acid and then intentionally contaminated with Cu (about 1 × 10¹¹atoms / cm²  3) Each of the cleaned silicon wafers was washed with these liquids. After washing, HF / H₂  O₂  The residual Cu on the surface was recovered by the liquid, and the recovered liquid was analyzed by ICP-mass spectrometry. The Cu concentration of the three wafers cleaned with the cleaning liquid in FIG.⁹  atoms / cm²  6) On the other hand, the wafer washed with the liquid generated by the apparatus of FIG.¹⁰atoms / cm²  (Average value of three sheets) Cu was detected.
[0090]
The reason why the cleaning efficiency of Cu differs as described above can be explained with reference to the drawings. FIG. 7 shows a pH-redox potential equilibrium diagram of Cu. In the figure, Cu²⁺The boundary line between Cu and Cu is a dashed line for Cu attached on Si having a higher reducing property than Cu as in the case of the above-mentioned contamination, and is a solid line when Cu is attached on the Cu surface with low reducing property, for example. Is represented by In this figure, the positions corresponding to the pH-oxidation-reduction potential of the cleaning liquid generated in FIGS. 5 and 6 are indicated by white circles and black circles. From this figure, it can be seen that the cleaning liquid having a high oxidation potential and produced in FIG.²⁺The cleaning solution generated in FIG. 6 has a relatively low oxidation potential while being in the equilibrium region of Cu, while it is in the equilibrium region of Cu. It turns out that you can't.
[0091]
As described above, by using the present invention, it is possible to generate a cleaning liquid having a higher oxidation potential than before, and it is possible to efficiently remove contaminated Cu on the wafer surface. Such a liquid having a high oxidation potential can also be used for removing organic contaminants on the sample surface, removing organic thin films such as resist, and stabilizing the surface of silicon or the like by forming a natural oxide film. In the above embodiment, the inlet 623 has Cl⁻  Was used, but F⁻  Halogen ions such as HF₂  ⁻  Hydrogen halide ions such as ClO_x  ⁻  , BrO_x  ⁻  , IO_x  ⁻  Halogen oxide ions such as SO_x  ^2-, NO_x  ⁻  , PO_x  ^3-, HO₂  ⁻  A similar liquid can be produced by using a liquid containing the same.
[0092]
FIG. 8 is a schematic diagram of a cleaning liquid generation device used in a sixth example according to the present invention. In addition, the apparatus shown in FIG. 6 was also used for comparison. The silicon wafer was cleaned with the cleaning liquid generated by this apparatus, and the cleaning effects were compared. The device shown in FIG. 8 has the same basic configuration as the device shown in FIG. 5, except that the potential applied to the electrodes and the solution to be introduced are only partially different. First, the configuration of the apparatus in FIG. 8 and a method for generating a cleaning liquid using the apparatus will be described below.
[0093]
In the apparatus shown in FIG. 8, the inside of the container 901 is divided into three regions by a cation exchange membrane 911 and an anion exchange membrane 912, and the liquid is introduced by inlets 921, 922, 923 and outlets 931, 923, 933. The liquid can be introduced and discharged for each area. Further, each region is provided with an electrode (electrodes 941, 942, 943), and by flowing a current between these electrodes, it is possible to electrolyze the liquid introduced into each region.
[0094]
In this example, a very small amount of HCl (2 × 10 5) is used as a supporting electrolyte in the inlets 921 and 922 of the apparatus.^-5mol / l), and an aqueous ammonium chloride solution (2 × 10^-3(mol / l), and a potential of 100 V, 50 V, or 40 V was applied to each of the electrodes 941, 942, and 943 to electrolyze the aqueous solution. The solution discharged from the outlet 932 was used for washing.
[0095]
Here, on the surface of each electrode, the following reactions mainly occur according to the respective potential differences.

In addition, ions move as follows in the cation exchange membrane 911 and the anion exchange membrane 912 according to the direction of the electric field and the ion species in the liquid.
[0096]
Cation exchange membrane: H⁺  From the electrode 941 side to the electrode 942 side
Anion exchange membrane: Cl⁻  From the electrode 943 side to the electrode 942 side
Therefore, the electrolysis reaction and the ion transfer that occur between the electrode 942 and the electrode 943 cause the H of the region where the electrode 942 is installed to be H.⁺  , O₂  O₃  , HClO_x  Etc. increase in concentration. This means the production of a liquid having a low pH and a high oxidation potential. The electrolysis reaction and the ion transfer that occur between the other electrode 942 and the electrode 941 cause the H of the region where the electrode 942 is installed to be H.₂  The concentration increases, but H⁺  The concentration hardly changes. This is because H⁺  Reaction occurs, but H from the region where the electrode 941 is installed⁺  Moved and decreased H⁺  By supplementing. Thus, H₂  The concentration increases and H⁺  Since the concentration does not change, a liquid having a low oxidation potential is generated.
[0097]
From the above, the liquid discharged from the outlet 932 is lower in pH than the liquid introduced from the inlet 922, and the change in the oxidation-reduction potential is determined by the current flowing between the electrodes 942 and 941 and the electrode 942. It can be seen that the magnitude is determined by the magnitude relationship with the current flowing between the electrodes 943.
[0098]
In this example, reflecting the difference in the potential difference, the oxidation potential decreased because more current flowed between the former electrodes than between the latter electrodes. When the pH and the oxidation-reduction potential of the effluent from the outlet 932 were measured, the pH was 0 and the oxidation-reduction potential was almost 0 V.
[0099]
Further, a small amount of HCl (2 × 10 5) is introduced into the inlet 721 of the conventional apparatus shown in FIG.^-5mol / l) and an aqueous ammonium chloride solution (2 × 10^-3(mol / l), and a potential of 90 V or 0 V was applied to each of the electrodes 741 and 742 to electrolyze the aqueous solution. The solution discharged from the outlet 731 was used for washing.
[0100]
Here, on the surface of each electrode, the following reactions mainly occur according to the respective potential differences.

Further, since the electrode 741 has a higher potential than the electrode 742, the electrode 741 has Cl⁻  Moves from the electrode 742 side to the electrode 741 side.
[0101]
Since such a reaction occurs, the liquid discharged from the outlet 731 is higher in H than the liquid introduced from the inlet 721.⁺  , Cl⁻  , O₂  , O₃  Increase. When the pH and the oxidation-reduction potential of the liquid discharged from the outlet 732 were actually measured, the pH was 0 and the oxidation-reduction potential was 1.5 V.
[0102]
Next, in order to examine the cleaning effect of the cleaning liquid generated by the apparatus shown in FIG. 6 and the apparatus shown in FIG. 8, the surface was contaminated with Ti (about 5 × 10¹⁰atoms / cm²  3) Each of the cleaned silicon wafers was washed with these liquids.
[0103]
After the washing, residual Ti on the surface was recovered with an HF solution, and the recovered solution was analyzed by ICP-mass spectrometry. As a result, the Ti concentration of the wafer cleaned with the cleaning liquid of FIG.⁹  atoms / cm²  On the other hand, three wafers averaged about 4 × 10¹⁰atoms / cm²  Of Ti was detected.
[0104]
The reason why the cleaning efficiency of Ti is different will be described with reference to FIG. FIG. 9 is a pH-redox potential equilibrium diagram of Ti. In FIG. 9, the positions corresponding to the pH and the oxidation-reduction potential of the cleaning liquid generated in FIGS. 8 and 6 are indicated by white circles and black circles. From this figure, it can be seen that the cleaning liquid having a high oxidation potential and produced in FIG.₂  , The Ti on the wafer surface is hardly removed, while the oxidation potential is relatively low.₂  In the area of²⁺Part of Ti on the wafer surface²⁺It is considered to have dissolved.
[0105]
As described above, by using the present invention, a cleaning solution having a low pH and a low oxidation potential was generated, and the Ti on the wafer surface could be more efficiently removed than the cleaning solution generated by the conventional method. In the above embodiment, the inlet 923 is provided with Cl.⁻  Was used, but F⁻  Halogen ions such as HF₂  ⁻  Hydrogen halide ions such as ClO_x  ⁻  , BrO_x  ⁻  , IO_x  ⁻  Halogen oxide ions such as SO_x  ^2-, NO_x  ⁻  , PO_x  ^3-, HO₂  ⁻  A similar liquid can be produced by using a liquid containing the same.
[0106]
FIG. 10 is a schematic diagram showing a seventh example of the processing liquid generation device according to the present invention. Here, the silicon wafer is cleaned with the cleaning liquid generated by the apparatus shown in FIGS. 10 and 11, and the cleaning effects are compared. The device in FIG. 10 has the same basic configuration as the device shown in FIG. 5, and the device in FIG. 11 has the same basic configuration as the device shown in FIG. is there. Hereinafter, the apparatus and configuration shown in FIGS. 10 and 11 and a method for generating a cleaning liquid using the apparatus will be described.
[0107]
In the apparatus shown in FIG. 10, the inside of the container 1101 is divided into three regions by a cation exchange membrane 1111 and an anion exchange membrane 1112, and liquid is introduced by inlets 1121, 1122, 1123 and outlets 1131, 1132, 1133. The liquid can be introduced and discharged for each area. Further, each region is provided with electrodes 1141, 1142, 1143, and by flowing a current between these electrodes, it is possible to electrolyze the liquid introduced into each region.
[0108]
In this example, the inlet 1122 and the inlet 1123 of the apparatus are provided with NH as a supporting electrolyte.₄  A small amount of OH (2 × 10^-5mol / l) and an aqueous ammonium acetate solution (2 × 10^-3(mol / l), and a potential of 20 V, 10 V, or 50 V was applied to each of the electrodes 1141, 1142, and 1143 to electrolyze the aqueous solution. The solution discharged from the outlet 1132 was used for washing.
[0109]
Here, on the surface of each electrode, the following reactions mainly occur according to the respective potential differences.
Electrode 1143: 2H₂  O → 4H⁺  + O₂  + 4e⁻
Electrode 1142: 2H₂  O + 2e⁻  → H₂  + 2OH⁻
Electrode 1141: 2H₂  O → 4H⁺  + O₂  + 4e⁻
In addition, ions move as follows in the cation exchange membrane 1111 and the anion exchange membrane 1112 according to the direction of the electric field and the ion species in the liquid.
[0110]
Cation exchange membrane: NH₄  ⁺  From the electrode 1141 side to the electrode 1142 side
Anion exchange membrane: OH⁻  From the electrode 1142 side to the electrode 1143 side
Therefore, by the electrolysis reaction and ion transfer occurring between the electrode 1142 and the electrode 1143, H in the region where the electrode 1142 is installed is₂  Increase the concentration of OH⁻  The concentration hardly changes. OH on the surface of the electrode 1142⁻  Is generated, but OH⁻  Is to move via the anion exchange membrane 1112 to the region where the electrode 1143 is installed. This means the generation of a liquid with a low oxidation potential.
[0111]
In addition, due to the electrolysis reaction and ion migration generated between the electrodes 1142 and 1141, H in the region where the electrodes 1142 are installed is reduced.₂  , OH⁻  The concentration increases. This means the formation of a liquid having a high pH and a low oxidation potential.
[0112]
From the above, it can be seen that the liquid discharged from the outlet 1132 has a lower pH and lower oxidation-reduction potential than the liquid introduced from the inlet 1122. When the pH and the oxidation-reduction potential of the effluent from the outlet 1132 were measured, the pH was 8, and the oxidation-reduction potential was −0.45 V.
[0113]
In the apparatus shown in FIG. 10, the inside of the container 1201 is divided into two regions by a cation exchange membrane 1211, and liquid introduction and discharge are performed for each region by liquid introduction ports 1221 and 1222 and discharge ports 1231 and 1232. Discharge can be performed. Further, each region is provided with an electrode (electrodes 1241 and 1242), and by flowing a current between these electrodes, it is possible to electrolyze the liquid introduced into each region.
[0114]
In the apparatus shown in FIG. 11, NH is used as a supporting electrolyte at the inlet 1221.₄  A small amount of OH (2 × 10^-5mol / l), and an aqueous solution of ammonium acetate was dissolved (2 × 10^-3(mol / l), and a potential of 10 V and 20 V was applied to each of the electrodes 1241 and 1242 to electrolyze the aqueous solution. The solution discharged from the outlet 1231 was used for washing.
[0115]
Here, on the surface of each electrode, the following reactions mainly occur according to the respective potential differences.
Electrode 1241: 2H₂  O + 2e⁻  → H₂  + 2OH⁻
Electrode 1242: 2H₂  O → 4H⁺  + O₂  + 4e⁻
Since the electrode 1242 has a higher potential than the electrode 1241, the cation exchange membrane 1211 uses NH 4.⁴⁺Moves from the electrode 1242 side to the electrode 1241 side.
[0116]
Since such a reaction occurs, the liquid discharged from the outlet 1231 is more OH than the liquid introduced from the inlet 1221.⁻  , H₂  The concentration increases. When the pH and the oxidation-reduction potential of the effluent from the outlet 1232 were measured, the pH was 8, and the oxidation-reduction potential was −0.30 V.
[0117]
Next, the result of cleaning with the cleaning liquid generated by the apparatus shown in FIGS. 10 and 11 will be described.
First, in order to form an embedded wiring of Al, a groove was formed on an insulating film → Al sputtering → Al CMP. Since the polishing particles remained on the insulating film and the Al surface by the CMP, the wafer was immersed in the cleaning liquid generated by the apparatus shown in FIG. 10 or FIG. 11 and irradiated with ultrasonic waves of about 1 MHz for 10 minutes. Approximately 1 to 30,000 abrasive particles attached to the wafer surface can be cleaned by the ultrasonic treatment using the cleaning liquid generated by any one of the apparatus shown in FIG. 10 and the apparatus shown in FIG. It could be reduced below. However, when the liquid generated by the apparatus shown in FIG. 10 was used, Al was not corroded at all, whereas on the wafer using the cleaning liquid generated by the apparatus shown in FIG. 11, about 5% of Al was corroded. Was seen. This is because the former has a lower oxidation potential than the latter, so that Al oxidation and elution reaction (Al + 4OH)⁻  → Al (OH)₄  ⁻  + 3e⁻  ) Was suppressed.
[0118]
As described above, by using the present invention, a cleaning solution having a low oxidation potential was generated, and the CMP abrasive particles could be removed without corroding Al. Note that the liquid produced in the present invention, which is weakly alkaline and highly reducing, removes ionic residues such as halogen remaining on the sample surface after dry etching or the like, and reduces and removes natural oxide films such as semiconductors and metals. A good cleaning effect can be obtained even when used for a hydrogen termination treatment or the like. In the above embodiment, the inlet 1121 is provided with NH.₄  ⁺  Was used, for example, N (CH₃  )₄  ⁺  And N (CH₃  )₃  C₂  H₄  OH⁺  A similar solution can be produced by using a solution containing an alkylammonium ion.
[0119]
FIG. 12 is a schematic diagram of a cleaning liquid generation device used in the eighth example of the present invention. FIG. 11 shows a schematic view of a conventional apparatus for comparison. In a seventh example according to the present invention, a silicon wafer is cleaned with a cleaning liquid generated by the apparatus shown in FIGS. 11 and 12, and the cleaning effects are compared. The device shown in FIG. 12 has the same basic configuration as the device shown in FIG. 5 except that the potential applied to the electrodes and the solution to be introduced are only partially different. Hereinafter, the configuration of the apparatus of FIG. 12 and a method of generating a cleaning liquid using the apparatus will be described.
[0120]
In the apparatus shown in FIG. 12, the interior of the container 1301 is divided into three regions by a cation exchange membrane 1311 and an anion exchange membrane 1312, and the liquid is introduced by liquid inlets 1321, 1322, 1323 and outlets 1331, 1332, 1333. The liquid can be introduced and discharged for each area. Further, each of the regions is provided with electrodes 1341, 1342, 1343, and by flowing a current between these electrodes, the liquid introduced into each region can be electrolyzed.
[0121]
In the present embodiment, the introduction port 1322 and the introduction port 1323 of this apparatus are provided with NH.₄  OH aqueous solution (2 × 10^-5mol / l) and an aqueous solution of ammonium chloride (2 × 10^-3mol / l), and a potential of 90 V, 70 V, and 0 V was applied to each of the electrodes 1341, 1342, and 1343 to electrolyze the aqueous solution. The solution discharged from the outlet 1332 was used for washing.
[0122]
Here, on the surface of each electrode, the following reactions mainly occur according to the respective potential differences.
Electrode 1343: 2H₂  O + 2e⁻  → H₂  + 2OH⁻
The electrode 1343 side of the electrode 1342: 2OH⁻  → 2H₂  O + O₂  + 4e⁻
The electrode 1341 side of the electrode 1342: 2H₂  O + 2e⁻  → H₂  + 2OH⁻
Electrode 1341: 2H₂  O → 4H⁺  + O₂  + 4e⁻
In addition, ions move as follows in the cation exchange membrane 1311 and the anion exchange membrane 1312 according to the direction of the electric field and the ion species in the liquid.
[0123]
Cation exchange membrane: NH₄  ⁺  From the electrode 1341 side to the electrode 1342 side
Anion exchange membrane: OH⁻  From the electrode 1343 side to the electrode 1342 side
Therefore, the electrolysis reaction and the ion transfer that occur between the electrode 1342 and the electrode 1343 cause O₂  Increase the concentration of OH⁻  The concentration hardly changes (OH on the surface of the electrode 1342⁻  Disappears from the region where the electrode 1343 is installed via the anion exchange membrane 1312.⁻  Moves to compensate for the decrease). This means the generation of a liquid having a high oxidation potential. The electrolysis reaction and ion transfer generated between the other electrode 1342 and the electrode 1341 cause the H of the region where the electrode 1342 is installed to be H.₂  , OH⁻  The concentration increases. This means the formation of a liquid having a high pH and a low oxidation potential.
[0124]
As described above, the pH of the liquid discharged from the outlet 1132 is higher than that of the liquid introduced from the inlet 1322, and the change in the oxidation-reduction potential is determined by the current flowing between the electrode 1342 and the electrode 1342. It is understood that the magnitude is determined by the magnitude relationship with the current flowing between the electrodes 1343. In this example, depending on the magnitude relationship of the potential difference, more current flows in the latter, and the liquid discharged from the outlet 1332 has a higher oxidation potential than the liquid introduced from the inlet 1322. When the pH and the oxidation-reduction potential of the effluent from the outlet 1332 were measured, the pH was 9 and the oxidation-reduction potential was about 0.7 V.
[0125]
Further, in this example, the inlet 1221 of the apparatus of FIG.₄  OH aqueous solution (2 × 10^-5mol / l), and an aqueous solution of ammonium acetate was dissolved in the inlet 1222 (2 × 10^-3(mol / l), and a potential of 70 V and 90 V was applied to each of the electrodes 1241 and 1242 to electrolyze the aqueous solution. The solution discharged from the outlet 1231 was used for washing.
[0126]
Here, on the surface of each electrode, the following reactions mainly occur according to the respective potential differences.
Electrode 1241: 2H₂  O + 2e⁻  → H₂  + 2OH⁻
Electrode 1242: 2H₂  O → 4H⁺  + O₂  + 4e⁻
Since the electrode 1242 has a higher potential than the electrode 1241, the cation exchange membrane 1211 uses NH 4.₄  ⁺  Moves from the electrode 1242 side to the electrode 1241 side.
[0127]
Since such a reaction occurs, the liquid discharged from the outlet 1231 is more OH than the liquid introduced from the inlet 1221.⁻  , H₂  The concentration increases. When the pH and the oxidation-reduction potential of the discharged liquid from the outlet 1232 were measured, the pH was 9 and the oxidation-reduction potential was -0.65 V.
[0128]
Next, the result of cleaning a wafer using such a cleaning liquid will be described.
First, a contact hole was formed in an insulating film on silicon by reactive ion etching. Thereafter, in order to remove an etching residue and a damaged layer on the silicon surface on the bottom surface of the hole, the contact hole was formed by the apparatus shown in FIGS. 11 and 12. The sample was immersed in the cleaning solution and treated for 10 minutes. As a result, when cleaning was performed with the liquid generated by the apparatus shown in FIG. 12, the residue on the silicon surface was removed, and the silicon was etched by about 1 nm, thereby removing the etching damage layer. At this time, the flatness of the silicon surface hardly changed. On the other hand, when the treatment was performed using the liquid generated in the apparatus of FIG. 11, the silicon surface was etched by about 10 nm. The etched silicon had a surface roughness of several nm.
[0129]
This is because the liquid at the bottom of the contact hole is OH⁻  This is because the ions have been etched. The surface roughness is due to the fact that this etching has a plane orientation dependence of silicon (for example, the etching rate of the (111) plane <the etching rate of the (100) plane). On the other hand, when the treatment is performed with the cleaning solution generated by the apparatus shown in FIG. 13, the silicon surface on the bottom of the hole is first covered with a natural oxide film because the solution has a high oxidizing property.⁻  Etched by Therefore, the etching amount of silicon is small and the surface is not roughened much.
[0130]
As described above, by using the present invention, a liquid suitable for cleaning the contact hole could be generated. Such a weak alkali and highly oxidizable liquid is also effective for removing particles on the surface of a silicon oxide film, removing contaminated metals, and the like. HCl and NH₄  Cl or the like is mixed into the liquid introduced from the inlets 1322 and 1323 or the liquid discharged from the outlet 1332, and Cl is added to the liquid.⁻  When treated with a liquid having introduced thereinto, the efficiency of removing metal contamination such as Fe was improved. This is the Cl in the liquid⁻  However, it has the effect of forming and stabilizing dissolved metal ions and complex ions. Cl⁻  Besides, Br⁻  , I⁻  , SO_x  ^2-, NO_x  ⁻  The same effect was obtained by incorporating a chelating agent or the like into the cleaning solution. In the above embodiment, the inlet 1321 is provided with NH.₄  ⁺  Was used, for example, N (CH₃  )₄  ⁺  And N (CH₃  )₃  C₂  H₄  OH⁺  A similar solution can be produced by using a solution containing an alkylammonium ion.
[0131]
The present invention is not limited to the above-described example. For example, the solution produced by the present invention may be mixed with another cleaning solution such as hydrofluoric acid for use, or used for purposes other than cleaning, for example, a thin film of polysilicon or the like. It can also be used as a polishing liquid for removal or CMP. In the above-described embodiment, one electrode is provided in a region sandwiched between the cation exchange membrane and the anion exchange membrane, and electrolysis is performed between the electrode and the electrodes in the other two regions. Two electrodes may be provided in a region between the cation exchange membrane and the anion exchange membrane, and electrolysis may be performed between each of the two electrodes and the other two electrodes. In addition, the present invention can be variously modified and implemented without departing from the spirit thereof.
[0132]
【The invention's effect】
According to the processing liquid generator of the present invention, the pH and the oxidation-reduction potential of the anode water and the cathode water can be controlled independently. Therefore, for example, it is possible to obtain cathode water having a high oxidation potential and anode water having a high reduction potential.
[0133]
Further, according to the method for manufacturing a semiconductor device of the present invention, a solution having a pH and an oxidation-reduction potential according to the type of the contaminated metal can be freely obtained. It is possible to perform cleaning without contaminating the anode, and further, it is possible to suppress corrosion of the anode and suppress adsorption of metal ions to the cathode.
[Brief description of the drawings]
FIG. 1 is a diagram showing a range of pH and oxidation-reduction potential of treated water.
FIG. 2 is a schematic diagram showing a first example of a processing liquid generation device according to the present invention.
FIG. 3 is a schematic view showing a second example of the processing liquid generating apparatus according to the present invention.
FIG. 4 is a schematic view showing a third example of the processing liquid generating apparatus according to the present invention.
FIG. 5 is a schematic diagram illustrating a fifth example of the processing liquid generation device according to the present invention.
FIG. 6 is a schematic diagram of a conventional cleaning liquid generation device.
FIG. 7 is a pH-redox potential equilibrium diagram of Cu
FIG. 8 is a schematic diagram showing a sixth example of the processing liquid generation device according to the present invention.
FIG. 9 is a pH-redox potential equilibrium diagram of Ti.
FIG. 10 is a schematic diagram illustrating a seventh example of the processing liquid generation device according to the present invention.
FIG. 11 is a schematic diagram of a conventional cleaning liquid generation device.
FIG. 12 is a schematic view showing an eighth example of the processing liquid generation device according to the present invention.
FIG. 13 is a phase diagram of Fe with respect to pH and redox potential E.
FIG. 14 is a phase diagram of Cr with respect to pH and redox potential E.
[Explanation of symbols]
11, 21, 31 ... container
12, 22, 32 ... anode
13, 23, 33 ... cathode
14, 24, 34a, 34b ... diaphragm
611,911,1111,1211,1311 ... cation exchange membrane
612, 712, 912, 1112, 1312 ... anion exchange membrane
641, 642, 643, 941, 942, 943, 1141, 1142, 1143, 1241, 1242, 1341, 1342, 1343 ... electrodes

Claims (10)

An anode and a cathode are immersed in a solution with a diaphragm interposed therebetween, and a reducing gas supply for supplying a reducing gas to the solution near the anode and an oxidizing gas supply for supplying an oxidizing gas to the solution near the cathode At least with performing hand gas supply step performs current between anode and cathode, wherein a performing process step using the obtained treatment liquid by electrolyzing the solution of Manufacturing method. A container body for holding the solution, a partition for dividing the container body into two regions, an anode and a cathode each immersed in the solution in the two regions, and a reducing gas supplied near the anode that it comprises at least one gas supply means of the oxidizing gas supply means, and means for performing current between the anode and the cathode to supply the reducing gas supply means and the cathode near the oxidizing gas to An apparatus for generating a processing liquid, comprising: An anode and a cathode are immersed and disposed in a solution with a diaphragm interposed therebetween, and at least one of an oxidizing gas and a reducing gas is supplied to a solution near one of the anode and the cathode, and the anode and the cathode are arranged. A method for manufacturing a semiconductor device using a processing solution obtained by electrolyzing the solution by conducting electricity during the process, wherein at least one of the anode and the cathode selects a gas with respect to the solution. A method for manufacturing a semiconductor device, comprising: a gas permeable member that transmits light. A container body that holds the solution, a partition that divides the container body into two regions, an anode and a cathode that are respectively immersed in the solution in the two regions, and a vicinity of one of the anode and the cathode A processing solution comprising: a gas supply means for supplying one of a reducing gas and an oxidizing gas; or an exhaust means for exhausting a gas in the solution; and a means for conducting electricity between the anode and the cathode. a production apparatus, at least one electrode of the anode and the cathode, generating device of the treatment liquid, characterized by comprising a gas-permeable member for selectively transmitting the gas to the solution. A first and a second region separated by a first partition at least partly composed of a cation exchange membrane and a second partition at least partly composed of an anion exchange membrane, and between the first and second partitions; The first, second, and third electrodes are respectively immersed in the first, second, and third solutions contained in the respective regions of the container divided into the third region located at Applying a different potential to each of the three electrodes to electrolyze the solution, and then performing a processing step using a processing solution obtained from the third region. . A container body for holding the solution, and the inside of the container body is divided into a first area, a second area, and a third area located between the first and second areas. A first diaphragm comprising at least a portion comprising a cation exchange membrane disposed between the first and third regions, and at least a portion disposed between the second and third regions. Are respectively immersed and arranged in the first, second, and third solutions contained in the first, second, and third regions, respectively. An apparatus for generating a processing liquid, comprising: first, second, and third electrodes; and means for applying different potentials to the first, second, and third electrodes, respectively. A first partition having a cation exchange membrane and a second partition having an anion exchange membrane are separated by a first partition, a second partition, and a third partition located between the first partition and the second partition. First, second, and third electrodes are respectively immersed and arranged in first, second, and third solutions respectively contained in the respective regions of the divided container, and the three electrodes are different from each other. A method for manufacturing a semiconductor device, comprising applying a potential, electrolyzing the solution, and then performing a processing step using a processing solution obtained from the third region.
  When the potential applied to the first electrode is A, the potential applied to the second electrode is B, and the potential applied to the third electrode is C, the first solution is ammonium ion And a cation containing one of alkylammonium ions, wherein A> C> B. A first partition having a cation exchange membrane and a second partition having an anion exchange membrane are separated by a first partition, a second partition, and a third partition located between the first partition and the second partition. First, second, and third electrodes are respectively immersed and arranged in first, second, and third solutions contained in respective regions of the divided container, and the three electrodes are different from each other. After applying an electric potential to electrolyze the solution, the solution is obtained from the third region. A method for manufacturing a semiconductor device performing a processing step using the processing liquid obtained,
  When the potential applied to the first electrode is A, the potential applied to the second electrode is B, and the potential applied to the third electrode is C, the first solution is ammonium ion And A> C and B> C, the method comprising manufacturing one of the following. A first partition having a cation exchange membrane and a second partition having an anion exchange membrane are separated by a first partition, a second partition, and a third partition located between the first partition and the second partition. First, second, and third electrodes are respectively immersed and arranged in first, second, and third solutions respectively contained in the respective regions of the divided container, and the three electrodes are different from each other. A method for manufacturing a semiconductor device, comprising applying a potential, electrolyzing the solution, and then performing a processing step using a processing solution obtained from the third region,
  When the potential applied to the first electrode is A, the potential applied to the second electrode is B, and the potential applied to the third electrode is C, the second solution may be halogen. An ion, a hydrogen halide ion, a halogen oxide ion, a sulfate ion, a nitrate ion, a carbonate ion, a phosphate ion, and at least one anion selected from the group consisting of hydrogen peroxide ions, wherein A <C < B. A method for manufacturing a semiconductor device, comprising: A first partition having a cation exchange membrane and a second partition having an anion exchange membrane are separated by a first partition, a second partition, and a third partition located between the first partition and the second partition. First, second, and third electrodes are respectively immersed and arranged in first, second, and third solutions contained in respective regions of the divided container, and the three electrodes are different from each other. A method for manufacturing a semiconductor device, comprising applying a potential, electrolyzing the solution, and then performing a processing step using a processing solution obtained from the third region,
  When the potential applied to the first electrode is A, the potential applied to the second electrode is B, and the potential applied to the third electrode is C, the second solution is a halogen ion And at least one anion selected from the group consisting of hydrogen halide ions, halogen oxide ions, sulfate ions, nitrate ions, carbonate ions, phosphate ions, and hydrogen peroxide ions, wherein A <C and B <C. A method for manufacturing a semiconductor device, wherein

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