1291200 f (1) 玖、發明說明 相關申請案 此申請案主張2002年1月7日提出申請的 U.S.Provisional Application 第 60/346,507 5虎之權利。將則 述申請案所述者全數列入參考° 【發明所屬之技術領域及先前技術】 對於污染物敏感的物件之製造通常須使用一或多種溶 液以自物件移除雜質。傳統上，那些溶劑以液相使用。最 近，使用越來越常以超臨界二氧化碳代替液態溶劑。使用 超臨界二氧化碳通常會減少水的消耗量，減少廢液，減少 散逸和/或增進溶解性。半導體製造中’超臨界二氧化碳 用於許多應用，如：光阻物顯影、光阻物剝除、晶圓淸潔 和晶圓乾燥。 通常，超臨界流體是局於其臨界壓力和溫度的流體’ 其並且具有類似氣體和液體的性質。超臨界流體（如：超 臨界二氧化碳）的溶劑性質視流體密度而定，後者又視流 體的壓力/溫度條件而定。用於許多有機雜質時，二氧化 碳的溶劑化性質隨著流體壓力自超臨界降至較低壓力 (如：大氣壓）而降低，此發生於淸潔操作所用腔的減壓期 間內。用於高純度淸潔操作’如：晶圓製造或製造或加工 處理其他工件或底質期間內所見者，隨著壓力的下降，雜 質沉澱於二氧化碳溶劑中，其會損及欲淸理的表面，污染 此表面並降低淸潔程序的效能。 -5- 1291200 t \ (2) 因此，對於減少或儘量減少前述問題地潔淨物件 (如：晶圓或其他工件）的方法有需求存在。 【發明內容】 本發明一般係關於淸潔物件的方法，使物件與包括二 氧化碳的溶劑流體接觸，藉此自物件移除雜質，及以置換 用的流體置換溶劑流體。此置換用的流體不是二氧化碳。 〜個實施例中，物件是晶圓，置換係於足以防止在溶劑流 體中形成第二相的溫度和壓力下進行。另一實施例中，置 換係於足以防止在欲置換的溶劑流體中形成的第二相的溫 度和壓力下進行，且二氧化碳再循環至流體中。 另一實施例中，本發明針對減少非揮發性渣質於工件 淸潔操作期間內沉澱的方法。此方法的步驟包括：工件與 溶劑流體於第一個壓力接觸，溶劑流體包括二氧化碳，藉 此，工件上的污染物被溶劑流體所移除；降低溶劑流體壓 力，使得非揮發性渣質不溶解於溶劑流體中；及於低壓以 二氧化碳以外的置換用氣體置換溶劑流體，藉此減少工件 暴於不溶性非揮發性渣質中的時間，藉此減少不溶性非揮 發性渣質澱積於工件上的情況。 另一實施例中，本發明針對將淸潔用流體施用於容器 中的方法。此方法的步驟包括：於第一個壓力，將溶劑流 體流供應至放置物件的容器，其中，溶劑流體包括二氧化 碳，能夠溶解容器中物件上的污染物；將置換用流體流供 應至容器，其中，置換用流體流的壓力足以置換容器中的 -6- 1291200 (3) 溶劑流體’置換用流體不是二氧化碳；及將溶劑流體排至 容器外。 本發明有數個優點。例如，實施本發明之方法得到超 乾淨表面’如半導體製造和其他工業所須者。本發明之方 法經濟且容易與已有的製造設備成一體。例如，一個特點 中’本發明之方法使用氮置換用氣體，設備通常有氮管 線。一個實施例中，可以使用可資利用的低壓（如：8 〇 _ lOOpsig)氮。另一實施例中，使用過的二氧化碳係經循 環’以減少二氧化碳消耗及相關成本。另一實施例中，再 循環可以在不須壓縮使用過的流體的條件下進行。此外， 本發明將可能存在於更高純度等級二氧化碳中的非揮發性 殘留雜質以及它們於容器減壓時的沉澱作用造成的問題列 入考慮。 【實施方式】 由下列關於本發明之較佳實施例的更特別描述和附 圖’會更瞭解本發明前述和其他目的、特徵和優點，附圖 中’類似編號是與相同組件。附圖未依標準規格，以強調 方式說明本發明之原理。 本發明一般係關於製造潔淨表面，此如半導體製造或 加工期間內所須者。本發明係關於移除、防止或儘量減少 污染物沉積於晶圓（如：包括一或多種電機械裝置的晶 圓）、一或多種積體電路或其組合上，此爲此技術中已知 者。可以使用本發明加工的其他工件包括半導體製造中所 1291200 (4) # 用的零件（如：噴雜祀和其他者）、光學零件（如：光學鏡 片、頻率倍增裝置、發出雷射光的晶體、分光組件、光 腔、纖維鏡）和其他者。物件（如：電視、攝影機和照相機 零件、科學和藥學儀器、衛星傳輸、航空工業中所用零件 及其他）及其他工件亦可以此處所述者處理。 物件可製自任何材料，包括無機物（如：砂、二氧化 砂、石墨或金屬）、有機物（如··聚合物）或製自無機和有機 材料之組合的物質。淸潔法可用於單一物件，或者可用以 同時淸潔二或多個物件。 本發明係關於自物件或環繞物件的環境（如：物件製 造或加工期間內，放置物件的容器）移除污染物或雜質的 方法。此方法本身可以是較大的製造操作，如：沉積或生 長膜的方法，光蝕刻法、蝕刻法、離子植入法、化學機械 平面化法、擴散法、光阻顯影法、使光敏材料顯影的方 法、淸潔光學組件的方法、淸潔可用於航空應用之組件的 方法、光阻物剝除法、晶圓淸潔法、晶圓乾燥法、去脂法 或萃取法。 污染物包括最終產物不欲含有的有機和/或無機材 料。匕們可能是固體、液體或氣體形式。例子包括聚合 物、脂和其他有機材料、矽、碳、和/或金屬及其他雜 質。它們可存在於物件表面上或擴散於包含此物件之材料 的至少一部分。 雜質可由物件本身產生，並可包括在晶圓加工期間內 移除的晶圓部分或蝕刻程序期間內製得的碎物。雜質亦可 -8 - 1291200 (5) ， 能隨處理流體送至物件。操作完成之後，化學品（如：製 造或處理物件所用者）也可能留在物件表面上，或可能存 在於加工容器中。 本發明特別適用以移除非揮發性殘渣（NVR)。操作期 間內’使用高壓二氧化碳，特別是於或接近臨界或超臨界 條件，許多N V R溶解於二氧化碳中。隨著壓力的降低， 二氧化碳的密度和溶劑性質改變，N V R沉源形成第二相， 通常爲氣溶膠液滴和/或固體細粒形式。在第二相中， NVR會衝擊物件表面，因此造成污染。 非揮發性殘渣的例子包括，如：烴（如：C^ + )、重質 烴和其他者，但不在此限。 N V R來源包括壓縮機油、漆、可溶於溶劑中並常見於 襯墊中的彈性材料和閥密封材料、溶劑進料管中所用密封 劑及其他。可能於加工操作期間內（如：晶圓淸潔期間內） 於工件上形成NVR。 亦可使用物件製造、加工或淸潔期間內所用的流體， 使NVR與物件表面接觸。 ' 半導體工業中’例如’光阻物顯影、光阻物剝除、晶 圓淸潔和晶圓乾燥期間內’使用二氧化碳。咸信整個二氧 化碳流體含有的NVR濃度不超過i0ppm(以重量計）。一些 較咼純度等級（鋼瓶中者）含有約0 . 1 5 p p m N V R (以重量計）。 用於敏感程序中時’其要求最終物件僅能含有低於特 定數目的選定尺寸顆粒，即使更高等級也帶有無法接受量 的NVR。例如，一些製法中，要求每標準立方米氣體所含 1291200 , (6) 高於某些規定尺寸（基本上約1 〇〇奈米）的顆粒數目低於 100個。估計一升較高純度等級液態二氧化碳（約10ppb)的 汽化反應會得到百萬個NV R顆粒。爲達到這樣的淸潔程 度，必須至少將目前供應的最高純度二氧化碳的純度提高 1 000 倍。 使用高壓二氧化碳的淸潔期間內’第二相NVR之形 成示於附圖1 A、1 B和1 C。附圖1A所示者是放置晶圓1 2 的腔10。腔10是容器或器皿，如：在半導體製造設備中 的工具或加工區。腔1 〇設計用以接收和留置高壓流體’ 如：超臨界二氧化碳（高於其臨界溫度和壓力的二氧化 碳，特定言之，高於31 °C和1070磅/平方英吋（Psia))。 腔10備有通道（用以引入加工流體和其他化學品）及抽氣 通道，此如此技術已知者。引入和抽空腔1 〇的方式爲此 技術所習知。例子包括壓縮機、幫浦、抽氣閥和其他。 如附圖1A所示者，腔10充滿二氧化碳至壓力爲 2 000磅/平方英吋（psig)。於此壓力，晶圓上的污染物溶 解於二氧化碳溶劑中，第二相（不溶的）NVR濃度極低。隨 著腔10減壓至較低壓力（如：200psig)(如附圖2B所示 者），之後至常壓（如附圖1 C所示者），二氧化碳的溶劑化 性質朝向NVR消失及第二相形成。腔10中的第二相NVR 會衝擊晶圓而造成污染。 一個實施例中，本發明之方法包括使物件（如：晶圓） 與包括二氧化碳的溶劑流體接觸，使得物件上的污染物溶 解於溶劑流體中。以純度較高的二氧化碳爲佳。其他實施 •10- 1291200 % ⑺ 例中，本發明之方法可以使用整體二氧化碳。 通常，溶劑流體包括至少50重量％二氧化碳。溶劑 流體中的二氧化碳含量以至少7 5重量％爲佳，至少90重 量％較佳，至少9 8重量％最佳。 此溶劑流體可以是100%二氧化碳。其他實施例中， 溶劑流體包括至少一種額外組份，如··輔助溶劑、界面活 性劑或鉗合劑。除了二氧化碳以外，可用組份的（單獨或 倂用）例子包括氨水、鹵化烴、氫氟酸、二氧化硫和其他 者。輔助溶劑、界面活性劑和/或鉗合劑的其他例子包括 矽烷；烴，如：甲烷、乙烷、丙烷、丁烷、己烷、乙烯和 丙烯；鹵化烴，如：四氟甲烷、氯二氟甲烷、六氟化硫和 全氟丙烷；無機物，如：氨、氦、氪、氬和氧化亞氮； 醇’如：乙醇、甲醇或異丙醇；碳酸丙二酯；大氣氣體， 如：氮、氫、臭氧或氧；水；胺，如：羥基胺和烷醇胺； 丙酮；吡咯啉酮，如：N -甲基吡咯啉酮、N -乙基吡咯啉 酮、N-羥基乙基吡咯啉酮和N-環己基吡咯啉酮；醯胺， 包括二甲基乙醯胺或二甲基甲醯胺；酚和其衍生物；乙二 醇醚；2-吡咯啉酮；二烷基礪；有機和無機酸及它們衍生 物，如：氫氟酸、氫氯酸、乙酸、硫酸、五倍子酸或五倍 子酸酯；四烷基氫氧化銨；二氟化銨；銨-四甲基二氟化 銨；鹼金屬氫氧化物；酒石酸鹽；磷酸鹽；乙二胺四醋酸 鹽（EDTA);銨與硫化鈉和硫酸鐵；及它們的混合物。 通常，包括二氧化碳的溶劑流體處於污染物（如： N V R)可溶解於溶劑流體中的條件下。例如，包括二氧化 1291200 % (8) 碳的溶劑流體壓力至少800psig。較佳情況中，包括二氧 化碳的溶劑流體處於或接近其臨界狀態或處於超臨界條 件。 二氧化碳溶劑可以蒸汽、液體或超臨界相引至容器 中。一旦進入容器內，二氧化碳溶劑與物件接觸，以移除 雜質。雜質之移除可藉物理或化學機構完成，例如，二氧 化碳溶劑可溶解雜質；雜質可自製造物件的材料擴散進入 二氧化碳溶劑；或者，溶劑與二氧化碳溶劑反應，使得它 們自物件移出。此移除亦可爲機械機構，例如，可調整二 氧化碳溶劑的壓力和/或溫度，以提高和/或降低其比體 積，構成壓力使得雜質自物件中被逼出。亦可藉化學和機 械機構之組合移除雜質。 視情況地，可以攪動此二氧化碳溶劑，以增進化學和 機械機構。例如，攪動能夠因爲提高物件表面濃度梯度， 而提高化學移除機構（如：溶解、擴散反應）的速率，藉此 使化學機構趨於完全。類似地，攪動也會提高機械移除機 構的移除速率，這是因爲攪動在流體中形成剪力，此有助 於自物件表面拉出雜質之故。 可以調整二氧化碳的溫度和/或壓力以有助於移除雜 質。這些處理條件之調整會使的二氧化碳溶劑驅動蒸汽、 液體和/或超臨界相之間的一或多相轉變，此視對於二氧 化碳溶劑選用的調整與臨界溫度和/或壓力及其冷凝壓力 和/溫度而定。這些調整以有助於雜質移除爲佳。若物件 上或物件中有數種不同類型的雜質，二氧化碳溶劑可以循 -12- 1291200 Ο) · 環於各種處理條件之間，以增進各種類型的雜質之移除。 二氧化碳溶劑施以這些調整時，N V R或移除的雜質可能溶 入和/或沉澱於溶劑流體中。 視情況地，至少一部分包括污染物的溶劑流體可於居 間淸潔步驟以新進流體或純二氧化碳代替，藉此，使用過 的溶劑流體被推移流動’可自欲淸潔的表面移除額外污染 物。 此方法包括以置換用流體（非二氧化碳）於足以避免在 欲加以置換的溶劑流體中形成第二相的溫度和壓力條件下 置換溶劑流體，藉此，自晶圓分離污染物，藉此淸潔晶 圓。 例如，溶劑流體於容器中的壓力條件下被置換，未經 部分或總容器降壓處理。如果容器經降壓，可以降至NVR 於溶劑流體中的溶解度得以維持的壓力。 置換用的流體可以是氣體、液體或超臨界流體。適當 之置換用的流體是氮、氨、氬或氪、其他氣體（如：氧）和 它們的任何組合。以氮爲佳。本發明的一個實施例中，置 換用的流體是高純度氣體。另一實施例中，置換用的流體 是超高純度氣體，如：純度程度使得所有污染物量爲次 ppb者或工業已知者。高純度和超高純度氣體（如：氮和其 他者）可購自市面上。 本發明之方法可以連續或批次方式進行。 本發明的此實施例階段之說明示於附圖2A_ 2D。 附圖2 A所示者是放置晶圓1 2的腔1 4。腔1 4可以是 -13- 1291200 猶 (10) 如前述的容器。其他實施例中’腔1 4可經設計，使得新 進流體進入容器中’與已存在的二氧化碳溶劑混合（例 如，以連續攪拌容器反應器模式）或者使得流動路徑有助 於使用過的溶劑、雜質和N v R之置換（如：以塞流模式）。 較佳情況中’容器形狀儘可能在二氧化碳溶劑、雜質和 NVR的置換期間內，減少物件中的雜質和NVR。如此技 術已知者，可配備用以將引入流體和抽空腔1 4中之流體 的通道和裝置。 如附圖 2A所示者，腔 14塡滿二氧化碳至約 200Opsig，其中包括溶解的污染物。 如附圖2B所示者，壓力高於容器中之二氧化碳的惰 性氣體（如：高於2000psig)引至腔14中。如附圖2C所示 者，二氧化碳和溶解的污染物自腔1 4中被置換出來。如 附圖2D所示者，包括置換用氣體的腔14之後減壓至大氣 壓。 使用較高純度的置換用流體和/或二氧化碳溶劑，或 者提高所用置換用流體的體積，以更徹底置換二氧化碳溶 劑、雜質和NVR，抽真空之後，留在物件上的最終雜質數 目獲改善。 一旦溶劑流體、NVR和其他雜質自容器置換出來，可 以中止置換用流體流，可以將容器抽空。 自容器置換出的二氧化碳可視爲廢流或可引至設備中 的其他操作或工具。 一個較佳實施例中，自腔1 4置換出的流體經純化， -14- 1291200 « (11) 例如，將容器排出的流體引至一或多個純化單元。因腔 14排出流體壓力高（如，20OOpsig)，所以，使用過的流體 通常引至純化單元中，不須進一步壓縮。可利用的純化技 巧例包括蒸餾、吸附、吸收、化學反應、相分離和其他方 法。 經置換的溶劑流體可針對NVR、輔助溶劑、界面活性 劑和鉗合劑純化。其他實施例中，所得流體可經進一步純 化以自置換用流體（如：氮）分離二氧化碳。適用以自氮分 離二氧化碳的方法包括蒸餾。 一個較佳實施例中，二氧化碳經再循環’此如2002 年8月17日提出申請的美國專利申請案第10/274,302 號，Recycle for Supercritical Carbon Dioxide (超臨界一氧 化碳之再循環）中所述之再循環，茲將其中所述者全數列 入參考。 置換用流體亦可再循環。如果使用氦作爲置換用流 體，因其成本和其顯著的質輕特性使得移除較易，所以再 循環特別有吸引力。 另一實施例中，本發明係關於降低非揮發性渣質於工 件淸潔操作期間內澱積的方法。此方法包括使工件與溶劑 流體（基本上是前述者）接觸。此方法包括降低溶劑流體壓 力，藉此，污染物（如：NVR)可溶於溶劑流體中。此方法 另包括於減低壓力下，以置換用流體（如前述者）置換溶劑 流體，藉此，工件暴於不溶性污染物（如：NVR)的期間降 低，藉此減少不溶性污染物（如：NVR)於工件上之沉積。 1291200 (12) 一個實施例中，溶劑流體的壓力降至低於約 lOOOpsig。另一實施例中，壓力降至低於200paig。另一實 施例中，溶劑流體壓力降至比氮氣來源或設備管線壓力低 的値，如：降至低於約8(M00psig。 較佳情況中，晶圓暴於不溶性NVR的時間低於30秒 鐘。晶圓暴於不溶性NVR的時間低於3秒鐘更佳。 視情況地，至少一部分溶劑流體和溶解的污染物可於 居間的淸洗步驟以使用新進溶劑流體或純二氧化碳置換。 此淸洗步驟可於容器減壓之前或之後進行。二氧化碳和選 用的置換氣體可再循環，此如前述者。再循環可包括將欲 循環的流體引至純化器之前的壓縮步驟。 如前述者，此方法可以連續或批次方式進行。 本發明的此實施例階段的一個例子示於附圖3A-3E。 附圖3A中所示者是放置晶圓12的腔14，此基本上如前 述者。壓力約2000psig的二氧化碳存在於腔14中。腔14 降壓至200psig，此如附圖3B所示者。壓力下降之後， NVR自溶液沉澱出來，形成第二相。惰性氣體（如：氮）的 壓力足以推動200psiag溶劑流體進入腔14，此如附圖3C 所示者，藉此置換腔14中的二氧化碳和第二相雜質，此 如附圖3D所示者。置換容器中的二氧化碳和第二相雜質 可縮短晶圓暴於不溶性NVR中的時間，藉此減少不溶性 NVR於晶圓上之沉積。如附圖3E所示者，腔14之後降壓 至常壓。 一個實施例中，本發明係關於製造超乾淨物件的方 -16- 1291200 (13) 法。此處所謂的"超乾淨"是指底質的污染程度低於約 2,000個顆粒/平方米表面積，此雜質的有效直徑大於約 0.1微米，此藉光散射技巧測得。此技術已經知道測定固 體表面上之有效直徑大於約0.1微米顆粒的光散射法。例 如，適當方法述於R.P. Donovan編輯的 Contamination-Free Manufacturing for Semiconductors and other Precision Products(半導體和其他精準產物之無污染產製）（Mar cell Dekker，2001 年）中第 79 頁的 Diaz, R.E.，等人，’’〇11-Wafer Measurement of Particles in Contamination- Free Manufacturing for Semiconductors and other Precision Products (半導體和其他精準產物之無污染產製中的晶圓 上顆粒測定）"。 此方法包括使物件於容器中與二氧化碳溶劑接觸，藉 此，物件上的雜質溶解於二氧化碳溶劑中，及將置換用氣 體引至容器中，以縮短物件暴於存在於二氧化碳中之非揮 發性雜質的時間，藉此將物件上的雜質數目降至低於約 2000個顆粒/平方米表面積，其中，由光散射技術測得 雜質的有效直徑大於0.1微米。 另一實施例中，本發明提出一種將淸潔用流體供應至 容器的方法。此方法的步驟包括將於第一個壓力的溶劑流 體流供應至放置物件的容器，其中，溶劑流體包括二氧化 碳且能夠將物件上的污染物溶解於容器中；將置換用流體 流供應至容器，其中，置換用流體流的壓力足以置換容器 中的溶劑流，且置換用流體不是二氧化碳；及將溶劑流體 -17- 1291200 (14) 排出容器外。 自容器排出的流體可經純化（如前述者），二氧化碳可 循環至容器中。經純化的二氧化碳回到容器之前，可經此 技術已知方式壓縮。 一個實施例中，置換用流體流壓力至少與第一個壓力 等壓。一個實例中，置換用流體壓力比其置換的溶劑流體 壓力高不超過約100p si。另一實施例中，第一個壓力是至 少lOOOpsig。自容器排出的流體壓力可以比純化單元的操 作壓力來得高。 另一實施例中，溶劑流體自容器排出的壓力比第一個 壓力來得低，置換用流體的壓力足以推動溶劑流體。 已經參考較佳實施例地特別提出和描述本發明，嫻於 此技術者瞭解如何由所描述的細節在不違背所附申請專利 範圍涵蓋之本發明範圍的情況下作出各式各樣改變。 【圖式簡單說明】 附圖1 A -1 C所示者是放置與二氧化碳接觸的物件的容 器中壓力下降時，第二相的形成階段。 附圖2A_ 2D是本發明的一個實施例的方法步驟。 附圖3A-3E是本發明另一實施例的方法步驟。 主要元件對照表 1〇 腔 12 晶圓 -18- 1291200 (15) 14 腔1291200 f (1) 玖, Invention Description Related Applications This application claims the rights of U.S. Provisional Application 60/346, 507 5, which was filed on January 7, 2002. All of the persons referred to in the application are listed as references. [Technical Fields and Prior Art to Which the Invention pertains] The manufacture of articles sensitive to contaminants typically requires the use of one or more solutions to remove impurities from the articles. Traditionally, those solvents have been used in the liquid phase. Recently, it has become more and more common to replace liquid solvents with supercritical carbon dioxide. The use of supercritical carbon dioxide generally reduces water consumption, reduces waste, reduces dissipating and/or enhances solubility. In semiconductor manufacturing, 'supercritical carbon dioxide' is used in many applications such as photoresist development, photoresist stripping, wafer cleaning, and wafer drying. Generally, supercritical fluids are fluids that are at their critical pressure and temperature and have similar gas and liquid properties. The solvent properties of supercritical fluids (e.g., supercritical carbon dioxide) depend on the fluid density, which in turn depends on the pressure/temperature conditions of the fluid. When used in many organic impurities, the solvating properties of carbon dioxide decrease as the fluid pressure drops from supercritical to lower pressure (e.g., atmospheric pressure), which occurs during the decompression of the chamber used for the cleaning operation. For high-purity cleaning operations such as: wafer fabrication or manufacturing or processing of other workpieces or substrates during the period, as the pressure drops, impurities precipitate in the carbon dioxide solvent, which will damage the surface to be treated , contaminate this surface and reduce the effectiveness of the cleaning process. -5- 1291200 t \ (2) Therefore, there is a need for a method for reducing or minimizing the aforementioned problems of clean objects (such as wafers or other workpieces). SUMMARY OF THE INVENTION The present invention is generally directed to a method of cleaning articles that contact an object with a solvent fluid comprising carbon dioxide, thereby removing impurities from the article and displace the solvent fluid with a replacement fluid. The fluid used for this replacement is not carbon dioxide. In one embodiment, the article is a wafer and the displacement is performed at a temperature and pressure sufficient to prevent formation of the second phase in the solvent stream. In another embodiment, the replacement is performed at a temperature and pressure sufficient to prevent the second phase formed in the solvent fluid to be displaced, and the carbon dioxide is recycled to the fluid. In another embodiment, the present invention is directed to a method of reducing non-volatile slag deposits during a workpiece cleaning operation. The method comprises the steps of: contacting the workpiece with the solvent fluid at a first pressure, the solvent fluid comprising carbon dioxide, whereby the contaminants on the workpiece are removed by the solvent fluid; reducing the pressure of the solvent fluid, so that the non-volatile slag is insoluble Dissolving the solvent fluid in a solvent fluid; and replacing the solvent fluid with a replacement gas other than carbon dioxide at a low pressure, thereby reducing the time during which the workpiece is exposed to the insoluble non-volatile slag, thereby reducing the deposition of the insoluble non-volatile slag on the workpiece. Happening. In another embodiment, the invention is directed to a method of applying a fluid for cleaning to a container. The method includes the steps of: supplying a solvent fluid stream to a container in which the article is placed, wherein the solvent fluid comprises carbon dioxide, capable of dissolving contaminants on the article in the container; and supplying the fluid stream for replacement to the container, wherein The pressure of the fluid stream for displacement is sufficient to replace the -6-1291200 in the vessel. (3) Solvent Fluid The fluid for replacement is not carbon dioxide; and the solvent fluid is discharged outside the vessel. The invention has several advantages. For example, the method of practicing the invention results in an ultra-clean surface' as required by semiconductor manufacturing and other industries. The method of the present invention is economical and easy to integrate with existing manufacturing equipment. For example, in one feature, the method of the present invention uses a gas for nitrogen replacement, and the apparatus usually has a nitrogen line. In one embodiment, a useful low pressure (e.g., 8 〇 _ lOO psig) of nitrogen can be used. In another embodiment, the used carbon dioxide is recycled to reduce carbon dioxide consumption and associated costs. In another embodiment, the recirculation can be carried out without compressing the used fluid. In addition, the present invention contemplates the problems associated with non-volatile residual impurities that may be present in higher purity grades of carbon dioxide and their precipitation upon depressurization of the vessel. The above and other objects, features and advantages of the present invention will become more apparent from the <RTIgt; The drawings illustrate the principles of the invention in an emphasized manner. The present invention is generally directed to the manufacture of clean surfaces, such as those required during semiconductor fabrication or processing. The present invention relates to removing, preventing or minimizing the deposition of contaminants on a wafer (eg, a wafer including one or more electromechanical devices), one or more integrated circuits, or a combination thereof, as is known in the art. By. Other workpieces that can be processed using the present invention include parts used in semiconductor manufacturing 1291200 (4) # (eg, squirrels and others), optical components (eg, optical lenses, frequency multipliers, crystals that emit laser light, Spectroscopic components, optical cavities, fiberscopes, and others. Objects (such as televisions, camera and camera parts, scientific and pharmaceutical instruments, satellite transmissions, parts used in the aerospace industry, and others) and other workpieces can also be handled as described herein. The article may be made of any material, including inorganic materials (e.g., sand, silica, graphite or metal), organic materials (e.g., polymers), or materials derived from a combination of inorganic and organic materials. The chast method can be used for a single item, or it can be used to clean two or more items at the same time. The present invention relates to a method of removing contaminants or impurities from the environment of an article or surrounding article (e.g., a container in which the article is placed during manufacture or processing of the article). The method itself may be a large manufacturing operation, such as a method of depositing or growing a film, a photolithography method, an etching method, an ion implantation method, a chemical mechanical planarization method, a diffusion method, a photoresist development method, and developing a photosensitive material. Methods, methods for purifying optical components, methods for cleaning components for aerospace applications, photoresist stripping, wafer cleaning, wafer drying, degreasing or extraction. Contaminants include organic and/or inorganic materials that the final product does not intend to contain. They may be in solid, liquid or gaseous form. Examples include polymers, fats and other organic materials, germanium, carbon, and/or metals and other impurities. They may be present on the surface of the article or diffuse at least a portion of the material comprising the article. Impurities may be generated by the article itself and may include portions of the wafer that are removed during wafer processing or debris produced during the etching process. Impurities can also be -8 - 1291200 (5), can be sent to the object with the treatment fluid. After the operation is complete, chemicals (such as those used to make or handle the item) may also remain on the surface of the item or may be present in the processing container. The invention is particularly useful for removing non-volatile residues (NVR). During the operation, high pressure carbon dioxide is used, especially at or near critical or supercritical conditions, and many N V R are dissolved in carbon dioxide. As the pressure decreases, the density of the carbon dioxide and the nature of the solvent change, and the N V R sink source forms a second phase, typically in the form of aerosol droplets and/or solid fine particles. In the second phase, the NVR can impact the surface of the object, thus causing contamination. Examples of non-volatile residues include, for example, hydrocarbons (e.g., C^+), heavy hydrocarbons, and others, but are not limited thereto. Sources of N V R include compressor oils, lacquers, elastomeric materials and valve sealing materials that are soluble in solvents and are commonly used in gaskets, sealants used in solvent feed tubes, and others. It is possible to form an NVR on the workpiece during the processing operation (eg, during the wafer cleaning period). The NVR can also be brought into contact with the surface of the object by using the fluid used during the manufacture, processing or cleaning of the article. In the semiconductor industry, for example, in the development of photoresist, photoresist stripping, wafer cleaning, and wafer drying, carbon dioxide is used. The entire carbon dioxide fluid contains a concentration of NVR of no more than i0 ppm by weight. Some of the helium purity grades (in the cylinder) contain about 0.15 p p m N V R (by weight). When used in sensitive procedures, it requires that the final object can only contain particles of a selected size below a certain number, even at higher levels with an unacceptable amount of NVR. For example, in some processes, the number of particles per standard cubic meter of gas is 129,1200, and (6) is higher than some specified sizes (essentially about 1 nanometer). It is estimated that one liter of vaporization reaction of higher purity grade liquid carbon dioxide (about 10 ppb) will yield millions of NV R particles. In order to achieve such a degree of cleanliness, at least the purity of the highest purity carbon dioxide currently supplied must be increased by a factor of 1,000. The formation of the second phase NVR during the cleaning period using high pressure carbon dioxide is shown in Figures 1 A, 1 B and 1 C. The one shown in Figure 1A is the cavity 10 in which the wafer 1 2 is placed. The chamber 10 is a container or vessel, such as a tool or processing zone in a semiconductor manufacturing facility. The chamber 1 is designed to receive and retain high pressure fluids such as: supercritical carbon dioxide (carbon dioxide above its critical temperature and pressure, specifically above 31 ° C and 1070 pounds per square inch (Psia)). The chamber 10 is provided with passages (to introduce process fluids and other chemicals) and suction passages, as is known in the art. The manner in which the cavity is introduced and evacuated is known to the art. Examples include compressors, pumps, exhaust valves, and others. As shown in Figure 1A, chamber 10 is filled with carbon dioxide to a pressure of 2 000 pounds per square inch (psig). At this pressure, the contaminants on the wafer dissolve in the carbon dioxide solvent and the second phase (insoluble) NVR concentration is extremely low. As chamber 10 is depressurized to a lower pressure (eg, 200 psig) (as shown in Figure 2B), then to atmospheric pressure (as shown in Figure 1 C), the solvation properties of carbon dioxide disappear toward the NVR and Two phases are formed. The second phase NVR in cavity 10 can impact the wafer and cause contamination. In one embodiment, the method of the present invention includes contacting an article (e.g., a wafer) with a solvent fluid comprising carbon dioxide such that contaminants on the article dissolve in the solvent fluid. It is preferred to use carbon dioxide of higher purity. Other implementations • 10-1291200% (7) In the example, the method of the present invention can use monolithic carbon dioxide. Typically, the solvent fluid comprises at least 50% by weight carbon dioxide. The carbon dioxide content of the solvent fluid is preferably at least 75 wt%, preferably at least 90 wt%, and most preferably at least 98 wt%. This solvent fluid can be 100% carbon dioxide. In other embodiments, the solvent fluid comprises at least one additional component, such as an auxiliary solvent, an interfacial surfactant, or a chelating agent. In addition to carbon dioxide, examples of the components that can be used (alone or in combination) include ammonia, halogenated hydrocarbons, hydrofluoric acid, sulfur dioxide, and others. Other examples of auxiliary solvents, surfactants and/or chelating agents include decane; hydrocarbons such as methane, ethane, propane, butane, hexane, ethylene and propylene; halogenated hydrocarbons such as tetrafluoromethane, chlorodifluorocarbon Methane, sulfur hexafluoride and perfluoropropane; inorganic substances such as ammonia, hydrazine, hydrazine, argon and nitrous oxide; alcohols such as: ethanol, methanol or isopropanol; propylene carbonate; atmospheric gases such as nitrogen , hydrogen, ozone or oxygen; water; amines, such as: hydroxylamines and alkanolamines; acetone; pyrrolidone, such as: N-methylpyrrolidone, N-ethylpyrrolidone, N-hydroxyethylpyrrole Linoleone and N-cyclohexylpyrrolidinone; decylamine, including dimethylacetamide or dimethylformamide; phenol and its derivatives; glycol ether; 2-pyrrolidone; Organic and inorganic acids and their derivatives, such as: hydrofluoric acid, hydrochloric acid, acetic acid, sulfuric acid, gallic acid or gallic acid ester; tetraalkylammonium hydroxide; ammonium difluoride; ammonium-tetramethyldifluoro Ammonium; alkali metal hydroxide; tartrate; phosphate; ethylenediaminetetraacetate (EDTA); ammonium with sodium sulfide and sulfur Iron; and mixtures thereof. Typically, a solvent fluid comprising carbon dioxide is in a condition where a contaminant (e.g., N V R) is soluble in the solvent fluid. For example, a solvent fluid pressure comprising 1291200% (8) carbon dioxide is at least 800 psig. Preferably, the solvent fluid comprising carbon dioxide is at or near its critical state or is in a supercritical condition. The carbon dioxide solvent can be introduced into the vessel in a vapor, liquid or supercritical phase. Once inside the container, the carbon dioxide solvent contacts the object to remove impurities. Removal of impurities can be accomplished by physical or chemical means, for example, a carbon dioxide solvent can dissolve impurities; impurities can diffuse from the material of the article of manufacture into the carbon dioxide solvent; or the solvent reacts with the carbon dioxide solvent to cause them to move out of the article. This removal may also be a mechanical mechanism, for example, the pressure and/or temperature of the carbon dioxide solvent may be adjusted to increase and/or decrease its specific volume, constituting a pressure such that impurities are forced out of the article. Impurities can also be removed by a combination of chemical and mechanical mechanisms. Optionally, this carbon dioxide solvent can be agitated to enhance chemical and mechanical mechanisms. For example, agitation can increase the rate of chemical removal mechanisms (e.g., dissolution, diffusion reactions) by increasing the surface concentration gradient of the article, thereby tending to complete the chemical mechanism. Similarly, agitation also increases the rate of removal of the mechanical removal mechanism because agitation creates shear forces in the fluid which aid in the extraction of impurities from the surface of the article. The temperature and/or pressure of the carbon dioxide can be adjusted to help remove impurities. These processing conditions are adjusted to cause the carbon dioxide solvent to drive one or more phase transitions between the vapor, liquid, and/or supercritical phase, depending on the adjustment of the carbon dioxide solvent selection and the critical temperature and/or pressure and its condensing pressure and/or Depending on the temperature. These adjustments are preferred to aid in the removal of impurities. If there are several different types of impurities on or in the object, the carbon dioxide solvent can be circulated between various treatment conditions to enhance the removal of various types of impurities. When these adjustments are applied to the carbon dioxide solvent, N V R or the removed impurities may be dissolved and/or precipitated in the solvent fluid. Optionally, at least a portion of the solvent fluid comprising the contaminant may be replaced with a fresh fluid or pure carbon dioxide in the intermediate cleaning step, whereby the used solvent fluid is displaced by the flow of 'additional contaminants from the surface to be cleaned . The method includes displace the solvent fluid with a displacement fluid (non-carbon dioxide) under conditions of temperature and pressure sufficient to avoid formation of a second phase in the solvent fluid to be replaced, thereby separating the contaminants from the wafer, thereby cleaning Wafer. For example, the solvent fluid is replaced under pressure conditions in the vessel and is not subjected to a partial or total vessel depressurization treatment. If the vessel is depressurized, it can be reduced to a pressure at which the solubility of the NVR in the solvent fluid is maintained. The fluid for displacement can be a gas, a liquid or a supercritical fluid. Suitable replacement fluids are nitrogen, ammonia, argon or helium, other gases such as oxygen, and any combination thereof. Nitrogen is preferred. In one embodiment of the invention, the fluid for replacement is a high purity gas. In another embodiment, the fluid for displacement is an ultra-high purity gas such as a purity level such that the amount of all contaminants is sub-ppb or known to the industry. High purity and ultra high purity gases such as nitrogen and others are commercially available. The process of the invention can be carried out in a continuous or batch manner. A description of the stages of this embodiment of the invention is shown in Figures 2A-2D. The one shown in Figure 2A is the cavity 14 in which the wafer 12 is placed. The chamber 14 can be -13-1291200 (10) as described above. In other embodiments, 'cavity 14 can be designed such that fresh fluid enters the vessel' mix with existing carbon dioxide solvent (eg, in a continuously stirred vessel reactor mode) or allows the flow path to aid in the use of solvents, impurities Replacement with N v R (eg, in plug flow mode). Preferably, the container shape reduces impurities and NVR in the article as much as possible during the replacement of carbon dioxide solvent, impurities and NVR. Channels and devices for introducing fluid and evacuating fluid in the cavity 14 can be provided as is known in the art. As shown in Figure 2A, the chamber 14 is full of carbon dioxide to about 200 Opsig, including dissolved contaminants. As shown in Figure 2B, an inert gas having a higher pressure than the carbon dioxide in the vessel (e.g., above 2000 psig) is introduced into the chamber 14. As shown in Figure 2C, carbon dioxide and dissolved contaminants are displaced from the chamber 14. As shown in Fig. 2D, the chamber 14 including the replacement gas is then depressurized to atmospheric pressure. The higher purity displacement fluid and/or carbon dioxide solvent is used, or the volume of the replacement fluid used is increased to more completely displace the carbon dioxide solvent, impurities and NVR, and the number of final impurities remaining on the article is improved after evacuation. Once the solvent fluid, NVR, and other impurities are displaced from the vessel, the fluid stream for displacement can be discontinued and the vessel can be evacuated. The carbon dioxide displaced from the vessel can be considered a waste stream or other operation or tool that can be introduced into the equipment. In a preferred embodiment, the fluid displaced from the chamber 14 is purified, -14-1291200 « (11) For example, the fluid discharged from the vessel is directed to one or more purification units. Since the fluid pressure of the chamber 14 is high (e.g., 20 00 psig), the used fluid is usually introduced into the purification unit without further compression. Examples of purification techniques that may be utilized include distillation, adsorption, absorption, chemical reactions, phase separation, and other methods. The displaced solvent fluid can be purified for NVR, auxiliary solvents, surfactants, and chelating agents. In other embodiments, the resulting fluid may be further purified to separate carbon dioxide from a displacement fluid (e.g., nitrogen). Suitable methods for separating carbon dioxide from nitrogen include distillation. In a preferred embodiment, the carbon dioxide is recycled as described in U.S. Patent Application Serial No. 10/274,302, the entire disclosure of which is incorporated herein by reference. Recycling, all of which are included in the reference. The replacement fluid can also be recycled. If helium is used as the fluid for replacement, the recycling is particularly attractive because of its cost and its remarkable light weight characteristics. In another embodiment, the present invention is directed to a method of reducing non-volatile slag deposition during a workpiece cleaning operation. This method involves contacting the workpiece with a solvent fluid (essentially the foregoing). This method involves reducing the pressure of the solvent fluid whereby contaminants (e.g., NVR) are soluble in the solvent fluid. The method further includes replacing the solvent fluid with a displacement fluid (such as the foregoing) under reduced pressure, whereby the workpiece is exposed to insoluble contaminants (e.g., NVR), thereby reducing insoluble contaminants (e.g., NVR). ) deposition on the workpiece. 1291200 (12) In one embodiment, the pressure of the solvent fluid is reduced to less than about 1000 psig. In another embodiment, the pressure drops below 200 paig. In another embodiment, the solvent fluid pressure is reduced to a lower pressure than the nitrogen source or equipment line pressure, such as to fall below about 8 (M00 psig. Preferably, the wafer is exposed to the insoluble NVR for less than 30 seconds. Preferably, the wafer is exposed to the insoluble NVR for less than 3 seconds. Optionally, at least a portion of the solvent fluid and dissolved contaminants may be replaced by a new solvent fluid or pure carbon dioxide in an intermediate scrubbing step. The washing step can be carried out before or after the vessel is decompressed. The carbon dioxide and the optional replacement gas can be recycled, as described above. The recycling can include a compression step prior to introducing the fluid to be circulated to the purifier. The method can be carried out in a continuous or batch manner. An example of this embodiment of the invention is illustrated in Figures 3A-3E. The one shown in Figure 3A is the cavity 14 in which the wafer 12 is placed, substantially as hereinbefore described. Carbon dioxide at a pressure of about 2000 psig is present in chamber 14. Chamber 14 is depressurized to 200 psig as shown in Figure 3B. After the pressure drops, NVR precipitates out of solution to form a second phase. The pressure of nitrogen) is sufficient to push the 200 psiag solvent fluid into the chamber 14, as shown in Figure 3C, thereby displacing the carbon dioxide and second phase impurities in the chamber 14, as shown in Figure 3D. And the second phase impurity can reduce the time that the wafer is exposed to the insoluble NVR, thereby reducing the deposition of the insoluble NVR on the wafer. As shown in Figure 3E, the cavity 14 is then depressurized to atmospheric pressure. In one embodiment The present invention relates to the method of making ultra-clean articles, the method of "16-1291200 (13). The so-called "ultra-clean" means that the degree of contamination of the substrate is less than about 2,000 particles per square meter of surface area, this impurity The effective diameter is greater than about 0.1 microns, as measured by light scattering techniques. This technique has known light scattering methods for determining particles having an effective diameter greater than about 0.1 micron on a solid surface. For example, a suitable method is described in RP Donovan, Contamination-Free Manufacturing for Semiconductors and other Precision Products (Marcell Dekker, 2001), Diaz, RE, et al., page 79 '〇11-Wafer Measurement of Particles (particles measured on a wafer made of semiconductor and other pollution-free production of precision in product) in Contamination- Free Manufacturing for Semiconductors and other Precision Products ". The method comprises contacting an object with a carbon dioxide solvent in a container, whereby impurities on the object are dissolved in a carbon dioxide solvent, and the replacement gas is introduced into the container to shorten the object to be exposed to non-volatile impurities present in the carbon dioxide. The time thereby reducing the number of impurities on the article to less than about 2000 particles per square meter of surface area, wherein the effective diameter of the impurities is greater than 0.1 micrometer as measured by light scattering techniques. In another embodiment, the invention provides a method of supplying a cleaning fluid to a container. The method includes the step of supplying a first pressurized solvent fluid stream to a container in which the article is placed, wherein the solvent fluid comprises carbon dioxide and is capable of dissolving contaminants on the article in the container; the displacement fluid stream is supplied to the container, Wherein the pressure of the fluid stream for displacement is sufficient to displace the solvent stream in the vessel, and the fluid for displacement is not carbon dioxide; and the solvent fluid -17-1291200 (14) is discharged outside the vessel. The fluid discharged from the vessel can be purified (as described above) and carbon dioxide can be recycled to the vessel. The purified carbon dioxide can be compressed in a manner known per se prior to returning to the vessel. In one embodiment, the fluid flow for displacement is at least equal to the pressure of the first pressure. In one example, the fluid pressure for displacement is no more than about 100 psi higher than the pressure of the solvent fluid it is replacing. In another embodiment, the first pressure is at least 1000 psig. The fluid pressure discharged from the vessel can be higher than the operating pressure of the purification unit. In another embodiment, the pressure of the solvent fluid from the container is lower than the first pressure, and the pressure of the replacement fluid is sufficient to push the solvent fluid. The present invention has been particularly described and described with reference to the preferred embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 A - 1 C shows the formation phase of the second phase when the pressure in the container in which the article in contact with carbon dioxide is lowered. 2A-2D are method steps of one embodiment of the present invention. 3A-3E are method steps of another embodiment of the present invention. Main components comparison table 1 腔 cavity 12 wafer -18- 1291200 (15) 14 cavity
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