JP3789297B2 - Polishing fluid supply device - Google Patents
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- JP3789297B2 JP3789297B2 JP2000351097A JP2000351097A JP3789297B2 JP 3789297 B2 JP3789297 B2 JP 3789297B2 JP 2000351097 A JP2000351097 A JP 2000351097A JP 2000351097 A JP2000351097 A JP 2000351097A JP 3789297 B2 JP3789297 B2 JP 3789297B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、研磨液の供給装置に関するものであり、詳しくは、例えば、半導体ウエハの研磨加工に使用される化学機械研磨用の研磨液を研磨装置へ供給する研磨液の供給装置であって、研磨液における所定粒径以上の粒径の砥粒の発生をインラインで連続的に管理できる研磨液の供給装置に関するものである。
【０００２】
【従来の技術】
半導体デバイスは、一層の高集積化、高速化および低消費電力化が要求されており、その製造プロセスにおいては、ウエハ上に形成されるメタル配線や層間絶縁膜の表面をより平坦化するため、例えば、シリカ系の研磨液（ＣＭＰスラリー）を使用し、研磨装置によってウエハの表面に化学機械研磨を施している。そして、研磨加工に使用される研磨液は、正確なポリッシングレートを得るため、厳密に砥粒濃度を管理される必要がある。また、研磨液においては、漸次、砥粒の凝集が進行し、凝集した大粒の砥粒がウエハに対するスクラッチの発生の一因となる虞があるため、研磨液中の砥粒の大きさの管理がより重要になっている。
【０００３】
研磨装置へ供給される研磨液の管理においては、研磨液をサンプリングして純水で希釈した後、一定波長の光を照射し、その透過光や散乱光の強度を測定することにより、研磨液中の粒径の大きな砥粒の数を測定している。サンプリングによって研磨液を管理する理由は次の通りである。すなわち、研磨液中の砥粒を製造ライン上で直接測定しようとすると、ポンプの脈動などによる流量変動が影響するため、正確に砥粒の数を計測できない。また、上記の様なシリカ系研磨液は、例えば、平均粒径で０．２μｍ程度のシリカ砥粒が１０13個／ｍｌと非常に高濃度であり且つ問題となる粒径の大きな砥粒の数が少ない。従って、仮に、粒径が３μｍ以上に凝集した砥粒を検出する場合でも、適正な粒径の砥粒による光の減衰により、直接測定によっては大粒径の砥粒による減衰を検出し難い。
【０００４】
【発明が解決しようとする課題】
ところで、上記の様な研磨液中の大粒径の砥粒の検出には、比較的長い時間を要するため、実際、サンプリングされた研磨液に対し、使用される研磨液に差異が生じる。すなわち、使用される研磨液は、サンプリング時よりも更に凝集が進行するために大粒径の砥粒をより多く含んでおり、その結果、研磨加工においては、予想外に、ウエハにスクラッチが発生することがある。
【０００５】
本発明は、上記の実情に鑑みてなされたものであり、その目的は、半導体デバイス製造プロセスの研磨加工に使用される化学機械研磨用の研磨液などを供給する研磨液の供給装置であって、研磨液における所定粒径以上の粒径の砥粒の発生をインラインで連続的に且つ一層高精度に管理できる研磨液の供給装置を提供することにある。
【０００６】
【課題を解決するための手段】
上記の課題を解決するため、本発明に係る研磨液の供給装置は、主に純水および砥粒から成る研磨液を研磨装置へ供給する研磨液の供給装置であって、研磨液の供給源から研磨装置に至る管路および流量調整可能なそのバイパス管路を備え、かつ、前記バイパス管路には、所定粒径以上の粒径の砥粒を検出し且つその数を計測する研磨液監視用のパーティクル検出器が設けられ、当該パーティクル検出器は、研磨液が通過するフローセルに一定波長の光を照射し、前記所定粒径以上の粒径の砥粒による透過光の減衰を検出する光遮断方式の検出器であり、前記フローセルは、前記バイパス管路の流量調整によって一定の流速で研磨液が通過可能に構成されていることを特徴とする。
【０００７】
すなわち、上記の供給装置においては、研磨液供給用の管路によって供給源の研磨液を研磨装置へ供給し、また、バイパス管路に設けられた研磨液監視用のパーティクル検出器は、研磨液が通過するフローセルに一定波長の光を照射し、所定粒径以上の粒径の砥粒による透過光の減衰を検出する。その際、流量調整可能なバイパス管路にパーティクル検出器が設けられた構造、および、バイパス管路の流量調整によって一定の流速で研磨液が通過可能なフローセルの構造は、フローセルにおける研磨液の流量が制限されると共に、研磨液供給用の管路に生じた脈動などによる影響がなく、しかも、フローセルに流れる研磨液中の所定粒径未満の砥粒の絶対数が低減されるため、所定粒径未満の粒径の砥粒による透過光の減衰と、所定粒径以上の粒径の砥粒による透過光の減衰とを分離できる。
【０００８】
また、上記の供給装置において、パーティクル検出器には、所定粒径以上の粒径の砥粒による透過光の減衰を検出する際、研磨液中の所定粒径未満の砥粒による感度低下を補正する校正機能が備えられているのが好ましく、斯かる校正機能は、所定粒径以上の粒径の砥粒による透過光の減衰に対する検出感度を高めることが出来る。
【０００９】
【発明の実施の形態】
本発明に係る研磨液の供給装置の一実施形態を図面に基づいて説明する。図１は、本発明に係る研磨液の供給装置の概要ならびに研磨液の供給源の一例としての研磨液の調製装置を示す系統図である。図２は、本発明に係る研磨液の供給装置に適用されるパーティクル検出器の原理を一部破断して示す図であり、分図（ａ）は側面図、分図（ｂ）は平面図である。また、図３は、パーティクル検出器のセンサーからの出力および変換された制御用のパルス信号の例を示すグラフである。なお、図１の系統図においては、弁類や計装機器などを省略している。また、以下の実施形態の説明においては、適宜、研磨液の供給装置を単に「供給装置」と略記する。
【００１０】
本発明の供給装置は、図１に符号（Ｌ５）で示す様に、主に純水および砥粒から成る研磨液、典型的には、例えば、半導体デバイスの研磨に適用される化学機械研磨用のシリカ系研磨液（ＣＭＰスラリー）を研磨装置（９）へ供給する供給装置であり、研磨液中の所定粒径以上の粒径の砥粒（以下、適宜「大粒径の砥粒」と言う。）の数をインラインで高精度に管理し得る装置である。
【００１１】
シリカ系研磨液の場合、その主成分は、ヒュームドシリカの砥粒と純水であり、砥粒の粒径は、通常は５μｍ未満、好ましくは３μｍ未満、より好ましくは０．１〜２μｍであり、また、砥粒の含有量は、一般的には１０〜３０重量％である。また、上記の研磨液には、必要に応じて添加剤が添加されてもよい。添加剤としては、メタル配線の表面を研磨する場合やプラグを除去する場合、これらを酸化し得る成分であればよく、一般的には過酸化水素が使用される。また、シリコン層を研磨する場合は、水酸化カリウム等のアルカリが添加剤として使用される。これらの酸またはアルカリは、後述する添加剤供給装置（Ｌ３）を通じて水溶液として添加される。
【００１２】
研磨装置（９）は、キャリアプレートによって被研磨面が下面に露出する状態にウエハを加圧保持し且つ定盤上で移動させることにより、ウエハ表面に連続的に研磨処理を施すいわゆる公知の定盤装置であり、一般的な研磨装置の構造は、例えば、特開平２−４１８６９号公報に記載されている。
【００１３】
具体的には、研磨装置は、上面に研磨クロスが装着され且つ一方向に回転するテーブル状の定盤と、被研磨面が下面に露出する状態に複数枚のウエハを同一平面レベルで保持する複数組のキャリアプレートと、定盤の中心に設けられ且つ当該定盤と伴回りするセンターローラーと、定盤外周側の一定位置に周方向に沿って等間隔で吊持された回転自在な複数組のガイドローラーと、定盤の上方から支持され且つ定盤上に配置された各キャリアプレートを定盤に向けて一定の力で加圧する複数組の加圧盤（ウエイト）とから構成される。
【００１４】
上記の研磨装置においては、センターローラーと各ガイドローラーとの距離がキャリアプレートの直径よりも小さく設定されており、ウエハを保持した各キャリアプレートは、回転する定盤上に配置された場合、ウエイトによって加圧され、かつ、センターローラーとガイドローラーによって一定の位置に保持されると共に、センターローラーを介して定盤の回転力が伝達されることにより、キャリアプレート自体も回転する様になされている。すなわち、研磨装置においては、定盤を回転させることにより、ウエハの表面に対し、相対的に研磨クロスを複雑に回転運動させ、そして、研磨液を供給しつつ、研磨処理を施す。
【００１５】
本発明の供給装置（Ｌ５）は、図１に示す様に、通常、各研磨装置（９）へ研磨液を供給するための複数の供給ラインによって構成されており、各供給ラインは、研磨液の供給源（Ｓ１）から研磨装置（９）に至る研磨液供給用の管路（５７）及び流量調整弁（図示省略）やオリフィス等によって流量調整可能なそのバイパス管路（５７１）を備えている。そして、バイパス管路（５７１）には、研磨装置（９）へ供給する研磨液における大粒径の砥粒の発生を管理するためのパーティクル検出器（８）が設けられる。
【００１６】
研磨液の供給源としては、予め一定の砥粒濃度に調製された研磨液、または、一定の砥粒濃度に調製され且つ添加剤が添加された研磨液を貯留する可搬式または固定式の貯槽を利用することも出来るが、一般的には、図１に示す様なオンサイトで研磨液を調製する研磨液調製装置（Ｓ１）が利用される。
【００１７】
先ず、研磨液調製装置（Ｓ１）について説明すると、研磨液調製装置（Ｓ１）は、概略、原液槽（１）を含む原液供給装置（Ｌ１）、調製槽（２）、研磨液槽（３）ならびに研磨液循環装置（Ｌ４）等から構成される。原液供給装置（Ｌ１）は、原液槽（１）から調製槽（２）にスラリー原液（高濃度の研磨液）を圧送する装置であり、原液槽（１）から調製槽（２）へ至る配管（５１）、ベローズ方式などの定流量ポンプ（図示省略）等から構成されている。原液槽（１）は、スラリー原液を調製槽（２）に供給するための貯槽であり、耐腐食性を備えた固定式容器または可搬式容器によって構成される。
【００１８】
調製槽（２）は、研磨液の濃度を所定濃度に調整し且つ濃度調整された研磨液を貯留するための貯槽であり、例えば、耐腐食性を高めるため、フッ素樹脂でライニングした容器によって構成される。調製槽（２）には、受け入れるスラリー原液や純水の重量を計量するための計量器、液量を計測するための光式、導電率式、静電容量式などのポイント測定可能な液面計（図示省略）が設けられる。そして、調製槽（２）は、原液供給装置（Ｌ１）によって一定濃度のスラリー原液が供給され、純水供給装置（Ｌ２）（図示省略）によって純水が供給される様になされている。
【００１９】
純水供給装置（Ｌ２）は、調製槽（２）に希釈用の純水を供給する装置であり、イオン交換樹脂などによって超純水を分離精製する公知の純水供給装置から調製槽（２）に至る管路（５２）を備えている。純水供給装置（Ｌ２）は、通常、純水供給装置に付設されたポンプを利用し、純水供給装置で製造された純水を調製槽（２）へ圧送する様になされている。
【００２０】
研磨液調製装置（Ｓ１）においては、調製槽（２）で混合調製された研磨液をポンプ（４１）及び管路（５３）によって研磨液槽（３）へ移送する様になされている。なお、図中の管路（５３）には、必要に応じて研磨液の濃度をモニターし且つ調製槽（２）へ研磨液を戻すための返流用の管路が分岐して設けられてもよい。
【００２１】
研磨液槽（３）は、調製された研磨液を研磨装置（９）へ供給するためのバッファタンクであり、上記の様な酸またはアルカリの添加剤が供給されるため、例えば、フッ素樹脂でライニングされた耐腐食性の容器によって構成される。研磨液槽（４）には、研磨液の液量や添加剤の添加量を計測するため、光式、導電率式、静電容量式などのポイント測定可能な液面計（図示省略）が設けられる。そして、研磨液槽（３）は、添加剤供給装置（Ｌ３）によって上記の様な添加剤が供給される様になされている。
【００２２】
研磨液槽（３）に添加剤を供給するための添加剤供給装置（Ｌ３）は、別途設けられた添加剤槽（図示省略）から研磨液槽（３）に添加剤を圧送する装置であり、添加剤槽から添加剤を取り出すための管路（図示省略）、流量が可変で且つ一定流量に制御可能なマグネットポンプ等の送液用の定量ポンプ（図示省略）、および、研磨液槽（３）へ添加剤を供給する管路（５５）等から成る。
【００２３】
更に、研磨液槽（３）においては、砥粒成分の沈降や凝集を防止するため、研磨液を常時撹拌する撹拌機構が設けられてもよい。撹拌機構は、撹拌羽根などの回転装置、あるいは、研磨液循環装置（Ｌ４）の管路（５６）の返流側の先端に付設されたジ噴流発生用のジェットノズル（図示せず）によって構成される。なお、図示しないが、上記の研磨液調製装置（Ｓ１）においては、研磨液と添加剤の混合効率を高めるため、調製槽（２）と研磨液槽（３）の間に混合槽を配置し、調製槽（２）から供給される研磨液と添加剤供給装置（Ｌ３）から供給される添加剤とを混合槽において予め混合した後、添加剤の添加された研磨液を研磨液槽（３）で貯留する様になされていてもよい。
【００２４】
研磨液循環装置（Ｌ４）は、研磨液槽（３）で貯留される研磨液における砥粒の均一な懸濁状態を維持し、かつ、必要に応じて供給装置（Ｌ５）の各管路（５７）（供給ライン）へ直ちに研磨液を供給するための装置であり、研磨液槽（３）の研磨液を循環可能に構成されている。具体的には、研磨液循環装置（Ｌ４）は、研磨液槽（３）から研磨液を取り出し且つ研磨液槽（３）へ研磨液を戻すための研磨液循環用の管路（５６）、および、研磨液を送るポンプ（４２）、大きな粒径の砥粒を濾過するフィルタ（６１）から主として構成される。なお、図１中の各貯槽内は、空気との接触を防止するため、窒素などの不活性ガスを充填可能になされている。
【００２５】
上記の研磨液調製装置（Ｓ１）における研磨液の調製方法は次の通りである。すなわち、最初に原液槽（１）から調製槽（２）へ一定砥粒濃度のスラリー原液を計量供給し、純水供給装置（Ｌ２）によって調製槽（２）へ純水を所定量計量供給した後、調製槽（２）において研磨液を混合調製する。その際、スラリー原液あるいは純水の供給量を微調整することにより、研磨液の砥粒濃度（スラリー濃度）を例えば１５重量％に調整する。そして、調製槽（２）にて調製された研磨液を研磨液槽（３）へ管路（５３）を通じて供給する。
【００２６】
次いで、研磨液槽（３）へ供給された研磨液に対し、添加剤供給装置（Ｌ３）から管路（５５）を通じ、前述の様な添加剤を必要に応じて供給する。そして、研磨液槽（３）に設けられた上記の撹拌機構によって添加剤を撹拌混合し、所定の砥粒濃度で且つ所定の添加剤濃度の研磨液を調製する。なお、添加剤の濃度は、研磨液循環装置（Ｌ４）の管路（５６）中の研磨液の一部を濃度測定装置に供給し、その測定結果に基づいて添加剤供給装置（Ｌ３）からの添加剤の供給量または管路（５３）から供給される研磨液の供給量を制御することによって調整する。
【００２７】
研磨液槽（３）にて最終的に調製された所定の組成の研磨液は、研磨液循環装置（Ｌ４）によって循環させる。すなわち、ポンプ（４２）及び管路（５６）を使用し、研磨液槽（３）から取り出した研磨液を再び研磨液槽（３）へ返流させることにより、研磨液における砥粒の均一な懸濁状態を維持する。また、その際、管路（５６）に介装されたフィルタ（６１）により、循環する研磨液において凝集の進行した大粒径の砥粒を捕捉する。これにより、大粒径の砥粒を略含まない研磨液を管路（５６）に循環させることが出来る。そして、管路（５６）の研磨液は、供給装置（Ｌ５）によって研磨装置（９）へ供給される。
【００２８】
ところで、上記の様に調製された研磨液は、前述の様に、粒径が例えば３μｍ未満の砥粒を分散させた液体であるが、時間の経過に伴って砥粒の凝集が進行する。そこで、本発明の供給装置（Ｌ５）においては、研磨装置（９）へ供給する研磨液をインラインで管理し、大粒径の砥粒によるウエハのスクラッチを防止するため、各管路（５７）のバイパス管路（５７１）には、所定粒径以上の粒径の砥粒、例えば３μｍ以上の粒径の砥粒を検出し且つその数を計測する研磨液監視用のパーティクル検出器（８）が設けられる。
【００２９】
前述した通り、シリカ系研磨液における適性な砥粒の平均的粒径を例えば３μｍ未満とした場合、凝集の進行により粒径が３μｍ以上、場合によっては数μｍ以上になることがあるが、斯かる大粒径の砥粒の数は、研磨液中の適正な粒径の砥粒の数に比べて極めて少数である。例えば、シリカ系研磨液において適正な砥粒の平均粒径を０．２μｍ程度とした場合、その数が１０13個／ｍｌであるのに対し、スクラッチの原因となる大粒径の砥粒の数は１０〜１０００個／ｍｌ程度である。そこで、パーティクル検出器（８）としては、研磨液が通過するフローセル（８４）に一定波長の光を照射し、所定粒径以上の粒径の砥粒による透過光の減衰を検出する光遮断方式の検出器が使用される。
【００３０】
光遮断方式の検出器の基本的な構造は公知であり、斯かる検出器は、透明なフローセルを流れる流体（スラリー）に光を照射し、受光素子によって透過光の光量を検出する構造を備え、フローセル中を通過した粒子による光の吸収、反射または散乱による光量の減少によって粒子の大きさを計測し、また、パルスとして得られる光量の変化の回数によって粒子の数を計測する様になされている。
【００３１】
具体的には、図２に示す様に、パーティクル検出器（８）の主要部は、電源回路（８１）によって供給される電力により一定波長の光を発光するタングステンランプ、発光ダイオード、半導体レーザー等の光源（８２）、光源（８２）から照射された光を例えば扁平な帯状の光束に集光する集光レンズ（８３）、石英ガラス等の透明性材料によって例えば方形状断面の筒状に形成されたフローセル（８４）、フローセル（８４）を通過した光源（８２）の透過光の強度を検出するフォトダイオード、光アレイ等の受光素子（８５）、および、受光素子（８５）の出力信号を増幅する増幅器（８６）、および、当該受光素子の信号を演算処理する演算処理手段（記憶・演算素子を含む演算回路）等から成る。
【００３２】
一般的に、研磨液中の大粒径の砥粒の計測においては、前述の通り、砥粒濃度が例えば１０〜３０重量％の研磨液中の極めて少数の砥粒を検出しなければならない。従って、検出対象の大粒径の砥粒の粒径の下限値の設定によっては、適正な砥粒による光の吸収、反射または散乱による影響（ノイズ）が大きく、大粒径の砥粒を正確に検出し難い。更に、ポンプ等の機器によって流体に脈動あある場合には、粒子数を正確に計測できない。
【００３３】
これに対し、本発明においては、流量が制限されたバイパス管路（５７１）にパーティクル検出器（８）を設けることにより、研磨液供給用の管路（５７）における脈動の影響を防止し、かつ、適正な粒径の砥粒による影響（ノイズ）を低減し、数の少ない大粒径の砥粒の正確な検出を可能にしている。すなわち、フローセル（８４）は、バイパス管路（５７１）の流量調整によって一定の流速で研磨液が通過可能に構成される。通常、フローセル（８４）における研磨液の流量は１〜５００ｍｌ／分に設定され、流速は０．１〜１ｍ／秒に設定される。また、一層正確に大粒径の砥粒を検出するため、フローセル（８４）における光の透過距離は、好ましくは０．１〜１００ｍｍに設定される。
【００３４】
更に、本発明の製造装置においては、循環する研磨液中の大粒径の砥粒を一層高精度に検出するため、パーティクル検出器（８）には、予め設定された所定粒径以上の粒径の砥粒による透過光の減衰を検出する際、研磨液中の所定粒径未満の砥粒（適正な粒径の砥粒）による感度低下を補正する校正機能が備えられている。斯かる校正機能は、通常、上記の演算処理手段に設けられる。
【００３５】
すなわち、図３（ａ）に示す様に、パーティクル検出器（８）において、受光素子（８５）は、受光した光の信号をパルス信号として出力するが、上記の演算処理手段は、得られたパルス信号を図３（ｂ）に示す様な波形に波形処理した後、標準試料によって予め設定された下限の閾値電圧よりも高い信号を計数する様になされている。上記の標準試料としては、所定粒径未満の砥粒（例えば粒径が３μｍ未満の砥粒）を一定量（例えば１５重量％）含み且つ検出すべき粒径（例えば３μｍ）と同一の粒径のポリスチレンラテックス粒子を標準粒子として加えられた研磨液が使用される。
【００３６】
更に、本発明の供給装置（Ｌ５）においては、研磨装置（９）へより高品位の研磨液を供給し得る様に、管路（５７）には、予め設定された所定粒径以上の粒径の砥粒、例えば粒径が３μｍ以上の砥粒を捕捉するフィルタ（６２）がパーティクル検出器（８）の上流側に配置される。斯かるフィルタ（６２）としては、孔径が１．０〜５．０μｍ程度に設計されたポリプロピレン製のデプスタイプの濾材を備えた通常の流体用フィルタが使用される。
【００３７】
図１中に例示した制御装置（１０）は、供給装置（Ｌ５）の弁類の開閉などを制御する制御装置であり、機器の信号をデジタル変換する入力装置と、記憶手段を含むプログラムコントローラー又はコンピューター等の演算処理装置と、演算処理装置からの制御信号をアナログ変換する出力装置とから主に構成される。なお、前述の様な研磨液調製装置（Ｓ１）を設置した場合、上記の制御装置（１０）は、研磨液調製装置（Ｓ１）の各機器の制御を行う制御装置としても利用される。
【００３８】
本発明の供給装置（Ｌ５）は、研磨液調製装置（Ｓ１）の研磨液循環装置（Ｌ４）に流れる研磨液を研磨装置（９）へフィルタ（６２）及び管路（５７）を通じて供給する。また、研磨装置（９）へ研磨液を供給する際、管路（５７）中の研磨液の一部をバイパス管路（５７１）へ供給し、バイパス管路（５７１）の研磨液監視用のパーティクル検出器（８）によって研磨液を監視する。すなわち、バイパス管路（５７１）に設けられたパーティクル検出器（８）は、研磨液が通過するフローセル（８４）に一定波長の光を照射し、所定粒径以上の粒径の砥粒、例えば粒径が３μｍ以上の粒径の砥粒による透過光の減衰を検出することにより、研磨液中の大粒径の砥粒の数を計測する。
【００３９】
その際、流量調整可能なバイパス管路（５７１）にパーティクル検出器（８）が設けられれた構造、および、バイパス管路（５７１）の流量調整によって一定の流速で研磨液が通過可能なフローセル（８４）の構造は、フローセル（８４）における研磨液の流量が制限されると共に、管路（５７）に生じたポンプ等の機器の脈動などによる影響がなく、しかも、フローセル（８４）に流れる研磨液中の所定粒径未満の砥粒の絶対数が低減されるため、受光素子（８５）によって受光したフローセル（８４）の透過光を演算処理手段によって処理した場合、所定粒径未満の粒径の適正な砥粒（粒径が例えば３μｍ未満の砥粒）による透過光の減衰と、所定粒径以上の粒径の砥粒（粒径が例えば３μｍ以上の砥粒）による透過光の減衰とを分離でき、その結果、所定粒径以上の粒径の砥粒の数を正確に計測できる。
【００４０】
また、パーティクル検出器（８）に備えられた校正機能は、上記の大粒径の砥粒による透過光の減衰を検出する際、研磨液中の所定粒径未満の砥粒による感度低下を補正し、大粒径の砥粒による透過光の減衰に対する検出感度を一層高めることが出来る。従って、本発明の供給装置（Ｌ５）は、研磨装置（９）へ供給する研磨液において、所定粒径以上の大粒径の砥粒の発生およびその数をインラインで且つ連続的に、しかも、高精度に管理できる。
【００４１】
本発明の供給装置（Ｌ５）においては、管路（５７）の研磨液を上記の様にインラインで管理することにより、常に高品位の研磨液を研磨装置（９）へ供給できる。例えば、本発明の供給装置（Ｌ５）においては、パーティクル検出器（８）によって検出された所定粒径以上の粒径の砥粒の一定流量当りの数が管理限界を越えた際、警報を発報させる機能が備えられていてもよい。斯かる砥粒の数の管理機能および警報の発報機能は、通常、上記の制御装置（１０）に備えられる。そして、本発明の供給装置（Ｌ５）は、上記の様な発報に伴い、研磨装置（９）への研磨液の供給を停止する様にしてもよい。また、研磨液をインラインで管理することにより、フィルタ（６２）の機能が低下した時点で直ちにフィルタの濾材を交換でき、研磨装置（９）へ供給する研磨液を常に高い品質に維持できる。
【００４２】
また、図示しないが、本発明の供給装置（Ｌ５）において、管路（５７）には、フィルタ（６２）と並列に第２のフィルタが配置されており、パーティクル検出器（８）によって検出された所定粒径以上の粒径の砥粒の一定流量当りの数が管理限界を越えた際、第２のフィルタ側へ流路を切替可能になされていてもよい。すなわち、所定粒径以上の粒径の砥粒を濾過するフィルタが管路（５７）に２系列並列に挿入されていることにより、フィルタ（６２）の機能が低下した場合、機能の低下していない第２のフィルタに直ちに切り替えることができ、運転を停止することなく、常に高い品質の研磨液を研磨装置（９）へ供給できる。
【００４３】
なお、本発明において、管理すべき砥粒の粒径は、研磨条件に応じて適宜に設定し得る。また、上述の様なパーティクル検出器（８）が設けられていることにより、砥粒に限らず、ポンプ、弁などの機器や管路で発生したパーティクル（異物）も管理できる。
【００４４】
【発明の効果】
本発明に係る研磨液の供給装置によれば、光遮断方式の特定のパーティクル検出器が研磨液供給用の管路のバイパス管路に設けられており、所定粒径以上の粒径の砥粒を確実に計測できるため、研磨装置（９）へ供給する研磨液において、所定粒径以上の粒径の砥粒の発生およびその数をインラインで連続的に且つ高精度に管理でき、常に高品位の研磨液を研磨装置へ供給できる。更に、特定の校正機能がパーティクル検出器に備えられている場合には、所定粒径以上の粒径の砥粒の検出感度を一層高めることが出来る。
【図面の簡単な説明】
【図１】本発明に係る研磨液の供給装置の概要ならびに研磨液の供給源の一例としての研磨液の調製装置を示す系統図
【図２】本発明に係る研磨液の供給装置に適用されるパーティクル検出器の原理を一部破断して示す側面図および平面図
【図３】パーティクル検出器のセンサーからの出力および変換された制御用のパルス信号の例を示すグラフ
【符号の説明】
Ｓ１ ：研磨液の供給源（研磨液調製装置）
１ ：原液槽
２ ：調製槽
３ ：研磨液槽
Ｌ４ ：研磨液循環装置
Ｌ５ ：供給装置
５７ ：管路
５７１：バイパス管路
６２ ：フィルタ
８ ：パーティクル検出器
８２ ：光源
８４ ：フローセル
８５ ：受光素子
９ ：研磨装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polishing liquid supply apparatus, and more specifically, for example, a polishing liquid supply apparatus that supplies a polishing liquid for chemical mechanical polishing used for polishing a semiconductor wafer to a polishing apparatus, The present invention relates to a polishing liquid supply apparatus capable of continuously managing in-line the generation of abrasive grains having a particle diameter equal to or larger than a predetermined particle diameter in a polishing liquid.
[0002]
[Prior art]
Semiconductor devices are required to have higher integration, higher speed, and lower power consumption, and in the manufacturing process, in order to further flatten the surface of metal wiring and interlayer insulating film formed on the wafer, For example, a silica-based polishing liquid (CMP slurry) is used, and the surface of the wafer is subjected to chemical mechanical polishing by a polishing apparatus. The polishing liquid used for the polishing process needs to strictly manage the abrasive concentration in order to obtain an accurate polishing rate. In addition, in the polishing liquid, the aggregation of abrasive grains gradually proceeds, and the aggregated large abrasive grains may contribute to the generation of scratches on the wafer, so the size of the abrasive grains in the polishing liquid is managed. Is becoming more important.
[0003]
In the management of the polishing liquid supplied to the polishing apparatus, the polishing liquid is sampled and diluted with pure water, and then irradiated with light of a certain wavelength, and the intensity of the transmitted light and scattered light is measured. The number of abrasive grains having a large particle diameter is measured. The reason for managing the polishing liquid by sampling is as follows. That is, if the abrasive grains in the polishing liquid are to be directly measured on the production line, flow rate fluctuations due to pump pulsation or the like are affected, and therefore the number of abrasive grains cannot be measured accurately. Further, the silica-based polishing liquid as described above has, for example, 10 silica abrasive grains having an average particle diameter of about 0.2 μm. 13 The number of abrasive grains having a very high concentration of particles / ml and a large particle size in question is small. Therefore, even if abrasive grains aggregated to a particle size of 3 μm or more are detected, it is difficult to detect attenuation due to large-diameter abrasive grains by direct measurement due to light attenuation by abrasive grains of appropriate grain size.
[0004]
[Problems to be solved by the invention]
By the way, since it takes a relatively long time to detect abrasive grains having a large particle size in the polishing liquid as described above, the polishing liquid used is actually different from the sampled polishing liquid. In other words, the polishing liquid used contains a larger amount of abrasive grains because the agglomeration further proceeds than when sampling, and as a result, in the polishing process, scratches occur unexpectedly on the wafer. There are things to do.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is a polishing liquid supply apparatus for supplying a polishing liquid for chemical mechanical polishing used for polishing in a semiconductor device manufacturing process. Another object of the present invention is to provide a polishing liquid supply apparatus capable of continuously and in-line managing the generation of abrasive grains having a particle diameter equal to or larger than a predetermined particle diameter in the polishing liquid in-line.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, a polishing liquid supply apparatus according to the present invention is a polishing liquid supply apparatus that supplies a polishing liquid mainly composed of pure water and abrasive grains to the polishing apparatus. A polishing liquid monitor that includes a pipe line extending from the polishing apparatus to the polishing apparatus and a bypass pipe line that can adjust the flow rate, and that detects and counts the number of abrasive grains having a particle diameter greater than or equal to a predetermined particle diameter in the bypass pipe line The particle detector is configured to irradiate the flow cell through which the polishing liquid passes with light having a predetermined wavelength, and to detect the attenuation of transmitted light due to the abrasive grains having a particle diameter equal to or larger than the predetermined particle diameter. It is a shut-off type detector, and the flow cell is configured to allow the polishing liquid to pass at a constant flow rate by adjusting the flow rate of the bypass pipe.
[0007]
That is, in the above supply apparatus, the polishing liquid supplied from the supply source is supplied to the polishing apparatus by the polishing liquid supply pipe, and the particle detector for monitoring the polishing liquid provided in the bypass pipe includes the polishing liquid. Is irradiated with light of a certain wavelength, and the attenuation of transmitted light due to abrasive grains having a particle diameter equal to or larger than a predetermined particle diameter is detected. At that time, the structure in which the particle detector is provided in the bypass pipe whose flow rate can be adjusted, and the structure of the flow cell in which the polishing liquid can pass at a constant flow rate by adjusting the flow rate in the bypass pipe are the flow rate of the polishing liquid in the flow cell. Is not affected by the pulsation generated in the pipeline for supplying the polishing liquid, and the absolute number of abrasive grains less than the predetermined particle diameter in the polishing liquid flowing in the flow cell is reduced. It is possible to separate the attenuation of transmitted light due to the abrasive grains having a particle diameter less than the diameter and the attenuation of transmitted light due to the abrasive grains having a particle diameter greater than or equal to a predetermined particle diameter.
[0008]
Further, in the above supply device, the particle detector corrects a decrease in sensitivity due to the abrasive grains having a particle diameter smaller than the predetermined particle size in the polishing liquid when detecting attenuation of transmitted light due to the abrasive grains having a predetermined particle diameter or larger. It is preferable that a calibration function is provided, and such a calibration function can increase the detection sensitivity with respect to attenuation of transmitted light caused by abrasive grains having a particle diameter equal to or larger than a predetermined particle diameter.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a polishing liquid supply apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing an overview of a polishing liquid supply apparatus according to the present invention and a polishing liquid preparation apparatus as an example of a polishing liquid supply source. FIG. 2 is a partially broken view showing the principle of the particle detector applied to the polishing liquid supply apparatus according to the present invention, wherein a partial view (a) is a side view and a partial view (b) is a plan view. It is. FIG. 3 is a graph showing an example of the output from the sensor of the particle detector and the converted pulse signal for control. In the system diagram of FIG. 1, valves and instrumentation devices are omitted. In the following description of the embodiments, the polishing liquid supply device is simply abbreviated as “supply device” as appropriate.
[0010]
As shown by the symbol (L5) in FIG. 1, the supply apparatus of the present invention is a polishing liquid mainly composed of pure water and abrasive grains, typically, for example, for chemical mechanical polishing applied to polishing of semiconductor devices. Is a supply device for supplying the silica-based polishing liquid (CMP slurry) to the polishing apparatus (9), and abrasive grains having a particle diameter of a predetermined particle diameter or more in the polishing liquid (hereinafter referred to as “large-diameter abrasive grains” as appropriate) It is a device that can manage the number of in-line with high accuracy.
[0011]
In the case of the silica-based polishing liquid, the main components are fumed silica abrasive grains and pure water, and the grain size of the abrasive grains is usually less than 5 μm, preferably less than 3 μm, more preferably 0.1 to 2 μm. In addition, the content of abrasive grains is generally 10 to 30% by weight. Moreover, an additive may be added to the polishing liquid as necessary. The additive may be any component that can oxidize when polishing the surface of the metal wiring or removing the plug, and hydrogen peroxide is generally used. When polishing the silicon layer, an alkali such as potassium hydroxide is used as an additive. These acids or alkalis are added as an aqueous solution through an additive supply device (L3) described later.
[0012]
The polishing apparatus (9) is a so-called well-known constant which continuously polishes the wafer surface by holding the wafer under pressure with the carrier plate so that the surface to be polished is exposed on the lower surface and moving it on the surface plate. The structure of a general polishing apparatus, which is a board apparatus, is described in, for example, Japanese Patent Application Laid-Open No. 2-41869.
[0013]
Specifically, the polishing apparatus holds a plurality of wafers on the same plane level with a table-like surface plate having a polishing cloth mounted on the upper surface and rotating in one direction, and a surface to be polished exposed on the lower surface. A plurality of sets of carrier plates, a center roller provided at the center of the surface plate and accompanied by the surface plate, and a plurality of freely rotatable pieces suspended at regular intervals along the circumferential direction at a fixed position on the outer surface of the surface plate. A set of guide rollers and a plurality of sets of pressure plates (weights) that are supported from above the surface plate and pressurize each carrier plate placed on the surface plate with a constant force toward the surface plate.
[0014]
In the above polishing apparatus, the distance between the center roller and each guide roller is set to be smaller than the diameter of the carrier plate, and each carrier plate holding the wafer is weighted when placed on a rotating platen. The carrier plate itself is also rotated by being pressurized by the center roller and being held at a fixed position by the center roller and the guide roller, and by transmitting the rotational force of the surface plate via the center roller. . That is, in the polishing apparatus, by rotating the surface plate, the polishing cloth is relatively rotated relative to the surface of the wafer, and the polishing process is performed while supplying the polishing liquid.
[0015]
As shown in FIG. 1, the supply device (L5) of the present invention is usually composed of a plurality of supply lines for supplying a polishing liquid to each polishing apparatus (9). A supply line (57) for supplying the polishing liquid from the supply source (S1) to the polishing apparatus (9), and a bypass line (571) whose flow rate can be adjusted by a flow rate adjusting valve (not shown), an orifice or the like. Yes. The bypass line (571) is provided with a particle detector (8) for managing the generation of large-diameter abrasive grains in the polishing liquid supplied to the polishing apparatus (9).
[0016]
As a supply source of the polishing liquid, a portable or fixed storage tank for storing a polishing liquid prepared to a constant abrasive concentration in advance or a polishing liquid prepared to a constant abrasive concentration and added with an additive In general, a polishing liquid preparation apparatus (S1) for preparing a polishing liquid on-site as shown in FIG. 1 is used.
[0017]
First, the polishing liquid preparation apparatus (S1) will be described. The polishing liquid preparation apparatus (S1) generally includes a raw liquid supply apparatus (L1) including a raw liquid tank (1), a preparation tank (2), and a polishing liquid tank (3). And a polishing liquid circulating device (L4). The stock solution supply device (L1) is a device that pumps the slurry stock solution (high concentration polishing liquid) from the stock solution tank (1) to the preparation tank (2), and the piping from the stock solution tank (1) to the preparation tank (2). (51), and a constant flow pump (not shown) such as a bellows type. The stock solution tank (1) is a storage tank for supplying the slurry stock solution to the preparation tank (2), and is constituted by a fixed container or a portable container having corrosion resistance.
[0018]
The preparation tank (2) is a storage tank for adjusting the concentration of the polishing liquid to a predetermined concentration and storing the adjusted polishing liquid. For example, the preparation tank (2) is constituted by a container lined with a fluororesin in order to improve corrosion resistance. Is done. The preparation tank (2) has a measuring device for measuring the weight of the slurry stock solution and pure water to be received, an optical method, a conductivity method, a capacitance method, etc. for measuring the amount of liquid. A total (not shown) is provided. The preparation tank (2) is supplied with a constant concentration of slurry stock solution by a stock solution supply device (L1) and pure water by a pure water supply device (L2) (not shown).
[0019]
The pure water supply device (L2) is a device that supplies pure water for dilution to the preparation tank (2), and is prepared from a known pure water supply apparatus that separates and purifies ultrapure water with an ion exchange resin or the like. ) (52). The pure water supply device (L2) is usually configured to pump pure water produced by the pure water supply device to the preparation tank (2) using a pump attached to the pure water supply device.
[0020]
In the polishing liquid preparation apparatus (S1), the polishing liquid mixed and prepared in the preparation tank (2) is transferred to the polishing liquid tank (3) by the pump (41) and the pipe line (53). In addition, the conduit (53) in the figure is provided with a branch for return flow for monitoring the concentration of the polishing liquid as needed and returning the polishing liquid to the preparation tank (2). Also good.
[0021]
The polishing liquid tank (3) is a buffer tank for supplying the prepared polishing liquid to the polishing apparatus (9), and is supplied with an acid or alkali additive as described above. Consists of a lined, corrosion resistant container. In the polishing liquid tank (4), a liquid level gauge (not shown) capable of measuring points such as an optical type, a conductivity type, and a capacitance type is used to measure the amount of polishing liquid and the amount of additive added. Provided. The polishing bath (3) is supplied with the additive as described above by the additive supply device (L3).
[0022]
The additive supply device (L3) for supplying the additive to the polishing liquid tank (3) is an apparatus for pumping the additive from the separately provided additive tank (not shown) to the polishing liquid tank (3). A conduit for removing the additive from the additive tank (not shown), a metering pump (not shown) for feeding a liquid such as a magnet pump whose flow rate is variable and controllable to a constant flow rate, and a polishing liquid tank ( 3) Consists of a pipe line (55) for supplying the additive to etc.
[0023]
Further, in the polishing liquid tank (3), a stirring mechanism for constantly stirring the polishing liquid may be provided in order to prevent sedimentation and aggregation of the abrasive component. The stirring mechanism is constituted by a rotating device such as a stirring blade, or a jet nozzle (not shown) for generating a di-jet flow attached to the tip on the return flow side of the pipe line (56) of the polishing liquid circulation device (L4). Is done. Although not shown, in the polishing liquid preparation apparatus (S1), a mixing tank is disposed between the preparation tank (2) and the polishing liquid tank (3) in order to increase the mixing efficiency of the polishing liquid and the additive. After the polishing liquid supplied from the preparation tank (2) and the additive supplied from the additive supply device (L3) are mixed in advance in the mixing tank, the polishing liquid to which the additive has been added is added to the polishing liquid tank (3 ) May be stored.
[0024]
The polishing liquid circulation device (L4) maintains a uniform suspension state of the abrasive grains in the polishing liquid stored in the polishing liquid tank (3) and, if necessary, each pipe line ( 57) This is a device for supplying the polishing liquid immediately to the (supply line), and is configured so that the polishing liquid in the polishing liquid tank (3) can be circulated. Specifically, the polishing liquid circulation device (L4) takes out the polishing liquid from the polishing liquid tank (3) and returns the polishing liquid to the polishing liquid tank (3) (56) for circulating the polishing liquid. And it is mainly comprised from the pump (42) which sends polishing liquid, and the filter (61) which filters the abrasive grain of a big particle size. Each storage tank in FIG. 1 can be filled with an inert gas such as nitrogen in order to prevent contact with air.
[0025]
The method for preparing the polishing liquid in the polishing liquid preparation apparatus (S1) is as follows. That is, first, a slurry stock solution having a constant abrasive grain concentration was metered from the stock solution tank (1) to the preparation tank (2), and a predetermined amount of pure water was metered and supplied to the preparation tank (2) by the pure water supply device (L2). Thereafter, the polishing liquid is mixed and prepared in the preparation tank (2). At this time, the abrasive concentration (slurry concentration) of the polishing liquid is adjusted to, for example, 15% by weight by finely adjusting the supply amount of the slurry stock solution or pure water. Then, the polishing liquid prepared in the preparation tank (2) is supplied to the polishing liquid tank (3) through the pipe line (53).
[0026]
Next, the additive as described above is supplied to the polishing liquid supplied to the polishing liquid tank (3) from the additive supply device (L3) through the pipe line (55) as necessary. And an additive is stirred and mixed by said stirring mechanism provided in the polishing liquid tank (3), and a polishing liquid having a predetermined abrasive concentration and a predetermined additive concentration is prepared. The concentration of the additive is determined by supplying a part of the polishing liquid in the pipe (56) of the polishing liquid circulating apparatus (L4) to the concentration measuring apparatus and from the additive supplying apparatus (L3) based on the measurement result. It is adjusted by controlling the supply amount of the additive or the supply amount of the polishing liquid supplied from the pipe line (53).
[0027]
The polishing liquid having a predetermined composition finally prepared in the polishing liquid tank (3) is circulated by the polishing liquid circulation device (L4). That is, by using the pump (42) and the pipe line (56), the polishing liquid taken out from the polishing liquid tank (3) is returned to the polishing liquid tank (3) again, so that the abrasive grains in the polishing liquid are uniform. Maintain suspension. At that time, the filter (61) interposed in the pipe line (56) captures the large-diameter abrasive grains that have been aggregated in the circulating polishing liquid. Thereby, the polishing liquid that does not substantially contain large-diameter abrasive grains can be circulated through the pipe line (56). Then, the polishing liquid in the pipe line (56) is supplied to the polishing apparatus (9) by the supply apparatus (L5).
[0028]
By the way, as described above, the polishing liquid prepared as described above is a liquid in which abrasive grains having a particle diameter of, for example, less than 3 μm are dispersed, and the aggregation of the abrasive grains progresses over time. Therefore, in the supply device (L5) of the present invention, the polishing liquid supplied to the polishing device (9) is managed in-line, and each pipe line (57) is used to prevent the wafer from being scratched by the large-diameter abrasive grains. In the bypass pipe (571), a particle detector (8) for monitoring a polishing liquid that detects and measures the number of abrasive grains having a particle diameter of not less than a predetermined particle diameter, for example, 3 μm or more. Is provided.
[0029]
As described above, when the average particle size of suitable abrasive grains in the silica-based polishing liquid is, for example, less than 3 μm, the particle size may be 3 μm or more due to the progress of aggregation, and in some cases, it may be several μm or more. The number of such large-diameter abrasive grains is extremely small compared to the number of abrasive grains having an appropriate particle diameter in the polishing liquid. For example, when the average grain size of appropriate abrasive grains in the silica-based polishing liquid is about 0.2 μm, the number is 10 13 The number of large-diameter abrasive grains that cause scratches is about 10 to 1000 pieces / ml. Therefore, as the particle detector (8), a light blocking method for irradiating the flow cell (84) through which the polishing liquid passes with light of a certain wavelength and detecting attenuation of transmitted light due to abrasive grains having a particle diameter equal to or larger than a predetermined particle diameter. Detectors are used.
[0030]
The basic structure of a light blocking detector is known, and such a detector has a structure that irradiates light (slurry) flowing through a transparent flow cell and detects the amount of transmitted light by a light receiving element. The size of the particles is measured by reducing the amount of light due to light absorption, reflection or scattering by the particles passing through the flow cell, and the number of particles is measured by the number of changes in the amount of light obtained as a pulse. Yes.
[0031]
Specifically, as shown in FIG. 2, the main part of the particle detector (8) is a tungsten lamp, a light emitting diode, a semiconductor laser, etc. that emits light of a certain wavelength by the power supplied by the power supply circuit (81). Light source (82), a condensing lens (83) that condenses the light emitted from the light source (82) into, for example, a flat belt-like light beam, and a transparent material such as quartz glass, for example, is formed in a cylindrical shape with a rectangular cross section. Flow cell (84), a photodiode for detecting the intensity of light transmitted through the light source (82) that has passed through the flow cell (84), a light receiving element (85) such as an optical array, and an output signal of the light receiving element (85) It comprises an amplifier (86) for amplifying, and arithmetic processing means (arithmetic circuit including a storage / arithmetic element) for arithmetically processing the signal of the light receiving element.
[0032]
In general, in the measurement of abrasive grains having a large particle size in the polishing liquid, as described above, a very small number of abrasive grains in the polishing liquid having an abrasive concentration of, for example, 10 to 30% by weight must be detected. Therefore, depending on the setting of the lower limit of the particle size of the large abrasive grain to be detected, the influence (noise) due to light absorption, reflection or scattering by the appropriate abrasive grain is large, and the large abrasive grain is accurately Hard to detect. Further, when the fluid is pulsated by a device such as a pump, the number of particles cannot be measured accurately.
[0033]
On the other hand, in the present invention, by providing the particle detector (8) in the bypass pipe (571) whose flow rate is limited, the influence of pulsation in the pipe (57) for supplying the polishing liquid is prevented, And the influence (noise) by the abrasive grain of a suitable particle size is reduced, and the accurate detection of the abrasive particle of a large particle size with few numbers is enabled. That is, the flow cell (84) is configured to allow the polishing liquid to pass at a constant flow rate by adjusting the flow rate of the bypass pipe line (571). Usually, the flow rate of the polishing liquid in the flow cell (84) is set to 1 to 500 ml / min, and the flow rate is set to 0.1 to 1 m / sec. Further, in order to detect abrasive grains having a large particle size more accurately, the light transmission distance in the flow cell (84) is preferably set to 0.1 to 100 mm.
[0034]
Furthermore, in the manufacturing apparatus of the present invention, in order to detect the abrasive grains having a large particle size in the circulating polishing liquid with higher accuracy, the particle detector (8) has a particle having a predetermined particle diameter or larger. When detecting the attenuation of transmitted light due to the abrasive grains having a diameter, a calibration function is provided to correct a decrease in sensitivity due to abrasive grains having a grain size smaller than a predetermined grain size (abrasive grains having an appropriate grain size) in the polishing liquid. Such a calibration function is usually provided in the arithmetic processing means.
[0035]
That is, as shown in FIG. 3A, in the particle detector (8), the light receiving element (85) outputs the received light signal as a pulse signal, but the above arithmetic processing means was obtained. After the pulse signal is processed into a waveform as shown in FIG. 3B, a signal higher than the lower limit threshold voltage preset by the standard sample is counted. The above standard sample includes a certain amount (for example, 15% by weight) of abrasive grains having a predetermined particle diameter (for example, abrasive grains having a particle diameter of less than 3 μm) and the same particle diameter as that to be detected (for example, 3 μm). A polishing liquid added with polystyrene latex particles as standard particles is used.
[0036]
Furthermore, in the supply device (L5) of the present invention, the pipe (57) is provided with particles having a predetermined particle diameter or larger so that a higher quality polishing liquid can be supplied to the polishing device (9). A filter (62) that captures abrasive grains having a diameter, for example, abrasive grains having a particle diameter of 3 μm or more is disposed upstream of the particle detector (8). As such a filter (62), a normal fluid filter provided with a depth type filter medium made of polypropylene having a pore diameter of about 1.0 to 5.0 μm is used.
[0037]
The control device (10) illustrated in FIG. 1 is a control device that controls the opening and closing of the valves of the supply device (L5). The control device (10) is a program controller that includes an input device that digitally converts device signals and a storage means. It is mainly composed of an arithmetic processing device such as a computer and an output device that converts a control signal from the arithmetic processing device into an analog signal. When the polishing liquid preparation apparatus (S1) as described above is installed, the control apparatus (10) is also used as a control apparatus for controlling each device of the polishing liquid preparation apparatus (S1).
[0038]
The supply device (L5) of the present invention supplies the polishing liquid flowing in the polishing liquid circulation device (L4) of the polishing liquid preparation device (S1) to the polishing device (9) through the filter (62) and the pipe line (57). Further, when supplying the polishing liquid to the polishing apparatus (9), a part of the polishing liquid in the pipe line (57) is supplied to the bypass pipe (571) to monitor the polishing liquid in the bypass pipe (571). The polishing liquid is monitored by the particle detector (8). That is, the particle detector (8) provided in the bypass line (571) irradiates the flow cell (84) through which the polishing liquid passes with light of a certain wavelength, and abrasive grains having a particle diameter equal to or larger than a predetermined particle diameter, for example, The number of abrasive grains having a large particle diameter in the polishing liquid is measured by detecting the attenuation of transmitted light by the abrasive grains having a particle diameter of 3 μm or more.
[0039]
At that time, a structure in which the particle detector (8) is provided in the bypass conduit (571) capable of adjusting the flow rate, and a flow cell (through which the polishing liquid can pass at a constant flow rate by adjusting the flow rate of the bypass conduit (571)). In the structure of 84), the flow rate of the polishing liquid in the flow cell (84) is limited, there is no influence by the pulsation of equipment such as a pump generated in the pipe line (57), and the polishing flowing in the flow cell (84). Since the absolute number of abrasive grains less than a predetermined particle diameter in the liquid is reduced, when the light transmitted by the flow cell (84) received by the light receiving element (85) is processed by the arithmetic processing means, the particle diameter less than the predetermined particle diameter. Attenuation of transmitted light by appropriate abrasive grains (abrasive grains having a particle diameter of less than 3 μm, for example) and attenuation of transmitted light by abrasive grains having a particle diameter of a predetermined particle diameter or more (abrasive grains having a particle diameter of, for example, 3 μm or more) Can be separated As a result, the number of abrasive grains having a particle diameter equal to or larger than a predetermined particle diameter can be accurately measured.
[0040]
In addition, the calibration function provided in the particle detector (8) corrects a decrease in sensitivity due to abrasive grains having a particle size less than a predetermined size in the polishing liquid when detecting attenuation of transmitted light due to the above-mentioned large-diameter abrasive particles. In addition, it is possible to further increase the detection sensitivity with respect to the attenuation of transmitted light due to the large-diameter abrasive grains. Therefore, the supply device (L5) of the present invention, in the polishing liquid supplied to the polishing device (9), the generation and number of abrasive grains having a large particle size of a predetermined particle size or more are continuously generated in-line, It can be managed with high accuracy.
[0041]
In the supply apparatus (L5) of the present invention, the polishing liquid in the pipe line (57) is managed in-line as described above, so that a high-quality polishing liquid can always be supplied to the polishing apparatus (9). For example, in the supply device (L5) of the present invention, an alarm is generated when the number of abrasive grains having a particle size larger than a predetermined particle size detected by the particle detector (8) exceeds a control limit. A function for reporting may be provided. Such a control function of the number of abrasive grains and an alarm issuing function are usually provided in the control device (10). And the supply apparatus (L5) of this invention may make it stop supply of the polishing liquid to a polishing apparatus (9) with the above reports. In addition, by managing the polishing liquid in-line, the filter medium of the filter can be replaced immediately when the function of the filter (62) is lowered, and the polishing liquid supplied to the polishing apparatus (9) can always be maintained in high quality.
[0042]
Although not shown, in the supply device (L5) of the present invention, the pipe (57) is provided with a second filter in parallel with the filter (62), and is detected by the particle detector (8). Alternatively, the flow path may be switched to the second filter side when the number of abrasive grains having a grain size equal to or larger than a predetermined grain size per control flow rate exceeds a control limit. That is, when the function of the filter (62) is deteriorated by the fact that the filter for filtering the abrasive grains having a particle diameter equal to or larger than the predetermined particle diameter is inserted in two lines in the pipe line (57), the function is deteriorated. It is possible to immediately switch to the second filter that is not present, and to always supply a high-quality polishing liquid to the polishing apparatus (9) without stopping the operation.
[0043]
In the present invention, the grain size of the abrasive grains to be managed can be appropriately set according to the polishing conditions. Further, by providing the particle detector (8) as described above, it is possible to manage not only abrasive grains but also particles (foreign matter) generated in devices such as pumps and valves and pipes.
[0044]
【The invention's effect】
According to the polishing liquid supply apparatus of the present invention, the specific particle detector of the light blocking method is provided in the bypass pipe of the polishing liquid supply pipe, and the abrasive having a particle diameter equal to or larger than a predetermined particle diameter. In the polishing liquid supplied to the polishing device (9), the generation and number of abrasive grains with a particle size larger than the predetermined particle size can be managed continuously and with high accuracy in-line. Can be supplied to the polishing apparatus. Furthermore, when a specific calibration function is provided in the particle detector, it is possible to further increase the detection sensitivity of abrasive grains having a particle size greater than or equal to a predetermined particle size.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an overview of a polishing liquid supply apparatus according to the present invention and a polishing liquid preparation apparatus as an example of a polishing liquid supply source;
FIGS. 2A and 2B are a side view and a plan view, partially broken away, showing the principle of a particle detector applied to a polishing liquid supply apparatus according to the invention.
FIG. 3 is a graph showing an example of an output from a sensor of a particle detector and a converted pulse signal for control.
[Explanation of symbols]
S1: Polishing liquid supply source (polishing liquid preparation apparatus)
1: Stock solution tank
2: Preparation tank
3: Polishing bath
L4: Polishing liquid circulation device
L5: Supply device
57: Pipe line
571: Bypass pipeline
62: Filter
8: Particle detector
82: Light source
84: Flow cell
85: Light receiving element
9: Polishing device
Claims (5)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000351097A JP3789297B2 (en) | 2000-11-17 | 2000-11-17 | Polishing fluid supply device |
| US09/986,988 US6709313B2 (en) | 2000-11-17 | 2001-11-13 | Apparatus for producing polishing solution and apparatus for feeding the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000351097A JP3789297B2 (en) | 2000-11-17 | 2000-11-17 | Polishing fluid supply device |
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| Publication Number | Publication Date |
|---|---|
| JP2002154057A JP2002154057A (en) | 2002-05-28 |
| JP3789297B2 true JP3789297B2 (en) | 2006-06-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000351097A Expired - Lifetime JP3789297B2 (en) | 2000-11-17 | 2000-11-17 | Polishing fluid supply device |
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| JP (1) | JP3789297B2 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030010792A1 (en) | 1998-12-30 | 2003-01-16 | Randy Forshey | Chemical mix and delivery systems and methods thereof |
| FR2883971B1 (en) * | 2005-03-31 | 2007-11-16 | C2 Diagnostics Sa | OPTICAL BLOOD ANALYSIS DEVICE, ANALYZING APPARATUS EQUIPPED WITH SUCH A DEVICE |
| JP4796807B2 (en) * | 2005-09-06 | 2011-10-19 | Ｓｕｍｃｏ Ｔｅｃｈｘｉｖ株式会社 | Semiconductor wafer polishing method |
| JP6352143B2 (en) * | 2013-11-13 | 2018-07-04 | 東京エレクトロン株式会社 | Substrate liquid processing apparatus and substrate liquid processing method |
| JP6295107B2 (en) | 2014-03-07 | 2018-03-14 | 株式会社荏原製作所 | Substrate processing system and substrate processing method |
| JP6939043B2 (en) * | 2017-04-21 | 2021-09-22 | 東京エレクトロン株式会社 | Processing liquid supply device |
| CN110227294B (en) * | 2019-06-17 | 2024-04-19 | 中国工程物理研究院激光聚变研究中心 | Polishing solution circulating and filtering system |
| US20220362902A1 (en) * | 2021-05-14 | 2022-11-17 | Taiwan Semiconductor Manufacturing Company Ltd. | Method and system for slurry quality monitoring |
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2000
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