JP4415067B2 - Method and apparatus for treating an object with a chemical solution - Google Patents

Description

【０００７】
表１は、強酸性薬液で洗浄処理を始めてから各工程が推移するのに連れて外槽のｐＨ（水素イオン濃度）値の変化を観察したもので、当初のｐＨ値は７．２でおよそ中性であるのに対して漸次ｐＨ値が下がり続け中性から弱酸性へと変化し、やがて強酸性へと変化している様子が読み取れ、液封液中に薬液から飛散した強酸性の微粒子が吸着されていることが理解できる。以上、図６に示す従来の装置によれば薬液雰囲気が直に薬液槽周囲に漏れだして処理室を汚染する問題は回避される一方で、液封液から微粒子が空気中に飛散して空気汚染を引き起こす問題は非常に深刻で、このような空気汚染をも解消するためには液封液の外でも強制排気が必要になる。つまり、結局のところ図６の装置を用いたとしても液中微粒子の空気飛散を防ぐことを徹底しようとすれば、大容量の排気施設を備えねばならず、装置が大がかりになってしまうという問題においては、図５に示される一般的な従来型装置の場合と大差がない。以上、いずれの従来技術を用いたとしても、洗浄エリアで使用する汚染源の薬液雰囲気を回避するために多大な容量の排気施設を備えねば依然として汚染の懸念は拭えず、微細な装置を処理することも処理に従事する作業者が安全に処理することも難しいという問題がある。
【０００８】
本発明は、以上の従来技術の抱える問題点を解決しようとしてなされたものであり、洗浄エリアから外部への汚染を阻止し、外部開放部液封液のクリーン度を維持し、多大な排気を削減するとともに、汚染源である薬液等の噴霧による洗浄までを可能とすることを課題とする。
【０００９】
【課題を解決するための手段】
上記の課題の解決のため、本発明では、例えば以下の構成を手段とする。
【００１０】
薬液槽内にて薬液を溜めて行なう半導体基板やマスク・レチクル基板、各種ガラス基板等の物体の洗浄等薬液処理方法であって、該薬液槽の上部を覆い、且つ、該薬液漕の直上に排気口が設けられた蓋と、純液の供給を受け、該蓋につながった仕切りで液水面が区分され、該仕切りよりも前記蓋の内側に向け壁面を伝って前記液が溢れ出るように構成される外槽と、底面に設けられた吸気口から不活性ガスが導入されるとともに、前記溢れ出た液を回収し、前記溢れ出るよりも十分速く排水路を通して外へ導く中間槽とを用いて行なう物体の薬液による処理方法。前記外槽のうち前記仕切りの外部において強制排気を行なうことが好ましい。
【００１１】
以下、図１，図２を順次引用しつつ上記の手段をより詳しく説明する。
図１参照。
【００１２】
図１は、本発明の第一の実施態様に基づく薬液処理装置要部の模式図である。図中の薬液槽には、半導体基板の洗浄に用いる薬液が蓄えられており、薬液槽の上部は蓋で覆われているので、この薬液槽の上部に飛散する薬液雰囲気は、薬液槽に隣接する中間槽方向へと飛散する。一方、中間槽はさらに外側で外槽と隣接する構成であり、外槽には純水が液封液として蓄えられていて、この液封液表面を二分するように仕切りが設けられていて、この仕切りが蓋と接続して薬液雰囲気が直に外には漏れ出ることのないように構成されている。外槽に蓄えられた液封液は仕切りの外から一定流量で給水され、それに伴って仕切りの内側の壁面を伝って中間槽へと流れ落ちるように構成しているから、薬液雰囲気は液封液に溶けたとしても中間槽へと流れ落ちて給水量よりも著しく速い勢いで排水されるから、装置周辺の雰囲気を汚染することはなくなる、というものである。
図２参照。
【００１３】
図２は、本発明の第二の実施態様に基づく薬液処理装置要部の模式図である。図２の装置では、図１の装置の場合に加えて、薬液雰囲気の排気が中間槽側に入り込まないように、強制的に中間槽側から薬液槽に向けての気流を強制生成する工夫が施されている点が特徴的である。図２の装置では、中間槽の下側から窒素が吹き込まれる。窒素を選ぶ理由は不活性だからであるが、窒素に代えてアルゴン等の不活性ガスを用いることでも良い。薬液槽上に設けられた排気部では、導入された窒素ガスも薬液雰囲気と一緒に排気される構成になっていて、窒素の導入量よりも大幅に上回るような排気量を有する構成として中間槽側へは薬液槽内の雰囲気が入り込まないようにして、薬液微粒子の外槽内液封液への汚染を完全に避けることができる。
【００１４】
【発明の実施の形態】
それでは、本発明の一実施形態を以下説明する。
再び図１参照。
【００１５】
図１は、本発明の第一の実施態様に基づく薬液処理装置要部の模式図であり、装置要部の断面を示す。図１中、薬液槽２の外周には、薬液槽２の上を覆う蓋１の端部を液封シールするための液封槽部が装備されている。この液封槽部は、外槽３と中間槽４からなり、外槽３の中に貯えた液封液面よりも蓋１の端が下に沈むようにしておき、液封液面でシールする構成である。この外槽３は図示しないが薬液槽２の周囲を取り囲むように配置されていて、外槽３へは外から常に液封液給水口５０１から純水が導入されて、外槽３から中間槽４へと両者の境界壁を伝って溢れ出て、中間槽４の下面から液封液排水口５０２へと回収される。この間、薬液槽２から飛散する薬液雰囲気は、液封液面に触れて液封液中に吸着されると、液封液に溶けたまま液封液排水口５０２から外へと排出される。
図2参照。
【００１６】
次に図２は、本発明の第二の実施態様に基づく薬液処理装置要部の模式図であり、装置要部の断面を示す。図２中、薬液槽２０の外周には、薬液槽２０の上を覆う蓋１０の端部を液封シールするための液封液面でシールする。この外槽３０は図示しないが薬液槽２０の周囲を取り囲むように配置されていて、外槽３０へは外から常に液封液給水口５１１から純水が導入されて、外槽３０から中間槽４０へと両者の境界壁を伝って溢れ出て、中間槽４０の下面から液封液排水口５１２へと回収される。この間、薬液槽２０から飛散する薬液雰囲気は、液封液面に触れて液封液中に吸着されると、液封液に溶けたまま液封液排水口５１２から外へと排出される。以上の点においては、図１の装置の場合と変わらないが、加えて図２の装置の場合には、薬液槽２０の直上に排気口４０１を備え、さらにＮ₂パージ口を中間槽４０の底に備えて、強制的に排気の流れをつくり出している点が異なる。このように窒素の導入量よりも大幅に上回るような排気量を有するように構成すれば、強制的に中間槽側から薬液槽に向けての気流を生成でき、中間槽側へは薬液槽内の雰囲気が入り込まず、薬液微粒子の外槽内液封液への汚染さえも避けることができ、不意に薬液雰囲気が排出されてしまう問題の解消にはいっそう効果が高くなる。なお、パージガスとして窒素を選んだ理由は、窒素が不活性であるからに過ぎず、例えばアルゴン等の他の不活性ガスにて代用することは可能である。
【００１７】
ところで、薬液雰囲気が排出されて装置周辺を汚染することがなおも問題となる場合には、徹底的にその原因を全て絶つことが必要になってくる。このような目的に沿って薬液槽にて薬液処理を行う前後には必ず装置内部を純水洗浄することが望ましい。半導体デバイス等微細な装置の洗浄等薬液処理にはこのような純水洗浄は必須であろう。薬液槽（図１の場合「２」，図２の場合「２０」）や中間槽（図１の場合「４」，図２の場合「４０」）の中に、それぞれの槽の壁面を洗うためのシャワーノズルを備えておき、薬液処理を始める前と終わった時にはそれぞれシャワーノズルから純水を吹き出させて、槽の壁面を念入りに洗浄するのが良い。蓋（図１の場合「１」，図２の場合「１０」）にも汚染されたミストが付着する場合があるので、シャワーノズル洗浄を行うのであれば、蓋に対しても純水を吹き出させて洗浄するのが良い。
図４参照。
【００１８】
薬液雰囲気による汚染を低減するために、蓋を処理槽中央に落ち込む形状にした方が効果的であるので、このことについて図４を引用しつつ以下説明する。図４は、本発明の第一の実施態様による薬液処理装置の模式図であり、装置の断面を示す。
【００１９】
図４において、他の図面での部品番号と同じ番号を振られた部品は、同じものを示す。薬液槽２の直上に覆いかぶさる蓋１００はテーパー形状をなしているので、シャワーノズルを用いて蓋１００を洗浄する際には、吹き出された純水は蓋の内面に当たった後、テーパーに沿って薬液槽２中央に落ちることとなって、蓋１００内面に付着して残る雫に薬液雰囲気が溶け込んだ後、再び周囲に飛散して汚染してしまうことも解消されるので、薬液雰囲気による汚染低減の効果はさらに高まる。加えて、蓋をテーパー形状にしたため、薬液槽２を満水状態にして洗浄する場合には、蓋の真下に気泡溜まりができるのを防ぐことができ、したがって満水洗浄の効果を蓋に対しても有効に作用させることができる。
【００２０】
さらに、図４の装置では、蓋１００の角部付近から斜面をなし、先端が中間槽４に向けて伸びる板材１０５を備える。この板材１０５は、シャワーノズル洗浄時に流れ落ちる液滴が外槽３には落ちず中間槽４内に落ちるように誘導する働きがあるので、汚染された液滴が外槽３内に入り込んで周囲の雰囲気を汚染する問題を低減するのに寄与する。
以上のように、本発明では、薬液雰囲気が外部に拡散しない液封内部を局部排気することとなるので、排気量を大幅に削減できる。蓋を有しない図５に示される従来のドラフトと比べても、排気量は８５％以上削減できる。図６に示される従来の液封技術と比べても、同じ酸性薬液での処理に対して液封液の汚染は、従来ｐＨ（水素イオン濃度）２前後であったのをｐＨ５前後まで改善できる。
図３参照。
【００２１】
次に、図３を引用しつつ、シリコンウエハを薬液槽に漬けて洗浄する場合を例に、薬液処理システム全体の給排水、給排気系統を作動順序に沿って説明する。図３は、本発明の第一の実施態様による薬液処理システムの構成図であり、９１〜９４，９６〜９１４はバルブ，２は薬液槽、３は中間槽、４は外槽である。薬液槽２の上には蓋１００が覆い被さり、蓋１００の角付近から板材１０５が伸びている構成は、図４に示すものと同じである。洗浄を始める前に、先ずバルブ９１を開いて液封液として純水を外槽３内に流し込むとともに、バルブ９２を開いて不活性ガス、例えば窒素を給気を行なう。
【００２２】
洗浄を開始する前に、まずバルブ９１を開いて液封液として純水を外槽に流し込んで下から上への水流を安定させるとともに、バルブ９２を開いて給気を行い外槽から薬液槽への気流を安定させる。この気流によって薬液槽からの薬液ミストの槽外への拡散を防ぎます。また、防ぎきれなかったミストは水流により装置外拡散を防ぐため、バルブ９１，９２は洗浄処理が完了するまで開きつづけます。
【００２３】
治具やウエハあるいはマスク基板等の被洗浄物は、蓋１００に直付けられた籠の中に作業者が入れて、籠ごと徐々に薬液中に浸漬される。次に、外槽３中に純水を流して液封液の流れが安定したのを確認した後、窒素（Ｎ₂）ガスを蓋１００上で中間槽4の真上の位置に設けられる給気口から導入して密閉した蓋１００の内側に流す。窒素（Ｎ₂）ガスを導入することによって中間槽４内が陽圧になり、薬液雰囲気が薬液槽２から中間槽４へと流れ込むのを防ぐことができます。
【００２４】
次に、バルブ９１，９２を開いたままで、薬品１（過酸化水素水），薬品２（アンモニア水），薬品３（塩酸水溶液），薬品４（フッ酸水溶液），薬品５（硝酸水溶液）を秤量し、必要量分だけバルブ群３中の各バルブを開いて薬液槽2内に導入する。薬液槽２中に導入すべき洗薬液の調合は次の要領で行う。一般的に工場内各所には高濃度の溶液が配管を通して流れているため、実際に薬液処理装置に対しても高濃度の溶液のまま導入し、これを薬液処理装置内で希釈して使うのが簡便である。しかし、薬液の濃度が高ければ高いほど薬液の揮発性は高くなるのが一般である。したがって、高濃度の薬液を薬液処理装置に導入した後に希釈する方法よりも先ず純水を薬液処理装置に導入し次いで高濃度の薬液を導入して希釈することの方が望ましい。例えば、１０％ＨＦ（フッ酸）溶液を１０リットル調合する場合、工場供給時のＨＦ（フッ酸）溶液濃度が５０％と高いため揮発性も高く、薬液雰囲気の飛散の可能性が高まる。従ってまず希釈用純水を約４リットルまで溜め、その後５０％ＨＦ（フッ酸）を約２リットルまで入れる。最後に攪拌用純水を約４リットルまで入れて調合完了とする。
【００２５】
具体的なバルブ動作は、薬液槽内での１０％ＨＦ（フッ酸）溶液を約１０リットル調合するにあたり、先ずバルブ９１３を開いて純水を規定レベル１（約４リットル供給）まで導入後、バルブ９１３を閉じる。続いてバルブ９３群の薬品４系統のバルブを開き５０％ＨＦ（フッ酸）を規定レベル２（約２リットル供給）まで導入後、バルブ９３群の薬液４系統のバルブを閉じる。最後に攪拌のためにバルブ９１３を開いて純水を規定レベル３（約４リットル）まで導入後、バルブ９１３を閉じて調合は完了する。
【００２６】
希釈用及び攪拌用の純水の規定量はレベルセンサによって検出する。純水は薬液に比べて大流量供給が可能なので攪拌に向いています。実際にはこの後循環シャワー洗浄するので純水を２回に分けて供給しなくても実害はない。攪拌の方法としてはこの他Ｎ₂（窒素）バブリングもあり、純水による二段階の希釈に置き換え、希釈純水量を当初から８リットルとして、これに対してＮ₂バブリングを行っても良い。また、Ｎ₂（窒素）に代えて他の不活性ガスを用いることもできる。
【００２７】
次に、一定量の薬品１〜５が薬液槽内に導入された後に、バルブ群３は全て閉じる。
【００２８】
続いて、循環シャワーを開始すべく、バルブ９１，９２は開いたままで、新たにバルブ９６，９７およびバルブ９４を開き、かつバルブ９４につながるポンプ９５を作動させて薬液槽２の下から排出した薬液（１０％ＨＦ（フッ酸）溶液）をバルブ９６，９７を通して再び薬液槽２内に循環させて、薬液槽２内壁面に向けて噴射する。薬液槽２に溜めた薬液をポンプで循環してスプレーノズルから薬液を被洗浄物に噴射して薬液処理する。このような循環シャワーを５分間続けた後、さらに１０分間同じ循環シャワーを続け、さらに１５分間循環シャワーを行ない、続いて２０分間循環シャワーを行なった後に、循環シャワーを２５分間行なう。全ての一連の循環シャワー動作が終了した後で、ポンプ９５を停めて、バルブ９４，９６，９７を閉めた後、バルブ９８，９９を開き、薬液槽２から薬液を排水として排水路１〜３に排出する。この際、排水は排水路１〜３に三分されるが、排水１はフッ酸用排水，排水２は一般酸排水（フッ酸以外の薬液），排水３は純水回収（水洗用純水の排水である程度純度を上げるべく工場内の再生処理施設に回収し、再び純水として再利用するためのもの）である。なお、上記の循環シャワー動作でより清浄な薬液処理を望む場合には、バルブ９４とポンプ９５との間に濾過フィルターを設けておき、濾過後の薬液を循環させることにしても良い。
【００２９】
次に、バルブ９８，９９は閉じて排水の排出を終わった後で、バルブ９１，９２は依然として開いたままで、バルブ９１０を開き、薬液槽２の外側で蓋１００の裏面に対して純水のシャワーを浴びせて蓋１００の内側を洗浄する。中間槽４と外槽３の上にある部分の蓋１００の水洗を行う。
【００３０】
次に、バルブ９１０を閉じ、続いてバルブ９１１を開き、薬液槽２の内側で蓋１００の裏側に対して純水のシャワーを浴びせて蓋１００の内側を洗浄する。薬液槽２の上にある部分の蓋１００の水洗を行う。
【００３１】
バルブ９１１を閉じた後で、依然バルブ９１，９２は開いたままの状態で、バルブ９６，９７，９１２を開いて、純水を薬液槽２の内壁面にシャワー噴射する。薬液槽２内部とシャワーノズル部を水洗する他、被洗浄物も不完全ながら水洗する。例えばＨＦ（フッ酸）溶液の場合などは、薬液付着のまま放置すれば被洗浄物表面が荒れてしまうので、それを避けるために一旦仮にノズル洗浄する。また、各薬液と共用している配管なので、異なる薬液どうしが混ざって化学反応一つの洗浄混合液ごとに水洗しないと前の混合液（例えばＨＦ（フッ酸）溶液）と次の混合液（過酸化水素＋アンモニア溶液）が混ざって化学反応を起こしてしまう。
【００３２】
バルブ９６，９７，９１２を全部閉じて、このワークシャワー動作が終わった後で、薬液槽２の外側で蓋１００の内側に向けて再び純水をシャワー噴射して蓋１００の内側を洗浄する。続いて、バルブ９１０を閉じバルブ９１，９２は開いたままでバルブ９１１を新たに開いて、薬液槽２の内側で蓋１００の内側に向けて純水をシャワー噴射して蓋１００の内側を洗浄する。次にバルブ９１２は閉じて蓋１００の洗浄を終わり、再びワークシャワーを行なう。バルブ９１，９２は開いたままで、バルブ９６，９７，９１２を開いて行なう。薬液の調合用配管とシャワー洗浄用循環ポンプ配管の水洗を行うためである。
【００３３】
薬液槽２内の液（水＋ＨＦ（フッ酸））を排水する。
【００３４】
被洗浄物及び薬液槽２を水洗する。被洗浄物の形状次第では、液が溜まったり、溝部に薬液が残ってしまい、シャワー洗浄だけだと薬液を完全に水洗（水置換）できない場合があるため薬液槽２に純水をためて水洗することで完全な水置換が出来るようになる。また、薬液槽２はＰＶＣ（塩化ビニル）製なので長時間の間薬液に触れた場合にはＰＶＣ分子間に薬液が残留しがちで、シャワー洗浄よりも薬液槽２の中に純水を貯めた方が有効に水洗効果を上げることができる。しかし、薬液槽２中に純水を貯める方法をもってしても、ＰＶＣ分子間に入り込んだ薬液を完全除去することは難しいため、薬液雰囲気による汚染原因を根本的に絶つためには、薬液槽２の素材としてＰＶＣを採用しないことが最良である。温水水洗＋室温水水洗の二段階洗浄を採用すれば、単に室温水のみで水洗する場合よりも、薬液槽２自体を洗浄する効果が高まることもわかっており、特にＰＶＣを薬液槽２の素材として使用するのであれば、温水水洗＋室温水水洗を採用することが望ましい。
【００３５】
次に薬液槽２を満水にする。被洗浄物、薬液槽２の水洗も行うが、シャワーではねた薬液が蓋１００に付着する場合があるので、薬液槽２の上の部分の蓋１００を水洗することが目的である。これもシャワーより漬かる（構造的に薬液槽２とわずかな隙間しかないため薬液槽２から純水を溢れさせると蓋１００の全面が水に浸かるようになる）方が水洗効果が高いためである。
【００３６】
薬液槽２から液の排水を始める。ほぼ、純水レベルなので排水は純水回収（排水３）になります。
【００３７】
次に、薬液槽２の乾燥を始める。薬液槽２内が清浄な状態で被洗浄物を自然乾燥させます。バルブ９１を開けて液封液となる純水を導入するが、目的は液封シールによる外部との遮断にあるだけなので、ｐＨ（水素イオン濃度）値が７．０に近いことが判り液封液の純度が純水の状態にあることが明らかな場合には、新たにバルブ９１を開いて純水を流し入れる必要はないから、この場合にはバルブ９１を開かなくても良い。液封液が汚染されているようであれば、バルブ９１を開いて新しく純水を流し入れる。Ｎ₂（窒素）を密閉した蓋１００の内側に流して、薬液槽２内を陽圧にすることで排水管、排気から薬液雰囲気が薬液槽２に流れてくるのを防ぐことができる。次にバルブ９８，９９を開いて薬液槽２から排水を行う。ほぼ純水レベルなので排水は純水回収（排水３）になります。
【００３８】
次に被処理物を入れた籠を引き上げる。十分に蓋１００側に引き上げた後に、蓋１００を開いて籠の中にある被処理物を取り出す。この際にバルブ９１を開けて液封液となる純水を導入しても良い。前工程におけると同様、液封液のｐＨが変化していて液封液の純度が下がっていることが確認できている場合には、このようにバルブ９１を開いて純水を導入することに意味がある。バルブ９２はＮ₂（窒素）ガスを密閉した蓋の内側に流す。流すガスは、Ｎ₂（窒素）に代えてアルゴン等の他の不活性ガスを用いることも良い。このように、バルブ９１を開いて不活性なガスを流すことは、薬液槽内を陽圧にすることで、排水管や排気から薬液ガスが薬液槽へと逆流することを防ぎ、かつ蓋を開ける動作をスムーズにできるという効果がある。
【００３９】
以上の本発明の実施態様の説明においては、外槽蓋のシャワー洗浄と、内槽蓋のシャワー洗浄と、ワークシャワーとをそれぞれ別々に分けて行っている。その理由は下記の通りである。
理由その１）
３つのシャワーから同時に純水を出すと各シャワーから出る純水の流量が落ちてしまい、その結果、純水が蓋や薬液槽の全面にかからず、洗浄すべき領域全面に純水がかからないという問題が出てくる場合があるためである。
理由その２）
蓋は２３番目のオーバーフロー水洗（蓋を水に漬けて洗う）時、泡が蓋の表面につかないようにするために薬液槽部が低く外槽部が高い船底のような緩やかなテーパーを四面につけている。しかし、１１番目の内槽蓋シャワーは勢いが強い（強くないと大きな蓋の全面が洗えない）ためテーパーに逆らって内槽から外槽方向にシャワーの洗浄水（純水＋薬液）が流れていき、水封水の汚染につながる可能性がある。したがってまず外槽シャワーで外槽から処理槽方向に純水をかけて蓋についた薬液をできるだけ薬液槽に洗い落とす。その後内槽蓋シャワー＋ワークシャワー（薬液槽の水洗）を行うことが望ましい。外槽シャワー後に内槽シャワーとワークシャワーを同時に行っても問題ないし、３つのシャワーを同時に流してもより汚染を低減できる。
【００４０】
また、洗浄動作を繰り返すのは以下の理由による。
【００４１】
各シャワー水洗の各部分を３つのシャワーで各々別々に分けて洗うため、繰り返したほうが水洗ムラは少ない。
【００４２】
以上の他、薬液処理工程の前後では、薬液槽の壁の水洗，給液配管や循環ポンプ配管の水洗，薬液槽や蓋を給水→満水→排水→給水を繰り返すことで水置換を早く行う水洗等を行う。好ましくは複数回これらの工程を繰り返して薬液処理工程に備える。
【００４３】
実際に上記の薬液処理装置を動作させて薬液洗浄した際の外槽内薬液のｐＨ値（水素イオン濃度値）変化につき実験して得た結果を表２に示す。
【００４４】
【表２】

【００４５】
表２は、強酸性薬液で洗浄処理を始めてから各工程が推移するのに連れて外槽のｐＨ（水素イオン濃度）値の変化を観察したものである。さらに、表２における各工程と、その各々で動作させるべきバルブの番号とを対比して表３として示す。
【００４６】
【表３】

【００４７】
表２，表３によれば、当初のｐＨ値は６．８でおよそ中性であるのに対して途中循環シャワー工程においては、循環液が薬液自身であることもあって一旦ｐＨ値が下がり酸性寄りになるものの、その後純水洗浄の効果を得て、再びｐＨ値が上昇して６．８（中性）を維持している様子が読み取れる。
【００４８】
以上の実施態様では、液封液として純水を採用した場合を例示したが、純水に代えて他の高純度溶液を用いることでも良い。ただし、溶液から実質的に揮発しないか、あるいは揮発する物質が無害でなければならない。
【００４９】
【発明の効果】
本発明によれば、薬液雰囲気が液封液に溶けた後、装置周囲へ飛散して装置周辺雰囲気を汚染してしまう二次汚染の問題さえも避けることができるので、薬液処理時の装置周辺雰囲気の汚染は格段に低減できることとなる。
【図面の簡単な説明】
【図１】 本発明の第一の実施態様に基づく薬液処理装置要部の模式図
【図２】 本発明の第二の実施態様に基づく薬液処理装置要部の模式図
【図３】 本発明の第一の実施態様による薬液処理システムの構成図
【図４】 本発明の第一の実施態様による薬液処理装置の模式図
【図５】 従来の薬液処理装置の模式図
【図６】 従来の改良された薬液処理装置の模式図
【符号の説明】
１，１０，１１，１００......蓋
２，２０，２１......薬液槽
３，２２，３０......外槽
４，４０......中間槽
５０１......液封液給水口
５０２，５１２......液封液排水口
３１......薬液
４１......排気路
４２......排気路
５１......水封水給水路
８１......ドラフト
８２......薬液槽
８３......薬液
８４......排気路
９５......ポンプ
４０１......排気口
１０５......板材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating an object with a chemical solution and a chemical treatment apparatus.
[0002]
[Prior art]
FIG. 5 is a process for manufacturing semiconductor devices and other precision instruments, and has been used for some time in processes such as cleaning semiconductor wafers and parts, for example, by immersing an object in a chemical solution, and in chemical experiments. It is a schematic cross section of a general chemical solution processing tank. In FIG. 5, the chemical solution 83 is stored in the chemical solution tank 82 in the draft 81, but the processing is performed while forcibly exhausting from the exhaust passage 84 in order to suppress diffusion of volatile substances from the chemical solution 83 into the air. . For example, the worker A cleans the object to be cleaned facing the draft 81 by immersing it in the chemical solution 83 using a jig.
[0003]
When such a general chemical treatment tank is used, a problem of volatile substances diffusing from the chemical tank to the periphery has been known for some time. In recent years, parts and devices manufactured in a place close to a chemical processing apparatus are gradually miniaturized, and even if a very small amount of material scatters around the chemical tank, it tends to be overlooked. At the same time, it has been a challenge to further suppress the scattering of volatile substances in the working chamber so that workers engaged in chemical treatment can work more safely.
[0004]
FIG. 6 is a schematic cross-sectional view of a conventional improved chemical processing apparatus. In FIG. 6, the chemical solution 31 is stored in the chemical solution tank 21, and the lid 11 covers the chemical solution tank 21. The atmosphere diffused from the chemical solution is also exhausted from the lid 11 through the exhaust passage 41 to the upper part. At the same time, the atmosphere diffused from the chemical solution 31 is added to the flowing water supplied from the water seal water supply channel 51 to the outer tub 22. An improvement can be seen in that it is melted and poured into the water seal drainage channel 52. In this case, the exhaust from the pure water flowing through the outer tub 22 may be exhausted from the outer tub 22 through the exhaust passage 42 as long as the atmosphere scattered from the pure water cannot be overlooked.
[0005]
[Problems to be solved by the invention]
However, in such a conventional chemical processing apparatus, since the flowing water continues to flow from the water supply channel 51 to the drainage channel 52 while contaminating the outer tub, the problem that the contaminants contained in the flowing water scatter on the contrary cannot be overlooked. Table 1 shows the results obtained by experimenting on the change in the pH value (hydrogen ion concentration value) of the chemical solution in the outer tank when the conventional chemical solution treatment apparatus was actually operated and washed with the chemical solution.
[0006]
[Table 1]

[0007]
Table 1 shows changes in the pH (hydrogen ion concentration) value of the outer tank as each process progresses after the start of the cleaning treatment with the strongly acidic chemical solution, and the initial pH value is about 7.2. Although it is neutral, the pH value continues to decrease gradually and changes from neutral to weakly acidic, and then it can be seen that it is changing to strong acidic, and strongly acidic fine particles scattered from the chemical in the liquid seal solution It can be understood that is adsorbed. As described above, according to the conventional apparatus shown in FIG. 6, the problem that the chemical atmosphere leaks directly around the chemical tank and contaminates the processing chamber is avoided, while the fine particles are scattered in the air from the liquid seal liquid. The problem of causing contamination is very serious, and forced exhausting is required even outside the liquid seal liquid in order to eliminate such air contamination. In other words, after all, even if the apparatus of FIG. 6 is used, if it is tried to prevent air scattering of fine particles in the liquid, a large-capacity exhaust facility must be provided, and the apparatus becomes large. Is not much different from the case of the general conventional apparatus shown in FIG. As described above, even if any of the conventional techniques is used, if a large capacity exhaust facility is not provided in order to avoid the chemical atmosphere of the contamination source used in the cleaning area, the concern about the contamination is still not wiped off and the fine apparatus is processed. However, there is a problem that it is difficult for a worker engaged in the processing to perform the processing safely.
[0008]
The present invention has been made in order to solve the above-described problems of the prior art, prevents contamination from the cleaning area to the outside, maintains the cleanliness of the externally opened liquid sealant, and exhausts a large amount of exhaust air. It is an object of the present invention to reduce and to enable cleaning by spraying a chemical solution or the like that is a contamination source.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention uses, for example, the following configuration.
[0010]
A chemical processing method for cleaning an object such as a semiconductor substrate, a mask / reticle substrate, various glass substrates, etc., which is performed by accumulating a chemical solution in a chemical solution tank, and covering an upper part of the chemical solution tank And an exhaust port was provided immediately above the liquid chemical tank. A lid, and an outer tub configured to receive the supply of pure liquid and to partition the liquid water surface by a partition connected to the lid, and to overflow the liquid through the wall surface toward the inside of the lid from the partition. , Inert gas is introduced from the air inlet provided on the bottom, A method of treating an object with a chemical solution using an intermediate tank that collects the overflowing liquid and guides it to the outside through a drainage channel sufficiently faster than the overflowing. It is preferable that forced exhaust is performed outside the partition in the outer tub.
[0011]
Hereinafter, the above means will be described in more detail with reference to FIGS.
See FIG.
[0012]
FIG. 1 is a schematic diagram of a main part of a chemical processing apparatus according to the first embodiment of the present invention. In the chemical tank in the figure, the chemical liquid used for cleaning the semiconductor substrate is stored, and the upper part of the chemical liquid tank is covered with a lid, so the chemical liquid atmosphere scattered on the upper part of the chemical liquid tank is adjacent to the chemical liquid tank. To the middle tank. On the other hand, the intermediate tank is configured to be adjacent to the outer tank on the outer side, pure water is stored as a liquid seal liquid in the outer tank, and a partition is provided so as to bisect this liquid seal liquid surface, The partition is connected to the lid so that the chemical solution atmosphere does not leak directly to the outside. The liquid seal liquid stored in the outer tank is supplied from the outside of the partition at a constant flow rate, and accordingly, the liquid seal liquid flows along the inner wall surface of the partition and flows down to the intermediate tank. Even if it dissolves in the water, it flows down to the intermediate tank and is drained at a speed much faster than the amount of water supplied, so that the atmosphere around the apparatus is not contaminated.
See FIG.
[0013]
FIG. 2 is a schematic view of a main part of the chemical processing apparatus according to the second embodiment of the present invention. In the apparatus of FIG. 2, in addition to the apparatus of FIG. 1, there is a device for forcibly generating an air flow from the intermediate tank side to the chemical tank so that the exhaust of the chemical atmosphere does not enter the intermediate tank side. It is characteristic that it is given. In the apparatus of FIG. 2, nitrogen is blown from the lower side of the intermediate tank. The reason for selecting nitrogen is that it is inert, but an inert gas such as argon may be used instead of nitrogen. In the exhaust section provided on the chemical tank, the introduced nitrogen gas is exhausted together with the chemical atmosphere, and the intermediate tank is configured to have an exhaust amount that greatly exceeds the amount of nitrogen introduced By preventing the atmosphere in the chemical tank from entering the side, contamination of the liquid fine liquid in the outer tank with the chemical fine particles can be completely avoided.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
See FIG. 1 again.
[0015]
FIG. 1 is a schematic view of a main part of a chemical processing apparatus according to the first embodiment of the present invention, and shows a cross section of the main part of the apparatus. In FIG. 1, a liquid-sealed tank part for liquid-sealing the end of the lid 1 that covers the top of the chemical liquid tank 2 is equipped on the outer periphery of the chemical liquid tank 2. The liquid sealing tank portion is composed of an outer tank 3 and an intermediate tank 4, and the end of the lid 1 is set below the liquid sealing liquid surface stored in the outer tank 3, and the liquid sealing liquid surface is sealed. It is. Although not shown, the outer tank 3 is arranged so as to surround the chemical tank 2, and pure water is always introduced into the outer tank 3 from the liquid sealing liquid supply port 501, and the outer tank 3 is connected to the intermediate tank. 4 overflows along the boundary wall between the two and is collected from the lower surface of the intermediate tank 4 to the liquid seal liquid drain port 502. During this time, when the chemical atmosphere that scatters from the chemical tank 2 touches the liquid sealing liquid surface and is adsorbed in the liquid sealing liquid, it is discharged from the liquid sealing liquid discharge port 502 while being dissolved in the liquid sealing liquid.
See Figure 2.
[0016]
Next, FIG. 2 is a schematic view of the main part of the chemical processing apparatus according to the second embodiment of the present invention, and shows a cross section of the main part of the apparatus. In FIG. 2, the outer periphery of the chemical solution tank 20 is sealed with a liquid seal liquid surface for liquid seal sealing the end of the lid 10 that covers the top of the chemical solution tank 20. Although not shown, the outer tank 30 is disposed so as to surround the chemical tank 20, and pure water is always introduced into the outer tank 30 from the liquid sealing liquid supply port 511 from the outside, and the outer tank 30 is connected to the intermediate tank. 40 overflows along the boundary wall between the two, and is collected from the lower surface of the intermediate tank 40 to the liquid seal liquid drain port 512. During this time, when the chemical liquid atmosphere scattered from the chemical liquid tank 20 touches the liquid sealing liquid surface and is adsorbed in the liquid sealing liquid, it is discharged from the liquid sealing liquid drain port 512 while being dissolved in the liquid sealing liquid. The above points are the same as in the case of the apparatus of FIG. 1, but in addition, in the case of the apparatus of FIG. 2, an exhaust port 401 is provided immediately above the chemical tank 20, and N ₂ A different point is that a purge port is provided at the bottom of the intermediate tank 40 to forcibly generate an exhaust flow. Thus, if it is configured to have an exhaust amount that greatly exceeds the amount of nitrogen introduced, it is possible to forcibly generate an air flow from the intermediate tank side to the chemical tank, and to the intermediate tank side to the chemical tank The contamination of the liquid fine particles in the outer tub can be avoided, and the effect of unintentionally discharging the chemical liquid atmosphere is further enhanced. The reason why nitrogen is selected as the purge gas is only because nitrogen is inactive, and other inert gas such as argon can be used instead.
[0017]
By the way, if the chemical atmosphere is discharged and contamination of the periphery of the apparatus still becomes a problem, it is necessary to thoroughly eliminate all the causes. It is desirable to clean the interior of the apparatus with pure water before and after performing chemical treatment in the chemical bath for such purposes. Such pure water cleaning would be essential for chemical processing such as cleaning of fine devices such as semiconductor devices. Wash the walls of each tank in the chemical tank (“2” in FIG. 1, “20” in FIG. 2) and the intermediate tank (“4” in FIG. 1, “40” in FIG. 2). It is preferable to clean the wall surface of the tank carefully by blowing out pure water from the shower nozzle before and after starting the chemical treatment, respectively. Since contaminated mist may also adhere to the lid (“1” in FIG. 1 and “10” in FIG. 2), if shower nozzle cleaning is performed, pure water is also blown out to the lid. It is good to wash.
See FIG.
[0018]
In order to reduce the contamination due to the chemical atmosphere, it is more effective to make the lid drop into the center of the processing tank. This will be described below with reference to FIG. FIG. 4 is a schematic view of the chemical processing apparatus according to the first embodiment of the present invention, and shows a cross section of the apparatus.
[0019]
In FIG. 4, parts given the same numbers as the part numbers in the other drawings are the same. Since the lid 100 covering the chemical solution tank 2 has a tapered shape, when the lid 100 is washed using a shower nozzle, the blown pure water hits the inner surface of the lid and then follows the taper. The chemical solution tank 2 falls to the center, and after the chemical solution atmosphere melts into the residue remaining on the inner surface of the lid 100, it is also possible to eliminate the contamination by scattering again to the surroundings. The effect of reduction is further increased. In addition, since the lid is tapered, when the chemical bath 2 is filled with water and washed, it is possible to prevent bubbles from being collected just below the lid, and thus the effect of washing with water is also improved on the lid. It can work effectively.
[0020]
Further, the apparatus of FIG. 4 includes a plate member 105 that has a slope from the vicinity of the corner of the lid 100 and has a tip extending toward the intermediate tank 4. This plate material 105 has a function of guiding the liquid droplets that flow down when washing the shower nozzle to fall into the intermediate tank 4 without falling into the outer tank 3, so that the contaminated liquid droplets enter the outer tank 3 and the surroundings. Contributes to reducing the problem of polluting the atmosphere.
As described above, according to the present invention, since the inside of the liquid seal where the chemical atmosphere does not diffuse to the outside is locally exhausted, the exhaust amount can be greatly reduced. Compared to the conventional draft shown in FIG. 5 that does not have a lid, the displacement can be reduced by 85% or more. Compared with the conventional liquid sealing technique shown in FIG. 6, the contamination of the liquid sealing liquid with respect to the treatment with the same acidic chemical solution can be improved to about pH 5 from the conventional pH (hydrogen ion concentration) of about 2. .
See FIG.
[0021]
Next, referring to FIG. 3, the supply / drainage and supply / exhaust systems of the entire chemical treatment system will be described in the order of operation, taking as an example the case where a silicon wafer is immersed in a chemical bath and washed. FIG. 3 is a configuration diagram of the chemical processing system according to the first embodiment of the present invention, in which 91 to 94 and 96 to 914 are valves, 2 is a chemical tank, 3 is an intermediate tank, and 4 is an outer tank. The structure in which the lid 100 covers the chemical tank 2 and the plate material 105 extends from the corner of the lid 100 is the same as that shown in FIG. Before starting the cleaning, first, the valve 91 is opened and pure water is poured into the outer tub 3 as a liquid sealant, and the valve 92 is opened to supply an inert gas such as nitrogen.
[0022]
Before starting the cleaning, first, the valve 91 is opened and pure water is poured into the outer tub as a liquid seal liquid to stabilize the water flow from the bottom to the top, and the valve 92 is opened to supply air and from the outer tub to the chemical tank. Stabilize the airflow to. This air flow prevents the chemical mist from spreading outside the chemical tank. In addition, in order to prevent the mist that could not be prevented from spreading outside the device due to water flow, the valves 91 and 92 will continue to open until the cleaning process is completed.
[0023]
An object to be cleaned such as a jig, a wafer, or a mask substrate is put in a bowl directly attached to the lid 100, and the whole bowl is gradually immersed in the chemical solution. Next, after flowing pure water into the outer tub 3 and confirming that the flow of the liquid seal liquid was stabilized, nitrogen (N ₂ ) Gas is introduced from an air supply port provided at a position just above the intermediate tank 4 on the lid 100 and flows inside the sealed lid 100. Nitrogen (N ₂ ) By introducing gas, the inside of the intermediate tank 4 becomes positive pressure, and the chemical atmosphere can be prevented from flowing from the chemical tank 2 to the intermediate tank 4.
[0024]
Next, with the valves 91 and 92 open, chemical 1 (hydrogen peroxide solution), chemical 2 (ammonia water), chemical 3 (hydrochloric acid aqueous solution), chemical 4 (hydrofluoric acid aqueous solution), chemical 5 (nitric acid aqueous solution) Weigh and open each valve in valve group 3 by the required amount to introduce into chemical tank 2. The preparation of the chemical cleaning solution to be introduced into the chemical bath 2 is performed as follows. In general, high-concentration solutions flow through pipes at various locations in the factory, so they are actually introduced into chemical processing equipment as high-concentration solutions and diluted in the chemical processing equipment. Is simple. However, generally, the higher the concentration of the chemical solution, the higher the volatility of the chemical solution. Therefore, it is more preferable to first introduce pure water into the chemical treatment apparatus and then dilute by introducing the high concentration chemical than the method of diluting after introducing a high concentration chemical into the chemical treatment apparatus. For example, when 10 liters of 10% HF (hydrofluoric acid) solution is prepared, since the concentration of HF (hydrofluoric acid) solution at the time of factory supply is as high as 50%, the volatility is high and the possibility of scattering of the chemical atmosphere increases. Therefore, the pure water for dilution is first stored up to about 4 liters, and then 50% HF (hydrofluoric acid) is added up to about 2 liters. Finally, pure water for stirring is added to about 4 liters to complete the preparation.
[0025]
Specifically, when preparing about 10 liters of 10% HF (hydrofluoric acid) solution in the chemical tank, first, the valve 913 is opened and pure water is introduced to the specified level 1 (about 4 liters supplied). The valve 913 is closed. Subsequently, the valve of the four chemicals in the valve 93 group is opened, 50% HF (hydrofluoric acid) is introduced to the specified level 2 (about 2 liter supply), and then the four chemicals in the valve 93 group are closed. Finally, the valve 913 is opened for stirring and pure water is introduced to a specified level 3 (about 4 liters), and then the valve 913 is closed to complete the preparation.
[0026]
A specified amount of pure water for dilution and stirring is detected by a level sensor. Pure water is suitable for agitation because it can supply a larger flow rate than chemicals. Actually, since the shower is circulated after that, there is no harm even if pure water is not supplied in two portions. Other stirring methods include N ₂ There is also (nitrogen) bubbling, and it is replaced with two-stage dilution with pure water, and the amount of diluted pure water is 8 liters from the beginning. ₂ Bubbling may be performed. N ₂ Other inert gas can be used instead of (nitrogen).
[0027]
Next, after a certain amount of chemicals 1 to 5 are introduced into the chemical tank, all the valve groups 3 are closed.
[0028]
Subsequently, in order to start the circulating shower, the valves 91 and 92 remain open, the valves 96 and 97 and the valve 94 are newly opened, and the pump 95 connected to the valve 94 is operated to discharge from the bottom of the chemical tank 2. The chemical solution (10% HF (hydrofluoric acid) solution) is circulated again through the valves 96 and 97 into the chemical solution tank 2 and sprayed toward the inner wall surface of the chemical solution tank 2. The chemical solution stored in the chemical solution tank 2 is circulated by a pump, and the chemical solution is sprayed from the spray nozzle onto the object to be cleaned to perform the chemical treatment. Such a circulation shower is continued for 5 minutes, and then the same circulation shower is continued for another 10 minutes. Then, the circulation shower is performed for another 15 minutes, followed by the circulation shower for 20 minutes, and then the circulation shower is performed for 25 minutes. After all the series of circulating shower operations are completed, the pump 95 is stopped, the valves 94, 96, 97 are closed, then the valves 98, 99 are opened, and the drains 1 to 3 are used to drain the chemical from the chemical tank 2. To discharge. At this time, drainage is divided into drainage channels 1 to 3; drainage 1 is drainage for hydrofluoric acid, drainage 2 is general acid drainage (chemical solution other than hydrofluoric acid), drainage 3 is pure water recovery (pure water for washing) In order to increase the purity of the wastewater to some extent, it is collected in a recycling facility in the factory and reused as pure water). In addition, when a cleaner chemical treatment is desired by the above circulating shower operation, a filtration filter may be provided between the valve 94 and the pump 95 to circulate the filtered chemical solution.
[0029]
Next, after the valves 98 and 99 are closed and the discharge of the waste water is finished, the valves 91 and 92 are still open, the valve 910 is opened, and the pure water with respect to the back surface of the lid 100 outside the chemical tank 2 is opened. The inside of the lid 100 is washed by taking a shower. A portion of the lid 100 on the intermediate tank 4 and the outer tank 3 is washed with water.
[0030]
Next, the valve 910 is closed, then the valve 911 is opened, and the inside of the lid 100 is washed by taking a shower of pure water against the back side of the lid 100 inside the chemical tank 2. The lid 100 on the portion above the chemical tank 2 is washed with water.
[0031]
After closing the valve 911, with the valves 91 and 92 still open, the valves 96, 97 and 912 are opened, and pure water is shower-injected onto the inner wall surface of the chemical tank 2. In addition to washing the inside of the chemical tank 2 and the shower nozzle part, the object to be washed is also washed incompletely. For example, in the case of an HF (hydrofluoric acid) solution, the surface of the object to be cleaned becomes rough if it is left as it is attached to the chemical solution, so that the nozzle is temporarily cleaned to avoid it. Also, since the pipes are shared with each chemical solution, if different chemical solutions are mixed and not washed with water for each chemical reaction mixture, the previous mixture solution (for example, HF (hydrofluoric acid) solution) and the next mixture solution (excessive solution) Hydrogen oxide + ammonia solution) will mix and cause a chemical reaction.
[0032]
After all the valves 96, 97, 912 are closed and the work shower operation is finished, pure water is shower sprayed again toward the inside of the lid 100 outside the chemical solution tank 2 to clean the inside of the lid 100. Subsequently, the valve 910 is closed, the valves 91 and 92 are kept open, the valve 911 is newly opened, and pure water is shower-injected toward the inside of the lid 100 inside the chemical solution tank 2 to wash the inside of the lid 100. . Next, the valve 912 is closed to finish the cleaning of the lid 100, and the work shower is performed again. While the valves 91 and 92 are kept open, the valves 96, 97 and 912 are opened. This is because the chemical piping and the shower cleaning circulation pump piping are washed with water.
[0033]
The liquid (water + HF (hydrofluoric acid)) in the chemical tank 2 is drained.
[0034]
The object to be cleaned and the chemical tank 2 are washed with water. Depending on the shape of the object to be cleaned, the liquid may accumulate or the chemical solution may remain in the groove. If only the shower cleaning is performed, the chemical solution may not be completely washed (water replacement). By doing so, complete water replacement can be performed. In addition, since the chemical tank 2 is made of PVC (vinyl chloride), the chemical liquid tends to remain between the PVC molecules when the chemical liquid is touched for a long time, and pure water is stored in the chemical tank 2 rather than shower cleaning. The water washing effect can be improved more effectively. However, even with a method of storing pure water in the chemical tank 2, it is difficult to completely remove the chemical liquid that has entered between the PVC molecules. Therefore, in order to completely eliminate the cause of contamination by the chemical atmosphere, the chemical tank 2 It is best not to employ PVC as the material of the material. It has been found that if two-stage washing of warm water and room temperature water is adopted, the effect of washing the chemical tank 2 itself is enhanced compared to the case of washing with room temperature water alone. If it is used as, it is desirable to employ warm water washing + room temperature water washing.
[0035]
Next, the chemical tank 2 is filled with water. The object to be cleaned and the chemical tank 2 are also washed with water. However, since the chemical liquid splashed in the shower may adhere to the lid 100, the object is to wash the lid 100 on the upper part of the chemical tank 2 with water. This is also because the washing effect is higher when immersed in the shower (because there is only a slight gap between the chemical tank 2 and the pure water overflows from the chemical tank 2 so that the entire surface of the lid 100 is immersed in water). .
[0036]
The drainage of the liquid is started from the chemical tank 2. Since it is almost pure water level, the wastewater is recovered with pure water (drainage 3).
[0037]
Next, drying of the chemical tank 2 is started. The object to be cleaned is naturally dried while the inside of the chemical tank 2 is clean. The valve 91 is opened to introduce pure water as a liquid seal liquid, but since the purpose is only to shut off from the outside by the liquid seal, it is understood that the pH (hydrogen ion concentration) value is close to 7.0. When it is clear that the purity of the liquid is in the state of pure water, it is not necessary to newly open the valve 91 and flow in pure water. In this case, the valve 91 need not be opened. If the liquid seal liquid seems to be contaminated, the valve 91 is opened and fresh water is poured. N ₂ By flowing (nitrogen) inside the sealed lid 100 and making the inside of the chemical tank 2 positive pressure, it is possible to prevent the chemical atmosphere from flowing from the drain pipe and exhaust to the chemical tank 2. Next, the valves 98 and 99 are opened to drain the chemical tank 2. Since it is almost pure water level, the wastewater is recovered with pure water (drainage 3).
[0038]
Next, pull up the bag containing the workpiece. After fully pulling up to the lid 100 side, the lid 100 is opened and the object to be processed in the basket is taken out. At this time, pure water as a liquid sealing liquid may be introduced by opening the valve 91. As in the previous step, when it has been confirmed that the pH of the liquid sealing liquid has changed and the purity of the liquid sealing liquid has been lowered, the valve 91 is thus opened to introduce pure water. There is a meaning. Valve 92 is N ₂ Flow (nitrogen) gas inside the sealed lid. The flowing gas is N ₂ Instead of (nitrogen), another inert gas such as argon may be used. Thus, opening the valve 91 and flowing an inert gas prevents the chemical gas from flowing backward from the drain pipe or the exhaust to the chemical liquid tank by making the inside of the chemical liquid tank a positive pressure, and covers the lid. There is an effect that the opening operation can be performed smoothly.
[0039]
In the above description of the embodiment of the present invention, the shower cleaning of the outer tub lid, the shower cleaning of the inner tub lid, and the work shower are performed separately. The reason is as follows.
Reason 1)
If pure water is discharged from three showers at the same time, the flow rate of pure water from each shower drops, and as a result, pure water does not cover the entire surface of the lid or chemical bath, and does not cover the entire area to be cleaned. This is because there may be a problem that.
Reason 2)
When the lid is washed with overflow water in the 23rd overflow (soak the lid in water), a gentle taper like the bottom of the ship is applied to all sides to prevent bubbles from sticking to the surface of the lid. ing. However, the eleventh inner tub lid shower has a strong momentum (the entire surface of the large lid cannot be washed unless it is strong), so shower water (pure water + chemical) flows from the inner tub toward the outer tub against the taper. It may lead to contamination of water seal water. Therefore, first, pure water is poured from the outer tub toward the treatment tank in the outer tub shower to wash away the chemical solution attached to the lid as much as possible in the chemical tub. After that, it is desirable to perform inner tank lid shower + work shower (water washing of the chemical tank). There is no problem if the inner tub shower and the work shower are performed simultaneously after the outer tub shower, and the contamination can be further reduced by flowing three showers simultaneously.
[0040]
The cleaning operation is repeated for the following reason.
[0041]
Since each part of each shower water wash is separately washed with three showers, repeated washing results in less water washing unevenness.
[0042]
In addition to the above, before and after the chemical treatment process, flushing of the walls of the chemical tank, flushing of the liquid supply pipe and circulation pump pipe, water washing that quickly replaces the water by repeating the water supply, full water, drainage, and water supply of the chemical tank and lid Etc. Preferably, these steps are repeated a plurality of times to prepare for the chemical treatment process.
[0043]
Table 2 shows the results obtained by experimenting on the change in pH value (hydrogen ion concentration value) of the chemical solution in the outer tank when the chemical solution treatment apparatus was actually operated and the chemical solution was washed.
[0044]
[Table 2]

[0045]
Table 2 shows changes in the pH (hydrogen ion concentration) value of the outer tank as each process progresses after the cleaning treatment with the strongly acidic chemical solution is started. Further, Table 3 compares each step in Table 2 with the number of the valve to be operated in each step.
[0046]
[Table 3]

[0047]
According to Tables 2 and 3, the initial pH value is 6.8, which is about neutral, whereas in the circulating shower process, the circulating liquid is the chemical solution itself, so the pH value once decreases. Although it becomes closer to acidity, it can be seen that the effect of pure water washing is obtained, and the pH value rises again to maintain 6.8 (neutral).
[0048]
Although the case where pure water was employ | adopted as a liquid sealing liquid was illustrated in the above embodiment, it may replace with pure water and may use another high purity solution. However, the material must not substantially volatilize or the material that volatilizes must be harmless.
[0049]
【The invention's effect】
According to the present invention, since the chemical atmosphere is dissolved in the liquid seal liquid, it is possible to avoid even the problem of secondary contamination that scatters around the apparatus and contaminates the atmosphere around the apparatus. Atmospheric contamination can be significantly reduced.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a main part of a chemical processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic diagram of a main part of a chemical processing apparatus according to a second embodiment of the present invention.
FIG. 3 is a block diagram of a chemical processing system according to the first embodiment of the present invention.
FIG. 4 is a schematic view of a chemical processing apparatus according to the first embodiment of the present invention.
FIG. 5 is a schematic diagram of a conventional chemical processing apparatus.
FIG. 6 is a schematic diagram of a conventional improved chemical processing apparatus.
[Explanation of symbols]
1,10,11,100 ...... lid
2,20,21 ...... chemical tank
3, 22, 30 ...... Outer tank
4,40 ...... Intermediate tank
501: Liquid seal water supply port
502, 512 ...... Sealing liquid drain port
31 ...... Chemical solution
41 ...... Exhaust passage
42 ...... Exhaust passage
51 ...... Water-sealed water supply channel
81. Draft
82 ...... chemical tank
83 ...... Chemical solution
84 ...... Exhaust passage
95 ...... Pump
401 ...... Exhaust port
105 ...... Plate material

Claims (4)

A method for treating an object by storing a chemical in a chemical tank,
Have covered the top of the drug solution tank, and a lid outlet is provided directly above the liquid chemical bath, supplied with pure liquid, liquid water is divided by a partition that led to the lid, than the partition An outer tank configured to overflow the liquid along the wall surface toward the inside of the lid, and an inert gas is introduced from the intake port provided at the bottom, and the overflowed liquid is recovered, A method of treating an object with a chemical solution using an intermediate tank that leads to the outside through a drainage channel sufficiently earlier than the overflow. The inert gas introduced from the intake port and the chemical atmosphere from the chemical tank are exhausted from the exhaust port,
The exhaust amount from the exhaust port is larger than the introduction amount of the inert gas from the intake port to such an extent that the chemical solution atmosphere does not enter the intermediate side. A method of treating the object according to the chemical solution. A chemical tank for storing chemicals and processing objects,
Have covered the top of the drug solution tank, and a lid outlet is provided directly above the liquid chemical bath,
An outer tub configured to flow the pure liquid, the liquid water surface is divided by a partition connected to the lid, and the liquid overflows along the wall surface toward the inside of the lid from the partition;
A chemical processing apparatus having an intermediate tank that introduces an inert gas from an intake port provided at the bottom, collects the overflowed liquid, and guides the liquid to the outside through the drainage channel sufficiently faster than the overflow. The inert gas introduced from the intake port and the chemical atmosphere from the chemical tank are exhausted from the exhaust port,
The exhaust amount from the exhaust port is larger than the introduction amount of the inert gas from the intake port to such an extent that the chemical atmosphere does not enter the intermediate side.
The chemical | medical solution processing apparatus of Claim 3 characterized by the above-mentioned.

Images