JP4195831B2

JP4195831B2 - How to detect harmful gases

Info

Publication number: JP4195831B2
Application number: JP2003152146A
Authority: JP
Inventors: 孝島田; 常勝米山; 幸平佐々木
Original assignee: Japan Pionics Ltd
Current assignee: Japan Pionics Ltd
Priority date: 2003-05-29
Filing date: 2003-05-29
Publication date: 2008-12-17
Anticipated expiration: 2023-05-29
Also published as: JP2004354194A

Description

【０００１】
【発明の属する技術分野】
本発明は有害ガスの検知方法に関する。さらに詳細には、半導体製造工程等から排出される有害ガスを、浄化筒に充填された浄化剤と接触させることにより浄化するとともに、浄化剤の充填部を通過するガスに含まれる有害ガス成分を検知する方法に関する。
【０００２】
【従来の技術】
半導体製造工業においては各種のガスが使用されており、水素化物ガスとしては、アルシン、ホスフィン、シラン、ジボラン、セレン化水素等が、酸性ガスとしては、フッ素、塩素、フッ化水素、塩化水素、三フッ化塩素、三フッ化ホウ素、三塩化ホウ素、四フッ化珪素、四塩化珪素、四塩化チタン、塩化アルミニウム、四フッ化ゲルマニウム、六フッ化タングステン等が、塩基性ガスとしては、アンモニア、モノメチルアミン、ジメチルアミン、トリメチルアミン、ヒドラジン等が多量に使用されている。これらのガスは毒性を有するため、半導体製造工程等で使用された後、これらの有害ガス成分を含む排ガスは大気中に放出するに先立って浄化する必要がある。
【０００３】
従来より、前記の有害ガスの浄化方法としては、浄化剤を浄化筒に充填し、有害ガスを浄化筒に導入して、有害ガス成分を浄化剤と接触させて捕捉することにより浄化する乾式浄化方法が多く実施されてきた。乾式浄化方法において、各種の浄化剤は、各々有害ガス成分に対する固有の浄化能力（浄化剤単位量当りの有害ガス成分処理量）を有しており、ある程度の量の有害ガス成分を捕捉できるが、それを超えると捕捉できなくなり、有害ガス成分を下流側へ流してしまう虞があった。そのため、例えば浄化剤の充填部のうち比較的下流側の位置に浄化筒の外側から浄化筒内を観察することができる覗窓を設け、これに有害ガス成分と接触して変色する検知剤を充填して、浄化剤層が破過する直前で有害ガス成分を検知することが行なわれている。
【０００４】
【発明が解決しようとする課題】
乾式浄化方法においては、有害ガスが浄化剤と接触する際に、有害ガス成分と浄化剤が化学反応を起こすか、あるいは有害ガス成分が浄化剤に吸着されて、有害ガス成分が浄化剤に捕捉される。このような有害ガス成分の反応部または吸着部は、浄化剤層の上流側から徐々に下流側に進行する。しかしながら、浄化剤層の中心部と周辺部の位置の違い、有害ガスに含まれる粉化物の浄化剤層における堆積状態等により、有害ガス成分の反応部または吸着部は、通常は浄化剤層を均一に進行しない。特に浄化筒の径が大きい場合はこの傾向が顕著になり、覗窓の検知剤が変色していないにもかかわらず有害ガス成分が浄化筒の下流側へ流れる虞があった。
【０００５】
このため、有害ガス成分の反応部または吸着部の進行状態を正確に検知する方法として、例えば検知剤が充填された覗窓を複数個所に設置することが検討された。しかしながら、この方法では浄化剤の有害ガスとの反応、あるいは浄化剤による有害ガスの吸着が浄化筒の中心部で早く進行した場合は浄化筒の破過を見逃す虞があった。また、浄化剤の充填部を二分割し、浄化剤の充填部間に空間を設け、その空間部に検知剤が充填された覗窓を設けることも考えられたが、空間内における浄化筒半径方向のガスの拡散では、有害ガス成分の濃度が数ｐｐｍと低い場合は検知剤の変色が遅くなり、前記の方法と同様に有害ガス成分の捕捉部が浄化筒の中心部で早く進行した場合は浄化筒の破過を見逃す虞があった。
【０００６】
従って、本発明が解決しようとする課題は、半導体製造工程等から排出される有害ガスを、浄化筒に充填された浄化剤と接触させることにより浄化するとともに、浄化剤の充填部を通過するガスに含まれる有害ガス成分を検知する方法において、浄化剤の有害ガス成分との反応部、あるいは浄化剤による有害ガス成分の吸着部の進行状態を正確に検知することが可能な有害ガスの検知方法を提供することである。
【０００７】
【課題を解決するための手段】
本発明者らは、これらの課題を解決すべく鋭意検討した結果、前記のような有害ガス成分の検知において、浄化剤の充填部の少なくとも一部に空隙部を設け、この空隙部を有害ガス成分の検知部と連通させて空隙部から流通するガスを分析することにより、浄化剤の有害ガス成分との反応部、あるいは浄化剤による有害ガス成分の吸着部の進行状態を正確に検知できることを見い出し、本発明の有害ガスの検知方法に到達した。
【０００８】
すなわち本発明は、有害ガスを浄化筒に導入し、浄化筒に充填された浄化剤と接触させることにより有害ガスを浄化するとともに、浄化剤の充填部を通過する有害ガス成分を検知する方法であって、該浄化剤の充填部の少なくとも一部に有害ガス成分の検知部と連通する空隙部を設け、該連通部は該検知部と隣接する端部が該検知部のガス流の上流面または側面に隣接するように設定し、該空隙部から流通するガスに含まれる有害ガス成分を該検知部により検知することを特徴とする有害ガスの検知方法である。
【０００９】
【発明の実施の形態】
本発明は、半導体製造工程等から排出される有害ガスを浄化筒に導入し、浄化筒に充填された浄化剤と接触させることにより有害ガスを浄化するとともに、浄化剤の充填部を通過する有害ガス成分を検知する方法に適用される。
本発明の有害ガスの検知方法は、浄化剤の充填部の少なくとも一部に有害ガス成分の検知部と連通する空隙部を設け、前記空隙部から流通するガスに含まれる有害ガス成分を検知部により検知する方法である。
【００１０】
本発明における有害ガス成分は、半導体製造工程等から排出され、乾式浄化方法により浄化され得るものであれば特に制限されることがない。これらの有害ガス成分としては、例えば、アルシン、ホスフィン、シラン、ジボラン、セレン化水素等の水素化物ガス、フッ素、塩素、フッ化水素、塩化水素、三フッ化塩素、三フッ化ホウ素、三塩化ホウ素、四フッ化珪素、四塩化珪素、四塩化チタン、塩化アルミニウム、四フッ化ゲルマニウム、六フッ化タングステン等の酸性ガス、アンモニア、モノメチルアミン、ジメチルアミン、トリメチルアミン、ヒドラジン等の塩基性ガスを挙げることができる。これらは、通常は、窒素、水素、アルゴン、ヘリウム等のベースガスに含有された状態で排出される。
【００１１】
本発明における浄化剤は、前記有害ガス成分を含有する有害ガスを、乾式浄化方法により浄化できるものであれば特に制限されることがない。これらの浄化剤としては、例えば、二酸化マンガン及び酸化銅を主成分とする水素化物ガスの浄化剤、活性炭に蟻酸のアルカリ金属塩及び／または蟻酸のアルカリ土類金属塩を添着させたハロゲン系ガスの浄化剤、二酸化マンガン及び酸化銅を主成分とする組成物に銅塩を添着させた塩基性ガスの浄化剤等を挙げることができる。また、前記有害ガス成分との組み合せで、粉化物を生成するものであってもよい。
【００１２】
本発明における検知剤は、前記有害ガス成分を検知できるものであれば特に制限されることがない。これらの検知剤としては、例えば、無機質担体に変色成分としてモリブデン酸塩を担持させた水素化物ガスの検知剤、塩基性炭酸銅を変色成分とする水素化物ガスの検知剤、遷移金属の水酸化物とコンゴーレッドを変色成分とする酸性ガスの検知剤等を挙げることができる。また、本発明における検知部としては、浄化筒の外側から浄化筒内を観察することができる覗窓を設け、これに前記の検知剤を充填した検知部のほか、浄化筒に設けられたガス取入口と浄化筒の外部に設けられた有害ガス成分の検知手段からなる検知部も用いることが可能である。
【００１３】
以下、本発明の有害ガスの検知方法を図１〜図６に基いて説明するが、本発明がこれらにより限定されるものではない。
図１、図２は、本発明の検知方法が実施可能な浄化筒の鉛直方向の構成例を示す断面図である。図３、図４は、本発明の検知方法が実施可能な浄化筒の浄化剤層中に設けられる空隙部、連通部、及び検知部の鉛直方向の構成例を示す断面図である。図５は、本発明の検知方法が実施可能な浄化筒の空隙部、連通部、及び検知部における水平方向の構成例を示す断面図である。図６は、本発明の検知方法において、浄化剤の充填部に空隙部及び連通部を設けるための手段（内部が空洞である容器）の例を示す斜視図である。
【００１４】
本発明の検知方法を実施するために用いられる浄化筒は、図１、図２に示すように、有害ガスの導入口１、浄化剤の充填部２、浄化されたガスの排出口３、及び検知部４のほか、浄化剤の充填部の少なくとも一部に空隙部５、及びこれと検知部を連通する連通部６が設けられる。これらの空隙部と連通部は、空隙部に導入されたガスが、容易に連通部を流通し、検知部に到達するような構成とされる。本発明の検知方法においては、浄化剤の充填部に、空隙部及び連通部を設けるために、通常は図６に示すような内部が空洞である容器が使用される。このような容器を用いた場合を含めて、浄化剤の充填部に設けられる空隙部及び連通部は次のような構成とされる。
【００１５】
即ち、空隙部５は、図３、図４に示すように、ガス流７の上流面８（ダウンフローの場合は上面、アップフローの場合は下面）がガス透過性材料で構成され、ガス流７の下流面９（ダウンフローの場合は下面、アップフローの場合は上面）及び側面１０は、好ましくはガス非透過性材料で構成される。（図３、図４に示す空隙部及び連通部において、点線はガス透過性材料の面、実線はガス非透過性材料の面であることを示すものである。）このような構成とすることにより、浄化剤層を通過したガスが、空隙部に導入されやすくなるとともに、一旦導入されたガスが下流面から逃げにくくなる。
【００１６】
連通部６は、ガス流７の上流面８’については、図３（１）（３）（４）（５）（６）、または図４（１）（３）（４）（５）（６）に示すようにガス透過性材料であってもよいし、図３（２）、図４（２）に示すようにガス非透過性材料であってもよいが、検知部と隣接する端部面１１はガス透過性材料で構成される。また、連通部の下流面のうち検知部と隣接しない面、及び側面のうち検知部と隣接しない面は、好ましくはガス非透過性材料で構成される。このような構成とすることにより、空隙部または連通部の上流面から導入されたガスが、検知部に流通されやすくなる。
【００１７】
空隙部及び連通部に使用されるガス透過性材料としては、有害ガス成分に対する耐腐食性を備え、浄化剤の侵入を防止することができるものであれば特に制限されることがないが、例えば網状の炭素鋼、マンガン鋼、クロム鋼、モリブデン鋼、ステンレス鋼等を使用することができる。また、ガス非透過性材料としては、有害ガス成分に対する耐腐食性を備えたものであれば特に制限されることがないが、通常は板状の炭素鋼、マンガン鋼、クロム鋼、モリブデン鋼、ステンレス鋼等を使用することができる。
【００１８】
本発明において、前述のような連通部は、例えば、その検知部と隣接する端部面１１が、図３（１）〜（３）、図４（１）〜（３）に示すように、検知剤のガス流の上流面に隣接するように設定されるか、または図３（４）、図４（４）に示すように検知剤の側面に隣接するように設定される。また、検知部と隣接する端部面１１は、図３（５）（６）、図４（５）（６）に示すように、必ずしも検知剤１２と接触していなくてもよいが、検知部と隣接する端部面と検知剤の距離は、５ｃｍ以内に設定することが好ましい。
【００１９】
本発明において、空隙部及び連通部は、その大きさ、形状に特に制限されることがない。しかし、空隙部及び連通部の内部を合せた容積は、通常は浄化剤の充填部の０．１〜１０％、好ましくは０．２〜５％の容積である。空隙部、連通部の外形は、立方体、直方体、球、楕球、円錐、円錐台、角錐、角錐台、環、これらに類似する形状、これらを組合せた形状等とすることができる。また、これらの水平方向の配置については、図５に示すようなものを例示することができる。空隙部及び連通部の上流面に設定されるガス透過性材料の構成部（ガス導入部）は、水平方向の合計の断面積で、通常は浄化剤の充填部の１〜４０％、好ましくは５〜３０％の断面積である。
【００２０】
本発明の検知方法を実施するに際しては、浄化筒は以上のような構成にセットされる。尚、本発明において、浄化筒に充填される浄化剤の充填長は、実用上通常は１０〜２００ｃｍとされる。浄化筒を流通する有害ガスの流通速度は、特に制限はないが、通常は空筒線速度で０．１〜５０ｃｍ／ｓｅｃ程度である。また、温度、圧力にも特に制限はなく、温度は通常は−２０〜３００℃、圧力は通常は常圧であるが、１ｋＰａ（ａｂｓ）の減圧から１ＭＰａ（ａｂｓ）の加圧下においても実施可能である。
【００２１】
【実施例】
次に、本発明を実施例により具体的に説明するが、本発明がこれらにより限定されるものではない。
【００２２】
実施例１
（浄化筒の設定）
空隙部及び連通部として、ガス流の上流面側となる面及び検知部と隣接する端部となる面が網状のステンレス鋼、その他の面が板状のステンレス鋼からなる図６に示すような容器を製作した。この容器は浄化筒に図５（２）のような配置で設置されるものである。空隙部及び連通部を合せた長辺は３５０ｍｍ、検知部と隣接する端部面は、横３０ｍｍ、高さ１０ｍｍである。
【００２３】
次に、二酸化マンガン、酸化銅を主成分とする市販のホプカライト（日産ガードラー（株）製、直径１．５ｍｍ、長さ３〜１０ｍｍの押し出し成型品）１００重量部に対して、水酸化カリウムを３０重量部担持させて浄化剤を調製した。また、比表面積３００ｍ^２／ｇの粒状シリカゲル（富士シリシア化学（株）製、キャリアクト−１０）１００ｇに、変色成分として燐モリブデン酸水和物１．０ｇ及び硫酸第二銅５水和物０．２ｇを水２７０ｍＬに溶解した溶液を含浸させた後、７５℃で乾燥させて検知剤を調製した。
【００２４】
内径４００ｍｍのステンレス鋼製の浄化筒に、厚さ８０ｍｍとなるように前記の浄化剤を充填するとともに、浄化筒の周辺部４箇所に互いの距離が均等となるように設けられた覗窓部に前記の検知剤を充填した。検知剤はその上面が浄化剤の上面と同一の高さになるように設定した。
次に前記の容器を、４箇所の端部面が各々４箇所の検知部に隣接するように浄化剤の上面に配置し、さらに全体の充填長が４００ｍｍとなるように前記の浄化剤を追加充填した。
【００２５】
（検知試験）
乾燥窒素中にＳｉＨ_４を５０００ｐｐｍ含む有害ガスを、常圧、２５℃、流量２００Ｌ／ｍｉｎの条件下、ダウンフローで前述の浄化筒に導入し、検知剤が変色し始めるまでの時間を測定した。また、浄化筒の出口ガスの一部をサンプリングして、ＳｉＨ_４が検知されるまでの時間（浄化剤の破過時間）を測定した。これらの結果を表１に示す。また、浄化剤の充填長と検知剤の位置を考慮して、浄化剤の破過時間から計算した検知剤の変色開始時間を併せて示す。
【００２６】
比較例１
空隙部及び連通部を配置しなかった以外は実施例１と同様の浄化剤及び検知剤を用いて、実施例１と同様にして浄化筒の設定を行なった。
実施例１と同様の条件下でＳｉＨ_４を浄化筒に導入し、検知剤が変色し始めるまでの時間、浄化剤の破過時間を測定した。これらの結果を表１に示す。また、浄化剤の充填長と検知剤の位置を考慮して、浄化剤の破過時間から計算した検知剤の変色開始時間を併せて示す。
【００２７】
【表１】

【００２８】
【発明の効果】
本発明の有害ガスの検知方法により、半導体製造工程等から排出される有害ガスを、浄化筒に充填された浄化剤と接触させることにより浄化する際に、浄化剤の有害ガス成分との反応部、あるいは浄化剤による有害ガス成分の吸着部の進行状態を正確に検知することが可能となった。
【図面の簡単な説明】
【図１】本発明の検知方法が実施可能な浄化筒の鉛直方向の構成例を示す断面図
【図２】本発明の検知方法が実施可能な図１以外の浄化筒の鉛直方向の構成例を示す断面図
【図３】本発明の検知方法が実施可能な浄化筒の浄化剤層中に設けられる空隙部、連通部、及び検知部の鉛直方向の構成例を示す断面図（ダウンフローの場合）
【図４】本発明の検知方法が実施可能な浄化筒の浄化剤層中に設けられる空隙部、連通部、及び検知部の鉛直方向の構成例を示す断面図（アップフローの場合）
【図５】本発明の検知方法が実施可能な浄化筒の空隙部、連通部、及び検知部における水平方向の構成例を示す断面図
【図６】浄化剤の充填部に空隙部及び連通部を設けるための手段の例を示す斜視図
【符号の説明】
１有害ガスの導入口
２浄化剤の充填部
３浄化されたガスの排出口
４検知部（検知剤と覗窓を含む構成）
５空隙部
６連通部
７ガス流
８空隙部の上流面
８’ 連通部の上流面
９空隙部の下流面
９’ 連通部の下流面
１０空隙部または連通部の側面
１１連通部の検知部と隣接する端部面
１２検知剤[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for detecting harmful gases. More specifically, the harmful gas discharged from the semiconductor manufacturing process or the like is purified by bringing it into contact with the purification agent filled in the purification cylinder, and harmful gas components contained in the gas passing through the filling portion of the purification agent are removed. It relates to the detection method.
[0002]
[Prior art]
Various gases are used in the semiconductor manufacturing industry. As hydride gases, arsine, phosphine, silane, diborane, hydrogen selenide, etc. are used. As acid gases, fluorine, chlorine, hydrogen fluoride, hydrogen chloride, Chlorine trifluoride, boron trifluoride, boron trichloride, silicon tetrafluoride, silicon tetrachloride, titanium tetrachloride, aluminum chloride, germanium tetrafluoride, tungsten hexafluoride, etc. are basic gases such as ammonia, Monomethylamine, dimethylamine, trimethylamine, hydrazine and the like are used in large quantities. Since these gases are toxic, exhaust gases containing these harmful gas components must be purified before they are released into the atmosphere after being used in a semiconductor manufacturing process or the like.
[0003]
Conventionally, as a method for purifying the harmful gas, the dry purification is performed by filling the purifier with the purifier, introducing the harmful gas into the purifier, and capturing the harmful gas components in contact with the purifier. Many methods have been implemented. In the dry purification method, each of the various purification agents has a specific purification capacity for harmful gas components (hazardous gas component processing amount per unit amount of the purification agent), and can capture a certain amount of harmful gas components. If it exceeds that, it could not be captured, and harmful gas components could flow downstream. For this reason, for example, a viewing window that can observe the inside of the purification cylinder from the outside of the purification cylinder is provided at a relatively downstream position in the purification agent filling portion, and a detection agent that changes color in contact with harmful gas components is provided on this. Filling and detecting harmful gas components immediately before the purifier layer breaks through.
[0004]
[Problems to be solved by the invention]
In the dry purification method, when harmful gas comes into contact with the cleaning agent, the harmful gas component and the cleaning agent cause a chemical reaction, or the harmful gas component is adsorbed by the cleaning agent, and the harmful gas component is captured by the cleaning agent. Is done. Such a reaction part or adsorption part of the harmful gas component gradually proceeds downstream from the upstream side of the purifier layer. However, due to the difference in position between the central part and the peripheral part of the purifier layer, the accumulation state of the pulverized material contained in the harmful gas in the purifier layer, etc. It does not progress uniformly. In particular, when the diameter of the purification cylinder is large, this tendency becomes remarkable, and there is a possibility that harmful gas components may flow to the downstream side of the purification cylinder even though the detection agent of the observation window is not discolored.
[0005]
For this reason, as a method for accurately detecting the progressing state of the reaction part or the adsorption part of the harmful gas component, for example, it has been considered to install a plurality of observation windows filled with a detection agent. However, in this method, when the reaction of the purifying agent with the harmful gas or the adsorption of the harmful gas by the purifying agent proceeds quickly in the center of the purifying tube, there is a possibility that the breakthrough of the purifying tube may be missed. It was also considered that the purifying agent filling part was divided into two parts, a space was provided between the purifying agent filling parts, and a viewing window filled with the detection agent was provided in the space part. In the direction of gas diffusion, when the concentration of harmful gas components is as low as a few ppm, discoloration of the detection agent is delayed, and in the same way as in the above method, the trapping portion of the harmful gas components proceeds quickly at the center of the purification cylinder. Could overlook the spill tube.
[0006]
Accordingly, the problem to be solved by the present invention is to purify the harmful gas discharged from the semiconductor manufacturing process etc. by bringing it into contact with the purifying agent filled in the purifying cylinder and to pass through the purifier filling portion. Method for detecting harmful gas components contained in the gas, which can accurately detect the progress of the reaction part of the purifier with the harmful gas component or the adsorbing part of the harmful gas component by the purifier Is to provide.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve these problems, the present inventors have provided a void in at least a part of the purifier filling portion in the detection of the harmful gas component as described above, and the void is defined as a harmful gas. It is possible to accurately detect the progress of the reaction part with the harmful gas component of the purifier or the adsorbing part of the harmful gas component by the purifier by analyzing the gas flowing from the gap part in communication with the component detection part. As a result, the method for detecting harmful gases according to the present invention has been reached.
[0008]
That is, the present invention is a method for purifying harmful gas by introducing harmful gas into a purification cylinder and bringing it into contact with a purification agent filled in the purification cylinder, and detecting a harmful gas component passing through a purifier filling portion. A gap portion communicating with the detection unit for harmful gas components is provided in at least a part of the purifying agent filling portion, and the end portion adjacent to the detection unit is an upstream surface of the gas flow of the detection unit. Or it is set so that it may adjoin to a side surface, It is the detection method of the noxious gas characterized by detecting the noxious gas component contained in the gas which distribute | circulates from this space | gap part by this detection part.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention introduces harmful gas discharged from a semiconductor manufacturing process, etc. into a purification cylinder, purifies the harmful gas by bringing it into contact with the purification agent filled in the purification cylinder, and also passes through the filling part of the purification agent. It is applied to a method for detecting a gas component.
The harmful gas detection method of the present invention is provided with a void portion communicating with a harmful gas component detection portion in at least a part of a purifier filling portion, and detects a harmful gas component contained in a gas flowing from the void portion. It is the method of detecting by.
[0010]
The harmful gas component in the present invention is not particularly limited as long as it is discharged from a semiconductor manufacturing process or the like and can be purified by a dry purification method. Examples of these harmful gas components include hydride gases such as arsine, phosphine, silane, diborane, hydrogen selenide, fluorine, chlorine, hydrogen fluoride, hydrogen chloride, chlorine trifluoride, boron trifluoride, trichloride. Examples include acidic gases such as boron, silicon tetrafluoride, silicon tetrachloride, titanium tetrachloride, aluminum chloride, germanium tetrafluoride, tungsten hexafluoride, and basic gases such as ammonia, monomethylamine, dimethylamine, trimethylamine, and hydrazine. be able to. These are usually discharged in a state in which they are contained in a base gas such as nitrogen, hydrogen, argon, or helium.
[0011]
The purification agent in the present invention is not particularly limited as long as the harmful gas containing the harmful gas component can be purified by a dry purification method. Examples of these purifiers include hydride gas purifiers mainly composed of manganese dioxide and copper oxide, and halogen-based gases obtained by impregnating activated carbon with an alkali metal salt of formic acid and / or an alkaline earth metal salt of formic acid. And a purifying agent for basic gas in which a copper salt is impregnated with a composition mainly composed of manganese dioxide and copper oxide. Moreover, a powdered product may be generated in combination with the harmful gas component.
[0012]
The detection agent in the present invention is not particularly limited as long as it can detect the harmful gas component. These detection agents include, for example, hydride gas detection agents in which molybdate is supported as a discoloring component on an inorganic carrier, hydride gas detection agents having basic copper carbonate as a discoloration component, and transition metal hydroxides. Examples include acid gas detectors that use a product and Congo red as a color-changing component. Moreover, as a detection part in this invention, the observation window which can observe the inside of a purification | cleaning cylinder from the outer side of a purification | cleaning cylinder is provided, and the gas provided in the purification cylinder other than the detection part filled with the said detection agent in this is provided. It is also possible to use a detection unit comprising detection means for harmful gas components provided outside the intake and the purification cylinder.
[0013]
Hereinafter, although the detection method of the noxious gas of this invention is demonstrated based on FIGS. 1-6, this invention is not limited by these.
1 and 2 are cross-sectional views showing a configuration example in the vertical direction of a purification cylinder in which the detection method of the present invention can be implemented. 3 and 4 are cross-sectional views showing vertical configuration examples of the gap portion, the communication portion, and the detection portion provided in the purification agent layer of the purification cylinder in which the detection method of the present invention can be implemented. FIG. 5 is a cross-sectional view illustrating an example of a horizontal configuration of the void portion, the communication portion, and the detection portion of the purification cylinder in which the detection method of the present invention can be implemented. FIG. 6 is a perspective view showing an example of a means (a container having a hollow inside) for providing a gap and a communicating portion in the purifier filling portion in the detection method of the present invention.
[0014]
As shown in FIG. 1 and FIG. 2, the purification cylinder used for carrying out the detection method of the present invention includes an introduction port 1 for harmful gas, a purifier filling portion 2, a discharge port 3 for purified gas, and In addition to the detection unit 4, a gap 5 and a communication unit 6 that communicates this with the detection unit are provided in at least a part of the purifier filling unit. These gap portions and communication portions are configured such that the gas introduced into the gap portions easily flows through the communication portion and reaches the detection portion. In the detection method of the present invention, in order to provide a void portion and a communication portion in the purifier filling portion, a container having a hollow inside as shown in FIG. 6 is usually used. Including the case where such a container is used, the gap and the communication portion provided in the purifier filling portion are configured as follows.
[0015]
That is, as shown in FIG. 3 and FIG. 4, the gap portion 5 has an upstream surface 8 of the gas flow 7 (upper surface in the case of downflow, lower surface in the case of upflow) made of a gas permeable material. The downstream surface 9 (the lower surface in the case of downflow, the upper surface in the case of upflow) and the side surface 10 are preferably made of a gas-impermeable material. (In the gaps and communication portions shown in FIGS. 3 and 4, the dotted line indicates the surface of the gas permeable material, and the solid line indicates the surface of the gas non-permeable material.) As a result, the gas that has passed through the purifier layer is easily introduced into the gap, and the once introduced gas is less likely to escape from the downstream surface.
[0016]
For the upstream surface 8 ′ of the gas flow 7, the communication unit 6 is configured as shown in FIGS. 3 (1), (3), (4), (5), (6), or FIGS. 6) may be a gas permeable material, or may be a gas non-permeable material as shown in FIGS. 3 (2) and 4 (2), but it is adjacent to the detection unit. The part surface 11 is made of a gas permeable material. Moreover, the surface which does not adjoin the detection part among the downstream surfaces of a communication part, and the surface which does not adjoin a detection part among side surfaces are preferably comprised with a gas-impermeable material. By setting it as such a structure, the gas introduced from the upstream surface of the space | gap part or a communication part becomes easy to distribute | circulate to a detection part.
[0017]
The gas permeable material used for the gap and the communication part is not particularly limited as long as it has corrosion resistance against harmful gas components and can prevent the entry of the purifier, Reticulated carbon steel, manganese steel, chromium steel, molybdenum steel, stainless steel, etc. can be used. In addition, the gas non-permeable material is not particularly limited as long as it has corrosion resistance against harmful gas components, but usually plate-like carbon steel, manganese steel, chromium steel, molybdenum steel, Stainless steel or the like can be used.
[0018]
In the present invention, the communication part as described above has, for example, an end surface 11 adjacent to the detection part as shown in FIGS. 3 (1) to (3) and FIGS. 4 (1) to (3). It is set to be adjacent to the upstream surface of the gas flow of the detection agent, or is set to be adjacent to the side surface of the detection agent as shown in FIGS. 3 (4) and 4 (4). Further, as shown in FIGS. 3 (5) (6) and 4 (5) (6), the end surface 11 adjacent to the detection unit may not necessarily be in contact with the detection agent 12. The distance between the end surface adjacent to the part and the detection agent is preferably set within 5 cm.
[0019]
In the present invention, the gap portion and the communication portion are not particularly limited in size and shape. However, the total volume of the gap and the communication portion is usually 0.1 to 10%, preferably 0.2 to 5%, of the purifier filling portion. The outer shape of the void portion and the communication portion may be a cube, a rectangular parallelepiped, a sphere, an ellipse, a cone, a truncated cone, a pyramid, a truncated pyramid, a ring, a shape similar to these, a combination of these, or the like. Moreover, about these horizontal arrangement | positioning, what is shown in FIG. 5 can be illustrated. The gas permeable material component (gas introduction part) set on the upstream surface of the gap and the communication part has a total cross-sectional area in the horizontal direction and is usually 1 to 40% of the purifier filling part, preferably The cross-sectional area is 5 to 30%.
[0020]
When carrying out the detection method of the present invention, the purification cylinder is set in the above-described configuration. In the present invention, the filling length of the purification agent filled in the purification cylinder is usually 10 to 200 cm in practice. The flow rate of the harmful gas flowing through the purification cylinder is not particularly limited, but is usually about 0.1 to 50 cm / sec as the empty tube linear velocity. Moreover, there is no restriction | limiting in particular also in temperature and a pressure, Although temperature is normally -20-300 degreeC and a pressure is normal pressure normally, it can implement also from the pressure reduction of 1 kPa (abs) to 1 Mpa (abs). It is.
[0021]
【Example】
EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited by these.
[0022]
Example 1
(Purification tube setting)
As shown in FIG. 6, the surface that becomes the upstream surface side of the gas flow and the surface that becomes the end adjacent to the detection portion are made of mesh-like stainless steel, and the other surface is made of plate-like stainless steel as the gap portion and the communication portion. A container was made. This container is installed in the purification cylinder in the arrangement as shown in FIG. The long side including the gap portion and the communication portion is 350 mm, and the end surface adjacent to the detection portion is 30 mm wide and 10 mm high.
[0023]
Next, potassium hydroxide is added to 100 parts by weight of commercially available hopcalite (manufactured by Nissan Gardler Co., Ltd., extruded product with a diameter of 1.5 mm and a length of 3 to 10 mm) mainly composed of manganese dioxide and copper oxide. A cleaning agent was prepared by loading 30 parts by weight. Further, 100 g of granular silica gel with a specific surface area of 300 m ² / g (Fuji Silysia Chemical Co., Ltd., Caract 10), 1.0 g of phosphomolybdic acid hydrate and cupric sulfate pentahydrate 0 as discoloring components A detection agent was prepared by impregnating a solution of 2 g in 270 mL of water and drying at 75 ° C.
[0024]
A cleaning window made of stainless steel having an inner diameter of 400 mm is filled with the aforementioned cleaning agent so as to have a thickness of 80 mm. Was filled with the above-mentioned detection agent. The detection agent was set so that its upper surface was flush with the upper surface of the cleaning agent.
Next, the container is placed on the upper surface of the purifier so that the four end surfaces are adjacent to the four detection portions, respectively, and the purifier is added so that the total filling length is 400 mm. Filled.
[0025]
(Detection test)
A harmful gas containing 5000 ppm of SiH _{4 in} dry nitrogen was introduced into the aforementioned purification cylinder by downflow under the conditions of normal pressure, 25 ° C. and flow rate 200 L / min, and the time until the detection agent started to change color was measured. . Moreover, a part of the outlet gas of the purification cylinder was sampled, and the time until SiH ₄ was detected (purification agent breakthrough time) was measured. These results are shown in Table 1. In addition, taking into account the filling length of the cleaning agent and the position of the detection agent, the color change start time of the detection agent calculated from the breakthrough time of the purification agent is also shown.
[0026]
Comparative Example 1
A purification cylinder was set in the same manner as in Example 1 using the same purification agent and detection agent as in Example 1 except that the gap and the communication part were not arranged.
SiH ₄ was introduced into the purification cylinder under the same conditions as in Example 1, and the time until the detection agent started to change color and the breakthrough time of the purification agent were measured. These results are shown in Table 1. In addition, taking into account the filling length of the cleaning agent and the position of the detection agent, the color change start time of the detection agent calculated from the breakthrough time of the purification agent is also shown.
[0027]
[Table 1]

[0028]
【The invention's effect】
When purifying harmful gas discharged from a semiconductor manufacturing process or the like by bringing it into contact with a purifying agent filled in a purifying cylinder by the harmful gas detection method of the present invention, a reaction portion with a harmful gas component of the purifying agent Alternatively, it is possible to accurately detect the progress of the adsorbing part of the harmful gas component by the purifier.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a vertical configuration example of a purification cylinder in which the detection method of the present invention can be performed. FIG. 2 is a vertical configuration example of a purification cylinder other than FIG. FIG. 3 is a cross-sectional view showing a vertical configuration example of a void portion, a communication portion, and a detection portion provided in a purification agent layer of a purification cylinder in which the detection method of the present invention can be performed (down flow) If)
FIG. 4 is a cross-sectional view showing a vertical configuration example of a void portion, a communication portion, and a detection portion provided in a purification agent layer of a purification cylinder capable of performing the detection method of the present invention (in the case of upflow).
FIG. 5 is a cross-sectional view showing a horizontal configuration example of a void portion, a communication portion, and a detection portion of a purification cylinder in which the detection method of the present invention can be carried out. FIG. The perspective view which shows the example of the means for providing
1 Hazardous Gas Inlet 2 Purifier Filling Port 3 Purified Gas Exhaust Port 4 Detector (Configuration including Detector and Viewing Window)
5 gap portion 6 communication portion 7 gas flow 8 upstream surface 8 'of the gap portion upstream surface 9 of the communication portion downstream surface 9' of the gap portion downstream surface 10 of the communication portion gap portion or side surface 11 of the communication portion 11 Adjacent end face 12 Detection agent

Claims

A method for purifying noxious gas by introducing noxious gas into a purifying cylinder and bringing it into contact with a purifying agent filled in the purifying cylinder, and detecting a noxious gas component passing through the purifying agent filling portion. A gap that communicates with the detection unit for harmful gas components is provided in at least a part of the filling portion of the agent, and the end of the communication unit adjacent to the detection unit is adjacent to the upstream surface or side surface of the gas flow of the detection unit set the detection method of the harmful gas and detecting the該検intellectual portion harmful gas components contained in the gas flowing from the airspace.

The hazardous gas detection method according to claim 1, wherein the harmful gas component detection unit includes a harmful gas component detection agent and a viewing window.

2. A container in which at least a part of a surface on the upstream surface side of a gas flow and at least a part of a surface adjacent to a detection part are made of a gas permeable material are used as the gap part and the communication part. The detection method of harmful gas as described in 1.

The method for detecting harmful gases according to claim 3, wherein the gas permeable material is a net-like material.

The method for detecting harmful gas according to claim 1, wherein the plurality of harmful gas component detection parts communicating with each other via the gap are installed on the cylindrical wall part of the purification cylinder.