JP4349682B2

JP4349682B2 - Operation method of electrolyzed water generator for cleaning

Info

Publication number: JP4349682B2
Application number: JP12192399A
Authority: JP
Inventors: 琢朗加藤; 一浩久保田
Original assignee: Japan Carlit Co Ltd
Current assignee: Japan Carlit Co Ltd
Priority date: 1999-04-28
Filing date: 1999-04-28
Publication date: 2009-10-21
Anticipated expiration: 2019-04-28
Also published as: JP2000312883A

Description

【０００１】
【発明に属する技術分野】
本発明は、半導体用基板、液晶表示素子用基板等、清浄度が要求される基板表面の洗浄に用いられる洗浄用電解水生成装置の運転方法に関し、特に洗浄用電解水の不要時の運転方法に関する。
【０００２】
【従来の技術】
半導体用基板、液晶表示素子用基板等、清浄度が要求される基板表面の洗浄は、塩酸／過水、アンモニア／過水及び希フッ酸を基準にした洗浄が広く行われてきた。この方法は、米国ＲＣＡ社が電子管の洗浄のために開発したＲＣＡ洗浄を基本に改良されたものである。
【０００３】
近年、環境問題が注視され、環境負荷のより低い洗浄方法が求められてきており、また、経済性に優れたより低コストの洗浄方法が求められてきている。
【０００４】
さらに、回路パターンの微細化、ＬＳＩの高密度化、高集積化、高性能化の進展に伴い、半導体製造プロセスでの清浄度の要求も、従来にも増して高まってきている。
【０００５】
特開平１０−２８６５７１号公報には、固体高分子電解質（以下「ＳＰＥ」と略記）隔膜を用いた二室型電解槽に、純水または超純水を供給させ、直流電流を通電、電気分解させて、陽極室から酸化性洗浄用電解水、陰極室から還元性洗浄用電解水ほ生成させる方法が開示されており、得られた洗浄用電解水は、シリコンウエハのＣＭＰ後洗浄等で用いられる。
【０００６】
ＣＭＰ後洗浄等に用いられる洗浄用電解水は、非常に高い清浄度が求められ、特に金属不純物については極微量でも問題とされている。
【０００７】
洗浄用電解水生成装置に用いられる電極は、一般に水の電気分解により酸素発生能を持つ金属電極であり、その中でも金属不純物の溶出の少ない、例えば、白金族金属を活性層とした電極が用いられる。
【０００８】
洗浄用電解水生成装置の通常運転時では、上記電極からの金属不純物の溶出はほとんどないが、通常運転用電源の遮断時には、一瞬逆電流が流れ、金属不純物が溶出すると共に、電源遮断後の通常運転再開始から定常状態になるまでの立ち上がり時間に数時間を要するため問題となる。また、イリジウム系金属を活性層として用いた電極は、通常運転用電源の遮断中に還元され、金属不純物の溶出が容易に起こり、かつ触媒能が失活してしまうという問題がある。
【０００９】
上記の問題を回避するため、例えば、洗浄用電解水の不要時にも通電する方法が考えられるが、通常運転と同じ運転を行ったのでは、生成された洗浄用電解水はむだに排水され、また供給水及び通電した電力もむだに消費されることとなり、非経済的である。
【００１０】
特開平１０―９９８６１号公報には、通常運転用電源の遮断時にも1.2Ｖ以上の電圧及び／または20mＡ／dm²以上の電流を印可し、逆電流の発生を防止する方法が開示されており、電極物質の溶出による電解液の汚染と電極の失活を抑制している。しかしながら、特開平１０―９９８６１号公報では、通常運転用電源の他に、補助電源を別に用意しなくてはならず、また、通常運転再開始時から定常状態になるまで立ち上がり時間がかかってしまうという解決すべき点が残っていた。
【００１１】
【発明が解決しようとする課題】
本発明の目的は、上記問題を解決し得る、洗浄水の不要時の運転でも金属不純物が溶出せず、通常運転再開始時からの立ち上がり時間が早く、補助電源も不要の経済性に優れた洗浄用電解水の運転方法を提供することである。
【００１２】
【課題を解決するための手段】
本発明者らは、鋭意研究を重ねた結果、洗浄用電解水の不要時に、供給水量及び通電電流を特定の範囲に減少させることにより、上記課題が解決されることを見出し、本発明を完成するに至った。
【００１３】
すなわち、本発明は、ＳＰＥ隔膜を用いた二室型電解槽に、純水または超純水を供給させ、直流電流を通電、電気分解させる洗浄用電解水生成装置の運転方法において、洗浄用電解水の不要時に、供給量を通常運転時の１／20〜１／５に減少させると共に通電電流を通常運転時の１／20〜１／５に減少させることを特徴とする洗浄用電解水生成装置の運転方法である。
【００１４】
また、本発明は、ＳＰＥ隔膜を用いた二室型電解槽に、純水または超純水を供給させ、直流電流を通電、電気分解させる洗浄用電解水生成装置の運転方法において、洗浄用電解水の不要時に、供給量を通常運転時の１／20〜１／５に減少させ、かつ間欠通水とすると共に、通電電流を通常運転時の１／20〜１／５に減少させることを特徴とする洗浄用電解水生成装置の運転方法である。
【００１５】
以下、本発明について、詳細に説明する。
【００１６】
本発明に用いられる電解槽は、ＳＰＥ隔膜の両側面に、順次、陽極及び陰極、給電体、テフロン製槽体が配されてなる二室型電解槽であり、純水または超純水を供給させ、直流電流を通電させることにより、洗浄用電解水を生成させるものである。
【００１７】
本発明に用いられる二室型電解槽は、単一槽または複数槽のどちらでもよい。
【００１８】
本発明に用いられるＳＰＥ隔膜は、テフロン製陽イオン交換膜であり、１枚でも複数枚重ねて使用してもよい。
【００１９】
本発明に用いられる陽極及び陰極は、気液透過性があるバルブ金属基体上に、白金、酸化白金、タンタル、酸化タンタル及び／または酸化イリジウムから選ばれた少なくとも１種以上を活性層として被覆させたものであり、特に、酸化イリジウムを主成分とする活性層を被覆させた陽極は、通常運転時の金属不純物の溶出が最も少なく好ましい。
【００２０】
上記の陽極及び陰極を用いた場合、通常運転時には、金属不純物がほとんど溶出しないが、洗浄用電解水の不要時に、通常運転用電源を遮断させると、一瞬逆電流が流れ、金属不純物が溶出すると共に、電源遮断後の通常運転再開始から定常状態になるまでの立ち上がり時間に数時間を要する。また、酸化イリジウムを含む活性層を被覆させた陽極では、通常運転用電源の遮断中に還元され、金属不純物が容易に溶出する上、触媒能も失活してしまう。
【００２１】
本発明の運転方法では、洗浄用電解水の不要時には、供給水量を通常運転時の１／20〜１／５に減少させると共に通電電流を通常運転時の１／20〜１／５に減少させて運転させる。
【００２２】
上記の運転方法では、通常運転再開始時からの立ち上がり時間が数分以内である。
【００２３】
供給水量が、通常運転時の１／20未満の場合、流量制御が難しく、また１／５より超の場合、排水量が多くなり、経済的に不都合である。
【００２４】
通電電流が、通常運転時の１／20未満の場合、金属不純物が溶出し不都合であり、１／５より超の場合、経済的に不都合である。
【００２５】
洗浄用電解水の不要時運転での供給水量と通電電流は、上記の範囲であれば、任意に設定できるが、通常運転での供給水量と通電電流に対し、不要時運転での供給水量と通電電流をほぼ同じ割合で減少させると、通常運転の再開始から定常状態になるまでの立ち上がり時間が短縮でき好ましい。
【００２６】
また、本発明の運転方法では、洗浄用電解水の不要時には、供給水量を通常運転時の１／20〜１／５に減少させ、間欠通水させると共に、通電電流を通常運転時の１／20〜１／５に減少させて運転させる。
【００２７】
間欠通水は、１〜10分通水を停止させ、１分間通水させることにより行われる。
【００２８】
間欠通水を行うことにより、通常運転再開始時の立ち上がり時間は、間欠通水を行わない場合の数分以内から約２割程増加するが、供給水量がより削減できる。
【００２９】
本発明の運転方法によれば、陽極及び陰極からの金属不純物が溶出せず、また、酸化イリジウム含む活性層を被覆させた陽極の場合でも、活性層が還元されず、金属不純物も溶出せず、触媒能も失活しない。
【００３０】
洗浄用電解水の不要時に通常運転用電源を遮断させる従来方法では、通常運転再開始時からの立ち上がり時間が数時間要するのに対し、本発明の運転方法によれば、立ち上がり時間が数分以内であり、非常に短縮される。
【００３１】
本発明では、洗浄用電解水の不要時の供給水量及び通電電流を、通常運転時より減少させて運転させるため、供給水量及び電力量が削減できる。
【００３２】
本発明の運転方法では、通常運転用電源以外の補助電源を別途用意する必要がない。
【００３３】
【発明の実施の形態】
以下、発明の実施の形態を、実施例に基き説明する。なお、本発明は、実施例になんら限定されない。
【００３４】
実施例１
本発明に用いた二室型電解槽は、以下のように作製した。
【００３５】
ＳＰＥ隔膜（登録商標：ナフィオン１１７、(株)デュポン製）を２枚重ね合わせ、その両側面に、リング状チタン基体表面に焼成法により酸化白金を被覆させた給電体を溶接したエキスパンド基体表面に焼成法により酸化イリジウムを被覆させた陽極と、同上の給電体を溶接したポーラスチタン基体表面に焼成法により酸化白金を被覆させた陰極とを各々配置させ、さらにその両外側面にテフロン製槽体を各々配置させた後、最外側面より締付用端板で締め付けて、ＳＰＥ隔膜で分離された陽極室及び陰極室を有する二室型電解槽を作製した。電極の活性面は、1.5dm²とした。
【００３６】
陽極室及び陰極室に、供給水として超純水を２Ｌ／分で各々供給させ、印加電圧約３Ｖ、15Ａの定電流で通電させ、電気分解させて通常運転を行い、陰極室から中性の酸化性洗浄用電解水を、陰極室より中性の還元性洗浄用電解水を生成させた。
【００３７】
ＯＲＰ計（電気化学計器(株)製ＨＢＭ−１０２）を用いて、陽極室からの洗浄用電解水を測定したところ、供給水のＯＲＰと比べ＋80mＶであった。
【００３８】
また、誘導結合プラズマ重量分析装置（横河電機(株)製ＰＭＳ２０００）を用いて、陽極室からの洗浄用電解水中の金属不純物（Ｂ、Ｎa、Ｍg、Ａl、Ｋ、Ｃa、Ｔｉ、Ｃr、Ｍn、Ｆe、Ｎｉ、Ｃu、Ｚn、Ｓn、Ｂa、Ｗ、Ｉr、Ｐt、Ｔa、Ｐb）を測定したところ、全て検出されなかった。
【００３９】
また、陰極室からの洗浄用電解水のＯＲＰは、供給水と比べ−410mＶであり、洗浄用電解水中の金属不純物は、全て検出されなかった。
【００４０】
さらに、上記電解槽を用いて、供給水量を0.2Ｌ／分とし、印加電圧約２Ｖ、1.5Ａの定電流で、洗浄用電解水の不要時運転を、10日間行った後、超純水供給量を２Ｌ／分とし、印加電圧約３Ｖ、15Ａの定電流で、通常運転を再開した。不要時運転後、通常運転再開始から定常状態までの立ち上がり時間は、５分であった。
【００４１】
通常運転再開始後の陽極室及び陰極室からの洗浄用電解水のＯＲＰ及び洗浄用電解水中の金属不純物は、不要時運転前の通常運転と同じであった。
【００４２】
また、洗浄用電解水の不要時運転中に消費された超純水は、2.9m³であり、消費電力量は、650Ｗhrであった。
【００４３】
本発明の運転方法では、洗浄用電解水の不要時でも金属不純物が溶出せずまた触媒能の失活もなく、通常運転再開始後の洗浄用電解水は、不要時運転前の通常運転と同等ものが得られた。また、通常運転再開始からの立ち上がり時間が非常に早い。
【００４４】
実施例２
実施例１において、洗浄用電解水の不要時運転で、５分間通水を停止させ、１分間通水させる間欠通水とした以外は、実施例１と同様にして、運転した。不要時運転後、通常運転再開始からの立ち上がり時間は、６分であった。
【００４５】
不要時運転前の通常運転での洗浄用電解水について、実施例１と同様にして測定したところ、陽極室からの洗浄用電解水のＯＲＰは、供給水と比べ＋100mＶであり、金属不純物は、全て検出されず、陰極室からの洗浄用電解水のＯＲＰは、供給水と比べ−420ｍＶであり、金属不純物は、全て検出されなかった。
【００４６】
通常運転再開始後の洗浄用電解水のＯＲＰ、洗浄用電解水中の金属不純物は、不要時運転前の通常運転と同じであった。
【００４７】
また、洗浄用電解水の不要時運転中に消費された供給水量は、0.5m³であり、実施例１の約１／６であった。また消費電力量は、650Ｗhrであった。
【００４８】
比較例１
実施例１において、洗浄用電解水の不要時運転も、通常運転と同様にして、運転した。
【００４９】
陽極室からの洗浄用電解水のＯＲＰは、供給水と比べ＋90mＶであり、金属不純物は、全て検出されず、また陰極室からの洗浄用電解水のＯＲＰは、供給水と比べ−400ｍＶであり、金属不純物は、全て検出されなかった。
【００５０】
洗浄用電解水の不要時運転に消費された供給水量は、29m³であり、実施例１の10倍であった。また消費電力量は、11,000Ｗhrであった。
【００５１】
比較例２
実施例１において、洗浄用電解水の不要時運転で、通水及び通電を停止させた以外は、実施例１と同様にして、運転した。不要時運転後、通常運転再開始から３時間で定常状態となった。
【００５２】
不要時運転前の通常運転での洗浄用電解水について、実施例１と同様にして測定したところ、陽極室からの洗浄用電解水のＯＲＰは、供給水と比べ＋100mＶであり、金属不純物は、全て検出されず、陰極室からの洗浄用電解水のＯＲＰは、供給水と比べ−410mＶであり、金属不純物は、全て検出されなかった。
【００５３】
通常運転再開始後の陽極室からの洗浄用電解水のＯＲＰは、不要時運転前の通常運転と同じであったが、金属不純物は、Ｉrが520pptであり、陽極からの金属不純物の溶出が確認された。一方、陰極室からの洗浄用電解水のＯＲＰ、金属不純物は、不要時運転前の通常運転と同じであった。
【００５４】
比較例３
実施例１において、洗浄用電解水の不要時運転で、通水を停止させると共に電圧を２Ｖ印可させた以外は、実施例１と同様にして、運転したところ、不要時運転の３日目で、電圧が急激に低下し、電解不能となった。電解槽を分解したところ、電解槽内の水がなくなっており、ＳＰＥ隔膜が電極に溶着し、陽極と陰極とが短絡していた。
【００５５】
【発明の効果】
本発明の運転方法によれば、洗浄用電解水の不要時運転でも、陽極及び陰極からの金属不純物の溶出はなく、通常運転再開時後も、不要時運転前の通常運転で得られたと同じ、非常に清浄度の高い洗浄用電解水を得ることができる。
【００５６】
本発明の運転方法では、不要時運転後の通常運転再開始から定常状態となるまでの立ち上がり時間が数分以内となり、非常に早い。
【００５７】
本発明では、洗浄用電解水の不要時に、供給水量及び通電電流を通常運転より減少させて運転させるため、消費される供給水量及び電力量が削減でき、経済的である。
【００５８】
本発明の運転方法では、通常運転用電源をそのまま用いることができ、補助電源を別に用意する必要がない。[0001]
[Technical field belonging to the invention]
The present invention relates to an operation method of a cleaning electrolyzed water generating apparatus used for cleaning a substrate surface such as a semiconductor substrate or a liquid crystal display element substrate that requires cleanliness, and in particular, an operation method when cleaning electrolytic water is unnecessary. About.
[0002]
[Prior art]
Cleaning of substrates such as semiconductor substrates and liquid crystal display element substrates that require cleanliness has been widely performed based on hydrochloric acid / overwater, ammonia / overwater, and dilute hydrofluoric acid. This method is an improvement based on the RCA cleaning developed by the US RCA for cleaning the electron tube.
[0003]
In recent years, attention has been paid to environmental problems, and there has been a demand for a cleaning method with a lower environmental load. In addition, there has been a demand for a lower cost cleaning method with excellent economic efficiency.
[0004]
Furthermore, with the progress of miniaturization of circuit patterns, higher density of LSIs, higher integration, and higher performance, the demand for cleanliness in the semiconductor manufacturing process is increasing more than ever.
[0005]
In Japanese Patent Laid-Open No. 10-286571, pure water or ultrapure water is supplied to a two-chamber electrolytic cell using a solid polymer electrolyte (hereinafter abbreviated as “SPE”) diaphragm, a direct current is applied, and electrolysis is performed. A method of generating electrolytic water for oxidizing cleaning from the anode chamber and electrolytic water for reducing cleaning from the cathode chamber is disclosed, and the obtained electrolytic water for cleaning is used for post-CMP cleaning of silicon wafers, etc. It is done.
[0006]
The electrolytic water for cleaning used for post-CMP cleaning or the like is required to have a very high cleanliness, and particularly a trace amount of metal impurities is a problem.
[0007]
The electrode used in the electrolyzed water generator for cleaning is generally a metal electrode capable of generating oxygen by electrolysis of water, and among them, an electrode with a small amount of elution of metal impurities, for example, an active layer made of a platinum group metal is used. It is done.
[0008]
During normal operation of the electrolyzed water generator for cleaning, there is almost no elution of metal impurities from the electrode, but when the power supply for normal operation is shut off, a reverse current flows for a moment, metal impurities are eluted, This is a problem because it takes several hours for the rise time from the restart of normal operation to the steady state. In addition, an electrode using an iridium-based metal as an active layer is reduced while the power supply for normal operation is shut off, and there is a problem that elution of metal impurities occurs easily and the catalytic ability is deactivated.
[0009]
In order to avoid the above problem, for example, a method of energizing when the electrolytic water for cleaning is unnecessary is conceivable, but when performing the same operation as the normal operation, the generated electrolytic water for cleaning is wastefully drained, In addition, the supplied water and the energized electric power are wasted, which is uneconomical.
[0010]
Japanese Patent Laid-Open No. 10-99861 discloses a method for preventing the occurrence of reverse current by applying a voltage of 1.2 V or higher and / or a current of 20 mA / dm ² or higher even when the power supply for normal operation is shut off. This suppresses the electrolyte contamination and electrode deactivation due to elution of the electrode material. However, in Japanese Patent Application Laid-Open No. 10-99861, an auxiliary power source must be prepared separately from the normal operation power source, and it takes a rise time from the normal operation restart to the steady state. The point to be solved still remained.
[0011]
[Problems to be solved by the invention]
The object of the present invention is to solve the above problems, metal impurities do not elute even when the washing water is unnecessary, the rise time from the normal operation restart time is fast, and the auxiliary power source is unnecessary and excellent in economic efficiency. It is to provide a method for operating electrolytic water for cleaning.
[0012]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by reducing the amount of supplied water and energization current to a specific range when electrolytic water for washing is unnecessary, and the present invention has been completed. It came to do.
[0013]
That is, the present invention relates to a cleaning electrolysis apparatus in a method for operating a cleaning electrolyzed water generating apparatus in which pure water or ultrapure water is supplied to a two-chamber electrolytic cell using an SPE diaphragm, and direct current is applied and electrolyzed. Electrolytic water generation for cleaning, characterized in that when water is not required, the supply amount is reduced to 1/20 to 1/5 of normal operation and the energization current is reduced to 1/20 to 1/5 of normal operation It is the operation method of an apparatus.
[0014]
The present invention also relates to a cleaning electrolysis apparatus in a method for operating a cleaning electrolyzed water generator in which pure water or ultrapure water is supplied to a two-chamber electrolytic cell using an SPE diaphragm, and direct current is applied and electrolyzed. When water is not needed, the supply amount is reduced to 1/20 to 1/5 of normal operation, and intermittent water flow is performed, and the energization current is reduced to 1/20 to 1/5 of normal operation. It is the operating method of the electrolysis water generating device for washing characterized.
[0015]
Hereinafter, the present invention will be described in detail.
[0016]
The electrolytic cell used in the present invention is a two-chamber electrolytic cell in which an anode, a cathode, a power feeder, and a Teflon tank are sequentially arranged on both sides of the SPE diaphragm, and supplies pure water or ultrapure water. Then, by supplying a direct current, cleaning electrolyzed water is generated.
[0017]
The two-chamber electrolytic cell used in the present invention may be either a single cell or a plurality of cells.
[0018]
The SPE diaphragm used in the present invention is a cation exchange membrane made of Teflon, and may be used alone or in a plurality.
[0019]
In the anode and cathode used in the present invention, at least one selected from platinum, platinum oxide, tantalum, tantalum oxide and / or iridium oxide is coated as an active layer on a gas-liquid permeable valve metal substrate. In particular, an anode coated with an active layer containing iridium oxide as a main component is preferable because it has the least elution of metal impurities during normal operation.
[0020]
When the above anode and cathode are used, metal impurities hardly elute during normal operation, but when the electrolysis water for cleaning is not required, if the power supply for normal operation is shut off, a reverse current flows for a moment and metal impurities are eluted. At the same time, it takes several hours for the rising time from the restart of normal operation after power-off to the steady state. In addition, the anode coated with the active layer containing iridium oxide is reduced during the shut-off of the power supply for normal operation, so that metal impurities are easily eluted and the catalytic ability is deactivated.
[0021]
In the operation method of the present invention, when the electrolytic water for washing is not required, the amount of supplied water is reduced to 1/20 to 1/5 of the normal operation and the energization current is reduced to 1/20 to 1/5 of the normal operation. To drive.
[0022]
In the above operation method, the rise time from the restart of normal operation is within a few minutes.
[0023]
When the amount of supplied water is less than 1/20 in normal operation, it is difficult to control the flow rate, and when it exceeds 1/5, the amount of drainage increases, which is economically inconvenient.
[0024]
When the energizing current is less than 1/20 in normal operation, metal impurities are eluted, which is inconvenient. When it exceeds 1/5, it is economically inconvenient.
[0025]
The supply water amount and energization current in the electrolysis water for cleaning when it is not required can be set arbitrarily within the above range, but the supply water amount and operation current in the normal operation can be Decreasing the energization current at approximately the same rate is preferable because the rise time from the restart of normal operation to the steady state can be shortened.
[0026]
Further, in the operation method of the present invention, when the electrolytic water for washing is unnecessary, the amount of supplied water is reduced to 1/20 to 1/5 of the normal operation, intermittent water is passed, and the energization current is reduced to 1 / of the normal operation. Reduce to 20 to 1/5.
[0027]
The intermittent water flow is performed by stopping water flow for 1 to 10 minutes and allowing water to flow for 1 minute.
[0028]
By performing intermittent water flow, the rise time when restarting normal operation is increased by about 20% from within a few minutes when intermittent water flow is not performed, but the amount of supplied water can be further reduced.
[0029]
According to the operation method of the present invention, metal impurities from the anode and the cathode are not eluted, and even in the case of the anode coated with the active layer containing iridium oxide, the active layer is not reduced and the metal impurities are not eluted. The catalytic ability is not deactivated.
[0030]
In the conventional method in which the power supply for normal operation is cut off when the electrolytic water for washing is not required, the rise time from the restart of normal operation takes several hours, whereas according to the operation method of the present invention, the rise time is within a few minutes. And is greatly shortened.
[0031]
In the present invention, since the amount of supplied water and the energization current when cleaning electrolyzed water is unnecessary are reduced from those during normal operation, the amount of supplied water and the amount of power can be reduced.
[0032]
In the operation method of the present invention, it is not necessary to separately prepare an auxiliary power source other than the normal operation power source.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the invention will be described based on examples. The present invention is not limited to the examples.
[0034]
Example 1
The two-chamber electrolytic cell used in the present invention was produced as follows.
[0035]
Two sheets of SPE diaphragm (registered trademark: Nafion 117, manufactured by DuPont Co., Ltd.) are overlaid on both sides, and the surface of the expanded base is welded with a power supply body coated with platinum oxide by a firing method on the surface of a ring-shaped titanium base. An anode coated with iridium oxide by a firing method, and a cathode coated with platinum oxide by a firing method on the surface of a porous titanium substrate welded with the same power supply body as described above, and a Teflon tank body on both outer surfaces thereof After each was placed, a two-chamber electrolytic cell having an anode chamber and a cathode chamber separated by an SPE diaphragm was fabricated by tightening with an end plate for tightening from the outermost surface. The active surface of the electrode was 1.5 dm ² .
[0036]
Ultra pure water is supplied to the anode chamber and the cathode chamber at a rate of 2 L / min., The applied voltage is about 3 V, a constant current of 15 A, and electrolysis is performed for normal operation. Electrolytic water for oxidizing cleaning was generated from the cathode chamber with neutral reducing cleaning electrolytic water.
[0037]
When the electrolytic water for cleaning from the anode chamber was measured using an ORP meter (HBM-102 manufactured by Electrochemical Instrument Co., Ltd.), it was +80 mV compared to the ORP of the feed water.
[0038]
Further, using an inductively coupled plasma gravimetric analyzer (PMS2000 manufactured by Yokogawa Electric Corporation), metal impurities (B, Na, Mg, Al, K, Ca, Ti, Cr, When Mn, Fe, Ni, Cu, Zn, Sn, Ba, W, Ir, Pt, Ta, and Pb) were measured, all were not detected.
[0039]
Further, the ORP of the cleaning electrolyzed water from the cathode chamber was −410 mV compared to the supply water, and all metal impurities in the cleaning electrolyzed water were not detected.
[0040]
Furthermore, using the above electrolytic cell, the supply water amount is 0.2 L / min, the applied voltage is about 2 V, the constant current of 1.5 A, and the electrolysis water for washing is unnecessary for 10 days. Normal operation was resumed at an applied voltage of about 3 V and a constant current of 15 A at an amount of 2 L / min. After the unnecessary operation, the rise time from the restart of the normal operation to the steady state was 5 minutes.
[0041]
The ORP for the cleaning electrolyzed water from the anode chamber and the cathode chamber after restarting the normal operation and the metal impurities in the cleaning electrolyzed water were the same as the normal operation before the unnecessary operation.
[0042]
Moreover, the ultrapure water consumed during the operation when the electrolytic water for washing was unnecessary was 2.9 m ³ and the power consumption was 650 Whr.
[0043]
In the operation method of the present invention, the metal impurities are not eluted even when the electrolytic water for washing is unnecessary, and the catalytic ability is not deactivated, and the electrolytic water for washing after the normal operation is restarted is the normal operation before the unnecessary operation. The equivalent was obtained. Also, the rise time from the restart of normal operation is very fast.
[0044]
Example 2
In Example 1, the operation was performed in the same manner as in Example 1 except that the cleaning electrolysis water was not required and the water flow was stopped for 5 minutes and the intermittent water flow was performed for 1 minute. The rise time from the restart of normal operation after the unnecessary operation was 6 minutes.
[0045]
About the electrolysis water for washing | cleaning in the normal driving | operation before an unnecessary time, when measured similarly to Example 1, ORP of the electrolysis water for washing | cleaning from an anode chamber is + 100mV compared with supply water, Metal impurities are Not all were detected, and the ORP for cleaning electrolysis water from the cathode chamber was −420 mV compared to the supply water, and all metal impurities were not detected.
[0046]
The ORP for washing electrolyzed water after the restart of normal operation and the metal impurities in the washing electrolyzed water were the same as in the normal operation before the unnecessary operation.
[0047]
In addition, the amount of supplied water consumed during the operation when the electrolytic water for washing was unnecessary was 0.5 m ³ , which was about 1/6 of that in Example 1. The power consumption was 650 Whr.
[0048]
Comparative Example 1
In Example 1, the electrolysis water for cleaning when not required was operated in the same manner as the normal operation.
[0049]
The ORP for cleaning electrolytic water from the anode chamber is +90 mV compared to the supply water, and all metal impurities are not detected, and the ORP for cleaning electrolytic water from the cathode chamber is −400 mV compared to the supply water. All metal impurities were not detected.
[0050]
The amount of water consumed in the operation when the electrolytic water for washing was unnecessary was 29 m ³ , 10 times that of Example 1. The power consumption was 11,000 Whr.
[0051]
Comparative Example 2
In Example 1, the operation was performed in the same manner as in Example 1 except that the water supply and the energization were stopped in the operation when the electrolytic water for washing was unnecessary. After operation when not required, steady state was reached in 3 hours from the restart of normal operation.
[0052]
About the electrolysis water for washing | cleaning in the normal driving | operation before an unnecessary time, when measured similarly to Example 1, ORP of the electrolysis water for washing | cleaning from an anode chamber is + 100mV compared with supply water, Metal impurities are Not all were detected, and the ORP for cleaning electrolysis water from the cathode chamber was −410 mV compared to the supply water, and all metal impurities were not detected.
[0053]
The ORP for cleaning electrolysis water from the anode chamber after restarting normal operation was the same as the normal operation prior to operation when not required, but the metal impurity was Ir of 520 ppt, and the metal impurity eluted from the anode. confirmed. On the other hand, the ORP for cleaning electrolysis water from the cathode chamber and the metal impurities were the same as in the normal operation before the unnecessary operation.
[0054]
Comparative Example 3
In Example 1, the operation was performed in the same manner as in Example 1 except that the water flow was stopped and the voltage was applied at 2 V in the operation of cleaning electrolytic water when unnecessary. The voltage suddenly dropped and electrolysis became impossible. When the electrolytic cell was disassembled, there was no water in the electrolytic cell, the SPE diaphragm was welded to the electrode, and the anode and the cathode were short-circuited.
[0055]
【The invention's effect】
According to the operation method of the present invention, metal impurities are not eluted from the anode and the cathode even when the electrolysis water for washing is unnecessary, and the same as that obtained in the normal operation before the unnecessary operation after resuming the normal operation. The electrolyzed water for cleaning with a very high cleanliness can be obtained.
[0056]
In the operation method of the present invention, the rise time from the restart of the normal operation after the unnecessary operation to the steady state is within several minutes, which is very fast.
[0057]
In the present invention, when the electrolytic water for washing is not required, the operation is performed by reducing the amount of supplied water and the energized current from the normal operation, so that the amount of supplied water and the amount of power consumed can be reduced, which is economical.
[0058]
In the operation method of the present invention, the normal operation power source can be used as it is, and it is not necessary to prepare an auxiliary power source separately.

Claims

In the operation method of the electrolyzed water generator for cleaning, which supplies pure water or ultrapure water to a two-chamber electrolytic cell using a solid polymer electrolyte membrane, and directs and electrolyzes direct current, cleaning electrolyzed water is unnecessary. Sometimes, the amount of supplied water is reduced to 1/20 to 1/5 of normal operation, and intermittent water flow is performed, and the energization current is reduced to 1/20 to 1/5 of normal operation. A method of operating the electrolyzed water generator for cleaning.

The method of operating an electrolyzed water generator for cleaning according to claim 1 , wherein the intermittent water flow is a water flow of about 1 minute at intervals of 1 to 10 minutes.

3. The cleaning electrolyzed water generating device according to claim 1 or 2 , wherein the cleaning water supply amount and the energizing current are reduced at substantially the same rate with respect to the normal operation water supply amount and the energizing current. Driving method.