JPS59105545A - Measurement of hydrogen ion concentration of electroplating bath - Google Patents

Measurement of hydrogen ion concentration of electroplating bath

Info

Publication number
JPS59105545A
JPS59105545A JP21462282A JP21462282A JPS59105545A JP S59105545 A JPS59105545 A JP S59105545A JP 21462282 A JP21462282 A JP 21462282A JP 21462282 A JP21462282 A JP 21462282A JP S59105545 A JPS59105545 A JP S59105545A
Authority
JP
Japan
Prior art keywords
indicator
solution
absorbancy
hydrogen ion
ion concentration
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP21462282A
Other languages
Japanese (ja)
Inventor
Takashi Ochiai
崇 落合
Yasuo Iguma
康夫 猪熊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Sumitomo Metal Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Priority to JP21462282A priority Critical patent/JPS59105545A/en
Publication of JPS59105545A publication Critical patent/JPS59105545A/en
Pending legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
    • G01N21/80—Indicating pH value

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Plasma & Fusion (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)

Abstract

PURPOSE:To make it possible to measure the pH of an electroplating bath with good accuracy within a short time, by a method wherein the absorbancy of the pH indicator to be added to the electroplating bath is measured at the isosbestic point thereof and the error based on the change in the flow amount of an indicator solution and the deterioration thereof with the elapse of time is corrected by using the measured value. CONSTITUTION:A pH-indicator having a wavelength not changed in absorbancy by pH(called as an isosbestic point), for example, m-cresol purple has a wavelength changed by pH of 525nm at an isosbestic point of 478nm. This indicator solution is sent from a storage tank 3 through a valve 5 and mixed with an electroplating bath 1 in a mixer 6 while the liquid mixture is sent to an absorbancy measuring cell 7. Light is irradiated from a light source 8 while pervious light and reflected light of a half-mirror 9 are respectively passed through interference filters 10, 11, detectors 12, 13 and electric signal converters 13, 14 to calculate the ratio of the absorbancy A525-B525 in an indicator mixed case A and the absorbancy A478- B478 in an indicator non-mixed case B while this ratio is substituted for a preliminarily calculated pH conversion formula to calculate pH with good accuracy. The manipulations of pumps 2, 4 and a valve 5, operation and recording are automatically performed by a treatment apparatus 16.

Description

【発明の詳細な説明】 本発明は、電気めっき液の水素イオン濃度を正確にしか
も短時間のうちに測定する方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for accurately and quickly measuring the hydrogen ion concentration of an electroplating solution.

電気めっき液の水素イオン濃度は、電流効率に大きな影
響を及ばずため、厳密に制御することを必要とされる。The hydrogen ion concentration of the electroplating solution does not have a large effect on current efficiency, and therefore needs to be strictly controlled.

特に、電気めっき液が水酸化物のような沈澱を生成し易
い成分を含む場合、その沈澱生成を抑制するうえでも、
厳密な水素イオン濃度の制御が必要とされる。この目的
で、従来性われている測定方法としては、次のようなも
のがある。In particular, when the electroplating solution contains components that tend to form precipitates, such as hydroxides, in order to suppress the formation of precipitates,
Strict control of hydrogen ion concentration is required. Conventional measurement methods for this purpose include the following.

ｏｐＨガラス電極を用いる方法 測定対象溶液に田ガラス電極を浸漬し、電極の起電力を
測定する簡単な方法である。しかし、ガラス電極あるい
は比較電極の経時変化に起因して起電力が変化するため
、長時間にわたり高測定精度を維持するのは困難である
。また、その経時変化に起因する誤差を相殺する補正を
煩雑に行ったとしても、測定精度を０．１ｐＨ以下の誤
差範囲に維持することは、極めて困難である。Method using an OPH glass electrode This is a simple method in which a glass electrode is immersed in the solution to be measured and the electromotive force of the electrode is measured. However, since the electromotive force changes due to changes in the glass electrode or the reference electrode over time, it is difficult to maintain high measurement accuracy over a long period of time. Further, even if a complicated correction is performed to offset the error caused by the change over time, it is extremely difficult to maintain the measurement accuracy within an error range of 0.1 pH or less.

０中和滴定法 電気めっき液は水素イオン濃度が比較的高い場合が多い
ので、その測定には中和滴定法もよく用いられる〔鉄と
鋼６８（１９８２）Ａ６５参照〕。0 Neutralization titration method Since electroplating solutions often have a relatively high hydrogen ion concentration, the neutralization titration method is also often used for measurement [see Tetsu to Hagane 68 (1982) A65].

この方法は高濃度の酸に対し優れた再現性を持っている
。しかし、中和されるまでに消費した塩基量が必ずしも
滴定前の被〆液の水素イオン濃度を表しているものとは
限らない。例えば、比較的酸性領域で水酸基との錯体を
形成し易いＦｅ３＋やＺｎ２＋を含むめっき液では、中
和点に達する前に水酸基を消費してしまう。これが、こ
の方法における測定誤差の原因となる。This method has excellent reproducibility for high acid concentrations. However, the amount of base consumed until neutralization does not necessarily represent the hydrogen ion concentration of the liquid to be titrated. For example, in a plating solution containing Fe3+ or Zn2+, which tend to form complexes with hydroxyl groups in a relatively acidic region, the hydroxyl groups will be consumed before reaching the neutralization point. This causes measurement errors in this method.

このような測定誤差を生じることなく、簡単にしかも短
時間のうちに高精度の測定を可能としたのが本発明であ
る。The present invention makes it possible to easily and quickly perform highly accurate measurements without causing such measurement errors.

ところで、−によって色調の変化する…指示薬を用い、
吸光度変化の大きい特定の波長の吸光度を測定すること
により、…を求めることが知られている。そこで、めっ
き液に−Ｉ指示薬を一定量添加し、指示薬の吸収による
吸光度変化を測定することにより、めっき液の水素イオ
ン濃度を求めることが推定される。しかし、この方法に
は、以下に（１）〜（３）で示す誤差要因があり、−ガ
ラス電極を用いる測定方法以上の精度を得るのは容易で
ない。By the way, the color tone changes depending on -...using an indicator,
It is known that... can be determined by measuring the absorbance at a specific wavelength with a large change in absorbance. Therefore, it is presumed that the hydrogen ion concentration of the plating solution is determined by adding a certain amount of -I indicator to the plating solution and measuring the change in absorbance due to absorption of the indicator. However, this method has error factors shown in (1) to (3) below, and it is not easy to obtain accuracy higher than the measurement method using a glass electrode.

（１）　　被検液であるめっき液に対して一指示薬の溶
液を添加することは、被検液を希釈することになり、水
素イオン濃度の変化をもたらす。このため、めっき液と
ｐＨ指示薬の溶液とを連続的に混合するために用いられ
る定流量ポンプの流量比を大きくする必要がある。しか
し、特に微少流量にする必要がある岨指示薬の溶液を送
給するポンプの流量を長時間にわたり一定に保つのは実
際上困難であり、これが誤差を生じる原因となる。(1) Adding a solution of one indicator to the plating solution, which is the test solution, dilutes the test solution, resulting in a change in the hydrogen ion concentration. Therefore, it is necessary to increase the flow rate ratio of the constant flow pump used to continuously mix the plating solution and the pH indicator solution. However, it is practically difficult to keep the flow rate of the pump that supplies the indicator solution, which needs to be kept at a particularly minute flow rate, constant over a long period of time, and this causes errors.

（２）　　ｐＨ指示薬の溶液は、経時変化により劣化す
る恐れがある。その劣化の度合が誤差を生じる原因とな
る。(2) The pH indicator solution may deteriorate over time. The degree of deterioration causes errors.

（３）被検液であるめっき液自身が色をもつ場合が多い
。そのような場合、めっき液の色が、測定波長の吸光度
を変化させる原因となる。(3) The plating solution itself, which is the test solution, often has a color. In such a case, the color of the plating solution causes a change in the absorbance at the measurement wavelength.

本発明にあっては、これらの誤差を、−指示薬の溶液の
等吸収点における吸光度及び被検液であるめっき液の吸
光度を測定し、その測定値を使用して補正することによ
り、正確な水素イオン濃度を求める・ものである。In the present invention, these errors can be corrected by measuring the absorbance at the isosbestic point of the indicator solution and the absorbance of the plating solution, which is the test solution, and correcting them using the measured values. This is to find the hydrogen ion concentration.

多くの岨指示薬には、吸光度が水素イオン濃度に依存し
ない等吸収点がある。たとえば、第１図は、ｍ−クレゾ
ールパープルの吸光スペクトルをて゛ 示すものがあるが、■の５２５　ｎｍでは吸光度が水素
イオン濃度により大きく変化するが、■の４７８０ｍで
は水素イオン濃度による吸光度の変化は全くない。同様
に、ｐＨ１，２−２，８で５４３ｎｍの吸光チ 度が変化する鳳モールブルーは４８５　ｎｍに、…１．
４〜２，６で５２３　ｎｍの吸光度が変化するトロペオ
リンＯＯは４７０ｎｍに、それぞれ等吸収点をもってい
る。そして、これらの…指示薬の溶液の水素イオン濃度
に依存する波長及び等吸収点における吸光度は、…指示
薬の濃度に比例する。即ち、被検液であるめっき液と一
指示薬の溶液との混合比が変化しても、その混合比の変
化は、等吸収点における吸光度の変化として現われる。Many indicators have an isosbestic point where absorbance does not depend on hydrogen ion concentration. For example, Figure 1 shows the absorption spectrum of m-cresol purple. At 525 nm (■), the absorbance changes greatly depending on the hydrogen ion concentration, but at 4780 m (■), the absorbance does not change due to the hydrogen ion concentration. Not at all. Similarly, Otori Mohr Blue, whose absorbance at 543 nm changes at pH 1, 2-2, 8, changes to 485 nm,...1.
Tropeolin OO, whose absorbance at 523 nm changes from 4 to 2,6, has an isosbestic point at 470 nm. The wavelength and the absorbance at the isosbestic point, which depend on the hydrogen ion concentration of the solution of these indicators, are proportional to the concentration of the indicator. That is, even if the mixing ratio of the plating solution, which is the test solution, and the solution of one indicator changes, the change in the mixing ratio appears as a change in absorbance at the isosbestic point.

従って、混合比の変化に起因する誤差は、等吸収点にお
ける吸光度の変化により補正することができる。また、
…指示薬の溶液は経時変化により変質することもあるが
、この場合も、経時変化の度合が等吸収点における吸光
度の変化として現われる。従って、この経時変化に起因
する誤差も、等吸収点における吸光度の変化により補正
することができる。Therefore, errors caused by changes in the mixing ratio can be corrected by changes in absorbance at the isosbestic point. Also,
...An indicator solution may change in quality over time, but in this case as well, the degree of change over time appears as a change in absorbance at the isosbestic point. Therefore, the error caused by this change over time can also be corrected by changing the absorbance at the isosbestic point.

一方、被検液であるめっき液は、それ自体の色をもつ場
合が多い。この影響を抑えるため、めっき液成分による
吸収が少ない波長で測定することが可能な…指示薬を選
択する必要がある。しかし。On the other hand, the plating solution that is the test solution often has its own color. To suppress this effect, it is necessary to select an indicator that can be measured at a wavelength that is less absorbed by the plating solution components. but.

このめっき液内体の色による影響を完全に無くすことは
困難である。また、めっき液内体の吸光度が、その成分
濃度の外に水素イオン濃度によっても変化する場合には
、めっき液内体の色による影響は大となる。そこで、こ
のめっき液内体の色による影響に起因する誤差を補正す
る必要が生じる本発明の実施態様にあっては、この補正
を、岨指示薬の溶液を添加した場合と添加しない場合の
めつき液の吸光度を時間分割して測定することにより行
った。It is difficult to completely eliminate the influence of the color of the plating solution. Furthermore, if the absorbance of the plating solution varies depending on the hydrogen ion concentration as well as the component concentration, the color of the plating solution will have a large effect. Therefore, in embodiments of the present invention in which it is necessary to correct errors caused by the influence of the color of the plating solution, this correction can be applied to the plating with and without the addition of the indicator solution. This was done by measuring the absorbance of the liquid over time.

次に、添付図面を使用して本発明の詳細な説明する。Next, the present invention will be described in detail using the accompanying drawings.

第２図は、本発明の実施例で使用した装置の一例を示す
。被検液であるめっき液は、供給源ｌから吸込まれ、ポ
ンプ２を介して混合器６に送り込まれる。これとは別に
、貯槽３の岨指示薬の溶液（ｍ−クレゾールパープル０
．２１／Ｉの水溶液）を、ポンプ４及び電磁弁５を介し
て、混合器６に送り込む。ポンプ２とポンプ４との流量
比は、２０：１であり、…指示薬の溶液を添加しても被
検液であるめっき液の水素イオン濃度変化は無視できる
程度である。電磁弁５は、処理装置１６からの信号に基
づき、ポンプ４からのｐＨ指示薬の溶液を混合器６に送
る、あるいは貯槽３に戻す操作を周期的に切り換える。FIG. 2 shows an example of the apparatus used in the embodiment of the present invention. A plating solution, which is a test solution, is sucked from a supply source 1 and sent to a mixer 6 via a pump 2. Separately, the solution of the indicator in storage tank 3 (m-cresol purple 0
．． 21/I aqueous solution) is fed into a mixer 6 via a pump 4 and a solenoid valve 5. The flow rate ratio between pump 2 and pump 4 is 20:1, and even if an indicator solution is added, the change in the hydrogen ion concentration of the plating solution, which is the test solution, is negligible. The solenoid valve 5 periodically switches between sending the pH indicator solution from the pump 4 to the mixer 6 or returning it to the storage tank 3 based on a signal from the processing device 16 .

混合器６を経た被検液は、吸光度測定セルフに送られ、
光源８からの光を吸収する。The test liquid that has passed through the mixer 6 is sent to the absorbance measuring device.
Absorbs light from light source 8.

吸光度測定セルフからの光は、その一部がハーフミラ−
９を透過し、残りがハーフミラ−９で反射され、それぞ
れ干渉フィルター１０及び１１を通過して検出器１２及
び１３に至る。干渉フィルター１０及び１１は、それぞ
れ５２５　ｎｍ及び４７８ｎｍ用のものであり、水素イ
オン濃度に依存する波長及び等吸収点にあたる波長の光
のみを透過させる。検出器１２及び１３からの電気信号
は、それぞれ変換器１４及び１５で吸光度に変換され、
処理装置１６に入力される。処理装置１６は、電磁弁５
の切換信号を出してから検出器の信号が安定するまでの
一定時間（約１〜２分）が経過した後、指示薬を添加し
た場合と添加しない場合について被検液の５２５ｎｍ及
び４７８ｎｍにおける吸光度を読み取る。指示薬を添加
した場合の三波長における吸光度をそれぞれＡ、□及び
Ａ４７　Ｂとし、添加しない場合のそれらをＢ、□及び
Ｒ４？ｌとすると、まず、（Ａｌｌ！Ｉ　−Ｂｓｔｓ　
）及び（Ａ４）♂−Ｂ４ｔｓ　）を計算し、被検液自体
の吸光に起因する誤差を補正する。次いで、■指示薬の
含有量が変化したことに起因する誤差を補正するために
、（Ａｓ２５−　Ｂｓｔｓ　）と（Ａ４７８−　Ｂ４ｙ
ｓ）との比を計算し、あらかじめ設定されている水素イ
オン濃度換算式に代入して水素イオン濃度を求める。Part of the light from the absorbance measurement self is a half mirror.
9, the remainder is reflected by half mirror 9, passes through interference filters 10 and 11, and reaches detectors 12 and 13, respectively. The interference filters 10 and 11 are for 525 nm and 478 nm, respectively, and transmit only light having a wavelength that depends on the hydrogen ion concentration and a wavelength corresponding to the isosbestic point. The electrical signals from detectors 12 and 13 are converted to absorbance by converters 14 and 15, respectively;
It is input to the processing device 16. The processing device 16 includes a solenoid valve 5
After a certain period of time (approximately 1 to 2 minutes) has elapsed from issuing the switching signal until the detector signal stabilizes, measure the absorbance of the test solution at 525 nm and 478 nm with and without the addition of an indicator. read. The absorbances at three wavelengths when an indicator is added are A, □, and A47 B, respectively, and those when no indicator is added are B, □, and R4? First, (All!I −Bsts
) and (A4)♂-B4ts) are calculated, and errors due to light absorption of the test liquid itself are corrected. Next, (As25- Bsts ) and (A478- B4y
s) is calculated and substituted into a preset hydrogen ion concentration conversion formula to determine the hydrogen ion concentration.

第３図は、水素イオン濃度換算式を求めるための関係線
を示したものであり、横軸は−、縦軸は５２５　ｎｍと
４７８　ｎｍの吸光度比を表わす。FIG. 3 shows a relationship line for determining the hydrogen ion concentration conversion formula, where the horizontal axis represents - and the vertical axis represents the absorbance ratio between 525 nm and 478 nm.

このようにして、めっき液の水素イオン濃度を求める。In this way, the hydrogen ion concentration of the plating solution is determined.

その測定精度は、他に比較できる水素イオン＃度測定手
段がない程優れたものであり、例えば、同一の被検液を
測定日を変えて測定した場合、その誤差が±０．０１ｐ
Ｈ以下の範囲にある。Its measurement accuracy is so excellent that there is no other comparable hydrogen ion measurement method; for example, when the same test liquid is measured on different measurement days, the error is ±0.01p.
It is in the range below H.

【図面の簡単な説明】 第１図は、ｍ−クレゾールパープルの吸光スペクトルを
示し、第２図は、本発明の実施例において使用した装置
の一例を示し、第３図は、水素イオン濃度と吸光度比と
の関係を示す。 １・・・めっき液供給源　　　２・・・ポンプ３・・・
…指示薬浴液貯槽　　４・・・ポンプ５・・・電磁弁　
　　　　　６・・・混合器７・・・吸光度測定セル　　
　８・・・光源９・・・ハーフミラ−１０及び１１・・
・干渉フィルター１２及び１３・・・検出器　　　　１
４及び１５・・・変換器１６・・・処理装置 代理人　弁理士　佐々木　俊　哲 （９）　　　　　　　　−２３３−[Brief Description of the Drawings] Figure 1 shows the absorption spectrum of m-cresol purple, Figure 2 shows an example of the apparatus used in the examples of the present invention, and Figure 3 shows the hydrogen ion concentration and The relationship with absorbance ratio is shown. 1... Plating solution supply source 2... Pump 3...
...Indicator bath liquid storage tank 4...Pump 5...Solenoid valve
6... Mixer 7... Absorbance measurement cell
8...Light source 9...Half mirror 10 and 11...
・Interference filters 12 and 13...detector 1
4 and 15...Converter 16...Processing device agent Patent attorney Shun Tetsu Sasaki (9) -233-

Claims (2)

【特許請求の範囲】[Claims] （１）電気めっき液に添加する一指示薬の溶液の等吸収
点における吸光度を測定し、その測定結果を使用して一
指示薬の＃液の流量変化及び劣化に起因する誤差を補正
することを特徴とする電気めっき液の水素イオン濃度測
定方法。(1) The absorbance at the isosbestic point of a solution of one indicator added to the electroplating solution is measured, and the measurement results are used to correct errors caused by flow rate changes and deterioration of solution # of one indicator. Method for measuring hydrogen ion concentration in electroplating solution. （２）　　ｐＨ指示薬の溶液を添加した場合と、添加し
ない場合とのめつき液の吸光度をそれぞれ時間分割して
測定し、その測定結果を使用してめっき液口体の色に起
因する誤差を補正する特許請求の範囲第１項記載の方法
。(2) Measure the absorbance of the plating solution with and without the addition of a pH indicator solution over time, and use the measurement results to eliminate errors caused by the color of the plating solution. The method according to claim 1 to be amended.
JP21462282A 1982-12-09 1982-12-09 Measurement of hydrogen ion concentration of electroplating bath Pending JPS59105545A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP21462282A JPS59105545A (en) 1982-12-09 1982-12-09 Measurement of hydrogen ion concentration of electroplating bath

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP21462282A JPS59105545A (en) 1982-12-09 1982-12-09 Measurement of hydrogen ion concentration of electroplating bath

Publications (1)

Publication Number Publication Date
JPS59105545A true JPS59105545A (en) 1984-06-18

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JP21462282A Pending JPS59105545A (en) 1982-12-09 1982-12-09 Measurement of hydrogen ion concentration of electroplating bath

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6152274A (en) * 1984-08-20 1986-03-14 Shimadzu Corp Cell culture apparatus
JP2007163350A (en) * 2005-12-15 2007-06-28 Nikon Corp Observation device
KR20130141567A (en) * 2011-04-27 2013-12-26 날코 컴파니 Method and apparatus for determination of system parameters for reducing crude unit corrosion
JP2013545988A (en) * 2010-12-01 2013-12-26 ナルコ カンパニー Method and apparatus for system parameter determination to reduce crude equipment corrosion

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6152274A (en) * 1984-08-20 1986-03-14 Shimadzu Corp Cell culture apparatus
JP2007163350A (en) * 2005-12-15 2007-06-28 Nikon Corp Observation device
JP2013545988A (en) * 2010-12-01 2013-12-26 ナルコ カンパニー Method and apparatus for system parameter determination to reduce crude equipment corrosion
KR20130141569A (en) * 2010-12-01 2013-12-26 날코 컴파니 Method and apparatus for determination of system parameters for reducing crude unit corrosion
US9453798B2 (en) 2010-12-01 2016-09-27 Nalco Company Method for determination of system parameters for reducing crude unit corrosion
KR20130141567A (en) * 2011-04-27 2013-12-26 날코 컴파니 Method and apparatus for determination of system parameters for reducing crude unit corrosion
JP2014514575A (en) * 2011-04-27 2014-06-19 ナルコ カンパニー System parameter determination method and apparatus for reducing corrosion of crude equipment

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