JP2002047575A - Automatic analyser and controller of electroless composite plating liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily, reliably and automatically analyze the metal ion concentration in an electroless composite plating liquid. SOLUTION: This automatic analyzer and controller for automatically analyzing the electroless composite plating liquid, and automatically controlling the plating liquid in an appropriate composition and/or use condition comprises a mechanism for measuring the transmissivity or the absorbance by at least two different wavelengths after the plating liquid is automatically introduced in an analysis cell for a method of measuring the concentration in the plating liquid of the metal component in the plating liquid by an absorptiometry and a mechanism for calculating the intended concentration from the measured value by an arithmetic operation, and displaying the result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for automatically analyzing and managing an electroless composite plating solution.

[0002]

2. Description of the Related Art The requirements for plating quality are increasing year by year, and proper management of plating solutions is a heavy burden on production sites. On the other hand, costs associated with price competition are high. As a part of the reduction efforts, the automation of the plating process is progressing, and as a result, an automatic plating solution management device is becoming indispensable.

Particularly in the recent plating industry, the demand for electroless plating, particularly electroless nickel plating, is very high.
Although used for a wide range of applications, this electroless plating requires a very high analysis frequency compared to electroplating, and at the same time replenishment frequency is extremely high. Developed and put into practical use. And it has already penetrated a wide range of users as an important element of electroless plating equipment.

[0004] The content of the above-mentioned apparatus is described in "Automatic Management of Plating Bath" (Surface Technology, Vol. 34, No. 6, 19).
83) and "Automatic Management of Electroless Plating Bath" (Practical Surface Technology, Vol. 31, No. 10, 1984).

[0005] Various components are blended in the plating solution. As components to be analyzed by the automatic solution management device, for example,
It is often the case that only very limited components such as components for replenishment and components most important for ensuring plating quality are analyzed, and it can be said that there is no analysis of all components.

[0006] If the automatic liquid management device does not analyze, but there is a component that needs to be analyzed periodically, a manual analysis is performed and adjustment is performed if necessary. In reality, most components are not analyzed or controlled at all.

Specifically, in the automatic liquid management system for the electroless nickel plating solution, the analyzed components are often two components of Ni concentration and pH. In particular, in the electroless nickel plating, the management of the Ni concentration is the most important. When the electroless nickel plating is performed, the Ni component is consumed and the concentration gradually decreases. Therefore, the Ni component is sequentially replenished to maintain the Ni concentration at a predetermined value. It is a general liquid management means to use the components of the formula (1) proportionally. In other words, the Ni concentration is used as a standard for ideally managing all components, and it can be said that the analysis accuracy of the Ni concentration in liquid management is very important.

As a method of analyzing the Ni concentration, a chelate titration method and an absorption spectrometry are generally used. At present, however, the absorption spectrometry has been popularized in an automatic liquid management apparatus for electroless nickel plating. Absorption spectroscopy has historically been very old as a means of composition analysis by instrumental analysis. There are various methods up to the spectrophotometric method of measuring the absorbance using the method. The principle and analysis method are described in "Guidebook for Instrumental Analysis" (edited by The Japan Society for Analytical Chemistry, published by Maruzen Co., Ltd., July 10, 1996) and "Experiment and Calculation of Quantitative Analysis" (by Seiji Takagi) , Published by Kyoritsu Shuppan Co., Ltd., first edition, November 5, 1961). Specifically, when quantitatively analyzing the Ni concentration in the electroless nickel plating solution by an absorption spectrometry, the degree of light absorption at a green wavelength in the visible light region is measured.

The electroless nickel plating solution contains various complexing agents. The Ni component exists as Ni complex ions, and the Ni complex strongly absorbs light in the green wavelength range. There is a good proportional relationship between the absorbance and the Ni concentration. Utilizing this feature, quantitative analysis is performed with high accuracy. In order to perform measurement in a specific wavelength range, it is necessary to split light, but many apparatuses employ a method of selecting light with an interference filter. In addition, there is a method to obtain a wavelength very close to monochromatic light by using a monochromator using a diffraction grating or a prism, etc., but it is mechanically complicated and relatively expensive. Since the analysis accuracy of the Ni concentration required for the apparatus does not require a high degree of spectroscopy, it is hardly used.

[0010] There are many cases in which absorption spectroscopy is used as an automatic liquid management device or liquid analysis method without being limited to electroless plating, and many applications have been found in patent searches. However, there are almost no proposals regarding a method of measuring an electroless composite plating solution in an automatic liquid management device.

As described above, the automatic liquid management device for the electroless plating solution has already been put to practical use and spread, but when the existing solution management device is diverted for the purpose of managing the electroless composite plating solution, Various problems occur. First, in the case of an electroless nickel plating solution, existing devices often use an absorption spectroscopy method for measuring the Ni concentration. At that time, the wavelength of the light to be measured is measured at a wavelength at which light absorption caused by the Ni complex is absorbed. Most of them are measured by one wavelength in the visible light region (VIS, wavelength range of 400 to 750 nm).

However, when measuring the composite plating solution, the incident light includes not only light that travels straight and is transmitted and absorbed, but also light that is reflected by suspended particles and light that is diffracted and scattered. I do. The reflected light, diffracted and scattered light by these suspended particles is apparently a decrease in transmitted light, and cannot be distinguished from a decrease in transmitted light due to absorption by the target component, and as a result, a large amount of the target component is present. Misunderstood.
Further, the degree of influence of the suspended particles varies depending on the type, particle size distribution, concentration, etc. of the suspended particles, and may also vary depending on various factors of the plating solution. For example, when a plating solution is specified, the effect of suspended particles is relatively stable, so that a constant value is expected as a decrease in transmittance due to turbidity, so that component concentrations can be measured relatively accurately. It is possible. However, since the composition of the electroless plating solution changes greatly when it is used, it is necessary to correct the effect, and there is a limit in considering the effect of turbidity at a constant value.

In addition, when a specific defect occurs, for example, when fine particles cause a poor dispersion due to a specific dive component, the turbidity significantly changes and a large error occurs in the analysis result of the target component. Also, as a similar problem, when a situation occurs in which the plating solution sampling mechanism is malfunctioning and a plating solution in which fine particles are uniformly dispersed cannot be collected.
There is a concern that serious and fatal analysis errors may occur.

It can be said that it is substantially impossible to secure the required accuracy and reliability by using the analysis method of the conventional apparatus. As described above, there are several means for solving the problems in the analysis of the electroless composite plating solution, but each has a drawback.

For example, a method of measuring fine particles dispersed in a plating solution after separating them by filtration, sedimentation, or centrifugal separation involves difficulties and cost disadvantages in a mechanism for performing the separation continuously or intermittently. In addition, since the plating solution is wasted in the analysis, the solution adjustment becomes considerably difficult. In addition, there is a method in which the analysis is performed by a chelate titration method. However, the apparatus is considerably complicated, and in addition, a highly accurate and highly reliable sampling apparatus is required to secure the accuracy. In addition, there are considerably more negative factors compared with the absorption spectrometry, such as the generation of a large amount of waste liquid due to analysis, and the need for analytical consumables such as indicators and titrants.

The plating solution can be processed for analysis like a conventional general electroless plating solution automatic analysis and management device.
It can be said that an ideal method is to use a circulation cycle in which measurement is performed as it is without wasting as much as possible and the measurement is returned to the plating tank.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is directed to a method for analyzing the concentration of Ni in an electroless composite plating solution, particularly an electroless composite nickel plating solution, using a fluororesin (PTFE, FEP, PFA, TFE oligomer). Fluorinated graphite (CF _x ), graphite, alumina (Al ₂ O ₃ ), silicon carbide (SiC), boron nitride (B
N) solves the problem of reduced analysis accuracy due to the presence of suspended particles, and can secure practically sufficient analysis accuracy, and also automatically analyzes and manages inexpensive electroless composite plating solutions It is intended to provide a device.

[0018]

According to the present invention, in order to achieve the above object, fine particles such as fluorine resin fine particles, graphite fluoride, graphite, alumina, silicon carbide, and boron nitride are dispersed in an electroless plating solution. In the automatic analysis and management device that automatically analyzes the electroless composite plating solution that has been made and further replenishes and adjusts the solution automatically based on the analysis result,
It provides various methods on the analysis method and apparatus to ensure the necessary analysis accuracy, and as described above, for quantitatively analyzing the concentration of precipitated metal ions in the electroless composite plating solution by an absorption spectrophotometric method. The main obstacle is the turbidity of the fine particles dispersed in the plating solution for eutectoid deposition. As a method to solve this problem, absorbance is measured at two or more characteristic measurement wavelengths, and the obtained value is calculated using simultaneous equations to derive the target deposited metal ion concentration with the required accuracy. In developing an automatic analyzer / management device based on this method, there were various problems that caused measurement errors.
As a result, it has been found that the problem can be solved by devising a characteristic plating solution sampling mechanism, a measuring condition, an operating condition of the apparatus, and the like, and the present invention has been accomplished.

Therefore, the present invention provides the following automatic analyzer and controller for electroless composite plating solution. Claim 1: In an apparatus for automatically analyzing an electroless composite plating solution and automatically managing to an appropriate solution composition and / or use conditions,
As a method of measuring the concentration of the metal component in the plating solution by the absorption spectrophotometry, a mechanism for automatically measuring the transmittance or the absorbance at at least two or more different wavelengths after automatically introducing the plating solution into the analysis cell. A mechanism for calculating a target concentration from the measured value by arithmetic processing and displaying the result, and an automatic analysis and management device for the electroless composite plating solution. In another embodiment, at least one of the measured wavelengths has a half width of 1.
2. The automatic analysis / management apparatus according to claim 1, wherein the spectrum is separated to a wavelength of 100 nm or less. Claim 3: The combination of measurement wavelengths is at least one measurement wavelength of 250 to 350 nm or 450 to 550.
2. A combination in which a wavelength range of nm is selected and a wavelength range of 350 to 450 nm or 550 to 800 nm is selected as at least one measurement wavelength as another measurement wavelength not overlapping with this wavelength. Or the automatic analysis / management device according to 2. Claim 4: After the plating solution is automatically introduced into the analysis cell,
4. The automatic analysis / management apparatus according to claim 1, wherein the measurement timetable is set so as to secure a standing time of 15 seconds or more before starting measurement of transmittance or absorbance. . Claim 5: Periodically introducing pure water into the analysis cell to wash the inside of the analysis cell, and measuring transmittance or absorbance at a measurement wavelength set in a state where the cell is filled with the pure water. It has a function to perform these measurements, and then compares these measured values with 100% transmittance or zero absorbance with respect to the measured values of the transmittance or absorbance of the plating solution performed within the time until the same measurement with pure water is performed thereafter. The automatic analysis / management apparatus according to claim 1, wherein the automatic analysis / management apparatus is used as a reference value. In a sixth aspect of the present invention, there is provided a vertically long plating solution retaining portion having a cross-sectional area twice or more as large as the cross-sectional area of the sampling pipe in a sampling path for introducing the plating solution into the analysis cell, and the plating solution retaining portion. A trap mechanism for preventing fine bubbles embodied in the plating solution from being brought into the analysis cell by providing an inlet at an upper portion and an outlet at a lower portion. 6. The automatic analysis / management apparatus according to any one of items 5 to 5. In a preferred embodiment, the electroless composite plating solution is an electroless composite nickel plating solution, and the nickel component in the plating solution is measured.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The apparatus for automatically analyzing and controlling an electroless composite plating solution according to the present invention is a method for automatically measuring the concentration of a metal component in a plating solution by an absorption spectrophotometry. After introducing into the analysis cell, a mechanism for measuring the transmittance or absorbance at at least two or more different wavelengths, and a mechanism for calculating the target concentration from the measured value by arithmetic processing and displaying the result Is what it is.

The electroless composite plating solution to which the present invention is applied is a dispersion of water-insoluble composite material particles in the electroless plating solution, and the electroless plating solution is sodium hypophosphite. , An electroless nickel plating solution using a boron-based reducing agent such as dimethylamine borane as a reducing agent,
Examples include an electroless nickel-cobalt plating solution, an electroless cobalt plating solution, and an electroless copper plating solution. Further, as a composite material, a fluororesin (PTFE, F
Examples thereof include EP, PFA, and TFE oligomers), graphite fluoride (CF _x ), graphite, alumina (Al ₂ O ₃ ), silicon carbide (SiC), and boron nitride (BN). As such an electroless composite plating solution, those having a known composition and a commercially available bath can be used.

In this case, the present invention is particularly suitably employed for measuring the nickel component in the electroless composite nickel plating solution. Here, the composition of the electroless composite nickel plating solution to be subjected to the measurement is not limited. For example, the Ni ion concentration is 1 to 10 g / L, particularly 3 to 7 g / L.
Those containing 30 g / L or less, especially 10 g / L or less of composite material particles such as L and fluororesin are preferably used. In addition, the lower limit of the content of the composite material particles is not particularly limited, but is usually 0.5 g / L or more, particularly 1 g / L or more.
The reducing agent is preferably a hypophosphite such as sodium hypophosphite, the concentration of which is 5 to 50 g / L, particularly 10 to 30 g / L. Phosphites, such as sodium phosphite, generated by oxidation of
The method of the present invention can be effectively applied to the electroless composite nickel plating solution accumulated in a wide range of 0 g / L. The pH of the electroless composite nickel plating solution is usually 3 to 9, particularly 4 to 8.

In the present invention, when analyzing a metal component in the electroless composite plating solution, for example, a Ni component in the case of an electroless composite nickel plating solution, transmittance or absorbance at two or more different wavelengths is analyzed. Is measured. That is,
In the case of an electroless composite nickel plating solution, measurement is performed at a wavelength (for example, 660 nm) for measuring the Ni concentration and a wavelength within a specific range (for example, 520 nm) of a shorter wavelength region as the wavelength of the light for measuring the absorbance. Is adopted.

Hereinafter, sodium hypophosphite is used as a reducing agent, and polytetrafluoroethylene (P
A method of measuring at two or more wavelengths and its effect will be described by taking a non-electrolytic composite nickel plating solution (TFE) particles using electroless (Ni-P / PTFE composite plating solution) as a representative example.

FIGS. 1 to 3 show electroless Ni-P / PTFE having a trade name of "Nimflon" commercially available from Uemura Kogyo KK as an electroless Ni-P / PTFE composite plating solution.
This is a representative example of an absorption pattern obtained when a sample solution in which the Ni concentration or the PTFE concentration is intentionally changed using a composite plating chemical is measured and measured by an absorptiometry.

In FIG. 1, the Ni concentration of the plating solution without adding a slurry of PTFE solution (solid content: about 66 wt%) called “Nimflon F”, which is a chemical for giving PTFE particles to the plating solution, is gradually increased. 9 is a summary of the absorption patterns obtained with the plating solution changed to.
Here, 350-450 n with increasing Ni concentration.
m and the absorbance are proportionally increased in the wavelength range of 550 to 800 nm.

On the other hand, FIG. 2 shows the case where the Ni concentration is 0 g / L.
It is a compilation of absorption patterns obtained with a plating solution in which Nimflon F (a slurry-like PTFE solution) is stepwise changed in concentration. Absorbance increases proportionately in all wavelength ranges measured with increasing PTFE concentration, and the characteristic feature is that the increasing tendency of absorbance increases at shorter wavelengths.

FIG. 3 shows a case in which Nimflon F (slurry PTFE) is used as in FIG.
2) is a collection of absorption patterns obtained with a plating solution in which the solution is changed stepwise. As seen in FIG.
Absorptions of 350 to 450 nm and 550 to 80
Although the absorbance is observed in the wavelength range of 0 nm, the absorbance is proportionally increased in all the wavelength ranges measured with the increase of the PTFE concentration, and a characteristic tendency that the absorbance is acceleratedly increased as the wavelength becomes shorter is also observed. Was.

The absorption pattern shown in FIG.
It can be understood as an absorption pattern obtained by adding the absorption pattern as shown in FIG. 2 with the PTFE concentration change to the absorption pattern of the / L electroless plating solution. In order to grasp this more accurately, for example, 400 nm and 520 n
4 to 7 summarize the absorbance measured at m in relation to the Ni concentration or Nimflon F concentration (or PTFE concentration). As a result, the change in absorbance has a very good proportional relationship to both the Ni concentration and the PTFE concentration, and the so-called absorbance at any Ni concentration and particle concentration is determined by the metal ion concentration in the plating solution and the turbidity due to the dispersed particles. It was confirmed that it could be understood as the sum of From this, it was suggested that if measurement (calibration curve creation) for grasping both characteristics was performed in advance, the adverse effect of turbidity could be avoided and the target Ni concentration could be measured. .

However, in the electroless composite plating, the concentration of the dispersed particles and the turbidity thereof vary depending on factors other than the preset conditions, for example, various factors such as the use of a plating solution and sampling conditions. Unless it is grasped at any time with a certain degree of accuracy and reflected in the arithmetic processing, an error increases. As a method of the present invention, two unknown values, Ni concentration and turbidity derived from the presence of dispersed particles, are derived by solving simultaneous equations based on the results measured under two or more wavelength conditions. A method that is the basis for

Then, using the measurement results of FIGS. 1 to 7, a calibration curve was prepared by combining various measurement wavelengths, and the degree of occurrence of an error when an arbitrary plating solution was assumed was examined. As a result, as a combination capable of calculating the Ni concentration with the required accuracy with respect to the fluctuation of the Ni concentration and the fluctuation of the turbidity, first, as a method of measuring at two measurement wavelengths, the first wavelength is Ni 350-450 with absorption
measurement at any wavelength in the wavelength range of 370-430 nm or 600-770 nm, more preferably 390-410 nm or 640-740 nm, and the first wavelength overlaps with the first wavelength. 250 to 350 nm or 450 as the second wavelength
550 nm, more preferably 275-33.
5 nm or 480-535 nm, most preferably 300
It has been found that combining measurement at an arbitrary wavelength within the wavelength range of ３２０320 nm or 500-535 nm is a combination of wavelengths that can reduce the occurrence of errors.

Here, in the present invention, the concentration of metal ions, for example, nickel ions, of the electroless composite plating solution is kept constant, and a plurality of composite materials, for example, PTFE having different PTFE concentrations (preferably 3 or more, more preferably 4 types) are used. the plating solution described above), and absorbance a ₁ of the first wavelength WL ₁ second wavelength WL
₂ of absorbance A ₂ were measured to determine the following relationship from the relationship between the absorbance A ₁ and A ₂ (It is assumed that A _1> A _2). y = αx + β x: Absorbance at the first wavelength y: Absorbance at the second wavelength α, β: Coefficient

On the other hand, a plurality of types (preferably three or more, more preferably six or more) in which the concentration of metal ions, for example, nickel ions, of the electroless composite plating solution is changed and the concentration of composite materials, for example, PTFE, are also variously changed. Similarly, the absorbances A ₁ and A ₂ are measured for the plating solution of, and the following relational expression is obtained from the relation between the K value and the metal ion concentration. M = γK−δ M: Metal ion concentration K: Absorbance at the first wavelength−α × Absorbance at the second wavelength γ, δ: Coefficient

From the relational expression between the K value and the metal ion concentration thus obtained, the metal ion concentration is determined by measuring the absorbance at the first and second wavelengths.

In the case of an alloy-based composite plating solution, the first
By previously calculating a relational expression in which a second metal ion to be alloyed with this metal ion is added to these metal ions, the concentration of these metal ions can be obtained. For example, the third wavelength can be set, and can be obtained as a relational expression in which the influence on the absorbance by the second metal ion is added.

In the case of a composite plating solution of copper or cobalt, as in the case of nickel, by appropriately selecting a wavelength that absorbs copper or cobalt and a wavelength that does not absorb copper or cobalt, the metal ion The concentration can be analyzed with high accuracy. In the case of copper, conversion to bivalent copper ions is preferred.

Further, when the device is actually put into practical use, spectroscopy is required for measuring at a specific wavelength, and the use of an interference filter as the method can provide the most inexpensive and simple device structure. . However, in the method of performing spectroscopy using an interference filter, the spectral accuracy becomes a problem, and the spectrally separated light has a certain wavelength range. This is expressed as the half width of the wavelength of the interference filter, and is one of the qualities. Since a filter having a smaller half width is more expensive, it is important to select an interference filter having a relatively wide half width in order to provide an inexpensive device. Therefore, to put the present invention into practical use, the extent to which the half-value width affects the quality of the interference filter necessary to secure sufficient analysis accuracy was also examined.
As a result, assuming an interference filter having a center value at an arbitrary wavelength in the most preferable wavelength range among the two measurement wavelength ranges described above, an analysis error may be acceptable if the half width is 100 nm or less. It has been found that the half width is preferably 50 nm or less, and most preferably 20 nm or less.

Further, during the demonstration test using the absorbance measurement unit of the apparatus described later, when an interference filter having an extremely narrow half-width of less than 1 nm was used, a sufficient amount of light could not be secured. This measure inevitably involves costs such as an increase in the performance of the light-receiving unit and an increase in the amount of light from the light source. It became clear that it became. The lower limit of the half width is suitably 1 nm or more, more preferably 5n.
m, most preferably 10 nm or more.

Next, an example of the apparatus of the present invention will be described with reference to FIGS.

In FIGS. 8 and 9, A is a control unit for performing arithmetic processing and various operation instructions, and B is a concentration measurement unit. The analysis value of the electroless composite plating solution measured by this measurement unit B is used for the control unit. A, the analysis value is calculated, and a predetermined operation instruction corresponding to the analysis value is given to the plating apparatus.

The control section A has a built-in computer, which performs arithmetic processing and various operation instructions as described above, and also has a display mechanism for displaying the analysis results and the operation status of the apparatus as needed. In addition, the control condition setting including the setting of the operation condition of the apparatus and the manual operation can be performed in this portion. Furthermore, if a personal computer is connected to this control unit via a communication port, it is possible to perform all main control such as data processing of analysis results and operation instructions from the operating environment using a dedicated software. A communication line or the like for controlling a plurality of units and communication with a temperature controller for controlling the plating temperature at the same time can also be connected.

The measuring section B has an absorbance measuring unit 10 and a pH cell 12, as shown in FIG. p
The pipe to the H cell 12 has an inner diameter of 3 mm, and the pH cell 1
2 has an inner diameter of 14 mm. The pH cell 12 is connected to a column 14 for supplying and storing a saturated solution of KCl, and has a temperature sensor 16. The inner diameter of the tube that is piped from a certain location of the temperature sensor 16 without passing through the absorbance cell 10a is larger than the inner diameter of the tube to the absorbance cell 10a, and the plating solution containing bubbles is less likely to flow to the absorbance cell 10a. ing. Although not shown, the absorbance measurement unit 10 has a light receiving portion on one side of the absorbance cell 10a, and a secondary diaphragm, an interference filter, a primary diaphragm, a light source lamp on the opposite side in order from the cell 10a side. In addition, two filters are fixed in a fan shape from the axis of the low-speed motor with the axis as short as possible so that the two types of interference filters can be automatically and accurately switched automatically. It is arranged in a state, and has a mechanism in which one of the filters is moved to a predetermined position in the optical path and stopped by the forward and reverse rotation of the motor.

In FIG. 9, reference numeral 18 denotes a sampling pump, and V1 to V8 denote solenoid valves, respectively. The solenoid valves are a pure water supply unit for V1, a first sample supply unit for V2, and a first sample supply unit for V3. A two-sample supply unit, a pH4 standard solution supply unit is connected to V4, a pH7 standard solution supply unit is connected to V5, and a solenoid valve V6 is connected to a drain.
V7 is connected to the first sample discharging unit, and V8 is connected to the second sample discharging unit. Then, the solenoid valve V1
To V5 and V6 to V8 are appropriately opened and closed, for example, V2, V7
Is opened, and the other is closed. When the sampling pump 18 is operated, the first sample passes through V2 from the first plating tank to p.
It flows into and circulates into the H cell 12, measures the pH of the first sample, flows into and circulates into the absorbance measuring unit 10, and circulates from V7 into the first plating tank. After stopping the sampling pump 18, the absorbance is measured at 660 nm, and then the interference filter of the absorbance unit 10 is switched to measure the absorbance at 520 nm. After the measurement of the absorbance is completed, V2 is closed and the sampling pump 18 is operated for a predetermined time.
The cell 12 flows into and flows into the absorbance measurement unit 10,
V7 is closed and V6 is opened to drain to drain. These operations are performed at appropriate intervals.

After the above analysis operation, calibration and cleaning are performed periodically. For the calibration of the pH electrode, after introducing the above KCL saturated solution, V4 is opened, the sampling pump 18 is operated, the pH4 standard solution is allowed to flow through the pH cell 12 and the absorbance measurement unit 10, and after draining to the drain, V4 is closed. V5
Is opened and the pH 7 standard solution is circulated and discharged in the same manner. Thereafter, the analysis operation is performed. Further, the cleaning step is performed in the above KC.
After the introduction of the L-saturated solution, V5 is closed, V1 is opened, and pure water flows into and flows through the pH cell 12, and the absorbance measurement unit 10
While flowing into the inside and letting it flow through the drain, the absorbance in pure water is measured for the two wavelengths in the same manner as described above.

Next, results of various verification tests performed using this apparatus will be described.

First, regarding the measurement wavelength, an automatic analysis and management apparatus of the past general electroless nickel plating solution often uses an arbitrary wavelength of 600 to 800 nm. The reason for this is that, in the performance of the light source and the light receiving unit, a wavelength having a relatively long visible light range tends to secure a sufficient amount of received light. Was selected. Furthermore,
The second measurement wavelength is set to 520 nm as in the previous basic study.
The wavelength which has almost no absorption due to the Ni concentration was selected, and the examination was conducted at these two measurement wavelengths.

First, the creation of a calibration curve in this apparatus is performed in the same manner as shown in FIGS.
The test was carried out for several types of electroless Ni-P / PTFE composite plating solutions. As an example, Table 1 and FIGS.
1. Further, the results of Nimflon FUL plating solutions (manufactured by Uemura Kogyo KK) having different base solution compositions are shown in Table 2 and FIGS.
Shown in

[0048]

[Table 1]

[0049]

[Table 2]

Here, FIGS. 10 and 12 show Nimflon and Nimflon FUL plating solutions, respectively.
FIG. 10 shows the relationship between the absorbance (ABS) at a wavelength of 660 nm and the absorbance (ABS) at a wavelength of 520 nm in the samples in which the concentration was constant and the PTFE concentration was changed (Sample Nos. 5 to 9). y = 0.7116x + 0.2338, R ² =
0.9964 FIG. 12: y = 0.765x + 0.2364, R ² =
0.9905 is given.

On the other hand, FIG. 11 and FIG. 9 shows the relationship between the K value and the Ni concentration in 1 to 9; In this case, the K value is: K value = ABS (660) −α × ABS (520) (However, ABS (660): absorbance at a wavelength of 660 nm, ABS (520): absorbance at a wavelength of 520 nm, α: the above figure) Coefficients of the relational expression x obtained from 10 and 12, ie, 0.7116 for Nimflon in FIG. 10 and 0.6765 for Nimflon FUL in FIG.
Therefore, from FIGS. 11 and 13, FIG. 11: Ni = 27.652 × [ABS (660) −
0.7116 × ABS (520)]-1.4267, R
² = 0.9989 FIG. 13: Ni = 22.857 × [ABS (660) −
0.6765 × ABS (520)] - 0.811, R 2
= 0.9983 is given.

The relational expressions obtained from FIGS.
In the case of Nimflon and Nimflon FUL, in a sample solution in which the Ni concentration and the PTFE concentration are actually unknown, respectively, two absorbances obtained when absorbance is measured at two measurement wavelengths, and an absorbance at 660 nm (ABS660)
This is an equation used as a calibration curve for obtaining the Ni concentration using the values of the absorbance at 520 nm (ABS 520). In the two types of electroless Ni-P / PTFE composite plating solutions exemplified here, the Ni concentration and the PT
There is a good proportional relationship with the FE concentration, and the difference between the Ni concentration derived from the final calculation formula and the value separately obtained by titration analysis is at most 0.04 g / L, which is extremely high accuracy and It was confirmed that it had become.

For reference, if a single wavelength, here 6 wavelengths, is used as in the case of a conventional general electroless plating apparatus.
When the Ni concentration is calculated from the absorbance measurement at 60 nm,
A simulation of how much error occurs due to the effect of turbidity indicated that there was a possibility that an error of about 0.8 g / L might occur at the maximum. A simple calculation using two measurement wavelengths shows that the analysis accuracy is improved by about 20 times, confirming that the effect is extremely high.

Next, a description will be given of the result of a test in which the electroless composite plating solution is actually automatically analyzed and managed using the above-described apparatus and the above relational expression. A typical example is Nimflon F which is an electroless Ni-P / PTFE composite plating.
Using a UL plating solution (the PTFE concentration was 4.0 g / L, and the PTFE content in the obtained electroless plating film was 25 vol%), Ni ions were continuously provided from the time of building bath. (Nickel sulfate), sodium hypophosphite, and PTFE to keep the concentration of these components almost constant, and to replenish sodium hydroxide to keep the pH almost constant, while keeping the MTO (turn number, 1 The turn indicates the time when 4.46 g of Ni ²⁺ is consumed or precipitated per liter of the plating bath, and is an index indicating the aging degree of the electroless nickel plating solution).
A concentration analysis was performed. The plating solution capacity was 50 L. The results are shown in Table 3 and FIGS. For example, FIG.
, The coefficient of x in the linear equation, ie, 0.1165
Divided by the Ni concentration standard value 4.5 (g / l) can be used as a one-turn correction coefficient, and 1+ (0.1165 ÷ 4.5) = 1.026 is calculated as Ni of the one-turn device. Ni after correcting the value multiplied by the concentration
Concentration.

[0055]

[Table 3]

Table 3 summarizes typical numerical values of the analysis results. FIG. 14 summarizes the results regarding the Ni concentration and FIG. 15 summarizes the results regarding the pH.
There was no significant error between the value obtained by manual analysis of the Ni concentration of the plating solution during running and the value indicated as no correction in the analysis of the above apparatus. However, as the running progressed, the error tended to increase to a level that could not be ignored. The cause is that the absorption degree caused by Ni complex ions gradually decreases due to the accumulation of phosphites and sulfates as aging accumulation components in the plating solution while the electroless composite nickel plating solution is used. This is the error that occurs. Contrary to the pattern exemplified here, there is also a type of electroless composite plating solution in which the degree of absorption gradually increases, but in that case, the complexing agent is supplied by replenishing the complexing agent to an extent exceeding the decrease in the degree of absorption due to aging accumulation. This is the type of electroless plating solution that is increasing, so if this part is a commercially available electroless plating solution, the habit of the plating solution should be grasped in advance and appropriate for the analysis value. This can be solved by making appropriate corrections. Nimflon F actually illustrated here
With the UL plating solution, if a certain correction is performed by adding a small addition to the proportional correction coefficient, a good accuracy is obtained in which the corrected value in FIG. 14 substantially overlaps the manual analysis value.

The calculation of the correction coefficient is as shown in FIG.
The Ni concentration standard value (for example, 4.5 g /
There is a proportional relationship in a graph plotting a value obtained by subtracting the error (i.e., the analysis value of the device without correction-the manual analysis value) from 1), and the correction coefficient can be derived from the linear equation.

On the other hand, p which is an important management item of the plating solution
Although a constant error occurs due to the apparatus at the value of H, FIG.
As shown in the above, since the correction was not performed until about 1.4 turns, there was an error of about 0.06 between the hand analysis value and the value obtained by the analyzer, but after correcting this, the error becomes Reduced to an acceptable level.

The results shown in FIG. 17 indicate that 520n which mainly changes due to turbidity measured in the apparatus.
It is a summary of transmittance measured at a measurement wavelength of m in relation to turns. Actually, the amount of PTFE particles in the plating solution is gradually increased by the replenishment as the turn progresses. Although this suggests that the transmittance gradually decreases, actually, the transmittance gradually increases and the turbidity tends to decrease. This is also due to the change due to the accumulation of aging as described above. This change in value appears as a large change in transmittance close to 4% up to about 2.6 turns. If it is assumed that the measurement is performed at one wavelength ignoring this variation, the error due to this variation may lead to an error of about 1.0 g / L. Not only measurement at two wavelengths, but also various existing turn correction functions in conventional electroless plating equipment that are commercially available, as long as the base solution is common to electroless plating solutions It can be understood from this result that it is absolutely necessary.

On the other hand, peculiar troubles may occur during running with various plating solutions. The problem is that the analysis value of Ni concentration suddenly shows an abnormally high value. At first, the cause could not be easily identified, but as a result of investigating and examining the cause, the following factors caused the problem. It became clear that there was. (1) The value fluctuates during the measurement of the absorbance because the bubbles contained in the sampled plating solution and transported into the absorption cell could not be sufficiently separated within a short time from the stop of sampling to the measurement of the absorbance. As a result, the analysis accuracy was deteriorated. Factors that tend to cause such inconvenience include the type of composite plating solution and aging of the plating solution. (2) Since the chemical supply position was close to the plating solution sampling position, sampling was performed without sufficient diffusion and uniformity of the supplied chemical, resulting in an abnormally high analytical value. (3) The stability of the switching mechanism of the interference filter is insufficient, and a slight vibration or impact on the device causes an error.

The following measures are effective against the causes of these problems. (1) In order to minimize the introduction of bubbles into the absorption cell, a vertical section having a cross-sectional area that is twice or more the cross-sectional area of the sampling pipe at an appropriate place in the apparatus piping until the plating solution reaches the absorption cell. A trap portion is provided so that bubbles formed by a plating solution stagnation portion that is long in the direction are easily separated. Specifically, an inlet through which the plating solution flows into the pH cell is provided above the pH cell, while an outlet is provided below.
Since the cross-sectional area of the pH cell is much larger than that of the sampling tube, the flow velocity is extremely reduced, so that large bubbles can escape to the upper part of the pH cell at this part, while bubbles are generated at the lower part of the pH cell. Is relatively reduced, so that the plating solution with less bubbles is easily supplied to the absorption cell located on the lower side thereof. (2) In order to perform absorption measurement while minimizing the influence of bubbles entering the absorption cell, the time from the stop of sampling of the plating solution to the start of absorption measurement is 15 seconds or more. Note that “after stopping sampling” means, for example, that after the first or second sample is caused to flow into the absorbance measurement unit 10 by the sampling pump 18 in the apparatus of FIG. Means that (3) Set the sampling position as far as possible from the position where the medicine is automatically supplied. (4) Modification to increase the mechanical strength and control the operation of the interference filter switching mechanism to suppress the fluctuation of the stop position and the effects of vibration and impact.

By these improvements, abnormal analysis values hardly occur. In particular, it is effective to extend the resting time from the stop of sampling to the start of absorbance measurement in the improvement (2).
If a stationary time of at least 2 seconds is secured, the fluctuation is suppressed to a level that does not cause any problem, but it is more preferably at least 30 seconds, most preferably at least 60 seconds. It can be said that this standing time is ideally set to be as long as possible. However, the need for the analysis frequency of the plating solution is as short as about 120 seconds. .

In addition to the above, a specific problem which is a problem when constructing an automatic analyzer / management apparatus for a composite plating solution is adhesion of dispersed particles to an absorption cell. Cell contamination is a factor that causes the transmittance or absorbance to fluctuate similarly to the dispersed particles in the plating solution. Although the analysis at a plurality of measurement wavelengths according to the present invention has an effect of improving this problem, the contamination of dispersed particles adheres to the absorption cell at a level that cannot be compared with a general electroless plating solution. In order to solve this problem, it is desirable to carry out cleaning at a relatively high frequency.However, cleaning the absorption cell incorporated in the device requires much time and effort such as removing the cell from the device, and Since the adhered dirt tends to be difficult to remove, ultrasonic cleaning, cleaning using an acidic (hydrochloric acid, nitric acid, etc.) or basic (caustic soda, ammonia, etc.) solution or detergent, and using an organic solvent such as ethanol etc. Is required. In the device,
Although some design improvements have been made, such as making the cell easier to remove, it is costly to incorporate an ultrasonic device or a mechanism to feed the above various cleaning solutions into the automatic analysis and management device for automatic cleaning of the inner surface of the absorption cell. Therefore, the structure of the apparatus becomes complicated, and the generation of waste liquids such as acids, alkalis, and organic solvents imposes a heavy burden on the user.

As described above, the analysis using a plurality of measurement wavelengths is indispensable because the turbidity of the plating solution to be analyzed may vary from one analysis to another.
However, the dirt on the light absorption cell often changes relatively slowly, and most of the problems at that time are only errors due to a change in the reference of 100% transmittance or zero absorbance in pure water as a reference, To some extent, it is corrected by measuring at two or more measurement wavelengths. For this purpose, it is necessary to perform measurement using a single absorption cell.For example, assuming a case where an absorbance measurement unit is designed such that an absorption cell is provided for each measurement wavelength, contamination may occur after the reference value measurement with pure water. Causes a large error in subsequent analysis values. Therefore, it is important to regularly measure a reference value of 100% transmittance or zero absorbance using pure water, and this problem is sufficiently mitigated in the above-described apparatus using one cell. is there.

For example, by calculating “the transmittance of pure water / 100 × the transmittance of the analysis sample” and the result of the analysis of the plating solution to be performed next, it is possible to reduce the error caused by the contamination of the absorption cell. . In addition, in order to prevent the contamination of the light absorption cell from affecting the analysis result so as not to be overlooked, the transmittance in the pure water is not less than a predetermined value (for example, 1%) from the previous measurement of the transmittance in the pure water. In the case of the above-mentioned fluctuation, an alarm is issued and the washing or replacement of the absorption cell can be prompted.

FIGS. 18 and 19 show an example of a plating apparatus incorporating the present apparatus. That is, FIG. 18 shows an example in which the main component is replenished mainly using a metering pump. Advantages of the metering pump type are that the equipment cost is relatively inexpensive and the replenishing amount can be controlled by the operation time. Therefore, it is possible to arbitrarily and automatically adjust the replenishing amount for each analysis result. on the other hand,
FIG. 19 shows an example in which the chemical solution of the main component is carried out by a column, which is advantageous in that the weighing stability of the replenishing amount is higher than that of the metering pump.

Here, in FIG. 18, reference numeral 20 denotes a plating tank to which an overflow tank 22 is additionally provided. 24 is a metering pump, 26 is a replenisher (nickel salt, reducing agent, complexing agent, etc.) tank, 28 is an alkali supply tank,
Numeral 30 denotes a composite material supply column, in which a replenisher, an alkali, and a composite material are supplied to an overflow tank, which flows into a plating solution in the plating tank. In FIG. 19, 32 is a metering pump, 34 is a supply column,
It is the same as the case of FIG. 18 except that the main replenisher is supplied using the column.

On the other hand, in FIGS. 18 and 19, reference numeral 36 denotes a cooling mechanism, in which the plating solution cooled to room temperature is supplied to the automatic analyzer / management apparatus 1 and the analysis is performed as described above. In the figure, 38 is a pure water tank, 4
0 is a pH 4 standard solution tank, and 42 is a pH 7 standard solution tank.

As described above, upon receiving the analysis value of the concentration measuring section B, the control section A calculates the analysis result. The control unit A controls the operation of the metering pump 24 and the composite material supply column 30 according to the analysis result. For example, when the analysis result indicates that the metal concentration in the plating solution is insufficient, the metering pump 24 of the replenisher tank is operated and stopped for a preset time. Alternatively, the metering pump 24 of the replenisher tank may be operated, and when the subsequent analysis result indicates that the shortage of the metal concentration has been resolved, the metering pump 24 may be stopped. The operation of the metering pump 24 of the alkali supply tank for pH adjustment can be similarly performed. The control of the composite material supply column is performed, for example, once when the number of actuations of the replenishing agent quantitative pump 24 reaches a predetermined number, or replenished into the plating solution from the operating time of the replenishing agent quantitative pump 24. By calculating the supplied metal amount and operating once when the replenished metal amount reaches the predetermined amount, the predetermined amount is supplied to the plating solution.

[0070]

According to the present invention, the metal ion concentration in the electroless composite plating solution can be easily and reliably analyzed automatically.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between measured wavelength and absorbance when the Ni concentration is changed from 0 to 5 g / L in an electroless nickel plating solution containing no PTFE.

FIG. 2 shows a PTFE composite material particle containing no metal component and an electroless plating solution (Ni concentration 0 g / L).
It is a graph which shows the relationship between a measurement wavelength and absorbance when changing FE density | concentration from 0 to 10 g / L.

FIG. 3 In an electroless composite nickel plating solution using PTFE as composite material particles, the Ni concentration is kept constant at 5 g / L.
It is a graph which shows the relationship between a measurement wavelength and absorbance at the time of changing a PTFE density | concentration from 0 to 10 g / L.

FIG. 4 is a graph showing the relationship between the Ni concentration and the absorbance at a wavelength of 400 nm when the PTFE concentration is changed from 0 to 10 g / L in an electroless composite nickel plating solution using PTFE as composite material particles. .

FIG. 5 is a graph showing the relationship between the PTFE concentration and the absorbance at a wavelength of 400 nm when the Ni concentration is changed from 0 to 5 g / L in an electroless composite nickel plating solution using PTFE as composite material particles. .

FIG. 6 is a graph showing the relationship between the Ni concentration at a wavelength of 520 nm and the absorbance when the PTFE concentration is changed from 0 to 10 g / L in an electroless composite nickel plating solution containing PTFE as composite material particles. .

FIG. 7 is a graph showing the relationship between the PTFE concentration and the absorbance at a wavelength of 520 nm when the Ni concentration is changed from 0 to 5 g / L in an electroless composite nickel plating solution using PTFE as composite material particles. .

FIG. 8 is a schematic front view of an automatic analysis and management device according to one embodiment of the present invention.

FIG. 9 is an explanatory diagram of a measurement unit of the device.

FIG. 10 shows a PTF using the same apparatus, with a constant Ni concentration.
5 is a graph showing the relationship between the absorbance at a wavelength of 660 nm and the wavelength of 520 nm measured for an electroless composite nickel plating solution having a different E concentration.

FIG. 11 shows K for the electroless composite nickel plating solution.
4 is a graph showing a relationship between a value and a Ni concentration.

FIG. 12 shows a PTF using the same apparatus with a constant Ni concentration.
Absorbance at a wavelength of 660 nm measured for another electroless composite nickel plating solution having a different E concentration and a wavelength of 520 n
It is a graph which shows the relationship with m.

FIG. 13 shows K for the electroless composite nickel plating solution.
4 is a graph showing a relationship between a value and a Ni concentration.

FIG. 14 is a graph showing the relationship between the number of turns (MTO) and the measured Ni concentration when electroless composite nickel plating is performed continuously.

FIG. 15 is a graph showing the relationship between the number of turns and the measured pH value when electroless composite nickel plating is performed continuously.

FIG. 16 is a graph for calculating a turn correction coefficient,
The relationship between the number of turns and the standard value of Ni concentration-error value is shown.

FIG. 17 is a graph showing the relationship between the number of turns and the turbidity value measured at 520 nm when electroless composite nickel plating is continuously performed.

FIG. 18 is a schematic view showing an example of an electroless composite plating apparatus incorporating the apparatus of the present invention.

FIG. 19 is a schematic view showing another example of an electroless composite plating apparatus incorporating the apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 10 Absorbance measurement unit 10a Absorbance cell 12 pH cell 14 Column 16 Temperature sensor 18 Sampling pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01N 21/27 G01N 21/27 Z 21/33 21/33 21/35 21/35 Z (72) Inventor Kazunori Yoshikawa 1-5-1, Hirakata Exit, Osaka Pref., Uemura Industry Co., Ltd. Central Research Laboratory (72) Inventor Shinji Tachibana 1-5-1, Exit 1, Hirakata City, Osaka Pref. Reference) 2G057 AA01 AB01 AB02 AB03 AB06 AC01 AD17 BA07 JA02 2G059 AA01 BB04 CC03 DD12 DD13 DD16 EE01 EE02 HH01 HH02 HH03 JJ03 MM01 MM12 MM14 NN07 PP02 PP04 PP06 4K022 BA06 BA14 BA32 BA34 DB28

Claims (7)

[Claims] An apparatus for automatically analyzing an electroless composite plating solution and automatically controlling the composition of the electroless plating solution to an appropriate solution composition and / or use condition, as a method of measuring the concentration of a metal component in the plating solution by an absorption spectrophotometry. Automatically introduces the plating solution into the analysis cell, then measures the transmittance or absorbance at at least two or more different wavelengths, calculates the target concentration from the measured value by arithmetic processing and displays the result An automatic analysis and management device for an electroless composite plating solution, comprising: 2. The automatic analysis / management apparatus according to claim 1, wherein at least one of the measurement wavelengths is split into a half width of 1 to 100 nm or less. 3. The combination of the measurement wavelengths is 250 to 350 nm or 450 to 5 as at least one measurement wavelength.
2. A combination in which a wavelength range of 50 nm is selected, and a wavelength range of 350 to 450 nm or 550 to 800 nm is selected as at least one measurement wavelength as another measurement wavelength not overlapping with this wavelength. Or the automatic analysis / management device according to 2. 4. A measurement time table is set so that a standing time of at least 15 seconds is secured before the measurement of transmittance or absorbance is started after the plating solution is automatically introduced into the analysis cell. 4. The automatic analysis / management device according to claim 1, wherein: 5. Periodically introducing pure water into the analysis cell to wash the inside of the analysis cell, and measuring transmittance or absorbance at a measurement wavelength set in a state where the pure water is filled in the cell. 100% transmittance or absorbance with respect to the measured value of transmittance or absorbance of the plating solution that is carried out within the time until the same measurement with pure water is performed. 5. The automatic analysis / management apparatus according to claim 1, wherein the automatic analysis / management apparatus is used as a reference value of zero. 6. A cross-sectional area of a sampling pipe which is smaller than a cross-sectional area of a sampling pipe in a sampling path for introducing a plating solution into an analysis cell.
It has a vertically long plating solution stagnation portion having a cross-sectional area of twice or more, and an inlet for the plating solution stagnation portion is provided at an upper portion,
6. A trap mechanism for providing an outlet at a lower portion to prevent fine bubbles entrapped in the plating solution from being brought into the analysis cell.
The automatic analysis and management device according to any one of claims 1 to 7. 7. The automatic analysis / management apparatus according to claim 1, wherein the electroless composite plating solution is an electroless composite nickel plating solution, and a nickel component in the plating solution is measured. .