JPS59219456A - Method and device for controlling chemical copper plating liquid - Google Patents

Abstract

PURPOSE:To control easily and surely the pH value or alkalinity of a chemical copper plating liquid contg. ethylene diamine as a complexing agent by detecting the pH value or alkalinity of the plating liquid from the absorbance and copper ion concn. of the plating soln. CONSTITUTION:A chemical copper plating liquid 2 which is an alkali soln. of >=8pH contg. ethylene diamine as a complexing agent in a plating cell 1 is pumped 4 to an absorbance measuring device 5 by which the absorbance of the liquid 2 is measured. On the other hand, the liquid 2 is pumped 10 to an absorbance measuring device 9 and after the pH of the liquid 2 is adjusted to <=8 by an acid adder 11, the absorbance thereof is measured. The copper ion concn. in the liquid 2 is then calculated from the measured absorbance value of the liquid having the above-mentioned low pH in a control device 8. The pH value or alkalinity of the liquid 2 is detected fron said concn. and the measured absorbance value of the liquid having the above-mentioned high pH. The detected value is compared with a set value and if the value is lower than the set value, an alarm signal A is emitted and a pH adjusting agent 16 is supplied from a pH adjusting vessel 15 to the cell 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for managing a chemical copper plating solution and an apparatus used therefor.

Conventionally, chemical copper plating solutions have been widely used in the manufacture of printed circuit boards, etc., but in the case of manufacturing printed circuit boards, the quality of the chemical copper plating solution does not directly affect the quality of the product. It is required to manage the liquid as strictly as possible.

Important control items for chemical copper plating solutions include copper ion concentration, reducing agent (formalin) viscosity, and solution level (or alkalinity).If these values deviate from the specified control concentration range, In particular, if the concentration drops below the lower control limit,
Problems arise such as a decrease in the copper precipitation rate and changes in the physical properties of the resulting chemical steel plating film.

For this reason, various methods and devices for automatically managing chemical copper plating solutions have been proposed, but none of the conventional methods and devices for automatically managing chemical copper plating solutions use glass electrodes to measure pH or alkalinity. I am using a pH meter. However, since chemical copper plating solutions are generally highly alkaline solutions, continuous measurement of pI or alkalinity using a pH meter using a glass electrode sound is not necessarily sufficient in terms of reliability or reproducibility; There are problems such as the meter deteriorates rapidly and maintenance and inspection are troublesome.

The present invention was made in view of the above circumstances, and aims to provide a method for managing a chemical copper plating solution that can easily and reliably manage the pH or alkalinity of the chemical copper plating solution, and all the apparatus used therein. .

In other words, 5 According to the studies of the present inventors, most chemical steel plating solutions use ethylenediamines as complexing agents;
In chemical steel plating solutions that use ethylenediamines as complexing agents, @Il! If If is constant, there is a correlation between the absorbance value of the chemical copper plating solution and the value or alkalinity at FJ (higher than 8), so the absorbance value of the chemical steel plating solution is It has been found that alkalinity or alkalinity can be accurately detected by measuring alkalinity at -. Then, by measuring the absorbance value of a chemical copper plating solution using ethylenediamine as a complexing agent at PI (higher than 8) and detecting the copper ion concentration of this chemical copper plating solution, these absorbance measurement results are Based on the copper ion concentration detection results, the pJ (value also ranges from 1 to <
can determine whether the alkalinity is below a preset m value or alkalinity, and by emitting a signal when the alkalinity is below a preset value or alkalinity. It was discovered that the alkalinity of a chemical copper plating solution can be reliably controlled, leading to the present invention.

At the same time, the copper ion concentration of the chemical steel plating solution is detected, and from the absorbance measurement result and the copper ion concentration detection result, the β value or alkalinity of the chemical copper plating solution is below the set pi (value or set alkalinity The present invention provides a method for managing a chemical steel plating solution, which is characterized in that a signal is emitted when a chemical steel plating solution is detected.

The present invention also provides an absorbance measuring device for measuring the absorbance of a chemical steel plating solution using ethylenediamine as a complexing agent at a temperature higher than -8, and a means for detecting the copper ion concentration of the chemical copper plating solution. , the absorbance measurement results and copper ion #
From the temperature detection result, it is determined whether the β value or alkalinity of the chemical copper plating solution is below the set value or the set del strength plate, and the β value or alkalinity of the chemical steel plating solution is set... The present invention also provides a chemical copper plating solution management device characterized by comprising means for emitting a signal when detecting that the alkalinity is below a set value or a set alkalinity.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

In the present invention, the chemical copper plating solution to be controlled includes copper ions, ethylenediamines 1 such as ethylenediaminetetraacetic acid, tetrahydroxypropylethelenediamine,
It is an alkaline type product containing N-hydroxyethylethylenediami/triacetic acid, salts thereof, and a reducing agent such as formalin. In this case, the chemical copper plating solution may contain, in addition to the above-mentioned components, other components such as complexing agents and stabilizers other than ethylenediamines.

The present invention is for continuously or intermittently detecting the alkalinity of a chemical copper plating solution of the type described above, and in this case, the detection involves detecting the absorbance of the chemical copper plating solution as high as PH8. - This is done by measuring the pH of the chemical copper plating solution depending on the measurement results.
A signal is generated when the value or alkalinity is less than a preset value or alkalinity. According to the findings of the present inventors, EDTA, 4N
In an alkaline solution in which metal ions such as copper ions are complexed with ethylenediamines in the presence of an excess of ethylenediamines such as a, if the metal ion concentration is constant, the absorbance value and... value or alkalinity will change. There is an almost linear relationship, so if you know the alkaline earth metal ion concentration and the absorbance value...or you can accurately know the alkalinity.In the present invention, first, the absorbance of the chemical copper plating solution is measured. In particular, there are devices designed to detect the value or alkalinity of chemical copper plating solutions.

Here, the detection of pH or alkalinity by absorbance measurement is carried out using an alkaline solution with a higher pH than that, preferably with a pH of
) It is necessary to rinse with an alkaline solution of 19 or higher, but
Since a chemical copper plating solution using ethylene diamide/s as a complexing agent is usually an alkaline solution with a pH of 9 or higher, the absorbance measurement for detecting pH or alkalinity can be carried out using the chemical copper plating solution as it is. However, if necessary, it is also possible to measure the absorbance of the plating solution by adding dioxylic acid to lower the -.

The embodiments shown in Figures 1 and 2 illustrate this. In Figure 1, 1 is a chemical steel plating tank containing a chemical steel plating solution 2, and 3 is a pipe in which a bo/p 4 is inserted. , one end of which is immersed in a chemical copper plating solution 2, and the other end connected to an absorbance measuring device 5. According to this embodiment, the pump 4 is operated continuously or at predetermined time intervals, and the chemical copper plating solution 2 in the tank 1 flows into the pipe 3, and then flows through the flow cell of the absorbance measuring device 5, and the chemical copper plating solution 2 flows through the flow cell of the absorbance measuring device 5. The absorbance of liquid 2 is 311j. In addition,
The damping liquid whose absorbance has been measured may be returned to the tank 1 through the pipe 6, or may be disposed of outside the system through the pipe 7.

can be set to a predetermined wavelength.

The absorbance measurement bundle obtained in this way is
When the absorbance measurement result is compared with a preset setting value and the alkalinity of the chemical copper plating solution detected from the absorbance measurement result is below the preset pH or alkalinity, the signal A is In this case, the absorbance measurement result is used to detect the alkalinity of the chemical copper plating solution, and the copper ion concentration of the chemical copper plating solution must be detected.

Therefore, although the present invention measures the absorbance of a chemical copper plating solution as described above, it is also necessary to detect the copper ion concentration of this chemical copper plating solution.

In this case, there is no particular restriction on the method of detecting the copper ion concentration of the chemical copper plating solution, and a direct detection method that determines the absolute value of the steel ion concentration may be used, or a single indirect detection method may be used. An example of this indirect detection method is to detect a state in which it is confirmed that the copper ion concentration of the plating solution is always at a certain value when measuring the absorbance.

for example.

In a certain chemical copper plating solution, if the copper ion concentration at the initial stage of use is constant, the amount of copper deposited when a certain area of the object to be plated is plated for a certain period of time is constant. Since the copper ion vorticity in the solution always decreases to approximately the same concentration, when plating a fixed area of an object, the copper ion concentration can be detected based on the plating time. Therefore, if the absorbance of the chemical steel plating solution is measured at every predetermined plating time, the copper ion concentration at the time of absorbance measurement is always almost the same, so simply compare the absorbance measurement result with the preset value. By doing so, it is possible to detect whether the alkalinity of the chemical steel plating solution is below a predetermined pH or alkalinity. Also in this case.

The amount of decrease in copper ion concentration after plating for a certain period of time is almost the same, so if you want to replenish a certain amount of copper ions accordingly and return to the original copper ion concentration, replenish copper ions l- Alternatively, the absorbance may be measured after the concentration of copper ions (in this case as well, the copper ion concentration is constant). Therefore, in this case, a timer can be used as the copper ion concentration detecting means. For example, the timer can be used to operate the bob/bob 4 shown in FIG. 1.2. Further, when the area of the object to be plated changes, the copper ion concentration may be detected by multiplying the area of the object by plating time.

However, from the viewpoint of plating solution management, it is more preferable to measure the copper ion concentration of the chemical copper plating solution by analysis. In this case, the method of measuring the copper ion concentration is not particularly limited, and various known methods may be employed, but it is preferable to measure the copper ion concentration by absorbance measurement.

The copper ion concentration is measured by this absorbance measurement.

A predetermined wavelength can be obtained by adding an acid such as sulfuric acid, hydrochloric acid, or acetic acid to a chemical copper plating solution. By measuring the absorbance in this way, there is a nearly linear relationship between the absorbance value and the copper ion concentration value at a given wavelength, so the copper ion concentration value can be detected from the obtained absorbance value. Ruru. Further, the device used to measure the absorbance of the chemical steel plating solution adjusted to -8 or less may be provided separately from the absorbance measuring device 5 described above, or may be used in common with the absorbance measuring device 5.

The embodiment shown in FIG. 1 is an example in which an absorbance measuring device 9 for a chemical steel plating solution of IIJ18 or less is separately provided. The other end of the pipe 12, in which the pipes 11 are successively interposed, is connected to the absorbance measuring device 9. When measuring the absorbance of the chemical copper plating solution 2 using one of the absorbance measurement devices 5, the valve 10 is operated at approximately the same time as this, and the plating solution 2 is introduced into the pipe 12. Add acid from the addition device 9 to make the plating solution 2 less than -18.

The absorbance of this chemical copper plating solution is measured by the other absorbance measuring device 9.
It is measured by

It is preferable that the plating solution after this absorbance measurement be disposed of outside the system through the pipe 13.

Further, the embodiment shown in FIG. 2 is an example in which the absorbance measuring device is shared, and an acid adding device 11 is attached to the pipe 3.

When measuring the absorption FK of the chemical copper plating solution itself to detect Pll or alkalinity, do not add acid.

When absorbance is measured for copper ion concentration detection immediately before or after this absorbance measurement, acid is added from the acid addition device 11 to bring the plating solution to 18 or less.

The absorbance measurement result of the chemical copper plating solution whose pH has been adjusted to below 8 is calculated in the control device 8, and the copper ion concentration value of the chemical copper plating solution can be determined based on this. The absorbance measurement results at pH 8 higher μm of the chemical copper plating solution at the copper ion concentration value are calculated and compared with the set value, and the copper ion concentration value and pl (from the absorbance measurement value of the chemical copper plating solution at 3 y υ Takada) are calculated and compared with the set value. If the calculated FJ (Mo-Shikke alkalinity) of the chemical copper plating solution is less than the preset setting - 4 value or the set alkalinity, the signal A is generated as described above. Therefore, In this case, the control device 8 is stored.

Computers with calculation and comparison functions are effectively used. In addition, if the plating solution's alkalinity is less than the set value, signal A is generated as described above, but in addition...the value is also 1 to 1, and if the alkalinity is higher than the preset value or alkalinity. It is also possible to issue a signal and give a warning in this case.

Here, the signal A can also be emitted as an alarm by a buzzer, etc., so that the operator can apply plating solution to the plating solution if necessary.
Although it is possible to take measures such as adding a conditioning agent to t', it is preferable to transmit the signal A to the conditioning agent replenishing device and p
i (It is best to automatically replenish the conditioning agent to the plating solution.

The embodiment shown in FIGS. 1 and 2 shows this, in which a signal A is transmitted to the electromagnetic pulp 14 to open the pulp 14 for a predetermined time, and the pH
A predetermined amount of the conditioning agent 16 in the tiMl conditioning tank 15 is added to the plating solution 2 in the tank 1 through a pipe 17. Although the pHN adjuster varies depending on the composition of the chemical copper plating solution, it usually contains alkali hydroxide as a main component, and in some cases, ammonia as a main component.

In addition, in terms of managing the chemical copper plating solution, the control device 8
When the copper ion concentration of the chemical copper plating solution calculated from the absorbance measurement result is less than or equal to a preset copper ion/concentration value, it is preferable to emit signal B. . Similar to signal A, this signal B can also be used to issue an alarm such as a buzzer, but it is effective to transmit signal B to a copper ion replenishment station to automatically replenish copper ions. That is, as shown in the embodiment of FIG. 1.2, the signal B is transmitted to the electromagnetic pulp 18, and a predetermined amount of the copper ion replenisher 20 in the copper ion/replenisher tank 19 is added to the plating solution 2 through the pipe 21. It is preferable to add it.

Note that the replenishing device for the FJ (N preparation agent and copper ion replenisher) is not limited to that shown in the drawings, and a metering pump or the like may be used as an example.

Furthermore, in the present invention, it is also possible to control the concentration of the reducing agent (formalli/) in the chemical copper plating solution.

This reducing agent (formalin) concentration can be controlled by employing an appropriate quantitative method, but in this case as well, the formalin concentration can be detected using the absorbance measurement method. That is, in this method, an acid such as sulfuric acid or hydrochloric acid is added to a chemical steel plating solution to adjust the pH to a predetermined value of -1, for example, PH7 to 10, and the absorbance at that time is measured. Next, add a certain amount of sulfite such as sulfite. As a result, an alkali is generated by the reaction between formalin and sulfite, and the - of the chemical copper plating solution increases, so an acid of known concentration is added until the absorbance of this plating solution matches the absorbance.

The forma v7m degree is calculated and quantified from the added amount of acid whose concentration is known. In this case, if the formalin # degree detected from the added amount of acid whose concentration is known is less than the preset formalin concentration.

It is possible to issue an alarm or give a command to the formalin replenishing device to automatically replenish formalin to the plating solution.

We also measured the absorbance values before and after adding sulfite.

From this, it is also possible to obtain the formalin bar by computer calculation.

Furthermore, if the consumption value of copper ions and the consumption amount of formalin are correlated and it is possible to convert the formalin concentration from the copper ion concentration, it is not possible to measure the copper ion concentration. When signal B is emitted, signal C is emitted at the same time.
It is also possible to emit signal C and supply ciformalin to the plating solution wA in accordance with the command of this signal C.

The embodiment shown in Figure 1.2 illustrates this.

At the same time as the signal B is issued, the signal C is issued, and the stain magnetic valve 22 is opened for a predetermined time by this signal C, and the formalin replenishment agent supply agent 24 in the formalin replenishment agent type 23 is transferred through the pipe 25 to the plating solution in the tank 1. 2, it was designed to supply supplies as needed.

Note that the formalin replenishment device is not limited to the illustrated embodiment.
Of course it's okay.

Generally, in chemical copper plating, as the plating progresses and the concentration of copper ion and reducing agent decreases, these components can be replenished accordingly, but it is necessary to stabilize the Ingredients such as the agent, and the complexing agent that is consumed by pumping, can be mixed with either replenisher 16.20 or 24 mentioned above, or supplied separately from replenisher 16.20 and 24. can be replenished accordingly.

In the embodiment shown in FIGS. 1 and 2 described above, the control device 8 receives the absorbance measurement result of 59 liquid main zero ↓ force and p)l! 1) The alkalinity of a chemical steel plating solution is calculated from the absorbance measurement of chemical copper plating with a concentration of d or less. However, the present invention is not limited to this, and may be configured as shown in FIG. 3, for example.

-1. In the embodiment shown in FIG. 3, the absorbance of the chemical copper plating solution with a trench PTT of 3 or less is measured by the absorbance measurement device 9, and the measurement result is compared with the set value by the control device 8a. When the binding reaches the set value (when the ion concentration of the chemical hammering solution falls below the preset copper ion concentration)
, signal B'f: is emitted. More specifically, as shown in FIG. 4, in the absorbance measuring device 9, the light 6'f emitted from the light source 26 passes through the flow cell 27. The original change absorbed by the liquid is detected by the light receiving element 28, and the minute current from the light receiving element 28 is transmitted to the input terminal 29 of the control device 8a, where it is amplified by the Jt and q amplifier 30. It is converted into voltage and displayed on the voltmeter 31 as pressure corresponding to the absorbance. On the other hand, in the heavy pressure setting circuit 32, the output voltage of the amplifier 30 is compared with a preset voltage value, and when the set voltage is reached,
A signal B is emitted from the output terminal 33. The control device 8a is further provided with a counter 34 that counts the number of times the signal B is issued, and detects this every time the number of times the signal B is issued reaches a preset number. A number setting circuit 35 is provided, and when the number of times the signal B is issued reaches a certain number, a signal S is issued from the output terminal 36, and this causes the aging degree of 2 due to chemical copper plating to be reduced. It is now being detected.

The signal B is then transmitted to the copper ion replenisher device, and the copper ion replenisher 20 is replenished into the plating solution 2, so that the copper ion concentration in the plating solution 2 returns to the original concentration.

Therefore, at the time when the signal B is issued, the copper ion concentration of the setting needle 2 is almost the same as the set copper ion/r, or after the signal B is given and the copper ions of the quality needle are replenished. Since the copper ion concentration of the plating solution 2 returns to the original concentration, it is clearly detected that the copper ion concentration is at a substantially constant value in any of these cases. Therefore, when signal B is issued, the transmission of signal B to the copper ion replenishment device is delayed, and the control device 8a issues signals 1 to 4 before replenishing copper ions. Do you want it to work?

Alternatively, after supplying copper iodine by supplying signal B to the ion/replenishment device, signal B is issued and pump 4 is activated (or pump 4 is placed in a trench or absorbance measurement device that is kept in constant operation). 5 can also be turned on/off by signalling.)
Then, the absorbance of the plating solution 2 itself (or the blocking solution to which an acid has been added so that the pH does not fall below 8) is measured using an absorbance measuring device 5. In some cases, when continuously analyzing the copper ion concentration of the chemical copper plating solution 2, a comparison circuit separate from the control device 8a is provided,
When the copper ion concentration of the plating solution 2 matches a preset copper ion concentration value, a signal can be emitted.

Chemical copper plating solution 2 with a pH higher than 8 thus measured
The absorbance value is compared with a preset absorbance value (set value) by the control device 8b, and when the measured absorbance value reaches the set value, a signal A is generated.

This signal A is transmitted to the electromagnetic pulp 14 of the vibrator 17 connected to the tank 15 containing the PI (adjustment agent 16).

When this pulp 14 is opened for a certain period of time, a predetermined adjustment agent 16
is supplied to chemical copper plating solution 2.

In addition to measuring at a higher temperature, the copper ion concentration of the chemical copper plating solution is detected, and the value or alkalinity of the chemical copper plating solution is set from the absorbance measurement result and the copper ion concentration detection result. The present invention is characterized by emitting a signal when it detects that the alkalinity is below, and the present invention is not limited to the embodiments described above, but various modifications can be made within the scope of the gist of the present invention. According to the present invention, as is clear from the above, the pH, alkalinity, and potassium level of the chemical copper plating solution can be controlled satisfactorily. In particular, the alkalinity of the chemical copper plating solution is not measured with a pH meter using a glass electrode, but is controlled by measuring the absorbance using an absorbance measuring device, so the pH must be controlled accurately. It is easy to maintain and inspect.

The burden of maintenance and inspection is greatly reduced.

Below, υP is determined by measuring the absorbance of chemical steel plating solution.
A cooperative example of managing and obtaining H is shown in the following experimental example.

Example The following composition CuSO4.5f120 0.04 mo/l//
Create a solution of 13EDTA・4NaO,08l, and adjust its pH with NaOH and H2S04
was adjusted to various values.

Next, the absorbance and - of these solutions were measured.

The results shown in Figure 5.6 were obtained.

The absorbance was measured using a Hitachi double beam spectrophotometer old model 124 at a wavelength of 730 nm and an Igm cell. Also,
PH is Hitachi-Horiba F-711 type PH Me VcP)'19
In the above, it was recognized that the absorbance value and the ... value had a substantially linear relationship. It was also found that the absorbance value was almost constant at ypHB pH, and therefore, the copper ion concentration could be effectively determined by the absorbance method at pH 8 or lower.

Example below composition Gush<@5H200.04mol/1lED
TA・4Na O, 08# formalin
The absorbance at a wavelength of 730 nm of a chemical copper plating solution of 0.08# glycine 0.06# PH12,5CP14 meter measurement) was measured (using the above-mentioned absorbance measuring device, 1 g cell). The result was an absorbance of 0.225, and when - was calculated from the calibration curve shown in Figure 6, it was 12.5. Therefore, it was confirmed that the PI value obtained from the absorbance measurement and the OPH value obtained from the -meter agreed with each other.

[Brief explanation of drawings]

1 to 3 are respectively schematic explanatory diagrams showing one embodiment of the apparatus of the present invention, FIG. 4 is a block diagram of the absorbance measuring device for copper ion concentration and the control device of the apparatus of FIG. 3, and FIG. The figure and FIG. 6 are graphs showing the relationship between the absorbance value and the value of the copper-EDTA-4Na complex compound-containing solution, respectively. 1...Chemical steel plating bath, 2...Chemical copper plating solution, 5
゜9... Absorbance measurement device, 8, 8a, 8b... Control device. 16...pH replenisher. Applicant Uemura Kogyo Co., Ltd. Agent Takashi Kojima ■ Figure 3D

Claims (1)

[Claims] 1. The absorbance of a chemical copper plating solution using ethylenediamine as a complexing agent is measured at pi-18 or higher, and the copper ion concentration of the chemical copper plating solution is detected; A chemical copper plating solution that emits a signal when it is detected from the absorbance measurement result and the copper ion concentration detection result that both values or alkalinity of the chemical steel plating solution are below a set value or a set alkalinity. Management method. 2. The method according to claim 1, wherein the copper ion concentration is detected by measuring the copper ion concentration of a chemical copper plating solution. 3. Add acid to the chemical copper plating solution to make it less than 18, and measure the absorbance of the chemical copper plating solution that has become p[-18 or less, υ, to measure the copper ion concentration of the chemical copper plating solution. The method according to claim 2, wherein the method is as follows. 4. An absorbance measuring device for measuring the absorbance of a chemical copper plating solution containing ethylenediamine as a complexing agent at a pI higher than -8; a means for detecting the copper ion concentration of the chemical copper plating solution; From the measurement results and the copper ion concentration detection results, it is determined whether both values or the alkalinity of the chemical copper plating solution are below the set value or the set alkalinity, and whether the both values or the alkalinity of the chemical copper plating solution are below the set value or the set alkalinity. A chemical copper plating solution management device characterized by comprising means for emitting a signal when detecting that the pH value or alkalinity is below a set value. 5. The means for detecting copper ion concentration is a chemical copper plating solution. 6. The device for measuring copper ion concentration is the device according to claim 4.6. 7. An absorbance measuring device for measuring the absorbance of a chemical copper plating solution that has a pH of 8 or less. 7. The apparatus according to claim 6, which is used in common with an absorbance measuring apparatus for measuring absorbed luminous intensity of a chemical copper plating solution at a pH higher than 8.