JPH0697223B2 - Method and apparatus for detecting deposition rate of electroless plating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is an electroless plating bath (hereinafter simply referred to as a plating bath).
TECHNICAL FIELD The present invention relates to a deposition rate detection method and apparatus for electroless plating, which performs precise control of a deposited film thickness of a plated object dipped in a bath and detects an abnormal deposition reaction in a plating bath.

(Problems to be Solved by Conventional Techniques and Inventions) Conventionally, so-called galvanostat method and coulostat method have been used to detect the deposition rate of electroless plating.

Then, in the galvanostat method, the measurement sample piece plated in the plating bath is taken out from the plating bath and placed in a separately prepared electrolytic bath to electrolytically elute the plated coating, and the time required for this electrolytic elution To measure the plating film thickness.

In this case, since this method uses two baths, a plating bath and an electrolytic bath, it is necessary to alternately insert and remove the measuring electrodes between the two baths, which not only complicates the mechanical structure of the device. Instead, it was necessary to set the plating conditions and electrolysis conditions individually and optimally.

Therefore, it is necessary to check these conditions for each type of plating bath before plating the object to be plated,
Various preparations were required before the start of use, which was troublesome.

On the other hand, in the so-called coulostat method in which a predetermined charge is momentarily applied to the object to be plated or the sample piece, and the time change of the polarization accompanying this is measured and analyzed to calculate the deposition rate of the plating bath, the measured data is analyzed. Therefore, there is a drawback that the arithmetic unit becomes large and expensive.

The present invention has been made in view of the above circumstances, it is not necessary to prepare an electrolytic bath or the like separately from the plating bath, the deposition rate can be directly measured in the plating bath, and various preparations such as determination of a coefficient before the start of plating are performed. It is an object of the present invention to provide a deposition rate detection method for electroless plating and a device therefor, which does not require the above, is less troublesome, is inexpensive, and is relatively simple and can detect the deposition rate accurately.

(Means for Solving Problems) In order to achieve the above object, the present invention provides a method for detecting the deposition rate of electroless plating, in which an anode (E ₁ ) and a working electrode (E ₂ ) are placed in an electroless plating bath. And the cathode (E ₃ ) are immersed respectively, and the working electrode (E ₂ ) is used as a cathode and a current is passed between the anode (E ₁ ) and the anode (E ₁ ) at a constant current value for a certain time, and the working electrode (E ₂ ) is coated with a plating film. Immediately after performing the first initiation operation for electrolytic deposition, the working electrode (E ₂ ) is used as an anode in the plating bath at a constant current value between the working electrode (E ₂ ) and the cathode (E ₃ ). The first plating film peeling operation for electrolytically eluting the plating film on (E ₂ ) is performed, and the electrolytic voltage between the working electrode (E ₂ ) and the cathode (E ₃ ) at the time of this electrolytic elution is monitored, 1 The voltage rises sharply from the time (T ₀ ) when electrolytic elution is started by the plating film peeling operation. Identical with the initiation operation the same current value between the time (T ₁₎ until the time (T ₁ -T ₀₎ was measured, then the working electrode (E ₂₎ the anode and as a cathode (E ₁₎ was This working electrode (E ₂ ) is energized for a time
A second initiation operation of electrolytically depositing a plating film on the surface is performed, and immediately thereafter, the energization between the anode (E ₁ ) and the working electrode (E ₂ ) is stopped, and the working electrode ( E ₂ ) is left in the plating bath,
After electrolessly depositing a plating film on the electrolytically deposited plating film, immediately between the working electrode (E ₂ ) as an anode and the cathode (E ₃ ) in the plating bath, A second plating film peeling operation is carried out in which the plating film on this working electrode (E ₂ ) is electroeluted by applying the same current value as the plating film peeling operation, and the working electrode (E ₂ ) and cathode ( monitoring the electrolysis voltage between E _3), when the voltage from the time (T ₀₎ of electrolytic dissolution is initiated by the second plating film peeling operation has risen rapidly (T ₂₎ until the time (T ₂ -T ₀ )
Is measured and the deposition rate of the electroless plating bath is calculated from the difference (T ₂ −T ₁ ) between the two times.

In addition, as an apparatus for carrying out such a method, a sensor probe portion having an anode (E ₁ ), a working electrode (E ₂ ) and a cathode (E ₃ ) which are respectively immersed in an electroless plating bath, 4 includes a switch (SW _{1 to 4)} and a voltmeter, wherein the anode (E ₁₎ and the first switch (SW _1), the working electrode and (E ₂₎ a second switch (SW ₂₎ and the third switch (SW ₃ ), the cathode (E ₃ ) and the fourth switch (SW ₄ ) are connected to each other,
To a sensor interface unit which performs on-off of the fourth switch (SW _{1 to 4),} with an anode terminal connected to the first and second switch (SW _1, SW _2), the cathode terminal third and A power supply unit connected to the sensor interface unit so as to be connected to a fourth switch (SW ₃ , SW ₄ ), a measurement unit connected to the voltmeter and reading a voltage value, and the first to fourth switches ( is connected to the SW ₁ ~SW _4),
And a CPU section having a control section for controlling ON / OFF of these first to fourth switches (SW _{1 to} SW ₄ ),
This CPU section turns on the first and third switches (SW ₁ , SW ₃ ) respectively and turns off the second and fourth switches (SW ₂ , SW ₄ ) respectively, and the anode (E ₁ ) and the working electrode ( a fixed time energized, the first initiation command function for electrolytic deposition of plating film on the working electrode (E ₂₎ at a constant current between the E _2),
Immediately after completion of this electrolytic deposition, the first and third switches (SW
₁ , SW ₃ ) is turned off, and the 2nd and 4th switches (SW ₂ , SW ₄ )
Is turned on to energize the working electrode (E ₂ ) and the cathode (E ₃ ) at a constant current value to electrolytically elute the plating film on this working electrode (E ₂ ). Monitoring the change in the electrolytic voltage between the working electrode (E ₂ ) and the cathode (E ₃ ) at the time of electrolytic elution measured by the voltmeter of the sensor interface unit, and electrolytic elution by the first plating film peeling command. There was measured when starting the (T ₀₎ when the voltage rises rapidly from (T ₁₎ until the time (T ₁ -T _0), the function of storing the first and third switches (SW _1, SW ₃ ) is turned on and the second and fourth switches (SW ₂ , SW ₄ ) are turned off, respectively, and the same as the first initiation command is given between the anode (E ₁ ) and the working electrode (E ₂ ). A second initiation in which a plating film is electrolytically deposited on the working electrode (E ₂ ) by applying an electric current for the same time. A down command function further given to the electrolytic deposition of completion immediately after at least the second and third switches (SW _2, SW ₃₎ electrolytic deposition has been plated onto film on the working electrode by turning off the (E ₂₎ The electroless plating command function of depositing the electroless plating film for a period of time, and immediately after the completion of the electroless plating, the second and fourth switches are turned on to switch between the working electrode (E ₂ ) and the cathode (E ₃ ). (1) A second plating layer peeling command function of energizing at the same current value as the plating layer peeling command to electrolytically elute the plating layer on this working electrode (E ₂ ), and the electrolysis measured by the voltmeter of the sensor interface section The change in the electrolysis voltage between the working electrode (E ₂ ) and the cathode (E ₃ ) during elution was monitored, and the voltage suddenly increased from the time when the electrolysis elution was started by the second plating film peeling command (T ₀ ). When I got up to (T ₂ )
With measuring the time (T ₂ -T ₀₎ up to this time (T ₂
-T ₀ ) and the time (T ₁ -T ₀ ) difference (T ₂ -T ₁ ) to calculate the deposition rate of the electroless plating bath.

In this case, in carrying out the above-mentioned method, before the initiation operation, the anode (E ₁ ) and the working electrode (E ₂ ) are used as the respective anodes and electricity is conducted between the cathode (E ₃ ). ₁ ) and the working electrode (E ₂ ) are preferably cleaned anodically, and the same cleaning can be performed after the plating film peeling operation and before the second initiation operation. It is preferable to add such a cleaning command function.

In the method and apparatus described above, the initiation time is preferably 1 to 120 seconds, particularly 3 to 60 seconds. The initiation current varies depending on the type of plating bath, but the cathode current density is 4 to 20 A. / dm ² is preferable. Also, the anode current density for electrolytic elution is 4 to 20.
A / dm ² is preferable, and when cleaning is adopted, the cleaning time is 1 to 120 seconds, especially 3 to 60 seconds.
Second, the anode current density can be 4 to 20 A / dm ² .

The type of electroless plating bath to which the method of the present invention is applied is not limited, and nickel, cobalt, copper,
Examples include electroless plating baths such as alloys containing these metals.

(Operation) In the method and apparatus according to the present invention, the first and second initiations are performed at the same electrolytic energization current value and the same energization time, and after the second initiation, electroless plating is performed for a predetermined time to perform the first initiation. Since the deposited film is peeled off at the same electrolytic current value after each other after the second initiation and the second electroless plating, the times T ₁ -T ₀ and T ₂ -T ₀ required for each peeling are obtained. ,
The difference T ₂ −T ₁ between the _two times is the peeling time corresponding to the amount of deposition due to only electroless plating because the peeling time corresponding to the amount of deposition of the plating film due to initiation is deleted. Therefore, the deposition rate by electroless plating can be accurately calculated from the difference between both times. That is, since the amount of deposition and the time required for peeling the deposited film have a constant relationship in the same plating bath and the same current value, the peeling time (T ₂ −
The amount of deposition can be calculated from (T ₁ ), and this amount of deposition is the amount of deposition when electroless plating is performed for a predetermined time. In electroless plating, the amount of deposition is proportional to the plating time at a constant temperature. From the above, the deposition amount per unit time, that is, the deposition rate is calculated from the deposition amount and the electroless plating time.

An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment) FIG. 1 shows an embodiment of a deposition rate detection apparatus for electroless plating according to the present invention, which comprises a sensor probe section 1, a sensor interface section (hereinafter simply referred to as a sensor I / F section). 2, CPU section 3, display section 4, operation key input section 5, communication / control interface section (hereinafter simply referred to as communication / control I / F section) 6, data printing section 7, power supply section 8
It is configured so that the measurement conditions can be set and the measurement data can be saved automatically.

That is, the sensor probe unit 1 is composed of an anode E ₁ , a working electrode E ₂ , and a cathode E ₃ which are immersed in the plating bath 9, and each electrode E ₁ , E ₂ , E ₃
The surface area of each of the electrodes is obtained in advance, and each of the electrodes E ₁ , E ₂ , and E ₃ is connected to the sensor I / F section 2.

Then, the electrodes E ₁ and E ₂ are made of an insoluble material such as platinum,
The material of the electrode E ₃ is not particularly limited, but any material that does not react with the plating bath may be used.

The sensor I / F unit 2 has a switch SW as shown in FIG.
_{1 to 4} and a voltmeter 10 are provided, the switches SW ₁ to ₄ are opened and closed according to a command from the CPU unit 3, and electrode information such as electrode voltage from the sensor probe unit 1 is measured and transmitted to the CPU unit 3. It is connected to the CPU unit 3 and the power supply unit 8.

Here, the anode E ₁ of the sensor probe unit ₁ is the sensor I / F.
It is connected to the first switch SW ₁ of the part 2, the working electrode E ₂ is connected to the second switch SW ₂ and the third switch SW _3, and the cathode E ₃ is connected to the fourth switch SW ₄ and And the second
The switches SW ₁ and SW ₂ are connected to the cathode terminal of the power supply unit 8, and the third and fourth switches SW ₃ and SW ₄ are connected to the cathode terminal of the power supply unit 8.

The CPU unit 3 is an A / D that converts the voltage data of the voltmeter 10.
Comparator 12, and the first to fourth on the switch SW _{1 to 4,} a switch control output unit 11 to control the off, A / D comparator 12, the switches controlling the output unit 11 the voltmeter 10, the switch SW _It is connected to _1-4 .

Further, the CPU unit 3 is connected to the display unit 4, the operation key input unit 5, the communication / control I / F unit 6, the data printing unit 7 and the power supply unit 8, and the CPU main body 14 (ROM, RAM) is used to display the measurement conditions. It stores and calculates input information, and transmits this information and commands to the sensor I / F unit 2, the display unit 4, the communication / control I / F unit 6, and the data printing unit 7.

The display unit 4 displays the measured electrode voltage, measurement conditions, etc. based on a command from the CPU unit 3.

The operation key input section 5 is for inputting the start and end of the apparatus and each measurement condition via the CPU section 3.

The communication / control I / F unit 6 transmits commands and measurement data from the CPU unit 3 to an external device such as an automatic liquid management device, and drives the external device according to setting conditions and measurement conditions of the CPU unit 3. To do.

The data printing unit 7 prints and records measured values, measurement conditions and the like.

Here, the CPU unit 3 is provided with the first and second units as shown in FIG.
And the fourth switches SW ₁ , SW ₂ , SW ₄ are turned on, the third switch SW ₃ is turned off, and the electrolysis current value is kept constant between the anode E ₁ and the working electrode E ₂ and the cathode E _3. Energize for a predetermined time,
The anode E ₁ and the working electrode E ₂ are dissolved anodically with respect to the cathode E ₃ ,
The first cleaning cleaning command function for the surfaces of the anode E ₁ and the working electrode E ₂ , and the first and third switches SW ₁ ,
SW ₃ is turned on, the second and fourth switches SW ₂ , SW ₄ are turned off, and a current is passed between the anode E ₁ and the working electrode E ₂ at a constant current value for a certain time, and the working electrode E ₂ is plated. First to electrolytically deposit
Immediately after the completion of this electrolytic deposition, the first and third switches SW ₁ and SW ₃ are turned off, the second and fourth switches SW ₂ and SW ₄ are turned on, and the working electrode E ₂ and the cathode E are turned on. ₃
The first coating film peeling command function of electrolyzing the plating film on the working electrode E ₂ by conducting a constant current value between the working electrode E ₂ and the working electrode E at the time of electrolytic elution measured by the voltmeter of the sensor interface section. _The function of measuring and storing the time T ₁ (T ₁ −T ₀ ) from the start of electrolytic elution to the time when the voltage rises sharply by monitoring the change in the electrolytic voltage between ₂ and the cathode E ₃ .
Next, similarly to the first cleaning command function, the first, second and fourth switches SW ₁ , SW ₂ , SW ₄ are turned on and the third switch SW ₃
Is turned off to energize the anode E ₁ and the working electrode E ₂ and the cathode E ₃ for a predetermined time while keeping the electrolytic energization current value constant, and the anode E ₁
And a second cleaning command function of electrolytically electrolyzing the working electrode E ₂ with respect to the cathode E ₃ to clean the surfaces of the anode E ₁ and the working electrode E ₂ , and the first and third switches SW ₁ , SW ₃ Is turned on, the second and fourth switches SW ₂ and SW ₄ are turned off, and a current is applied between the anode E ₁ and the working electrode E ₂ at the same current value as the first initiation command for the same time,
A second initiation command function for electrolytic deposition of plating film on the working electrode E _2, the working electrode E ₂ in this electrolytic deposition of completion immediately after the first to fourth switches SW _{1 to 4} off
The electroless plating command function of further depositing the electroless plating film on the electrolytically deposited plating film for a predetermined time, and immediately after the completion of the electroless plating, the second and fourth switches are turned on to make the working electrode E ₂ and the cathode. With the second film peeling command function of energizing between E ₃ with the same current value as the first film peeling command to electrolytically elute the plating film on the working electrode E ₂ , and the voltmeter of the sensor interface section. The time T ₂ (T ₂ −T ₀ from the start of electrolytic elution to the time when the voltage suddenly rises is monitored by monitoring the change in the electrolytic voltage between the working electrode E ₂ and the cathode E ₃ during electrolytic elution. ) Is measured and the deposition rate of the electroless plating bath is calculated from the difference from the time T ₁ .

Next, regarding the deposition rate detection method for electroless plating according to the present invention, when this device is used in an electroless nickel plating bath consisting of Nimden 78S bath (manufactured by Uemura Kogyo Co., Ltd.), a flow chart of the program of this device ( 5 and 6) will be described.

First, as shown in FIG. ₁ , _three anodes E ₁ connected to the switch SW ₁ , a working electrode E ₂ connected to the switches SW ₂ and SW _3, and a cathode E ₃ connected to the switch SW ₄ are provided. The electrodes are placed in a plating bath 9 in which the object to be plated is immersed.

Next, as shown in FIG. 2, when the operation key input unit 5 is input to start the device, the switches SW ₁ , SW ₂ , SW ₄ are turned on (step), and the electrolysis current value is kept constant. electrode E in a state where maintaining the _1, E ₂ is an anode current density 8A to the electrode E ₃ /
Electrolytically electrolyzed at dm ² for about 5 seconds, electrode E
_After the surfaces of ₁ and E ₂ are cleaned (steps), the switches SW ₂ and SW ₄ are turned off (step a) while the switch SW ₁ remains closed, and the cleaning of the electrodes E ₁ and E ₂ is completed. . (Step ... First cleaning operation) Immediately after that, the switch SW ₃ is turned on (Step b), and the electrode E ₂ is cathodically electrolyzed with respect to the electrode E ₁ to about 5
Initiation is performed at a cathode current density of 8 A / dm ² for ² seconds (step c), and the plating film is electrodeposited on the electrode E ₂ . (Step ... First Initiation Operation) Next, the switches SW ₁ and SW ₃ are turned off (step d), the initiation is completed, and the switch SW is turned on.
₂ , SW ₄ is turned on (step e), and the electrolysis current value is kept constant, and is electrolyzed anodically with respect to the electrode E ₃ .
The plating film on the electrode E ₂ deposited during the initiation is electrolytically eluted. (Step ... First plating film peeling operation) At this time, the change in the electrolytic voltage v between the electrodes E ₂ and E _{3 in} the plating bath is continuously measured by the voltmeter 10 of the sensor I / F unit 2 and the measured value is obtained. Is monitored by the CPU unit 3, and T ₁ is measured and detected when the voltage rises rapidly (steps e to h).

After that, the switch SW ₁ is closed while the switch SW ₃ is off and the switches SW ₂ and SW ₄ are on (step). As a result, the electrodes E ₁ and E ₂ are connected to the electrode E _{3 under} the same conditions as in the first cleaning operation while keeping the electrolytic current value constant.
After the surface of the electrodes E ₁ and E ₂ is cleaned (stepped) for about 5 seconds, the switch SW
_{While 1} is still closed, the switches SW ₂ and SW ₄ are turned off (step a), and the cleaning of the electrodes E ₁ and E ₂ is completed. (Step ... Second cleaning operation) Immediately after that, the switch SW ₁ is turned on, and the electrode E ₂ is set to the first
The electrode E _{1 is} cathodically electrolyzed under the same conditions as the initiation operation, the initiation is performed for about 5 seconds, and the plating film is electrodeposited on the electrode E ₂ . (Step ... Second initiation operation) After that, the switches SW ₁ and SW ₃ are turned off, and the electroless plating deposition reaction occurs on the electrode E ₂ from this point, and the electroless nickel plating on the electrode E ₂ is performed for 1 minute (step). Is applied (step).

Then, immediately after the switches SW ₁ and SW ₃ are kept open, the switches SW ₂ and SW ₄ are closed, and the electroless energization current value is kept constant under the same conditions as the first plating film peeling operation. The plating film on E ₂ is dissolved by electrolysis.
(Step ... Second plating film peeling operation) At this time, the change of the electrolytic voltage v between the electrodes E ₂ and E ₃ in the plating bath is continuously measured by the voltmeter 10 of the sensor I / F unit 2 and the measured value is obtained. Is monitored by the CPU unit 3, and when the voltage suddenly rises (end point T ₂ ) is measured and detected, the switch SW ₂ ,
SW ₄ turns off and all switches turn off,
The detection measurement operation is ended (steps e to h).

Then, based on these results, the CPU section 3 calculates and calculates the time (T ₂ −T ₁ ) for electrolytically eluting the plating film deposited on the electrode E ₂ by only the electroless plating to obtain the plating rate and obtain various data. The data is printed by the data printing unit 7 and the record is saved.

That is, the electrolytic conduction current by a command and sensor I / F section 2 from the CPU 3 of the present device performs the initiation while maintaining constant the electrode E ₂ precipitated during initiation as shown in Fig. 3 The time required for electrolytic elution of the deposit (T ₁ −T ₀ ) and the time required for electrolytic elution of the film deposited on the electrode E ₂ by initiation and subsequent electroless plating (T ₂ −T ₀ ) were measured. Time required for electrolytic elution of the film deposited on the electrode E ₂ by only electroless plating (T ₁₂
-T ₁ ) is calculated to obtain the amount of electricity, and the fact that this amount of electricity appears in a form substantially proportional to the weight of the plating film is used to obtain the plating rate (step).

What is shown as A in FIG. 4 is an electroless nickel plating bath which is a Nimden 78S bath (manufactured by Uemura Kogyo Co., Ltd.), and the bath temperature is 75 ° C., 80 ° C., 85
The measurement results at temperatures of 90 ° C., 90 ° C., and 95 ° C. are expressed with the plating rate obtained by measuring in a 90 ° C. plating bath as 100.

Further, for comparison, as a control example, as in the above-mentioned example,
Nimden 78S bath heated to each temperature (Kamimura Industry Co., Ltd.)
The sample piece is immersed in each electroless nickel plating bath for 5 minutes to plate, the thickness of the plating film is measured with a fluorescent X-ray film thickness meter, and the plating speed in the plating bath at 90 ° C is set to 100. The calculated result is shown as B.

As is clear from this result, the plating rate monitored using the method and apparatus of the present invention almost coincides with the result of the control example, and corresponds well with the actual plating rate.

In addition, in the above embodiment, the set current density was described as an example set to be 8 A / dm ² with respect to the area of the electrode E ₂ , but the set current density can be variously selected and is not particularly limited. no, but it is preferable that the current density during initiation is 4A / dm ² or more, the area of the electrodes E _2, when setting the current density is less than 4A / dm ^2, the effect of initiation on electrode E ₂ There are cases where it cannot be obtained.

In this case, it is recommended that the current density with respect to the electrode E ₂ be constant within the first cycle because of the ease of setting,
Different current densities can be adopted for each operating stage. However, the first and second initiation operations and the first and second plating film peeling operations should have the same current density.

Further, in the above embodiment, the initiation time is about 5
Although it is set to be a second, the initiation time varies depending on the type of bath and is not limited. But 1-120
Seconds, particularly 3 to 60 seconds are preferred. If the initiation time is too short, the electroless plating reaction will not start on the electrode E ₂ , and if the initiation time is longer, on the other hand, the frequency of detection on the object to be plated will be less frequent within the specified plating time. Because it will occur. However,
The times of the first and second initiation operations should be the same as each other.

Further, in the above-mentioned embodiment, the example in which the electroless nickel plating is applied to the electrode E ₂ for 1 minute has been described. However, the plating time on the electrode E ₂ differs depending on the type of the bath, and further the second plating film peeling operation time is changed. It is selected according to how much you plan. Generally, it can be freely set within a range from several tens of seconds to several minutes.

Furthermore, the current density for the electrode E ₂ in the first and second plating film peeling operations is also appropriately selected according to the type of plating bath, but if the current density is too small, electrolytic elution takes time, or electrolytic elution occurs. 4A / dm ²
Above all, it is particularly preferable to be ⁴ to 20 A / dm ² .

Here, the areas of the electrodes E ₁ , E ₂ , and E ₃ are 0.
It is preferably about 005 to 25 dm ² .

In addition, in the above-mentioned embodiment, an example in which an electroless nickel plating bath of Nimden 78S bath (manufactured by Uemura Kogyo Co., Ltd.) is used is explained, but the type and composition of the electroless plating bath are not particularly limited. . However, the method and apparatus of the present invention
It is preferably applied to an acidic electroless plating bath, particularly an acidic electroless nickel plating bath.

In addition, in the above-mentioned embodiment, an example was given in which the electrolytic elution time T ₁ of the plating film by only the initiation was determined for each cycle, but the electrolytic elution time of the plating film by the initiation only in the subsequent cycles is also the plating film by the initial initiation only. When the electrolysis elution time of is also almost constant, only the electrolysis elution time in the first cycle may be obtained, and the measurement of the electrolysis elution time in the subsequent cycles may be omitted.

Furthermore, in the above-described embodiment, after the start of the apparatus, the electrode E ₂ was described as cleaning, initiation, electrolytic elution, cleaning, initiation, electroless plating, electrolytic elution as one cycle, but in the case of continuous measurement, etc. After starting the device, cleaning, initiation, electrolytic elution, initiation, electroless plating, electrolytic elution, initiation, electroless plating, electrolytic elution,
.., the intermediate second cleaning operation may be omitted, or all cleaning operations may be omitted in some cases. In other words, cleaning, may nucleus of the plating film on the electrodes E _1, E ₂ are still present, carried out in order to ensure the state nuclear no plating film is removed it to the electrodes E _1, E ₂ It is a thing. Therefore, when the electrodes E ₁ and E ₂ do not have nuclei of such a plating film, cleaning can be omitted. However, it is preferable to perform at least the first initiation operation immediately after the start of the work.

In this case, in the above-mentioned embodiment, the cleaning time was set to about 5 seconds at the set current density 8 A / dm ² , but the set current density and the cleaning time can be variously selected according to the type of bath and the like. Generally, the set current density can be 4 to 20 A / dm ² and the time can be 1 to 120 seconds. If the cleaning time is too short, the nuclei of the plating film on the electrode E ₂ may not be removed sufficiently, which may cause a measurement error and may cause inconvenience. Conversely, if the cleaning time is too long, the plating target This is because such an inconvenience arises that the frequency of appearance on the object is reduced within a predetermined plating time.

Furthermore, in the above-mentioned embodiment, the description has been given with an example in which the communication / control I / F unit is connected to the CPU unit.However, this is because the plating bath is precisely controlled by connecting an automatic liquid management device, which is an external device, to this device. This is for the purpose of controlling and precisely controlling the thickness of the plating film, but the communication / control I / F part may be omitted from the device, and other configurations do not depart from the gist of the invention. Various changes can be made within the range.

(Effects of the Invention) As described above, according to the method of the present invention, the plating deposition rate can be continuously detected in the same bath and the discovery or prediction of abnormal deposition or decomposition of the bath can be achieved by the above-mentioned configuration. Easy and finely controlled bath management. Further, since the plating deposition rate can be measured directly in the electroless plating bath, various preparations such as determination of the coefficient before the start of plating are not required, which is troublesome. Moreover, the time required to dissolve the electrodeposits of the electrode E ₂ deposited during initiation (T ₁ -T ₀ ) while maintaining the electrolysis current value constant, and the film deposited on the electrode E ₂ by electroless plating to determine the time of dissolving the electrolyte (T ₂ -T _0), the plating rate calculating operation to an electroless plating only by the time to dissolve the coating deposited on the electrode E ₂ by electrolysis (T ₂ -T _1), Since the measurement is simple and there are few calculation factors, and the plating rate can be easily calculated to obtain the plating rate, the measurement is simple and there are few calculation factors, so the plating rate can be detected accurately.

Further, according to the device of the present invention, since it is possible to directly measure the plating deposition rate in the plating bath by the above configuration, it is economical without the need to separately prepare an electrolytic bath or the like,
In addition, various preparations such as determination of a coefficient are not required before the start of plating, which does not require any trouble, and since the plating deposition rate can be continuously detected, constant maintenance of physical properties of the plating film can be facilitated. Furthermore, the device according to the invention is
With the above-mentioned structure, the structure is simple and the process can be carried out fully automatically. Therefore, no skill is required, the operation of the device is simple and the operation is easy, and the device can be downsized and manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the device of the present invention, and FIG.
The figure is a time chart of the same example, FIG. 3 is a graph showing the relationship between the energization time and the voltage change in the plating film peeling operation, and FIG. 4 is the relationship between the deposition rate and the plating bath temperature measured by the method of the present invention. FIG. 5 is a flow chart showing the flow of the program of the same example. 1 …… Sensor probe part, 2 …… Sensor interface part, 3 …… CPU part, 8 …… Power supply part, 9 …… Electroless plating bath, 10 …… Voltmeter, E ₁ …… Anode, E ₂ …… Working electrode, E ₃ …… Cathode SW ₁ , SW ₂ , SW ₃ , SW ₄ …… Switch.

Claims (3)

[Claims] 1. A positive electrode in an electroless plating bath (E _1), working electrode (E ₂₎ and the cathode (E ₃₎ was immersed respectively, the working electrode (E ₂₎
As a cathode, a current is passed between the anode (E ₁ ) and the anode (E ₁ ) at a constant current value for a certain time, and a first initiation operation for electrolytically depositing a plating film on the working electrode (E ₂ ) is performed, and immediately thereafter, the plating bath. In this case, the working electrode (E ₂ ) is used as an anode and a current is passed between the working electrode (E ₂ ) and the cathode (E ₃ ) at a constant current value, and the plating film on the working electrode (E ₂ ) is electrolytically eluted to remove the first plating film. When the electrolytic elution is started by the operation of peeling the first plating film by monitoring the electrolytic voltage between the working electrode (E ₂ ) and the cathode (E ₃ ) during the electrolytic elution, (T ₀ ). To the time (T ₁ ) when the voltage rises rapidly (T ₁ −T ₀ )
Then, the working electrode (E ₂ ) is used as a cathode and the anode (E ₁ ) is energized at the same current value as in the initiation operation for the same time to form a plating film on the surface of the working electrode (E ₂ ). performs second initiation operation to electrolytic deposition, immediately thereafter stops the energization between the anode (E ₁₎ and the working electrode (E _2), the current from the stop predetermined time working electrode (E ₂₎ the After leaving it in the plating bath to further electrolessly deposit the plating film on the electrolytically deposited plating film, immediately in the plating bath, the working electrode (E ₂ ) is used as the anode and the cathode (E ₃₎ the plating film peeling operation and energized at the same current value subjected to second plating film peeling operation for electrolytic dissolution of the plating coating on the working electrode (E ₂₎ between,
The electrolytic voltage between the working electrode (E ₂ ) and the cathode (E ₃ ) at the time of electrolytic elution was monitored, and the voltage rapidly increased from the time when electrolytic elution was started by the second plating film peeling operation (T ₀ ). The time (T ₂ −T ₀ ) up to the time of rising (T ₂ ) is measured, and the deposition rate of the electroless plating bath is calculated from the difference (T ₂ −T ₁ ) between the two times. Method for detecting deposition rate of electroless plating. 2. The anode (E ₁ ) before the initiation operation.
And the working electrode (E ₂ ) as the anode (E ₁ ) respectively, and electricity is applied between the cathode (E ₃ ) and the anode (E ₁ ) and the working electrode (E ₂ ).
The method according to claim 1, wherein each of the two is anodically cleaned. 3. A sensor probe unit having an anode (E ₁ ), a working electrode (E ₂ ), and a cathode (E ₃ ), each of which is immersed in an electroless plating bath, and first to fourth switches (SW _{1). ~ 4} ) and a voltmeter, the anode (E ₁ ) and the first switch (S
W ₁ ), the working electrode (E ₂ ), the second switch (SW ₂ ) and the third switch (SW ₃ ), the cathode (E ₃ ) and the fourth switch (S ₃ ).
W ₄ ) is connected to the first to fourth switches (SW
_{1 to 4} ) and a sensor interface part for turning on and off, and an anode terminal for the first and second switches (SW ₁ , S)
W ₂ ), and a cathode terminal connected to the third and fourth switches (SW ₃ , SW ₄ ), a power supply section connected to the sensor interface section, and a voltmeter, Measuring unit for reading a voltage value and the first to fourth
The switches (SW _{1 to} SW ₄ ) are connected to these first to fourth
And a CPU section having a control section for controlling ON / OFF of the switches (SW _{1 to} SW ₄ ), and the CPU section turns on the first and third switches (SW ₁ , SW ₃ ), respectively. The second and fourth switches (SW ₂ , SW ₄ ) are turned off, and a constant current value is applied between the anode (E ₁ ) and the working electrode (E ₂ ) for a certain period of time, and the working electrode (E ₂ ) is fed. A first initiation command function for electrolytically depositing a plating film, and immediately after the completion of this electrolytic deposition, the first and third switches (SW ₁ , SW ₃ ) are turned off and the second and fourth switches (SW ₂ , SW ₃ ) are turned off. ₄ ) is turned on and a constant current value is applied between the working electrode (E ₂ ) and the cathode (E ₃ ),
The first to electrolytically elute the plating film on this working electrode (E ₂ )
The plating film peeling command function and the change in the electrolytic voltage between the working electrode (E ₂ ) and the cathode (E ₃ ) at the time of electrolytic elution measured by the voltmeter of the sensor interface section are monitored,
A function of measuring and storing the time (T ₁ −T ₀ ) from the time when electrolytic elution is started (T ₀ ) to the time when the voltage rises rapidly (T ₁ ) by the first plating film peeling command, and The first and third switches (SW ₁ , SW ₃ ) are turned on, the second and fourth switches (SW ₂ , SW ₄ ) are turned off, and the anode (E
₁ ) and a working electrode (E ₂ ) are energized at the same current value as the first initiation command for the same time, and a second initiation command function of electrolytically depositing a plating film on the working electrode (E ₂ ). Immediately after the completion of this electrolytic deposition, at least the second and third switches (SW ₂ , SW ₃ ) are turned off, and electroless plating is further performed on the plating film electrolytically deposited on the working electrode (E ₂ ) for a predetermined time. The electroless plating command function of depositing a film, and the first film peeling command between the working electrode (E ₂ ) and the cathode (E ₃ ) by turning on the second and fourth switches immediately after the completion of the electroless plating. The second plating film peeling command function of electrolytically eluting the plating film on this working electrode (E ₂ ) by energizing it with the same current value as above, and the working electrode at the time of electrolytic elution measured by the voltmeter of the sensor interface section. (E ₂₎ and between the cathode (E ₃₎ Monitoring the changes in the solution voltages, when the electrolytic elution is started by the second plating film peeling command (T ₀₎
To the time when the voltage rises rapidly (T ₂ ) (T ₂
-T ₀ ) is measured, and the deposition rate of the electroless plating bath is calculated from the difference (T ₂ -T ₁ ) between this time (T ₂ -T ₀ ) and the time (T ₁ -T ₀ ). A deposition rate detection device for electroless plating, which has a function.