KR100934729B1 - Electroless Tin Plating Solution Impurity Removal Apparatus and Method - Google Patents

Abstract

An impurity removing apparatus of an electroless tin plating liquid according to the present invention includes a plurality of compartments continuously arranged to communicate with each other, an impurity removing unit disposed in the compartment and including a positive electrode plate and a negative electrode plate, and a power supply to the impurity removing unit. And a power supply for supplying, wherein the current density of the current supplied from the power supply is 0.05 A / dm 2 or more and 10 A / dm 2 or less. On the other hand, the impurity removal method of the electroless tin plating solution according to the present invention, the step of introducing an electroless tin plating solution into a plurality of compartments that are continuously arranged to be in communication with each other, and disposed in the compartment and comprises a positive electrode plate and a negative electrode plate And passing the electroless tin plating solution through the impurity removing unit, wherein the current density of the current supplied to the impurity removing unit is 0.05 A / dm 2 or more and 10 A / dm 2 or less.

This makes it possible to remove copper ions and antimony in the electroless tin plating solution with a minimum of equipment, and to make it reusable again.

Description

Electroless Tin Plating Solution Impurity Removal Apparatus and Method {APPARATUS AND METHOD OF REMOVING IMPURITIES IN ELECTROLESS TINNING SOLUTION}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impurity removal device and a method thereof, and more particularly, to a removal device and a method for removing impurities in a plating liquid used for electroless plating that does not require the supply of electrical energy.

Electroless plating is also a chemical plating, the plating solution component contains a reducing agent component, the plating method using the principle that the metal is precipitated while the metal is reduced by the reducing agent.

The electroless tin plating solution is an acid plating solution containing thiourea, and is a plating solution for plating for the purpose of preventing oxidation of copper or copper alloy and for improving the soldering characteristics of electronic parts. Electroless tin plating is done.

In this substitutional plating process, copper is dissolved into ions, and the ionized copper component is inevitably dissolved in the plating solution.

On the other hand, to improve the flame retardancy and processability of the PCB substrate, antimony trioxide is added as a component of the PCB substrate, and during the electroless plating process, such antimony trioxide is also dissolved and present as impurities in the plating solution.

This increase of impurities not only shortens the usable life of the plating solution, but also deteriorates the soldering properties by degrading the performance of the plating film and promotes oxidation of the plating surface, thereby causing defects in electronic components.

In particular, the antimony interferes with the reduction of tin, preventing tin plating from proceeding smoothly, and causes a problem that the tin plating film becomes cloudy or not plated.

Accumulation of copper ions in the electroless tin plating solution increases sludge generation due to the decrease in solubility of copper ions and increases the copper content in the electroless plated tin film, resulting in a decrease in soldering properties and the growth rate of intermetallic compounds. There is a problem that reduces the long-term storage of the plated product.

In order to solve this problem, a method of minimizing the inclusion of antimony trioxide in the plating solution has been proposed by introducing a pretreatment step, but this process not only increases the cost including the pretreatment step, There is a problem that is harmful to the environment by using a strong acid.

In addition, the copper ions generated during the plating process has a problem that can not be removed.

Accordingly, the present invention has been made to solve the above problems, it is an object of the present invention to provide an apparatus and method for removing copper ions and antimony ions in an electroless plating solution.

It is yet another object of the present invention to provide an apparatus and method that can remove copper ions and antimony ions in an electroless plating solution and make them reusable again with minimal equipment.

In order to achieve the object of the present invention as described above, the impurity removing device of the electroless tin plating liquid according to the present invention, a plurality of compartments arranged in series to be in communication with each other, and disposed in the compartment comprises a positive electrode plate and a negative electrode plate And an impurity removal unit and a power supply unit for supplying power to the impurity removal unit, wherein the current density of the current supplied from the power supply unit is 0.05 A / dm 2 or more and 10 A / dm 2 or less.

Here, the positive electrode plate may include any one of tin, platinum or titanium.

In addition, the negative electrode plate may include any one of tin, platinum, or titanium.

Preferably, the current density supplied from the said power supply part is 0.1 A / dm <2> or more and 1 A / dm <2> or less.

The electroless tin plating solution replenishing unit may be further included to replenish the electroless tin plating solution into the impurity removing device of the electroless tin plating solution.

In addition, the electroless tin plating solution impurity removal device and the electroless tin plating solution for circulating the electroless tin plating solution between the electroless plating portion may further include a.

On the other hand, the impurity removal method of the electroless tin plating solution according to the present invention, the step of introducing an electroless tin plating solution into a plurality of compartments that are continuously arranged to be in communication with each other, and disposed in the compartment and comprises a positive electrode plate and a negative electrode plate And passing the electroless tin plating solution through the impurity removing unit, wherein the current density of the current supplied to the impurity removing unit is 0.05 A / dm 2 or more and 10 A / dm 2 or less.

Here, the positive electrode plate may include any one of tin, platinum or titanium.

Alternatively, the negative electrode plate may include any one of tin, platinum, or titanium components.

Preferably, the current density of the current supplied to the impurity removing unit may be 0.1 A / dm 2 or more and 1 A / dm 2 or less.

The method may further include an electroless tin plating solution replenishing step for replenishing the electroless tin plating solution into the impurity removing device of the electroless tin plating solution.

In addition, the step of flowing out the electroless tin plating solution to the electroless plating portion may be further included.

According to the present invention, copper ions and antimony ions in the electroless tin plating solution can be effectively removed.

In addition, with minimal equipment, copper ions and antimony in the electroless tin plating solution can be removed and made available again for reuse.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration of the present invention.

Prior to this, the terms used in this specification and claims should not be construed in a dictionary sense, and the inventors may properly define the concept of terms in order to explain their invention in the best way. It should be construed as meaning and concept consistent with the technical spirit of the present invention.

Therefore, the configurations shown in the embodiments and drawings described herein are only preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents may be substituted for them at the time of the present application. It is to be understood that water and variations may exist.

1 is a schematic diagram of an apparatus for removing impurities in an electroless tin plating liquid according to the present invention.

 The impurity removing device of the electroless tin plating liquid according to the present invention includes a plurality of compartments 10 and 12 arranged in series so as to be in communication with each other, and are arranged in the compartments 10 and 12 and have a positive electrode plate 14 and a negative electrode plate ( And a power supply for supplying power to the present impurity removal unit, wherein the current density of the current supplied from the power supply unit is 0.05 A / dm 2 or more and 10 A / dm 2 or less. It is characterized by.

Here, the compartments 10 and 12 are configured to receive the electroless tin plating solution introduced from the electroless plating unit 50 and to remove impurities, and the plurality of compartments 10 and 12 are continuously communicated with each other. Is placed.

Preferably, the electroless tin plating liquid that is an impurity removal target sequentially moves the compartments 10 and 12 in an overflow manner and impurities contained in the plating liquid are removed, but the transfer method is not limited thereto. Or, may be configured to move within the compartments 10, 12 by a variety of methods.

The compartments 10 and 12 are provided with a positive electrode plate and a negative electrode plate for removing copper, antimony ions, and the like contained in the electroless tin plating solution.

Here, the positive electrode plate 14 and the negative electrode plate 16 may be provided as a plate-shaped or ball-shaped member containing tin, platinum or titanium.

The positive electrode plate 14 and the negative electrode plate 16 constitute an impurity removing unit according to the present invention, and by supplying power to the positive electrode plate 14 and the negative electrode plate 16 through the power supply (not shown), the principle of plating To remove impurities such as copper and antimony.

The power supply unit is preferably composed of a rectifier, the current density supplied to the positive electrode plate 14 and the negative electrode plate 16 through the rectifier is in the range of 0.05 A / dm 2 or more and 10 A / dm 2 or less.

There is no limitation in the range of the voltage for supplying the current in the current density range, it is possible to supply the current of the current density by a voltage of various sizes, including a voltage in the range of 30V to 200V.

When the current having the current density range is supplied to the impurity removal unit through the rectifier, ions such as copper and antimony contained in the electroless tin plating solution are reduced to precipitate on the surface of the negative electrode plate 16.

In general, the main components of the metal that can be generated during the PCB surface treatment is copper and antimony, all of which are reduced and precipitated before tin when a low current is applied in the electrolyte solution.

Therefore, by applying the low current to the impurity removal unit using this property, it is possible to precipitate copper and antimony ions as a metal, and ultimately electroless by removing the deposited copper and antimony metal from the electroless tin plating solution. Impurities contained in the tin plating liquid can be removed.

In this case, when the current density is less than 0.05 A / dm 2, impurities such as copper and antimony are reduced and precipitated so that impurities cannot be removed quickly, and the current density exceeds 10 A / dm 2. In this case, the amount of precipitation of tin ions contained in the electroless tin plating solution increases, which leads to a large consumption of tin.

For the same reason as above, the current density is more preferably in the range of 0.1 A / dm 2 or more and 1 A / dm 2 or less.

The electroless tin plating solution that has passed through the plurality of compartments 10 is finally accommodated in the last compartment 12, and the plating solution is replenished from the electroless tin plating solution replenishment unit 30 installed in the last compartment 12. As a result, the content of impurities such as copper and antimony ions in the plating solution is lowered.

Although the electroless tin plating liquid replenishing unit 30 has been described as replenishing the tin plating liquid into the last compartment 12, the present invention is not limited thereto. It may be configured to replenish the electroless tin plating solution.

The electroless tin plating solution in which the content ratio of impurities is reduced as described above is recycled to the electroless plating part 50 by a pipe and a pump 40-1 installed outside the last compartment 12.

Here, the electroless tin plating part and the compartments 10, by the pipe and pump 40-1 installed outside the last compartment 12 and the pipe and pump 40 arranged outside the first compartment 10. 12) The electroless tin plating solution is circulated by the inflow / outflow of the electrolyte.

That is, the tin plating liquid flows into the first compartment 10 from the electroless tin plating unit by a pipe and a pump 40 disposed outside the first compartment 10 and the plurality of compartments 10 and 12. After removing the copper and antimony ions contained in the tin plating solution while passing through them, the plating solution is replenished through the electroless tin plating solution replenishment unit 30 and recycled to the electroless tin plating unit 50.

Next, an embodiment in which copper and antimony ions are removed using an impurity removal device of an electroless tin plating solution according to the present invention will be described.

Current Density (ASD) Hour (hr) Initial Sb Concentration (ppm) Initial Cu Concentration (g / L) Sb concentration in the electrode Cu concentration in the electrode Final Sb Concentration (ppm) Final Cu concentration (g / L) 0.05 12 200 0.5 3% 6% 150 0.4 24 200 0.5 5% 3% 100 0.4 0.10 12 200 0.5 10% 15% 80 0.3 24 200 0.5 8 % 14% 50 0.3 0.50 12 100 0.5 7% 20% 80 0.1 24 100 0.5 8 % 14% 30 0.2 1.00 12 100 0.5 6% 16% 60 0.1 24 100 0.5 5% 18% 30 0.1

Example 1

Referring to Table 1, a current of 0.05 A / dm 2 to 1.00 A / dm 2 current density range of 12 hours or 24 hours without being transferred into a plurality of compartments without being transferred into a plurality of compartments was stored. Was applied to the positive / negative plate.

After the application of the current, the metal film deposited on the positive / negative plate was subjected to component analysis using an electron microscope.

For example, when the current having a current density of 0.05 A / dm 2 was applied for 12 hours, the initial concentration of antimony ion was 200 ppm, and the concentration of copper ion was 0.5 g / L.

After 12 hours, the concentrations of antimony and copper ions in the positive / cathode plates were 3% and 6%, respectively, and the concentrations of antimony and copper ions in the final solution were 150 ppm and 0.4 g / L, respectively.

Therefore, it can be seen that 50 ppm of antimony ions and 0.1 g / L of copper ions decreased.

Example 2

A current density of 0.5 A / dm 2 was applied through the impurity removal device of the electroless tin plating liquid shown in FIG. 1, and the plating liquid was transferred at a feed rate of 10 L per minute.

The initial concentration of antimony ions in the plating solution was 200 ppm, and the concentration of copper ions was 1 g / L.

After 24 hours of impurity removal, about 90% of antimony ions were removed and about 50% of copper ions were removed.

Hereinafter, a method of removing impurities in the electroless tin plating solution according to the present invention will be described.

First, the tin plating liquid transferred from the electroless tin plating unit 50 is introduced into the plurality of compartments 10, and then, in the positive and negative plates disposed in the compartments 10, 0.05 A / dm 2 or more. A current having a current density in the range of A / dm 2 or less, more preferably 0.1 A / dm 2 or more and 1 A / dm 2 or less is applied.

Antimony ions and copper ions contained in the tin plating solution are precipitated and removed on the positive / negative electrode while passing through the plurality of compartments 10 to which current in the current density range is applied.

 Thereafter, the electroless tin plating solution replenishment unit 30 is replenished by the electroless tin plating solution replenishing unit 30 in the final compartment 12 and finally flows out to the electroless tin plating unit 50 to be circulated.

As mentioned above, although the present invention has been described by way of limited embodiments and drawings, the technical idea of the present invention is not limited thereto, and a person having ordinary skill in the art to which the present invention pertains, Various modifications and variations may be made without departing from the scope of the appended claims.

Since the accompanying drawings are for understanding the technical spirit of the present invention together with the detailed description of the following invention, the present invention should not be construed as limited to the matters shown in the following drawings.

1 is a schematic diagram of an apparatus for removing impurities in an electroless tin plating liquid according to the present invention.

Explanation of symbols on the main parts of the drawings

10: compartment 14: bipolar plate

16: negative electrode plate 30: electroless tin plating solution

40, 40-1: circulating electroless tin plating solution

Claims (12)

A plurality of compartments continuously arranged to communicate with each other; An impurity removal unit disposed in each of the compartments and including a positive electrode plate and a negative electrode plate; An impurity removal device of an electroless tin plating solution including a power supply unit for supplying power to the impurity removal unit. The positive electrode plate and the negative electrode plate includes any one of tin or platinum or titanium, The current density of the current supplied from the power supply is 0.05 A / dm 2 or more and 10 A / dm 2 or less, An electroless tin plating solution replenishment unit for replenishing the electroless tin plating solution into the impurity removing apparatus of the electroless tin plating solution; An electroless tin plating solution circulating unit for circulating the electroless tin plating solution between the electroless tin plating solution impurity removing device and the electroless plating unit, The electroless tin plating liquid is impurity removal device of the electroless tin plating liquid, characterized in that the impurities are removed while moving a plurality of compartments arranged in series to communicate with each other. delete delete The method of claim 1, The current density supplied from the power supply unit, An impurity removal device for an electroless tin plating solution, characterized in that not more than 0.1 A / dm 2 or less than 1 A / dm 2. delete delete Introducing an electroless tin plating solution into a plurality of compartments continuously arranged to communicate with each other; A method of removing impurities in an electroless tin plating solution, comprising: passing the electroless tin plating solution through an impurity removal unit disposed in each of the compartments and including an anode plate and a cathode plate. The positive electrode plate and the negative electrode plate includes any one of tin or platinum or titanium, The current density of the current supplied to the impurity removal unit is 0.05 A / dm 2 or more and 10 A / dm 2 or less, The impurity removing method of the electroless tin plating liquid may include: an electroless tin plating liquid replenishing step for replenishing the electroless tin plating liquid into an impurity removing apparatus of the electroless tin plating liquid; Further including the step of flowing out the electroless tin plating solution to the electroless plating portion,  And the electroless tin plating liquid is removed from impurities of the electroless tin plating liquid by moving a plurality of compartments arranged in series so as to communicate with each other. delete delete The method of claim 7, wherein The current density of the current supplied to the impurity removing unit is A method for removing impurities in an electroless tin plating solution, characterized in that not less than 0.1 A / dm 2 or less than 1 A / dm 2. delete delete

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