JP2014034691A - Recycling method and apparatus of plating solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recycling method and apparatus of a plating solution in which handling is made easy, an impurity or the like included in the plating solution after use can be removed, and the plating solution can be efficiently recovered.SOLUTION: A recycling method includes: an active carbon treatment process in which an organic compound included in a plating solution after use is removed by active carbon; an acid concentration adjustment process in which a free acid concentration of the plating solution after use is reduced; an analysis process in which a plating solution component in the plating solution after processing that has undergone the active carbon treatment process and the acid concentration adjustment process is analysed; and a component adjustment process in which a plating solution component is added to the plating solution after processing reaching a prescribed analysis value on the basis of an analysis value by the analysis process, and thereby the plating solution is recovered, wherein the acid concentration adjustment process includes an ion exchange process in which an acid concentration in the plating solution after use is reduced by causing the plating solution after use to be subjected to liquid passing in an anion exchange resin, or a concentration difference of a solution that pinches the anion-exchange membrane by a diffusion dialysis method using an anion-exchange membrane.

Description

  The present invention relates to a plating solution recycling method and apparatus capable of recycling a plating solution used for plating treatment.

  The plating solution used for the electrolytic plating is used until a predetermined electrolytic amount is reached by the plating treatment, and the plating solution after use is treated as a waste solution. The treatment cost of this waste liquid is high, and the burden on the environment is increased by treating a large amount of waste liquid. Moreover, the cost for the liquid exchange was also large for the plating apparatus.

  In addition, as disclosed in Patent Document 1 or Patent Document 2, together with a system for replenishing metal components consumed by plating, the plating solution attached to the object to be plated (plating material) and taken out of the plating tank is collected. Therefore, a plating apparatus having a function of reusing it has been considered, and conventionally, recycling of the plating solution has been studied.

JP 2004-131767 A Japanese Patent Application Laid-Open No. 11-1000069

  The plating solution after use is subjected to electroplating treatment, and organic impurities are mixed (resist dissolution, etc.) and free acid concentration is high. In that respect, Patent Document 1 or Patent Document 2 also removes organic impurities and the like contained in the plating solution by providing a cleaning tank. However, since the free acid concentration is increased by electroplating, it cannot be reused as it is. Therefore, after reducing the free acid concentration in the solution by diluting with a large amount of solution, it is necessary to add plating solution components such as metal components and additives consumed from the plating solution. Since the amount is enormous, handling was poor.

  The present invention has been made in view of such circumstances, can easily handle, remove impurities contained in the plating solution after use, and efficiently regenerate the plating solution. An object of the present invention is to provide a plating solution recycling method and apparatus that can perform the above process.

  The present invention relates to a method for recycling a plating solution for regenerating a post-use plating solution in which the free acid concentration in the plating solution has reached a predetermined value in accordance with the electrolytic plating treatment, and the organic substances contained in the post-use plating solution are activated carbon. Activated carbon treatment step to be removed by the step, an acid concentration adjustment step for reducing the free acid concentration of the post-use plating solution, and a plating solution component in the plating solution after treatment that has undergone the activated carbon treatment step and the acid concentration adjustment step. An acid concentration adjusting step, comprising: an analyzing step; and a component adjusting step of regenerating the plating solution by adding a plating solution component to the post-treatment plating solution that has reached a predetermined analysis value based on an analysis value obtained by the analyzing step. The above-mentioned plating solution is passed through an anion exchange resin, or by diffusion dialysis using an anion exchange membrane, using the difference in concentration of the solution sandwiching the anion exchange membrane, Characterized in that it is constituted by an ion exchange process to reduce the acid concentration in Yogo plating solution.

  By removing the organic substances in the plating solution after use by an activated carbon treatment process using activated carbon, impurities contained in the plating solution can be wiped out. Moreover, the free acid concentration can be reduced without diluting the plating solution after use with a solution by an ion exchange process using an anion exchange resin or using an anion exchange membrane. Because the plating solution component in the treated plating solution processed in this way is analyzed, and the plating solution component that is insufficient in the treated plating solution that has reached the predetermined analysis value is added to regenerate the plating solution. Can be easily handled with small equipment.

In the plating solution recycling method of the present invention, the activated carbon treatment step may be performed before the ion exchange step.
If the ion exchange step is performed prior to the activated carbon treatment step, only some organic components in the plating solution are adsorbed on the surface of the ion exchange resin, etc., and the stability of the plating solution is impaired, resulting in turbidity of the solution. There is a fear. Therefore, it is preferable to perform the ion exchange step after removing impurities by the activated carbon treatment step.

  The present invention is a plating solution recycling apparatus for regenerating a plating solution after use in which the free acid concentration in the plating solution has reached a predetermined value in accordance with the electrolytic plating treatment, and the organic substances contained in the plating solution after use are activated carbon. Activated carbon treatment means to be removed by the above, an acid concentration adjusting means for reducing the free acid concentration of the post-use plating solution, and a plating solution component in the plating solution after treatment that has passed through the activated carbon treatment means and the acid concentration adjusting means. Analyzing means; and component adjusting means for regenerating the plating solution by adding a plating solution component to the post-treatment plating solution that has reached a predetermined analysis value based on the analysis value by the analysis means, and the acid concentration adjusting means The above-mentioned plating solution is passed through an anion exchange resin, or by diffusion dialysis using an anion exchange membrane, using the difference in concentration of the solution sandwiching the anion exchange membrane, Characterized in that it is constituted by ion exchange means for reducing the acid concentration in Yogo plating solution.

  According to the present invention, by reducing the free acid concentration of the plating solution after use without diluting with the solution, the plating solution can be easily handled and the plating solution can be efficiently regenerated.

1 is an overall configuration diagram illustrating a plating apparatus including a plating solution recycling apparatus according to an embodiment of the present invention. It is a figure explaining the ion exchange means by a diffusion dialysis method.

Embodiments of a plating solution recycling method and a recycling apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 shows an overall configuration diagram of a plating apparatus provided with a plating solution recycling apparatus according to an embodiment of the present invention.
The plating apparatus 100 includes a plating tank 1 that performs a plating process by electrolytic plating on an object to be plated, and a recycling apparatus 3 that regenerates a post-use plating solution used for the plating process.
A plating solution is supplied into the plating tank 1, and the object to be plated is plated by electrolytic plating. The plating tank 1 is provided with an analyzing means 2 for analyzing the plating solution component in the plating tank 1.

  The recycling apparatus 3 includes a collection tank 6 for storing the plating solution after use, activated carbon treatment means 4 for removing organic substances contained in the plating solution after use with activated carbon, and an acid concentration for reducing the free acid concentration of the plating solution after use. The analysis means 7 for analyzing the plating solution components in the plating solution after the treatment through the adjustment means 5, the activated carbon treatment means 4 and the acid concentration adjustment means 5, and a predetermined analysis value is reached based on the analysis value by the analysis means 7. And a component adjusting means 8 for regenerating the plating solution by adding a plating solution component to the post-treatment plating solution.

The activated carbon treatment means 4 is composed of a column filled with activated carbon, and adsorbs and removes organic components in the plating solution by bringing the plating solution into contact with the activated carbon. As the activated carbon that adsorbs organic components, those using charcoal as a raw material are preferable, and for example, BA-50 manufactured by Ajinomoto Co., Inc. can be used.
The acid concentration adjusting means 5 is an ion exchange means 5A constituted by a column filled with an anion exchange resin. By plating the post-use plating solution through the anion exchange resin in the column, the post-use plating is performed. The free acid concentration in the liquid can be reduced. As the anion exchange resin, for example, A860OH manufactured by Purolite can be used.
As will be described later, the analysis means 7 measures the concentration of the plating solution components (Sn, Ag, free acid, organic impurities, etc.) contained in the post-treatment plating solution. The component adjusting means 8 adjusts the components by supplying a plating solution component to the post-treatment plating solution based on the analysis value obtained by the analyzing means 7.
In addition, the codes | symbols 12 and 13 shown in FIG. 1 are the valves which open and close the flow in the piping arrange | positioned between the plating tank 1 and the collection tank 6. FIG.

Next, a method for regenerating the plating solution using the recycling apparatus 3 configured as described above will be described.
Sn-Ag alloy plating solutions include acids such as alkyl sulfonic acids such as methanesulfonic acid and ethanesulfonic acid, plating metal ions (Sn ²⁺ , Ag ⁺ ), and additives such as antioxidants and surfactants. , Complexing agents and the like are blended. Then, by subjecting the object to be plated to electrolytic plating, Sn ions and Ag ions in the plating solution in the plating tank 1 are deposited on the surface of the object to be plated as Sn-Ag alloy, and Sn ions and Ag in the plating solution are deposited. The concentration of ions decreases and the free acid concentration increases. When electrolysis progresses and the free acid concentration rises above a predetermined value, the quality of the plating film is impaired. For example, when the free acid concentration reaches 300 g / L, the plating process is terminated.

The plating solution after use may contain organic impurities such as contamination due to electrolysis and resist dissolution, and the free acid concentration is high, so the plating solution before use (new solution) Compared with, the plating property (plating quality) is lowered.
Therefore, as described above, when the free acid concentration in the plating solution in the plating tank 1 reaches a predetermined value as a result of the electrolytic plating treatment, the plating treatment is terminated, and the plating solution after use is moved to the recycling device 3. Then, reproduction processing is performed.

  The post-use plating solution is introduced into the collection tank 6 of the recycling apparatus 3. Then, the post-use plating solution introduced into the collection tank 6 is first brought into contact with the activated carbon by the activated carbon treatment means 4 to remove organic substances containing impurities (activated carbon treatment step). The plating solution from which the organic matter has been removed is returned to the collection tank 6 after the acid concentration is reduced by the ion exchange means 5A (ion exchange step). In the collection tank 6, the analysis of the plating solution component is performed by the analysis means 7 (analysis process), and the plating solution is activated carbon treatment means 4, ion exchange means 5A, collection tank until a predetermined analysis value is reached based on the analysis value. As the impurities in the plating solution are wiped out, the free acid concentration is reduced. The post-treatment plating solution that has reached a predetermined analysis value is mixed with a plating solution component such as a metal component or an additive by the component adjusting means 8 to adjust the component (component adjusting step), and then again in the plating tank 1. Used for plating process.

  Although not shown in FIG. 1, waste liquid discharged when the plating target after the plating process is taken out from the plating tank 1 and cleaned is also introduced into the recovery tank 6. The waste liquid is mixed with the plating solution after use in the collection tank 6 and recycled.

The plating solution recycling apparatus of the present invention may be configured to use ion exchange means 5B by diffusion dialysis using an anion exchange membrane, as shown in FIG.
This ion exchange means 5B reduces the acid concentration in the plating solution after use by utilizing the difference in concentration of the solution sandwiching the anion exchange membrane 50. As shown in FIG. Since the anion exchange membrane 50 is provided perpendicularly to the position, the inside of the dialysis tank 51 is partitioned and used in the left chamber 52 and the right chamber 53 partitioned with the anion exchange membrane 50 interposed therebetween. The post-plating solution and water are respectively passed through. In FIG. 2, the plating solution after use is passed through the left chamber 52 and water is passed through the right chamber 53. In the post-use plating solution having an acid concentration higher than that of water, the free acid in the post-use plating solution moves to the adjacent right chamber 53 through the anion exchange membrane 50. Therefore, the free acid concentration in the plating solution after use can be reduced. As the anion exchange membrane 50, for example, Selemion manufactured by Asahi Glass Co., Ltd. can be used.

  Thus, the impurities contained in the plating solution can be wiped out by removing the organic matter in the plating solution after use by the activated carbon treatment step using activated carbon. Moreover, the free acid concentration can be reduced without diluting the plating solution after use with the solution by the ion exchange process using the anion exchange resin or using the anion exchange membrane 50. Because the plating solution component in the treated plating solution processed in this way is analyzed, and the plating solution component that is insufficient in the treated plating solution that has reached the predetermined analysis value is added to regenerate the plating solution. Can be easily handled with small equipment.

By the way, in the said embodiment, it was set as the structure which arrange | positions the acid concentration adjustment means 5 (ion exchange means 5A, 5B) after the activated carbon treatment means 4, However, The structure which provides the acid concentration adjustment means 5 before the activated carbon treatment means 4 It is good.
If the ion exchange step is performed prior to the activated carbon treatment step, only some organic components in the plating solution are adsorbed on the surface of the ion exchange resin, etc., and the stability of the plating solution is impaired, resulting in turbidity of the solution. There is a fear. Therefore, it is preferable to perform the ion exchange step after removing impurities by the activated carbon treatment step.

The effect of the present invention was verified using the post-use plating solution used for the plating treatment.
In each step, the verification was performed by taking out 1 L of the plating solution into a container and checking the components of the plating solution.

“New solution” in Table 1 indicates the composition of the plating solution before the plating treatment. Note that TS-SLG manufactured by Mitsubishi Materials was used as the complexing agent, and TS-202AD manufactured by Mitsubishi Materials was used as the additive. As a plating process, a plating wafer bath temperature was set to 25 ° C. on a resist-patterned Si wafer, and an electrolysis amount of about 100 AH / L was applied at a current density (ASD) of 12 A / dm ² . .
The “activated carbon treatment step” was performed by adding 100 g of activated carbon into 1 L of the post-use plating solution taken out of the container, stirring for 2 hours, and then filtering. The “ion exchange step” was performed by passing the plating solution after the activated carbon treatment step through a column packed with 200 g of ion exchange resin.
And after each process, the density | concentration analysis of each component in a plating solution was implemented as follows. For Sn ²⁺ , after adding hydrochloric acid and tartaric acid to prevent hydrolysis of Sn, a method of quickly titrating with an iodine standard solution using a starch solution as an indicator in a carbon dioxide generating atmosphere by adding sodium hydrogen carbonate was used. . For Ag ⁺ , absorbance was measured at a wavelength of 328.068 nm using ICP, and Ag was quantified using a calibration curve. The free acid concentration was measured by neutralization titration with 1 mol / L sodium hydroxide solution. The complexing agent and additive were quantified by measuring a specific peak using the HPLC method. Moreover, about the organic impurity, the presence or absence of the impurity was judged by the presence or absence of the peak different from a new liquid in HPLC method.
In addition, the “component adjustment step” was performed by adding a deficient metal element solution, complexing agent, and additive to the plating solution after the ion exchange step so that the same liquid component as the new solution was obtained. . Table 1 shows the results.

As shown in Table 1, post-use plating is performed by applying an activated carbon treatment step to the post-use plating solution in which the Sn component concentration (Sn ²⁺ ) in the plating solution decreases and the free acid concentration increases with the plating treatment. Impurities (organic impurities), which are organic components, are removed together with the complexing agent and additives from the liquid. Moreover, a free acid density | concentration can be reduced by giving an ion exchange process to the plating solution after an activated carbon treatment process. And, after using the activated carbon treatment process and the ion exchange process, the plating solution after use is brought into a new solution state by adding insufficient metal element solution, complexing agent and additives to adjust the components. It was confirmed that the plating solution can be regenerated by the recycling method of the present invention. When plating was performed using the regenerated plating solution, the same plating properties as the new solution could be secured.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the present invention can be applied to a pure Sn plating solution other than the Sn-Ag alloy plating solution described above and a plating solution of Sn-Cu alloy.

DESCRIPTION OF SYMBOLS 1 Plating tank 2 Analyzing means 3 Recycling apparatus 4 Activated carbon processing means 5 Acid concentration adjusting means 5A, 5B Ion exchange means 6 Recovery tank 7 Analyzing means 8 Component adjusting means 50 Anion exchange membrane 51 Dialysis tank 52 Left chamber 53 Right chamber 100 Plating apparatus

Claims (3)

  A plating solution recycling method for regenerating a plating solution after use in which the free acid concentration in the plating solution has reached a predetermined value in accordance with an electrolytic plating treatment, wherein activated carbon removes organic substances contained in the plating solution after use with activated carbon. A treatment step, an acid concentration adjustment step for reducing the free acid concentration of the post-use plating solution, an analysis step for analyzing the plating solution component in the post-treatment plating solution that has undergone the activated carbon treatment step and the acid concentration adjustment step, A component adjustment step of regenerating the plating solution by adding a plating solution component to the post-treatment plating solution that has reached a predetermined analysis value based on the analysis value by the analysis step, and the acid concentration adjustment step is the use A post-plating solution is passed through an anion exchange resin, or a diffusion dialysis method using an anion exchange membrane, and the post-use plating is performed using the difference in concentration of the solution sandwiching the anion exchange membrane. Recycling method of the plating solution, characterized in that it is constituted by an ion exchange process to reduce the acid concentration in the liquid.   The plating method recycling method according to claim 1, wherein the activated carbon treatment step is performed before the ion exchange step.   A plating solution recycling apparatus for regenerating a plating solution after use in which the free acid concentration in the plating solution has reached a predetermined value in accordance with the electrolytic plating treatment, wherein activated carbon removes organic substances contained in the plating solution after use with activated carbon. A treatment means, an acid concentration adjusting means for reducing the free acid concentration of the post-use plating solution, an analysis means for analyzing a plating solution component in the plating solution after the treatment that has passed through the activated carbon treatment means and the acid concentration adjusting means, Component adjusting means for regenerating the plating solution by adding a plating solution component to the post-treatment plating solution that has reached a predetermined analysis value based on the analysis value by the analysis means, and the acid concentration adjusting means is the use A post-plating solution is passed through an anion exchange resin, or a diffusion dialysis method using an anion exchange membrane, and the post-use plating is performed using the difference in concentration of the solution sandwiching the anion exchange membrane. Plating solution recycling apparatus, characterized in that it is constituted by ion exchange means for reducing the acid concentration in the liquid.

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