JP2003293197A - Method for controlling plating bath - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling a plating bath by which organic compounds in the plating bath can be decomposed by a simple method without exerting an adverse effect upon plating performance. <P>SOLUTION: At least one kind of oxidized halide selected from the group consisting of hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, hypobromic acid, hypoiodous acid, iodous acid, iodic acid, periodic acid and their salts is added, so that organic compounds in the plating bath are decomposed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for preparing a plating bath which decomposes organic components in the plating bath by chemical oxidation treatment.

[0002]

2. Description of the Related Art Various organic components are added to a plating bath for decorative purposes and for improving film characteristics. Since these organic components are consumed with use, they are continuously replenished and used.However, excessive addition of organic components, abnormal balance, accumulation of decomposition products, etc. may have a serious adverse effect on the above purpose. .

In such a case, a method of forcibly oxidizing and decomposing the organic component by adding an oxidizing agent such as hydrogen peroxide or permanganate to the plating bath, or a method of adsorbing and removing the unnecessary organic component by treatment with activated carbon. , A combination of these methods has been used.

Among these methods, the activated carbon treatment is a reliable method, but since it has poor workability, in the case of a slight adverse effect, the treatment by only adding an oxidizing agent is generally performed.

However, in the above-mentioned conventional oxidizer, the oxidizer not consumed in the oxidative decomposition of the organic component remains in the plating bath and adversely affects the plating performance, so that the remaining oxidizer is completely decomposed. For the purpose, long-term electrolytic treatment was required.

[0006]

The main object of the present invention is to:
It is an object of the present invention to provide a plating bath adjusting method capable of decomposing organic components in a plating bath by a simple method without adversely affecting the plating performance.

[0007]

The present inventor has conducted extensive studies in order to solve the above-mentioned problems of the prior art. As a result, by using an oxide halide as an oxidant and adding it to the plating bath, the organic compound contained in the plating bath can be rapidly decomposed, and the oxidant can be rapidly self-deposited. We found that the decomposition does not adversely affect plating,
The present invention has been completed here.

That is, the present invention provides the following plating bath adjusting method.

1. A method for preparing a plating bath, which comprises adding an oxide halide to the plating bath to oxidatively decompose an organic compound contained in the plating bath.

2. Oxidized halides are hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromic acid, bromic acid, bromic acid, perbromic acid, hypoiodic acid, iodic acid, iodic acid, Item 2. The method for preparing a plating bath according to Item 1, which is at least one selected from the group consisting of iodic acid and salts thereof.

3. 3. The method for preparing a plating bath according to the above item 1 or 2, wherein the plating bath is an acidic electroplating bath or an acidic electroless plating bath.

4. 4. The method for preparing a plating bath according to the above item 3, wherein the plating bath is a copper sulfate plating bath and the component to be decomposed is a sulfur-containing organic compound.

5. Hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromic acid, bromic acid, bromic acid, perbromic acid, hypoiodic acid, iodic acid, iodic acid, periodic acid, and these An organic compound decomposing agent in a plating bath containing as an active ingredient at least one kind of oxide halide selected from the group consisting of salts of

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The method for adjusting a plating bath of the present invention is
The method is characterized in that an oxide halide is added to a plating bath to oxidatively decompose an organic compound contained in the plating bath. In this method, it is important to use an oxide halide as an oxidizing agent for the organic compound contained in the plating bath. Oxide halides show a strong oxidizing power and fast-acting effect on organic compounds by instantly releasing active oxygen in the plating bath. Since it does not remain in the plating bath, it is an excellent oxidizing agent in that it does not adversely affect the plating bath.

In the method for adjusting the plating bath of the present invention, the plating bath to be treated is not particularly limited, and the method of the present invention can be applied to various electroplating baths and electroless plating baths.

Specific examples of the electroplating bath to be treated include a copper plating bath, a nickel plating bath, a zinc plating bath,
Tin plating bath, precious metal plating (gold, silver, ruthenium, rhodium, palladium, osmium, iridium, platinum)
Baths, their alloy plating baths, etc. can be mentioned. The type of specific electroplating bath is not particularly limited, and the method of the present invention can be applied to well-known plating baths of various compositions.

As a specific example of the electroless plating bath,
Examples thereof include a copper plating bath, a nickel plating bath, a gold plating bath, a silver plating bath, and a palladium plating bath. The type of specific electroless plating bath is not particularly limited, and the method of the present invention can be applied to known plating baths of various compositions.

In the present invention, of the various plating baths described above, particularly when an acidic plating bath is to be treated, the organic compound contained in the plating bath can be decomposed and removed efficiently. It is advantageous.

Further, in the method of the present invention, particularly when a copper sulfate plating bath is to be treated, a sulfur-containing organic compound to be added as a brightening agent is selected from the components contained in the plating bath. It can be oxidatively decomposed. In general,
In the copper sulfate plating bath, the adverse effects of the additive are often due to excess or deficiency of the sulfur-containing organic compound, changes with time of the sulfur-containing organic compound, and the like. According to the method of the present invention, the sulfur-containing organic compound can be selectively oxidatively decomposed. Therefore, after the treatment by the method of the present invention, if necessary,
By adding the sulfur-containing organic compound, the copper sulfate plating bath can be adjusted to a good state. Therefore, the method of the present invention is particularly useful as a method for adjusting the copper sulfate plating bath.

When the method of the present invention is applied to a copper sulfate plating bath, the composition of the copper sulfate plating bath is not particularly limited, and various commonly used copper sulfate plating baths may be treated. it can. The specific composition includes copper sulfate (pentahydrate): about 10 to 300 g / l, sulfuric acid: about 10 to 300 g / l, chloride ion: about 20 to 120 mg / l, and further a brightener and a leveling agent. Examples thereof include those containing various additives such as polymer compounds. In such a copper sulfate plating bath, a sulfur-containing organic compound is usually added as a brightening agent, and specific examples thereof include 3-mercaptopropylsulfonic acid, its sodium salt, and bis (3-sulfopropyl) disulfide. , Its 2 sodium salt, N, N-dimethyldithiocarbamic acid (3-sulfopropyl) ester,
The sodium salt etc. can be mentioned. When the adjustment method of the present invention is applied to a copper sulfate plating bath, sulfur-containing organic compounds added as these brighteners and various sulfur-containing organic compounds produced by the change with time of the brighteners are selectively selected. Can be oxidatively decomposed.

In the adjusting method of the present invention, as the oxidic halide, for example, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromic acid, bromic acid, bromic acid, perbromic acid, It is possible to use iodic acid, iodic acid, iodic acid, periodic acid, salts of these acids, and the like. The type of salt is not particularly limited as long as it is soluble in the plating bath, and for example, alkali metal salts such as sodium salt and potassium salt can be used. These oxide halides can be used alone or in combination of two or more.

Examples of preferred oxyhalides include:
Sodium hypochlorite, calcium hypochlorite, sodium chlorite, sodium chlorate, potassium chlorate, perchloric acid, sodium perchlorate, potassium perchlorate, sodium bromate, potassium bromate, sodium iodate ,
Examples thereof include potassium iodate, periodate, sodium periodate, potassium periodate and the like.

In the adjusting method of the present invention, the above-mentioned oxide halide may be added to the plating bath to be treated and stirred as necessary. The oxide halide is usually added to the plating bath after the completion of plating, but it may be added during plating to adjust the amount of organic compounds simultaneously with the plating treatment.

The amount of the oxide halide added is not particularly limited and may be appropriately determined according to the type and amount of the organic compound contained in the plating bath. For example, when the adjustment method of the present invention is applied to a copper sulfate plating bath, the amount of sulfur-containing organic compound generally contained in the copper sulfate plating bath is
It is about 0.001 to 1 mmol / l, and in order to oxidatively decompose the sulfur-containing organic compound in this range, the concentration of the oxyhalide in the plating bath may be set to about 0.001 to 10 mmol / l. The specific addition amount may be appropriately determined according to the amount. However, if the amount of the oxide halide is excessive, the halogen concentration in the copper sulfate plating bath may increase, which may hinder the plating.

The method for adding the oxide halide to the plating bath is not particularly limited, and the oxide halide may be added as it is, or may be added as an appropriate diluted solution. However, since the halogenated oxide self-decomposes rapidly in the plating bath, if the entire amount is added to a part of the plating bath, it decomposes in a short time and only the organic compounds present in a part of the plating bath are oxidatively decomposed. Sometimes. For this reason, it is preferable that the oxide halide is dispersed and added to each part of the plating bath, and it is particularly preferable to add it as a dilute solution.

The treatment time with the oxide halide varies depending on the type and amount of the organic compound contained in the plating bath and the type and amount of the oxide halide used, and therefore cannot be determined unconditionally. 30 seconds to 30
It may be set within the range of about a minute. The plating bath temperature during the treatment with the oxide halide is not particularly limited, but if the liquid temperature is too high, the decomposition of the oxide halide may proceed rapidly and only some organic compounds may be decomposed. If the liquid temperature is too low, the decomposition of organic compounds may be insufficient. Therefore, the liquid temperature is usually about 10 to 60 ° C.

By adjusting the plating bath by the above method, the organic compound contained in the plating bath can be oxidatively decomposed. In addition, the oxidized halide does not remain in the plating bath in a state of having oxidizing power because it self-decomposes rapidly, and does not require a long-term electrolytic treatment after addition of an oxidant as in the conventional method. Therefore, after the treatment by the method of the present invention, the plating bath can be adjusted to a good state by adding an additive component to the plating bath, if necessary.

Particularly, when the preparation method of the present invention is applied to a copper sulfate plating bath, the sulfur-containing organic compound can be selectively oxidatively decomposed, so that the amount of the sulfur-containing organic compound used as the brightener is When the amount becomes excessive, the amount can be reduced, and also when a change with time of the brightener component is accumulated, it can be decomposed and removed.
Therefore, after treating the copper sulfate plating bath with the method of the present invention, the copper sulfate plating bath can be adjusted to a good state by adding a brightening agent if necessary.

[0029]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 Copper sulfate (pentahydrate) 200 g / l, sulfuric acid 50 g / l, chloride ion 70 mg / l
l, polyethylene glycol (average molecular weight 2000) 0.5g /
l, diethylsafranine 5 mg / l, sodium mercaptopropane sulfonate 5 mg / l in decorative copper sulfate plating bath, sodium hypochlorite 0.5 mmo as oxidation halide
l / l (37 mg / l) was added, and the mixture was stirred at a liquid temperature of 25 ° C for 10 minutes.

With respect to the copper sulfate plating bath after the above-mentioned treatment, a Hull cell test was carried out for 5 minutes under air stirring under the conditions of a liquid temperature of 25 ° C. and a current of 2 A, and the Hull cell appearance was confirmed.

As a result, the Hull cell appearance was consistent with the matte appearance when no sodium mercaptopropane sulfonate was added to the bath. In addition, when 5 mg / l of sodium mercaptopropane sulfonate was added to this plating bath, the initial state (state before addition of oxide halide)
It returned to a uniform glossy appearance similar to.

From the above results, it was confirmed that only sodium mercaptopropanesulfonate was selectively oxidized and decomposed by adding sodium hypochlorite to the copper sulfate plating bath.

Example 2 Copper sulfate (pentahydrate) 70 g / l, sulfuric acid 200 g / l, chloride ion 50 mg / l
l, polyoxyethylene polyoxypropylene ether (average molecular weight 4000) 0.2g / l, bis (3-sulfopropyl) disulfide disodium 2mg / l, triethylene tetramine 1mg / l copper sulfate plating bath for printed wiring boards Potassium bromate 0.1 mmol / l (1
7 mg / l) was added, and the mixture was stirred at a liquid temperature of 20 ° C for 1 minute. afterwards,
A Hull cell test was conducted under the same conditions as in Example 1, and the Hull cell appearance was confirmed.

As a result, the Hull cell appearance was consistent with the matte appearance when no bis (3-sulfopropyl) disulfide disodium was added to the bath. When 2 mg / l of bis (3-sulfopropyl) disulfide disodium was added to this plating bath, the same glossy appearance as in the initial state (state before addition of oxide halide) was restored.

From the above results, it was confirmed that by adding potassium bromate to the copper sulfate plating bath, only bis (3-sulfopropyl) disulfide disodium was selectively oxidized and decomposed.

Example 3 Copper sulfate (pentahydrate) 230 g / l, sulfuric acid 60 g / l, chloride ion 100 mg / l
l, polyoxyethylene naphthol ether (average molecular weight 1000) 1 g / l, N, N-dimethyldithiocarbamic acid (3-
Sulfopropyl) ester 10 mg / l, ethylene thiourea 1 m
Periodic acid 0.3 mmol / l (58 mg / l) was added as an oxide halide to an electroforming copper sulfate plating bath consisting of g / l, and the liquid temperature was 4
The mixture was stirred at 5 ° C for 5 minutes. Then, a Hull cell test was conducted under the same conditions as in Example 1 to confirm the appearance of the Hull cell.

As a result, the appearance of Halsel was N, N in the above bath.
-Dimethyldithiocarbamic acid (3-sulfopropyl)
Consistent with the matte appearance when only the ester was not added. In addition, when 10 mg / l of N, N-dimethyldithiocarbamic acid (3-sulfopropyl) ester was added to this plating bath, the initial state (state before addition of oxide halide)
It returned to a uniform glossy appearance similar to.

From the above results, it was confirmed that by adding periodic acid to the copper sulfate plating bath, only N, N-dimethyldithiocarbamic acid (3-sulfopropyl) ester was selectively oxidatively decomposed. .

Comparative Example 1 0.2 mmol / l (32 mg / l) of potassium permanganate was added to the decorative copper sulfate plating bath used in Example 1, and the bath state after stirring for 1 hour at a liquid temperature of 25 ° C. and the Hull cell The appearance was confirmed. The Hull cell test was performed under the same conditions as in Example 1. In the bath state, a reddish purple coloration was observed, indicating the residual of permanganate ion.

The Hull cell appearance was consistent with the matte appearance when only sodium mercaptopropane sulfonate was not added, but even when 5 mg / l sodium mercaptopropane sulfonate was added to this plating bath, the initial glossy appearance was obtained. I didn't recover.

Comparative Example 2 3 mmol / l hydrogen peroxide (0.3 g / l as 35% hydrogen peroxide solution) was added to the copper sulfate plating bath for printed wiring boards used in Example 2, and the solution was heated at 25 ° C. for 30 minutes. The appearance of the Hull cell after stirring for 1 minute was confirmed. The Hull cell test was performed under the same conditions as in Example 1. As a result, the Hull cell appearance is bis (3-sulfopropyl).
It had a semi-glossy appearance showing a slight amount of disodium disulphide remaining.

Bis (3-sulfopropyl) disulfide disodium (2 mg / l) was added to this plating solution, and the effect of residual hydrogen peroxide was confirmed with a semi-glossy appearance.

Further, this plating solution is electrolytically treated (25 ° C., 0.
After 5 A / dm ² , 0.2 A / l, 2 hours), bis (3-sulfopropyl) disulfide disodium 2 mg / l was added,
The uniform gloss Hull cell appearance similar to the initial state was restored.

[0045]

According to the method for adjusting the plating bath of the present invention,
By adding an oxide halide in the plating bath,
The organic compound in the plating bath can be rapidly decomposed. Further, since the oxide halide has a high self-decomposition rate in the plating bath, it does not adversely affect the plating performance.

In particular, when the preparation method of the present invention is applied to a copper sulfate plating bath, the sulfur-containing organic compound can be selectively oxidatively decomposed, which is highly useful.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuka Iwamoto             Osaka Prefecture Osaka City Tsurumi-ku Release 1-10-25 East               Okuno Pharmaceutical Industry Co., Ltd. F term (reference) 4D050 AA08 AB18 BB03 BB06 BB07                 4K022 BA01 BA03 BA08 BA14 BA18                       DA01 DB01

Claims (5)

[Claims] 1. A method for preparing a plating bath, which comprises adding an oxide halide to a plating bath to oxidatively decompose an organic compound contained in the plating bath. 2. The oxidized halide is hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromic acid, bromic acid, bromic acid, perbromic acid, hypoiodic acid, iodic acid. , Iodic acid,
2. The method for adjusting a plating bath according to claim 1, which is at least one selected from the group consisting of periodic acid and salts thereof. 3. The method for preparing a plating bath according to claim 1, wherein the plating bath is an acidic electroplating bath or an acidic electroless plating bath. 4. The method for preparing a plating bath according to claim 3, wherein the plating bath is a copper sulfate plating bath and the component to be decomposed is a sulfur-containing organic compound. 5. Hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromic acid, bromic acid, bromic acid, perbromic acid, hypoiodic acid, iodic acid, iodic acid, and peroxyacid. An organic compound decomposing agent in a plating bath, which contains, as an active ingredient, at least one kind of oxyhalide selected from the group consisting of iodic acid and salts thereof.