TW201300581A - Electro copper plating additive and electro copper plating bath - Google Patents

Abstract

Provided is an electro copper plating additive which forms a uniform plating film from low current density parts to high current density parts, imparting a lustrous shine, and which is not depleted when the bath is not in use. Also provided is an electro copper plating bath containing the additive. The present invention involves adding an electric copper plating additive comprising a block polymer compound represented by general formula (1) below to an electro copper plating bath. (In the formula, R represents a straight-chain or branched-chain alkenyl group or alkyl group having 1 to 15 carbon atoms, m is an integer from 1 to 30, and n is an integer from 1 to 40.)

Description

Copper plating additive and copper plating bath

The present invention relates to an additive for copper plating and a copper plating bath, and more particularly to an additive for copper plating suitable as a brightener for a copper sulfate plating bath and a copper plating bath containing the additive.

The present application claims priority on the basis of Japanese Patent Application No. 2011-070667, filed on Jan. 28, 2011, the entire disclosure of which is hereby incorporated by reference.

Conventionally, a method of adding a gloss agent to a copper plating bath to impart a glossy copper plating film has been carried out. The brightening agent is, for example, an organic sulfur compound, an oxygen-containing polymer organic compound, and the like (for example, refer to Patent Document 1 or 2). As the organic sulfur compound, a disulfide-based compound such as NaO ₃ SC ₃ H ₆ S-SC ₃ H ₆ SO ₃ Na or the like is widely used, and an oxyalkylene polymer and poly are widely used as an oxygen-containing polymer organic compound. Ethylene glycol, polypropylene glycol, and the like.

Further, as the gloss agent other than the above compound, a polymer obtained by adding ethylene oxide to polypropylene glycol represented by the following general formula can be used. In the formula, EO represents an oxyethylene group, PO represents an oxypropylene group, and n = a + b.

H-(EO)a-(PO)m-(EO)b-H

However, the gloss agent used in the past has insufficient glossiness and throwing power in the low current density portion of the copper plating film to form a rough film. The reason can be considered as: for example, in the polymer represented by the above general formula The (PO)m of the hydrophobic group is sandwiched between (EO) n on both sides, and the effect as a hydrophobic group is weakened. As a result, when a compound composed of the polymer is used as a brightening agent for a copper plating bath, a disorder of current distribution occurs at a low current density portion or a high current density portion, and uniform electrodeposition is inhibited, resulting in a fine concave. Poor plating due to pits or whitening.

In addition, the gloss agent for copper plating is required to be easy to manage and is not consumed even when not in use.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-194608

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2008-297221

Accordingly, the present invention has been made in view of the above-described conventional circumstances, and an object of the invention is to provide a uniform plating film from a low current density portion to a high current density portion, thereby imparting good gloss, even when not in use. The copper plating additive and the copper plating bath containing the additive are also not consumed.

The inventors of the present invention have intensively studied to solve the above problems, and as a result, found that a block polymer combination by using an effect of improving a hydrophobic group has been found. As an additive, a uniform plating film can be formed from a low current density portion to a high current density portion to impart good gloss, and thus the present invention has been completed.

That is, the additive for copper plating of the present invention is composed of a block polymer compound represented by the following general formula (1).

(wherein R represents an alkyl or alkenyl group having 1 to 15 carbon atoms in a straight or branched chain, m is 1 to 30, and n is an integer of 1 to 40)

Further, the copper plating bath of the present invention contains an additive composed of the block polymer compound represented by the above general formula (1).

According to the present invention, a uniform plating film can be formed from the low current density portion to the high current density portion, and good gloss can be imparted, and even if it is not used, it is not consumed, and a favorable plating film can be stably formed.

Hereinafter, the additive for copper plating and the copper plating bath containing the additive of the present embodiment will be described in detail.

The additive for copper plating of the present embodiment is composed of a block polymer compound represented by the following general formula (1).

Here, in the general formula (1), R represents an alkyl group or an alkenyl group having 1 to 15 carbon atoms in a straight chain or a branched chain, m is 1 to 30, and n is an integer of 1 to 40.

Examples of R of an alkyl group or an alkenyl group having 1 to 15 carbon atoms in a straight chain or a branched chain include a methyl group, an ethyl group, a n-propyl group, an allyl group, a n-butyl group, a n-pentyl group, and a n-hexyl group. 1-methylhexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-decyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecane Base, n-pentadecyl and the like.

Further, m and n in the general formula (1) can be appropriately set in accordance with the type of the above R. Specifically, as the carbon number of R increases, the hydrophobicity increases, and by adjusting the molar ratio of m and n in accordance with the type of R, the plating bath can have appropriate solubility. Further, m and n are preferably set such that the molecular weight of the block polymer represented by the general formula (1) is 500 to 2,000.

As shown in the above general formula (1), the additive has a structure in which an end of the oxypropylene group side is covered with an alkyl group or an alkenyl group. Thus, by covering the terminal of the oxypropylene group with an alkyl group or an alkenyl group, the effect of the oxypropylene group as a hydrophobic group can be enhanced.

Further, in the above general formula (1), the order of the oxypropylene group (PO) and the oxyethylene group (EO) is constant, and is often A block polymer composed of a structure of R-O-(PO)m-(EO)n-H. Thereby, as described above, the oxypropylene group ((PO)m) which is covered with an alkyl group or an alkenyl group at the terminal can give [RO-(PO)m] in the above general formula (1). Part of the overall action is a hydrophobic group with high hydrophobicity.

The effect predicted from this content is as follows. Generally, since the hydrophobic group of the compound is pressed from the water to the interface, when the object to be plated is immersed in the aqueous solution, the plated surface of the object to be plated becomes an interface and has a high The hydrophobic additive is concentrated on the plated surface to enhance the effect of the additive. As a result, the effect of the additive can be exhibited from the low current density portion to the high current density portion, so that a uniform plating film can be formed and a good gloss can be imparted.

Further, by such a block polymer, it is possible to have a moderate solubility by the oxyethylene group at the other end, so that the polymer compound is well dissolved in the copper plating bath and stabilized in the plating bath. The ground is maintained, and when it is not used for electrolytic treatment, consumption over time can be suppressed.

The block polymer compound represented by the above general formula (1) can be produced, for example, by the following method. That is, propylene oxide can be first reacted and reacted with an alkanol or an enol having 1 to 15 carbon atoms in an inert gas atmosphere such as nitrogen. After completion of the addition reaction of propylene oxide, ethylene oxide is added to carry out an addition reaction of ethylene oxide.

In this manner, the block polymer compound is obtained by adding propylene oxide to an alkanol or an enol having 1 to 15 carbon atoms, and then adding an ethylene oxide to carry out an addition reaction, thereby synthesizing it. EO)n is a block formed by a certain structure of (PO)m covered with an alkyl group or an alkenyl group.

The reaction temperature in the method for producing the block polymer compound is not particularly limited, but is preferably 90 to 160 °C. By setting the reaction temperature to 90 ° C or higher, an appropriate reaction rate can be obtained, and an addition reaction of propylene oxide and ethylene oxide can be efficiently produced. Further, by setting the reaction temperature to 160 ° C or lower, the formation of by-products and the like can be suppressed, and the yield of the produced block polymer compound can be improved. When the addition reaction of the propylene oxide to the alkanol is carried out, it is preferred to carry out the addition reaction of the propylene oxide at the above-mentioned 90 to 160 ° C, and then to cool, and then in the same manner. The addition reaction of ethylene oxide is carried out under temperature conditions.

Further, the reaction time is not particularly limited and varies depending on the reaction temperature, and is preferably within 15 hours in each addition reaction of propylene oxide and ethylene oxide. By setting it to 15 hours or less, formation of a by-product etc. can be suppressed, and the yield of the block polymer compound produced can be improved.

Further, in the case of the addition reaction, it is preferred to carry out the reaction under pressure, and the pressure at the start of the addition reaction is preferably 2 to 5 kg/cm ² .

When the block polymer compound represented by the above general formula (1) is used as an additive for a copper plating bath, the concentration at this time is preferably 0.05 to 1.0 g/L. By setting the addition concentration to 0.05 g/L or more, a plating film having sufficient gloss can be formed. Further, by setting the addition concentration to 1.0 g/L or less, it is possible to prevent a reduction in the current density range which can be effectively used, and to form a favorable plating film uniformly from the low current density portion to the high current density portion.

Next, a copper plating bath to which an additive composed of the block polymer compound represented by the above general formula (1) is added, and copper plating using the same will be described. Bath plating treatment. The copper plating bath is not particularly limited, and is particularly preferably a copper sulfate plating bath. By adding the above-mentioned block polymer compound to the copper sulfate plating bath, it is possible to uniformly form a copper plating film having excellent gloss in a wide range of current densities, and it can be preferably used as a decorative plating. The plating bath used in the treatment.

Specifically, the composition of the copper sulfate plating bath can be, for example, an electroplating bath having a basic composition of copper sulfate (Cu ₂ SO ₄ .5H ₂ O) 50 to 250 g/L and concentrated sulfuric acid 50 to 250 g/L. In the copper sulfate plating bath, a trace amount (about 10 to 200 mg/L) of chloride ions is usually contained. Specifically, for example, a water-soluble chloride such as NaCl may be added to contain chloride ions.

In the above copper plating bath, gloss or smoothness can be further improved by further adding a known additive. Specifically, for example, an organic sulfur compound, an organic acid decylamine, an oxygen-containing polymer organic compound, or the like can be added.

The conditions of the plating treatment using the copper plating bath described above are such that the pH is 1 or less. Further, preferably, the plating temperature is in the range of 20 to 50 ° C, and the cathode current density is set to 0.1 to 8 A/dm ² . Further, a copper plate or an insoluble anode can be used for the anode. Further, in order to form a plating film having more uniform gloss, it is preferred to sufficiently perform stirring such as air stirring or cathode shaking.

In addition, the object to be plated which is subjected to the above-mentioned plating treatment is not particularly limited. For example, for the purpose of applying decorative plating to a material to be plated such as plastic, it is preferable to use copper to which the above additive is added. Electroplating bath. In addition, it is also possible to apply a plating treatment to a printed wiring board having through holes or electrical and electronic parts. Thus, copper plating with the above additives added Baths are widely available from decorative to functional purposes.

[Examples]

The following describes specific embodiments of the invention. However, the invention is not limited to any of the following embodiments.

In each of the examples described below, the block polymer (RO-(PO)m-(EO)nH) shown in Table 1 was synthesized, and a copper plating bath containing the block polymer compound as an additive was used. The plating treatment was performed, and the plating film after the formation of the precipitate was evaluated. Air is blown into the copper plating bath and thoroughly stirred, especially in the vicinity of the cathode to sufficiently bring the air into contact with the object to be plated.

<Example 1> (Synthesis of block polymer)

600 g (10 mol) of n-propanol and 5.6 g (0.1 mol) of potassium hydroxide were taken into a gas-tight reaction vessel under a nitrogen atmosphere at a pressure of 90-130 ° C and 2-5 kg/cm ² . 870 g (15 mol) of propylene oxide was subjected to an addition reaction. After completion of the addition reaction of propylene oxide, the reaction vessel was cooled, and then 660 g (15 mol) of ethylene oxide was added, and an addition reaction was carried out under the same conditions.

Then, 50 g of a synthetic adsorbent (Kyowaad 600, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the reaction vessel, and the mixture was stirred at 70 ° C for 30 minutes, followed by filtration to obtain polyoxyethylene (15) polyoxypropylene (15) propyl ether. 2070g.

(plating treatment and coating film evaluation)

10 mg/L of bis-(ω-sulfopropyl)-disulfide disodium salt, 50 mg/L of diazotized product of diethyl fragrant, and polyoxyethylene (15) polyoxypropylene synthesized above (15) Propyl ether 0.2g / L, added as an additive to copper sulfate plating consisting of copper sulfate (Cu ₂ SO ₄ .5H ₂ O) 200g / L, concentrated sulfuric acid 50g / L, NaCl 115mg / L A plating bath was obtained for the liquid, and the plating bath was used to carry out a plating treatment using a Hullcell tester at a total current of 2 A for 10 minutes. The plating treatment conditions were pH < 1, temperature 25 ° C, and cathode current density 0.15 to 4 A/dm ² .

As a result, a precipitate having a good gloss can be uniformly formed from the low current density portion to the high current density portion.

Further, even if the copper plate was placed in the above-described Hastelloy tester overnight, the plating treatment was performed in the same manner, and as in the initial plating treatment, precipitates having good gloss were uniformly formed. From the results, it was found that the additive can be stably maintained without being consumed in the plating bath even when it is not used.

<Example 2> (Synthesis of block polymer)

580 g (10 mol) of allyl alcohol (2-propen-1-ol) and 5.6 g (0.1 mol) of potassium hydroxide were taken into an airtight reaction vessel under a nitrogen atmosphere at 90-130 ° C, 2 870 g (15 mol) of propylene oxide was subjected to an addition reaction under a pressure of ~5 kg/cm ² . After completion of the addition reaction of propylene oxide, the reaction vessel was cooled, and then 660 g (15 mol) of ethylene oxide was added, and an addition reaction was carried out under the same conditions.

Then, 50 g of a synthetic adsorbent (Kyowaad 600, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the reaction vessel, and the mixture was stirred at 70 ° C for 30 minutes, followed by filtration to obtain polyoxyethylene (15) polyoxypropylene (15) allylate. Ether 2050 g.

(plating treatment and coating film evaluation)

In Example 2, except that 10 mg/L of bis-(ω-sulfopropyl)-disulfide disodium salt, 50 mg/L of diazotized treatment of diethyl russin, and polyoxygen after synthesis as described above were used. The electroplating treatment was carried out using a Hastelloy tester in the same manner as in Example 1 except that the ethylene (15) polyoxypropylene (15) allyl ether 0.2 g/L was used as an additive copper sulfate plating bath.

As a result, a precipitate having a good gloss can be uniformly formed from the low current density portion to the high current density portion. Further, even if the copper plate was placed in the above-described Hastelloy tester overnight, the plating treatment was performed in the same manner, and as in the initial plating treatment, precipitates having good gloss were uniformly formed.

<Example 3> (Synthesis of block polymer)

740 g (10 mol) of n-butanol and 5.6 g (0.1 mol) of potassium hydroxide were taken into a gas-tight reaction vessel under a nitrogen atmosphere at a pressure of 90 to 130 ° C and 2 to 5 kg/cm ² . 580 g (10 mol) of propylene oxide was subjected to an addition reaction. After completion of the addition reaction of propylene oxide, the reaction vessel was cooled, and then 660 g (15 mol) of ethylene oxide was added, and an addition reaction was carried out under the same conditions.

Then, 50 g of a synthetic adsorbent (Kyowaad 600, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the reaction vessel, and the mixture was stirred at 70 ° C for 30 minutes, followed by filtration to obtain polyoxyethylene (15) polyoxypropylene (10) dibutyl ether. 1920g.

(plating treatment and coating film evaluation)

In Example 3, except that 10 mg/L of bis-(ω-sulfopropyl)-disulfide disodium salt, 50 mg/L of diazotized treatment of diethyl russin, and polyoxygen after synthesis as described above were used. The electroplating treatment was carried out using a Hastelloy tester in the same manner as in Example 1 except that ethylene (15) polyoxypropylene (10) butyl ether 0.2 g/L was used as an additive copper sulfate plating bath.

As a result, a precipitate having a good gloss can be uniformly formed from the low current density portion to the high current density portion. Further, even if the copper plate was placed in the above-described Hastelloy tester overnight, the plating treatment was performed in the same manner, and as in the initial plating treatment, precipitates having good gloss were uniformly formed.

<Example 4> (Synthesis of block polymer)

1020 g (10 mol) of n-hexanol and 5.6 g (0.1 mol) of potassium hydroxide were weighed into an airtight reaction vessel, and under a nitrogen atmosphere, under a pressure of 90 to 130 ° C and 2 to 5 kg/cm ² . 290 g (5 mol) of propylene oxide was subjected to an addition reaction. After completion of the addition reaction of propylene oxide, the reaction vessel was cooled, and then 880 g (20 mol) of ethylene oxide was added, and an addition reaction was carried out under the same conditions.

Then, 50 g of a synthetic adsorbent (Kyowaad 600, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the reaction vessel, and the mixture was stirred at 70 ° C for 30 minutes, followed by filtration to obtain polyoxyethylene (20) polyoxypropylene (5) hexyl ether. 2130g.

(plating treatment and coating film evaluation)

In Example 4, except that 10 mg/L of bis-(ω-sulfopropyl)-disulfide disodium salt, 50 mg/L of diazotized product of diethyl russin, and polyoxygen after synthesis described above were used. The electroplating treatment was carried out using a Hastelloy tester in the same manner as in Example 1 except that ethylene (20) polyoxypropylene (5) hexyl ether 0.2 g/L was used as an additive copper sulfate plating bath.

As a result, a precipitate having a good gloss can be uniformly formed from the low current density portion to the high current density portion. Further, even if the copper plate was placed in the above-described Hastelloy tester overnight, the plating treatment was performed in the same manner, and as in the initial plating treatment, precipitates having good gloss were uniformly formed.

<Example 5> (Synthesis of block polymer)

1300 g (10 mol) of 2-ethylhexanol and 5.6 g (0.1 mol) of potassium hydroxide were taken into an airtight reaction vessel under a nitrogen atmosphere at 90-130 ° C and 2-5 kg/cm ² . 174 g (3 mol) of propylene oxide was subjected to an addition reaction under pressure. After completion of the addition reaction of propylene oxide, the reaction vessel was cooled, and then 1,100 g (25 mol) of ethylene oxide was added, and an addition reaction was carried out under the same conditions.

Then, 50 g of a synthetic adsorbent (Kyowaad 600, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the reaction vessel, and the mixture was stirred at 70 ° C for 30 minutes, followed by filtration to obtain polyoxyethylene (25) polyoxypropylene (3) 2 2,500 g of ethyl hexyl ether.

(plating treatment and coating film evaluation)

In Example 5, except that 10 mg/L of bis-(ω-sulfopropyl)-disulfide disodium salt, 50 mg/L of diazotized treatment of diethyl russin, and the above-mentioned polyoxygen after synthesis were used. A plating apparatus was carried out using a Hastelloy tester in the same manner as in Example 1 except that ethylene (25) polyoxypropylene (3) 2-ethylhexyl ether 0.2 g/L was used as an additive copper sulfate plating bath.

As a result, a precipitate having a good gloss can be uniformly formed from the low current density portion to the high current density portion. Further, even if the copper plate was placed in the above-described Hastelloy tester overnight, the plating treatment was performed in the same manner, and as in the initial plating treatment, precipitates having good gloss were uniformly formed.

<Example 6> (Synthesis of block polymer)

1860 g (10 mol) of 1-dodecanol and 5.6 g (0.1 mol) of potassium hydroxide were taken into a gas-tight reaction vessel under a nitrogen atmosphere at 90-130 ° C and 2-5 kg/cm ² . 116 g (2 mol) of propylene oxide was subjected to an addition reaction under pressure. After completion of the addition reaction of propylene oxide, the reaction vessel was cooled, and then 1320 g (30 mol) of ethylene oxide was added, and an addition reaction was carried out under the same conditions.

Then, 50 g of a synthetic adsorbent (Kyowaad 600, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the reaction vessel, and the mixture was stirred at 70 ° C for 30 minutes, followed by filtration to obtain polyoxyethylene (30) polyoxypropylene (2) twelve. Alkyl ether 3200g.

(plating treatment and coating film evaluation)

In Example 6, except that 10 mg/L of bis-(ω-sulfopropyl)-disulfide disodium salt, 50 mg/L of diazotized product of diethyl russin, and the above-mentioned polyoxygen after synthesis were used. The electroplating treatment was carried out using a Hastelloy tester in the same manner as in Example 1 except that the ethylene (30) polyoxypropylene (2) dodecane ether 0.2 g/L was used as an additive copper sulfate plating bath.

As a result, a precipitate having a good gloss can be uniformly formed from the low current density portion to the high current density portion. Further, even if the copper plate was placed in the above-described Hastelloy tester overnight, the plating treatment was performed in the same manner, and as in the initial plating treatment, precipitates having good gloss were uniformly formed.

<Comparative Example 1> (plating treatment and coating film evaluation)

In Comparative Example 1, except that bis-(ω-sulfopropyl)-disulfide disodium salt 10 mg/L, diammonium diazotized product 50 mg/L, and polyethylene glycol 0.2 g were used. The electroplating treatment was carried out using a Hastelloy tester in the same manner as in Example 1 except that the copper sulfate plating bath was used as an additive, and the deposited film after precipitation was evaluated. In Comparative Example 1 and Comparative Examples 2 and 3 below, air was also blown into the copper plating bath and sufficiently stirred.

As a result, although the precipitate has a good luster, fine pits or whitening occur, and uniform precipitates cannot be formed from the low current density portion to the high current density portion, and the plating film is poor in appearance.

<Comparative Example 2> (plating treatment and coating film evaluation)

In Comparative Example 2, except that 10 mg/L of bis-(ω-sulfopropyl)-disulfide disodium salt, 50 mg/L of diazotized product of diethyl russin, and 0.2 g/L of polypropylene glycol were used. The plating treatment was carried out using a Hastelloy tester in the same manner as in Example 1 except that the copper sulfate plating bath was used as an additive, and the deposited film after precipitation was evaluated.

As a result, although the precipitate has a good luster, fine pits or whitening occur, and uniform precipitates cannot be formed from the low current density portion to the high current density portion, and the plating film is poor in appearance.

<Comparative Example 3> (plating treatment and coating film evaluation)

In Comparative Example 3, except that 10 mg/L of bis-(ω-sulfopropyl)-disulfide disodium salt, 50 mg/L of diazotized product of diethyl russin, and ethylene oxide were added. Block polymer obtained from polypropylene glycol (H-(EO)a-(PO)m-(EO)bH, m=17, n=a+b=9) 0.2 g/L copper sulfate as an additive The electroplating treatment was carried out using a Hastelloy tester in the same manner as in Example 1 except for the electroplating bath, and the deposited film after precipitation was evaluated.

As a result, although the precipitate has a good luster, fine pits or whitening occur, and uniform precipitates cannot be formed from the low current density portion to the high current density portion, and the plating film is poor in appearance.

<Comparative Example 4> (plating treatment and coating film evaluation)

In Comparative Example 4, except that bis-(ω-sulfopropyl)-disulfide disodium salt 10 mg/L, diazo sulphate diazotization treatment 50 mg/L, and ethylene oxide were simultaneously used. The same as in Example 1, except that the propylene oxide was added to n-butanol and the random polymer was 0.2 g/L of the copper sulfate plating bath as an additive, and the plating treatment was performed using a Hastelloy tester and evaluated. The formed plating film was deposited.

As a result, the precipitate has a good luster, but the step plating film is changed in a stepwise manner, and the plating film is not deposited on the low current density portion, and the plating film is poor in appearance.

Claims (3)

An additive for copper plating, which is composed of a block polymer compound represented by the following general formula (1); (In the formula, R represents an alkyl group or an alkenyl group having 1 to 15 carbon atoms in a straight or branched chain, m is 1 to 30, and n is an integer of 1 to 40). The additive for copper plating according to claim 1, wherein the block polymer compound is added by reacting propylene oxide with an alkyl alcohol or an enol having 1 to 15 carbon atoms in an inert gas atmosphere. Ethylene oxide is obtained by addition reaction. A copper electroplating bath comprising the above-mentioned additive for copper electroplating according to item 1 of the patent application.