JP4632027B2 - Lead-free tin-silver alloy or tin-copper alloy electroplating bath - Google Patents

Description

  The present invention relates to tin-tin or tin-copper alloy electroplating baths that are lead-free (thus, tin-containing plating baths containing lead such as tin-silver-lead alloy baths are excluded). An object of the present invention is to suppress the excessive depletion of silver or copper in a plating bath and to stabilize the bath composition by effectively preventing substitution deposition of silver or copper on the surface of the alloy anode.

In recent years, there has been a concern about the influence of lead on the human body and the environment. Since pure tin plating may cause whisker, development of solder plating that does not contain lead is desired.
Tin-bismuth alloy, tin-silver alloy, tin-copper alloy, etc. have been studied as promising candidates for lead-free solder, but tin-bismuth alloy has a problem that cracks are likely to occur during machining. On the other hand, there are few such problems with tin-silver alloys and tin-copper alloys.

Patent documents 1-7 are mentioned as conventional technology of the electroplating bath of the above-mentioned tin-silver system alloy or tin-copper system alloy.
Patent Document 1 describes a tin alloy plating bath containing a tin-silver alloy and a tin-copper alloy that can contain various nonionic surfactants (see claim 1, paragraph 35), and Example 4 thereof. -6 contains a tin-silver alloy plating bath containing polyoxyethylene polyoxypropylene glycol and bisphenol A polyethoxylate, and Examples 9-10 contain dodecyl alcohol polyethoxylate and octylphenol polyethoxylate. A tin-copper alloy plating bath is specifically described.

  Patent Document 2 describes a tin alloy plating bath containing a tin-silver alloy and a tin-copper alloy containing various nonionic surfactants (see claim 1, paragraph 21). Is a tin-silver alloy plating bath containing laurylamine polyethoxylate. Examples 7, 14, and 16 include tin containing polyoxyethylene polyoxypropylene block polymer and α-naphthol polyethoxylate. -A copper alloy plating bath is specifically described.

  Patent Document 3 describes a silver alloy plating bath containing a silver-tin alloy that can contain various nonionic surfactants (see claim 1, claim 4, paragraphs 32-37), and examples thereof. 17 to 18 describe specific examples of silver-tin alloy plating baths containing bisphenol A polyethoxylate and nonylphenol polyethoxylate.

  Patent Document 4 describes a tin-copper alloy plating bath that can contain various nonionic surfactants (see claim 1, claim 4-5, paragraphs 19-22), Example 3 and the like. Example 7 describes a specific example of a tin-copper alloy plating bath containing tristyrenated phenol polyethoxylate (EO15), tristyrenated phenol polyethoxylate (EO15) polypropoxylate (PO3). .

  Patent Document 5 describes a tin-copper alloy plating bath that can contain various nonionic surfactants (see claim 1, paragraphs 51 to 54). A tin-copper alloy plating bath containing styrenated phenol polyethoxylate (EO15) polypropoxylate (PO3) is shown in Examples 4B-7B, a tin-copper-silver alloy plating containing α-naphthol polyethoxylate. The bath is specifically described.

  Patent Document 6 describes a tin-copper alloy plating bath containing various nonionic surfactants (see claims 1 and 2, paragraphs 23 to 26), and Examples 10 to 14 thereof include: A tin-copper-iron alloy plating bath containing tristyrenated phenol polyethoxylate (EO15) polypropoxylate (PO3) is shown in Examples 16-19 in tin-copper-containing β-naphthol polyethoxylate. Specific examples of nickel alloy plating baths are described in Examples 20 to 24, which are tin-copper-cobalt alloy plating baths containing β-naphthol polyethoxylate.

  Patent Document 7 describes a tin-copper alloy plating bath that can contain various nonionic surfactants (see claims 1 and 2, paragraphs 19 to 22), and Examples 1 to 3 thereof. A tin-copper alloy plating bath containing tristyrenated phenol polyethoxylate (EO15) polypropoxylate (PO3) is described in Example 14 as tristyrenated phenol polyethoxylate (EO15) polypropoxylate (PO3). In Examples 17-18, a tin-copper-nickel alloy plating bath containing tristyrenated phenol polyethoxylate (EO15) polypropoxylate (PO3), Example 21 specifically describes a tin-copper-antimony alloy plating bath containing tristyrenated phenol polyethoxylate (EO15) polypropoxylate (PO3).

Japanese Patent Laid-Open No. 10-25595 JP 2000-26991 A JP 2000-192279 A JP 2001-49486 A JP 2001-164396 A JP 2001-172791 A JP 2001-262391 A

In actual tin-silver alloy or tin-copper alloy electroplating, tin or tin alloy is used for the anode from the viewpoint of productivity reduction, but the electrode potential of silver or copper is precious against tin. Therefore, when the anode is immersed in the electroless plating at the time of electroplating, there are problems that tin is dissolved from the anode and silver or copper is substituted and deposited on the anode surface. In particular, silver is unstable and easily precipitated in a bath because the electrode potential is greatly inclined.
When the consumption of silver or copper by this substitution proceeds, the concentration of silver or copper in the plating bath decreases, the plating bath composition changes, the alloy composition of the electrodeposits changes, and the cost increases. Furthermore, when silver or copper is substituted and deposited on an object to be plated, it also adversely affects the solder wettability and bonding strength of the electrodeposited film.
A tin alloy plating bath containing the tin-silver alloy and tin-copper alloy of Patent Literatures 1 and 2, a silver alloy plating bath containing the silver-tin alloy of Patent Literature 3, and tin-copper alloy platings of Examples 4 to 7 The bath is not intended to prevent substitution deposition of silver or copper on the anode surface during electroplating, and therefore the prevention function cannot be expected or is insufficient.

  The present invention is a lead-free tin-silver alloy or tin-copper alloy electroplating bath that effectively prevents substitutional deposition of silver or copper on the surface of the tin or tin alloy anode during the plating process, thereby improving the bath composition. Stabilization is a technical issue.

For the various nonionic surfactants listed in Patent Documents 1 to 7 above, the present inventors have included the inclusion of these surfactants in the substitution deposition of silver or copper on the surface of the tin or tin alloy anode. As a result of diligent research on the effects of these substances, it has been found that, among the same nonionic surfactants, those having a specific chemical structural type having a given HLB have a clear difference in the anti-substitution function compared to others. I found it.
That is, the nonionic surfactant having a specific chemical structure selected from di- or tristyrenated phenol polyalkoxylate having a predetermined HLB and di- or tristyrenated cresol polyalkoxylate has a unique effect of preventing this substitutional precipitation. In particular, it has a significant advantage over nonionic surfactants other than these, and the plating bath composition containing a specific chemical structural species stabilizes the plating bath composition. As a result, the present invention was completed.

That is, the present invention 1 is at least one acid selected from a soluble stannous salt, a soluble silver salt, an inorganic acid composed of hydrochloric acid, sulfuric acid, and borohydrofluoric acid, an organic sulfonic acid, and an organic acid composed of a carboxylic acid. In a lead-free tin-silver alloy electroplating bath containing
Distyrenated phenol polyalkoxylate with HLB 7.3-15.2, Tristyrenated phenol polyalkoxylate with HLB 7.0-10.4, Distyrenated cresol polyalkoxy with HLB 8.2-15.0 Addition of at least one nonionic surfactant comprising a tristyrenated cresol polyalkoxylate having a rate, HLB of 7.7 to 13.9, and substitution deposition of silver on the anode surface made of tin or tin alloy This is a lead-free tin-silver alloy electroplating bath characterized by

  Invention 2 is a lead-free lead according to Invention 1, wherein the tin-silver alloy is a tin-silver-copper alloy, and the electroplating bath contains a soluble copper salt as a copper supply source. It is a tin-silver alloy electroplating bath.

The present invention 3 includes a soluble stannous salt, a soluble copper salt, and at least one acid selected from an inorganic acid composed of hydrochloric acid, sulfuric acid, borohydrofluoric acid, an organic sulfonic acid, and an organic acid composed of a carboxylic acid. In the contained lead-free tin-copper alloy electroplating bath,
Distyrenated phenol polyalkoxylate with HLB 7.3-15.2, Tristyrenated phenol polyalkoxylate with HLB 7.0-10.4, Distyrenated cresol polyalkoxy with HLB 8.2-15.0 Addition of at least one nonionic surfactant comprising a tristyrenated cresol polyalkoxylate having a rate, HLB of 7.7 to 13.9, and substitution deposition of copper on the anode surface made of tin or tin alloy This is a lead-free tin-copper alloy electroplating bath characterized by

  Invention 4 is a multi-component alloy according to any one of Inventions 1 to 3, wherein the tin-silver alloy or the tin-copper alloy further contains another metal, and the solubility of the other metal in the electroplating bath A lead-free tin-silver alloy or tin-, which contains a salt and the other metal is at least one selected from the group consisting of zinc, indium, antimony, iron, cobalt, nickel, iridium This is a copper alloy electroplating bath.

  The present invention 5 further comprises at least one of a surfactant, a complexing agent, an antioxidant, a smoothing agent, a semi-brightening agent, a brightening agent, a conductive salt, and a pH adjusting agent in any one of the present inventions 1 to 4. A lead-free tin-silver alloy or tin-copper alloy electroplating bath characterized by comprising

The present invention 6 immerses an anode and a cathode in a lead-free tin alloy plating bath, and performs electroplating using tin or tin alloy as an anode and an object to be plated as a cathode.
By using the tin alloy electroplating bath according to any one of the present inventions 1 to 5, it is possible to prevent substitution deposition of silver or copper on the surface of the anode. Or it is a tin-copper alloy electroplating method.

  The present invention 7 is an electronic component in which a lead-free tin-silver alloy or tin-copper alloy film is formed on the substrate using the tin alloy electroplating bath according to any one of the present inventions 1 to 5. .

(1) Although the above Patent Documents 1 to 7 list various nonionic surfactants, as shown in the test examples described later, ordinary nonionic surfactants that are not appropriate selected species, or However, even if a surfactant other than nonionic is contained in the plating bath, substitution deposition of silver or copper on the surface of tin or tin alloy anode cannot be effectively prevented.
Incidentally, the tristyrenated phenol polyethoxylate (EO15), tristyrenated phenol polyethoxylate (EO15) polypropoxylate (PO3) described in Patent Documents 4 to 7 has an HLB of 12.4 or 10.6. And deviates from the appropriate range of the HLB of the present invention.
On the other hand, in the present invention, since a nonionic surfactant of a specific chemical structural type having a predetermined HLB is added to a tin-silver alloy or tin-copper alloy plating bath, an anode made of tin or tin alloy is used. Substitutional precipitation of silver or copper on the surface can be effectively prevented (in particular, it is possible to smoothly prevent silver precipitation in which the electrode potential is greatly inclined). For this reason, excessive consumption of silver or copper in the plating bath can be eliminated, fluctuations in the plating bath composition can be suppressed and stabilized, and in electroplating, it has excellent denseness, smoothness, etc. An electrodeposited film of tin-silver alloy or tin-copper alloy can be obtained.

  (2) Since substitutional deposition of silver or copper on the anode surface can be effectively prevented, there is no need to clean the anode each time the plating operation is performed, and the plating operation can be simplified.

The present invention is first a lead-free tin-silver alloy electroplating bath containing a nonionic surfactant of a specific chemical structural species having a predetermined HLB (see the present invention 1-2), and second And a lead-free tin-copper alloy electroplating bath containing the nonionic surfactant (see the present invention 3). Third, by using these electroplating baths, silver is formed on the anode surface. Or a lead-free tin-silver alloy or tin-copper alloy electroplating method that prevents copper from being deposited by substitution (see the present invention 6), and fourth, tin is formed on the substrate surface by these plating baths. -An electronic component having a silver alloy or tin-copper alloy film formed thereon (see the present invention 7).
In the lead-free tin-silver alloy or tin-copper alloy electroplating bath or electroplating method of the present invention, from the viewpoint of productivity, the anode is not an insoluble material such as platinum, but tin or tin. An alloy is used as a material (therefore, prevention of substitutional precipitation of silver or copper becomes a problem).

The tin-silver alloy that is the subject of the present invention 1 is not limited to a binary alloy of tin-silver alloy, but as shown in the present invention 2 and the present invention 4, a tin-silver-copper alloy, tin-silver-zinc Alloy, tin-silver-indium alloy, tin-silver-antimony alloy, tin-silver-iron alloy, tin-silver-cobalt alloy, tin-silver-nickel alloy, tin-silver-iridium alloy ternary alloy, or , Other multi-element alloys containing tin and silver, but lead-free alloys such as tin-silver-lead alloys are excluded because they are lead-free.
In the present invention, for convenience, the tin-silver-copper alloy belongs to a tin-silver alloy, not a tin-copper alloy.
In the plating bath, a metal source such as tin or silver is contained in any form depending on the type of the bath as a metal compound that dissolves in acidic, neutral or alkaline water, and generally in the form of a soluble salt of the metal. Take.
Therefore, the basic composition of a tin-silver alloy electroplating bath (binary alloy bath) will be described. It consists of a soluble stannous salt, a soluble silver salt, and a base acid.
Examples of the soluble stannous salt include stannous salts of organic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, 2-propanolsulfonic acid, p-phenolsulfonic acid, stannous borofluoride, sulfosuccinic acid Examples include stannous, stannous sulfate, stannous oxide, and stannous chloride.
Examples of the soluble silver salt include silver sulfate, silver sulfite, silver carbonate, silver nitrate, silver oxide, silver sulfosuccinate, silver salts of the above organic sulfonic acids, silver citrate, silver tartrate, silver gluconate, silver oxalate, and the like. It is done.

Further, in the case of a ternary alloy electroplating bath such as tin-silver-zinc alloy or tin-silver-indium alloy, or a multi-component alloy bath higher than that, various soluble materials such as zinc, indium, antimony, iron, nickel, etc. Further salt is contained.
Examples of the soluble salt of indium include indium sulfamate, indium sulfate, indium borofluoride, indium oxide, indium methanesulfonate, and indium 2-hydroxypropanesulfonate.
Examples of the soluble salt of zinc include zinc sulfate, zinc nitrate, zinc chloride, zinc pyrophosphate, zinc cyanide, zinc methanesulfonate, zinc 2-hydroxyethanesulfonate, and zinc 2-hydroxypropanesulfonate.
Examples of the soluble salt of antimony include antimony borofluoride, antimony chloride, antimony potassium tartrate, potassium pyroantimonate, antimony tartrate, antimony methanesulfonate, and antimony 2-hydroxypropanesulfonate.
Examples of the soluble salt of iron include iron sulfate, iron chloride, iron acetate, iron thiocyanate, iron methanesulfonate, and iron 2-hydroxypropanesulfonate.
Examples of the soluble salt of cobalt include cobalt sulfate, cobalt chloride, cobalt acetate, cobalt borofluoride, cobalt methanesulfonate, and cobalt 2-hydroxypropanesulfonate.
Examples of the soluble salt of nickel include nickel sulfate, nickel formate, nickel chloride, nickel sulfamate, nickel borofluoride, nickel acetate, nickel methanesulfonate, nickel 2-hydroxypropanesulfonate.
Similarly, the soluble salt of the specific metal serving as the other alloy component includes an oxide, a halide, a salt of an inorganic acid or an organic acid (particularly, an organic sulfonate), and the like.

On the other hand, the tin-copper alloy that is the subject of the present invention 3 is not limited to a binary alloy of tin-copper alloy, but as shown in the present invention 4, a tin-copper-zinc alloy, a tin-copper-indium alloy, Tin-copper-antimony alloy, tin-copper-iron alloy, tin-copper-cobalt alloy, tin-copper-nickel alloy, tin-copper-iridium alloy ternary alloy (tin-copper-silver alloy is as described above) Or other multi-component alloys containing tin and copper, but lead-free alloys such as tin-copper-lead alloys are excluded. Is done.
In the tin-copper alloy plating bath, similarly to the above tin-silver alloy bath, metal sources such as tin and copper are metal compounds that dissolve in acidic, neutral or alkaline water, depending on the type of bath. It is contained in any form and generally takes the form of a soluble salt of a metal.
Therefore, the basic composition of a tin-copper alloy electroplating bath (binary alloy bath) is composed of a soluble stannous salt, a soluble copper salt, and a base acid, like the tin-silver alloy bath.
Examples of the soluble copper salt include copper salts of the organic sulfonic acid, copper sulfate, copper chloride, copper oxide, copper carbonate, copper acetate, copper pyrophosphate, copper oxalate and the like.
In addition, in the case of a ternary alloy electroplating bath such as tin-copper-zinc alloy or a multi-component alloy bath higher than that, each soluble salt such as zinc, indium, antimony, iron, nickel and the like should further be contained. become. This is the same as the tin-silver ternary alloy or multi-component alloy plating bath.

Each of the above-mentioned soluble metal salts can be used alone or in combination, and the total concentration of the soluble salt in the bath relative to the plating bath is 0.05 to 350 g / L, preferably 10 to 200 g / L in terms of metal salt. The mixing ratio of tin and other metals is appropriately determined according to the desired composition ratio of the tin alloy plating film.
Specifically, the content of the soluble stannous salt is suitably 1 to 300 g / L, preferably 5 to 190 g / L.
The content of the soluble silver salt is suitably 0.01 to 10 g / L, preferably 0.05 to 5 g / L.
The content of the soluble copper salt is suitably 0.01 to 30 g / L, preferably 0.05 to 5 g / L.

  Examples of the base acid include organic acids such as organic sulfonic acid and aliphatic carboxylic acid, inorganic acids such as borofluoric acid, silicofluoric acid, sulfamic acid, hydrochloric acid, sulfuric acid, and perchloric acid, and salts thereof. Can also be used. These acids can be used singly or in combination, and the acid content is 5 to 400 g / L, preferably 20 to 300 g / L.

Among the above base acids, organic sulfonic acids are preferable from the viewpoint of solubility of tin and ease of wastewater treatment.
Examples of the organic sulfonic acid include alkane sulfonic acid, alkanol sulfonic acid, and aromatic sulfonic acid, and the alkane sulfonic acid is represented by a chemical formula C _n H _{2n + 1} SO ₃ H (for example, n = 1 to 11). Specifically, methanesulfonic acid, ethanesulfonic acid, 1-propanesulfonic acid, 2-propanesulfonic acid, 1-butanesulfonic acid, 2-butanesulfonic acid, pentanesulfonic acid, hexanesulfonic acid, Examples include decane sulfonic acid and dodecane sulfonic acid.

Examples of the alkanol sulfonic acid include chemical formula C _m H _{2m + 1} —CH (OH) —C _p H _2p —SO ₃ H (for example, m = 0 to 6, p = 1 to 5).
In particular, 2-hydroxyethane-1-sulfonic acid (isethionic acid), 2-hydroxypropane-1-sulfonic acid (2-propanolsulfonic acid), 2-hydroxybutane-1 -In addition to sulfonic acid, 2-hydroxypentane-1-sulfonic acid, etc., 1-hydroxypropane-2-sulfonic acid, 3-hydroxypropane-1-sulfonic acid, 4-hydroxybutane-1-sulfonic acid, 2-hydroxy Examples include hexane-1-sulfonic acid.

The aromatic sulfonic acid is basically benzene sulfonic acid, alkyl benzene sulfonic acid, phenol sulfonic acid, naphthalene sulfonic acid, alkyl naphthalene sulfonic acid, naphthol sulfonic acid, etc., specifically, 1-naphthalene sulfonic acid, 2 -Naphthalenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, p-phenolsulfonic acid, cresolsulfonic acid, sulfosalicylic acid, nitrobenzenesulfonic acid, sulfobenzoic acid, diphenylamine-4-sulfonic acid and the like.
Among the organic sulfonic acids, methanesulfonic acid, ethanesulfonic acid, 2-propanolsulfonic acid, 2-hydroxyethanesulfonic acid, phenolsulfonic acid, cresolsulfonic acid and the like are preferable.

As the aliphatic carboxylic acids can be used carboxylic acid C ₁ -C _6, specifically, acetic acid, propionic acid, acetic acid, citric acid, tartaric acid, gluconic acid, sulfosuccinic acid, such as trifluoroacetic acid.

The tin-silver alloy or tin-copper alloy electroplating bath of the present invention effectively prevents substitution deposition of silver or copper on the surface of the tin or tin alloy anode, and has an excellent appearance by stabilizing the plating bath composition. From the viewpoint of forming a plating film, it is necessary to add a nonionic surfactant of a specific chemical structural species having a predetermined HLB.
Nonionic surfactants of specific chemical structural species having a predetermined HLB are as follows (a) to (d).
(a) a distyrenated phenol polyalkoxylate having an HLB of 7.3 to 15.2 (preferably 8.4 to 14.5)
(b) Tristyrenated phenol polyalkoxylate having an HLB of 7.0 to 10.4 (preferably 7.9 to 9.9)
(c) a distyrenated cresol polyalkoxylate having an HLB of 8.2 to 15.0 (preferably 9.9 to 14.3)
(d) Tristyrenated cresol polyalkoxylate having an HLB of 7.7 to 13.9 (preferably 9.1 to 13.1) The nonionic surfactants (a) to (d) are all alkylene oxide adducts. As the alkylene oxide to be added, C _{2 to} C ₄ alkylene oxide is suitable, and ethylene oxide (EO) and / or propylene oxide (PO) is preferable.

Generally, as the number of EO added increases, hydrophilicity increases and HLB increases, and as the number of PO added increases, lipophilicity increases and HLB decreases. Further, the HLB of polyoxyethylene alkyl ether can be usually expressed by HLB = E / 5 (E: weight fraction (%) of ethylene oxide). Therefore, in the nonionic surfactants (a) to (d), from the viewpoint of effectively ensuring an emulsifying action in an aqueous system, the addition number of EO and PO, or a styrene group, based on the above formula By adjusting the added number, the HLB of the predetermined area can be adjusted.
In addition, in the case of a nonionic surfactant, once the type is specified, it is not so difficult to obtain an equivalent product whose HLB is specified within a desired range from the manufacturer.
Therefore, specific examples for each of the above specific chemical structural species are listed individually. For example, distyrenated phenol polyethoxylate (EO 9 mol) belongs to a specific region of HLB = 7.3 to 15.2, and tristyrenated phenol. Polyethoxylate (EO7 mol) belongs to a specific region of HLB = 7.0 to 10.4, and distyrenated cresol polypropoxylate (PO2 mol) / polyethoxylate (EO15 mol) has HLB = 8.2-15. It belongs to a specific region of 0, and tristyrenated cresol polyethoxylate (EO 10 mol) belongs to a specific region of HLB = 7.7 to 13.9.
The nonionic surfactants (a) to (d) can be used singly or in combination, and the content thereof is 0.005 to 5 mol / l with respect to 1 mol / L of silver in a tin-silver alloy electroplating bath. L is appropriate, preferably 0.01 to 2 mol / L, more preferably 0.05 to 1 mol / L. Further, the content (mol / L) of the nonionic surfactant relative to 1 mol / L of copper in the tin-copper alloy electroplating bath is the same as that of the tin-silver alloy bath.

In the present invention, it is a necessary condition that the lead-free tin-silver alloy or tin-copper alloy electroplating bath contains the nonionic surfactant of the above-mentioned specific chemical structure type, but other types of nonionic interface Surfactants such as amphoterics, anions and cations other than activators and nonionics may coexist.
These surfactants promote the solubilization of nonionic surfactants of the above-mentioned specific chemical structural species that have low water solubility, and the appearance, denseness, smoothness, adhesion, and uniform electrodeposition of the plating film. It is added to improve the properties.
As the surfactant, various surfactants such as nonionic, anionic, cationic, and amphoteric can be used singly or in combination, and the addition amount is preferably about 0.01 to 100 g / L with respect to the plating bath. About 0.1-50 g / L is preferable.

The nonionic surfactant, C ₁ -C ₂₀ alkanols, phenol, naphthol, monostyrenated phenol, monostyrenated cresol, cumylphenol, bisphenol, C ₁ -C ₂₅ alkyl phenol, C ₁ -C ₂₅ alkyl naphthol C ₁ -C ₂₅ alkoxylated phosphoric acid (salt), sorbitan ester, polyalkylene glycol, alkylene diamine, C ₁ -C ₂₂ aliphatic amide, sulfonamide, phosphoric acid, polyhydric alcohol, glucoside, ethylene oxide (EO) And an alkylene oxide adduct obtained by addition condensation of 2 to 300 mol of at least one alkylene oxide selected from propylene oxide (PO).
Therefore, any of the above alkanols, phenols, naphthols and other EO single adducts, PO single adducts, or EO and PO coexisting adducts may be used. Specifically, α-naphthol or β-naphthol ethylene oxide adduct (that is, α-naphthol polyethoxylate or the like) is preferable.

Examples of the C ₁ -C ₂₀ alkanol for addition condensation of the alkylene oxide include octanol, decanol, dodecanol, tetradecanol, hexadecanol, octadecanol, eicosanol, hexadecanol, cis-9-octadecenol, docosanol and the like. It is done.

  Bisphenol A, bisphenol B, bisphenol F, etc. are mentioned as bisphenols which carry out addition condensation of the said alkylene oxide.

Examples of the C ₁ -C ₂₅ alkylphenol for addition condensation of the alkylene oxide include mono, di, or trialkyl substituted phenols such as p-butylphenol, p-isooctylphenol, p-nonylphenol, p-hexylphenol, 2,4- Examples include dibutylphenol, 2,4,6-tributylphenol, p-dodecylphenol, and p-octadecylphenol.

Examples of the alkyl group of the C ₁ -C ₂₅ alkyl naphthol for addition condensation of the alkylene oxide include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, octadecyl, etc., and can be located at any position of the naphthalene nucleus. Good.

The C ₁ -C ₂₅ alkoxylated phosphoric acid (salt) for addition condensation of the alkylene oxide is represented by the following general formula (a).
Ra · Rb · (MO) P = O (a)
(In the formula (a), Ra and Rb are the same or different C ₁ -C ₂₅ alkyl, provided that one is better even H .M represents H or an alkali metal.)

  As the sorbitan ester for addition condensation of the alkylene oxide, mono-, di- or triesterized 1,4-, 1,5- or 3,6-sorbitan, specifically, sorbitan monolaurate, sorbitan monopalmitate Sorbitan distearate, sorbitan dioleate, sorbitan mixed fatty acid ester and the like.

Examples of the C ₁ -C ₂₂ aliphatic amide for addition condensation of alkylene oxide include amides such as propionic acid, butanoic acid, octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid and docosanoic acid.

Examples of the cationic surfactant include a quaternary ammonium salt represented by the following general formula (b) and a pyridinium salt represented by the following general formula (c).
_{(R 1 · R 2 · R} 3 · R 4 N) + · X - ... (b)
(In the formula (b), X is halogen, hydroxy, C ₁ -C ₅ alkanesulfonic acid or sulfuric acid, R ₁ , R ₂ and R ₃ are the same or different C ₁ -C ₂₀ alkyl, and R ₄ is C ₁ -C _{10 represents} alkyl or benzyl.)
R _6- (C ₆ H ₄ N-R ₅ ) ⁺ · X ⁻ (c)
(Wherein (in c), X is a halogen, hydroxy, C ₁ -C ₅ alkane sulfonic acid or sulfuric acid, R ₅ is C ₁ -C ₂₀ alkyl, R ₆ is H or C ₁ -C ₁₀ alkyl.)

  Examples of the cationic surfactant in the form of the salt include dodecyltrimethylammonium salt, octadecyltrimethylammonium salt, dodecyldimethylethylammonium salt, octadecyldimethylethylammonium salt, dimethylbenzyldodecylammonium salt, hexadecyldimethylbenzylammonium salt, Examples include octadecyldimethylbenzylammonium salt, trimethylbenzylammonium salt, triethylbenzylammonium salt, hexadecylpyridinium salt, dodecylpyridinium salt, octadecylpyridinium salt, dodecylamine acetate, and octadecylamine acetate.

Examples of the anionic surfactant include alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, alkyl benzene sulfonates, (mono, di, tri) alkyl naphthalene sulfonates, and the like. It is done.
Examples of the alkyl sulfate include sodium dodecyl sulfate and sodium cis-9-octadecenyl sulfate.
Examples of the polyoxyethylene alkyl ether sulfate include sodium polyoxyethylene (EO12) nonyl ether sulfate and sodium polyoxyethylene (EO15) dodecyl ether sulfate.
Examples of the polyoxyethylene alkylphenyl ether sulfate include polyoxyethylene (EO15) nonylphenyl ether sulfate.
Examples of the alkylbenzene sulfonate include sodium dodecylbenzenesulfonate.
Examples of the (mono, di, tri) alkyl naphthalene sulfonate include sodium dibutyl naphthalene sulfonate.

  Examples of the amphoteric surfactant include carboxybetaine, imidazoline betaine, sulfobetaine, and aminocarboxylic acids. Further, sulfated or sulfonated adducts of condensation products of ethylene oxide and / or propylene oxide with alkylamines or diamines can also be used.

  Representative carboxybetaines or imidazoline betaines include dodecyldimethylaminoacetic acid betaine, tetradecyldimethylaminoacetic acid betaine, octadecyldimethylaminoacetic acid betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, 2-undecyl-1-carboxymethyl-1 -Hydroxyethyl imidazolinium betaine, 2-octyl-1-carboxymethyl-1-carboxyethyl imidazolinium betaine, etc. are mentioned. Examples of sulfated or sulfonated adducts include sulfated adducts of ethoxylated alkylamines, sodium sulfonated dodecyl acid derivatives, and the like.

  Examples of the sulfobetaines include coconut oil fatty acid amidopropyldimethylammonium-2-hydroxypropanesulfonic acid, N-cocoylmethyl taurine sodium, and N-hexadecanoylmethyl taurine sodium.

  Examples of the aminocarboxylic acids include dioctylaminoethylglycine, N-dodecylaminopropionic acid, and octyldi (aminoethyl) glycine sodium salt.

Moreover, as shown in the present invention 5, the tin-silver alloy or tin-copper alloy electroplating bath of the present invention may further include a complexing agent, an antioxidant, a smoothing agent, and a semi-brighting agent as necessary. Various additives such as a brightener, a conductive salt, a pH adjuster, a buffer, a preservative, and an antifoaming agent can be contained.
The complexing agent is added mainly for the purpose of improving the stability of the bath by acting on the silver salt or copper salt.
Examples of the complexing agent include gluconic acid, citric acid, glucoheptonic acid, gluconolactone, glucoheptlactone, oxalic acid, malonic acid, succinic acid, glycolic acid, malic acid, tartaric acid, diglycolic acid, lactic acid, and these Salts of ethylenediamine, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), iminodipropionic acid (IDP), and salts thereof, sulfur complexing agents and the like.
This sulfur complexing agent is a compound containing a sulfur atom having a loan pair in the molecule. Specific examples thereof include thiourea, dimethylthiourea, trimethylthiourea, diethylthiourea, allylthiourea, acetylthiourea, thiol. thioamides such as thiourea derivatives such as semicarbazide, thioglycolic (HSCH ₂ CH ₂ OH), thioglycolic acid (HSCH ₂ COOH), mercaptopropionic acid _{(CH 3 CH (SH) COOH} ), such as mercaptosuccinic acid mercaptans, thiodiglycol _{(HOCH 2 CH 2 -S-CH} 2 CH 2 OH), H- (OCH 2 CH 2) 12 -S- (CH 2 CH 2 O) 12 -H, thio diglycolic acid (HOOCCH ₂ -S-CH ₂ COOH), dithio dianiline, dipyridyl disulfide, 3,6-dithio-1,8 Kutanjioru, 4,7 sulfides such as dithio-1,10-decanediol, or include sulfites and the like.

The above-mentioned antioxidant is for the purpose of preventing the oxidation of Sn ^{2+ in} the bath. Ascorbic acid or a salt thereof, hydroquinone, catechol, resorcin, phloroglucin, cresolsulfonic acid or a salt thereof, phenolsulfonic acid or a salt thereof, catechol Examples include sulfonic acid or a salt thereof, hydroquinone sulfonic acid or a salt thereof, resorcinsulfonic acid or a salt thereof, hydroxynaphthalene sulfonic acid or a salt thereof, and hydrazine.

Examples of the smoothing agent include β-naphthol, β-naphthol-6-sulfonic acid, β-naphthalenesulfonic acid, m-chlorobenzaldehyde, p-nitrobenzaldehyde, p-hydroxybenzaldehyde, (o-, p-) methoxybenzaldehyde, Vanillin, (2,4-, 2,6-) dichlorobenzaldehyde, (o-, p-) chlorobenzaldehyde, 1-naphthaldehyde, 2-naphthaldehyde, 2 (4) -hydroxy-1-naphthaldehyde, 2 ( 4) -Chloro-1-naphthaldehyde, 2 (3) -thiophenecarboxaldehyde, 2 (3) -furaldehyde, 3-indolecarboxaldehyde, salicylaldehyde, o-phthalaldehyde, formaldehyde, acetaldehyde, paraaldehyde, butyraldehyde , Isobutyraldehyde, propi Onaldehyde, n-valeraldehyde, acrolein, crotonaldehyde, glyoxal, aldol, succindialdehyde, capronaldehyde, isovaleraldehyde, allylaldehyde, glutaraldehyde, 1-benzylidene-7-heptanal, 2,4-hexadienal, Cinnamaldehyde, benzylcrotonaldehyde, amine-aldehyde condensate, mesityl oxide, isophorone, diacetyl, hexanedione-3,4, acetylacetone, 3-chlorobenzylideneacetone, sub.pyridylideneacetone, sub.furfuridineacetone, sub. Tenylideneacetone, 4- (1-naphthyl) -3-buten-2-one, 4- (2-furyl) -3-buten-2-one, 4- (2-thiophenyl) -3-butene-2- On, Kurkumi Benzylideneacetylacetone, benzalacetone, acetophenone, (2,4-3,4-) dichloroacetophenone, benzylideneacetophenone, 2-cinnamylthiophene, 2- (ω-benzoyl) vinylfuran, vinylphenylketone, acrylic acid, Methacrylic acid, ethacrylic acid, ethyl acrylate, methyl methacrylate, butyl methacrylate, crotonic acid, propylene-1,3-dicarboxylic acid, cinnamic acid, (o-, m-, p-) toluidine, (o-, p-) aminoaniline, aniline, (o-, p-) chloroaniline, (2,5-3,4-) chloromethylaniline, N-monomethylaniline, 4,4'-diaminodiphenylmethane, N-phenyl- (α-, β-) naphthylamine, methylbenztriazole, 1,2,3-triazine, 1,2,4-triazine 1,3,5-triazine, 1,2,3-benztriazine, imidazole, 2-vinylpyridine, indole, quinoline, reaction product of monoethanolamine and o-vanillin, polyvinyl alcohol, catechol, hydroquinone, resorcin, polyethylene Examples include imine, disodium ethylenediaminetetraacetate, and polyvinylpyrrolidone.
Gelatin, polypeptone, N- (3-hydroxybutylidene) -p-sulfanilic acid, N-butylidenesulfanilic acid, N-cinnamoylidenesulfanilic acid, 2,4-diamino-6- (2'-methylimidazolyl) (1 ′)) ethyl-1,3,5-triazine, 2,4-diamino-6- (2′-ethyl-4-methylimidazolyl (1 ′)) ethyl-1,3,5-triazine, 2, 4-Diamino-6- (2'-undecylimidazolyl (1 ')) ethyl-1,3,5-triazine, phenyl salicylate or benzothiazoles are also effective as a smoothing agent.
Examples of the benzothiazoles include benzothiazole, 2-methylbenzothiazole, 2-mercaptobenzothiazole, 2- (methylmercapto) benzothiazole, 2-aminobenzothiazole, 2-amino-6-methoxybenzothiazole, and 2-methyl. -5-chlorobenzothiazole, 2-hydroxybenzothiazole, 2-amino-6-methylbenzothiazole, 2-chlorobenzothiazole, 2,5-dimethylbenzothiazole, 6-nitro-2-mercaptobenzothiazole, 5-hydroxy -2-methylbenzothiazole, 2-benzothiazolethioacetic acid and the like.

  As the above-mentioned brightener or semi-brightener, there are some overlaps with the above-mentioned smoothing agent, but benzaldehyde, o-chlorobenzaldehyde, 2,4,6-trichlorobenzaldehyde, m-chlorobenzaldehyde, p-nitrobenzaldehyde, p-hydroxy. Benzaldehyde, furfural, 1-naphthaldehyde, 2-naphthaldehyde, 2-hydroxy-1-naphthaldehyde, 3-acenaphthaldehyde, benzylideneacetone, pyridideneacetone, furfurylideneacetone, cinnamaldehyde, anisaldehyde, salicylaldehyde, Various aldehydes such as crotonaldehyde, acrolein, glutaraldehyde, paraaldehyde, vanillin, triazine, imidazole, indole, quinoline, 2-vinylpyridine, aniline, phena Toroline, neocuproine, picolinic acid, thioureas, N- (3-hydroxybutylidene) -p-sulfanilic acid, N-butylidenesulfanilic acid, N-cinnamoylidenesulfanilic acid, 2,4-diamino-6- ( 2'-methylimidazolyl (1 ')) ethyl-1,3,5-triazine, 2,4-diamino-6- (2'-ethyl-4-methylimidazolyl (1')) ethyl-1,3,5 -Triazine, 2,4-diamino-6- (2'-undecylimidazolyl (1 ')) ethyl-1,3,5-triazine, phenyl salicylate, or benzothiazole, 2-mercaptobenzothiazole, 2- Methylbenzothiazole, 2-aminobenzothiazole, 2-amino-6-methoxybenzothiazole, 2-methyl-5-chlorobenzothiazole, 2-hydroxybenzothiazo 2, 2-amino-6-methylbenzothiazole, 2-chlorobenzothiazole, 2,5-dimethylbenzothiazole, 5-hydroxy-2-methylbenzothiazole, benzothiazoles such as 2-benzothiazolethioacetic acid, etc. It is done.

Examples of the pH adjuster include various acids such as hydrochloric acid and sulfuric acid, various bases such as aqueous ammonia, potassium hydroxide, and sodium hydroxide.
Examples of the buffer include dicarboxylic acids such as boric acids, phosphoric acids, ammonium chloride, oxalic acid, and succinic acid, and oxycarboxylic acids such as lactic acid and tartaric acid.
Examples of the conductive salt include sodium salts such as sulfuric acid, hydrochloric acid, phosphoric acid, sulfamic acid, and sulfonic acid, potassium salts, magnesium salts, ammonium salts, and amine salts. is there.
Examples of the preservative include boric acid, 5-chloro-2-methyl-4-isothiazolin-3-one, benzalkonium chloride, phenol, phenol polyethoxylate, thymol, resorcin, isopropylamine, and guaiacol.
Examples of the antifoaming agent include pluronic surfactants, higher aliphatic alcohols, acetylene alcohols and polyalkoxylates thereof.

In the plating bath of the present invention, the concentration of the various additives may be appropriately selected according to the method of use such as barrel plating, rack plating, high-speed continuous plating, rackless plating and the like.
When electroplating using the plating bath of the present invention, the bath temperature is preferably about 0 ° C. or higher, more preferably about 10 to 50 ° C. Cathode current density is preferably about 0.01~150A / dm ^2, about 0.1~30A / dm ² is more preferable.
Further, the pH of the bath can be in a wide range from acidic to almost neutral, but a range of weakly acidic to strongly acidic is particularly preferable.

  The present invention 6 is a method of electroplating using the lead-free tin-silver alloy-based or tin-copper-based alloy plating bath of the present invention 1-5, wherein the anode and the cathode are immersed in the tin alloy plating bath. The tin-silver-based alloy or tin containing a nonionic surfactant of a specific chemical structural type having the predetermined HLB as an essential component when electroplating using tin or a tin alloy as an anode and a substrate to be plated as a cathode -A lead-free tin-silver alloy or tin-copper alloy electroplating method in which bismuth is prevented from being deposited on the anode surface by using a copper alloy plating bath.

The electroplating method using the tin-silver-based alloy or tin-copper-based alloy plating bath of the present invention forms a plating film excellent in solderability, particularly when an electrical component or electronic component is to be plated. It is highly useful because it is excellent in safety.
There are no particular limitations on the electrical component or electronic component as the object to be plated, and specific examples thereof include semiconductor devices, printed circuit boards, flexible printed circuit boards, film carriers, ICs, connectors, switches, resistors, variable resistors, capacitors, Examples include a filter, an inductor, a thermistor, a crystal resonator, and a lead wire (see the present invention 7).
Moreover, there is no restriction | limiting in particular also about the film thickness of a plating film, However, Usually, about 0.1-20 micrometers is preferable.

Hereinafter, examples of the tin-silver alloy and tin-copper alloy electroplating bath of the present invention, the degree of prevention of substitutional precipitation of silver or copper when the tin anode is immersed in the plating bath, and the plating bath composition (silver or Copper concentration) evaluation test example, and the visual appearance of the electrodeposition film and the film composition evaluation test example when electroplating using the tin alloy plating bath will be sequentially described.
The present invention is not limited to the following examples and test examples, and it is needless to say that arbitrary modifications can be made within the scope of the technical idea of the present invention.

<< Examples of tin-silver based alloy and tin-copper based composite alloy electric alloy plating bath >>
Of the following Examples 1 to 23, Examples 1 to 12 are examples of a tin-silver alloy plating bath, and Examples 13 to 23 are examples of a tin-copper alloy plating bath. Among Examples 1 to 12, Example 10 is an example of a tin-silver-zinc alloy plating bath, Example 11 is an example of a tin-silver-indium alloy plating bath, and Example 12 is a tin-silver-copper alloy plating bath. The other examples are examples of a tin-silver alloy plating bath. Of Examples 13 to 23, Example 22 is an example of a tin-copper-zinc alloy plating bath, Example 23 is an example of a tin-copper-indium alloy plating bath, and the others are examples of a tin-copper alloy plating bath. . Among Examples 1 to 23, Examples 1, 10 to 13, and 22 to 23 are examples of using a nonionic surfactant of a specific chemical structural species having a predetermined HLB, and other examples are both predetermined HLB. It is a single use example of a nonionic surfactant of a specific chemical structural species having
On the other hand, among the following Comparative Examples 1 to 8, Comparative Examples 1 to 4 are examples of a tin-silver alloy plating bath, and of these, Comparative Example 1 is a blank that does not use a nonionic surfactant of a specific chemical structure type. Example, Comparative Example 2 is an example using a nonionic surfactant other than a specific chemical structural species, and Comparative Examples 3 to 4 are nonionic surfactants of a specific chemical structural species, but HLB deviates from a predetermined range. It is an example used. Comparative Examples 5 to 8 are examples of a tin-copper alloy plating bath. Among them, Comparative Example 5 is a blank example in which a nonionic surfactant having a specific chemical structure type is not used, and Comparative Example 6 is a specific chemical structure type. Examples using other nonionic surfactants, Comparative Examples 7 to 8 are nonionic surfactants of specific chemical structural species, but are examples using HLB deviating from a predetermined range. In the leftmost column of FIG. 1, the molar ratio of the surfactant (SAA) to silver or copper ions in each example and comparative example is shown. For example, in Example 1 below, the total molar concentration of the nonionic surfactant of a specific chemical structural species is (0.002 + 0.0008 =) 0.000028 mol / L and the silver concentration is 0.0097 mol / L. Therefore, the molar ratio of the surfactant to silver ions is 0.000028 / 0.000092 = 0.3.

(1) Example 1
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 130g / L
Thiourea 5g / L
Distyrenated phenol polyethoxylate (HLB7.3) 0.002 mol / L
Distyrenated phenol polyethoxylate (HLB15.2) 0.0008 mol / L

(2) Example 2
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
Thiourea 5g / L
Tristyrenated phenol polyethoxylate (HLB10.4) 0.0028 mol / L
Bisphenol A polyethoxylate (HLB15.4) 1g / L

(3) Example 3
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 60g / L
Silver methanesulfonate (as Ag ⁺ ) 2g / L
Methanesulfonic acid (as free acid) 150g / L
Thiourea 10g / L
Tristyrenated cresol polyethoxylate (HLB11.7) 0.0028 mol / L

(4) Example 4
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous ethanesulfonate (as Sn ²⁺ ) 60g / L
Silver ethanesulfonate (as Ag ⁺ ) 2g / L
Ethanesulfonic acid (as free acid) 130g / L
Thiourea 10g / L
Distyrenated cresol polyethoxylate (HLB8.2) 0.0037 mol / L
β-naphthol polyethoxylate (HLB16) 2g / L

(5) Example 5
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
Methylthiourea 4g / L
Tristyrenated cresol polyethoxylate (HLB7.7) 0.006 mol / L
Sodium triisopropylnaphthalenesulfonate 0.5g / L

(6) Example 6
A tin-silver alloy electroplating bath was constructed with the following composition.
2-hydroxyethanesulfonic acid stannous (as Sn ²⁺ ) 20 g / L
Silver 2-hydroxyethanesulfonate (as Ag ⁺ ) 0.2 g / L
2-hydroxyethanesulfonic acid (as free acid) 100 g / L
1,3-dimethylthiourea 2g / L
Tristyrenated cresol polyethoxylate (HLB12.2) 0.00093 mol / L
Dodecyltrimethylammonium chloride 0.3g / L

(7) Example 7
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
Thiourea 5g / L
Distyrenated cresol polyethoxylate (HLB13.6) 0.0000465 mol / L

(8) Example 8
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
Thiourea 5g / L
Distyrenated cresol polyethoxylate (HLB13.6) 0.00093 mol / L

(9) Example 9
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
Thiourea 5g / L
Distyrenated cresol polyethoxylate (HLB13.6) 0.0186 mol / L

(10) Example 10
A tin-silver-zinc alloy electroplating bath was constructed with the following composition.
2-hydroxypropane
-1 stannous sulfonate (as Sn ²⁺ ) 30g / L
2-hydroxypropane
-1-silver sulfonate (as Ag ⁺ ) 0.5 g / L
Zinc methanesulfonate (as Zn ²⁺ ) 3g / L
2-hydroxypropane-1-sulfonic acid (as free acid) 120 g / L
Thiourea 3g / L
Distyrenated cresol polyethoxylate (HLB12.5) 0.00092 mol / L
Distyrenated cresol polyethoxylate (HLB13.8) 0.00092 mol / L

(11) Example 11
A tin-silver-indium alloy electroplating bath was constructed with the following composition.
2-hydroxypropane
-1 stannous sulfonate (as Sn ²⁺ ) 30g / L
2-hydroxypropane
-1-silver sulfonate (as Ag ⁺ ) 0.5 g / L
Indium methanesulfonate (as In ³⁺ ) 1g / L
Thiourea 3g / L
2-hydroxypropane-1-sulfonic acid (as free acid) 120 g / L
Distyrenated cresol polyethoxylate (HLB12.5) 0.00092 mol / L
Distyrenated cresol polyethoxylate (HLB13.8) 0.00092 mol / L

(12) Example 12
A tin-silver-copper alloy electroplating bath was constructed with the following composition.
2-hydroxypropane
-1 stannous sulfonate (as Sn ²⁺ ) 60g / L
2-hydroxypropane
-1-silver sulfonate (as Ag ⁺ ) 1 g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
2-hydroxypropane-1-sulfonic acid (as free acid) 150 g / L
Thiourea 10g / L
Distyrenated cresol polyethoxylate (HLB12.5) 0.0025 mol / L
Distyrenated cresol polyethoxylate (HLB13.8) 0.002 mol / L

(13) Example 13
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
Methanesulfonic acid (as free acid) 130g / L
2,2'-dipyridyl 2.5 g / L
Distyrenated phenol polyethoxylate (HLB7.3) 0.002 mol / L
Distyrenated phenol polyethoxylate (HLB15.2) 0.0011 mol / L

(14) Example 14
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
2,2'-dipyridyl 2.5 g / L
Distyrenated phenol polyethoxylate (HLB11.9) 0.0027 mol / L
Bisphenol A polyethoxylate (HLB15.4) 1g / L

(15) Example 15
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 60g / L
Copper methanesulfonate (as Cu ²⁺ ) 2g / L
Methanesulfonic acid (as free acid) 150g / L
2,2'-dipyridyl 5g / L
Tristyrenated cresol polyethoxylate (HLB11.7) 0.003 mol / L

(16) Example 16
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous ethanesulfonate (as Sn ²⁺ ) 60g / L
Ethanesulfonic acid copper (as Cu ²⁺ ) 2g / L
Ethanesulfonic acid (as free acid) 130g / L
2,2'-dipyridyl 5g / L
Distyrenated cresol polyethoxylate (HLB8.2) 0.0038 mol / L
β-naphthol polyethoxylate (HLB16) 2g / L

(17) Example 17
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
2,2'-dipyridyl 2.5 g / L
Tristyrenated cresol polyethoxylate (HLB7.7) 0.0063 mol / L
Sodium triisopropylnaphthalenesulfonate 0.5g / L

(18) Example 18
A tin-copper alloy electroplating bath was constructed with the following composition.
2-hydroxyethanesulfonic acid stannous (as Sn ²⁺ ) 20 g / L
2-hydroxyethanesulfonic acid copper (as Cu ²⁺ ) 0.2 g / L
2-hydroxyethanesulfonic acid (as free acid) 100 g / L
2,2'-dithiodiethanol 0.5g / L
Tristyrenated cresol polyethoxylate (HLB12.2) 0.0016 mol / L
Dodecyltrimethylammonium chloride 0.3g / L

(19) Example 19
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
2,2'-dipyridyl 2.5 g / L
Distyrenated cresol polyethoxylate (HLB13.6) 0.000785 mol / L

(20) Example 20
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
2,2'-dipyridyl 2.5 g / L
Distyrenated cresol polyethoxylate (HLB13.6) 0.0016 mol / L

(21) Example 21
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
Methanesulfonic acid (as free acid) 120g / L
2,2'-dipyridyl 2.5 g / L
Distyrenated cresol polyethoxylate (HLB13.6) 0.0205 mol / L

(22) Example 22
A tin-copper-zinc alloy electroplating bath was constructed with the following composition.
2-hydroxypropane
-1 stannous sulfonate (as Sn ²⁺ ) 30g / L
2-hydroxypropane
-1- Copper sulfonate (as Cu ²⁺ ) 0.5 g / L
Zinc methanesulfonate (as Zn ²⁺ ) 3g / L
2-hydroxypropane-1-sulfonic acid (as free acid) 120 g / L
2,2'-dithiodiethanol 1.25g / L
Distyrenated cresol polyethoxylate (HLB12.5) 0.0014 mol / L
Distyrenated cresol polyethoxylate (HLB13.8) 0.001 mol / L

(23) Example 23
A tin-copper-indium alloy electroplating bath was constructed with the following composition.
2-hydroxypropane
-1 stannous sulfonate (as Sn ²⁺ ) 30g / L
2-hydroxypropane
-1- Copper sulfonate (as Cu ²⁺ ) 0.5 g / L
Indium methanesulfonate (as In ³⁺ ) 1g / L
2,2'-dithiodiethanol 1.25g / L
2-hydroxypropane-1-sulfonic acid (as free acid) 120 g / L
Distyrenated cresol polyethoxylate (HLB12.5) 0.0014 mol / L
Distyrenated cresol polyethoxylate (HLB13.8) 0.001 mol / L

(24) Comparative Example 1
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 130g / L
Thiourea 5g / L

(25) Comparative Example 2
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 130g / L
Thiourea 5g / L
Bisphenol A polyethoxylate (HLB15.4) 3g / L

(26) Comparative Example 3
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 60g / L
Silver methanesulfonate (as Ag ⁺ ) 2g / L
Methanesulfonic acid (as free acid) 150g / L
Thiourea 10g / L
Tristyrenated cresol polyethoxylate (HLB15.2) 0.0037 mol / L

(27) Comparative Example 4
A tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 60g / L
Silver methanesulfonate (as Ag ⁺ ) 2g / L
Methanesulfonic acid (as free acid) 150g / L
Thiourea 10g / L
Tristyrenated cresol polyethoxylate (HLB4.9) 0.00185 mol / L
Nonylphenol polyethoxylate (HLB15.0) 8g / L

(28) Comparative Example 5
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
Methanesulfonic acid (as free acid) 130g / L
2,2'-dipyridyl 2.5 g / L

(29) Comparative Example 6
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Copper methanesulfonate (as Cu ²⁺ ) 1g / L
Methanesulfonic acid (as free acid) 130g / L
2,2'-dipyridyl 2.5 g / L
Octylphenol polyethoxylate (HLB15) 3g / L

(30) Comparative Example 7
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 60g / L
Copper methanesulfonate (as Cu ²⁺ ) 2g / L
Methanesulfonic acid (as free acid) 150g / L
2,2'-dipyridyl 5g / L
Tristyrenated cresol polyethoxylate (HLB14.9) 0.0022 mol / L

(31) Comparative Example 8
A tin-copper alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 60g / L
Copper methanesulfonate (as Cu ²⁺ ) 2g / L
Methanesulfonic acid (as free acid) 150g / L
2,2'-dipyridyl 5g / L
Tristyrenated cresol polyethoxylate (HLB6.0) 0.0022 mol / L
Bisphenol A polyethoxylate (HLB15.4) 9g / L

Therefore, the tin anode is immersed in each of the tin-silver alloy or tin-copper alloy plating baths of Examples 1 to 23 and Comparative Examples 1 to 8, and the degree of prevention of substitutional precipitation of silver or copper on the tin anode is determined. An evaluation test was conducted on the stability of the plating bath composition.
<< Evaluation Test Example A of Substrate Deposition Prevention on Anode and Stability of Plating Bath Composition When Anode is Dipped in Plating Bath >>
A tin electrode plate (60 mm × 20 mm) was added to 100 mL of each of the tin-silver alloy or tin-copper alloy plating baths of Examples 1 to 23 and Comparative Examples 1 to 8 heated to 35 ° C. for 8 hours without stirring. After the immersion, the appearance of the tin anode was visually observed, and the silver or copper ion concentration in the plating bath at the time point of 8 hours was measured by atomic absorption spectrometry, and converted into a residual ratio with respect to the initial concentration.

FIG. 1 shows the result.
(1) About the tin-silver alloy plating bath According to FIG. 1, in the comparative example 1 of the blank example not containing the nonionic surfactant of the specific chemical structural type of the present invention, the tin anode is blackened by substitution deposition of silver. The color changed, and the comparative example 2 using normal nonionic surfactants other than the specific chemical structural species also turned black. Further, in Comparative Example 3 containing a nonionic surfactant having a specific chemical structural species of the present invention, the HLB of which exceeds the proper range, or Comparative Example 4 in which the HLB is lower than the proper range, silver substitution deposition is It turned black over a wide part of the anode, and only a part of the anode retained the metallic luster.
Incidentally, the remaining ratio of silver in the plating bath after 8 hours from the start of the non-energized immersion of the anode is only 31 to 39% in Comparative Examples 1 and 2, and the silver is rapidly consumed by substitutional precipitation. I confirmed. Furthermore, even in Comparative Examples 3 to 4, the residual ratio was only 54 to 62%.
On the other hand, in Examples 1 to 12, substitutional deposition of silver was well prevented, and the anode had a metallic luster over the entire surface or most of tin. This point is also supported by the fact that the residual rate of silver in the plating bath after 8 hours in Examples 1 to 13 showed a high ratio of 71 to 97%.

When the Examples 1-12 are described in detail, when the concentration (weight ratio) of the surfactant of the specific chemical structural species with respect to silver is two times or higher, the entire surface of the tin anode maintained a metallic luster. As in Example 7, when the concentration was relatively low, part of the anode surface turned black. In general, since silver has a large electrode potential and is easily inclined to be deposited from the bath, it is not easy to prevent substitution deposition on the entire surface of the anode when the concentration of the surfactant of the present invention is low. It is presumed that silver was deposited by substitution.
In Examples 1 to 9, which are tin-silver binary alloy plating baths, the residual ratio of silver in the bath was high, and silver substitution deposition at the anode could be effectively prevented. However, tin-silver-zinc As shown in an alloy plating bath (Example 10), a tin-silver-indium alloy plating bath (Example 11), and a tin-silver-copper alloy plating bath (Example 12), a tin-silver based ternary alloy plating Even in a bath, when a surfactant of a specific chemical structural species of the present invention is added, it can exhibit an excellent effect in preventing substitution substitution of silver as supported by a high silver residual ratio of 88 to 94%. It was revealed.

As described above, when Examples 1 to 12 are compared with Comparative Examples 1 and 2, in the tin-silver alloy electroplating bath, in order to effectively prevent silver substitution deposition on the tin or tin alloy anode, It has become clear that it is important to add the nonionic surfactant of the specific chemical structural species of the present invention to the plating bath.
Moreover, when Examples 1-12 are compared with Comparative Examples 3-4, even if it is a nonionic surfactant of the specific chemical structure type selected by this invention, substitutional precipitation of silver on a tin or tin alloy anode is carried out. In order to prevent effectively, it became clear that it was necessary to have HLB of a predetermined field further.

(2) About a tin-copper alloy plating bath According to FIG. 1, a comparative example 5 of a blank example not containing a nonionic surfactant of a specific chemical structure type of the present invention, or a normal other than a specific chemical structure type In Comparative Example 6 using the nonionic surfactant, the tin anode was changed to a bronze color by substitution deposition of copper, and the nonionic surfactant of the specific chemical structure type of the present invention was included, but its HLB was in an appropriate range. In Comparative Examples 7 to 8 that deviate from the above, copper substitution deposition spreads over a wide part of the anode, and only a part of the anode retained the metallic luster.
On the other hand, in Examples 13 to 23, the substitutional deposition of copper was well prevented, and the entire or most of the tin retained the metallic luster in the anode. This point is supported by the fact that the residual ratio of copper in the plating bath after 8 hours in Examples 13 to 23 showed a high ratio of 76 to 98%.
That is, as in the case of the above-described tin-silver alloy plating bath, when Examples 13 to 23 are compared with Comparative Examples 5 to 8, in the tin-copper alloy plating bath, the copper in the tin or tin alloy anode In order to effectively prevent displacement precipitation, it is clear that it is necessary to add a nonionic surfactant having a specific chemical structural species of the present invention and having a predetermined region of HLB to the plating bath. became.
Moreover, as the concentration of the surfactant of the present invention increases, the residual ratio of copper in the bath (when 8 hours elapses) is further increased, which contributes better to prevention of substitutional precipitation of copper at the tin or tin alloy anode. The surfactant of the present invention is added not only in the case of a tin-copper binary alloy plating bath but also in the case of a tin-copper-zinc alloy or tin-copper-indium alloy ternary alloy plating bath. Then, it was recognized that prevention of substitutional precipitation of copper can be effectively prevented so that a high copper residual ratio of 93 to 94% is supported.

Thus, in the electroplating bath of the embodiment containing the nonionic surfactant of a specific chemical structural type having a predetermined HLB, when the tin or tin alloy anode is immersed in the bath without current, silver or silver at the anode Copper displacement precipitation can be effectively prevented, and the composition of the plating bath can be stabilized.
Therefore, when the electroplating is performed using the tin-silver alloy plating bath or the tin-copper alloy plating bath to which the surfactant of the present invention is added, the superiority or inferiority of the visual appearance of the obtained electrodeposition coating is evaluated. At the same time, the composition of the electrodeposition film (the content of silver or copper in the film) was examined.

<< Evaluation Test Example B for Visual Appearance and Composition of Electrodeposited Film Obtained from Bath by Electroplating >>
(1) Tin-silver alloy electroplating (Example 24)
First, a tin-silver alloy electroplating bath was constructed with the following composition.
Stannous methanesulfonate (as Sn ²⁺ ) 50g / L
Silver methanesulfonate (as Ag ⁺ ) 1g / L
Methanesulfonic acid (as free acid) 130g / L
Thiourea 5g / L
Distyrenated phenol polyethoxylate (HLB7.3) 0.002 mol / L
Distyrenated phenol polyethoxylate (HLB15.2) 0.0008 mol / L
β-naphthol polyethoxylate (HLB16) 1g / L
2-mercapobenzobenzothiazole 0.1 g / L
Hydroquinone 1g / L

Next, using the tin-silver alloy electroplating bath of Example 24, electroplating was performed on the copper plate under the following conditions, and the visual appearance of the obtained electrodeposition film and the composition of silver in the film were examined.
[Conditions for electroplating]
Cathode current density: 3 A / dm ²
Bath temperature: 35 ° C
Stirring: Cathode locker (1m / min)
As a result, the silver content of the electrodeposition film obtained from the plating bath of Example 24 was 3.1% by weight, and the film was uniform and dense, and exhibited a good appearance with no uneven color. In Comparative Example 1, which is a tin-silver alloy plating bath that does not contain a nonionic surfactant having a specific chemical structure of the present invention, only a rough plating film was obtained.

(2) About tin-copper alloy electroplating (Example 25)
First, a tin-copper alloy electroplating bath was constructed with the following composition.
Stannous ethanesulfonate (as Sn ²⁺ ) 60g / L
Ethanesulfonic acid copper (as Cu ²⁺ ) 2g / L
Ethanesulfonic acid (as free acid) 130g / L
2,2'-dipyridyl 5g / L
Tristyrenated cresol polyethoxylate (HLB12.2) 0.00185 mol / L
Benzalacetone 0.1 g / L
Benzoic acid 0.5g / L
Dodecyl alcohol polyethoxylate (HLB14.9) 0.3g / L
Acrylic acid 0.02g / L
Hydroquinone 0.8g / L

Next, using the tin-copper alloy electroplating bath of Example 25, electroplating was performed on the copper plate under the following conditions, and the visual appearance of the obtained electrodeposition film and the composition of silver in the film were examined.
[Conditions for electroplating]
Cathode current density: 5 A / dm ²
Bath temperature: 30 ° C
Stirring: Cathode locker (1m / min)
As a result, the copper content of the electrodeposition film obtained from the plating bath of Example 25 was 3.8% by weight, and the film was uniform and dense, and exhibited a good appearance with no uneven color. In Comparative Example 5, which is a tin-copper alloy plating bath that does not contain a nonionic surfactant having a specific chemical structure of the present invention, only a rough plating film was obtained.
As described above, when a nonionic surfactant of a specific chemical structural type having a predetermined HLB of the present invention is added to a tin-silver alloy or tin-copper alloy electroplating bath, the silver or copper on the tin anode is added. It was confirmed that the precipitation of the electrodeposition film obtained from the plating bath was also excellent because the displacement precipitation was effectively prevented and the composition of the plating bath could be stabilized.

Visual appearance of tin anode and residual silver or copper in bath when tin anode was immersed in each tin-silver alloy or tin-copper alloy plating bath of Examples 1-23 and Comparative Examples 1-8 for a predetermined time It is a graph which shows the evaluation test result of a rate.

Claims (7)

Lead-free containing a soluble stannous salt, a soluble silver salt, and at least one acid selected from an inorganic acid composed of hydrochloric acid, sulfuric acid, borohydrofluoric acid, an organic sulfonic acid, and an organic acid composed of carboxylic acid In a tin-silver alloy electroplating bath,
Distyrenated phenol polyalkoxylate with HLB 7.3-15.2, Tristyrenated phenol polyalkoxylate with HLB 7.0-10.4, Distyrenated cresol polyalkoxy with HLB 8.2-15.0 Addition of at least one nonionic surfactant comprising a tristyrenated cresol polyalkoxylate having a rate, HLB of 7.7 to 13.9, and substitution deposition of silver on the anode surface made of tin or tin alloy A lead-free tin-silver alloy electroplating bath characterized by   The lead-free tin-silver alloy according to claim 1, wherein the tin-silver alloy is a tin-silver-copper alloy, and the electroplating bath contains a soluble copper salt as a copper source. Electroplating bath. Lead-free containing a soluble stannous salt, a soluble copper salt, and at least one acid selected from an inorganic acid consisting of hydrochloric acid, sulfuric acid, borohydrofluoric acid, an organic sulfonic acid, and an organic acid consisting of a carboxylic acid In the tin-copper alloy electroplating bath,
Distyrenated phenol polyalkoxylate with HLB 7.3-15.2, Tristyrenated phenol polyalkoxylate with HLB 7.0-10.4, Distyrenated cresol polyalkoxy with HLB 8.2-15.0 Addition of at least one nonionic surfactant comprising a tristyrenated cresol polyalkoxylate having a rate, HLB of 7.7 to 13.9, and substitution deposition of copper on the anode surface made of tin or tin alloy A lead-free tin-copper alloy electroplating bath characterized by   A tin-silver alloy or a tin-copper alloy is a multi-component alloy further containing another metal, and the electroplating bath contains a soluble salt of the other metal, and the other metal is zinc, indium, antimony, The lead-free tin-silver alloy or tin-copper alloy according to any one of claims 1 to 3, which is at least one selected from the group consisting of iron, cobalt, nickel, and iridium. Electroplating bath.   Furthermore, it contains at least one of a surfactant, a complexing agent, an antioxidant, a smoothing agent, a semi-brightening agent, a brightening agent, a conductive salt, and a pH adjusting agent. The lead-free tin-silver alloy or tin-copper alloy electroplating bath according to item 1. When the anode and the cathode are immersed in a lead-free tin alloy plating bath, and tin or tin alloy is used as an anode and the object to be plated is used as a cathode,
Lead-free tin-, which can prevent silver or copper from being deposited on the anode surface by using the tin alloy electroplating bath according to any one of claims 1 to 5. Silver-based alloy or tin-copper-based alloy electroplating method.   An electronic component in which a lead-free tin-silver alloy or tin-copper alloy film is formed on the substrate using the tin alloy electroplating bath according to any one of claims 1 to 5.

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