JP3532046B2 - Non-cyanated silver plating bath - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating technique, and more particularly, to a non-cyan type non-cyan layer for forming a tin-silver multi-layered film having good solderability to tin-silver brazing filler metal, particularly good aging characteristics. Regarding displacement silver plating bath.

[0002]

2. Description of the Related Art Joining with a solder (brazing material) having a basic composition of tin-lead is widely used as an indispensable technique in the electronic industry. In order to perform soldering quickly and reliably, it is necessary to apply a film with good solderability to the parts to be soldered in advance.As this solderability film, a tin-lead alloy plating film is generally used. It's being used.

However, in recent years, there is concern about the effects of lead on health and the environment, and the idea of controlling tin-lead solder containing harmful lead is rapidly spreading. Considering industrial production conditions and usage conditions, there is no lead-free solder that has the property of being able to replace tin-lead solder, and research and development is being conducted mainly in Japan, Europe and the United States. is there. Although tin is considered to be used as the first element as an alternative to tin-lead solder,
As the second element, silver, bismuth, copper, indium, antimony, zinc, and the like are listed as candidates, and binary alloys thereof or multicomponent alloys to which a third element is further added are listed as candidates. Among them, the tin-silver alloy is one of the most promising alternative alloy candidates.

Corresponding to the alternative solder, it is necessary to change the plating film for soldering (solderability film) to one that does not contain lead. As a solderable film other than the tin-lead alloy plating film, as the single metal film, tin,
Gold, silver, and palladium are the targets of study. When using a tin alloy film, it is desirable that the composition is close to that of a brazing filler metal. Therefore, when using a tin-silver brazing filler metal, a tin-silver alloy plating film is used. Although it is considered as a subject for consideration, it has not yet been put to practical use.

Among these objects to be studied, tin alone has a problem that whiskers are apt to be generated, and noble metal plating of gold, silver, palladium or the like cannot be plated to a thickness sufficient to provide sufficient corrosion resistance. There is a problem in terms of cost.

On the other hand, since the tin-silver alloy plating film exhibits good solderability to tin-silver solder,
The inventors of the present invention have made diligent studies on the tin-silver alloy plating bath and applied for a patent (for example, JP-A-8-143481), but it is difficult to control the alloy composition in the plating film. There are some problems that cannot be avoided.
As a method for facilitating control of the film composition, the inventors have also formed a silver film on the tin plating by electroplating or electroless plating to suppress the generation of whiskers and have a solderability better than that of the tin-only film. It has been found that the resulting film is excellent in, especially, its aging characteristics.

[0007]

As a method of applying a silver plating film on a tin plating film, in addition to the above electroplating or electroless plating, by utilizing the difference in ionization tendency, a substitution reaction of tin metal and silver ion is carried out. A method of performing displacement plating by In substitutional plating, the tin film itself to be plated serves as a silver reducing agent in electroplating which requires energization or electroless plating which requires the supply of a reducing agent, so the process or its management is easier.

Substitution precipitation of silver on metallic tin is a reaction that can easily occur, and when a cyan bath is used, a good substitution film can be obtained without requiring special additives. . However, it is not desirable to use a cyan bath because of environmental and pollution problems. On the other hand, it is not easy to deposit dense and uniform silver on tin from a non-cyan bath at an appropriate rate, mainly because of the problem of stability of silver ions and eluted tin ions in the bath. I can't find it.

[0009]

Means for Solving the Problems The inventor of the present invention uses monovalent silver ions, appropriately selects the concentration of the silver ions, and at the same time provides acid radicals and / or complexes for keeping the silver ions stable. It was found that a dense and uniform silver film can be deposited on a tin plating film from a non-cyan bath by appropriately selecting and adding an agent, and further, when soldering with tin-silver solder It has been found that the film exhibits superior solderability as compared with a film containing tin alone, and in particular, its time-dependent characteristics are excellent.

Further, by appropriately adding a complexing agent for preventing the substitutionally eluted tin from precipitating,
It has been found that it is possible to prevent impurities particles such as tin hydroxide from being mixed into the substitutionally deposited silver film, and to prolong the life of the bath.

Furthermore, it is possible to control the deposition of a dense and uniform silver film by appropriately adding a pH buffer.
In addition, they have found that the addition of a tin antioxidant can prevent the substitutionally eluted tin from being naturally oxidized and precipitating as tetravalent tin and prolonging the life of the plating bath.

By combining the silver-substituted film and the lower tin film thus obtained, the resulting film is applied to electric / electronic circuit parts to obtain a tin-silver solder and a tin-silver plating film. It is possible to use tin in combination, and thus tin-which has problems in terms of environment, hygiene and pollution-
It has made it possible to replace lead solder and has solved the alternative solder problem.

SUMMARY OF THE INVENTION The present invention is selected from monovalent silver ions and the following (A) to (J) for stabilizing the silver ions in a bath to obtain a smooth and dense substitutional deposition film of silver. and one or more complexing agents of silver which, in order to prevent the tin substituted eluted precipitates
One of tin complexing agents selected from the following (a) to (j)
Is two or more, and the following (1), (3), (5) to (13)
One or more silver substitution precipitation inhibitors selected from
And it provides a non-cyanide substitution silver plating bath for depositing a substitution film of silver on the tin or tin alloy characterized in that it comprises a.

(A) The following inorganic acid ions: nitrate ions,
Nitrite ion, sulfate ion, sulfite ion, bisulfite ion, metabisulfite ion, chlorine ion, chlorate ion, perchlorate ion, bromine ion, bromate ion, iodine ion, iodate ion, borofluoride ion, keifu Acid ion, sulfamate ion, thiosulfate ion,
Thiocyanate ion.

(B) Ammonium ion, ammonium persulfate ion.

(C) Acetate ion.

(D) The following general formulas (i), (ii) and /
Alternatively, a sulfonic acid ion represented by (iii).

(I) General formula

[Chemical formula 23] [Where R is a C ₁ -C ₁₂ alkyl group or C ₁ -C ₃
Represents an alkenyl group, and hydrogen of R may be substituted with a hydroxyl group, an alkyl group, an aryl group, an alkylaryl group, a carboxyl group or a sulfonic acid group in the range of 0 to 3, and Can be in position. ] Aliphatic sulfonic acid represented by these.

(Ii) General formula

[Chemical formula 24] [Wherein, R represents an alkyl group of C ₁ -C _3. X represents chlorine and / or fluorine halogen, which may be present at any position of the R, and the substitution number n1 of the halogen substituted with the hydrogen of the R is from 1 to all the hydrogens coordinated to the R. Represents up to saturated and substituted halogen species of 1
There are two types. The hydroxyl group may be located at any position of the R, and the number of substitutions n2 of the hydroxyl group substituted with the hydrogen of the R is n2.
Is 0 or 1. Y represents a sulfonic acid group, which may be present at any position of the R, and the substitution number n3 of the sulfonic acid group represented by Y is in the range of 0 to 2. ] The halogenated alkane sulfonic acid or halogenated alkanol sulfonic acid represented by these.

(Iii) General formula

[Chemical 25] [Where X represents a hydroxyl group, an alkyl group, an aryl group, an alkylaryl group, an aldehyde group, a carboxyl group, a nitro group, a mercapto group, a sulfonic acid group or an amino group, or two Xs together with a benzene ring Can form a naphthalene ring, and the substitution number n of the group is an integer of 0 to 3. ] The aromatic sulfonic acid represented by these.

(E) General formula

[Chemical formula 26] [Here, X represents oxygen or sulfur, and Ra and Rb each independently represent hydrogen, an amino group, or C _{1 to} C ₅ alkyl. Rc and Rd are each independently hydrogen or C _{1 to} C
₅ represents alkyl, alkenyl or phenyl, and hydrogen of the alkyl, alkenyl and / or phenyl may be substituted with a hydroxyl group or an amino group, monomethyl or dimethylamino group, and Rc and Rd are combined to form a ring. Good. ] The urea shown by these, or thiourea, or thioacetamide, or those derivatives.

(F) General formula

[Chemical 27] [However, Ra, Rb, Rc, Rd is hydrogen, alkyl (C ₁ ~C ₅₎ groups, the hydrogen of the alkyl group may be substituted with a hydroxyl group. ] The hydantoin compound represented by these.

(G) General formula

[Chemical 28] [However, Ra, Rb, Rc, and Rd each independently represent hydrogen or a C _{1 to} C ₅ alkyl group or alkoxy group. ] Succinimide (succinimide) or maleic imide and its derivative shown by these.

(H) General formula

[Chemical 29] [However, Ra, Rb, and Rc each independently represent hydrogen, a hydroxyl group, or C _{1 to} C ₅ alkyl, and the hydrogen of the alkyl group may be substituted with a hydroxyl group, an amino group, or chlorine. The groups may be bonded to each other to form a ring. ] The amine shown by these, and those salts.

(I) General formula

[Chemical 30] [Wherein R represents an alkylene group (C _{1 to} C ₅ ), and hydrogen of the alkylene group may be substituted with an amino group,
Further, it may be bonded to an acetyl group via the amino group. ] The thiocarboxylic acid or thiosulfonic acid represented by these.

(J) General formula

[Chemical 31] [Here, X represents oxygen, nitrogen or sulfur, and Y represents carbon or nitrogen. Z is hydrogen when X is nitrogen and is absent when oxygen or sulfur. A represents hydrogen or thiol and is absent when Y is nitrogen. Hydrogen on the benzene ring may be substituted with a methoxy group or ethoxy. ] The benzotriazole represented by these, benzothiazole, benzimidazole, or benzoxazole, and those derivatives.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION In the non-cyan type silver displacement plating bath on the tin film of the present invention, any known compound can be used as a source of monovalent silver ions.
For example, silver oxide, silver nitrate, silver sulfate, silver chloride, silver bromide, silver iodide, silver benzoate, silver sulfamate, silver citrate,
Silver lactate, silver mercaptosuccinate, silver phosphate, silver trifluoroacetate, silver pyrophosphate, 1-hydroxyethane-1,
1-bisphosphonate silver, or the following general formulas (i) and (i
i) a silver salt of an aliphatic sulfonic acid represented by, for example, silver methanesulfonate, silver sulfosuccinate, silver trifluoromethanesulfonate, or a silver salt of an aromatic sulfonic acid represented by the following general formula (iii), for example: Silver p-toluenesulfonate, silver sulfobenzoate and the like can be used alone or in an appropriate mixture.

(I) General formula

[Chemical 32] [Where R is a C ₁ -C ₁₂ alkyl group or C ₁ -C ₃
Represents an alkenyl group, and hydrogen of R may be substituted with a hydroxyl group, an alkyl group, an aryl group, an alkylaryl group, a carboxyl group or a sulfonic acid group in the range of 0 to 3, and Can be in position. ] The aliphatic sulfonic acid represented by these.

(Ii) General formula

[Chemical 33] [Wherein, R represents an alkyl group of C ₁ -C _3. X represents chlorine and / or fluorine halogen, which may be present at any position of the R, and the substitution number n1 of the halogen substituted with the hydrogen of the R is from 1 to all the hydrogens coordinated to the R. Represents up to saturated and substituted halogen species of 1
There are two types. The hydroxyl group may be located at any position of the R, and the number of substitutions n2 of the hydroxyl group substituted with the hydrogen of the R is n2.
Is 0 or 1. Y represents a sulfonic acid group, which may be present at any position of the R, and the substitution number n3 of the sulfonic acid group represented by Y is in the range of 0 to 2. ] The halogenated alkane sulfonic acid or halogenated alkanol sulfonic acid represented by these.

(Iii) general formula

[Chemical 34] [Where X represents a hydroxyl group, an alkyl group, an aryl group, an alkylaryl group, an aldehyde group, a carboxyl group, a nitro group, a mercapto group, a sulfonic acid group or an amino group, or two Xs together with a benzene ring Can form a naphthalene ring, and the substitution number n of the group is an integer of 0 to 3. ] The aromatic sulfonic acid represented by these.

The amount of the silver compound used is suitably about 0.01 to 50 g / l, preferably about 0.05 to 10 g / l, as the monovalent silver content. If the amount used is insufficient, it will be difficult to obtain the deposition rate required for industrial operation, and if the amount used is excessive, the intended purpose of obtaining a desired homogeneous, smooth and dense substituted silver film will not be achieved.

In the present displacement plating bath, a compound selected from the following (A) to (J) or a compound selected from the following (A) to (J) in order to stabilize monovalent silver ions in the bath and obtain a smooth and dense substitutional deposition film of silver. Ions and the like can be used alone or in an appropriate mixture.

(A) The following inorganic acid ions: nitrate ions,
Nitrite ion, sulfate ion, sulfite ion, bisulfite ion, metabisulfite ion, chlorine ion, chlorate ion, perchlorate ion, bromine ion, bromate ion, iodine ion, iodate ion, borofluoride ion, keifu Acid ion, sulfamate ion, thiosulfate ion,
Thiocyanate ion.

(B) Ammonium ion, ammonium persulfate ion.

(C) Acetate ion.

(D) The following general formulas (i), (ii) and /
Alternatively, a sulfonic acid ion represented by (iii).

(I) General formula

[Chemical 35] [Where R is a C ₁ -C ₁₂ alkyl group or C ₁ -C ₃
Represents an alkenyl group, and hydrogen of R may be substituted with a hydroxyl group, an alkyl group, an aryl group, an alkylaryl group, a carboxyl group or a sulfonic acid group in the range of 0 to 3, and Can be in position. ] The aliphatic sulfonic acid represented by these.

(Ii) General formula

[Chemical 36] [Wherein, R represents an alkyl group of C ₁ -C _3. X represents chlorine and / or fluorine halogen, which may be present at any position of the R, and the substitution number n1 of the halogen substituted with the hydrogen of the R is from 1 to all the hydrogens coordinated to the R. Represents up to saturated and substituted halogen species of 1
There are two types. The hydroxyl group may be located at any position of the R, and the number of substitutions n2 of the hydroxyl group substituted with the hydrogen of the R is n2.
Is 0 or 1. Y represents a sulfonic acid group, which may be present at any position of the R, and the substitution number n3 of the sulfonic acid group represented by Y is in the range of 0 to 2. ] The halogenated alkane sulfonic acid or halogenated alkanol sulfonic acid represented by these.

(Iii) general formula

[Chemical 37] [Where X represents a hydroxyl group, an alkyl group, an aryl group, an alkylaryl group, an aldehyde group, a carboxyl group, a nitro group, a mercapto group, a sulfonic acid group or an amino group, or two Xs together with a benzene ring Can form a naphthalene ring, and the substitution number n of the group is an integer of 0 to 3. ] The aromatic sulfonic acid represented by these.

(E) General formula

[Chemical 38] [Where X represents oxygen or sulfur, and Ra and Rb are
Independently hydrogen, amino group or C₁ ~ C_Five The alkyl
Represent Rc and Rd are each independently hydrogen or C ₁ ~ C
_Five Of alkyl, alkenyl or phenyl,
The hydrogen of the alkyl, alkenyl and / or phenyl is a hydroxyl group or
Is an amino group, monomethyl or dimethylamino group
Rc and Rd may be combined to form a ring.
Good. ] Or urea or thiourea or thioacetoa
Mido or their derivatives.

(F) General formula

[Chemical Formula 39] [However, Ra, Rb, Rc, Rd is hydrogen, alkyl (C ₁ ~C ₅₎ groups, the hydrogen of the alkyl group may be substituted with a hydroxyl group. ] The hydantoin compound represented by these.

(G) General formula

[Chemical 40] [However, Ra, Rb, Rc, and Rd each independently represent hydrogen or a C _{1 to} C ₅ alkyl group or alkoxy group. ] Succinimide (succinimide) or maleic imide and its derivative shown by these.

(H) General formula

[Chemical 41] [However, Ra, Rb, and Rc each independently represent hydrogen, a hydroxyl group, or C ₁ -C ₅ alkyl, and the hydrogen of the alkyl group may be substituted with a hydroxyl group, an amino group, or chlorine. The groups may be bonded to each other to form a ring. ] The amine shown by these, and those salts.

(I) General formula

[Chemical 42] [Wherein R represents an alkylene group (C _{1 to} C ₅ ), and hydrogen of the alkylene group may be substituted with an amino group,
Further, it may be bonded to an acetyl group via the amino group. ] The thiocarboxylic acid or thiosulfonic acid represented by these.

(J) General formula

[Chemical 43] [Here, X represents oxygen, nitrogen or sulfur, and Y represents carbon or nitrogen. Z is hydrogen when X is nitrogen and is absent when oxygen or sulfur. A represents hydrogen or thiol and is absent when Y is nitrogen. Hydrogen on the benzene ring may be substituted with a methoxy group or ethoxy. ] The benzotriazole represented by these, benzothiazole, benzimidazole, or benzoxazole, and those derivatives.

The preferred examples among those represented by the general formula are as follows.

Examples of general formula (D) represented by (i) and (ii) include methanesulfonic acid, sulfosuccinic acid and trifluoromethanesulfonic acid.

Examples of the general formula (D) (iii) include p-toluenesulfonic acid and sulfobenzoic acid.

Examples of the general formula (E) include imidazolidinone, 2-imidazolidinethione, thiourea,
Trimethylthiourea, N, N'-di-n-butylthiourea, tetramethylthiourea, 1-allyl-2-thiourea,
N, N'diethylthiourea, 1,3-bis (dimethylaminopropyl) -2-thiourea, N, N dimethylthiourea, N, N-dimethylolurea, thiosemicarbazide,
4-phenyl-3-thiosemicarbazide, 2-thiobarbituric acid, thioacetamide and the like can be mentioned.

Examples of the general formula (F) include hydantoin, 5-n-propylhydantoin, 5,5-dimethylhydantoin and the like.

As an example represented by the general formula (G), 2,
2-dimethyl succinimide, 2-methyl-2-ethyl succinimide, 2-methyl succinimide, 2-ethyl succinimide, 1,1,2,2-tetramethyl succinimide, 1,1, 2-trimethylsuccinimide,
Examples thereof include 2-butyl succinimide, 2-ethyl maleic imide, 1-methyl-2-ethyl maleic imide, and 2-butyl maleic imide.

Examples of the general formula (H) include ethylenediamine, ethylamine isopropylamine, n-
Butylamine, isobutylamine, dipropylamine,
Examples thereof include dibutylamine, diethylamine, monoethanolamine, diethanolamine, triethanolamine N-methylethanolamine, 2-amino-2- (hydroxymethyl) -1,3-propanediol, 2-chloroethylammonium chloride and the like.

Examples of the general formula (I) include mercaptosuccinic acid, 3-mercaptopropionic acid, mercaptoacetic acid, 2-mercaptopropionic acid, penicillamine, 3-mercaptopropanesulfonic acid, acetylcystine and cystine. Can be mentioned.

Examples of the general formula (J) include benzotriazole, 2-mercaptobenzothiazole, 6
-Ethoxy-2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole and the like can be mentioned.

The amount used is appropriately selected according to the kind of the acid radical or the complexing agent, but is appropriately about 1 to 20 mol, preferably 2 to 15 mol, per 1 mol of silver in the bath.
It is about molar. A lack of the amount used does not achieve the intended purpose of allowing the silver ions to exist stably in the bath, and an excess of the amount excessively accelerates the dissolution of the tin film, resulting in uniform, smooth and dense silver substitution. It may not achieve its intended purpose of obtaining a film.

In the plating bath used in the present invention, a tin complex selected from the following (a) to (j) is added to the above-mentioned solution in order to prevent precipitation of the eluted tin. The agents may be used alone or in an appropriate mixture.

(A) An aliphatic dicarboxylic acid having an alkyl group having 0 to 3 carbon atoms.

(B) An aliphatic hydroxymonocarboxylic acid having an alkyl group having 1 to 2 carbon atoms.

(C) An aliphatic hydroxypolycarboxylic acid having an alkyl group having 1 to 3 carbon atoms.

(D) Monosaccharides, polyhydroxycarboxylic acids having a part thereof oxidized, and cyclic ester compounds thereof.

(E) Aliphatic mono- or di-amino, mono- or di-carboxylic acid having an alkyl group having 1 to 4 carbon atoms.

(F) Aliphatic monomercaptomonocarboxylic acid having 2 to 3 carbon atoms in the alkyl group, aliphatic monomercaptodicarboxylic acid and aliphatic monomercaptomonoaminomonocarboxylic acid.

(G) Aliphatic monosulfomonocarboxylic acid and aliphatic monosulfodicarboxylic acid having an alkyl group having 2 to 3 carbon atoms.

(H) The following aminecarboxylic acids: ethylenediaminetetraacetic acid, iminodiacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, ethylenedioxybis (ethylamine) -N, N, N ', N'- Tetraacetic acid, glycol ethylenediaminetetraacetic acid, N-hydroxyethylethylenediaminetetraacetic acid.

(I) Condensed phosphoric acid.

(J) A hydroxyalkane bisphosphonic acid in which the alkane has 1 to 3 carbon atoms.

Preferred examples of the complexing agents (a) to (j) for keeping the tin ions eluted by substitution stable in the bath include the following.

Examples of the aliphatic dicarboxylic acid (a) include oxalic acid, malonic acid and succinic acid.

Examples of the aliphatic hydroxymonocarboxylic acid (b) include glycolic acid and the like.

Examples of the aliphatic hydroxypolycarboxylic acid (c) include tartaric acid and citric acid.

Examples of (d) monosaccharides, polyhydroxycarboxylic acids partially oxidized and cyclic ester compounds thereof include ascorbic acid, gluconic acid, glucoheptonic acid, and δ-gluconolactone.

(E) As the aliphatic aminocarboxylic acid,
Glycine and the like can be mentioned.

Examples of the (f) aliphatic mercaptocarboxylic acid include mercaptosuccinic acid.

Examples of (g) aliphatic sulfocarboxylic acid include sulfosuccinic acid.

Examples of the (h) aminocarboxylic acid include ethylenediaminetetraacetic acid, iminodiacetic acid and nitrilotriacetic acid.

(I) As the condensed phosphoric acid, pyrophosphoric acid,
Tripolyphosphoric acid etc. are mentioned.

Examples of the hydroxyalkane bisphosphonic acid (j) include 1-hydroxyethane-1,1-bisphosphonic acid.

The amount of those used is appropriately selected depending on the type of complexing agent and the concentration and pH of tin eluted in the plating bath,
The upper and lower limits are not particularly limited, but as the ratio of the complexing agent to tin decreases, precipitates tend to form,
Since the bath becomes unstable, it is necessary to have a number of moles that is approximately equal to that of tin. When the concentration of the complexing agent is extremely high, phenomena such as an increase in the viscosity of the bath appear. Fifty
It should be kept to about twice the molar amount. Therefore, the amount of the silver complexing agent used is 1 to 50 times, and preferably 2 to 30 times, the molar amount of tin ion.

Further, in the present invention, in order to suppress substitutional precipitation of silver and obtain a smoother and denser substituted silver film,
Further, a surfactant selected from the following general formulas (1) to (13) can be used alone or in admixture as a silver substitution inhibitor in the plating bath.

(1) General formula

[Chemical 44] [Here, R represents an alkyl group (C ₁ -C ₂₅ ), and A represents oxygen or a single bond. M represents hydrogen or an alkali metal. ] The naphthalene sulfonic acid type surfactant represented by these.

[0081]

(3) General formula

[Chemical 21] [Where A and B are —CH ₂ —CH ₂ —O— or —CH
_{2 -C (CH 3) H-} O- and represent, their existing position is not limited, m and n represent an integer of 0 to 40. However,
The sum of m and n is in the range 1-40. R represents a sorbitan esterified with fatty acids having a carbon number of 1-25.
D represents -O- or -COO-. ] Polyoxyalkylene sorbitan ether (or ester) represented by
System surfactant.

[0083]

(5) General formula

[Chemical 48] [Where A and B are —CH ₂ —CH ₂ —O— or —C
H ₂ —C (CH ₃ ) H—O— is represented, and the position where they are present is not limited, and m and n represent an integer of 0-40. However, the sum of m and n is in the range of 1 to 40. R represents hydrogen or an alkyl group (C ₁ ~C _25). ] The polyoxyalkylene naphthyl (or alkyl naphthyl) ether type surfactant represented by these.

(6) General formula

[Chemical 49] [Where A and B are —CH ₂ —CH ₂ —O— or —C
H ₂ —C (CH ₃ ) H—O— is represented, and the position where they are present is not limited, and m and n represent an integer of 0-40. However, the sum of m and n is in the range of 1 to 40. Ra,
Rb and Rc are each independently hydrogen, a phenyl group, an alkyl group (C _{1 to} C ₄ ), or —CH (CH ₃ ) —φ (φ
Is a phenyl group. ) Is represented. Provided that at least one is assumed to be a phenyl group or a -CH (CH ₃₎ -φ. ] A polyoxyalkylene styrenated phenyl ether type surfactant represented by the following.

(7) General formula

[Chemical 50] [Where A and B are —CH ₂ —CH ₂ —O— or —C
H ₂ —C (CH ₃ ) H—O— is represented, and their positions are not limited. R _c1 and R _c2 each independently represent hydrogen, a phenyl group or an alkyl group (C _{1 to} C ₄ ),
Rd and Re each independently represent hydrogen or —CH ₃ , and m1, m2, n1 and n2 are each independently 0 to 40.
Represents the integer. However, the sum of m1 and n1, and further m2 and n2 is within the range of 1 to 40. ] The polyoxyalkylene styrenated phenyl ether represented by these, and the surface active agent which added the polyoxyalkylene chain to the phenyl group.

(8) General formula

[Chemical 51] [Here, Ra and Rb are hydrogen or an alkyl group (C _1-
C ₂₅ ) and may be the same or different. A and B are-
CH ₂ -CH ₂ -O- or -CH ₂ -C (CH ₃₎ H-
Represents O-, and their existence position is not limited. m1,
m2, n1 and n2 each independently represent an integer of 0-40. However, the sum of m1 and n1, and further m2 and n2 is within the range of 1 to 40. M represents hydrogen or an alkali metal. ] The phosphate ester type surfactant represented by these.

(9) General formula

[Chemical formula 22] [Wherein, R represents an A sill group (C ₁ ~C _30), A and B are -CH ₂ -CH ₂ -O- or -CH ₂ -C (CH ₃₎ H
It represents —O—, and the position where they are present is not limited. m
1, m2, n1 and n2 each independently represent an integer of 0 to 6. However, the sum of m1 and n1, and the sum of m2 and n2 is within the range of 1 to 6. -CH ₂ -CH (CH ₃₎ -
O in molar number of addition is never greater than mole number of added -CH ₂ -CH ₂ -O. ] Polyoxyalkylene
Mid -surfactant.

(10) General formula

[Chemical 53] [Where A and B are —CH ₂ —CH ₂ —O— or —C
H ₂ —C (CH ₃ ) H—O— is represented, and their positions are not limited. m1, m2, m3, m4, n1, n
2, n3 and n4 are integers, and m1 + m2 + m3 + m4 =
5 to 70, n1 + n2 + n3 + n4 = 5 to 70.
m1, m2, n1, and n2 each independently represent an integer of 0 to 6. However, the sum of m1 and n1, and the sum of m2 and n2 is within the range of 1 to 6. x represents an integer of 2 or 3. R represents an alkyl group (C ₁ ~C ₃₀₎ or alkenyl group (C ₁ ~C _30). ] An alkylene oxide adduct-based surfactant of alkylenediamine represented by the following.

(11) General formula

[Chemical 54] [Here, Ra represents an alkyl group (C _{1 to} C ₂₀ ), R
b is (CH ₂ ) _m OH or (CH ₂ ) _m OCH ₂ COO
^- represents, Rc is an alkyl group _{(C 1 ~C 4), (} CH
₂ ) _n COO ⁻ , (CH ₂ ) _n SO ⁻ , CH (OH) C
H ₂ SO ₃ ⁻ , m and n each represent an integer of 1 to 4. M
Represents an alkali metal, and X represents a halogen, a hydroxyl group, or an alkanesulfonic acid group (C _{1 to} C ₅ ). When Rc is an alkyl group, M is absent. When Rc is other than an alkyl group, M may or may not be present, and when M is absent, X is also absent. ] Alkyl imidazolinium betaine-type surfactant represented by these.

(12) General formula

[Chemical 55] [Here, Ra represents hydrogen or a methyl group, or may have no bond. Rb represents hydrogen or a methyl group or an ethyl group, and one hydrogen atom of the alkyl group may be bonded to an acyloxy group through an ether bond. Rc represents an alkyl group (C ₅ ~C _20). The carboxyl group may be ionically bonded to hydrogen or an alkali metal. m is 1
Is an integer of 4 and n is an integer of 0 to 4. ] An alkyl (or amido) betaine-based surfactant represented by:

(13) General formula

[Chemical 56] [Where X is halogen, hydroxyl group or alkane sulfone
Acid group (C₁ ~ C_Five ), Ra is an alkyl group (C₁ 
~ C₂₀), And Rb and Rc are alkyl groups (C ₁ ~ C
_Four ) Or an alkoxyl group (C₁ ~ C_Ten), And Rd
Is an alkyl group (C₁ ~ C_Ten), Benzyl group or fatty acid
(CH₂ )_n COOH, where n is 1-18
Represents an integer. Re is an alkyl group (C₈ ~ C₂₀),
Rf is hydrogen or an alkyl group (C₁ ~ C_Four ) Represents. ]so
Ammonium or pyridinium quaternary salt-based surface active represented
Sex agent.

Further, specific examples of the suitable ones, which are easily available as a commercial product, are as follows.

Examples of the compound represented by the above formula (1) include Perex NB-L and DEMOL N (manufactured by Kao Corporation).

[0095]

As those represented by the above formula (3), Braunon EL-1303, Braunon EL-1509, Braunon CH-310 (manufactured by Aoki Yushi Kogyo Co., Ltd.), Newcol 1110 (manufactured by Nippon Emulsifier Co., Ltd.) Manufactured by Nikkol BL, Nikkor MYL-10 (manufactured by Nikko Chemicals Co., Ltd.), Neugen ET-170 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and the like.

[0097]

As those represented by the above formula (5), Braunon BN-18 (manufactured by Aoki Yushi Kogyo Co., Ltd.), Adekatol PC-10 (manufactured by Asahi Denka Co., Ltd.), Neugen EN-10 ( Daiichi Kogyo Seiyaku Co., Ltd.) and the like.

Examples of the compound represented by the above formula (6) include Newcol 2607 (manufactured by Nippon Emulsifier Co., Ltd.) and Blaunon DSP-9 (manufactured by Aoki Yushi-Seiyaku Co., Ltd.).

Examples of the compound represented by the above formula (7) include Liponox NC-100 (Lion).

As those represented by the above formula (8), ADEKA COL PS-440E and ADEKA COL CS-141
E, ADEKA COL TS-230E (manufactured by Asahi Denka Co., Ltd.) and the like.

As those represented by the above formula (9), Nymeen L207, Nymeen T2-210, Nymeen S-215 (manufactured by NOF Corporation), Newcol 42
0 (manufactured by Nippon Emulsifier Co., Ltd.), Braunon O-205
(Aoki Yushi Kogyo Co., Ltd.) and the like.

As those represented by the above formula (10), there are Tetronic TR-701 and Tetronic TR-702.
(Manufactured by Asahi Denka Kogyo Co., Ltd.) and the like.

As those represented by the above formula (11), softazoline CH, softazoline NS (manufactured by Kawaken Fine Chemicals Co., Ltd.), Nissan Anon GLM-R (manufactured by NOF Corporation), Levon 101-H (Manufactured by Sanyo Chemical Industry Co., Ltd.), Nikkor AM-103EX (manufactured by Nippon Emulsifier Co., Ltd.) and the like. Examples of the compound represented by the formula (12) include acetamine 24 (manufactured by Kao Corporation).

Examples of those represented by the above formula (13) include Nikkor CA2150, Nikkor CA101 (manufactured by Nikko Chemicals Co., Ltd.), and Texnor R-5 (manufactured by Nippon Emulsifier Co., Ltd.).

The concentration of these surfactants in the plating bath is 0.01 to 50 g / l, preferably 0.01 to 30.
g / l is used. Insufficient usage suppresses substitutional precipitation of silver, and the above-mentioned effect of obtaining a smoother and denser substitutional silver film cannot be expected.Excessive addition suppresses substitutional precipitation excessively and the deposition rate decreases extremely. And may have the adverse effect of not causing precipitation.

The pH range of the displacement silver plating bath of the present invention is strongly acidic to pH 13, preferably strongly acidic to 11.
When used in the neutral range, a pH buffering agent can be added to reduce pH fluctuation of the bath.

Known pH buffers can be used,
For example, sodium, potassium and ammonium salts of phosphoric acid, acetic acid, boric acid and tartaric acid, respectively, and in the case of polybasic acid, an acid salt containing hydrogen ion and the like can be used alone or in an appropriate mixture. The amount of pH buffer used is 5
About 50 g / l is suitable, preferably 10-20 g
/ L is added.

The substitution silver plating bath on tin used in the present invention is often used in a tin plating bath or a tin alloy plating bath in order to suppress natural oxidation of divalent tin ions accumulated by displacement elution in the liquid. Antioxidants can be added as described.

As the antioxidant, known ones can be used,
For example, resorcinol, pyrocatechol, hydroquinone, phlorogricinol, pyrogallol, hydrazine, ascorbic acid and the like can be used alone or in an appropriate mixture. The amount of the antioxidant used is appropriately about 0.05 to 50 g / l, and preferably 0.1 to 10 g / l is added.

Further, in the present invention, as the undercoating of the tin-silver substitution multi-layer plating is carried out so that the undercoating is utilized before the tinning or the tin-lead plating is applied to the electric / electronic circuit parts. Copper or nickel and their alloys can be plated as an undercoat by plating and / or electroless plating.

The concentration of each component of the plating bath of the present invention can be arbitrarily selected within the above range corresponding to barrel plating, rack plating, continuous plating and the like.

[0113]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples, and the composition of the displacement plating bath and plating conditions are It can be arbitrarily changed as appropriate.

A buff-polished copper plate was used as a substrate.
After cutting to 0.3 × 25 × 25 mm, benzine degreasing, electrolytic degreasing, and water washing were performed as a pretreatment according to a standard method, and then tin plating was applied as a base. A sulfuric acid bath or a methanesulfonic acid bath was used for tin plating to obtain a bright to semi-bright ² to 20 μ electrotin plating film at 2 A / dm ² .

When nickel plating is applied to the lower layer of the tin plating film, an ordinary matte electroplating bath is used, and when an electroless film is applied, an electroless electrolysis method using an ordinary hypophosphite as a reducing agent. A nickel-phosphorus alloy plating bath was used.

After washing the obtained tin-plated film with water, displacement silver plating was performed according to the plating bath and plating conditions described in the following Comparative Examples and / or Examples.

A solderability test was carried out by the meniscograph method, and the obtained film was evaluated from the zero cross time and the appearance state after the solderability test. The measurement conditions of the meniscograph method are tin-silver solder (tin 96.5% -silver 3.
5%), rosin flux, 250 ° C., immersion time 5 seconds.

Comparative Example 1 A copper plate sample was pretreated as described above and a solderability test was performed immediately after drying. Solderability was not good.

Comparative Example 2 A 20 μm semi-bright tin plating was applied from the following plating bath, a heat treatment was carried out at 150 ° C. for 16 hours in the atmosphere, and then a solderability test was conducted. Stannous sulfate (as tin) 30 g / l Sulfuric acid 50 g / l Polyethylene laurylamine 10 g / l 2-Mercaptobenzimidazole 0.05 g / l Cathode current density 2 A / dm ² Better than Comparative Example 1 Although it showed solderability, the performance was not satisfactory.

Comparative Example 3 A 2 μm bright tin plating was applied from the following plating bath, a heat treatment was carried out at 150 ° C. for 16 hours in the atmosphere, and then a solderability test was conducted. Tin methanesulfonate (as tin) 20 g / l Methanesulfonic acid 100 g / l Polyethylene glycol nonyl 10 g / l Phenyl ether 37% Formaldehyde 10 ml / l Benzaldehyde 0.08 g / l Cathode current density 2 A / dm ² The solderability was better than that of Comparative Example 1, but the performance was not satisfactory.

Comparative Example 4 After tin plating was performed in the same manner as in Comparative Example 2, the following bath 3 was used.
After performing displacement silver plating for 0 minutes, 150 ℃ -16 in the atmosphere
After heat treatment for a time, a solderability test was conducted. Silver cyanide (as silver) 6.5 g / l Sodium cyanide 9.5 g / l pH Strong alkali temperature 28 ° C. The obtained tin-silver two-layer film was obtained from the tin-only films of Comparative Examples 2 and 3. Also showed good solderability.

[0122]

[0123]

[0124]

Example 1 After tin-plating in the same manner as in Comparative Example 2, one of the following baths was used.
After performing displacement silver plating for 0 minutes, 150 ℃ -16 in the atmosphere
After heat treatment for a time, a solderability test was conducted.

Example 2 After tin plating was performed in the same manner as in Comparative Example 2, the following bath 1 was used.
After performing displacement silver plating for 0 minutes, 150 ℃ -16 in the atmosphere
After heat treatment for a time, a solderability test was conducted.

Example 3 After tin-plating in the same manner as in Comparative Example 2, the following bath 1 was used.
After performing displacement silver plating for 0 minutes, 150 ℃ -16 in the atmosphere
After heat treatment for a time, a solderability test was conducted.

Example 4 After tin plating was conducted in the same manner as in Comparative Example 3, the following bath 5 was used.
After performing displacement silver plating for one minute and heat-treating at 150 ° C. for 16 hours in the atmosphere, a solderability test was performed.

Example 5 After tin plating was conducted in the same manner as in Comparative Example 3, the following bath 3 was used.
After performing displacement silver plating for 0 minutes, 150 ℃ -16 in the atmosphere
After heat treatment for a time, a solderability test was conducted.

Example 6 After tin plating was performed in the same manner as in Comparative Example 3, the following bath 3 was used.
After performing displacement silver plating for 0 minutes, 150 ℃ -16 in the atmosphere
After heat treatment for a time, a solderability test was conducted.

Example 7 After tin plating was conducted in the same manner as in Comparative Example 2, the following bath 1 was used.
After performing displacement silver plating for one minute and heat-treating at 150 ° C. for 16 hours in the atmosphere, a solderability test was performed.

Example 8 After tin plating was carried out in the same manner as in Comparative Example 2, the following bath 2 was used.
After performing displacement silver plating for 0 minutes, 150 ℃ -16 in the atmosphere
After heat treatment for a time, a solderability test was conducted.

Example 9 After tin plating was performed in the same manner as in Comparative Example 2, the following bath 2 was used.
After performing displacement silver plating for 0 minutes, 150 ℃ -16 in the atmosphere
After heat treatment for a time, a solderability test was conducted.

Example 10 The same procedure as in Comparative Example 3 was followed by tin plating of 2 μm, and then the displacement silver plating for 2 minutes from the bath of Example 4 was repeated 5 times to obtain a tin-silver multilayer film. After forming, a heat treatment was performed at 150 ° C. for 16 hours in the atmosphere, and then a solderability test was performed.

The tin-silver bilayer coating and the tin-silver multilayer coating obtained in Examples 1 to 10 using the non-cyan bath were all better than the tin-only coatings of Comparative Examples 2 and 3, and It exhibited solderability equivalent to that of the tin-silver bilayer coating obtained by using the cyan bath of No. 4. The results of the solderability of the plated coatings in the above Comparative Examples and Examples are summarized in Table 1.

The solderability of the multi-layer coatings using the substitutional silver coating on tin obtained in Examples 1 to 10 is superior to the copper plate of the comparative example and the tin single coating in the aging characteristics. It was

[0137]

[Table 1]

[0138]

INDUSTRIAL APPLICABILITY The non-cyan silver displacement plating bath on a tin film according to the present invention has a solderability superior to that of a tin alone film, in particular, its time-dependent characteristics, and has characteristics comparable to a cyan bath.
By the invention of this bath, it is possible to obtain a solderable film when using tin-silver solder instead of tin-lead solder, which affects health and environment, without using a cyan bath. Therefore, the conversion from tin-lead solder to tin-silver solder can be facilitated.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masashi Masaki 21-8 Minami Futami, Futami-cho, Akashi-shi, Hyogo Daiwa Kasei Research Institute Ltd. (72) Inventor, Kazuhiro Aoki 5-26 Nishiyanagihara-cho, Hyogo-ku, Kobe-shi, Hyogo Ishihara Pharmaceutical Co., Ltd. (72) Inventor Hidemi Nabune 5-38-34, Makamicho, Takatsuki-shi, Osaka (56) Reference JP-A-8-232072 (JP, A) JP-A-9-302476 (JP, A) JP-A-60-100679 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 18 / 16-18 / 54

Claims (2)

(57) [Claims] 1. A monovalent silver ion of 0.01 to 50 g / l.
And (A) to (J) below for stabilizing the silver ions in a bath to obtain a smooth and dense substitutional deposition film of silver.
One or two or more of the silver complexing agents and the tin eluted by substitution
From the following (a) to (j) to prevent precipitation
One or more selected tin complexing agents and
Silver placement selected from (1), (3), (5) to (13)
A non-cyan substitutional silver plating bath for depositing a substitutional silver film on tin or a tin alloy, characterized by containing one or more substitutional precipitation inhibitors : (A) the following inorganic acid Ions: nitrate ion, nitrite ion, sulfate ion, sulfite ion, bisulfite ion, metabisulfite ion, chlorine ion, chlorate ion, perchlorate ion, bromine ion, bromate ion, iodine ion, iodate ion, Borofluoric acid ion, silicofluoric acid ion, sulfamate ion, thiosulfate ion, thiocyanate ion, (B) ammonium ion, (C) acetate ion, (D) the following general formula (i), (ii) or (iii) Sulfonic acid ion represented by: (i) General formula: [Here, R represents a C _{1 to} C ₁₂ alkyl group or a C _{2 to} C ₃ alkenyl group, and the hydrogen of the R is in the range of 0 to 3,
It may be substituted with a hydroxyl group, an alkyl group, an aryl group, an alkylaryl group, a carboxyl group or a sulfonic acid group, and may be at any position of the R. ] Aliphatic sulfonic acid represented by: (ii) General formula: [Wherein, R represents an alkyl group of C ₁ -C _3. X represents chlorine and / or fluorine halogen, which may be present at any position of the R, and the substitution number n1 of the halogen substituted with the hydrogen of the R is from 1 to all the hydrogens coordinated to the R. Saturated and substituted ones are shown, and the number of substituted halogen species is one or two. The hydroxyl group may be located at any position of the R, and the substitution number n2 of the hydroxyl group substituted with hydrogen of the R is 0 or 1. Y represents a sulfonic acid group, which may be present at any position of the R, and the substitution number n3 of the sulfonic acid group represented by Y is in the range of 0 to 2. ] A halogenated alkane sulfonic acid or halogenated alkanol sulfonic acid represented by the following formula: (iii) General formula [Where X represents a hydroxyl group, an alkyl group, an aryl group, an alkylaryl group, an aldehyde group, a carboxyl group, a nitro group, a mercapto group, a sulfonic acid group or an amino group, or two Xs together with a benzene ring Can form a naphthalene ring, and the substitution number n of the group is an integer of 0 to 3. ] An aromatic sulfonic acid represented by the formula (E): [Here, X represents oxygen or sulfur, and Ra and Rb each independently represent hydrogen, an amino group, or C _{1 to} C ₅ alkyl. Rc and Rd each independently represent hydrogen or C ₁ -C ₅ alkyl, alkenyl or phenyl, and the hydrogen of the alkyl, alkenyl and / or phenyl may be substituted with a hydroxyl group or an amino group, monomethyl or dimethylamino group. , Rc and Rd may combine to form a ring. ] Or urea or thiourea or thioacetamide or a derivative thereof represented by the following formula (F): [However, Ra, Rb, Rc, Rd is hydrogen, alkyl (C ₁ ~C ₅₎ groups, the hydrogen of the alkyl group may be substituted with a hydroxyl group. ] A hydantoin compound represented by the following formula (G): [However, Ra, Rb, Rc, and Rd each independently represent hydrogen or a C _{1 to} C ₅ alkyl group or alkoxy group. ] Succinimide (succinimide)
Or maleic imide and derivatives thereof, (H) general formula: [However, Ra, Rb, and Rc each independently represent hydrogen, a hydroxyl group, or C _{1 to} C ₅ alkyl, and the hydrogen of the alkyl group may be substituted with a hydroxyl group, an amino group, or chlorine. The groups may combine with each other to form a ring. ] The amine shown by these and its salt, (I) General formula [Here, R represents an alkylene group (C _{1 to} C ₅ ), and hydrogen of the alkylene group may be substituted with an amino group, or may be bonded to an acetyl group via the amino group. ] Or a thiocarboxylic acid or thiosulfonic acid represented by the formula (J). [Here, X represents oxygen, nitrogen or sulfur, and Y represents carbon or nitrogen. Z is hydrogen when X is nitrogen and is absent when oxygen or sulfur. A represents hydrogen or thiol and is absent when Y is nitrogen. Hydrogen on the benzene ring may be substituted with a methoxy group or ethoxy. Benzotriazole represented by, benzothiazole, benzimidazole or benzoxazole and induction of their carbon number of (a) aliphatic dicarboxylic acids of carbon atoms in the alkyl group is 0 to 3, (b) an alkyl group 1 ~ 2 aliphatic hydroxymonocarboxylic acid, (c) aliphatic hydroxypolycarboxylic acid having 1 to 3 carbon atoms in the alkyl group (d) monosaccharide and partially oxidized polyhydroxycarboxylic acid, and cyclics thereof Ester compound, (e) Aliphatic mono- or di-amino, mono- or di-carboxylic acid having 1 to 4 carbon atoms in the alkyl group, (f) Aliphatic monomercapto having 2 to 3 carbon atoms in the alkyl group Monocarboxylic acid and aliphatic monomercaptodicarboxylic acid and aliphatic monomercaptomonoaminomonocarboxylic acid, and (g) the carbon number of the alkyl group is 2 to 3 Aliphatic monosulfomonocarboxylic acid and aliphatic monosulfodicarboxylic acid, (h) the following aminecarboxylic acids: ethylenediaminetetraacetic acid, iminodiacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, ethylenedioxybis (ethylamine ) -N, N, N ', N'-tetraacetic acid, glycol ethylenediaminetetraacetic acid, N-hydroxyethylethylenediaminetetraacetic acid, (i) condensed phosphoric acid, (j) hydroxyalkane bisphosphone having 1 to 3 carbon atoms of alkane Acid, (1) general formula: [Here, R represents an alkyl group (C ₁ -C ₂₅ ), and A represents oxygen or a single bond. M represents hydrogen or an alkali metal. ] A naphthalene sulfonic acid-based surfactant represented by the formula (3) : [Where A and B are —CH ₂ —CH ₂ —O— or —CH
_{2 -C (CH 3) H-} O- and represent, their existing position is not limited, m and n represent an integer of 0 to 40. However,
The sum of m and n is in the range 1-40. R represents a sorbitan esterified with fatty acids having a carbon number of 1-25.
D represents -O- or -COO-. ] A polyoxyalkylene sorbitan ether (or ester) -based surfactant represented by: (5) General formula: [Where A and B are —CH ₂ —CH ₂ —O— or —CH
_{2 -C (CH 3) H-} O- and represent, their existing position is not limited, m and n represent an integer of 0 to 40. However,
The sum of m and n is in the range 1-40. R represents hydrogen or an alkyl group (C ₁ ~C _25). ] A polyoxyalkylene naphthyl (or alkyl naphthyl) ether-based surfactant represented by the formula (6): [Where A and B are —CH ₂ —CH ₂ —O— or —CH
_{2 -C (CH 3) H-} O- and represent, their existing position is not limited, m and n represent an integer of 0 to 40. However,
The sum of m and n is in the range 1-40. Ra, R
b and Rc each independently represent hydrogen, a phenyl group, an alkyl group (C _{1 to} C ₄ ), or —CH (CH ₃ ) -φ (φ is a phenyl group). Provided that at least one is assumed to be a phenyl group or a -CH (CH ₃₎ -φ. ] A polyoxyalkylene styrenated phenyl ether-based surfactant represented by the formula (7): [Where A and B are —CH ₂ —CH ₂ —O— or —CH
_{2 -C (CH 3) H-} O- and represent, their existing position is not limited. R _c1 and R _c2 each independently represent hydrogen, a phenyl group or an alkyl group (C _{1 to} C ₄ ), and R _d and R _e
Each independently represent hydrogen or —CH ₃ , m1,
m2, n1 and n2 each independently represent an integer of 0-40. However, the sum of m1 and n1, and further m2 and n2 is within the range of 1 to 40. ] A polyoxyalkylene styrenated phenyl ether represented by the following formula, wherein a polyoxyalkylene chain is further added to the phenyl group, (8) General formula [Here, Ra and Rb are hydrogen or an alkyl group (C _1-
C ₂₅ ) and may be the same or different. A and B are-
CH ₂ -CH ₂ -O- or _{-CH 2 -C (CH 3) H} -O-
And their location is not limited. m1, m
2, n1 and n2 each independently represent an integer of 0-40. However, the sum of m1 and n1, and further m2 and n2 is within the range of 1 to 40. M represents hydrogen or an alkali metal. ] A phosphoric acid ester-based surfactant represented by the formula (9): [Wherein, R represents an A sill group (C ₁ ~C _30), A and B are -CH ₂ -CH ₂ -O- or -CH ₂ -C (CH ₃₎ H
It represents —O—, and the position where they are present is not limited. m
1, m2, n1 and n2 each independently represent an integer of 0 to 6. However, the sum of m1 and n1, and the sum of m2 and n2 is within the range of 1 to 6. -CH ₂ -CH (CH ₃₎ -
O in molar number of addition is never greater than mole number of added -CH ₂ -CH ₂ -O. ] Polyoxyalkylene
Mido-based surfactant, (10) general formula: [Where A and B are —CH ₂ —CH ₂ —O— or —CH
_{2 -C (CH 3) H-} O- and represent, their existing position is not limited. m1, m2, m3, m4, n1, n2, n
3 and n4 are integers, and m1 + m2 + m3 + m4 = 5 to 7
0, n1 + n2 + n3 + n4 = 5 to 70. m1,
m2, n1 and n2 each independently represent an integer of 0 to 6. However, the sum of m1 and n1, and the sum of m2 and n2 is within the range of 1 to 6. x represents an integer of 2 or 3.
R is an alkyl group (C _{1 to} C ₃₀ ) or an alkenyl group (C ₁ to C ₃₀ ).
_C30 ). ] An alkylene oxide adduct-based surfactant of alkylenediamine represented by: (11) General formula: [Here, Ra represents an alkyl group (C _{1 to} C ₂₀ ), R
b is (CH _{2) m} OH or _{(CH 2) m OCH 2 COO} - represents, Rc is an alkyl group _{(C 1 ~C 4), (} CH 2) n COO
^{_{-, (CH 2) n SO}} 3 -, CH (OH) CH 2 SO 3 - represents, m and n represent an integer of 1 to 4. M represents an alkali metal, and X represents a halogen, a hydroxyl group or an alkanesulfonic acid group (C _{1 to} C ₅ ). When Rc is an alkyl group,
When M is absent and Rc is other than an alkyl group, M may or may not be present, and when M is absent, X is present.
Does not exist either. ] An alkyl imidazolinium betaine-based surfactant represented by the formula (12): [Here, Ra represents hydrogen or a methyl group, or may have no bond. Rb represents hydrogen or a methyl group or an ethyl group, and one hydrogen atom of the alkyl group may be bonded to an acyloxy group through an ether bond. Rc represents an alkyl group (C ₅ ~C _20). The carboxyl group may be ionically bonded to hydrogen or an alkali metal. m is 1
Is an integer of 4 and n is an integer of 0 to 4. ] An alkyl (or amido) betaine-based surfactant represented by: (13) a general formula: [Here, X represents a halogen, a hydroxyl group, or an alkanesulfonic acid group (C _{1 to} C ₅ ), and Ra represents an alkyl group (C ₁ to C ₅ ).
Represents _20), Rb and Rc represents an alkyl group (C ₁ ~C ₄₎ or an alkoxyl group (C ₁ ~C _10), Rd represents an alkyl group (C ₁ ~C _10), a benzyl group or a fatty acid (CH ₂ ) _N
Represents COOH, where n represents an integer of 1-18.
Re represents an alkyl group (C ₈ ~C _20), Rf represents a hydrogen or an alkyl group (C ₁ ~C _4). ] The ammonium or pyridinium quaternary salt type surfactant represented by these. 2. Further, a pH buffering agent for maintaining the pH of the bath and / or a tin antioxidant for preventing substitutional elution of tin to form tetravalent tin and to precipitate is included. The non-cyan-substituted silver plating bath according to claim 1, wherein