JP2001254194A - Tin, lead and tin-lead alloy plating bath - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the appearance and solderability of an electrodeposited film by incorporating a specified additive into tin, lead or tin-lead alloy plating bath. SOLUTION: This tin, lead and tin-lead alloy plating bath contains (A) a soluble metallic salt consisting of the one among a stannous salt, a lead salt and a mixture of the stannous salt and lead salt and (B) a straight-chain aliphatic hydrocarbon compound with an ethylene oxide, propylene oxide or hydropropylene oxide group existing in a single or repeating molecule adjacent to one or both sides of a basically mono- or disulfide coupling. Since the bath contains the specified straight-chain aliphatic hydrocarbonic compound, the uniformity, denseness, color tone or solder wettability are improved in the wide pH range from acidic to weakly alkaline region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating bath for tin, lead and a tin-lead alloy, which provides improved plating film uniformity and denseness and improved solder wettability.

[0002]

2. Description of the Related Art Tin, lead or tin-lead alloy plating has good solderability and corrosion resistance, or is used as a film for an etching resist, and is typically used for parts for the light electric industry and lead frames. Widely used in electronic industry components.

The present applicant has previously disclosed various techniques for improving a plating film by adding a specific additive to a tin, lead or tin-lead alloy plating bath. For example, JP
Japanese Patent No. 182,986 discloses an organic sulfonic acid bath containing a specific nonionic surfactant in which an ethylene oxide chain and a propylene oxide chain coexist to improve the plating film uniformly and densely in a wide current density range. Tin-
A lead alloy plating bath has been disclosed.

Japanese Patent Application Laid-Open No. 9-20732 discloses that
A tin and tin-lead alloy plating bath containing a novel arylalkyl-based quaternary ammonium compound to improve the gloss and solderability of a plating film has been disclosed.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to improve the properties of an electrodeposition film by adding a specific additive to a tin, lead or tin-lead alloy plating bath as in the prior art. Specifically, it is a technical object to improve the appearance of the film and the solder wettability.

[0006]

SUMMARY OF THE INVENTION The present inventors have found that in tin, lead or tin-lead alloy plating baths, a specific alkylene oxide group or hydroxy group is basically provided on either or both sides of a mono- or disulfide bond. When an alkylene oxide group contains a linear or aliphatic hydrocarbon compound in which a single or repeated molecule is present, a wide pH range from acidic to weakly alkaline is obtained.
In the region, it was found that the appearance of the plating film, the solder wettability and the like were improved. In addition, the inventors have found that the addition of a specific benzoazole-based compound in addition to the above-mentioned aliphatic hydrocarbon compound further improves the above-mentioned film properties, thereby completing the present invention.

That is, the present invention 1 comprises (A) a soluble metal salt comprising a stannous salt and a mixture of a lead salt, a stannous salt and a lead salt, and (B) a soluble metal salt represented by the following general formula (I) At least one of the linear aliphatic hydrocarbon compounds represented by the formula: H- (OA) a- (S) b-AB- (AO) cH (A) (in the above general formula (A) , AO is ethylene oxide, propylene oxide, hydroxypropylene oxide,
Provided that when a is 2 or more and AO is repeated, each AO in the repetition may be different from each other; A is ethylene, propylene, or hydroxypropylene, provided that
When A is hydroxypropylene, ethylene oxide and propylene oxide can be added to the hydroxyl group. Further, each of A in (OA) a and A and (AO) c may be different from each other; An integer, where a ≠
0, B = S, c ≠ 0, and a + c = 2
B is 1 or 2; B is 1 or 2; B is 1 or 2 when A is hydroxypropylene;
Is S or O when b = 1 and O when b = 2. ), A tin, lead and tin-lead alloy plating bath.

[0008] The present invention 2 is the above-mentioned invention 1, further comprising at least one benzoazole-based compound represented by the following general formula (b):

Embedded image (Wherein X is O, S, NH; R ₁ is SH, SR
(R is COOM, SO ₃ M (M is hydrogen, alkali metal,
Alkaline earth metals, ammonia, C ₁ -C ₆ alkyl which is not the or substituted substituted by amines)), S- allyl,
S-aryl; R ₂ , R ₃ , R ₄ and R ₅ may be the same or different, and each of H, SH, OH, OR (R is COO
H-substituted or unsubstituted C ₁ -C ₆ alkyl),
SR (R is C ₁ substituted or unsubstituted with COOH
-C ₆ alkyl), halogen, COOH, NH _2, NO _2,
NRR '(R, R' are each C ₁ -C ₆ alkyl, or taken together form a ring), SO ₃ M (M is hydrogen, an alkali metal, alkaline earth metal, ammonia, amine). ), A tin, lead and tin-lead alloy plating bath.

[0009] The present invention 3 is an acidic tin, lead and tin-lead alloy plating bath according to the present invention 1 or 2, which contains an organic sulfonic acid.

[0010] The present invention 4 is the invention of the above-mentioned invention 1 or 2, which contains a complexing agent and has a pH of the plating bath of 1.0.
It is a tin, lead and tin-lead alloy plating bath characterized by being 5 to 9.0.

[0011] The present invention 5 is characterized in that, in the above-mentioned present invention 4, tin, lead and tin-containing at least one of an alkali metal salt, an alkaline earth metal salt, an ammonium salt and an amine salt of an organic sulfonic acid. This is a lead alloy plating bath.

The present invention 6 is the invention according to any of the above inventions 1 to 5, further comprising a surfactant, a brightener, a semi-brightener, a smoothing agent, an auxiliary complexing agent, a pH buffer, a conductive salt, and a preservative. A tin, lead and tin-lead alloy plating bath containing at least one additive selected from the group consisting of antioxidants.

According to a seventh aspect of the present invention, in the sixth aspect, the surfactant is a nonionic surfactant.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The linear aliphatic hydrocarbon compound represented by the above general formula (a) basically has an ethylene oxide group, a propylene oxide group on both sides or one side of a mono- or disulfide bond. Or a compound in which a hydroxypropylene oxide group is present singly or repeatedly in the molecule. As described above, AO of the above formula (A) is ethylene oxide (C ₂ H ₄ O), propylene oxide (C ₃ H ₆ O),
Hydroxypropylene oxide (CH ₂ CH (OH) CH ₂
O). Thus, A is ethylene, propylene, hydroxypropylene. However, when A is hydroxypropylene, ethylene oxide and propylene oxide may be added to the hydroxyl group as shown in the formula (25) described below. Also, (OA) a and A in the above formula (A)
Each A in (AO) c may be the same or different from each other,
For example, each A may be common to ethylene, but (OA) a
In (A) is ethylene, A between (S) b and B is propylene, and A in (OA) c may be hydroxypropylene. In the above formula (a), a and c are integers, a does not take 0, and c does not take 0 when B is a sulfur atom. The sum of a and c is 2-200
It is. However, when A is hydroxypropylene,
The sum of a and c is 1 to 200. In addition, b in the above equation (a)
Is 1 or 2, and B is a sulfur atom or an oxygen atom. B is determined by the value of the integer b, and when b is 1, it is a sulfur atom or an oxygen atom, and when b is 2, it is an oxygen atom.

When the compound represented by the general formula (a) is described in detail, since the integer a is not 0, one end of the compound is-(OA) aH, and when B is a sulfur atom,
Since the integer c is not 0, the other end of the compound is -S-
(AO) cH. For this reason, the terminal of the compound always becomes an alkylene oxide group or a hydroxyalkylene oxide group, and the terminal does not become an SH group. Therefore, mercaptans are excluded from the compound of the present invention.
Incidentally, when B is an oxygen atom, the integer c can take 0, but in this case, the other end of the compound becomes OH and does not become an SH group.

The integer b is 1 or 2, and when b = 1, B is a sulfur or oxygen atom.
Is H- (OA) a-S-A-S- (AO) c-H or H-
(OA) a-S- (AO)-(AO) c-H is a compound in which a monosulfide bond is repeated singly or twice adjacent to the AO group. Further, when b = 2, B = oxygen atom, so that the general formula (A) is represented by H- (OA) a-S-S-S
-(AO)-(AO) c-H to be a compound in which a disulfide bond and an AO group are adjacent to each other.

Specific examples of the above linear aliphatic hydrocarbon compounds include the following compounds. _{(1) H- (OCH 2 CH} 2) 3 -S- (CH 2 CH 2 O) 3 bis represented by -H (triethylene glycol) thioether _{(2) H- (OCH 2 CH} 2) 6 -S _{- (CH 2 CH 2 O)} 6 bis represented by -H (hexaethylene glycol) thioethers _{(3) H- (OCH 2 CH} 2) 10 -S- (CH 2 CH 2 O) 10 -H
Bis (decaethylene glycol) thioether represented by the formula (4) H- (OCH ₂ CH ₂ ) ₁₂ -S- (CH ₂ CH ₂ O) ₁₂ -H
(5) H- (OCH ₂ CH ₂ ) ₁₅ -S- (CH ₂ CH ₂ O) ₁₅ -H
(6) H- (OCH ₂ CH ₂ ) ₂₀ -S- (CH ₂ CH ₂ O) ₂₀ -H
Bis (icosaethylene glycol) thioether represented by the formula (7) H- (OCH ₂ CH ₂ ) ₃₀ -S- (CH ₂ CH ₂ O) ₃₀ -H
(8) H- (OCH ₂ CH ₂ ) ₄₀ -S- (CH ₂ CH ₂ O) ₄₀ -H
Bis (tetracontaethylene glycol) thioether represented by the formula (9) H- (OCH ₂ CH ₂ ) ₅₀ -S- (CH ₂ CH ₂ O) ₅₀ -H
(10) H- (OCH ₂ CH ₂ ) ₅ -SS- (CH ₂ CH ₂ O) _5-
Bis (ω-hydroxypentaethoxy) disulfide represented by H (11) H- (OCH ₂ CH ₂ ) ₁₂ -SS- (CH ₂ CH ₂ O) ₁₂
Bis (ω-hydroxydodecaethoxy) disulfide represented by -H (12) H- (OCH ₂ CH ₂ ) ₂₀ -SS- (CH ₂ CH ₂ O) ₂₀
Bis (ω-hydroxyicosaethoxy) disulfide represented by -H (13) H- (OCH ₂ CH ₂ ) ₅₀ -SS- (CH ₂ CH ₂ O) ₅₀
Bis (ω-hydroxypentacontaethoxy) disulfide represented by -H (14) H- (OCH ₂ CH (OH) CH ₂ ) ₈ -S- (CH ₂ CH
(OH) CH ₂ O) ₈ bis represented by -H (oct glycerol) thioether _{(15) H- (OC 3 H} 6) 5 - (OC 2 H 4) 15 -S- (C 2 H 4 O)
_{15 - (C 3 H 6 O} ) 5 bis represented by -H (pentadecalactone glycol pentaethylene glycol) thioethers _{(16) H-OCH 2 CH} (OH) CH 2 - (OC 2 H 4) 10 -S −
_{(C 2 H 4 O) 10} -CH 2 CH (OH) bis represented by CH ₂ OH (decaethylene glycol mono glycerol) thioether _{(17) H- (OC 2 H} 4) 10 - (OC 3 H ₆ ) ₃ -S- (C ₃ H ₆ O) ₃
- (C ₂ H ₄ O) bis represented by ₁₀ -H (tripropylene glycol decamethylene glycol) thioethers _{(18) H- (OC 3 H} 6) 5 - (OC 2 H 4) 15 -S-S- (C ₂ H _{4
O) 15 - (C 3 H} 6 O) 5 bis represented by -H (.omega.-hydroxy penta propoxy pentadecanoyl ethoxy) disulfide _{(19) H-OCH 2 CH} (OH) CH 2 - (OC 2 H 4) ₁₀ -S-
_{S- (C 2 H 4 O)} 10 -CH 2 CH (OH) bis represented by CH ₂ OH (.omega.-hydroxy-mono-glycerophosphate carboxymethyl deca ethoxy) disulfide _{(20) H- (OC 2 H} 4) 20 -(OC ₃ H ₆ ) ₅ -SS- (C ₃ H _{6
O) 5 - (C 2 H} 4 O) bis represented by ₂₀ -H (.omega.-hydroxy equalize ethoxylated pentaerythritol propoxylate) disulfide _{(21) H- (OC 2 H} 4) 5 -S-CH 2 CH 2 - S- (C ₂ H
₄ O) S represented by ₅ -H, S'-bis (pentaethylene glycol) ethylene dithioether _{(22) H- (OC 2 H} 4) 15 -S-CH 2 CH 2 -S- (C 2 H _Four
O) ₁₅ S represented by -H, S'-bis (pentadecalactone ethylene glycol) ethylene dithioether _{(23) H- (OC 2 H} 4) 30 -S-CH 2 CH 2 CH 2 -S- (C
₂ H ₄ O) ₃₀ S represented by -H, S'-bis (triacontanyl ethylene glycol) propylene dithio ether _{(24) H- (OC 3 H} 6) 3 - (OC 2 H 4) 20 -S- CH ₂ CH ₂
S represented by —S— (C ₂ H ₄ O) ₂₀ — (C ₃ H ₆ O) ₃ —H,
S'-bis (tripropylene glycol icosaethylene glycol) ethylene dithioether

(25) S, S'-bis represented by the following formula (1)
(Decaethylene glycol) -2-decaoxyethylene propylene dithioether

Embedded image

(26) H- (OCH ₂ CH ₂ ) ₂ -S- (CH ₂ C
H ₂ O) bis represented by ₂ -H (diethylene glycol) thioether _{(27) HOCH 2 CH (OH} ) CH 2 -S-CH 2 CH (OH)
CH-bis (monoglycerol) represented by ₂ OH thioether _{(28) H- (OCH 2 CH} (OH) CH 2) 3 -S- (CH 2 CH
Bis (triglycerol) thioether represented by (OH) CH ₂ O) ₃ -H (29) H- (OCH ₂ CH ₂ ) ₄₁ -SS- (CH ₂ CH ₂ O) ₄₁
Bis (ω-hydroxyphentetracontaethoxy) disulfide represented by —H (30) H— (OC ₃ H ₆ ) ₅ — (OC ₂ H ₄ ) ₂₀ —SS— (C ₂ H _{4
O) 20 - (C 3 H} 6 O) 5 bis represented by -H (.omega.-hydroxy penta propoxycarbonyl alkoximinoalkyl Cosa ethoxy) disulfide _{(31) H- (OCH 2 CH} (OH) CH 2) 3 -S-S − (CH ₂
Bis (ω-hydroxytriglyceroxy) disulfide represented by CH (OH) CH ₂ O) ₃ —H (32) H- (OCH ₂ CH (OH) CH ₂ ) ₁₀ —SS— (CH ₂
Bis (ω-hydroxydecaglyceroxy) disulfide represented by CH (OH) CH ₂ O) ₁₀ —H (33) HOCH ₂ CH ₂ —S—CH ₂ CH ₂ —S—CH ₂ CH ₂
S represented by OH, S'-bis (monoethylene glycol) ethylene dithioether _{(34) H- (OC 2 H} 4) 10 -S-C 3 H 6 -S- (OC 2 H 4) 10
S represented by -H, S'-bis (decamethylene glycol) propylene dithio ether _{(35) H- (OCH 2 CH} 2) 5 -S-CH 2 CH (OH) CH 2
_{-S- (CH 2 CH 2 O)} 5 S represented by -H, S'-bis
(Pentaethylene glycol) -2-hydroxypropylene dithioether (36) H- (OC ₃ H ₆ ) ₂ -S-CH ₂ CH (OH) CH ₂ -S
_{- (C 3 H 6 O)} S represented by ₂ -H, S'-bis (dipropylene glycol) -2-hydroxypropylene dithioether _{(37) H- (OCH 2 CH} 2) 20 -S-CH 2 CH ₂ -S- (C
H ₂ CH ₂ O) ₂₀ S represented by -H, S'-bis (equalizing sub ethylene glycol) ethylene dithioether

Therefore, the above specific compound is represented by the general formula
Various examples in the case of expressing by applying (a) will be described below. For example, in the above general formula (A), AO = C ₂ H ₄ O
(Ethylene oxide), a = 3, b = 1, A = C ₂ H ₄ (ethylene), B = O, and c = 2, the linear aliphatic hydrocarbon compound of the present invention has the above formula (1) ) Represents bis (triethylene glycol) thioether. Similarly, AO = C ₂ H
₄ O (ethylene oxide), a = 15, b = 1, A = C ₂ H
₄ (ethylene), B = O, c = 14 represents bis (pentadecaethylene glycol) thioether of the above formula (5). AO = C ₂ H ₄ O (ethylene oxide), a = 12, b
= 2, A = C ₂ H ₄ (ethylene), B = O, and c = 11 represent bis (ω-hydroxydodecaethoxy) disulfide of the above formula (11). AO = CH ₂ CH (OH) CH ₂ O (hydroxypropylene oxide), a = 8, b = 1, A =
CH ₂ CH (OH) CH ₂ (hydroxypropylene), B =
When O and c = 7, it represents bis (octaglycerol) thioether of the above formula (14). When AO = hydroxypropylene oxide, a = 1, b = 1, A = hydroxypropylene, B = O, c = 0, it represents a bis (monoglycerol) thioether of the above formula (27). When AO = hydroxypropylene oxide, a = 3, b = 1, A = hydroxypropylene, B = O, c = 2, it represents a bis (triglycerol) thioether of the above formula (28). AO = ethylene oxide, a = 5, b = 1, A = ethylene, B = S, c =
In the case of 5, it represents S, S'-bis (pentaethylene glycol) ethylene dithioether of the above formula (21). AO = ethylene oxide, a = 30, b = 1, A = propylene, B
When = S and c = 30, it represents S, S'-bis (triacontaethylene glycol) propylene dithioether of the above formula (23). In this case, A in (OA) a and (AO) b is ethylene, A in the center is propylene, and each A
Is different. AO = ethylene oxide, a = 5, b = 1,
When A = hydroxypropylene, B = S and c = 5, S, S′-bis (pentaethylene glycol)-of the above formula (35)
Represents 2-hydroxypropylene dithioether. In this case, A in (OA) a and (AO) b is ethylene, A in the central position is hydroxypropylene, and each A is different. (OA) A at a = propylene oxide and ethylene oxide, a = 20, b = 2, A = ethylene, B =
When O and (OA) c, A = ethylene oxide and propylene oxide, and c = 19, it represents bis (ω-hydroxypentapropoxypentadecaethoxy) disulfide of the above formula (18). In this case, AO is repeated in a chain at a = 20 and c = 19, and each AO in the repetition is different from each other, and a chain block of ethylene oxide and a chain block of propylene oxide coexist. Also,
In the above formula (19), each AO in the repetition is different from each other, and a chain block of ethylene oxide and a chain block of hydroxypropylene oxide coexist. The above formula (2
In 5), as described above, A in the center is hydroxypropylene and an ethylene oxide chain is added to the hydroxyl group.

The above linear aliphatic hydrocarbon compound can be used alone or in combination. The total concentration of the aliphatic hydrocarbon compound in the plating bath is 0.1 to 50 g / L, preferably 1 to 30 g / L.
g / L.

The benzoazole-based compound to be used in combination with the above-mentioned linear aliphatic hydrocarbon compound has a general formula as described above.
(B). In the general formula (B), X is O, S, NH, and the substituent R ₁ is a sulfur-containing functional group such as SH or SR. Therefore, this benzoazole-based compound is a benzothiazole, benzimidazole, or benzoxazole having a specific sulfur-containing functional group at position 2 of the condensed heterocycle. Specific examples of the benzoazole-based compound include 2-mercaptobenzothiazole, 6-methoxy-2-mercaptobenzothiazole,
3- (2-benzothiazolylthio) -1-propanesulfonic acid and its salt, 2-methylmercaptobenzothiazole, 6-chloro-2-mercaptobenzothiazole, 2
-Benzothiazolethioacetic acid, 6-amino-2-mercaptobenzothiazole, 6-nitro-2-mercaptobenzothiazole, 2-mercaptobenzimidazole,
2-mercaptobenzoxazole, 6-methoxy-2
-Mercaptobenzimidazole, 2-methylmercaptobenzimidazole, 6-amino-2-mercaptobenzimidazole, 6-methoxy-2-mercaptobenzoxazole, 2-methylmercaptobenzoxazole and the like. Preferably, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole,
6-methoxy-2-mercaptobenzothiazole, 2-
Methyl mercaptobenzothiazole, 2-benzothiazolethioacetic acid and the like. The above-mentioned benzoazole compounds can be used alone or in combination, and the total concentration of the compounds in the plating bath is 0.001 to 20 g / L, preferably 0.005 to 20 g / L.
2 g / L.

The soluble metal salt used in the tin, lead or tin-lead alloy plating bath of the present invention basically refers to any organic or inorganic metal salt that produces a corresponding metal ion in water. Specific examples of the soluble stannous salt include methanesulfonic acid,
Starting with stannous salts of organic sulfonic acids such as ethanesulfonic acid, 2-propanolsulfonic acid, sulfosuccinic acid, p-phenolsulfonic acid, stannous borofluoride, stannous sulfate, stannous oxide, stannous chloride Tin and the like. Examples of the soluble lead salt include the above-mentioned lead salts of organic sulfonic acids, lead chloride, lead oxide, lead carbonate, lead acetate, lead borofluoride, lead oxalate, lead citrate, and the like. The above-mentioned soluble metal salt can be used alone or in combination, and its content in the plating bath is 0.5 to 300 g / L, preferably 10 to 120 g / L, in terms of metal.

The tin, lead or tin-lead alloy plating bath of the present invention is basically an organic acid bath, an inorganic acid bath or a bath based on a salt thereof. Carboxylic acids and the like, and inorganic acids include sulfuric acid, hydrochloric acid, borofluoric acid, hydrofluorosilicic acid, sulfamic acid, etc., but organic compounds are preferred in terms of the solubility of tin and lead and the ease of wastewater treatment. Sulfonic acid is preferred. Tin of the present invention,
A lead or tin-lead alloy plating bath can be applied regardless of an acid bath or a neutral bath.

In general, however, stannous ions are stable in an acidic condition. However, when the concentration of the stannous ions is near or above neutral, white precipitation may occur or the bath may be decomposed. From the viewpoint, the inclusion of a complexing agent is effective. Complexing agents include ethylenediamine, ethylenediaminetetraacetic acid
(EDTA), diethylenetriaminepentaacetic acid (DTPA),
Nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), iminodipropionic acid (IDP), hydroxyethylethylenediaminetriacetic acid (HEDTA), triethylenetetramine hexaacetic acid (TTHA), ethylenedioxybis (ethylamine) -N, N , N ', N'-tetraacetic acid, succinic acid, citric acid, tartaric acid, glycolic acid, glycine, mercaptosuccinic acid, gluconic acid, glucoheptonic acid, gluconolactone, glucoheptonolactone, nitrilotrimethylphosphonic acid, salts thereof, Or these derivatives can be used alone or in combination. The plating bath having a pH of about 1.5 to 9.0 including around neutral contains alkali metal salts, alkaline earth metal salts, ammonium salts, and amine salts of organic sulfonic acids such as aliphatic sulfonic acids and aromatic sulfonic acids. Bath is useful. Examples of the organic sulfone salt include sodium, potassium, magnesium, calcium, ammonium, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, triethylenepentamine, and pentaethylenetetramine. The above acids or salts thereof can be used alone or in combination, and the content thereof is 0.1 to 10 mol / L, preferably 0.5 to 5 mol / L. The content of the complexing agent is basically 0.05 to 5 mol / L, preferably 0.1 to 2 mol / L.
mol / L.

The above-mentioned organic sulfonic acid is alkanesulfonic acid, alkanolsulfonic acid, sulfosuccinic acid, aromatic sulfonic acid and the like.
Those represented by the chemical formula C _n H _{2n + 1} SO ₃ H (for example, n = 1 to 11) can be used, and specifically, methanesulfonic acid,
Examples thereof include ethanesulfonic acid, 1-propanesulfonic acid, 2-propanesulfonic acid, 1-butanesulfonic acid, 2-butanesulfonic acid, and pentanesulfonic acid.

[0027] Examples of the alkanol sulfonic acid, the formula _{C m H 2m + 1 -CH (} OH) -C p H 2p -SO 3 H ( e.g., m = 0
~ 6, p = 1 ~ 5), specifically, 2-hydroxyethane-1-sulfonic acid, 2-hydroxypropane-
1-sulfonic acid (2-propanolsulfonic acid), 2-hydroxybutane-1-sulfonic acid, 2-hydroxypentane-1-sulfonic acid, etc., as well as 1-hydroxypropane-2-sulfonic acid, 3-hydroxypropane 1-sulfonic acid, 4-hydroxybutane-1-sulfonic acid, 2
-Hydroxyhexane-1-sulfonic acid and the like.

The aromatic sulfonic acid is basically benzenesulfonic acid, alkylbenzenesulfonic acid, phenolsulfonic acid, naphthalenesulfonic acid, alkylnaphthalenesulfonic acid, naphtholsulfonic acid, and the like. Examples include acid, 2-naphthalenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, p-phenolsulfonic acid, cresolsulfonic acid, sulfosalicylic acid, nitrobenzenesulfonic acid, sulfobenzoic acid, and diphenylamine-4-sulfonic acid. Among the above organic sulfonic acids, methanesulfonic acid, ethanesulfonic acid, 2-propanolsulfonic acid, phenolsulfonic acid and the like are preferable.

On the other hand, the tin or tin-lead alloy plating bath of the present invention may contain, in addition to the above-mentioned components, a known surfactant depending on the purpose.
It goes without saying that various additives such as brighteners, semi-brighteners, auxiliary complexing agents, pH buffers, conductive salts, preservatives, antioxidants and the like can be mixed. The above surfactants include nonionic, anionic, cationic, or amphoteric surfactants, which contribute to improving the appearance, denseness, smoothness, adhesion, and uniform electrodeposition of the plating film. However, nonionic surfactants are particularly preferred. These surfactants can be used alone or in combination, and the added amount is 0.01 to 100 g /
L, preferably 0.1 to 50 g / L.

The nonionic surfactant is C₁~ C₂₀
Alkanol, phenol, naphthol, bisphenol
Le, C₁~ C_{twenty five}Alkyl phenol, aryl alk
Luphenol, C₁~ C_{twenty five}Alkyl naphthol, C₁~ C
_{twenty five}Alkoxylated phosphoric acid (salt), sorbitan ester,
Tylene phenol, polyalkylene glycol, C ₁
~ C_{twenty two}Aliphatic amine, C₁~ C_{twenty two}For aliphatic amides, etc.
Tylene oxide (EO) and / or propylene oxide
(PO) is addition-condensed in an amount of 2 to 300 mol. Follow
Alkanol, phenol, naphthol, etc.
Adduct of EO alone, adduct of PO alone, or EO
Any of adducts coexisting with PO may be used.
α-naphthol or β-naphthol ethylene oxide
Adducts (i.e., α-naphthol polyethoxylate, etc.)
Is preferred.

The C ₁ -C ₂₀ alkanol for addition condensation of ethylene oxide (EO) and / or propylene oxide (PO) is octanol, decanol, lauryl alcohol, tetradecanol, hexadecanol, stearyl alcohol, eicosanol, cetyl alcohol , Oleyl alcohol, docosanol and the like. Similarly, bisphenols include bisphenol A, bisphenol B, bisphenol F, bisphenol S, and the like. C ₁ -C ₂₅ alkylphenols include mono-, di- or trialkyl-substituted phenols such as p-butylphenol, p-isooctylphenol, p-nonylphenol, p-hexylphenol, 2,4-dibutylphenol, 2,4, 6-
Tributylphenol, p-dodecylphenol, p-
Lauryl phenol, p-stearyl phenol and the like can be mentioned. As the arylalkylphenol, 2
-Phenylisopropylphenyl and the like.

The alkyl group of the C ₁ -C ₂₅ alkyl naphthol includes methyl, ethyl, propyl, butylhexyl, octyl, decyl, dodecyl, octadecyl and the like, and may be located at any position on the naphthalene nucleus. C
_1- C ₂₅ alkoxylated phosphoric acid (salt) has the following general formula (a)
It is represented by Ra ・ Rb ・ (MO) P = O
During ... (a) (formula _(a), R a and R _b are the same or different C ₁ -C ₂₅ alkyl, provided that one may be a H.
M represents H or an alkali metal. )

As the sorbitan ester, mono-, di- or triester-converted 1,4-, 1,5- or 3,6-sorbitan such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan distearate, sorbitan diester Oleate, sorbitan mixed fatty acid ester and the like can be mentioned. Examples of the C ₁ -C ₂₂ aliphatic amine include saturated and unsaturated fatty acid amines such as propylamine, butylamine, hexylamine, octylamine, decylamine, laurylamine, stearylamine, ethylenediamine, and propylenediamine. C _1-
The C ₂₂ aliphatic amides, propionic acid, butyric acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, amides such as behenic acid.

The cationic surfactant includes a quaternary ammonium salt represented by the following general formula (b) (R ₁ · R
_{2 · R 3 · R 4 N} ) + · X - ... (b) ( Formula (b) in, X is halogen, hydroxy, C ₁ -C ₅ alkane sulfonic acid or sulfuric acid, R _1, R ₂ and R ₃ is The same or different C ₁ -C ₂₀ alkyl, and R ₄ represents C ₁ -C ₁₀ alkyl or benzyl.)
Alternatively, a pyridinium salt represented by the following general formula (c) is exemplified. _{R 6 - (C 5 H 5} N-R 5) + · X - ...
(c) (in the formula (c), C ₅ H ₅ N is a pyridine ring, X is a halogen, hydroxy, C ₁ -C ₅ alkanesulfonic 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 a salt include lauryl trimethyl ammonium salt, stearyl trimethyl ammonium salt, lauryl dimethyl ethyl ammonium salt, octadecyl dimethyl ethyl ammonium salt, dimethyl benzyl lauryl ammonium salt, cetyl dimethyl benzyl ammonium salt Octadecyldimethylbenzylammonium salt, trimethylbenzylammonium salt, triethylbenzylammonium salt, hexadecylpyridinium salt, laurylpyridinium salt, dodecylpyridinium salt, stearylamine acetate,
Laurylamine acetate, octadecylamine acetate and the like can be mentioned.

Examples of the above anionic surfactants include alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, alkyl benzene sulfonates, (mono, di, tri)
Alkyl naphthalene sulfonate and the like can be mentioned. Examples of the alkyl sulfate include sodium lauryl sulfate and sodium oleyl sulfate. Examples of the polyoxyethylene alkyl ether sulfate include sodium polyoxyethylene (EO12) nonyl ether sulfate and sodium polyoxyethylene (EO15) dodecyl ether sulfate. As polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene (E
O15) Nonyl phenyl ether sulfate and the like. Examples of the alkyl benzene sulfonate include sodium dodecyl benzene sulfonate. Examples of the (mono, di, tri) alkylnaphthalenesulfonate include sodium dibutylnaphthalenesulfonate.

Examples of the amphoteric surfactant include carboxybetaine, imidazoline betaine, sulfobetaine, aminocarboxylic acid and the like. Sulfation 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 betaine lauryldimethylaminoacetate, betaine myristyldimethylaminoacetate, betaine stearyldimethylaminoacetate, coconut oil fatty acid amidopropyldimethylaminoacetate betaine, 2-undecyl-1- Carboxymethyl-1-hydroxyethylimidazolinium betaine, 2-octyl-1-carboxymethyl-1-carboxyethylimidazolinium betaine, and the like. Examples of the sulfated and sulfonated adducts include sulfate addition of ethoxylated alkylamine. And sodium salts of sulfonated lauric acid derivatives.

Examples of the above sulfobetaine include coconut oil fatty acid amidopropyldimethylammonium-2-hydroxypropanesulfonic acid, sodium N-cocoylmethyltaurine, sodium N-palmitoylmethyltaurine and the like. Examples of the aminocarboxylic acid include dioctylaminoethylglycine, N-laurylaminopropionic acid, octyldi (aminoethyl) glycine sodium salt, and the like.

The antioxidant which can be contained in the tin, lead or tin-lead alloy bath of the present invention is intended to prevent oxidation of stannous salts in the bath, and specific examples thereof include ascorbic acid or a salt thereof. , Hydroquinone, catechol, resorcin, phloroglucin, cresol sulfonic acid or a salt thereof, phenol sulfonic acid or a salt thereof, catechol sulfonic acid or a salt thereof, hydroquinone sulfonic acid or a salt thereof, and hydrazine.

Examples of the above brightener and semi-brightener include benzaldehyde, o-chlorobenzaldehyde, 2,4,6
-Trichlorobenzaldehyde, m-chlorobenzaldehyde, p-nitrobenzaldehyde, p-hydroxybenzaldehyde, furfural, 1-naphthaldehyde, 2-naphthaldehyde, 2-hydroxy-1-naphthaldehyde, 3-acenaphthaldehyde, benzylideneacetone, pyridene Didenacetone, furfurylidene acetone, cinnamaldehyde, anisaldehyde, salicylaldehyde, crotonaldehyde, acrolein, glutaraldehyde, various aldehydes such as paraaldehyde, vanillin, triazine, imidazole, indole, quinoline, 2-vinylpyridine, aniline, phenanthroline , Neocuproin, picolinic acid, thioureas, N- (3-hydroxybutylidene) -p-sulfanilic acid, N-butylidene Rufaniru acid, N- cinnamoethyl ylidene sulfonyl 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-methylbenzothiazole, 2-aminobenzothiazole 2,2-amino-6-methoxybenzothiazole, 2-methyl-5-
Chlorobenzothiazole, 2-hydroxybenzothiazole, 2-amino-6-methylbenzothiazole, 2-
Benzothiazoles such as chlorobenzothiazole, 2,5-dimethylbenzothiazole, and 5-hydroxy-2-methylbenzothiazole.

The auxiliary complexing agent is added mainly together with the complexing agent to improve the stability of the bath. Specifically, acetic acid, alanine, cysteine, malonic acid, maleic acid, apple Acids or their salts, mono, di, triethanolamine, pyrophosphoric acid, tripolyphosphoric acid, tris
(3-hydroxypropyl) phosphine, 1-hydroxyethane-1,1-bisphosphonic acid, thioureas and the like. The pH buffer is a concept including a pH adjuster, specifically, formic acid, acetic acid, monocarboxylic acids such as propionic acid, boric acids, phosphoric acids, oxalic acid, dicarboxylic acids such as succinic acid, lactic acid, Examples include oxycarboxylic acids such as tartaric acid, and various acids such as hydrochloric acid and sulfuric acid, and various bases such as ammonium hydroxide and sodium hydroxide may be used.

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, amine salts and the like. The preservatives include boric acid, 5
-Chloro-2-methyl-4-isothiazolin-3-one, benzalkonium chloride, phenol, phenol polyethoxylate, thymol, resorcin, isopropylamine, guaiacol and the like.

The concentration of the above various additives in the tin, lead or tin-lead alloy plating bath of the present invention is arbitrarily adjusted and selected according to barrel plating, rack plating, high-speed continuous plating, rackless plating, and the like. it can. Tin, lead or tin of the present invention
As a condition for electroplating using a lead alloy plating bath, the bath temperature is 0 ° C. or higher, preferably about 10 to 50 ° C. The cathode current density is 0.01 to 150 A / in the acidic plating bath.
dm ² , preferably 0.1 to 30 A / dm ² , and 0.001 to 30 A / d in a neutral or near plating bath.
m ² , preferably 0.05 to 10 A / dm ² .

[0045]

(1) As shown in the examples described below, the tin, lead and tin-lead alloy plating baths of the present invention are basically provided on both sides or one side of a mono- or disulfide bond. Ethylene oxide, propylene oxide or hydroxypropylene oxide group contains a specific linear aliphatic hydrocarbon compound singly or repeatedly present in the molecule in the plating bath. The uniformity and denseness of the film are improved, and the solder wettability is improved. In addition, the appearance of this plating film and the improvement of solder wettability are improved over a wide pH range from the acidic region to the weak alkaline region.
This can be achieved with a tin, lead or tin-lead alloy plating bath.

(2) As shown in the present invention 2, when a specific benzoazole-based compound is used in combination with the above-mentioned linear aliphatic hydrocarbon compound, tin, lead or a tin-lead alloy plating film is formed. The appearance and solder wettability are further improved. For example, as shown in Examples described later, in a plating bath in the vicinity of acidic to weakly alkaline in which both compounds are used in combination, the uniformity, denseness, color tone, Has a clear superiority in terms of solder wettability.

[0047]

EXAMPLES Examples of various plating baths of tin and tin-lead alloy will be sequentially described below, and observation results such as the denseness and solder wettability of the electrodeposited films obtained from each plating bath will also be described. The present invention is not limited to the following embodiments, and it is needless to say that any modifications can be made within the technical idea of the present invention.

The following Examples 1 to 30 and Comparative Examples 1 to 13
Examples 1 to 13 are examples of acidic baths, of which Examples 1 to 6 are tin plating baths and Examples 7 to 13 are tin-baths.
It is an example of a lead alloy plating bath. Further, Examples 14 to 30 are examples of baths near neutrality.
Is a tin plating bath, and Examples 26 to 30 are examples of a tin-lead alloy plating bath. Further, Examples 4, 7, 11 to 12, 1
4, 17, 20, 25 and 28 are examples of the combination use of the linear aliphatic hydrocarbon compound of the present invention 1 and the benzoazole compound of the present invention 2 (particularly, Example 20 uses two kinds of benzoazole compounds. ) And other examples are examples of single use of the aliphatic hydrocarbon compound. On the other hand, Comparative Example 1 was a blank example based on Example 3 and not containing the linear aliphatic hydrocarbon compound, Comparative Example 2 was a blank example based on Example 6 and the above hydrocarbon compound, and Comparative Example 3 was A blank example of the above-mentioned hydrocarbon compound based on Example 9, Comparative Example 4 is a blank example of the above-mentioned hydrocarbon compound based on Example 10,
Comparative Example 5 is a blank example of the above-mentioned hydrocarbon compound based on Example 11, Comparative Example 6 is a blank example of the above-mentioned hydrocarbon compound based on Example 12, and Comparative Example 7 is a above-described example based on Example 17. Blank Example of Hydrocarbon Compound, Comparative Example 8
Is a blank example of the hydrocarbon compound based on Example 21, Comparative Example 9 is a blank example of the hydrocarbon compound based on Example 22, and Comparative Example 10 is the hydrocarbon compound based on Example 23. Comparative Example 11 is a blank example of the hydrocarbon compound based on Example 28, Comparative Example 12 is a blank example of the hydrocarbon compound based on Example 29, and Comparative Example 13 is Example 30. It is a blank example of the above-mentioned hydrocarbon compound as a basis.

Example 1 A tin plating bath was constructed with the following composition. Stannous sulfate (as Sn ²⁺ ) 40 g / L Concentrated sulfuric acid 120 g / L Bis (tetracontaethylene glycol) thioether 10 g / L Nonylphenol polyethoxylate (EO 12 mol) 8 g / L Benzalacetone 0.25 g / L Methacrylic acid 1 ml / L [Plating conditions] Temperature: 20 ° C. Cathode current density: 3 A / dm ² As a result of performing electroplating on a copper plate under the above conditions, a uniform and dense tin plating film having good solder wettability was obtained. Was.

Example 2 A tin plating bath was constructed with the following composition. Stannous sulfate (as Sn ²⁺ ) 60 g / L concentrated sulfuric acid 160 g / L bis (ω-hydroxyicosaethoxy) disulfide 8 g / L tristyrenated phenol-polyethoxylate (EO23 mol) 10 g / L 1-naphthaldehyde 0.2 g / L Methacrylic acid 1 ml / L Hydroquinone 1 g / L [Plating conditions] Temperature: 25 ° C. Cathode current density: 5 A / dm ² As a result of electroplating on a copper plate under the above conditions, a uniform and dense solder was obtained. A tin plating film having good wettability was obtained.

Example 3 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 20 g / L Methanesulfonic acid (as a free acid) 50 g / L Bis (triethylene glycol) thioether 15 g / L Ion-exchanged water Remaining [Plating conditions] Temperature: 25 ° C. Cathode Current density: 3 A / dm ² As a result of performing electroplating on the copper plate under the above conditions, a uniform and dense tin plating film having good solder wettability was obtained.

Comparative Example 1 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 20 g / L Methanesulfonic acid (as free acid) 50 g / L Ion-exchanged water Balance [Plating conditions] Temperature: 25 ° C. Cathode current density: 3 A / dm ² As a result of performing electroplating on the copper plate, only black coarse electrodeposition occurred in the high current density portion.

Example 4 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 40 g / L Methanesulfonic acid (as a free acid) 100 g / L Bis (pentadecaethylene glycol-pentapropylene glycol) thioether 10 g / L 2-mercaptobenzothiazole 0.02 g / L L Catechol 0.8 g / L Deionized water Remaining [Plating conditions] Temperature: 25 ° C. Cathode current density: 10 A / dm ² As a result of electroplating on a copper plate under the above conditions, uniform and dense solder wettability was obtained. A good tin plating film was obtained.

Example 5 A tin plating bath was constructed with the following composition. 2-hydroxypropanesulfonic acid-stannous (as Sn ²⁺ ) 20 g / L 2-hydroxypropanesulfonic acid (as free acid) 130 g / L bis (tripropylene glycol-decaethylene glycol) thioether 15 g / L alkyldimethylbenzyl Ammonium-methanesulfonate 0.5 g / L Cumylphenol polyethoxylate (EO15 mol) 3 g / L Ion exchange water Remaining [Plating conditions] Temperature: 30 ° C. Cathode current density: 5 A / dm ² Copper plate under the above conditions As a result of performing the electroplating thereon, a uniform and dense tin plating film having good solder wettability was obtained.

Example 6 A tin plating bath was constructed with the following composition. 2-hydroxypropanesulfonic acid-stannous (as Sn2 ⁺ ) 15 g / L 2-hydroxypropanesulfonic acid (as free acid) 80 g / L bis (dodecaethylene glycol) thioether 7 g / L tristyrenated phenol-polyethoxy Rate (EO 20 mol) 8 g / L Hydroquinone 0.8 g / L Deionized water Remaining [Plating conditions] Temperature: 25 ° C. Cathode current density: 5 A / dm ² As a result of electroplating on a copper plate under the above conditions, uniform As a result, a tin-plated film with good solder wettability was obtained.

Comparative Example 2 A tin plating bath was constructed with the following composition. 2-hydroxypropanesulfonic acid-stannous (as Sn ²⁺ ) 15 g / L 2-hydroxypropanesulfonic acid (as free acid) 80 g / L tristyrenated phenol-polyethoxylate (20 mol EO) 8 g / L hydroquinone 0 0.8 g / L ion-exchanged water balance [Plating conditions] Temperature: 25 ° C Cathode current density: 5 A / dm ² As a result of electroplating on a copper plate under the above conditions, the plating film obtained was uniform and dense. Both of the properties and the solder wettability were inferior to those of Example 6.

Example 7 A tin-lead alloy plating bath having the following composition was prepared. Stannous borofluoride (as Sn ²⁺ ) 80 g / L Lead borofluoride (as Pb ²⁺ ) 5 g / L Borofluoric acid (as free acid) 160 g / L Bis (hexaethylene glycol) thioether 12 g / L Laurylamine polyethoxy Rate (15 mol of EO) 7 g / L 2-mercaptobenzimidazole 0.2 g / L [Plating conditions] Temperature: 30 ° C. Cathode current density: 12 A / dm ² As a result of electroplating on a copper plate under the above conditions, uniform Thus, a dense tin-lead alloy plating film having good solder wettability was obtained.

Example 8 A tin-lead alloy plating bath having the following composition was prepared. Stannous borofluoride (as Sn ²⁺ ) 50 g / L Lead borofluoride (as Pb ²⁺ ) 10 g / L Borofluoric acid (as free acid) 140 g / L Bis (decaethylene glycol-monoglycerol) thioether 15 g / L α -Naphthol polyethoxylate (EO 10 mol) 10 g / L Benzalacetone 0.2 g / L Methacrylic acid 1 ml / L [Plating conditions] Temperature: 25 ° C. Cathode current density: 8 A / dm ² Electricity on copper plate under the above conditions As a result of plating, a uniform tin-plated tin-lead alloy plating film having good solder wettability was obtained.

Example 9 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 54 g / L Lead methanesulfonate (as Pb ²⁺ ) 6 g / L Methanesulfonic acid (as free acid) 120 g / L Bis (icosaethylene glycol) thioether 4 g / L Bisphenol A polyethoxylate (EO13 mol) 5 g / L Catechol 0.8 g / L Deionized water Remaining [Plating conditions] Temperature: 40 ° C. Cathode current density: 10 A / dm ² Electroplating is performed on a copper plate under the above conditions. As a result, a uniform tin-lead alloy plating film having good solder wettability was obtained.

Comparative Example 3 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 54 g / L Lead methanesulfonate (as Pb ²⁺ ) 6 g / L Methanesulfonic acid (as a free acid) 120 g / L Bisphenol A polyethoxylate (13 mol of EO) 5 g / L L Catechol 0.8 g / L Ion-exchanged water Remaining [Plating conditions] Temperature: 40 ° C. Cathode current density: 10 A / dm ² As a result of performing electroplating on a copper plate under the above conditions, the plating film obtained was uniform. All were inferior to the ninth embodiment in the properties, denseness and solder wettability.

Example 10 A tin-lead alloy plating bath having the following composition was prepared. 2-Hydroxyethane-stannous sulfonate (as Sn ²⁺ ) 18 g / L Lead 2-hydroxyethane sulfonate (as Pb ²⁺ ) 2 g / L 2-hydroxypropane-sulfonic acid (as free acid) 100 g / L Bis (icosaethylene glycol) thioether 20 g / L Hydroquinone 0.5 g / L Deionized water Remaining [Plating conditions] Temperature: 30 ° C. Cathode current density: 5 A / dm ² Electroplating was performed on a copper plate under the above conditions. As a result, a uniform tin-lead alloy plating film having good solder wettability was obtained.

Comparative Example 4 A tin-lead alloy plating bath having the following composition was prepared. 2-Hydroxyethane-stannous sulfonate (as Sn ²⁺ ) 18 g / L Lead 2-hydroxyethane sulfonate (as Pb ²⁺ ) 2 g / L 2-hydroxypropane-sulfonic acid (as free acid) 100 g / L Hydroquinone 0.5 g / L Deionized water Remainder [Plating conditions] Temperature: 30 ° C Cathode current density: 5 A / dm ² As a result of electroplating on a copper plate under the above conditions, a black There was only dressing.

Example 11 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 54 g / L Lead methanesulfonate (as Pb ²⁺ ) 6 g / L Methanesulfonic acid (as a free acid) 80 g / L Bis (ω-hydroxydodecaethoxy) disulfide 4 g / L L Bisphenol A polyethoxylate (EO13 mol) 5 g / L Benzoic acid 0.3 g / L 2-mercaptobenzimidazole 0.1 g / L Catechol 0.8 g / L Ion exchange water Balance [Plating conditions] Temperature: 30 ° C. Cathode Current density: 10 A / dm ² As a result of performing electroplating on the copper plate under the above-mentioned conditions, a uniform and dense tin-lead alloy plating film having good solder wettability was obtained.

Comparative Example 5 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 54 g / L Lead methanesulfonate (as Pb ²⁺ ) 6 g / L Methanesulfonic acid (as a free acid) 80 g / L Bisphenol A polyethoxylate (EO13 mol) 5 g / L L Benzoic acid 0.3 g / L 2-mercaptobenzimidazole 0.1 g / L Catechol 0.8 g / L Deionized water Remaining [Plating conditions] Temperature: 30 ° C. Cathode current density: 10 A / dm ² Copper plate under the above conditions As a result of the electroplating, the resulting plating film was inferior to Example 11 in terms of uniformity, denseness, and solder wettability.

Example 12 A tin-lead alloy plating bath was constructed with the following composition. 2-Hydroxyethane-stannous sulfonate (as Sn ²⁺ ) 18 g / L Lead 2-hydroxyethane sulfonate (as Pb ²⁺ ) 2 g / L 2-hydroxypropane-sulfonic acid (as free acid) 100 g / L Bis (icosaethylene glycol) thioether 6 g / L 6-methoxy-2-mercaptobenzothiazole 0.05 g / L Laurylamine polypropoxylate (7 mol of PO) -polyethoxylate (12 mol of EO) 8 g / L Hydroquinone 0.5 g / L L Ion-exchanged water Remaining [Plating conditions] Temperature: 30 ° C Cathode current density: 5 A / dm ² As a result of electroplating on a copper plate under the above-mentioned conditions, a uniform and dense tin-lead alloy with good solder wettability was obtained. A gold plated film was obtained.

Comparative Example 6 A tin-lead alloy plating bath having the following composition was prepared. 2-Hydroxyethane-stannous sulfonate (as Sn ²⁺ ) 18 g / L Lead 2-hydroxyethane sulfonate (as Pb ²⁺ ) 2 g / L 2-hydroxypropane-sulfonic acid (as free acid) 100 g / L 6-methoxy-2-mercaptobenzothiazole 0.05 g / L laurylamine polypropoxylate (PO7 mol) -polyethoxylate (EO12 mol) 8 g / L hydroquinone 0.5 g / L ion-exchanged water balance [Plating conditions] Temperature : 30 ° C Cathode current density: 5 A / dm ² As a result of performing electroplating on a copper plate under the above conditions, the resulting plated film was more uniform than Example 12 in terms of uniformity, denseness, and solder wettability. Was inferior.

Example 13 A tin-lead alloy plating bath having the following composition was prepared. Stannous phenolsulfonate (as Sn ²⁺ ) 30 g / L Lead phenolsulfonate (as Pb ²⁺ ) 6 g / L Phenolsulfonic acid (as free acid) 180 g / L Bis (pentadecaethylene glycol) thioether 8 g / L Lauryl alcohol polyethoxylate (EO15 mol) -polypropoxylate (PO5 mol) 12 g / L 2-hydroxynaphthaldehyde 0.2 g / L Methacrylic acid 1.5 ml / L [Plating conditions] Temperature: 30 ° C. Cathode current density: 12 A / dm ² As a result of performing electroplating on the copper plate under the above-mentioned conditions, a uniform and dense tin-lead alloy plating film having good solder wettability was obtained.

Example 14 A tin plating bath was constructed with the following composition. Stannous sulfate (as Sn ²⁺ ) 30 g / L Sulfuric acid 100 g / L Bis (dodecaethylene glycol) thioether 12 g / L Sodium 3- (2-benzothiazolylthio) -1-propanesulfonate 0.3 g / L Diethylenetriamine Pentaacetic acid 1.5 mol / L [Plating conditions] pH (adjusted with potassium hydroxide): 5.5 Temperature: 30 ° C. Cathode current density: 5 A / dm ² Result of electroplating on copper plate under the above conditions Thus, a tin plating film having a white color and good solder wettability was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Example 15 A tin plating bath was constructed with the following composition. Stannous sulfate (as Sn ²⁺ ) 40 g / L Sulfuric acid 100 g / L Bis (triacontaethylene glycol) thioether 20 g / L Gluconolactone 1.2 mol / L [Plating conditions] pH (adjusted with ammonia): 5. 5 Temperature: 25 ° C. Cathode current density: 3 A / dm ² As a result of performing electroplating on a copper plate under the above conditions, a tin-plated film having a good solder wettability was obtained as a white color. Also, 3
Microscopic observation with a SEM photograph of 500 times confirmed that the film was uniform and dense.

Example 16 A tin plating bath was constructed with the following composition. Stannous sulfate (as Sn ²⁺ ) 5 g / L Sulfuric acid 70 g / L Bis (ω-hydroxyicosaethoxy) disulfide 10 g / L Citric acid 0.4 mol / L Polyoxyethylene (EO 30 mol) Polyoxypropylene (PO25 mol -Glycol ether 2 g / L [Plating conditions] pH (adjusted with ethylenediamine): 6.5 Temperature: 25 ° C Cathode current density: 1 A / dm ² As a result of electroplating on a copper plate under the above conditions, white color was obtained. As a result, a tin plating film having good solder wettability was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Example 17 A tin plating bath was constructed with the following composition. Stannous phenolsulfonic acid (as Sn ²⁺ ) 20 g / L Phenolsulfonic acid (as free acid) 60 g / L Bis (ω-hydroxypentapropoxy-pentadecaethoxy) disulfide 8 g / L Potassium gluconate 0.5 mol / L Ethylenediamine polypropoxylate (PO50 mol) -polyethoxylate (EO45 mol) 2 g / L β-naphthol polyethoxylate (EO10 mol) 1 g / L 2-methylmercaptobenzothiazole 0.05 g / L Deionized water balance [Plating conditions PH (adjusted with potassium hydroxide): 5.5 Temperature: 25 ° C. Cathode current density: 3 A / dm ² As a result of electroplating on a copper plate under the above conditions, tin was white and had good solder wettability. A plating film was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Comparative Example 7 A tin plating bath was constructed with the following composition. Stannous phenolsulfonate (as Sn ²⁺ ) 20 g / L Phenolsulfonic acid (as free acid) 60 g / L Potassium gluconate 0.5 mol / L Ethylenediamine polypropoxylate (PO50 mol) -Polyethoxylate (EO45 mol) 2 g / L β-naphthol polyethoxylate (10 mol of EO) 1 g / L 2-methylmercaptobenzothiazole 0.05 g / L Deionized water Remainder [Plating conditions] pH (adjusted with potassium hydroxide): 5.5 temperature : 25 ° C. Cathode current density: 3 A / dm ² As a result of electroplating on a copper plate under the above conditions, the plating film obtained was gray and the solder wettability was as in Example 1 above.
It was worse than 7. Further, when the plating film was microscopically observed with a SEM photograph at a magnification of 3500, both the uniformity and the denseness were inferior to those of Example 17.

Example 18 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 25 g / L Sodium acetate 80 g / L Bis (icosaethylene glycol) thioether 10 g / L Tartaric acid 0.7 mol / L Boric acid 10 g / L Ion exchange water Balance [Plating conditions] pH (adjusted with potassium hydroxide / triethylamine = 1/1): 5.0 Temperature: 25 ° C. Cathode current density: 3 A / dm ² As a result of electroplating on a copper plate under the above conditions, white solder wet A tin plating film having good properties was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Example 19 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 30 g / L Methanesulfonic acid (as a free acid) 80 g / L Bis (decaethylene glycol) thioether 12 g / L Sodium glucoheptonate 0.5 mol / L Dodecyldimethylaminoacetic acid betaine 0 0.5 g / L 5-chloro-2-methyl-4-isothiazolin-3-one 0.5 g / L ion-exchanged water balance [Plating conditions] pH (adjusted with ammonia): 3.0 Temperature: 25 ° C. Cathode current Density: 3 A / dm ² As a result of performing electroplating on the copper plate under the above-mentioned conditions, a white tin-plated film having good solder wettability was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Example 20 A tin plating bath was constructed with the following composition. Stannous methanesulfonic acid (as Sn ²⁺ ) 20 g / L Methanesulfonic acid (as free acid) 80 g / L Bis (ω-hydroxypentapropoxy-pentadecaethoxy) disulfide 20 g / L 2-mercaptobenzoxazole 0.2 g / L 6-chloro-2-mercaptobenzothiazole 0.1 g / L sodium gluconate 1.2 mol / L boric acid 30 g / L ion-exchanged water balance [Plating conditions] pH (adjusted with ammonia): 3.0 temperature : 30 ° C Cathode current density: 3 A / dm ² As a result of performing electroplating on the copper plate under the above conditions, a tin-plated film having a good solder wettability was obtained as a white color. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Example 21 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 15 g / L Methanesulfonic acid (as a free acid) 85 g / L Bis (dodecaethylene glycol) thioether 5 g / L Citric acid 0.6 mol / L Sodium citrate 0.6 mol / L L Ascorbic acid 2 g / L [Plating conditions] pH (adjusted with sodium hydroxide): 9.0 Temperature: 30 ° C. Cathode current density: 0.1 A / dm ² Electroplating was performed on the copper plate under the above conditions. As a result, a white tin-plated film having good solder wettability was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Comparative Example 8 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 15 g / L Methanesulfonic acid (as free acid) 85 g / L Citric acid 0.6 mol / L Sodium citrate 0.6 mol / L Ascorbic acid 2 g / L [Plating conditions] pH (adjusted with sodium hydroxide): 9.0 Temperature: 30 ° C. Cathode current density: 0.1 A / dm ² As a result of electroplating on a copper plate under the above conditions, the resulting plating film was gray. Yes, the solder wettability was measured in Example 2 above.
Inferior to one. Further, when the plating film was observed with a SEM photograph at a magnification of 3500, both the uniformity and the denseness were inferior to those of Example 21.

Example 22 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 20 g / L Methanesulfonic acid (as a free acid) 80 g / L Bis (pentadecaethylene glycol) thioether 12 g / L Octylphenol polyethoxylate (EO 15 mol) 5 g / L 2− Alkyl-N-carboxymethyl-N-hydroxyethyl-imidazolium betaine 0.05 g / L Sodium gluconate 1.2 mol / L Phenol polyethoxylate (EO4 mol) 2 g / L Ion exchange water Balance [Plating conditions] pH (water (Adjusted with sodium oxide): 2.0 Temperature: 30 ° C. Cathode current density: 3 A / dm ² As a result of electroplating on a copper plate under the above conditions, a tin-plated film with white and good solder wettability was obtained. Was done. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Comparative Example 9 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 20 g / L Methanesulfonate (as free acid) 80 g / L Octylphenol polyethoxylate (15 mol EO) 5 g / L 2-alkyl-N-carboxymethyl-N-hydroxyethyl -Imidazolium betaine 0.05 g / L sodium gluconate 1.2 mol / L phenol polyethoxylate (EO4 mol) 2 g / L ion-exchanged water balance [Plating conditions] pH (adjusted with sodium hydroxide): 2.0 temperature Degree: 30 ° C. Cathode current density: 3 A / dm ² As a result of electroplating on a copper plate under the above conditions, the resulting plating film was gray and the solder wettability was as in Example 2 above.
Inferior to 2. Further, when the plating film was observed with a 3500-fold SEM photograph, both the uniformity and the denseness were inferior to those of Example 22.

Example 23 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 20 g / L Methanesulfonic acid (as a free acid) 70 g / L Bis (pentadecaethylene glycol) thioether 20 g / L Sodium gluconate 1.2 mol / L Ion-exchanged water Balance [ Plating conditions] pH (adjusted with ammonia): 2.0 Temperature: 30 ° C. Cathode current density: 3 A / dm ² As a result of electroplating on a copper plate under the above conditions, tin was white and had good solder wettability. A plating film was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Comparative Example 10 A tin plating bath was constructed with the following composition. Stannous methanesulfonate (as Sn ²⁺ ) 20 g / L Methanesulfonic acid (as a free acid) 70 g / L Sodium gluconate 1.2 mol / L Ion-exchanged water The balance [Plating conditions] pH (adjusted with ammonia): 2.0 Temperature: 30 ° C. Cathode current density: 3 A / dm ² As a result of electroplating on a copper plate under the above conditions, the plating film obtained was gray and the solder wettability was as described in Example 2 above.
Inferior to 3. Further, when the plating film was observed with a 3500-fold SEM photograph, both the uniformity and the denseness were inferior to those of Example 23.

Example 24 A tin plating bath was constructed with the following composition. Stannous ethanesulfonate (as Sn ²⁺ ) 45 g / L Ethanesulfonic acid (as free acid) 100 g / L S, S'-bis (pentadecaethylene glycol) -ethylenedithioether 10 g / L Citric acid 1.0 mol / L Boric acid 30g / L Deionized water Remainder [Plating conditions] pH (adjusted with potassium hydroxide): 5.5 Temperature: 25 ° C Cathode current density: 5A / dm ² Electroplating on copper plate under the above conditions As a result, a tin plating film having a white color and good solder wettability was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Example 25 A tin plating bath was constructed with the following composition. 2-hydroxypropane-stannous sulfonate (as Sn ²⁺ ) 20 g / L methanesulfonic acid (as free acid) 50 g / L bis (ω-hydroxypentapropoxy-pentadecaethoxy) disulfide 8 g / L potassium gluconate 0 0.5 mol / L polyethoxylate (EO 26 mol) polypropoxylate (PO 30 mol) -block copolymer 2 g / L β-naphthol polyethoxylate (EO 10 mol) 1 g / L 2-benzothiazolethioacetic acid 0.05 g / L ion exchange Water Remaining [Plating conditions] pH (adjusted with potassium hydroxide): 5.5 Temperature: 25 ° C Cathode current density: 3 A / dm ² As a result of electroplating on a copper plate under the above conditions, white solder wet A tin plating film having good properties was obtained. Also, 3
Observation with a 500 times SEM photograph confirmed that the film was uniform and dense.

Example 26 A tin-lead alloy plating bath having the following composition was prepared. Stannous chloride (as Sn ²⁺ ) 25 g / L Lead acetate (as Pb ²⁺ ) 2 g / L Methanesulfonic acid (as free acid) 50 g / L Bis (decaethylene glycol monoglycerol) -thioether 8 g / L gluconic acid Sodium 0.5 mol / L Sodium malate 0.4 mol / L Polyethylene glycol-octyl phenyl ether (EO 15 mol) 7 g / L Ascorbic acid 2 g / L Deionized water Remainder [Plating conditions] pH (adjusted with potassium hydroxide): 6.0 Temperature: 25 ° C. Cathode current density: 3 A / dm ² As a result of performing electroplating on a copper plate under the above-described conditions, a tin-lead alloy plating film having white and good solder wettability was obtained.
In addition, observation with a 3500-fold SEM photograph confirmed that the film was uniform and dense.

Example 27 A tin-lead alloy plating bath having the following composition was prepared. Stannous borofluoride (as Sn ²⁺ ) 25 g / L Lead borofluoride (as Pb ²⁺ ) 2 g / L borofluoric acid (as free acid) 50 g / L Bis (decaethylene glycol-monoglycerol) thioether 8 g / L L Tartaric acid 0.5 mol / L Boric acid 30 g / L Polyethylene glycol-octylphenyl ether (EO15 mol) 7 g / L Ascorbic acid 2 g / L Deionized water Remaining [Plating conditions] pH (adjusted with potassium hydroxide): 6. 0 Temperature: 25 ° C. Cathode current density: 3 A / dm ² As a result of performing electroplating on a copper plate under the above-mentioned conditions, a tin-lead alloy plating film having good solder wettability was obtained.
In addition, observation with a 3500-fold SEM photograph confirmed that the film was uniform and dense.

Example 28 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 28 g / L Lead methanesulfonate (as Pb ²⁺ ) 2 g / L Methanesulfonic acid (as a free acid) 50 g / L Bis (dodecaethylene glycol) thioether 10 g / L 6 -Amino-2-mercaptobenzothiazole 0.1 g / L tristyrenated phenol -Polyethoxylate (EO 23 mol) 8 g / L Gluconolactone 0.8 mol / L Ascorbic acid 2 g / L Deionized water Balance [Plating conditions] pH (Adjusted with potassium hydroxide): 4.0 Temperature: 25 ° C. Cathode current density: 2 A / dm ² As a result of electroplating on a copper plate under the above conditions, tin-lead having good solder wettability was white. An alloy plating film was obtained.
In addition, observation with a 3500-fold SEM photograph confirmed that the film was uniform and dense.

Comparative Example 11 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 28 g / L Lead methanesulfonate (as Pb ²⁺ ) 2 g / L Methanesulfonic acid (as free acid) 50 g / L 6-amino-2-mercaptobenzothiazole 1 g / L tristyrenated phenol-polyethoxylate (EO23 mol) 8 g / L gluconolactone 0.8 mol / L ascorbic acid 2 g / L ion-exchanged water Residual [Plating conditions] pH (adjusted with potassium hydroxide): 4 0.0 Temperature: 25 ° C. Cathode current density: 2 A / dm ² As a result of performing electroplating on a copper plate under the above conditions, the plating film obtained was gray and the solder wettability was as described in Example 2 above.
8 was inferior. Further, when the plating film was observed with a 3500-fold SEM photograph, both the uniformity and the denseness were inferior to those of Example 28.

Example 29 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 15 g / L Lead methanesulfonate (as Pb ²⁺ ) 0.5 g / L Methanesulfonic acid (as free acid) 100 g / L Bis (decaethylene glycol) thioether 10 g / L L Triethylenetetramine hexaacetic acid 1.1 mol / L Malonic acid 5 g / L [Plating conditions] pH (adjusted with ammonia): 4.5 Temperature: 15 ° C Cathode current density: 0.8 A / dm ² As a result of electroplating on the copper plate, a tin-lead alloy plating film having a good white solder wettability was obtained.
In addition, observation with a 3500-fold SEM photograph confirmed that the film was uniform and dense.

Comparative Example 12 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 15 g / L Lead methanesulfonate (as Pb ²⁺ ) 0.5 g / L Methanesulfonic acid (as free acid) 100 g / L Triethylenetetramine hexaacetic acid 1.1 mol / L L Malonic acid 5 g / L [Plating conditions] pH (adjusted with ammonia): 4.5 Temperature: 15 ° C. Cathode current density: 0.8 A / dm ² As a result of electroplating on a copper plate under the above conditions, The obtained plating film was gray, and the solder wettability was as described in Example 2 above.
9 was inferior. Further, when the plating film was observed with a SEM photograph at a magnification of 3500, both the uniformity and the denseness were inferior to those of Example 29.

Example 30 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 28 g / L Lead methanesulfonate (as Pb ²⁺ ) 2 g / L Methanesulfonic acid (as free acid) 50 g / L S, S′-bis (tripropylene glycol ico (Ethylene glycol) -ethylene dithioether 15 g / L gluconolactone 0.8 mol / L ascorbic acid 2 g / L Deionized water balance [Plating conditions] pH (adjusted with potassium hydroxide): 4.0 Temperature: 25 ° C Cathode current density: 2 A / dm ² As a result of performing electroplating on the copper plate under the above-mentioned conditions, a tin-lead alloy plating film having white and good solder wettability was obtained.
In addition, observation with a 3500-fold SEM photograph confirmed that the film was uniform and dense.

Comparative Example 13 A tin-lead alloy plating bath having the following composition was prepared. Stannous methanesulfonate (as Sn ²⁺ ) 28 g / L Lead methanesulfonate (as Pb ²⁺ ) 2 g / L Methanesulfonic acid (as free acid) 50 g / L Gluconolactone 0.8 mol / L Ascorbic acid 2 g / L ion exchange water balance [Plating conditions] pH (adjusted with potassium hydroxide): 4.0 Temperature: 25 ° C Cathode current density: 2 A / dm ² As a result of electroplating on a copper plate under the above conditions, The obtained plating film was gray, and the solder wettability was as described in Example 3 above.
It was inferior to 0. Further, when the plating film was observed with a SEM photograph at a magnification of 3500, both the uniformity and the denseness were inferior to those of Example 30.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazumasa Fujimura 5-26 Nishiyanagihara-cho, Hyogo-ku, Kobe-shi, Hyogo Inside Ishihara Pharmaceutical Co., Ltd. Inside of Daiwa Chemicals Research Laboratory Co., Ltd. (72) Inventor Takao Takeuchi Inside of 21 Daiwa Kasei Research Laboratories at 21 Futami-cho, Futami-cho, Akashi City, Hyogo Prefecture F term (reference) 4K023 AA17 AA18 AB33 BA06 BA08 BA13 BA21 BA29 CA04 CB03 CB04 CB08 CB13 CB21 CB28 CB33 DA02 DA03 DA06 DA07 DA08

Claims (7)

[Claims] (A) a soluble metal salt comprising a stannous salt, a lead salt, and a soluble mixture of a stannous salt and a lead salt; (B) a soluble metal salt represented by the following general formula (a): H- (OA) a- (S) bAB- (AO) c-H (A) (where AO is represented by the above general formula (A) Ethylene oxide, propylene oxide, hydroxypropylene oxide,
However, when a is 2 or more and AO is repeated, each AO in the repetition may be different from each other; A is ethylene, propylene, hydroxypropylene, provided that
When A is hydroxypropylene, ethylene oxide and propylene oxide can be added to the hydroxyl group. Further, each of A in (OA) a and A and (AO) c may be different from each other; An integer, where a ≠
0, B = S, c ≠ 0, and a + c = 2
B is 1 or 2; B is 1 or 2; and B is 1 or 2 when A is hydroxypropylene;
Is S or O when b = 1 and O when b = 2. ), A tin, lead and tin-lead alloy plating bath. 2. A benzoazole-based compound represented by the following general formula (b): (Wherein X is O, S, NH; R ₁ is SH, SR
(R is COOM, SO ₃ M (M is hydrogen, alkali metal,
Alkaline earth metals, ammonia, C ₁ -C ₆ alkyl which is not the or substituted substituted by amines)), S- allyl,
S-aryl; R ₂ , R ₃ , R ₄ and R ₅ may be the same or different, and each of H, SH, OH, OR (R is COO
H-substituted or unsubstituted C ₁ -C ₆ alkyl),
SR (R is C ₁ substituted or unsubstituted with COOH
-C ₆ alkyl), halogen, COOH, NH _2, NO _2,
NRR '(R, R' are each C ₁ -C ₆ alkyl, or taken together form a ring), SO ₃ M (M is hydrogen, an alkali metal, alkaline earth metal, ammonia, amine). The tin according to claim 1, wherein the tin contains
Lead and tin-lead alloy plating bath. 3. The bath of claim 1, further comprising an organic sulfonic acid. 4. The tin, lead and tin-lead alloy plating bath according to claim 1, wherein the plating bath contains a complexing agent and has a pH of 1.5 to 9.0. . 5. The tin, lead and tin-lead alloy plating according to claim 4, wherein said tin, lead and tin-lead alloy plating contains at least one of an alkali metal salt, an alkaline earth metal salt, an ammonium salt and an amine salt of an organic sulfonic acid. bath. 6. An additive selected from the group consisting of surfactants, brighteners, semi-brighteners, leveling agents, auxiliary complexing agents, pH buffers, conductive salts, preservatives, and antioxidants. The tin, lead and tin-lead alloy plating bath according to any one of claims 1 to 5, which contains at least one kind. 7. The tin, lead and tin-lead alloy plating bath according to claim 6, wherein the surfactant is a nonionic surfactant.