Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
Title of Invention: COPPER-TIN ALLOY PLATING BATH
Technical Field
[0001]
The present invention relates to a copper-tin alloy
plating bath.
Background Art
[0002]
Nickel plating has been widely used in electroplating.
However, there are indications that nickel plating has a nickel
allergy problem such that the metallic element (nickel) contained
in the plating film causes skin rashes or inflammation. There is
thus a need for a technique that replaces nickel plating.
[0003]
Meanwhile, copper-tin alloys are known to have a white
appearance and film properties that are comparable to those of
nickel. For this reason, copper-tin alloy plating is drawing
attention as an alternative to nickel plating.
[0004]
Cyanide ion-containing plating baths (cyanide baths)
have been used for copper-tin alloy plating, but are problematic
in terms of the work environment and wastewater treatment
regulations. In recent years, pyrophosphate baths (e.g., Patent
Literature 1 to 3), acidic baths (e.g., Patent Literature 4 and
5), and the like have been proposed as cyanide-ion-free
(hereinafter may be referred to as "non-cyanide"), copper-tin
alloy baths. However, when a pyrophosphate bath is used, compared
with the case in which a cyanide bath is used, the fc.Lmed plating
film has high internal stress, and therefore, cracks are
generated during plating, thus making it difficult to thicken the
plating film. In acidic baths, the deposition potentials of
copper and tin are not adjusted; therefore, when an acidic bath
is used for barrel plating with a large variation in the current
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density, copper is preferentially deposited, resulting in a large
variation in the alloy composition.
[0005]
There is thus a demand for a plating bath that enables
thickening of a plating film as in the case of a cyanide bath,
and that can also be applied to barrel plating.
Citation List
Patent Literature
[0006]
PTL 1: JPH10-102278A
PTL 2: JP2001-295092A
PTL 3: JP2004-035980A
PTL 4: JP2009-161804A
PTL 5: JP2010-189753A
Summary of Invention
Technical Problem
[0007]
The present invention has been accomplished in view of
the above-described problems of the conventional techniques. A
primary object of the present invention is to provide a copper-
tin alloy plating bath that allows for film thickening without
using cyanide ions, and that can also be applied to barrel
plating.
Solution to Problem
[0008]
The present inventors conducted extensive research to
achieve the above object, and found that a copper-tin alloy
plating bath that allows for film thickening without using
cyanide ions and that can also be applied to barrel plating can
be obtained by using a specific sulfur-containing compound and a
specific hydroxyl group-containing aromatic compound. The present
invention has been accomplished through further research based on
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this finding.
[0009]
More specifically, the present invention provides the
following copper-tin alloy plating bath and the like.
Item 1. A copper-tin alloy plating bath comprising an aqueous
solution containing a water-soluble copper compound, a water-
soluble divalent tin compound, a sulfur-containing compound
represented by formula (1):
R-(CHJI-S-(CHAm-S-(CHAn-R (1),
wherein R is H, OH, or SO3Na, and 1, m, and n are each
independently an integer of 0 to 3,
and a hydroxyl group-containing aromatic compound.
Item 2. The copper-tin alloy plating bath according to Item 1,
wherein the water-soluble copper compound is present in an amount
such that the amount of copper ions is 1 to 60 g/L, the water-
soluble divalent tin compound is present in an amount such that
the amount of divalent tin ions is 5 to 40 g/L, the sulfur-
containing compound is present in an amount of 5 to 500 g/L, and
the hydroxyl group-containing aromatic compound is present in an
amount of 1 to 50 g/L.
Item 3. The copper-tin alloy plating bath according to Item 1 or
2, wherein the sulfur-containing compound is at least one member
selected from the group consisting of methanedithiol, 1,2-
ethanedithiol, 1,3-propanedithiol, 3,6-dithia-1,8-octanediol, and
bis-(sodium sulfopropy1)-disulfide.
Item 4. The copper-tin alloy plating bath according to any one of
Items 1 to 3, wherein the hydroxyl group-containing aromatic
compound is at least one member selected from the group
consisting of phenol, catechol, hydroquinone, resorcinol,
pyrogallol, p-cresolsulfonic acid, sodium ascorbate, and sodium
erythorbate.
Item 5. The copper-tin alloy plating bath according to any one of
Items 1 to 4, wherein the aqueous solution further contains a
nonionic surfactant, and an aromatic ketone or an aromatic
aldehyde.
- 4 -
Item 6. A method for copper-tin alloy plating, the method
comprising performing electrolysis using an object to be plated
as a cathode in the copper-tin alloy plating bath according to
any one of Items 1 to 5.
Item 7. An article comprising a copper-tin alloy plating film
formed by the method according to Item 6.
Item 8. A copper-tin alloy plating bath comprising an
aqueous solution having a pH of 4.5 or less, the aqueous
solution containing a water-soluble divalent copper
compound, a water-soluble divalent tin compound, a sulfur-
containing compound represented by formula (1):
R- (CH2)1-8- (CH2).-S- (CH2) n-R (1),
wherein R is H, OH, or SO3Na, and 1, m, and n are each
independently an integer of 0 to 3, a hydroxyl group-
containing aromatic compound, a surfactant, and a leveler,
the surfactant being at least one nonionic surfactant
selected from the group consisting of polyoxyethylene
alkylamines, polyoxyalkylene phenyl ethers, and
polyoxyalkylene naphthyl ethers, the leveler being at least
one aromatic ketone or aromatic aldehyde selected from the
group consisting of benzalacetone, cinnamaldehyde,
a-methylcinnamaldehyde, a-hexylcinnamaldehyde,
a-amylcinnamaldehyde, cuminaldehyde, benzaldehyde, and
anisaldehyde, the water-soluble divalent copper compound
being present in an amount such that the amount of divalent
copper ions is 1 to 60 g/L, the water-soluble divalent tin
compound being present in an amount such that the amount of
divalent tin ions is 5 to 40 g/L, the sulfur-containing
compound being present in an amount of 5 to 500 g/L, the
hydroxyl group-containing aromatic compound being present
in an amount of 1 to 50 g/L, the surfactant being present
in an amount of 0.1 to 40 g/L, the leveler being present in
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an amount of 0.01 to 10 g/L and the surfactant:leveler
ratio being 1:1 to 100:1.
Advantageous Effects of Invention
[0010]
Since a specific sulfur-containing compound and a
specific hydroxyl group-containing aromatic compound are used in
combination in the copper-tin alloy plating bath of the present
invention, an alloy film containing copper and tin at any ratio
can be obtained. In addition, since a specific sulfur-containing
compound is used as a complexing agent in the copper-tin alloy
plating bath of the present invention, cracking is less likely to
occur compared with the case in which hitherto known
pyrophosphate baths are used, and the plating film can be
thickened without using a cyanide bath. Further, since, regarding
the copper-tin alloy plating bath of the present invention, the
current density has a small influence on the alloy ratio compared
with the case in which hitherto known acidic baths are used, the
copper-tin alloy plating bath of the present invention can also
be applied to barrel plating with a large variation in the
current density. Moreover, a plating film having an excellent
bright appearance can be obtained by further adding a nonionic
surfactant, and an aromatic ketone or an aromatic aldehyde to the
copper-tin alloy plating bath.
Brief Description of Drawings
[0011]
Fig. 1 is a diagram showing the relationship between
the current density of a copper-tin alloy plating bath and the
copper content of a plating film.
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Description of Embodiments
[0012]
The copper-tin alloy plating bath of the present
invention is described in detail below.
[0013]
The copper-tin alloy plating bath of the present
invention comprises an aqueous solution containing a water-
soluble copper compound and a water-soluble divalent tin compound
as metal sources, a sulfur-containing compound represented by
formula (1):
R- (CH2) 1-S- (CH2) m-S- (CH2) n-R (1) r
wherein R is H, OH, or SO3Na, and 1, m, and n are each
independently an integer of 0 to 3, as a complexing agent, and a
hydroxyl group-containing aromatic compound.
[0014]
The water-soluble copper compound, which is a copper
ion source, is not particularly limited as long as it is a water-
soluble compound containing divalent copper as a copper component.
Specific examples of water-soluble copper compounds include
copper(II) chloride, copper(II) sulfate, copper(II) nitrate,
copper(II) carbonate, copper(II) oxide, copper(II) acetate,
copper(II) methanesulfonate, copper(II) sulfamate, copper(II)
fluoride, copper(II) 2-hydroxyethanesulfonate, copper(II) 2-
hydroxypropanesulfonate, copper(II) pyrophosphate, and the like.
Among these copper compounds, copper(II) sulfate is preferable.
These water-soluble copper compounds can generally be used singly,
or in a combination of two or more. The concentration of the
water-soluble copper compound is, for example, such that the
copper ion concentration is about 1 to 60 g/L, and preferably
about 10 to 40 g/L.
[0015]
The water-soluble divalent tin compound, which is a tin
ion source, is not particularly limited as long as it is a water-
soluble compound containing divalent tin as a tin component.
Specific examples of water-soluble divalent tin compounds include
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stannous chloride, stannous sulfate, stannous acetate, stannous
pyrophosphate, stannous methanesulfonate, stannous sulfamate,
stannous gluconate, stannous tartrate, stannous oxide, stannous
fluoroborate, stannous 2-hydroxyethanesulfonate, stannous 2-
hydroxypropanesulfonate, and the like. Among these tin compounds,
stannous sulfate is preferable. These water-soluble divalent tin
compounds can generally be used singly, or in a combination of
two or more. The concentration of the water-soluble divalent tin
compound is, for example, such that the divalent tin ion
concentration is about 5 to 40 g/L, and preferably about 5 to 25
g/L.
[0016]
The proportions of the water-soluble copper compound
and the water-soluble divalent tin compound are preferably such
that the copper:tin ratio (metal component molar ratio) is 1:0.1
to 0.6, and more preferably such that the copper:tin ratio (metal
component molar ratio) is 1:0.1 to 0.3.
[0017]
A significant feature of the present invention is that
a sulfur-containing compound represented by formula (1):
R-(CH2)I-S-(CS2)7,-S-(CH2)n-R (1),
wherein R is H, OH, or SO3Na, and 1, m, and n are each
independently an integer of 0 to 3
is used as a complexing agent. Specific examples of sulfur-
containing compounds represented by formula (1) include
methanedithiol, 1,2-ethanedithiol, 1,3-propanedithiol, 3,6-
dithia-1,8-octanediol, bis-(sodium sulfopropy1)-disulfide, and
the like. Among these compounds, for example, 3,6-dithia-1,8-
octanediol and bis-(sodium sulfopropy1)-disulfide, both of which
have little odor, are preferable from the viewpoint of the work
environment, and 3,6-dithia-1,8-octanediol is more preferable.
These sulfur-containing compounds can generally be used singly,
or in a combination of two or more. The concentration of the
complexing agent is, for example, about 5 to 500 g/L, and
preferably about 80 to 320 g/L.
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[0018]
In the present invention, a hydroxyl group-containing
aromatic compound is used. Examples of hydroxyl group-containing
aromatic compounds include compounds in which a benzene ring or a
furan ring is substituted with one or more hydroxyl groups.
Compounds having a benzene ring are preferable from the viewpoint
of the work environment and solution stability. Specific examples
of hydroxyl group-containing aromatic compounds include phenol,
catechol, hydroquinone, resorcinol, pyrogallol, p-cresolsulfonic
acid, ascorbic acid, erythorbic acid; alkali metal salts thereof;
and the like. Examples of alkali metals include sodium, potassium,
and the like. Preferred hydroxyl group-containing aromatic
compounds are phenol, catechol, hydroquinone, resorcinol,
pyrogallol, p-cresolsulfonic acid, sodium ascorbate, and sodium
erythorbate. These hydroxyl group-containing aromatic compounds
are considered to have the action of reducing divalent copper
ions (Ce-) to monovalent copper ions (Cull, and are considered to
aid copper ions and the complexing agent in forming a complex.
These hydroxyl group-containing aromatic compounds can generally
be used singly, or in a combination of two or more. The
concentration of the hydroxyl group-containing aromatic compound
is, for example, about 1 to 50 g/L, and preferably about 5 to 30
g/L.
[0019]
The amounts of the complexing agent and the hydroxyl
group-containing aromatic compound are such that relative to 1
mol/L of copper, the amount of the complexing agent is preferably
2 mol/L or more, and the amount of the hydroxyl group-containing
aromatic compound is preferably 1 mol/L or more.
[0020]
Examples of acids constituting the base of the copper-
tin alloy plating bath include a wide variety of known organic
acids and inorganic acids. Specific examples of organic acids
include methanesulfonic acid, ethanesulfonic acid, 2-
propanolsulfonic acid, 2-sulfoacetic acid, 2-sulfopropionic acid,
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3-sulfopropionic acid, sulfosuccinic acid, sulfomethylsuccinic
acid, sulfofumaric acid, sulfomaleic acid, 2-sulfobenzoic acid,
3-sulfobenzoic acid, 4-sulfobenzoic acid, 5-sulfosalicylic acid,
4-sulfophthalic acid, 5-sulfoisophthalic acid, 2-
sulfoterephthalic acid, phenolsulfonic acid, and the like.
Specific examples of inorganic acids include sulfuric acid,
hydrochloric acid, sulfamic acid, and the like. Among these,
sulfuric acid, methanesulfonic acid, sulfosuccinic acid, and the
like are preferable. These acids can generally be used singly, or
in a combination of two or more. The concentration of the acid is
about 10 to 400 g/L, and preferably about 150 to 200 g/L.
[0021]
The copper-tin alloy plating bath is generally in a
weakly acidic to strongly acidic pH range. More specifically, the
pH of the solution of the plating bath is adjusted to 4.5 or less.
An overly high pH is not preferable because if the pH is overly
high, the obtained plating film will have insufficient smoothness.
Examples of usable pH adjusting agents include various acids,
such as hydrochloric acid and sulfuric acid; various bases, such
as ammonium hydroxide, sodium hydroxide, and potassium hydroxide;
and the like. In addition, a pH buffer may be added to reduce
variation in the pH of the plating bath. As the pH buffer, a
known pH buffer can be used. Examples of pH buffers include
sodium or potassium acetate, sodium, potassium, or ammonium
borate, sodium or potassium formate, sodium or potassium tartrate,
sodium, potassium, or ammonium dihydrogen phosphate, and the like.
These pH adjusting agents and pH buffers can generally be used
singly, or in a combination of two or more.
[0022]
The plating bath may contain additives, such as high
molecular compounds, surfactants, and levelers, if necessary.
[0023]
Examples of high molecular compounds include
polyethylene glycol and the like.
[0024]
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Examples of usable surfactants include known nonionic
surfactants, cationic surfactants, anionic surfactants, and
amphoteric surfactants. These surfactants can be used singly, or
in a combination of two or more. It is preferable that at least
one nonionic surfactant be contained.
[0025]
Examples of nonionic surfactants include
polyoxyalkylene alkyl ethers, polyoxyalkylene phenyl ethers,
polyoxyalkylene naphthyl ethers, polyoxyalkylene alkyl esters,
polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene
sorbit fatty acid esters, polyethylene glycol fatty acid esters,
polyoxyalkylene glycerin fatty acid esters, polyoxyalkylene
alkylamines, and the like. Among these, polyoxyalkylene
alkylamines are preferable, and polyoxyethylene alkylamines are
more preferable. Examples of cationic surfactants include tetra-
lower-alkylammonium halides, alkyltrimethylammonium halides,
alkylamine hydrochlorides, alkylamine oleates,
alkylaminoethylglycines, and the like. Examples of anionic
surfactants include alkyl-(3-naphthalenesulfonic acids, fatty acid
soap-based surfactants, alkyl sulfonic acid salts, alkyl sulfuric
acid ester salts, polyoxyethylene alkylphenol ether sulfuric acid
ester salts, and the like. Examples of amphoteric surfactants
include 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium
betaines, dimethylalkylbetaines, sulfobetaines, N-alkyl--
aminopropionic acids, and the like.
[0026]
When a high molecular compound or a surfactant is added
to the plating bath, the concentration of the high molecular
compound or the surfactant can be in the range of about 0.01 to
100 g/L, and preferably about 0.1 to 40 g/L.
[0027]
Levelers are additives that improve smoothness and
brightness. Examples of usable levelers include ketone compounds
and aldehyde compounds. As ketone compounds, a wide variety of
known aromatic ketones and aliphatic ketones can be used.
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Examples of aromatic ketones include acetophenone, benzophenone,
benzalacetone, and the like. Examples of aliphatic ketones
include acetone, diethyl ketone, and the like. As aldehyde
compounds, a wide variety of known aromatic aldehydes and
aliphatic aldehydes can be used. Examples of aromatic aldehydes
include cinnamaldehyde, a-methylcinnamaldehyde, a-
amylcinnamaldehyde, a-hexylcinnamaldehyde, cuminaldehyde,
benzaldehyde, anisaldehyde, and the like. Examples of aliphatic
aldehydes include formaldehyde, acetaldehyde, propionaldehyde,
and the like. Among these, aromatic ketones and aromatic
aldehydes are preferable. These levelers can be used singly, or
in a combination of two or more.
[0028]
When a leveler is added to the plating bath, the
concentration of the leveler can be in the range of about 0.01 to
30 g/L, and preferably about 0.01 to 10 g/L.
[0029]
As additives, a surfactant and a leveler are preferably
used in combination. A combined use of a surfactant and a leveler
can expand the current-density region in which a bright plating
film is obtained. This enables a plating film obtained from the
plating bath of the present invention to have more excellent
smoothness and higher brightness. As a combination of a
surfactant and a leveler, a combination of a nonionic surfactant,
and an aromatic ketone or an aromatic aldehyde is preferable. The
nonionic surfactant is preferably a polyoxyethylene alkylamine. A
plating film having excellent bright appearance can be obtained
by further adding a nonionic surfactant, and an aromatic ketone
or an aromatic aldehyde to the plating bath.
[0030]
When a surfactant and a leveler are used in combination,
the concentration of the surfactant is preferably about 0.1 to 40
g/L, the concentration of the leveler is preferably about 0.01 to
10 g/L, and the surfactant:leveler ratio is preferably about 1:1
to 100:1.
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[0031]
Additives other than the additives mentioned above,
such as stress-reducing agents, conductive auxiliary agents,
antifoaming agents, and brighteners, may be suitably selected and
added to the plating bath, if necessary.
[0032]
Examples of stress-reducing agents include
naphtholsulfonic acid, saccharin, sodium 1,5-
naphthalenedisulfonate, and the like. These can be used singly,
or in a combination of two or more. Examples of conductive
auxiliary agents include hydrochloric acid, sulfuric acid, acetic
acid, nitric acid, sulfamic acid, pyrophosphoric acid, boric acid,
and like acids; ammonium salts, sodium salts, potassium salts,
and organic amine salts thereof; and the like. These can be used
singly, or in a combination of two or more. As antifoaming agents
and brighteners, commercially available antifoaming agents and
brighteners for copper plating, tin plating, copper-tin alloy
plating, and general plating can be suitably selected and used.
[0033]
The bath preparation method for the plating bath of the
present invention is not particularly limited. For example, the
target plating solution can be obtained by dissolving a water-
soluble copper compound and a water-soluble divalent tin compound
in an aqueous solution in which an acid such as sulfuric acid is
dissolved; adding a complexing agent and a reducing agent
thereto; adding, if necessary, other additives thereto; and,
finally, adjusting the pH to a predetermined pH.
[0034]
There is no particular limitation on the plating method
in which the plating bath of the present invention is used. The
plating bath of the present invention can be used in known
plating methods, and can also be applied to barrel plating, in
which the variation in current density is large.
[0035]
When the bath temperature during plating is low,
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throwing power increases, but the film formation speed tends to
decrease. Conversely, when the bath temperature is high, the film
formation speed increases, but throwing power onto low-current-
density regions tends to decrease. Taking this point into
consideration, an appropriate bath temperature can be detelmined.
The bath temperature is preferably in the range of about 5 to 40 C.
[0036]
The cathode current density can also be appropriately
detelmined according to the plating solution used, type of object
to be plated, etc. A cathode current density of about 0.1 to 3
A/dm2 is preferable.
[0037]
The anode may be any known anode that can be used for
copper-tin alloy plating, such as a soluble anode (e.g., a tin
anode, a phosphorus-containing copper anode, an oxygen-free
copper anode, or a copper-tin alloy anode) or an insoluble anode
(e.g., a stainless anode, a carbon anode, a lead anode, a lead-
tin alloy anode, a lead-antimony alloy anode, a platinum anode, a
titanium anode, a titanium-platinum anode, or an oxide coated
anode, such as an iridium-oxide-coated titanium electrode). The
cathode is an object to be plated that is described below. Thus,
it can be said that the method for copper-tin alloy plating of
the present invention is a method in which electrolysis is
performed using an object to be plated as a cathode in the
copper-tin alloy plating bath described above.
[0038]
The copper-tin alloy plating film described above is
formed on the surface of an article to be plated by the above
plating method. The alloy composition of the obtained film is
such that the Cu:Sn weight ratio is 95:5 to 5:95, and the alloy
composition can be easily changed by varying the Cu concentration
or the Sn concentration in the plating solution. The article to
be plated is not particularly limited as long as the surface is
conductive and smooth. Examples of such articles include home
appliances, faucet fittings, sundry articles, decorations,
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clothing accessories, and the like.
[0039]
The copper-tin alloy plating bath of the present
invention can be suitably used for plating for clothing
accessories or decorations; and plating for, for example,
electronic or electric components. However, this does not limit
applications to other purposes.
Examples
[0040]
The present invention is described below in more detail
with reference to Examples and Comparative Examples.
[0041]
Plating treatment was performed using plating baths
having the compositions shown in Tables 1 to 6 below under the
following conditions to individually form plating films on
objects to be plated.
Object to be plated: iron plate (5 cm x 5 cm)
Plating method:
Anode: pure tin plate (10 cm x 5 cm, two plates)
Amount of solution: 1.5 L (a plastic container having a
size of 14 cm x 8 cm x 18 cm was
used)
Stirring: shaking with a cathode rocker
Plating conditions:
Temperature: 18 to 20 C
Current density: 1 A/dm2
Electrolytic time: 25 minutes
[0042]
Tables 1 to 6 show the state of each plating solution,
and the properties of each of the plating films formed as
described above. The evaluation methods for the properties are as
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follows.
Solution state: The state of each solution was visually confirmed.
Solution stability: After being allowed to stand for 24 hours,
each plating solution was visually confilmed.
Plating appearance and occurrence of cracking: Plating appearance
and occurrence of cracking were observed with a digital
microscope.
Cu:Sn ratio: The Cu:Sn ratio was evaluated with a fluorescent X-
ray film thickness measurement apparatus.
[0043]
In addition, in the plating baths of Example 3 and
Comparative Examples 11 and 12, plating treatment was performed
at current densities of 0.01, 0.1, 0.5, 1, 2, and 3 A/dm2, and the
copper content of the formed plating films was determined. Fig. 1
shows the results.
CA 02957587 2017-02-07
¨15-
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14,
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Table 2
Ex ample 10 Ex ample 11 Example 12 Ex ample 13 Example 14
Examo 15 _ E5114513 16 Conparalve Example 6 , Comparaem Exaaple 2
Comparam Exerrple 8 Comaarative Exanple 9 , Comparatie Example 10,
98% sulfuric acid (g/L) 185 185 185 185 , 155 185 185
, 185 , 185 185 185 185
Copper sultale penthydrate (g/L) 60 60 60 60 60 80 80
, 60 so 80 ¨ so ao
. . .
10 , . _
Stannous suit% (g/L) 10 10 10 10 10 10 10
10 , 10 10 .
, , , t
.
3,6-d811a-1,8-octanedul (g/L) 120 120 120 120 120 120 120
120 120 120 120 120
Hydroqu 15 inone (g/L) ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ ¨ ¨ ¨
,
Resorcinol (g/L) ¨ 15 ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ ¨ ¨
Phenol (g/L) ¨ ¨ 15 ¨ ¨ ¨ ¨ ¨
¨ ¨ ¨
p-cresolsulbnic acid (g/L) ¨ ¨ ¨ 30 ¨ ¨ ¨
¨ ¨ ¨ ¨ ¨
Pyrogalot (g/L) ¨ ¨ ¨ ¨ 20
' Sodium ascorbat (g/L) ¨ ¨ ¨ ¨ 30 ¨ ¨
¨ ¨ ¨ ¨
Sodium eryborbals (g/L) ¨ ¨ ¨ ¨ ¨ ¨ 30 ¨
¨ ¨ ¨ ¨ 9
Sodb - m hypophosphit (OIL) ¨ ¨ ¨ ¨ ¨
¨ 15 ¨ ¨ ¨ - o
Sodkim sutit (q1) ¨ ¨ ¨ ¨ ¨ ¨ ¨ 20
¨ ¨ k,
.
o
Sodium hydrogen suite (g/L) ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ ¨ 20 ¨ vi
.
..3
Ammonium sults (g1L) ¨ ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ ¨ 20 uti
co Sodium tibsultat (g/L) ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ ¨ ¨ 25 -4
1 k,
P111 0.1 or less 0.1 or less 0.1 or less 0.1 or less
0.1 or less 0.1 01 1688 0.1 or less 0.1 or less , 0.2 or less
01 Of 1685 0.1 or less 0.1 or less I--1
Solution stit No prectilats No precipitats No preaptes No
precipitles No precipitates No preciptats No pre/4)631as No
precipitts Bad odor Bad odor Bad odor Predpitts 01% tzt
Soluton stbility Good Good Good Good Good Good Good
Poor Good Good Good Poor P,
Gray Gray Gray Mit Black V'tit Gray
Gray i
PlaIng appearance (1 A/dm2)
Dull Dull Dull Da N Dull Dull Dull
Dull o
...t
=
Presence or absence &cracks No cracks No cracks No cracks
No cracks No cracks No cracks No cracks Cracks Plaing was not
perbrmed.
Cu:Sn ratio (wt%) 62:38 61:09 65:35 5941 6139 _ 62:38
63:37 62:38
,
,
..
=
,
,
,
,
i
,
=
,
=
:
,
[0046]
Table 3
Examte 17 Example 18 Example 19 Example 20 Example 21
Ex-4e 22 Example 23 Example 24 Example 25 Exarrple 26 Example
27 Exarrple 28
98% SUMA acid (A) 185 185 165 185 185 185 185 185
185 185 185 185
Copper sulfat pentahydrat (g/L) 60 60 60 60 60 60 60
60 60 60 60 60
Stannous sulfab (g/L) 10 10 10 10 10 10 10 10
10 10 10 10
3,6-4i850-1,8-octanediol (giL) 120 120 120 120 120 120 ,
120 120 120 120 120 120
,P_ohyhAyie_talene alkylarrine (a/L) 10 ¨ ¨ ¨ ¨ ¨
¨ ¨ ¨ ¨ ¨ ¨
Polyetylene glycol (g/L) ¨ 5 ¨ ¨ ¨ ¨ ¨
¨ ¨ ¨
Polyoxyalkylene phenyl ether (g/L) ¨ ¨ 20 ¨ ¨
¨ ¨ ¨ ¨ ¨
,
Polyoxy elkylene naphtyl ether (g/L) ¨ ¨ ¨ 10 ¨ ¨
¨ ¨ ¨ ¨ ¨ ¨
Tera-loweralkylammonium beide (cirL) -- ¨ 0.5 ¨ ¨ ¨
Alkylatane hydrochbride (g/L) ¨ ¨ ¨ ¨ ¨ 1 ¨
¨ ¨ ¨ ¨
Alkylarrinoethylglycine (g/L) ¨ ¨ ¨ ¨ ¨ ¨ 1
¨ ¨ ¨ ¨ ¨
g
,
4liky1-6-naphhalenesulbnic acid (9/Li) i ¨ ¨ ¨ ¨ ¨ ¨
¨ 30 ¨ ¨ ¨ ¨ o
Fatty acid soap-based surfacels (gIL) ¨ ¨ ¨ ¨ ¨ ¨
¨ ¨ 10 ¨ ¨ np
ko
Phenol ether sulfuric used ester sett (gIL) ¨ ¨ ¨ ¨ ¨
¨ ¨ ¨ ¨ 5 - - ,..
,
Sulkthelaine (g/L) ¨ ¨ ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ 5 ¨ ul
op
Dimethylalkylbetaine (gIL) ¨ ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ ¨ 10 -4
pH 0.1 or less 0.1 or less 0.1 or less , 0101
less 0101 less 0.1 01 855 0.1 or less 0.1 or less , 0.1 or
less 0.1 or less 0.1 or less 0.1 or less I H
o
Solukon stale No preciplats No precipitats No precipitats
No precifklats No predpitales No precipitats No precipitates No
precipartes , No presipitileS No preciptiPs No precipitate No
precipitats
1
Solukon stablity Good G000 Good Good Good Good Good
Good Good Good Good Good 1
Pp
Mb IAAlb Mila Mit Mit WA 75848
Mile mile mt MP IThile i
Plating appearance (1 Arcere)
o
Serri-bright Seed-bright Semhbright Serri-bright Semi-
bright Sera-bright _ Serra-bright õ Sere-bright Semi-bright Semi-
bright , Sera-bright Semi-bright ....]
Presence or absence of cracks No cradre No cracks No cracks No
cracks No cracks No cracks No cracks No cracks No cracks _
No cracks No cracks No cracks
Cu:Sn ratio (wl%) 61:39 58:42 63:37 59:41 60:40 57:43
63:37 53:37 58:42 59:41 56:44 63:37 -
=
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,
=
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=
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-
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,'.
= =
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=
T.,
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,I.
4
[0047]
Table 4
.
Example 29 Example 30 Example 31 Example 32 Example
33 , Example 34 Example 35 Example 36 Example 37 Example 38
Exempt 39
98% sultrio acid (g/L) 185 185 , 185 185 185 185
185 185 185 185 185
. . . , .
.
Copper sultat pentahydrat (q/L) 60 60 60 60 60 60
60 60 60 60 60
Stannous sulfat (g/L) 10 10 10 10 10 10 10
10 10 10 10
3,6-dibia-1,8-octenedipl OM 120 120 120 120 120 120 120
120 120 120 125
Benzalacetne (g/L) 1 - - - -
- -
,
Cinnarraldehyde (g/L) - 1 - ' , -
- - .. -
a-methylcinnarnaklehyde (gIL) - - 3 -
- - - - .
a-hexylcinnamaldehyde (g/L) - - 5 -
- - -
o-amylcinnamaldehyde (gIL) - - - 5 -
- - -
g
Currinaldehyde (g/L) - - - 1 - -
- -
Benzaldehyde (g/L) - - - - 1 -
- 0
I,
Anisaldehyde (g/L) - - - - - 3
- - - - ,0
in ..i
Propionakiehyde (gIL) - - - - - -
- 3 - - ix
co
Acetaldehyde (gIL) - - - - - - -
- 0.5 - -..i
I n.,
Formaldehyde (g/L) - - - - - - - -
- - 0.5 0 , 1¨'
pH al or less 0.1 or less 0.1 or less 0.1 or less
_ 0 1 or less 0.1 or less 0.1 or less 0.1 or less 0.1
or less 0.1 or less 0.1 or less CO '73
Solution stale , No precipitates No precipitats No precipitates
No precipitates No precipitats No precipitates No
precipitates No predpitalas No precipitates No precipitets No
precipitates 2
Solution stabil* Good Good Good Poor Poor Good Good
Good Good Good Good o1
Mite Wick Mit Wick Wick - Mile Write
Mile Mit Wilk! Write .-.1
Platng appearance (1 Alani)
Semi-bright Semi-bright Serri-bright Semi-bright
Semi-brht _ Serri-bright Serri-bright Sem-bright Semi-bright Senti-
bright Senl-bright
Presence or absence of cracks No cracks No cracks No cracks
No cracks No cracks No cracks No cracks No cracks No cracks
No cracks No cracks
_
Cu:Sn rata (wt%) 57:43 58:42 60:40 58:42 57:43 61:39
58:42 61:39 59:41 63:37 64:36
=
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[0048]
Table 5
Exanple 40 Example 41 Example 42 Example 43 Example
44 Example 45 Example 46 Example 47 Example 48 Example 49
Example 50
98% sulfuric acid (g/L) 185 185 185 185 185 185 185
185 185 185 185 ,
Copper sulfat penahydrab (g/L) 60 60 60 60 60 60
__________ 60 60 60 60 60
Stannous suckle (9/L) 10 10 10 10 10 10 10 10
10 10 10
3,6-dibia-1,8-octenediol (91L) 120 120 120 120 120 120
120 120 120 120 120
Polyoxyebylene alkylamine (qIL) 10 10 10 10 10 10
10 10 10 10 10 .
Benzalacebne (g/L) 1 ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ ¨
.
.
Cinnamaldehyde (g/L) ¨ 1 ¨ ¨ ¨ ¨ ¨ ¨
¨
ci-mebyloinnamaldehyde (g/L) ¨ ¨ 3 ¨ ¨ ¨
¨ ¨ .
a-hexylcinnamaldehyde (g1L) ¨ ¨ ¨ 5 ¨
- ¨ ¨ .
a-amylonnarralclehyde (g/L) ¨ ¨ ¨ ¨
¨ ¨ g =
Currinaldehyde (g/L) ¨ ¨ ¨ ¨ ¨ 1 ¨ ¨ ¨
¨ ¨
2
Benzaldehyde (g/L) ¨ ¨ ¨ ¨ ¨ 1 ¨ ¨
¨ ¨ so
u,
Anisaldehyde (g/L) ¨ ¨ ¨ ¨ ¨ ¨ 3 ¨
¨ ¨ ...3
.
u)
Propionaldehyde (g/L) ¨ ¨ ¨ ¨ ¨ ¨ ¨ 3
¨ ¨ co
. .
-..3
Acetaldehyde (d/L) ¨ ¨ ¨ ¨ ¨ ¨ ¨ ¨
9.5 ¨ I Iv
,z)
Formaldehyde (g/L) ¨ ¨ ¨ ¨ ¨ ¨ ¨ ¨
¨ 0.5 I¨i 1-
. .
..)
pH 0.1 or less 0.1 or less 0.1 or less 91 or less
0.1 or less 01 or less 0.1 or less , 0.1 or less 0.1 or less
0.1 or less 0.1 or less L.0 1
Solution stab No predpitabs Sc precipiabs No precipitates No
precipitabs _ No precipilabs , No precipitales No precipitates
No_precipitabs No precipitabs No precipiteles No dredge:its 2
O
Solulion stabile/ Good Good Good Poor , Poor Good Good
Good Good Good Good .-.1 .
Mile VVnib Mie ¨ Mae Mile Mile Mib
Mile Mb Mit Mite .
Plating appearance (1 A/drn2) Bright Bright Bright Bright ,
Bright Bright Bright Bright Bright Bright Bright
Presence or absence of cracks No cracks No cracks No cracks No
cracks No cracks No cracks No cracks No cracks No cracks No
cracks No cracks
¨
Cu:Sn rain (wt%) 5941 59:42 61:39 57:43 6238 5842
58:42 62:38 59:41 59:41 62:38
¨
.
,
=
,
,
,
,
,
,
1
,
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CA 02957587 2017-02-07
-20-
[0049]
Table 6
Comparative Comparative
Example 11 Example 12
Potassium pyrophosphate (g/L) 200
Copper pyrophosphate (g/L) 20
Stannous sulfate (g/L) 10
Organic sulfonic acid (g/L) 100
Stannous sulfate (g/L) 36
Copper sulfate pentahydrate (g/L) 12
Brightener Appropriate Appropriate
amount amount
pH 7 to 8 0.5
Solution state No precipitates No
precipitates
Solution stability Good Poor
Plating appearance (1 A/dm) White White
Presence or absence of cracks Cracks No cracks
Cu:Sn ratio (wt%) 58:42 53:47
[0050]
The results of Tables 1 to 5 reveal that no
precipitates were formed in the plating baths of Examples 1 to
50; that the solution state was stable, especially in the plating
baths of Examples 1 to 5, 10 to 31, 34 to 42, and 45 to 50; and
that crack-free plating films were obtained by plating. As is
clear from the results of Examples 1 to 5 in Table 1, a copper-
tin alloy plating film having any ratio can be obtained by
adjusting the metal concentration in the plating solution. The
results of Tables 3 to 5 show that adding a surfactant or a
leveler to the plating solution improves brightness of a plating
appearance, and that a plating appearance having excellent
brightness can be obtained by adding both a surfactant and a
leveler to the plating solution. In addition, Fig. 1 shows that
in the plating bath of the present invention, the current density
has a small influence on the alloy ratio as compared with the
case of a hitherto known acidic bath (Comparative Example 12).
