AQUEOUS ACIDIC COPPER PLATING BATH WITH CHLORIDE IONS AND SULFUR COMPOUNDS

BAIN DE CUIVRAGE AQUEUX ACIDE A IONS DE CHLORE ET COMPOSES DE SOUFRE

English Abstract

NOVEL PROCESSES AND COMPOSITIONS
Abstract of the Disclosure - In accordance with
certain of its aspects, this invention relates to novel
compositions and to a process for electrodepositing bright,
strongly leveled, ductile copper from an aqueous acidic
copper plating bath containing chloride ions and at least
one member independently selected from each of the
following groups:
(A) a polysulfide compound of the formula
<IMG> ;
(B) a heterocyclic sulfur compound
containing the grouping
<IMG>
and/or tautomers thereof,
where the nitrogen atom and the two
carbon atoms are part of a heterocyclic
ring; and
(C) a polyether containing at least 5 ether
oxygen atoms per molecule;
wherein R is independently a divalent aliphatic or aromatic
non-heterocyclic group of 1 - 10 carbon atoms; R' is hydrogen,
a metal cation, a monovalent aliphatic or aromatic group of
( i )

1 - 20 carbon atoms, or the groups -R-SO3M or -R-(S)q-RSO3M
wherein q is an integer 2-5; M is a cation; Z is 0 or 1;
R" is hydrogen, a metal ion or one of the groups
<IMG> , <IMG> , <IMG>
where R"' is hydrogen, an alkyl group of 1 - 6 carbon atoms,
aryl, alkaryl or aralkyl group.
( ii )

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for electrodepositing bright, strongly levelled, ductile
copper, which comprises passing a current through an aqueous acidic copper
plating bath containing chloride ions in a concentration of 0.5 to 500 mg
and at least one member independently selected from each of the following
groups: (A) a polysulfide compound of the formula
<IMG> ;
(B) a heterocyclic sulfur compound containing the grouping
<IMG>
and/or tautomers thereof, where the nitrogen atom and the two
carbon atoms are part of a heterocyclic ring; and
(C) a polyether containing at least 5 ether oxygen atoms per
molecule; wherein R is independently a divalent aliphatic or aromatic non-
heterocyclic group of 1 - 10 carbon atoms; R' is hydrogen, a metal cation,
a monovalent aliphatic or aromatic group of 1 - 20 carbon atoms, or the
groups -R-SO3M or -R-(S)q-RSO3M wherein q is an integer 2-5; M is a cation;
Z is 0 or 1; R: is hydrogen, a metal ion or one of the groups:
<IMG> , <IMG> , <IMG>
wherein R"' is hydrogen, an alkyl group of 1 - 6 carbon atoms, aryl, alkaryl
or aralkyl group, in which the additive is present in an amount sufficient to
obtain a cathodic electro-deposit of bright, strongly levelled, ductile
copper, and in which the process is controlled to obtain a cathodic electro-
deposit of bright, strongly levelled, ductile copper.
2. The process of claim 1 wherein said heterocyclic sulfur compound
is 2-mercaptopyridine (2-pyridinethiol).
36

3. The process of claim 1 wherein said hetorocyclic sulfur compound
is 2-S-pyridyl isothiouronium chloride.
4. The process of claim 1 wherein said heterocyclic sulfur compound
is 2-mercaptopyridine-n-oxide (1-hydroxy-2-pyridinethione).
5. The process of claim 1 wherein said heterocyclic sulfur compound
is 2-S-pyridyl isothiouronium chloride N-oxide.
6. Tho process of claim 1 wherein said heterocyclic sulfur compound
is 2-mercapto-4-methylpyridine.
7. The process of claim 1 wherein said heterocyclic sulfur compound
is 4-methyl-2-S-pyridyl isothiouronium chloride.
8. The process of claim 1 wherein said heterocyclic sulfur compound
is 2-mercapto-4-methylpyridine-N-oxide.
9. The process of claim 1 wherein said heterocyclic sulfur compound
is 4-methyl-2-S-pyridyl isothiouronium chloride N-oxide.
37

10. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2-mercapto-6-methylpyridine.
11. The process of Claim 1 wherein said heterocyclic
sulfur compound is 6-methyl-2-S-pyridyl isothiouronium chloride.
12. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2-mercapto-6-methyl pyridine-N-oxide.
13. The process of Claim 1 wherein said heterocyclic
sulfur compound is 6-methyl-2-S-pyridyl isothiouronium chloride
N-oxide.
14. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2-mercaptoquinoline.
15. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2-S-quinolyl isothiouronium chloride.
16. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2-mercaptoquinoline N-oxide.
17. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2-S-quinolyl isothiouronium chloride N-oxide.
18. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2-mercapto-6-hydroxy pyridine.
19. The process of Claim 1 wherein said heterocyclic
sulfur compound is 6-hydroxy-2-S-pyridyl isothiouronium chloride.
20. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2,6-dimercapto pyridine.
- 38 -

21. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2,6-SS-pyridyl bis-isothiouronium chloride.
22. The process of Claim 1 wherein said heterocyclic
sulfur compound is thiocaprolactam (2-thioxohexamethyleneimine).
23. The process of Claim 1 wherein said heterocyclic
sulfur compound is 2-S-pyridyl-N-diethyl dithiocarbamate.
24. An aqueous acidic copper plating bath
containing chloride ions and at least one member independently
selected from each of the following groups:
(A) a polysulfide compound of the formula
<IMG>;
(B) a heterocyclic sulfur compound
containing the grouping
<IMG>
and/or tautomers thereof,
where the nitrogen atom and the two
carbon atoms are part of a heterocyclic
ring; and
(C) a polyether containing at least 5 ether
oxygen atoms per molecule;
wherein R is independently a divalent aliphatic or
aromatic non-heterocyclic group of 1 - 10 carbon atoms;
- 39 -

R' is hydrogen, a metal cation, a monovalent aliphatic or
aromatic group of 1 - 20 atoms, or the groups
-R-SO3M or -R-(S)q-RSO3M wherein q is an integer 2-5;
M is a cation; Z is 0 or 1; R" is hydrogen, a metal ion
or one of the groupd:
<IMG> , <IMG> , <IMG>
where R''' is hydrogen, an alkyl group of 1 - 6 carbon atoms,
aryl, alkaryl or aralkyl group.
25. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercaptopyridine (2-pyridinethiol).
26. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-S-pyridyl isothiouronium chloride.
27 An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercaptopyridine-n-oxide (1-hydroxy-2-pyridinethione).
28. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-S-pyridyl isothiouronium chloride N-oxide.
29. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercapto-4-methylpyridine.
- 40 -

30. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 4-methyl-2-S-pyridyl isothiouronium chloride.
31. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercapto-4-methylpyridine-N-oxide.
32. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 4-methyl-2-S-pyridyl isothiouronium chloride N-oxide.
33. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercapto-6-methylpyridine.
34. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 6-methyl-2-S-pyridyl isothiouronium chloride.
35. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercapto-6-methyl pyridine-N-oxide.
36. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 6-methyl-2-S-pyridyL isothiouronium chloride N-oxide.
37. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercaptoquinoline.
- 41 -

38. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-S-quinolyl isothiouronium chloride.
39. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercaptoquinoline N-oxide.
40. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-S-quinolyl isothiouronium chloride N-oxide.
41. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-mercapto-6-hydroxy pyridine.
42. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
6-hydroxy-2-S-pyridyl isothiouronium chloride.
43. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2,6-dimercapto pyridine.
44. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2,6-SS-pyridyl bis-isothiouronium chloride.
45. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is thiocaprolactam (2-thioxohexamethyleneimine).
- 42 -

46. An aqueous acidic copper plating bath as
claimed in Claim 24 wherein the heterocyclic sulfur compound
is 2-S-pyridyl-N-diethyl dithiocarbamate.
- 43 -

Description

l03s~a6
This invention relates to novel processes and
compositions for the electrodeposition of copper from aqueous
acidic baths. More particularly, this invention relates to
certain bath compositions containing specified combinations
of chemical ingredients and to the use of such compositions
to obtain bright, ductile, strongly leveled copper electro-
deposits.
In accordance with certain of its aspects, this
invention relates to novel compositions and to a process for
electrodepositing bright, strongly leveled, ductile copper
` from an aqueous acidic copper plating bath containing chloride
: ions in a concentration of 0.5 to 500 mg/l and at least one
; member from each of the following groups:
(A) a polysulfide compound of the formula
R' (S)n R-so3M;
}~' ' '
, .,

(B) a heterocyclic sulfur compound containing the
grouping
- N = C - C
S
( )Z ''
and/or tautomers thereof, where the nitrogen
atom and the two carbon atoms are part of a
heterocyclic ring; and
tC) a polyether containing at least 5 ether oxygen
atoms per molecule; wherein R is independently a divalent ali-
phatic or aromatic non-heterocyclic group of 1 - 10 carbon atoms;
R' is hydrogen, a metal cation, a monovalent aliphatic or aromatic
group of 1 - 20 carbon atoms, or the groups -R-S03M or -R-(S)q-RS03M
wherein q is an integer 2-5; M is a cation; Z is 0 or 1; R" is
hydrogen, a metal ion or one of the groups
C ~ - C~ - C - N(R"')
\ N(R~)2, ~ R~ , S 2 , .
where R"' is hydrogen, an alkyl group of 1 - 6 carbon atoms, aryl,
alkaryl or aralkyl group, in which the additive is present in an
amount sufficient to obtain a cathodic electro-deposit of bright,
strongly levelled, ductile copper, and in which the process is con-
tinued for a time period sufficient to obtain a cathodic electro-
deposit of bright, strongly levelled, ductile copper.

103832~
The combination of these three additives in a
chloride-containing copper plating bath gives unexpected
beneficial effects over the use of each additive aLone in
a chloride-containing copper plating bath.
Simultaneous use of at least one member from
each of the three groups of additives gives bright copper
deposits over a wide current density range with strong
leveling properties. As used herein, the term "leveled"
denotes a surface which is smoother than its su~strate.
The high degree and rate of leveling leads to an important
economy in finishing costs and materials. The improved
low current density brightness (i.e. the widening of the
bright current density range) is important if strongly
profiled objects are to ~e plated. The polysulfide
sulfonates, as defined herein, have been found to be
much more effective when employed according to the
invention than the corresponding monosulfides.
When used alone these classes of additives
(denoted A, B, and C herein) may be found to be deficient
in one or more aspects. Thus, the copper deposits obtained
may not be bright, smooth, and may not exhibit adequate
leveling properties over a sufficient current density
range. Combinations utilizing two of the additives may
give faixly bright copper deposits, but the current density
range of brightness may be limited and/or the rate of
leveling (decrease of surface roughness) may be low. Other
double combinations of additives may give striated deposits
and limited bright current density ranges.

_. !
~ 10383,Z6
The novel compositions of the invention may be
employed in combination with aqueous acidic copper plating
baths. Typical aqueous acidic copper plating baths which
may be employed in combination with the novel additive
compositions (~, B, and C) of the invention include the
following:
T~BLE I
Sulfate Bath
~1) CUS04 5H20220 g/l)
H2S0410-110 g/l (preferably about
60 ~/1)
Cl5-150 mg/l (preferably about
20-80 mg/l)
Fluoborate Bath
(2) cu(BF4)2100-600 g/l (preferably about
224 g/l)
HBF41-60 g/l (preferably about
3.5 g/l)
H3B030-30 g/l (prefer)ablY about
Cl5-150 mg/l (preferably about
20-80 mg/l)
The basis metals which may be electroplated in
accordance with the process of this invention may include
ferrous metaLs, such as steel, iron, etc., bearinz a surface
layer of nickel or cyanide copper; zinc and its alloys
including zinc-base die-cast articLes bearing a surface layer
of cyanide copper or pyrophosphate copper; nickel, including
nickel alloys with other metals such as cobalt; aluminum,
including its alloys, after suitable pretrentment, etc.

' 1038326
After the deposition of the bright leveled
copper deposit of this invention, ~enerally a ~right nickel
deposit and a chromium deposit (which may be microporous
or microcracked) may be applied. The ~right acid copper
deposit of this invention contributes to the appearance
and performance of the composite coating because of its
very high rate of leveling, its excellent pore-filling
capacity, its high luster, good ductility and low
internal 6tress. It improves corrosion resistance and
permits economy in nickel use.
Because of its strong Leveling properties, its
very good performance at high current densities, and its
very good mechanical properties (especially good ductility
and low stress) the bright acid copper electrodeposit9 of
this invention may be used for industrial applications
such as electroforming, the plating of memory drums,
printing rolls, etc. The process gives very good results
also for the plating of non-conducting materials, such as
plas~ics, after the usual pretreatment.
The plating conditions for electrodeposition
from the aforementioned baths may, for example, include
temperatures of 10C. - 60C. (preferably 20C. - 40C.);
pH (electrometric) of less than about 2.5; and a cathode
current density of .1 - 50.0 amperes per square decimeter
(asd).
_ 5 _ I

1038326
Typical average current densities may be 2 - 20
asd for the sulfate bath and about 4 - 40 asd for the
fluoborate bath. Air agitation, volume agitation, or
mechanical agitation may incrèase the effective current
density ranges and enhance the uniformity of the copper
deposit.
In accordance with certain of its aspects, this
invention relates to noveP compositions and to a process
for electrodepositing bright, strongly leveled, ductile
copper from an aqueous acidic copper plating bath containing
chloride ions and at least one member independently selected
from each of the following groups:
(A) a polysulfide compound of the formula
R' ~ ) R-S03M;
(B) a heterocyclic sulfur compound
containing the grouping
-- ~ = C -- C --
t
(~ I
\OJz R"
and/or tautomers thereof,
. where the nitrogen atom and the two
carbon atom~ are part of a heterocyclic
. ring; and
.
(C) a polyether containing at least 5 ether
oxygen atoms per molecule;
wherein R is independently a divalent aliphaticlor
aromntic non-heterocyclic group of 1 - 10 carbon ~tom~;

1038326
R' is hydrogen, a metaL cation, a monovalent aliphatic or
aromatic group of 1 - 20 carbon atoms, or the groups
-R-S03M or -R-(S)q-RS03M wherein q is an integer 2-5;
M is a cation; Z is 0 or 1; R" is hydrogen, a metal ion
or one of the groups
4 NR"' ~ NR"'
- C - C - C - N(R"' )2
N(R"' )2 R"' , S
where R"' i8 hydrogen, an alkyl group of 1 - 6 carbon atoms,
aryl, alkaryl or aralkyl group.
Sulfide compounds wherein n is an integer 2 - 4
are preferred. R may be a divalent hydrocarbon group
(including such hydrocarbon groups containing inert
substituents such as hydroxyl, alkoxy, polyoxyalkylene,
halogen, etc.) of 1 - 10 carbon atoms such as an alkylene
group of 1 - 10 carbon atoms ~i.e. -CH2-, -CH2CH2-, -~CH2)3-,
-~CH2)~-, and, in general, -~CH2)p- wherein ~ is an integer
1 - 10. R may be a divalent non-heterocyclic group of
1 - 10 carbon atoms containing 1 - 3 oxygen, 1 - 3 ~ulfur,
or 1 - 3 nitrogen atoms (such as -CH2CH20CH2CHz-,
~CHzOCH2CH20-CH2-~ -CH2CH2-,
/=\ - /=\ /~\
-CH2 - ~ -CH2-, - ~ -, ~ -CHz-, - ~ -CH3,
-CHzCHOHCH2-, -CH2CH2-NHCHzCH2-, -CHzCHzSCH2CH2-, etc.).
In the compound R~ (S)n R-S03M (1),
R' may be a hydrocarbon radical preferably ~elected from
- 7

103832~;
the group consisting of alkyl, alkenyl, aLkynyl, cycloalkyl,
aralkyl, aryl, alkaryl, including such radicals when inertly
substituted. When R' is alkyl, it may typically be straight
chain alkyl or ~ranched alkyl, including methyl, ethyl,
n-propyl, isopropyl, n-butyL, isobutyl, sec-butyl, tert-butyl,
n-amyl, neopentyl, isoamyl, n-hexyl, isohexyl, heptyls,
octyls, decyls, dodecyls, etc. Preferred alkyl includes
lower alkyl, i.e. having less than about 8 carbon atoms,
i.e. octyls and lower. When R' is alkeny~ it may typically
be vinyl, allyl, methallyl, buten-l-yl, buten-2-yl,
butyn-3-yl, penten-l-yl, hexenyl, heptenyl, octenyl,
decenyl, dodecenyl, tetra-decenyl, octadecenyl, etc. When R'
is alkynyl, it may typically be ethynyl, propargyl, ~utynyl,
etc. When R' is cycloalkyl, it may typically be cyclopentyl,
cyclohexyl, cycloheptyl, cyclooctyl, etc. When R' is aralkyl,
it may typically be tolyl, xylyl, p-ethylphenyl, p-nonylphenyl,
etc. R' may be inertly substituted, e.g. may bear a non-
reactive su~stituent such as alkyl, aryl, cycloalkyl, aralkyl,
alkaryl, alkenyl, ether, etc.
Polysulfide compounds of the formula (A) may
typicalLy be prepared by the reaction of an alkali metal salt
of a hydropolysulfide and a sultone according to the reaction:
R~ _ ~S)nM ~ R\-/ o2 ~ R' (S~n _ R-S03M (1)
O
wherein R, R', M, and n are as previously defined.
~ _

I03B3a6
Specific illustrative reaction8 may include the
following reactions wherein all unsubstituted carbon atoms
are attached to hydrogen atom9:
~1> ~ -SSNa I CH~ - C~ -SSCHaCH~CH2SO~Na
CH2 0
(2) CH3 (CHz)7SSK ~ (CH2)2~cH~
~SO2 ~ CH3 (CH2)7SS (CH2 )4SO3K
CH2 0
(3) Na2S2 ~ 2 CH2--CH~
~SO2 ~ NaO3S ~CH2 )3SS (CH2 )3SO3Na
oOCH2--O
I~ONa
(4) ~-SSNa +2 . CH2 4 C8 ~ CO-CH2CH2CH2-SO3Na
CHi / O -SSCH2CH2CH2SO3Na
2 CH~ (CH2)3SO3H
-SSNaCH2- O / ~ -SSCH2CH2CH2SO3Na
Other preparative reactions which may be u9ed to
produce the 3ulfide compounds employed according to the
invention include the direct sulfonation of an organo
poly9ulfide (i.e. direct sulfonation of diphenyl disulfide,
ditolyl di9ulfide, etc. ) . The poLy9ulfide compound9 al~o

1038326
may be prepared by the reaction of epichlorohydrin and an
alkali metal bisulfite followed by reaction with a polrsulfide
~6uch as Na2S2, R'SNa, wherein R' i9 as previously defined).
Other preparative reactions may include the
following:
(a) SClz + 2NaS (CH2 )3 S03Na~NaO3 S (CH2 ) 3S -S -S - ~CH2 )3 S03Na
(b) S2Cl2 ~ 2NaS(CH2)3SO3Na~NaO3S(CH2)3S-S-S-S-(CH2)3SO3Na
(c) ClCH2CH2Cl + 2NaSS(CH2)3SO3Na ~
NaO3 S (CH2 )3 SSCH2 CH2SS (CH2 ) 3Na
~d) CLCH2CH2Cl ~ lYaSS(CH2)3SO3Na ~ NaS(CH2)3SO3Na ~
NaO3S(CH2)3SSCH2CH2S (CH2 )3SO3Na
Typical polysulfide compounds which may be
employed according to the invention include the following
compounds which are summarized in Table II. In the formula
: 15 R' (S 3nR-So3M (1)
M represents a sodium cation and R, R', and N are a~
lndicated in Table II.
TABLE II
Sulfonated Polysulfide Cooperating Brighteners of the
Formula R' (S ~ RSO3Na
Additive R' n R
A-l ~ 2 (CH2)3
CH3
A-2 ~ 2 (CH2)3
A-3 H3C ~ 2 (CH2)3
A-4 2 (cH2)3
1~
H3C~ J
-- 10

~ 038326
TABLE II cont.
Additive O n R
A-5 C~ 2 ~C~2 )3
~CHa )aSO3Na
A-6 NH~CH2 )3SO3H 2 ~CH2 )3
SO3Na
H,~,~ ~C~13
A-8 NaO3 S ~CH2 ) 2 2 ~CH2 ) 2
A-9 NaO3S~CH2)3 2 ~CH2)3
A-10 NaO3S~CH2)4 2 ~CH2)4
A-ll NAO3S (CH2 )3 ~CH2 )3
A-12 ~a ~or H) 2 ~CH2 )3
A-13 NaO3S(CH2)3S2~CH2)2 2 ~CH2)3
A-14 NaO3S~CH2)3S2CH2CH = CHCH2 2 ~CH2)3
A-15 NaO3S(CH2)3S2CH2c-ccH2 - 2 ~CH2)3
A-16 NaO3S(CH2)3S2(CH2)3 2 ~CHz)3
-- 11 --

10383Z6
TW IE II cont.
Additive R' n R
A-17 CH3CH2CH2CH2 2 (CH2)3
A-18 H2C=CHCH2 2 ~CH2)3
A-l9 HC_C~2 2 (CH2)3
A-20 ~ 2 (CH,~,
A-21 H03 ~ 2 (CH2)3
A-22 Na03SCH2CH(OH)cH2 2 CH2CH(OH)CH2
The R'(S?nNa compound may be prepared by the
reaction of R'SNa with sulfur if R' is an aromatic group
, .
~compounds A-l, A-2, A-3, A-4, A-5, A-20). A typical
procedure is: To a methanol solution (150 ml) containing
sodium methoxide (0.1 m) is added the R'SH (0.1 m) compound.
The mixture is stirred at room temperature until the compound
has dissolved. Sulfur powder (0.1 gram-equivalent) is added
and the mixture stirred until all the sulfur is dissolved.
Propanesultone ~0.12 mole) is added to the stirred solution.
Stirring is continued for 30 minutes, during which time a
solid precipitates from the solution. Acetone (250 ml) is
then added to give additional solid, which is then ~iltered,
washed with acetone, and dried.

1038326
Aliphatic R'(S)nNa compounds are prepared by
reaction of R'Q ~ith Na2Sn, where Q is Cl, ~r, I,
-OS02C6H~, -OS02C6H4 CH3, -OS02CH3 (e.g. compounds A-17,
A-18, A-l9). A typical procedure is: To a stirred
methanol solution (150 ml) containing sodium disulfide
(0.1 m) is added dropwise a solution of R'Q ~0.1 m) in
methanol (50 ml) at room temperature. The reaction i8
8 lightly exothermic. After the addition is completed the
mixture is stirred for 30 minutes. Propane sultone
(0.12 m), which may be dissolved in methanol (50 ml), is
added to the stirred mixture. During the addition of
propane sultone a w~ite solid usually precipitates from
the solution. The mixture may be heated and stirred at
65 C. for 30 minutes and then cooled. Acetone i8 added
and the solid is filtered and dried.
aompounds of the type of A-9, A-10, A-ll, A-12
are prepared by the reaction of an alkali metal polysulfide
(Na2S2, Na2S4, etc.) with a sultone.
Compounds of the type of A-L3, A-14, A-15, A-16
are prepared according to the reaction sequence:
(1) QRQ ~ Na2Sz ~ NaS2RS2Na ~ 2NaQ
(2) NaS2RS2Na ~ 2fHaCH2lCH2 ~ NaO3S(CH2)3S2RS2(CH2)3S03Na.
SO2
Instead of sultones, haloalkane sulfonates,
including e.g. ClCH2CIIOHCI12S03Na ~prepared by reaction of
2S epichlorohydrin with sodium bisulfite), and in general
compounds of the type QRS03M, may be used.
- 13

10383Z6
Some poLysulEide compounds may also be prepared
by the direct sulfonation of an organic polysulfide
(e.g. A-7; or A-21 by sulfonation of A-20).
Symmetrical disulfides may be prepared by careful
oxidation of compounds o the type HSRS03Na.
It is sometimes advantageous to prepare aqueous
stock solutions o the sulfonated polysulfides containing
small amounts o copper sulfate and/or sulfuric acid. Some
precipitation may occur which is eliminated by filtration.
The suLfide compounds of the invention may be
present in the coppeI bath in effective amounts of about
0.001 g/l - 1.0 g/l, preferably 0.005 g/l - 0.2 g/l.
The heterocyclic sulfur-containing cooperating
additives o this invention contain the grouping:
a heterocyclic sulfur compound containing
the grouping
- N = C - C -
(~ I , ' .
~ OJz R"
and/or tautomers thereof,
where the nitrogen atom and the two
carbon atoms are part of a heterocyclic
ring wherein Z is 0 or 1; and
R" is hydrogen, a metal ion or one of the ~roups
~ NR"' ~ NR"'
c c\ - 8 - N(R"')2
N(R"' )2 ~ R"' , S
- 14 -

1038326
where R"' is hydrogen, an alkyl group of 1 - 6
carbon atoms, aryl, alkaryl or aralkyl group.
Alternatively, the heterocyclic sulfur compound
is of the formula
(Y) - N
(X) - C SRl,
and/or tautomers thereof, N-oxides of said compound, isothiourea
derivatives, isothioamide derivatives and dithiocarbamate deriv-
atives thereof where Rl is hydrogen, a metal cation, or the groups
~NR" ~NR"i
- C ~ - C~ - C NR'2
NR"'2, R" , S
wherein R" is hydrogen, an alkyl group of 1 - 6 carbon atoms,
aryl, alkaryl, or aralkyl; X is - CR" = or - CR'2 - and Y is
a divalent organogroup of 2 to 16 carbon atoms which forms 1 or
more 5 through 7 membered cyclic ring structure or structures
with the group
~X) - C = N -
S
: Rl
; wherein X and Rl are as hereinbefore defined.
Certain of the above subject matter is described in
our Canadian Patent No. 924,259 of April 10, 1973.
- 15 -

10383Z6
Typicnl parent substances are:
2-mercapto pyridine, 2-mercapto quinoline, 1- or 4- mercapto
isoquinoline; their N-oxides; allcyl, hydroxy, alkoxy,
mercapto dexivatives of these compounds derived by substitution
on the ring carbon atoms; isothioureas, isothioamides and
their salts with acids, dithiocarbomates derived by substitution
on the bivalent sulfur atom. Among the heteroaliphatic ring
compounds thiocaproLactam gives especially good results.
The mercapto compounds may be dissolved before
addition to the copper bath in water containing equivaLent
amounts of alkali hydroxides, in dilute acids or in suitably
organic solvents, e.g. alcohols. The isothiourea, isothioamide,
dithiocarbamate derivates are dissolved in water, dilute acids
or in suitable solvents such as alcohols, but not in alkali
hydroxides as they may decompose therein.
The function of the heterocyclic compounds of
group (B) is to produce, in conjunction with the sulfonated
poly~ulfides' of group (A) and the polyethers of group (C),
leveling and to increase the brightness of the deposits
obtained, especially in the low and medium current density
range.
The heterocyclic compounds of formula group tB)
may be employed in effective amounts, typically 0.1 - S0 mg/l
and preferably 0.5 - 20 mg/l of total aqueous 'bath composition.
Typical heterocyclic group (B) compounds which may 'be employed
accordin~ to the invention are given in Table III.
- 16

10383Z6
TI~BLE III
HETEROCYCI.IC COMPOUNDS (13)
B FORMUIA NAr~SE
1 ~ 2-Mescaptopyridine
N - SH (2-Pyridinethiol)
~ NH. HCl
2 ~ ~ ~ 2-S-Pyridyl
isothiouronium
-S C\ chloride
NH2
3 . ~ 2-Mercaptopyridine-
SH ~l-Hydroxy-2-
pyridinethione)
.. O
4 ~ / NH. HCl 2-S-Pyridyl isothiouro-
S-C nium chloride N-oxide
. N NH2
O
CH3
~ 2-Mercapto-
SH 4-methylpysidine
N
CH3
6 ~ ~ . HCl 4-~Sethyl-2-S-pyridyl
S-C i~othiouronium chloride
N NH2
- 17

,! ~ 038326
~ LE III ~Continued)
B FOnMUL~ N~ME
__ _
Cl~3.
7 ~ 2-Mercap~o-4-
~ SH metihylpyridine-N-
o
C~3
8 ~ NH. HCl 4-Methyl-2-S-pyridyl
isothiouronium chloride
~ SC N-oxide
~,1 NH2
9 ~ 2-Mercapto-6-
H3C ~ SH methylpyridine
10~ / NH. HCl 6-Methyl-2-S-pyridyl
H3 ~ SC isothiouronium chloride
N \ NH2
11 ~ 2-Mercapto-6-methyl
N H pyridine-N-oxide
o
12 ~ /~ . HCl 6-Methyl-2-S_pyrid
l ~ isothiouronium
H3C- ~ - S~ chloride N-oxide
~1, M~2
-- 1~ --

" ~038326
T~ III (Continued)
B FORMUL~ N~ME
13 ~ SH 2-Merc~ptoquinoline
N
14 ~ NH. HCl 2-S-Quinolyl
~ S ~ isothiouronium chloride
~ 2-Mercaptoquinoline
~ SH N-oxide
." ~ .
16 ~ ~ NH. HCl 2-S-Quinolyl
~ SC\ N-oxide
~ NH2
17 ~ 2-Mercapto-6-hydroxy
HO ~ SH pyridine
N
-- 19 _ ,,

1038326
TAIlLE IIT. ~Continucd)
B FORMNLA N~ME
.
18~ ~ NH. HCl 6-Hydroxy-2-S-
: HO~ ~,L-S pyridyl isothiouronium
chloride
NHz
19 ~ 2,6-Dimercapto
HS ~ SH pyridine
HCl.HN ~ / NH.HCl 2 ~-SS-Pyridyl
C-S ~ ~ S- bis-isothiouronium
/ ~ \ chloride
H2N NH2
21 ~ Thiocaprolactam
__ (2-Thioxohexamethylene
S imine)
.
22 ~ 2-S-Pyridyl-N-
S-C N(C2H5)2 diethyL dithiocarbamate
S
- 20

l03s3a6
The heterocyclic cooperating additives of Table III
nre available commercially. The he~erocyclic compounds of
Table III (with the exception of B-21) are generally prepared
from the corresponding halogen compounds e.g. 2-chloropyridine
S either by direct reaction with alkaLi metal hydrosulfide or
more frequently just with thiourea joining the respective
isothiouronium compounds, which may be conver~ed by alkaline
hydrolysis into the corresponding mercapto compounds. B-22 was
synthesized by reaction of 2- chloropyridine with sodium
diethyldithiocarbamate.
Polyethers which may be used according to the process
of the invention mQy-have at least S ether oxygen atoms and
include polyethers of the formulae-
R"'-0-Z
R"'-S-Z
R"\
N-Z
R "'
R"'-N~
R""(Z)m
R""(SZ)m
R""(NZ)m
R''''(~z )m
where R"' is a monovalent radical such as H, allcyl, alkenyl,
allcynyl, alkylaryl, arylallcyl or a heterocyclic radical; and
- 2]

1 0 ~3~
n~ is a m- valent aliphatic, aromatic or heterocyclic
radical; m=2 to 100; and %=(cuH2uo)r(cvH2vo)sT~ where
u and v=0 to 4, but at least one o u or v must be greater
than zero; r + s = 6 to 200,000; r=0 when u=0; s=0 when v=0;
and T = H, alkyl, benzyl, -S03M, -CuH2uSO3M, -P03H2, or
CUH2UNHR ~
Suitable polyethers which may be used according
to the invention include polyethers set forth in Table IV.
The polyether additives may be employed in effective
amounts, typically 0.005 - 10.0 g/l and preferably 0.1 -
1.0 ~/1 of total aqueous bath compositions.
- 22

10383Z6
TA~LE IV
Cooperatin~ Polyethers
Additive 7H3 ,CH3 ~CH3 CH3
C-l CH3 - CH - CH2 - C - C _ C - C - CH2 - CH - ~l3
O O
H2 1 ~ ~H2 ¦
L o Jm l O ~n
H H
m + n = 30
C-2 Formula C-l wherein m + n = 15.
C-3 Formula C-l wherein m + n = 10.
C-4 CH3 - C - CH2 - ~ - ~ - O - (CH2CH20)XH
CH3 CH3
x = 9 - 10
C-5 Formula C-4 wherein x = 30.
C-6 Formula C-4 wherein x = 40.
C-7 CgUlg- ~ _o~cHzcHso)
C-8 n-Cl2H2~0(CH2CH20)2~H
~H
C-9 n-CxH2~ C - CH3
~ N - (CH2C1l20)~
I (cH2cH2o)zH
x - 9 - 12
y ~ z = 15
_ 23

. ~0383Z6
T~nLE IV (Cont ;nucd )
Additive
H(C2H40)y(c3H60)x\ ~(C3H60)X(C2H40)yH
C-10 CH2CH2N
H(CzH40~y~c3H6o)x (C3H60)X~C2H40)yH
wherein x i8 about 3
and y i9 about 3-4
C-ll HO(C2H40)XH
wherein x is about 13
C-12 HO(C2H40)xH
wherein x is about 33
C-13 HO(C3H60)xH
wherein x i9 about 6-7
C-14 HO(c3H60)x H
wherein x is about 12
CH3 ICH3
C-15 CH3CH21 - CHz - CH2 - ~ - CH2CH3
O
CH2~ H
L ~H2~ L ~H2
CHCH3 CHCH3
CH2 nL ~oH2 _ n
H H
wherein m = about 12 - 15
n = about 1 - 2
_ 24

103B3~6
l~LE IV (Con~inlled )
AdditiveICH3 CH3
C-16CM3CH2C - CM2CH2 - C - CH2CH3
O O
r f ~ 1
L C,U2~l 1 ,CH2 b
CH2 CH2 1
CN2 m _ ~CIN~
H H
m = about }2 - 15
n = 1 - 2
C-17 Cl2H2ss(cH2cH20)2oH
H H
.. l, , ~
C-18 H2N - IC - CH2 ~OCH2C~p NH2
H3 CH3
wherein p is about S - 6.
H H
C-l9 H2N - C - CH2 ~OCH2C~p NH2
CH3 CH3
wherein p i9 about 16

1038326
TABI~ IV ~Continued)
Additive
C-20 CH3(CH3)5CHCH3
ltc3ll6o)2 (C2H40)20H
C-2} CH3(CH2)70(c2H40)2o(c3H6o)3H
C-22 CH3(CH2)ll O(C3H60)3~C2H40)l.~H
C-23 H(OH4C2)lSO(CH2)l0 O(C2H4o)lsH
C-24 H(OC2H4)8 CH3 CH3 - (C2H40)8H
NCH2C - CH2 - CH - CH2 - CH2N
H(OH4C2 )8 CH3 ~C2H40)8H
C-25 HO(C2H40)x H
. wherein x i8 about 136 (MW i9 about 6,000)
C-26 HO(C2H40)x H
wherein x is about 454 (MW is about 20,000)
C-27 HO(C2H40)x H
wherein x i9 about 4540 (MW is about 200,000)
- 26 -

; ~038326
The chloride ion content of the aqueous copper
sh~, /J
plating bath compositions of the invention ~ be at lea~t
about 0.5 mg/l and~typically from 1.0 mg/l to 500 mg/l of
aqueous copper plating bath. Good results may ~e obtained
S using a chloride ion concentration of from about 3 mg/l to
100 mg/l of aqueous copper plating ~ath composition, and
preferably a chloride ion concentration of from 20 mg/l to
80 mg/l of aqueous copper plating solution/is useJ
B Other optional additives used were the following
dispersing agents:
TABLE V
Additives
D-l C~z ~ SOaNa )
H H
D-2 NaO3S ~ ~ SO3Na I ~ SO3Na
C--~ C--
H H
SO3Na
D-3 ~ SOaNa
where n = 3 to 6
_ ~7

1038326
TABLE V ~Continued
Additives
(S03Na)n C4Hg
D-4 ~ SOJNa)m
n ~ m = 1 - 2 and preferably n = 0 when m = 1
CnH2n+l /CnH2n+.l
D-S ~ ~ SO~M,
SO3Ml
wherein each n i8 an integer 4-12 (preferably 4-8)
and each ~1 and M2 is an alkali metal
(preferably Na or K) or a hydrogen atom.
The following examples are set forth for the
,purpose of providing those skilled-in-the-art with a better
understanding of this invention, and the invention is not
to be construed as limited to such examples.
In these examples the aqueous copper plating bath
contains unless noted otherwise:
0 CuS04 ' SHzO 220 g/l
H2S04 60 g/l
chloride ion 0.06 g/l
- 2~ _

10~
The plating experiments were performed in a Hull
Cell containing 250 ml. of this acid copper sulfate bath.
The Hull Cell allows one to observe the appearance of the
deposit over a wide current density range. In order to judge
the degree of leveLing the polished ~rass panels used for
these plating tests were scratched with 4/0 emery polishing
paper over a horizontal ~and of about 10 mm. width. The
plating temperature used in these experiments was the ambient
room temperature (24 - 30C.), unless otherwise stated. The
total current was 2 amperes and the plating time 10 minutes.
Air agitation or mechanical agitation with an oscillating
paddle was used as specified in Table VI. The sulfonated
polysulfide compounds used are described in Table II, the
heterocyclic sulfur compounds in Table III, and the polyethers
15 in Ta~le IV.
For convenience, the results shown in Table VI
are classified according to (1) the width of the lustrous
current density range (semi-bright to bright) and according to
~2) the degree of leveling under the indicated experimental
conditions (i.e. a 250 ml. Hull Cell, 2 amperes current, and
a ten minute plating time on a metal strip having a band
uniformly scratched with 4/0 grit emery paper).
Each property in groups (1) and (2) is independently
measured as "poor", "fair", "good", and "very good" as follows:
- 29

r
10383a6
Property (1) Property (2)
Rating Width of lustrous current Rating Degree of leveling
. density ran~e
~__ ~ . _ _
Poor Less than one halP of Poor No visual change in
_ length of test panel _ original roughness
_ of scratched band _
Fair More than one half and Fair Noticeable decrease
less than two thirds of _ in roughness, but
length of test panel scratches still
_ _ . _ visible
Good More than two thirds but Good Roughness decreased
_ less than entire length . and portions of
. 10 of test panel scratches completely
Entire length of test Very Scratches on the
panel i8 lustrous G _ portion of the panel
. having a current
density greater
than 2.5 asd. are
. practically
. invisible
.
The combination of the panel satings given with
respect to width of lustrous current density range and degree
of leveling determine the final clasQification set forth in
the "Results" column of Table VI according to the following:
Results Definition
_ _ _ _
Excellent Very good leveling and very
good bright current density
.20 range
Very good Very good leveling and good
.bright current density range
-- Good Good to very good leveling and
good to very good semi-bright
current density range or:
good leveling and good to very
good ~right current density
range
Poor Poor leveling and/or poor
lustrous current density range
Fair All intermediate panels not
otherwise cl~ssified
- 30

~;
TABLE VI
EXAMPIE AMOUNTS TYPE OF
NO. ADDITIVE g/l AGITATION RESULTS
A-l 0.02 Air Poor
C-l 1.0
2 ~-1 0.02 Air Very Good
C-l 1.0
B-3 0 . 006
3 A-l 0.02 Air Excellent
C-l . 1.0
B-ll O. 004
4 A-l 0. 02 . Air Excellent
C-l 1.0
B-12 O. 003
A-l 0.02 Mechanical Poor
C-7 1.0
6 A-l 0.02 Mechanical Excellent
C-7 1.0
B-5 O. 002
7 A-l 0.02 Mechanical Poor
C-8 1.0
8 A-l 0.02 Mechanical Excellent
C-8 1.0
B-16 O. 002
9 A-2 O. 02 Ai~ Poor
C-13 1.0
A-2 0 . 02 Air Very Good
C-13 1JO
B-21 O. 003
11 A-6 O. 02 Air Poor
C-l 1.0
12 A-6 O. 002 Air Good
C-l 1.0
B-l 0.003
13 A-6 O. 02 Air Good
C-l 1.0
B-3 O. 004 ~ _
14 A-6 O. 02 Air Very Good
C-l 1.0
B-13 O. 002
A-9 O. 015 Air Poor
C-13 O. 25
- 31 -

- ,
1038326
TABLE VI (Continued)
EXAMPLE AMOUNTS TYPE OF
NO. ADDITIVE g/l AGITATION RESULTS
16 A-9 0.015 Air Very Good
C-13 0.25
B-l 0.002
17 A-9 0.015 Air Very Good
C-13 0.25
B-2 0.003
18 A-9 0.015 Air Very Good
C-13 0.25
B-5 0.003
19 A-9 0.015 Air Poor
C-22 1.0
A-9 0.015 Air Excellent
C-~2 1.0
B-l 0.003
21 A-9 0.015 Air Very Good
C-22 1.0
B-3 0.004
22 A-9 0.015 Air Excellent
C-22 1.0
B-12 0.003
23 A-9 0.015 Air Good
C-22 1.0
B-13 0.002
24 A-9 0.015 Air Good (less
C-22 1.0 micro-roughness)
B-13 0.002
D-l 0.4
A-9 o.oi5 Air Good
C-22 1.0
B-14 0.020
26 A-9 0.015 Air Excellent
C-22 1.0
B-16 0.002
27 A-9 0.015 Air . Excellent
C-22 1.0
B-18 0.004
28 A-9 0.015 Air Good
C-22 1.0
-B-19 0.002
29 A-9 0.015 Air Good
C-22 1.0
B-20 0.010
- 3~ _

10~B326
T~nlE VI (Con~inued)
EXAMPLE AMOUNTS TYPE OF
NO. ADDITIVE g/l AGITATION _ESULTS
A-9 0.015 Air Excellent
C-22 1.0
B-21 0.003
31 A-9 0.015 Air Excellent
C-22 1.0
B-22 0.02
32 A-9 0 . 015 Air Poor
C-25 0.25
33 A-9 O. 015 Air Excellent
C-25 0.25
B-S 0.002
34 A-9 O. ois Air Poor
C-25 1.0
A-9 0.015 Air Excellent
- . C-25 1.0
B-ll 0. 004
36 A-9 O. 015 Air Good
C-25 1.0
B-13 0.002
37 A-9 O. 015 Ais Poor
C-27 0, 4
38 A-9 0 . 015 Air Very Good
C-27 0,4
B-S 0.002
39 A-ll 0. 02 Air Poor
C-10 1.0
A-ll O . 02 Air Good
C-10 1.0
B-ll 0.004
41 A-ll 0. 0~ Air Good
C-10 1.0
B-12 0,003
42 A-12 0.02 Air Poor
C-18 1.0
43 A-12 0. 02 Air Good
C-18 1 . O
B-2 0.004
- 33

- ^ ~0383Z6
T~LE VI (Contlnued)
E,Y~MPLE AMOUNl'S TYPE Ol~
NO. ADDITIVE: ~/1 AGITATION RESULTS
44 A-12 O. 02 Air Cood
C-18 1.0
B-18 0.008
A-15 O. 02 and 0.04 Air Poor
C-15 1.0
46 A~-15 0.04 Air Very Good
C-15 1.0
B-l 0.002
47 A-15 O. 02 Air Very Good
C-15 1.0
B-3 0 . 004
48 A-15 0.02 Air Good
C-15 1 . O
B-13 0.002
49 A-17 0.02 Air Poor
C-21 1.0
: 50 A-17 0.02 Air Poor
C-21 1.0
D-l 0.4
51 A-17 0.02 Air Good but
C-21 1.0 . pitted
B- 18 0 . 006
52 A-17 0.02 Air Very Good
C-21 1.0
B-18 O. 006
D-l 0.4
53 A-18 0.02 Mechanical Poor
C-6 1.0
54 A-18 0.02 Mechanical Good
C-6 1.0
B-l9 O. 005 and 0.010
A-18 0. 02 Air Poor
C-26 ~.0
56 A-18 0. 02 Air Good
C-26 1 . O
B-l9 0.003
- 34

10383a6
Dispersin~ Agent~:
- Addition of a dispersing agent such as D-l to the
A + B + C combination sometimes improves the rating by
increasing the rate of leveling and/or the lustrous current
density range. ~Examples 51 and 52.)
S In other cases, addition of D-l does not appreciably
change the rating but increases the degree of brightness or
eliminates microroughness. (Examples 23 and 24.)
Fluoborate Bath:
For a fluoborate bath of the preferred composition
indicated in Table I, the additives of Example 35 gave equally
excellent results. Use of the fluoborate bath allows to
increase plating speeds by 50 to 100%.
Although this invention has been illustrated by
reference to specific embodiments, modifications thereof
which are clearly within the scope of the invention will be
apparent to those skilled-in-the-art.
- 35
.