Electrodeposition of copper

This invention relates to novel compositions and to a process for electrodepositing copper from an aqueous acidic copper plating bath containing at least one member independently selected from each of the following two groups: PA1 A. 0.005 gram per liter to 10.0 grams per liter of quaternized aryl and aralkyl amines selected from those exhibiting the formulae: ##STR1## wherein R', R", R'" and R"" are each independently selected from the group consisting of substituted and unsubstituted monovalent alkyl, aryl, aralkyl and cycloalkyl radicals provided that at least one aryl or aralkyl radical is present on each quaternary nitrogen atom; wherein Z is a bivalent hydrocarbon radical which may be substituted and/or interrupted by heteroatoms; wherein n=3 or 4; and wherein the Anion may be absent if one of the radicals R' to R"" carries an anionic substituent. PA1 B. sulfoalkyl sulfide compounds containing the grouping --S--Alk--SO.sub.3 M where M is one gram-equivalent of a cation and -- Alk -- is a divalent radical selected from a group consisting of unsubstituted and substituted aliphatic hydrocabon radicals containing 2 to 8 carbon atoms which may be interrupted by heteroatoms in an amount of 0.01 milligrams per liter to 1000 milligrams per liter.

This invention relates to novel compositions and to a process for 
electrodepositing copper from an aqueous acidic copper plating bath 
containing at least one member from each of the following two groups: 
A. 0.005 gram per liter to 10.0 grams per liter of quaternized aryl and 
aralkyl amines selected from those exhibiting the formulae: 
##STR2## 
wherein R', R", R'", and R"" are each independently selected from the 
group consisting of alkyl, aryl, aralkyl, alkaryl and cycloalkyl provided 
that at least one aryl group is present; 
B. sulfoalkyl sulfide compounds containing the grouping --S--Alk--SO.sub.3 
M where M is one gram-equivalent of a cation and -- Alk-- is a divalent 
radical selected from a group consisting of unsubstituted and substituted 
aliphatic hydrocarbon radicals containing 2 to 8 carbon atoms which may be 
interrupted by heteroatoms in an amount of 0.01 milligrams per liter to 
1000 milligrams per liter. 
DETAILED DESCRIPTION 
Practice of this invention results in copper deposits which, depending on 
bath composition and operating conditions, are very suitable for 
rotogravure applications, or for the plating of printed circuit boards, or 
for electroforming, or are fully bright and strongly leveling for 
decorative purposes. These advantages are realized by addition of at least 
one member of each of the following two groups: 
A. 0.005 gram per liter to 10.0 grams per liter of quaternized aryl and 
aralkyl amines selected from those exhibiting the formulae: 
##STR3## 
wherein R', R", R'", and R"" are each independently selected from the 
group consisting of substituted and unsubstituted monovalent alkyl, aryl, 
aralkyl and cycloalkyl radicals provided that at least one aryl or aralkyl 
radical is present on each quaternary nitrogen atom; wherein Z is a 
bivalent hydrocarbon radical which may be substituted and/or interrupted 
by heteroatoms; wherein n=3 or 4; and wherein the anion may be absent if 
one of the radicals R' to R"" carries an anionic substituent. 
B. sulfoalkyl sulfide compounds containing the grouping --S--Alk--SO.sub.3 
M where M is one gram-equivalent of a cation and -- Alk-- is a divalent 
radical selected from a group consisting of unsubstituted and substituted 
aliphatic hydrocarbon radicals containing 2 to 8 carbon atoms which may be 
interrupted by heteroatoms in an amount of 0.01 milligrams per liter to 
1000 milligrams per liter. 
To obtain strongly leveling copper deposits, and often also to obtain fully 
bright copper deposits over a wide current density range, further addition 
of at least one member of the group of leveling agents that is diffusion 
controlled inhibitors, (Group (C) is required. 
Simultaneous presence of at least one member of each group (A) and (B) in 
the acid copper bath produces superior copper electrodeposits to those 
obtained when only members of one group are present in respect to one or 
more of the following properties: greater smoothness, greater brightness, 
greater hardness, or greater softness and ductility, and/or better 
response to the addition of a leveling agent. 
Structure II (N-oxide) may be derived from I by replacement of one radical 
and of the anion by an oxygen atom, bound to the nitrogen by a polar 
coordinate linkage. 
Structure III (reaction product of an N-oxide with propane or butane 
sultone) may be derived from I by replacement of one radical by the 
--O(CH.sub.2).sub.n SO.sub.3 .sup.- or --O(C.sub.n H.sub.2n )SO.sub.3 
.sup.- group. 
The amines of this invention may be present in the copper bath of this 
invention is effective amounts of 0.01 grams per liter to 10 grams per 
liter of total aqueous bath composition. 
Typical amines which may be employed according to this invention include 
the following compounds which are summarized in Table I. 
Anion.sup.- may be OH.sup.-, SO.sub.4 .sup.=/2, HSO.sub.4 .sup.-, BF.sub.4 
.sup.-, CH.sub.3 SO.sub.3 .sup.-, C.sub.6 H.sub.5 SO.sub.3 .sup.-, 
CH.sub.3 C.sub.6 H.sub.4 SO.sub.3 .sup.-, H.sub.2 PO.sub.4 .sup.-, 
HPO.sub.4.sup.= /2, PO.sub.4 .tbd./3, etc. It may also be Cl.sup.-, but an 
acid copper bath tolerates Cl.sup.- only up to about 150 mg/l and 
preferably 60 or 80 mg/l. Thus the Anion.sup.- of Formulae I and II may be 
Cl.sup.- if these Amines are rather effective and consequently used only 
in relatively small concentrations. The concentrations of Br.sup.- and 
especially I.sup.- tolerated without harm to the quality of the copper 
deposit are considerably smaller. 
TABLE I 
______________________________________ 
COOPERATING AMINES 
##STR4## 
2. [C.sub.6 H.sub.5 CH.sub.2 N.sup.+ (CH.sub.2 CHOHCH.sub.3).sub.3 ] 
Cl.sup.- 
3. [C.sub.6 H.sub.5 CH.sub.2 N.sup.+ (CH.sub.3).sub.3 ] OH.sup.- 
##STR5## 
5. [(C.sub.6 H.sub.5 CH.sub.2).sub.2 N.sup.+ (CH.sub.3).sub.2 ] 
Cl.sup.- 
##STR6## 
##STR7## 
##STR8## 
##STR9## 
10. 
##STR10## 
##STR11## 
##STR12## 
______________________________________ 
The cooperating sulfoalkylsulfides exhibit the formula: 
EQU RS -- Alk -- SO.sub.3 M 
where M denotes one gram-equivalent of a cation and -- Alk-- is a divalent 
aliphatic group of 1-8 carbon atoms; -- Alk-- may be a saturated or 
unsaturated divalent aliphatic hydrocarbon group, which may or may not 
carry inert substituents such as hydroxyl, alkyl, hydroxyalkyl, and alkoxy 
in which the carbon chain may be interrupted by heteroatoms. Typical 
examples of -- Alk -- are: 
##STR13## 
In the compound R--S--Alk--SO.sub.3 M R may be a hydrocarbon radical 
preferably selected from the group consisting of alkyl, alkenyl, alkynyl, 
cycloalkyl, aryl, aralkyl, alkaryl, including such radicals when inertly 
substituted such as preferably sulfoalkyl. R may be a sulfide or 
polysulfide containing up to four bivalent sulfur atoms of these 
hydrocarbon radicals, such as Alk S.sub.n .sup.- and MO.sub.3 
S--Alk--S.sub.n .sup.-, where n = 1 to 4; or it may be a 
sulfoalkylthioalkyl group such as MO.sub.3 S--Alk--S--Alk--. 
R may be hydrogen or a metal cation or their sulfides and polysulfides 
MS.sub.n .sup.-. It may be a sulfonic group MO.sub.3 S-- (e.g. in the 
reaction product of sodium thiosulfate and 1,3-propanesultone, 
##STR14## 
or a heterocyclic ring which may be substituted by other sulfoalkylsulfide 
groups, etc. 
The sulfoalkylsulfides may be employed in effective amounts of 0.01 mg/l to 
1000 mg/l of total aqueous bath composition. Typical sulfoalkylsulfides 
which may be employed according to this invention include the following 
compounds which are summarized in Table II. 
TABLE II 
______________________________________ 
COOPERATING SULFOALKYL SULFIDES (SAS) 
OF THE FORMULA RS ALK SO.sub.3 M 
SAS NO. 
R Alk M 
______________________________________ 
1 NaO.sub.3 S(CH.sub.2).sub.3 S 
(CH.sub.2).sub.3 
Na 
2 NAO.sub.3 S(CH.sub.2).sub.3 SS 
(CH.sub.2).sub.3 
Na 
3 NaO.sub.3 S(CH.sub.2).sub.4 S 
(CH.sub.2).sub.4 
Na 
4 C.sub.6 H.sub.5 S 
(CH.sub.2).sub.3 
Na 
##STR15## (CH.sub.2).sub.3 
Na 
6 H (CH.sub.2).sub.2 
Na 
7 H (CH.sub.2).sub.3 
Na 
8 NaO.sub.3 S (CH.sub.2).sub.3 
Na 
9 
##STR16## (CH.sub.2).sub.3 
Na 
10 
##STR17## (CH.sub.2).sub.3 
Na 
11 
##STR18## (CH.sub.2).sub.3 
K 
12 NaO.sub.3 S(CH.sub.2).sub.3 
(CH.sub.2).sub.3 
Na 
13 NaO.sub.3 S(CH.sub.2).sub.3 S(CH.sub.2).sub.3 
(CH.sub.2).sub.3 
Na 
14 NaO.sub.3 S(CH.sub.2).sub.3 S(CH.sub.2).sub.6 
(CH.sub.2).sub.3 
Na 
15 C.sub.6 H.sub.5 (CH.sub.2).sub.3 
Na 
16 C.sub.6 H.sub.5 CH.sub.2 
(CH.sub.2).sub.3 
Na 
17 
##STR19## (CH.sub.2).sub.3 
Na 
18 NaO.sub.3 SCH.sub.2 CHOHCH.sub.2 S 
CH.sub.2 CHOHCH.sub.2 
Na 
19 
##STR20## (CH.sub.2).sub.3 
Na 
20 
##STR21## (CH.sub.2).sub.3 
K 
21 
##STR22## (CH.sub.2).sub.3 
K 
______________________________________ 
Another aspect of this invention is the one of obtaining strongly leveled 
copper deposits, that is copper deposits which are substantially smoother 
than the substrate on which they are deposited. In order to possess 
leveling properties the acid copper plating bath must contain besides at 
least one member of each of the groups (A) and (B) also at least one 
member of group (C) comprising the leveling agents, i.e. diffusion 
controlled inhibitors. 
Besides producing leveling the leveling agent frequently also increases 
brightness, and widens the bright current density range. It may also 
prevent roughness formation at high current density and increase hardness. 
An acid copper bath containing at least one additive from each of the two 
groups (A) and (B) responds much better to the addition of a leveling 
agent than a copper bath containing only members of one of the two groups 
or no members of these two groups. 
Leveling agents which cooperate very well with addition agents of groups 
(A) and (B) are those containing 
##STR23## 
These tautomeric groups may be a part of a noncyclic molecule, such as an 
open thiourea in which they become a part of the wider groups 
##STR24## 
or they may be a part of heterocyclic rings where they may become a part 
of the wider groups 
##STR25## 
and/or their corresponding tautomeric forms. 
Typical leveling agents of the open thiourea type operable in the practice 
of this invention are set forth in Table III of U.S. Pat. No. 3,682,788 
which issued Aug. 8, 1972, upon the application of O. Kardos et al., e.g., 
thiourea, N-ethylthiourea(1-ethylthiourea), N,N'-diethylthiourea 
(1,3-diethylthiourea), N-phenylthiourea(1-phenylthiourea), etc. 
Typical leveling agents of the heterocyclic type are set forth in Table III 
of U.S. Pat. No. 3,542,655 which issued Nov. 24, 1970, upon the 
application of O. Kardos et al., e.g., 2-thiazolidinethone 
(2-mercaptothiazoline), 2-imidazolidinethione(ethylenethiourea) and its 
N-hydroxyethyl derivative, 2-pyrimidinethiol(2-mercaptopyrimidine) and in 
Table III of U.S. Pat. No. 3,804,729 which issued Apr. 16. 1974, e.g. 
2-mercaptopyridine, 2-mercaptoquinoline, their N-oxides, and other 
derivatives in which the --SH group is replaced by 
##STR26## 
and similar groups. Also levelers which instead of the group 
##STR27## 
contain the corresponding mercury compound 
##STR28## 
cooperate very well with the Amine plus Sulfoalkylsulfide combination. 
A different type of cooperating leveling and brightening agent comprises 
relatively high-molecular cations such as basic phenazine azo dyestuffs 
like Janus Green B (diethylphenosafranine azo dimethylaniline, color Index 
No. 11050) or Janus Black (diethylphenosafranine azo phenol, C. I. Basic 
Black 2, Color Index No. 11825), and certain cationic polymers such as the 
polyalkyleneimines and the polymers and copolymers of 2-vinylpyridine 
and/or 2-methyl-5-vinylpyridine and their quaternization products with 
alkyl halides, benzyl halides, or 1,3-propanesultone. Simultaneous use of 
at least one member of each of these two types of leveling agents, 
together with at least one member of each group (A) and (B), often results 
in beneficial effects as compared with those obtained with levelers of 
only one type, in respect to the degree and the current density range of 
brightness and leveling. 
Another type of compounds which often exerts beneficial effects on the 
copper electrodeposit when used in conjunction with at least one compound 
of each of the two groups (A) and (B), or of each of the three groups (A), 
(B) and (C) are the condensation products of an aldehyde, especially 
formaldehyde, with napththalene sulfonic acids, such as methylene 
bis-(2-naphthalene sulfonic acid) or higher molecular condensation 
products of this type in which, for instance, three, or, more generally, 
n, napthalene sulfonic acid groups are linked by two, or, more generally, 
n-1, methylene groups. Addition of such compounds, e.g. of 0.01 to 5 g/l 
of the sodium salt of methylene bis-(2-naphthalene sulfonic acid) often 
increases the brightness and high current density smoothness of copper 
deposits as compared with deposits obtained from copper baths containing 
only members of groups (A) and (B), or only members of groups (A), (B) and 
(C), as shown in Example 1. 
Still another type of compounds which often exerts beneficial effects when 
used in conjunction with compounds of the two groups (A) and (B), or with 
compounds of the three groups (A) (B) and (C) are the polyethers, 
especially those of rather high molecular weight. As dilute concentrations 
as 0.001 g/l to 0.005 g/l of a polyethyleneglycol of a molecular weight of 
1000 or 6000 or 20,000, or of a nonylphenol condensate with 100 moles 
ethylene oxide, or of a block polymer of 80% ethylene oxide and 20% 
propylene oxide and approximate molecular weight 5000, considerably 
increase leveling, especially in the low current density area, and often 
also increases brightness and bright current density range (See examples 
2, 3, 5 and 8). 
The polyether additives may be employed in amounts of 0.001 to 10 grams per 
liter. 
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 of this invention include the following: 
______________________________________ 
SULFATE BATH 
(1) CuSO.sub.4 . 5H.sub.2 O 
30-300 g/l 
H.sub.2 SO.sub.4 10-250 g/l 
Cl.sup.- 0-150 mg/l 
FLUOBORATE BATH 
(2) Cu(BF.sub.4).sub.2 50-600 g/l 
HBF.sub.4 1-300 g/l 
H.sub.3 BO.sub.3 0-30 g/l 
Cl.sup.- 0-150 mg/l 
______________________________________ 
For the deposition of bright, leveling copper about 220 g/l of CuSO.sub.4 
.5H.sub.2 O or CU(BF.sub.4).sub.2, about 60 g/l of H.sub.2 SO.sub.4 or 3.5 
g/l of HBF.sub.4, and about 20 to 80 mg/l of chloride ion are preferred. 
For high-speed plating, e.g., the plating of printing rolls, higher 
concentrations of the free acids and/or of the copper fluoborate are often 
preferred. For the plating of printed circuit boards, which requires high 
throwing power, low metal and high acid concentrations are most suitable. 
The plating conditions for electrodeposition from the aforementioned baths 
may, for example, include temperatures of 10.degree. C.-60.degree. C. 
(preferably 20.degree. C.-40.degree. C.); pH (electrometric) of less than 
about 2.5; and a cathode current density of 0.1-50.0 amperes per square 
decimeter (asd). 
The substrates which may be electroplated in accordance with the process of 
this invention may include ferrous metals, such as steel, iron, etc., 
bearing 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, nickel alloys with other metals 
such as cobalt or iron; aluminum, including its alloys, after suitable 
pretreatment; and non-conducting materials, e.g., plastics, after suitable 
pretreatment, etc.

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. 
The plating experiments reported in the following examples were performed 
-- unless otherwise stated -- in a Hull Cell containing 250 ml of 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 brass panels used for these plating tests 
were scratched with 4/0 emery polishing paper over a horizontal band of 
about 10 mm. width. The plating temperature used in these experiments was 
the ambient room temperature (24.degree.-30.degree. C.) unless otherwise 
stated. The total current was 2 amperes and the plating time 10 minutes. 
Air agitation was used in all cases. The amines used are listed in Table 
I, the sulfoalkylsulfides in Table II. 
Two types of acid sulfate copper baths were used in these experiments: 
______________________________________ 
Type 1.) Regular Sulfate Copper containing 
CuSO.sub.4 . 5H.sub.2 O 
220 g/l 
H.sub.2 SO.sub.4 
60 g/l 
Chloride ion 
0.06 g/l 
and Type 2.) High-Throw Sulfate Copper containing 
CuSO.sub.4 . 5H.sub.2 O 
100 g/l 
H.sub.2 SO.sub.4 
200 g/l 
Chloride ion 
0.06 g/l 
______________________________________ 
The chloride concentrations indicated above are those after addition of the 
various additives as some amines of Table I contain chloride. 
The hardness values given in Example 1 refer to microhardness obtained with 
a diamond pyramid indenter under a load of 50 grams (DPH.sub.50) on copper 
deposits about 0.025 mm. thick. 
EXAMPLE I 
In the regular copper bath (Type 1) 2 grams per liter of Amine No. 1 gave a 
dark matte Hull Cell deposit with high current density striations. Further 
addition of 0.015 grams per liter of Sulfoalkylsulfide No. 1 produced a 
smooth deposit which was bright from about 2.5 amp./sq.dm. upwards. Final 
addition of 0.0015 grams per liter of N,N'-diethylthiourea gave a bright 
leveling copper deposit. 
In the High-Throw copper bath (Type 2) 0.4 grams per liter of Amine No. 1 
gave a dark matte copper deposit in the Hull Cell. Further addition of 0.6 
grams per liter of the sodium salt of methylene bis-(2-naphthalene 
sulfonic acid) produced a uniform satin copper deposit, and final addition 
of 0.0015 grams per liter of Sulfoalkylsulfide No. 1 produced a uniform 
semi-bright copper deposit which was ductile and rather soft (DPH.sub.50 = 
104) with excellent coverage of the backside of the Hull Cell panel. This 
combination should be very suitable for the through-hole plating of 
printed circuit boards. 
EXAMPLE II 
0.5 g/l of Amine No. 2 gave in a copper bath of Type 1, a matte copper 
deposit above about 0.5 amp./sq.dm., a semibright deposit below this 
current density. Further addition of 0.015 g/l of Sulfoalkylsulfide No. 1 
produced a bright deposit above about 4 amp./sq.dm. Addition of 0.0015 g/l 
of 2-mercaptothiazoline as the third additive slightly improved brightness 
and bright current density range and produced some leveling. Final 
addition of 0.0025 g/l of Pluronic 10R8 (Wyandotte Chemicals Corporation), 
a block polymer having a polyoxyethylene group of approximate molecular 
weight 4000 in the center and two polyoxypropylene groups, each of 
approximate molecular weight 500, on either end, gives a very bright and 
strongly leveling copper deposit above about 0.5 amp./sq.dm. This 
quadruple combination of additives gives a copper deposit far superior to 
those attained with only three additives present e.g. in absence of Amine 
No. 2. 
Also the combined use of 0.5 g/l of Amine No. 2, 0.015 g/l 
Sulfoalkylsulfide No. 1, 0.005 g/l Janus Green and 0.0025 g/l Pluronic 
10R8 gives a bright and strongly leveling copper deposit above 0.5 
amp./sq.dm. 
EXAMPLE III 
In a copper bath of Type 1, addition of 0.1 g/l of Amine No. 5 gives a 
strongly striated copper deposit except below about 0.4 amp./sq.dm. where 
it is bright. Addition of 0.015 g/l of Sulfoalkylsulfide No. 1 produces a 
bright deposit from about 1.8 amp./sq.dm. to at least 12 amp./sq.dm. Final 
addition of either 0.0015 g/l of 2-mercaptothiazoline or 0.010 g/l of 
Janus Green strongly increases leveling and widens the bright current 
density range down to about 0.15 amp./sq.dm. Simultaneous addition of 
these two levelers further improves leveling and extends brightness over 
the whole Hull Cell panel. 
If, instead of one or both of these levelers, 0.005 g/l of a 
poly-2-vinylpyridine of approximate molecular weight 40 to 60,000 
quaternized with an alkylchloride or 0.005 g/l of a polyethoxylated 
polyethylene imine (approximate molecular weight 60,000) is added to an 
acid copper bath of Type 1 containing 0.1 g/l of Amine No. 5 and 0.015 g/l 
of Sulfoalkylsulfide No. 1 a strongly leveling bright copper deposit is 
obtained over a wide current density range. 
Also the combined addition of 0.05 g/l of Amine No. 5, 0.0025 g/l Pluronic 
10R8 and either 0.002 g/l of 2-mercaptothiazoline or 0.01 g/l Janus Green 
gives strongly leveling copper deposits which are bright over the whole 
current density range and superior to the deposits obtained in absence of 
one of these additives, e.g. of the polyether or of the Amine No. 5. 
EXAMPLE IV 
0.1 g/l of Amine No. 6 gives in an acid copper bath of Type 1 a copper 
deposit which is striated between about 0.8 and 6.0 amp./sq.dm., matte 
above this current density range and very thin below it. Addition of 0.015 
g/l Sulfoalkylsulfide No. 1 or of 0.02 g/l of Sulfoalkylsulfide No. 7 
produces a copper deposit which is bright and smooth above 0.6 amp./sq.dm. 
and semibright with good coverage below this current density. Final 
addition of 0.0015 g/l of 2-mercaptothiazoline produces strongly leveling 
copper deposits which are bright over the whole Hull Cell current density 
range (0 to more than 12 amp./sq.dm.) in either case. 
If, instead of sulfoalkylsulfides No. 1 or 7, 0.08 g/l of 
Sulfoalkylsulfides No. 12 or 16 are added to the copper bath containing 
0.1 g/l of Amine No. 6 smooth copper deposits with improved low current 
density coverage are obtained which are bright above about 1.5 amp./sq.dm. 
and show strong leveling above about 5 amp./sq.dm. on final addition of 
0.0015 g/l of 2-mercaptothiazoline. 
EXAMPLE V 
Addition of 0.15 g/l of Amine No. 7 gives strongly striated copper deposit 
with smooth brightness only below about 0.5 amp./sq.dm. Further addition 
of 0.015 g/l of Sulfoalkylsulfide No. 1 produces a smooth copper deposit 
which is bright above about 0.6 amp./sq.dm. Further addition of 0.0015 
2-mercaptothiazoline produces strong leveling above about 3 amp./sq.dm. 
and final addition of 0.0025 g/l of the polyether Pluronic F-68 (Wyandotte 
Chemicals Corporation), a block polymer having a polyoxypropylene group of 
approximate molecular weight 1750 in the center and two polyoxyethylene 
groups each of approximate molecular weight 3500 on either side) extends 
the bright current density range over the whole Hull Cell panel (0 to more 
than 12 amp./sq.dm.). 
EXAMPLE VI 
0.13 g/l of Amine No. 8, when added to an acid copper bath of Type 1, 
produces a uniform matte copper deposit over almost the whole Hull Cell 
panel. Further addition of 0.015 g/l Sulfoalkylsulfide No. 1 brightens the 
deposit below 4 amp./sq.dm. Final addition of 2-mercaptothiazoline 
produces a uniform hazy-bright copper deposit over the whole current 
density range except below 0.2 amp./sq.dm. where it is bright, which 
possesses strong leveling properties. 
EXAMPLE VII 
0.1 g/l of Amine No. 9, when added to an acid copper bath of Type 1, gives 
a copper deposit which is matter over almost the whole Hull Cell panel. 
Addition of 0.03 g/l of Sulfoalkylsulfide No. 1 gives a bright copper 
electrodeposit above 1 amp./sq.dm. and a semibright one below this current 
density. Final addition of 0.0015 g/l 2-mercaptothiazoline extends the 
bright current density range and produces moderate leveling. 
EXAMPLE VIII 
Amine No. 12 is so powerful that even 0.025 g/l produces a copper deposit 
which is bright and rough below about 2 amp./sq.dm. and strongly striated 
above this current density. Addition of 0.03 g/l Sulfoalkylsulfide No. 1 
gives a bright deposit above about 0.9 amp./sq.dm. which is still slightly 
striated in the high current density range and is semibright below 0.9 
amp./sq.dm. Only final addition of both 0.0015 g/l 2-mercaptothiazoline 
and 0.0025 g/l Pluronic F-68 gives a uniform bright and smooth copper 
deposit over the whole current density range with fair leveling 
properties. 
The effectiveness of the Amines of this invention increases if one or more 
of the three methyl groups in Amine No. 3 is replaced by higher alkyl, 
sulfoalkyl, hydroxyethyl, hydroxypropyl, hydroxyalkoxy, hydroxydialkoxy 
groups, a second benzyl group or a phenyl group. Also the linking of 2 
quaternary nitrogen atoms carrying each a benzyl group by a bivalent 
radical gives powerful additives. 
While the invention has been described and illustrated in detail, it is 
clearly to be understood that this is intended to be of example only and 
is not to be taken to be of limitation, the spirit and scope of the 
invention being limited only by the terms of the following claims.