US3542655A - Electrodeposition of copper - Google Patents

Description

Patented Nov. 24, 1970 3,542,655 ELECTRODEPOSITION OF COPPER Otto Kardos, Ferndale, Hugh B. Durham, Southfield,

Arthur J. Tomson, Novi, and Donald A. Arcilesi, Sterling Township, Utica, Macomb County, Mich., assignors to M&T Chemicals Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Apr. 29, 1968, Ser. No. 725,209

Int. Cl. C23b /20, 5/46 US. Cl. 204-52 33 Claims ABSTRACT OF THE DISCLOSURE According to 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 from each of the following groups:

(1) a polysulfide compound of the formula (2) a heterocyclic compound of the formula (JO-iL-SH and/or tautomers thereof; and

(3) a polyether, containing at least 5 ether oxygen atoms per molecule;

wherein each 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 organo group of l-20 carbon atoms, or the groups R40 M or -R(S) -RSO M wherein q is an integer 2-5; M is a cation;

R" is hydrogen or an alkyl, hydroxyalkyl or aminoalkyl group of 1-6 carbon atoms; Y is a divalent organo group of 1-10 carbon atoms which forms a '5-6-membered cyclic ring structure with the group and n is an integer 2-5 inclusive.

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 electrodeposits.

It is an object of this invention to obtain bright, ductile, leveled copper electrodeposits. A further object of the invention is to provide novel plating bath compositions from which bright copper electrodeposits may be obtained wherein said electrodeposits exhibit good leveling and ductility over wide current density ranges. Other objects of the invention will be apparent from the following detailed description.

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 from each of the following groups:

(l) a polysulfide compound of the formula R'SR-SO M x /n a (2) a heterocyclic compound of the formula i (X)-hsH and/or tautomers thereof; and (3) a polyether, containing at least 5 ether oxygen atoms per molecule;

wherein each 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 organo group of 1-20 carbon atoms, or the groups R-SO M or -R-(S) RSO M wherein q is an integer 2-5; M is a cation;

IRII X is N--, N=, S, or -0- R is hydrogen or an alkyl, hydroxyalkyl or aminoalkyl group of 1-6 carbon atoms; Y is a divalent organo group of l-lO carbon atoms which forms a 5-6-membered cyclic ring structure with the group and n is an integer 2-5 inclusive.

When several radicals R are present, the -R groups may or may not be identical. As used herein, the term leveled denotes a surface which is smoother than its substrate.

The combination of these three additives in a chloridecontaining 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. 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 be plated. The polysulfide sulfonates, as defined herein, have been found to be much more efiective when employed according to the invention than the corresponding monosulfides.

When used alone these additives may be found to be deficient in that the copper deposits obtained may not be bright, smooth, and exhibit adequate leveling properties over a sufiicient current density range. Combinations utilizing two of the additives may give fairly 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 may give striated deposits and limited bright current density ranges.

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 compositions of the invention include the following:

TABLE I Sulfate bath (1) CuS0 -5H O, 150-300 g./l. (preferably about 220 g./l.) H 50 10-110 g./l. (preferably about 60 g./l.) Cl, 5-100 mg./l. (preferably about 20-40 mg./l.).

Fluoborate bath (2) Cu(BF -600 g./l. (preferably about 224 g./l.)

HBF 1-60 g./l. (preferably about 3.5 g./l.)

3 H BO -30 g./l. (preferably about 15 g./l.) Cl, -100 mg./l. (preferably about 20-40 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. 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, including nickel alloys with other metals such as cobalt-iron; aluminum, including its alloys, after suitable pretreatment, etc.

After the deposition of the bright leveled copper deposit of this invention, generally a bright nickel deposit and a chromium deposit (which may be microporous or microcracked) may be applied. The bright 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 stress. It improves corrosion resistance and permits economy in nickel.

Because of its strong leveling properties, its very good performance at high current densities, and its very good mechanical properties the bright acid copper electrodeposits of this invention may be used for industrial applications such as the plating of printing rolls, memory drums, etc., and for electroforming. It gives very good results also for the plating of non-conducting materials, such as plastics, after the usual pretreatment.

The plating conditions for electrodeposition from the aforementioned baths may, for example, include temperatures of C.-60 C. (preferably 20 C.-40 C.); pH (electrometric) of less than about 1.5; and a cathode current density of .1-30.0 amperes per square decimeter (a./s.d.).

'Iypical average current densities may be 2-20 a./s.d. for the sulfate bath, and about 4-40 a./s.d. for the fluo borate bath. Air agitation, volume agitation, or mechanical agitation may increase the effective current density ranges and enhance the uniformity of the copper deposit.

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 from each of the following groups:

( 1) a polysulfide compound of the formula R-SOaM (2) a heterocyclic compound of the formula (X)CSH and/or tautomers thereof; and

(3) a polyether, containing at least 5 ether oxygen atoms per molecule;

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., CH -CH CH '(CH2)3 (CH2)4F 2)5' in general, (CH wherein p is an integer 1-10). R may be a divalent non-heterocyclic group of 1-10 carbon atoms containing 1-3 oxygen, 1-3 sulfur, or 1-3 nitrogen atoms (such as --CH CH OCH CH CH CHOHCI-I CH CH NHCH CH -CH CH SCH CH etc.). In the compound f R s R may be a hydrocarbon radical preferably selected from 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 branched 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, tetradecyl, octadecyl, etc. Preferred alkyl includes lower alkyl, i.e., having less than about 8 carbon atoms, i.e., octyls and lower. When R is alkenyl, it may typically be vinyl, allyl, methallyl, buten-lyl, buten-Z-yl, buten-S-yl, penten-l-yl, hexenyl, heptenyl, octenyl, decenyl, dodecenyl, tetra-decenyl, octadecenyl, etc. When R is alkynyl, it may typically be ethynyl, propargyl, butynyl, etc. When R is cycloalkyl, it may typically be cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc. When R is aralkyl, it may typically be benzyl, [3- phenylethyl, u-phenylpropyl, B-phenylpropyl, etc. When R is aryl, it may typically be phenyl, naphthyl, etc. When R is alkaryl, it may typically be tolyl, xylyl, pethylphenyl, p-nonylphenyl, etc. K may be inertly substituted, e.g., may bear a non-reactive substituent such as alkyl, aryl, cycloalkyl, aralkyl, alkaryl, alkenyl, ether, etc.

Polysulfide compounds of the formula (1) may typically be prepared by the reaction of an alkali metal salt of a hydropolysulfide and a sultone according to the reaction:

R-SOaM SSNa 2CHz-CH 1 1m l momnsoan SSNa 2011,4311,

6 sulfide (such as Na S RS H, R'S Na, wherein R is as previously defined).

Other preparative reactions may include the following:

( c) ClCH CH Cl+2NaSS (CH SO Na- NaO S (CH SSCH CH SS (CH SO Na Typical polysulfide compounds which may be employed according to the invention include the following compounds which are summarized in Table II. In the formula M represents a sodium cation and R, R, and n are as indicated in Table II.

TABLE II Sulfouated Polysulfide Cooperating Brighteners of the Formula R S RSOaNa Additive R n B CH3 I 8-3 H3C- 2 (C 2)a 5-4 ERGO 2 (CH2):

2)a aNn 3-6 IITH(CH2)3SO5H 2 (0 93 S-7 SOQNa 2 3-8 Naoas (C1102 92 8-9 NaO5S(CH2)5 H2)a 8-16 -I- NaOzS (oHms om 8-17 CHzCHzCHzCHz NNNNMNlFNNN Additive R n R S18 H C=OHCHZ 2 (CHM 8-19 HCECCHz 2 (C Z)3 S-2l 2 (CH2):

S22 NSiOaSCHzCHKOH) CH: 2 CH2CH(OH)CH3 The R(S) Na compound may be prepared by the reaction of RSNa with sulfur if R is an aromatic group (compounds 8-1, 8-2, 8-3, S4, 8-5, -20). A typical procedure is: To a methanol solution (150 ml.) containing sodium methoxide (0.1 m.) is added the RSH (0.1 m.) compound. The mixture is stirred at room temperature until the compound has dissolved. Sulfur powder (0.1 m.) compound. The mixture is stirred at room temuntil all the sulfur is dissolved. Propanesultone (0.12 m.) 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 filtered, washed with acetone, and dried.

Aliphatic R'(S),,Na compounds are prepared by reaction of R'Q with Na S where Q is Cl, Br, I, OSOZCGH5, --OSO2C6H4'CH3, Compounds S-l7, 5-18, 5-19). A typical procedure is: To a stirred methanol solution (150 ml.) containing sodium di sulfide (0.1 m.) is added dropwise a solution of RQ (0.1 m.) in methanol (50 ml.) at room temperature. The reaction is slightly 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 white solid usually precipitates from the solution. The mixture may be heated and stirred at 65 C. for 30 minutes and then cooled. Acetone is added and the solid is filtered and dried.

Compounds of the type of 8-9, 8-10, S-ll, 8-12 are prepared by the reaction of an alkali metal polysulfide (Na s Na S etc.) with a sultone.

Compounds of the type of 5-13, 8-14, 8-15, 8-16 are prepared according to the reaction sequence:

NaSzRSzNa 2 ICH CH CH NaOaS(CHz)aSzR S2 CHz)3S OaNa Instead of sultones, haloalkane sulfonates, including, e.g., ClCH CHOHCH SO Na (prepared by reaction of epichlorohydrin with sodium bisulfite), and in general compounds of the type QRSO M, may be used.

Some polysulfide compounds may also be prepared by the direct sulfonation of an organic polysulfide (e.g., S-7; or 8-21 by sulfonation of 8-20).

Symmetrical disulfides may be prepared by careful oxidation of compounds of the type HSRSO Na.

It is sometimes advantageous to prepare aqueous stock solutions of the sulfonated polysulfides containing small amounts of 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 copper bath in eifective amount of about 0.001 g./l. 1.0 g./l., preferably 0.005 g./l.0.2 g./l.

The heterocyclic cooperating additives of the invention may include heterocyclic compounds of the formulae:

(1 (Y)NH (Y)N (X) The two formulae represent tautomeric forms wherein X is selected from the group consisting of B? N--, N=, S, or O- R" is hydrogen or an alkyl, hydroxyalkyl, or aminoalkyl group of l-6 carbon atoms and Y is a divalent organo group of 2-10 carbon atoms which forms a 5-6-membered cyclic ring structure with the group -N=C-X- or the group H s I I X- Typical X groups may include groups of the formula R CH3 CHgCH NH; CHzOHzNCHa I% such as: I I, IG- I LI- CH3 CH2OHZN/ I I- CH2 When Y is a divalent hydrocarbon group (including substituted hydrocarbon groups) Y may be a divalent alkylene group of 2-10 carbon atoms (such as an ethylene, propylene, etc., including alkyl-substituted divalent groups); Y may be an unsaturated group of 2-10 carbon atoms, and an amino or hydroxy-substituted saturated or unsaturated hydrocarbon of 2-10 carbon atoms.

Typical heterocyclic compounds which may be employed according to the invention may include compounds of Table 111 wherein the groups X and Y of formulae (1) and (2) are as shown. The heterocyclic compounds may be employed in eifective amounts, typically 0.5l0.0 mg./l. and preferably 0.7-4.0 mg./l. of total aqueous bath composition.

TABLE III.-HETEROCYOLIC GOOPERATING AGENTS (Y)NH (Y)N 1) 2 (X)-- :8 QO-(il-SH Additive (X) (Y) Structure Name H-l S- CHzCIh- HI Z-thiazolidinethlone. s SH Additive (X) (Y) Structure Name r r H-m N= =CCH=C-- NH 4,G-dimethyl-2-pyrimidlnethlol.

HG l=s Eel Ls];

11-11 N= =CHCH=CH- NH N 2-pyr1midinethiol.

J 2 J' \\N =s \N SH ii H-18 -NH GCH=CH- NH N 2-thiouracil.

i J o s HO -s 1 OH fl) fl [I I 11-19 N -CCH2-C- NH A 2-thiobarbituric acid.

H i 0 s H0 )sn The heterocyclic cooperating additives of Table III may be obtained commercially or may be prepared as indicated herein. For example, compounds such as H-1 and H-4 may be prepared according to equation:

H- may be prepared from ethanolamine and carbon disulfide, which by oxidation with iodine gives bis-(2-hydr0xyethyl-)thiuram disulfide. Boiling of an aqueous suspension of this compound yields H-S.

Compounds such as H-l, H-2, H-4 may also be prepared by heating of the alkanolamine-carbon disulfide reaction product according to the equation:

Polyethers which may be used according to the process of the invention may have at least 5 ether oxygen atoms and include polyethers of the formulae:

z RIIII(N Z Ill where R is a monovalent radical such as H, alkyl, alkenyl alkynyl, alkylaryl, arylalkyl or a heterocyclic radical; and R" is a mvalent aliphatic, aromatic or heterocyclic radical; m=2 to and where u and v =0 to 4, but at least one of u or v must be greater than zero; r+s=6 to 1000; and T=H, alkyl, benzyl, 403M, C H2 SO3M, PO3H2.

Suitable polyethers which may be used according to the invention include polyethers set forth in Table IV.

. The polyether additives may be employed in elfective amounts, typically 0.005-l0.0 g./l. and preferably 0.1- 1.0 g./l. of total aqueous bath composition.

Additive P15 CH3 CH C zC al J-CH:CHz( l-CH:CHa

5 (IJHCHQ HUH IE2 IE3 u n 3H: JHI (:lH: (:JH; i m I m zn fil out 12-15 P-16 C1zHz5S(CH2CH2O)zo 17 CH3(CH3)5CHCH1 0 (C HsO)2(C2H4O)2nH P-18 CHr(CH2)1O (C2H40)2o(CaHu02) P-19 CH3(CH2)11O (C2 4O)zo(CzHu0)z P-20 H(OH4C2)15O (CHzhoO (O2 40)l5 P-21 H(O CzH|)a CH: C CI AON NCHzl-CHr-JH-CHr-CBHN H(OH4C2): CHI C2H|O)sH The chloride ion content of the aqueous copper plating bath compositions of the invention may be at least about 0.5 mg./1. and typically from 1.0 mg./l. to 500 mg./l. of

aqueous copper plating bath. Good results may be obtained using a chloride ion concentration of from about 4 mg./l. to 60 mg./1. of aqueous copper plating bath composition, and preferably a chloride ion concentration of from 20 mg./l. to 60 mg./l. of aqueous copper plating solution.

Other optional additives used were the following dispersing agents:

For the purpose of provding those skilled-in-the-art with a better understanding of this invention, the following examples are set forth.

In these examples the aqueous copper plating bath contains:

CuSO .5H O, 220 g./l. H 80 g./l. Chloride ion, 0.03-0.04 g./l.

The plating experiments were performed in a Hull Cell containing 250 ml. of this acid copper sulfate bath. The

wherein each n is an integer 4-12 refer-ably 4-8) and each of M1 and M: is an alkali metal (preierably Na or K? or a hydrogen atom.

Hull Cell allows one to observe the appearance of the deposit over a wide current density range. In order to Amount, Type of Additives g./l. agitation Results udge the degree of leveling the polished brass panels 02 used for these plating tests were scratched with 4/0 11 {P-u 0.1 }Air Very good. emery polishing paper over a horizontal band of about r 51- 8; D 10 mm. width. The plating temperature used in these 0 12 01 0 8-1 0.02 experiments was the ambient room temperature (24-30 13 1H3 0.20 Air Very good. 0.), unless otherwise stated. The total current was 2 H-1 0.001 amperes and the plating time 10 minutes. Air agitation 14 @1 }Air Poor. or mechanical agitation with an oscillating paddle was 10 s-2 0. 03 use as specified in Table VI. The sulfonated polysulfide 15 31 2 D0 compounds used are described in Table H, the heteros-a 0.03 cyclic compounds in Table III, and the polyethers in 16 1 3532 Air Good Table W. 11-7 0. 00075 For convenience, the results shown in Table VI are 15 @1 F classified according to (1) the width of the lustrous 17 H-l 0.00075 Air Excellent. current density range (semi-bright to bright) and accordg1 8918 ing to (2) the degree of leveling under the indicated ex- 18 .{s4 0. 03 p POOL perimental conditions (i.e., a 250-ml. Hull Cell, 2 5: 8g amperes current, and a ten-minute plating time on a 20 i0 P-l 0 1.00 Good metal strip having a band uniformly scratched with 4/0 iii grit emery paper). 20 @1 1 }Air Poor.

Each property in groups (1) and (2) is independently 1 measured as poor, fair, good, and very good as 21 1 0 3g Air 0 very good, follows: 11-7 0. 00075 Property (1) pe y Rating Width of lustrous current density range Rating Degree of leveling Poor Less than one half of length of test panel Poor No visual change in original roughness of scratched band Fair More than onehalf andless than two thirds of length oitestpanel Fair Ntg ig e a l i le decrease in roughness. but scratches still Good More than two thirds but less than entire length of test pane1 Good Rtiughlne ss decreased andportions of scratches completely 8V6 Very good... Entire length of test panel is lustrous Very good... Scratches on the portion of the panel having a current density greater than 2.5 a./s.d. are practically invisible.

The combination of the panel ratings given with re- Amount, Type of spect to width of lustrous current density range and de- Additives g./l. agitation Results gree of leveling determine the final classification set forth 0 03 1 in the Results column of Table VI according to the 4 1,00 following: 22 5; 3333;; Air Excellent- D-l 0.4 Results Definition 23 "@1 3'83 }Air Poor. Excellent-.- Very good leveling and very good bright current density 3-6 03 range. 24 P4 L00 Air Good. Very good... Very good leveling and good bright current density range. H4 88 Good Good to very good leveling and good to very good semi- 7 .0 bright Olll'gllt ggnsity ratnge or good levehng and good to 00 very goo rig curren ensl yrange. I Poor Poor leveling and/or poor lustrous current density range. 25 H4 88 Very good- Fair All intermediate panels not otherwise classified. gg 0 2 26 8-7 0.05 Meclganicalu Poor. TABLE VI 28 0.20}. 0 Do. A yp p 3 3: Additives g./l. agitation Result 29 Good H-1 0.001 Exam 10 No.2

1 P S-1 0. 03 MI 30 gg}... -oo Pool ga 8g s-7 0:05 2 P-l 1100 }Alr Good. 31 "{gf f}"--- 11-1 0. 001 b 20 S-1 0. 03 32 .-do Poor 3 "[21 1 0 53? Air Excellent 33 g 3-3} G G d O O0 E 1 8-62 g; P-l 1. 00 34 do..-- Poor. 4 114 0 000625 GOOd- 1 2 g? 0 g gg 35 ..{P12 0 5}.-. do Good. 1 00 11-1 0. 001 5 H-l 0.000625 Air Excellent. 36 "@1 Air Poor.

ti mtg? its 6 "@1 Mechanical Poor. 37 11-1 0. 00075 Very s-1 0. 02 j 8 53 7 P-g 1.00 --..do V y geod- P4 1 8; 33 H-l 0.00075 Air D0. 8 Air Poor. 11-7 0. 00075 P-11 0.1 a 4 s-s 0. 02 9 P-ll 0.1 Air Fair. 39 L00 Air Poor. a as; 1o }Air F 40 1 1 9 Air Good Amount, Type of Additives g./l. agitation Results a 41 H4 (L601 Air Good. 5

42 Air Poor. 43 s-o 0.02

------- P-l 1. 00 Air..... Good.

2 68? Air Excellent. D-2 0. 40 45 i i 00 2-5 46 H4 0000025 Air Excellent.

------------ P-1 1.00 Air. Good.

------------ P-r 1. 00 Air.......... Very good.

All Excellent.

1 0. s-e 0.02 "{P-l 1. 00 Air Very good.

H-5 0.002 8-9 0.02 51 1 83 Air Excellent.

9 .0 52 00} Air Good.

5 5 033 53 :00} Air G od- H-7 0.002 as 54 1. 11-7 0.002 30 D-l 00.04 S-9 2 55 --{p 1 1,00} Air Very good.

11-!) 0. 002 8-9 0.02 50 --{P1 1.55} A o.

9 57 --{p 1 00} Air D0.

H-13 0.0080(2); S-9 58 00} All Good H-14 ObOg; "E3 1 Air Do 45 g-lfi 0.

9 --{1 1 1. 00} Air ISH16 0. 61 1:00 A l D0.

gr- 1s 5O 02 M 8 3; echamcal Poor 63 "$33; 0: d0 Excellent.

"as; 05 -9 11' P P12 0. (1)0 A cor 66 "E1 81 Air Very good.

H-1 0. 001 07 S-9 0. Air Fair,

1 -13 006% 6s $53 i Air Excellent.

22-: 0 a 6 Air P 9 P13 .00 70 "$3 18$}A1r 0005.

be 8-10 Air P 71 P-I 1. 00} 72 F1 183 Air Very good.

H-1 0.001 73 5-11 0. 02 Air P001;

s 74 N P21 120 A Good- H7 0.002 8-11 0. 02 75 P-l 1.00 Air Do.

, Amount, Type of Addmves -li. agitation Results S13 Ai Poor. 5?; 3a 77 {P12 1 A Good.

11-1 0. 001 78 {5-1 0.01 Air Poor.

P-14 0, 0 79 "F 5; 8:25 A l Excellent.

H-1 0. 001 80 8-16 0.005 Air F i 0 .32 1 P-1 '1, 00 r A r Good ir V d. 32 H42 H01 A y 5 0 A Poor. 83 5-1 5-22 34 P 10 1:00 A Very good.

H44 0. 001 35 2%; Mechanical Poor.

l8 86 {P8 1.00 Very good.

H-l 0.0031 s-19 2 87 g Air Fair 19 88 P-10 1,00 Air Very good.

.1 s9 5 Air Fair.

19 90 P-14 1,00} Air Very good.

H-l ObOg S-20 01 H2 8g} Air Fair.

5-20 0. 92 P-12 0.50 Air ..Excellent.

a S-21 93 P-M 0,50 Fair 5-21 0.30 94 P-M 0.50 A11 Very good' H-l S-22 95 Air Fair.

S-22 0 04 06 P-12 0. 50 Air Very good.

1 At 46 C.

As can be readily seen from above examples of Table VI, the combination of an aromatic or aliphatic polysulfide sulfonate (compounds S of Table II) and of a polyether (such as the compounds P of Table IV) generally gives matte deposits in the low and medium current density range and/or the degree of leveling over a rough substrate is low.

Addition of at least one heterocyclic compound (H) of the type described in Table III to the combination of S and P very strongly increases leveling and widens the bright current density range toward lower current densities. The addition of a compound (H) often increases also the intensity of brightness.

Results similar to those reported in Table VI (wherein a copper sulfate bath was used) may be obtatined with a fluoborate bath using higher current densities and somewhat higher concentrations of the heterocyclic compounds, (H). For instance, using a fluoborate electrolyte containing:

Cu(BF 224 g./l. HBF 3.5 g./l. H BO 15.0 g./l. Cl-, 0.03 g./l.

The simultaneous addition of:

5-9, 0.02 g./l. P-l, 1.00 g./l. H-1, 0.001 g./l. H-7, 0.001 g./1.

gave a bright, strongly leveled copper deposit in an air agitated Hull Cell (250 ml.) at 5 amperes total current in 5 minutes, up to the high current density end of the cell (about 30 a./s.d.).

R-SOaM in effective amount of 0.001 g./l.-1.0 g./l.

(2) a heterocyclic compound of the formula and/or tautomers thereof in effective amount 0.5- 10.0 mg./l.; and

(3) a polyether, containing at least 5 ether oxygen atoms per molecule in effective amount of 0.005- 10.0 g./l.

wherein each 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 organo group of 1-20 carbon atoms, or the groups RSO M or R(S) RSO M wherein q is an integer 2-5; M is a cation;

Br]! X is -N-, -N=, s, or o- R" is hydrogen or an alkyl, hydroxyalkyl or aminoalkyl group of 1-6 carbon atoms; Y is a divalent organo group of 1-10 carbon atoms which forms a 5-6 membered cyclic ring structure with the group and n is an integer 2-5 inclusive.

2. The process as claimed in claim 1 wherein n is an integer 2-4.

3. The process as claimed in claim 1 wherein n is an integer 2-4, R is an aromatic group, and R is a polymethylene group.

4. A process as claimed in claim 1 wherein the polysulfide compound is of the formula in which R is NaO S(CH n is 2; and R is (CH-Q 5. A process as claimed in claim 1 wherein the polysulfide compound is of the formula in which R is NaO S(CH S (CH n is 2; and R is 2)3- 6. A process as claimed in claim 1 wherein the polysulfide compound is of the formula in R, is n is 2; and R is (CH2)3.

7. A process as claimed in claim 1 wherein the polysulfide compound is of the formula RSOaNa RS OaNa RS}ft s O Na in which R is NaO S(CH S CH C=CCH n is 2; and R is 8. A process as claimed in claim 1 wherein the polysulfide compound is of the formula in which R is NaO S(CH S (CH n is 2; and R is 2):;-

9. A process as claimed in claim 1 wherein the polysulfide compound is of the formula A in which R is H C=CHCH n is 2; and R is (CH 10. A process as claimed in claim 1 wherein the polysulfide compound is of the formula J. in which R is HC'=CCH n is 2; and R is (OH 11. A process as claimed in claim 1 wherein the polysulfide compound is of the formula f R S in which R is NaO SCH CH(OH)CH n is 2; and R is CH CH(OH)CH 12. A process as claimed in claim 1 wherein X is S-. 13. A process as claimed in claim 1 wherein X is O. 14. A process as claimed in claim 1 wherein X is 15. A process as claimed in claim 1 wherein X is- CH2CH2OH 16. A process as claimed in claim 1 wherein Y is -CH CH 17. A process as claimed in claim 1 wherein the chloride ion concentration is at least 0.5 mg./l. of total aqueous bath composition.

18. A process as claimed in claim 1 wherein the chloride ion concentration if 1-500 ing/1. of total aqueous bath composition.

19. A process as claimed in claim 1 wherein the polyether is RSOaNa RSOaNa RSOaNa Ill-{41:30, and wherein the process is carried out in the presence of a dispersing agent of the formula 20. A process as claimed in claim 1 wherein the polyether is H(O2H40)y(O3HBO)x N CHzCHzN (C2H4O) (Ca GO)= (C3 6 )X( Z 4o)yH wherein x is about 3 and y is about 3-4.

21. A process as claimed in claim 1 wherein the polyether contains oxypropylene and oxyethylene groups.

22. A composition for electrodepositing bright, strongly leveled, ductile copper which comprises an aqueous acidic copper plating bath containing chloride ions and at least one member from each of the following groups:

(l) a polysulfide compound of the formula in effective amount of 0.01 g./l.-1.0 g./l. (2) a heterocyclic compound of the formult and/or tautomers thereof in effective amount of -100 mg./l.; and

(3) a polyether, containing at least 5 ether oxygen atoms per molecule in effective amount of 0.005- 10.0 g./l.

wherein each 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 organo group of 1-20 carbon atoms, or the groups RSO M or -R-(S),, --RSO wherein q is an integer 2-5; M is a cation;

R" is hydrogen or an alkyl, hydroxyalkyl or aminoalkyl group of 1-6 carbon atoms; Y is a divalent organo group of 1-10 carbon atoms which forms a 5-6 membered cyclic ring structure with the group 24 28. A composition as claimed in claim 22 wherein X is CH2CH2OH 29. A composition as claimed in claim 22 wherein Y is CH CH 30. A composition as claimed in claim 22 wherein the chloride ion concentration is at least 0.5 mg./l. of total aqueous bath composition.

31. A composition as claimed in claim 22 wherein the chloride ion concentration is 1-500 mg./l. of total aqueous bath composition.

32. A composition as claimed in claim 22 wherein the polyether is in O n l m+n=30, and containing a dispersing agent of the formula CH2/@3 S OaNa 33. A composition as claimed in claim 22 wherein the polyether is References Cited UNITED STATES PATENTS 2,663,684 12/1953 Pierce 20452 2,700,020 1/1955 Pierce 20452 2,840,518 6/1958 Condon 204-52 3,267,010 8/1966 Creutz et al. 20452 3,288,690 11/1966 Creutz et al. 20452 3,328,273 6/1967 CreutZ et al 20452 GERALD L, KAPLAN, Primary Examiner