Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3502551 A
Publication typeGrant
Publication dateMar 24, 1970
Filing dateAug 10, 1967
Priority dateAug 20, 1966
Also published asDE1521031A1, DE1521031B2
Publication numberUS 3502551 A, US 3502551A, US-A-3502551, US3502551 A, US3502551A
InventorsClauss Wolfgang, Todt Hans Gunther
Original AssigneeSchering Ag
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Acid electrolyte for the deposition of bright,levelling copper coatings
US 3502551 A
Abstract  available in
Images(3)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent 3,502,551 ACID ELECTROLYTE FOR THE DEPOSITION OF BRIGHT, LEVELLING COPPER COATINGS Hans Gunther Todt and Wolfgang Clauss, Berlin, Germany, assignors to Schering AG., Berlin, Germany No Drawing. Filed Aug. 10, 1967, Ser. No. 659,608 Claims priority, applicatigr; (iermany, Aug. 20, 1966,

Int. Cl. C2241 1/1 6; C231) 5/18, 5/46 US. Cl. 204-52 6 Claims ABSTRACT OF THE DISCLOSURE wherein R is the amino group or its functional derivative, or a heterocyclic radical combined through a nitrogen atom, and possibly containing additional hetero atoms, and n is an integer ranging between about 5 and 1000.

This invention relates to an acid electrolyte for the deposition of bright leveling copper coatings. An object in particular is to improve electrolytic deposition from aqueous acid solutions of copper salts.

It has long been known that certain organic substances can be added in small quantities to acid, particularly the most widely used sulfuric acidcopper electrolytes, in order to obtain bright copper coatings instead of a crystalline-dull deposition. Thus, there has been proposed, for example, the use of organic thio compounds, such as thiourea, thiohydantoin, thiocarbamic acid esters, thiophosphoric acid esters and many derivatives of these compounds. However, these substances have many disadvantages, which have led to their being no longer used for modern bright copper baths. In addition, the ductility of the copper coating is greatly reduced and the uniformity of the film thickness distribution is reduced. Also in certain current density ranges, the deposit shows black streaks or is of the nature of a relief.

For the purpose named, there have further been proposed, in recent times, compounds which contain in the molecule not only one or more sulfur atoms of double negative charge but also one or more sulfonic acid groups or other water-solubilizing groups. These compounds are described in German Patents Nos. 1,037,801, 1,168,208, 1,196,464 and 1,201,152. If used alone, however, these compounds have no longer any luster effect in acid copper baths, or'there is a limited duster effect only at high concentrations, at which the mechanical properties of the copper precipitates are so negatively influenced, however, that their practical use is no longer possible.

Only if these compounds, e.g. thioalkane sulfonic acids or thiophosphoric acid esters with water-solubilizing groups, are added to the copper electrolyte together with certain high-molecular substances does one obtain, as can be shown, bright copper precipitates. As high-molecular substances there enter into consideration for this, for example, fatty alcohol-ethylene oxide addition products, nonyl-phenol-ethylene oxid addition products, polyethylene glycols and similar compounds. These combinations, too, however, do not meet the increased requirements of the practice, as their leveling effect is too small and polishing streaks or faults in the base material are still clearly visible after the copper-plating, so that additional mechanical treatment is necessary. But since, as is known, all additional polishing involves high costs, the practice increasingly demands leveling electrolytes with which the polishing costs can be reduced to a minimum.

It has now been found that the leveling effect of acid copper baths, containing as luster former oxygen-containing high-molecular compounds and organic thio compounds, can be substantially improved by adding to them one or more compounds of the general formula:

wherein R is the amino group or its functional derivatives or a heterocyclic radical combined through a nitrogen atom and possibly containing additional hetero atoms, and n is an integer between about 5 and 1000. More specifically, R is bound to said (CH CH) by a carbon-nitrogen bond and is the radical of a base selected from the group consisting of ammonia, dimethylamine, acetamide, thioethylurethane, carbamic acid, thiourea, succinimide, imidazole, N,N'-ethyleneurea, pyrollidone- (2), morpholine, morpholinone-(3), benzibidazol, 5- alkyloxazolidone-(Z), and caprolactam.

The additions to be used according to the invention are polyvinyl amine and its functional derivatives as Well as N heterocyclic polyvinyl compounds. These are known per se and can be produced in a manner known in the art. Polyvinyl amine, for example, is formed by acid or alkaline saponification of cyclic N-vinyl imides, such as N-polyvinylphthalimide, as disclosed in US. Patent 2,484,423, or by saponification of poly-ethyl-N-vinyl carbamate, as disclosed in German Patent 865,901.

N-polyvinylacetamide is obtained, for example, by acylation of polyvinyl amine with acid chloride or acid anhydride by generally practiced methods disclosed in US. Patent 2,507,181.

N-polyvinyl carbamates (-N-polyvinyl carbamide esters) are formed, for example, by polymerization of vinyl isocyanates with alcohols in the presence of azoisobutyric acid dinitrile, as disclosed in Belgian Patent 540,975.

N-polyvinyl pyrrolidone, as disclosed in German Patent 922,378; N-polyvinyl morpholinone-(3), as disclosed in British Patent 849,038; and N-polyvinyl-S-alkyl-oxazolidone-(2), as disclosed in US. Patent 2,946,773, can be prepared from the respective monomers, as by polymerization in solution in the presence of azoisobutyric acid dinitrile.

Naturally, these compounds are present in the copper bath as salts, for example as sulfates in the usual sulfuric acid electrolytes, but they may alternately be added in salt form, such as hydrochloride, methyl iodide, ethyl bromide, etc.

It is already known from German Patent 933,843 that polyvinyl amine or polyvinyl pyrrolidone are added to galvanic baths, namely in quantities between 0.02 and 1.0 g./liter. If used alone, however, as has been found, they do not achieve any luster effect or leveling in acid copper baths. The precipitate is merely fine-grained,

smooth, and free from streaks. However, it thereby does not in the least fulfill the requirements that bright copperplating must meet today. There is in this patent no reference to the surprising fact that these substances can drastically improve the leveling effect if they are added to copper electrolytes which contain oxygen-containing highmolecular compounds and organic thio compounds.

The quantities needed for a marked improvement of the copper deposition, in particular of the leveling effect are extremely small, ranging from between 0.0005 and 0.1 g./liter, generally 0.0005 to 0.03 g./liter, depending on which basic luster former the copper bath contains.

Generally, there is used as the electrolyte a sulfuric acid copper sulfate solution of the following composition g./liter Copper sulfate CuSO -5H O 125-260 Sulfuric acid H 80 2085 Instead of copper sulfates, other copper salts may be used at least in part. The sulfuric acid may be replaced in part or wholly by fiuoroboric acid, phosphoric acid, or other acids. The electrolyte may be chloride free or, and this is advantageous for improvement of the luster, contain chlorides, e.g. alkali chlorides in quantities of 0.001 to 0.2 g./liter. As additional additives, other common lusters formers and/or wetting agents may be used.

Below are listed in Table 1, by way of example, substances which, according to the invention, are added to acid copper baths with oxygencontaining high-molecular compounds and organic thio compounds to obtain highgloss copper precipitates with increased leveling effect.

TABLE 1 Preferred concen- Substance: tration, g./liter (1) Polyvinyl amine 0.0050.0-2 (2) N,N-dimethyl-polyvinyl amine 0.005-0.03 (3) N-polyvinyl acetamide 0.005-0.03 (4) N-polyvinylthioethyl urethane 0.0005-0.005 (5) N-polyvinyl carbamate 0.001-0.02 (6) N-polyvinyl thiourea 0.00050.005 (7) N-polyvinyl succinimide 0.005-0.02 (8) N-polyvinylimidazole 0.010.03 (9) N-polyvinyl-N,N'-ethylene urea 0.02-0.07 (10) N-polyvinyl pyrrolidone-(Z) 0.001-0.01 (11) N-polyvinyl morpholine 0.005-0.05 (12) N-polyvinyl morpholinone-(3) 0.0010.0'2 (13) N-polyvinyl benzimidazol 0.001-0.005 (14) N-polyvinyl 5 alkyl oXazolidone-(2) 0.001-0.01 (15) N-polyvinyl caprolactam 0.0005-0.002

Known copper electrolyte additions on the basis of oxygen-containing high-molecular compounds and organic thio compounds which contain preferably one or more water-solubilizing groups are listed in Tables 2 and 3 which, when used alone, do not develop a luster effect and when used jointly show an unsatisfactory leveling. The quantities which are added to the copper electrolyte are approximately within the following limits:

Oxygen-containing high-molecular compounds 0.01-1O g./liter, preferably 0.02-5 g./liter Organic thio compounds with water-solubilizing groups 0.0020.2 g./liter, preferably 0.005-0.1 g./liter TABLE 2 Preferred concen- Substance: tration, g./liter 1) Polyvinyl alcohol 0.05-.4 -(2) Carboxymethyl cellulose 0.05-0.1 (3) Polyethylene glycol 0.05-0.5 (4) Polypropylene glycol 0.01-0.2 Stearic acid polyglycol ester 0.5 5.0 (6) Oleic acid polyglycol ester 0.5-5.0 (7) Steryl alcohol polyglycol ether 05-50 (8) Nonylphenol polyglycol ether 0.52.0

TABLE 3 Preferred concen- Substance: tration, g./liter (l) Dithiophosphoric acid 0,0-diethyl- S (omega-sulfopropyl)-ester, sodium (7) Thioglycolic acid 0.001-0.003

If the compounds of Tables 2 and 3 are used together with one or more substances of Table 1 in acid copper electrolytes, there is obtained a distinct and drastic improvement of the leveling effect. The mixture ratios of the individual components may vary within wide limits. It has proved to be favorable, if there is a ratio by weight of the substances listed by Way of example in Tables 1, 2 .and 3 of approximately 1:102 to approximately 1:200:20. As further additions, the electrolyte may contain other known luster formers, such as thiourea or its derivatives, dithiocarbarnic acid esters, thiosemicarbazones, phenazine dyes, or alkaloids.

The following examples are illustrative of the invention, although not limited thereto.

EXAMPLE 1 To a copper bath of the composition:

g./liter Copper sulfate (CuSO -5H O) 200 Concentrated sulfuric acid 55 Sodium chloride 0.05

there are added as luster formers g./liter Stearyl alcohol-polyglycol ether 2.0

Sodium salt of dithiophosphoric acid, 0,0-diethyl-S-(omega-sulfopropyl) ester 0.08

At a temperature of 20-25 C., the electrolyte with a current density of an average of 4.0 a./sq. dm. and with cathode movement, bright copper precipitates are indeed obtained, but the leveling of the wrinkles of the base material is only 46% at a film thickness of 24 millimicrons. If additionally, 0.005 g./liter of N-polyvinyl pyrrolidone-(Z) is charged in the bath, the leveling increases to under the same operating conditions, an apparent increase of 63%.

EXAMPLE 2 To the elecrolyte according to Example 1, there are added g./liter Polyethylene glycol 0.1 Sodium 3-mercaptopropane-l-sulfonate 0.03

Under the same operating conditions as in Example 1, the leveling effect at a film thickness of 24 millimicrons copper is about 50%. By an addition of 0.01 g./liter N-polyvinylamine, the leveling increases to 83%, so that the increment is 66%. An equally great improvement of the deposition is obtained if one adds to the copper bath, instead of the polyvinyl amine, 0.02 g./liter N-polyvinyl imidazole or 0.004 g./ liter of an N-polyvinyl- 5-alkyl-oxazolidone-( 2) Similarly, excellent effects can be attained with the joint use of the other substances listed in Table 1 with the compounds of Tables 2 and 3.

From the foregoing description and the illustrative examples of the invention, it will be noted that there is provided a novel combination of ingredients which substantially improve the leveling effects of acid copper baths.

Furthermore, while illustrative examples are given, it is to be noted that changes as to components and ingredients in the acid baths may be made without departing from the spirit and scope of the invention as claimed.

What is clarned is:

1. In an acid electrolyte for the deposition of bright copper containing as brighteners a member of a first group consisting of polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol, polypropylene glycol, stearic acid polyglycol ester, oleic acid polyglycol ester, stearyl alcohol polyglycol ether, and nonylphenol polyglycol ether, and a member of a second group consisting of the sodium salt of dithiophosphoric acid 0,0-diethyl-S-(omega-sulfo-propyl)-ester, the disodium salt of thiophosphoric acid O-ethyl-bis -(omega-su-lfopropyl)- ester, the trisodium salt of thiophosphoric acid tri-(omegasulfopropyl)-ester, sodium 3-mercaptopropane-1-sulfonate, the sodium salt of N,N-diethyl-dithiocarbamic acid (omega-sulfopropyl)-ester, sodium Z-mercaptobenzothiazol-5-propanesulfonate, and thioglycolic acid, the improvement which comprises:

(a) an additional brightener of the formula:

azole, N.N-ethyleneurea, pyrollidone-(Z), morpholine, morpholinone-(S), Benzimidazol, 5- alkyloxazolidone-( 2) and caprolactam;

(b) said additional brightener being present in said electrolyte in an amount sufficient to produce a leveling effect on the deposited copper.

2. In an electrolyte as set forth in claim 1, the amount of said additional brightener being between 0.0005 and 0.1 gram per liter of said electrolyte.

3. In an electrolyte as set forth in claim 2, the amount of said additional brightener being not greater than 0.03 gram per liter.

4. in an electrolyte as set forth in claim 3, said mem ber of said first group being present in said electrolyte in an amount of 0.02 to 5 grams per liter, and said member of said second group being present in said electrolyte in an amount of 0.005 to 0.1 gram per liter.

5. In an electrolyte as set forth in claim 2, said member of said first group being present in said electrolyte in an amount of 0.1 to 10 grams per liter, and said member of said second group being present in said electrolyte in an amount of 0.002 to 0.2 gram per liter.

6. A process for depositing bright copper coatings on an object wherein an object is made the cathode in the electrolyte set forth in claim 1.

References Cited UNITED STATES PATENTS 2,849,351 8/1958 Gundel et al. 20444 2,853,444 9/1958 Pye etal. 204108 2,872,346 2/1959 Miller 20444 2,931,760 4/1960 Westbrook 20452 3,322,657 5/1967 Sassenroth et al 20452 DANIEL E. WYMAN, Primary Examiner C. F. DEES, Assistant Examiner US. Cl. X.R. 106l; 204106.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2849351 *Jul 8, 1954Aug 26, 1958Dehydag GmbhElectroplating process
US2853444 *Oct 18, 1955Sep 23, 1958Dow Chemical CoElectrowinning of metals
US2872346 *May 21, 1956Feb 3, 1959Adolph MillerMetal plating bath
US2931760 *Sep 25, 1957Apr 5, 1960Westbrook Leon RAcid copper plating
US3322657 *May 11, 1964May 30, 1967Langbein Pfanhauser Werke AgElectrodeposition of bright copper
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3725220 *Apr 27, 1972Apr 3, 1973Lea Ronal IncElectrodeposition of copper from acidic baths
US3743584 *Jun 2, 1971Jul 3, 1973Schering AgAcid bright copper plating bath
US3767539 *Oct 4, 1971Oct 23, 1973Schering AgAcid galvanic copper bath
US3770598 *Jan 21, 1972Nov 6, 1973Oxy Metal Finishing CorpElectrodeposition of copper from acid baths
US3770599 *May 24, 1971Nov 6, 1973Oxy Metal Finishing CorpAcid zinc plating baths
US3865744 *Mar 22, 1972Feb 11, 1975Robert AlexanderMethod of producing copper and composition therefor
US3961028 *Dec 17, 1974Jun 1, 1976Anumin Pty. LimitedMethod of producing cuprous sulfate and bisulfate solutions
US3966890 *Dec 17, 1974Jun 29, 1976Anumin Pty. LimitedMethod of producing solutions containing cuprous ions
US4113848 *May 14, 1976Sep 12, 1978Anumin Pty. LimitedMethod of producing solutions containing cuprous ions
US4376685 *Jun 24, 1981Mar 15, 1983M&T Chemicals Inc.Acid copper electroplating baths containing brightening and leveling additives
US4604175 *Jun 18, 1984Aug 5, 1986Naumov Jury IProcess for regeneration of iron-copper chloride etching solution
US5151170 *Dec 19, 1991Sep 29, 1992Mcgean-Rohco, Inc.Acid copper electroplating bath containing brightening additive
US5232575 *May 31, 1991Aug 3, 1993Mcgean-Rohco, Inc.Polymeric leveling additive for acid electroplating baths
US5730854 *May 30, 1996Mar 24, 1998Enthone-Omi, Inc.Alkoxylated dimercaptans as copper additives and de-polarizing additives
US6425996 *Dec 17, 1998Jul 30, 2002Atotech Deutschland GmbhWater bath and method for electrolytic deposition of copper coatings
US7037379 *Feb 23, 2005May 2, 2006For Your Ease Only, Inc.Anti-tarnish aqueous treatment
US7220347 *Jul 15, 2005May 22, 2007C. Uyemura & Co., Ltd.Electrolytic copper plating bath and plating process therewith
US8114263Mar 1, 2006Feb 14, 2012Atotech Deutschland GmbhPolyvinylammonium compound, method of manufacturing same, acidic solution containing said compound and method of electrolytically depositing a copper deposit
US8262891 *Oct 2, 2006Sep 11, 2012Rohm And Haas Electronic Materials LlcLeveler compounds
US8506788Sep 11, 2012Aug 13, 2013Rohm And Haas Electronic Materials LlcLeveler compounds
US8679317May 21, 2007Mar 25, 2014C. Uyemura & Co., Ltd.Copper electroplating bath
CN1940146BSep 28, 2006May 12, 2010罗门哈斯电子材料有限公司Leveler compounds
CN100595343CJul 22, 2005Mar 24, 2010上村工业株式会社Electrolytic copper plating bath and plating process therewith
CN101935854A *Sep 20, 2010Jan 5, 2011东莞华威铜箔科技有限公司Preparation method of additive for electrolytic copper foil, product and application thereof
CN101935854BSep 20, 2010Nov 30, 2011东莞华威铜箔科技有限公司Preparation method of additive for electrolytic copper foil, product and application thereof
DE2746938A1 *Oct 17, 1977Apr 19, 1979Schering AgSaures galvanisches kupferbad
DE3836521A1 *Oct 24, 1988Apr 26, 1990Schering AgWaessriges saures bad zur galvanischen abscheidung von glaenzenden und rissfreien kupferueberzuegen und verwendung dieses bades
DE19758121A1 *Dec 17, 1997Jul 1, 1999Atotech Deutschland GmbhWń▀riges Bad und Verfahren zum elektrolytischen Abscheiden von Kupferschichten
DE19758121C2 *Dec 17, 1997Apr 6, 2000Atotech Deutschland GmbhWń▀riges Bad und Verfahren zum elektrolytischen Abscheiden von Kupferschichten
EP0785297A2Mar 19, 1990Jul 23, 1997ATOTECH Deutschland GmbHAn aqueous acid bath for the electrodeposition of a shiny and tear-free copper coating and its application
EP1798314A1 *Sep 25, 2006Jun 20, 2007Rohm and Haas Electronic Materials, L.L.C.Leveler compounds
EP2161355A1 *May 21, 2007Mar 10, 2010C. Uyemura & Co., Ltd.Copper electroplating bath
WO2006094755A1Mar 1, 2006Sep 14, 2006Atotech Deutschland GmbhPolyvinylammonium compound, method of manufacturing same, acidic solution containing said compound and method of electrolytically depositing a copper deposit
Classifications
U.S. Classification205/298, 205/297, 106/1.26, 205/296
International ClassificationC25D3/38
Cooperative ClassificationC25D3/38
European ClassificationC25D3/38