DE1521031B2 - Acid copper bath for the galvanic deposition of shiny, leveled coatings - Google Patents

Description

(-CH ₇ -CH-

contains where R is the amino group or its functional derivatives or one via an N atom bonded, optionally containing further heteroatoms, heterocyclic radical and η a means an integer between about 5 and 1000.

2. Acid copper bath according to claim 1, characterized by a content of

Polyvinylamine,

Ν, Ν-dimethyl-polyvinylamine,

N- poly vinylacetamide,

N-poly vinylthioethyl urethane,

N-polyvinyl carbamate,

N-Poly viny! Thiourea,

N-poly vinyl succinimide,

N-poly vinylimidazole,

N-polyvinyl-NJvi'-ethylene urea,

N-polyvinylpyrrolidone- (2),

N- poly vinyl morphol in,

N-polyvinylmorpholinone- (3),

N-polyvinylbenzimidazole,

N-polyvinyl-5-alkyl-oxazolidone- (2) or

N-poly vinyl caprolactam

each alone or in a mixture with one another.

3. Acid copper bath according to Claims 1 and 2, containing the compounds indicated in amounts of 0.0005 to 0.1 g / liter, preferably 0.0005 to 0.03 g / liter.

4. Acidic copper bath according to Claims 1 to 3, containing brighteners known per se oxygen-containing high molecular weight compounds in amounts of 0.01 to 10 g / liter, preferably 0.02 to 5 g / liter, and organic thio compounds with preferably one or more water-solubilizing groups in the molecule in amounts of 0.002 to 0.2 g / liter, preferably 0.005 to 0.1 g / liter.

5. Acid copper bath according to claims 1 to 4, containing additional other conventional brighteners and / or wetting agents.

Certain organic substances in small amounts can be added to instead of a bath crystalline matt deposit to obtain shiny copper coatings. So was z. B. the use of organic Thio compounds such as thiourea, thiohydantoin, thiocarbamic acid esters, thiophosphoric acid esters as well as numerous derivatives of these compounds have been proposed. These substances possess but also many disadvantages that have led to

ίο that they are no longer suitable for modern bright copper baths to be used. So z. B. the ductility of the copper coating is greatly reduced, the evenness the layer thickness distribution worsens, the precipitation is in certain current density ranges black-streaked or in relief. Connections have also been made recently for the aforementioned purpose suggested that not only one or more doubly negatively charged sulfur atoms in the molecule, but also one or more sulfonic acid groups or other water-solubilizing groups own (see German patents 10 37 801, 1168208, 1196464 and 1201152). These connections However, in acidic copper baths, when used alone, either do not have any gloss effect more, or a limited gloss effect occurs only at high concentrations, at which the mechanical properties of the copper deposits, "especially the ductility, but so adversely affected "that practical use is no longer possible.

Only if these connections - z. B. Thioalkanesulfonic acids or thiophosphoric acid esters with water-soluble making groups - with certain high molecular substances together with the copper bath admittedly, one obtains, as can be shown, shiny copper deposits. As a high molecular weight Substances come for this z. B. fatty alcohol-ethylene oxide addition products, nonylphenol-ethylene oxide addition products, Polyethylene glycols and similar compounds in question. However, these combinations also meet the increased requirements does not do justice to practice, as their leveling effect is too low and polishing marks or defects in the base material after the copper plating still clearly to:

are seen, so that further mechanical processing is required. Since, however, all additional Polishing work is known to cause high costs, is increasingly the requirement in practice after strongly leveling baths, with which the polishing costs are reduced to a minimum can be.

It has now been found that the leveling effect of acidic copper baths containing as Brighteners high molecular weight organic compounds containing oxygen and organic thio compounds, can improve significantly if you give them one or more compounds of general formula

The invention relates to an acidic copper bath for the electrodeposition of shiny, leveled ones coatings and has the particular task of electrodeposition from aqueous, acidic solutions of copper salts to improve.

It has long been known that acidic, in particular

the most common copper sulfuric acid means about 5 and 1000.

- CH, - CH-

where R is the amino group or its functional derivatives or a heterocyclic radical bonded via an N atom, optionally containing further heteroatoms, and η is an integer between

The additives to be used according to the invention are polyvinylamine and its functional derivatives and N-heterocyclic polyvinyl compounds. These are known per se or can be prepared in a manner known per se. Polyvinylamine is formed e.g. B. by acidic or alkaline saponification of cyclic N-vinylimides, such as N-polyvinylphthalimide (U.S. Patent 24 84 423) or by saponification of polyethyl-N-vinyl -carbamat (German patent specification

8 65 901).

N-polyvinyl acetamide is obtained, for. B. by acylation of polyvinylamine with acid chloride or Acid anhydride by generally customary processes (US Pat. No. 25 07 181).

N - polyvinyl carbamate (- N - polyvinyl carbamic acid ester) form z. B. by polymerization of vinyl isocyanates with alcohols in the presence of azoisobutyric acid dinitrile (Belgian patent 5 40 975).

N-polyvinylpyrrolidone (German patent specification

9 22 378), N-polyvinylmorpholinone- (3) (British patent specification 8 49 038) and N-polyvinyl-5-alkyl-oxazolidone- (2) (USA.-Patent 29 46 773) can be obtained from the corresponding monomers, ζ. Β. by polymerization in solution in the presence of azoisobutyric acid dinitrile.

Naturally, these compounds are present in the copper bath as salts, e.g. B. as sulfates in the usual sulfuric acid electrolytes, but can also be added in salt form, e.g. B. as hydrochloride, Methyl iodides, ethyl bromides and others.

From the German patent specification 9 33 843 it is already known, galvanic baths of polyvinylamine or to add polyvinylpyrrolidone, in amounts between 0.02 and 1.0 g / liter. With their However, as has been shown, sole use in acidic copper baths does not have any gloss effect or effect Leveling achieved. The precipitate is only fine-grained, smooth and free of streaks, but it fulfills thus not in the least the demands that are made today of bright copper plating. It is found in this patent no reference to the surprising fact that these substances are the leveling Effect can improve by leaps and bounds if they are added to copper baths that contain oxygen contain high molecular compounds and organic thio compounds.

The quantities required for a significant improvement in the copper deposition, especially the leveling Effect required are extremely small and are at 0.0005 to 0.1 g / liter, generally at 0.0005 to 0.03 g / liter, depending on which basic gloss contains the copper bath.

A sulfuric acid copper sulfate solution of the following composition is generally used as the bath :

Copper sulfate (CuSO ₄ · 5 H ₂ O) 125 to 260 g / liter sulfuric acid (H ₂ SO ₄ ) 20 to 85 g / liter

Instead of copper sulfate, other copper salts can also be used, at least in part. The sulfuric acid can be partially or completely replaced by fluoroboric acid, phosphoric acid or other acids. That Bath can be chloride-free or - which is beneficial to improve the gloss - chlorides, z. B. contain alkali chlorides in amounts of 0.001 to 0.2 g / liter. Other additives can be used as additional additives customary gloss builders and / or wetting agents can be used.

In Table I, for example, substances are compiled which, according to the invention, are acidic copper baths with oxygen-containing, high molecular weight, organic compounds and organic thio compounds can be added to obtain high-gloss, leveled coatings.

Table I.

1 substance Preferred 2 concentration (g / liter) > 5 3 Polyvinylamine 0.005-0.02 4th Ν, Ν-dimethyl polyvinyl 0.005-0.03 5 amine 6th N-polyvinyl acetamide 0.005-0.03 20th 7th N-polyvinylthioethyl urethane 0.0005-0.005 8th N-polyvinyl carbamate 0.001-0.02 9 N-poly vinyl thiourea 0.0005-0.005 N-poly vinyl succinimide 0.005-0.02 25th 10 N-polyvinylimidazole 0.01-0.03 11th N-polyvinyl-N, N'-ethylene- 0.02-0.07: ' 12th harnjätoff 13th N- polyvinylpyrrolidone- ^) 0.001 .7-0.01 14th N-poly vinyl morpholine 0.005 ^ -0.05 N-poly vinylmorpholine- (3) 0.001-0.02 15th N-polyvinylbenzimidazole 0.001-0.005 N- poly vinyl-5-alkyl- 0.001-0.01 oxazolidone- (2) J '-. ■ ■ »· ■ 35 N-poly vinyl caprolactam 0.0005-0.002

In Tables II and III are known copper bath additives on the basis of high molecular weight organic compounds and organic compounds containing oxygen Thio compounds, which preferably contain one or more water-solubilizing groups, put together, which show an unsatisfactory leveling when used alone. The amounts that are added to the copper bath, lie within the following limits:

High molecular weight organic compounds containing oxygen 0.01 to 10 g / liter, preferably 0.02 to 5 g / liter;

organic thio compounds with water-solubilizing groups from 0.002 to 0.02 g / liter, preferably 0.005 to 0.1 g / liter.

Tabel!!

substance Preferred concentration (g / liter) 1 Polyvinyl alcohol 0.05-0.4 2 Carboxymethyl cellulose 0.05-0.1 3 Polyethylene glycol 0.05-0.5 4th Polypropylene glycol 0.01-0.2 5 Stearic acid polyglycol ester 0.5-5.0 6th oleic acid polyglycol ester 0.5-5.0 7th Stearyl alcohol polyglycol ether 0.5-5.0 8th Nonylphenol polyglycol ether 0.5-2.0

Όό 1

Tables!

substance

Preferred
concentration

(g / liter)

Dithiophosphoric acid-O.O-di-0.005-0.1

ethyl-S- [w-sulfopropyl] ester,

Sodium salt

Thiophosphoric acid O-ethyl-0.01-0.15

bis- [f) -sulfopropyl] ester,

Disodium salt

Thiophosphoric acid tris-0.02-0.15

[w-sulfopropyl] ester,

Trisodium salt

3-mercaptopropane-1-sulfone- 0.005-0.08
acidic sodium

HN-diethyl-dithiocarbamine-0.01-0.1

acid [f> -sulfopropyl] ester,

Sodium salt

6 2-mercaptobenzothiazole-0.02-0.1
S-propanesulfonic acid sodium

7 thioglycolic acid 0.001-0.003

If you use the compounds of Tables II and III together with one or more substances Table I in acidic copper baths, there is a clear and sudden improvement in the leveling effect. The mixing ratios of the individual components can vary widely Limits vary. It has proven to be favorable if a weight ratio of the in Tables I, II and III substances listed as examples of about 1:10: 2 to 1: 200: 20 are present. As further additions the bath can use other known brighteners, such as thiourea or its derivatives, dithiocarbamic acid esters, Contain thiosemicarbazones, phenazine dyes or alkaloids.

The following examples explain the invention:

At sp ie 1 1
A copper bath of the composition

200 g / liter copper sulphate (CuSO ₄ 5H ₂ O),
55 g / liter sulfuric acid conc.,
0.05 g / liter sodium chloride

are used as brighteners

2.0 g / liter stearyl alcohol polyglycol ether and 0.08 g / liter of sodium salt of dithiophosphoric acid O, O-diethyl-S- [w-sulfopropyl] ester

admitted.

At a bath temperature of 20 to 25 ° C, glossy copper deposits are obtained with an average current density of 4.0 A / dm ² and with cathode movement, but the leveling of the roughness of the base material is only 46% with a layer thickness of 24 μm. If an additional 0.005 g / liter of N-polyvinylpyrrolidone- (2) is added to the bath, the leveling increases to 75% under the same working conditions, i.e. it increases by 63%.

Example 2
The bath according to Example 1 will be

0.1 g / liter polyethylene glycol and

0.03 g / liter of 3-mercaptopropane-1-sulfonic acid sodium

admitted. The leveling effect is about 50% under the same working conditions as "'in Example 1 with a layer thickness of 24 μm copper. Adding 0.01 g / liter of N-polyvinylamine increases the leveling to 83%, which is an increase . thus 66% an equally dramatic improvement in deposition receives min; when 0.02 g / liter N-polyvinylimidazole or 0.004 g / liter of N-polyvinyl-5-alkyloxazolidons- (2) is added to the copper bath in place of the polyvinylamines.

Similar good effects can be found when each other in the table is used together I achieve the substances listed with the compounds of Tables II and III.

Claims (1)

Patent claims: 1. Acid copper bath for the galvanic deposition of shiny, leveled coatings with a Content of oxygen-containing high molecular weight organic compounds and organic thio compounds, characterized in that this bath also has one or more connections the general formula