DE1224111B - Acid galvanic copper and nickel baths and process for depositing the coatings - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C23b

German class: 48 a -5/00

Number: 1224111

File number: D 36777 VI b / 48 a

Filing date: August 10, 1961

Opening day: September 1, 1966

So far, galvanically effective additives, such as gloss, leveling, grain refinement, pore prevention, Leveling and wetting agents, the baths in the form of aqueous solutions of a certain concentration admitted. During the operation of the baths there is a more or less high consumption this additive. The critical concentration would therefore soon be reached in the bathroom, i.e. H. the concentration below which usable precipitates are no longer obtained when they are used up Funds would not be continuously replenished. The proper operation of such baths requires therefore constant analytical monitoring to ensure that the concentration of the additives is always in the to maintain the range required to achieve perfect precipitation. In practice it is done however, the addition is often purely empirical after a certain period of time and often only when Disturbances become visible, which can lead to rejects. With the periodic addition of Additives can also lead to an overconcentration in the cathode compartment as a result of insufficient mixing arise, which has an unfavorable effect on the metal deposition, moreover, there is a very general one the risk of underdosing or overdosing the additives in the electrolyte, which can lead to malfunctions can give rise to manifold kinds.

In contrast, according to the invention, galvanically effective, sparingly soluble, organic compounds which have at least 2 carbon atoms, which are only bound to heteroatoms and whose saturation concentration is 0.5 to 500 mg per liter of bath liquid and whose critical concentration is half to one eighth of this saturation concentration , used in a multiple amount of this saturation concentration in the baths, which form a heterogeneous phase in the bath. As a result, the bath liquid is constantly and self-regulatingly kept close to the saturation concentration of the added component. If the concentration of additives in the bath decreases due to consumption, the saturation concentration is restored from the poorly soluble sediment, so that further additions to correct the bath during operation are not necessary. Since the concentration of additives in the electrolyte remains constant, the bath does not require ongoing analytical monitoring. In the baths used in accordance with the invention, there is therefore neither the risk of underdosing nor of overdosing the additives. Furthermore, the constant additive concentration of the electro-acid ensures galvanic copper and nickel baths and
Process for depositing the coatings

Applicant:

Dehydag Deutsche Hydrierwerke G. m. B. H.,

Düsseldorf, Henkelstr. 67

Named as inventor:

Dipl.-Ing. Gregor Michael, Düsseldorf

lyten a completely even consumption, which in addition to an increase in the quality of the precipitation also the economy of the process is improved. When separating the precipitates from If the electrolyte is always composed of the same composition, its quality is naturally completely constant remain what for the deposition of strong metal layers, such as these z. B. in the roll copper plating and the manufacture of record stencils are of considerable practical importance is. The sparingly soluble additives of the heterogeneous bath phase can be liquid or solid and in the latter case usually form a soil body. The fixed funds can also be in Baths are used, which are continuously or periodically pumped around. You can do it for example, switch on by means of a release filter in the circulation line.

Such carbon atoms bound only to heteroatoms can be found e.g. B. in nitrogen and / or sulfur-containing groups, such as thiourea groups, Dithiocarbamic acid groups, thioxanthogenic acid groups, trithiocarbonic acid groups, xanthogenic acid groups, Thioimidazole or thiobenzimidazole groups, mercaptothiazole or mercaptobenzthiazole groups. These compounds can also contain water-solubilizing radicals, such as carboxyl groups and sulfonic acid groups, which are associated with the Heavy metal ions in the baths form sparingly soluble metal salts. Furthermore, the additives can also more than groups identified by the carbon atom bound only to heteroatoms contain twice and in combination with one another, such as, for example, sparingly soluble compounds, the simultaneously one or more thiourea groups and one or more dithiocarbamic acid groups own.

One can therefore often start from known gloss, leveling and similar substances,

609 658/348

3 4

which have at least 2 carbon atoms which become. You can use the usual wetting agents in the baths, are only bound to heteroatoms and are bound by the well-known Äthylenoxydanlagungsprodukte Introduction of suitable substituents, for example higher molecular weight organic compounds with aus-aryl radicals, are made difficult to dissolve. You can use exchangeable hydrogen atoms, alkyl sulfate and others, but also start from insoluble products 5 add. These wetting agents are soluble but work and this, for example, by increasing the acidity in a wide range of concentrations and concentrations the bath electrolyte or in others must therefore not be strictly monitored. Befall by adding organic solvents, how does the poorly soluble soil body consist of a Solubilize ethanol, isopropanol and the like. Gloss agent whose leveling effect is insufficient

It is advantageous if the saturation concentration is io, so that one can improve the leveling

of the poorly soluble agents usually at least leveling agents either also in the form of a

twice the critical concentration of the poorly soluble soil body or else in

Means is. The saturation concentration of the dissolved form can also be used. In the latter

additive used according to the invention is in tem case the content of the bath requires leveling

the electrolyte used in each case at around 0.5 15 medium, naturally according to the monitoring. The middle

up to 500 mg / l, in particular 2 to 300 mg / l. Through must from time to time according to his

the upper limit of the saturation concentration need to be added. Are particularly advantageous

the maximum content of the electrolyte of accordingly sparingly soluble additives, the several

Additives are determined and an overdose has functions that are simultaneously high-

certainly avoided. Giving and leveling the critical concentrations and also providing a practical

trations are usually half to see one needs adequate temperature tolerance

Eighth of the saturation concentration, so own that. But there are also quite a number of

Baths that only have a saturation concentration technical galvanizing processes in which

of 50 or 12.5% of additives, no high gloss is required and already one

still deliver perfect metal deposits. With 25 grain refinement the technical requirements

corresponds to a normal bath load of about 0.5 Amp./l.

the hourly consumption of additives about In those cases in which the bath additive is only 3 to 16% of the difference between the saturation and the sparingly soluble additional concentration according to the invention and critical concentration (Konmitteln and possibly wetting agents exist, can centering tolerance range), with which a certain amount of time the baths are operated completely maintenance-free, Working reserve against unforeseen incidents, provided that care is taken to ensure that the pumping over is created and local underdosing of filtration works perfectly and the additives closed is. in the release filter must be renewed in good time. In order to

As an advantageous embodiment of the invention is not only a much simpler, but

According to the procedure, it has been found that it is more difficult to operate the baths more efficiently. By

To accommodate soluble agents in a dissolving filter, the self-regulation of the baths will affect the attack

which practically eliminated in the continuous bath filtration in the exclusion pieces.

Circulation line is installed. To avoid a blockage The following examples illustrate the

of the dissolving filter due to contamination of the bath,

avoid, a dirt trap filter is connected upstream. 40 B e i s' e I 1

The sparingly soluble additive can be mixed with kieselguhr, P

Activated carbon, special chamotte and other porous For the acidic galvanic copper plating is a

Mixed masses or, in the case of liquid agents, a bath of the following composition:

to be soaked with it. As a result, the _through-01Λ ,, " _f w" _tn cn r _U n

Permeability and incompressibility of the filter layer 45?} ° g copper sulfate CuSO ₄ · 5 H ₂ O,

guaranteed. The wettability of the solid ^{hard- liy} i ^g } ^ cnwere acid,

soluble agent by the bath liquid can by ⁸ ^ * ^e _t ? Addition product of 8 moles can be improved with the addition of wetting agents. For ethylene oxide on 1 mole of a coconut oil - preservation of the saturation concentration in the galvanic alcohol mixture C ₁₂ to C ₁₈ .
50 The bath is circulated and continuously filtered to achieve the usual bath circulation speed to achieve this. The usual dirt trap filter is followed by a sufficient continuous filtration with a dissolving filter, which is a poorly soluble one to two bath volumes per hour. Gloss agent N, N "-di-benzylthiocarbaminyl-diethylen-

The process according to the invention can be carried out in acidic triamine-N'-dithiocarbonyl-S-propane-cu-sulfonic acid

Electroplating copper and nickel baths applied 55 copper of the formula

CH ₂ - NH - C - NH - CH ₅ . - H ₂ CS

NC- S (CH ₂ ) ₃ - SO ₃ 1/2 Cu
CH ₂ - NH - C - NH - CH ₂ - H ₂ C

contains. The bath delivers with a circulation of one and pore-free copper precipitates in the current density bath volume per hour shiny, smooth, bud area of 0.5 to 8 Amp./dm ² at a temperature

Tolerance from 17 to 30 ^° C. The leveling capacity of the bath is sufficient for many practical purposes, so that the use of other additives is unnecessary. The saturation concentration of the brightener is 10 mg / 1, the critical concentration is around 50% of the saturation concentration, i.e. around 5 mg / 1. The consumption of gloss substance per ampere hour is 0.8 mg, which ensures that the bath works properly even if the release filter fails up to 6 ampere hours per liter.

Example 2

Is in an acidic galvanic copper plating bath of the composition according to the example 1 in the dissolving filter as a sparingly soluble brightener piperazine - N, N '- bis - dithiocarbonyl - S - propane-ω-sulfonic acid Sodium from the formula

S CH ₂ - H ₂ CS

NaO ₃ S - (CHa) ₃ - S - C - NN - C - S - (CH ₂ ) ₃ - SO ₃ Na

CH ₂ - H ₂ C

used, this bath delivers shiny, smooth, bud and pore-free copper coatings in the current density range from 0.5 to 8 Amp./dm ² with a temperature tolerance of 17 to 30 ⁰ C. The leveling effect of the Bades is sufficient for many areas of application without the addition of special leveling agents. The saturation concentration of the soil body is 40 ml / 1, the critical concentration is around 25% of the saturation concentration, i.e. around 10 mg / 1. With a rinse aid consumption of 1.2 mg per ampere hour, a working reserve of 25 ampere hours per liter is guaranteed in the bath.

Example 3

In an acid electroplating copper bath of the composition

210 g / l copper sulphate CuSO ₄ 5 H ₂ O,
60 g / l sulfuric acid,

8 g / l of the adduct of 8 moles of ethylene oxide with 1 mole of a coconut fatty alcohol mixture Ci ₂ to C18

is used as a sparingly soluble brightener in a dissolving filter connected downstream of the usual dirt trap filter piperazine-N ^ '- bis-dithiocarbonyl-S-propionic acid Sodium the formula

NaOOC - (CH ₂ ) ₂ - S - C - N

CH ₂ - H ₂ C

CH ₂ - H ₂ CN - C - S - (CH ₂ ) ₂ - COONa

used. The bath provides for a circulation of a bath volume per hour shiny, smooth, bud and pore-free copper coatings in the current density range of 0.5 to 8 Amp./dm ² at a temperature tolerance 17-30 ⁰ C. At the saturation concentration of the base body 30 mg / 1, a critical concentration of about 12 mg / 1, which is 40% of the saturation concentration, and a brightener consumption of 1.5 mg per ampere hour results in a working reserve of the bath of 12 ampere hours per liter.

Example 4

In one of the usual dirt trapping filters of the acidic galvanic copper bath of the same basic composition as in Example 3 downstream dissolving filter is a mixture of the solid as a solid In Example 1, the sparingly soluble glossy floor body used and that acting as a leveler sparingly soluble l-benzylthiocarbaminyl-2-mercaptoimidazoline the formula

CH ₂ -CH ₂ -

■ N

C = S
C = S

CH ₂ - HN '

60

65

used. The bath provides uniform gloss, good planarizing copper precipitation in the current density range of 0.5 to 8 Amp./dm ² at a temperature tolerance 17-30 ⁰ C. for a circulation of a bath volume per hour, the saturation concentration of the Einebnerbodenkörpers is 6 mg / 1, the critical concentration is around 1.5 mg / l, which corresponds to around 25% of the saturation concentration. From these values and the consumption of about 0.4 mg / 1 per ampere hour, the bath has a working reserve of 11 ampere hours per liter.

Example 5

In an acidic electroplating copper bath of the same composition as in Example 3 as a sparingly soluble leveling agent, the condensation product of 1 mole of phenylthiourea and 1 mol of formaldehyde in addition to 40 mg / 1 of a soluble brightener, namely Ν, Ν-diethyldithiocarbaminyl-S-propane-cu-sulfonic acid Sodium, used. In this bath only the leveling agent is self-regulating, whereas the dissolved brightener requires constant monitoring. The advantage Compared to the usual procedures, the ongoing monitoring on the in a wide Concentration range acting gloss agent is limited, while difficult to control small amounts of the leveler is not required. At a

Circulation of one bath volume per hour, the bath results in well-leveling, shiny and pore-free copper coatings in the current density range from 1 to 8 Amp./dm ² with a temperature tolerance of 17 to 30 ⁰ C. With a saturation concentration of the leveling agent of about 4 mg / 1, one critical concentration of about 0.5 mg / 1 (corresponding to 12.5% of the saturation concentration) and a consumption of about 0.2 mg per ampere hour

CH ₂ - H ₂ C results in a working reserve of the bath of about ampere hours per liter.

Example 6

N-phenylthiocarbaminylpiperazine - N '- dithiocarbonyl - S - propane - ω - sulphonic acid copper is added as the sparingly soluble brightener in an acid electroplated copper bath of the composition according to Example 1

- C - NN - C - S - · (CHa) ₃ - SO ₃ V2 Cu

S CH ₂ - H ₂ CS

given. With a circulation of one bath volume per hour, the bath delivers shiny, smooth, well-leveling, bud- and pore-free copper coatings in the current density range from 1 to 8 amps / dm ² with a temperature tolerance of 17 to 30 ° C. The saturation concentration of the copper salt is around 8 mg / 1, the critical concentration is around 38% of the saturation concentration and is around 3 mg / 1. With a rinse aid consumption of 0.6 mg per ampere hour, a working reserve of 8 ampere hours per liter is guaranteed in the bath.

Example 7

In an acidic nickel electroplating bath of the composition

270 g / l nickel sulfate NiSO ₄ ■ 7 H ₂ O,
60 g / l nickel chloride NiCl ₂ 6 H ₂ O,
30 g / l boric acid,

1 g / l decyl sulfate as a wetting agent,
2.5 g / l N- (benzenesulfonyl) -benzoic acid amide of the formula C ₆ H ₅ -CO-NH-SO ₂ -C ₆ H ₅ as a soluble basic gloss

L-benzylthiocarbaminyl-2-mercapto-irnidazoline is used as a sparingly soluble leveling body

CH ₂ - HN

CH ₂

-N

* ^> - CH ₂ - HN ^/

C = S
C = S

used. In this bath, only the leveling agent has a self-regulating effect, whereas the dissolved basic gloss agent requires constant monitoring, but this is of no serious importance in view of its wide range of action. In a circulation of a bath volume per hour, the bath provides pore-free, ductile nickel deposits with uniform gloss and Einebnungsvermögen in the current density range 1-8 Amp./dm ² at a temperature tolerance of 45 to 60 ⁰ C. The saturation concentration of the sparingly soluble leveling agent is 55 ⁰ C is around mg / 1, the critical concentration at the same temperature is around 3 mg / 1, with a sufficiently large range between the saturation and critical concentration to ensure that the bath works satisfactorily.

Claims (3)

Patent claims: 1. Acid electroplating copper and nickel baths of the usual composition with a content of galvanically active organic additives, characterized in that they contain poorly soluble organic compounds have at least 2 carbon atoms which are bonded only to heteroatoms and their Saturation concentration 0.5 to 500 mg per liter of bath liquid and its critical concentration one-half to one-eighth of this saturation concentration, in a multiple amount this saturation concentration included, so that the majority of the additive in undissolved Remains shape in the bathroom. 2. Baths according to claim 1, characterized in that they are organic as additives Contain compounds which, in addition to thiourea residues, also contain dithiocarbamic acid residues in the molecule own. 3. Method of electrodeposition of copper and nickel coatings using the baths according to claim 1 and 2, characterized in that. the unresolved portion the sparingly soluble, galvanically active organic additives in one of the usual Dirt trap filter housed downstream release filter and by periodic pumping the bath ensures that a sufficient concentration of additives is maintained. Considered publications:
German Patent No. 1,037,801;
German Auslegeschriften No. 1,071,438,1008,542; Austrian patent specification No. 172 066 (reported in Chemisches Zentralblatt, 1953, p. 3473);
French patents No. 1097123,1181721: USA.-Pat. No. 2,799,634.