DE1255436B - Stabilized reductive copper bath - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

PATENT LETTERING

Int. Cl .:

C23c

German class: 48 b -3/02

Number:

File number:

Registration date:

Display day:

Issue date:

Sch 37483 YI b / 48b

July 31, 1965

30th of November. 1967

June 12, 1968

The patent specification corresponds to the patent specification

Technical processes are used to apply metal layers to a wide variety of base materials increasing attention, in which the metals are reductively deposited from baths without an external power source will. In particular, the deposition of copper through reduction has been increasing in recent years Meaning found, since reductive copper precipitates for the production of conductive layers on plastic plates, z. B. in the electronics industry for the production of printed circuits, particularly suitable are.

The previously known bath compositions of reductive copper baths, however, have the Disadvantage of a very low stability, so that it is necessary to achieve the highest possible deposition rate usually have to be heavily overloaded and discarded after the metal has been worked out.

In order to increase the bath stability, additives are already used, preferably sulfur-containing compounds, became known, but these may only be added in small amounts, since larger concentrations greatly reduce the rate of deposition of the metal or even prevent the deposition be able. In some compounds it has also been found to be disadvantageous that this one Cause darkening of the copper layer. Because of the especially at higher temperatures Often the sulfur-containing compounds have a low resistance to alkali, so it is not possible to use reductive copper baths to stabilize satisfactorily for a longer period of time.

In contrast, it has now been found that selenium compounds of the general formula ',

and or

R ¹ - Se - R ²
_? —Se —R ₂ IX
R ₂

where R ^{1 is} hydrogen, a monovalent metal or an organic radical optionally containing carboxyl groups, R ^{2 is} cyanide or an organic radical corresponding to R ¹ and X is an inorganic acid radical, able to permanently stabilize reductive copper baths in a wide concentration range even when higher temperatures are used. A special technical effect of these compounds is that they enable the deposition of bright copper layers of constant thickness from such baths.

Well suited are z. B. Compounds in which the radicals R ¹ and R ^{2 are the} same and optionally in the stabilized reductive copper bath

Patented for:

Schering Aktiengesellschaft,

Berlin and Bergkamen,

1000 Berlin 65, Müllerstrasse 170/172

Named as inventor:

Dr. Wolfgang Clauss, 1000 Berlin

Carbon chain through OH groups or halogen atoms, e.g. B. chlorine atoms, mono- or polysubstituted carboxyalkyl or carboxyalkenyl, where the carboxyl group is present one or more times and is either free or in a functionally modified form, and compounds in which the radicals R ¹ and R ^{2 are} different and the or have the aforementioned meaning or hydrogen, alkyl, optionally aryl, arylalkyl, arylacyl, monosubstituted or polysubstituted by halogen atoms and / or alkyl and / or alkoxy and / or acyloxy and / or the nitro group and / or the carboxyl group and / or the sulfonic acid group Represent CN group, sodium or potassium.

Additives to be used according to the invention are, for. B. the following:

A. phenylselenic acid,,

o-, m- or p-nitrophenylselenoic acid,

o-, p-methylphenylselenoacetic acid,

o- or p-methoxyphenylselenacetic acid,

o- or p-chlorophenylselenoacetic acid,

3,4-dimethylphenylselenoacetic acid,

2,4-dimethylphenylselenoacetic acid,

Benzyl selenoacetic acid,

Ethyl selenoacetic acid,

Selenium diacetic acid,

Selenium dipropionic acid,

Selenium dibutyric acid,

Bettcylselenobutyric acid.

B. Sodium Selenocyanate,
Potassium selenocyanate,

o-, p- or m-nitrophenyl selenocyanate,
o-, p- or m-methylphenyl selenocyanate,
p-methoxyphenylselenocynate,
p-ethylphenyl selenocyanate,

809 566/217

3 4

p-Carboxyphenylselenocyanat, The application of additives to stabilize

p-acetoxyphenyl selenocyanate, reductive copper baths of usual composition

l-Cyanselenobenzenesulfonic acid- (4), can be used in concentrations of about 0.001 to 0.300 g / l

o-, p- or m-chlorophenyl selenocyanate, bath liquid take place, the compounds

2-Nitro-4-chlorophenyl selenocyanate, 5 added both alone and mixed with one another

l-methoxy- ^ nitrophenyl selenocyanate can be. The stabilized according to the invention

3-carboxy-4-carbmethoxyphenyl selenocyanate, copper baths also contain the usual ingredients

2,4,6-tribromophenyl selenocyanate, parts, d. H. Copper salts, reducing agents, buffer

Methyl selenocyanate, substances, complexing agents as well as wetting and gloss agents

Ethyl selenocyanate, medium i.a.

n-butyl selenocyanate, The following examples describe some invented

tert-butyl selenocyanate, stabilized reductive copper baths according to the invention, with

n-Hexyl selenocyanate, which, for example, articles made of plastics

n-decyl selenocyanate, or other materials can be copper-plated.

Selenium acetic acid, 15. .

oc-selenium cyanopropionic acid, example 1

α-selenium cyanobutyric acid. CuSO ₄ · 5 H ₂ O 10 g / l

Disodium ethylenediamine tetraacetic

C. Carboxymethyl-dimethyl-selenonium bromide, acid 20 g / l

Phenyl acyl dimethyl selenonium bromide. 20 NaOH 16 g / l

Paraformaldehyde 4 g / l

Benzylselenoacetic acid 2 mg / l is particularly notable of these additives

selenium cyanide fatty acids listed in group B.

through a long-lasting stabilizing effect r> e 1 s ρ 1 e l ζ,

so that reductive copper baths with a content of 35 CuSO ₄ · 5 H ₂ O 20 g / l

on one or more of these compounds practically disodium ethylenediamine tetraacetic

can be kept indefinitely. The easy water solubility acidic 25 g / l

These compounds also allow a particularly NaOH 8 g / l

good dosage. Paraformaldehyde 12 g / l

The carboxyl groups of the 30 p-nitrophenylselenoacetic acid mentioned under A and B 160 mg / l

Connections can also be modified in function.

ter form, e.g. B. in the form of salts, expedient example

in the form of sodium or potassium salts. CuSO ₄ · 5 H ₂ O 5 g / l

For the selenonium compounds, the usual disodium ethylenediamine tetraacetic

Chen acid residues of the onium compounds use 35 acid 16 g / l

find, e.g. those of the inorganic acids, useful NaOH 8 g / l

moderately of the hydrogen halide acids. Paraformaldehyde 16 g / l

The compounds mentioned can per se p-methylphenylselenacetic acid .... 40 mg / 1 known methods are produced, as z. B.

can be described in the following literature references: 40 Example 4

_GrUDüeA : CuSO ₄ -SH ₂ O .20 g / l

^F1 ^ 'disodium ethylenediamine tetraacetic

G. T. Morgan and W. M. Porri t, acid 40 g / l

J. former Soc, 127, 1757 (1925); NaOH 24 g / l

B e h a g e 1 and Rollmann, 45 paraformaldehyde;.: 16 g / l

J. pr. Chem. (2), 123, 338 (1929); Phenylselenacetic acid 70 mg / 1

E. Schulze et al., Reports from the Germans

Chemical Society, 8, 773 (1875); Example5 -

_GruüDeB . CuSO ₄ -SH ₂ O .. -10 g / l

«Jruppeß. _5o triethylenetetramine 10 g / l

Houben - W eyl, 9, 937, 939, 943, Metho- NaOH 16g / l

that of organic chemistry, edition 4 (1955); Paraformaldehyde 10 g / l

H. B a u e r, reports of the German chemical potassium selenocyanate 2 mg / 1

Society, 46, 93 (1913);

Example6

^{Group C:} CuSO ₄ -SH ₂ O 10g / 1

Houben - Weyl, 9, 1035, methods of triethylenetetramine 8 g / l

organic chemistry, edition 4 (1955). NaOH 16 g / l

Paraformaldehyde 16 g / l

Effective stabilizers according to the present 60 selenium cyanacetic acid 1 mg / 1

Invention are also those selenium compounds that

z. B. by hydrolysis of the selenocynate in the alkaline B e 1 s ρ i e 1 7

Medium can arise, ie selenols of the general CuSO ₄ · 5 H ₂ O 10 g / l

my formula disodium ethylenediamine tetraacetic

R2 - Se - H ⁶ 5 acid 20 g / l

NaOH 12 g / l

with R ² as defined above, or its paraformaldehyde 8 g / l

Metal salts. p-nitrophenyl selenocyanate 1 mg / 1

'- ..' 'Examples

CuSO ₄ -5H ₂ O ..... 10 g / l

Rochelle salt ■ .. 24 g / l

NaOH 24 g / l

Paraformaldehyde 12 g / l

■ Selenium acetic acid 3 mg / 1

B e i s ρ i e 1 9

CuSO ₄ · 5 H ₂ O 10 g / l ίο

Rexenol (trinatrium salt of the hydroxyethyl diamine ethylene

triacetic acid) 18 g / l

NaOH 12g / l

Paraformaldehyde 8 g / l

Selenium acetic acid 2 mg / 1

Example 10

CuSO ₄ · 5 H ₂ O 10 g / l

Disodium ethylenediamine tetraacetic ao

acidity 20 g / l

NaOH 16 g / l

Paraformaldehyde 8 g / l

Carboxymethyl dimethyl

selenonium bromide 200 mg / 1

Example 11

CuSO ₄ · 5 H ₂ O 10 g / l

Disodium ethylenediamine tetraacetic

acidity 20 g / l

NaOH 16 g / l

Paraformaldehyde 8 g / l

Phenylacyl-dimethylselenonium bromide 180 mg / l

Claims (3)

Patent claims: 1. Use of one or more selenium compounds of the general formula R ¹ —Se —R ² (I) and or R ₂ -Se-R ₂ ] X (II) R ₂ copper salt solutions serving as stabilizers in the reductive copper deposition, where R ^{1 is} hydrogen, a monovalent metal or an organic radical optionally containing carboxyl groups, R ^{2 is} cyanide or an organic radical corresponding to R ¹ and X is an inorganic acid radical. 2. Use of selenium compounds of the formula I ^{where R 1} = R ² , where R is an aliphatic, saturated or olefinic mono- or polybasic acid or acid derivative which is optionally mono- or polysubstituted by hydroxyl or halogen. 3. Use of selenium compounds of the formula I with different radicals R ¹ and R ² , where R, in addition to the compound groups mentioned, is a singly or multiply halogen and / or nitro-substituted and / or sulfonated organic radical. 709 690/426 11.67 © Bundesdruckerei Berlin