DE202015003382U1 - Electrolytic deposition of copper from water-based electrolytes - Google Patents

Abstract

An additive mixture for an aqueous dye-free copper electrolyte having a pH in the range of 1 to 2 and a copper concentration of 0.3 to 1.2 mol Cu / L for the deposition of high-gloss, high-gloss copper coatings, wherein the additive mixture comprises all organic additives of the electrolyte.

Description

The innovation relates to an additive mixture containing all organic constituents for the electrolytic dye-free deposition of copper from a water-based electrolyte. The electrolyte can be used both for the galvanization of plastics of all kinds, as well as for the reinforcement of printed circuit tracks, as well as for the deposition of decorative coatings on plastics, sanitary components, automotive parts and others.

Another purpose is the "Sudkupferabscheidung" before the subsequent actual coating with copper.

It is known that among other sulfuric acid copper electrolytes organic additives are added in order to obtain functional and decorative properties of the copper coatings.

These organic adjuncts are then generally, depending on the area of action in brighteners (Brightner), if a major gloss-forming function is present, Leveler, if a main, leveling function and carrier and wetting agent, if a main Function as basic glossifier present exists. These organic constituents are usually introduced separately into the electrolyte with individual metering pumps.

Furthermore, the organic additives are usually classified under the name Glanzzusatz as well as glossy, which increase the gloss distribution and the deposition in the low current density range.

The use of molasses, coffee extract, basic dyes, thiophosphoric acid ester and / or thiourea has long been known. However, the use of the above-mentioned substances is now almost no longer use, since the quality of the coatings can be significantly improved by many other substances.

In US 2,799,634 A describes the use of dextrose with 2-thiodantoin; the advantage of combining dextrose with 2-thiodantoin is said to be stability in the electrolyte. In detail, it should be achieved here that the gloss-forming effect is retained even after electroless times of several hours in the electrolyte.

Dyes and the use of 2-valent sulfur compounds, however, are in US 7,887,693 B2 and US 2008/0314757 A described. Here, inter alia, by the use of the dye tetrakis (pyridinomethyl) Cu (II) phthalocyanine chloride as leveler in combination with 2-valent sulfur compounds such as bis (dimethylthiocarbamyl) sulfonium 1-propanesulfonate or 2-dimethylsulfonium-1-propanesulfonate as scraps, shiny and leveling copper layers are deposited.

The use of isothiourea derivatives is in US 3,179,578 A . DE 11 42 741 B , and US 3,023,152 A described. Examples of particularly gloss-forming additives with planarizing properties are N, N-pentamethylene-dithiocarbamic acid-n-propyl ester-w-sodium sulfonate or N, N-dimethyl-dithiocarbamic acid-n-propyl ester-w-sodium sulfonate.

These compounds contain one or more carbon atoms attached to heteroatoms having a short aliphatic residue of a sulfonic acid or other water-soluble group.

It is also known US 4,110,176 C the use of reaction products of polyalkanolamines with an alkylating agent, for example benzyl chloride and of polyalkyleneimines and epichlorohydrin with an alkylating agent.

In US 2,837,472 A . DE 923407 C . DE 120 71 77 B . US 2,849,351 A and US 2,907,786 A. describes the use of 2-aminothiazoles and the use of the reaction products of 2-aminothiazoles with sultones or, for example, 2-oxythiazoles with sultones. Here is spoken in particular of a gloss-forming and leveling function of the substances.

The use of at least one reaction product formed from at least one compound selected from the group consisting of dihalohydrins and 1-halo-2,3-propanediols, with at least one polyamidoamine is used in DE19758121A1 . EP 1 0425 38 A2 . EP 1 042 538 B1 . US Pat. No. 6,425,996 . WO 1999/031300 A2 . WO 1999/031300 A3 described.

In EP 0 554 275 B1 For example, polymeric phenazonium compounds in combination with 3-naphthol alkoxylates are described as high resolution compounds with gloss-forming properties. Furthermore, the special advantage here is that, in the case of high leveling, it does not result in fine pore formation, which becomes particularly visible on large-area parts.

DE 41 26 502 C1 relates to an aqueous acidic bath for the electrodeposition of bright, ductile and level copper coatings which is suitable both for the decorative area and for the reinforcement of the printed circuit traces. It is characterized by a content of polyalkylene glycol ether. These additives, in conjunction with thio compounds which contain water-soluble groups, give an outstandingly stable electrolyte. In addition, polymers and / or nitrogen-containing thio compounds can also be successfully combined, depending on the desired properties.

• a) mindestens eine Kupferionenquelle,
• b) mindestens eine die elektrische Leitfähigkeit des Abscheidebades erhöhende Verbindung sowie
• c) mindestens einen Zusatzstoff, wobei als Zusatzstoff mindestens ein Umsetzungsprodukt, gebildet aus Epihalogenhydrinen, Dihalogenhydrinen bzw. 1-Halogen-2,3-propandiolen und Polyamidoaminen enthalten ist. Die Polyamidoamine werden durch Kondensationsreaktion von Dicarbonsäuren mit Polyalkylenpolyaminen gebildet. Bei Abscheidung von Kupferschichten aus diesem Bad können Kupferschichten mit gleichmäßiger Schichtdicke abgeschieden werden.

DE 197 58 121 A1 describes an aqueous bath and a method for electrolytically shutting down copper layers. For the uniform electrolytic deposition of copper layers, in particular on printed circuit boards, an aqueous deposition bath is used, which contains the following constituents:

• a) at least one copper ion source,
• b) at least one of the electrical conductivity of the deposition bath increasing compound and
• c) at least one additive, wherein as an additive at least one reaction product formed from epihalohydrins, dihalohydrins or 1-halo-2,3-propanediols and polyamidoamines is included. The polyamidoamines are formed by condensation reaction of dicarboxylic acids with polyalkylenepolyamines. When copper layers are deposited from this bath, copper layers with a uniform layer thickness can be deposited.

WO 2007/112971 A2 relates to an electrolytic process for filling holes and recesses with metals. Disclosed is a galvanic process for filling wells, through holes, blind holes or microslak holes of a workpiece with metals, comprising contacting the workpiece containing depressions, through holes, blind holes or microsack holes with a metal deposition electrolyte and applying a voltage between the workpiece and at least one anode, so that the workpiece a current flow is supplied, which is characterized in that the electrolyte contains a redox system.

DE 199 56 666 A1 describes a method for continuously operating electrolytes. The disclosure is based on the technical problem of producing a method for the continuous operation of electrolytes, which ensures high electrolyte quality with little economic outlay, without having to accept production interruptions for regeneration. In particular, it is provided that the process for depositing glare-free metal coatings due to be able to work in three shifts on five days of the week, without causing production stoppages due to coagulation or degradation of the fine dispersed phases and no additional operating costs for a heating-cooling circuit. To solve the above problem, the publication teaches that during the continuous operation of an electrolyte diverted from these a partial flow, filtered, optionally regenerated with the addition of active substances and recycled to the operating cycle.

In the aforementioned prior art, the organic constituents are added to the electrolyte individually via separate metering pumps.

The object of the innovation, in contrast, is to provide a system combining planarizing substances, brighteners and gloss carriers and wetting agents, which neither has any pore formation nor contains dyes and is supplied as one-component additive to the electrolyte during the particularly continuous operation.

The use of dyes is sometimes considered to be disadvantageous, since practical experience has shown that pore formation often occurs as well, unless the dye-containing solutions are filtered directly into the electrolyte prior to addition. Another disadvantage of the currently known systems is in the application.

Most systems are or can be subdivided into brighteners, levelers and glossy carriers as well as wetting agents.

Disadvantage is that it comes in overdoses of individual components of various supplementary solutions, in particular the brightener and leveler to optical interference of the deposited copper layer. (Decrease in leveling, over-leveling, excessive pore formation, milky deposition, decrease in depth dispersion, etc.) Another disadvantage is the increased edge build-up to which systems known in the market tend.

The requirements, especially by the automotive industry, on strongly profiled parts with recesses or lettering, or symbols are increasing steadily. Especially with these components, it often comes to the so-called "edge formation" what previously led to high scrap rates.

The so-called "edge formation" refers to the increased deposition at the edge of the recess, etc. of a component. This is amplified when the air flow of the air injection, with which the copper systems are operated, flows directly past this.

The systems used on the market, so far only components that meet these requirements can successfully coat by the leveling of the electrolytes is configured to a low level.

In this way, however, in turn, no parts which requirements for leveling, etc., can be coated. These approaches are therefore practically impossible or only unsatisfactory feasible.

The object stated here is achieved in a first embodiment by an additive mixture (replenisher, replenisher) for an aqueous, colorless copper electrolyte having a pH in the range of <1 to 2 and a copper concentration of 0.3 to 1.2 mol Cu / L for the deposition of high-gloss, high-gloss copper coatings, wherein the additive mixture comprises all organic additives of the electrolyte.

Particularly preferably, the additive mixture comprises at least one brightener, at least one leveler and at least one wetting agent.

Also preferred is a corresponding aqueous dye-free copper electrolyte having a pH in the range of <1 to 2 and a copper concentration of 0.3 to 1.2 mol Cu / L for the deposition of high-gloss, hocheinebnender copper coatings containing at least one brightener in an amount of 0.00001 g / L to 6 g / L, in particular 0.001 to 0.08 g / L, at least one leveler in an amount of 0.00001 g / L to 4 g / L, in particular 0.0001 g // L to 0.004 g / L and at least one wetting agent in an amount of 0.00001 g / L to 10 g / L, in particular 0.004 to 0.02 g / L.

Accordingly, the additive mixture preferably contains at least one brightener in an amount of 0.00001 g / L to 6 g / L, in particular 0.001 to 0.08 g / L, at least one leveler in an amount of 0.00001 g / L to 4 g / L, in particular 0.0001 g // L to 0.004 g / L and at least one wetting agent in an amount of 0.00001 g / L to 10 g / L, in particular 0.004 to 0.02 g / L. It turned out that the substances used according to the invention in this combination have almost no tendency to form pores, almost no tendency for milky deposition and almost no decrease in the depth dispersion.

Furthermore, the components developed here and their composition practically do not tend to form edges, with a comparable level of leveling, so that here also a significant improvement could be achieved.

In a further embodiment, the novel additive mixture and thus also the copper electrolyte is characterized in that the brightener comprises a quaternized amine, a divalent sulfur compound, a reaction product of an amine with propylene oxide, ethylene oxide and epichlorohydrin and / or an alkali metal dialkylsulfosuccinate, especially sodium dioctylsulfosuccinate.

For the purposes of the present invention, the quaternized amine is particularly preferably selected from the group comprising quaternized tetraethylenepentamine, quaternized dieethylenetriamine, quaternized ethylenediamine, quaternized ethylenediamine, quaternized diethylamine, or quaternized dimethylamine, including mixtures thereof. These additives act as brighteners over the entire current density range.

Cumulatively or alternatively with respect to the choice of substance or alternatively with regard to the amount, the brightener may also contain divalent sulfur compounds, especially bis- (3-sodium sulfopropyl) disulfide, preferably in an amount of from 0.00002 g / L to 2 g / L. These additives act as scum images, especially in the low current density range.

For the purposes of the present invention, particular preference is given to the leveler comprising a reaction product of quaternized amine and benzaldehyde. This leveler is particularly effective in the high current density range and leads to high and evenly distributed leveling.

Particularly preferred according to the present invention, the wetting agent comprises a polyalkylene glycol, in particular an EO and / or PO modified or unmodified polyethylene glycol, and / or polypropylene glycol having a molecular weight of 600 to 20,000 g / mol and / or unmodified polyethylene glycol and / or polypropylene glycol with a Molar mass of 6 to 30,000 g / mol comprises. These wetting agents particularly effect a pore-free, high-gloss and cloud-free deposition over the entire current density range.

Another embodiment of the present invention involves the use of a copper electrolyte additive mixture as defined above to deposit copper on metallic or non-metallic surfaces.

Particularly preferred in terms of innovation, the electrolyte according to the innovation can be used for the galvanization of plastics of all kinds, for the reinforcement of printed conductors on printed circuits and for the deposition of decorative coatings on plastics, metals, non-ferrous metals, sanitary components or automotive parts.

EXAMPLES

The basic composition of the electrolyte according to the invention: copper sulfate: 10-300 g / l (preferably: 30-80 g / l) Sulfuric acid: 10-300 g / l (preferably: 50-100 g / l) Chloride: 10-230 mg / L (preferably: 30-100 mg / L)

Other copper salts could be used, as well as other acids such as fluoroboric acids or methanesulfonic acids. The addition of chloride, for example by hydrochloric acid, could be completely eliminated, if already halogen ions are present.

Furthermore, common brighteners, wetting agents or glossy supports as well as leveling agents could also be added to the electrolyte. The working conditions of the electrolyte: Temperature.: 10-45 ° C Cathodic current density: 0.1-14 A / dm ² PH value: Preferably <1 Electrolyte movement: Optional air injection or goods movement anodes: Preferably phosphorized Copper anodes or insoluble anodes Example 1: copper sulfate: 220 g / l Sulfuric acid 96%: 70 g / l Chloride: 60 mg / l Luster mixture 1: 2 ml / l Leveler mixture 1: 2 ml / l Wetting agent mixture: 2 ml / l

A ground Hull cell sheet having a cathodic current density of 2 A for 10 min, 3 A for 5 min and 0.5 A for 10 min at a temperature of 25 ° C was air-blown.

The coated sheets were extremely heavily flattened over almost the entire current density range, especially at 2 A and 3 A. Furthermore, the sheets were coated to a high gloss over the entire current density range.

The leveling was also uniform and almost independent of movement or ventilation.

Normally, the Hull-cell panels coated in this way have a high leveling in the air injection area when using the conventional systems, but in some cases significantly less leveling in the area in which there is less airflow.

Composition of the mixtures as above: Luster mixture 1: Bis- (3-sodium sulfopropyl) disulfide 19 g / l Reaction product of an amine with propylene oxide and or Ethylene oxide and epichlorohydrin and sodium docusate 290 g / l Leveler mixture 1: quaternized ethylenediamine 18 g / l Wetting agent mixture 1: Polyethylene glycol 4000 78 g / l Polyethylene glycol 8000 78 g / l Polyethylene glycol 12000 with free propylene oxide 20 g / l

The luster mixture 1, the leveler mixture 1 and the wetting agent mixture 1 were added together to the starting electrolyte via a single metering pump. Example 2: copper sulfate: 170 g / l Sulfuric acid 96%: 100 g / l Chloride: 120 mg / l Luster mixture 1: 4 ml / l Leveler mixture 2: 4 ml / l Wetting agent mixture 1: 8 ml / l

A ground Hull cell sheet having a cathodic current density of 2 A for 10 min, 3 A for 5 min and 0.5 A for 10 min at a temperature of 35 ° C was air-blown.

The coated panels were flattened, especially at 2 A and 3 A, over approximately 3/4 of the length of the panel. Furthermore, the sheets were coated high gloss over about 3/4 of the length of the sheet.

The leveling was also uniform and almost independent of movement or ventilation. Usually, the thus-coated Hull cells have sheets with the use of conventional systems strong fatigue and a strong flattening.

Composition of the mixtures as indicated above: Luster mixture 1: Bis- (3-sodium sulfopropyl) disulfide 19 g / l Reaction product of an amine with propylene oxide and or Ethylene oxide and epichlorohydrin and sodium docusate 290 g / l Leveler mixture 2: quaternized diethylamine 20 g / l Wetting agent mixture 1: Polyethylene glycol 4000 78 g / l Polyethylene glycol 8000 78 g / l Polyethylene glycol 12000 with free propylene oxide 20 g / l

The luster mixture 1, the leveler mixture 2 and the wetting agent mixture 1 were added together to the starting electrolyte via a single metering pump.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2799634 A [0007]
• US 7887693 B2 [0008]
• US 2008/0314757 A [0008]
• US 3179578 A [0009]
• DE 1142741 B [0009]
• US 3,023,152 A [0009]
• US 4110176 C [0011]
• US 2837472 A [0012]
• DE 923407 C [0012]
• DE 1207177 B [0012]
• US Pat. No. 2,849,351 A [0012]
• US 2907786A [0012]
• DE 19758121 A1 [0013, 0016]
• EP 1042538 A2 [0013]
• EP 1042538 B1 [0013]
• US 6425996 A [0013]
• WO 1999/031300 A2 [0013]
• WO 1999/031300 A3 [0013]
• EP 0554275 B1 [0014]
• DE 4126502 C1 [0015]
• WO 2007/112971 A2 [0017]
• DE 19956666 A1 [0018]

Claims (10)

An additive mixture for an aqueous dye-free copper electrolyte having a pH in the range of 1 to 2 and a copper concentration of 0.3 to 1.2 mol Cu / L for the deposition of high-gloss, high-gloss copper coatings, wherein the additive mixture comprises all organic additives of the electrolyte. Additive mixture according to claim 1, characterized in that it comprises at least one brightener, at least one leveler and at least one wetting agent. Additive mixture according to claim 1 or 2, characterized in that it comprises at least one brightener in an amount of 0.00001 g / L to 6 g / L, in particular 0.001 to 0.08 g / L, at least one leveler in an amount of 0.00001 g / L to 4 g / L, in particular 0.0001 g / L to 0.004 g / L and at least one wetting agent in an amount of 0.00001 g / L to 10 g / L, in particular 0.004 to 0.02 g / L , Additive mixture according to claim 2, characterized in that the brightener comprises a quaternized amine, a divalent sulfur compound, a reaction product of an amine with propylene oxide, ethylene oxide and epichlorohydrin and / or an alkali metal dialkylsulfosuccinate, in particular sodium dioctylsulfosuccinate. An additive mixture according to claim 4, characterized in that the quaternized amine is selected from the group comprising quaternized tetraethylenepentamine, quaternized dieethylenetriamine, quaternized ethylenediamine, quaternized ethylenediamine, quaternized diethylamine, or quaternized dimethylamine, including mixtures thereof. Additive mixture according to claim 4, characterized in that the dihydric sulfur compound bis (3-sodium sulfopropyl) disulfide, in particular in an amount of 0.00002 g / L to 2 g / L comprises. Additive mixture according to one of claims 2 to 6, characterized in that the leveler comprises a reaction product of quaternized amine and benzaldehyde. Additive mixture according to one of claims 2 to 7, characterized in that the wetting agent is a polyalkylene glycol, in particular an EO and / or PO modified or unmodified polyethylene glycol, and / or polypropylene glycol having a molecular weight of 600 to 20,000 g / mol and / or unmodified polyethylene glycol and or polypropylene glycol having a molecular weight of 6 to 30,000 g / mol. Use of an additive mixture according to any one of claims 1 to 8 in a copper electrolyte for the deposition of copper on metallic or non-metallic surfaces. Use according to claim 9 for the galvanization of plastics of all kinds, for the reinforcement of printed conductors on printed circuits and for the deposition of decorative coatings on plastics, metals, non-ferrous metals, sanitary components or automotive parts.