JPS6020475B2 - High-speed electroplating bath and plating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a new and improved electroplating bath that uses an insoluble anode and operates at relatively high speeds to produce nickel plating with relatively low residual stress. Regarding the plating method.

The use of soluble anodes is well known in the art for electrolytic nickel systems.

The use of soluble anodes was prescribed because the prevailing idea was that the organic additives in the electrolytic solution would be decomposed in the presence of insoluble anodes. It is also well known that the stress in the nickel plating layer is adversely affected by the non-slip anode. Therefore, for various commercial reasons, it would be highly desirable to be able to use an insoluble anode in this nickel electroplating process without decomposition of the additives or the formation of a stressed nickel plating layer. Dew. Representative U.S. patents related to Nikkemetsuki include, for example, U.S. Patent No. 2228991 (Freed), Arashi No. 240911y (Freed), and U.S. Patent No. 240911y (Freed).
No. 912 (Freed et al.), No. 2485149 (
Freed et al.), and 299836 Pijuku Castellano).

As far as can be ascertained, all of these patents also require the use of Z-conventional or modified consumable anodes. See, e.g., U.S. Pat. No. 2,228,991, page 2, column 2, lines 53-64.

Insoluble anodes that can be used in the method of the present invention include, for example, platinum-titanium alloys, platinum-tantalum alloys, Z-gold plastic-columbium (niobium) alloys, and anodes made of platinum metal itself. Alternatively, titanium anodes with mixed oxide coatings such as ruthenium dioxide titanium monodioxide coatings can also be used. "The electroplating solution of the present invention contains defined additives that do not decompose even during operations carried out in the presence of an insoluble anode, and further includes common nickel sources such as nickel sulfate and shelf acids. In addition to the detergent, it also contains orthoformylbenzene sulfonic acid as a brightening agent and a perfluoroalkyl sulfonic acid potassium formulation, commercially available under the trade name FC Moth, as a wetting agent. The case is prescribed as follows:
Minutes Concentration (Evening/So) Nickel Salt 30
~105 (as nickel) electrolyte
20-100 ortho-formylbenzenesulfonic acid 0.25-3.0FC-98
Preferred sources of 0.02 to 0.2 nickel metal include nickel sulfate, nickel citrate, nickel carbonate, etc., and these salts are used in amounts of about 135 to 470 m/s to provide the required nickel metal concentration. It is preferable.

Electrolytes that are very useful for the purposes of this invention are acidic acids, citric acid, etc., and the preferred amounts used in preparing the electroplating grades of this invention are within the range of about 22.5 to 45 Ta.

Among these, the use of palladium acid is particularly preferred. The organic components of the electroplating bath of this invention are generally brighteners and wetting agents.

The specific brightener used in formulating and preparing the specific electroplating grades of the present invention is orthoformylbenzene sulfonic acid. Also, the required wetting agent is Minnesota Mining and Manufacturing. It is a product commercially available from Kompany under the trade name FC Satoshi. For most purposes, the pH of the electroplating bath is adjusted within the range of about 2-5 and preferably 2.5-4.5. Compounds used to control this blemish also include nickel carbonate, sulfuric acid to potassium citrate or citric acid.
07. pine'd force (100 capes/sq. ft.) or less, preferably about 10.8-M. It is operated in a relatively high current density range of 8 A'd (100-600 A square feet).

The ability to use such high current densities is also another important advantage of the electroplating process according to the present invention. When using the finishing bath of the present invention, ``Nickel deposited on various plating bases is characterized by being semi-bright, ductile, and low stress.

In order to obtain nickel plating with such properties, conventional nickel electroplating methods required a consumable or soluble anode. . The invention will be better understood by reference to the following embodiments.

EXAMPLE An electroplating grade was formulated and prepared using the following ingredients:
Minutes Concentration (evening/so) Nickel sulfate 75 (as nickel) shelf
Acid 40 ortho-formylbenzenesulfonic acid 1.5FC difficulty*
0.1* Potassium perfluoroalkyl sulfonate formulation.

Before use, add enough nickel carbonate to the case to adjust its pH to about 2.
．． Adjusted to 5.

This case was used in ordinary electroplating with a platinum-titanium alloy anode, at a temperature of 55 qo and a current density of 53.8 A'.
Copper was plated at d〆(500A/square foot). The resulting nickel plated layer was semi-bright and ductile. Further analysis results showed that the stress was low. Furthermore, when using this electroplating bath, virtually no decomposition of the organic additives present in the bath was observed. Comparative Example The same procedure as in Example was repeated except that saccharin, a typical nickel brightening agent, was used in place of orthoformylbenzenesulfonic acid, and the results were compared with Example.

The nickel plating layer obtained in this comparative example had no ductility, and significant internal strain and microcracking were observed.
Moreover, there were many areas which were cloudy in appearance and did not exhibit uniform semi-smoothness. The internal strain of the plating film obtained in the example was 2900 to 3339b' (51
8 to 595k9/in2), whereas the internal strain obtained in the comparative example was 14500 to 290001b/in2.
(2589-5178k9'en).

Therefore, in some of the comparative examples, it was not possible to obtain a plated film that was uniformly semi-glossy and ductile, had little internal distortion, and was substantially free of microcracking, as was obtained in the examples. It will be readily understood that the embodiments shown above may be modified and modified in various ways without departing from the scope of the present invention.

Claims (1)

[Scope of Claims] 1. An electroplating bath suitable for electrodepositing semi-bright, ductile, and residual distortion-free nickel plating using an insoluble anode, the bath having a nickel content of 30 to 30% as nickel.
105 g/l nickel salt, 20-100 g/l electrolyte selected from boric acid and citric acid, 0 as brightener
．． Electroplating bath consisting of 25-3.0 g/l of ortho-formylbenzenesulfonic acid and 0.02-0.2 g/l of potassium perfluoroalkylsulfonate as wetting agent. 2. The electroplating bath according to claim 1, wherein the nickel salt is nickel sulfate. 3. The electroplating bath according to claim 1, wherein the electrolyte is boric acid. 4. An electroplating bath suitable for electrodepositing semi-bright, ductile, and residual distortion-free nickel plating using an insoluble anode;
105 g/l nickel salt, 20-100 g/l electrolyte selected from boric acid and citric acid, 0 as brightener
．． pH 2.5-4.5, electric current through an electroplating bath consisting of 25-3.0 g/l of ortho-formylbenzenesulfonic acid and 0.02-0.2 g/l of potassium perfluoroalkylsulfonate as wetting agent. Density 10
A method of electroplating nickel on a substrate by applying current between an insoluble anode and a cathode under conditions of 7A/Dm^2 or less and plating over a period of time until the desired nickel film thickness is achieved. 5. The electroplating method according to claim 4, wherein the current density is within a range of 10.8 to 64.8 A/Dm^2.