Electrolytic gold plating solution, method of manufacturing the same, gold plating method and gold complex

Abstract

Provided is an electrolytic gold plating solution that does not contain cyanide, has excellent oxidation stability, and exhibits good current efficiency during gold plating. The electrolytic gold plating solution uses a gold complex as a gold source, and contains a chelating agent, a conductive salt, and a buffer agent, wherein the gold complex has a structure in which a hydantoin compound represented by general formula (1) is coordinated to a monovalent gold ion. In formula (1), R1 to R4 each independently represent a hydrogen atom or a monovalent organic group; two or either of R1 and R2 arehydrogen atoms; and two or either of R3 and R4 are hydrogen atoms. However, the case where R1 is a methyl group and R2 to R4 are all hydrogen atoms is excluded.

Description

technical field [0001] The present invention relates to an electrolytic gold plating solution used for gold plating of wafers, substrates, etc., its production method, and a gold plating method, and further relates to a gold complex that can be used as a raw material of the electrolytic gold plating solution. Background technique [0002] Conventionally, as a plating solution used in electrolytic plating and electroless plating, a cyanide-based gold plating solution using a gold cyanide complex having excellent oxidation stability in the solution as a gold supply source has been conventionally used. However, since the cyanide-type gold salt is highly toxic, there is a problem that it is not preferable from the viewpoint of handling safety and waste water treatment. In addition, when a cyanide-based gold plating solution is used, there is also a problem that it is difficult to form a fine circuit pattern because the remaining cyanide peels off and damages the resist pattern o...

AI Technical Summary

Problems solved by technology

[0004] However, the gold salts or gold complexes contained in these non-cyanide gold plating solutions lack oxidation stability, and there is a problem of decomposition during the plating operation

For example, in the above-mentioned gold sulfite, the sulfite ion in the solution is easily oxidatively decomposed due to the dissolved oxygen in the plating solution and the air introduced due to stirring or the entry and exit of the plated object, so that its concentration is reduced, Therefore, the oxidation stability of the gold complex is reduced, and the decomposition of the plating solution sometimes occurs

Moreover, when such decomposition occurs, gold precipitation in the plating solution and gold sinking in precipitation occur in the plating solution tank or piping, which hinders the plating operation.

Therefore, compared to non-cyanide electrolytic plating, although additives such as stabilizers or complexing agents are added to the plating solution to prevent the decomposition of the plating solution for plating treatment, such measures will make the stabilizer The cost and manufacturing steps of the plating solution become complicated, so its cost will increase

[0005] In addition, plating solutions containing gold salts or gold complexes with low oxidation stability are also problematic from the viewpoint of their storage.

In the case of the above-mentioned gold sulfite, black deposits are likely to occur due to the decomposition of the gold salt during storage, so it must be stored in a light-shielding state, and its management is not easy

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