Abstract: The present invention concerns an electroless gold plating bath comprising a) gold ions; b) sulfite ions; c) iodide ions; d) at least one phosphonate compound according to formula (1) wherein each X is independently an alkanediyl group; R1, R2, R3 and each R4 are independently alkanediyl groups; M is independently hydrogen, a metal atom or a cation forming radical; each n is a rational number and selected in accordance with the valency of the respective M; and b is an integer ranging from 1 to 10. The invention further is directed to the use of the bath and a method for depositing a gold layer on a surface of a substrate. The bath is particularly suitable in the manufacture of printed circuit boards, IC substrates, semiconducting devices, interposers made of glass and the like.

Abstract: The present invention concerns an electroless gold plating bath comprising a) gold ions; b) sulfite ions; c) iodide ions; d) at least one phosphonate compound according to formula (1) wherein each X is independently an alkanediyl group; R1, R2, R3 and each R4 are independently alkanediyl groups; M is independently hydrogen, a metal atom or a cation forming radical; each n is a rational number and selected in accordance with the valency of the respective M; and b is an integer ranging from 1 to 10. The invention further is directed to the use of the bath and a method for depositing a gold layer on a surface of a substrate. The bath is particularly suitable in the manufacture of printed circuit boards, IC substrates, semiconducting devices, interposers made of glass and the like.

Abstract: An electroless aqueous gold plating bath, comprising at least one source of gold ions and at least one reducing agent for gold ions, characterized in that it comprises at least one ethylenediamine derivative as plating enhancer compound according to formula (I) wherein the residues R1 and R2 comprise 2 to 12 carbon atoms and are selected from the group consisting of branched alkyl, unbranched alkyl, cycloalkyl or combinations thereof wherein the individual residues R1 and R2 are the same or different and a method of depositing of gold. The electroless aqueous gold plating bath is suitable to provide soft gold layers useful for wire bonding and soldering applications which are required for electronic components.

Abstract: A method and apparatus for regenerating a plating composition which is suitable for depositing at least one first metal on a substrate where the plating rate in the plating composition is very low, where the concentration of the at least one first metal in the plating composition cannot be easily set at a constant level, and where plating-out of the at least one first metal from the plating composition takes place. The method and apparatus for regenerating a plating composition is suitable for depositing at least one first metal on a substrate at a sufficiently high plating rate, while offering the opportunity to easily adjust the concentration of the at least one first metal in the plating composition at a constant level and to provide the plating composition with sufficient stability against decomposition thereof in order to safeguard the regeneration cell from plated-out first metal.

Abstract: A method and apparatus for regenerating a plating composition which is suitable for depositing at least one first metal on a substrate where the plating rate in the plating composition is very low, where the concentration of the at least one first metal in the plating composition cannot be easily set at a constant level, and where plating-out of the at least one first metal from the plating composition takes place. The method and apparatus for regenerating a plating composition is suitable for depositing at least one first metal on a substrate at a sufficiently high plating rate, while offering the opportunity to easily adjust the concentration of the at least one first metal in the plating composition at a constant level and to provide the plating composition with sufficient stability against decomposition thereof in order to safeguard the regeneration cell from plated-out first metal.

Abstract: A method and apparatus for regenerating a plating composition which is suitable for depositing at least one first metal on a substrate where the plating rate in the plating composition is very low, where the concentration of the at least one first metal in the plating composition cannot be easily set at a constant level, and where plating-out of the at least one first metal from the plating composition takes place. The method and apparatus for regenerating a plating composition is suitable for depositing at least one first metal on a substrate at a sufficiently high plating rate, while offering the opportunity to easily adjust the concentration of the at least one first metal in the plating composition at a constant level and to provide the plating composition with sufficient stability against decomposition thereof in order to safeguard the regeneration cell from plated-out first metal.

Abstract: A method and apparatus for regenerating a plating composition which is suitable for depositing at least one first metal on a substrate where the plating rate in the plating composition is very low, where the concentration of the at least one first metal in the plating composition cannot be easily set at a constant level, and where plating-out of the at least one first metal from the plating composition takes place. The method and apparatus for regenerating a plating composition is suitable for depositing at least one first metal on a substrate at a sufficiently high plating rate, while offering the opportunity to easily adjust the concentration of the at least one first metal in the plating composition at a constant level and to provide the plating composition with sufficient stability against decomposition thereof in order to safeguard the regeneration cell from plated-out first metal.