Patent ID: 7179362

Claim:
An acidic, aqueous electrolyte for depositing tin-copper alloys comprising one or more alkylsulfonic acids and/or alkanolsulfonic acids, one or more soluble tin (II) salts, one or more soluble copper (II) salts, and one or more organic sulfur compounds, characterized in that the organic sulfur compounds comprise one or more thioether functions and/or ether functions of the general formula —R—Z—R′-as structural features, with Z representing a sulfur atom or an oxygen atom, and R and R′ being the same or different non-aromatic organic radicals on the condition that at least one of the radicals R and R′ comprises at least one sulfur atom if Z is exclusively an oxygen atom and said tin-copper alloy comprises copper in an amount of 0.1 to 99.9 wt-%.