A method of forming a solder alloy deposit on a substrate comprising the following steps: i) provide a substrate 101 including a surface bearing electrical circuitry that includes at least one contact area 102, ii) form a solder mask layer 103 that is placed on the substrate surface and patterned to expose the at least one contact area 102, iii) contact the entire substrate area including the solder mask layer 103 and the at least one contact area 102 with a solution suitable to provide a metal seed layer 104 on the substrate surface wherein the metal seed layer 104 is selected from the group consisting of copper, copper-nickel alloy, copper-chromium alloy, copper-ruthenium alloy, copper-rhodium alloy, copper-silver alloy, copper-iridium alloy, copper-palladium alloy, copper-platinum alloy, copper-gold alloy and copper-rare earth alloy, copper-nickel-silver alloy, copper-nickel-rare earth metal alloy, copper/tin (bilayer), chromium/copper-chromium alloy/copper multilayer and nickel/tin/copper multilayer, iv) form a resist layer on the metal seed layer and create openings in the resist layer 105 which expose the solder mask openings 110 and the at least one contact pad 102, v) electroplate a first solder material layer 106 consisting of pure tin onto the metal seed layer 104, vi) electroplate a second solder material layer 107 consisting of a tin-silver alloy onto the first solder material layer 106, vii) remove the resist layer 105 and etch away an amount of the metal seed layer 104 sufficient to remove the metal seed layer from the solder mask layer area leaving two stacked solder material layers on the at least one contact area 102, viii) reflow the substrate and thereby forming a solder alloy deposit 108 from the metal seed layer 102, the first solder material layer 106 and the second solder material layer 107, wherein the composition of the solder alloy deposit 108 is controlled by the volumes of the metal seed layer 102, the first solder material layer 106 and the second solder material layer 107 and their respective elemental compositions and wherein the solder alloy deposit 108 contains more than 50 wt.-% of tin, 1 to 6 wt.-% of silver and 0.05 to 2 wt.-% of copper. i) provide a substrate 101 including a surface bearing electrical circuitry that includes at least one contact area 102, ii) form a solder mask layer 103 that is placed on the substrate surface and patterned to expose the at least one contact area 102, iii) contact the entire substrate area including the solder mask layer 103 and the at least one contact area 102 with a solution suitable to provide a metal seed layer 104 on the substrate surface wherein the metal seed layer 104 is selected from the group consisting of copper, copper-nickel alloy, copper-chromium alloy, copper-ruthenium alloy, copper-rhodium alloy, copper-silver alloy, copper-iridium alloy, copper-palladium alloy, copper-platinum alloy, copper-gold alloy and copper-rare earth alloy, copper-nickel-silver alloy, copper-nickel-rare earth metal alloy, copper/tin (bilayer), chromium/copper-chromium alloy/copper multilayer and nickel/tin/copper multilayer, iv) form a resist layer on the metal seed layer and create openings in the resist layer 105 which expose the solder mask openings 110 and the at least one contact pad 102, v) electroplate a first solder material layer 106 consisting of pure tin onto the metal seed layer 104, vi) electroplate a second solder material layer 107 consisting of a tin-silver alloy onto the first solder material layer 106, vii) remove the resist layer 105 and etch away an amount of the metal seed layer 104 sufficient to remove the metal seed layer from the solder mask layer area leaving two stacked solder material layers on the at least one contact area 102, viii) reflow the substrate and thereby forming a solder alloy deposit 108 from the metal seed layer 102, the first solder material layer 106 and the second solder material layer 107,