Briefly, a novel material process is disclosed wherein one or more nucleation modifiers are added, in trace amounts, to a lead-free tin-rich solder alloy to produce a solder composition with reduced or suppressed undercooling temperature characteristics. The modifier being a substance which facilitates the reduction of extreme anisotropic properties associated with body-centered-tetragonal tin based lead-free solder. The addition of the nucleation modifiers to the solder alloy does not materially effect the solder composition's melting point. As such, balls of solder with the nucleated composition freeze while other solder balls within the array remain in the melt. This effectively enables one substrate to be pinned to another substrate by one or more predetermined solder balls to secure the package while the remaining solder joints are in the liquid state.