Patent ID: 8809181

Claim:
A method comprising: depositing a plurality of solder balls on a plurality of pads of a package substrate, the plurality of solder balls corresponding with the plurality of pads; performing a first solder reflow process to form a solder joint between the plurality of solder balls and the plurality of pads, wherein individual solder balls of the plurality of solder balls include a first solder material and a second solder material, the first solder material having a liquidus temperature that is greater than a peak temperature of the first solder reflow process and the second solder material having a liquidus temperature that is less than the peak temperature of the first solder reflow process; and performing a second solder reflow process to form a solder joint between the plurality of solder balls and a circuit board, wherein the first solder material is an off-eutectic alloy having a liquidus temperature that is greater than a peak temperature of the second solder reflow process and a solidus temperature that is less than the peak temperatures of the first solder reflow process and the second solder reflow process, and the second solder material has a liquidus temperature that is less than the peak temperature of the second solder reflow process.