Pb-FREE SOLDER BUMPS WITH IMPROVED MECHANICAL PROPERTIES

摘要

PROBLEM TO BE SOLVED: To provide a method of forming Pb-free solder bumps with improved mechanical properties and to provide a semiconductor device using the same.SOLUTION: There is provided a semiconductor substrate having a first contact and an undoped electroplated lead-free solder bump 610 formed on the first contact. There is also provided a device package substrate having a second contact and a doped lead-free solder layer 510 containing dopant on the second contact. The dopant reduces a solidification undercooling temperature of the undoped lead-free solder bump when the dopant is incorporated into the lead-free solder bump. The undoped electroplated lead-free solder bump and the doped lead-free solder layer are melted thereby incorporating the dopant into the undoped lead-free solder to form a doped solder bump 140. The solder bump provides an electrical connection between the first contact and the second contact.