FE IMPACTS ON SOLDER JOINT PROPERTIES IN MICROELECTRONIC ASSEMBLY

Abstract

LEAD-FREE SN BASED SOLDER MATERIALS HAVE BEEN USED FOR ELECTRONIC PACKAGING FOR MANY YEARS. THE CONVENTIONAL METHOD FORMING SOLDER/SUBSTRATE BOND IS OVEN REFLOW, WHICH THE WHOLE DEVICE WILL GO THROUGH HEATING PROCESS IN OVEN. HOWEVER, THE HIGH TEMPERATURE MELTING PROFILE FOR LEAD-FREE SOLDER MAY ARISE SEVERAL ISSUES. FIRST, THERE CAN BE A WARPAGE TO THE PLASTIC PART OF THE DEVICE. ALSO, THE COEFFICIENT OF THERMAL EXPANSION DIFFERENCES BETWEEN MATERIALS CAN LEAD TO MISMATCH. LASTLY, THE HIGHER REFLOW PROFILE MAY LEAD TO EXCESSIVE INTERMETALLIC COMPOUND (IMC) GROWTH, WHICH IS UNDESIRABLE IN SOLDER BONDING. MAGNETIC INDUCTION HEATING IS ONE OF THE VIABLE SOLUTIONS TO IMPROVE THE REFLOW PROCESS. FERROMAGNETIC MATERIALS-CENTRIC SAC, THEIR PROCESSES AND LOW-FREQUENCY MAGNETIC INDUCTION METHODOLOGY ARE EXPLORED IN RECENT YEARS FOR PRECISE AND RAPID REFLOW TO ENABLE SOLDER-SUBSTRATE INTERFACE RELIABILITY ADVANCEMENT. THE PRECISION AVOIDS DAMAGE TO THE PLASTIC CONSTITUENTS. MOREOVER, THE FAST H