High solder joint reliability with lead free solders

Recently. preventing environmental pollutions. lead-free (Pb-free) soldcrs are about to replace tin-lead (Sn-Pbj eutectic solders. Sn-Ag-Cu alloys arc lcading candidatcs for lead free solders. However. Sn-Ag-Cu alloys were not satisfied to meet sever custoiner requirements. At first, optimum silver wt%