Both high Pb-Sn and eutectic 63Sn-37Pb have been the suitablematerials for the interconnection of electronic components because oftheir low cost and appropriate physical properties. Due to environmentalawareness, and the health hazards caused by the lead in the solders,large efforts have been made to develop a lead-free solderingtechnology. Among the large variety of lead-free solders the Sn-Agalloys are expected to be the best candidates. Furthermore, from areliability point of view, there has been interest in the improvedthermal fatigue resistance of solder interconnects. Therefore, in thisstudy two lead-free solder alloys (Sn96.5Ag3.5, Sn95.5Ag3.8Cu0.7) andtwo lead-containing solder alloys(Sn63Pb37 Sn59Pb40Agl) wereinvestigated and compared with each other in order to give an estimationof the reliability enhancement of the new lead-free solderingtechnology. These investigations were focused on mechanical and physicalproperties (coefficient of thermal expansion, stress-strain curves atdifferent strain-rates, ultimate strength) as well as on themicrostructural appearance of the solders
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