Study of Suitable Palladium and Gold Thickness in ENEPIG Deposits for Lead-Free Soldering and Gold Wire Bonding

摘要

Tem analysis was conducted on test pieces that were aged at 150℃ for 1,000 hours after soldering Sn-3.0Ag-0.5Cu and Sn-3.5Ag to ENEPIG deposits.rnFor Sn-3.0Ag-0.5Cu solder, an alloy layer (Cu,Ni) 6Sn5 with even palladium distribution was identified as the main layer. On the other hand, Sn-3.5Ag solder, revealed a distinct columnar alloy layer (Pd, Ni) Sn4 on the uniform alloy layer Ni3Sn4.rnThe alloy layer (Pd, Ni) Sn4 apparently degrades solder joint reliability. In addition, solder joint reliability was more dependent on palladium deposit thickness than gold deposit thickness, so it was essential to control the palladium deposit thickness.