To inhibit the consumption of Cu during multiple reflows of Pb-free on Cu

Abstract

We report an effective approach to inhibit the consumption of Cu during multiple reflows of SnAg2.3 solder on Cu. By depositing a very thin layer of the solder on Cu and followed by a 10-min reflow, the scallop-type morphology of the interfacial Cu 6 Sn 5 intermetallic compounds (IMCs) became flat and the channels between them closed up. When additional solder was deposited on the sample and reflowed again, the consumption of Cu as well as the growth the IMCs was retarded.