The composition of intermetallic compounds in Sn-Ag-Bi-In solders on Cu substrates

摘要

84Sn-3Ag-3Bi-10In and 89Sn-3Ag-3Bi-5In solders were subjected to reflow and solid state aging. The intermetallic compounds that formed at the interfaces between the solders and the Cu substrates and those that formed in the bulk solders in both test conditions were investigated. In the as-reflow samples, the intermetallic compounds were identified as Cu3Sn and Cu6Sn5. After solid state aging, these compounds became Cu6(Sn,In)5 and Cu3(Sn,In). The compounds that formed in the bulk solders were ?? phase, the solid solution of Ag3Sn and Ag2In.