The effects of laser reflow conditions on the formation of intermetallic compounds at Sn3.0Ag0.5Cu solder/Cu joint interface

This paper presents intermetallic compounds formation at the interface between the Sn3.0Ag0.5Cu solder and Cu pad during a first laser reflow, and then followed by a second hot air reflow processes. Cu3Sn was observed at the laser reflow solder joints, and its morphology was strongly dependent on the laser reflow power and heating time applied. The compound was formed in the first laser reflow process also changed after the secondary hot air reflow process. Cu6Sn5 was formed in the joint after the secondary hot air reflow process, and it was found that the morphology of intermetallic compound formed by the second hot air reflow were also affected by the conditions of the first laser reflow.