Interfacial reaction of a Sn-3.0Ag-0.5Cu thin film during solder reflow

Purpose - The purpose of this paper is to produce and investigate the interfacial reaction between Sn-3.0Ag-0.5Cu (SAC305) thin films and Cu substrates by solder reflow at various temperatures and times.Design methodology approach - SAC305 thin films were deposited on copper substrates using a thermal evaporation technique. The as-deposited SAC305 Cu was then reflowed on a hot plate at temperatures of 230, 240, 250 and 260°C for 30 s. In addition, solder reflow was conducted at a constant temperature of 230°C for 5, 10, 15 and 20 s. The microstructure, phase and thickness of the intermetallic compounds (IMCs) formed were determined after cross-sectional metallographic preparation.Findings - Cu6Sn5 and Cu3Sn were observed at the as-reflowed SAC305 Cu interfacial region. The IMC thicknesses increased with the higher reflow temperature and longer reflow times.Originality value - Up to now, studies on the thin film characteristics of SAC305 lead-free solder have been very limited. Thus, this paper presents the deposition of SAC305 thin film by a thermal evaporation technique and its characteristics after solder reflow.