Study of interfacial reactions and mechanism properties between SAC and SACNG lead free solders with Au/Ni/Cu in BGA package

• Main Authors: Yu-Cheng Chiang, 江昱成
• Other Authors: Yee-wen Yen
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/06574119292091409988

碩士 === 國立臺灣科技大學 === 化學工程系 === 96 === Abstract Element of Cu、Ni and Ag as substrate have been widely used for electronic packaging industry. In bonding process, the element diffusion between solders and substrate will grows brittle intermetallic compound (IMCs) at the interface. Because it has different compositions and local equilibrium inside. The IMCs provides heterogenous connection； however, the reliability is affected by the thickness of IMCs .An addition of little element in solders is important factor for solder properties and interfacial reaction. Therefore, this study investigate interfacial reaction and reliability between Sn-3.0Ag-0.5Cu (SAC305)、Sn-4.0Ag-0.5Cu (SAC405) 、Sn-4.0Ag-0.5Cu-0.05Ni-0.01Ge (SACNG) and Au/Ni/Cu substrate . In the interfacial reaction, (Cu,Ni,Au)6Sn5 and (Ni,Cu,Au)3Sn4 phases were formed at the interface, while the AuSn4 phase was observed within the solders in all couples. After heating treatment, (Cu,Ni,Au)6Sn5 and(Ni,Cu,Au)3Sn4 phases were observed to at the interface, but the AuSn4 phases vanished gradually with increasing reaction time. In all reaction process no Ge element IMCs were formed at the interface and within solders in Sn-4.0Ag-0.5Cu-0.05Ni-0.01Ge (SACNG). With respect to reliability, the strength decreased as the time of heating treatment increased. After heating treatment, the strength of SACNG solder was higher that those of SAC305 and SAC405. Furthermore, The fracture morphologies of SAC305 and SAC405 were transformed form solder-IMCs to IMCs only, nevertheless in SACNG, no such transformed was observed. The IMCs of fracture were(Cu, Ni)6Sn5 phase in all solders.