Microstructural Evolution and Growth Morphology During Formation Process of Full Cu₃Sn Solder Joint in Microelectronic Packaging

• Main Authors: LIANG Xiao-bo, LI Xiao-yan, YAO Peng, LI Yang, JIN Feng-yang
• Format: Article
• Language: zho
• Published: Journal of Materials Engineering 2018-08-01
• Series: Journal of Materials Engineering
• Subjects: Cu₃Sn solder joint; Cu₆Sn₅; microstructural evolution; morphology
• Online Access: http://jme.biam.ac.cn/CN/Y2018/V46/I8/106
• ISSN: 1001-4381; 1001-4381

The full Cu₃Sn solder joint has been widely used in 3D packaging gradually. 270℃ and 1N were chosen as soldering temperature and pressure respectively to fabricate solder joints under different soldering time in order to analyze the process of microstructural evolution.Cu₆Sn₅ morphology with different soldering temperatures and time was also observed respectively to investigate the growth law of Cu₆Sn₅ and the effect of soldering temperature on the Cu₆Sn₅ morphology. The results show that scallop-like Cu₆Sn₅ is formed along the Cu substrate after 30min soldering, and a thin layer of Cu₃Sn is generated between Cu₆Sn₅ and Cu substrate.When the soldering time is increased to 60min, liquid Sn is totally consumed and Cu₆Sn₅ becomes a cohesive whole. With the increase of soldering time, Cu₃Sn grows at the expense of Cu₆Sn₅. Cu₆Sn₅ is totally transformed into Cu₃Sn up to 480min. The growing process of Cu₆Sn₅ includes nucleation, growth, fusion and covering up the big grain. With the increase of soldering temperature, the morphology of Cu₆Sn₅ changes from polyhedron shape to procumbent.