Study of Electro-migration for Flip-Chip Solder bumps with 50um CuNi/SnAg

• Main Authors: Chiang, Shih-Kuan, 江詩寬
• Other Authors: Chen, Chih
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/93699012805719883397

碩士 === 國立交通大學 === 工學院半導體材料與製程設備學程 === 99 === Flip-chip technology has become a mainstream trend in advanced electronic packaging because of its capability of higher I/O density and smaller package size. With higher current and smaller size trends, electromigration in flip-chip solder has become an critical of reliability concern. Activation energy of electromigration is investigated in eutectic SnAg flip-chip solder joints with thick under-bump-metallizations (UBMs) of 5-μm Cu/3-μm Ni. We fabricate the Kelvin probes to monitor the bump resistance during the current stressing, and define the electromigration failure as the bump resistance increase reaches 20% of its initial value. Most of the previous studies defined the failure of the electromigration when the stressing circuit was open. In this study, we fabricated SnPb solder joints with under-bump-metallizations (UBMs) of Cu /Ni. The sample were subjected to electromigration tests by 0.5A &0.6A at 170℃. The electromigration behavior and the mechanism which cause the damage of the bumps were been monitored at various stages of electromigration. The Kevin probes were employed to monitor the changes for the bump resistance during the electromigration tests and the mechanisms which cause damage to the joints were discussed for these two different currents, respectively.