Measurement of electromigration activation energy of eutectic SnPb flip-chip solder joints with Cu/Ni and Cu thick-film Under-bump-metallization

• Main Authors: Tsung-Hsien Chiang, 江宗憲
• Other Authors: Chih Chen
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/11294300642094756292

碩士 === 國立交通大學 === 材料科學與工程系所 === 96 === Activation energy of electromigration is investigated in eutectic SnPb flip-chip solder joints with thick under-bump-metallizations (UBMs) of 5-μm Cu/3-μm Ni and 5-μm Cu. 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. The current stressings were done on a hotplate with temperatures at 160oC, 150oC, and 140oC, and the applied current was 0.9 A. The failure mechanisms of different UBM structures are examined. The joule heating of the solder joints during electromigration test was measured by using Kelvin probes and aluminum Temperature coefficient resistivity effect. This approach provides a better way of studying joule heating due to electromigration test in flip chip solder joints. The activation energy was measured to be 1.52 and 0.84 eV for the eutectic SnPb solder joints with the Cu/Ni and Cu UBMs, respectively.