Pei-Tzu Lee¹, Wan-Zhen Hsieh², Cheng-Yu Lee³, Xiao-Yun Li², Shao-Chin Tseng², Mau-Tsu Tang², Ching-Shun Ku², C. Robert Kao¹, Cheng-En Ho³; ¹National Taiwan University, ²National Synchrotron Radiation Research Center, ³Yuan Ze University

Electromigration and Sn whisker growth both played key roles in microelectronic packaging reliability for past decades and a dynamic observation on these two issues are still quite lacking to date. In this study, we conducted a real-time analysis on Sn electromigration behavior and Sn whisker growth in a Blech structure via nano-X-ray fluorescence (nano-XRF) microscopy (beamline 23A, Taiwan Photon Source) and white X-ray nanodiffraction (beamline 21A, Taiwan Photon Source). The Sn depletion at the cathode and the Sn whisker/extrusion formation at the anode upon electron current stressing were in-situ characterized using nano-XRF, and the residual deviatoric strains of Sn films after electromigration were analyzed using white Laue diffraction. The knowledge would greatly advance our fundamental understandings of Sn electromigration/whiskering mechanisms. Details will be presented in this talk.