Study on Electromigration of Flip-Chip Solder Interconnect
As the trend of miniaturization of complex integrated circuit(IC) devices, the current density of flip-chip solder bumps have increased significantly and each solder joint is supporting a current density close to or even over 104 A/cm2 .Therefore, in SnPb eutectic solder, which has a high diffusivity at the operating temperature due to its low melting point, the electromigration becomes a major reliability threat.
Thus, the thesis is aimed to investigate the effects of electromigration behavior on flip-chip package eutectic Sn-Pb solder bumps reliability under high current density. The current densities are 2x104 A/cm2 and 1.5x104 A/cm2,the surface of die temperatures are 115¢Jand 95¢J.The bump temperature, the histories of the bump resistance, and mean time to failure (MTTF) testings were conducted. The failure mechanism was observed through SEM and EDS.
From the results of the experiment, the dominant failure mode of the bump is due to electromigration behavior that causes voids at UBM/bump interface (cathode) when the sample¡¦s failure time is shorter. As the failure time is longer, the failure is also resulted from heat effect in addition to electromigration behavior.
Advisor:Jenq-Dah Wu; Ming-Hwa Jen; Chorng-Fuh Liu; Jao-Hwa Kuang
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:electromigration solder bump flip chip packages
Date of Publication:07/09/2004