Investigation of Electromigration Reliability of Flip-chip Packages by Electrothermal Coupling Analysis

Abstract

The electromigration reliability of solder interconnects is dominated by current density and temperature inside the interconnects For flip-chip packages current densities around the regions where traces connect a solder bump increase by a significant amount owing to the differences in feature sizes and electric resistivities between the solder bump and its adjacent traces This current crowding effect along with induced Joule heating accelerates electromigration failures In this paper effects of current crowding and Joule heating in a flip-chip package are examined and quantified through a three-dimensional electrothermal coupling analysis We apply a volumetric averaging technique to cope with the current crowding singularity The volumetrically averaged current density and the maximum temperature in a solder bump are integrated in the Black’s equation to adjust the experimental electromigration fatigue lives In addition the effects of the solder bump structure Sn-37Pb and Sn-Ag-Cu solder bump composition and UBM composition on the electromigration characteristics are investigated

Date of Award	2018 Jul 6
Original language	English
Supervisor	Tei-Chen Chen (Supervisor)