Characterization of Electromigration-Induced Degradation in Microbumps via On-Chip Embedded Temperature Sensors Under High Current Density

This study investigates electromigration-induced degradation in microbumps through an integrated experimental and computational approach. Platinum thin-film temperature sensors were embedded within flip-chip specimens to enable real-time thermal monitoring. Internal package temperatures were measured using these sensors, with validation via infrared thermography, to quantitatively characterize Joule heating effects under high-current-density conditions. Cross-sectional SEM analysis of specimens subjected to accelerated current stressing revealed that electromigration drives two concurrent failure mechanisms in electrothermal coupling environments: 1) void nucleation-propagating along intermetallic compound (IMC)/solder boundaries and 2) necking caused by accelerated solder consumption. A multiphysics modeling framework combining unified creep plasticity (UCP) constitutive laws with the J-integral fracture mechanics method was developed to simulate shear deformation evolution in microbumps containing electromigration-induced voids. Computational results demonstrated that void propagation disrupts hydrostatic stress uniformity, inducing localized stress concentrations near solder-depleted regions. Crucially, solder consumption-induced voids exhibited higher stress intensification compared to IMC-interface voids, establishing a direct correlation between void topology and mechanical reliability degradation.