The　trend　of　miniaturization　of　electronic　products　induced　the　shrinking　dimension　of　interconnects　in　the　chip.　When　those　interconnects　are　subjected　to　high　current　density　(usually　10(3)　to　10(4)　A/cm(2)),　electromigration　(EM)　could　affect　the　reliability　of　the　chip　which　would　ultimately　break　the　circuit.　In　this　study,　eutectic　SnPb　solders　with　thickness　of　280,　128,　and　50　mu　m　were　investigated　under　high　current　density　(10(4)　A/cm(2))　and　high　ambient　temperature　(120　degrees　C).　The　EM-induced　surface　undulations　were　more　prominent　at　the　shorter　thickness,　demonstrating　that　the　diffusion　of　metal　atoms/ions　was　controlled　by　the　actual　temperature　in　the　bulk　solder　instead　of　the　back　stress.　Bamboo　groove　features　were　observed　on　the　surface　of　solder　extrusion　at　the　anode　side　for　the　three　solder　thickness,　which　indicated　the　metal　atoms/ions　that　migrated　parallel　to　the　direction　of　flow　of　electrons.