Electromigration　(EM)　behavior　of　eutectic　Sn-Bi　modified　with　cage-type　polyhedral　oligomeric　silsesquioxane　(POSS)　trisilanol　was　investigated.　A　direct　current　(DC)　was　applied　to　solder　joints　newly　designed　for　uniform　current　distribution　throughout　the　joint.　For　this　study,　a　current　density　of　10(4)　A/cm(2)　was　applied　at　25A　degrees　C　and　50A　degrees　C.　The　evolution　of　surface　and　interior　microstructure　due　to　current　stressing　was　observed　periodically　using　optical　and　scanning　electron　microscopy.　The　results　revealed　that　the　EM　behavior　was　retarded　significantly　in　solder　joints　with　the　addition　of　POSS　trisilanol.　Different　from　eutectic　Sn-Bi　solder　joints,　no　continuous　hillocks　formed　at　the　anode　side　and　no　cracks　occurred　at　the　cathode　side　in　solder　joints　modified　with　POSS　trisilanol　even　after　336　h　of　current　stressing　at　25A　degrees　C.　In　addition,　the　accumulation　of　Bi/Sn　phases　at　regions　near　the　anode/cathode　was　also　effectively　limited.　Joints　stressed　at　50A　degrees　C　also　exhibited　similar　behavior.　It　is　postulated　that　POSS　trisilanol　near　the　phase　boundary　provided　significant　restriction　to　the　mass　transport　due　to　DC　current　stressing.