TY - GEN
T1 - Non-destructive Observation of Void Formation Due to Electromigration in Solder Microbump by 3D X-ray
AU - Shie, Kai Cheng
AU - Lin, Tzu Wen
AU - Tu, King-Ning
AU - Chen, Chih
N1 - Publisher Copyright:
© 2021 IEEE
PY - 2021
Y1 - 2021
N2 - Due to the shrinkage of solder microbumps diameter for higher I/Os, the failure analysis of electromigration (EM) in solder microbumps is more and more important for 3D IC packaging. The non-destructive observation method through 3D X-ray was adopted to study voids formation and necking during EM. A daisy-chain test vehicle with the number of 400 solder microbumps was under current density of 8 x 104 A/cm2 at 150 °C. The structure of solder microbump was Cu/Sn2.3Ag/Ni/Cu. With the non-destructive observation method, the evolution of EM failures can be analyzed when the resistance change was 0 %, 5 %, 10 %, and 20 %. Therefore, the process of void formation was easily to be discovered through different view angles of computed tomography (CT). However, resolution of 3D X-ray was about a micrometer, destructive analysis of cross-section BEI was done after EM test. By comparison of CT images and BEI, the limitation of CT images could be known. Additionally, some solder microbumps were not damaged seriously due to the effect of Sn grain orientation. Through EBSD analysis, the orientation of Sn grain was measured. The results show that when the c-axis of residual solder was nearly perpendicular to electron current direction, EM damage can be retarded.
AB - Due to the shrinkage of solder microbumps diameter for higher I/Os, the failure analysis of electromigration (EM) in solder microbumps is more and more important for 3D IC packaging. The non-destructive observation method through 3D X-ray was adopted to study voids formation and necking during EM. A daisy-chain test vehicle with the number of 400 solder microbumps was under current density of 8 x 104 A/cm2 at 150 °C. The structure of solder microbump was Cu/Sn2.3Ag/Ni/Cu. With the non-destructive observation method, the evolution of EM failures can be analyzed when the resistance change was 0 %, 5 %, 10 %, and 20 %. Therefore, the process of void formation was easily to be discovered through different view angles of computed tomography (CT). However, resolution of 3D X-ray was about a micrometer, destructive analysis of cross-section BEI was done after EM test. By comparison of CT images and BEI, the limitation of CT images could be known. Additionally, some solder microbumps were not damaged seriously due to the effect of Sn grain orientation. Through EBSD analysis, the orientation of Sn grain was measured. The results show that when the c-axis of residual solder was nearly perpendicular to electron current direction, EM damage can be retarded.
KW - 3D X-ray
KW - Electromigration
KW - Non-destructive observation
KW - Solder microbump
KW - Tin grain orientation
UR - http://www.scopus.com/inward/record.url?scp=85124675294&partnerID=8YFLogxK
U2 - 10.1109/ECTC32696.2021.00153
DO - 10.1109/ECTC32696.2021.00153
M3 - Conference contribution
AN - SCOPUS:85124675294
T3 - Proceedings - Electronic Components and Technology Conference
SP - 925
EP - 930
BT - Proceedings - IEEE 71st Electronic Components and Technology Conference, ECTC 2021
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 71st IEEE Electronic Components and Technology Conference, ECTC 2021
Y2 - 1 June 2021 through 4 July 2021
ER -