DocumentCode :
3507323
Title :
Influences of the initial thickness of the interfacial IMC layer on electromigration behavior of Cu/Sn/Cu microscale joints
Author :
Wu Yue ; Hong-Bo Qin ; Min-Bo Zhou ; Guang-Sui Xu ; Shan-Shan Cao ; Xiao Ma ; Xin-Ping Zhang
Author_Institution :
Sch. of Mater. Sci. & Eng., South China Univ. of Technol., Guangzhou, China
fYear :
2012
fDate :
13-16 Aug. 2012
Firstpage :
1320
Lastpage :
1325
Abstract :
The rapid development of modern electronic devices and products has proposed a great demand for the continuous scaling down in the dimension of solder joints and interconnect pitches in packaging; accordingly the current density in solder interconnects gets higher and higher. The higher current density can easily result in electromigration (EM) which has been regarded as a serious reliability issue. It is common that the thicknesses of the interfacial IMC layers at both interfaces of an as-reflowed solder interconnect are different. In this study, the effect of the initial IMC thickness on the EM behavior of solder interconnects was investigated by SEM/EDX/FIB. In order to clarify the influence of the initial thickness of interfacial IMC layers on EM behavior, the joint samples were divided into two types, A and B, i.e., the Type-A joints have a thick interfacial IMC layer at the cathode interface, while the Type-B joints have a thick one at the anode interface. The results show that after current stressing the thickness of the thick IMC layer at the cathode interface of Type-A joints decreases obviously, while the thin IMC layer at the cathode interface of Type-B joints hardly changes. The results of the FIB/SEM analysis show that Kirkendall voids occurred near the IMC/Cu interface at the anode of Type-A joints, whereas hardly seeing the voids in Type-B joints. The analyzed results show that the faster dissolution of IMC layer at the cathode of Type-A joints is caused by the higher joule heating and the higher EM flux; the Kirkendall voids at the anode of Type-A joints are caused by the higher backstress gradient.
Keywords :
X-ray chemical analysis; copper alloys; electromigration; focused ion beam technology; integrated circuit interconnections; integrated circuit packaging; scanning electron microscopy; solders; tin alloys; Cu-Sn-Cu; Kirkendall voids; SEM-EDX-FIB analysis; as-reflowed solder interconnect; backstress gradient; cathode interface; electromigration behavior; energy dispersive X-ray spectroscopy; focused ion beam; interconnect pitches; interfacial IMC layer; microscale joints; modern electronic devices; modern electronic products; reliability issue; scanning electron microscope; solder interconnects; type-A joints; type-B joints; Abstracts; Educational institutions; Heating; Joints; Soldering; Testing; Tin;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electronic Packaging Technology and High Density Packaging (ICEPT-HDP), 2012 13th International Conference on
Conference_Location :
Guilin
Print_ISBN :
978-1-4673-1682-8
Electronic_ISBN :
978-1-4673-1680-4
Type :
conf
DOI :
10.1109/ICEPT-HDP.2012.6474849
Filename :
6474849
Link To Document :
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