Title :
The evolution of interfacial microstructure of Sn3.5Ag solder bump with Cu under-bump metallization
Author :
Bi, Jinglin ; Hu, Anmin ; Li, Ming ; Mao, Dali
Author_Institution :
Lab. of Microelectron. Mater. & Technol., Shanghai Jiao Tong Univ., Shanghai, China
Abstract :
Low cost electrodeposited Sn3.5Ag solder bumps fabrication technology was developed for three-dimensional packaging applications. Effect of reflow time on interfacial reaction of electroplated Sn3.5Ag solder bumps with Cu under-bump metallization (UBM) was investigated. The microstructure of eutectic Sn3.5Ag is composed of β-Sn phase and Ag3Sn IMCs in the solder region. At the interface between solder and Cu, scallop-like Cu-Sn IMCs were formed toward solder region and were identified as Cu6Sn5 IMCs by compositional measurement of EDX. XRD measurement identified that Cu6Sn5 and Ag3Sn formed after reflowing for lmin, and as the reflow time extended the quantity of Ag3Sn almost remained the same while the quantity of Cu6Sn5 increased. No Cu3Sn was detected, even after reflowing for 20min. EDX analysis was consistent with the XRD result.
Keywords :
X-ray diffraction; copper alloys; electrodeposition; eutectic alloys; integrated circuit metallisation; integrated circuit packaging; reflow soldering; silver alloys; solders; three-dimensional integrated circuits; tin alloys; Cu; CuSn; SnAg; X-ray diffraction; electrodeposition; eutectic alloys; interfacial microstructure; reflow time; solder bumps fabrication; three-dimensional packaging; underbump metallization; Copper; Metallization; Microstructure; Packaging; Silver; Tin; X-ray scattering;
Conference_Titel :
Electronic Packaging Technology and High Density Packaging (ICEPT-HDP), 2011 12th International Conference on
Conference_Location :
Shanghai
Print_ISBN :
978-1-4577-1770-3
Electronic_ISBN :
978-1-4577-1768-0
DOI :
10.1109/ICEPT.2011.6066855
