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

fYear

2011

fDate

8-11 Aug. 2011

Firstpage

1

Lastpage

5

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;

fLanguage

English

Publisher

ieee

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

Type

conf

DOI

10.1109/ICEPT.2011.6066855

Filename

6066855