Electroplating of Sn-2.5Ag solders as 20 μm pitch micro-bumps

Author

Huang, Kuan-Chieh ; Chen, Jing-Yu ; Tsai, Ho-Cheng ; Lai, Chien-Lung ; Wu, Pu-Wei

Author_Institution

Dept. of Mater. Sci. & Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan

fYear

2010

fDate

20-22 Oct. 2010

Firstpage

1

Lastpage

4

Abstract

A Cu/Ni UBM and Sn-2.5Ag lead-free solder for 20 μm pitch micro-bump was successfully fabricated via consecutive electroplatings of Cu, Ni, and binary SnAg. Materials characterizations such as Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Electron Probe Micro-analyzer (EPMA), and X-ay Photoelectron Spectroscopy (XPS) were carried out to obtain relevant materials properties. We observed a strong effect of the plating current density on the resulting bump morphologies. After reflow, the solder revealed a spherical shape with a composition variation within 0.2 wt%.

Keywords

X-ray diffraction; X-ray photoelectron spectra; copper alloys; current density; electron probe analysis; electroplating; fine-pitch technology; lead alloys; nickel alloys; reflow soldering; scanning electron microscopy; silver alloys; solders; tin alloys; Cu-Ni; EPMA; SEM; Sn-Ag; UBM; X-ay photoelectron spectroscopy; X-ray diffraction; XPS; XRD; bump morphology; composition variation; consecutive electroplatings; electron probe micro-analyzer; lead-free solder; pitch micro-bumps; plating current density; reflow; scanning electron microscopy; solders; spherical shape; Copper; Current density; Electrodes; Morphology; Nickel; Surface morphology;

fLanguage

English

Publisher

ieee

Conference_Titel

Microsystems Packaging Assembly and Circuits Technology Conference (IMPACT), 2010 5th International

Conference_Location

Taipei

ISSN

2150-5934

Print_ISBN

978-1-4244-9783-6

Electronic_ISBN

2150-5934

Type

conf

DOI

10.1109/IMPACT.2010.5699591

Filename

5699591