Wire bondability of Au/Ni bond pads: effects of metallisation schemes and processing conditions

Author

Chan, Yu Hin ; Kim, Jang-Kyo ; Liu, Deming ; Liu, Peter C K ; Cheung, Yiu Ming ; Ming Wai

Author_Institution

Dept. of Mech. Eng., Hong Kong Univ. of Sci. & Technol., Kowloon, China

fYear

2002

fDate

4-6 Dec. 2002

Firstpage

69

Lastpage

76

Abstract

The wire bondability and surface characteristics were studied of Au/Ni bond pads on organic FR-4 PCBs with different gold plating schemes and gold thickness. Three different plating techniques were used to deposit gold layers, namely the electrolytic gold plating, immersion gold plating and immersion gold plating followed by electrolytic gold plating. Process windows for the individual metallisation schemes were established to optimize the wire bond force and bond power. Bond performance after wire bonding was evaluated based on the wire pull strength and wire deformation ratio. Various elemental and surface characterization techniques, such as SEM, optical profiler, XPS, nano-hardness test and surface energy analysis, were employed to characterize the bond pad surfaces, which were then correlated to the wire bond performance. The effects of plasma treatment using Ar and O₂ gases were also studied.

Keywords

X-ray photoelectron spectra; electroplating; gold; integrated circuit metallisation; integrated circuit packaging; lead bonding; microhardness; nickel; plasma materials processing; scanning electron microscopy; surface cleaning; surface energy; surface morphology; Ar; Au-Ni; Au/Ni bond pads; O₂; SEM; XPS; bond pad wire bondability; bond power; electrolytic gold plating; gold thickness; immersion gold plating; metallisation; nano-hardness test; optical profiler; organic FR-4 PCB; plasma cleaning; plasma treatment; surface characterization; surface energy analysis; wire bond force optimization; wire bond performance; wire bonding; wire deformation ratio; wire pull strength; Argon; Bonding forces; Gases; Gold; Metallization; Performance analysis; Plasmas; Surface treatment; Testing; Wire;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Materials and Packaging, 2002. Proceedings of the 4th International Symposium on

Print_ISBN

0-7803-7682-X

Type

conf

DOI

10.1109/EMAP.2002.1188815

Filename

1188815