Ultra-fine pitch palladium-coated copper wire bonding : effect of bonding parameters
Lim, Adeline B. Y.
Chang, Andrew C. K.
Gan, Chee Lip
Date of Issue2014
School of Materials Science and Engineering
Copper (Cu) wire bonding has become a mainstream IC assembly solution due to its significant cost savings over gold wire. However, concerns on corrosion susceptibility and package reliability have driven the industry to develop alternative materials. In recent years, palladium-coated copper (PdCu) wire has become widely used as it is believed to improve reliability. In this paper, we experimented with 0.6 ml PdCu and bare Cu wires. Palladium distribution and grain structure of the PdCu Free Air Ball (FAB) were investigated. It was observed that Electronic Flame Off (EFO) current and the cover gas type have a significant effect on palladium distribution in the FAB. The FAB hardness was measured and correlated to palladium distribution and grain structure. First bond process responses were characterized. The impact of palladium on wire bondability and wire bond intermetallic using a high temperature storage test was studied.
DRNTU::Engineering::Materials::Electronic packaging materials
© 2014 Elsevier Ltd. This is the author created version of a work that has been peer reviewed and accepted for publication by Microelectronics Reliability, Elsevier Ltd. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.microrel.2014.05.005].