Lookup NU author(s): Dr Stevin Pramana
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
A micromechanism of thermosonic gold wire bonding was elaborated by examining its interfacial characteristics as a result of the bonding process, including the fragmentation of the native aluminum oxide layer on Al pads, and formation of initial intermetallic compounds (IMCs). It is found that the existence of an approximately 5 nm thick native oxide layer on original Al pads has a significant effect on the bonding, and the nucleation of IMCs during the bonding process must overcome this relatively inert thin film. Bonding strength was fundamentally determined by the degree of fragmentation of the oxide films, through which the formation of IMCs can be initiated due to the direct contact of the metal surfaces to be bonded. The extent of fracture the oxide layer was strongly influenced by the level of ultrasonic power, as at its high level alumina fragmentation becomes pervasive resulting in contiguous alloy interfaces and robust bonds. The IMCs formed at the interfaces were identified as Al 4 Al and AuAl2 with a thickness of 150-300 nm. The formation mechanism of such IMCs was explained by the effective heat of formation theory. © 2010 American Institute of Physics.
Author(s): Xu H, Liu C, Silberschmidt VV, Pramana SS, White TJ, Chen Z, Sivakumar M, Acoff VL
Publication type: Article
Publication status: Published
Journal: Journal of Applied Physics
Print publication date: 01/12/2010
ISSN (print): 0021-8979
ISSN (electronic): 1089-7550
Publisher: AIP Publishing
Altmetrics provided by Altmetric