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TEM microstructural analysis of as-bonded copper ball bonds on aluminum metallization

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conference contribution
posted on 2009-09-23, 13:45 authored by Hui Xu, Changqing Liu, Vadim SilberschmidtVadim Silberschmidt, Zhong Chen
In this study, the nano-scale interfacial details of ultrasonic copper ball bonding to an aluminum metallization in the as-bonded states were investigated using high resolution scanning/transmission electron microscopy with energy dispersive spectroscopy. Our results showed that ultrasonic vibration swept aluminum oxide and copper oxide in some regions of contacting surface, where an approximate 20 nm Cu-Al intermetallics (i.e. CuAl2) formed. In the regions where oxide remained, aluminum oxide layer connected with copper oxides layer. No nano-level voids or gaps were observed at the central area of the interface, including the regions with oxide. Calculation of interfacial temperature showed that the ultrasonic vibration increased the flash temperature up to 465degC which was believed to improve the interdiffusion for the formation of Cu-Al intermetallics.



  • Mechanical, Electrical and Manufacturing Engineering


XU, H....et al., 2008. TEM microstructural analysis of as-bonded copper ball bonds on aluminum metallization. IN: 10th Electronics Packaging Technology Conference, (EPTC 2008), Singapore, 9-12 Dec., pp. 789 - 794 .




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