Characterization of intermetallic compounds in Cu-Al ball bonds: thermo-mechanical properties, interface delamination and corrosion
conference paper
In high power automotive electronics copper wire bonding is regarded as the most promising alternative for gold wire bonding in 1st level interconnects. In the Cu-Al ball bond interface the growth of intermetallic compounds can deteriorate the electrical and mechanical properties of the interconnection. A summary of the thermo-mechanical properties of Cu-Al intermetallic compounds is given. Delamination experiments were performed to study interfacial cracking in the Cu-Al system. Interfacial delamination initiates in the Al-rich intermetallics (CuAl, CuAl2) and propagates easily into other intermetallic layers. The Cu9Al4 - Cu s.s. is also found to be susceptible for delamination fracture. To quantify the corrosion and oxidation sensitivity of Cu-Al intermetallics 8 different aging experiments under various conditions (At, AT, air or halogen-rich solution or combined) were performed. In all cases the oxidation/corrosion attack at the non-equilibrium Cu s.s. -interface with the Cu-Al intermetallics is more severe than of a homogeneous bulk solid solution of aluminum in copper (with more than 5 wt% Al). The oxidation/corrosion attack is even more severe than for pure copper.
Topics
TNO Identifier
507173
ISBN
9781467346450
Publisher
IEEE Computer Society
Article nr.
6542123
Source title
4th Electronic System-Integration Technology Conference, ESTC 2012, 17-20 September 2012, Amsterdam, Netherlands
Files
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