Microstructure Studies of Under Bump Metallization Systems Using Transmission Electron Microscopy
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Abstract In this study, the interface reactions between eutectic SnPb solder and two Ni-based UBM systems are reported, namely the sputtered Cu/Ni(V)/Al and the electroless Au/Ni(P) systems. Comparisons are made to the conventional Au/Al ball bonding system in terms of microstructure evolution, and metallurgical stability. TEM sample preparation is critical in this analysis. The capability of TEM in UBM microstructure studies is demonstrated.