Engineered interfaces for enhanced oxidation/corrosion resistance of ultra thin pre-plated leadframes

Optimizing the elelctroplating condition, the thickness of a Pd layer in the Au/Pd/Ni/Cu pre-plated leadframe (PPF) is reduced to 8 -10 nm. Introducing a ~10 nm thick dense (Cu,Ni)₃Sn intermetallic compound (IMC) layer in the PPF drastically reduces Cu out-diffusion and hence improves significantly the protection of the leadframes against oxidation and corrosion attack. The microstructural characterization results indicate that the success in the development of ultra-thin PPFs with a Ni layer thickness less than 200 nm is attributed to coherent/semi-coherent interfaces between the layers and the Sn-based IMC.