Palladium pre-plated copper leadframe for DRAM LOC packages

Though palladium (Pd) pre-plated copper (Cu) leadframe has been used in the packaging of logic and linear devices since its introduction in 1989, it still has not found its place in DRAM devices due to the lack of market acceptance and the difficulties copper leadframe poses to TSOP LOC packages. However, the requirements for improved heat dissipation of the new generation DRAM products have driven the need to explore the use of copper leadframe as a replacement for alloy 42 material. Copper with a thermal conductivity of 10x greater than alloy 42 has the potential to be an effective and cost effective method of enhancing thermal dissipation. This paper summarizes the findings of the development of Pd-Cu leadframe technology for DRAM LOC type TSOP. These include package and solder joint reliability, solderability, warpage control and impact on thermal impedance