Adaptation of brass core lead frame material in IC packaging

In today´s lead frame IC packages, the cost of lead frames account for one of the largest portion of material costs. Etched lead frames can cost 50% of the total package cost where as stamped frames can cost around 30%. With the increasing price trend of raw copper material in recent years, fueled by increasing demand on the use of copper (e.g. as an Au bonding wire replacement) this will inevitably impact the cost of high copper purity core lead frame. It will add a significant cost to the total package cost. Therefore an alternative, cheaper leadframe material is very much needed to keep the total packaging cost down. This paper will report the investigation of the use of brass core material as an alternative replacement to high purity copper alloy lead frame. General cost advantages, technical challenges and assembly feasibility on the use of brass core lead frame material are assessed and discussed. Reliability assessment will only be done in our next phase of investigation.