Effect of Processing on Environmental Degradation of Brazed and Plated Kovar Leads

摘要

The occurrence of both pitting corrosion and environmental cracking in Kovar leads has compromised the reliability of lead frame packages. Five differently processed groups of lead frames were subjected to an environmental test and metallographically examined to determine what process factors influence susceptibility to environmental degradation. Increasing the thickness and quality of gold plating on the Kovar leads was found to decrease degradation. A nickel plating of the Kovar lead before brazing to the lead frame was identified as being deleterious due to lead wetting by the braze material. (ERA citation 07:044183)