High-lead die attach printing paste for power package assembly

With the development of new technology, more and more customers requires high lead printing paste instead of dispensing paste. The driving force of this conversion is printing process has much higher production efficiency than dispensing process. For high lead printing paste, it has a much longer time to expose to air than dispensing paste during application process. The long time exposure to air would cause new problem to paste and affect the paste performance. This paper aims to investigate the "hard skinning" issue with high lead alloy printing paste, the effect of metal content on wetting, the effect of alloy composition on wetting, the impact of alloy composition on paste stencil life. All these studied variables are significant in having a great impact on the paste performance in die attach process.