Download presentations (PDFs)
Part 1: Introduction, Assembly Process Development
Part 2: Rework Process Development, Process Robustness Assessment/Reliability, Key Observations/Conclusions, Q&A
NOTE: the Lead-Free Assembly & Rework Project's final report is available to iNEMI members on CD. If you would like to receive a copy, please contact Dee-Dee Taylor (+1 703-834-2087; email@example.com).
A team of iNEMI companies collaborated for three years to develop Pb-free assembly and rework processes for double-sided, 14-layer, printed circuit boards (PCBs) in two thicknesses (0.093" and 0.135") with electrolytic NiAu and Immersion Ag surface finishes. This work followed the initial SMT manufacturing feasibility effort carried out by the first iNEMI Pb-free development team (1999-2002).
All SMT assembly, PTH wave assembly and component rework processes were carried out on production equipment. Various test vehicles including the reliability test board were used in a multiphase development project to develop Pb-free assembly and rework parameters and temperature profiles prior to a 100-board process technology verification build. Following the double-sided SMT and wave assembly build, half of the printed circuit assemblies were passed through a series of representative component rework protocols. Each build group was then subjected to a series of mechanical and thermal reliability stress tests, including 5700 cycles of 0°C to 100°C, followed by failure analysis.
A special test board was designed utilizing a high-temperature laminate designed for Pb-free soldering. Approximately 30% of the assemblies were SnPb control samples. This webinar will present the Pb-free SMT assembly and rework process developed using the iNEMI Sn3.9Ag0.6Cu solder, and results of the reliability stress tests. The rework of large, thick PCBs with Pb-free solder poses a significant challenge to the industry. The lessons learned and recommendations for future work will be discussed.