Single wafer cleaning lessons in advanced node gate module development

With single wafer cleaning becoming a mature part of advanced semiconductor manufacturing, it seemed appropriate to reflect on a period of rapid and dramatic change within the gate module. Specifically, there are 6 key learnings that have enabled our team to take embedded contamination from top of the yield pareto to a more baseline level of defectivity. Those key learnings were: 1) Particle removal efficiency is critical. 2) DI Prewet improves pattern fidelity. 3) S/P ratio drives dual gate chemical oxide growth. 4) Hydrophobic dewetting can occur. 5) Predispense sequences are critical. 6) Concentration differences between batch and single wafer tooling can drive significant effects.