A holistic scanner matching solution for productivity enhancement in a Giga fab

In this work, we propose a new technique for comprehensive scanner matching to fundamentally improve scanner productivity in a Giga fab. The proposal covers matching solutions for both CD and overlay fingerprints among scanners. CD matching strategy has three main components. The first part is to apply model-based scanner tuning for scanner optics matching. The second part is to apply hotplate-tuning mechanism for within-wafer CD uniformity improvement. The third part is to achieve focal plane control with a novel focus metrology method. Overlay control and matching are achieved with periodic inter-field and intra-field high order process correction with respect to the chosen baseline of overlay fingerprint for each scanner. Together with the existent inline automatic process control infrastructure, which suppresses the residual process-induced CD and overlay variations, a holistic scanner matching solution can be implemented in the fab for productivity and yield enhancements. Convincing proof data is provided in this paper to demonstrate the feasibility of our approach.