Investigation of mask thickness effects and their significance for the 28nm node and beyond

As the feature size in semiconductor manufacturing approaches 28nm and smaller, the impact of mask thickness in photolithography becomes increasingly significant, resulting in Edge Placement Errors (EPE), overlay issues and process window reduction, collectively referred to as 3D effects. The influence of the mask 3D effects come primarily from three factors: absorber topography coupling, mask structure-induced electromagnetic field variations, and lithography-induced shadowing. These effects challenge conventional mask correction strategies and pose a risk to maintaining high yield rates. A new, rule-based modeling approach is proposed to capture and correct 3D effects. The goal is twofold: to ensure that lithography imaging processes maintain high fidelity and to balance the accuracy and performance in full-chip simulations with a good model flexibility. The research presentation progresses through the introduction and priori works of the subject area, near field and other theoretical analysis, then the proposal about a new fast M3D correction method that brings benefits to mitigate a few challenges in existing simulation methods. Finally, an application test case on 28 node dimensions is provided and conclusions are made thereafter.