A holistic approach to extending resist material viability in extreme ultraviolet lithography

This study compared the performance of chemically amplified resists (CAR) and metal oxide resists (MOR) in line and space (L/S) and contact hole (CH) patterning. CAR showed break defects within a 10% CD margin that could not be mitigated by etch process, in contrast to MOR. However, optimization of resist materials and developer processes extended the defect margin. Improved photoresist materials, optimized underlayers, and assist processes further enhanced resolution and pattern fidelity. In CH patterning, CAR remained the primary resist platform, but poor profiles at ADI were observed. The application of the Gas cluster beam (GCB) process enabled low damage bottom CD enlargement, improving the missing margin by 0.5 nm. Moreover, high NA (0.55 NA) exposure at 32 nm pitch CH patterns provided a 50% sensitivity improvement and a 17% reduction in LCDU compared with low NA (0.33 NA) exposure. These results indicate that the integration of advanced CAR materials with optimized processes and high NA lithography offers a viable path to extend CAR based lithography to sub 30 nm pitch applications.