Optimizing photoresist linewidth roughness in ion beam shaping: A systematic study of stage angular configuration

Linewidth roughness (LWR) control is a pivotal factor in advancing semiconductor device performance and yield at nanoscale technology nodes. As a critical post-lithography corrective technique, ion beam shaping (IBS) offers promising potential; however, a comprehensive understanding of the precise mechanism by which the process stage angles influence LWR optimization remains imperative for its effective industrial application. This study provides a systematic investigation into the individual and combined effects of stage rotation and tilt angles during IBS on photoresist LWR. The ion beam shaping mechanism was uncovered by evaluating LWR variations—quantified by 3σ and power spectral density—under isolated angular adjustments. A key finding is that while individual angle adjustments (tilt or rotation) can suppress mid-to-high frequency roughness, their synergistic combination achieves comprehensive smoothing across the entire frequency spectrum. Furthermore, through a systematic analysis of data from coordinated rotation and tilt adjustments, along with optimization of the shaping time for various angular configurations, this work establishes a process window for highly efficient photoresist LWR reduction. Crucially, this optimization is achieved under low beam energy conditions, highlighting a strategy to mitigate the inherent trade-off with critical dimension loss. It thereby provides both theoretical insights and experimental support for the practical application of IBS technology in LWR control with minimized pattern fidelity degradation.