Researchers from National Yang Ming Chiao Tung University and TSMC have published a technical paper proposing a new material approach for extreme ultraviolet lithography. The study, titled “High contrast EUV imaging enabled by topological quasi phase-only masks,” introduces molybdenum-based quasi phase-only masks as an alternative to conventional tantalum absorbers. The authors describe this as a paradigm shift in EUV phase-shifting mask technology, aiming to improve image quality through high reflectivity and minimal absorption.
35% contrast gain in simulations
. The study also reports a fivefold increase in the common focus window and a 92% reduction in peak telecentricity error. These improvements are claimed to enable 12.5-nm half-pitch resolution for 0.33 numerical aperture EUV systems using monopole illumination.
Optics Express publication details
The work was authored by Po-Hsun Fang, Pokai Chang, Chaowei Huang, Lee-Feng Chen, Yen-Liang Chen, and Peichen Yu, and was published in Optics Express in August 2026. The paper spans pages 30091 to 30105 of volume 34. This research contributes to the broader ecosystem of EUV lithography development, where mask technology is a critical component for achieving higher resolution and yield in advanced semiconductor manufacturing.
Implications for mask suppliers
This development is significant for the EUV lithography supply chain, particularly for mask manufacturers and foundries planning next-generation nodes. By proposing molybdenum as a superior absorber material, the study addresses key limitations of current tantalum-based masks, such as lower contrast and larger telecentricity errors. If validated in production, this could lead to improved process windows and higher yields for 0.33 NA EUV systems, which are central to current leading-edge logic and memory production.
Bridge to high-NA EUV roadmap
The collaboration between an academic institution and a major foundry like TSMC suggests a strong potential for industrial adoption, as it bridges theoretical simulation with practical manufacturing needs. This is relevant to equipment planners and mask suppliers who must consider material changes in their roadmap to support higher resolution requirements. The industry is currently focused on scaling high-NA EUV, with initiatives like the 12-inch mask collaboration involving NY Creates, ASML, and TSMC aiming to support larger reticles for sub-1nm nodes.
Yield and process window benefits
While the results are based on electromagnetic simulations and have not yet been independently verified in a production environment, the potential impact on yield and process window is substantial. For storage and semiconductor readers, this represents a foundational improvement in the lithography stack that underpins the production of high-density NAND, DRAM, and logic chips. As the industry pushes toward higher densities and smaller nodes, optimizing every aspect of the imaging chain, including mask materials, becomes critical for cost and performance.