High-NA EUV lithography exposure tool: advantages and program progress

While EUV systems equipped with a 0.33 Numerical Aperture (NA) lens are entering high volume manufacturing, ASML and ZEISS are in parallel ramping up their activities on an EUV exposure tool with an NA of 0.55. The intent of this high-NA scanner, targeting a resolution of 8nm, is to extend Moore's law throughout the next decade. The high-NA optical system, together with the developments in mask and resist, provides an increased contrast, key to control stochastic contributions to EPE and the rate of printing defects. A novel lens design, capable of providing the required NA, has been identified; this lens will be paired with new, faster stages and more accurate sensors enabling the tight focus and overlay control needed for future process nodes. Impact on system architecture and proposed solutions are described in this paper. In addition, we give a status update on the developments at ZEISS and ASML.