Extreme-ultraviolet light source development to enable pre-production mask inspection

摘要

As extreme-ultraviolet (EUV) lithography moves into pre-production, the requirement for commercially available mask metrology tools becomes more urgent. A key to developing a successful tool is a reliable, high-brightness EUV light source. The Energetiq EQ-10 is a commercially available EUV light source, with an installed base of over 15 sources in the field. The source relies on an electrodeless Z-pinch™ to produce greater than 10 Watts/2π of 13.5 nm 2% bandwidth light. In order to meet brightness and stability requirements of mask metrology tools, we have investigated modifications to the original design of the EQ-10. The result of these modifications has roughly doubled the source output power, and has achieved brightness greater than 8 Watts/mm2/sr, without sacrificing the spatial and pulse-to-pulse stability of the original design. This level of performance is sufficient for initial mask blank and imaging inspection tools.