AIMS EUV evolution towards high NA: challenge definition and solutions implementation

The road towards the next technology leap in EUV lithography is set. ASML and ZEISS have designed and started manufacturing the next generation EUV exposure tool. With a wafer side NA of 0.55, the High NA scanner system will support the further pattern node scaling roadmap by improving image contrast and therewith reduce LCDU and defect print rate on product wafer. As for all major steps in the lithography evolution, the whole infrastructure will develop further in order to support this next quantum leap in EUV technology, with the EUV photomask technologies and metrology tools representing an essential piece of the mosaic. The AIMS® EUV system represents a unique piece of the EUV mask infrastructure for the qualification of the mask printing performance in the aerial image. The AIMS® aerial image is by design targeted to match the scanner aerial image, as the tool is engineered to emulate all imaging relevant scanner properties, e.g., mask side NA, through slit chief-ray characteristics, aberration level, illumination schemes. For the emulation of the High NA scanner, ZEISS developed and started manufacturing an upgrade for the current existing 0.33NA AIMS® EUV platform. The same AIMS® EUV system is therefore capable of imaging 0.33NA isomorphic as well as 0.55NA anamorphic masks, providing the best-in-class performance for both imaging technologies and optimal match to scanner imaging. In this paper the first imaging results of the AIMS® EUV High NA tool are shown together with quantitative analysis of 0.55NA anamorphic imaging properties. The challenges of providing two intrinsically diverse emulation types (0.33NA isomorphic and 0.55 anamorphic) in one single platform are described together with the solutions which were implemented and tested.