https://www.spiedigitallibrary.org/...g-using-wavefront-and/10.1117/12.3009878.full
This paper ("Improving EUV sub-40nm via single patterning using wavefront and pupil co-optimization") from SPIE this year is the work of an extensive collaboration between Samsung and ASML. It describes Pupil/Mask/Wavefront co-optimization for sub-40nm pitch applications. As stated in the abstract, EUV stochastic defects induced by EUV photon shot noise are known to strongly correlate to image contrast. The paper focuses on improving contrast by reducing image fading from mask 3D effects. Ultimately, "alternative optimization strategies, focusing on dose reduction, are being studied to further enhance the patterning performance of low-n masks by means of Pupil/Mask/Wavefront co-optimization."
But the real loud statement is actually what was not mentioned: high-NA. Given that there was a close collaboration between Samsung and ASML, it is quite strange to not even get a roadmap reference to High-NA. Not even a statement like "since a High-NA system will not be available soon enough, we seek methods using current 0.33 NA systems." ASML apparently did not push Samsung very hard on High-NA.
This paper ("Improving EUV sub-40nm via single patterning using wavefront and pupil co-optimization") from SPIE this year is the work of an extensive collaboration between Samsung and ASML. It describes Pupil/Mask/Wavefront co-optimization for sub-40nm pitch applications. As stated in the abstract, EUV stochastic defects induced by EUV photon shot noise are known to strongly correlate to image contrast. The paper focuses on improving contrast by reducing image fading from mask 3D effects. Ultimately, "alternative optimization strategies, focusing on dose reduction, are being studied to further enhance the patterning performance of low-n masks by means of Pupil/Mask/Wavefront co-optimization."
But the real loud statement is actually what was not mentioned: high-NA. Given that there was a close collaboration between Samsung and ASML, it is quite strange to not even get a roadmap reference to High-NA. Not even a statement like "since a High-NA system will not be available soon enough, we seek methods using current 0.33 NA systems." ASML apparently did not push Samsung very hard on High-NA.
