Investigation of MURA performance of the multi-beam mask writer 100 Flex, including intra-writing field and beyond

Unevenness caused by periodic fluctuations due to wave effects on imager devices is referred to as "MURA," a Japanese term meaning unevenness. Periodic CD and registration variations of photomasks used in the manufacturing of these imager devices are influential factors for MURA effects. The mask writers used for exposing such photomasks are the primary source of these variations. Multi-beam mask writers (MBMWs) tend to have less impact on MURA-related variations compared to variable shaped beam writers (VSBs) due to their working principle. Previously, MURA periodic variations were mainly investigated for effects related to writing field variation. In principle, variations beyond the writing field scale are also possible, and their contribution to the overall error budget should be investigated further. This paper reports on MURA-related investigations across multiple mask scales, including intra-writing field and beyond writing field. By using local registration measurements on customized test design, we were able to distinguish multiple influence factors and their contributions to the overall error budget. Using this approach, MURA-related signatures on the MBMW 100 Flex could be minimized.