Estimation of Mask Placement Error Caused by Multilayer Stress Profile

概要

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In order to clarify the influence of multilayer stress distribution on the pattern placement accuracy of an extreme ultraviolet (EUV) mask, the in-plane displacement (IPD) of the mask was calculated using a simulation model based on two-dimensional plane stress theory. In order to deal with multilayer stress distribution, average stress, fluctuation stress and periodic length were defined as parameters. The parameters, which have a significant influence on the mask IPD, are the fluctuation stress and the periodic length. It was found that the average stress of a multilayer film did not affect the mask IPD. An EUV mask with pattern density of 100% makes IPD small by decreasing the fluctuation stress. For EUV masks of 150 mm and 100 mm squares, the periodic lengths that generate the peak IPD in the mask are 200 mm and 150 mm, respectively. In order to improve EUV mask pattern placement accuracy, it is important to achieve the development of uniform multilayer stress distribution.
Publication Office, Japanese Journal of Applied Physics, Faculty of Science, University of Tokyoの論文
2003-01-15