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A detailed analysis is performed to investigate the effects of mask contrast, mask-pattern size error and proximity gap on resolution and exposure dose margin for replicating 0.1-µm-region line-and-space (L&S) patterns using synchrotron radiation lithography. The analysis is performed by comparing Fresnel diffraction simulation and pattern replication experiments. When a conventional-contrast (7) mask is used, designing the pattern size of a Ta mask absorber to be slightly narrower than the specified value is a great advantage for faithful pattern replication of 0.1-µm L&S patterns. A large dose margin is obtained for proximity gaps of 15 µm or less. On the other hand, a low-contrast (2.5) mask has an advantage over the conventional mask in that it allows the use of a larger proximity gap for replicating 0.1-µm L&S patterns. A relatively large margin is obtained by limiting the Ta size error to the range of -0.05 µm to +0.03 µm for proximity gaps smaller than 25 µm, and ±0.02 µm for a 30-µm gap.