From an image formation point of view, the design of x‐ray masks has been optimized for realistic exposure systems using synchrotron radiation. The analysis has then been carried forward to study the effect of environmental factors such as vibrations. We conclude that the ideal x‐ray mask is based on thin absorbers (0.3–0.4 μm) for Au and W, that the existence of a sidewall slope improves the exposure latitude, and that vibrations (amplitude less than 1/2 critical dimension) do not represent a source of concern. All in all, the x‐ray lithography mask emerges with more relaxed specifications and with a simpler manufacturing process.