A Monte Carlo simulation has been performed for photoelectrons and Auger electrons generated in Si or Ge doped polymethyl methacrylate (PMMA) resist (Si5xC5(1−x)H8O2or Ge5xC5(1−x)H8O2) films for the enhancement of dry etching resistance under MoLα x‐ray exposure. It is found that the addition of such heavy elements, especially Ge, into the resist is very effective for reducing the spatial spreading of energy absorption. Calculations for line and space patterns with an equal 100 nm width show that the interproximity effect between the patterns decreases significantly with an increasing content of heavy atoms doped. It is also shown that about the same resolution as obtained for a pure PMMA resist with an AlKα x ray (1.5 keV) can be achieved with a MoLα x ray (2.3 keV) by adding Ge atoms with a content ofx=0.1–0.2 into the resist.