In x-ray lithography, the energy deposition mechanism of secondary electrons generated in the resist and Si substrate is investigated. By reducing resist thickness, the secondary electron blur is reduced because secondary electrons with high energy exit the resist before depositing energy in the lateral direction. Resolution is improved using a thin Cl-containing resist, especially in wavelengths shorter than the K-shell absorption edge of Cl atoms. The secondary electron blur in the wavelength region from 2.5 to 4.0 Angstrom decreases using a 40-nm-thick Cl-containing resist with a bottom layer. By using an x ray in this wavelength region, the 35 nm line-and-space pattern can be resolved at a gap of 10 mum. A higher quality resist pattern can be obtained by increasing the Cl contents in the resist. (C) 2004 American Vacuum Society.