In this article, the effects of tungsten and resist thickness and exposure energy on tungsten x-ray masks have been investigated making use of both experimental and theoretical data. It was found that proximity effects in the patterned resist can be reduced by an appropriate choice of resist and absorber thickness as well as increased electron energy. The control of linewidths for isolated lines, clustered lines, and isolated spaces is sufficient for 0.25 mum design rules without proximity correction and with good process latitude. In addition, it was found that this process has resolution down to 0.1 mum.