Abstract: A technique for making a high resolution X-ray mask with high aspect ratio absorber patterns sufficient for use in X-ray lithography wherein a thin resist layer is used to provide a low contrast mask, and then an X-ray exposure is used to increase the aspect ratio of the absorber to increase the contrast of the mask. The mask is first patterned with an e-beam resist exposure and development step, and the plating of the base material is activated by a reactive ion etch followed by electroplating. The resist is removed and the mask is coated with a negative acting X-ray resist. The back of the mask is exposed to X-rays wherein the existing absorber acts as an X-ray mask to expose the desired areas of the resist. The resist is removed after development, reactive ion etching and electroplating resulting in a mask with high contrast.