An X-ray absorber layer in the form of single layer of high melting point metal such as Ta, W is formed with granular crystal grains on a mask substrate, so that an internal stress of the layer is reduced. A fine pattern is formed from the absorber layer by reactive sputter etching using CBrF.sub.3 gas as an etchant, so that an X-ray absorber pattern is formed on the mask substrate. The X-ray lithography mask thus fabricated has a fine pattern such as submicron pattern with a high degree of pattern contrast and a high dimensional accuracy.