A simple method for manufacturing silicon masks for deep X-ray lithography, conducted with the application of exposure radiation of the spectral range (0.5–7 Å), is described. This method is based on planar silicon technology, which is widely used in the production of semiconductor devices. A significant difference between this method and previously known analogues is that it does not apply the creation of a stop layer by doping during formation of the support membrane of the mask. As the initial blank, a standard (100) oriented silicon wafer is used. The silicon support membrane of the mask is formed in the final stage of its manufacture by plasma-chemical etching of the rear-side of the wafer to a predetermined depth. The thus obtained X-ray masks on a silicon wafer are characterized by relative ease of manufacture, radiation and chemical resistance, geometric stability, and relatively high levels of mechanical strength and X-ray transparency of the support membrane, depending on its thickness, which can be manufactured with good accuracy and within a fairly wide range of ~2.5–50 μm, depending on the purpose of the mask.