Patent Number: 
Section: claims

1. An x-ray mask tool, comprising: a silicon substrate having a thickness, a top surface, and a bottom surfaces substantially parallel to said top surface, said silicon substrate having at least one pattern etched into said top surface, said at least one pattern extending to a depth of at least 10 microns into said thickness and comprising a plurality of etched channels having substantially parallel sides, said etched channels filled with a metal deposit to provide a plurality of metal structures embedded into said silicon substrate extending to said depth and flush with said top surface, said metal structures comprising features having lateral dimensions of less than 1 micron. 2. The x-ray mask tool of  claim 1 , wherein said metal deposit is any metal capable of attenuating x-ray radiation to an energy of below about 0.1 KeV in a distance of less than about 100 microns. claim 1 3. The x-ray mask tool of  claim 1 , wherein said metal deposit is a metal selected from the group consisting of the Transition series of metals listed in New IUPAC Group Numbers 4-12 of the Period Table of elements, aluminum, tin, and alloys thereof. claim 1 4. The x-ray mask tool of  claim 1 , wherein said metal deposit consists essentially of gold. claim 1 5. The x-ray mask tool of  claim 3 , wherein said metal deposit comprises a thin vapor deposited first metal layer. claim 3 6. The x-ray mask tool of  claim 5 , wherein said vapor deposited first metal layer comprises a first layer of chromium. claim 5 7. The x-ray mask tool of  claim 5 , wherein said metal deposit is deposited by electroplating. claim 5 8. The x-ray mask tool of  claim 5 , wherein said metal deposit is deposited by electroless deposition. claim 5 9. The x-ray mask tool of  claim 5 , wherein said metal deposit is deposited by thermal or particle vapor deposition. claim 5 10. The x-ray mask tool of  claim 5 , wherein said metal deposit is deposited by sputter deposition. claim 5 11. The x-ray mask tool of  claim 5 , wherein said metal deposit is deposited by molecular beam epitaxy. claim 5 12. The x-ray mask tool of  claim 1 , wherein said silicon substrate is thinned from said bottom surface to a thickness of less than 100 microns across a zone encompassing said pattern. claim 1