Fabrication of Thin-Film Fresnel Optics by Combining Diamond Turning and MEMS Techniques

A novel fabrication process was proposed for manufacturing thin-film metal Fresnel lenses for X-ray applications, which combines MEMS technologies and diamond turning technology. To prevent thin-film lens substrates from deflection during diamond turning, the thin films were prepared on single crystalline silicon wafers by electrolytic plating. After the Fresnel lens structure has been generated on the metal thin films by diamond turning, the backside supporting silicon substrate was selectively removed by reactive ion etching. Experimental results demonstrated that submicron level form accuracy and nanometer level surface roughness could be achieved by the proposed hybrid fabrication process.