Articles you may be interested inResidual-type mask defect printability for extreme ultraviolet lithography J. Vac. Sci. Technol. B 30, 06F501 (2012); 10.1116/1.4756934 Sub-30 -nm patterning on quartz for imprint lithography templates Appl. Phys. Lett. 93, 083123 (2008); 10.1063/1.2963982Simple fabrication of UV nanoimprint templates using critical energy electron beam lithography Masks of any next generation lithography (NGL), such as imprint lithography, must eventually achieve and maintain the very low defect counts of current production masks. This requires typically fewer than 10 or even no defects over the entire field. We describe an inspection methodology and how it can be applied to the imprint template. Special test patterns etched onto the template enable both a die to die comparison, to find nuisance defects, and also calibration of sensitivity to different types of preprogrammed defects. A state of the art deep ultraviolet photomask inspection system (KLA-Tencor model 526) can detect these rare events with about 70 nm threshold for imprint masks with reflection mode contrast. Initial scans are made at various stages of the imprint process: the newly processed mask, after dicing, and after several imprints. The scans show mostly isolated point defects at a density of ϳ10-100 per mm 2 . This is an encouraging start for a new NGL, and reductions are expected from better processes, equipment, and handling. In the future viable mask inspection at the 45-22 nm node will be very demanding for these 1ϫ masks and will require sensitivities approaching 10-20 nm defect size. To this end, special masks suitable for electron (e)-beam inspection are being made and show good contrast and immunity to e-beam charging.
The design of permanent magnets for use in the Fermilab Main Injector "Recycler" ring is described. The magnets are a hybrid design with the field shape determined from accurately machined pole tips and the field driven by strontium ferrite blocks. The choice of magnetic material is discussed. A temperature compensation scheme has been demonstrated which uses a low Curie-temperature alloy to null out the intrinsic temperature coefficient to the ferrite. 1.2m prototype magnets have been constructed which achieve the design goal of dB/B < 10-4 over an aperture of 3.5"(h) x 2"(v).
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