Soft-x-ray multilayer mirrors with laterally varying film thicknesses fabricated using laser-beam-scanning chemical vapor deposition

Publisher Website
Google Scholar
Abstract
The authors have developed a control method of spatial film thickness distribution of multilayer mirrors for soft-x-ray focusing systems using an argon–fluoride (ArF) excimer laser-induced chemical vapor deposition (LCVD). A line-shaped laser beam is unidirectionally scanned over an area of 100×100 mm2. The scanning speed is controlled in response to a film thickness distribution which is required to be obtained. A tungsten–silicon (W/Si) multilayer with laterally varying film thickness is successfully fabricated on the design rule, and soft-x-ray (λ=12.8 nm; not polarized) reflectivities from 37% to 20% are obtained at the grazing angles from 18° to 22° in response to the film thickness distribution. Furthermore, the amount of the soft x rays reflected by the multilayer within 100 mm of the substrate is estimated at about 90% of that in the case of the designed distribution, and the feasibility of LCVD for fabricating multilayer mirrors for high performance soft-x-ray focusing systems has been demonstrated.
Keywords