title: Radiation hardness of molybdenum silicon multilayers designed for use in a soft-x-ray projection lithography system.
abstract: A molybdenum silicon multilayer is irradiated with 13.4-nm radiation to investigate changes in multilayer performance under simulated soft-x-ray projection lithography (SXPL) conditions. The wiggler-undulator at the Berlin electron storage ring BESSY is used as a quasi-monochromatic source of calculable spectral radiant intensity and is configured to simulate an incident SXPL x-ray spectrum. The test multilayer receives a radiant exposure of 240 J/mm(2) in an exposure lasting 8.9 h. The corresponding average incident power density is 7.5 mW/mm(2). The absorbed dose of 7.8 × 10(10) J/kg (7.8 × 10(12) rad) is equivalent to 1.2 times the dose that would be absorbed by a multilayer coating on the first imaging optic in a hypothetical SXPL system during 1 year of operation. Surface temperature increases do not exceed 2 °C during the exposure. Normal-incidence reflectance measurements at λ(0) = 13.4 nm performed before radiation exposure are in agreement with measurements performed after the exposure, indicating that no sign icant damage had occurred.
authors.forename: D P
authors.initials: DP
authors.lastname: Gaines
authors.forename: R C
authors.initials: RC
authors.lastname: Spitzer
authors.forename: N M
authors.initials: NM
authors.lastname: Ceglio
authors.forename: M
authors.initials: M
authors.lastname: Krumrey
authors.forename: G
authors.initials: G
authors.lastname: Ulm