Lasing efficiency of krypton ions in the (8 – 14)-nm band upon pulsed laser excitation

Abstract

The emission spectra of krypton plasma in the range of 8 – 14 nm upon excitation of a pulsed gas jet by 1.06-mm Nd : YAG laser radiation with a pulse energy of 0.85 J, pulse duration of 5.2 ns, and repetition rate of 10 Hz are investigated. The krypton emission spectrum is a wide (8 – 14 nm) band, peaking at 10.3 nm, which is formed by a series of much narrower lines. The observed lines are identified, and the fraction of laser pulse energy converted into the (8 – 14)-nm emission band and emitted into half-space (2π sr) is determined. The maximum conversion efficiency is found to be 21 %. The expected throughputs of lithographic systems with sources based on Sn, Xe, and Kr ions for different wavelengths, corresponding to the emission peaks of ions of these materials, are compared.

Ru/Sr multilayer mirrors for the spectral range 9-12 nm

“…At this stage of technology development, the possibility of switching to lithography with a wavelength shorter than 13.5 nm [3,4] is being actively discussed. In the range of 10−11 nm lie the maxima of krypton and xenon plasma radiation [5,6].…”

Многослойные зеркала Ru/Sr для спектрального диапазона 9-12 nm

“…На данном этапе развития технологии активно обсуждается возможность перехода к литографии с длиной волны короче 13.5 nm [3,4]. В диапазоне 10−11 nm лежат максимумы излучения криптоновой и ксеноновой плазмы [5,6]. Продвижение технологии проекционной литографии в этот диапазон сдерживается отсутствием достаточных (порядка 60%) коэффициентов отражения МЗ.…”