Observation of extreme ultraviolet light emission from an expanding plasma jet with multiply charged argon or xenon ions

Abstract

We report the first direct demonstration of possibility to generate the extreme ultraviolet (EUV) radiation with a freely expanding jet of dense plasma with multiply-charged ions supported by high-power microwaves. The detected emission power is about 20 W at 18-50 nm for argon and xenon and 0.3 W at 13-17 nm for xenon. The discharge with a peak electron density up to 3 × 10 16 cm −3 and a characteristic size of 150 µm is supported by a focused radiation of a recently developed gyrotron with unique characteristics, 250 kW output power at 250 GHz, operating in a relatively long (50 µs) pulse mode. Up-scaling of these experimental results gives grounds for development of a point-like kilowatt-level EUV source for a high-resolution lithography able to fulfill requirements of the microelectronics industry.

On Stationary Flow of Dense Plasma under Localized Energy Deposition

“…As a rule, ratio (23) for subterahertz discharges is a number that is much greater than unity. For a pressure of p ~ 0.1 atm, a linear size of the discharge of l 100 μm, particle fluxes Gl 2 ~ 10 18 s -1 , and total radiation power Ql 3 ~ 100 W, which are characteristic of a discharge in a xenon flow from experiments [5], the assessment of the R q parameter by Eq. ( 23) with thermal conductivity coefficient (T) = 0 T 5/2 corresponding to a fully ionized plasma with parameter 0 3.5 × 10 31 cm -3 eV -3/2 g -1 s calculated according to max / I GT [25], a xenon ion mass of g, and from Eq.…”

“…Nowadays, the applications related to the use of a discharge supported by the radiation of a gyrotron in a gas flow are being actively developed [1][2][3][4][5]. Modern devices are capable of operating in the subterahertz frequency range and have an average power at the level of several hundreds of kilowatts [6], which makes it possible to maintain plasma with densities up to 10 16 cm -3 and to reach average electron energies of about 100 eV [7].…”

Terahertz gas discharge: current progress and possible applications

“…At present, mainly the breakdown thresholds in heavy noble gases have been studied. The discharge in these gases is of interest from the point of view of an intense source of vacuum and extreme ultraviolet (EUV) radiation [7,29,30] (see Section 4).…”

Особенности Пробоя Тяжелых Инертных Газов В Сфокусированном Пучке Излучения Новосибирского Лазера На Свободных Электронах

“…Плотная плазма THz-разряда может использоваться как интенсивный источник ультрафиолетового излучения вплоть до экстремального УФ (ЭУФ) [6]. Плотность плазмы, характерная для THz-разряда, лежит в пределах 10 16 −3 • 10 17 cm −3 .…”