| 摘要 |
FIELD: physics.SUBSTANCE: invention relates to sources of directed (shaped) soft X-rays or, equivalently, extreme ultraviolet (EUV) radiation with wavelength of 13.5 nm or 6.7 nm, currently used or to be used in the near future in high-resolution projection lithography. Plasma is formed by an external focused injector, after which plasma electrons are heated in a magnetic field in electron cyclotron resonance conditions using high-power microwave radiation in continuous mode. Limited-size plasma is generated using a magnetic field and an opening which limits cross dimensions of the plasma on the axis of symmetry of an X-ray mirror, wherein the working side of the X-ray mirror is insulated from plasma streams, neutral droplets of cathode material and high-energy particles. To realise the method, the disclosed directed EUV source includes an injector 1 for focused feeding of plasma 3 into a magnetic trap 4, at the output of which there is an X-ray mirror 11, the opening 16 on the axis of symmetry of which reduces the cross dimension of the plasma 3 stream. The X-ray mirror 11 is turned by the working side from the plasma injector 1. Behind the focal region 12 of the X-ray mirror there is a plasma trap 15, and the configuration of the magnetic field of the magnetic trap 4, dimensions of the plasma trap 15 and the opening 16 on the axis of the X-ray mirror 11 are selected to ensure insulation of the working side of the X-ray mirror 11 from charged and neutral particle streams. The generator 6 of electromagnetic radiation in the millimetre or sub-millimetre wavelength range for heating plasma 3 electrons is provided with concave mirrors 8 which direct electromagnetic radiation 7 from the injector 1 to the plasma 3 stream in the magnetic trap 4 into the region of electron cyclotron resonance 9.EFFECT: high efficiency and operating life of EUV sources.5 cl, 4 dwg |
