Z-pinch plasma radiation source for X-ray lithography

Abstract

Progress in the production of integrated circuits which are the main component of different microelectronic devices in many respects depends on advances in lithography. A critical parameter that determines performance of microelectronic devices is a minimum feature size of an integrated circuit. At present lithography uses krypton-fluorine lasers with the 248-nm wavelength as a radiation source. It allows achieving minimum feature size of 180 nm. Further reduction is limited by lack of lasers with shorter wavelength and optically transparent materials. For the spectral range 3-30 nm, multilayer mirrors are now available, which can be used in lithography to produce elements with minimum feature size determined by wavelength of a radiation source in this spectral range. A plasma radiation source based on a gas-puff Z-pinch is suitable for such application. Nowadays there are installations of different energy scale, which are able to produce from 0.5 J to 3-4 MJ in single discharge regime and 0.02 J/pulse in repetitive regime (150 Hz) in the spectral range of 0.1-30 nm. Our gas-puff Z-pinch installation IMRI-3 (250 kA) provides radiation yield up to 200 J in the spectral range 3-30 nm. A new repetitive installation was designed with IMRI-3 as a prototype. The use of different working gases allows optimization of radiation yield for a certain spectral line in the operation spectral range of multilayer mirrors.