Yu B Kiryukhin

High-power gas-discharge EUV source

The results from studies aimed at creating a high-power high-repetition-rate gas-discharge EUV source based on xenon Z-pinch are presented. In a liquid-cooled EUV source prototype, an average output power of 10 W for the burst mode (∼1 s) and 5 W for continuous operation, emitted into a solid angle of 0.25 sr and 2% bandwidth around 13.5 nm is attained at a repetition rate of ∼1 kHz. Operating wavelength of the source corresponds to XeXI 13.5-nm ion emission band. It is experimentally shown that the size of the emitting hot plasma can be decreased to ∼2 mm without loss in the average output power. The radiation characteristics were determined by using standard techniques and calibrated metrology tools, which allowed a comparison of the absolute values of the measured parameters with the available data on other EUV sources developed for the next-generation lithography with a resolution of ∼50 nm. The attained level of an average EUV power of 10 W at λ=13.5 nm into the 0.25-sr solid angle and 2% bandwidth is one of the highest at the moment.

Creation and investigation of powerful EUV sources (λ ≈ 13.5 nm)

Results are presented from experimental studies of repetitively pulsed EUV (λ = 13.5 ± 0.135 nm) sources based on a laser-initiated discharge in tin vapor between rotating disk electrodes. Radiative characteristics of two sources with different systems of tin supply onto the electrode surface and different types of power supply have been compared. A number of new effects have been revealed at pulse repetition rates as high as ∼4000 Hz. A mean radiation power of 520 W into the 2π solid angle has been achieved in the spectral band 13.5 ± 0.135 nm at a deposited electrical power of 24 kW.

Intense high-repetition-rate excimer lasers and applications

Building of high average output power excimer lasers requires the solution of several complex problems. The main challenge is the creation of a uniform discharge which can be easily reproduced even at high pulse repetition rates. Some approaches to solving this problem are discussed. They resulted in creation of lasers with aperture of 4 sq cm operating at 1 kHz producing the output of 420 W at 308 nm. A large-aperture XeCl laser can produce 10 J per pulse at 50 Hz.