Extreme ultraviolet emission from Xe clusters excited by high intensity lasers [for lithography]

Summary form only given. The property of EUV generation from Xe clusters irradiated with intense lasers was studied. The irradiation conditions were changed with using various laser systems. The wavelength, the pulse width, and the pump energy were widely changed. Xe cluster jet was generated with a supersonic gas jet. Typically, the average number density was measured to be 5 /spl times/ 10/sup 18/ cm/sup -3/ with the backing pressure of 7 atm. The EUV spectrum was obtained with a transmission grating spectrometer. As a result, the highest conversion efficiency can be obtained with a subpicosecond KrF laser pulse in the low density Xe cluster jet. This EUV source is thought to be a debris free source. Then it is attractive for the application to the EUV lithography. Recently, a subpicosecond KrF laser system of 50 W in average power was developed. If we use this system, 5 W EUV source can be obtained with a debris free condition.