Extreme ultraviolet (EUV) radiation and plasma diagnostics of the dense plasma focus for EUV lithography (EUVL)

Summary form only given. We have generated the Ar plasma in the diode chamber based on the established coaxial electrode type and investigated EUV radiation and the emitted visible light for emission spectroscopy. The optical emission spectrum data have been obtained for the focused plasma in the cylindrical diode chamber under the input voltage of 4.5 kV. We observed the two emission lines and their spectral broadenings for Ar I; 404.42 nm and Ar II; 487.99 nm. The electron density has been measured by the Stark broadening from assumption of local thermodynamics equilibrium (LTE). The electron temperature can be determined by the relative ratio for the respective electron densities for Ar I and Ar II. The EUV photo-detector (AXUV-100 Zr/C, IRD) with band pass wavelength of 6 ∼ 16 nm has been installed along the side chamber set by the angle of ∼30 degree with respect to diode axis. We observed the emitted EUV light along the side direction of the pinched area of focused plasma.