Application of a high-brightness electrodeless Z-pinch EUV source for metrology, inspection, and resist development.

Traditional Z-Pinch discharge plasma sources designed for EUV applications use electrodes to conduct the high current pulse into the plasma. The contact of these electrodes with the high temperature plasma required for EUV production can cause issues of electrode erosion, electrode spitting and even melting. These can be sources of contaminating debris for any optical system connected to the source. We will present a novel approach to the Z-pinch discharge plasma where the current pulse is induced into the discharge, rather than conducted. The inductive coupling creates magnetic fields which position the resulting electrodeless z-pinch plasma away from the source walls, thereby allowing relatively straightforward approaches to source cooling. We will show results from a commercially available electrodeless z-pinch EUV source that delivers 10Watts at 13.5nm (+/- 1% bandwidth) into 2 pi steradians. using xenon as the EUV emitting gas. Source size measurements and the ability to tailor the size to specific applications will be presented. In particular we will report on the optimization of the source for high brightness, for applications such as EUV metrology, microscopy and defect inspection of EUV masks and mask blanks, and the optimization of the source for power output for applications such as resist exposure and resist out-gassing studies. In imagine, applications, the illumination optics are often able to reject light except from the immediate region of the pinch. This characteristic has consequences for out-of-band light measurements. We will present out-of-band measurements of light from a highly collimated view of the pinch.