Contamination on Extreme Ultraviolet Optics Induced by Xenon‐Based Electrodeless Z‐Pinch Plasma

One of the new challenges arising with the introduction of extreme ultraviolet (EUV) lithography is contamination caused by debris. Xe‐based electrodeless discharge produced plasma (DPP) sources are considered advantageous because they have no electrode and use noble gases, which are not thought to produce debris. This makes them preferred for certain applications, such as inspection and evaluation tools. However, Xe DPP sources also has a potential contamination risk due to sputtering of materials around the pinch region, an issue that has not been investigated enough. In this article, the contamination of EUV optical components by the Xe‐based Z‐pinch plasma source is analyzed. Residual gas analyzer measurements confirm that the insulating insert is sputtered during pinch discharge, and the resulting Si and C diffuse with the discharge gas. Energy dispersive spectroscopy and X‐ray photoelectron spectroscopy analyses verify the deposition of C on Si wafer and Al foil substrates. To mitigate this, hydrogen buffer gas is introduced, significantly reducing the deposition. As the buffer gas pressure increases, carbon deposition decreases by up to 44%. These results underscore the effectiveness of hydrogen buffer gas in mitigating contamination in Xe‐based EUV sources.