Debris mitigation of a Xe discharge-produced plasma source combined gas jet and Halbach cylinder

Abstract

High-energy ions and metal debris generated by extreme ultraviolet (EUV) light sources pose a severe threat to collector optics. This study demonstrates a hybrid mitigation strategy that combines a helium buffer gas jet with a segmented Halbach cylinder to suppress debris from a discharge-produced plasma source. A semi-analytical model incorporating finite-length effects was developed to optimize the magnetic topology, achieving a central field strength exceeding 0.85 T for magnetic mitigation. Scanning electron microscopy and atomic force microscopy reveal a pristine witness surface with a 36% reduction in roughness compared to the non-magnetic case. In situ quartz crystal microbalance measurements demonstrate that the magnetic field alone reduces debris mass deposition by approximately 69%. Furthermore, unlike heavier buffer gases, the helium jet stabilizes mitigation performance with minimal in-band EUV absorption. These results establish the combined jet–magnetic scheme as a compact, high-efficiency solution for next-generation lithography sources.