The fabrication development of DPP source collector for EUVL in Harbin Institute of Technology

This paper introduces a new processing technique for discharge produced plasma source collector of EUV Lithography in Harbin Institute of Technology. The main idea is using the ultra-precision diamond lathe to process the inner and outer surfaces of the mirror. The mirror substratum's material is aluminum alloy (LY-12). In rough turning, we also do the stabilizing treatment 7 or 8 times to make the aluminum alloy stable enough for mirror substratum as the mirrors' thickness are only 2~3mm. The following process is finish turning after which the collector mirror will be coated with nickel-phosphorus alloys of the thickness about 40~50μm. Next, do the finish turning process again to obtain the final surface shape of the mirror. The polishing method is hand-polishing. It's proved that the processing technique has the advantages of short processing cycle, low processing cost, high surface precision and so on in practice.