Fig. 1. Schematic of multilayered filters (left). The difference between the two kinds of filters (right) is the material of the barrier and capping layers.

Fig. 2. XRR results of (a) the Zr/Si and (b) the Zr/B₄C multilayer films after annealing. The fitting results of the structures are listed in Table 1.

Fig. 3. XPS depth profiles for O, Zr, Si, B, and C near the film surface. (a) Zr, (b) Zr/Si, and (c) Zr/B4C. The dotted lines illustrate the profiles of the as-deposited films, and the solid lines illustrate the profiles of the annealed films.

Fig. 4. Deconvolution of the Zr 3d peak of each film on the interfaces corresponding to the etching time of 75 s (Zr), 480 s (Zr/Si), and 640 s (Zr/B₄C). In particular, (a)–(c) as-deposited films and (d)–(f) after annealing at 300°C for 2 h.

Fig. 5. Transmittance curves of (a) Zr, (b) Zr/Si, and (c) Zr/B₄C filters. The graphs show the comparison between the calculated and measured values of transmittance for different samples. The blue curves are fitted by IMD.

Fig. 6. Filter transmittance curves under 13.5 nm EUV irradiation over 17 h. (a) Zr, (b) Zr/Si, and (c) Zr/B₄C.

Fig. 7. Filter transmittance after irradiation with 5 mW high-energy light.

Fig. 8. Left column: (a)–(c) optical microscope images of the damage produced by irradiation. Middle column: (a1)–(c1) SEM images of the undamaged areas of the filters. Right column: (a2)–(c2) SEM images of the damaged areas of the filters.

Fig. 9. XPS survey spectra for all filters after irradiation. The binding energy ranges between 0 and 700 eV, where only the C 1s and O 1s peaks are observed in the multilayered filters.