Fabrication of the hollow SnO2 nanoparticles contained spheres as extreme ultraviolet (EUV) target

Extreme ultraviolet lithography (EUVL) is a promising technology for the volume production of the future integrated circuit. In this paper, hollow multilayer microcapsules which contained tin dioxide nanoparticles were fabricated successfully with layer-by-layer (LBL) technique. Compared with the previous reported results, the obtained capsules have rougher surface structure (60 nm in rms which measured by atomic force microscopy (AFM)) and lost their round shape even in solution because of the existing of the tin dioxide (SnO2) nanoparticles. In order to lighten the mass of the target, heating treatment was introduced. After heating treatment, capsules’ sizes shrank about 28% (the average diameter changed from 4.9 μm to 1.4 μm). The narrowest bandwidth at 13.5 nm emission in EUV region was observed when the capsules were irradiated with CO2 laser with an intensity of 2.9 × 1010 W/cm2, it is a little weaker than the previous result because of the mass difference of the target.