Characterization of optics and masks for the EUV lithography
In the frame of the French EUV program PREUVE, different studies are made on different key aspects of EUV lithography. Aspheric optics are fabricated for the exposure test bench as well as mask blanks. All these objects require Mo/Si multilayer coatings with optimized EUV characteristics. As project partner, SOPRA is developing a commercial table-top soft-X-ray/EUV reflectometer to measure, at wavelength, the reflectivity versus wavelength, angle of incidence and position on the sample. These MoSi multilayers are deposited by magnetron sputtering or ion beam sputtering for the optics and the masks, respectively. Hereafter, some structural characterizations of these two kinds of multilayers are measured and compared. The EUV reflectometer is described in detail and first results are presented in relation with the Mo/Si structural characterizations.
optics masks euv lithography reflectometry