Application of electron-beam-induced processes to mask repair

An electron beam technology for repair of Next Generation Lithography masks is described. Deposition of missing material in clear defects is shown with different material characteristics. Etching of opaque defects is demonstrated. The superiority of the electron beam technology to the well established and widely used focused ion beam techniques is discussed. Electron beam repair avoids the unacceptable transmission loss which is generated by focus ion beam techniques especially for 193 nm and 157 nm lithography by Ga-ion implantation. Shrinking dimensions of printable defects require higher resolution than ion beams allow, which is, however, obtained routinely with electron beam systems. Specially designed lenses having low aberrations provide outstanding better signal to noise ratio than ion beam systems. Results on deposition and etching of NGL mask relevant materials like TaN, SiC, Mo/Si, and silicon dioxide is demonstrated. In general 1 keV electrons and a low electron current were used for the etching processes.