Manufacturing of XEUV mirrors with a sub-nanometer surface shape accuracy

In this paper, first results of finishing EUV mirror substrate surface shape to given parameters using correction methods such as vacuum thin films deposition and local ion-beam etching through the mask are presented. For spherical mirror substrate with radius of curvature R=260 mm and a diameter of 130 mm, obtained values of PV=4.7 nm and RMS=0.6 nm.