Mirror shell for e.g. collector unit used in microlithography projection system, sets angle between axis of symmetry of cylindrical surface and grids to specific value

摘要

The mirror shell (1) has mirror base that is rotated symmetrical about an axis of symmetry of cylindrical surface, and periodic diffraction grating (11). The periodic diffraction grating comprising grids (13) and grooves (15) is arranged on portion of the mirror base. The angle between the axis of symmetry of cylindrical surface and the grids is less than 5[deg] . Independent claims are included for the following: (1) collector unit; (2) light source unit; (3) manufacturing method of mandrel; (4) mandrel; and (5) manufacturing method of mirror shell.