KLA Corporation
Method and Apparatus for EUV Mask Inspection

Abstract:

A method for producing a protective buffer flow in an EUV light source and an EUV mask inspection apparatus are provided. The method includes directing light along a light path from the EUV light source toward a collector. A first buffer gas from a buffer gas injector is injected through a plurality of through holes in the collector. The first buffer gas is directed away from a surface of the collector. A second buffer gas is injected from a ring manifold arranged peripherally to the collector and arranged a first distance toward the light path in relation to the collector. The second buffer gas is directed away from the surface of the collector. The first distance corresponds to a distance from the collector where the first buffer gas merges into a single flow.