Reticle backside inspection method

A reticle inspection system, comprising:

• a reticle stage on which a reticle to be scanned is located;
• a scanning light source to direct radiation at the reticle;
• a light detector to detect radiation reflected and/or scattered from a surface of the reticle;
• a controller programmed to control the reticle inspection system to repeat scanning of the surface of the reticle a plurality of times at a plurality of different heights to obtain a plurality of images;
• and
• a processor programmed to:
• combine the plurality of images to obtain a surface profile image of the reticle, and
• analyze the surface profile image to determine whether to accept the reticle, repair the reticle, or reject the reticle.

An apparatus for obtaining a surface profile map of a reticle surface, the apparatus comprising:

• a scanner comprising a light source and a beam steering mechanism configured to scan light provided by the light source across the reticle surface at a prescribed height of the reticle surface;
• an imaging device configured to detect light reflected and/or scattered by the reticle surface;
• a controller programmed to cause the imaging device to obtain a plurality of images of the reticle surface at a plurality of heights;
• and
• a processor programmed to obtain the surface profile map of the reticle surface by combining the plurality of images of the reticle surface at the plurality of heights.