Apparatus and method for obtaining topographical dark-field images in a scanning electron microscope

A method for dark field imaging of a substrate surface, the method comprising:

• generating a primary electron beam;
• deflecting the primary electron beam so as to scan the primary electron beam over the substrate surface whereby secondary and/or backscattered electrons are emitted from the substrate surface, said emitted electrons forming a scattered electron beam;
• separating the scattered electron beam from the primary electron beam;
• passing the scattered electron beam through a cooperative arrangement including at least a ring-like element, a first grid, and a second grid, the ring-like element and the first and second grids each comprising conductive material;
• and
• detecting the scattered electron beam by a segmented detector after the scattered electron beam passes through the cooperative arrangement.

An automated inspection apparatus for dark field (topographical) imaging of a substrate surface, the apparatus comprising:

• means for generating a primary electron beam;
• means for deflecting the primary electron beam so as to scan the primary electron beam over the substrate surface whereby secondary and/or backscattered electrons are emitted from the substrate surface, said emitted electrons forming a scattered electron beam;
• means for separating the scattered electron beam from the primary electron beam;
• means for passing the scattered electron beam through a cooperative arrangement including at least a ring-like element, a first grid, and a second grid, the ring-like element and the first and second grids each comprising conductive material;
• and
• means for detecting the scattered electron beam by a segmented detector after the scattered electron beam passes through the cooperative arrangement.