Apparatus and methods for high-resolution electron beam imaging

A method of forming an incident electron beam for a high-resolution electron beam apparatus, the method comprising:

• emitting electrons from a source;
• focusing the electrons from the source into an electron beam;
• limiting a source emission angle of electrons in the electron beam using a beam limiting aperture;
• limiting an energy spread of the electrons in the electron beam using an energy filter to form an energy-filtered electron beam;
• and
• focusing the energy-filtered electron beam onto a spot on a surface of a target substrate using an objective lens.

A stigmatic Wien filter comprising:

• a first pair of magnetic cores wound by conductive coils and configured along a first axis;
• a first pair of curved conductive plates configured along the first axis;
• a second pair of magnetic cores wound by conductive coils and configured along a second axis;
• and
• a second pair of curved conductive plates configured along the second axis,
• wherein the first and second axes are perpendicular to each other.

A stigmatic Wien filter comprising:

• a multipole deflector;
• a first pair of magnetic yokes wound by conductive coils and configured along a first axis;
• and
• a second pair of magnetic yokes wound by conductive coils and configured along a second axis,
• wherein the first and second axes are perpendicular to each other, and
• wherein the first and second pairs of magnetic yokes are configured with an overlap.