Automated focusing of electron image
AssigneeKLA-Tencor Technologies Corporation
InventorsGabor D. Toth, Varoujan Chakarian, Douglas K. Masnaghetti
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Abstract
One embodiment disclosed relates to a method for automated focusing of an electron image. An EF cut-off voltage is determined. In compensation for a change in the EF cut-off voltage, a focusing condition is adjusted. Adjusting the focusing condition may comprise, for example, adjusting a wafer bias voltage in correspondence to the change in cut-off voltage. Another embodiment disclosed relates to a method for automated focusing of an electron image in a scanning electron imaging apparatus. A focusing condition of a primary electron beam in a first image plane is varied so as to maximize an intensity of a secondary electron beam through an aperture in a second image plane.
Claims7
A method for automated focusing of an electron image in a scanning electron imaging apparatus, the method comprising:
- varying a focusing condition of a primary electron beam in a first image plane so as to maximize an intensity of a secondary electron beam through an aperture in a second image plane;
- turning off scanning of the primary beam;
- and
- setting a deflector for the secondary beam to a focusing mode upon initiation of the automated focusing.
Dependencies are inferred from the claim text.