SACP method and particle optical system for performing the method

摘要

An SACP method includes directing a beam of charged particles onto an object surface of an object using a particle optical system, and detecting intensities of particles emanating from the object. The method further includes: (a1) adjusting an excitation of the second beam deflector for adjusting an impingement location of the beam on the object surface; (a2) adjusting an excitation of the first beam deflector for adjusting an angle of incidence of the beam on the object surface without changing the impingement location and detecting the intensity; and (a3) repeating the adjusting of the excitation of the first beam deflector for adjusting the angle of incidence without changing the impingement location such that a corresponding intensity is detected for each of at least 100 different angles of incidence at the same impingement location.

主权项

1. A method, comprising:
directing a beam of charged particles onto an object surface of an object using a particle optical system, the particle optical system comprising: an objective lens configured to focus the beam of charged particles onto the object surface; a first beam deflector located upstream of the objective lens along a beam path of the beam of charged particles; an aberration corrector located between the first beam deflector and the objective lens along the beam path; and a second beam deflector located downstream of the aberration corrector along the beam path; detecting intensities of particles emanating from the object; (a1) adjusting an excitation of the second beam deflector to adjust an impingement location of the beam on the object surface; (a2) adjusting an excitation of the first beam deflector to adjust an angle of incidence of the beam on the object surface without changing the impingement location and detecting the intensity; (a3) repeating (a2) so that a corresponding intensity is detected for each of at least 100 different angles of incidence at the same impingement location; and using excitation signals to excite a Wien filter, the excitation signals having a period of less than 1/100 second, wherein the Wien filter is upstream of the aberration corrector in the beam path of the beam of the charged particles.