Patent ID: 6218664
Filing Date: 2001-04-17
Classification: H01J

Abstract:
A particle-optical apparatus which includesa particle source for producing a primary beam (22) of electrically charged particles which travel along an optical axis (4) of the apparatus,a specimen holder for a specimen (18) to be irradiated by means of the apparatus,a focusing device (14, 16) for forming a focus of the primary beam in the vicinity of the specimen holder by means of electrostatic electrodes,a beam deflection system (10, 12) for deflecting the primary beam,detection means (6) for detecting electrically charged particles emanating from the specimen in response to the incidence of the primary beam, which detection means are arranged ahead of the focusing device, viewed in the propagation direction of the electrically charged particles in the primary beam, characterized in thatthe beam deflection system (10, 12) is arranged between the detection means (6) and said electrostatic electrodes (14, 16) of the focusing device, andthat the beam deflection system includes electrodes (10, 12) for deflecting the primary beam by means of at least two electrical deflection fields which have a mutually opposed direction component.