Patent ID: 6388261
Filing Date: 2002-05-14
Classification: B82Y,H01J

Abstract:
A charged-particle-beam microlithography apparatus, comprising:(a) an illumination-optical system situated and configured relative to a charged-particle-beam source and a pattern-defining reticle so as to direct a charged-particle illumination beam from the source to illuminate a region of the pattern defined by the reticle; (b) a projection-optical system situated on an optical axis extending between the reticle and a sensitive substrate, the projection optical system being configured to receive an imaging beam, generated by passage of a portion of the illumination beam through the illuminated region of the reticle, and cause the imaging beam to form an image of the illuminated region on a corresponding region of the sensitive substrate; and (c) the projection-optical system comprising a stigmator lens comprising at least two stigmator coils each generating, when energized, a respective magnetic-field strength and each exhibiting a respective convergence or divergence of the imaging beam, the stigmator lens having a principal plane at a position on the optical axis, the position being a function of a ratio of the respective magnetic-field strengths and respective degrees of convergence or divergence exhibited by the stigmator coils.