Method of detecting and adjusting exposure conditions of charged particle exposure system and such a system

摘要

A charged particle exposure system comprises an electron gun, an irradiation optical system, an incident mask deflector, a stencil mask, an irradiation mask provided on an incident side of the deflector, a reduction optical system, and a stage. The stencil mask has a group of normal patterns and at least two mark patterns. Images of the mark patterns are transferred onto the surface of a sample on the stage. A reduction ratio and rotational angle of the transferred images are computed according to a distance between the images, positional relations of the images, a known distance between the mark patterns on the stencil mask, and known positional relations of the mark patterns on the stencil mask. Based on the computed reduction ratio and rotational angle, exposure conditions of the exposure system are adjusted. IMAGE