Patent ID: 6845497
Filing Date: 2005-01-18
Classification: B82Y,G03F,H01J

Abstract:
1. A method of forming patterns wherein a region that can be exposed by an electron beam at one time is defined as a sub-field, and predetermined patterns are formed by exposing sequentially the sub-field at predetermined positions on a substrate to be processed through deflection of the electron beam, said method comprising: a step of creating a first pattern area density map, wherein a whole region of the predetermined patterns is divided into a plurality of first subdivided regions of constant dimensions, a ratio of a pattern area through which the electron beam passes, within one of the first subdivided regions, to one of the first subdivided regions, in whole, is defined as a pattern area density, and pattern area densities for the whole region of the predetermined patterns are rendered into two-dimensional array data made up so as to correspond to each of the first subdivided regions; a step of creating a second pattern area density map, wherein a value calculated on the basis of the pattern area densities of several of the first subdivided regions is a pattern area density of second subdivided regions; and a step of applying exposure such that a deflection position of the sub-field and current density of the electron beam substantially coincide with a deflection position of the sub-field and current density of the electron beam as estimated at the time of exposing the sub-field, with the use of a mask for projection to which modification of patterns is applied by estimating variation in pattern dimensions after electron beam exposure and development by taking into consideration an effect of backscattering of the electron beam, inside the substrate to be processed, by use of an extent of electron beam blur dependent on the deflection position of the electron beam at the time of exposing the sub-field, as corrected on the basis of the first or second pattern area density map and the current density of the electron beam, and by use of a third pattern area density map different from the first and second pattern area density maps.