Patent ID: 6756182
Filing Date: 2004-06-29
Classification: B82Y,G03F,H01J,Y10S

Abstract:
In a method for performing charged-particle-beam (CPB) microlithography in which a pattern for a layer of a microelectronic device to be formed on a substrate, sensitized by having a layer of resist, is defined on a segmented reticle that is either a scattering-stencil reticle or a scattering-membrane reticle, and selected regions of the reticle are individually illuminated with a CPB illumination beam to produce a corresponding patterned beam, wherein most of the charged particles in the patterned beam that are highly scattered during passage through the reticle are blocked by a contrast aperture from reaching the sensitive substrate, while charged particles that are not scattered and weakly scattered during passage through the reticle pass through the contrast aperture and are focused as a projected image on the sensitive substrate, a method for reducing Coulomb effects on the projected image, comprising:for exposing the pattern, reducing a beam current of the patterned beam reaching the sensitive substrate, relative to a beam current actually passing through the reticle, to 50% or less by performing the steps of (a) establishing the pattern, as defined on the reticle, as a normal-tone pattern or as an inverted-tone pattern; and (b) establishing the resist on the substrate as a positive or negative resist.