Patent ID: 6277542
Filing Date: 2001-08-21
Classification: B82Y,G03F,H01J,Y10S

Abstract:
A method for projection-exposing a pattern onto a sensitive substrate using a charged particle beam and a projection-optical system, the method comprising the steps:(a) defining the pattern on a reticle, the reticle including multiple exposure units each defining a respective portion of the pattern and including at least one multiple-feature exposure unit defining multiple features of the pattern arranged in a high-feature-density portion and a low-feature-density portion of the exposure unit, the low-feature-density portion also defining multiple micro features each sized below a resolution limit of the projection-optical system;(b) illuminating the multiple-feature exposure unit of the reticle using the charged particle beam to produce an imaging beam; and(c) projecting the imaging beam through the projection-optical system onto the sensitive substrate to form an image of the multiple-feature exposure unit on a corresponding region of the sensitive substrate, wherein the micro features transmit charged particles from the reticle to the substrate and thus change a beam-current distribution over the corresponding region of the substrate relative to the beam-current distribution that otherwise would be achieved if the multiple-feature exposure unit lacked the micro features.