Electron beam lithography system with low brightness

Abstract

An electron beam system for direct writing applications employs an electron gun having a large emitting surface compared to the prior art and a brightness approximately two orders of magnitude less than prior art systems to illuminate an initial aperture uniformly with a slightly diverging beam that passes efficiently through the aperture, a first set of controllable deflectors to scan the beam over the reticle parallel to the system axis, impressing the pattern of a subfield of the reticle in each exposure, in which a first variable axis lens focuses an image of the initial aperture on the reticle, a second variable axis lens collimates the patterned beam, a second set of controllable deflectors to bring the beam back to an appropriate position above the wafer, and a third variable axis lens to focus an image of the reticle subfield on the wafer, together with correction elements to apply aberration corrections that may vary with each subfield, thereby providing high throughput from the use of parallel processing of the order of 10.sup.7 pixels per subfield with the low aberration feature of the variable axis lens and the ability to tailor location-dependent corrections that are associated with gaussian systems that stitch the image pixel by pixel.

Dependencies are inferred from the claim text.