Abstract: Apparatus and methods are disclosed for inscribing a pattern on a reticle blank to produce a lithography reticle. As a reticle blank is inscribed using a charged particle beam (e.g., electron beam), some of the incident charged particles pass through the reticle blank and are backscattered from underlying structure (e.g., from a stage used to hold the reticle blank during inscription). These backscattered particles reduce the pattern resolution on the reticle. The present apparatus and methods reduce the number of backscattered particles re-entering the reticle blank, thereby improving pattern resolution.

Abstract: Evaluation methods are disclosed for evaluating the image-forming performance of charged-particle-beam microlithography systems, especially with regard to astigmatism and focus. In an embodiment, a subfield containing an evaluation pattern is subdivided into multiple regions. In the various regions, the respective line-and-space (L/S) pattern elements are oriented such that the elements in one region extend in a direction that intersects the direction, in the object plane of orientation of the pattern element in another region. The evaluation pattern is transferred lithographically to a resist film on a substrate. The developed resist, when observed at a magnification at which individual L/S pattern elements are not resolved, reveals a “shadow region” having a particular profile. The profile is a function of one or more parameters (e.g., astigmatism and focus) of image-forming performance.

Abstract: Apparatus and methods are disclosed for inscribing a pattern on a reticle blank to produce a lithography reticle. As a reticle blank is inscribed using a charged particle beam (e.g., electron beam), some of the incident charged particles pass through the reticle blank and are backscattered from underlying structure (e.g., from a stage used to hold the reticle blank during inscription). These backscattered particles reduce the pattern resolution on the reticle. The present apparatus and methods reduce the number of backscattered particles re-entering the reticle blank, thereby improving pattern resolution.