Proximity effect correction in electron-beam lithography

TLDR: In this paper, the relationship between self-consistent dose correction and typical correction exposure (GHOST) is described, and two alternative dose correction schemes with attractive attributes exist, although they are not as well known.

Abstract: Many techniques have been proposed for the reduction or correction of the proximity effect. These include the use of an appropriate beam energy, multilayer resists, dose correction, and correction exposures. Here, special emphasis is placed on dose correction schemes. In particular, the relationship between these and a typical correction exposure scheme (GHOST) is described. The popular "self-consistent" schemes are in widespread use. However, alternative dose correction schemes with attractive attributes exist, although they are not as well known. Two of these are described. One treats electron lithography as a form of incoherent imaging, characterized by a modulation transfer function (MTF). The method consists of transforming the pattern data to account for this MTF, thus eliminating the proximity effect. This scheme is both computationally efficient and accurate. The other scheme is an extension of GHOST in which dose corrections are computed by simulating the effects of a correction exposure: it too is fast and accurate.