PYRAMID: A hierarchical approach to proximity effect correction: Review and update

Proximity effect refers to blurring of the written pattern due to electron scattering in E-beam lithography. As the minimum feature size in a circuit pattern is continuously reduced as an effort to increase circuit density, the proximity effect has become a serious problem. Without an efficient proximity effect correction method, the density (capacity) of a circuit pattern that can be fabricated will be significantly limited. In the future, proximity effect correction is expected to be an essential step for nano-fabrication in E-beam and optical lithography. A hierarchical approach to proximity effect correction, named PYRAMID, was proposed and its first version, PYRAMID 1.0, was completed 1996. In this article, the PYRAMID approach is reviewed and some of the recent research efforts are to be described.