Serif mask design methodology based on enhancing high spatial frequency contribution for improved printability
US6214494A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1998 |
| Grant date | Apr 10, 2001 |
| Priority date | — |
| Expiry date | Oct 7, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/36
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A proximity correction serif design methodology is described that provides improved inner and outer corner rounding, line end shortening, as well as improvements in more general undesirable two-dimensional shape distortions introduced into the lithographic printing process due to proximity effects. Using this method, exact solutions are shown for the specialized cases of either coherent or incoherent illumination exposing a hypothetical resist that develops via a simple diffusion like mechanism. The basis of this method for predicting the positions and shapes of serifs is tied to the need to increase the components of high spatial frequency that are essentially lost due to diffraction, diffusion, dissolution, and etching related effects. The correct amount to increase the spatial components is determined in the coordinate space and makes use of an empirical characterization of these physical factors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.