Publication
SPIE Advanced Lithography 2015
Conference paper

Forbidden pitches: Causes, source optimization, and their role in design rules

View publication

Abstract

Forbidden pitches are the result of unwanted, non-linear effects that limit yield and not always well understood. Yet, as approximations, they are implicitly deployed through design rules. Many believe they result as a consequence of more complicated light sources. We develop an analytical model of aerial image quality as a function of light source. We show the effect is most pronounced for a point light source, the simplest of all. We develop a method to improve print image quality by illumination source optimization, and show promising first results. Additionally, it is shown how design rules capture forbidden pitches unsatisfactorily.

Date

Publication

SPIE Advanced Lithography 2015

Authors

Share