Transistor layout configuration effect on actual gate LER

Guy Ayal*, Eitan Shauly, Israel Rotshtein, Ovadya Menadeva, Amit Siany, Ram Peltinov, Yosi Shacham-Diamand

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


The importance of Line Edge Roughness (LER) and Line Width Roughness (LWR) has long surpassed its effect on process control. As devices scale down, the roughness effects have become a major hindrance for further advancement along Moore's law. Many studies have been conducted over the years on the sensitivity of LER to various changes in the materials and the process, which have been considered the main way to tackle the problem - especially through Photoresist improvement. However, despite the increased development of DFM tools in recent years, limited research was done as to LER sensitivity to layout, and the research that was done was limited to proximity effects. In this paper, we study the sensitivity of LER to the layout around the transistor, defined by the gate structure of poly over AA (Active Area). Using different types and geometries of transistors, we found that the poly-gate LER is sensitive to the structure of the Active Area around it (source/drain from gate to contact, both shape and length). Using local LER measurement (moving standard deviation of poly edge location), we found a clear correlation between LER value and the length of the AA/STI boundary located at a close range. Longer AA edges yield higher LER, as proved by comparing gate LER of dog-bone transistor with classical transistor. Based on these results, we suggest that LER is sensitive not only to proximity effects, but also to the layout of underlying layers, through the effect of light scattering of the edges during the lithographic process.

Original languageEnglish
Title of host publicationDesign for Manufacturability through Design-Process Integration III
StatePublished - 2009
EventDesign for Manufacturability through Design-Process Integration III - San Jose, CA, United States
Duration: 26 Feb 200927 Feb 2009

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceDesign for Manufacturability through Design-Process Integration III
Country/TerritoryUnited States
CitySan Jose, CA


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