Normal-incidence spectroscopic ellipsometry and polarized reflectometry for measurement and control of photoresist critical dimension

Autor: Thomas Gubiotti, James M. Holden, Ton Kiers, Mircea V. Dusa, William A. McGahan
Rok vydání: 2002
Předmět:
Zdroj: SPIE Proceedings.
ISSN: 0277-786X
Popis: We report here on initial results for the characterization and modeling of 100 nm lithography features based on normal incidence spectroscopic ellipsometry and polarized reflectometry. In this work, a set of wafers was exposed as focus-exposure and separate focus or exposure matrices to create resists patterns with extremely small variations in CD and pattern shape. These variations were generated along scan, within slit and across full wafer. Optical CD scatterometry was used to extract critical feature parameters such as complete shape and associated linear dimensions. Extracted pattern parameters were compared to FIB sections and used to predict lithography process latitudes. We explore effects of using multi normal incidence ellipsometric signals with various profile models to increase accuracy of extracted lithography parameters. We propose a metric for identifying effects of scan-dynamic does and focus variations upon slit-intrafield and scan- intrafield CD errors. This has been tested over ranges of defocus and exposure that are larger than typical FE latitudes of 100 nm features. As a result of spectroscopic scatterometry calculations of pattern shape, we identified pattern shape variations caused by dose and defocus that are clearly coupled to changes in feature size. These could be used for unique determination of dose-focus deviations using scatterometry-extracted information from measurements of a grating structure.
Databáze: OpenAIRE