Paper
29 April 2004 Necessary nonzero lithography overlay correctables for improved device performance for 110nm generation and lower geometries
Igor Jekauc, Bill Roberts, Paul Young, Paul Jowett, Reuben Ferguson, Sean Louks
Author Affiliations +
Abstract
Minimizing alignment errors in the past has been fairly straightforward. The aim has always been to drive the overlay model correctables to zero either instantly or after a number of lots processed in a short time frame depending on the controller setup. Methods for improving alignment have included minimizing components of variation tied to the exposure tool, metrology tool, process setup, or the model itself. Instead of working on these components, a less expensive alternative for improving the final outcome as represented by the device performance may be not to minimize the overlay correctables but to instead drive to a specific target as defined by the process window around any such correctable. This paper will briefly show that lithography at present geometries is no longer the sole controller of alignment but that in fact other areas such as films, etch, and CMP influence alignment significantly. It will also be shown that in certain instances vertical wafer topography or feature profile may create device asymmetries, which may be compensated partially through application of non-zero overlay correctables. Coping with decreased overlay performance and methodology for controlling overlay biases is also shown.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Igor Jekauc, Bill Roberts, Paul Young, Paul Jowett, Reuben Ferguson, and Sean Louks "Necessary nonzero lithography overlay correctables for improved device performance for 110nm generation and lower geometries", Proc. SPIE 5378, Data Analysis and Modeling for Process Control, (29 April 2004); https://doi.org/10.1117/12.535258
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CITATIONS
Cited by 2 scholarly publications.
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KEYWORDS
Optical alignment

Overlay metrology

Lithography

Semiconducting wafers

Etching

Metrology

Metals

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