Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Optical Through-Focus Technique that Differentiates Small Changes in Line Width, Line Height and Sidewall Angle for CD, Overlay, and Defect Metrology Applications

Published

Author(s)

Ravikiran Attota, Richard M. Silver, Bryan M. Barnes

Abstract

We present a new optical technique for dimensional analysis of sub 100 nm sized targets by analyzing through-focus images obtained using a conventional bright-field optical microscope.  We present a method to create through-focus image maps (TFIM) using optical images, which we believe unique for a given target. Based on this we present a library matching method that enables us to determine all the dimensions of an unknown target. Differential TFIMs of two targets are distinctive for different dimensional differences and enable us to uniquely identify the dimension that is different between them. We present several supporting examples using optical simulations and experimental results. This method is expected to be applicable to a wide variety of targets and geometries.
Proceedings Title
Proceedings of SPIE, Metrology, Inspection, and Process Control for Microlithography XXII, John Allgair, Editor
Volume
6922
Issue
2
Conference Dates
February 24-29, 2008
Conference Location
San Jose, CA
Conference Title
Advanced Lithograpgy

Keywords

Through-focus image map, Optical CD (OCD) metrology, Overlay, Defect analysis, Library matching, Optical microscope, Optical inspection, Process control

Citation

Attota, R. , Silver, R. and Barnes, B. (2008), Optical Through-Focus Technique that Differentiates Small Changes in Line Width, Line Height and Sidewall Angle for CD, Overlay, and Defect Metrology Applications, Proceedings of SPIE, Metrology, Inspection, and Process Control for Microlithography XXII, John Allgair, Editor, San Jose, CA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=824634 (Accessed May 29, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created April 16, 2008, Updated February 19, 2017