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

Published

April 16, 2008

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

Pub Type

Conferences

Download Paper

Local Download

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 October 12, 2024)