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Proceedings Paper

10nm three-dimensional CD-SEM metrology
Author(s): András E. Vladár; John S. Villarrubia; Jasmeet Chawla; Bin Ming; Joseph R. Kline; Scott List; Michael T. Postek
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Paper Abstract

The shape and dimensions of a challenging pattern have been measured using a model-based library scanning electron microscope (MBL SEM) technique. The sample consisted of a 4-line repeating pattern. Lines were narrow (10 nm), asymmetric (different edge angles and significant rounding on one corner but not the other), and situated in a complex neighborhood, with neighboring lines as little as 10 nm or as much as 28 nm distant. The shape cross-section determined by this method was compared to transmission electron microscopy (TEM) and critical dimension small angle x-ray scattering (CD-SAXS) measurements of the same sample with good agreement. A recently-developed image composition method was used to obtain sharp SEM images, in which blur from vibration and drift were minimized. A Monte Carlo SEM simulator (JMONSEL) produced a model-based library that was interpolated to produce the best match to measured SEM images. Three geometrical and instrument parameterizations were tried. The first was a trapezoidal geometry. In the second one corner was significantly rounded. In the last, the electron beam was permitted to arrive with stray tilt. At each stage, the fit to the data improved by a statistically significant amount, demonstrating that the measurement remained sensitive to the new parameter. Because the measured values represent the average unit cell, the associated repeatabilities are at the tenths of a nanometer level, similar to scatterometry and other area-averaging techniques, but the SEM’s native high spatial resolution also permitted observation of defects and other local departures from the average.

Paper Details

Date Published: 14 April 2014
PDF: 11 pages
Proc. SPIE 9050, Metrology, Inspection, and Process Control for Microlithography XXVIII, 90500A (14 April 2014); doi: 10.1117/12.2045977
Show Author Affiliations
András E. Vladár, National Institute of Standards and Technology (United States)
John S. Villarrubia, National Institute of Standards and Technology (United States)
Jasmeet Chawla, Intel Corp. (United States)
Bin Ming, National Institute of Standards and Technology (United States)
Joseph R. Kline, National Institute of Standards and Technology (United States)
Scott List, Intel Corp. (United States)
Michael T. Postek, National Institute of Standards and Technology (United States)


Published in SPIE Proceedings Vol. 9050:
Metrology, Inspection, and Process Control for Microlithography XXVIII
Jason P. Cain; Martha I. Sanchez, Editor(s)

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