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Search Publications by: John S. Villarrubia (Fed)

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Displaying 26 - 50 of 106

Can We Get 3D CD Metrology Right?

April 19, 2012
Author(s)
Andras Vladar, John S. Villarrubia, Michael T. Postek, Petr Cizmar
Our world is three-dimensional, so are the integrated circuits (ICs), they have always been. In the past, for a long time, we’ve been very fortunate, because it was enough to measure the critical dimension (CD), the width of the resist line to keep IC

SEM imaging of ultra-high aspect ratio hole features

March 29, 2012
Author(s)
John S. Villarrubia, Aron Cepler, Benjamin D. Bunday, Bradley Thiel
In-line, non-destructive process control metrology of high aspect ratio (HAR) holes and trenches has long been a known gap in metrology. Imaging the bottoms of at-node size beyond 10:1 AR contact holes in oxide has not yet been demonstrated. Nevertheless

Stylus Tip-Size Effect on the Calibration of Periodic Roughness Specimens with Rectangular Profiles

March 21, 2012
Author(s)
Thomas B. Renegar, Johannes A. Soons, Balasubramanian Muralikrishnan, John S. Villarrubia, Xiaoyu A. Zheng, Theodore V. Vorburger, Jun-Feng Song
Stylus instruments are widely used for surface characterization. It is well known that the size and shape of the stylus tip affects the measured surface geometry and parameters. In most cases, increasing the tip size decreases the measured Ra value because

VCI Simulation with Semiconductor Device Models: Test Report

February 29, 2012
Author(s)
John S. Villarrubia
JMONSEL, an electron beam imaging simulator, has been modified to permit conducting regions of a sample to be designated as unconnected to an external source or sink of charge (floating) or, alternatively, to be connected with a user-specified relaxation

Proximity-associated errors in contour metrology

March 31, 2010
Author(s)
John S. Villarrubia, Ronald G. Dixson, Andras Vladar
In contour metrology the CD-SEM (critical dimension scanning electron microscope) assigns a continuous boundary to extended features in an image. The boundary is typically assigned as a simple function of the signal intensity, for example by a brightness

Nanometrology Solutions Using an Ultra-High Resolution In-lens SEM

September 1, 2009
Author(s)
Michael T. Postek, Andras Vladar, John S. Villarrubia
The imaging and measurement of nanostructures such as particles, carbon nanotubes, and quantum dots have placed new demands on the high resolution imaging capabilities of scanning electron microscopes. A barrier to accurate dimensional metrology is the

Sensitivity of SEM width measurements to model assumptions

March 31, 2009
Author(s)
John S. Villarrubia, Zejun Ding
The most accurate width measurements in a scanning electron microscope (SEM) require raw images to be corrected for instrumental artifacts. Corrections are based upon a physical model that describes the sample-instrument interaction. Models differ in their

Blind estimation of general tip shape in AFM imaging

December 1, 2008
Author(s)
Fenglei Tian, Xiaoping Qian, John S. Villarrubia
The use of flared tip and bi-directional servo control in some recent atomic force microscopes (AFM) has made it possible for these advanced AFMs to image structures of general shapes with undercuts and reentrant surfaces. Since AFM images are distorted

Line Width Roughness and Cross Sectional Measurements of Sub-50 nm Structures with CD-SAXS and CD-SEM

March 24, 2008
Author(s)
Chengqing C. Wang, Ronald L. Jones, Kwang-Woo Choi, Christopher L. Soles, Eric K. Lin, Wen-Li Wu, James S. Clarke, John S. Villarrubia, Benjamin Bunday
Critical dimension small angle x-ray scattering (CD-SAXS) is a measurement platform which is capable of measuring the average cross section and sidewall roughness in patterns ranging from (10 to 500) nm in pitch with sub nm precision. These capabilities

Line Edge Roughness Characterization of Sub-50nm Structures Using CD-SAXS: Round-Robin Benchmark Results

January 1, 2007
Author(s)
Chengqing C. Wang, J C. Roberts, Robert Bristol, B Bunday, Ronald L. Jones, Eric K. Lin, Wen-Li Wu, John S. Villarrubia, Kwang-Woo Choi, James S. Clarke, Bryan J. Rice, Michael Leeson
he need to characterize line edge and line width roughness in patterns with sub-50 nm critical dimension challenges existing platforms based on electron microscopy and optical scatterometry. The development of x-ray based metrology platforms provides a

Bias Reduction in Roughness Measurement through SEM Noise Removal

March 24, 2006
Author(s)
R Katz, C D. Chase, R Kris, R Peltinov, John S. Villarrubia, B Bunday
The importance of Critical Dimension (CD) roughness metrics such as Line and Contact edge roughness (LER, CER) and their associated width metrics (LWR, CWR) have been dealt with widely in the literature and are becoming semiconductor industry standards

Advanced Metrology Needs for Nanotechnology and Nanomanufacturing

November 1, 2005
Author(s)
Michael T. Postek, John S. Villarrubia, Andras Vladar
Advances in fundamental nanoscience, design of nanomaterials, and ultimately manufacturing of nanometer scale products all depend to some degree on the capability to accurately and reproducibly measure dimensions, properties, and performance

Scanning electron microscope dimensional metrology using a model-based library

November 1, 2005
Author(s)
John S. Villarrubia, Andras Vladar, Michael T. Postek
The semiconductor electronics industry places significant demands upon secondary electron imaging to obtain dimensional measurements that are used for process control or failure analysis. Tolerances for measurement uncertainty and repeatability are smaller

Issues in Line Edge and Linewidth Roughness Metrology

September 9, 2005
Author(s)
John S. Villarrubia
In semiconductor electronics applications, line edge and linewidth roughness are generally measured using a root mean square (RMS) metric. The true value of RMS roughness depends upon the length of edge or line that is measured and the chosen sampling

A Simulation Study of Repeatability and Bias in the CD-SEM

July 1, 2005
Author(s)
John S. Villarrubia, Andras Vladar, Michael T. Postek
Abstract: The ability of a critical dimension scanning electron microscope (CD-SEM) to resolve differences in the widths of two lines depends on the instrument?s measurement repeatability and any sample dependent biases. The dependence of repeatability and

Unbiased Estimation of Linewidth Roughness

May 1, 2005
Author(s)
John S. Villarrubia, B Bunday
Line width roughness (LWR) is usually estimated simply as three standard deviations of the line width. The effect of image noise upon this metric includes a positive nonrandom component. The metric is therefore subject to a bias or ?systematic error? that

Scanning Electron Microscope Dimensional Metrology Using a Model-Based Library

April 1, 2005
Author(s)
John S. Villarrubia, Andras Vladar, Michael T. Postek
The semiconductor electronics industry places significant demands upon secondary electron imaging to obtain dimensional measurements that are used for process control or failure analysis. Tolerances for measurement uncertainty and repeatability are smaller

Influence of Focus Variation on Linewidth Measurements

March 3, 2005
Author(s)
M Tanaka, John S. Villarrubia, Andras Vladar
The influence of spatial resolution on line width measurements in the critical dimension scanning electron microscope (CD-SEM) was investigated experimentally. Measurement bias variation and measurement repeatabilities of four edge detection algorithms

Issues in Line Edge and Linewidth Roughness Metrology

January 1, 2005
Author(s)
John S. Villarrubia
In semiconductor electronics applications, line edge and linewidth roughness are generally measured using a root mean square (RMS) metric. The true value of RMS roughness depends upon the length of edge or line that is measured and the chosen sampling

Scanning Electron Microscope Dimensional Metrology using a Model-based Library

January 1, 2005
Author(s)
John S. Villarrubia, Andras Vladar, Michael T. Postek
The semiconductor electronics industry places significant demands upon secondary electron imaging to obtain dimensional measurements that are used for process control or failure analysis. Tolerances for measurement uncertainty and repeatability are smaller

Test of CD-SEM Shape-Sensitive Linewidth Measurement

July 1, 2004
Author(s)
John S. Villarrubia, Andras Vladar, Michael T. Postek
In a model-based library (MBL) approach to scanning electron microscope (SEM) linewidth measurement, a library of simulation results for a range of lineshapes is searched for a match to the measured image of the unknown line. Compared to standard