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Displaying 51 - 66 of 66

Statistical Uncertainty Analysis of Key Comparison CCEM-K2

April 1, 2003
Author(s)
Nien F. Zhang, N Sedransk, Dean G. Jarrett
The details of a statistical uncertainty analysis applied to key comparison CCEM-K2 are reported. The analysis presented here provides an approach for addressing known correlations which have been of concern in reporting key comparison results

A Study on the Variance Estimation for a Stationary Process in SPC

February 1, 2003
Author(s)
Nien F. Zhang
Recently, statistical process control (SPC) methodologies have been developed to accommodate autocorrelated data. To construct control charts for stationary process data, the process variance needs to be estimated. For an independently identically

Statistical Uncertainty Analysis of CCEM-K2 Comparisons of Resistance Standards

June 1, 2002
Author(s)
Nien F. Zhang, N Sedransk, Dean G. Jarrett
Details of the statistical uncertainty analysis applied to key comparison CCEM-K2 are reported. Formulas were derived to determine the uncertainty of the combined difference between the measurements of multiple artifacts by an NMI and the corresponding

Statistical Process Monitoring for Autocorrelated Data

October 1, 2001
Author(s)
Nien F. Zhang
In the past years statistical process methodologies have been widely used in industry for process monitoring. However, the assumption that the process data are statistically independent is often invalid. This article discusses the approaches to deal with

Reference Material 8091: New Scanning Electron Microscope Sharpness Standard

August 1, 2001
Author(s)
Andras Vladar, Michael T. Postek, Nien F. Zhang, Robert D. Larrabee, Samuel N. Jones, Russell E. Hajdaj
All scanning electron microscope-based inspection instruments, whether they are in a laboratory or on the production line, slowly lose their performance and then the instrument is no longer capable of providing as good quality, sharp images as before. This

Reference Material 8091: New Scanning Electron Microscope Sharpness Standard

August 1, 2001
Author(s)
Andras Vladar, Michael T. Postek, Nien F. Zhang, Robert D. Larrabee, Samuel N. Jones, Russell E. Hajdaj
Reference Material (RM 8091) is intended primarily for use in checking the sharpness performance of scanning electron microscopes. It is supplied as a small, approximately 2 mm x 2 mm diced semiconductor chip. This sample is capable of being mounted

Bayesian Approach to Combining Results From Multiple Methods

January 1, 2001
Author(s)
Hung-Kung Liu, Nien F. Zhang
Many solutions to the problem of estimating the consensus mean from the results of multiple methods or laboratories have been proposed. In a Bayesian analysis, the consensus mean is specified through probabilistic dependency as either a ¿parent¿ or a

An Approach to Combining Results from Multiple Methods Motivated by the ISO GUM

August 1, 2000
Author(s)
M Levenson, D L. Banks, K Eberhardt, L M. Gill, William F. Guthrie, Hung-Kung Liu, M Vangel, James H. Yen, Nien F. Zhang
The problem of determining a consensus value and its uncertainty from the results of multiple methods or laboratories is discussed. Desirable criteria of a solution are presented. A solution based on the ISO Guide to the Expression of Uncertainty in

Image Sharpness Measurement in Scanning Electron Microscope - Part III

July 1, 1999
Author(s)
Samuel N. Jones, Robert D. Larrabee, Michael T. Postek, Andras Vladar, Nien F. Zhang
Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. Testing and proving that the instrument is performing at a satisfactory level of sharpness is an

Comparisons of Control Charts for Autocorrelated Data

January 1, 1999
Author(s)
Nien F. Zhang
Recently, statistical process control (SPC) methodolgies have been developed to accommodate autocorrelated data. A primary method to deal with autocorrelated data is the use of residual charts. Although this methodology has the advantage that it can be

Blind Men and Elephants: Six Approaches to TREC Data

October 28, 1998
Author(s)
D L. Banks, Paul D. Over, Nien F. Zhang
The paper reviews six recent efforts to better understand performance measurements on information retrieval (IR) within the framework of the Text REtrieval Conferences (TREC): analysis of variance, cluster analyses, rank correlations, beadplots

Statistical Measure for the Sharpness of the SEM Image

July 1, 1997
Author(s)
Nien F. Zhang, Michael T. Postek, Robert D. Larrabee
Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. Testing and proving that the instrument is performing at a satisfactory level of sharpness is an

New Algorithm for the Measurement of Pitch in Metrology Instruments

May 1, 1996
Author(s)
Nien F. Zhang, Michael T. Postek, Robert D. Larrabee, L Carroll, William J. Keery
Traditionally, the measurement of pitch in metrology instruments is thought to be a benign self-compensating function. However, as the measurement uncertainty of metrology instruments is pushed to the nanometer level, evaluation of the performance of the

Statistical Models for Estimating the Measurement of Pitch in Metrology Instruments

January 1, 1996
Author(s)
Nien F. Zhang, Michael T. Postek, Robert D. Larrabee
The measurement of pitch in metrology instruments is through to be a benign self-compensating function. In the course of issuing the new scanning electron microscope standard SRM 2090, a new algorithm for the measurement of pitch was developed. This is