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Publications

Search Publications by

Ndubuisi George Orji (Fed)

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Displaying 1 - 25 of 76

Spectral Analysis of Line Edge and Line Width Roughness using Wavelets

April 1, 2021
Author(s)
Ndubuisi George Orji
Although line edge and line width roughness (LER/LWR) have been key metrology challenges over the last 15 years, the advent of extreme-ultraviolet lithography (EUV) has increased the importance of its measurement and control. Lithographically printed

Wear comparison of critical dimension-atomic force microscopy tips

March 28, 2020
Author(s)
Ndubuisi G. Orji, Ronald G. Dixson, Ernesto Lopez, Bernd Imer
Nanoscale wear affects the performance of atomic force microscopy (AFM)-based measurements for all applications including process control, nanoelectronics characterization and topography measurements. As such, methods to prevent or reduce AFM tip wear is

Metrology requirements for next generation of semiconductor devices

April 4, 2019
Author(s)
Ndubuisi G. Orji
Although devices based on traditional CMOS architectures are expected to reach their physical limits in the next few years, the devices and materials involved are more complex and difficult to measure than ever before. The nanoscale sizes mean that the

Metrology for the next generation of semiconductor devices

October 12, 2018
Author(s)
Ndubuisi G. Orji, Mustafa Badaroglu, Bryan M. Barnes, Carlos Beitia, Benjamin D. Bunday, Umberto Celano, Regis J. Kline, Mark Neisser, Yaw S. Obeng, Andras Vladar
The semiconductor industry continues to produce ever smaller devices that are ever more complex in shape and contain ever more types of materials. The ultimate sizes and functionality of these new devices will be affected by fundamental and engineering

Spatial Dimensions in Atomic Force Microscopy: Instruments, Effects, and Measurements

August 15, 2018
Author(s)
Ronald G. Dixson, Ndubuisi G. Orji, Ichiko Misumi, Gaoliang Dai
Atomic force microscopes (AFMs) are commonly and broadly regarded as being capable of three dimensional imaging. However, conventional AFMs suffer from both significant functional constraints and imaging artifacts that render them less than fully three

Virtual Metrology White Paper - INTERNATIONAL ROADMAP FOR DEVICES AND SYSTEMS(IRDS)

April 9, 2018
Author(s)
Ndubuisi G. Orji, Yaw S. Obeng, Carlos Beitia, Supika Mashiro, James Moyne
This white paper provides an overview of virtual metrology (VM) and the benefits it can provide, with cost reduction (both capital expenditure and cycle time) being the primary benefit. The white paper also examines some of the issues preventing wider

Contour Metrology using Critical Dimension Atomic Force Microscopy

December 15, 2016
Author(s)
Ndubuisi G. Orji, Ronald G. Dixson, Boon Ping Ng, Andras Vladar, Michael T. Postek
The critical dimension atomic force microscope (CD-AFM) has been proposed as an instrument for contour measurement and verification – since its capabilities are complementary to the widely used scanning electron microscope (SEM). Although data from CD-AFM

Transmission Electron Microscope Calibration Methods for Critical Dimension Standards

October 13, 2016
Author(s)
Ndubuisi G. Orji, Ronald G. Dixson, Domingo I. Garcia-Gutierrez, Bunday Benjamin, M R. Bishop, Michael W. Cresswell, Richard A. Allen, John Allgair
One of the key challenges in critical dimension (CD) metrology is finding suitable dimensional calibration standards. The transmission electron microscope (TEM), which produces lattice-resolved images having scale traceability to the SI (International

Evaluation of Carbon Nanotube Probes in Critical Dimension Atomic Force Microscopes

August 26, 2016
Author(s)
Jinho Choi, Byong Chon Park, Sang Jung Ahn, Dal-Hyun Kim, J Lyou, Ronald G. Dixson, Ndubuisi George Orji, Joseph Fu, Theodore V. Vorburger
The decreasing size of semiconductor features and the increasing structural complexity of advanced devices has placed continuously greater demands on manufacturing metrology-arising both from the measurement challenges of smaller feature sizes and the

Process Optimization for Lattice-Selective Wet Etching of Crystalline Silicon Structures

March 9, 2016
Author(s)
Ronald G. Dixson, William F. Guthrie, Richard A. Allen, Ndubuisi G. Orji, Michael W. Cresswell, Christine E. Murabito
Lattice-selective etching of silicon is used in a number of applications, but it is particularly valuable in those for which the lattice-defined sidewall angle can be beneficial to the functional goals. A relatively small but important niche application is

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit

January 25, 2016
Author(s)
Ronald G. Dixson, Ndubuisi G. Orji, Ryan Goldband
Sidewall sensing in CD-AFMs usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezo actuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine (CMM)

Tip characterization method using multi-feature characterizer for CD-AFM

December 23, 2015
Author(s)
Ndubuisi G. Orji, Hiroshi Itoh, Chumei Wang, Ronald G. Dixson, Sebastian Schmidt, Bernd Irmer, Peter S. Walecki
In atomic force microscopy (AFM) metrology, the tip is a key source of uncertainty. Images taken with an AFM show a change in feature width and shape that depends on tip geometry. This geometric distortion is more pronounced when measuring features with

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit

October 21, 2015
Author(s)
Ronald G. Dixson, Ryan Goldband, Ndubuisi G. Orji
Critical dimension atomic force microscopes (CD-AFMs) use flared tips and two-dimensional sensing and control of the tip-sample interaction to enable scanning of features with near-vertical or even reentrant sidewalls. Features of this sort are commonly

Interactions of Higher Order Tip Effects in CD-AFM Linewidth Metrology

April 30, 2015
Author(s)
Ronald G. Dixson, Boon Ping Ng, Xavier Bonnaud, Ndubuisi G. Orji
A major challenge in critical dimension atomic force microscope (CD-AFM) width metrology is accounting for the effects of the tip on the apparent features in an image. The overall effect of the tip is to broaden the apparent width of lines and narrow the

Technique for AFM Tip Characterization

September 15, 2014
Author(s)
Ndubuisi G. Orji, Ronald G. Dixson, Hiroshi Itoh, Chumei Wang
In atomic force microscopy (AFM) metrology, the scanning tip is a major source of uncertainty. Images taken with an AFM show an apparent broadening of feature dimensions due to the finite size of the tip. An AFM image is a combination of the feature shape

Effects of Lateral Tip Control in CD-AFM Width Metrology

August 12, 2014
Author(s)
Ronald G. Dixson, Boon Ping Ng, Ndubuisi G. Orji
Critical dimension atomic force microscopes (CD-AFMs) use flared tips and two-dimensional sensing and position control of the tip-sample interaction to enable scanning of features with near-vertical or reentrant sidewalls. Sidewall sensing usually involves

2013 ITRS Metrology Roadmap

April 15, 2014
Author(s)
Alain C. Diebold, Ndubuisi George Orji
In 2013 the ITRS Metrology Technical Working Group worked on updating the text and tables of the metrology chapter. New additions include a section on 3D nanometrology, a revised lithography metrology table, and an updated Interconnect section. The

TSV Reveal height and bump dimension metrology by the TSOM method

April 30, 2013
Author(s)
Ravikiran Attota, Haesung Park, Victor H. Vartanian, Ndubuisi G. Orji, Richard A. Allen
Through-focus scanning optical microscopy (TSOM) transforms conventional optical microscopes into truly 3D metrology tools for nanoscale- to- microscale dimensional analysis with nanometer-scale sensitivity. Although not a resolution enhancement method

Distributed Force Probe Bending Model of CD-AFM Bias

April 1, 2013
Author(s)
Vladimir A. Ukraintsev, Ndubuisi George Orji, Theodore V. Vorburger, Ronald G. Dixson, Joseph Fu, Richard M. Silver
Critical Dimension AFM (CD-AFM) is a widely used reference metrology technique. To characterize modern semiconductor devices, small and flexible probes, often 15 nm to 20 nm in diameter, are used. Recent studies have reported uncontrolled and significant

Robust Auto-Alignment Technique for Orientation-Dependent Etching of Nanostructures

May 29, 2012
Author(s)
Craig D. McGray, Richard J. Kasica, Ndubuisi G. Orji, Ronald G. Dixson, Michael W. Cresswell, Richard A. Allen, Jon C. Geist
A robust technique is presented for auto-aligning nanostructures to slow-etching crystallographic planes in materials with diamond cubic structure. Lithographic mask patterns are modified from the intended dimensions of the nanostructures to compensate for