Chris A. Mack

Chris A. Mack
University of Texas at Austin | UT · Department of Chemical Engineering

PhD
CTO at Fractilia

About

356
Publications
62,056
Reads
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4,299
Citations
Citations since 2016
64 Research Items
1737 Citations
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
Introduction
Additional affiliations
May 2005 - present
Lithoguru.com
Position
  • Gentleman Scientst
February 2001 - May 2005
KLA Corporation
Position
  • Vice President
September 1991 - present
University of Texas at Austin
Position
  • Professor (Associate)

Publications

Publications (356)
Article
Full-text available
Linewidth Roughness (LWR) remains a difficult challenge for improvement in all resist materials. In previous work we focused on the impact of key components of LWR by analyzing the Power Spectral Density (PSD) curves which can be obtained using Fractilia’s MetroLER computational software. By measuring the unbiased PSD (with SEM image noise removed)...
Article
Full-text available
كُتبت هذه المقالة بمناسبة مرور ثَلَاثُمِائَة وَخَمْسُونَ عاماً على ظهور أول مجلة علمية، فهي توثق لجوانب مهمة حول نشأة، وسمات، النموذج الأول من المَجَلَّاِت العلمية، وتطورها، بالتركيز على مَجَلَّة المعاملات الفلسفية (Philosophical Transactions)، ورأيت ضرورة ترجمة هذه المقالة للغة العربية أملاً في توسيع إطار الإفادة منها؛ سيما مع ندرة الكتابات العربي...
Book
How to Write a Good Scientific Paper?
Article
Measuring line-edge roughness in a top-down scanning electron microscope (SEM) is complicated by noise in the SEM image, which biases the measured roughness. When either the roughness is small or the noise is large, it can become very difficult to separate noise from roughness to produce an unbiased estimate of the feature roughness. Synthetic SEM...
Article
Linewidth roughness (LWR) remains a difficult challenge for improvement in all resist materials. In this paper, we intend to focus on the impact of key components of LWR by analyzing the power spectral density (PSD) curves which can be obtained using Fractilia's MetroLER computational software. We will study systematic changes to ArF resist formula...
Article
Power spectral density (PSD) analysis is playing a more critical role in the understanding of line-edge roughness and linewidth roughness (LWR) in a variety of applications across the industry. It is an essential step to get an unbiased LWR estimate, as well as an extremely useful tool for process and material characterization. However, PSD estimat...
Article
The measurement of roughness of small lithographic patterns is biased by noise in the scanning electron microscopes (SEMs) used to make the measurements. Unbiasing the roughness measurement requires the measurement and subtraction of the image noise based on its unique frequency behavior. Improvement to prior white noise removal is achieved by appl...
Article
Pattern roughness is a major problem in advanced lithography for semiconductor manufacturing, especially for the insertion of extreme ultraviolet (EUV) lithography as proposed in the coming years. Current approaches to roughness reduction have not yielded the desired results. Here, a global optimization approach is proposed, taking advantage of the...
Article
Full-text available
Article
Most scanning electron microscope (SEM) measurements of pattern roughness today produce biased results, combining the true feature roughness with noise from the SEM. Further, the bias caused by SEM noise changes with measurement conditions and with the features being measured. The goal of unbiased roughness measurement is to both provide a better e...
Book
The book can be downloaded as a pdf (free) here: http://spie.org/Publications/Book/2317706
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Article
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Article
Measurement of line-edge or linewidth roughness involves uncertainty, like all measurements, and an estimate of that uncertainty should be reported whenever a roughness measurement is reported. However, roughness measurement uncertainty estimates are complicated by the correlations along the length of the rough feature. As a result, roughness measu...
Article
Full-text available
Article
Measuring the frequency response of roughness is necessary in many applications, leading to the common use of the power spectral density (PSD) of the roughness. But biases and random uncertainties in the PSD have led some to explore the use of the autocovariance function (ACF) and the height–height covariance function (HHCF) instead. These function...
Conference Paper
Optical Proximity Correction (OPC) has continually improved in accuracy over the years by adding more physically based models. Here, we further extend OPC modeling by adding the Analytical Linescan Model (ALM) to account for systematic biases in CD-SEM metrology. The ALM was added to a conventional OPC model calibration flow and the accuracy of the...
Article
Full-text available
Article
Lack of progress in reducing linewidth roughness of lithographic features has led to investigations of the use of post-lithography process smoothing techniques. But it remains unclear whether such postprocessing will sufficiently reduce the detrimental effects of feature roughness. Thus, there is a need to understand the efficacy of post-processing...
Article
Full-text available
All parties in the peer-review process (authors, editors, and reviewers) must work in an environment of mutual trust and cooperation. Honesty and integrity are of course required in all aspects of the process. Additionally, each participant in the peer-review process has specific responsibilities that must be fulfilled One needs to provide a transp...
Article
A half century ago, a young engineer named Gordon E. Moore took a look at his fledgling industry and predicted big things to come in the decade ahead. In a four-page article in the trade magazine Electronics, he foresaw a future with home computers, mobile phones, and automatic control systems for cars. All these wonders, he wrote, would be driven...
Article
Critical dimension scanning electron microscope (CD-SEM) metrology has long used empirical approaches to determine edge locations. While such solutions are very flexible, physics-based models offer the potential for improved accuracy and precision for specific applications. Here, Monte Carlo simulation is used to generate theoretical linescans from...
Article
Full-text available
From the beginning of the scientific revolution in the 16th and 17th centuries, scientific discoveries were mostly communicated in two basic forms: self-published books and pamphlets, and personal letters. The success of the Philosophical Transactions inspired the birth of many other journals, most of which experienced significantly less longevity....
Article
Full-text available
Writing is inherently a creative process. That would seem a good fit for the science researcher, where creativity coupled with critical thinking is the key to success. There are two main advantages of following the IMRaD structure: it makes it easier on the writer to organize the content of the paper, and it makes it easier on the reader to opportu...
Conference Paper
Full-text available
Presentation Outline: Super-resolution with Multi-wavelength lithography (MWL) has been demonstrated. Principles: Improve resolution by trimming an actinic image using a deactivating λ Resist Background: For non-SC applications resolution to 9 nm using visible λ Semiconductor Lithography Possible Tool Solutions: Modified scanner, Interference lith...
Conference Paper
Moore’s Law, the idea that every two years or so chips double in complexity and the cost of a transistor is always in decline, has been the foundation of the semiconductor industry for nearly 50 years. The main technical force behind Moore’s Law has been lithography scaling: shrinking of lithographic features at a rate faster than the increase in f...
Article
Full-text available
Conference Paper
Line-edge roughness (LER) and linewidth roughness (LWR) in lithography are best characterized by the roughness power spectrum density (PSD), or similar measures of roughness frequency and correlation. The PSD is generally thought to be described well by three parameters: standard deviation, correlation length, and roughness exponent. The next step...
Article
For a feature of finite length, linewidth roughness leads to variations in the mean feature width. Typically, numerical simulations are used to explore this relationship. An analytical approach is used. Starting with a common expression for the power spectral density, an analytical expression relating critical dimension uniformity to linewidth roug...
Article
Full-text available
The article outlines the methods using which researchers can write good scientific papers. There are two aspects of quality relevant to journal publications: the quality of the work being reported, and the quality of the reporting. With the exception of review papers and tutorials, a manuscript must contain something new to be worthy of publication...
Article
Full-text available
Chris Mack, Editor-in-Chief, Journal of Micro/Nanolithography, MEMS, and MOEMS, suggests some useful points for writing a good scientific paper. According to him, figures are an extremely important part of any scientific publication, and they should be properly depicted with the help of a graph. As with every aspect of science writing, integrity pl...
Article
A lattice-type Monte Carlo-based mesoscale model and simulation of the lithography process have been adapted to study the insoluble particle generation that arises from statistically improbable events. These events occur when there is a connected pathway of soluble material that envelops a volume of insoluble material due to fluctuations in the dep...
Article
The mechanism of extreme ultraviolet resist exposure is still in debate, with various competing mechanisms proposed. Here, three different continuum exposure models and two stochastic exposure models are compared, using predictions of acid concentration and yield as a function of dose and photoacid generator (PAG) loading. The models studied are a...
Article
Full-text available
Higher resolution demands for semiconductor lithography may be fulfilled by higher numerical aperture (NA) systems. However, NAs more than the photoresist refractive index (~1.7) cause surface confinement of the image. In this paper we describe how evanescent wave coupling to effective gain medium surface states beneath the imaging layer can counte...
Conference Paper
Measurement of the power spectral density (PSD) of a rough surface or feature involves large random and systematic errors. While random errors can be reduced by averaging together many PSDs, systematic errors can be reduced only by carefully studying and understanding the sources of these systematic errors. Using both analytical expressions and num...
Article
Numerical methods of generating rough edges, surfaces, and volumes for subsequent simulations are commonly employed, but result in data with a variance that is downward biased from the desired value. Thus, it is highly desirable to quantify and to minimize this bias. Here, the degree of bias is determined through analytical derivations and numerica...
Article
Full-text available
Chris Mack, Editor-in-Chief, Journal of Micro/Nanolithography, MEMS, and MOEMS, suggests some useful tips on writing a good scientific paper. An author of a scientific paper is anyone who has made a creative contribution to the words or ideas being presented that are claimed to be novel. Before publication, authors are responsible for their ethical...
Article
Characterization of a stochastic process in lithography, giving rise to photoresist line-edge roughness (LER), requires elucidation of the power spectral density (PSD) for that process. Thus, any analytical model for LER requires an analytical model for the PSD. Using a previously derived formulation for the reaction-diffusion autocorrelation funct...
Article
Full-text available
Higher resolution demands for semiconductor lithography may be fulfilled by higher numerical aperture (NA) systems. However, NAs more than the photoresist refractive index (~1.7) cause surface confinement of the image. In this letter we describe how evanescent wave coupling to effective gain medium surface states beneath the imaging layer can count...
Article
In the last year our Solid Immersion Lloyd's Mirror Interference Lithography (SILMIL) system has proved to be a successful tool for evanescent interferometric lithography (EIL). The initial goal was to use SILMIL in conjunction with the surface plasmon polariton (SPP) surface states at the resist-metal interface. Through this resonance, we aimed to...
Article
Full-text available
BACKGROUND: Previous simulation work has shown that uncorrelated Gaussian randomness in the development rate produces surface roughness in a resist that obeys Family-Viscek scaling in the KPZ universality class. However, more rigorous mesoscale simulations produce anomalous scaling. METHODS: Using a stochastic resist simulator, the dynamical roughn...
Article
Development rate can be defined microscopically (the development rate at a point) or macroscopically (the propagation rate of an average resist height). In the presence of stochastic noise, these two rates will be different. Using a stochastic resist simulator, the propagation rate of a resist surface is calculated in the presence of stochastic var...

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Projects (3)
Project
Stochastic effects leading to surface and edge roughness of lithographically printed features; the metrology and analysis of roughness