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7TH ANNUAL CONF ON INTEGRATED CIRCUIT METROLOGY, INSPECTION, AND PROCESS CONTROL

作者： ARNOLD, WH BAROUCH, E HOLLERBACH, U ORSZAG, SA Advanced Micro Devices Inc. Integrated Technology Division MS 79 901 Thompson Place Sunnyvale 94088-3453 CA United States Program in Applied and Computational Mathematics Princeton University Princeton 08544-1000 NJ United States

ISBN: (纸本)0819411604

As the depth of focus of optical steppers grows smaller, it becomesmore important to determine the position of best focus accurately andquickly. This paper describes the use of phase-shifted mask technologyto form a focus vernier: a phase pattern on the stepper reticle which,when imaged in resist, cangive both the magnitude and the direction ofthe focus error. In this, the focus vernier structure is analogous to3overlay verniers. Thus the determination of focus error can be treatedas an alignment problem in the z-axis. This technique is an improvementon previous schemes for the determination of best focus from resistimages as it can indicate both the magnitude of the error and itsdirection in a single exposure. © 1993 Proceedings of SPIE - The International Society for Optical Engineering. All rights reserved.

关键词： Errors

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Evaluation of depth‐of‐focus in photolithography at 193 and 248 nm for feature sizes of 0.25 μm and below

Journal of Vacuum Science & Technology B: Microelectronics a...

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Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena 1993年第6期11卷 2720-2724页

作者： M. Rothschild S. P. Doran E. Barouch U. Hollerbach S. A. Orszag Lincoln Laboratory Massachusetts Institute of Technology Lexington Massachusetts 02173‐9108 Program of Applied and Computational Mathematics Princeton University Princeton New Jersey 08544

The aerial image of alternative exposure systems was calculated in order to determine process latitude in photolithography at 0.25 μm and below. A fast software package was used for both simple and complex mask patterns. The depth‐of‐focus (DOF) was obtained with the aid of exposure–defocus plots at 193 and 248 nm. The numerical aperture and degree of spatial coherence were varied over a wide range. The effects of annular illumination were also studied. It was shown that for most geometries the DOF at 193 nm exceeds that of 248‐nm systems. Only for equal lines and spaces does a 248‐nm tool with annular illumination possess a DOF comparable to that of a conventionally illuminated 193‐nm system.

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Modeling of multilayer ion etching processes

Journal of Vacuum Science & Technology B: Microelectronics a...

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Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena 1993年第4期11卷 1310-1313页

作者： S. J. Sherwin E. Barouch G. E. Karniadakis S. A. Orszag Department of Mechanical and Aerospace Engineering Princeton University Princeton New Jersey 08540 Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08540

Numerical simulation is used to model ion etching in trilayer lithography. The simulations are capable of capturing the evolution of the boundary between two materials as well as the physically observed phonemena reactive ion etching lag and undercutting. Numerical results are compared with experimental data and a good agreement is found except close to the material interface where the slope of the surface is large. This error is attributed to a purely energy dependent yield used in the simulations.

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Benchmark Tests of Principal Fissile Nuclide Data in JENDL-3 with Simple Fast Critical Assemblies

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Journal of Nuclear Science and Technology 1993年第11期30卷 1087页

作者： TIAN, Dongfeng HASEGAWA, Akira NAKAGAWA, Tsuneo KIKUCHI, Yasuyuki Nuclear Data Center Department of PhysicsTokai Research EstablishmentJapan Atomic Energy Research Institute A visiting scientist through STA Scientist Exchange Program from Institute of Applied Physics and Computational Mathematics

A series of benchmark tests was made to check the neutron nuclear data of main fissile nuclides (239Pu, 236U and 233U) of JENDL-3 for fast reactors. A total of nine critical assemblies were analyzed. They are assemblies of single material, high enrichment and simple geometry with small volume and therefore suitable for nuclear data testing. Criticality calculation was made by ANISN with S16P5 using the VITAMIN-J 175-energy-group. Discussions are made on ken, spectral indices at core center and leakage spectra. From the study, a problem was pointed out relating to the interpolation of secondary-neutron energy distributions for threshold reactions near the threshold energy point adopted in the original JENDL-3 and its remedy was proposed. By the benchmark tests of thus revised JENDL-3 (JENDL-3.1), it was shown that integral experiments for 239Pu and 235U cores were reproduced quite satisfactorily. On the contrary, it was revealed that large deviations for 233U cores from the experiment were due to uncertainties of the fission spectrum and the inelastic scattering cross sections, In the present work, sensitivity of "a" parameter (level density parameter) of Madland-Nix's fission spectrum formula to the integral data was extensively studied. Some recommendations are made to improve JENDL-3.1.

关键词： JENDL-3 fast reactors benchmarks neutrons nuclear data cross section plutonium-239 uranium-235 uranium-233 Madland-Nix's fission spectra k eff spectral index leakage spectra accuracy

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THE CALLING(SM) NETWORK - A GLOBAL WIRELESS COMMUNICATION-SYSTEM

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第1期12卷 45-61页

作者： TUCK, EF PATTERSON, DP STUART, JR LAWRENCE, MH Calling Communications Corporation. 1900 West Garvey Ave South. Suite 200 West Covina CA 91790 USA. Chairman of Calling Communications Corporation. He is also the Managing Director of Kinship Venture Management Inc. the general partner of Kinship Partners 11 and a General Partner of Boundary the general partner of The Boundary Fund. As a venture capitalist he has founded or participated in founding several telecommunications companies including Calling Communications Corporation Magellan Systems Corporation manufactures of Global Positioning System receivers Applied Digital Access manufacturer of DS-3 test access and network performance monitoring equipment Endgate Technology Corporation specialists in satellite phased array antennas and Poynting Systems Corporation. now a division of Reliance Corporation manufacturers of fibre optic transport equipment. He was a founder of Kebby Microwave Corporation where he invented the first solid-state. frequency-modulated commercial microwave link system. The company was acquired by ITT Corporation where he rose to the position of V.P. and Technical Director of ITT North America Telecommunications Inc. Subsequently he was V.P. of Marketing and Engineering at American Telecommunications Inc. (ATC). He was founding Director of American Telecom Inc. a joint venture between ATC and Fujitsu and has served on more than 20 boards of directors including those of three public companies. He has authored articles on microwave engineering and telephone signalling and was a contributor to Reference Data For Radio Engineers. He is a graduate of the University of Missouri at Rolla where he was later awarded an honorary Professional degree and serves on its Academy of Electrical Engineering. Mr Tuck is a Senior Member of the IEEE a Fellow of the Institution of Engineers (Australia) a Professional Member of the AIAA and a registered professional engineer in three states. More than 25 years of experience in the telecommunications industry where he has been responsibl

There is a very large demand for basic telephone service in developing nations, and remote parts of industrialized nations, which cannot be met by conventional wireline and cellular systems. This is the world's largest unserved market. We describe a system which uses recent advances in active phased arrays, fast-packet switching technology, adaptive routeing, and light spacecraft technology, in part based on the work of the Jet Propulsion Laboratory and on recently-declassified work done on the Strategic Defense Initiative, to make it possible to address this market with a global telephone network based on a large low-Earth-orbit constellation of identical satellites. A telephone utility can use such a network to provide the same modern basic and enhanced telephone services offered by telephone utilities in the urban centres of fully-industrialized nations. Economies of scale permit capital and operating costs per subscriber low enough to provide a service to all subscribers, regardless of location, at prices comparable to the same services in urban areas of industrialized nations, while generating operating profits great enough to attract the capital needed for its construction. The bandwidth needed to support the capacity needed to gain these economies of scale requires that the system use K(alpha)-band frequencies. This choice of frequencies places unusual constraints on the network design, and in particular forces the use of a large number of satellites. Global demand for basic and enhanced telephone service is great enough to support at least three networks of the size described herein. The volume of advanced components, and services such as launch services, required to construct and replace these networks is sufficient to propel certain industries to market leadership positions in the early 21st Century.

关键词： LOW EARTH ORBIT SATELLITE COMMUNICATIONS FAST PACKET SWITCHING EARTH FIXED CELLS ADAPTIVE ROUTEING LIGHT SPACECRAFT K(A) BAND PHASED-ARRAY ANTENNAS

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Stochastic Treatment of Adsorbate Local-Potential Effects on Surface-Ion Neutralization

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Physical Review Letters 1993年第24期71卷 4075-4075页

作者： Zoran L. Mišković Sydney G. Davison Frank O. Goodman Department of Applied Mathematics University of Waterloo Waterloo Ont. N2L 3G1 Canada Institute of Nuclear Sciences-Vinča Belgrade Department of Physics University of Waterloo Guelph-Waterloo Program for Graduate Work in Physics

The influence of a laterally inhomogeneous electrostatic potential of an adsorbate-covered surface on the resonant charge transfer in ion-surface scattering is investigated by means of the time-dependent Anderson-Newns Hamiltonian. The adsorbate-induced random modulation of the projectile orbital energy level is treated as a stochastic process, and its role in the charge transfer is evaluated analytically, in the Gaussian-process approximation, for low projectile speeds and low surface coverage by alkali atoms.

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STATIONARY PREMIXED FLAMES IN A DUAL-SOURCE SYSTEM

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COMBUSTION AND FLAME 1992年第1期91卷 99-105页

作者： BREWSTER, ME Program in Applied Mathematics University of Colorado Boulder Colorado 80309-0526 USA

Stationary premixed flames in dual-source flow are considered. The significant features of the dual-source system are that the sources are of finite strength, and that a stagnation point is located between the sources. A new mathematical model for front propagation and advection is introduced that tracks the front along streamlines. The equations for the stationary fronts of the dual-source system are solved numerically. The assumption of constant-density potential flow is made to simplify the problem and to illustrate the effects of the geometry alone. It is shown that for sufficiently slow burning velocity (or equivalently, small source separation), three stationary states exist for closed, free flames, but one of them is unstable. In addition, several types of burner-attached flames are observed. Quasi-stationary evolution of a closed, free flame exhibits a change of topology and hysteresis. Nonclosed flames are predicted if local extinction due to flow strain is allowed.

关键词： Combustion

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A SIZE-STRUCTURED MODEL FOR CANNIBALISM

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THEORETICAL POPULATION BIOLOGY 1992年第3期42卷 347-361页

作者： CUSHING, JM Department of Mathematics Interdisciplinary Program in Applied Mathematics Building 89 University of Arizona Tucson Arizona 85721 USA

A size-structured model for the dynamics of a cannibalistic population is derived under the assumption that cannibals (successfully) attack only smaller bodied victims, as is generally the case in the biological world. In addition to the resulting size-dependent death rate, the model incorporates the positive feedback mechanism resulting from the added resource energy obtained by the cannibal from the consumption of the victim. From the nonlinear partial integro-differential equation model, it is shown how to obtain a complete analysis of the global dynamics of the total population biomass. This analysis yields many dynamical features that have been attributed to cannibalism in the literature, including density self-regulation, a “life-boat strategy” phenomenon by which a population avoids extinction by practicing cannibalism under circumstances when it would otherwise go extinct, and multiple stable positive equilibrium states and hysteresis.

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A DISCRETE MODEL FOR COMPETING STAGE-STRUCTURED SPECIES

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THEORETICAL POPULATION BIOLOGY 1992年第3期41卷 372-387页

作者： CUSHING, JM Department of Mathematics Interdisciplinary Program in Applied Mathematics Building 89 University of Arizona Tucson Arizona 85721 USA

This paper deals with the problem of relating physiological properties of individual organisms to the dynamics at the total population level. A general nonlinear matrix difference equation is described which accounts for the dynamics of stage-structured populations under the assumption that individuals in the populations can be placed into well defined descriptive stages. Density feedback is modeled through an assumption that (stage-specific) fertilities and transitions are proportional to a resource uptake functional which is dependent upon a total weighted population size. It is shown how, if stage-specific differences in mortality are insignificant compared to stage-specific differences in fertility and inter-stage transitions, a nonlinear version of the strong ergodic theorem of demography mathematically separates the population level dynamics from the dynamics of the stage distribution vector, which is shown to stabilize independently of the population level dynamics. The nonlinear dynamics at the population level are governed by a key parameter π that encapsulates the stage-specific parameters and thereby affords a means by which population level dynamics can be linked to properties of individual organisms. The method is applied to a community of stagestructured populations competing for a common limiting resource, and it is seen how the parameter π determines the competitively superior species. An example of size structured competitors illustrates how the method can relate the competitive success of a species to such size-specific properties as resource conversion efficiencies and allocation fractions for individual growth and reproduction, largest adult body size, and size at birth and maturation.

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FUZZY MOLECULAR-SURFACES

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JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS 1992年第4期9卷 759-768页

作者： AGISHTEIN, ME Program in Applied and Computational Mathematics Fine Hall Princeton University NJ 08544-1000.

Surface area of a macromolecule, accessible to a solvent, is defined and calculated, taking into account the probabilistic character of atomic positions due to the high frequency atomic vibrations. For a given a space point, we consider a probability of the event, that this point is covered by a macromolecule. A volume is defined as a space integral of this probability field. The envelope, accessible to a solvent molecule center, becomes fuzzy, existing only in a probabilistic sense. The accessible area is defined as a derivative of the envelope volume with respect to the probe size. The accessible area thus defined has the advantage of being an analytic function of atomic coordinates and allows for an arbitrary (not necessarily spherical) probe geometry. Space integration is performed on a rectangular grid, using a third order Runge-Kutta integration scheme and the analytical subgrid averaging.

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