bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Analytic Approach to the Radiation Fields of Tubular Halogen Lamp Arrangements in RTP Reactor Blocks
Authors: Theiler Thomas 
Published: April 2011

AbstractStarting with basic physical radiation principles and with Beers law formulas for the radiation characteristics of arrays of pointlike radiation sources and tubular halogen lamps are analytically derived. Different arrangements of tubular halogen lamps are considered and compared with each other. Homogeneity criteria are worked out and it is demonstrated that the minimum homogeneity distance between a plane in which all filaments are arranged parallel to each other, and an object depends only on the distance between two neighbouring filaments and thus can be given by a simple number. Interesting aspects for RTP equipment manufacturers as well as for users are demonstrated by comparing different lamp arrangements with each other: In crossed lamp fields latticelike inhomogeneity knots arise in the object plane at points where the lamp filaments of the upper and the lower lamp plane cross. If the filaments are arranged parallel to each other in two filament planes, very homogeneous results are obtained when the filaments of the two planes interlace.
Application of a Neural Manufacturing Concept to Process Modeling, Monitoring and Control
Authors: Fu Chi Yung , Petrich Loren , Law Benjamin 
Published: April 2011

AbstractThe cost of a fabrication line, such as one in a semiconductor house, has increased dramatically over the years, and it is possibly already past the point that some new start-up company can have sufficient capital to build a new fabrication line. Such capital-intensive manufacturing needs better utilization of resources and management of equipment to maximize its productivity. In order to maximize the return from such a capital-intensive manufacturing line, we need to work on the following: 1) increasing the yield, 2) enhancing the flexibility of the fabrication line, 3) improving quality, and finally 4) minimizing the down time of the processing equipment. Because of the significant advances now made in the fields of artificial neural networks, fuzzy logic, machine learning and genetic algorithms, we advocate the use of these new tools in manufacturing. We term the applications to manufacturing of these and other such tools that mimic human intelligence neural manufacturing. This paper describes the effort at the Lawrence Livermore National Laboratory (LLNL) [1] to use artificial neural networks to address certain semiconductor process modeling, monitoring and control questions.
Design-Coupled Manufacturing
Authors: Lemnios Zachary J. 
Published: April 2011

AbstractA new approach to semiconductor manufacturing is necessary to decouple end product cost from factory volume. The economy of scale model for manufacturing semiconductor integrated circuits is leading to factories that cost in excess of $1 billion and with costs anticipated to increase nonlinearly. Perhaps of greater concern is that process development and integration costs are of the same magnitude. The Advanced Research Projects Agency (ARPA) has funded several stand-alone research programs to explore new ways of designing and fabricating leading-edge semiconductors. The next steps are to tightly couple design and manufacturing through powerful new frameworks and embedded intelligence with tools. This new manufacturing capability based on flexible, intelligent equipment coupled to a powerful design framework could lead to a leading-edge manufacturing capability, but at a fraction of the cost of a conventional factory. Furthermore, this manufacturing model supports innovation and could lead to a new generation of ICs and systems. The key elements necessary to enable this new semiconductor fabrication environment is described.
Surface-Topography Simulations of Ionized Sputter Metal Deposition
Authors: Hamaguchi S. , Rossnagel S.M. 
Published: April 2011

ABSTRACTNumerical simulations are used to predict microscopic topography of deposited metal films in ionized magnetron sputter deposition experiments. The simulation takes into account ionized and neutral fluxes as deposition material sources and re–sputtering and re–deposition of the deposited material due to the ion bombardment. The shock-tracking algorithm is used to advance the moving surface boundary. Applications of this deposition technique include lining and filling of trenches, vias and dual damascene.
Simulation of Film Growth Contour in a Narrow Deep Trench and Film Crystallinity in LPCVD Process
Authors: Hwang Gyeong Soon , Shin Chee Burm , Moon Sang Heup 
Published: April 2011

ABSTRACTDeposition of a thin film in the LPCVD process has been simulated by a Monte–Carlo method based on a simple model taking into account the desorption, the surface reaction, and the surface migration of the film precursor. The model has been used for the simulation of the film profile obtained in a narrow and deep trench and of the film crystallinity on a flat surface. The simulation results describe successfully those obtained by experiments under various process conditions.
Simulation of the Nucleation and Growth of Si Grains Inside Au Thin Films
Authors: Pasa A. A. , Neugebauer M. , Losch W. , Bauer G. H. 
Published: April 2011

ABSTRACTThe Si crystallization process induced by the presence of a gold thin film was computer simulated using a random resistor network and concepts of the percolation theory. The model considers initially a pure Au resistor network. The random appearance of Si nuclei corresponds to a high local variation of the resistance value. The crystallization process was simulated step-by-step and parameters as nucleation rate and growth rate were tested. Considering an interface limited reaction process, the simulated results are in good agreement with experimentally obtained in-situ electrical measurements and scanning electron microscopy micrographies.
Monte Carlo Simulation of Dislocation-Nucleated Etching of Silicon {111} Surfaces
Authors: Woodraska Donald L. , Lacosse Jason , Jaszczak John A. 
Published: April 2011

ABSTRACTWe investigate equilibrium properties and thermal etching of the {111} surfaces of silicon, both with and without perpendicular intersecting dislocations, using Monte Carlo computer simulation. A modified solid-on-solid (SOS) approach is employed which realizes the correct diamond-cubic (DC) crystal structure. Nearest-neighbor interactions are incorporated to model the bonding, while the effects of a dislocation are incorporated by the addition of an energy field modeled as a core region and an elastic strained region. Dislocations are seen to nucleate the etching process and result in the formation of etch pits. Etch rates and etch-pit morphologies are investigated as a function of the chemical potential driving force for etching, the temperature, and the energy parameters used to model the dislocation.
Transient and Spatial Radiative Properties of Patterned Wafers during Rapid Thermal Processing
Authors: Wong Peter Y. , Miaoulis Ioannis N. , Madras Cynthia G. 
Published: April 2011

ABSTRACTTemperature measurements and processing uniformity continue to be major issues in Rapid Thermal Processing. Spatial and temporal variations in thermal radiative properties of the wafer surface are sources of non-uniformities and dynamic variations. These effects are due to changes in spectral distribution (wafer or heat source), oxidation, epitaxy, silicidation, and other microstructural transformations. Additionally, other variations are induced by the underlying (before processing) and developing (during processing) patterns on the wafer. Numerical simulations of Co silicidation that account for these factors are conducted to determine the radiative properties, heat transfer dynamics, and resultant processing uniformity.
Concurrent Design of an RTP Chamber and Advanced Control System
Authors: Spenc Paul , Schaper Charles , Kermant Ahmad 
Published: April 2011

ABSTRACTA concurrent-engineering approach is applied to the development of an axisymmetric rapidthermal-processing (RTP) reactor and its associated temperature controller. Using a detailed finiteelement thermal model as a surrogate for actual hardware, we have developed and tested a multi-input multi-output (MIMO) controller. Closed-loop simulations are performed by linking the control algorithm with the finite-element code. Simulations show that good temperature uniformity is maintained on the wafer during both steady and transient conditions. A numerical study shows the effect of ramp rate, feedback gain, sensor placement, and wafer-emissivity patterns on system performance.
Fundamental Mechanisms for Hg Vacancy and Interstitial Modeling in Mercury Cadmium Telluride
Authors: Holander S.L. , Robinson H.G. , Helms C.R. 
Published: April 2011

ABSTRACTDue to the large concentration of electrically active defects in Hg1-xCdxTe, it is important to properly account for them when designing fabrication processes for infrared focal plane arrays (IRFPAs). Stanford University's Mercury Cadmium Telluride Process Simulator, SUMerCad, is being developed to simulate the interaction of native defects and dopants in Hg0.8Cd0.2Te in order to accurately model various processing techniques. Non-linear coupled differential equations are used to model the physics of the diffusion mechanisms, rather than extrapolating the diffusion profiles from experimental data. The fundamental constants for the point defects were obtained by exercising the simulator over the various parameter spaces and comparing the results to experimental work and best principle calculations. The methodologies used, point defect mechanisms modeled, and parameters determined are discussed.
Experimental Results and Modeling of the Codiffusion of Donors and Acceptors in Si
Authors: Solmi S. , Valmorri S. 
Published: April 2011

ABSTRACTA model based on ion pairing for the simulation of donor and acceptor codiffusion in silicon is presented. The proposed model allows us to obtain a good agreement with the experimental profiles over a wide range of diffusion conditions, specially at high concentrations where the standard process simulator codes give results strongly inaccurate. Comparison of the simulations with new and literature codiffusion profiles is provided.
Measurement and Modeling of Intrinsic Stresses in CVD W Lines
Authors: Lee Jin , Ma Qing , Marieb Thomas , Mack Anne S. , Fujimoto Harry , Flinn Paul , Woolery Bruce , Keys Linda 
Published: April 2011

AbstractWe have studied stress states in chemical vapor deposited (CVD) tungsten (W) for both blanket films and lines, to understand better the mechanical implications of intrinsic stress for interconnection structures. Since W has a low mobility at its deposition temperature, a very large intrinsic stress develops during deposition. Intrinsic strains in blanket W films were measured with an X-ray technique. The measured strains correspond to a biaxial tensile stress of the order of 1 GPa. This result was used to provide an initial strain input in a finite element calculation to obtain intrinsic stress states in W lines. SEM observation of cross sections of the metal lines enabled us to determine the growth pattern of the W, and infer the boundary conditions during growth. Finite Element Method (FEM) calculations of the room temperature stress in the lines, including both intrinsic and thermal components, are in good agreement with X-ray determinations.
Time-Dependent Dielectric Breakdown in Thin Intrinsic SiO2 Films
Authors: Suehle J. S. , Chaparala P. 
Published: April 2011

AbstractTime-Dependent Dielectric Breakdown studies were performed on 6.5-, 9-, 15-, 20-, and 22.5-nm thick SiO2 films over a wide range of stress temperatures and electric fields. Very high temperatures (400 °C) were used to accelerate breakdown so that stress tests could be performed at low electric fields close to those used for device operating conditions. The results indicate that the dependence of TDDB on electric field and temperature is different from that reported in earlier studies. Specifically, the electric-field-acceleration parameter is independent of temperature and the thermal activation energy was determined to be between 0.7 and 0.9 eV for stress fields below 7.0 MV/cm.Failure distributions of high-quality current-generation oxide films are shown to be of single mode and have dispersions that are not sensitive to stress electric field or temperature, unlike distributions observed for oxides examined in earlier studies. These results have implications on the choice of the correct physical model to describe TDDB in thin films. The data also demonstrate for the first time the reliability of silicon dioxide films at very high temperatures.
Effect of Electric ARC Plasma Jet Treatment on Mos Structure Reliability
Authors: Maslovsky V. M. , Pavlov G. Ya. 
Published: April 2011

AbstractThe effect of electric arc plasma jet treatment (APJT) on MOS structure reliability has been investigated. Si/SiO2/Si*/Al structures have been studied using the technique of constant current charge to breakdown before and after APJT. The study showed that APJT can improve MOS structure reliability: constant current charge to breakdown Qbd increased to more than 5 C·cm-2 and breakdown field Ebd increased to more than 20 MV/cm. This result was attributed to a structural modification of SiO2 and its interfaces as a result of APJT. Evidence for these structural changes is the appearance of additional SiO2 IR absorption peak which was observed by us.
Modeling of the Structure and Reliability of Near-Bamboo Interconnects
Authors: Thompson C.V. , Joo Y.-C. , Knowlton B.D. 
Published: April 2011

AbstractWhen interconnect feature sizes (e.g., widths) and grain sizes are comparable, their average electromigration-lifetime increases. However, reliability increase occurs for a population of lines only if microstructural weak links, such as polygranular clusters, become unlikely throughout the population. Lifetime statistics and grain structure statistics are linked in a way which must be understood in order to take advantage of lifetime improvements through line-width-dependent and line-length-dependent current density limits. An analytic model has been developed which allows calculation of the polygranular cluster length distribution as a function of line width, line length and current density, given continuous-film median grain sizes and grain size deviations. A simple analytic model for the effect of post-patterning anneals on polygranular cluster length distributions is also presented. These models are shown to be consistent with detailed computer simulations of grain structures and grain structure evolution in interconnects. Improved grain structure models will enable less-conservative integrated circuit design practice, allowing design of higher performance circuits.
A Comparative Study on the Titanium Nitride (TiN) as a Diffusion Barrier Between Al/Si and Cu/Si: Failure Mechanism and Effect of “Stuffing”
Authors: Park Ki-Chul , Kim Ki-Bum 
Published: April 2011

AbstractThe diffusion barrier properties of 100-nm-thick TiN films, both as-deposited and "stuffed", were investigated in both Al/TiN/Si and Cu/TiN/Si metallization systems. In Al/TiN/Si systems, the TiN barrier fails by the formation of both Al spikes and Si pits in the Si substrate. However, in Cu/TiN/Si systems, the failure of TiN diffusion barriers occurs by the predominant diffusion of Cu into the Si substrate, which forms dislocations along the projection of Si {111} plane and precipitates (presumably Cu-silicides) around the dislocation. In Al/TiN/Si systems, it is shown that the diffusion barrier property of TiN is significantly enhanced by "stuffing" in N2 ambient prior to Al deposition. However, in Cu/TiN/Si systems, it is found that the "stuffing" of TiN does not improve the diffusion barrier property as it does in Al/TiN/Si systems.
The Effects of Processing on the Microstructure of Copper Thin Films on Tantalum Barrier Layers
Authors: Zielinski E.M. , Vinci R.P. , Bravman J.C. 
Published: April 2011

abstractPreferred crystallographic orientation and grain size distribution were characterized as a function of processing for sputtered Cu films on Ta underlayers. The Ta barrier layer was deposited at two temperatures, 30 and 100 °C. Cu was deposited at 30, 150 and 250 °C on the 30 °C Ta, and at 100, 150, 200 and 250 °C on the 100 °C Ta. In the first set of samples, with increasing deposition temperature, the Cu (111) fiber texture grew weaker and the volume fraction of randomly oriented grains increased from 0.23 to 0.74. In contrast, for the films deposited on the 100 °C Ta, with increasing deposition temperature, Cu (111) fiber texture strengthened and the fractions of randomly oriented and twinned grains decreased. Grain size was lognormally distributed in all samples and varied approximately parabolically with deposition temperature. At a given deposition temperature, median grain size in the Cu was larger in the films deposited on the 100 °C Ta. These results will be related to the microstructure of the Ta underlayers. Cu microstructure on the 100 °C Ta is shown to be influenced by textural inheritance from the Ta underlayer. Microstructure of the Cu on 30 °C Ta is discussed in terms of trace contaminants.
Surface Passivation of Cu by Annealing Cu/Al Multilayer Films
Authors: Wang W. , Lanford W.A. , Murarka S.P. 
Published: April 2011

AbstractSurface passivation of Cu by annealing Cu/Al multilayer films (Cu/Al/Cu/Al/Cu) on SiO2 has been demonstrated. Cu/Al multilayer films were annealed from 300°C to 500°C. The buried Al is transported to the Cu surface during annealing, forming A12O3 at the exposed surface. The Cu in annealed Cu/Al multilayer films shows no oxidation when heated in air at 300°C for 24 hrs. The electrical resistivity of these films is 2.3 μΩ cm.
A Highly Reliable Al Line with Controlled Texture and Grain Boundaries
Authors: Hasunuma M. , Toyoda H. , Kawanoue T. , Ito S. , Kaneko H. , Miyauchi M. 
Published: April 2011

AbstractIn order to clarify the relationship between Al line reliability and film microstructure, especially grain boundary structure and crystal texture, we have tested three kinds of highly textured Al lines, namely, single-crystal Al line, quasi-single-crystal Al line and hypertextured Al line, and two kinds of conventional Al lines deposited on TiN/Ti and on SiO2. Consequently, the empirical relation between the electromigration (EM) lifetime of Al line † and the (111) full width at half maximum (FWHM) value ω is described by † ∝ ω-2 [1]. This improvement of Al line reliability results from as following reasons; firstly, homogeneous microstructure and high activation energy of 1.28eV for the single-crystal Al line (ω=0.18°); secondly, sub-grain boundaries which consisted of dislocation arrays found in the quasi-single-crystal Al line (ω=0.26°) has turned out to be no more effective mass transport paths because dislocation lines are perpendicular to the direction of electron wind. Although there exist plural grain boundary diffusion paths in the newly developed hypertextured Al line (ω=0.5°) formed by using an amorphous Ta-Al underlayer {1], the vacancy flux along the line has been suppressed to the same order of magnitude of single crystal line. It has been clarified that the decrease of FWHM value has promoted the formation of sub-grain boundaries and low-angle boundaries with detailed orientation analysis of individual grains in the hypertextured film. The longer EM lifetime for the hypertextured Al line is considered to be due to the small grain boundary diffusivities for these stable grain boundaries, and this diffusivity reduction resulted in the suppression of void/hillock pair in the Al lines. These results have confirmed that controlling texture and/or grain boundary itself is a promising approach to develop reliable Al lines which withstand higher current densities required in future ULSIs.
Microtexture Measurements of Aluminum VLSI Metallization
Authors: Barr D.L. , Brown W.L. , Marcus M.A. , Ohring M. 
Published: April 2011

AbstractThe microtexture of thin film aluminum has been studied using Electron Backscatter Diffraction (EBSD). The results indicate that, while the overwhelming majority of polycrystallite grains have a <111> fiber texture with the < 111 > axis within -5° of the surface normal, 1-2 % of the grains deposited on SiO2 show large deviations off of this axis. The off-texture grains are typically much smaller than those that are <111> textured. These observations have been made for Al(Cu) films with several different Cu concentrations and for different substrate materials. The statistical distributions of the orientations in the different cases are presented. Electrical stressing of 0.8 um Al(0.5%Cu) lines resulted in elimination of the small number of grains with off-<l 11> orientation.
Quantitative Three-Dimensional Characterization of the Morphology of Stressed and Electromigrated Aluminum Lines
Authors: Ramseyer George O. , Beasock Joseph V. , Helbig Herbert F. , Walsh Lois H. 
Published: April 2011

AbstractThe volumes of slit, edge, erosion and erosion/slit voids in stressed and electromigrated aluminum conductor lines were quantitatively determined with low resolution standard and high resolution enhanced tips by atomic force microscopy. These three-dimensional results were compared to semiquantitative determinations of void volumes extrapolated from two-dimensional backscattered scanning electron microscopy area determinations of the passivated aluminum conductor. After the passivation was removed by plasma etching, void volumes were also determined from two-dimensional scanning electron microscopy micrographs. The volumes of the nearest hillocks on the anodic side of the voids were quantitatively determined by atomic force microscopy, and these hillock volumes were determined to be independent of the respective void volumes.
The Influence of Grain Structure on the Reliability of Narrow Al-Based Interconnects
Authors: Kang S.H. , Kim C. , Génin F.Y. , Morris J.W. 
Published: April 2011

AbstractThe work reported here concerns the effect of grain structure on electromigration failure in pure Al and Al-2wt.%Cu-lwt.%Si lines. The grain structures of fine lines were controlled by annealing after patterning to promote the formation of "bamboo" structures. Significant improvements in the median time to failure (MTF) and the deviation of the time to failure (DTF) were observed with the development of near-bamboo structures with polygranular-segment lengths shorter than ~ 5 μm. The most common failure sites are voids or slits across bamboo grains at the upstream ends of polygranular segments. The time-to-failure decreases with the polygranular segment length, and can be significantly enhanced by controlling the grain structure.
Electromigration Damage and Failure Distributions in Al-4wt.%Cu Interconnects
Authors: Shih W. C. , Greer A. L. 
Published: April 2011

AbstractUnpassivated 2.1μm and 1.1μm wide lines of Al-4wt.%Cu have been electromigration-stressed to failure under accelerated testing conditions (up to 300 °C and 2 x 1010 A m-2). The line resistance and microstructure and the development of electromigration damage are discontinuously recorded. Distributions of damage sites (hillocks and voids) along the line lengths are measured, and the evolution of the distributions with stressing time is followed. The distances between damage sites show a clear correlation with the grain structure. Damage and failure sites are concentrated near the end of the lines at which electrons enter.