bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapidly Evolving Disk–Jet Coupling during Re-brightenings in the Black Hole Transient MAXI J1535−571
Authors: Parikh A. S. , Russell T. D. , Wijnands R. , Miller-Jones J. C. A. , Sivakoff G. R. , Tetarenko A. J.
Published: June 2019

The main outburst of the candidate black hole low-mass X-ray binary (BH LMXB) MAXI J1535−571 ended in 2018 May and was followed by at least five episodes of re-brightenings. We have monitored this re-brightening phenomenon at X-ray and radio wavelengths using the Neil Gehrels Swift Observatory and Australia Telescope Compact Array, respectively. The first two re-brightenings exhibited a high peak X-ray luminosity (implying a high mass-accretion rate) and were observed to transition from the hard to the soft state. However, unlike the main outburst, these re-brightenings did not exhibit clear hysteresis. During the re-brightenings, when MAXI J1535−571 was in the hard state, we observed the brightening of a compact radio jet that was subsequently quenched when the source transitioned to a similar soft state, as was observed during the main outburst. We report on the first investigation of disk−jet coupling over multiple rapidly evolving re-brightenings in a BH LMXB. We find that the accretion flow properties and the accompanying compact jet evolve on a similarly rapid timescale of ∼days, rather than the typical value of ∼weeks as observed for most other BH LMXBs during their main outburst events.
Refugees as Migrant Settlers
Authors: Burgess Greg
Published: June 2019

Dans toute l’histoire des migrations en Australie, les réfugiés se distinguent à peine des immigrants ; ils ont plutôt été eux-mêmes des colons immigrants. Cependant, un récit humanitaire a émergé depuis la Seconde Guerre mondiale qui a caractérisé l’Australie comme une société généreuse et accueillante pour les réfugiés. Étant donné le passé migratoire de ce pays, cette caractéristique se révèle très ambiguë. L’article illustre le lien indélébile entre les histoires d’immigration et de réfugiés en Australie et la déconnexion entre cette histoire et le récit humanitaire souvent invoqué pour des raisons politiques.
L’accueil des étudiants réfugiés au XX e siècle
Authors: Tronchet Guillaume
Published: June 2019

En dehors de quelques études de cas, l’histoire mondiale des étudiants réfugiés reste à écrire. Bien moins étudiée que l’histoire des professeurs et des chercheurs en exil, cette question soulève de nombreux problèmes d’histoire politique, sociale et culturelle. Cet article est une première étape d’un projet de recherche en cours sur le sujet. Il propose quelques points de repère sur l’histoire mondiale des étudiants réfugiés et une analyse croisée de certaines tendances de cette longue histoire, afin d’expliquer comment la question des étudiants réfugiés fut d’abord un problème humanitaire et européen, avant de devenir un enjeu global et stratégique de concurrence entre États-nations au xx e  siècle.
Le réfugié de 1951 dans la continuité de l’asile politique du XIX e siècle
Authors: Tissier-Raffin Marion
Published: June 2019

Dans cet article, le concept de réfugié est étudié à partir de son application concrète par les juges de l’asile dans plusieurs États occidentaux. Nous montrons que le réfugié conventionnel, tout comme le destinataire du principe de non-extradition pour infractions politiques au xix e  siècle, correspond toujours à la figure du réfugié dissident. Le concept de réfugié s’enracinerait donc, en partie, dans une conception historique de l’asile politique telle qu’elle prévalait au xix e  siècle.
Esthétique de la nature ou esthétique environnementale ?
Authors: Schaeffer Jean-Marie
Published: June 2019

Après une longue période durant laquelle l’esthétique s’est exclusivement focalisée sur les arts, on assiste depuis quelques décennies à un renouveau d’intérêt pour le beau naturel. En choisissant comme repère la philosophie du xviii e siècle, l’objet de l’article est d’examiner dans quelle mesure l’actuelle esthétique de l’environnement est dans la filiation directe de la Critique de la faculté de juger . Pour Kant en effet, se rapporter à la nature dans la perspective d’une expérience esthétique revient à nous mettre à distance d’elle, alors que l’esthétique environnementale contemporaine s’inscrit dans le projet d’une esthétique non ségrégationniste où le souci écologique est prépondérant. En dépit de ressemblances de surface, ce qui les oppose est le plus significatif car le dualisme kantien est irréductible à la naturalisation de l’homme et de la culture.
De l’esthétique environnementale à la recherche création
Authors: Blanc Nathalie
Published: June 2019

Le présent article contribue à explorer les formes d’intermédiation esthétique qui rendent compte des emmêlements et des possibles métamorphoses nature-culture dans l’optique d’une esthétique environnementale. Nous proposons deux pistes en ce sens. La première piste de travail tend à conférer aux sciences humaines et sociales un rôle nouveau, celui de la médiation et de la traduction des subjectivités esthétiques à l’œuvre sur les territoires. La seconde fait de l’expérimentation esthétique et artistique en lien avec des environnements, le cœur d’une esthétique environnementale expérimentale que nous qualifions de recherche-création. Il s’agit de développer des pratiques de recherche esthétique et culturelle en relation avec des contextes situés, introduisant un nouveau regard sur le caractère relationnel des attachements multiples au territoire. Une collaboration art, science et société, entre COAL association engagée dans la promotion d’un art écologique et le LADYSS, un laboratoire de sciences humaines et sociales, vient accompagner la transition d’une Ferme Urbaine artistique en explorant, par entretiens, les récits-recettes des habitants du terroir urbain de Saint-Denis (qui compte 135 nationalités).
L’image-martyre. Réappropriations télévisuelles des vidéos d’amateur de l’attentat de Nice (2016)
Authors: Sapio Giuseppina
Published: June 2019

The article aims at analysing the role of amateur videos in the communication of information, with regard to the special editions of the international TV news broadcasted the day after the terroristic attack of July 14 th 2016 in Nice. Against a backdrop characterized by a systematic occultation of death, the videos contribute to the celebration of the survivors, by means of their sound dimension. Those “martyrs-images” have a witness value and help exorcise the violent death within media rituals such as news broadcasts.
La reforma de los mecanismos de control en la Real Hacienda de Nueva España (siglos XVI-XVIII)
Authors: Sánchez Santiró Ernest
Published: June 2019

El trabajo desarrolla una faceta de las medidas jurídico-administrativas desplegadas por la Monarquía hispánica sobre la Real Hacienda de Nueva España entre los siglos XVI y XVIII, a saber: los mecanismos de control, haciendo hincapié en la conformación de la red de oficinas del erario, la toma de decisiones sobre sus fondos, la vigilancia sobre sus oficiales y empleados y la generación de instrumentos y procesos administrativos.
Perfiles militares de la Tenencia de Gobernación santafesina en la era borbónica
Authors: Celeste Forconi María
Published: June 2019

La finalización de la guerra de Sucesión y la firma del tratado de Utrecht significó para los territorios del Río de la Plata un cambio en la posición geoestratégica en la disputa territorial. Este artículo intenta analizar la reorganización en sus equipamientos políticos tomando como mirador una jurisdicción subordinada de la gobernación de Buenos Aires, la ciudad de Santa Fe. A partir de los perfiles de los tenientes de gobernador se pretende observar la articulación entre dinámica local y reformas borbónicas de este proceso de reorganización de los dispositivos político-militares.
La inmigración y la crisis. Los polacos en el Buenos Aires de la década de los años treinta
Authors: Porada Katarzyna
Published: June 2019

El presente artículo se centra en la inmigración polaca radicada en la ciudad de Buenos Aires en la primera mitad de la década de los años treinta del siglo XX. Se estudiará aquí el impacto que la crisis económica mundial desatada en 1929 tuvo sobre este grupo particular y se analizarán las medidas tomadas por la colectividad para atenuar sus secuelas. Al mismo tiempo, se indagará sobre el porqué de la alta vulnerabilidad de los inmigrantes polacos en el contexto argentino.
1936. La pluma y la espada. Marinetti, Puccini y Ungaretti en el PEN Club argentino
Authors: De Aldama Ordóñez Celia
Published: June 2019

El artículo propone una lectura en clave política del desembarco en Buenos Aires de tres ilustres escritores —Filippo Tommaso Marinetti, Giuseppe Ungaretti y Mario Puccini— con motivo de la celebración del XIV Congreso Internacional del PEN Club argentino. Con el propósito de discernir si los intelectuales viajan como embajadores de las letras italianas o bien como propagandistas del régimen de Mussolini, se reconstruyen los respectivos calendarios de viaje, se rescatan de las notas de prensa de la época las conferencias dictadas durante las tournées y se recogen las impresiones vertidas sobre el país anfitrión en sus bitácoras de viaje.
Exploring the Effectiveness of Glog in Language Learning
Authors: Anitha Devi V
Published: June 2019

This paper reports the purpose of integrating Web 2.0 tool, Glogster in language learning tasks. Web 2.0 tools and digital blooms taxonomy have become prevalent in the English classroom with the ubiquitous use of smartphone, tabs and laptops in the language classroom. Certain details in this paper were presented in the Connecting Online (CO12) session in the year 2012. This paper also describes activities which would help in fostering creativity and autonomy in the teaching-learning process. Glogster is a web 2.0 tool which provides a platform for teachers and learners in creating and using glogs for language learning and other subjects. This tool provides a supportive platform for monitoring project based language learning activities. Having studied the use of the glog for language learning with the first batch of 54 students in 2009, in the following semesters 302 students were introduced to the glogging task. In total, 356 B.Tech students at VIT were introduced to web 2.0 tools for language learning tasks. They were introduced to the use of three Glogster tasks for synthesizing their real life and virtual language learning experiences in different semesters.
Sam Kok, presse et idée de nation chinoise aux Indes néerlandaises (fin XIXe-début du XXe s.)
Authors: Ge SONG
Published: June 2019

Sam Kok est le titre abrégé couramment utilisé en Indonésie pour désigner les traductions malaises du Sanguo yanyi 三国演义, l’un des plus remarquables romans historiques chinois. Cet article vise à examiner l’impact des Sam Kok aux Indes néerlandaises à la fin XIXe et au début du XXe siècle, selon deux axes : tout d’abord, au niveau des mentalités et de la vie quotidienne des Chinois peranakan ; ensuite, dans la presse, et plus particulièrement dans le Sin Po, dans lequel fut publiée une de deux premières traductions complètes (1910-1912). En analysant la coexistence entre modernité et histoire dans ledit hebdomadaire, la réflexion est menée sur les liens entre le roman historique, la presse et l’émergence du concept de nation chinoise.
Renewable Hydrogen-Based Energy System for Supplying Power to Telecoms Base Station
Authors: Luta Doudou Nanitamo , Raji Atanda K.
Published: June 2019

Hydrogen is likely to play a significant role in the concept of low-carbon power generation in support to renewable energy systems. It is abundant, eco-friendly, highly efficient and have the potential to be more cost-effective than fossil fuels provided that the engineering challenges associated with its safe infrastructure development, economical extraction and storage are solved. Presently, about 50 million metric tons of hydrogen is generated on a yearly basis, most of that is used for oil refining and ammoniac production. Other applications include electric vehicles, power to gas and power generation, etc. This study focuses on the use of hydrogen for power generation. The main goal is to investigate technical and economic performances of a renewable hydrogen-based energy system as an alternative to diesel generators for powering a remote telecoms base station. The proposed energy system consists of a photovoltaic generator, an electrolyser, a fuel cell, a hydrogen tank, a battery storage system and a power-conditioning unit. The system is simulated using Homer Pro software.
Fatigue Resistance of BBSG Asphalt Mix with Recycled Asphalt Aggregate Addition
Authors: Bordjiba Abdelhak , Rhailia Hassib
Published: June 2019

Climatic and traffic effects are the causes of aging of the surface layer of asphalt, which leads to the necessary renovation of the latter. The use of waste from the tread layer provides a viable and beneficial solution for the environment and the economy. However, this solution must meet the requirement of sustainable development, which necessitates that a road has a very long lifespan. In this study we investigated the performance of recycled asphalt in terms of fatigue (as an element of life-cycle control). All the formulas were tested by the fatigue test in order to define the influence of the proportions of the asphalt aggregates, penetrability of the new binder used, and the manufacturing temperature. The results obtained showed the relationship between the contribution binder (reproduced between the new binder and the old binder) and the fatigue resistance under the influence of the parameters that we have mentioned above. At the end an optimization study has been carried out in order to determine exactly the doses required to formulate recycled asphalt resisted to fatigue The optimization seeks to maximize the asphalt aggregates and minimize the temperature of manufacture with a class of the binder compatible.
Analysis of Resonance Oscillations of Extruder Elastic Screw Conveyor
Authors: Lyashuk Oleg , Sokil Maria , Vovk Yuriy , Levkovych Mykhaylo , Tson Oleg , Kondratyuk Dmytro , Dmytrenko Viktor
Published: June 2019

The relationship of oscillations amplitude of the granular medium-elastic screw system whilst passing over resonance at different values of the bulk mass per unit length at different motion velocity has been studied. The relation of resonance oscillations of the granular medium-elastic screw system described by ratio α(t) and ν(t) has been shown. Based on these ratios, we plotted time variations of amplitude against quick passing over resonance.
Intelligent Symbiotic Relay Selection Technique for 5G Networks
Authors: Ndubuaku Maryleen U. , Okafor Kennedy Chinedu , Udeze Chidiebele Chinwendu , Salih Omar
Published: June 2019

The growing demand for bandwidth and spectrum has inspired the ongoing efforts to establish the future 5G network supporting vertical sectors such as cyber-physical systems (CPS). Cooperative communication is one of the requisite techniques to improve coverage, network capacity and reduce power consumption in the network. In this paper, a symbiotic two-phase intelligent transmission is considered. The first phase occurs between the source and the candidate relays, and involves the selection of a set of “reliable relays”. The second phase occurs between the reliable relays and the destination, and involves the selection of the “best relay” for transmission. Dynamic relay selection using k-means clustering is used to detect the most significant correlation between all the channel state information (CSI) attributes in the system. The work identified the reliable relays while reducing the number of relay nodes for the second transmission phase. Contextual scenarios are created with typical network configuration using three geographical locations Coventry, Birmingham and London. An experimental validation is done with Omnet++ environment for the scenarios of three geographical locations. A natural grouping of mobile users is carried out leveraging the relay capabilities. The results are validated using support vector machine (SVM) classification algorithm. Considering urban environment deployment of relay nodes, metrics such as signal-to-noise-plus-interference ratio (SINR), attenuation, signal to noise ratio (SNR), link quality, k-means clustering, accuracy, and root mean square error (RMSE) are investigated for the Direct-2-Direct (D2D) capable relays. It was observed that the proposed technique both outperforms the other fixed-parameter relay selection techniques and improves with larger datasets unlike the other techniques.
Preparation of Gold Nanowires by Photochemical Glucose Reduction
Authors: Li Zi Jing , Jiang Yan , Feng Shao Ping , Sun Li Da , Zhou Bo
Published: June 2019

HAuCl4 was reduced by glucose as reducing agent and dispersant under UV radiation and acetone as photo sensitizer. The experimental samples were characterized by the transmission electron microscopy and UV-visible spectrophotometer, and the results show that these gold nanoparticles’ size is uniform, monodisperse distribution of spherical particles of average diameter of 5.8 nm, and gold nanowires with two-dimensional network structure were successfully prepared. The influence of glucose concentration on reaction under this condition and the mechanism of nucleation and growth of the photochemical reduction were discussed.
Firs-Principles Investigation of the Electronic and Optical Properties of B-Doped ZnO under Pressure
Authors: Xiao Ling Ping , Liu Yun Qin
Published: June 2019

Based on the density functional theory (DFT), the first-principles approach is used to study the electronic band structure of B-doped wuritzite ZnO with different pressure. The pressure effects on the lattice parameters, electronic band structures, and partial density of states (PDOS) of crystalline B-doped ZnO are calculated up to 8 GPa. Moreover, the evolution of the dielectric function, absorption coefficient (), reflectivity (), and the real part of the refractive index () at high pressure are also presented. Keywords: high pressure; density functional theory; B-doped ZnO.
Analysis of Plastic Properties of Fe-Based Coatings at Different Annealing Temperatures by Nanoindentation
Authors: Yu Zhe , Yang Hao Yue , Song Zi Kun , Lin Sui Xuan , Li Hua Yi
Published: June 2019

Fe-based alloys were deposited on 1045 steel by plasma cladding technique and the specimens were annealed at different temperatures. Instrumented indentation technique was adopted to investigate the plastic properties of the coatings, especially the stress-strain relations, critical yield stress and the strain hardening exponent. The results show that the elastic recovery in nanoindentation is less than 20% for all coatings and proves an obvious existence of plastic deformation in the coatings. It is found in the stress-strain curves that the annealing process makes the distribution of elastic modulus among the whole coating more uniformly. With the penetration depth increasing, the initial plastic deformation value gradually decreased which is more obvious for coatings annealing at high temperatures. In addition, the strain hardening exponent of the as-cladding coating and coatings annealed at 500°C keeps steady around 0.15 while the corresponding values of coatings annealed at 600°C and 700°C increased sharply with the penetration depth increasing and the maximum value is up to 0.32.
First-Principles Study on Crystal Configuration and Many-Body Cohesive Energy of Solid Argon
Authors: Fu Xi Jin
Published: June 2019

Based on the first-principles, using CCSD(T) ab initio calculation method, many-body potential energy of solid argon are accurately calculated with the atomic distance R from 2.0Å to 3.6Å at T=300K, and firstly establish and discuss the face-centered cubic (fcc) atomic crystal configurations of two-, three-, and four-body terms by geometry optimization. The results shows that the total number of (Ar)2 clusters is 903, which belongs to 12 different geometric configurations, the total number of (Ar)3 clusters is 861, which belongs to 25 different geometric configurations, and the total number of (Ar)4 clusters of is 816 which belongs to 27 different geometric configurations. We find that the CCSD(T) with the aug-cc-pVQZ basis set is most accurate and practical by comprehensive consideration. The total potential energy Un reachs saturation at R>2.0Å when the only two-and three-body interaction energy are considered. When R≤2.0Å, the total potential energy Un must consider four-and higher-body interaction energy to achieve saturation. Many-body expansion potential of fcc solid argon is an exchange convergent series.
The Study on Sintering Capabilities of High Purity Metal Vanadium Powder
Authors: Wang Yan Hui , Liu Qi , Bo Xin Wei , Wang Xiao Yu , Jiang Chun Dong , Tang Rui
Published: June 2019

High purity metal vanadium powder was milled by high energy ball milling, and the grain size and morphology of vanadium powder was observed by electron probe, and the stress-strain curve was measured by CMT5305 universal testing machine for research of the mechanical property. In order to investigate the effect of sintering process on the property of product, the vanadium powder was sintered by the hot pressing sintering process and the cold isostatic pressing with vacuum sintering process respectively. The experimental results show that for the cold isostatic pressing with vacuum sintering process, the density of raw compact increases with the increase of pressing pressure. When the pressure increases to 280 MPa, the density and relative density of raw compact are 3.99 g·cm-3 and 66.94% respectively, the density and relative density of product after sintering are 5.28 g·cm-3 and 88.59% respectively. With the pressure increasing from 80 MPa to 200 MPa, the compressive strength increases significantly from 0.4 MPa to 6.0 MPa, the pressure increases to 280 MPa, the compressive strength slowly increases to 7.4 MPa. For the hot pressing sintering process, the relative density of product is higher than that of cold isostatic pressing with vacuum sintering process, and the density and relative density reach to 5.51 g·cm-3 and 92.91% respectively under 280 MPa pressure.
Effect of Magnesium to Phosphorus Ratio on Properties of Magnesium Phosphate Cement
Authors: Wen Jin Bao , Tang Xiu Sheng , Xu Zhi Feng , Zhu Ye Ran
Published: June 2019

The effects of the ratio of magnesium to phosphorus (Mg/P) on the compressive strength, bond strength, drying shrinkage and pH value of magnesium phosphate cement (MPC) were investigated. The results show that the consistent effect of the ratio of Mg/P on compressive strength and bond strength, as the ratio increases, the strengths are both first increased and then decreased, and the best ratio is 3:1. For setting time and drying shrinkage, the effects of the ratio of Mg/P are both obvious. Mainly manifested as the increase of the ratio, all of them show a decreasing trend. And the setting time can be shortened by 78%, furthermore, 28d the maximum drying shrinkage rate can be reduced by 29%. The effect of the ratio of Mg/P on pH value is mainly that when the ratio increases, the time of the inflection point of pH value is obviously advanced, and their final pH value is close.
Dynamic Mitochondrial Migratory Features Associated with Calcium Responses during T Cell Antigen Recognition
Authors: He Luye , Raddatz Andrew D. , Zhou Fangyuan , Hwang Hyundoo , Kemp Melissa L. , Lu Hang
Published: June 2019

A T cell clone is able to distinguish Ags in the form of peptide–MHC complexes with high specificity and sensitivity; however, how subtle differences in peptide–MHC structures translate to distinct T cell effector functions remains unknown. We hypothesized that mitochondrial positioning and associated calcium responses play an important role in T cell Ag recognition. We engineered a microfluidic system to precisely manipulate and synchronize a large number of cell–cell pairing events, which provided simultaneous real-time signaling imaging and organelle tracking with temporal precision. In addition, we developed image-derived metrics to quantify calcium response and mitochondria movement. Using myelin proteolipid altered peptide ligands and a hybridoma T cell line derived from a mouse model of experimental autoimmune encephalomyelitis, we observed that Ag potency modulates calcium response at the single-cell level. We further developed a partial least squares regression model, which highlighted mitochondrial positioning as a strong predictor of calcium response. The model revealed T cell mitochondria sharply alter direction within minutes following exposure to agonist peptide Ag, changing from accumulation at the immunological synapse to retrograde movement toward the distal end of the T cell body. By quantifying mitochondria movement as a highly dynamic process with rapidly changing phases, our result reconciles conflicting prior reports of mitochondria positioning during T cell Ag recognition. We envision applying this pipeline of methodology to study cell interactions between other immune cell types to reveal important signaling phenomenon that is inaccessible because of data-limited experimental design.
Cars and Clouds: New Drivers for Efficient Power Management
Authors: Seddon Mike
Published: June 2019

The electrification of transportation and the continued expansion of cloud based computing are two drivers for optimizing power efficiency. The automotive power requirements focus on highly efficient transfer from DC to AC (and vice versa), at very high power levels. Current IGBT switching devices are packaged in large modules with extensive cooling capacities. Reductions in size/weight require increased efficiency at higher frequency and current density. The desire for higher efficiency in datacenters is aimed at cost reduction of the total compute environment. Each individual server requires the most efficient power conversion from high voltage distribution lines to very low voltage boards. Switching devices again are packaged in modules, operating at very high power density, requiring co-optimization of devices, connections and packages. To realize the desired combination of size, speed and density, wide bandgap materials may be needed to advance the roadmap of these power management products. We will review some of the recent progress and challenges in materials innovation to optimize device and package and circuit.
IC MARKET UPDATE AND CHINA IMPACT ANALYSIS
Authors: McClean Bill
Published: June 2019

A high level of uncertainty looms over the global economy and sales of smartphones are beginning to saturate. However, the Internet of Things, driver assisted autos, and AI hold promise for the future. In order to make sense out of the current turmoil, a top-down analysis of the IC market will be given and include trends in worldwide GDP growth, electronic system sales, and semiconductor industry capital spending. A critical look at China's ambitions to become a bigger player in the IC industry will also be presented.
Sensor Integration: Feynman or Moore?
Authors: Vigna Benedetto
Published: June 2019

Sensors are all around us: they are in cars, in smartphones, in factories, in pacemakers, in drones, in smart speakers and in many other places with the ultimate goal to sense and to monitor parameters of importance and interest in our daily environment. They play an essential bridge between electronic systems and the user or environment.

Today they already enable a multibillion dollar industry and they continue to create new business opportunities in many markets, such as automotive, consumer and personal electronics. Most importantly they are the enablers of emerging applications in Healthcare Industry and Industrial Internet of Things. There is no doubt that sensors will leave a sign in the new generation of home and factory robots, the autonomous cars, enabled by Artificial Intelligence. Thanks to their high reliability, high performances and low manufacturing cost, the most commercially successfull sensors available today are realized in silicon (i.e. Image Sensors and MEMS) and they use the same manufacturing techniques of the CMOS industry, whose evolution has been dictated by the famous G. Moore's law. Since the market for silicon sensors has been much smaller than overall semiconductor industry, sensors have been always classified as part of the so called “More than Moore” world. There are many books, article and publications on “More than Moore” subject, but considering the strong contribution to the sector given by the visionary Nobel Prize P. R. Feynman, envisioning the possibility to miniaturize the microsystems and to stack specialized silicon wafers to realize a complex versatile microsystem, time is come to see the Sensors as part of the “Feynman Roadmap” instead of “More than Moore” roadmap. After an extensive look-back over the current situation, this talk will address the future challenges of “Feynman Roadmap.”
Package Technologies for the 4th Industrial Revolution
Authors: Oh Dan
Published: June 2019

The 4th Industrial Revolution with artificial intelligence, autonomous vehicles, robotics, and biotechnology demands power efficient computing devices such as GPU, TPU, and FPGA. To further enhance the performance, advanced System-in-Package (SiP) such as 2.5D and 3D integration technologies are needed to satisfy the high computing and power efficiency requirements.

High-performance SiP systems must integrate advanced packaging technologies with both complex signal/power integrity and enhanced thermal solutions. In addition, package developers need to work closely with chip designers at a very early stage of the product development to achieve the target performance and reliability.

In this Keynote, Dr. Oh, Vice President of Package Development at Samsung Electronics will start with an overview of the evolution and importance of package technology to meet the needs of emerging high-end computing platforms. Furthermore, a high-performance SiP system with a Fan Out (FO) package is introduced for power efficient mobile platforms. In addition, the extension of the FO package for high-end server applications is discussed. Finally, pros and cons of the FO package compared to 2.5D Si-interposer are discussed.
Versatility of Fan Out – Simple 2D to Complex 3D
Authors: Hunt John
Published: June 2019

Many mobile applications strive for the thinnest package possible, and therefore benefit from the high density of basic Fan Out technology. At the same time, Fan Out has evolved from a simple, single die packaging solution into a high-density solution enabling more complex 2D and 3D connectivity.

Fan Out first went into volume manufacturing in 2009 with a simple, single die package using eWLB. For the next few years, it was only thought of in this context. Then in 2016, two packages came into production that broke this stereotype. The first was a hybrid, very high-density Fan Out combined with a BGA package called FOCoS for server applications. The second was a 3D PoP structure for mobile cellular phone applications called InFO. With these structures, Fan Out became a more versatile tool, capable of wider applicability. And since then, multiple manufacturers have continued the evolution of Fan Out's capabilities into more and more packaging opportunities.

This presentation will illustrate how the integration of a wide variety of packaging technologies, wafer level processing, substrate evolution and Flip Chip packaging have all come together into both simple and complex packages structures. We will further explore the higher levels of integration and sophistication available using Fan Out as a basic manufacturing technology, describing the evolving functionality and complexity achieved by combining low cost materials and innovative process flows. By using such combinations of tools and processes, the resulting packages are only limited by our imagination and creativity.
Temporary and permanent bonding enables 3D integration of ultrathin wafers
Authors: Brandl Elisabeth , Uhrmann Thomas , Pires Mariana , Jung Stefan , Burggraf Jürgen , Koch Matthew
Published: June 2019

Rising demand in memory is just one example how 3D integration is still gaining momentum. Not only the form factor but also performance is improved for several 3D integration applications by reducing the wafer thickness. Two competing process flows using thin wafers are to carry out for 3D integration today. Firstly, two wafers can be bonded face-to-face with subsequent thinning without the need to handle a thin wafer. However, some chip designs require a face-to-back stacking of thin wafers, where temporary bonding becomes an inevitable process step. In this case, the challenge of the temporary bonding process is different to traditional stacking on chip level, where usually the wafers are diced after debonding and then stacked on chip level, which means die thicknesses are typically in the range of 50 μm. The goal of wafer level transfer is a massive reduction of the wafer thickness. Therefore temporary and permanent bonding has to be combined to enable stacking on wafer level with very thin wafers. The first step is temporary bonding of the device wafer with the temporary carrier through an adhesive interlayer, followed by thinning and other backside processes. Afterwards the thinned wafer is permanently bonded to the target wafer before debonding from the carrier wafer. This can be repeated several times to be suitable for example a high bandwidth memory, where several layers of DRAM are stacked on top of each other. Another application is the memory integration on processors, or die segmentation processes.

The temporary bonding process flow has to be very well controlled in terms of total thickness variations (TTV) of the intermediate adhesive between device and carrier wafer. The requirements for the temporary bonding adhesive include offering sufficient adhesion between device and carrier wafer for the subsequent processes. The choice of the material class for this study is the Brewer Science dual layer material comprising of a curable layer which offers high mechanical stability to enable low TTV during the thinning process and a release layer for mechanical debond process. The release layer must lead to a successful debond but prevent spontaneous debonding during grinding and other processes. Total thickness variation values of the adhesive will be analyzed in dependence of the adhesive layer thickness as this is a key criterion for a successful implementation at the manufactures. Besides the TTV the mechanical stability during grinding will be evaluated by CSAM to make sure no delamination has happened.

For feasibility of the total process flow it is important that the mechanical debonding requires less force compared to the separation of the permanent bonded wafers. Other process parameters such as edge trimming of the device wafer as well as edge removal of the mechanical debond release layer are investigated.
Dicing Tape Performance in a Plasma Dicing Environment
Authors: Fulton Stewart , Ansell Oliver , Hopkins Janet , Umemoto Taku , Nishida Takuo
Published: June 2019

Plasma dicing, as a means of isolating individual integrated circuits from within a fully processed semiconductor substrate, is still an emerging technology but is now considered the latest step in the evolution in device singulation. With the trend towards smaller, thinner more robust devices, many chip manufacturers are considering, or already switching, to a plasma dicing approach.[1, 2] The high aspect ratio, deep reactive ion etching of silicon using a Bosch process, leverages some distinct advantages over the more physical methods of device singulation. [3] Although the more established methods of diamond blade saw dicing, various laser based approaches or laser/mechanical hybrid dicing techniques, all introduce an element of heat and in some cases water for cooling purposes, they do not expose dicing tape to the unique conditions within high vacuum plasma. This work investigates how the properties of both dicing tape and adhesive are affected when exposed to the environment of a plasma dicing process used in the semiconductor industry. A preliminary fitness test utilising an aggressive exothermic etching regime was used to establish the compatibility of a range of standard Lintec Adwill dicing tapes. In essence, a measure of base film thermal conductivity and how quickly some of the lower molecular weight volatile components of base film and adhesive materials are boiled off or ‘out-gassed’. Polyvinyl Chloride (PVC) tapes performed less well than Polyethylene terephthalate (PET) tapes and some of the Polyolefin (PO) tapes exhibited the greatest resilience. A design of experiments to measure changes in tensile strength, elongation and adhesive properties were carried out to assess the performance of plasma dicing on PO low adhesion tape. Figure 2 shows that the samples exposed to an SF6 plasma impacted the tape elongation and tensile strength properties. Typically the stretch required for PnP is in the range 1–10 % showing that the plasma dicing does not impact the overall performance of the tape. Further tests employing a die pick-up force measurement system to compare saw diced die with that of plasma diced die, proved the feasibility of this technology. Figure 3 shows that pick-up force measured on plasma diced dies is comparable with saw diced dies.
Development of High Density RDL Technologies for Panel Level Processing
Authors: Böttcher Lars , Karaszkiewicz S. , Schein F. , Kahle R. , Ostmann A.
Published: June 2019

Advanced packaging technologies like wafer-level fan-out and 3D System-in-Packages (SIPs) are rapidly penetrating the market of electronic components. A recent trend to reduce cost is the extension of processes to large manufacturing formats, called Panel Level Packaging (PLP). In a consortium of German partners from industry and research advanced technologies for PLP are developed. The project aims for an integrated process flow for SIPs with chips embedded into an organic laminate matrix.

At first dies with Cu pillar structures are placed into openings of a laminate frame layer with very low coefficient of thermal expansion (CTE). They are embedded by vacuum lamination of thin organic films, filling the very small gap down to 15 μm between chips and frame. The frame provides alignment marks for a local registration of following processes. The ridged frame limits die shift during embedding and gives a remarkable handling robustness. Developments are initially performed on a 305×256mm2 panel format, aiming for a final size of 610×615 mm2. On the top side of embedded chips, a 20μm dielectric film is applied. The goal is to avoid additional via formation and to realize a direct connection between the Cu pillar of the die and the RDL

The RDL formation is based on semi-additive processing. Therefore a Ti or TiW barrier and Cu seed layer is sputtered. Subsequently a 7μm photoresist is applied and exposed by a newly developed Direct Imaging (DI) system. Lines and spaces of 4μm were achieved with high yield. In the following, Cu is simultaneously electroplated for the via contacts and interconnects traces.

Finally, the photo resist is stripped and the TiW barrier and Cu seed layers are etched.

The goal of the development is to provide a technology for a high-density RDL formation on large panel sizes.

The paper will discuss the new developments in detail, e.g. the influence of most significant process parameters, like lithographical resolution, minimum via diameter and the placement and alignment accuracy on overall process yield.
Embedded SIP Modules for next-GEN Heterogeneous “POWER-Devices”
Authors: Moody Kevin , Stukan Nick
Published: June 2019

In this paper will focus on the comprehension of System-in-Package (SiP) with embedded active and passive components integration will be described. Embedding of semiconductor chips into substrates provides many advantages that have been noted. It allows the smallest package form-factor with high degree of miniaturization through sequentially stacking of multiple layers containing embedded devices that are optimized for electrical performance with short and geometrically well controlled copper interconnects. In addition, the embedding gives a homogeneous mechanical environment of the chips, resulting in good reliability at system level. Furthermore, embedded technology is an excellent resolution to Power management challenges dealing with new device technologies (Si, GaS, GaN) and optimization on the thermal dissipation with improved efficiency. Embedded technology comes with many challenges in 2019, primarily design for manufacturability (DFM) and maturity. Customers are looking for better-performance capability and pricing normally that means same or lower than die free package cost (DFPC) comparison. This paper will discuss the challenges bring to market the Embedded SIP Modules for next-GEN Heterogeneous “POWER-Devices” Today, the embedded process is being developed by printed circuit board (PCB) manufacturers creating a new supply chain, bringing new players into the semiconductor industry. This new supply chain comes along with new business models. As a result of the increasing interest in implementing embedding technologies, ACCESS Semiconductors in China is committed to be a leader in the adaptation of embedding technologies, with over 10-yrs mature coreless technology and proved design rules for low profile dimensions with seamless Ti/Cu sputtering and Cu pillar interconnect giving advantages in both electrical & power performance. ACCESS Patented “Via-in-Frame” technology provides High Reliability (MSL1, PCT, BHAST) at Cost Effective in high panel utilization for HVM, using standard substrate/PCB known material sets, no need for wafer bumping/RDL, over-mold or under-fill cost adders. ACCESS Semiconductors is currently in HVM on single die 2L, and LVM on multi-devices actives/passives 4L SiP construction both platforms are driven from the power market segment. In-development on Die Last & Frameless (MeSiP) platforms utilizing hybrid technology (mSAP) and Photo Imageable Dielectric (PID) materials for cost down solutions in HVM by Q1FY2020. Also, ACCESS Semiconductors total turn-key solutions will include front-of-line (FOL) and end-of-line (EOL) capability from wafer handling, back-grinding, and dicing with KGD traceability thru the embedded chip process, frame/strip singulation, FT, marking pack & ship providing additional 30% cost reduction in the future. Here's an illustration of Embedded Technology Roadmap and Product Platforms.
Ultra-low Warpage and Anhydride-free Liquid Compression Molding Materials for Advanced Semiconductor Packaging
Authors: Champagne Tim , Chao Jay , Tanaka Kazuyasu , Trichur Ramachandran , Zhang Rong
Published: June 2019

Advanced semiconductor packaging landscape is rapidly evolving to accommodate requirements of front end node shrink and performance expectations from emerging applications in big data, artificial intelligence, mobile and autonomous driving. Multiple innovations in packaging process technology as well as processing materials enable the progress in advanced packaging. Several wafer level packaging (WLP) platforms have emerged recently using fan-in, fan-out, 2.5D and 3D packaging processes to satisfy the requirements of increased functionality, reduced form factor, lower power consumption, and high reliability. These often-conflicting requirements drive the design and development of many new electronic materials including liquid compression molding (LCM) for Fan-In and Fan-Out WLPs. Historically, anhydride-based LCM materials have been used to balance the material properties to achieve consistent dispensability, high quality molding, and high mechanical stability during grinding, RDL, and singulation processing. However, stricter environmental regulations driven by EU REACH stipulates complete replacement of anhydride resins with more environmentally friendly raw materials while still providing the same or better performance.

Most recently, Henkel has developed new platforms of anhydride-free LCM materials with reduced cure shrinkage, ultra-low warpage, good chemical resistance, and high reliability. LCM material choice is integral to the package design and end use as this material needs to withstand several thermal, mechanical, chemical and vacuum processes during the construction of the package and stringent reliability conditions. By judicious construction of the polymer network, appropriate filler selection, and controlled cure kinetics design, the cure shrinkage and warpage were significantly reduced over other designs.

Furthermore, the low warpage stability of the molded wafer is maintained through post-mold curing, PI simulation, and RDL simulation process steps ultimately leading to improved reliability performance. Compared to traditional anhydride-based LCM, our reliability data (after 96 hours of uHAST & 1000 cycles of AATC) clearly indicates performance advantages of no filler-fall-off, no delamination, and better chemical resistance. In terms of workability, the new system shows improved work-life, fast-cure at 110–130°C, and complete gap filling. Lower die shift, good mold release, and improved tape debonding has also been observed through formulation and process optimization. Taking advantage of the proprietary resin and formulation design, Henkel's new LCM materials are delivering positive results in new FO-WLP designs and WLCSP applications needing 5-side or 6-side protection.
Rapid On-Substrate Curing of Thick Protective Package Sealing for Automotive Assembly
Authors: Moore John , Spencer Jevon
Published: June 2019

Protective encapsulant and sealing materials that cure upon delivery are desired for high volume automotive assembly. Unlike many coatings created for electronics, these materials are milimeters thick and have desirable elastomeric properties to withstand decades of stress. While the Automotive Electronics Council (AEC) stress test qualification for integrated circuits (AEC Q100, 1994) may set material temperature resistance at 150C, targets of 200C or 250C are desirable. The ideal polymer exhibits low permeability, effectively creating a barrier to moisture, chemicals, and gases that may emanate anywhere on the chassis. While conventional Buna and Viton rubbers represent a major share of gasketing to protect electronic packages, their design and manufacturing infrastructure cannot meet the pace of prototyping. Polymer compositing with reactive diluents now makes it possible to use CAD fed delivery tools that cure on-contact. Such robotic operated equipment delivers by variable syringe head design on vertical, overhead, or irregular surface contours. Sealant forms that once took months with costly quantity orders, now take seconds in the lab and on the assembly floor. Daetec has created a technology that meets these rapid assembly requirements with properties that exceed the current AEC targets. A complete process will be presented with state of the art LED fiber optic curing on the substrate. Data and application results using comparative specimens will be presented.