Level Packaging Research Articles

A Fuzzy Approach for Estimating Quality of Aspect Oriented Systems

Modern civilization cannot survive without software. Because software is the building block of new generation, the quality of software plays an important role in building new technologies and hence, low quality software is not acceptable. Any software is defined by its internal and external characteristics. To measure software quality, its internal attributes such as cohesion, coupling, etc. are used to assess the external quality attributes such as Reusability, Maintainability etc. Very few researchers has worked on assessing external attributes by measuring internal attributes for object oriented systems and all work has been done at class level by using class level metrics. Since classes are not suitable for large applications with higher level of organisation, packages were introduced. Organizing classes into package enhances the Reusability and Maintainability task for object oriented systems. Aspect oriented systems are designed to enhance object oriented systems by modularizing crosscutting concerns like logging, synchronization etc., which are scattered in multiple classes. In this paper, efforts have been made to assess external attributes—Reusability, Maintainability and Understandability, using internal attributes for Aspect oriented systems at package level using fuzzy logic. Software reusability and maintainability improves the quality of software product by reducing development/maintenance time, effort and cost. On the other hand, software Understandability directly or indirectly affects the quality of software. In this paper, fuzzy approach is proposed for assessing the three external attributes using package level internal attributes. Predictions made from the proposed fuzzy approach are validated by analyzing them with the values of external attributes measured for AJhotdraw, an AspectJ software. The results have shown that the predictions made through the proposed approach are correct.

Notice of Retraction: Extension of the Unmatched-Media Time Reversal Method to Locate Longitudinal Soft Defects in Transmission Lines

This paper applies the electromagnetic time reversal method to the identification of the location and to the quantification of the impedance Zd of longitudinal defects along transmission lines. A closed-form expression for the time-reversal current transfer function is derived. This new transfer function benefits from the same properties of that for solid or soft transversal faults, and hence, can be used for locating the defects along the line. Different scenarios are considered ranging from power lines to signals channels for high-speed digital systems at printed circuit board and package level. The results are discussed and used to assess the accuracy and scalability of the proposed method.

Characterizing the nuclease accessibility of DNA in human cells to map higher order structures of chromatin.

Packaging of DNA into chromatin regulates DNA accessibility and consequently all DNA-dependent processes. The nucleosome is the basic packaging unit of DNA forming arrays that are suggested, by biochemical studies, to fold hierarchically into ordered higher-order structures of chromatin. This organization has been recently questioned using microscopy techniques, proposing an irregular structure. To address the principles of chromatin organization, we applied an in situ differential MNase-seq strategy and analyzed in silico the results of complete and partial digestions of human chromatin. We investigated whether different levels of chromatin packaging exist in the cell. We assessed the accessibility of chromatin within distinct domains of kb to Mb genomic regions, performed statistical analyses and computer modelling. We found no difference in MNase accessibility, suggesting no difference in fiber folding between domains of euchromatin and heterochromatin or between other sequence and epigenomic features of chromatin. Thus, our data suggests the absence of differentially organized domains of higher-order structures of chromatin. Moreover, we identified only local structural changes, with individual hyper-accessible nucleosomes surrounding regulatory elements, such as enhancers and transcription start sites. The regulatory sites per se are occupied with structurally altered nucleosomes, exhibiting increased MNase sensitivity. Our findings provide biochemical evidence that supports an irregular model of large-scale chromatin organization.

Silicon Photonic Switch Fabrics: Technology and Architecture

Photonic switching technologies show potential for transforming communication networks across diverse markets from long-haul to short-reach distance scales due to their large bandwidth density, high energy efficiency, and potential for low cost. In recent years, numerous outstanding advancements have been made in scaled silicon photonic switching fabrics: spanning a variety of manufacturing platforms and packaging methods, relying on different switching mechanisms, and assembled on-chip in a diverse mixture of loosely related architectures. This paper reviews the current approaches employed by leading researchers in this area, and surveys the state of the art in achieved performance at both the technological and the architectural level. Specifically, we consider thermo-optic, electro-optic, and MEMS-based switch actuation embedded in Mach–Zehnder interferometer, ring resonator, and directional coupler based silicon photonic switches. We define common metrics and compare performances. We outline critical requirements for constructing scaled switch fabrics from elementary cells. We investigate similarities and differences between a number of commonly utilized topologies. And, we survey recent accomplishments in scaled switch fabrics at the chip and package level. Moving these demonstrations from research to product will require many further advancements, and we highlight areas that we believe will be critical for market adoption.

Chip Package Interaction: Understanding of Contributing Factors in Back End of Line (BEoL) Silicon, Cu Pillar Design and Applied Process Improvements

Abstract This paper describes major contributing factors to the CPI risk and reveals the mitigation strategy successfully applied jointly by GLOBALFOUNDRIES as the silicon supplier and Qualcomm Technologies, Inc., as the customer responsible for packaging. This strategy involves thermo-mechanical modelling, data collection on wafer level using shear test to assess the BEoL-stability, Cu Pillar process development and optimization. The qualification of these process changes had been completed and implemented in volume production. The paper also discusses mechanical wafer level and thermo-mechanical package modeling approaches. A model has been applied to determine the critical factors on BEoL stress/strain during the flip-chip assembly reflow process. These factors include for instance the Cu Pillar bump geometry and stack up. The results of the modelling work were used to set up experiments to further mitigate CPI related failure modes in BEoL on the package level. GLOBALFOUNDRIES and Qualcomm Technologies, Inc., assessed Cu Pillar design related rules such as Cu Pillar diameter and height as well as the Cu Pillar stack up. Process improvements were carried out to reduce the undercut of the barrier underneath the Cu Pillar. The paper reveals how effectively an optimized Cu Pillar design and improved Cu Pillar processing can contribute to the risk mitigation of CPI failure modes in the BEoL for critical package designs and assembly processes with low margin against BEoL fracture during solder reflow. Furthermore, process improvements applied to enhance the BEoL stack strength were investigated and have been implemented in high-volume production. A strong correlation was established between data collected on wafer level to assess the BEoL strength and data collected on package level.

Universal Connection Matrix: A Breadboard in a Package

Abstract Process improvements driven by Moore's Law have created disparate processes for different best-in-class components, such as analog sensors, digital processors, RF electronics, and power electronics. Therefore, it becomes impossible to integrate all components of a system into a single System-on-Chip (SoC) giving rise to System-in-Package (SiP) devices which integrate multiple components together at the package level. However, traditional SiP devices are monolithic systems that have a fixed design and require a large investment to update or modify. To avoid the fixed nature of SiP devices and improve the ability to prototype with SiP technology, this paper presents the Universal Connection Matrix (UCM), a breadboard in a package.

Advanced Packaging for Automotive Dashboard Application

Abstract The current automotive market for the integrated circuit (IC) packaging industry has grown significantly due to the increasing need for automation and higher performance in vehicles. These changes in the automotive market will enable cars to be more reliable and intelligent. To address the increasingly complex demands of the automotive market, the semiconductor packaging industry is shifting its focus to prioritize the development of advanced packages for next generation automotive market requirements. Automotive IC's are traditionally wirebond packages. Due to the increasing complexity and higher performance requirements of automotive applications, the packaging industry is moving towards high performance flip chip packages for automotive infotainment, GPS, and radar applications. In this study, a comprehensive view of the evolving packaging landscape from traditional wirebond to flip chip interconnect to advanced fan-out wafer level packages will be discussed. The pros and cons of each packaging technology will be examined. Packaging roadmap details will be discussed along with assembly process information, determining the right bill of materials (BOM), and extensive package and board level reliability (BLR) including grade 1 and grade 0 reliability data will be discussed.

Systematic Design of Ka-band Transmitter Modules using the M3-Approach

Abstract In this work, we present and illustrate a holistic approach, the M3-approach (methodologies, models, measures), for efficient and accurate design of Ka-band transmitter modules in earth stations on mobile platforms (ESOMPs) for satellite communication applications. We begin by applying this approach to derive the system specifications, considering the application and international regulatory requirements. Based on these specifications, we derive the system/transmitter architecture, and then specify the components of this architecture. Furthermore, we develop a concept for low-cost realization of the transmitter module, and a concept for testing the module. For the implementation of the realization concept, 3D full-wave electromagnetic-based models are developed at the packaging and component levels. To verify these models, test samples are fabricated and measured. Excellent correlation is obtained between measurement and simulation results. The verified models are applied to optimize the RF performance of the Ka-band transmitter components and modules.

COST AND QUALITY FOCUSED SUITABLE BOX DETERMINATION WITH DESIGN OF EXPERIMENT: A CASE OF A GLASSWARE COMPANY

There is an increasing competition between companies for their survival in today’s business environment. Not only time but also cost parameters affect the company’s sustainability performance. Logistics as one of the core operations of companies has a large share on expenses. Transport, warehousing, administration, packaging, and other indirect costs constitute the main cost values of logistics. Especially product damages caused by incorrect packing and transportation leads to extra expenditures to the companies and damages their reputation due to the customer dissatisfaction. In order to avoid such situations, proper level of packaging for protection, transportation conditions, features of the product like fragility, compactness, must be selected and matched correctly. On the other hand, some external factors such as temperature and humidity, which affect the quality of cardboard, also need to be considered in the production phase. In this study, a Design of Experiment methodology is performed to determine the suitable conditions for increasing the strength of the corrugated cardboard box that is used by a Glassware Company operating in Turkey. 3 k full factorial design approach is implemented for the analysis and box compression test is used for measurement. The discussed factors and the interactions of the factors were evaluated with the help of Minitab software.

Ultra-Fine Pitch Wedge bonding for Device Reliability Characterization

Abstract Intel's EM (electromigration) package level stress lab has historically used 1mil aluminum wire to bond to pads 53 μm by 60 μm, with a pitch of 86 μm by 88 μm. The lab was challenged to align its wedge bonding capabilities to match the pitch used at wafer level probing with a pad size of 30 μm by 37 μm and pitch of 43 μm by 50.6 μm. In order to achieve the 43 μm by 50.6 μm pitch, 0.7 mil aluminum wire and an ultra-fine pitch wedge was used. In this paper, the benefits or matching the wafer level probe card capabilities are discussed as well as the concerns and considerations of implementing such a small pitch process. The primary concerns are heel shorting and bond placement repeatability but many factors influence these parameters. A brief summary of electrical testing performed to validate the process is discussed as well as new challenges that have arose due to the new testing capabilities.

Electrothermal coupling analysis and experimental verification for wirebond devices

The thermal performance of a powered wirebond device with package level and board level test specimens was investigated by both analytical and experiment methods. The effects of thickness and thermal conductivity of the molding compound and heat spreader attached to the top surface of the molding compound on the performance of the Au wire and silicon die were modeled and evaluated by three-dimensional electrothermal coupling analysis. An advanced quad flat no-lead (QFN) sample was selected to experimentally measure the maximum allowable current in Au wire for packages either with or without molding compound. Two failure modes, namely the fusing of the wire and the decomposition temperature of the molding compound, were established in analysis. A board level test specimen with a thermal test die was also employed to measure the real time package thermal performance. The major achievement of this work is in the complete combination of modeling, experiment, and optimization for thermal performance evaluation purpose of a powered wirebond device. Results of this physical analysis can provide a reliable and useful guide to estimate the maximum allowable currents in Au wires for a wirebond device under practical application conditions.

Effect of Edible Coatings Based on Oxidized Cassava Starch and Vacuum Packaging on Physicochemical Properties of Minimally Processed Yam

This research studied the effect of edible coatings based on oxidized cassava starch and two conditions of packaging (vacuum and non-vacuum) on physicochemical properties of minimally processed yam. A factorial arrangement of 24 was applied to the following factors: oxidized starch of yucca (3 and 5%), ascorbic acid (0.5 and 1%), carnauba wax (0.1 and 0.2%), determining the physicochemical properties of minimally processed yam for 42 days. High concentrations of acid and wax decreased the pH and the acidity of yam by 10.2 and 5.25%, respectively. A vacuum packaging and high levels of wax increased the acidity by 10.8% and a non-vacuum packaging with the same level of wax deceased it by 5.76%. The moisture content increased by 3.24% and the total solids decreased by 2.48% in a vacuum packaging in low concentrations of wax, due to the weak barrier caused by wax at low concentrations. Weight loss increased with the time of storage, as a cut produces cells breakage which in turn, results in a greater moisture loss. Finally, 0.5% of acid and 0.1% of wax in the coating maintain the physicochemical properties of yam.

A survey of mobile cloud computing offloading concepts based on measurements and algorithms

Handheld computing devices at the moment everywhere in the arms of generation dependent human beings of every age. Clients are looking for new innovative thoughts to first and best utilization of Smart Mobile Devices. The rapid enlargement of the number of clever telephone users has given rise of various research subjects. While the technological advancements are happening from hardware and package levels, novel ideas are being introduced. One amongst those ideas is Mobile Cloud computing which is the mix of cloud computing, mobile compu-ting and wireless networks to bring wealthy process resources to mobile users, network operators, yet as cloud computing suppliers. MCC offloading is a technique to overcome the barriers like battery life, memory usage, computation difficulties faced in Mobile computing with the help of cloud. This survey not only focuses on the concepts of offloading, it also concentrates on the measurements and basic ideas of Mobile Cloud computing related algorithms.

KARAKTERISTIK BUTIR SOAL TRY OUT UJIAN NASIONAL SMA MATA PELAJARAN MATEMATIKA Se-KOTA MATARAM DENGAN MENGGUNAKAN PROGRAM ITEMAN

The purpose of this research was to know how characteristic items of Try Out National Exam Year 2010/2011 at Senior High School on Mathematics Subject in Mataram City that analyzed by using Iteman Program. The characteristic in question was whether the item can be used or not based on the difficulty level of the item, the difference in power, and the functioning of the answer option. The research method used was descriptive. Techniques of collecting data in the form of documents. Source of data in the form of answer sheet of computer package 61 of Try Out National Exam Year 2010/2011 at Senior High School on Mathematics Subject in Mataram City. Aspects analyzed by using this Iteman Program include the level of difficulty item, different power, and the function of whether or not the answer choice. Based on the results of Item of Analysis Try Out National Examination of School Year 2010/2011 Senior High School on Mathematics Subjects in Mataram City by using Iteman Program, it can be concluded that for the level of difficulty Package 61 was classified. Different power for package 61 has a good category. For the reliability of having a high category and a matter of Try Out Package 61 there are 23 problems received with the improvement of 4, 5, 8, 9, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 26, 28, 30, 31, 32, 34, 35, 36, and 40. Improvements need to be made on the less functioning effluent. There are 15 accepted questions: 1, 2, 3, 7, 10, 11, 12, 13, 15, 27, 29, 33, 37, 38, and 39. And there are 2 rejected questions 6 and 25.

HIV-1 adaptation studies reveal a novel Env-mediated homeostasis mechanism for evading lethal hypermutation by APOBEC3G.

HIV-1 replication normally requires Vif-mediated neutralization of APOBEC3 antiviral enzymes. Viruses lacking Vif succumb to deamination-dependent and -independent restriction processes. Here, HIV-1 adaptation studies were leveraged to ask whether viruses with an irreparable vif deletion could develop resistance to restrictive levels of APOBEC3G. Several resistant viruses were recovered with multiple amino acid substitutions in Env, and these changes alone are sufficient to protect Vif-null viruses from APOBEC3G-dependent restriction in T cell lines. Env adaptations cause decreased fusogenicity, which results in higher levels of Gag-Pol packaging. Increased concentrations of packaged Pol in turn enable faster virus DNA replication and protection from APOBEC3G-mediated hypermutation of viral replication intermediates. Taken together, these studies reveal that a moderate decrease in one essential viral activity, namely Env-mediated fusogenicity, enables the virus to change other activities, here, Gag-Pol packaging during particle production, and thereby escape restriction by the antiviral factor APOBEC3G. We propose a new paradigm in which alterations in viral homeostasis, through compensatory small changes, constitute a general mechanism used by HIV-1 and other viral pathogens to escape innate antiviral responses and other inhibitions including antiviral drugs.

Multi-Azimuth Failure Mechanisms in Phosphor-Coated White LEDs by Current Aging Stresses

We have experimentally analyzed multi-azimuth degradation mechanisms that govern failures of commercially-available high-power (1 Watt) phosphor-coated white (hppc-W) light-emitting diodes (LEDs) covered with peanut-shaped lenses under three current-stress aging (CSA) conditions. Comprehensive analyses focus on photometric, chromatic, electrical, thermal and packaging characteristics. At the packaging level, (a) the decrease of the phosphor-conversion efficiency; (b) the yellow-browning of the optical lens; and (c) the darkening of the silver-coated reflective layer deposited with extraneous chemical elements (e.g., C, O, Si, Mg, and Cu, respectively) contribute collectively to the integral degradation of the optical power. By contrast, Ohmic contacts, thermal properties, and angles of maximum intensity remain unchanged after 3840 h aging in three cases. Particularly at the chip level, the formation of point defects increases the number of non-radiative recombination centers, and thus decreases the optical power during aging stages. Nevertheless, in view of the change of the ideality factor, the Mg dopant activation and the annealing effect facilitate the increase of the optical power in two specific aging stages (192 h~384 h and 768 h~1536 h). This work offers a systematic guidance for the development of reliable LED-based light sources in general-lighting areas.

Thermal Interface Materials and Cooling Technologies in Microelectronic Packaging—A Critical Review

The ever increasing demand for fast computing has led to heterogeneous integration of packages as can be seen in the latest Xeon family segments in the market. Microprocessors are now adjacent to memory chips, transceivers, field-programmable gate arrays, and even other microprocessors within a single substrate. These complex designs have instigated an increase in cooling demand for microprocessors, and hence, there has been an increased focus within the semiconductor industry on developing advance thermal solutions. From the packaging level, thermal interface materials (TIMs) play a key role in thermally connecting various components within the package and helps reduce the thermal resistance between the die surfaces and integrated heat spreaders. From the system level, cooling technology is critical to attain the desired overall thermal dissipation and performance. In this review, progress made in the area of TIMs and system cooling solutions are presented. The focus is on the evolution of TIMs and cooling technologies and their challenges in the integrated circuit packaging. Merits and demerits of various TIM materials available in the commercial market are also discussed. The article will be concluded with some directions for the future that would be potentially very beneficial.

Effect of nanocomposite-based packaging and chitosan coating on the physical, chemical, and mechanical traits of strawberry during storage

The combined use of fruit coating with nanocomposite packaging film is a novel technique for maintaining the quality and assisting more appropriate storage conditions. In the present study, a novel nanocomposite-based packaging was prepared by blending polypropylene and polyolefin elastomer with nanoclay. Strawberry fruit (Gavita cultivar) was evaluated for determining the effect of chitosan coating, packaging with polyethylene film and clay nanocomposite film on physical, chemical, and mechanical traits. Dependent variables including chemical (pH and Brix percentage), physical (color and weight loss), mechanical properties (firmness and elasticity modulus) and independent variables including two temperature levels (including 25 and 4 °C), two packaging levels (with polyethylene and with clay nanocomposite films), and two chitosan coating levels (including chitosan coating and without coating) were selected and analyzed based on the completely randomized multivariate factorial design. The results showed that main and interaction effects of studied factors were significant on color parameters, weight loss, pH, Brix percentage, firmness, and elasticity modulus. Finally, the outputs indicated that the coated samples packed with the clay nanocomposite film had the most optimal mode in terms of the changes in physical, chemical, and mechanical properties during the storage period. The variations of the dependent parameters at 4 °C were less than that at 25 °C during the storage period. The results showed that shear force and stress in nanocomposite film are higher than polyethylene film. Therefore, the coated samples packed with the clay nanocomposite film could be used to improve the shelf life of strawberry fruit.

Control of insulin granule formation and function by the ABC transporters ABCG1 and ABCA1 and by oxysterol binding protein OSBP.

In pancreatic β-cells, insulin granule membranes are enriched in cholesterol and are both recycled and newly generated. Cholesterol’s role in supporting granule membrane formation and function is poorly understood. ATP binding cassette transporters ABCG1 and ABCA1 regulate intracellular cholesterol and are important for insulin secretion. RNAi inter­ference–induced depletion in cultured pancreatic β-cells shows that ABCG1 is needed to stabilize newly made insulin granules against lysosomal degradation; ABCA1 is also involved but to a lesser extent. Both transporters are also required for optimum glucose-stimulated insulin secretion, likely via complementary roles. Exogenous cholesterol addition rescues knockdown-induced granule loss (ABCG1) and reduced secretion (both transporters). Another cholesterol transport protein, oxysterol binding protein (OSBP), appears to act proximally as a source of endogenous cholesterol for granule formation. Its knockdown caused similar defective stability of young granules and glucose-stimulated insulin secretion, neither of which were rescued with exogenous cholesterol. Dual knockdowns of OSBP and ABC transporters support their serial function in supplying and concentrating cholesterol for granule formation. OSBP knockdown also decreased proinsulin synthesis consistent with a proximal endoplasmic reticulum defect. Thus, membrane cholesterol distribution contributes to insulin homeostasis at production, packaging, and export levels through the actions of OSBP and ABCs G1 and A1.

EPP Particles Surface Modification Technique and the Performance of the Experiment Research

In order to improve the bond performance of EPP particles and concrete matrix materials in EPP load-bearing insulation concrete, the mechanical properties of EPP load-bearing insulation concrete are improved. Introduces the EPP (polypropylene) particles surface modification processing methods and preparation technology of the EPP bearing insulation concrete, by controlling the single variable test method, determine the amount of modifier and modified EPP particle surface gelled material suitable package level, and analyzes the modifier on the properties of EPP bearing insulation concrete mechanism.