bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine Pitch Paste for System-in-Package Applications
Authors: Ruifen Zhang , Murali Sarangapani , Sureshkumar Vinobaji , Lingling Teo , Keong Loke Chee , Li-San Chan 
Published: December 2018

Abstract
Water soluble solder paste developed using T7 powder particles revealed good solderability when printed on copper, tin, gold flash nickel plated surfaces and on reflow as well. Its cross-section showed absence of voids, good wetting and soldering to the plated surfaces with angle of contact from 42° to 84° on reflow. All the solder interface are integral with pad/substrate surfaces and revealed formation of tin based intermetallics. T7 solder powder processed using Welco technology showed spherical, clean, smooth, un-agglomerated powder particles with the size range of 2 to 12μm. The developed solder paste is used for fine pitch applications.
Elevated Stand-Off Heights in Solder Joint Interconnections of Surface Mounted IC Packages Result in Appreciable Stress and Warpage Relief
Authors: Suhir Ephraim , Yi Sung , Hwang Jennie S. , Ghaffarian R. 
Published: December 2018

Abstract
The “head-in-pillow” (HnP) defects in lead-free solder joint interconnections of IC packages with conventional (small) stand-off heights of the solder joints, and particularly in packages with fine pitches, are attributed by many electronic material scientists to the three major causes: 1) attributes of the manufacturing process, 2) solder material properties and 3)design-related issues. The latter are thought to be caused primarily by elevated stresses in the solder material, as well as by the excessive warpage of the PCB-package assembly and particularly to the differences in the thermally induced curvatures of the PCB and the package. In this analysis the stress-and-warpage issue is addressed using an analytical predictive stress model. This model is a modification and an extension of the model developed back in 1980-s by the first author. It is assumed that it is the difference in the post-fabrication deflections of the PCB-package assembly that is the root cause of the solder materials failures and particularly and perhaps the HnP defects. The calculated data based on the developed analytical thermal stress model suggest that the replacement of the conventional ball-grid-array (BGA) designs with designs characterized by elevated stand-off heights of the solder joints could result in significant stress and warpage relief and, hopefully, in a lower propensity of the IC package to HnP defects as well. The general concepts are illustrated by a numerical example, in which the responses to the change in temperature of a conventional design referred to as ball-grid-array (BGA) and a design with solder joints with elevated stand-off heights referred to as column-grid-array (CGA) are compared. The computed data indicated that the effective stress in the solder material is relieved by about 40% and the difference between the maximum deflections of the PCB and the package is reduced by about 60%, when the BGA design is replaced by a CGA system. Although no proof that the use of solder joints with elevated stand-off heights will lessen the package propensity to the HnP defects is provided, the authors think that there is a reason to believe that the application of solder joints with elevated stand-off heights could result in a substantial improvement in the general IC package performance, including, perhaps, its propensity to HnP defects.
Ultra-Fine Pitch Wedge bonding for Device Reliability Characterization
Authors: Badger Lacey L. , Toledo Nikholas G. , Slottke Derek W. , Thomas John , Alamillo Miguel , Gunnarsson Elliott , Le Rutt Mark L. , Tsameret Ilan 
Published: December 2018

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.
Process Development of Al-alloy Wire Bonding for High-Temperature Power Electronics
Authors: Che Xuan , Xu Tao , Fu Jason , Niayesh Omid 
Published: December 2018

Abstract
In this work, process parameters are developed for an Al-alloy wire for high-temperature power electronics. Shear and pull forces of the bonds on IGBT devices reach 2200 g and 1100 g respectively, without causing any die cratering. Comparison of the Al-alloy wire and standard Al wire bonded on battery cells shows that both the pull and shear forces of the bonds with the Al-alloy wire are improved by ~20%. This indicates that this Al-alloy wire potentially could be used for bonding on the power electronics and batteries in automotive industry, where better mechanical strength and wider bond window are required.
Intelligent Production of Wire Bonds using Multi-Objective Optimization – Insights, Opportunities and Challenges
Authors: Unger Andreas , Hunstig Matthias , Meyer Tobias , Brökelmann Michael , Sextro Walter 
Published: December 2018

Abstract
Ultrasonic wire bonding is an indispensable process in the industrial manufacturing of semiconductor devices. Copper wire is increasingly replacing the well-established aluminium wire because of its superior electrical, thermal and mechanical properties. Copper wire processes differ significantly from aluminium processes and are more sensitive to disturbances, which reduces the range of parameter values suitable for a stable process. Disturbances can be compensated by an adaption of process parameters, but finding suitable parameters manually is difficult and time-consuming. This paper presents a physical model of the ultrasonic wire bonding process including the friction contact between tool and wire. This model yields novel insights into the process. A prototype of a multi-objective optimizing bonding machine (MOBM) is presented. It uses multi-objective optimization, based on the complete process model, to automatically select the best operating point as a compromise of concurrent objectives.
Comparisons of Soldering Alloys in Large Ceramic Substrate to Metal Heatsink Attachment Application
Authors: Wang Frank Fan , McKeague William , Polwarth Christina 
Published: December 2018

Abstract
Tin-lead alloys have historically been popular in the electronics industry for use in solder-attach applications. Despite recent restrictions related to lead content, some industries continue to use lead based alloys in solder applications. Tin-lead based alloys, in particular, have proven to have excellent solderability to tin, nickel, copper, gold, and silver metallization surfaces. They have also performed better in reliability than most of the lead free solders. As a result of this, they are still widely used in the aerospace and military electronics industry.
Hybrid microelectronics built for space applications use both Tin-Lead-Silver Alloy Sn62 and Lead Free Soldering Alloy Sn96; these solders are used both for wire and component attach as well as substrate to header attach.
This article discusses the differences of these two solders, using both literature and experimental study. Experimental testing involving pull tests further supports this conclusion.
Mechanical Insertion and Reliability Testing of Thermal Interface Materials for Semiconductor Test and Burn-in Applications
Authors: Saums Dave , Jensen Tim , Gowans Carol , Homer Seth , Hunadi Ron 
Published: December 2018

Abstract
Semiconductor test and burn-in requirements for thermal interface materials (TIMs) are challenging, with difficult mechanical reliability requirements that are not found in other types of applications for these materials. To demonstrate the ability of certain newly-developed TIMs to not only provide suitable thermal performance for the device under test and meet these mechanical requirements, a contact cycling test has been devised in three phases for evaluating TIM mechanical performance and durability.
Novel formaldehyde-free electroless copper for plating on next-generation substrates
Authors: Wendeln Christian , Steinhäuser Edith , Stamp Lutz , Dosse-Gomez Bexy , Langhammer Elisa , Reiber Sebastian , Dünnebeil Sebastian , Röseler Sandra 
Published: December 2018

AbstractThis work describes a new type of formaldehyde-free electroless copper electrolyte that can be used for a broad set of applications and materials, especially for the processing of next-generation substrates. The plating solution was successfully applied in both, a laboratory and production-scale environment. The results have been evaluated in detail and were benchmarked against a formaldehyde-based reference. A characterization of the obtained metal films was carried out by different analytical techniques, including microscopy, X-ray fluorescence (XRF), scanning electron microscopy (SEM), adhesion tests and non-blister verification. Additionally, studies concerning chemical bath stability, throwing power and electrical reliability have been made. Based on the obtained data we believe that the current achievements represent a suitable technology to replace formaldehyde in existing printed circuit board (PCB) production without loss of process performance and thus provide a sustainable “green” alternative to the industry.
Optimization of Cupric Chloride Subtractive Etching for Cu High Density Interconnects
Authors: Lambert Alexander , Issac Goutham , Salunke Ashish , Lu Luwen , Chyan Oliver 
Published: December 2018

Abstract
The continuously increasing demand for innovation in the miniaturization of microelectronics has driven the need for ever more precise fabrication strategies for device packaging, especially for printed circuit boards (PCBs). Subtractive copper etching is a fundamental step in this processes, requiring very precise control of etch rate and etch profile. Cu etching baths are typically monitored with several parameters including oxidation-reduction potential, conductivity, and specific gravity. However, the etch rate and etch profile can be difficult to control even under strict engineering controls of those monitoring parameters. The mechanism of acidic cupric chloride etching, regeneration and recovery is complex, and the current monitoring strategies can have difficulty controlling the complex interlocking chemical equilibria. We report that thin-film UV-Vis spectroscopy has the capability to effectively monitor the complex changes to the etch bath. UV-Vis also reveals various underlying mechanism reasons for etch bath behavior and illuminates the roles of H+ and Cl− to the etch bath while also providing a means to monitor the Cl−. Furthermore, UV-Vis can be utilized to improve current monitoring strategies, as it can identify and predict etching behavior that the current standard methodologies may have difficulty predicting.
Development of skills and tools for micro opto-electrical integration on wafer level
Authors: Schröder Saskia , Stenchly Vanessa , Quenzer Hans-Joachim , Reinert Wolfgang 
Published: December 2018

Abstract
New devices for a digital lifestyle like augmented reality (AR) glasses may find their wide spread use only if consumer relevant pricing can be achieved. Low cost RGB-light sources are a key element for AR. assembly productivity for these micro opto-electrical RGB-light sources and a further reduction in their package dimensions. We present our new approach to build miniature RGB-light sources on structured silicon wafers and elaborate the required skill set and our future process infrastructure based on our existing high volume capable optical packaging platform. The platform provides an optical bench with integrated heat spreader and emission windows enabling miniature hermetic housing for laser diodes assemblies on 8″ wafers.
Laser Power Supply Thermo-Structural Analysis for the Mars 2020 Rover
Authors: Cepeda-Rizo Juan , Tuman David 
Published: December 2018

Abstract
Operation of the Laser Power Supply (LPS) module provides the dual challenge of high power dissipation, and the need for strict dielectric isolation, while needing to survive in an environment on Mars that will see a chilly night-time temperature of −123°C, and to a daytime instrument environment in excess of 50°C. Additionally, power restrictions prevent the use of survival heating during the night. The harsh mechanical vibration environment of launch and landing provides an additional challenge to reliability. A multi-physics simulation was created that took into account temperature property variations, as well as solving the transient analysis that also included rapid variation in power-pulsing during the operation of the laser. The steady state analysis employed a more traditional finite element based analysis, but with provisions for Mars gas convection and thermal radiation.
MOCVD Copper Metallization for High Aspect Ratios TSV 3D Integration.
Authors: Fadloun Sabrina , Stephens Dean , Gergaud Patrice , Blanquet Elisabeth , Mourier Thierry , Jones Chris , Burgess Steve , Rastogi Amit 
Published: December 2018

Abstract
MOCVD (Metal-Organic Chemical Vapor Deposition) copper metallization was developed on 300mm wafers, to fulfil 3D Through-Silicon Via (TSV) interconnect requirements. Using a fluorine-free organometallic precursor, the bis(dimethylamino-2-propoxy)copper (II) Cu[OCHMeCH2NMe2]2 at low temperature deposition, we developed a high purity, low stress copper film with strong adhesion to a TiN barrier layer. Argon was used as a carrier gas and H2 and/or H2O as a co-reactant. This MOCVD technique offers good conformality observed with 10μm×120μmTSVs. The thin copper seed layer was successfully integrated on 300mm wafers. A new XRD protocol was developed to characterize the copper seed layer along the TSV sidewalls, revealed higher microstructure quality, lower stressed in the case of copper film deposited by CVD compared to those deposited by i-PVD.
Productivity Comparison of Wafer Transport Architectures in PVD Tools Used for Fan-Out Packaging RDL Barrier/Seed Formation
Authors: Bluck Terry , Smith Chris , Werbaneth Paul 
Published: December 2018

Abstract
Physical Vapor Deposition (PVD) systems are widely used in the semiconductor fabrication industry, both for front-end applications in the wafer fab and for back-end applications at device packaging houses. In fan-out wafer level packaging (FOWLP), and in fan-out panel level packaging (FOPLP), sputter deposited Ti and Cu are the base on which electroplated copper Redistribution Layers (RDLs) are built. For these RDL barrier/seed layers, PVD cluster tools, wafer transport architectures that have been widely used since the mid-1980s, are the current Process of Record (POR) in advanced packaging; however, these tools typically operate in a regime where wafer transport is robot-limited to approximately 50 wafers per hour, which limits overall throughput and greatly influences Cost of Ownership (COO) for the sputter deposition step(s), because the central handling robot occupied with a transfer from the Ti PVD module to the Cu PVD module, for example, has no opportunity to be doing anything other than that specific transfer.
Other wafer transport architectures are more efficient from a wafer handling perspective. In linear transport carrier-based PVD tools, wafers or panels passing through the system benefit from a mechanical transfer time budget that is considerably less than for a cluster tool. Transport time overhead per wafer on linear transport systems is quite low, and scheduler software optimization becomes less onerous too, as a result of the simpler wafer transport architecture.
We analyzed the relative throughput of cluster and linear transport PVD tools for a typical FOWLP barrier/seed layer (1000Å Ti / 2000Å Cu) sputter deposition process, and present details here of how the time spent moving wafers to various processing chambers affects overall system productivity. In the case of the cluster tool architecture, with its central wafer handling robot, wafer throughputs are approximately 50 wafers per hour, while on the linear transport system wafer throughputs as high as 240 wafers per hour are possible. The significant difference in system throughputs greatly affects the relative Cost of Ownership (COO) per wafer processed, with the linear transport system returning COO results that are less than half those of the typical cluster PVD tool.
Ultra-Wideband High Gain Vivaldi Antennas Using Additive Manufacturing
Authors: Ghazali Mohd Ifwat Mohd , Chahal Premjeet 
Published: December 2018

Abstract
In this paper, a low-cost fabrication technique using additive manufacturing (3D printing) is demonstrated for the fabrication of ultra-wide band (UWB) Vivaldi antennas. In communications, UWB antennas are required that have high gain and wide bandwidth (3.1 GHz to 10.6 GHz) enabling high-data rates and efficient use of frequency spectrum. 3D printing has evolved into an important technology that allows rapid and simple fabrication method for printing antennas, and other components. Two different Vivaldi antennas designs (i) Vivaldi with a slot line, and (ii) Corrugated Vivaldi are presented. The fabricated antennas have a wide bandwidth of 14 GHz and a high gain of 10 dBi. For example, the corrugated antenna exploits the capability of 3D printing to incorporate slots in the design that aids in low frequency matching with increased gain.
Aqueous Washable Thermal Resistant Coatings and Adhesives
Authors: Moore John 
Published: December 2018

Abstract
Many packaging processes require thin and fragile components to be protected or held securely in place for temporary periods of time. The most common process flow is to: apply the coating, cure or use to bond a device, conduct the process, and finish with removing the coating by washing in a liquid chemistry. Aqueous cleaning is deemed safer for devices on organic laminates and in the presence of molding compounds. These reagents use water as their major constituent. They are compatible with organic substrates (panels, laminates, boards), are worker safe, and require less expensive operating equipment. Aqueous washing is generally green and exempt from the complexity and cost of environmental and waste management regulations. Daetec's washable coatings qualify as green, and exhibit thermal resistance over 300°C, making them one of the most unique materials on the market. These coatings enable soldering, laser processing, plasma etching, and dielectric curing, all following with simple water washing. Water washable DaeCoatTM 525 is a key choice in laser processing for debris removal around the heat activation zone (HAZ), while the etch-resistant DaeCoatTM 534 supports laser patterning for plasma singulation [1]. While DaeCoatTM 532 is water soluble, another material from the same family, DaeCoatTM 537 is not, yet will wash away in an aqueous surfactant, DaeClean™ S20 (10% in water). In many ways, these products act, as surfactants, but depending upon the chemistry, will dissolve in water or an aqueous agent. Customers desiring a green protective coating or adhesive for plating or etching processes, may apply DaeCoatTM 537, send through the processes, and then wash away in the S20 aqueous agent. All products are cast from water. Film forms as 50μm thick with peel away liners are available for DaeCoatTM 532 and 537. UV curable high solids versions are also available. Applications include planarizing coatings, adhesive for die solder attach, and C4 or micro bump protection. Protective coatings for EMI/RFI shielding, dicing operations, and temporary bonding operations that may use porous carriers have been demonstrated with water washable coatings and adhesives. The success in these and related temporary applications depend upon the use of the proper washable coating. Our experience in creating solutions for these and other industry needs will be discussed as well as the criteria for using temporary washable coatings.
Molecular epidemiology of non-viral sexually transmitted infections in the central Alpine province of Bolzano, northern Italy from April 2016 to March 2017
Authors: Aschbacher Richard , Romagnoli Francesca , Masi Elisa , Pasquetto Valentina , Perino Franco , Eisendle Klaus , Braghetto Monica , Messini Sergio , Delbue Serena , Pagani Elisabetta 
Published: December 2018

Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Ureaplasma parvum, Ureaplasma urealyticum, Mycoplasma hominis and Mycoplasma genitalium are established or presumed as (??) STI pathogens. The present study aims at ng describing the one-year molecular epidemiology of these seven pathogens in the Province of Bolzano, Northern Italy. From April 2016 to March 2017, a total of 2,949 patients, mainly females, were enrolled and 3,427 urine, vaginal, endocervical and/or urethral samples were subjected to simultaneous analysis of the seven pathogens by means of Real Time Polymerase Chain Reaction (AnyplexTM II STI-7 Detection Kit Seegene, Seoul, Korea). At least one of the seven microorganisms was detected in 40.7% of patients, with an uneven distribution: 43.1% in females (F) and 29.8% (p<0.001) in males (M). The prevalence of microorganisms was as follows: 30.3% U. parvum (F: 35.6%, M: 8.3%), 6.9% U. urealyticum (F: 6.8%, M: 7.0%), 4.9% M. hominis (F: 5.4%, M: 2.3%), 4.9% C. trachomatis (F: 3.4%, M: 11.4%), 1.1% M. genitalium (F: 1.0%, M: 1.2%), 1.2% N. gonorrhoeae (F: 0.17%, M: 5.6%) and 0.40% T. vaginalis (F: 0.38%, M: 0.53%). Mixed infections were detected in 7.4% of patients. The highest prevalence was observed for U. parvum, followed by U. urealyticum and M. hominis and a significant presence of multi-pathogen infections was registered.
Historical Determinism in the Constitution of the United States and the Spanish Constitution of 1812
Authors: Gurpegui José Antonio 
Published: December 2018

The Constitution of the United States has not been a document specially referred to, nor considered, by Spanish academics who have studied the Constitution of 1812. Even the constitutionalists gathered in Cádiz fled from anything that could evoke a republican and federalist constitution being their purpose radically different. In a general way, it has been the French Constitution of 1791, the reference text “par excellece”. But, beyond the liberal principles that Americans and most of the Spaniards embraced, there were some historical coincidences in the United States and Spain which conditioned in a similar way the final result of both political documents.