bluuebunny/crossref_metadata_2025_split huggingface dataset:
Search for Continuous Gravitational Waves from Scorpius X-1 in LIGO O2 Data
Authors: Zhang Yuanhao , Papa Maria Alessandra , Krishnan Badri , Watts Anna L. 
Published: January 2021

Abstract
We present the results of a search in LIGO O2 public data for continuous gravitational waves from the neutron star in the low-mass X-ray binary Scorpius X-1. We search for signals with ≈ constant frequency in the range 40–180 Hz. Thanks to the efficiency of our search pipeline we can use a long coherence time and achieve unprecedented sensitivity, significantly improving on existing results. This is the first search that has been able to probe gravitational wave amplitudes that could balance the accretion torque at the neutron star radius. Our search excludes emission at this level between 67.5 and 131.5 Hz, for an inclination angle 44° ± 6° derived from radio observations, and assuming that the spin axis is perpendicular to the orbital plane. If the torque arm is ≈26 km—a conservative estimate of the Alfvén radius—our results are more constraining than the indirect limit across the band. This allows us to exclude certain mass–radius combinations and to place upper limits on the strength of the star’s magnetic field with a different probe than ever used before. We also correct a mistake that appears in the literature in the equation that gives the gravitational wave amplitude at the torque balance and we re-interpret the associated latest LIGO/Virgo results in light of this.
Distribution of wild bee (Hymenoptera: Anthophila) and hoverfly (Diptera: Syrphidae) communities within farms undergoing ecological transition
Authors: Noel Grégoire , Bonnet Julie , Everaerts Sylvain , Danel Anouk , Calderan Alix , de Liedekerke Alexis , de Montpellier d'Annevoie Clotilde , Francis Frédéric , Serteyn Laurent 
Published: January 2021

In Havelange (Belgium), two farms are experiencing an ecological transition. We aimed to evaluate the impact of their agricultural activities on insect pollinator communities. This article depicts the situation at the very early stage of the farm transition. This study supports the fact that the maintenance of farm-level natural habitats provides environmental benefits, such as the conservation of two important pollinator communities: wild bees and hoverflies.Over two years (2018-2019), by using nets and coloured pan-traps, we collected 6301 bee and hoverfly specimens amongst contrasting habitats within two farmsteads undergoing ecological transition in Havelange (Belgium). We reported 101 bee species and morphospecies from 15 genera within six families and 31 hoverfly species and morphospecies from 18 genera. This list reinforces the national pollinator database by providing new distribution data for extinction-threatened species, such asAndrena schenckiMorawitz 1866,Bombus campestris(Panzer 1801),Eucera longicornis(L.) andHalictus maculatusSmith 1848 or for data deficient species, such asA. semilaevisPérez 1903,A. fulvata(Müller 1766),A. trimmerana(Kirby 1802) andHylaeus brevicornisNylander 1852.
Thermal improvement in 3D embedded modules using copper bar vias
Authors: Kakade Manoj , Dowling Richard , Bora Mumtaz , Tubbs Jake , Maghawri Ahmed 
Published: January 2021

Abstract
The combination of increased I/O density, reduced footprint, and multi-die capability within a single platform makes embedded die an attractive solution. The benefits of embedding active die include miniaturization, improved electrical & thermal performance, heterogeneous integration, and an opportunity for cost reduction.
Currently vertical integration is happening in power management chips with embedded components integrated into modules. Heat dissipation in integrated 3D high efficiency power modules is challenging when die is embedded inside the substrate. Heat dissipation affects efficiency and electro-migration of the packaged structures.
Copper bar vias can be replaced for circular vias in the substrate design for thermal improvement. The thermal improvement is simulated using Ansys FEM (Finite Element Method) tools.
Construction Kit of RF-Blocks in Package Technologies
Authors: Hopsch Fabian , Trieb Robert , Heinig Andy 
Published: January 2021

Abstract
Advanced packages are necessary to cope with the requirements of 5G and radar technologies with 60 GHz and beyond. For proper RF design with rising package technology requirements demands for usage of predefined structures with predefined layout elements, manufactured and measured elements. This paper deals with an approach to have such elements available to build advanced types of packages in shorter time compared to classical approaches. The approach is a general approach but it is demonstrated with an advanced two-level package-on-package technology with a leading edge IC technology. It is also used explain the build-up of a construction kit of RF-blocks from the design phase of test structures up to measurement of such structures, qualification and model building. From the test structure more general structures can be derived and used in the design of future 5G applications. This enables better time-to-market, reduces cost and provides higher design validation in terms of first time right.
Electromigration in Power Devices
Authors: Zhuang Hao , Bauer Robert , Dinkel Markus 
Published: January 2021

Abstract
In the power semiconductor industry, there is continuous development towards higher maximum current capability of devices while device dimensions shrink. This leads to an increase in current density which the devices have to handle, and raises the question if electromigration (EM) is a critical issue here. Generally, an EM failure can be described by the Black’s equation with temperature and current density as the main influencing factors. Normally, the current that the power packages need to handle lies in the range of 100 A. However, it should be noted that power devices exhibit asymmetric sizes of drain and source contacts. This may lead to higher current density at the source leads (area ratio drain/source: ~8x for QFN 5×6). Nevertheless, the source lead area is still much larger than that of the flip chip bumps (i.e., 28 times larger compared to a 100 μm micro-bump). This typically enhances the safety of the power device with respect to EM. However, with regard to future development towards higher maximum current capability, we intended to investigate further on the EM of power devices.
In the present work, we focused on the PQFN 5×6 package to study the EM behavior of a power device soldered on a Printed Circuit Board (PCB). We employed the highest current (120 A) and temperature (150 °C) that the stress test system could handle to study EM in accelerated mode. First fails occurred after ~1200 h, which was much earlier than expected from previous flip-chip investigations. In addition, we found separation gaps in the solder joint between drain contact and PCB, which experienced the lowest current density in the whole test. Contradictorily, we observed only minor solder degradation at the source interface, regardless of the higher current density there. Nevertheless, the separating metal interfaces still correlated well with the current direction. Thermal simulations revealed that due to the self-heating of the device by the high current applied, both the drain and source leads were exposed to much higher temperatures (Tmax = 168 °C) than the PCB board which was kept under temperature control at 150 °C. This temperature difference resulted in a thermal gradient between the device and PCB which, in turn, triggered thermal migration (TM) in addition to EM. As TM for the drain contact occurred in the same direction as EM, it enhanced the degradation effect and therefore led to a shorter time-to-failure at the drain. In contrast to this, such an enhanced effect did not occur at the source side. As a result, we observed higher solder degradation at the drain side, which we did confirm by switching the current direction in the test.
To minimize the TM effect, a special EM test vehicle, which used a Cu plate instead of the MOSFET chip, was designed and fabricated. Thermal simulation verified that the device operated at similar temperatures as the PCB board. Using this setup, it was possible to study EM in an accelerated mode and, thus, investigate the pure EM behavior of the power device.
Ultra-low Residue Flux Applications in RF Front-End Packages
Authors: Hu Leo , Lim Sze Pei 
Published: January 2021

Abstract
With the leap into the 5G era, the demand for improvements in the performance of mobile phones is on the rise. This is also true for the quantity of radio frequency (RF) front-end integrated circuits (ICs), especially for RF switches and low noise amplifiers (LNA). It is well-known that improvements in performance depend on the combination of new design, package technology, and choice of materials. Ultra-low residue (ULR) flux is an innovative, truly no-clean, flip-chip bonding material. By using ULR flux, the typical water-wash cleaning process can be removed and, in some instances, package reliability can be improved as well. This simplified assembly process will help to reduce total packaging costs. This paper will discuss the application of ULR fluxes on land grid arrays (LGAs) and quad-flat no-leads/dual-flat no-leads (QFN/DFN) packages for RF front-end ICs, as well as the reflow process. The solder joint strength and reliability study will be shared as well.
A novel approach to mitigate stress induced defects at metal-dielectric interface in Redistribution layers for 3D IC stacking
Authors: Kumar Amit , Chacon Jose , Gelzinis Peter , Morris Julio , Velaga Ankineedu 
Published: January 2021

Abstract
The reliability of a redistribution layers in 3D IC is dependent on how well the different shape and size of metal connection with varying density are connected at the different metallization levels. The widely different coefficient of thermal expansion of metal (Cu ~16.5 × 10−6 m/mK) and dielectric (SiO2 ~ 3 × 10−6 m/mK) often leads to defects, such as cracking at the metal-dielectric interface. In this work, we present a manufacturing level friendly process modification to the conventional approach to present an almost crack free metal-dielectric interface for subsequent processing in the RDL fabrication. After the copper electroplating and chemical mechanical planarization (CMP), we use a cap layer to protect the top layer and anneal the metal. Finally, we repeat the CMP to remove the cap layer before sending the wafers for subsequent processing.
Evaluating thermoset resin substrates for 3D mechatronic integrated devices and packaging
Authors: Häußler Felix , Shen Shengxia , Petillon Simon , Weser Sascha , Haybat Mehmet , Eberhardt Wolfgang , Zimmermann André , Franke Jörg 
Published: January 2021

AbstractMiniaturization efforts and increasing demands regarding reliability of mechatronic systems require new materials and processes for the 3D mechatronic integrated devices (3D-MID) technology. Currently, in the area of 3D-MID mostly thermoplastic materials are in use in the industry, which are metallized using the LPKF-LDS® process. This paper is supposed to demonstrate the eligibility of thermoset resins as a new material class for 3D-MID applications and as a packaging option for silicon chips which are currently encapsulated using transfer molding of thermosets. The reliability of the conductor tracks made using a LDS-additive free process as well as the adhesion forces are investigated. Different laser parameters for structuring of two different substrate materials are compared. For reliability testing a thermal shock test is applied. Furthermore, the adhesion is tested using Hot-Pin-Pull testing. The conductor tracks surpass 2000 cycles thermo-mechanical load without showing strong deterioration of the track resistivity. The incorporated approach enables electrically reliable functionalization of packaged dummy chips including vias for connection to terminals on the chips. The results of the tested injection moldable thermoset resins are comparable to state-of-the-art 3D-MID thermoplastic substrates and thus, suited as circuit carrier material in electronic packaging.
Optimization of High-Speed Electrolytic Plating of Copper Pillar to Achieve a Flat Top Morphology and Height Uniformity
Authors: Ikumoto Raihei , Itakura Yuki , Tachibana Shinji , Yamamoto Hisamitsu 
Published: January 2021

Abstract
Cu plating bath for high-speed electrodeposition of Cu pillar was designed in consideration of a flat top morphology of pillar and a pillar height uniformity. An ideal polarization curve was assumed for the flat top morphology. To obtain the ideal polarization curve, an effect of organic additive concentration and solution agitation on the polarization curve were investigated. The basic bath components were optimized considering a Wagner number to improve pillar height uniformity. To confirm the pillar top morphology and the pillar height uniformity, a 300 mm diameter wafer was plated with Cu at 20 A/dm2. As a result, improved pillar top morphology and pillar height uniformity were obtained. The optimized plating bath was applied to the plating of large-size panel of 415 × 510 mm.
Optical Data Link Module for Data Transmission in Smart Catheters
Authors: Li Jian , Henneken Vincent , Louwerse Marcus , Dekker Ronald 
Published: January 2021

Abstract
We demonstrate a stand-alone optical data link module (ODLM) that fits in the limited space budget of smart imaging catheters. The module is based on an extension of the Flex-to-Rigid (F2R) technology platform for miniaturized system integration. The ODLM is a silicon-based interposer that comprises a commercially available Vertical Cavity Surface Emitting Laser (VCSEL), which has its electrical contacts and laser emitting spot on the same surface. With the flexible interconnects, the ODLM reroutes the flip-chipped VCSEL electrical contacts to the side that is perpendicular to the surface of the VCSEL. This enables the ODLM to be mounted on a flex-PCB and fit into the limited space in the distal tip of the smart catheter. An optical fiber that runs in parallel to the catheter shaft is inserted into the through-silicon hole (TSH) of the ODLM and self-aligned to the VCSEL for optical data transmission. The design of the ODLM and the F2R technology platform are introduced, and an ODLM demonstrator is fabricated and presented.
Wire Bonding: The Ultrasonic Bonding Mechanism
Authors: Levine Lee 
Published: January 2021

Abstract
Wire bonding is a welding process. During both ball and wedge bonding, wire and bond pad are massively deformed between the bond tool and the anvil of the bond pad or substrate. The dominant variables affecting deformation are ultrasonic energy, temperature, bond force and bond time. Deformation exposes new surface material that is clean and has not been exposed to atmospheric contamination and oxidation. As the new wire and bond pad surfaces mix, they form diffusion couples that grow and transform into the intermetallic weld nugget. The initial mixing is not at equilibrium in that it does not initially form the compounds described by the equilibrium phase diagram, but temperature and time very quickly allows diffusion to relax the initial mixture into the equilibrium phase diagram compounds. This paper will discuss the mechanisms behind the formation of ball and wedge bonds.
Gate Driver Design in a 1 μm SiC CMOS Process for Heterogeneous Integration Inside SiC Power Module
Authors: Abbasi Affan , Faruque Asif , Roy Sajib , Murphree Robert , Erlbacher Tobias , Mantooth Alan 
Published: January 2021

Abstract
In this paper, the design and implementation of a gate driver in SiC CMOS process is presented for heterogeneous integration (HI) inside the commercial SiC power module. The output stage of the gate driver circuit includes four-pull up (QP 1,2,3,4) and four-pull down (QN 1,2,3,4) transistors to vary current drive strength. The output stages are driven by tri-state buffer chains that are controlled by comparator based control circuits. The driver is tested over temperature up to 300°C. At higher temperatures, the peak drive current (under full strength with no external load) increases with the output swing remaining the same. Variation of the driver’s output pull-up and pull-down stage at higher load capacitance is also discussed in this paper. The driver circuit layout is optimized to utilize the maximum die area allowed by the process. The gate driver layout is 4.8mm × 4.8mm. The bond pads and layout orientation are configured for flip-chip packaging but can also be used for wire-bonding.
Factors associated with time to sputum culture conversion of rifampicin-resistant tuberculosis patients in Klaipeda, Lithuania in 2016-2019: a cohort study
Authors: Diktanas Saulius , Korotych Oleksandr , Sereda Yuliia , Gozalov Ogtay , Rubcova Olga , Achar Jay 
Published: January 2021

The global proportion of successful treatment outcomes of Multidrug-Resistant/Rifampicin-Resistant Tuberculosis (MDR/RR-TB) remains unacceptably low. Time to culture conversion is important in making treatment-related decisions and is used as an interim predictor of pulmonary MDR/RR-TB treatment success. No previous studies have been conducted to assess determinants of time to culture conversion for MDR/RR-TB patients in Lithuania. Secondary analysis of data of culture-positive MDR/RR-TB patients, treated in Republican Klaipeda Hospital between 1st July 2016 and 1st July 2019 was performed. Culture conversion was defined as two consecutive negative cultures on solid media submitted at least 30 days apart. Factors associated with culture conversion were estimated by crude and multivariable Cox regression accounting for competing risks. In total, 115 consecutive patients starting treatment were included in the study. Of them, the majority was male (86/115; 74.8%) with a mean age of 48 (standard deviation (SD) ±12) years and Human Immunodeficiency Virus (HIV) negative (105/115; 91.3%). Nearly two-thirds (72/115; 62.6%) had XDR (extensive drug resistance) or MDR/RR-TB with additional resistance to second-line injectables or fluoroquinolones. Of 115 culture-positive patients at baseline, 103 (89.6%) patients achieved culture conversion during 12 months of treatment. The median time to culture conversion was 1.1 months (interquartile range: 0.9-1.8). Patients aged ≥60 years compared with <40 years [adjusted hazard ration (aHR): 0.40, 95% confidence interval (CI): 0.18-0.86], smokers (aHR: 0.39, 95% CI: 0.2-0.73), patients with positive sputum smear microscopy at baseline (aHR: 0.40, 95% CI: 0.25-0.63), cavities on initial chest X-ray (aHR: 0.56, 95% CI: 0.35-0.88) and resistance to at least one fluoroquinolone drug (aHR: 0.52, 95% CI: 0.32-0.84) were slower to culture convert. In conclusion, we recommend providing additional counseling, treatment adherence interventions and scale up the use of new and repurposed TB drugs to patient groups at risk of worse interim treatment outcome: patients aged 60 and above, with resistance to fluoroquinolones, smear–positive, smokers, or with signs of extensive disease evident on initial chest radiography.
Factors associated with culture conversion among adults treated for pulmonary extensively drug-resistant tuberculosis during 2018-2019 in the Russian Federation: an observational cohort study
Authors: Russkikh Anastasiia , Korotych Oleksandr , Sereda Yuliia , Samoilova Anastasia , Achar Jay , Yedilbayev Askar , Dara Masoud , Vasilyeva Irina 
Published: January 2021

Treatment outcomes for Multidrug/Rifampicin-Resistant Tuberculosis (MDR/RR-TB) and Extensively Drug-Resistant Tuberculosis (XDR-TB) remain poor across the globe and in the Russian Federation. Treatment of XDR-TB is challenging for programmes and patients often resulting in low success rates and onward transmission of drug-resistant strains. Analysis of factors affecting culture conversion rate among XDR-TB patients may serve as a basis for optimization of treatment regimens. We conducted a retrospective cohort study using health records from 54 patients with pulmonary XDR-TB treated at a tertiary level facility in the Russian Federation. The study population included adult patients with culture-positive pulmonary XDR-TB who started treatment between 1 January 2018-30 June 2019. Culture conversion was defined as two consecutive negative cultures, collected at least 30 days apart. The date of sputum culture conversion was taken from the first of two consecutive negative sputum cultures fulfilling these criteria. We measured time to culture conversion using cumulative incidence functions accounting for competing risks and applied binary cause-specific Cox regressions to assess associated factors. Sputum culture conversion was recorded for 43 (79.6%) patients. Median time to culture conversion adjusted for competing risk of loss to follow up was 4 months [95% confidence interval (CI): 2–5]. The number of patients who had culture converted by treatment months 2, 4, and 6 were 12 (22%), 29 (54%) and 38 (70%) respectively. In unadjusted analysis, positive baseline sputum smear microscopy [hazard ratio (HR): 0.34, 95% CI: 0.18-0.66; p=0.001), hepatitis C (HR: 0.35, 95% CI: 0.14-0.89; p=0.023], and human immunodeficiency virus (HR: 0.30 95%, CI: 0.09-0.97; p=0.045), and receipt of fewer than 4 effective drugs in the treatment regimen (HR: 0.13, 95% CI: 0.03-0.60; p=0.009) were associated with delayed culture conversion. When compared to their combined use, patients receiving regimens with bedaquiline only (HR: 0.12, 95% CI: 0.03-0.49; p=0.003) or linezolid only (HR: 0.21, 95% CI: 0.06-0.69; p=0.010) were less likely to achieve timely culture conversion. Factors delaying sputum culture conversion should be considered in the management of patients with XDR-TB and considered by clinicians for regimen design and treatment strategies. Our study outlines the importance of simultaneous inclusion of bedaquiline and linezolid in treatment regimens for patients with XDR-TB to reduce time to sputum conversion and increase treatment success.
The effect of diagnostic assessment programs on the diagnosis and treatment of patients with lung cancer in Ontario, Canada
Authors: Habbous Steven , Khan Yasir , Langer Deanna L. , Kaan Melissa , Green Bo , Forster Katharina , Darling Gail , Holloway Claire M. B. 
Published: January 2021

INTRODUCTION:
Diagnostic assessment programs (DAPs) were implemented in Ontario, Canada, to improve the efficiency of the lung cancer care continuum. We compared the efficiency and effectiveness of care provided to patients in DAPs relative to usual care (non-DAPs).

METHODS:
Lung cancer patients diagnosed between 2014 and 2016 were identified from the Ontario Cancer Registry. Using administrative databases, we identified various health-care encounters 6 months before diagnosis until the start of treatment and compared utilization patterns, timing, and overall survival between DAP and non-DAP patients.

RESULTS:
DAP patients were younger (P < 0.0001), had fewer comorbidities (P = 0.0006), and were more likely to have early-stage disease (36% vs. 25%) than non-DAP patients. Although DAP patients had a similar time until diagnosis as non-DAP patients, the time until treatment was 8.5 days shorter for DAP patients. DAP patients were more likely to receive diagnostic tests and specialist consultations and less likely to have duplicate chest imaging. DAP patients were more likely to receive brain imaging. Among early-stage lung cancers, brain imaging was high (74% for DAP and 67% for non-DAP), exceeding guideline recommendations. After adjustment for clinical and demographic factors, DAP patients had better overall survival than non-DAP patients (hazard ratio [HR]: 0.79 [0.76–0.82]), but this benefit was lost after adjusting for emergency presentation (HR: 0.96 [0.92–1.00]). A longer time until treatment was associated with better overall survival.

CONCLUSION:
DAPs provided earlier treatment and better access to care, potentially improving survival. Quality improvement opportunities include reducing unnecessary or duplicate testing and characterizing patients who are diagnosed emergently.