Influence of Bonding Pressure on the Mechanical Properties of Copper Bumps

Bonding Temperature ◽

Threshold Value ◽

Bonding Pressure ◽

Thermocompression Bonding ◽

The Individual ◽

Thermocompression bonding is one of the key ways to form interconnections in many hetegrogeneous devices. The quality of metallic joints formed using thermocompression is predominantly determined by the bonding temperature and pressure. In order to achieve a strong and reliable joint, metallic joints in particular copper, which has an oxidative nature, require a high bonding temperature (> 300 °C). However, thermomechanical-related stresses induced during bonding can compromise the performance of the interconnections in the long term. Thus, one way to manage this is to lower the bonding temperature used in forming the interconnections. In this study, copper-copper bonding is successfully demonstrated at a bonding temperature of 80 °C. In order to better understand the effect of bonding pressure on the joint’s performance, the mechanical properties of the individual bulk copper bumps are evaluated using the nanoindentation system. Studies are conducted on the bulk copper bumps subjected to different bonding pressures. Their corresponding yield strength and hardness results are then determined. It is observed that as the applied bonding pressure increases, the mechanical properties of the bulk copper bump reach a certain threshold value and beyond which, properties start to degrade. The microstructure and grain sizes of the copper bumps are also analyzed using the electron backscatter diffraction.

Correlation of Strain Path, Texture, Twinning, and Mechanical Properties in Twinning-Induced Plasticity Steel during Wire Drawing

Materials ◽

10.3390/ma13102250 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2250 ◽

Cited By ~ 1

Author(s):

Joong-Ki Hwang

Keyword(s):

Mechanical Properties ◽

Strain Path ◽

Steel Wire ◽

Effective Strain ◽

Metal Flow ◽

Wire Drawing ◽

Surface Areas ◽

The Wire ◽

The effect of changing the strain path on texture development, twin kinetics, and mechanical properties in twinning-induced plasticity steel was investigated to understand twinning behavior in more detail. Among the various plastic deformation processes, the wire drawing process was selected to achieve the aims of the study. Specimens of cold-drawn TWIP steel wire under the same effective strain but with different crystallographic textures were successfully fabricated using the effect of the wire drawing direction. Electron backscatter diffraction results showed that the drawn wires using both unidirectional (UD) and reverse-directional (RD) wire drawing processes were characterized as duplex fiber textures of major <111> and minor <100>. It was found that the RD wire had a higher fraction of <111> component at both the center and surface areas compared to the UD wire, because the metal flow of the RD wire was beneficial for the development of a <111> orientation. The pronounced <111> crystallographic orientation of the RD wire activated the twinning rate and geometrically necessary dislocation density, leading to an increase in strength but a decrease in ductility. The strain path is as important as the amount of strain for strengthening the materials, especially those that are deformed by twinning.

The Effect of Simultaneous Si and Ti/Mo Alloying on High-Temperature Strength of Fe3Al-Based Iron Aluminides

Molecules ◽

10.3390/molecules25184268 ◽

2020 ◽

Vol 25 (18) ◽

pp. 4268

Author(s):

Věra Vodičková ◽

Martin Švec ◽

Pavel Hanus ◽

Pavel Novák ◽

Antonín Záděra ◽

...

Keyword(s):

Phase Composition ◽

High Temperature ◽

Yield Stress ◽

Xrd Analysis ◽

Iron Aluminides ◽

High Temperature Strength ◽

X Ray Diffraction ◽

The effect of phase composition and morphology on high-temperature strength in the compression of Fe-Al-Si-based iron aluminides manufactured by casting was investigated. The structure and high-temperature strength in the compression of three alloys—Fe28Al5Si, Fe28Al5Si2Mo, and Fe28Al5Si2Ti—were studied. Long-term (at 800 °C for 100 h) annealing was performed for the achievement of structural stability. The phase composition and grain size of alloys were primarily described by means of scanning electron microscopy equipped with energy dispersive analysis and Electron Backscatter Diffraction (EBSD). The phase composition was verified by X-ray diffraction (XRD) analysis. The effect of Mo and Ti addition as well as the effect of long-term annealing on high-temperature yield stress in compression were investigated. Both additives—Mo and Ti—affected the yield stress values positively. Long-term annealing of Fe28Al5Si-X iron aluminide alloyed with Mo and Ti deteriorates yield stress values slightly due to grain coarsening.

Optimising Epilepsy Therapy – Searching for the Evidence – Looking Beyond the Data

European Neurological Review ◽

10.17925/enr.2015.10.02.164 ◽

2015 ◽

Vol 10 (2) ◽

pp. 164

Author(s):

Mar Carreño ◽

Eugen Trinka ◽

Martin Holtkamp ◽

◽

...

Keyword(s):

Refractory Epilepsy ◽

Study Data ◽

Type D ◽

Epilepsy Therapy ◽

Suitable Treatment ◽

Type C ◽

The Individual ◽

The Devil

There is now an extensive range of anti-epileptic drugs (AEDs) available including older established treatments and a newer generation of medications. The choice of drugs and what constitutes optimal therapy, however, is unclear due to limitations in the data supporting their use, particularly among the newer treatments. In clinical trials of monotherapy, a treatment is required to show only non-inferiority to another benchmark treatment. In trials of polytherapy, comparisons are limited to placebo. It is therefore necessary to look beyond the study data and consider other parameters to ascertain the most suitable treatment for the individual patient. Available evidence suggests that efficacy is similar among most AEDs, but this does not mean they are all the same. Some show efficacy in early and refractory epilepsy and some improve depression and quality of life (QOL) in epilepsy. AEDs are associated with a range of adverse events (AEs) that can limit their usefulness. AE classifications include type A (augmented and dose related) including tiredness, fatigue, insomnia, dizziness, vertigo, imbalance, ataxia, tremor and cognitive impairment; type B (bizarre and idiosyncratic) including various hypersensitivity reactions; type C (chronic long-term toxicity) including hirsutism, alopecia, weight gain and obesity; and type D (teratogenesis and carcinogenesis). The newer AEDs have been more thoroughly assessed for AEs than older drugs and risks are better understood. In AED safety, it is not better to follow a policy of ‘better the devil you know’ but rather to carefully monitor AE incidence and be prepared to switch drugs to improve tolerability and avoid non-compliance and treatment failure.

Crystal chemistry of clinker relicts from aged cementitious materials

Journal of Applied Crystallography ◽

10.1107/s1600576714018287 ◽

2014 ◽

Vol 47 (5) ◽

pp. 1626-1637 ◽

Cited By ~ 1

Author(s):

Michele Secco ◽

Luca Peruzzo ◽

Laurie Palasse ◽

Gilberto Artioli ◽

Alberto Viani ◽

...

Keyword(s):

Microstructural Analysis ◽

Chemical Properties ◽

Cementitious Materials ◽

Operating Conditions ◽

General Tendency ◽

Hydration Kinetics ◽

Definition Of ◽

Despite the general tendency to consider Portland cement virtually fully hydrated within a few years, the occurrence of non-reacted clinker phases in cementitious materials that are several decades old is rather common. In this work, the integration of microstructural analysis by scanning electron microscopy and quantitative microchemical and micromineralogical characterization techniques, such as electron microprobe analysis and electron backscatter diffraction, allowed the definition of the crystal-chemical properties of partially hydrated cement residuals within different types of aged cementitious materials. The results on several clinker relicts show that the calcium silicate phases are transformed systematically and pervasively by hydration reactions, whereas the aluminate and ferrite phases do frequently persist in the anhydrous state. These relict phases may be distinguished through their peculiar chemical, mineralogical and textural features. These observations raise interesting questions concerning the long-term hydration kinetics of clinker phases and the durability behaviour of cementitious materials in operating conditions.

An improved NO<sub>2</sub> retrieval for the GOME-2 satellite instrument

Atmospheric Measurement Techniques ◽

10.5194/amt-4-1147-2011 ◽

2011 ◽

Vol 4 (6) ◽

pp. 1147-1159 ◽

Cited By ~ 101

Author(s):

A. Richter ◽

M. Begoin ◽

A. Hilboll ◽

J. P. Burrows

Keyword(s):

Signal To Noise Ratio ◽

Bare Soil ◽

Satellite Observations ◽

Spectral Signature ◽

Data Set ◽

Good Consistency ◽

The Individual ◽

High Pass

Abstract. Satellite observations of nitrogen dioxide (NO2) provide valuable information on both stratospheric and tropospheric composition. Nadir measurements from GOME, SCIAMACHY, OMI, and GOME-2 have been used in many studies on tropospheric NO2 burdens, the importance of different NOx emissions sources and their change over time. The observations made by the three GOME-2 instruments will extend the existing data set by more than a decade, and a high quality of the data as well as their good consistency with existing time series is of particular importance. In this paper, an improved GOME-2 NO2 retrieval is described which reduces the scatter of the individual NO2 columns globally but in particular in the region of the Southern Atlantic Anomaly. This is achieved by using a larger fitting window including more spectral points, and by applying a two step spike removal algorithm in the fit. The new GOME-2 data set is shown to have good consistency with SCIAMACHY NO2 columns. Remaining small differences are shown to be linked to changes in the daily solar irradiance measurements used in both GOME-2 and SCIAMACHY retrievals. In the large retrieval window, a not previously identified spectral signature was found which is linked to deserts and other regions with bare soil. Inclusion of this empirically derived pseudo cross-section significantly improves the retrievals and potentially provides information on surface properties and desert aerosols. Using the new GOME-2 NO2 data set, a long-term average of tropospheric columns was computed and high-pass filtered. The resulting map shows evidence for pollution from several additional shipping lanes, not previously identified in satellite observations. This illustrates the excellent signal to noise ratio achievable with the improved GOME-2 retrievals.

Microstructure and Mechanical Properties of Ti Cold-Spray Splats Determined by Electron Channeling Contrast Imaging and Nanoindentation Mapping

Microscopy and Microanalysis ◽

10.1017/s1431927615000240 ◽

2015 ◽

Vol 21 (3) ◽

pp. 570-581 ◽

Cited By ~ 21

Author(s):

Dina Goldbaum ◽

Richard R. Chromik ◽

Nicolas Brodusch ◽

Raynald Gauvin

Keyword(s):

Mechanical Properties ◽

Cold Spray ◽

Substrate Material ◽

Contrast Imaging ◽

Electron Channeling ◽

Metallurgical Bonding ◽

Resolution Electron ◽

Backscatter Diffraction ◽

The Impact

AbstractCold spray is a thermo-mechanical process where the velocity of the sprayed particles affects the deformation, bonding, and mechanical properties of the deposited material, in the form of splats or coatings. At high strain rates, the impact stresses are converted into heat, a phenomenon known as adiabatic shear, which leads to grain re-crystallization. Grain re-crystallization and growth are shown to have a direct impact on the mechanical properties of the cold-sprayed material. The present study ties the microstructural features within the cold-sprayed Ti splats and the substrate to the bonding mechanism and mechanical properties. High-resolution electron channeling contrast imaging, electron backscatter diffraction mapping, and nanoindentation were used to correlate the microstructure to the mechanical properties distribution within the titanium cold-spray splats. The formation of nanograins was observed at the titanium splat/substrate interface and contributed to metallurgical bonding. An increase in grain re-crystallization within the splat and substrate materials was observed with pre-heating of the substrate. In the substrate material, the predominant mechanism of deformation was twinning. A good relationship was found between the hardness and distribution of the twins within the substrate and the size distribution of the re-crystallized grains within the splats.

Decoupling the Impacts of Strain Rate and Temperature on TRIP in a Q&P Steel

JOM ◽

10.1007/s11837-021-05039-5 ◽

2022 ◽

Author(s):

Christopher B. Finfrock ◽

Diptak Bhattacharya ◽

Brady N. L. McBride ◽

Trevor J. Ballard ◽

Amy J. Clarke ◽

...

Keyword(s):

Martensitic Transformation ◽

Strain Rate ◽

Strain Hardening ◽

Dislocation Slip ◽

Transformation Induced Plasticity ◽

High Strain Rate Deformation ◽

The Individual ◽

Backscatter Diffraction ◽

Strain Hardening Rate

AbstractThe individual effects of strain rate and temperature on the strain hardening rate of a quenched and partitioned steel have been examined. During quasistatic tests, resistive heating was used to simulate the deformation-induced heating that occurs during high-strain-rate deformation, while the deformation-induced martensitic transformation was tracked by a combination of x-ray and electron backscatter diffraction. Unique work hardening rates under various thermal–mechanical conditions are discussed, based on the balance between the concurrent dislocation slip and transformation-induced plasticity deformation mechanisms. The diffraction and strain hardening data suggest that the imposed strain rate and temperature exhibited dissonant influences on the martensitic phase transformation. Increasing the strain rate appeared to enhance the martensitic transformation, while increasing the temperature suppressed the martensitic transformation.

Personalization of the use of non-steroidal anti-inflammatory drugs for musculoskeletal diseases. Resolution on the results of the Meeting of Experts of December 13, 2017

Medical Council ◽

10.21518/2079-701x-2018-18-76-84 ◽

2018 ◽

pp. 76-84 ◽

Cited By ~ 1

Author(s):

A. E. Karateev ◽

A. M. Lila ◽

I. S. Dydykina ◽

P. R. Kamchatnov ◽

S. O. Mazurenko ◽

...

Keyword(s):

Musculoskeletal Diseases ◽

Modern Medicine ◽

Individual Characteristics ◽

Analgesic Therapy ◽

Acute Pain Therapy ◽

Inflammatory Drugs ◽

The Individual ◽

Key Aspects

The personalization of therapy is one of the innovative approaches gaining an increasingly strong foothold in modern medicine, implying an individual approach to each patient, taking into account the individual characteristics of the patient and the specific clinical case. This same standpoint of personified therapy should be used to plan rational analgesic therapy, the most important component of managing patients with the most common and socially significant diseases, with conditions that have a significant impact on the patient’s quality of life and worsen the course of concomitant diseases. The Meeting of Experts of different specialties such as rheumatologists, neurologists, cardiologists and clinical pharmacologists considered the key aspects of the prescription of NSAIDs, the most widely used class of painkillers, including those used for the relief of musculoskeletal pain. It was noted that when choosing NSAIDs, the practitioner should take into account the diagnosis, the planned duration of analgesic therapy, the intensity of pain, medical history data, the presence of comorbid diseases and risk factors for drug complications. There are different types of NSAIDs, some of which are most useful for urgent acute pain therapy (eg, ketoprofen), while others are most suitable for long-term pain management in chronic diseases (eg, etoricoxib). In any case, the practitioner should take into account the priority of patient safety and pay the utmost attention to the prevention of NSAIDassociated complications, and also keep in mind the duration of the specific drug administration permitted by the patient information leaflet. It was also noted that the launch of a new generic etoricoxib (Kostarox®) expands the possibilities of analgesic therapy for the Russian practitioners.

Micro-level Clearance Punching on NGO Electrical Steel

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4047046 ◽

2020 ◽

Vol 142 (8) ◽

Author(s):

Zhenglong Fang ◽

Keisuke Nagato ◽

Tomohito Shimura ◽

Masato Murakami ◽

Masayuki Nakao

Keyword(s):

Plastic Strain ◽

Electrical Steel ◽

Dimensional Accuracy ◽

Magnetic Core ◽

Micro Level ◽

Shear Speed ◽

Backscatter Diffraction ◽

Cut Surface

Abstract Non-grain-oriented electrical steel lamination is a critical component for the magnetic core. Punching such steel sheet with a large shear region, a low burr and small rollover is required to ensure accuracy. Densely packed grain deformation and plastic strain near cut surface are generally accompanied which detrimentally influence magnetic properties. In this study, micro-clearance (CL: 1 and 5 µm) punching of electrical silicon steel was conducted to investigate the influences of punching speed, micro-clearance, and counterforce on dimensional accuracy and microstructural changes. Electron backscatter diffraction analysis was performed to investigate the microstructural characteristics and detailed texture of specimens produced by shear speeds of 100, 260, and 600 mm/s with and without applied counterforce. Rollover height was found to be significantly reduced at a shear speed of 260 mm/s with applied counterforce under 1 µm clearance punching. The applications of counterforce and higher speed both significantly increased grain deformation, although the dimensional accuracy was improved. Grain conditions and the quality of cut surface were compared for different punching conditions to advance the understanding on the correlations between dimensional accuracy, grain deformation, and plastic strain.

Sunspot area catalog revisited: Daily cross-calibrated areas since 1874

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037547 ◽

2020 ◽

Vol 640 ◽

pp. A78 ◽

Cited By ~ 3

Author(s):

Sudip Mandal ◽

Natalie A. Krivova ◽

Sami K. Solanki ◽

Nimesh Sinha ◽

Dipankar Banerjee

Keyword(s):

Sunspot Area ◽

The Other ◽

Royal Greenwich Observatory ◽

Individual Group ◽

Cross Calibration ◽

The Individual ◽

Temporal Coverage ◽

Final Composite

Context. Long and consistent sunspot area records are important for understanding long-term solar activity and variability. Multiple observatories around the globe have regularly recorded sunspot areas, but such individual records only cover restricted periods of time. Furthermore, there are systematic differences between these records and require cross-calibration before they can reliably be used for further studies. Aims. We produce a cross-calibrated and homogeneous record of total daily sunspot areas, both projected and corrected, covering the period between 1874 and 2019. In addition, we generated a catalog of calibrated individual group areas for the same period. Methods. We compared the data from nine archives: Royal Greenwich Observatory (RGO), Kislovodsk, Pulkovo, Debrecen, Kodaikanal, Solar Optical Observing Network (SOON), Rome, Catania, and Yunnan Observatories, covering the period between 1874 and 2019. Cross-comparisons of the individual records were done to produce homogeneous and inter-calibrated records of daily projected and corrected areas. As in earlier studies, the basis of the composite is formed by the data from RGO. After 1976, the only datasets used are those from Kislovodsk, Pulkovo, and Debrecen observatories. This choice was made based on the temporal coverage and the quality of the data. While there are still 776 days missing in the final composite, these remaining gaps could not be filled with data from the other archives as the missing days lie either before 1922 or after 2016 and none of the additional archives cover these periods. Results. In contrast to the SOON data used in previous area composites for the post-RGO period, the properties of the data from Kislovodsk and Pulkovo are very similar to those from the RGO series. They also directly overlap the RGO data in time, which makes their cross-calibration with RGO much more reliable. Indeed, comparing our area catalog with previous such composites, we find improvements both in data quality and coverage. We also computed the daily Photometric Sunspot Index, which is widely used, for example, in empirical reconstructions of solar irradiance.