Impact of multi-dimensional vibration trajectories on quality and failure modes in ultrasonic bonding

2019 ◽  
Vol 2019 (1) ◽  
pp. 000509-000514
Author(s):  
Reinhard Schemmel ◽  
Florian Eacock ◽  
Collin Dymel ◽  
Tobias Hemsel ◽  
Matthias Hunstig ◽  
...  

Abstract Ultrasonic joining is a common industrial process. To build electrical connections in the electronics industry, uni-axial and torsional ultrasonic vibration have been used to join different types of workpieces for decades. Many influencing factors like ultrasonic power, bond normal force, bond duration and frequency are known to have a high impact on bond quality and reliability. Multi-dimensional bonding has been investigated in the past to increase ultrasonic power and consequently bond strength. This contribution is focused on the comparison of circular, multi-frequency planar and uniaxial vibration trajectories used for ultrasonic bonding of copper pins on copper substrate. Bond quality was analyzed by shear tests, scanning acoustic microscopy and interface cross-sections.

Author(s):  
Péter Hegyi ◽  
László Dunai

A novel thin-walled structural system is under development which aims to utilise the beneficial effect of continuous bracing achieved by encasing CFS elements in ultra-lightweight-concrete. This paper deals with the experimental analysis of column-end joints. Altogether six types of end connection and four cross-sections were tested by 18 unbraced and 48 braced specimens. Based on the results four main zones of the load-displacement curves were defined which represent the behaviour of the different types. The failure modes and ultimate loads were identified and were found to be in close correlation with the results of previous tests on compression members. The experimental test helped to identify the main parameters of thin-walled column-end joints which affect the behaviour of the structural detail.


Author(s):  
S. Khadpe ◽  
R. Faryniak

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.


Author(s):  
Matthew J. Genge

Drawings, illustrations, and field sketches play an important role in Earth Science since they are used to record field observations, develop interpretations, and communicate results in reports and scientific publications. Drawing geology in the field furthermore facilitates observation and maximizes the value of fieldwork. Every geologist, whether a student, academic, professional, or amateur enthusiast, will benefit from the ability to draw geological features accurately. This book describes how and what to draw in geology. Essential drawing techniques, together with practical advice in creating high quality diagrams, are described the opening chapters. How to draw different types of geology, including faults, folds, metamorphic rocks, sedimentary rocks, igneous rocks, and fossils, are the subjects of separate chapters, and include descriptions of what are the important features to draw and describe. Different types of sketch, such as drawings of three-dimensional outcrops, landscapes, thin-sections, and hand-specimens of rocks, crystals, and minerals, are discussed. The methods used to create technical diagrams such as geological maps and cross-sections are also covered. Finally, modern techniques in the acquisition and recording of field data, including photogrammetry and aerial surveys, and digital methods of illustration, are the subject of the final chapter of the book. Throughout, worked examples of field sketches and illustrations are provided as well as descriptions of the common mistakes to be avoided.


Author(s):  
David J. Harvey ◽  
Anna-Janina Behrens ◽  
Max Crispin ◽  
Weston B. Struwe

AbstractNegative ion collision-induced dissociation (CID) of underivatized N-glycans has proved to be a simple, yet powerful method for their structural determination. Recently, we have identified a series of such structures with GalNAc rather than the more common galactose capping the antennae of hybrid and complex glycans. As part of a series of publications describing the negative ion fragmentation of different types of N-glycan, this paper describes their CID spectra and estimated nitrogen cross sections recorded by travelling wave ion mobility mass spectrometry (TWIMS). Most of the glycans were derived from the recombinant glycoproteins gp120 and gp41 from the human immunodeficiency virus (HIV), recombinantly derived from human embryonic kidney (HEK 293T) cells. Twenty-six GalNAc-capped hybrid and complex N-glycans were identified by a combination of TWIMS, negative ion CID, and exoglycosidase digestions. They were present as the neutral glycans and their sulfated and α2→3-linked sialylated analogues. Overall, negative ion fragmentation of glycans generates fingerprints that reveal their structural identity.


Fire Research ◽  
2016 ◽  
Author(s):  
Hélder D. Craveiro ◽  
João Paulo C. Rodrigues ◽  
Luís M. Laím

Cold-formed steel (CFS) profiles with a wide range of cross-section shapes are commonly used in building construction industry. Nowadays several cross-sections can be built using the available standard single sections (C, U, Σ, etc.), namely open built-up and closed built-up cross-sections. This paper reports an extensive experimental investigation on the behavior of single and built-up cold-formed steel columns at both ambient and simulated fire conditions considering the effect of restraint to thermal elongation. The buckling behavior, ultimate loads and failure modes, of different types of CFS columns at both ambient and simulated fire conditions with restraint to thermal elongation, are presented and compared. Regarding the buckling tests at ambient temperature it was observed that the use of built-up cross-sections ensures significantly higher values of buckling loads. Especially for the built-up cross-sections the failure modes were characterized by the interaction of individual buckling modes, namely flexural about the minor axis, distortional and local buckling. Regarding the fire tests, it is clear that the same levels of restraint used in the experimental investigation induce different rates in the generated restraining forces due to thermal elongation of the columns. Another conclusion that can be drawn from the results is that by increasing the level of restraint to thermal elongation the failure of the columns is controlled by the generated restraining forces, whereas for lower levels of restraint the temperature plays a more important role. Hence, higher levels of imposed restraint to thermal elongation will lead to higher values of generated restraining forces and eventually to lower values of critical temperature and time.


2018 ◽  
Vol 7 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Aleksandra Osika ◽  
Małgorzata Wistuba ◽  
Ireneusz Malik

Abstract The aim of the study is to reconstruct the development of landslide relief in the Kamienne Mountains (Central Sudetes, SW Poland) based on a DEM from LiDAR data. Analyses of relief and geological maps in ArcGIS 10.5 and of slope cross-sections in Surfer 14 allowed to distinguish different types of landslide relief, developed in latites and trachybasalts lying above claystones and mudstones. The types vary from small, poorly visible landslides to vast landslides with complex relief. They were interpreted as consecutive stages of geomorphic evolution of hillslope-valley topography of the study area. Two main schemes have been established which explain the development of landslide slopes in the Kamienne Mts: (1) upslope, from the base of the slope towards the mountain ridge and (2) downslope, beginning on the top of the mountain ridge. The direction of landslide development depends on the thickness of volcanic rocks in relation to underlying sedimentary rocks. When the latter appear only in the lowest part of the slope, landslides develop upslope. If sedimentary rocks dominate on the slope and volcanic rocks form only its uppermost part, landslides develop downslope. The results show that landsliding leads to significant modifications of relief of the study area, including complete degradation of mountain ridges.


PCI Journal ◽  
2021 ◽  
Vol 66 (2) ◽  
pp. 71-87
Author(s):  
Sandip Chhetri ◽  
Rachel A. Chicchi ◽  
Andrew E. N. Osborn

Very little experimental data have been published relating to the pullout capacity of prestressing strand lifting loops. To address this gap in knowledge, 13 pullout tests were conducted on strand lifting loops with 0.6 in. (15.24 mm) diameter, 270 ksi (1860 MPa) strand. Straight and bent orientations were tested for single loops at different embedment depths. Loops were embedded in 12 in. (304.8 mm) wide and 44 in. (1117.6 mm) deep concrete blocks and subjected to monotonic, static loading until failure. Marginal bond quality of the strand (18.2 kip [81 kN]), Mohs hardness (3.6), and concrete strength (3000 psi [20.7 MPa]) resulted in an average bond stress value of 400 psi (2758 kPa) at failure. Most tests exhibited pullout failure modes and adequate ductility. Three loops tested at 32 in. (812.8 mm) embedment with 6 in. (152.4 mm), 90-degree bends experienced brittle side-face blowout failures. These failures were due to inclination of the lifting, which led to a reduced edge distance. A safe uniform bond stress of 199 psi (1372 kPa) is recommended for 0.6 in. diameter strand.


2013 ◽  
Vol 2013 (1) ◽  
pp. 000001-000006
Author(s):  
F. Roozeboom ◽  
M. Smets ◽  
B. Kniknie ◽  
M. Hoppenbrouwers ◽  
G. Dingemans ◽  
...  

The current industrial process of choice for Deep Reactive Ion Etching (DRIE) of 3D features, e.g. Through-Silicon Vias (TSVs), Microelectromechanical Systems (MEMS), etc., is the Bosch process, which uses alternative SF6 etch cycles and C4F8-based sidewall passivation cycles in a time-sequenced mode. An alternative, potentially faster and more accurate process is to have wafers pass under spatially-divided reaction zones, which are individually separated by so-called N2-gas bearings ‘curtains’ of heights down to 10–20 μm. In addition, the feature sidewalls can be protected by replacing the C4F8-based sidewall passivation cycles by cycles forming chemisorbed and highly uniform passivation layers of Al2O3 or SiO2 deposited by Atomic Layer Deposition (ALD), also in a spatially-divided mode. ALD is performed either in thermal mode, or plasma-assisted mode in order to achieve near room-temperature processing. For metal filling of 3D-etched TSVs, or for deposition of 2D metal conductor lines one can use Laser-Induced Forward Transfer (LIFT) of metals. LIFT is a maskless, ‘solvent’-free deposition method, utilizing different types of pulsed lasers to deposit thin material (e.g. Cu, Au, Al, Cr) layers with μm-range resolution from a transparent carrier (ribbon) onto a close-by acceptor substrate. It is a dry, single-step, room temperature process in air, suitable for different types of interconnect fabrication, e.g. TSV filling and redistribution layers (RDL), without the use of wet chemistry.


Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Yong Liu ◽  
Huidong Zhang ◽  
Pathegama Gamage Ranjith ◽  
Jianping Wei ◽  
Xiaotian Liu

The existing erosion models of abrasive gas jet tend to neglect the effects of the rebounding abrasive. To address this shortcoming, abrasive wear tests were conducted on limestone by using an abrasive gas jet containing different types of particles and with different standoff distances. The results indicate that erosion pits have the shape of an inverted cone and a hemispherical bottom. An annular platform above the hemispherical bottom connects the bottom with the side of the pit. The primary cause of the peculiar pit shape is the flow field geometry of the gas jet with its entrained particles. There is an annular region between the axis and boundary of the abrasive gas jet, and it contains no abrasive. Particles swirling around the axis form a hemispherical bottom. After rebounding, the abrasive with the highest velocity enlarges the diameters of both the hemispherical bottom and erosion pit and induces the formation of an annular platform. The surface features of different areas of the erosion pit are characterized using a scanning electron microscope (SEM). It can be concluded that the failure modes for different locations are different. The failure is caused by an impact stress wave of the incident abrasive at the bottom. Plastic deformation is the primary failure mode induced by rebounding particles at the sides of the hemispherical bottom. The plastic deformation induced by the incident abrasive and fatigue failure induced by the rebounding abrasive are the primary failure modes on the annular platform. Fatigue failure induced by rebounding particles is the primary mode at the sides of the erosion pits. The rock failure mechanism that occurs for particles with different hardness is the same, but the rock damaged by the hard abrasive has a rougher surface.


2015 ◽  
Vol 62 (3-4) ◽  
pp. 101-119 ◽  
Author(s):  
Wojciech Artichowicz ◽  
Dzmitry Prybytak

AbstractIn this paper, energy slope averaging in the one-dimensional steady gradually varied flow model is considered. For this purpose, different methods of averaging the energy slope between cross-sections are used. The most popular are arithmetic, geometric, harmonic and hydraulic means. However, from the formal viewpoint, the application of different averaging formulas results in different numerical integration formulas. This study examines the basic properties of numerical methods resulting from different types of averaging.


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