On Measurement of Effective Silicon Backend Strength Using Bump Pull/Shear Techniques

2005 ◽  
Author(s):  
Sandeep Sane ◽  
Shalabh Tandon ◽  
Biju Chandran ◽  
Tsgereda Alazar ◽  
Leonard R. Sorenson
Keyword(s):  
Failure Modes ◽  
Tensile Force ◽  
Lead Free ◽  
Stress Exposure ◽  
Process Variables ◽  
First Case ◽  
Repeatability And Reproducibility ◽  
The Impact ◽  
Low K

Integrating a low-K ILD layer within silicon is key to reducing RC delays. However, low-K ILD materials typically have low mechanical strength, making their incorporation with lead free interconnects an industry-wide challenge. It is well known that conversion to lead free first level interconnects increases die backend stresses due to the higher melting temperature and increased solder stiffness. The paper will focus on the measurement of the effective silicon backend strength after subjecting the dice to different fabrication and assembly steps. The effective strength will also be evaluated post reliability stress exposure to eventually understand the life of these films. The paper will describe how a commercially available Dage 4000 tool was modified for this application. Bump pull was carried out using a 100μm tweezers, while bump shear used 1mil (25.4μm) wide stylus. Static and dynamic calibration was first carried out to ensure repeatability and reproducibility of the results. Peak force and failure modes were used as metrics to compare the effectiveness of different experimental legs. Traditional failure analysis approach of mechanical polishing, or when needed, use of FIB for sample preparation, with subsequent SEM/EDX analysis was utilized to understand the failure mechanism. Data suggests that shear and pull lead to different failure modes. Bump shear mainly led to failure at the bump/polyimide interface and did not necessarily correspond to the weakest layer or interface in the silicon backend. Whereas bump-pull, which applies tensile force to the stack up, lead to failures in the weakest layer, typically the low-K ILD, in the silicon backend. Hence, bump pull provided the advantage over shear as it allowed evaluation of the weakest interface in the stack up. Two case studies are discussed to demonstrate on how bump pull/shear metrologies were used to understand the impact of different assembly/FAB process variables and highly accelerated steam test (HAST) reliability stress on silicon backend strength. First case study shows influence of assembly flux on silicon backend strength, while second case study describes impact of HAST on different FAB backend processes.

scholarly journals Cable Tensile Forces Associated to Winch Design in Tethered Harvesting Operations: A Case Study from the Pacific North West

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 827
Author(s):  
Omar Mologni ◽  
Eric D. T. Nance ◽  
C. Kevin Lyons ◽  
Luca Marchi ◽  
Stefano Grigolato ◽  
...  
Keyword(s):  
Endurance Limit ◽  
Tensile Force ◽  
Force Analysis ◽  
North West ◽  
The Pacific ◽  
Work Tasks ◽  
Tensile Forces ◽  
System Activation ◽  
The Impact

Cable tensile forces in winch-assist harvesting have been investigated in order to assess the safety concerns of the technology. However, the literature is lacking, particularly in regards to the impact of winch design. In this study, a Summit Winch Assist tethering a feller-director on ground slopes up to 77% was monitored for four days. The cable tensile forces were simultaneously recorded at the harvesting and anchor machine at a frequency of 100 Hz. Cameras and GNSS devices enabled a time study of the operations and the recording of machine positions. Winch functionality and design were disclosed by the manufacturer and used for the interpretation of the results. The cable tensile forces reached 296 kN at the harvesting machine and 260 kN at the anchor machine. The slow negotiation of obstacles while moving downhill recorded the highest peaks, mainly due to threshold settings of the winch in the brake system activation. Lower but significant peaks were also recorded during stationary work tasks. The peaks, however, were limited to a few events and never exceeded the endurance limit of the cable. Overall, the study confirmed recent findings in cable tensile force analysis of active winch-assist operations and provided evidence of the underlaying mechanisms that contribute to cable tensile forces.

A Conceptual Framework for Evaluating Joint Venture Opportunities between Hospitals and Physicians

1989 ◽  
Vol 2 (3) ◽  
pp. 204-212 ◽  
Author(s):  
Carol K. Jacobson
Keyword(s):  
Conceptual Framework ◽  
Joint Venture ◽  
Transaction Cost Economics ◽  
Regulatory Environment ◽  
Strategic Decisions ◽  
Health Care Managers ◽  
Subsequent Formation ◽  
First Case ◽  
The Impact

A Conceptual Framework for Evaluating Joint Venture Opportunities Between Hospitals and Physicians This paper reviews the changes in the competitive and regulatory environment and examines the impact of those changes on the relationships between hospitals and physicians. Transaction cost economics (TCE) provides a conceptual framework for examining the emergence of closer linkages between hospitals and physicians than the traditional independent hospital and medical staff organisations. TCE predicts that as investments in support of transactions become more specialised, closer linkages are more efficient. To illustrate, two case studies of successful hospital-physician joint ventures are presented. The first case study describes a joint venture between hospitals and physicians to purchase durable medical equipment. The second case describes the breakdown of an informal arrangement and the subsequent formation of a joint venture to organise a clinical programme. The discussion reports the rationale for choosing these structural arrangements and their key features, pointing out how TCE would account for the decision to establish a joint venture. The conclusion discusses the implications of this argument for the strategic decisions of health care managers.

Ancient Bug Bites on Ancient Plants Record Forest Ecosystem Response to Environmental Perturbations

2013 ◽  
Vol 19 ◽  
pp. 157-174 ◽  
Author(s):  
Ellen D. Currano
Keyword(s):  
Trophic Interactions ◽  
Insect Herbivory ◽  
Fossil Flora ◽  
Local Perturbation ◽  
Insect Damage ◽  
Ecosystem Response ◽  
Insect Feeding ◽  
First Case ◽  
The Impact

Leaf-compression fossils with insect feeding traces are unique in providing rich, direct evidence of two levels in a fossil food web. Plant-insect associations dominate terrestrial trophic interactions, emphasizing the need to understand their ecological and evolutionary history. This paper first discusses methods of recognizing insect herbivore damage on fossil leaves and quantifying fossil insect herbivory. By conducting an unbiased insect damage census, damage frequency (percent of leaves with insect feeding damage), percent of leaf surface area removed by insects, and damage diversity (the number of discrete damage morphotypes, or DTs, found on a fossil flora or individual host plant) can all be measured. Three examples of responses of past plant-insect trophic interactions to environmental stresses are examined. In the first case study, late Oligocene fossil floras from Ethiopia document forest response to local perturbation and key characteristics to recognize disturbance in the plant fossil record. The second case study considers the terrestrial ecosystem response to the catastrophic global perturbation at the Cretaceous–Paleogene boundary. In the third case study, the impact of past global warming events—including the Paleocene–Eocene Thermal Maximum—on insect herbivory is discussed. Productive avenues for further research include: insect damage studies conducted outside the North American Cretaceous and Paleogene, actualistic and taphonomic studies of insect herbivory, and tighter collaboration across paleobotany, paleoentomology, botany, and entomology.

E pluribus unum? Language diversity and the harmonization of company law in the European Union

2019 ◽  
Vol 26 (5) ◽  
pp. 669-690
Author(s):  
Federico M Mucciarelli
Keyword(s):  
European Union ◽  
Case Studies ◽  
Company Law ◽  
Language Diversity ◽  
The European Union ◽  
Freedom Of Establishment ◽  
First Case ◽  
Definition Of ◽  
The Impact

This work addresses the impact of language diversity and nation-specific doctrinal structures on harmonized company law in the EU. With this aim, two emblematic case studies will be analysed. The first case study is related to the definition of ‘merger’ adopted in the Company Law Directive 2017/1132 (originally in the Third Company Law Directive and the Cross-Border Merger Directive); by relying on the example of the SEVIC case decided by the Court of Justice of the European Union (CJEU), it will be shown that scholars’ and courts’ conception of the definition of ‘merger’ varies according to own domestic doctrinal structures. The second case study is related to the notion of ‘registered office’, which is key for establishing the scope of several harmonizing provisions and the freedom of establishment; this paper analyses terminological fluctuations across language versions of EU legislation and the impact of domestic taxonomies and legal debates upon the interpretation of these notions. These case studies show that company law concepts, despite their highly technical nature, are influenced by discourse constructions conducted within national interpretative communities, and by the language used to draft statutory instruments and discuss legal issues. The task of the CJEU is to counterbalance these local tendencies, and yet it is unlikely that doctrinal structures, rooted in national languages and legal cultures, will disappear.

Probability of Uncontrolled External Leakage During the Production Phase of a Subsea Well

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
André L. R. Alves ◽  
T. A. Netto
Keyword(s):  
Failure Modes ◽  
Base Case ◽  
Component Reliability ◽  
Production Phase ◽  
Distribution Parameters ◽  
Common Cause Failures ◽  
Integrity Management ◽  
Closed Position ◽  
The Impact

Abstract This work presents a methodology for evaluating the uncontrolled external leakage probability of a subsea well during the production phase. Based on a barrier diagram, an algorithm for possible leak path identification is proposed, considering different operation modes: gas lift operation, free-flowing, or well closed at the subsea Christmas tree. Considering the equivalency between these paths and the minimum cut sets from a fault tree modeling, the uncontrolled external leakage probability is calculated using the upper bound approximation. The effect of common cause failures is considered for the failure mode fail-to-close-valve. The instantaneous availability function of each component is considered. Non-repairable, repairable, and periodically tested items are used. Probability distribution parameters are estimated in order to make a case study. The failure rate functions determined are used as input for the proposed model, regarding the following failure modes: fail-to-close, external-leakage, and internal-leakage at the closed position. Finally, failure probability results and sensitivity analysis are demonstrated for a base case study. Parameters like time between tests, inspections, and component reliability are varied in order to identify the impact on the uncontrolled external leakage probability. The main objective of the proposed methodology is to support decision-making on the well integrity management system during the production phase of a subsea well. To this end, actual and reliable input data should be considered.

Where Fossils Dare and Males Matter: combined morphological and molecular analysis untangles the evolutionary history of the spider ant genus Leptomyrmex Mayr (Hymenoptera : Dolichoderinae)

2017 ◽  
Vol 31 (6) ◽  
pp. 765 ◽  
Author(s):  
Phillip Barden ◽  
Brendon Boudinot ◽  
Andrea Lucky
Keyword(s):  
Evolutionary History ◽  
Morphological Evolution ◽  
Sister Group ◽  
Morphological Characters ◽  
Fossil Material ◽  
First Case ◽  
History Of ◽  
The Impact ◽  
Surprising Discovery

The distinctive ant genus Leptomyrmex Mayr, 1862 had been thought to be endemic to Australasia for over 150 years, but enigmatic Neotropical fossils have challenged this view for decades. The present study responds to a recent and surprising discovery of extant Leptomyrmex species in Brazil with a thorough evaluation of the Dominican Republic fossil material, which dates to the Miocene. In the first case study of direct fossil inclusion within Formicidae Latreille, 1809, we incorporated both living and the extinct Leptomyrmex species. Through simultaneous analysis of molecular and morphological characters in both Bayesian and parsimony frameworks, we recovered the fossil taxon as sister-group to extant Leptomyrmex in Brazil while considering the influence of taxonomic and character sampling on inferred hypotheses relating to tree topology, biogeography and morphological evolution. We also identified potential loss of signal in the binning of morphological characters and tested the impact of parameterisation on divergence date estimation. Our results highlight the importance of securing sufficient taxon sampling for extant lineages when incorporating fossils and underscore the utility of diverse character sources in accurate placement of fossil terminals. Specifically, we find that fossil placement in this group is influenced by the inclusion of male-based characters and the newly discovered Neotropical ‘Lazarus taxon’.

Coupled versus uncoupled optimal solutions for thermal and dynamic problems in spacecraft atmospheric flight

2016 ◽  
Vol 13 (1) ◽  
pp. 53-60
Author(s):  
Antonio Mazzaracchio
Keyword(s):  
Orbital Plane ◽  
Operating Mode ◽  
Heat Shield ◽  
Dynamic Problems ◽  
Content Type ◽  
Orbital Maneuvers ◽  
First Case ◽  
Plane Change ◽  
The Impact

Purpose This paper aims to address a significant issue related to the coupled and uncoupled treatment of the thermal and dynamic problems in the optimization of aeroassisted orbital maneuvers and the simultaneous optimal sizing of the associated heat shields. The literature generally focuses on decoupled treatments that reduce the computational load; in this manner, consequently, a decrease in the representativity of the solution manifests. The general operating mode first optimizes the trajectory and subsequently defines the optimal heat shield design based on that trajectory. Design/methodology/approach This paper analyzes the impact of both treatments on the evaluation of the convenience of an aeroassisted maneuver with respect to an equivalent purely propulsive exoatmospheric maneuver in relation to the achievable total mass savings of the propellant and the heat shield. Two case studies are analyzed via an optimization methodology that references genetic algorithms: the first case study is related to an aerobraking maneuver and the second case study is related to an orbital plane change. Findings The results demonstrate that the adoption of decoupling produces conservative solutions, i.e. unfavorable estimates, with a lower level of convenience of the aeroassisted technique compared to equivalent purely propulsive exoatmospheric maneuvers. Originality/value This type of analysis can provide an appropriate discernment criterion for the selection of the modus operandi based on the available computational power and the desired level of representativity.

scholarly journals Islamic Authority Figures and Their Religioscapes in Indonesia

Teosofia ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 37-58
Author(s):  
Claudia Seise
Keyword(s):  
Social Space ◽  
Religious Practice ◽  
Religious Authority ◽  
The People ◽  
First Case ◽  
Authority Figures ◽  
Methodological Tool ◽  
Learning Institutions ◽  
The Impact

In this article I argue that religious authority figures in Indonesia form the core of any given religioscape. A religioscape is a dynamic social space where one religious practice or religious interpretation is predominant. At the same time religious authority figures are influenced by the historically grown religioscape in which they live, and this mutual process affects all the people living in it. With the example of three religious authority figures and their respective learning institutions in Indonesia, I aim to illustrate how Muslim personalities influence and shape the religioscape that surrounds them. The first case study is grounded in the mystic Islam found in Yogyakarta, the second case study explores the mixture of local and Hadhrami influences in the Islamic practice of South Sumatra, while the third case study examines an imported form of reform Islam in a transmigrasi settlement. Of major importance in these case studies will be what influences the religious authority figures and what tools are used to disseminate their thoughts and interpretations of Islam. I argue that the concept of the religioscape enables us to better understand the impact that religious authority figures have on their surroundings and vice versa. It can also serve as a methodological tool to grasp the diverse plurality of Islamic practices in Indonesia.

Unique Failure Modes from use of Sn-Pb and Lead-Free (mixed metallurgies) in PCB Assembly: Case Study

2005 ◽  
Author(s):  
Frank Toth ◽  
Gary F. Shade
Keyword(s):  
Printed Circuit Board ◽  
Failure Modes ◽  
Circuit Board ◽  
Lead Free ◽  
Printed Circuit ◽  
Pcb Assembly ◽  
New Process ◽  
Solder Pastes

Abstract Printed Circuit Board (PCB) assemblies are moving toward lead-free (LF) alloys and away from the traditional Sn-Pb alloy [1]. This change is creating new and unique failure modes as the process adapts to accommodate the higher temperatures of the new process [2]. In addition, mis-processed lots are more likely due to the complexity of assembling a mix of Sn-Pb and leadfree solders, components, PCBs, solder pastes, and fluxes. This case study helps to highlight the challenge and provides an example of what can happen, how to detect it, and how the defects can cause reliability failures.

Underfill Design for Low-k Dielectrics and Lead Free Applications

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001465-001485
Author(s):  
Brian Schmaltz ◽  
Yukinari Abe ◽  
Kazuyuki Kohara
Keyword(s):  
Stress Concentration ◽  
Dielectric Layer ◽  
Failure Modes ◽  
High Stress ◽  
High Strength ◽  
Lead Free ◽  
Typical Result ◽  
High Stress Concentration ◽  
Technology Nodes ◽  
Low K

As technology nodes progress to 32/28nm and beyond underfill materials are presented with the significantly challenging task of maintaining bump protection while ensuring ultra low-K dielectric (ULK/ELK) integrity. This challenge is further complicated by the trend toward RoHS compliancy(lead-free) and a ever increasing die size. Through extensive research and testing, several specifically formulated underfill materials were determined acceptable solutions for these complex issues. As technology nodes progress to smaller process generations a high stress concentration is seen at the dielectric layer during thermal cycling. This stress is a typical result of a high glass transition temperature (Tg) / high strength material that often leads to a cracking failure mode of the thin dielectric layer. Too low of a Tg presents a high stress concentration on the bumps which once again constitutes failure, this time however the crack is typically seen at the bump location. This high stress concentration seen at the bumps is more significant when lead free bumps are considered due to their inherent fragile nature. Underfill materials must now be specifically formulated and optimized to solve these failure modes for a large variable of package types. This paper will discuss solutions to typical failure modes currently seen with reliability testing of present and future technologies.

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