Failure in Tungsten-Filled Via Structures

1995 ◽  
Vol 391 ◽  
Author(s):  
J. J. Clement ◽  
J. R. Lloyd ◽  
C. V. Thompson
Keyword(s):  
Thermal Expansion ◽  
Current Density ◽  
Void Growth ◽  
Test Results ◽  
Resistance Increase ◽  
Test Conditions ◽  
Structure Geometry ◽  
Service Conditions ◽  
Differential Thermal Expansion ◽  
Improve Reliability

AbstractFailure of the tungsten-filled via interconnect structure is modelled. Two mechanisms contributing to void growth are considered: relief of stress due to differential thermal expansion, and electromigration. A self-limiting void volume is predicted, resulting in a self-limiting resistance increase which is a function of structure geometry and the void morphology. The relative contributions of the two mechanisms change significantly as the temperature and current density are reduced from accelerated test conditions, affecting the extrapolation of test results to service conditions. Modified procedures for extrapolating lifetimes are discussed, as well as suggested process changes to improve reliability.

Interconnect Failure Mechanism Maps for Different Metallization Materials and Processes

1999 ◽  
Vol 563 ◽  
Author(s):  
V. K. Andleigh ◽  
Y. J. Park ◽  
C. V. Thompson
Keyword(s):  
Failure Mechanism ◽  
Current Density ◽  
Void Growth ◽  
Void Nucleation ◽  
Failure Mechanisms ◽  
Line Length ◽  
Test Results ◽  
Interconnect Reliability ◽  
Current Densities ◽  
Service Conditions

AbstractA tool for simulation of electromigration and electromigration-induced damage, MIT/EmSim, has been used to investigate interconnect reliability, focusing on transitions in failure mechanisms associated with void nucleation, growth, and growth saturation. Conventional scaling of electromigration test results assume that the median time to electromigration-induced failure scales with the current density j to the power −n. The effects of transitions in failure mechanisms have been studied by characterizing the apparent current density exponent. When failure is limited by void nucleation, n=2 scaling is observed, and when failure requires substantial void growth, n=1 scaling is observed. When lines end at diffusion barriers such as W or liner-filled vias, void growth saturates in short lines at low current densities, and, depending on the failure criterion, lines under these conditions can be ‘immortal’. As growth saturates, apparent current density exponents increase above 2. Failure mechanism maps can be constructed to illustrate the failure mechanisms and scaling behavior as a function of line length and current density. Failure maps can be used in accurately scaling test results to service conditions, to suggest layout strategies for optimized circuit reliability, and to assess the reliability of new interconnect materials and structures.

A Damage Integral Based Analysis and Simulation of the Thermal Fatigue of Diebonds

1993 ◽  
Vol 323 ◽  
Author(s):  
David A. Lilienfeld ◽  
Peter Børgesen ◽  
Che-Yu Li
Keyword(s):  
Computer Simulation ◽  
Thermal Expansion ◽  
Growth Parameters ◽  
Constitutive Relations ◽  
Epoxy Adhesive ◽  
Integral Approach ◽  
Test Results ◽  
Adhesive Layers ◽  
Damage And Failure ◽  
Service Conditions

AbstractMicroelectronic packages undergo substantial thermal excursions during processing and often in service. Differences in the thermal expansion of the various components may therefore lead to fatigue of the interconnects. A computer simulation has been developed which is based on a damage integral approach for the modeling of damage and failure in the various bonding layers found throughout such a package. This code should apply equally well to solder die bonds and polymeric or epoxy adhesive layers, assuming that the corresponding crack growth parameters and constitutive relations are known. Using literature values for these properties, predictions have been compared to experimental thermal cycling data for solder die bonds. Consequences for the extrapolation of accelerated test results to service conditions are discussed.

Answering the Questions of the Psychologist Assessing the Visually Handicapped Child

1975 ◽  
Vol 69 (8) ◽  
pp. 350-353
Author(s):  
John L. Morse
Keyword(s):  
Classroom Observation ◽  
Handicapped Child ◽  
Test Results ◽  
Visual Condition ◽  
Inappropriate Behaviors ◽  
Test Conditions ◽  
Visually Handicapped ◽  
First Time

The most common question asked by the psychologist who is faced for the first time with assessing a visually handicapped child are answered. The 15 questions include such areas as the required information concerning visual condition, background of the client, test conditions, the role of the parents, classroom observation, behaviors observed during testing, evaluation of test results, expectations of parents and teachers, and modification of a child's inappropriate behaviors.

scholarly journals Simulation of loop test conditions for the modified SM reactor fuel rods and test results in justification of their performance

2013 ◽  
Vol 2013 (2) ◽  
pp. 105-113
Author(s):  
Vladimir Aleksandrovich Starkov ◽  
Fedoseev V.E. Fedoseev ◽  
Shishin V.Yu. Shishin
Keyword(s):  
Reactor Fuel ◽  
Test Results ◽  
Fuel Rods ◽  
Test Conditions

Thermally Induced Synchronous Instability of a Radial Inflow Overhung Turbine: Part I

1997 ◽  
Author(s):  
H. B. Faulkner ◽  
W. F. Strong ◽  
R. G. Kirk
Keyword(s):  
Thermal Expansion ◽  
Operating Speed ◽  
Lateral Motion ◽  
Turbine Wheel ◽  
Thermally Induced ◽  
Lateral Dynamics ◽  
Morton Effect ◽  
Speed Range ◽  
Differential Thermal Expansion ◽  
Rotor Dynamic

Abstract This paper is in two parts, and concerns the lateral dynamics of a large turbocharger rotor with overhung wheels. Initial rotor dynamic analysis indicated no excessive motion in the operating speed range. However, testing showed excessive motion, which was initially traced to the radial-inflow turbine wheel becoming loose on the shaft, due to transient differential thermal expansion in the wheel on startup. The attachment of the wheel was modified to eliminate this problem. The discussion up to this point is in Part I of the paper, and the remainder is in Part II. The wheel attachment modification extended the range of satisfactory operation upward considerably, but excessive lateral motion was again encountered near the upper end of the operating speed range. This behavior was traced to thermal bowing of the shaft at the turbine end, known as the Morton Effect. The turbine end bearing was modified to eliminate this problem, and satisfactory operation was then achieved throughout the operating speed range.

scholarly journals Carbon Fibre - Copper Composites Obtained by Foil Casting

1994 ◽  
Vol 3 (2) ◽  
pp. 096369359400300
Author(s):  
W.K. Wtosiński ◽  
W. Olesińska ◽  
K. Pietrzak ◽  
D. Kaliński
Keyword(s):  
Thermal Expansion ◽  
Carbon Fibre ◽  
Casting Process ◽  
Fibre Content ◽  
Resistance Welding ◽  
Test Results ◽  
Micro Hardness ◽  
Electric Contacts

A method for production of carbon fibre - copper composites by foil casting is presented. As follows from the test results included, the foil casting process may be applied to produce the carbon fibre -copper composites. Thanks to the use continuous fibres, the method allows to obtain composites with fibres ordered directionally. Measurements of thermal expansion and micro-hardness of a composite with 30% fibre content, as well as examination of its microstructure are presented. The composites may, among others, find application in manufacturing of electrodes for resistance welding, electric contacts and expansion wafers for semiconductor power components.

Nanoscale Structural Characterization at the Titanium/Sol-Gel/Primer/PETI-5 Interface

1999 ◽  
Vol 5 (S2) ◽  
pp. 774-775
Author(s):  
James D. Holbery ◽  
Robert M. Fisher
Keyword(s):  
Environmental Exposure ◽  
High Speed ◽  
Sol Gel ◽  
Titanium Substrate ◽  
Interfacial Region ◽  
High Toughness ◽  
Test Conditions ◽  
Environmental Test ◽  
Environmentally Safe ◽  
Service Conditions

Characteristics of the interfacial region between a polymer and substrate are critical to the durability of adhesive-adherend system performance. The High Speed Civil Transport (HSCT) requires structural laminates to be light weight, non-corrosive, environmentally safe, and able to withstand extreme service conditions (Mach 2.4 with in-service temperatures at 177°C, projected life to 120,000 hours). The present work characterizes multi-layer laminates comprised of a Titanium substrate (6A1-4V and 15V-3Cr-3Al-3Sn alloy), a silicate/zirconate sol-gel coating with aminopropyl functionality (nominally 1000 Angstroms), a NASA developed PETI-5 psuedothermoplastic polyimide primer (nominally 1000 Angstroms), and a high toughness, thermo-oxide stable PETI-5 adhesive. Previous studies report the physical effect of aging; therefore, this work aims to measure the nano-mechanical properties of the interface utilizing nano-indentation and AFM, focusing on the accelerated time-dependent changes due to extreme environmental exposure.Samples were prepared by sectioning each laminate (No Environmental Exposure, 1000 and 2000 Hours at 200°C) in two locations, one section externally exposed to environmental test conditions and the other from the middle of the laminate.

scholarly journals Pullout Behavior of GFRP Anti-Floating Anchor Based on the FBG Sensor Technology

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ming-yi Zhang ◽  
Zheng Kuang ◽  
Xiao-yu Bai ◽  
Xiao-yu Chen
Keyword(s):  
Axial Force ◽  
Shear Failure ◽  
Distribution Functions ◽  
Sensor Technology ◽  
Force Distribution ◽  
Test Results ◽  
Glass Fiber Reinforcement ◽  
Promising Solution ◽  
Service Conditions ◽  
Fbg Sensors

Building anti-floating anchors have been increasingly used in recent years, but conventional steel anchors under service conditions are easily subjected to chemical erosion. Glass fiber reinforcement polymer (GFRP) is a promising solution to this problem. In this study, field pullout tests were conducted on three full instrumented GFRP anti-floating anchors in weathered granite. Specifically, the GFRP anchors during pultrusion were innovatively embedded with bare fiber Bragg grating (FBG) sensors to monitor the axial force distribution along depth. It was found that the embedded FBG could reliably monitor the axial force distribution of GFRP anchors. The ultimate pullout force of a GFRP anchor with diameter of 28 mm and anchorage length of 5 m was up to 400 kN. The GFRP anchor yielded at 0.8 m underground. Force distribution and field photos at failure indicated shear failure occurred at the anchor/bolt interface at the end of the tests. The feasibility of the GFRP anti-floating anchor was also verified in civil engineering. Finally, an elastic mechanical model and Mindlin’s displacement solution are used to get distribution functions of axial force and shear stress along the depth, and the results accord with the test results.

Numerical Seakeeping Simulation of Model Test Condition for Two-Ship Interaction in Waves

2007 ◽  
Author(s):  
Lin Li
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Current Paper ◽  
Free Motion ◽  
Test Results ◽  
Wave Excitation ◽  
Motion Constraints ◽  
Test Conditions ◽  
Motion Modes ◽  
Simulation Results

In order to validate the numerical prediction of two-ship interactions in waves, the model test calibration has to be conducted. However, motion constraints are usually applied when model tests are carried out for the measurement of wave excitation forces and moments in certain selected motion modes for both ships. Therefore, in current paper, a numerical seakeeping simulation of the model test conditions has been studied. Restraints in surge, sway and yaw, as well as the free motion modes in heave, roll and pitch have been all applied to both the ships, experimentally and numerically. The restraint forces and the unrestrained motions have been compared with the model test results and numerical simulation results. Fairly good agreements have been found.

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