Mechanical Stress Measurements in Damascene-Fabricated Aluminum Interconnect Lines

1999 ◽  
Vol 594 ◽  
Author(s):  
Paul R. Besser
Keyword(s):  
Shear Stress ◽  
Stress State ◽  
Aspect Ratio ◽  
Tensile Stress ◽  
Mechanical Stress ◽  
Hydrostatic Stress ◽  
Maximum Shear Stress ◽  
Compressive Stresses ◽  
Biaxial Tensile Stress ◽  
Interconnect Lines

AbstractThe mechanical stress state of damascene-fabricated Al interconnect lines was determined on an array of lines on the product die of a logic technology device. Narrow, unpassivated, damascene Al lines have a purely hydrostatic stress (108 MPa). The hydrostatic stress of damascene Al lines (411 MPa) is much larger once the dielectric is deposited. However, the maximum shear stress remains small in magnitude, compared to RIE Al lines of similar thermal history and aspect ratio. The stress of damascene lines was measured as a function of linewidth. Unpassivated, wide lines, have compressive stresses along the length and width and zero along the line height. Passivated wide lines have a biaxial, tensile stress in-plane and zero along the line height.

Determination of the Biaxial Anisotropy Coefficient Using a Single Layer Sheet Metal Compression Test

2021 ◽  
Vol 883 ◽  
pp. 303-308
Author(s):  
Peter Hetz ◽  
Matthias Lenzen ◽  
Martin Kraus ◽  
Marion Merklein
Keyword(s):  
Stress State ◽  
Tensile Stress ◽  
Sheet Metal ◽  
Compression Test ◽  
Test Procedure ◽  
Rolling Direction ◽  
Single Layer ◽  
Material Behavior ◽  
Biaxial Tensile ◽  
Biaxial Tensile Stress

Numerical process design leads to cost and time savings in sheet metal forming processes. Therefore, a modeling of the material behavior is required to map the flow properties of sheet metal. For the identification of current yield criteria, the yield strength and the hardening behavior as well as the Lankford coefficients are taken into account. By considering the anisotropy as a function of rolling direction and stress state, the prediction quality of anisotropic materials is improved by a more accurate modeling of the yield locus curve. According to the current state of the art, the layer compression test is used to determine the corresponding Lankford coefficient for the biaxial tensile stress state. However, the test setup and the test procedure is quite challenging compared to other tests for the material characterization. Due to this, the test is only of limited suitability if only the Lankford coefficient has to be determined. In this contribution, a simplified test is presented. It is a reduction of the layer compression test to one single sheet layer. So the Lankford coefficient for the biaxial tensile stress state can be analyzed with a significantly lower test effort. The results prove the applicability of the proposed test for an easy and time efficient characterization of the biaxial Lankford coefficient.

Analysis of Performance Decay Behavior for Asphalt Pavement Based on Aging

2013 ◽  
Vol 723 ◽  
pp. 22-26 ◽  
Author(s):  
Pei Long Li ◽  
Zhan Ding ◽  
Zheng Qi Zhang
Keyword(s):  
Shear Stress ◽  
Service Life ◽  
Tensile Stress ◽  
Simulation Analysis ◽  
Asphalt Pavement ◽  
Maximum Shear Stress ◽  
Maximum Tensile Stress ◽  
Pavement Structure ◽  
Analysis Of Performance ◽  
Decay Behavior

Aging is a main factor affecting the durability of asphalt pavement. To study decay behavior of asphalt pavement with aging, aged asphalt was extracted from stratified pavement mixtures for different service-life. The changes of asphalt properties with service time and depth variations of the pavement were discussed. And numerical simulation analysis of pavement structure was conducted with pavement gradient modulus changes caused by aging. The results indicate that asphalt stiffness increases and low-temperature performance decays sharply with the extension of pavement service life, especially in the first several years. The vertical aging differences from top to bottom of pavement were significant, the aging extents decrease continuously from the surface, which cause the gradient changes of pavement modulus. The maximum tensile stress and maximum shear stress all increase with surface modulus increasing, so more serious aging can induce greater gradient modulus, shear stress and tensile stress are larger under the same loads, which have more serious damage to the pavement structure.

Discussions on Fracture Factors of Brittle Materials under the Shear-Compression Condition

2011 ◽  
Vol 250-253 ◽  
pp. 90-94
Author(s):  
Zhi Hui Li ◽  
Jun Ping Shi ◽  
An Min Tang
Keyword(s):  
Shear Stress ◽  
Stress State ◽  
Uniaxial Compression ◽  
Frictional Force ◽  
Shear Fracture ◽  
Maximum Shear Stress ◽  
Brittle Materials ◽  
Fracture Mechanisms ◽  
Initiation Point ◽  
Fracture Angle

Based on fundamental ideas in tribology and basic concept of stress state in solid mechanics, the existence of frictional force on shear plane is discussed under uniaxial compression of brittle materials. On account of macroscopic fracture forms and mesoscopic fracture mechanisms, the key factors influencing shear fracture angle are analyzed. The results show that, when brittle materials are compressed and shear fracture occurs, shear fracture surface at the crack initiation point is consistent with the maximum shear stress. But the reason of shear fracture angle examined in experiment greater than 45º lies in that, the existence of frictional force between endface of specimen and pressure head of testing machine, and additional tensile stress produced in the materials when harder crystalline grain wedge in softer medium have changed original uniaxial compression stress state and the direction of maximum shear stress on next fracture path.

The Force Impact Analysis of Steel Bridge Deck Pavement Layer Modulus and Pavement Thickness to Pavement System

2011 ◽  
Vol 368-373 ◽  
pp. 289-292
Author(s):  
San Qiang Yang ◽  
Pei Wen Hao ◽  
Li Qun Tang ◽  
Tao Liu
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Tensile Stress ◽  
Bridge Deck ◽  
Maximum Shear Stress ◽  
Maximum Tensile Stress ◽  
Steel Bridge ◽  
Epoxy Asphalt ◽  
Pavement Thickness ◽  
Bridge Deck Pavement

This epoxy asphalt used by the U.S., Japan Epoxy Asphalt two steel bridge deck pavement materials at different thickness analysis of pavement deformation force. Pavement derived the maximum tensile stress, shear stress and elastic modulus, pavement thickness of mathematical models. The results showed that: Pavement maximum tensile stress, shear stress, pavement elastic modulus with available four times a polynomial equation fitted, pavement surface transverse maximum stress increases as the pavement thickness decreases, horizontal maximum shear stress between layers does not increase with the pavement thickness decreases, but the thickness of the pavement at 40-50mm have a peak, then gradually increases with the thickness decreases.

Effect of Interlayer on the Elastic-Plastic Deformation of Coating Systems

2019 ◽  
Vol 35 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Y. X. Guo ◽  
Y. W. Zhao
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Tensile Stress ◽  
Maximum Shear Stress ◽  
Indentation Load ◽  
Interlayer Thickness ◽  
The Finite Element Method ◽  
Thickness Increase ◽  
Elastic Plastic

ABSTRACTThe finite element method (FEM) was used to study the elastic-plastic contact in the coating systems with interlayer. The results reveal that with the increase of interlayer thickness, the maximum shear stress of coating/interlayer and interlayer/substrate interfaces decreases. Moreover, the sharply changed shear stress between the interfaces of coating/interlayer and interlayer/substrate decreases too. There is no further decrease when interlayer thickness increase to 0.04 mm and above. With the increasing of interlayer elastic modulus, the shear stress of coating/interlayer interface decreases while the shear stress of interlayer/substrate interface increases. Meanwhile, the higher elastic modulus leads to the intensive tensile stress concentration on the interface of coating/interlayer. Hence, the interlayer with appropriate elastic modulus not only reduces the shear stress of coating/interlayer and interlayer/substrate interfaces but also decreases the tensile stress of coating/interlayer interface. The mechanical properties of coating systems were investigated with different interlayer yield strength. The effective hardness and elastic modulus increase with the increase of interlayer yield strength, which is good to protect the substrate from the deformation. In addition, higher indentation load can lead to the decrease of effective hardness and elastic modulus.

scholarly journals Effects of Aspect Ratio and Plate Thickness on the Behavior of Unstiffened Steel-Plate Shear Walls with Pinned and Rigid Connections

2018 ◽  
Vol 4 (6) ◽  
pp. 1383 ◽  
Author(s):  
Rahim Abdi ◽  
Nader Abdoli Yazdi
Keyword(s):  
Shear Stress ◽  
Aspect Ratio ◽  
Steel Plate ◽  
Maximum Shear Stress ◽  
Plate Thickness ◽  
Shear Walls ◽  
Steel Plate Shear Walls ◽  
Lateral Resistance ◽  
Buckling Behavior ◽  
Rigid Connection

Unstiffened steel plate shear walls (SPSWs) have been in use mostly in recent years. In this numerical study, the buckling behavior of a single-storey single-bay unstiffened SPSW with two pinned and rigid beam-column connections under lateral loading is investigated. The SPSW had different wall aspect ratios (L/h=1, 1.5, 2, 2.5, and 3) and infill plate thicknesses (tw= 3, 5, and 7 mm). Their effect on the buckling behavior of SPSW was examined using buckling analysis in ABAQUS software. Results indicated that with the increase of infill plate thickness, the lateral resistance of unstiffened SPSW system increases, but by increasing wall aspect ratio, its resistance decreases. In both connection designs, the model with L/h=1 (square-shaped model) showed better ductility and higher stiffness and strength in all three thicknesses. Maximum shear stress responses of SPSW models showed that in pinned design with L/h=1, the most change in shear stress values was 8% when infill plate thickness reached from 5 to 7 mm; while for rigid connection, it was reported as 7% when it increased from 3 to 5 mm. This indicates that in rigid connection, increasing the infill plate thickness has less effect on the increase of lateral resistance. By examining the performance of rigid and pinned beam-to-column connections with different wall aspect ratio and infill plate thickness, it was found out that maximum shear stress in rigid connection increased by 11% compared to pin connection. It was concluded that an optimum unstiffened SPSW model had a wall aspect ratio of 1 and infill plate thickness of 7 mm.

The Initiation and Propagation of Fatigue Cracks in Mild Steel Pieces of Square Section

1954 ◽  
Vol 4 (1) ◽  
pp. 1-18 ◽  
Author(s):  
H. L. Cox ◽  
J. E. Field
Keyword(s):  
Shear Stress ◽  
Tensile Stress ◽  
Mild Steel ◽  
Fatigue Cracks ◽  
Maximum Shear Stress ◽  
Shear Stresses ◽  
High Shear ◽  
Stress Range ◽  
High Shear Stress ◽  
General Direction

SummaryAn investigation has been made to determine the positions and directions of initiation and the directions of propagation of fatigue cracks and to examine the correlation between these positions and directions and the planes on which maximum tensile and maximum shear stresses are generated.To afford as wide a range as possible of the ratio of maximum shear stress to maximum tensile stress, tests have been made under combinations of alternating bending and torsion; and in order to separate partially the regions of high shear stress from those of high direct stress, the tests have been made on pieces of square section with the plane of bending parallel to one diagonal of the section. Two series of tests have been made; one a preliminary series on pieces having no parallel portion and the other on pieces having a parallel portion about three times the length of the side of the square section. The positions and directions of initiation and the directions of propagation of fatigue cracks have been observed and compared with the positions and directions of the maximum tensile and shear stresses.Fatigue cracks may be initiated as a result of either high shear stress or high tensile stress and in the present series of tests on mild steel, cracking in tension has occurred in preference to cracking in shear when the ratio of the tensile stress range to the shear stress range has exceeded about 1.6; for values of this ratio less than 1.6, the cracks started in shear (and vice versa); propagation along the plane of maximum shear appears to be preferred up to a slightly greater value of the tensile/shear ratio (about 1.7 possibly). The general direction of a crack formed as a result of high tension usually follows the plane of maximum tension and that of a crack formed as a result of shear usually follows the plane of maximum shear. In detail both types of crack—in this mild steel—deviate quite widely from their general directions but this deviation bears no obvious relation to the microstructure of the material. Cracks propagating along one plane of maximum shear occasionally show a marked tendency to branch along the associated plane of maximum shear; but this tendency is not always observed and in other cases no tendency to branch has been noted.

Sign in / Sign up

Export Citation Format

Share Document