Limiting mechanisms of slow dilatant plastic shear deformation of granular media

Nature ◽  
1988 ◽  
Vol 336 (6194) ◽  
pp. 52-54 ◽  
Author(s):  
T. Dunstan ◽  
J. R. F. Arthur ◽  
A. Dalili ◽  
O. O. Ogunbekun ◽  
R. K. S. Wong
Keyword(s):  
Shear Deformation ◽  
Granular Media ◽  
Plastic Shear

Thermal- And Electromigration- Induced Stresses In Passivated Al- And Alsicu-Interconnects

1996 ◽  
Vol 428 ◽  
Author(s):  
D. Beckers ◽  
H. Schroeder ◽  
I. Eppler ◽  
W. Schilling
Keyword(s):  
Thermal Cycling ◽  
Shear Deformation ◽  
Electronic Devices ◽  
Electrical Current ◽  
Al Alloys ◽  
Plastic Shear ◽  
Stress Evolution ◽  
Experimental Parameters ◽  
Induced Stresses ◽  
Electrical Current Density

AbstractAl and Al- alloys are commonly used as interconnect materials in integrated electronic devices. Stress induced voiding and degradation of metal lines by electromigration are closely related to the stresses in the lines.We have studied the strain and stress evolution during thermal cycling, isothermal relaxation and due to electromigration in passivated Al and AlSi(1%)Cu(0.5%) lines by Xray diffraction with variation of experimental parameters such as the aspect ratio and the electrical current density. Furthermore the extent of voiding and plastic shear deformation has been determined from the experimental metal strains with the help of finite element calculations.Main results are: 1) During thermal cycling the voiding is less than 2.10-3. The extent of plastic shear deformation increases with increasing line width and with decreasing flowstress. 2) During isothermal relaxation void growth occurs but no significant change in the plastic shear deformation. 3) An electric current in the lines causes no measurable additional change of the volume averaged stresses up to line failure.

Analysis of Stresses and Strains In Passivated Metal Lines

1996 ◽  
Vol 436 ◽  
Author(s):  
I. Eppler ◽  
H. Schroeder ◽  
U. Burges ◽  
W. Schilling
Keyword(s):  
Integrated Circuits ◽  
Shear Deformation ◽  
Plastic Shear ◽  
Thermally Induced ◽  
Flat Substrate ◽  
Thermal Expansion Coefficients ◽  
Aspect Ratios ◽  
Induced Stresses ◽  
Proper Values ◽  
Passivated Metal

AbstractPassivated metal lines, commonly used in integrated circuits, show thermally induced stresses due to the difference of the thermal expansion coefficients of the lines and their surroundings. These stresses cause voidage and plastic flow of the lines. Aim of the analysis was to derive equations connecting experimentally measured strains or stresses by the X-ray diffraction and wafer curvature techniques with the magnitude of voidage and plastic shear deformation of the lines.Using the concepts of linear elasticity the volume averaged stresses of an array of parallel interconnects embedded in a passivation layer on a flat substrate are analysed. Equations are derived connecting the volume averaged stresses in the metal and in the passivation with the “Heigen-strains” of the metal which characterize the true (stress free) thermal strains and plastic deformation strains of the metal. The coefficients entering these equations are determined from (elastic) finite element method (FEM) calculations performed for various geometries and aspect ratios of the metal lines. Choosing the proper values of the coefficients allows the eigen- strains to be determined from the experimental data.By comparison of the evaluated eigen-strains with the purely elastic eigen-strains ΔαΔT the extent of voidage and/or plastic shear deformation of passivated metal lines caused by thermally induced stresses can be determined model independently.

Atomic-level structural modifications induced by severe plastic shear deformation in bulk metallic glasses

2011 ◽  
Vol 64 (1) ◽  
pp. 81-84 ◽  
Author(s):  
X.D. Wang ◽  
Q.P. Cao ◽  
J.Z. Jiang ◽  
H. Franz ◽  
J. Schroers ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Atomic Level ◽  
Plastic Shear ◽  
Structural Modifications
Sign in / Sign up

Export Citation Format

Share Document