Stress relaxation and void formation in passivated Al(Cu) line structures

1998 ◽  
Author(s):  
I.-S. Yeo ◽  
P. S. Ho ◽  
S. G. H. Anderson ◽  
H. Kawasaki
Keyword(s):  
Stress Relaxation ◽  
Void Formation

The Influence of Tiw Barrier Layer on Reliability of AlCu and AlSiCu Interconnects

1995 ◽  
Vol 391 ◽  
Author(s):  
S. Kordic ◽  
R.A.M. Wolters ◽  
R.A. Augur ◽  
A.G. Dirks
Keyword(s):  
Stress Relaxation ◽  
Grain Boundaries ◽  
Barrier Layer ◽  
Void Formation ◽  
Diffusion Paths ◽  
Si Content

AbstractThe influence of a TiW barrier layer on the stress-voiding behavior of AlCu and AlSiCu interconnects is investigated. The results are compared to the same alloys deposited on SiO2- In both cases, AlCu exhibits a notably better voiding behavior compared to AlSiCu. In the case in which the alloys are directly deposited on the TiW barrier without breaking vacuum between TiW and Al(Si)Cu depositions, a significant improvement of the voiding behavior of both alloys is observed. Compared to AlCu, AlSiCu shows worse voiding behavior due to the presence of Si precipitates, which introduce significant extra dislocations and defects in the Al grains. These dislocations and defects are diffusion paths which assist stress relaxation and void formation. In the presence of a TiW barrier part of the Si content of the AlSiCu is consumed during the anneal by the Al-TiW interface, which results in a decreased number of dislocations and defects within the Al grains, and an improved voiding behavior compared to AlSiCu on SiO2-Furthermore, W and Ti diffuse into the grain boundaries of both alloys. The presence of W and Ti in the grain boundaries reduces the amount of Cu depletion from within the grains, which makes both alloys more resistant to stress voiding. The above is supported by Auger and TEM results. The electromigration results of the alloys in question are presented. These show that also with respect to electromigration AlCu is the preferred alloy both on TiW and SiO2.

Line width Dependence of Stress Relaxation and Yield Behavior of Passivated Al(Cu) Lines

1994 ◽  
Vol 338 ◽  
Author(s):  
I.-S. Yeo ◽  
S.G.H. Anderson ◽  
C.-N. Liao ◽  
D. Jawarani ◽  
H. Kawasaki ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Void Formation ◽  
Relaxation Behavior ◽  
Effect Of Temperature ◽  
Thermally Induced ◽  
Stress Relaxation Behavior ◽  
Cu Films ◽  
Dislocation Glide ◽  
Thermally Activated ◽  
On Line

ABSTRACTStress relaxation behavior of thermally induced stresses in passivated line structures is strongly influenced by the metal yield strength. For some line geometries, stress relaxation can lead to void formation. In this study, bending beam measurements have been carried out to measure the thermal stress and stress relaxation behavior of passivated Al(l wt.% Cu) line structures with 3, 1, and 0.5 µm line widths. Our results reveal that stress relaxation in Al(Cu) films and lines shows log(time) kinetics consistent with a thermally activated dislocation glide mechanism. The kinetics of stress relaxation depend on line geometry and temperature, which can be explained by a combined effect of temperature (mass transport) and shear stress (driving force).

Thermal Stresses in Passivated AlSiCu-Lines From Wafer Curvature Measurement

1994 ◽  
Vol 356 ◽  
Author(s):  
U. Burges ◽  
H. Helneder ◽  
M. Schneegans ◽  
D. Beckers ◽  
M. Hallerbach ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Thermal Cycling ◽  
Thermal Stresses ◽  
Void Formation ◽  
Evaluation Procedure ◽  
List Type ◽  
Type Number ◽  
X Ray ◽  
Wafer Curvature ◽  
Curvature Measurement

AbstractA wafer curvature technique was used to measure the mechanical stresses during thermal cycling and the isothermal stress relaxation in passivated Ti/TiN/AlSi(l%)Cu(0.5%)-lines (aspect ratio: 0.92) in the in-plane directions, parallel and perpendicular to the lines. The evaluation of the measured curvature data is explained in detail. The evaluation procedure was tested with the help of passivated SiO2-lines in which the stresses can be calculated because both, the SiO2-lines and the passivation, behave elastically. Comparision to elastic Finite-Element-Method calculations show excellent agreement. The main results are: a)During thermal cycling all stresses in the AlSiCu-lines vary linearly with temperature without significant hysteresis. The stress parallel to the lines is higher than perpendicular to the lines. X-ray stress data from the same sample confirm the wafer curvature data and show, additionally, that the stresses in the two directions perpendicular to the lines are equal.b)The isothermal stress relaxation depends strongly on the temperature with a maximum at 250°C. Void formation and growth probably control the observed relaxation.

Stress Relaxation and the Formation of Silicides in the Process of the Crystallization of NI-NB Films on SI

1991 ◽  
Vol 49 ◽  
pp. 898-899
Author(s):  
N. Rozhanski ◽  
V. Lifshitz
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Integrated Circuits ◽  
Direct Evidence ◽  
Alloy Film ◽  
Diffusion Barriers ◽  
Effective Barrier

Thin films of amorphous Ni-Nb alloys are of interest since they can be used as diffusion barriers for integrated circuits on Si. A native SiO2 layer is an effective barrier for Ni diffusion but it deformation during the crystallization of the alloy film lead to the appearence of diffusion fluxes through it and the following formation of silicides. This study concerns the direct evidence of the action of stresses in the process of the crystallization of Ni-Nb films on Si and the structure of forming NiSi2 islands.

BDNF Val⁶⁶Met polymorphism to generalized anxiety disorder pathways: Indirect effects via attenuated parasympathetic stress-relaxation reactivity.

2020 ◽  
Vol 129 (3) ◽  
pp. 237-247 ◽  
Author(s):  
Hsin-An Chang ◽  
Wen-Hui Fang ◽  
Yia-Ping Liu ◽  
Nian-Sheng Tzeng ◽  
Jia-Fwu Shyu ◽  
...  
Keyword(s):  
Anxiety Disorder ◽  
Stress Relaxation ◽  
Generalized Anxiety Disorder ◽  
Indirect Effects ◽  
Generalized Anxiety

STRESS RELAXATION IN SOLIDS

1987 ◽  
Vol 48 (C8) ◽  
pp. C8-3-C8-13 ◽  
Author(s):  
J. KUBÁT ◽  
M. RIGDAHL
Keyword(s):  
Stress Relaxation

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

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