Mechanisms of Inelastic Deformation and Stress Relaxation in Thin Metallizations Bonded to Hard Substrates

1991 ◽  
Vol 225 ◽  
Author(s):  
M. A. Korhonen ◽  
P. Brørgesen ◽  
Che-Yu Li
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Integrated Circuits ◽  
Large Scale ◽  
Effective Means ◽  
Grain Boundary Sliding ◽  
Dislocation Creep ◽  
Dislocation Glide ◽  
Constrained Deformation ◽  
Hard Substrates

ABSTRACTThe yield strength of metallic thin films bonded to hard substrates can be significantly higher than is customary for bulk samples of the same metal. This is related to the constrained nature of the deformation. The constrained deformation, as well as the commonly observed crystallographic texture of thin films, places restrictive conditions on the mechanisms of deformation that produce stress relaxation. In narrow aluminum based metallizations used as interconnects in large scale integrated circuits thermal stress induced voiding provides an effective means for stress relaxation. For these interconnects, the stress state is tensile after excursions to higher temperatures; the stresses relax mainly by dislocation glide and grain boundary sliding during the cooldown, while the longer term relaxation is governed by stress-induced voiding and dislocation creep.

Mechanisms of Inelastic Deformation and Stress Relaxation in Thin Metallizations Bonded to Hard Substrates

1991 ◽  
Vol 226 ◽  
Author(s):  
M.A. Korhonen ◽  
P. Bergesen ◽  
Che-Yu Li
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Integrated Circuits ◽  
Large Scale ◽  
Effective Means ◽  
Grain Boundary Sliding ◽  
Dislocation Creep ◽  
Dislocation Glide ◽  
Constrained Deformation ◽  
Hard Substrates

AbstractThe yield strength of metallic thin films bonded to hard substrates can be significantly higher than is customary for bulk samples of the same metal. This is related to the constrained nature of the deformation. The constrained deformation, as well as the commonly observed crystallographic texture of thin films, places restrictive conditions on the mechanisms of deformation that produce stress relaxation. In narrow aluminum based metallizations used as interconnects in large scale integrated circuits thermal stress induced voiding provides an effective means for stress relaxation. For these interconnects, the stress state is tensile after excursions to higher temperatures; the stresses relax mainly by dislocation glide and grain boundary sliding during the cooldown, while the longer term relaxation is governed by stress-induced voiding and dislocation creep.

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.

scholarly journals Grain Growth and Mechanical Behaviour of Polar Ice

1985 ◽  
Vol 6 ◽  
pp. 79-82 ◽  
Author(s):  
P. Duval
Keyword(s):  
Crystal Growth ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Migration ◽  
Grain Boundary Sliding ◽  
Dislocation Creep ◽  
Polar Ice ◽  
Dislocation Glide ◽  
Ice Caps ◽  
Polar Snow

Crystal size in polar ice caps increases with depth from the snow surface down to several hundred meters. Data on crystal growth in isothermal polar snow and ice show the same linear relationship between the size of crystals and their age. This paper reviews the mechanical behavior of polar ice which exhibits grain growth. Grain boundary migration associated with grain growth appears to be an efficient accomodation process for grain boundary sliding and dislocation glide. For grain growth to occur, strain energy must always be lower than the free energy of boundaries. The sintering of ice particles in polar firn is energized by the pressure due to the overburden of snow. Dislocation creep must be taken into account to explain the densification rate in the intermediate and final stage Constants of power law creep should depend on the crystal growth rate.

Mechanism for Subambient Interfacial Pressures While Polishing With Liquids

1999 ◽  
Vol 122 (2) ◽  
pp. 450-457 ◽  
Author(s):  
Joseph A. Levert ◽  
Steven Danyluk ◽  
John Tichy
Keyword(s):  
Integrated Circuits ◽  
Contact Stress ◽  
Relative Velocity ◽  
Large Scale ◽  
Single Crystal Silicon ◽  
Leading Edge ◽  
Liquid Viscosity ◽  
Crystal Silicon ◽  
Lower Contact ◽  
Hard Substrates

This paper reports the results of a model for predicting the development of subambient pressures during the polishing of flat hard substrates by sliding against a compliant pad in the presence of a slurry (liquid). This work is an extension of our prior experimental work on the polishing of single crystal silicon wafers with polyurethane pads and high pH slurries containing silica particles. Subambient pressures have important implications in the polishing rate and uniformity of silicon and, therefore, in the manufacture of large-scale integrated circuits. The subambient pressure is the result of pad asperity compression at the wafer leading edge followed by elastic reexpansion beneath the wafer due to the nonuniform wafer/pad contact stress. Liquid is expelled from interasperity voids where high leading edge contact stress causes asperities to be compressed. Lower contact stress behind the leading edge causes asperity reexpansion leading to recreation of interasperity voids and subambient liquid pressures. A Poiseuille like in-flow of liquid from the sides of the wafer limits the value of the subambient pressure. Numerical simulations predict subambient pressures as a function of liquid viscosity and relative velocity of the pad and wafer and the pad and wafer mechanics which follow the same trend as the experimental data. [S0742-4787(00)01702-1]

Stress Relaxation in Al-Si-Cu Thin Films and Lines

1994 ◽  
Vol 356 ◽  
Author(s):  
A. Witvrouw ◽  
J. Proost ◽  
B. Deweerdt ◽  
Ph. Roussel ◽  
K. Maex
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Flow Stress ◽  
Stress Relaxation ◽  
Relaxation Data ◽  
Cu Films ◽  
Dislocation Glide ◽  
Average Activation Energy ◽  
Curvature Measurements ◽  
Substrate Curvature

AbstractSubstrate curvature measurements were used to study stress relaxation in Al-Si-Cu films at temperatures between 45 and 165 °C. Dislocation glide with an average activation energy, resp. athermal flow stress of 1.7 ± 0.2 eV, resp. 600 ± 200 MPa could describe the relaxation data for temperatures up to 120 °C well. Stress relaxation at 92 °C was found to progress much slower in 1 μm wide nitride passivated lines than in thin films or unpassivated lines.

Plasma Assisted Chemical Vapor Deposition of Aluminum For Metallization In Ulsi

1996 ◽  
Vol 427 ◽  
Author(s):  
Dong-Chan Kim ◽  
Young-Soung Kim ◽  
Seung-Ki Joo
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Integrated Circuits ◽  
Vapor Deposition ◽  
Large Scale ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Thermal Cvd ◽  
Dimethylethylamine Alane

AbstractAn aluminum thin film for ultra large scale integrated circuits(ULSI) metalization has been formed by PACVD using DMEAA(Dimethylethylamine alane) as a precursor. The selectivity was lost but the conformal step coverage was still maintained when the hydrogen plasma was added to conventional CVD process so that perfectly planarized metalization could be obtained.Comparing to thermal CVD, the reflectivity as well as the resistivity could be much improved especially when the film was deposited on SiO2. The deposition rate and the resistivity of PACVD Al thin films deposited on various substrates such as Si, TiN and SiO2 were compared with those of thermal CVD Al thin films.

Study of Pore Architecture in Silicon Oxide Thin Films by Variable-energy Positron Annihilation Spectroscopy

2002 ◽  
Vol 751 ◽  
Author(s):  
Kenji Ito ◽  
Yoshinori Kobayashi ◽  
Runsheng Yu ◽  
Kouichi Hirata ◽  
Hisashi Togashi ◽  
...  
Keyword(s):  
Thin Films ◽  
Porous Silicon ◽  
Integrated Circuits ◽  
Positron Annihilation ◽  
Large Scale ◽  
Silicon Oxide ◽  
Positron Annihilation Spectroscopy ◽  
Oxide Thin Films ◽  
Intensive Investigation ◽  
Variable Energy

ABSTRACTApplication of porous silicon oxide thin films to nanotechnology is under intensive investigation. Introducing a large amount of nano pores into a silicon oxide matrix is important to develop low-k dielectrics for future ultra-large-scale integrated circuits (ULSI). In this work, we applied variable-energy positron annihilation to the characterization of porous silicon oxide thin films fabricated on silicon wafers by sputtering and spincoating. It was found that the sputtered film has higher open pore connectivity than that of the spincoated low-k film.

Simulation of Microstructure and Surface Profiles of Thin Films for VLSI Metallization

MRS Bulletin ◽  
1995 ◽  
Vol 20 (11) ◽  
pp. 65-69 ◽  
Author(s):  
T. Smy ◽  
S.K. Dew ◽  
M.J. Brett
Keyword(s):  
Thin Films ◽  
Integrated Circuits ◽  
Metal Film ◽  
Large Scale ◽  
Local Heating ◽  
Surface Profile ◽  
Film Surface ◽  
Chemical Vapor ◽  
Current Crowding ◽  
Low Resistance

A crucial step in the manufacture of very large-scale integration (VLSI) integrated circuits is the fabrication of reliable, low-resistance metal interconnects between semiconductor devices. The fabrication of these interconnects is generally performed by depositing a blanket metal film and then patterning it by lithographic and etching techniques. The primary means of depositing thin metal films for VLSI interconnects are sputtering and chemical vapor deposition (CVD).The creation of reliable interconnects is, however, complicated by a number of issues. In order to obtain low contact resistance, to inhibit reactions with the silicon, and to provide good adhesion to both Si and SiO2, contact, barrier, and adhesion layers are generally deposited prior to the deposition of the low-resistance metal film that forms the bulk of the interconnect. If these layers are to provide an effective barrier to diffusion of the interconnection metal to the silicon, they must be deposited in a uniform, homogeneous form. It is also necessary that the primary interconnect material have as high step coverage as is possible in order to reduce current crowding, local heating effects, and electromigration. Unfortunately, as VLSI circuit densities have increased, the fabrication of interconnects requires high aspect-ratio contact cuts, and relatively severe local topographies can result. These factors make it difficult to deposit films with good step and bottom coverage.In addition to these concerns with the film surface profile, another factor is becoming increasingly significant. Both sputtering and CVD produce thin films with characteristic microstructures. This microstructure consists of columns or grains separated by grain boundaries and voids.

scholarly journals Grain Growth and Mechanical Behaviour of Polar Ice

1985 ◽  
Vol 6 ◽  
pp. 79-82 ◽  
Author(s):  
P. Duval
Keyword(s):  
Crystal Growth ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Migration ◽  
Grain Boundary Sliding ◽  
Dislocation Creep ◽  
Polar Ice ◽  
Dislocation Glide ◽  
Ice Caps ◽  
Polar Snow

Crystal size in polar ice caps increases with depth from the snow surface down to several hundred meters. Data on crystal growth in isothermal polar snow and ice show the same linear relationship between the size of crystals and their age. This paper reviews the mechanical behavior of polar ice which exhibits grain growth. Grain boundary migration associated with grain growth appears to be an efficient accomodation process for grain boundary sliding and dislocation glide. For grain growth to occur, strain energy must always be lower than the free energy of boundaries. The sintering of ice particles in polar firn is energized by the pressure due to the overburden of snow. Dislocation creep must be taken into account to explain the densification rate in the intermediate and final stage Constants of power law creep should depend on the crystal growth rate.

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