scholarly journals MODELLING OF VOID NUCLEATION AND APPLICATION TO THE SIMULATION OF SPALL EXPERIMENTS

2019 ◽  
Author(s):  
FENG-GUO ZHANG
Keyword(s):  
Void Nucleation

In situ observations of electromigration induced void behavior

1995 ◽  
Vol 53 ◽  
pp. 244-245
Author(s):  
T. Marieb ◽  
J. C. Bravman ◽  
P. Flinn ◽  
D. Gardner ◽  
M. Madden
Keyword(s):  
Electron Microscopy ◽  
Void Nucleation ◽  
Plan View ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Microelectronics Industry ◽  
In Situ Observations ◽  
Backscatter Electron Detector ◽  
Voltage Scanning

Electromigration and stress voiding have been active areas of research in the microelectronics industry for many years. While accelerated testing of these phenomena has been performed for the last 25 years[1-2], only recently has the introduction of high voltage scanning electron microscopy (HVSEM) made possible in situ testing of realistic, passivated, full thickness samples at high resolution.With a combination of in situ HVSEM and post-testing transmission electron microscopy (TEM) , electromigration void nucleation sites in both normal polycrystalline and near-bamboo pure Al were investigated. The effect of the microstructure of the lines on the void motion was also studied.The HVSEM used was a slightly modified JEOL 1200 EX II scanning TEM with a backscatter electron detector placed above the sample[3]. To observe electromigration in situ the sample was heated and the line had current supplied to it to accelerate the voiding process. After testing lines were prepared for TEM by employing the plan-view wedge technique [6].

scholarly journals The Modified Void Nucleation and Growth Model (MNAG) for Damage Evolution in BCC Ta

2021 ◽  
Vol 11 (8) ◽  
pp. 3378
Author(s):  
Jie Chen ◽  
Darby J. Luscher ◽  
Saryu J. Fensin
Keyword(s):  
Growth Model ◽  
Damage Evolution ◽  
Volume Fraction ◽  
Void Nucleation ◽  
Nucleation And Growth ◽  
Void Coalescence ◽  
Hydrodynamic Simulations ◽  
Void Evolution ◽  
Void Nucleation And Growth ◽  
Nucleation Growth

A void coalescence term was proposed as an addition to the original void nucleation and growth (NAG) model to accurately describe void evolution under dynamic loading. The new model, termed as modified void nucleation and growth model (MNAG model), incorporated analytic equations to explicitly account for the evolution of the void number density and the void volume fraction (damage) during void nucleation, growth, as well as the coalescence stage. The parameters in the MNAG model were fitted to molecular dynamics (MD) shock data for single-crystal and nanocrystalline Ta, and the corresponding nucleation, growth, and coalescence rates were extracted. The results suggested that void nucleation, growth, and coalescence rates were dependent on the orientation as well as grain size. Compared to other models, such as NAG, Cocks–Ashby, Tepla, and Tonks, which were only able to reproduce early or later stage damage evolution, the MNAG model was able to reproduce all stages associated with nucleation, growth, and coalescence. The MNAG model could provide the basis for hydrodynamic simulations to improve the fidelity of the damage nucleation and evolution in 3-D microstructures.

Experimental Studies of the Reliability of Interconnect Trees

2000 ◽  
Vol 612 ◽  
Author(s):  
S.P. Hau-Riege ◽  
C.V. Thompson
Keyword(s):  
Integrated Circuits ◽  
Computer Aided Design ◽  
Void Nucleation ◽  
Experimental Studies ◽  
Single Layer ◽  
Electrical Current ◽  
Tree Structures ◽  
Current Configuration ◽  
Line Passing ◽  
Reliability Assessments

AbstractThe electromigration resistance of simple straight-line interconnects is usually used to estimate the reliability of complex integrated circuits. This is generally inaccurate, and overly conservative at best. The shapes and connectedness of interconnects is not accounted for in standard reliability assessments. We have identified the interconnect tree as the fundamental reliability unit. An interconnect tree consists of connected conducting line segments lying within a single layer of metallization, and terminating at two or more nodes at which there is a diffusion barrier such as a W-filled via. We performed electromigration experiments on the simplest tree structures, such as ‘L’- and ‘T’-shaped interconnects, as well as straight lines with an additional via in the middle of the line, passing currents of different magnitudes and directions through the limbs of the trees. We found that metal limbs ending in other limbs can act as reservoirs for electromigrating metal atoms. Passive reservoirs, which are limbs that do not carry electrical current, are generally beneficial for reliability, whereas limbs that do carry electrical current, called active reservoirs, can be beneficial or detrimental, depending on the direction and magnitude of the current in the reservoir. However, our experiments show that bends in interconnects do not affect their reliability significantly. We also found that the reliability of an interconnect tree can be conservatively estimated by considering void-growth and void-nucleation-limited failures at the most heavily stressed junction in the tree, which can be found by analyzing the geometry and current configuration. Our experimentally verified model for tree reliability can be used with layout tools for reliability-driven computer-aided design (RCAD), through ranking of the reliabilities of trees in order to identify areas at risk from electromigration damage.

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