Analysis of thermal stress-induced grain boundary cavitation and notching in narrow Al-Si metallizations

Li, Che‐Yu; Black, R. D.; LaFontaine, W. R.

doi:10.1063/1.100113

Cited by 73 publications

(3 citation statements)

References 9 publications

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“…However, OFF-ON is wholly different from the hillock formation for several reasons. Many studies , concerning whiskers (or hillocks) have been conducted in an effort to find methods to prevent hillock formation, which is a detrimental to the reliability of electronic packaging systems. OFF-ON can be exploited to grow perfect single-crystalline Bi nanowires for fundamental transport studies and possibly for use in thermoelectric applications.…”

mentioning

confidence: 99%

On-Film Formation of Bi Nanowires with Extraordinary Electron Mobility

Shim¹,

Ham²,

Lee³

et al. 2009

Nano Lett.

138

166

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A novel stress-induced method to grow semimetallic Bi nanowires along with an analysis of their transport properties is presented. Single crystalline Bi nanowires were found to grow on as-sputtered films after thermal annealing at 260-270 degrees C. This was facilitated by relaxation of stress between the film and the thermally oxidized Si substrate that originated from a mismatch of the thermal expansion. The diameter-tunable Bi nanowires can be produced by controlling the mean grain size of the film, which is dependent upon the thickness of the film. Four-terminal devices based on individual Bi nanowires were found to exhibit very large transverse and longitudinal ordinary magnetoresistance, indicating high-quality, single crystalline Bi nanowires. Unusual transport properties, including a mobility value of 76900 cm(2)/(V s) and a mean free path of 1.35 mum in a 120 nm Bi nanowire, were observed at room temperature.

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mentioning

confidence: 99%

On-Film Formation of Bi Nanowires with Extraordinary Electron Mobility

Shim¹,

Ham²,

Lee³

et al. 2009

Nano Lett.

138

166

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show abstract

“…Since 1984 it has been observed that voids form in A1 interconnects under a passivation layer, even under zero current density [168][169][170][171][172][173][174][175][176][177][178]. Since there is mechanlcal constraint in unpassivated interconnects, no stress voiding has been reported so far in the unpassivated lines.…”

Section: B2 Stress Induced Voiding In A1 Interconnectsmentioning

confidence: 99%

The microstructural mechanism of electromigration failure in narrow interconnects of Al alloys

Kim

1993

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Thisthesis reports a studyof themechanism ofelectromigration failure inAI-2Cu-1Si thin-film conducting lines on Si. Sampleswcrc patterned from0.5_m thick vapor-deposited films withvarious mean grain sizes (G), and had lines widths (W) of 1.3, 2,4 and 6 _m, providing aneffective linewidth (W/G) rangeofapproximately from0.5to3. The lines wereagedatvarious conditions tochangetheCu-precipitatc distribution and were then tested to failure at T = 225°C and j = 215x106 A/cm 2. Some samples were tested over a range of substrate temperatures, current densities and current reversal times. Aging produces an initially dense distribution of metastable 0' (A12Cu; coherent) in the grain interiors, with stable 0 (A12Cu; incoherent) at the grain boundaries. The intragranular 0' is gradually absorbed into the grain boundary precipitates, lowering the density of intragranular precipitates. In the wide lines (W/G > 1) the mean time to failure increases slowly and monotonically with pre-aging time and current reversal time. The failure mode is the formation and coalescence of voids that form on grain boundaries with an appa.rent activation energy of 0.65 eV. In the narrow lines (W/G < 1), the lines failed by a transgranular-slit mechanism with an activation energy near 0.93 eV, in which voids forms in the bamboo grains that terminate the longest polygranular segments in the line t i, due to accumulation of a supersaturation of vacancies. The distribution of the polygranular segments and the kinetics of failure varies with the linewidths, which provides an explanation for the dependence of failure statistics on line geometry. Failure occurs after Cu has been swept from the grains that fail. Pre-aging the line to create a more stable i distribution of Cu lengthens the time required to sweep Cu from the longest polygranular segment, and significantly increases the time to failure. In the optimum case when the density of intragranular O-phase precipitates is maximized, the transgranular-slit failure mechanism is suppressed, and the bamboo grain fails by diffuse thinning to rupture. The results from the current reversal test indicate that the time to sweep Cu in the polygranular segments is longer for longer polygranular segments, and have the consequence that the time to first failure in an array of lines is much longer than predicted by a log-normal fit to the distribution of failure times.

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“…Voids in Al lines have been seen to grow even at room temperatures [4] and the problem of thermal stress voiding is becoming more serious as line widths continue to decrease [5,6] It has been argued that void nucleation occurs, during cooldown from passivation temperatures, due to grain boundary sliding-induced stress concentrations at the intersection between a grain boundary and the passivation [6].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Thermal Stress Induced Void Growth During Thermal Cycling

et al. 1993

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Recent work in thermal stress induced voiding in passivated lines has focussed on the isothermal, quasi-steady state growth of existing voids.In this work, the transient growth and shrinkage of voids during the thermal cycling of narrow, passivated lines was studied. Analysis of experimental data for passivated lines demonstrates the quick buildup and evolution of a backstress at the grain boundary during heating and cooling. This backstress greatly reduces the driving force for void growth at higher temperatures and must be accounted for in stress induced void growth models for the case of appreciably varying temperatures in short time scales.

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Analysis of thermal stress-induced grain boundary cavitation and notching in narrow Al-Si metallizations

Cited by 73 publications

References 9 publications

On-Film Formation of Bi Nanowires with Extraordinary Electron Mobility

On-Film Formation of Bi Nanowires with Extraordinary Electron Mobility

The microstructural mechanism of electromigration failure in narrow interconnects of Al alloys

Analysis of Thermal Stress Induced Void Growth During Thermal Cycling

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