Thermal stress-induced and electromigration-induced void-open failures in Al and Al–Cu fine lines

Kwok, Thomas; Chan, K. K.; Chan, Ho Lun; Simko, J.

doi:10.1116/1.577267

Cited by 16 publications

(5 citation statements)

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“…The effects rather than vacancy relaxation effects. Finally, the measurements to date have been limited to moderate frequencies deviation in lifetime from the expected current density (<10 MHz) with the exception of Kwok et al [3], who extended dependence, characterized over IY2 orders of magnitude in the range to 200MHz. Unfortunately, their lowest frequency current density, is explained in terms of a shift in the boundary was 50 MHz, which makes it difficult to compare that work to condition for electromigration as the current density is decreased, other studies.…”

mentioning

confidence: 99%

Wafer-level pulsed-DC electromigration response at very high frequencies

Pierce

Snyder

Swanson

et al. 1994

Proceedings of 1994 IEEE International Reliability Physics Symposium RELPHY-94

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mentioning

confidence: 99%

Wafer-level pulsed-DC electromigration response at very high frequencies

Pierce

Snyder

Swanson

et al. 1994

Proceedings of 1994 IEEE International Reliability Physics Symposium RELPHY-94

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“…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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“…Recently such a relationship has been suggested from results of cxperiments appearing in the literature. [6,7] History During a pre-qualification investigation of a new multi-level metal process, erratic electromigration performance was discovered during the testing of metal at the second level. In many cases, second metal (M2) performed below requirements, whereas first level metal (Ml) and third level metal (M3) were quite satisfactoiy even though the metal systems were similar.…”

Section: Introductionmentioning

confidence: 99%

<title>Thermally induced stresses and electromigration failure</title>

et al. 1993

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Attempts to improve the reliability of narrow passivated Al/Cu conductors as defmed by the performance in an accelerated electromigration test are reviewed. The results are explained in terms of the effect of thermally induced stress and stress voiding on electromigration lifetime. Other processing variations which produced small or inconsequential changes are also discussed. In addition, it was observed that electromigration perfonnance in samples susceptible to stress voiding was degraded as a function of storage time at room temperature.

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Thermal stress-induced and electromigration-induced void-open failures in Al and Al–Cu fine lines

Abstract: Articles you may be interested inStress-induced and electromigration voiding in nitride passivated Al interconnects AIP Conf. Proc. 491, 174 (1999); 10.1063/1.59906In situ transmission electron microscopy study of plastic deformation and stress-induced voiding in Al-Cu interconnects

Cited by 16 publications

References 0 publications

Wafer-level pulsed-DC electromigration response at very high frequencies

Wafer-level pulsed-DC electromigration response at very high frequencies

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

<title>Thermally induced stresses and electromigration failure</title>

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