Electromigration early-failure distribution

Hoang, Hong Hai; Nikkel, E. L.; McDavid, J. M.; MacNaughton, R. B.

doi:10.1063/1.343038

Cited by 21 publications

(2 citation statements)

References 6 publications

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“…Only a few studies have been performed which extend the test sample size beyond the typical number of several tens of failure units. [1][2][3] In this study, an approach has been undertaken to gain information about the statistical behavior of many thousand interconnects and to investigate possible deviations from perfect lognormal statistics. A Wheatstone Bridge arrangement and large arrays of 480 interconnects were used to prove that deviations did not occur down to a cumulative failure of about 1 out of 20 000.…”

Section: Introductionmentioning

confidence: 99%

Statistical analysis of early failures in electromigration

Gall

Capasso

Jawarani

et al. 2001

Journal of Applied Physics

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The detection of early failures in electromigration (EM) and the complicated statistical nature of this important reliability phenomenon have been difficult issues to treat in the past. A satisfactory experimental approach for the detection and the statistical analysis of early failures has not yet been established. This is mainly due to the rare occurrence of early failures and difficulties in testing of large sample populations. Furthermore, experimental data on the EM behavior as a function of varying number of failure links are scarce. In this study, a technique utilizing large interconnect arrays in conjunction with the well-known Wheatstone Bridge is presented. Three types of structures with a varying number of Ti/TiN/Al(Cu)/TiN-based interconnects were used, starting from a small unit of five lines in parallel. A serial arrangement of this unit enabled testing of interconnect arrays encompassing 480 possible failure links. In addition, a Wheatstone Bridge-type wiring using four large arrays in each device enabled simultaneous testing of 1920 interconnects. In conjunction with a statistical deconvolution to the single interconnect level, the results indicate that the electromigration failure mechanism studied here follows perfect lognormal behavior down to the four sigma level. The statistical deconvolution procedure is described in detail. Over a temperature range from 155 to 200 °C, a total of more than 75 000 interconnects were tested. None of the samples have shown an indication of early, or alternate, failure mechanisms. The activation energy of the EM mechanism studied here, namely the Cu incubation time, was determined to be Q=1.08±0.05 eV. We surmise that interface diffusion of Cu along the Al(Cu) sidewalls and along the top and bottom refractory layers, coupled with grain boundary diffusion within the interconnects, constitutes the Cu incubation mechanism.

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Section: Introductionmentioning

confidence: 99%

Statistical analysis of early failures in electromigration

Gall

Capasso

Jawarani

et al. 2001

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…Only few studies have been performed which extend the test sample size beyond the typical number of several 10 failure units. [1][2][3] In this study, an approach has been undertaken to gain information about the statistical behavior of many thousand interconnects and to investigate possible deviations from perfect lognormal statistics. A Wheatstone Bridge arrangement and large arrays of several 100 interconnects were used to prove that deviations did not occur down to a failure probability of about 1 out of 20 000.…”

mentioning

confidence: 99%

Detection and analysis of early failures in electromigration

Gall

Capasso

Jawarani

et al. 2000

Applied Physics Letters

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The early failure issue in electromigration (EM) has been an unresolved subject of study over the last several decades. A satisfying experimental approach for the detection and analysis of early failures has not been established yet. In this study, a technique utilizing large interconnect arrays in conjunction with the well-known Wheatstone Bridge is presented. A total of more than 20 000 interconnects were tested. The results indicate that the EM failure mechanism studied here follows lognormal behavior down to the four sigma level.

show abstract