Comparison of Cu electromigration lifetime in Cu interconnects coated with various caps

Hu, C.‐K.; Gignac, L.; Liniger, E.; Herbst, B.; Rath, D.L.; Chen, S. T.; Kaldor, S.; Simon, A.; Tseng, Wei–Tsu

doi:10.1063/1.1596375

Cited by 119 publications

(76 citation statements)

References 6 publications

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“…Most research efforts to increase EM reliability have focused on slowing mass transport at the top interface to extend the median lifetime , Meyer 2002, Hu 2003a, Hu 2003b, Hu 2004 It is clear that the median time-to-failure as well as the activation energy of the diffusion process depend directly on the EM mass transport mechanism. Thus, improving the top interface which serves as the major diffusion path appears to be the most promising approach to enhance EM performance with regard to these parameters.…”

Section: Recent Em Improvementsmentioning

confidence: 99%

“…, Hu 2003a, Hu 2003b, Hu 2004. The major focus of these studies is the effect of an interface change on the EM mass transport mechanism.…”

Section: Influence Of Passivation Layermentioning

confidence: 99%

“…Such efforts include the insertion of a thin layer of CoWP between Cu and the passivation layer , Hu 2003a, Hu 2003b, Hu 2004, as well as alloying Cu with small percentages of aluminum . While these studies focus on reducing interfacial mass transport to improve the lifetime and possibly the activation energy, a better understanding of sigma is still needed.…”

Section: Timementioning

confidence: 99%

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Statistical Analysis of Electromigration Lifetimes and Void Evolution for Cu Interconnects

Hauschildt

Gall²,

Thrasher³

et al. 2004

MRS Proc.

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Electromigration (EM) failure statistics and the origin of the lognormal deviation (σ) for Cu interconnects have been investigated by analyzing the lifetime statistics and void size distributions at various stages during EM testing. Experiments were performed on 0.18 μm wide Cu interconnects with tests terminated after specific amounts of resistance increases, or after a specified test time. Void size distributions of resistance-based, as well as time-based EM tests were obtained using focused ion beam (FIB) microscopy. The lifetime and void size distributions were found to follow lognormal distribution functions. The σ values of EM lifetime and time-based void size distributions decrease with higher percentages of resistance increase, reaching an asymptotic value of σ ∼ 0.14. In contrast, σ values of resistance-based void size distributions are significantly smaller and do not show an obvious dependence on time. The statistics of resistance-based void size distributions can mainly be accounted for by geometrical variations of the void shape, while the statistics of time-based void size distributions requires consideration of kinetic aspects of the EM process. The σ values of EM lifetime distributions at long times can be simulated based on measured void size distributions, taking into account geometrical and experimental factors of EM. In contrast, for short times the statistics of initial void formation and the kinetics of interfacial mass transport have to be considered.

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Section: Recent Em Improvementsmentioning

confidence: 99%

“…, Hu 2003a, Hu 2003b, Hu 2004. The major focus of these studies is the effect of an interface change on the EM mass transport mechanism.…”

Section: Influence Of Passivation Layermentioning

confidence: 99%

Section: Timementioning

confidence: 99%

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Statistical Analysis of Electromigration Lifetimes and Void Evolution for Cu Interconnects

Hauschildt

Gall²,

Thrasher³

et al. 2004

MRS Proc.

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“…An activation energy of 1.4 eV for damascene Cu conductors in contact with Ta on all four sides is also available in the literature. 10 The activation energy for TaN/Cu/TaN is remarkably low, on the other hand. We have not been able to find any result for similar configurations in the literature.…”

Section: -3 Mardanimentioning

confidence: 99%

“…8 But less information is available regarding the role of the commonly used TaN and Ta liner materials when it comes to integrity and reliability of the Cu interconnect. 9,10 The purpose of this work is to elucidate the pros and cons of Cu films stacked by these materials with respect to resistance to EM and electrical integrity at elevated temperatures. In order to shed some light on the role of interfaces, we focus on both symmetrically and asymmetrically layered systems, i.e., TaN/Cu/TaN and TaN/Cu/ Ta, respectively.…”

Section: Introductionmentioning

confidence: 99%

Electromigration behavior of Cu metallization interfacing with Ta versus TaN at high temperatures

Mardani

Norström

Smith

et al. 2016

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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High-temperature stability of Cu-based interconnects is of technological importance for electronic circuits based on wide band gap semiconductors. In this study, different metal stack combinations using Ta or TaN as capping-and/or barrier-layer, in the configuration cap/Cu/barrier, are evaluated electrically and morphologically prior to and after high-temperature treatments. The symmetric combinations Ta/Cu/Ta and TaN/Cu/TaN are characterized by a low and stable sheet resistance after annealing up to 700 C. Asymmetric combinations of Ta/Cu/TaN and TaN/Cu/Ta, however, display an increase in sheet resistance values after annealing at 500 C and above. This increase in sheet resistance is considered to result from Ta diffusion into the grain boundaries of the Cu film. The preliminary electromigration studies on the TaN/Cu/Ta and TaN/Cu/TaN structures show a twofold higher activation energy and a tenfold longer lifetime for the former, thus suggesting an important role of the interface between Cu and the cap and/or barrier.

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Electrochemical Processing Tools for Advanced Copper Interconnects: An Introduction

Datta¹

2009

Advanced Nanoscale ULSI Interconnects: Fundamentals and Applications

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Comparison of Cu electromigration lifetime in Cu interconnects coated with various caps

Cited by 119 publications

References 6 publications

Statistical Analysis of Electromigration Lifetimes and Void Evolution for Cu Interconnects

Statistical Analysis of Electromigration Lifetimes and Void Evolution for Cu Interconnects

Electromigration behavior of Cu metallization interfacing with Ta versus TaN at high temperatures

Electrochemical Processing Tools for Advanced Copper Interconnects: An Introduction

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