Analysis of electromigration induced early failures in Cu interconnects for 45nm node

Arnaud, L.; Cacho, F.; Doyen, L.; Terrier, F.; Galpin, D.; Monget, C.

doi:10.1016/j.mee.2009.06.014

Cited by 19 publications

(5 citation statements)

References 14 publications

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“…A weakened adhesion renders the deposited Cu to debond from a substrate, and accelerates Cu diffusion via free surface or substrate interface, also giving reduced values of activation energy for EM. 35,36 Our previous study has shown that the adhesion strength of as-deposited Cu films on an APTMS-SAM on SiO 2 is significantly higher than that of unpassivated Cu films on SiO 2 , 6.1 vs 27.6 MPa; the adhesion strength of the SAM-passivated Cu films after annealing is markedly increased from 27.6 to 72.6 MPa. 37 The extraordinarily high adhesion strength, along with the high barrier capability of the orderly SAM, should be highly effective in retarding copper diffusion through surface and interface, which thus are unlikely to be the dominant mechanisms for the failure of the SAM-encapsulated Cu interconnects.…”

Section: Resultsmentioning

confidence: 97%

Enhancement of Electromigration Reliability of Electroless-Plated Nanoscaled Copper Interconnects by Complete Encapsulation of a 1 nm-Thin Self-Assembled Monolayer

Chen¹,

Lee²,

Cheng³

et al. 2022

J. Electrochem. Soc.

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The downsizing of integrated circuits for the upcoming technology nodes has brought attention to sub-2 nm thin organic/inorganic materials as an alternative to metallic barrier/capping layers for nanoscaled Cu interconnects. While self-assembled monolayers (SAMs) serving as the barrier materials for copper metalized films are well studied, electromigration (EM) of Cu interconnects encapsulated by SAMs is an untouched research topic. In this study, we report an all-wet encapsulating process involving SAM seeding/encapsulating and electroless narrow-gap filling to fabricate nanoscaled copper interconnects that are completely encapsulated by a 1 nm-thin amino-based SAM, subsequently annealed to some extents prior to EM testing. Both annealing and SAM encapsulation retard EM of the Cu interconnects tested at current densities on orders of 108–109 A cm−2. Particularly, SAM encapsulation quintuples the lifetime of, for example, as-fabricated Cu interconnects from 470 to 2,890 s. Electromigration failure mechanisms are elucidated from analyses of activation energies and current-density scale factors obtained from the accelerated EM testing. The importance of SAM qualities (e.g., ordering and layered structure) as a prerequisite for the reliability enhancement cannot be overestimated, and the results of the SAM quality evaluation are presented. The mechanism of reliability enhancement is also thoroughly discussed.

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Section: Resultsmentioning

confidence: 97%

Enhancement of Electromigration Reliability of Electroless-Plated Nanoscaled Copper Interconnects by Complete Encapsulation of a 1 nm-Thin Self-Assembled Monolayer

Chen¹,

Lee²,

Cheng³

et al. 2022

J. Electrochem. Soc.

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“…Further scaling increases resistivity 4 and failure rates by electromigration. 5 Electromigration is a thermally activated process, and therefore, selfheating properties are of importance. CNTs could help reduce heating of interconnects, which in modern chips consume up to 50% of the total power 3 and allow for higher current densities than conventional copper interconnects.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Copper interconnects are currently reaching their limit of miniaturization. Further scaling increases resistivity and failure rates by electromigration . Electromigration is a thermally activated process, and therefore, self-heating properties are of importance.…”

Section: Introductionmentioning

confidence: 99%

Thermal Conductivity of a Supported Multiwalled Carbon Nanotube

et al. 2019

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We have extracted temperature-dependent thermal conductivity values from scanning thermal microscopy measurements of a self-heated multiwalled carbon nanotube supported on a silicon substrate. A deliberately introduced segment of amorphous carbon served as an integrated nanoheater. Kelvin probe force microscopy was used to supplement the thermometry data with values for the nanotube’s electrical resistivity. This way, both the spatially resolved temperature rise and the Joule heating power density were available for further analysis. A one-dimensional heat diffusion model was fitted to the data to extract values for the thermal conductivity along the nanotube axis and the thermal conductance between the nanotube and supporting substrate. We found thermal conductivity values that continuously increase from 200 to 400 W m–1 K–1 in a temperature range of 100 to 400 K above room temperature. The values obtained are about one order of magnitude lower compared to values reported for the freely suspended case. We attribute this observation to the increased phonon scattering and quenching of acoustic phonon modes due to the substrate interaction.

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“…In particular, increasing current density in back end of line (BEOL) interconnects has led to premature chip failure from electromigration-induced Cu diffusion. Material interfaces, such as the Cu-interlayer dielectric (ILD) barrier interface, have been demonstrated as accelerated pathways for Cu electromigration (EM). − Consequently, Cu EM challenges are an important focus of BEOL materials research. ,− To improve device lifetimes, EM can be reduced by alloying of Cu interconnects but depositing thin EM resistant metal caps on the metallization lines is preferred due to large resistivity increases associated with alloying. , As device scaling continues to the 7 nm node and beyond, capping layers will likely be necessary to mitigate Cu EM. Co makes an effective capping material and is less expensive than alternatives such as Ru. , …”

Section: Introductionmentioning

confidence: 99%

XPS Investigation of the Atomic Layer Deposition Half Reactions of Bis(N-tert-butyl-N′-ethylpropionamidinato) Cobalt(II)

Elko-Hansen

Ekerdt

2014

Chem. Mater.

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Adsorption of the atomic layer deposition (ALD) precursor bis(N-tert-butyl-N′-ethylpropionamidinato) cobalt(II) (CoAMD) on SiO 2 , carbon-doped oxide (CDO), and Cu is reported. Adsorption was performed under ALD cycling conditions with and without H 2 coreactant to mimic the first and second ALD half reactions on the substrates. Resultant surface chemistries were evaluated by X-ray photoelectron spectroscopy. Adsorption of CoAMD proved self-limiting and the precursor reduced readily on Cu with and without H 2 coreactant to form Co 0 . Residual C and N signals on Cu suggest that amidinate ligands and decomposition fragments from CoAMD adsorb on the Cu surface. On SiO 2 and CDO, CoAMD chemisorbs on O containing moieties, primarily OH, to form Co 2+ . Accumulation of Co after three ALD cycles was greatest on Cu and least on CDO.

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Analysis of electromigration induced early failures in Cu interconnects for 45nm node

Cited by 19 publications

References 14 publications

Enhancement of Electromigration Reliability of Electroless-Plated Nanoscaled Copper Interconnects by Complete Encapsulation of a 1 nm-Thin Self-Assembled Monolayer

Enhancement of Electromigration Reliability of Electroless-Plated Nanoscaled Copper Interconnects by Complete Encapsulation of a 1 nm-Thin Self-Assembled Monolayer

Thermal Conductivity of a Supported Multiwalled Carbon Nanotube

XPS Investigation of the Atomic Layer Deposition Half Reactions of Bis(N-tert-butyl-N′-ethylpropionamidinato) Cobalt(II)

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