Effect of CoWP cap thickness on via yield and reliability for Cu interconnects with CoWP-only cap process

Gambino, Jeff; Wynne, J.; Smith, Sharon L.; Mongeon, S.; Pokrinchak, P.; Meatyard, D.

doi:10.1109/iitc.2005.1499944

Cited by 4 publications

(4 citation statements)

References 3 publications

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“…Because the current depended on temperature, and J=E was proportional to ffiffiffi ffi E p , the conduction mechanism was considered to be PF emission through trap states such as diffused Cu ions. 31) However, the leakage current did not depend on the temperature at the times close to the breakdown, as observed in Figs. 11(a) and 11(b), which present Fowler-Nordheim (FN) plots of the leakage current at the times close to the breakdown for n-Si and p-Si, respectively.…”

Section: Comparison Of Tddb Characteristics Between N-si and P-simentioning

confidence: 64%

“…23) In our CoWP barriers, there was no thickness dependence of the barrier properties, which indicates that our CoWP has no barrier properties against Cu diffusion even though other studies have reported that CoWP has barrier properties against Cu diffusion. 20,[29][30][31][32] The reason for this difference is considered to be due to the compositional difference and the crystallization between our CoWP and those samples used in the other studies. The surface roughnesses of the 10 and 40 nm CoWP=NiB films were 2.23 and 2.67 nm, respectively, as determined by AFM measurements, and the roughness values were less than the total thickness; therefore, the film coverage should not be the reason.…”

Section: Resultsmentioning

confidence: 91%

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Reliability tests of electroless barriers against copper diffusion under bias-temperature stress with n- and p-type substrates

Ueno¹,

Fujishima²,

Yamashita³

et al. 2016

Jpn. J. Appl. Phys.

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To investigate the similarity and difference of substrate conduction type in the time-dependent dielectric breakdown (TDDB) tests for the barrier integrity against Cu diffusion under bias-temperature stress (BTS), the TDDB reliability of electroless NiB and CoWP/NiB was determined by metal oxide semiconductor (MOS) structures on n-type Si (n-Si) substrates, and the test results were compared with those using p-type Si (p-Si) substrates. The TDDB results and mechanism were observed to be qualitatively the same as Cu diffusion for both conduction types. However, the TDDB lifetime using p-Si was found to be potentially shorter because of the reverse bias conditions than that using n-Si under the forward bias conditions.

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Section: Comparison Of Tddb Characteristics Between N-si and P-simentioning

confidence: 64%

Section: Resultsmentioning

confidence: 91%

Reliability tests of electroless barriers against copper diffusion under bias-temperature stress with n- and p-type substrates

Ueno¹,

Fujishima²,

Yamashita³

et al. 2016

Jpn. J. Appl. Phys.

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“…The film composition determined by XPS was as follows: Co, 97%; W, 1%; and P, 2%. In previous research on electroless plated CoWP as a metal cap, the composition were as follows: Co, 91%; W, 3%; and P, 6% for one sample [24][25][26] and Co, 89.4%; W, 2.4%; and P, 8.2% for another sample. 27) It was reported that there were barrier properties of CoWP in 400 14) or 500 C 27) annealing.…”

Section: Tddb Characteristics Of Ebls and Osmlmentioning

confidence: 99%

Barrier Integrity of Electroless Diffusion Barriers and Organosilane Monolayer against Copper Diffusion under Bias Temperature Stress

Mitsumori¹,

Fujishima²,

Ueno³

2012

Jpn. J. Appl. Phys.

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Barrier integrity of electroless NiB and CoWP/NiB thin layers against copper (Cu) diffusion was evaluated by time-dependent dielectric breakdown (TDDB) under bias temperature stress (BTS) using metal oxide semiconductor (MOS) test structures. The BTS tests were carried out also for an approximately 2.2-nm-thick organosilane monolayer (OSML), which has been used as the underlayer of the electroless barrier layers (EBLs). It was found that the barrier integrity of the EBLs was NiB 40 nm > NiB 10 nm > CoWP/NiB 40 nm = CoWP/NiB 10 nm in this order. The field acceleration parameter of the TDDB lifetime was almost the same for all EBLs. Initial failures and wide lifetime distributions were observed for CoWP/NiB when the NiB catalyst layer for CoWP was not thick enough, which is considered to be due to the large surface roughness. In addition, the OSML was found to have some barrier properties. Although the reliability of OSML was inferior to electroless NiB and CoWP/NiB barrier layers, it is considered that the barrier integrity of the EBLs was partially supported by the OSML.

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“…CoWP having the resistance of Cu diffusion was formed with the electroless deposition in the upper part of the trench in order to eliminate the passivation layer arranged on the trench wiring. 5,6 SiOC having a dielectric constant lower than SiO 2 was used as a chemical mechanical polishing ͑CMP͒ cap to decrease k eff between interconnects. 7,8 The CMP-cap film was used as a sacrificial film and thinned by polishing.…”

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confidence: 99%

Recovery Processes of CMP-Induced Damages for Copper/Porous Silica Damascene Interconnects

Ishikawa

Shishida

Yamanishi

et al. 2007

J. Electrochem. Soc.

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This paper describes the effects of recovery processes for the degradation caused by chemical mechanical polishing ͑CMP͒ in the integration of Cu/porous silica low-k material interconnects ͑Cu/po-SiO͒, in which SiOC is used as CMP-Cap film ͑Cap-SiOC͒ for po-SiO film. The leakage current and capacitance between Cu damascene interconnects increased when Cap-SiOC was removed by CMP and the po-SiO was exposed, because the surfactant in CMP chemicals penetrated the po-SiO and the hydrophobicity of the po-SiO decreased, resulting in the increase of water absorption in the po-SiO. As a result of the recovery process after CMP, the leakage current has decreased by three orders of magnitude by applying an isopropyl alcohol rinse and 1,3,5,7-tetramethylcyclo-tetrasiloxane ͑TMCTS͒ gas treatment, and the capacitance has decreased by 15% by applying the TMCTS gas treatment.

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Effect of CoWP cap thickness on via yield and reliability for Cu interconnects with CoWP-only cap process

Cited by 4 publications

References 3 publications

Reliability tests of electroless barriers against copper diffusion under bias-temperature stress with n- and p-type substrates

Reliability tests of electroless barriers against copper diffusion under bias-temperature stress with n- and p-type substrates

Barrier Integrity of Electroless Diffusion Barriers and Organosilane Monolayer against Copper Diffusion under Bias Temperature Stress

Recovery Processes of CMP-Induced Damages for Copper/Porous Silica Damascene Interconnects

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