Substrate and pretreatment dependence of Cu nucleation by metal–organic chemical vapor deposition

Kwak, Sung Kwan; Chung, Kwansoo; Lim, H.

doi:10.1016/s1567-1739(02)00065-2

Cited by 10 publications

(3 citation statements)

References 18 publications

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“…27,[44][45][46] The effect of the VTMS inhibitor on copper growth is very distinct from that of NH 3 on growth of HfB 2 on SiO 2 from Hf(BH 4 ) 4 , in which the density of nuclei increased continuously with time. 18 Evidently, in the latter system, nucleation is not directed by surface defects.…”

Section: Resultsmentioning

confidence: 98%

“…We cannot deduce from the present data what factor(s) control the absolute density of Cu islands on the air-exposed Ru surface, but it is possible that a pre-existing density of surface defects, which may be a function of the surface preparation, accounts for the observed island density. 27,[44][45][46] The effect of the VTMS inhibitor on copper growth is very distinct from that of NH 3 on growth of HfB 2 on SiO 2 from Hf(BH 4 ) 4 , in which the density of nuclei increased continuously with time. 18 Evidently, in the latter system, nucleation is not directed by surface defects.…”

Section: Resultsmentioning

confidence: 99%

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Chemical Vapor Deposition of Copper: Use of a Molecular Inhibitor to Afford Uniform Nanoislands or Smooth Films

Babar

Davis

Zhang

et al. 2014

ECS J. Solid State Sci. Technol.

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We report a method to control the surface morphology of thin copper films during growth by chemical vapor deposition from the precursor Cu(hfac)VTMS. A molecular inhibitor -an additive that modifies the surface attachment kinetics but does not decompose and contribute impurity atoms to the film -is added during the nucleation and/or growth stages of the film. Here we show that the reaction by-product VTMS can serve as such an inhibitor. If the inhibitor is added during the nucleation stage, when bare substrate surface is still exposed, the inhibitor greatly reduces the rate of coalescence and promotes the formation of a large density of uniformly-sized copper islands. Alternatively, if the film is allowed to nucleate in the absence of the inhibitor, subsequent addition of the inhibitor leads to a continuous copper film that is remarkably smooth on the nm scale. © 2014 The Electrochemical Society. [DOI: 10.1149/2.009405jss] All rights reserved.Manuscript submitted January 14, 2014; revised manuscript received February 27, 2014. Published March 11, 2014 Copper is used in many advanced nanoscale technologies due to its high electrical and thermal conductivity, and its strong surface plasmon resonance when in the form of nanoparticles.1-5 For continuous films, such as those used as the seed layer for electrodeposition in integrated circuits, the film must be less than 10 nm thick, pinholefree, and extremely smooth, with an rms roughness of less than 1 nm. For optical devices based on copper nanoparticles, it is important to control the nanoparticle size and morphology. 4,6 Rigorous control of copper growth can be difficult: the surface energy of copper is high and the atomic diffusion rate is significant, so that dewetting often occurs during growth or subsequent annealing. 7-12Thin films of copper can be deposited by a wide variety of techniques including wet chemical growth, physical vapor deposition, chemical vapor deposition (CVD) and atomic layer deposition (ALD). To deposit copper conformally in substrate architectures such as trenches and vias that have re-entrant or high aspect ratio features, ALD and CVD are preferred techniques because of the ability of the precursor molecules to diffuse throughout the structure.13-17 A general difficulty arises when the substrate is relatively unreactive, such as an oxide surface: the resulting films tend to be rough owing to a combination of sparse nucleation and the tendency of the deposited material to agglomerate. 18 Once surface roughness on the length scale of the island separation is formed, it cannot be eliminated by the overgrowth of more material. 18The use of additives to enhance film smoothness is well established in the electrochemical deposition of copper 19,20 but is not common in CVD. For CVD, the morphology of copper films can sometimes be improved by adding a second component to the growth gas. For example, addition of H 2 O to a flux of Cu(hfac)VTMS (hfac = hexafluoroacetylacetonate and VTMS = vinyltrimethylsilane) enhances the wettability of the surfac...

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Chemical Vapor Deposition of Copper: Use of a Molecular Inhibitor to Afford Uniform Nanoislands or Smooth Films

Babar

Davis

Zhang

et al. 2014

ECS J. Solid State Sci. Technol.

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show abstract

“…It is well known that the activation barrier for the disproportionation reaction is high on SiO 2 and CDO compared to that on metals or semiconductors because conductive surfaces catalyze the reaction via charge exchange. 31 Thus Cu(hfac) on a metallic surface (air-exposed Ru or Cu) will disproportionate at a finite rate to afford Cu metal, 32 whereas on insulating surfaces (SiO 2 or CDO), Cu(hfac) will predominantly recombine with the VTMS inhibitor and desorb as Cu(hfac)VTMS. This huge difference in kinetic rates then affords selective growth.…”

Section: Resultsmentioning

confidence: 99%

Surface-Selective Chemical Vapor Deposition of Copper Films through the Use of a Molecular Inhibitor

Babar

Mohimi

Trinh

et al. 2015

ECS J. Solid State Sci. Technol.

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We report a simple process for the selective deposition of copper films on RuO 2 , while no Cu nucleation occurs on thermal SiO 2 or porous carbon doped oxide (CDO). Using the precursor Cu(hfac)VTMS, selectivity is attained by adding a co-flow of excess VTMS to act as a growth inhibitor. With precursor alone, 52 nm of Cu grows on RuO 2 ; on CDO or on thermal SiO 2 , nucleation is delayed such that 41 or 1.3 nm are deposited, respectively. Repeating the experiment with the co-flow of VTMS affords a 12 nm thick Cu film on RuO 2 with roughness of 1.8 nm. But on CDO or thermal SiO 2 , the Cu deposition is only 0.10 or ∼0.04 nm, respectively. AFM scans of the CDO and SiO 2 surfaces are identical to the bare substrates. The small quantity of Cu that is deposited must be finely distributed, presumably on defect sites; it can be etched to below the RBS detection limit using a co-flow of Hhfac and VTMS for few minutes at the end of the growth. The process window is wide: selective growth occurs for a range of VTMS pressures (0.5-2.0 mTorr), growth times (up to 90 min), and growth temperatures (up to 180 • C).

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Effect of hydrogen atmosphere in Cu thin film growth by chemical vapor deposition using Cu(dmamb)2

Choi

Lee

Park

et al. 2012

Microelectronic Engineering

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Substrate and pretreatment dependence of Cu nucleation by metal–organic chemical vapor deposition

Cited by 10 publications

References 18 publications

Chemical Vapor Deposition of Copper: Use of a Molecular Inhibitor to Afford Uniform Nanoislands or Smooth Films

Chemical Vapor Deposition of Copper: Use of a Molecular Inhibitor to Afford Uniform Nanoislands or Smooth Films

Surface-Selective Chemical Vapor Deposition of Copper Films through the Use of a Molecular Inhibitor

Effect of hydrogen atmosphere in Cu thin film growth by chemical vapor deposition using Cu(dmamb)2

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