Liner materials for direct electrodeposition of Cu

Lane, Michael; Murray, Conal E.; McFeely, F. R.; Vereecken, Philippe M.; Rosenberg, R.

doi:10.1063/1.1610256

Cited by 196 publications

(145 citation statements)

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“…The substrate holder is a half cylinder made of aluminum which was inserted into a stainless steel reactor tube. A cartridge heater and a thermocouple (not shown) are embedded in the substrate holder in order to heat the substrate to a temperature higher than the reactor wall by [10][11][12][13][14][15][16][17][18][19][20] • C. This arrangement favors deposition of desired film on the substrate rather than the wall and is suitable for a CVD process with a thermally activated rate. The reactor pressure during deposition was controlled automatically by a throttle valve (MKS Instruments) located downstream to the substrate holder.…”

Section: Methodsmentioning

confidence: 99%

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Chemical Vapor Deposition of Cobalt Nitride and its Application as an Adhesion-Enhancing Layer for Advanced Copper Interconnects

Bhandari

Yang

Kim

et al. 2012

ECS J. Solid State Sci. Technol.

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An interlayer of face centered cubic (fcc) Co4N has demonstrated significant improvements in adhesion between copper and diffusion barrier layers. This fcc phase of Co4N was prepared by chemical vapor deposition (CVD) using bis(N-tert-butyl-N′-ethyl-propionamidinato)cobalt(II) and a reactant mixture of NH3 and H2 at substrate temperatures from 100 to 180°C. The Co/N atomic ratio and the phase of cobalt nitride film can be modified by adjusting the ratio of NH3 and H2 in the gas feedstock. The cobalt nitride films prepared by CVD are smooth, highly conformal, and stable against intermixing with copper up to at least 400°C. This fcc cobalt nitride material has very strong adhesion to copper due to the small lattice mismatch (−1 to 2%) between fcc-Co4N and fcc Cu. Copper wires should be stabilized against failure by electromigration when fcc cobalt nitride interlayers are placed between the copper and surrounding diffusion barriers.

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Section: Methodsmentioning

confidence: 99%

“…Various studies have been conducted to examine different metals such as Ru, 10,11 Pd, 12 Pt, 13 Rh, 13 Ir, 14 Ag, 15 Os 16 or Co 17 as possible candidates for an adhesion layer to replace Ta. These more noble metals bind oxygen and fluorine less strongly than Ta does, so they are expected to adhere better to CVD Cu than Ta does.…”

mentioning

confidence: 99%

Chemical Vapor Deposition of Cobalt Nitride and its Application as an Adhesion-Enhancing Layer for Advanced Copper Interconnects

Bhandari

Yang

Kim

et al. 2012

ECS J. Solid State Sci. Technol.

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“…Ruthenium has been studied as platable barrier/liner for acid ECD Cu. [5][6][7] However, this acidic ECD Cu on Ru suffers from a strong terminal effect due to the high electrical resistivity of the Ru liner and agglomeration of Cu. 8,9 On the other hand, electroless deposition (ELD) of Cu is a wet chemical process that does not suffer from terminal effects.…”

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confidence: 99%

Nucleation Kinetics of Electroless Cu Deposition on Ruthenium Using Glyoxylic Acid as a Reducing Agent

Inoue

Philipsen

Veen

et al. 2014

J. Electrochem. Soc.

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Glyoxylic acid is seen as a promising candidate to replace formaldehyde as reducing agent in electroless Cu baths. For deposition on ruthenium, the anodic reaction of glyoxylic acid has been evaluated and compared to formaldehyde using linear sweep voltammetry. Significant differences were observed for the deposition of copper on ruthenium. First of all, a faster nucleation was inferred from open-circuit potential measurements, which is beneficial as it reduces the total process time. Secondary, we found 2,2 bipyridyl worked as stabilizer and brightener in this glyoxylic acid-based electroless bath. Thirdly, the purity of the copper films improved when 2,2 bipyridyl was present in the solution. Using the optimized composition, we demonstrate a conformal Cu seed layer deposition (∼100 nm) inside high aspect ratio (16.7) through-Si vias. This work shows the feasibility for electroless Cu seeding in a through-Si via metallization sequence.

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“…[13][14][15][16][17][18] Ru among them has been most frequently treated for next generation diffusion barrier of Cu interconnect so far. [19][20][21] We have previously reported seedless Cu electrodeposition on W and Ta diffusion barriers with regard to the nucleation and growth of Cu thin film.…”

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confidence: 99%

Surface Morphology Evolution of Cu Thin Films Electrodeposited Directly on Ti Diffusion Barrier in Citric Acid

Kim

2015

J. Electrochem. Soc.

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The formation of Cu thin film directly on Ti diffusion barrier by electrodeposition is important for next generation Cu interconnect in Si-based microelectronic devices. It depends on the surface morphology evolution of Cu deposit at the initial stage of nucleation and growth. In this study, we investigated the surface morphology evolution of Cu thin film on Ti in citric acid solution, introducing several simple ways to determine the stages of nucleation, Cu nuclei overlap, and Cu film formation with deposition time. During potentiostatic Cu deposition, studies on morphology change using the chronoamperometry, the change of surface roughness, and the change of sheet resistance and sheet resistivity are carried out along with microscopic observation. Resultant surface morphology of Cu deposit on Ti is greatly influenced by nucleation behavior, and its dependence on deposition potential is also studied in relation with the calculation of critical Cu nucleus size. According to the suggested ways, it is available to indirectly observe the transition of Cu nuclei to Cu thin film on Ti diffusion barrier during electrodeposition. Electrodeposition has been widely used to fabricate Cu interconnect in ultra large scale integrated Si microelectronic device since 1997.1 As the width of Cu interconnect line in the Si device gets shrinking under 45 nm, more sophisticated control of Cu electrodeposition process parameters is required to fill dual-damascene structures with void-free Cu. Many researchers have tried to understand the behaviors of additives like suppresser, leveler, and accelerator in electrolytes, which are valid for Cu growth control within sub-45 nm wide dual-damascene structures of the Si device.2-5 Another effort has been made to give more space for Cu fill within dual-damascene structures by eliminating a seed layer for Cu electrodeposition. It has been reported that seedless Cu electrodeposition directly on diffusion barrier is a promising approach to fabricate sub-45 nm Cu interconnect line.6-12 Cu was electrodeposited directly on non-metallic diffusion barriers such as W 2 N, TiN, and TaN. However, seedless Cu electrodeposition is moderately limited for wafer-level Cu interconnect fabrication. Significant difference of deposition current density across a Si wafer leads to the non-uniformity of thickness and microstructure of an electrodeposited Cu layer because non-metallic diffusion barrier layers have much higher electrical resistivities than a Cu seed layer.Metallic diffusion barriers, which are mostly transition metals such as Ru, W, Ta, Ti, Cr, Ni, Co, Pt, Pd, Nb, Mo, Ir, and Os, have been suggested due to their relatively high electrical conductivity, excellent resistance to Cu diffusion, and immiscible characteristic with Cu. 13-18Ru among them has been most frequently treated for next generation diffusion barrier of Cu interconnect so far. [19][20][21] We have previously reported seedless Cu electrodeposition on W and Ta diffusion barriers with regard to the nucleation and growth of Cu thin film....

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Liner materials for direct electrodeposition of Cu

Cited by 196 publications

References 1 publication

Chemical Vapor Deposition of Cobalt Nitride and its Application as an Adhesion-Enhancing Layer for Advanced Copper Interconnects

Chemical Vapor Deposition of Cobalt Nitride and its Application as an Adhesion-Enhancing Layer for Advanced Copper Interconnects

Nucleation Kinetics of Electroless Cu Deposition on Ruthenium Using Glyoxylic Acid as a Reducing Agent

Surface Morphology Evolution of Cu Thin Films Electrodeposited Directly on Ti Diffusion Barrier in Citric Acid

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