Underpotential deposition of copper and silver on polycrystalline ruthenium electrodes

Huong, C. Nguyen Van; González-Tejera, M.J.

doi:10.1016/0022-0728(88)80108-6

Cited by 28 publications

(33 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Charge integration for the voltage sweep from +0.28 V to −0.25 V corresponding to the broad peak yields a charge density of ∼240 μC/cm 2 , which is in agreement with reported charge densities of Ru surface oxide reduction. 12,13 The significant cathodic current observed at potentials negative to −0.30 V is hydrogen evolution catalyzed by Ru. In the presence of Pb +2 in the electrolyte, the broad peak around −0.14 V is attributed to Pb upd on Ru.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Communication—Underpotential Deposition of Lead for Investigating the Early Stages of Electroless Copper Deposition on Ruthenium

Akolkar

2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

We investigated the early stages of electroless copper (Cu) deposition onto ruthenium (Ru) using a novel ex situ electrochemical technique involving underpotentially deposited lead (Pb upd ). The fractional surface coverage of Cu during electroless deposition on Ru was measured via the Pb upd deposition charge. Recognizing that the onset potential for Pb upd is surface-sensitive, the fraction of the exposed Ru substrate and that of the electroless Cu covered substrate could be quantitatively measured. Our investigation, while providing a convenient and easy-to-use surface analytical method, supports the two-dimensional electrochemical growth mode of Cu during early stages of electroless Cu nucleation on Ru. Continued interconnect scaling because of device miniaturization presents numerous challenges to current state-of-the-art dual damascene process flow.1 As interconnect dimensions shrink, void-free filling using conventional Cu electrodeposition becomes increasingly difficult due to the poor step coverage of the non-conformally sputtered Cu seed layer.2 To overcome this challenge, alternative metallization approaches are under development, such as direct electroless Cu deposition on Ru liners.3-5 Electroless Cu deposition on Ru provides uniform deposit distribution (lack of terminal effects) on large-area wafers. However, insights into electro-nucleation phenomena during thin-film fabrication via electroless Cu deposition on Ru are still lacking. In a recent report by Inoue et al., 4 smooth electroless Cu films in the ∼100 nm thickness range were deposited on Ru. Kim et al. 3 investigated the electroless Cu growth process on Ru using atomic force microscopy and linear sweep voltammetry. These investigators suggested that, in the early stages of electroless Cu nucleation, twodimensional (2D) growth of Cu monolayers is favored on Ru.In this paper, we applied an ex situ electrochemical technique based on Pb upd to further understand the early stages of electroless Cu deposition on Ru. Recognizing that the onset potential for Pb upd is surface-sensitive, we achieved selective Pb upd on Ru-covered or Cucovered portions of a substrate's surface. Coulometry measurements during selective Pb upd formation provided fractional surface coverage of Cu on Ru as a function of the electroless deposition time. Our investigation provides a convenient surface analytical method while providing further evidence for the 2D electrochemical growth mode during electroless Cu deposition on Ru. ExperimentalElectroless Cu deposition.-Electroless Cu deposition was performed onto Si wafers pre-coated with a barrier layer (2 nm PVD-Ta) and a Ru liner layer (2 nm PVD-Ru). Before electroless Cu deposition, the Ru-coated substrates were rinsed with ethanol and deionized (DI) water. The substrates were then immersed in a solution containing 1.5 M dimethylamine borane (DMAB, 98+%, Acros Organics) at 60• C for 1 min to remove Ru surface oxides. 6 After pretreatment, the substrates were rinsed with de-oxygenated DI water for 10 s before immer...

show abstract

Section: Resultsmentioning

confidence: 99%

“…As expected, the stripping charge density increases linearly with deposition time indicating a steady deposition rate. Using charge density of 0.6 mC/cm 2 for one Cu monolayer, 12 the measured charge density in Fig. 2 was converted into the equivalent number of Cu monolayers.…”

Section: Resultsmentioning

confidence: 99%

Communication—Underpotential Deposition of Lead for Investigating the Early Stages of Electroless Copper Deposition on Ruthenium

Akolkar

2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…A number of electrochemical [177][178][179][180] and vacuum studies [181,182] of initial stages of Cu deposition on Ru have shown complete wetting with epitaxial and strained monolayer(s) at the initial stage followed by Stranski-Krastanov growth mode at higher thickness. Underpotential Cu monolayer (UPD) formation prior to the bulk deposition [177][178][179][180] is deemed a unique feature of Pt-based barrier layers because of its ability to serve as a wetting layer for subsequent Cu growth. UPD of Cu has been used as an analytical tool for roughness and morphology characterization of Ru (oxide-free) surface as well as an indicatior of the surface oxidation state [172,180].…”

Section: New Barrier Materialsmentioning

confidence: 99%

“…Electrodeposition of Cu activated by a monolayer oxide reduction electrode results in the formation of Cu UPD monolayer [177] (Fig. 27.35b).…”

Section: New Barrier Materialsmentioning

confidence: 99%

Applications to Magnetic Recording and Microelectronic Technologies

Brankovic¹,

Vasiljević²,

Dimitrov³

2010

Modern Electroplating

View full text Add to dashboard Cite

Early applications of electrodeposition in manufacturing were mainly confined to situations where relatively thick polycrystalline metal deposits were needed. These included protective or sacrificial metal layers for corrosion protection, decorative applications, and situations where metal coatings with specific mechanical properties were needed [1]. However, development of theoretical foundations in electrochemical engineering and electrometallurgy and the sophistication of the tools used for electrodeposition have contributed to widespread electrodeposition in high-tech industry where more rigorous thickness control of the deposit is required. Nowadays, electrodeposition is recognized as a mature deposition method for the fabrication of magnetic thin-film heads [2, 3] and in microelectronics and microelectromechanical system (MEMS) technologies [4][5][6][7]. The most recent developments suggest that electrodeposition is an attractive fabrication process for many emerging fields of nanotechnology. These new applications make the future of electrodeposition research a seemingly interesting and quite exciting endeavor.In this chapter we will review the most important electrodeposition processes used for fabrication of magnetic recording heads and in microelectronics technology. The most important parameters, criteria, and phenomena controlling the deposit morphology and properties are highlighted and discussed using the examples from the authors' own work and from the work of other prominent groups around the world. MAGNETIC RECORDINGNowadays electrodeposition is used for the fabrication of many important parts of magnetic recording heads, including magnetic shields and poles, Cu coils, and for connecting Cu studs, leads and pads, Au interconnects, and nonmagnetic gaps and coatings. Some of these electrodeposition processes and bath chemistries were adopted from other technologies as a common practice. However, the fabrication of the writing pole in magnetic recording heads has been the most important manufacturing step where electrodeposition has gained its fame as a cost-effective, reliable, and high-throughput operation (Fig. 27.1a). Over the years, the development of magnetic reader technologies, recording medias and the geometry of the magnetic recording process have posed many challenges that electrodeposition had to meet in order to stay competitive with other deposition methods. The common requirement for the alloys for magnetic pole fabrication is that they have low coercivity (softness), low magnetostriction (l % 0), and relatively high magnetic moment. The electrodeposition process of these alloys has to be scalable with high-throughput manufacturing with minimum effort in process control and reproducibility. The bath chemistry has to be stable over the time and compatible with other materials and processes used in through-mask fabrication.In the very beginning, the electrodeposited magnetic alloy for magnetic pole application was Ni 81 Fe 19 -Permalloy (inductive read heads)-with saturation magnetic fl...

show abstract

“…Desta maneira, este método fornece rapidamente dados termodinâmicos e cinéticos básicos, sendo bastante adequado para a detecção de pequenas quantidades de espécies reativas. Assim, não é surpresa a grande quantidade de trabalhos publicados nesta área utilizando como técnica experimental eletroquímica básica a voltametria cíclica [21][22][23][24][25][26][27][28][29] . No entanto, Swathirajan et al 13 contestam o uso de técnicas eletroquímicas que utilizam apenas um eletrodo de trabalho para este tipo de estudo, pois postulam que o conjunto de dados resultantes não é suficiente para separar os fluxos de massa e de carga no eletrodo.…”

Section: Técnicas Eletroquímicas Utilizadas Nos Estudos Da Drsunclassified

Estudos da eletrodeposição de metais em regime de subtensão

Santos¹,

Machado²,

Avaca³

et al. 2000

Quím. Nova

View full text Add to dashboard Cite

Recebido em 2/7/99; aceito em 24/9/99 Keywords: underpotential deposition; ad-atoms; adsorption. STUDIES OF THE UNDERPOTENTIAL DEPOSITION OF METALS. This work reviews recent studies of underpotential deposition (UPD) of several metals on Pt and Au substrates performed in the Grupo de Materiais Eletroquímicos e Métodos Eletroanalíticos (IQSC -USP, São Carlos DIVULGAÇÃO INTRODUÇÃOEm eletrocatálise, o conceito de sítio ativo na superfície eletródica é de fundamental importância. O número e a disposição geométrica dos centros de adsorção normalmente determinam o mecanismo da reação em estudo, assim como a natureza do produto formado 1 . Um exemplo da influência da natureza do sítio ativo no mecanismo da reação pode ser encontrado na reação de redução do oxigênio. Sobre superfícies que disponham de dois centros de adsorção vizinhos separados por uma determinada distância, onde a molécula de oxigênio possa se adsorver numa estrutura tipo ponte, a reação ocorre com a transferência de quatro elétrons, resultando em água como o produto formado. Isto ocorre por exemplo sobre Pt 2,3 . Por outro lado, a falta da distância ideal entre os centros de adsorção leva, normalmente a adsorção da molécula a ocorrer da forma linear, sobre apenas um sítio, e a reação resulta na formação de água oxigenada, com a transferência de apenas dois elétrons, como ocorre sobre Au 4 . Desta forma, a alteração, de maneira controlada, do número e da distância entre os centros de adsorção na superfície eletródica possibilita o planejamento de substratos catalíticos para determinadas reações de interesse.Uma das maneiras mais adequadas de se obter a modificação controlada da natureza dos sítios ativos da superfície de um eletrodo é pela deposição em subtensão de metais. A deposição em subtensão de átomos metálicos, M, em um substrato diferente, S, tem atraído um enorme interesse nas últimas dé-cadas [5][6][7][8][9] . Basicamente, o fenômeno da deposição em regime de subtensão está relacionado com a possibilidade de se depositar até uma monocamada de um dado metal, M, em potenciais mais positivos do que aquele relacionado com o equilíbrio M z+ / M (potencial de Nernst). Esta aparente violação da lei de Nernst tem como explicação o excesso de energia da ligação entre o átomo adsorvido (frequentemente chamado de ad-átomo) e o substrato (S-M ads ) em relação à energia de ligação entre um átomo depositado em uma superfície do próprio metal (M-M ads ) 10 :O deslocamento positivo do pico de deposição em subtensão, ∆E, pode ser desde alguns milivolts até algumas centenas de milivolts, dependendo da intensidade das interações entre o adátomo e o substrato.A deposição em subtensão pode ser descrita por uma equação eletroquímica do tipo 11 :onde λ é o coeficiente de transferência parcial de carga, introduzido por Lorenz e Salié 12 e υ o número estequiométrico. O primeiro parâmetro leva em consideração o fato de que a transferência de carga ocorre em uma etapa elementar não integral durante a eletrossorção. A carga parcial dos ad-átomos é normalmente muito pequ...

show abstract

Underpotential deposition of copper and silver on polycrystalline ruthenium electrodes

Cited by 28 publications

References 29 publications

Communication—Underpotential Deposition of Lead for Investigating the Early Stages of Electroless Copper Deposition on Ruthenium

Communication—Underpotential Deposition of Lead for Investigating the Early Stages of Electroless Copper Deposition on Ruthenium

Applications to Magnetic Recording and Microelectronic Technologies

Estudos da eletrodeposição de metais em regime de subtensão

Contact Info

Product

Resources

About