Selective Electroless Metal Deposition for Integrated Circuit Fabrication

Ting, C. H.; Paunović, Milan

doi:10.1149/1.2096654

Cited by 102 publications

(51 citation statements)

References 8 publications

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“…Thin film copper deposition technologies for ultra-large scale integrated technology (ULSI) are being intensively investigated and electroless-plating is one of the routes explored [1][2][3][4][5][6][7][8][9]. Indeed copper offers low specific resistance and high resistance to electromigration [2,3].…”

Section: Introductionmentioning

confidence: 99%

Electroless deposition of copper in acidic solutions using hypophosphite reducing agent

Touir¹,

Larhzil²,

EbnTouhami³

et al. 2005

J Appl Electrochem

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A new bath formulation was developed, which allowed deposition of copper-rich Cu-Ni-P alloys in electroless acidic solutions in the absence of formaldehyde. The reducing agent was sodium hypophosphite. Though cupric ions do not catalyse the oxidation of hypophosphite, we show that, in the presence of a low concentration of Ni(II) species, it is possible, even at low pHs, to induce the reduction of the cupric species. A very strong preferential deposition of copper was observed, which gives Cu-Ni-P layers with copper content up to 97 wt%. The phosphorus content decreased from 13% to 1% with increasing copper content. The plating rate decreased when the copper sulfate concentration in the solution increased. It increased with increasing pH or temperature, but the influence was less pronounced than in alkaline solutions. Compact layers were obtained with a nodular morphology which did not markedly changed with composition.

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Section: Introductionmentioning

confidence: 99%

Electroless deposition of copper in acidic solutions using hypophosphite reducing agent

Touir¹,

Larhzil²,

EbnTouhami³

et al. 2005

J Appl Electrochem

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“…[1][2][3] An important goal in producing interconnection lines which are highly reliable is to achieve films which have as large a grain size as possible, as well as being free from voids. 4) Plating methods are capable of achieving large grain sizes in Cu lines, but even in annealed films, a distribution of smaller grain sizes exists.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Grain and Micro-Void Structure in Electroplated Copper Interconnects

et al. 2002

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A detailed investigation has been carried out into the evolution of grain size and grain orientation in electroplated Cu interconnection lines. The specimens were annealed to produce a range of different grain size distributions. Very accurate grain size distributions were obtained from extensive TEM observations of a large number of specimens, followed by computer tracing of grain boundaries. Although annealing causes the average grain size to increase, very small grains are found to persist in the distribution, even when the average grain size is large. These small grains have been investigated in detail to determine the reason for their thermal stability. In addition, the occurrence and redistribution of small micro-voids has been investigated for wafers with different grain sizes. These voids are believed to be associated with seams which are formed in the Cu lines during plating.

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“…For an example of potential applications, we show one-step electrodeposition Pd film on dielectric layers to fabricate conductometric hydrogen gas sensor without transferring Pd film. 8 and so on. Electrochemical methods 9,10 allow the solution process under fine and easy control without reducing agents by directly delivering electrons to precursors.…”

mentioning

confidence: 97%

Direct Electrodeposition of Thin Metal Films on Functionalized Dielectric Layer and Hydrogen Gas Sensor

Lee

Shin

Lee

et al. 2016

J. Electrochem. Soc.

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Harnessing cathodic hydrogen atom generation, metals such as Pt, Pd, Cu, Au and Ni are directly electrodeposited on functionalized dielectric layers of 6 nm thick silicon oxide formed by thermal oxidation of c-Si substrate. Modifying the oxide layer with functional molecules and Au nanoparticles by simple wet chemistry, we can enhance electrodeposition efficiently and thereby electroplate nanoparticles of Pd and Pt to obtain such thin metal films. In particular, Au nanoparticles on amine-modified silicon oxides remarkably enhance electrodeposition of metal nanoparticles to create sturdy metal films on the dielectric layer, n + -Si/SiO 2 -NH 2 . Such enhancement is ascribed to good affinity of Au nanoparticles with electrodeposited metal as well as enhanced current density across the silicon oxide. For an example of potential applications, we show one-step electrodeposition Pd film on dielectric layers to fabricate conductometric hydrogen gas sensor without transferring Pd film. 8 and so on. Electrochemical methods 9,10 allow the solution process under fine and easy control without reducing agents by directly delivering electrons to precursors. Importantly, it can create stabilizer-free NPs or films with pristine surfaces that potentially serve as catalytically active sites for sensors and chemical reactions.11 Therefore, electroplating method has been widely considered as a cost-effective alternative. Especially, electro-synthesis of nanoparticles on conducting surfaces 12,13 has been attracting steady attention as highlighted by shape-control of nanoparticles using the programmed electrochemical methods on glassy carbon electrode. 14 Despite its valuable merits, programmed electro-synthesis can produce nanoparticles on the conducting electrode, while need to be transferred to other substrates, mostly dielectric materials, for practical applications in many cases. Recently reported strategy gives an inspiration of direct electrodeposition on dielectric layer; Pd NPs deposited on n + -Si/thermal SiO 2 . 15 It appears to be counterintuitive to electroplate on insulating substrates but it works owing to electrogenerated hydrogen (H) atoms in the thermal SiO 2 layer. H atom-mediated electro-reduction on thermal SiO 2 layers can be finely controlled by not only the applied bias but also pH in the solution, producing pristine Pd NPs deposited without any stabilizer or additive. H atoms, which are created by reduction of protons migrating across thermal SiO 2 layers, are expected to make precursors reduced at the interface between SiO 2 and solution. Indeed, this suggests a new breakthrough toward direct electroplating technology for thin metal films on dielectric layer.There are a few critical issues to overcome. Low density of current carried by H atoms and poor affinity of metal onto pristine SiO 2 are likely to make the metal grow too slow to be a film. Furthermore, there is a limitation in uniformity of particles in terms of both size and shape. For fine and steady control of electroplating process, it is undesir...

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Selective Electroless Metal Deposition for Integrated Circuit Fabrication

Cited by 102 publications

References 8 publications

Electroless deposition of copper in acidic solutions using hypophosphite reducing agent

Electroless deposition of copper in acidic solutions using hypophosphite reducing agent

Evolution of Grain and Micro-Void Structure in Electroplated Copper Interconnects

Direct Electrodeposition of Thin Metal Films on Functionalized Dielectric Layer and Hydrogen Gas Sensor

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