Filling in nanoporous gold with silver via bulk deposition and surface-limited redox replacement approaches

Castillo, Ezer; Xie, Yunxiang; Dimitrov, Nikolay

doi:10.1016/j.electacta.2021.138196

Cited by 6 publications

(12 citation statements)

References 62 publications

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“…As mentioned earlier, to facilitate the formation of Cu 6 Sn 5 at a low enough temperature and prevent a premature nucleation of Cu 3 Sn IMC, the targeted Sn fraction was set at an overall 50 at % or more. In our previous work, we described an approach of electrochemical coating processes including either conventional overpotential deposition (OPD) or electrochemical atomic layer deposition by surface limited redox replacement (SLRR) . While the OPD method resulted in the growth of three-dimensional features on the np substrate surface, flatter, nearly contiguous coatings were obtained using SLRR.…”

Section: Sn-coating Of Np-cu Filmsmentioning

confidence: 98%

“… Filling in nanoporous gold with silver via bulk deposition and surface-limited redox replacement approachesCastilloE.XieY.DimitrovN. Castillo, E. Xie, Y. Dimitrov, N. Electrochim. Acta2021380138196 …”

Section: Key Referencesmentioning

confidence: 99%

“…The cross-section images reveal the interpenetrated porosity of np-Au before filling. A progressive, homogeneous filling is observed as the number of SLRR cycles increased …”

Section: Sn-coating Of Np-cu Filmsmentioning

confidence: 99%

“…Sequential cross-section SEM micrographs showing the progressions of Ag filling of (a) pristine np-Au via SLRR after (b) 15 cycles, (c) 30 cycles, and (d) 40 cycles. Reproduced with permission from ref . Copyright 2021 Elsevier.…”

Section: Sn-coating Of Np-cu Filmsmentioning

confidence: 99%

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Copper-Based Nanomaterials for Fine-Pitch Interconnects in Microelectronics

et al. 2023

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Conspectus Nanostructured copper-based materials have emerged as a new generation of robust architectures for realizing high-performing and reliable interconnection in modern electronic packaging. As opposed to traditional interconnects, nanostructured materials offer better compliance during the packaging assembly process. Due to the high surface area-to-volume ratio of nanomaterials, they also enable joint formation by sintering through thermal compression at much lower temperatures compared to bulk counterparts. Nanoporous Cu (np-Cu) films have been employed in electronic packaging as materials that facilitate a chip-to-substrate interconnection, realized by a Cu-on-Cu bonding after sintering. In this Account, we discuss the use of self-supported np-Cu films for low-temperature joint formation. The novelty of this work comes from the incorporation of tin (Sn) into the np-Cu structure, thus ensuring lower sintering temperatures with a goal of producing Cu–Sn intermetallic alloy-based joints between two Cu substrates. The incorporation of Sn is done using an all-electrochemical bottom-up approach that involves the conformal coating of fine-structured np-Cu (initially formed by dealloying of Cu–Zn alloys) with a thin layer of Sn. This Account provides insight on existing technologies for using nanostructured films as materials for interconnects as well as the optimization studies for the Sn-coating processes as a new alternative approach. The applicability of the synthesized Cu–Sn nanomaterials for low-temperature joint formation is also discussed. To realize this new approach, the Sn-coating process is administered by a galvanic pulse plating technique, which is optimized to preserve the porosity in the structure with a Cu/Sn atomic ratio that allows for the formation of the Cu6Sn5 intermetallic compound (IMC). Nanomaterials obtained using this approach are subjected to joint formation by sintering at temperatures between 300 and 200 °C under 20 MPa pressure in forming gas atmosphere. Cross-section characterization of the formed joints postsintering reveals densified bonds with minimal porosity that consist predominantly of the Cu3Sn IMC. Furthermore, these joints are less prone to structural inconsistencies compared to existing joints formed using purely np-Cu. The results presented in this Account provide a glimpse into a facile and cost-effective approach for synthesizing nanostructured Cu–Sn films and illustrate their applicability as new interconnect materials.

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Section: Sn-coating Of Np-cu Filmsmentioning

confidence: 98%

Section: Key Referencesmentioning

confidence: 99%

“…The cross-section images reveal the interpenetrated porosity of np-Au before filling. A progressive, homogeneous filling is observed as the number of SLRR cycles increased …”

Section: Sn-coating Of Np-cu Filmsmentioning

confidence: 99%

Section: Sn-coating Of Np-cu Filmsmentioning

confidence: 99%

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Copper-Based Nanomaterials for Fine-Pitch Interconnects in Microelectronics

et al. 2023

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“…The use of cryoaerogels as electrocatalysts with multimodal porosity is still in its infancy: first, we have demonstrated recently the enhanced electrocatalytic activity of cryoaerogels and cryohydrogels consisting of small Au, Pd, and Pt nanoparticles over their dried nanoparticle films . As another alternative, nanoporous gold and silver have also been developed and their advantageous electrocatalytic properties in ethanol oxidation reaction (EOR) and glucose sensing were proven. − Nanorods (NRs) are underrepresented in these studies, due to their larger size, more complex preparation route, and most importantly the scarcity of synthesis routes providing high enough nanorod concentrations. However, since the pioneering works of Murphy , and El-Sayed, novel routes have been discovered to prepare highly monodisperse, tailorable gold and silver nanorods using additives to break the symmetry. , While gold nanorods can be synthesized in the well-known seeded growth method, this is not applicable for silver nanorods.…”

Section: Introductionmentioning

confidence: 99%

Noble-Metal Nanorod Cryoaerogels with Electrocatalytically Active Surface Sites

Zámbó

Rusch

Lübkemann

et al. 2021

ACS Appl. Mater. Interfaces

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Noble-metal-based electrocatalysts usually contain small nanoparticle building blocks to ensure a high specific surface area as the scene for the surface processes. Here, we show that relatively large noble-metal nanorods are also promising candidates to build up functional macrostructures with prominent electrocatalytic activity. After optimizing and upscaling the syntheses of gold nanorods and gold bipyramid-templated silver nanorods, cryoaerogels are fabricated on a conductive substrate via flash freezing and subsequent freeze drying. The versatile cryoaerogelation technique allows the formation of macrostructures with dendritic, open-pore structure facilitating the increase of the accessible nanorod surfaces. It is demonstrated via electrochemical oxidation and stripping test experiments that noble-metal surface sites are electrochemically active in redox reactions. Furthermore, gold nanorod cryoaerogels offer a platform for redox sensing, ethanol oxidation reaction, as well as glucose sensing. Compared to their simply drop-cast and dried counterparts, the noble-metal nanorod cryoaerogels offer enhanced activity due to the open porosity of the fabricated nanostructure while maintaining structural stability.

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