All-electrochemical synthesis of tunable fine-structured nanoporous copper films

Castillo, Ezer; Zhang, Jackson; Dimitrov, Nikolay

doi:10.1557/s43577-022-00323-4

Cited by 4 publications

(14 citation statements)

References 63 publications

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“…All-electrochemical synthesis of tunable fine-structured nanoporous copper filmsCastilloE.ZhangJ.DimitrovN. Castillo, E. Zhang, J. Dimitrov, N. MRS Bull.202247913925 …”

Section: Key Referencesmentioning

confidence: 99%

“…Crystalline Cu–Zn alloys with different compositions were achieved by controlling the metal ion concentration ratio in the plating bath (Figure ). , …”

Section: Formation Of Np-cu Filmsmentioning

confidence: 99%

“…Anodic LSV curves depicting the dealloying of Cu–Zn alloys with different composition ratios as indicated by the figure legend; scan rate = 1 mV·s –1 . Reproduced with permission from ref . Copyright 2022 Springer Nature.…”

Section: Formation Of Np-cu Filmsmentioning

confidence: 99%

“…Low- and high-magnification SEM micrographs of np-Cu formed by dealloying of Cu–Zn alloys with different compositions and their corresponding ligament size distribution. Reproduced with permission from ref . Copyright 2022 Springer Nature.…”

Section: Formation 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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“…All-electrochemical synthesis of tunable fine-structured nanoporous copper filmsCastilloE.ZhangJ.DimitrovN. Castillo, E. Zhang, J. Dimitrov, N. MRS Bull.202247913925 …”

Section: Key Referencesmentioning

confidence: 99%

“…Crystalline Cu–Zn alloys with different compositions were achieved by controlling the metal ion concentration ratio in the plating bath (Figure ). , …”

Section: Formation Of Np-cu Filmsmentioning

confidence: 99%

Section: Formation Of Np-cu Filmsmentioning

confidence: 99%

Section: Formation Of Np-cu Filmsmentioning

confidence: 99%

See 2 more Smart Citations

Copper-Based Nanomaterials for Fine-Pitch Interconnects in Microelectronics

et al. 2023

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“…Electrodeposition of Cu has been extensively studied since it plays an important role in the electroplating and microelectronic industry. − Prior to Cu bulk electrodeposition, Cu underpotential deposition (UPD) might occur when Cu–substrate interaction is stronger than the interaction among the depositing Cu atoms. The behaviors of Cu UPD on foreign metal substrates are of particular interest. − Generally, Cu UPD could form a monolayer of Cu atoms on the metallic substrate, which provides an important subject for understanding transitions from single atoms to a monolayer of condensed metal phase and also help to understand the subsequent Cu overpotential deposition (OPD) process. , In addition, UPD provides an effective way of surface modification to prepare new materials for catalysis, − the modification of nanoparticles, and other applications .…”

Section: Introductionmentioning

confidence: 99%

Unconventional Electrochemical Behaviors of Cu Underpotential Deposition in a Chloride-Based Deep Eutectic Solvent: High Underpotential Shift and Low Coverage

Tan

et al. 2023

Anal. Chem.

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The (5 × 5) Moiré pattern resulting from coadsorption of Cu atoms and chloride ions on the Au(111) electrode is one of the most classical structures for underpotential deposition (UPD) in electrochemical surface science. Although two models have been proposed to describe the pattern, the details of the structure remain ambiguous and controversial, leading to a question that remains to be answered. In this work, we investigate the UPD behaviors of Cu on the Au(111) electrode in a chloride-based deep eutectic solvent ethaline by in situ scanning tunneling microscopy (STM). Benefiting from the properties of the ultraconcentrated electrolyte, we directly image not only Cu but also Cl adlayers by finely tuning tunneling conditions. The structure is unambiguously determined for both Cu and Cl adlayers, where an incommensurate Cu layer is adsorbed on the Au(111) surface with a Cu coverage of 0.64, while the Cl coverage is 0.32 (only half of the expected value); i.e., the atomic arrangement of the observed (5 × 5) Moiré pattern in ethaline matches neither of the models proposed in the literature. Meanwhile, STM results confirm the origin of the cathodic peak in the cyclic voltammogram, which indicates that the underpotential shift of Cu UPD in ethaline indeed increases by ca. 0.40 V compared to its counterpart in a sulfuric acid solution, resulting in a significant deviation from the linear relation between the underpotential shift and the difference in work functions proposed in the literature. The unconventional electrochemical behaviors of Cu UPD reveal the specialty of both the bulk and the interface in the chloride-based deep eutectic solvent.

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Roughness Factors of Electrodeposited Nanostructured Copper Foams

Levin,

Morozov,

Frolov

et al. 2023

Nanomaterials

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Copper-based electrocatalytic materials play a critical role in various electrocatalytic processes, including the electroreduction of carbon dioxide and nitrate. Three-dimensional nanostructured electrodes are particularly advantageous for electrocatalytic applications due to their large surface area, which facilitates charge transfer and mass transport. However, the real surface area (RSA) of electrocatalysts is a crucial parameter that is often overlooked in experimental studies of high-surface-area copper electrodes. In this study, we investigate the roughness factors of electrodeposited copper foams with varying thicknesses and morphologies, obtained using the hydrogen bubble dynamic template technique. Underpotential deposition (UPD) of metal adatoms is one of the most reliable methods for estimating the RSA of highly dispersed catalysts. We aim to illustrate the applicability of UPD of lead for the determination of the RSA of copper deposits with hierarchical porosity. To find the appropriate experimental conditions that allow for efficient minimization of the limitations related to the slow diffusion of lead ions in the pores of the material and background currents of the reduction of traces of oxygen, we explore the effect of lead ion concentration, stirring rate, scan rate, monolayer deposition time and solution pH on the accuracy of RSA estimates. Under the optimized measurement conditions, Pb UPD allowed to estimate roughness factors as high as 400 for 100 µm thick foams, which translates into a specific surface area of ~6 m2·g−1. The proposed measurement protocol may be further applied to estimate the RSA of copper deposits with similar or higher roughness.

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All-electrochemical synthesis of tunable fine-structured nanoporous copper films

Cited by 4 publications

References 63 publications

Copper-Based Nanomaterials for Fine-Pitch Interconnects in Microelectronics

Copper-Based Nanomaterials for Fine-Pitch Interconnects in Microelectronics

Unconventional Electrochemical Behaviors of Cu Underpotential Deposition in a Chloride-Based Deep Eutectic Solvent: High Underpotential Shift and Low Coverage

Roughness Factors of Electrodeposited Nanostructured Copper Foams

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