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Through-glass vias (TGVs) have been extensively researched due to the unique properties of glass, including low dielectric constant, high transparency, high mechanical, thermal and chemical resistance, and low cost. The TGVs are typically filled with Cu by electrodeposition to make electrical connections in high-performance electronics with 3D integration. The Cu electrodeposition process employed to fill the through-holes is similar to the one used for printed circuit boards (PCBs), and defect-free Cu can be achieved with a butterfly filling mechanism. This study introduces the defect-free Cu filling of TGVs using polyvinylpyrrolidone (PVP) as a leveler. The effects of PVP molecular weight on the formation of suppression layers on the Cu surface was examined by electrochemical analyses. It was found that the smaller PVP (10,000 g/mol) was beneficial, forming a more compact suppression layer. In contrast, the layer of larger PVPs (360,000 g/mol) contained a large number of defects where the accelerator could adsorb, resulting in conformal electrodeposition. As a result, the PVP with a molecular weight of 10,000 g/mol led to defect-free butterfly filling at TGVs with increasing the filling performance by 20% compared to the larger PVP.

The development of high-performance electrocatalysts for methanol oxidation is an urgent task to enhance the efficiency of direct methanol fuel cells. We report a simple and controllable method to fabricate Pt-decorated TiN electrocatalysts using self-terminated electrodeposition at room temperature and ambient pressure. Under optimized deposition parameters such as electrolyte pH, TiN substrate pretreatment, and pulsed deposition potential, quenching of the Pt electrodeposition facilitates obtaining an extremely low Pt mass loading (0.93 μg/cm2) on the TiN substrate. Repeated deposition potential pulses enable a gradual increase in Pt loading, with a precise control of the loaded Pt mass. Maximum intrinsic and mass activities for the methanol oxidation reaction are achieved for the catalyst with a Pt loading mass of 55.0 μg/cm2, prepared by 20 deposition pulses. The maximum intrinsic activity achieved with the Pt-decorated TiN electrocatalyst is five times higher than that obtained with bulk Pt. The present results thus provide a facile method for the fabrication of cost-effective electrocatalysts.

In this study, the composition-optimized Pd–Cu catalyst for electrochemical N2O reduction in highly alkaline solution was prepared by a galvanic displacement method. The atomic ratio of Pd to Cu in Pd–Cu bimetallic catalyst, which has been known to be hardly controlled using galvanic displacement, was tailored by varying the concentration of citric acid in galvanic displacement bath. With increasing citric acid concentration, the decreased grain size, characterized by X-ray diffraction, and the increased amount of carbon in Pd–Cu catalyst, measured by energy-dispersive X-ray spectrometry, revealed the incorporation of citric acid into the catalyst, which was attributed to the tunable catalyst composition. The incorporation of citric acid into Pd–Cu deposit restrained the diffusion of Cu from Cu substrate to deposit, leading to decrease in the Cu content in Pd–Cu. The electrocatalytic activity for N2O reduction was strongly dependent on the Pd/Cu composition in Pd–Cu catalysts. Among the investigated Pd–Cu catalysts with different compositions, the highest electrocatalytic activity was obtained with Pd60Cu40 with a Tafel slope of 0.096 V dec−1. Moreover, the Pd60Cu40 catalyst showed remarkably enhanced mass-specific activity for N2O reduction, compared with a commercial Pd/C. The density functional theory (DFT) calculations revealed that the highest N2O reduction activity of Pd60Cu40 could be attributed to the facilitation of an adsorption/desorption balance for N2O reduction, resulting from the appropriately lowered d-band center of catalyst.

Cu foil has widely been used as a current collector for Li ion batteries due to its excellent electrical, mechanical properties and facile fabrication process, but improvement in the properties of Cu foil is necessary for continuous development of the Li ion battery. Thinner and stronger Cu foil is being demanded, and the self-annealing of Cu foil needs to be prevented for effective control of properties as well as higher productivity of the fabrication process. We investigated the effects of three additives, 2-mercapto-5-benzimidazole sulfonic acid (2M5S), polyethylene glycol (PEG), and bis (3-sulfopropyl) disulfide (SPS), on the mechanical properties and self-annealing phenomenon of Cufoil. Cu foil deposited with PEG shows the highest tensile strength and elongation after electrodeposition; however, it experiences severe self-annealing for 48 hrs. On the contrary, 2M5S and SPS reduce the self-annealing phenomenon with their incorporation into Cu film, while the initial mechanical properties are worse than those with PEG. Therefore, combinations of additives are investigated to obtain both higher mechanical properties and excellent resistance against self-annealing. Finally, 10 µm-thick Cu foil having a tensile strength of 673 MPa and an elongation of 2.9% without self-annealing can be fabricated using PEG-2M5S-SPS.

Herein, we fabricate heterostructured copper oxide nanowires decorated with amorphous Sn by Cu anodization and Sn electrodeposition for a potential application as anode in Li-ion battery. In general, Sn experiences a pulverization caused by the stress from a severe volume change during the reaction with Li-ion. Therefore, the stress should be certainly mitigated. A nanowire with 1-D structure could be a candidate anode material because it accommodates the volume change and enlarges the surface area of electrode. Yet Sn nanowire still suffers the harsh stress, copper oxide is employed as an active anode material as well as a structural framework in the present study. By virtue of the Li-conversion mechanism of copper oxide, the as-prepared Sn-decorated copper oxide nanowire exhibits an improved discharge capacity and maintains it as high as 633.0 mAh g−1 at extended cycles (77.7% of initial capacity at 150th cycle). From a rate capability experiment, the nanowire electrode presents the capacity of 424 mAh g−1 at 16 C, and shows a moderate recovering ability. The 1-D heterogeneous structure and Cu nodes that are intentionally formed during electrochemical fabrication helps realizing a cell configuration without a binder and a conducting agent, which ultimately contributes to increase energy and power density of Li-ion battery.

Through silicon via (TSV) is one of the most important technologies in 3-dimensional wafer/chip stacking. However, there are some issues related to defect-free TSV filling and Cu pumping. In this study, a defect-free TSV filling was achieved using iodide ions. The working mechanism of iodide ions in TSV filling was systemically investigated by electrochemical measurements; It was found that the formation of CuI on the electrode surface is a key process for inhibiting Cu ion reduction. This inhibition effect of iodide ions enables defect-free TSV filling. Furthermore, the study of microstructure of the filled Cu revealed that the electrochemical reduction of CuI during the TSV filling forms small Cu grains in TSV. The small Cu grains cause Cu pumping in subsequent processes, which damages semiconductor devices. We achieved a defect-free TSV filling with enlarged Cu grains using a two-step filling method that effectively promotes the direct reduction of Cu ions rather than electrochemical reduction of CuI.

Electrodeposition of Cu-based alloys has been researched for a variety of applications due to Cu-based alloys having superior properties compared to pure Cu, including higher chemical resistance, mechanical hardness, and electrocatalytic activity. Cu-Ag is the most electrically conductive among Cu-based alloys, and it has higher mechanical hardness and oxidation resistance compared to pure Cu. Cu-Ag co-deposition in cyanide-based electrolytes has been previously reported; however, the toxicity of cyanide limited its use. In this study, we introduce an ammonium hydroxide-based electrolyte for Cu-Ag electrodeposition and the properties of Cu-Ag films deposited in this electrolyte. Electrochemical measurements were performed to determine the potential range for co-electrodeposition of Cu and Ag, and the effect of nitrate reduction on the film deposition was examined. The effects of deposition potential and concentration of Ag ions in the electrolytes on the electrical resistivity and Ag contents of the films were investigated. The modulation of Ag ion concentration was found to be a more effective way to control Ag contents in the deposited films. Co-deposition of 4 at% Ag with Cu in the ammonium-hydroxide electrolyte markedly improved mechanical hardness and oxidation resistance compared to a pure Cu film without severe deterioration of electrical conductivity.

Electrocatalysis is a key part of renewable energy conversion in the future energy system. Sustainable energy conversion and chemical production require catalyst structure with high activity, durability, and product selectivity. In general, nanoscale electrocatalysts suffer various degradation phenomena during electrocatalysis, which leads to critical performance loss. Recently, the various hybrid nanostructures (such as ordered structure, metal/carbon encapsulation, or metal/metal oxide) have been highly investigated to achieve promising catalytic performances and enhanced stabilities. In this presentation, we will cover three different types of nanomaterials as highly active and stable electrocatalysts for oxygen reduction reaction (ORR). First, the alloy nanoparticles with ordered structures exhibit novel catalytic properties from their unique electronic and geometric structures. In particular, Pt alloys with atomically ordered crystal structures have been found to largely improve both electrocatalytic activity and stability for ORR through increased electronic interaction between Pt and other transition metals. Similarly, we recently demonstrated that well-controlled Co-, Mn- and Fe-based ternary or binary oxide nanocatalysts have an exceptionally high ORR activity, in addition to the promising electrocatalytic stability. Therefore, it is very important to synthesize well-ordered alloy nanocrystals to obtain highly durable and active electrocatalysts with respect to their structural and compositional properties. Second, we will show the strategic employment of carbon shells on electrocatalyst surfaces to enhance stability in the electrochemical process. Carbon shells can beneficially shield catalyst surfaces from electrochemical degradation and physical agglomeration. Thus carbon shells can effectively preserve the initial active site structure during electrocatalysis. The carbon shell also provides a confined environment at interfaces, enabling unconventional electrochemical behaviors. Finally, we will suggest an effective strategy to construct metal/oxide interfaces, precisely modulating the metal/oxide interfacial interactions in the nanoscale. By controlling the interface and strain effect on catalytic activity, we can achieve high active and stable metal oxide systems for ORR. We would like to describe the details of the above results, for investigating structure-activity relationships in electrocatalytic processes. Only when we start to comprehend the fundamentals behind electrocatalysis on the structure and interface of metal/metal oxide nanocrystals, they can be further advanced to be sustainable in long-term device operation.

The activity of electrocatalysts can be improved by modifying their electronic structures and surface morphologies. In electrochemical reactions with gas evolution, the performance of an electrocatalyst is also affected by how easily gas bubbles depart from an electrocatalyst surface. However, it is difficult to quantitatively estimate the improvement in the performance that can be achieved by promoting the departure of gas bubbles from the electrocatalyst surface. This study investigated the effect of surface hydrophilicity on the hydrogen evolution reaction (HER). The water contact angles of the nickel phosphorous (NiP) films were controlled from 40.3 to 77.2° with imperceptible differences in their intrinsic electronic structures and surface areas. Electrochemical analyses and in situ visualization of the gas evolution on the NiP films indicated that an increase in the hydrophilicity of the electrocatalysts reduced the size of gas bubbles formed on the NiP films and shortened the duration of the bubbles' stay on the NiP surface. A faster gas departure enabled continuous participation of the electrocatalyst surface in hydrogen evolution, leading to a stable electrochemical behavior of the electrocatalyst and a decrease in the overpotential at a given current density. A full-cell test revealed that the enhancement of hydrogen bubble departure on a hydrophilic NiP surface with a contact angle of 40.3° reduced the overpotential by 134 mV at a current density of 100 mA/cm2 compared to a more hydrophobic film with a contact angle of 77.2°.

The adsorption equilibria and kinetics of propane and propylene on zeolite 13X pellets were investigated by a piezometric sorption method at 283–363 K and vacuum to 650 kPa for propane and 750 kPa for propylene. The difference of the adsorption capacity between the two gases was not so great, the saturation capacity being measured at 2.95 mol/kg for propane and 3.34 mol/kg for propylene. However, it was observed clearly that propylene was more strongly adsorbed on 13X than propane upon looking into the isotherms and comparing the isosteric heats of adsorption. Dual-site Langmuir model could fit the experimental adsorption isotherm data well. Subsequently, its temperature-dependent parameters were extracted, enabling to make use of the isotherm model in designing a non-isothermal adsorption separation process. To extract the apparent reciprocal diffusion time constants, two different kinetic models were applied to the experimental uptake curves: a piezometric model suitable for the first uptake measured at the very low pressure close to zero and a non-isothermal sorption model for uptakes in the range of 10–40 kPa. The resultant apparent reciprocal diffusion time constants exhibited a strong dependency on the pressure, corresponding to the effective intercrystalline reciprocal diffusion time constants theoretically estimated by Knudsen diffusivity and the secant of isotherm. This confirmed the presumption that diffusions of propane and propylene into the 13X pellet were controlled by the intercrystalline diffusion.

In this study, the role of octylphenol ethoxylate (Triton X-100) surfactant as a suppressor in Cu electrodeposition has been examined. The inhibition ability of Triton X-100 was qualitatively and q...

The slow kinetics of the oxygen evolution reaction (OER) and the high cost of the precious metal catalysts for the OER limit the efficiency and cost-effectiveness of water splitting. In this study, we introduce electrodeposited nickel-copper-phosphorous (NiCuP) as an efficient OER electrocatalyst in alkaline medium. The addition of Cu into the NiP electrocatalyst significantly enhanced the OER activity. Optimization of the electrodeposition conditions revealed that Ni59Cu19P9 in terms of atomic percent exhibited the best activity with a reduced Tafel slope and charge transfer resistance for the OER, compared to NiP. The Ni59Cu19P9 catalyst successfully endured the OER operation at 10 mA/cm2 for up to 30 h while maintaining a Faradaic efficiency of over 99%. The X-ray photoelectron spectroscopy showed that the amount of active Ni hydroxide (NiOOH) species increased with the addition of Cu, which likely contributed to the enhanced of catalytic activity.

Dendritic Ag (a CO2-to-CO reduction catalyst) has been synthesized on carbon paper (CP) using pulse electrodeposition to fabricate a gas diffusion electrode. A combination of sonication and pulse deposition facilitated mass transfer of Ag ions to the CP, enlarging the catalyst active surface area without significantly changing the Ag crystalline structure. The current density of CO2 reduction was proportional to the surface area of dendritic Ag. Further improvements in performance were achieved by adding polyethylene glycol to the CO2 reduction cell catholyte that removed the CO gas bubbles produced at the electrode surface. The fabrication methods presented herein suggest an effective gas diffusion electrode for application in the membrane-electrode-assembly-type single cell for electrochemical CO2 reduction.

Organic additives play an important role in regulating film growth and properties in Cu electrodeposition. 3‑Mercapto‑1‑propane sulfonate (MPS) and its dimer bis(3‑sulfopropyl) disulfide (SPS) are representative accelerators that promote Cu electrodeposition rate. In this study, the formal reduction potential of SPS to MPS was determined by measuring the equilibrium constants of thiol–disulfide interchange reactions with the reference thiol/disulfide pairs by 1H nuclear magnetic resonance (1H NMR) spectroscopy. The calculated formal reduction potential of SPS to MPS was 0.153 V (vs. standard hydrogen electrode). Based on this calculation, the cell potentials of Cu(I)(thiolate) formation reaction with either SPS or MPS, which is a key reaction in accelerating mechanism, were also estimated by ultraviolet–visible absorption and 1H NMR spectroscopies: they were found to be 0.202 V and 0.214 V for SPS and MPS, respectively. The positive cell potential indicates that the formation of Cu(I)(thiolate) complexes is thermodynamically favorable in the presence of additives.

A simple one-pot method is reported for the fabrication of uniform wrinkled silica nanoparticles (WSNs). Rapid cooling of reactants at the appropriate moment during synthesis allowed the separation of nucleation and growth stages, resulting in uniform particles. The factors affecting particle size and interwrinkle distance were also investigated. WSNs with particle sizes of 65–400 nm, interwrinkle distances of 10–33 nm, and surface areas up to 617 m2 g–1 were fabricated. Furthermore, our results demonstrate the advantages of WSNs over comparable nonporous silica nanospheres and fumed silica-based products as an abrasive material in chemical mechanical planarization processes.

The intrinsic solubility of a gaseous substance and its dissolution rate play important roles in carrying out electrochemical reaction of gaseous reactant, in addition to the activity of catalyst. We tried to increase the solubility and dissolution rate of N2O by introducing Taylor vortices using a Couette-Taylor flow (CTF) mixer and investigated how the enhanced N2O dissolution affected the electrochemical reduction of N2O. The solubility and saturation time were estimated by electrochemical measurement of N2O concentration in the electrolyte solution. It was found that the Taylor vortices could not only increase the solubility of N2O but also reduce the time required to saturate the electrolyte with N2O. Furthermore, a high N2O conversion rate via electrochemical reduction was obtained with the introduction of Taylor vortices. We proved that an enhanced solubility and dissolution rate of the gaseous substance could be attained by using a CTF mixer as one of the alternatives for enhancing the electrochemical reaction of a gaseous substance in an aqueous electrolyte solution.

This study introduces the role of machine learning in improving the electrochemical analyses for the simultaneous quantifications of multiple chemicals. Here, Cu electrolyte containing Cl− and polyethylene glycol as additives was employed as a model analyte. These additives, which are redox-inactive when adsorbed onto the surface of an electrode, significantly affect Cu redox reactions. Conventional analyses cannot reveal the detailed dynamic changes in these additives owing to inherently weak signals and interference between the adsorbates. Thus, this study demonstrates how a combination of electrochemical analyses and neural network-based machine learning can identify and quantify four different additives from a single voltammogram, overcoming the present limitations. Further, instead of simply increasing the amount of data for training, chemical treatment is applied based on an understanding of Cu–adsorbate interactions to improve the performance of machine learning-based analyses. The developed method can also advance the simultaneous electrochemical analyses of other multicomponent systems.

Noble metal electrocatalysts can simply be prepared via galvanic displacement method on a sacrificial substrate, which is advantageous for preparing a uniform and thin catalyst layer. However, it is difficult to control the morphology of deposited metals via galvanic displacement, therefore, there is a limitation to increase the surface area of electrocatalysts. In this study, we demonstrate galvanic displacement for controlling the morphology of Pd, Pt, and Au from planar to whisker shapes by manipulating the dissolution rate of the sacrificial Cu substrate and the mass transport of noble metal ions. The acceleration of the dissolution of sacrificial substrate increases the reduction rate of noble metal, which develops a steep concentration gradient of noble metal ions near the surface of substrate. This induces the selective deposition of noble metal to form a whisker instead of smooth film. To verify the advantage of whisker-type catalysts, the ethanol oxidation with Pd is investigated. Whisker-type Pd shows 21 times higher electrocatalytic performance than planar Pd due to larger surface area. Therefore, it can be suggested that whisker-type catalysts simply prepared by galvanic displacement is applicable for various electrocatalytic reactions.

For the electrochemical reduction of CO2 to CO, a dendrite-type Ag catalyst was fabricated via an electrodeposition method in an ammonia-based Ag deposition solution containing ethylenediamine (EN) as an additive. The influence of electrodeposition parameters on the properties of this catalyst was examined and further correlated with CO production efficiency. The addition of EN changed the intensity ratio of (220) vs. (111) planes in the Ag catalyst, which was shown to be proportional to the CO production activity. Furthermore, EN modified the chemical shift of Ag3d5/2 in the negative direction, increasing the CO production efficiency. Under optimized deposition conditions (–0.45 V vs. Ag/AgCl, 40 mM EN), which were a compromise between intensity ratio and chemical shift, the fabricated Ag catalysts exhibited the highest Faradaic efficiency and mass activity for CO during CO2 electrolysis in 0.5 M KHCO3. The experimental correlation between CO production efficiency and the crystalline/electronic structures of the catalyst suggested guidelines for further improving the Ag catalyst activity.

We verified that a Cu seed layer could be damaged by a Pt insoluble anode in Cu electrodeposition. When the Cu seed layer was connected to the Pt galvanically, it was pitted and became resistive. The existence of Pt oxides on the Pt developed a potential with respect to the Cu seed layer, and accompanying electron flow from the Cu seed layer to the Pt insoluble anode. This resulted in the dissolution of the Cu seed layer, and the reduction of Pt oxides, which was confirmed by XPS analysis. The pitting current increased with the oxidation time and the surface area of the Pt, indicating the dissolution current on the Cu seed layer was associated with the Pt oxides on the Pt. This study implies that it is necessary to reduce the Pt anode regularly to prevent the Cu seed damage by the Pt anode in Cu electrodeposition.

본 연구에서는 구리 배선 공정에서 구리 씨앗층 표면에 형성되는 구리 자연산화물을 제거하는 표면 전처리가 후속 구리 전착에 미치는 영향을 살펴보았다. 구리 배선 공정의 화학적 기계적 연마 공정에서 사용하는 citric acid 기반의 용액을 구리 표면 전처리 과정에 적용하여 표면에 존재하는 구리 자연 산화물을 제거하...

The growth kinetics of copper microparticles was analysed by using the gravimetric method. The copper microparticles were synthesized in aqueous solution containing cupric ion and HCHO under various conditions (temperature, additive) and the total mass was monitored during the synthesis. The relation between the total mass and time was formularized using heterogeneous and pseudo-first order reaction kinetics of the autocatalytic surface growth of copper with a modification of the Finke–Watzky kinetic model. Fitting of theoretical curves to the experimental results with various temperatures provided the rate constants of the surface growth, and the reaction activation energy was found from the Arrhenius plot to be 105.4 kJ mol−1. The obtained value was validated by comparing it with one from copper film growth. Its change was observed with the addition of 2,2′-dipyridyl during synthesis.

Herein, bimetallic Ag/Cu nanowires (NWs) are prepared by electrochemical synthesis of Cu NWs and subsequent Ag galvanic displacement for the electrochemical reduction of CO2 to CO. The delicate execution of the displacement fabricates bimetallic NWs that possess controlled surface composition. The surface composition of NW is precisely controlled by varying the displacement time, and it is revealed by numerical and experimental methods that the catalytic activity is closely affected by the composition. The surface coverage of Ag measured based on under potential deposition according to the displacement time ranges from 70% to 94.3%. An increase in the Ag surface composition results in an improvement in the CO Faradaic efficiency from 29.8% to 39.6% and a significant increase in CO partial current density compared with Cu NWs and Ag foil. Namely, the catalytic activity of Ag/Cu NWs is dependent on the Ag coverage, and is governed by scaling relation.

A new concept of the desorbent swing adsorption (DSA) process operating at a constant pressure is proposed. The developed process was applied to the separation of propane and propylene because propylene, a high-demand chemical, is produced from an energy-intensive and expensive process. The selection criterion of desorbent was the chemical having the adsorption affinity between propane and propylene, and carbon dioxide was selected as a case study. According to the sequential breakthrough experiments, propylene was separated from propane in the CO2 pre-filled bed. However, the desorption step utilizing CO2 flow played a key factor in the separation performance because a faster desorbent flowrate enhanced the desorption of adsorbed propylene and prolonged the breakthrough times of the components. A two-bed DSA process (60% propane and 40% propylene), containing rinse-out and rinse-in steps, achieved 94.427% purity for propane with 99.655% recovery and 8.816 mol/(kg·hr) productivity, and 99.999% purity for propylene with 96.644% recovery and 5.700 mol/(kg·hr) productivity. Unusual temperature variances in the DSA process (decreasing during the adsorption step and increasing during the desorption step) was opposite to that in conventional adsorptive processes. These temperature variances contributed to an enhanced separation performance and process safety (prevention of zeolite 13X poisoning and gas fires). The feasibility of the DSA process was demonstrated without further requirements for additional energy arising from compression or a vacuum. The optimization of the DSA process and subsequent desorbent recovery processes is a subject for further studies.

In this study, we investigated the effect of reducing agents to decrease the chemical decomposition of SPS. We added reducing agents (hypophosphite, formaldehyde, glyoxylic acid, hydrazine, and oxalic acid) into the Cu plating bath and examined their effects on the voltammetric response, bath performance, and stability of SPS. Among these, hydrazine and oxalic acid resulted in the formation of precipitates, and thus could not be used for accurate analysis. Hypophosphite was electrochemically active in the cathodic region due to the reduction of metallic phosphite, which led to errors in the CVS analysis. Therefore, it was determined that only formaldehyde and glyoxylic acid could be used as reducing agents in Cu electrolytes. Formaldehyde reduced the rate of SPS decomposition more effectively. The bath performance with and without formaldehyde was evaluated by performing a via-fill test. Consequently, when formaldehyde was not present, SPS was rapidly decomposed by Cu+, and the filling performance became poor after aging for 3 h. However, when formaldehyde was present, the filling performance was maintained for up to 9 h and SPS decomposition in the open-circuit condition rarely occurred. These results indicate that formaldehyde reduces the number of active radicals, thereby reducing the chemical oxidation of SPS.

The importance of chemical mechanical planarization (CMP) and post-CMP cleaning is highly critical because both directly affect the yields and performance of semiconductor devices. Ceria nanoparticles are widely used as abrasives for SiO2 CMP because strong ceria–SiO2 interaction enhances CMP performance. However, the interaction is a major drawback in post-CMP cleaning processes where residual ceria nanoparticles must be completely removed from the SiO2 surface. The interaction depends on the cerium oxidation state of the ceria nanoparticles surface. In this study, the ceria–SiO2 interaction was investigated systemically using an atomic force microscope and a quartz crystal microbalance. The analysis revealed that the adhesion energy between ceria and SiO2 and the adsorption rate of ceria nanoparticles on a SiO2 surface increased with the surface concentration of Ce3+. This is direct evidence showing that the ceria–SiO2 interaction becomes stronger as the surface Ce3+ concentration of ceria nanoparticles increases, suggesting that the surface Ce3+ concentration should be reduced for effective post-CMP cleaning.

The effect of surface composition change based on complexing agents on cobalt (Co) post-chemical mechanical polishing cleaning (cleaning) is investigated. The change in chemical composition of the Co surface significantly affects Co cleaning performance, as well as dissolution capacity of the complexing agent and pH of cleaning solution. Oxide composition of the Co surface was manipulated using different types of complexing agents. Addition of citric acid and glycine in cleaning solution resulted in predominant formation of Co3O4 and CoOOH on the Co surface, respectively. The citric acid-derived Co3O4 surface embraces abundant –O– terminates, which attracts the complexing agent and silica abrasive relatively weakly, resulting in suppression of recess formation and reduction of surface particle residue after cleaning. On the contrary, the –OH terminated CoOOH surface formed by glycine bound strongly with silica. Therefore, preferential development of Co3O4 on the surface considerably enhances Co cleaning performance, which is achieved by introducing citric acid in the cleaning solution. To sum up, we suggested an unconventional insight to understand the effect of Co surface chemical state on cleaning performance.

A three–additive combination of an accelerator, a polymeric suppressor, and an organic leveler is typically utilized in the electrodeposition process to achieve Cu bottom–up filling of microvias on printed circuit boards. The use of several organic chemicals makes maintaining the performance of the electrolyte and additives more complicated due to the decomposition of the organic additives. As a replacement for the organic levelers, inorganic levelers, such as bromide ions, can avoid this problem since halide ions cannot produce organic by–products. This study investigates the effects of bromide ions on the adsorption of polymeric suppressors and accelerators and the influence of the concentration ratio of bromide ions and the accelerator on the bottom–up filling of microvias. The electrochemical analyses reveal that the bromide ions are adsorbed on the Cu surface and interact with the polymeric suppressor, increasing the suppression effect. In addition, bromide ions combined with the polymeric suppressor retard adsorption of the accelerator, and forced convection enhances the inhibitory effect of bromide ions. Electrochemical analyses also suggest that the accelerator to bromide ion concentration ratio is critical for controlling the surface activity for Cu electrodeposition and dictates the bottom–up filling characteristics. Microvia filling experiments indicate that in the optimum concentration ratio range (i.e., 0.2

A carbon fabric carrying a three-dimensional rigid structure and void spaces is utilized as a current collector for a copper-tin alloy (Cu 6 Sn 5 ) negative electrode in lithium-ion batteries. A core (carbon fabric)/shell (Cu 6 Sn 5 ) type electrode is prepared, without any passive component (conductive carbon and polymer binder) loading, by using electroless-plating method. The specific capacity of the resulting electrode, which is calculated on the basis of the total electrode weight, is 1.7 times larger than that obtained from the conventional-type electrode that is prepared by slurry coating of Cu 6 Sn 5 powder on a Cu foil along with the passive components. The higher specific capacity of the former is resulted from the lithium storage ability of the carbon fabric by itself and the absence of passive components. The other beneficial feature offered by the carbon fabric current collector is negligible electrode swelling, which is possible because the spacious voids in the carbon fabric can accommodate the volume expansion of Cu 6 Sn 5 component.

The microstructural changes in electrodeposited Cu films during self-annealing is demonstrated in this study. The structural change is strongly influenced by the organic additives in the Cu electrodeposition. The use of either polyethylene glycol (PEG) or bis-(3-sulfopropyl) disulfide (SPS) decreases the Cu(111) grain size of deposited films, as the adsorption of the additives suppresses the surface diffusion of the Cu ions during the electrodeposition. After the electrodeposition, the average grain size of the deposited film was simultaneously increased by 10% in a self-annealing process to reduce the defect energy, which is mainly composed of the surface energy of the grains. Meanwhile, the grain grew 4 times larger than the as-deposited grain size during the self-annealing when both the PEG and SPS were introduced. The drastic grain growth was attributed to the accumulation of a high defect energy in the deposited film. The dynamic interaction between the co-adsorbed PEG and SPS on the Cu surface during the electrodeposition promotes an unoriented dispersion-type deposition, resulting in high-strain energy as well as surface energy. Releasing the strain energy accumulated by the high density of misorientation also leads to the simultaneous growth of Cu(200) grains.

In an attempt to ameliorate the poor cyclability of LiNi0.5Mn1.5O4 at elevated temperature, quercetin is applied as an additive. The irreversible oxidative behavior of quercetin is thoroughly investigated by electrochemical method. The improved cyclability of the quercetin-containing cell at high temperature implies that by forming robust and less-resistive SEI, quercetin is preferentially oxidized and passivates the LiNi0.5Mn1.5O4 electrode. EIS result coherently suggests that the quercetin-added electrolyte forms a more compact and Li-ion conducting interface. The surface sensitive XPS analysis confirms that the presence of quercetin restrains the formation of LiF, suppresses the reaction of PF5, and alleviates Mn dissolution. Meanwhile, ICP-MS analysis affirms the effectiveness of quercetin against Mn dissolution. The self-discharge experiment which exhibits the retained charged state of LiNi0.5Mn1.5O4 at high temperature, gives convincing evidence of the effect of quercetin. Intensive analyses confirm that quercetin can effectively prolong the cycle-life of LiNi0.5Mn1.5O4 at elevated temperature. We envision its potential and practical usage as an electrolyte additive for high-voltage cathode.