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Electrodeposition-based metal coating techniques are used to manufacture various industrial products and rely on the quantitative control of the physical properties of the coating layers, such as electrical conductivity, surface roughness, and hardness. To clarify the experimental conditions required to realize the desired physical properties of metal coating layers and shed light on the complex mechanism of the involved reactions, we prepared a custom-built experimental dataset (60 conditions) on the surface roughness of electrodeposited thin copper films and submitted it to an open-access data repository. Data-driven analysis revealed that surface roughness is strongly affected by the deposition temperature, current, and interelectrode distance.

High power impulse magnetron sputtering (HiPIMS) parameters such as the frequency, duration and amplitude of the discharge current pulses can be adjusted over a wide range to change the energy conditions for coating formation. This in turn leads to changes in the structure and properties of the deposited coatings. Measurement of the energy flux onto the substrate during high power pulse magnetron sputtering of copper is the subject of this paper. It is shown that for a fixed peak discharge current and average discharge power, a significant increase in the energy transferred to the coating can be achieved by reducing the duration of the current pulses. In this case, both the total energy flux onto the substrate and the normalized energy transferred per unit volume of the coating will be increased. The reasons for the increase in energy are examined in the paper. The ability to control the energy transferred to the coating by adjusting the HiPIMS pulse parameters is demonstrated. [ABSTRACT FROM AUTHOR]

Abstarct: With the increase of the density of interconnecting technology for chip packaging, it is required to form smaller vertical interconnect micro-via in insulating dielectric materials with advanced packaging technology. However, a continuous and uniform copper film cannot be formed on the sidewall of the micro-via after plasma etching due to the existence of the undercut at the top of the micro-via. This paper has developed an interconnecting process for depositing copper film in 5–10 μm polyimide micro-via based on DC magnetron sputtering technology and investigated the effect of sputtering process parameters on the uniformity of copper film deposited in micro-via. It is found that sputtering power, bias voltage and working pressure have a great influence on the uniformity of the deposited copper film at the sidewall of the micro-via, and these parameters will lead to the deposition gap. In contrast, the rotating speed and deposition time have little influence on the uniformity of copper film deposited on the micro-via, and there is no undeposited phenomenon on the side wall of the micro-via. When sputtering power is 50 W, bias voltage is −70 V, working pressure is 4 mtorr, rotating speed is 10 rpm, and deposition time 5000 s, the wall, bottom and top of the micro-via are covered by continuous copper film, and the copper film on the sidewall is continuous and homogeneous. The optimised process parameters can be sputtered in the micro-via with a diameter of 5–10 μm.

The main cause of the surface wear of box-like parts of bearing interfaces is determined. According to the test results, an engineering solution for fretting corrosion control is proposed which consists in the friction application of copper films on the surface in contact with the bearing. [ABSTRACT FROM AUTHOR]

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For copper (Cu) interconnection chemical mechanical polishing (CMP) process, the Cu film slurry follows the principles of high efficiency, environmentally friendly and low cost. In this study, hydroxyethylene diphosphonic acid (HEDP), amino-trimethylene phosphonic acid (ATMP) and ethylenediamine etramethylenephosphonic acid (EDTMP) were used as green inhibitors to study the effects of organic compounds rich in two, three and four phosphate functional groups on the corrosion inhibition properties of Cu films. The results indicated that the Cu film material removal rate (MRR) of HEDP reaches 5879 A/min and the surface roughness (Sq) is 0.85 nm, superior to the other two inhibitors. Through mechanical action analysis, electrochemical experiment, UV-Visible, X-ray photoelectron spectroscopy (XPS) test analysis and theoretical calculation, it was observed that three inhibitors could not only form stable complexes with Cu, which have the effect of corrosion inhibition, but also play a lubricating role of surfactant, and simplify the composition of slurry, and the inhibition efficiency order of them is HEDP > ATMP > EDTMP. [Display omitted] ● The Cu film MRR of HEDP reaches 5879 A/min and the surface roughness (Sq) of Cu films treated with HEDP is 0.85 nm. ● Three inhibitors can reduce coefficient of friction (COF), improve the lubricity, and play the role of surfactant. ● The oxygen atoms on the phosphate functional groups in HEDP have higher molecular activity than in ATMP and EDTMP. ● The composition of slurry is simplified and the industrial cost is reduced. [ABSTRACT FROM AUTHOR]

Due to the exceptional electrical properties, graphene (Gr) has shown remarkable potential in reducing the resistivity of Cu. However, the systematic studies on the influence of Gr on microstructure and electrical properties of Cu thin films are rare, which is particularly important for the application of Cu interconnection in integrated circuits. In this study, we investigated the growth characteristics and electrical performance of Cu films with consideration of Gr-Cu interactions. In contrast to the anticipated 20 % reduction in electrical resistivity for Gr/Cu/SiO 2 /Si, the Cu/Gr/SiO 2 /Si unexpectedly demonstrates a 1018 % increase in electrical resistivity compared to Cu/SiO 2 /Si counterpart at 7 nm thickness. Our results suggested that the increased surface roughness induced by the weak interaction of Gr-Cu exacerbated the surface electron scattering, offsetting the advantages offered by the additional carrier transport channel provided by Gr. This finding underscores potential limitations in the application of Gr in micro-electronics interconnection. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, micro-scribing of Cu film on a dielectric substrate with lasers having different pulse duration (6 ns, 500 ps, 1 ps, 120 fs) has been analyzed. The recast layer formation near the microchannel is clearly observed in the case of 6 ns and 500 ps laser-based scribing. On the other hand, 1 ps and 120 fs pulsed lasers were able to produce microchannel without observable recast layer. Based on the XRD analysis, compressive residual stresses are observed in the scribed region with the 6 ns and the 500 ps laser, whereas tensile residual stresses are measured in the scribed region with the 1 ps and the 120 fs lasers. Oxide layer formation was observed in the case of all the pule regimes. A theoretical simulation was developed to estimate the temperature on the dielectric substrate. Complete removal of Cu from the dielectric will resulted in thermal damage to the substrate. A hybrid micro-scribing technique, where the sample was immersed in NaCl solution during the final laser scan was demonstrated in the case of nanosecond laser. Finally, a frequency selective surface (FSS) was fabricated with the help of the hybrid scribing technique. [ABSTRACT FROM AUTHOR]

The influence of different anode configurations on the growth mechanisms, transient currentsand surface morphologies of copper film using localized electrodeposition technique have been studied. Measured transient currents during electrodeposition wereused to investigate the underlying growth dynamics. SEM images were obtained and the surface morphologies of the deposited copper films were analyzed. It was found that the transient current increased when copper ions were able to grow directly on the empty surface of the copper film that was located away from the mini electrodes. This caused the copper ions to be deposited sporadically via the instantaneous growth mechanism and formed cluster of atoms on the empty surface of the copper film which led to rougher surfaces. In contrast, progressive growth was observed to occur at a faster rate for the deposition performed using insulated mini electrodes, especially in the case of collinear double insulated mini electrodes as indicated by the reduction of the transientcurrent with time. Besides, copper films with uniform and smoother surfaces were obtained when the depositions were performed using multiple or a large number of closely spaced mini electrodes. This was due to the fact that large number of closely spaced mini electrodes produced parallel and uniform electric field patterns.

A single-layer film of copper and/or copper oxide was deposited on a polypropylene nonwoven fabric substrate to prepare multifunctional textiles with a metallic color appearance. The pristine uncoated nonwoven fabric was gray, the copper film-coated fabric was orange-red, and the copper oxide film-coated fabrics were dark red and dark green. With the increase of flowing oxygen, the Cu content of the film decreased and changed into Cu2O, after which it gradually changed to CuO. The color lightened as the color brightness increased, while the K/S value decreased as the CuO content increased. The hydrophobicity of the copper oxide film-coated samples slightly increased while the ultraviolet (UV) protection performance (UPF) was overall reduced as the oxygen flowing rate increased and the film thickness decreased. The copper film-coated sample exhibited momentary electrostatic attenuation, but the electrostatic elimination ability of the copper oxide film-coated samples decreased owing to the conversion of elemental Cu to Cu2O and then CuO. [ABSTRACT FROM AUTHOR]

In this research, the pump-probe imaging technology and the time-resolved transmittance measurements are used to investigate the transient time scale of the oxidation area, the dewetted melt pool, and the ablation-induced mass transport, and their dependence on the incident laser. Moreover, the evolution time of various morphologies have been studied through a certain delay time from 10 to 30 ns with different dynamic processes. Meanwhile, the underlying formation mechanism and the phase change pathway have been studied. In this regard, a nanosecond (ns) pulsed laser with 532 nm wavelength was used to fabricate nanostructures on the surface of the thin Copper (Cu) films. The observations confirmed that the oxidation process of Cu plays a significant role in the mechanism of laser fluence-dependent oxidation, melting, and ablation dynamics. The results revealed that the different characteristics of the Cu film are related to the incident laser pulse energy. Furthermore, the experimental evidence was in good agreement with the SEM images and the Raman spectra. It is found that the Cu2O surface-rim with a central hole could be fabricated with the laser fluences above the ablation threshold. Although, for the laser fluences below the ablation threshold, the Cu2O phase can be formed in the central region.

The growth of high-quality graphene on flat and rigid templates, such as metal thin films on insulating wafers, is regarded as a key enabler for technologies based on 2D materials. In this work, the growth of decoupled graphene is introduced via non-reducing low-pressure chemical vapor deposition (LPCVD) on crystalline Cu(111) films deposited on sapphire. The resulting film is atomically flat, with no detectable cracks or ripples, and lies atop of a thin Cu 2 O layer, as confirmed by microscopy, diffraction, and spectroscopy analyses. Post-growth treatment of the partially decoupled graphene enables full and uniform oxidation of the interface, greatly simplifying subsequent transfer processes, particularly dry-pick up - a task that proves challenging when dealing with graphene directly synthesized on metallic Cu(111). Electrical transport measurements reveal high carrier mobility at room temperature, exceeding 10 4  cm 2  V -1  s -1 on SiO 2 /Si and 10 5  cm 2  V -1  s -1 upon encapsulation in hexagonal boron nitride (hBN). The demonstrated growth approach yields exceptional material quality, in line with micro-mechanically exfoliated graphene flakes, and thus paves the way toward large-scale production of pristine graphene suitable for high-performance next-generation applications., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

[Display omitted] • Combination of experiments and DFT calculations. • Triazole derivatives are eco-friendly and sustainable inhibitors for metal. • Effect of various derivative groups on inhibition efficiency. • Multi-angle study of molecular activity and adsorption behavior on Cu surface. • Provide reference for the selection of organic inhibitors for multiple metals. The impact of triazole derivative groups on corrosion inhibition performance of copper (Cu) film is studied by using 3-amino-1,2,4-triazole-5-carboxylicacid (ATA-O), 1H-1,2,4-triazole-3,5-diamine (ATA-N) and 3-amino-5-mercapto-1,2,4-triazole (ATA-S) as environment-friendly inhibitors. Electrochemical analysis showed that anti-corrosion passivation layer is formed on Cu surface after adding inhibitors with high inhibition efficiency of 54 %, 87 % and 98 % respectively, and improve the surface quality which is verified by atomic force microscope (AFM) and scanning electron microscopy (SEM) tests. Such results are consisted with static etch experiments. The mechanism of corrosion inhibition was revealed by theoretical calculation, which prove that the lone electron pair in empty orbitals of the O, N, S atoms on inhibitors hybridize with the Cu-d orbital to form covalent bonds and enhance the adsorption passivation action. Such study dissects the reasons for the potent inhibitory effect of triazole derivatives at the atomic level, and provides new method for efficient selection of inhibitors. [ABSTRACT FROM AUTHOR]

We directly synthesized multi-layer graphene with an area of several hundred square microns on the lithium niobate (LN, LiNbO _3 ) substrate by Carbon (C) implantation into the copper (Cu)-covered LiNbO _3 . The energy of C ion implantation was optimized per SRIM simulation to ensure that the distribution of C covers the Cu/LiNbO _3 interface. The optimized energy was established at 55 keV, such that the formation of C peaks in the respective materials on each side of the Cu/LiNbO _3 interface. The diffusion of the accumulated C to the Cu/LiNbO _3 interface can form a more uniform C distribution at the interface, which is beneficial to the synthesis of graphene. Following the annealing process and removal of the Cu coating, a multi-layer graphene with an area of several hundred square microns on the surface of LiNbO _3 was identified and characterized using Scanning Electron Microscopy (SEM), Energy-Dispersive x-ray Spectroscopy (EDS), Raman spectroscopy, and Atomic Force Microscopy (AFM). This remarkable advancement encourages the industrialization of direct graphene synthesis on LiNbO _3 substrates via ion implantation.

Abstract We present investigations of the energy flux in DC magnetron sputtering for 15 different target-gas combinations. The utilized gases were Ar, Kr and He which were studied using targets made of Ag, Al, Cu, Ti and W. The effect of parameter variations (distance, pressure and discharge power) was investigated by calorimetric measurements utilizing a passive thermal probe. For the variation of discharge power, supplementary measurements of plasma parameters and deposition rate were performed using a planar Langmuir probe and a quartz crystal microbalance. The obtained results were used to gain better insight into the different contributions to the integral energy flux. The measurements illustrate clearly that, depending on the target material and on the target gas combination, the main mechanisms generating the energy flux can vary dramatically. For small gas-target mass ratios, reflected neutrals were identified as the main contribution of the energy flux while for combinations with high sputter yield, condensation and kinetic impact of sputtered particles were found to be the most relevant. For thermally poor conducting targets as in the case of titanium, the target can heat up significantly resulting in a strong energy flux from heat radiation which dominates the otherwise modest energy flux. Highlights • Energy flux for 15 gas-target combinations • Results for variation of magnetron power, substrate distance and gas pressure • Contributions to the integral energy flux from QCM, Langmuir probe, and SRIM • Identification of the main driving mechanisms for integral energy flux • Sputtered atoms, reflected neutrals, target heat radiation contribution are the main parameters [ABSTRACT FROM AUTHOR]

In laser cladding, in the wavelength range of blue, light absorptivity of copper is much higher than that in the wavelength range of infrared. The authors developed the laser cladding system with the continuous wave blue direct diode laser (blue DDL). The system consists of a number of fiber-coupled blue DDLs with a maximum power of 20 W at a wavelength of 445 nm, a focusing lens, and a powder feeding nozzle. In this study, the authors investigated the fundamental characteristics of the multiple blue DDL system and formed copper film on 304 stainless steel plate using the system. [ABSTRACT FROM AUTHOR]

In this work, we studied the effect of inert ion implantation using helium and xenon ions on residual stress gradients in copper films. A copper microcantilever beam array was fabricated on a (1 0 0) silicon wafer by conventional bulk micromachining. The as-fabricated copper microcantilevers showed upward bending deformation as a result of positive residual stress gradient in films. Helium and xenon ions were implanted at various doses and energies into microcantilevers before releasing them from substrates. The magnitudes and signs of residual stress gradients were effectively controlled by both helium and xenon ion implantation and depended on implantation energy and ionic dosages. The mechanism of residual stress control appeared to involve counterbalancing residual stress gradients with compressive residual stresses induced by volume expansions of implanted regions and the direct effect of surface modification by ion bombardment. [ABSTRACT FROM AUTHOR]

Thin Pd coatings were obtained on glassy carbon electrodes by galvanically replacing the electron beam-deposited copper layers with palladium. The prepared electrodes were studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The electrodes were electrochemically tested for oxygen reduction reaction (ORR) employing the rotating disc electrode (RDE) method in alkaline solution. The remaining copper was detected for two of the thickest (5 and 10 nm) sacrificial Cu layers using energy-dispersive X-ray spectroscopy (EDX). SEM images of thin Pd films showed some larger particle growth for all the studied film thicknesses, but spherical particles such as those achieved for example by the electron beam evaporation method were not visible. Specific activity of the electrodes for O2 reduction did not depend on the thickness of the sacrificial copper layer. The O2 reduction reaction followed a four-electron pathway with a mechanism similar to that of commercial Pd/C, where the first electron transfer to the O2 molecule is the rate-determining step.ᅟ [ABSTRACT FROM AUTHOR]

Magnetoelectrolysis (electrolysis under magnetic fields) produces chiral surfaces on metal thin films, which can recognize the enantiomers of amino acids. Here, the chiral surface formation on copper films is reported in magnetoelectrochemical etching (MEE) at 5T with chloride additives. In the absence of additives, the surface chirality signs of MEE films depended on the magnetic field polarity. On the contrary, the MEE films prepared with the additives exhibited only D-activity in both magnetic field polarities. This result implies that the specific adsorption of chloride additives induces the chiral symmetry breaking for the magnetic field polarity. [ABSTRACT FROM AUTHOR]

The cyclic stress–strain constitutive relationships for copper film smooth specimens with different damage degrees before and after laser irradiation treatment were investigated. Compared with the changes of the constitutive relationships under different damage degrees, a healing variable for the repaired copper film by laser irradiation was defined. Based on the analysis of the healing variable, a fatigue life prediction method was proposed. The experimental lives of the damaged notched specimens after laser irradiation treatment were used to verify the proposed life prediction method. The results showed that the predicted lives are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

The results of experiments on the synthesis of micro- and nano-diamonds by an oxy-acetylene torch on the surface of the pre-deposited copper thin films are presented in this article. The influence of thickness of a buffer copper film and the ratio of the concentrations of oxygen and acetylene on the structure of the deposited samples has been studied in the course of the conducted experiments. The studies by Raman scattering and scanning electron microscopy showed that the synthesis of micro- and nano-diamonds occurs under certain experimental conditions. From the results of the analysis of the obtained samples by the methods of Raman scattering and scanning electron microscopy, it was determined that the deposition time of the copper films and consequently its thickness mainly influence on the structure formation of diamond crystals. On copper films grown for 30 min, the Raman scattering method showed a shift of the diamond peak from the standard (1332 cm‒1) to the low-frequency band (1331.3 cm‒1), which may occur after the presence of stress in the crystals. The results of the investigation showed that with increasing of synthesis time take place smoothing of the facets of crystallites (scanning electron microscopy) and decrease in intensity of the diamond peaks (Raman scattering method). [ABSTRACT FROM AUTHOR]

Metallization of carbon fiber reinforced plastic (CFRP) materials is a critical issue for protection against environmental attack and improvement of their electrical conductivity. In practice, the process should be preferably carried out below 150 °C to avoid epoxy resin decomposition. This work investigated a plasma enhanced pulse chemical vapor deposition process for copper thin film deposition at a temperature as low as 50 °C. Copper(I) di-isopropylacetamidinate was used as Cu precursor with high reactivity to H 2 plasma at low temperature. At certain experimental conditions (10 s Cu precursor pulse and 10 s H 2 plasma pulse, 100 °C), the Cu films deposited on CFRP were pure, continuous, with the resistivity of 4.4 μΩ cm. The influence of the deposition temperature on copper characteristics has been investigated. [ABSTRACT FROM AUTHOR]

The low energy argon ion is used for irradiation polycarbonate samples using cold cathode ion source. The surface of the PC substrates is examined using SEM, UV-spectroscopy and FTIR. It was found that the energy band gap decrease by increase argon ion fluence. Copper films are deposited onto polycarbonate (PC) substrates after irradiation by argon ion beam. The structure, surface morphology and the optical band gap are investigated using XRD, SEM and UV spectroscopy. It can be seen that the intensity increases with deposition time and band gap decreases from 3.45 eV for the pristine PC to ∼1.7 eV for copper thin film. [ABSTRACT FROM AUTHOR]