Selective Electroless Copper Plating of Ink-Jet Printed Textiles Using a Copper-Silver Nanoparticle Catalyst

The copper-coated polyester fabric can be used to prepare electromagnetic shielding materials. At present, electroless copper plating mainly using formaldehyde as the reducing agent. But the stability of the bath is poor and it is also volatile and toxic. Using hypophosphite as reducing agent has more advantages for its stability and the plating process does not release any toxic gases. In this paper, The copper-coated polyester fabric was prepared by electroless plating with the sodium hypophosphite as reducing agent. The roughening condition before plating and the deposition process were optimized through orthogonal test. The surface resistances of conductive polyester fabrics, the deposition rate and the coating adhesion were investigated respectively. The optimum roughening conditions obtained are as following: sodium hydroxide concentration of 250g/L; temperature 70 D; time 15min, and the lightweight rate of the plating layer is 0.43% under the experimental conditions. The optimum conditions of electroless copper plating using sodium hypophosphite as reducing agent are: copper sulfate 8g/L; nickel sulfate 1.0g/L; sodium hypophosphite 35g/L; citric acid 20g/L; boric acid 30g/L; pH 9.0; temperature 75D. With these conditions, the deposition rate reaches 1.274g/(m2·min) and the uniform and compact copper layer with excellent electro-conductivity was obtained.

Advanced Ag nanoparticles for the catalyzation of glyoxylic acid oxidation in through-holes electroless copper metallization

A new activation process for electroless copper plating has been developed, which does not require the use of a palladium-based activation bath as typically employed in the plating industry. The activation bath of the new process described herein is entirely free of palladium and is based on colloidal metallic copper particles, which are nanoscopic in size. This bath can also be readily analysed and controlled. The new copper-based activation bath can be operated in such a way that colloid agglomeration and colloid oxidation are efficiently and effectively suppressed, while electroless copper plating quality and electroless copper bath stability is maintained. In addition, the new activation bath can be operated for several weeks without any detectable deterioration in electroless copper plating performance. Furthermore, acrylonitrile butadiene styrene (ABS) and FR4 coupons treated with the new copper-based colloidal activation bath can be vigorously rinsed with water for several minutes prior to immersion in the electroless copper bath without loss of plating quality. The new activation process performs comparably to an established palladium-based process operated at typical vertical equipment immersion times. Even though the electroless copper plating initiation is somewhat delayed for the new copper-based activation process, the final electroless copper deposit thicknesses are the same for both the new process and the palladium-based reference process. The adhesion of the electroless copper deposit obtained with the copper-based activation process is also similar to that obtained with the palladium-based reference activation system. Moreover, the electroless copper coverage performance of the new copper-based activation process, as determined by the backlight test, is comparable to that of the palladium-based reference process.

Surface modification is an effective method to improve the electrochemical property of hydrogen storage alloy. In order to investigate the influence of process factors of electroless copper (Cu) plating for AB5-type hydrogen storage alloy on Cu coating mass, a novel modeling approach, support vector regression (SVR) combined with particle swarm optimization (PSO), was proposed to construct a mathematical model for prediction of the mass changes of Cu coating over the AB5 hydrogen storage alloy surface based on three factors, including temperature, pH value and Ni2+ concentration. The modeling accuracy and reliability of the created SVR model are validated through leave-one-out cross validation (LOOCV), and compared with those of a second-order polynomial model. The results show that the predicted errors by SVR-LOOCV models are all smaller than those achieved by the second-order polynomial model. The SVR model is further applied to predict the process parameters for the maximum Cu coating mass. These studies suggest that SVR can be used as an effective methodology to assist the design of experiment, and is helpful to precisely control the coating mass via fine adjustment of the process parameters. Key words: Surface modification, electroless copper plating, hydrogen storage alloy, support vector regression, modeling and prediction.

Electroless copper plating has attracted more and more interests as an effective process for metalizing ceramic surface. Direct plated copper (DPC) ceramic spreader has been widely used for high-power LED packing. Usually, preparation of DPC used sputtering Ti/Cu for seed layer following by thick copper plating. In this work, DPC fabrication was optimized by applying the electroless plating copper as seed layer. The orthogonal experiment, single-factor analysis and other methods were used to optimize the electroless copper plating process, and the coating properties were evaluated by tensile test, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS).

Selective electroless copper plating micro-coil assisted by 248 nm excimer laser

Although electroless copper deposition has been widely used in the electronic industry, the selection of the bath solutions relies still on some empirical rules. This paper provides a further exploration of the bath compositions for electroless copper plating. It was found that the formation of Cu2O in electroless copper plating is associated with the presence of Cu(OH)2 in the bath. A chemical equilibrium calculation was thus made for the avoidance of Cu(OH)2 in an electroless copper bath. Sodium thiosulfate was found to be an effective stabilizer for electroless copper plating. The plating was further optimized based on a statistical design of sorts, namely, Taguchi's approach. Effects of individual components on the plating rate were discussed.

Effects of simplified pretreatment process on the morphology of W–Cu composite powder prepared by electroless plating and its sintering characterization

The present work is focused on electroless coating of copper nanolayer onto boron carbide (B4C) particle surfaces by using copper activation method. The B4C particles used are approximately 18.25μm in average size. B4C particle surfaces were washed by acetone and activated through copper activation method. In the electroless coating bath, copper sulfate, EDTA-2Na and seignette salt, hydrazine hydrate were used as the copper catalytic centers source, complexing agent and reducing agent respectively. The structure and morphology of the coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD and SEM observations show that B4C particle surfaces were successfully coated by a homogeneous and continuous copper layer.

An optimization analysis on electroless deposition of Al2O3/Cu core-shell nanostructures

A detailed study was undertaken on one practical system used in electroless plating of ABS plastics. The macroscopic appearances were examined after short and standard etch times, after catalytic and accelerating steps as well as after electroless copper and nickel plating steps. X-ray Photoelectron Spectroscopy was used to examine the chemical status of the surface during different plating steps and Transmission Electron Microscopy was used to analyze polymer-metal interface dependence on etching conditions

Electroless copper plating is a vital technique for depositing uniform and conductive copper layers, particularly for fabricating copper-coated polymer microspheres used in anisotropic conductive adhesives. However, achieving high-quality coatings on polymer microspheres remains challenging due to their inherent catalytic inertness and the lack of reliable evaluation metrics. Herein, copper nanoparticles are utilized as catalytic seeds for electroless copper plating on styrene-divinylbenzene (PSDVB) microspheres via a prereduction step using ammonia borane. After tailoring the bath composition and processing conditions, the optimized PSDVB@Cu microspheres with a dense 0.047 μm thick copper layer, 50.60 wt % copper content, and a low resistivity of 6.04 × 10-6 Ω·m can be obtained. Crucially, two novel quantitative indicators, named oxidation degree and densification degree, are introduced to comprehensively assess coating quality. A clear correlation is established among the densification degree, oxidation degree, and electrical performance. Specifically, the microspheres become conductive only when the densification degree exceeds 0.2 and the oxidation degree falls below 3.0. With a densification degree above 0.4 and an oxidation degree below 1.4, the resistivity stabilizes near 10-6 Ω·m. Beyond elucidating a tunable electroless copper plating process, this work provides a quantitative framework for coating assessment, paving the way for the standardized fabrication of high-performance copper-coated microspheres in advanced electronics.

A facile process to fabricate metal coating on PET sheet: Preparation of highly active polymer brush/Ag particle and its application in electroless copper plating

Hydrolysis modification of nitrile groups on acrylonitrile butadiene styrene (ABS) plate surfaces into carboxylic acid groups was investigated to find a new recipe for electroless copper plating of ABS plate surfaces without etching reactions using chromic acid and also without a palladium catalyst. Hydrolysis modification of nitrile groups was successfully conducted in an aqueous sodium hydroxide (NaOH) solution (70 wt %) at 80°C for more than 72 h, and nitrile groups were modified into carboxylic acid groups. The hydrolysis modification was accelerated by the addition of dioxane as a supplement to the aqueous NaOH solution. The modification, when an aqueous mixture solution of NaOH (35 wt %) and dioxane (10 wt %) was used as a reagent, was accomplished at 65°C in 30 min. The hydrolyzed ABS plate surfaces were successfully metalized by electroless copper plating. A silver catalyst, instead of a palladium catalyst, was usable in the electroless copper‐plating process. Adhesion between the deposited copper metal and ABS plate surface was perfect for the Scotch tape test. Consequently, we propose a new recipe for an electroless copper‐plating process without an etching process using chromic acid and without a palladium catalyst. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The metallization of low temperature co-fired ceramic (LTCC) is typically done with commercially available silver or gold pastes using conventional screen printing processes. However, for some applications such as substrate integrated waveguides and high performance planar components where the metallization of vertical side walls is required, screen printing is difficult to apply. In such cases, electroless plating of copper can be employed to metallize the fired LTCC, which would also be a promising alternative to the high cost metals such as Ag and Au. In this study, electroless copper plating was combined with KrF excimer laser machining to deposit selective copper patterns on fired LTCC. Using this approach, a functional circuit was fabricated and electrically tested. The mask projection technique of the excimer laser can be used to create complex patterns on LTCC and initial work has been carried out to realize planar passive component layouts, including a capacitor and an inductor. The minimum feature size of the deposited copper that could be achieved in these designs was below 50 μm.