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This paper discusses how the grain size of plated copper changes as time passes by observing the copper surface topography after surface treatment with a roughening agent. This paper also discusses how the time until the recrystallization terminates depends on the amount and type of plating additives as well as current density. The results agree with the known mechanism of grain growth. As a result of our experiments, the best process to gain the optimal surface topography is proposed. We firmly believe that this paper will contribute to the improvement in quality control of the copper surface treatment process, which will in turn lead to the fabrication of PCBs and plastic packages with higher reliability.

The purpose of this paper is to introduce a new copper electroplating formula which is able to fill blind microvias (BVHs) and through holes (THs) at one process through a direct current (DC) plating method.

Test boards of printed circuit board (PCB) fragments with BVHs and THs for filling plating are designed. The filling plating is conducted in a DC plating device, and the filling processes and influence factors on filling effect of BVHs and THs are investigated. Dimple depths, surface copper thickness, thermal shock and thermal cycle test are applied to characterize filling effect and reliability. In addition, to overcome thickness, increase of copper on board surface during filling plating of BVHs and THs, a simple process called pattern plating, is put forwarded; a four-layered PCB with surface copper thickness less than 12 μm is successfully produced.

The filling plating with the new copper electroplating formula is potential to replace the conventional filling process of BVHs and THs of PCB and, most importantly, the problem of thickness increase of copper on board surface after filling process is overcome if a pattern plating process is applied.

The dimple depth of BVHs and THs after filling plating is not small enough, though it meets the requirements, and the smallest diameter and largest depth of holes studied are 75 and 200 μm, respectively. Hence, the possibility for filling holes of much more small in diameter and large in depth with the plating formula should be further studied.

The paper introduces a new copper electroplating formula which achieves BVHs and THs filling at one process through a DC plating method. It overall reduces production processes and improved reliability of products resulting in production cost saving and production efficiency improvement.

Optimized plating conditions, included proper designs of insulating shield (IS), auxiliary cathode (AC) and different patterns, contribute to the uniformity enhancement of copper deposition.

Plating experiments were implemented in vertical continuous plating (VCP) line for manufacturing in different conditions. Multiphysics coupling simulation was brought to investigate and predict the plating uniformity improvement of copper pattern. In addition, the numerical model was based on VCP to approach the practical application.

With disproportionate current distribution, different plating pattern design formed diverse copper thickness distribution (CTD). IS and AC improved plating uniformity of copper pattern because of current redistribution. Moreover, optimized plating condition for effectively depositing more uniformed plating copper layer in varied pattern designs were derived by simulation and verified by plating experiment.

The comparison between experiment and simulation revealed that multiphysics coupling is an efficient, reliable and of course environment-friendly tool to perform research on the uniformity of pattern plating in manufacturing.

The adhesion between electroless copper and a substrate is one of the most important factors in the reliability of thermoplastic printed circuit boards. The purpose of this paper is to investigate the effects of mechanical grinding and acid etching of thermoplastic substrate materials on the adhesion of copper deposited by an electroless copper plating process. The base material of the test substrates was a new high temperature thermoplastic polyphenylene oxide (PPO) compound.

The effects of pre‐treatment on plastic surfaces are analyzed by the following methods: Fourier transform infrared (FTIR), SEM, the Dyne surface energy test and the surface roughness test. The adhesion between electroless copper and thermoplastic substrate is measured with a peel strength test.

The results showed that mechanical grinding of the substrates significantly increased adhesion but the highest adhesion is gained by using an acid etch treatment before electroless plating. These results indicated that adhesion between copper and the substrates was not directly proportional to the roughness and surface energy values.

The conventional sweller/desmear treatment used in a printed circuit board factory for pre‐treating epoxy based laminates prior to electroless plating is not suitable for these PPO compound boards. The copper adhesion is adequate when the substrates are etched with sulphuric acid/chromate solution. In that case the bonding between the metal layer and the plastic surface is stronger than the bondings between the polymer chains of the thermoplastic material. The adhesion mechanism of electroless copper in these mechanically abraded samples is mechanical interlocking of metal particles.

The purpose of this paper is to investigate if copper nanoparticles could be utilized for two types of through hole plating in printed circuit boards, namely: as a catalytic material to initiate the electroless copper deposition process; and as a “conductive” layer which is coherent and conductive enough to allow “direct” electroplating of the through hole. The employment of nanoparticles means that an effective method of dispersion is required and this paper studies the use of mechanical agitation and ultrasound for this purpose.

The paper utilized drilled, copper clad FR4 laminate. The through holes were functionalized using a commercially available “conditioner” before being immersed in a solution of copper nanoparticles which were dispersed using either a magnetic stirrer or ultrasound (40 kHz). When the copper nanoparticles were utilized as a catalytic material for electroless copper plating, the efficacy of the technique was assessed using a standard “backlight” test which allowed the plating coverage of the through holes to be determined. As a control, a standard palladium catalysed electroless copper process was employed. The morphology of the electroless copper deposits was also analysed using scanning electron microscopy. In the “direct plate” approach, after immersion in the copper nanoparticle dispersion, the through holes were electroplated at 3 Adm⁻² for 15 min, sectioned and examined using an optical microscope. The distance that the copper electroplate had penetrated down the through hole was then determined.

The paper has shown that copper nanoparticles can be used as a catalytic material for electroless copper plating. The coverage of the electroless copper in the through hole improves as the copper nanoparticle concentration increases and, at the highest copper nanoparticle concentrations employed, good, but not complete, electroless copper coverage is obtained. Dispersion of the copper nanoparticles using ultrasound is critical to the process. Ultrasonically dispersed copper nanoparticles achieve some limited success as a conductive layer for “direct” electroplating with some penetration of the electroplated deposit into the through hole. However, if mechanical agitation is employed to mix the nanoparticles, no through hole plating obtaines.

The paper has demonstrated the “proof of concept” that copper nanoparticles can be utilized to catalyse the electroless copper process, as well as their potential to replace costly palladium‐based activators. The paper also illustrates the potential for copper nanoparticles to be used as a “direct plate process” and the necessity for using ultrasound for their dispersion in either process.

The adsorption and acceleration behavior of 3-mercaptopropyl sulfonate (MPS) were investigated by electrochemical tests for microvia filling by copper electroplating.

The synergistic effects of one suppressor of propylene oxide ethylene oxide propylene oxide named PEP and MPS as the accelerator during copper electroplating were also investigated by electrochemical methods such as electrochemical impedance spectroscopy cyclic voltammetric stripping (CVS) and Galvanostatic measurements (GMs).

The research results suggest that the adsorption of MPS onto the Cu-RDE metal surface was a spontaneous process and the adsorbing of MPS on cathode was proposed to physical-chemistry adsorption in the plating formula. There was no potential difference (i.e. ?? = 0) of GMs until MPS was injected into the plating solution suggest that copper deposition is not diffusion-controlled in the presence of PEP–Cl–JGB.

A new composition of plating bath was found to be effective to perform bottom-up copper filling of microvias in the fabrication of PCB in electronic industries. The adsorption of MPS into the Cu-RDE metal surface was a spontaneous process and the adsorbing of MPS on cathode was studied by EIS and the results proposed to physical-chemistry adsorption in the plating formula. An optimal plating solution composed of CuSO4, H2SO4, chloride ions, PEP, MPS and JGB was obtained, and the microvia could be fully filled using the plating formula.

This paper aims to study the possibility of electroplating copper coatings on chemically and chemical-galvanically nickel-plated acrylic fibers, to be further processed into yarn, fabrics, knitwear and nonwoven materials.

Electrically conductive fibers with different copper contents have been obtained, and the effect of electrolyte pH, its composition, current strength at the first and second cathodes, as well as the metallization time on the electrophysical, physical and mechanical properties of copper-containing fibers, has been studied.

The studies have shown that with an increase in the copper content, the electrical conductivity, the uniformity of the coating and the uniformity of the electrophysical properties (for chemical-galvanically nickel-plated fiber) increase. In the case of copper plating of chemically nickel-plated fiber, the coefficient of variation in electrical resistance increases with increasing plating time, even though the copper content increases, and the coefficient of variation in copper content and electrical resistance decreases. The physical and mechanical properties of copper-containing fibers differ slightly from the original (subjected to copper plating) and industrial Nitron fibers. With copper plating, the strength of the fiber practically does not decrease, and the elongation decreases somewhat, compared with the mass-produced Nitron fiber.

The physical and mechanical properties of copper-containing fibers are quite high, which makes it possible to be successfully further processed into yarn, fabrics, knitwear and nonwoven materials.

The uniformity of electrodeposition is the key to successful application of pattern plating because the quality of electrodeposited copper layer has a huge impact on the performance of printed circuit boards (PCBs). The multi-physics coupling technology was used to accurately analyze and forecast the characteristics of electrochemical system. Further, an optimized plating bath was used to achieve a uniform electrodeposition.

A multi-physics coupling numerical simulation based on the finite element method was used to optimize electrodeposition conditions in pattern plating process. The influences of geometric and electrochemical factors on uniformity of current distribution and electrodeposited layer thickness were discussed by multi-physics coupling.

The model results showed that the distance between cathode and anode and the insulating shield had a great impact on uniformity of electrodeposition. By numerical simulation, it had been proved that using an auxiliary cathode was an effective and simple way to improve uniformity of electrodeposition due to redistributing of the current. This helped to achieve more uniform surface of the copper patterns by preventing the edge effect and the roughness of the copper layer was reduced to 1 per cent in the secondary current distribution model.

The research is still in progress with the development of high-performance computers.

A multi-physics coupling platform is an excellent tool for quickly and cheaply studying the process behaviors under a variety of operating conditions.

The numerical simulation method has laid the foundation for the design and improvement of the plating bath.

By multi-physics coupling technology, we built a bridge between theoretical and experimental study for control of uniformity of pattern plating in PCB manufacturing. This method can help optimize the design of plating bath and uniformity of pattern plating in PCB manufacturing.

In through‐hole plated double‐sided and multilayer printed circuit boards, electroplated copper forms the main electrically conductive path on hole walls. To ensure high reliability of electrical connection during component assembly, soldering and subsequent service, the properties of process solutions and deposits must be controlled. This paper discusses the methods of measuring and controlling copper plating processing parameters to achieve the optimum deposit properties. Plating pre‐treatment is discussed also as this can influence significantly process performance.

This paper explores the capability of electroless copper deposition plus acid copper electroplating to metallize high aspect ratio microvias.