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In this work, silver nitrate, thiourea, bisphenol A diglycidyl ether (BADGE), and propylene glycol methyl ether (PM) were selected for designing a silver(I)-complex to trigger the deposition of inductance coil on PET film through electroless copper plating. The most stable silver(I)-complex structure is formed when the ratio of thiourea molecules and silver ions is 3 to 1 by quantum chemical calculations based on density functional theory (DFT). Meanwhile, XRD test demonstrates that the white precipitate crystallized from PM solution of thiourea and silver nitrate is [Ag(SC(NH2)2)3]NO3, which is consistent with theoretical calculations. The cross section of PET film with copper patterns and interconnection holes characterized by metallurgical microscope proves that the silver(I)-complex is able to initiate copper deposition on the surface and through hole wall of PET film. The measured inductance values at operating frequency from 1 to 50 MHz indicate that the fabricated flexible inductor is capable of being integrated into flexible electronics when the bending angles are within 45°. Additionally, the inductor can also be utilized as an angel sensor when the bending angles are in the range of 60° to 180° at 10 MHz.

PurposeCopper electrodeposition acts as a crucial step in the manufacture of high-density interconnect board. The stability of plating solution and the uniformity of copper electrodeposit are the hotspot and difficulty for the research of electrodeposition. Because a large number of factors are included in electrodeposition, experimentally determining all parameters and electrodeposition conditions becomes unmanageable. Therefore, a multiphysics coupling technology was introduced to investigate microvia filling process, and the mechanism of copper electrodeposition was analyzed. The results provide a strong theoretical basis and technical guidance for the actual electroplating experiments. The purpose of this paper is to provide an excellent tool for quickly and cheaply studying the process behavior of copper electrodeposition without actually needing to execute time-consuming and costly experiments.Design/methodology/approachThe interactions among additives used in acidic copper plating solution for microvia filling and the effect on the copper deposition potential were characterized through galvanostatic measurement (GM). The adsorption behavior and surface coverage of additives with various concentrations under different rotating speeds of working electrode were investigated using cyclic voltammetry (CV) measurements. Further, a microvia filling model was constructed using multiphysics coupling technology based on the finite element method.FindingsGM tests showed that accelerator, inhibitor and leveler affected the potential of copper electrodeposition, and bis(3-sulfopropyl) disulfide (SPS), ethylene oxide-propylene oxide (EO/PO) co-polymer, and self-made leveler were the effective additives in acidic copper plating solution. CV tests showed that EO/PO–Cu+-Cl−complex was adsorbed on the electrode surface by intermolecular forces, thus inhibiting copper electrodeposition. Numerical simulation indicated that the process of microvia filling included initial growth period, the outbreak period and the stable growth period, and modeling result was compared with the measured data, and a good agreement was observed.Research limitations/implicationsThe research is still in progress with the development of high-performance computers.Practical implicationsA multiphysics coupling platform is an excellent tool for quickly and cheaply studying the electrodeposited process behaviors under a variety of operating conditions.Social implicationsThe numerical simulation method has laid the foundation for mechanism of copper electrodeposition.Originality/valueBy using multiphysics coupling technology, the authors built a bridge between theoretical and experimental study for microvia filling. This method can help explain the mechanism of copper electrodeposition.

In this work, the leveling effect of two typical levelers for copper electroplating, Janus Green B (JGB) and polymerizates of imidazole and epichlorohydrin (IMEP) are both analyzed through computational calculations and electrochemical experiments. Frontier Molecule Orbital (FMO) and the electrostatic potential (ESP) of JGB, IMEP and accelerated complex MPS-Cu(I) are calculated and visualized by Density Functional Theory (DFT) method to predict the preferable reaction sites for electrophilic or nucleophilic attack and the corresponding interactions. The adsorption processes of JGB and IMEP with MPS-Cu(I) on copper surface are examined through molecular dynamics (MD) simulation. According to the results of calculations, we conclude that IMEP is the better candidate for electroplating at high current density in comparison with JGB. The results from electrochemical tests validate that MPS has both synergistic and antagonistic effect with IMEP and has an antagonistic effect with JGB. Electroplating tests confirms that the system with IMEP exhibits a better leveling effect at higher current density. In addition, relatively higher ESP value is preferred for a leveler in a large current density electroplating.

Methyltriethoxysilane-treated BaFe12O19 particles were added into poly (phenylene oxide) (PPO) to obtain a composite system in the condition of benzoyl peroxide as an initiator. Thermal stability, structure, mechanical behavior and dielectric and magnetic properties were characterized to investigate the effects of BaFe12O19 particles on the performance of PPO-based composites. BaFe12O19/PPO composites were employed as embedded magnetic core to enhance the inductance of spiral copper inductors. Inductance value and quality (Q)-factor of the spiral copper inductor increased to 1.58 μH and 40.2 at 30 MHz respectively when 50 wt% BaFe12O19 particles were added into PPO matrix for a composite system as an embedded magnetic core.

Phosphorus ore flotation tailings (POFTs) are solid wastes produced in the phosphorus flotation process, and most of the POFTs are directly discharged into the tailing yard without treatment. In this study, modified phosphorus ore flotation tailings (MPOFTs) were synthesized by a hydrothermal chemical modification method as an efficient adsorbent to remove MB. The MPOFTs, the effect of initial MB concentrations, reaction time and pH on the MB characterization, and the adsorption mechanism of MB were studied. The results showed that modification of POFTs had a great BET specific surface area (151.26 m2/g). The maximum adsorption capacity of MPOFTs for MB was 321.5 mg/g at an initial pH of 5.94, the initial MB concentration was 1400 mg/L, and the reaction time was 60 min and 293 K. Moreover, the kinetic adsorption data were well described by both Elovich and pseudosecond order models, while the isotherm data were best fitted by Langmuir model. A thermodynamic analysis indicated that the adsorption process was spontaneous and exothermic adsorption. This study provides a new method for the resource utilization of POFTs.

The microvia filling process used in the high-density interconnect printed circuit board manufacturing industry was investigated by multi-physical coupling technology. To achieve a perfect ...

Cyanate/epoxy (CE/EP) was added with surface-modified silica (SiO2) particles to form a composite system. Microstructure of the composites was observed to find the dispersion effect of SiO2 particles in the CE/EP matrix. Thermal conductivity, thermal stability and dielectric properties were also tested to investigate the effects of SiO2 particles. CE/EP-based composite with 50 wt% SiO2 exhibited thermal conductivity of 0.492 W.m−1.K−1, thermal decomposition temperature of 420 °C and dielectric constant of 4.1 at 1 MHz.