Copper coin-embedded printed circuit board for heat dissipation: manufacture, thermal simulation and reliability

Purpose - The purpose of this paper is to form copper coin-embedded printed circuit board (PCB) for high heat dissipation. Design/methodology/approach - Manufacturing optimization of copper coin-embedded PCB involved in the design and treatment of copper coin, resin flush removal and flatness control. Thermal simulation was used to investigate the effect of copper coin on heat dissipation of PCB products. Lead-free reflow soldering and thrust tests were used to characterize the reliable performance of copper coin-embedded PCB. Findings - The copper coin-embedded PCB had good agreement with resin flush removal and flatness control. Thermal simulation results indicated that copper coin could significantly enhance the heat-dissipation rate by means of a direct contact with the high-power integrated circuit chip. The copper coin-embedded PCB exhibited a reliable structure capable of withstanding high-temperature reflow soldering and high thrust testing. Originality/value - The use of a copper coin-embedded PCB could lead to higher heat dissipation for the stable performance of high-power electronic components. The copper coin-embedded method could have important potential for improving the design for heat dissipation in the PCB industry

Effects of surface-functionalized aluminum nitride on thermal, electrical, and mechanical behaviors of polyarylene ether nitrile-based composites

Aluminum nitride (AlN) with high thermal conductivity was blended in polyarylene ether nitrile (PEN) to obtain a composite system. A ball milling process could provide AlN particles of smaller size with higher surface silylation for homogeneous particle distribution in polymeric matrix. Thermal, electrical, and mechanical behaviors of the produced composites were characterized to investigate the effects of particles on the performance of PEN-based composites with functionalized AlN. The composite exhibited thermal conductivity of 0.779 W m−1 K−1, a dielectric constant of 7.7, dielectric loss of 0.032, electrical resistivity of 1.39 GΩ.cm, and break strength of 36 N when the fraction of functionalized AlN increased to 42.3 vol%. A fitted equation based on the improved Russell's model could effectively predict a trend for thermal conductivity of the composite systems with consideration of interfacial resistance between AlN and surrounding PEN

Efficient Vibrational Energy Transfer through Covalent Bond in Indigo Carmine Revealed by Nonlinear IR Spectroscopy

Ultrafast vibrational relaxation and structural dynamics of indigo carmine in dimethyl sulfoxide were examined using femtosecond pump–probe infrared and two-dimensional infrared (2D IR) spectroscopies. Using the intramolecularly hydrogen-bonded CO and delocalized CC stretching modes as infrared probes, local structural and dynamical variations of this blue dye molecule were observed. Energy relaxation of the vibrationally excited CO stretching mode was found to occur through covalent bond to the delocalized aromatic vibrational modes on the time scale of a few picoseconds or less. Vibrational quantum beating was observed in magic-angle pump–probe, anisotropy, and 2D IR cross-peak dynamics, showing an oscillation period of ca. 1010 fs, which corresponds to the energy difference between the CO and CC transition frequency (33 cm^–1). This confirms a resonant vibrational energy transfer happened between the two vibrators. However, a more efficient energy-accepting mode of the excited CO stretching was believed to be a nearby combination and/or overtone mode that is more tightly connected to the CO species. On the structural aspect, dynamical-time-dependent 2D IR spectra reveal an insignificant inhomogeneous contribution to time-correlation relaxation for both the CO and CC stretching modes, which is in agreement with the generally believed structural rigidity of such conjugated molecules