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The correlations among magnetic properties, synthesis temperature, and composition of FeCo nanoparticles were investigated herein. Fe80Co20 alloy nanoparticles synthesized at different temperatures (383, 393, 403, 413, 428, and 443 K) showed variable compositions and aggregation degrees of the FeCo nanoparticles. Under the optimized conditions of synthesis temperature of 403 K and duration of 1 h, FeCo nanoparticles were synthesized at molar ratios of 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:9. The FeCo alloy nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, vibrating sample magnetometer, fourier transform infrared, and network analyzer. With increasing Co content, the extent of aggregation increased. The cobalt ferrite phase was detected under some conditions, and all FeCo nanoparticles showed high saturation magnetization and low coercive forces. The prepared FeCo nanoparticles exhibited high permeability at a high frequency range.

A via reliability test of PCB board using embedded MLCC was evaluated by HALT and Pressure Cooker Test PCT. The reliability of HALT was evaluated at 125 , 4Vr, and 12Hr. The purpose of this test was to verify the stability of the MLCC by predicting the lifetime of the PCB. The PCBT conditions were measured at 85% humidity and 2 atm, and the reliability of the PCBs under severe conditions than HALT was evaluated. The basic characteristics of MLCC size are 0603 (600x300um), Capacitance 100nF, thickness 150µm. The initial electrical characteristics of the MLCC size are 0603 (600 x 300 um), Capacitance 100 nF, thickness 150 um. The initial electrical characteristics of the MLCC were measured at a rated voltage (10V) with a capacitance value of 98 ~ 103 nF, a loss rate of 0.048%, and an insulation resistance of 1.08 x 1010 (omega). The HALT test results showed that all the measured samples showed a value of 1 x 107 (omega) or more, and passed for the HALT test. The PCBT test resulted in failure, and the first sample fell below the poor insulation resistance at the start of the PCBT test. In the case of the second sample, the insulation resistance dropped to less than the defective insulation resistance for more than 30 hours, and the third sample has an appropriate insulation resistance of 1.0x106 even for more than 60 hours. It is confirmed that there is the greatest the possibility of failure in the part between the embedded chip and via that Cu plating is performed to form via by fill plating. Therefore, it is necessary to optimize the plating thickness and size conditions because the embedded MLCC has a high probability that defects mainly occur in VIA crack or delamination

We investigated the electrical properties of a unique solid array capacitor with 6 capacitances consisting of 4 electrodes and 3 organic dielectrics in single body. The unique solid array capacitors with 4 electrodes and 3 dielectrics were composed of Cu/organics Di-electric/Cu/organics Di-electric/Cu/organics Di-electric/Cu with horizontal arrays structure. It was made by a new and unique fabrication process. A 4 cu sheet and a 3 organic sheet are stacked up in a vertical direction. The stacked materials are then pressed vertically using temperature, pressure, and time. The pressed samples were mechanically cut into the designed sizes in the transverse and longitudinal directions. When the cutted sample is laid flat, a 4 cu electrode and 3 organic di-electrics can be made a unique solid array capacitor horizontally. A size of the completed array capacitor is 3x4.86x0.5mm and 2.7x3.6x0.5mm. The length of the electrode and organic Di-electric is about 0.5 mm at plane. The thickness of the fabricated array capacitor in the vertical direction is 0.5 mm. It has 6 capacitances with a series-type structure. The capacitance values calculated by the formula and the measured capacitance values were compared with each other. C1, C2, and C3 of Sample1 and Sample2 show that the difference between the calculated value and the measured value is as small as about 5% or less for a 0.349 pF of sample 1 and a 0.301 pF of sample 2. C4, C5, and C6 were compared within 13∼15% of the calculated and measured values. The variation of the measured capacitance was confirmed to be within 15%.