In the printed circuit board (PCB) manufacturing industry, the yield is an important management factor as it significantly affects the product cost and quality. However, in real situations, it is difficult to ensure a high yield in a manufacturing process, because the products are manufactured through numerous nanoscale manufacturing operations. Thus, for improving the yield, it is necessary to analyze the key process parameters and equipment parameters that result in a low yield. In this study, critical equipment parameters that affect the yield were extracted through a mutual analysis of the equipment parameters (x) and process parameters (y) in the plastic ball grid array (PBGA) manufacturing process. To this end, the study uses the correlation coefficient to apply the heuristic algorithm that extracts critical parameters that keep the redundancy among the equipment parameters to a minimum and exert maximum impact on the critical process parameters. Additionally, by using the general regression neural network technique, the effects of the critical equipment parameters on the process parameters were confirmed. The test results were applied to the PBGA production line and an improvement in the yield was confirmed.

In this study, a free-fall drop tester was studied to test the impact reliability of small electronic components. The electronic component was fixed to the drop table and the table was fallen along guide rods. The impact energy was adjusted by the initial drop height, and the impact duration time was adjusted by inserted soft layers under the drop table. Table acceleration was achieved in the form of a half-sine that conforms to international standards. The developed tester was evaluated by a small printed circuit board. It was observed that the developed tester was fully utilized for the impact reliability assessment of electronic components.

By patterning finely with a laser with a thickness of 100 μm or less such as ABS and forming an electronic circuit through plating, a high-density flexible PCB applicable to wearable and mobile devices can be realized. ABS films with a thickness of 60, 90, and 120 μm were prepared, and a crater measuring 100 μm or less was formed by irradiating a fiber laser with a wavelength of 1064 nm with a single pulse. The size of the craters is affected by the intensity of laser irradiation and the thickness of the film, and the heat dissipation layer reduces the change in size caused by the difference in the thickness of the film. For films with a thickness of 60 μm, it has been found that small craters of more than 10% can be obtained due to the heat dissipation layer. Thermal analysis showed in the ABS film without the heat dissipation layer, the maximum temperature increased to 373oC, but decreased to 261℃ in the ABS film with the heat dissipation layer. With a decrease in the thickness of the film, the heat dissipation layer further reduces the pattern by laser irradiation.