• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.47-53
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• 2012

Bonding strength of Sn-3.0Ag-0.5Cu solder joint due to degradation characteristic of OSP surface finish was investigated, compared with SnPb finish. The thickness variation and degradation mechanism of organic solderability preservative(OSP) coating were also analyzed with the number of reflow process. To analyze the degradation degree of solder joint strength, FR-4 PCB coated with OSP and SnPb were experienced preheat treatment as a function of reflow number from 1st to 6th pass, respectively. After 2012 chip resistors were soldered with Sn-3.0Ag-0.5Cu on the pre-heated PCB, the shear strength of solder joints was measured. The thickness of OSP increased with increase of the number of reflow pass by thermal degradation during the reflow process. It was also observed that the preservation effect of OSP decreased due to OSP degradation which led Cu pad oxidation. The mean shear strength of solder joints formed on the Cu pads finished with OSP and SnPb were 58.1 N and 62.2 N, respectively, through the pre-heating of 6 times. Although OSP was degraded with reflow process, the feasibility of its application was proven.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.44-49
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• 2023

In the global pursuit of carbon neutrality, the rapid increase in the adoption of electric vehicles (EVs) has led to a corresponding surge in the demand for batteries. To achieve high efficiency in electric vehicles, considerations of weight reduction and battery safety have become crucial factors. Copper and aluminum, both recognized as lightweight materials, can be effectively joined through laser welding. However, due to the distinct physical characteristics of these two materials, the process of joining them poses technical challenges. This study focuses on conducting simulations to identify the optimal laser parameters for welding copper and aluminum, with the aim of streamlining the welding process. Additionally, a Graphic User Interface (GUI) program has been developed using the Python language to visually present the results. Using machine learning image data, this program is anticipated to predict joint success and serve as a guide for safe and efficient laser welding. It is expected to contribute to the safety and efficiency of the electric vehicle battery assembly process.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.2
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• pp.69-77
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• 2024

Due to the miniaturization and multifunctionality of electronic devices, a surface mount technology in the form of molded interconnect devices (MID), which directly forms electrodes and circuits on the plastic injection parts and mounts components and parts on them, is being introduced to overcome the limitations in the mounting area of electronic components. However, when using plastic injection parts with low thermal stability, there are difficulties in mounting components through the conventional reflow process. In this study, we developed a process that utilizes induction heating, which can selectively heat specific areas or materials, to melt solder and mount components without causing any thermal damage to the plastic. We designed the shape of an induction heating Cu coil that can concentrate the magnetic flux on the area to be heated, and verified the concentration of the magnetic flux and the degree of heating on the pad part through finite element method (FEM). LEDs, capacitors, resistors, and connectors were mounted on a polycarbonate substrate using induction heating to verify the mounting process, and their functionality was confirmed. We presented the applicability of a selective heating process through magnetic induction that can overcome the limitations of the reflow method.

• Journal of Welding and Joining
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• v.30 no.2
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• pp.65-69
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• 2012

Environmental and health concerns over the lead have led to investigation of the alternative Pb-free solders to replace commonly used Pb-Sn solders in microelectronic packaging application. The leading candidates for lead-free solder alloys are presently the near eutectic Sn-Ag-Cu alloys. Therefore, extensive studies on reliability related with the composition have been reported. However, the insufficient drop property of the near eutectic Sn-Ag-Cu alloys has demanded solder compositions of low Ag content. In addition, the solder interconnections in automobile applications like a smart box require significantly improved vibration resistance. Therefore, this study investigated the effect of alloying elements (Ag, Bi, In) on the vibration fatigue strength. The vibration fatigue was conducted in 10~1000Hz frequency and 20Grms. The interface of the as-soldered cross section close to the Cu pad indicated the intermetallic compound ($Cu_6Sn_5$) regardless of solder composition. The type and thickness of IMC was not significantly changed after the vibration test. It indicates that no thermal activities occurred significantly during vibration. Furthermore, as a function of alloying composition, the vibration crack path was investigated with a focus on the IMCs. Vibration crack was initiated from the fillet surface of the heel for QFP parts and from the plating layer of chip parts. Regardless of the solder composition, the crack during a vibration test was propagated as same as that during a thermal fatigue test.

• Journal of Welding and Joining
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• v.13 no.3
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• pp.134-146
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• 1995

Aluminium nitride(AlN) is currently under investigation as potential candidate for replacing alumium oxide(Al$_{2}$ $O_{3}$) as a substrate material for for electronic circuit packaging. Brazing of aluminium nitride(AlN) to Cu with Ag base active alloy containing Ti has been investigated in vacuum. Binary Ag$_{98}$ $Ti_{2}$(AT) and ternary At-1wt.%Al(ATA), AT-1wt.%Ni(ATN), AT-1wt.% Mn(ATM) alloys showed good wettability to AlN and led to the development of strong bond between brate alloy and AlN ceramic. The reaction between AlN and the melted brazing alloys resulted in the formation of continuous TiN layers at the AlN side iterface. This reaction layer was found to increase by increase by increasing brazing time and temperature for all filler metals. The bond strength, measured by 4-point bend test, was increased with bonding temperature and showed maximum value and then decreased with temperature. It might be concluded that optimum thickness of the reaction layer was existed for maximum bond strength. The joint brazed at 900.deg.C for 1800sec using binary AT alloy fractured at the maximum load of 35kgf which is the highest value measured in this work. The failure of this joint was initiated at the interface between AlN and TiN layer and then proceeded alternately through the interior of the reaction layer and AlN ceramic itself.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.343-349
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• 2020

This study is cases study of sustainable eco-friendly cosmetics packages. The importance of eco-friendly packages has been increasing as environmental issues have recently emerged around the world. Domestic cosmetics industry are releasing sustainable package designs with these changes, but they are limited. In this study, sustainable package criteria were divided and analyzed based on each of the five prior studies of domestic and foreign cases. Studies have confirmed that there is no diversity in the materials and designs of sustainable packages in Korea compared with other countries. Also, it could be seen that there was the lack of consumer-led eco-friendly campaigns. Starting point of research, it is expected that this study may help continue to study better sustainable cosmetics packages in the future.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.5
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• pp.69-78
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• 2014

The paper recycling becomes more important technology in terms of the reduction of the municipal waste and of saving natural resource such as wood. However the more utilization of recycled fiber would result in the higher contaminants in the papermaking processes and in the deterioration of the paper quality. The oil marks in the paper products becomes one of the major defects of paper products originated from paper recycling. The coagulation of various stickies in recycled fiber stock led to the oil marks. In this work, we applied functional polymer additives such as the dispersing agents, the fixing agents and the hydrophobic talc powder for the control of those stickies in order to remove the oil marks. The addition of the talc powder showed the great reduction in the oil marks of the packaging paper products. The hydrophobic surface of the talc particles collected the individual sticky materials and prevented their aggregation in the recycled fiber stock, which resulted in the great reduction of the oil marks on the paper products.

• Journal of Preventive Medicine and Public Health
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• v.54 no.4
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• pp.275-283
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• 2021

Objectives: The workplace is an ideal place for encouraging health-promoting behaviors. Therefore, the aim of the present study was to determine the effect of an empowerment program on the health-promoting behaviors of women workers. Methods: This randomized clinical trial was conducted with 80 women workers employed at a food packaging facility in 2020. The subjects were selected using convenience sampling and were classified into intervention and control groups using block randomization. An empowerment program for women workers was conducted across 6 sessions based on an empowerment model. Data collection tools included a demographic questionnaire and the Health Promoting Lifestyle Profile-II, which participants completed both before the program and 8 weeks after the last session. Data analysis was performed in SPSS version 16 using descriptive analysis and inferential statistics. Results: There were no significant differences between the 2 groups in various health-promoting behaviors before the program. However, the intervention group's scores for nutrition (34.92±1.09 vs. 27.87±4.23), physical activity (24.40±2.94 vs. 17.40±5.03), stress management (26.35±2.60 vs. 23.05±4.27), spiritual growth (34.02±3.00 vs. 30.22±5.40), interpersonal relationships (30.82±2.38 vs. 27.60±4.61), and health responsibility (31.60±2.71 vs. 28.22±4.59) were significantly higher than the control group's 8 weeks after the program had ended. Moreover, there was a significant difference in the total score of health-promoting behaviors for the intervention group compared to the control group (179.00±9.22 vs. 151.42±20.25, p=0.001). Conclusions: An empowerment program for women workers led to significant improvements in the health-promoting behaviors of the participants. Similar programs can ultimately improve women's health in the workplace.

• Journal of Intelligence and Information Systems
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• v.29 no.3
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• pp.79-101
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• 2023

The current status of local road pavement management in Jeollabuk-do only relies on the accomplishments of the site construction company's pavement repair and is only managed through Microsoft Excel and word documents. Furthermore, the budget is irregular each year. Accordingly, a systematic maintenance plan for local roads is necessary. In this paper, data related to road damage and road environment were collected and processed to derive possible areas which could suffer from road damage. The effectiveness of the methodology was reviewed through the on-site inspection of the area. According to the Ministry of Land, Infrastructure and Transport, in 2018, the number of damages on general national roads were about 47,000. In 2019, it reached around 38,000. Furthermore, the number of lawsuits regarding the road damages were about 93 in 2018 and it increased to 119 in 2019. In the case of national roads, the number of damages decreased compared to 2018 due to pavement repairs. To measure the priorities in maintenance of local roads at Jeollabuk-do, data on maintenance history, local port hole occurrence site, overlapping business section, and emergency maintenance section were transformed into data. Eventually, it led to improvements in maintenance of local roads. Furthermore, spatial data were constructed using various current status data related to roads, and finally the data was processed into a new form that could be utilized in machine learning and predictions. Using the spatial data, areas requiring maintenance on pavement were predicted and the results were used to establish new budgets and policies on road management.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.19-24
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• 2020

In this work, the electrical property of Si-doped β-Ga2O3 was investigated via a post-growth annealing process. The Ga2O3 samples were annealed under air (O-rich) or N2 (O-deficient) ambient at 800~1,200℃ for 30 mins. There was no correlation between the crystalline quality and the electrical conductivity of the films within the experimental conditions explored in this work. However, it was observed the air ambient led to severe degradation of the film's electrical conductivity while N2-annealed samples exhibited improvement in both the carrier concentration and Hall mobility measured at room temperature. Interestingly, the x-ray photoemission spectroscopy (XPS) revealed that both annealing conditions resulted in higher concentration of oxygen vacancy (VO). Although it was a slight increase for the air-annealed sample, high resistivity of the film strongly suggests that VO cannot be a shallow donor in β-Ga2O3. Therefore, the enhancement of the electrical conductivity of N2-annealed samples must be originated from something other than VO. One possibility is the activation of Si. The XPS analysis of N2-annealed samples showed increasing relative peak area of Si 2p associated with SiOx with increasing annealing temperature from 800 to 1,200℃. However, it was unclear whether or not this SiOx was responsible for the improvement as the electrical conductivity quickly degraded above 1,000℃ even under N2 ambient. Furthermore, XPS suggested the concentration of Si actually increased near the surface as opposed to the shift of the binding energy of Si from its initial chemical state to SiOx state. This study illustrates the electrical changes induced by a post-growth thermal annealing process can be utilized to probe the chemical and electrical states of vacancies and dopants for better understanding of the electrical property of Si-doped β-Ga2O3.