• Journal of the Microelectronics and Packaging Society
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• v.20 no.4
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• pp.13-16
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• 2013

A lot of various researches have been going on to use heat spreader for LED module. Nano porous aluminum anodic oxide (AAO) applied LED, which is produced from anodization, is easy and economically advantageous. Convensional LED module is consist of aluminum/adhesive/copper circuit. The polymer adhesive in this module is used as heat spreader. However the thermal emission of LED component is degraded because of low heat conductivity of polymer and also reliability of LED component is reduced. Therefore, AAO in this work was applied to heat spreader of LED module which has higher heat conductivity compare to polymer. Bonding strength between AAO and copper circuit was improved with Ti/Cu seed layer by copper sputtering process (DBC) before the bonding. And this copper circuit has been fabricated by electro plating method. Peel strength of AAO and copper circuit in this work showed range between 1.18~1.45 kgf/cm with anodizing process which is very suitable for high power LED application.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.1
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• pp.109-113
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• 2012

The LED failure rate greatly depends on the physical properties of packaging materials (epoxy). The glass transitions temperature (Tg) of the epoxy is one of the most important physical properties. Therefore, in the present study, various epoxies with high Tg were prepared and their failure shapes were analyzed. In addition, the failure shapes depending on the amount of epoxy and the wire bonding structure were measured. As a consequence, the lower failure rate was obtained with the smaller amount of epoxy. The safety of LED was improved with increasing the Tg of the epoxy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4378-4384
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• 2012

In LED chip packaging, die bonding is a very important process which fixes the LED chip on the lead frame to provide enough strength for the next process. This paper focuses on the process optimization of a LED die bonding, which attaches small zener diode chip on PLCC LED package frame, using response surface analysis. Design of experiment (DOE) of 5 factors, 3 levels and 5 responses are considered, and the results are investigated. As the results, optimal conditions those satisfy all response objects can be derived.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.3
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• pp.33-41
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• 2010

Crack propagation mechanisms of Sn-3.0Ag-0.5Cu solder were studied in strain controlled push-pull creepfatigue conditions using the fast-fast (pp) and the slow-fast (cp) strain waveforms at 313 K. Transgranular cracking was found in the pp strain waveform which led to the cycle-dominant crack propagation and intergranular cracking in the cp strain waveform that led to the time-dominant crack propagation. The time-dominant crack propagation rate was faster than the cycle-dominant crack propagation rate when compared with J-integral range which resulted from the creep damage at the crack tip in the cp strain waveform. Clear recrystallization around the crack was found in the pp and the cp strain waveforms, but the recrystallized grain size in the cp strain waveform was smaller than that in the pp strain waveform. The cycle-dominant crack propagated in the normal direction to the specimen axis macroscopically, but the time-dominant crack propagated in the shear direction which was discussed in relation with shear micro cracks formed at the crack tip.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.1
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• pp.19-23
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• 2020

Al-laminated packaging film incorporating ascorbic acid or tocopherol at inner food contact layer was tested in the potential to improve antioxidative preservation of powdered infant formula under CO₂-enriched atmosphere. Product of 200 g was packaged with the packaging film containing 0.3% antioxidant in sealant layer of low density polyethylene and stored at 30℃ for 286 days with periodic measurement of package atmosphere and product's quality attributes. The CO₂-flushed package resulted in shrinkage of tight contact between the product and the film not allowing gas sampling of package atmosphere after 140 days. Package of tocopherol-incorporated film allowed some ingress of oxygen after 112 days presumably due to its weakening of heat-seal area. The increased oxygen concentration in the tocopherol-added film package led to the concomitant increase of peroxide value, an index of lipid oxidation. On the other hand, packaging of ascorbic acid-added film pouch could suppress lipid oxidation marginally in consistent manner compared to control package without any antioxidant.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.149-154
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• 2018

This paper describes the fabrication and heat transfer property of 50 watts rated LED array module where multiple chips are mounted on chip-on-board type ceramic-metal hybrid substrate with high heat dissipation property for high power street and anti-explosive lighting system. The high heat transfer ceramic-metal hybrid substrate was fabricated by conformal coating of thick film glass-ceramic and silver pastes to form insulation and conductor layers, using thick film screen printing method on top of the high thermal conductivity aluminum alloy heat-spreading panel, then co-fired at $515^{\circ}C$. A comparative LED array module with the same configuration using epoxy resin based FR-4 PCB with thermalvia type was also fabricated, then the thermal properties were measured with multichannel temperature sensors and thermal resistance measuring system. As a result, the thermal resistance of the ceramic-metal hybrid substrate in the $4{\times}9$ type LEDs array module exhibited about one third to the value as that of FR-4 substrate, implying that at least triple performance of heat transfer property as that of FR-4 substrate was realized.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.1
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• pp.11-15
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• 2013

In order to find a sanitary logistic way to handle library books, papers and environmental sources contacting the books were tested in their microbial contamination load and methods to decontaminate the books were investigated. Generally bacterial load of inner book pages was very low, but increased when contaminated with liquid such as saliva. In contrast, their lateral ends showed much higher bacterial contamination presumably due to dry dust contamination on there. As operations to improve the sanitary book conditions, turbulent air blow was found to be workable for reducing dry dusty contamination and 280 nm ultra-violet (UV) light emitting diode (LED) was so for decontaminating wet surface contamination. Microbial inactivation by the UV LED could be realized with irradiation for more than 5 minutes at 2 cm distance. Air blow of 5.5 m/s for 0.5~1 minute could reduce the dusty contamination on a model book surface.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.14 no.2
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• pp.81-88
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• 2008

There are increasing public concerns that the disposal of most synthetic carbon-based plastics is a great threat to the environment. These have led to intensive research and development of degradable plastics, such as biodegradable plastics, photodegradable plastics, and multi-degradable plastics. Although these degradable plastics may not completely replace common synthetic plastics, these minimize environmental impacts caused by non degradable plastics. Photodegradable plastics are synthetic polymers into which have been incorporated copolymers or light-sensitive additives to weaken the structural bonds in polymer chains when exposed to UV radiation. A better understanding of photodegradable plastics, which also play an important role in the degradation of multi-degradable plastics, will expand the usage of degradable plastics. The aim of present article is to review the formation, degradation mechanism and properties of photodegradable plastics.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.184-185
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• 2002

We discussed the main issues of 10GHz Receiver packaging. High frequency structure simulations and circuit simulations for TO-CANs led to a new design for 10GHz optical receiver module packaging. The simulation results were compared to the measured laboratory data. The proposed package has low cost and easy manufacture process far mass production. Using this package, we had a good optical to electrical conversion (OE) characteristic at a data rate of 10Gbps.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.6 no.1
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• pp.19-23
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• 2000

The increasing use of plastics in food packaging materials has led to the issue of food-packaging mutual interactions from residues in the plastics. Plastic films are commonly printed by using solvent-based ink to decorate the packaged food for consumer attention. However, the residual solvents can not be completely removed and they can migrate into the contained food which lead to undesirable off-flavors. Partitioning (Kp) of printing ink solvents was studied in two types of plastic films with different chemical structure and polarity. At $25^{\circ}C$, Kp of toluene is higher than that of isopropanol in PP, but isopropanol showed higher Kp value than toluene in EVOH. This showed that polarity had a significant effect on the partitioning of printing ink solvents into the plastic films. Printing solvents had a higher affinity to the polymer with similar polarity than it did to the different one.