• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.31-36
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• 2002

The 2nd level solder joint reliability of 153 FC-BGA for high-speed SRAM (Static Random Access Memory) with the large chip on laminate substrate comparing to PBGA(Plastic Ball Grid Array) was studied in this paper. This work has been done to understand an influence as the mounting with single side or double sides, structure of package, properties of underfill, properties and thickness of substrate and size of solder ball on the thermal cycling test. It was confirmed that thickness of BT(bismaleimide tiazine) substrate increased from 0.95 mm to 1.20 mm and solder joint fatigue life improved about 30% in the underfill with the low young's modulus. And resistance against the solder ball crack became twice with an increase of the solder ball size from 0.76 mm to 0.89 mm in solder joints.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.708-711
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• 1999

The Cu/Ni/Au lamellar structure is extensively used as an under bump metallization on silicon file, and on printed circuit board(PCB) pads. Ni is plated Cu by either electroless Ni plating, or electrolytic Ni plating. Unlike the electrolytic Ni plating, the electroless Ni plating does not deposit pure Ni, but a mixture of Ni and phosphorous, because hypophosphite Is used in the chemical reaction for reducing Ni ions. The fracture crack extended at the interface between solder balls of plastic ball grid (PBGA) package and conducting pads of PCB. The fracture is duets to segregation at the interface between Ni$_3$Sn$_4$intermetallic and Ni-P layer. The XPS diffraction results of Cu/Ni/Au results of CU/Ni/AU finishs showed that the Ni was amorphous with supersaturated P. The XPS and EDXA results of the fracture surface indicated that both of the fracture occurred on the transition lesion where Sn, P and Ni concentrations changed.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.153-161
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• 2023

The worldwide effects of COVID-19 have led to a surge in online shopping and contactless services. The consumption pattern has caused the issues such as the environmental pollution together with the increase of plastic waste. Reducing the reliance on the petroleum based plastic use for the package and replacing it with environmentally friendly material are the simple ways in order to solve those problems. Paper is an eco-friendly product with high recyclability as the food packaging materials but has still poor barrier properties. A barrier coating on surface of the paper can be achieved with the proper packaging materials featuring water, gas and grease barrier. Polyethylene (PE) or polypropylene (PP) coatings which are generally laminated or coated to paper are widely used in food packaging applications to protect products from moisture and provide water or grease resistance. However, recycling of packaging containing PE or PP matrix is limited and costly because those films are difficult to degrade in the environment. This study investigated the recyclability of modified acrylic emulsion coating papers compared to PE and PP polymer matrixes as well as their mechanical and gas barrier properties. The results showed that PE or modified acrylic emulsion coated papers had better mechanical properties compared to the uncoated paper as a control. PE or PP coating papers showed strong oil resistance property, achieving a kit rating of 12. Those papers also had a significantly higher percentage of screen reject during the recycling process than modified acrylic coated paper which had a screen rejection rate of 6.25%. In addition an uncoated paper had similar value of a screen rejection rate. It may suggest that modified acrylic emulsion coating paper can be more easily recycled than PE or PP coating papers. The overall results of the study found that modified acrylic emulsion coating paper would be a viable alternative to suggest a possible solution to an environmental problem as well as enhancing the weak mechanical and poor gas barrier properties of the paper against moisture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3442-3447
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• 2014

A simple method to evaluate the hygroscopic characteristics of polymer of microelectronic plastic package is suggested. To evaluate the characteristics, specimens were prepared, and the internally absorbed moisture masses were measured as a function of the absorbing time and calculated numerically. The hygroscopic pressure ratio was calculated by heat transfer analysis supported by commercial FEM code because the hygroscopic diffusion equation has the same form as the heat transfer equation. The moisture masses were then summed by the self developed code. The nonconductive polymers had quite different characteristics for the different lots, even though they were the same products. The absorbed moisture mass variations were calculated for several different characteristics, and the optimal curve of the mass variation close to experimental data was selected, whose solubility and diffusivity were affected by the hygroscopic characteristics of the material. The method can be useful in the industrial fields to quickly characterize the polymer material of the semiconductor package because the fast correspondence is normally required in industry. The weight changes in the aluminum-nonconductive-polymer joint due to moisture absorption were measured. The deformed system was also measured using the Moire Interferometry system and compared with the results of finite element analysis.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.69-73
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• 2010

Finite-element analyses were conducted to investigate the thermal stress in 3-dimensional stacked wafers package containing through-silicon-via (TSV), which is being widely used for 3-Dimensional integration. With finite element method (FEM), thermal stress was analyzed with the variation of TSV diameter, bonding diameter, pitch and TSV height. It was revealed that the maximum von Mises stresses occurred at the edge of top interface between Cu TSV and Si and the Si to Si bonding site. As TSV diameter increased, the von Mises stress at the edge of TSV increased. As bonding diameter increased, the von Mises stress at Si to Si bonding site increased. As pitch increased, the von Mises stress at Si to Si bonding site increased. The TSV height did not affect the von Mises stress. Therefore, it is expected that smaller Cu TSV diameter and pitch will ensure mechanical reliability because of the smaller chance of plastic deformation and crack initiation.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.15 no.2
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• pp.43-47
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• 2009

Respiration and quality of persimmon fruits were monitored through the storage at 0, 5, 15 and $25^{\circ}C$. Respiration rate data at different temperatures were used for determining the $O_2$ and $CO_2$ permeabilities required to maintain the optimal package atmosphere (1~3% $O_2$, 4~7% $CO_2$). The estimated gas permeabilities were then compared to those of available plastic films for examining their potential application at various temperature conditions. $O_2$ consumption and $CO_2$ production were at similar order and leveled at stable value after initial time span with higher rates measured at higher temperatures. Major quality indexes during storage were observed to be ascorbic acid content change and firmness destruction with the most significant changes at $25^{\circ}C$ Higher $O_2$ and $CO_2$ permeabilites were required at higher temperatures, and common plastic films were shown to be unable to satisfy those requirements. Films or devices of high permeation property such as silicone rubber or microporous film may be combined to increase the permeation properties satisfying the required high gas permeabilities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.1104-1109
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• 2005

In this paper, a Ka-band harmonic mixer is designed and fabricated on the base of the multiplier theory that there is a bias point to maximize the third harmonic order($3f_{LO}$) with respect to a fundamental LO frequency($f_{LO}$), which can make the high-order mixing element($f_{RF}{\pm}3f_{LO}$) to be greater than other mixing elements, Pumping a RF frequency($f_{RF}$) and LO frequency($f_{LO}$). The harmonic mixer by the proposed design method is fabricated by using a commercial GaAs MESFET device with a plastic package and overcome these disadvantages that a conventional mixer in Ka-band suffer from a high cost, inefficient productivity and circuit complexity. The harmonic mixer have a -10 dB conversion loss at the IF Sequency($3f_{LO}-f_{RF}$=1.0GHz) by selecting a gate bias voltage for the maximum third-order LO harmonic element($3f_{LO}$=34.5 GHz) as pumping LO frequency($f_{LO}$=11.5 GHz) With respect to RF Sequency ($f_{RF}$=33.5GHz)

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.827-834
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• 2020

In this paper, a third-order harmonic mixer is designed using frequency multiplier theory for the microwave airborne radar. Unlike the basic mixer design method, the gate bias voltage, at which the third-harmonic component of the Local frequency (LO) is the maximum, is selected using a frequency multiplier theory to maximize the third-harmonic mixing component at the intermediate frequency (IF). The proposed harmonic mixer was designed and manufactured using a commercial GaAs MESFET device in a plastic package, and it was possible to improve the high conversion loss, circuit complexity, high cost, and manufacturing complexity of the existing microwave mixer. The harmonic mixer using the proposed design method has a -8 ~ -10 dB conversion loss by pumping 11.5 GHz LO with a +5 dBm level when operating from 33.0 GHz to 36.0 GHz and the 1-dB gain compression point (P1dB) of 0 dBm.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.29-37
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• 2014

Non-Newtonian fluid mechanics takes charge of an important role in the oil industries. Especially in the oil well drilling process, the drilling fluid such as mud keeps the drill bit cool and clean during drilling, with suspending drill cuttings and lubricating a drill bit. The purpose of this study is to examine the effect of fluid mud rheological properties to predict different characteristics of non-Newtonian fluid in the mud mixing tank on offshore drilling platforms. In this paper, ANSYS fluent package was used for the simulation to solve the hydrodynamic force and to evaluate mud mixing time. Prediction of the power consumption and the pumping effectiveness has been presented with different operating fluid models as Newtonian and non-Newtonian fluid. The comparison between Newtonain mud model and non-Newtonian mud model is confirmed by the CFD simulation method of drilling mud mixing tank. The results present useful information for the design of the drilling mud mixing tanks and provide some guidance on the use of CFD tool for such non-Newtonian fluid flow.

• The Journal of the Korea Contents Association
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• v.12 no.5
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• pp.447-458
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• 2012

Korean wave which started from Korean drama is continuing its popularity with K-pop in China. This positive effect has lead to increases in Korean product export to China, increase in number of Chinese visitors to Korea and increase in number of Chinese population learning Hangul. In this research, empirical study was conducted to analyze the influence of Korean wave contents (drama, movie, K-pop, games) on Chinese population (their intention to purchase Korean product, visit Korea and learn Hangul.) As the result, it is understood that the most influential Korean wave content on Chinese population's intention to purchase Korean cosmetic and clothing products is drama; it is analyzed that K-pop has noticeable influence as well. Korean drama has the greatest influence on Chinese population's intention to visit Korea, purchase cosmetic or plastic surgery tour package and purchase Korean food. K-pop is analyzed as the second most influential factor among Korean wave contents in this category. Korean wave contents which have the most influence on intention to learn Hangul are Korean drama and K-pop, and it is analyzed that K-pop has greater influence than Hangul in this field.