• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1673-1678
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• 2007

The use of flip-chip type electronic package offers numerous advantages such as reduced thickness, improved environmental compatibility, and downed cost. Despite numerous benefits, flip-chip type packages bare several reliability problems. The most critical issue among them is their electrical performance deterioration upon consecutive thermal cycles attributed to gradual delamination growth through chip and adhesive film interface induced by CTE mismatch driven shear and peel stresses. The electronic package in use is heated continuously by itself. When the crack at a weak site of the electronic package occurs, thermal deformationon the chip side is changed. Therefore, we can measure these micro deformations by using Moire interferometry and find out the crack length.

• Journal of electromagnetic engineering and science
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• v.11 no.1
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• pp.62-69
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• 2011

This paper proposes a novel electrical characterization approach for a high-performance package system using an improved Partial Element Equivalent Circuit (PEEC). As the effect of interconnects becomes a pivotal factor for the performance of high-speed electronic systems, there is a great demand for an accurate equivalent model for interconnects. In particular, an equivalent model of interconnects is established in this paper for the Fine-Pitch Ball Grid Array (FBGA) package using the improved PEEC method. Based on the equivalent model, electrical characteristics are analyzed; furthermore, these are verified through the measurement results of a Vector Network Analyzer (VNA).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1646-1655
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• 2004

A description of the basic principles of moire interferometry leads to the design of a eight-mirror four-beam interferometer for obtaining fringe patterns representing contour-maps of in-Plane displacements. The technique is implemented by the optical system using an environmental chamber for submicro-displacement mesurement. In order to estimate the reliability and applicabili쇼 of the system developed, the measurement of coefficient of thermal expansion (CTE) for a aluminium block is performed. Consequently, the system is applied to the measurement of thermal deformation of a WB-PBGA package assembly. Temperature dependent analyses of global and local deformations are presented to study the effect of the mismatch of CTE between materials composed of the package assemblies. Bending displacements of the packages and average strains of solder balls are documented. Thermal induced displacements calculated by FEM agree quantitatively with experimental results.

• Journal of the Korea Society of Computer and Information
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• v.22 no.2
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• pp.111-117
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• 2017

This study analyzes the relative importance of the introducing factors for the critical success factors in the implementation stage of the lifecycle of ERP system using Delphi technique and Analytic Hierarchy Process(AHP). In the 1st layer of the hierarchy, technical factor is evaluated as the most important factor among organizational, technical, and supplier factors. In the 2nd layer, choosing a proper ERP package is evaluated as the most important factor within 15 factors followed by process-oriented approach, technical suitability, minimized customization, integration and association of system with trading parter, association with legacy systems, and support and involvement of top management. As a result of this analysis enterprise should choose an ERP package that is suitable to its business environment, and make the best use of(take full advantage of) best practice that ERP package provides to optimize the existing business procedure or process(to approach the existing business procedure or process). This study also shows the range of customization of the features provided by the ERP package should be minimized.

• Korean Management Science Review
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• v.32 no.3
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• pp.55-70
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• 2015

The main objective of this study is to investigate the moderating roles of the competitor's pricing strategy and the degree of consumer's risk-aversion on perceived risk and perceived benefit in responding to price increases and package downsizing. Based on Prospect Theory, several prior researches find that consumers perceive increased price as more loss than package downsizing and perceive package downsizing as more benefit than increased price. We extend these behavioral economics approach using the reference effect of competitor's pricing strategy. We focus on consumer heterogeneity on risk-aversion, measure the degree of consumer's risk-aversion, and divide the consumers into two groups of high levels of risk-aversion vs. low levels of risk-aversion. We find that the firm's pricing strategies of both price increases and package downsizing do not significantly influence the perceived benefit for relatively low risk-aversion consumers. We find that when the firm reduce the package size, relatively high risk-aversion consumers perceived more benefit and had higher purchase intention compared to price increases. We also find that the competitor's pricing strategies do not significantly influence the consumer's response for relatively low risk-aversion consumers. For relatively high risk-aversion consumers, they perceived more loss when the firm has different pricing strategy from the competitor's.

• Journal of Information Technology Applications and Management
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• v.29 no.6
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• pp.145-157
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• 2022

Climate crisis is one of the most urgent and serious threats to the right to life. As AR picture books are particularly effective for safety education, this study aimed to produce an AR picture book featuring animals that are endangered due to the climate crisis. In order to increase the educational effect and enhance the climate sensitivity, this study developed a children's activity workbook (with follow-up activities) and a teacher's guide (with lesson plans) as a package. To this end, market research and surveys were first conducted. Next, through the management and support of the Korea Institute of Startup & Entrepreneurship Development, this research team produced a climate crisis themed AR picture book package through expert advice, help from outsourcing companies, and field application. The package was promoted through publicity in various forms of media. The contents of the AR-using picture book package of this case study were introduced and then advantages and disadvantages were discussed.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.2
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• pp.61-68
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• 2015

Warpage analysis has been performed for top and bottom packages of thin package-on-packages processed with different epoxy molding compounds (EMCs). Warpage deviation was measured for packages molded with the same EMCs and also the warpage deviations of top and bottom substrates themselves were characterized in order to identify the major factor causing the package warpage. For the top and bottom packages processed with thin substrates, the warpage deviation of the substrates was large, which made it difficult to figure out the effect of EMC properties on the package warpage. Top packages, where the molding area of $13mm{\times}13mm$ covered the most of the substrate area ($14mm{\times}14mm$), exhibited similar warpage behavior with changing the temperature. On the other hand, bottom packages, where the molding area was only $8mm{\times}8mm$, exhibited the complex warpage behavior due to simultaneous occurrence of (+) and (-) warpages on the same package. Accordingly, the bottom packages showed dissimilar temperature-warpage behavior even being processed with the same EMCs.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.4
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• pp.1-7
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• 2006

A major failure mode for wafer level chip size package (WLCSP) is thermo-mechanical fatigue of solder joints. The mechanical strains and stresses generated by the coefficient of thermal expansion (CTE) mismatch between the die and printed circuit board (PCB) are usually the driving force for fatigue crack initiation and propagation to failure. In a WLCSP process peripheral or central bond pads from the die are redistributed into an area away using an insulating polymer layer and a redistribution metal layer, and the insulating polymer layer affects solder joints reliability by absorption of stresses generated by CTE mismatch. In this study, several insulating polymer materials were applied to WLCSP to investigate the effect of insulating material. It was found that the effect of property of insulating material on WLCSP reliability was altered with a solder ball layout of package.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.3
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• pp.203-210
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• 2021

With the development of package printing technology, the package has expanded from the basic function of protecting products to the marketing function through package design. Color, the visual element that composes the package design, is delivered to the consumer most quickly and effectively. As color marketing of these package designs expands, accurate color reproduction that the product wants to express is becoming more important. The color of an object is transmitted by absorption and scattering of light. Spectral reflectance refers to the intensity of light reflected by an object at different wavelengths by the spectral effect. As a result, the color of the object is expressed in various colors. Packaged printing inks have their own absorption and scattering coefficients, and the Kubelka-Munk model for color reproduction and prediction defines the relationship between these correlation coefficients through reflectance. In the Kubelka-Munk model for color reproduction and prediction, the relationship between the absorption and scattering coefficients (K/S) of printed material is predicted as the sum of the K/S values according to the mixing ratio of all color ink used. In this study, the reflectance of the measured print is reversely calculated at the mixing ratio of print ink using the Kubelka-Munk model. Through this, the relationship value of the ink-specific absorption/scattering coefficient constituting the final printed material is predicted. Delta E is derived through the predicted reflectance, and the similarity between the measured value and the predicted value is confirmed.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.31-39
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• 2021

In this paper, warpage analysis that separates PCB for PoP (Package on Package) into unit and substrate using FEM (Finite Element Method), analysis of the effect of layer thickness on warpage, and SN (Signal-to-Noise) ratio by Taguchi method was carried. According to the analysis result, the contribution of the circuit layer on warpage was very high in the unit PCB, and the contribution of the outer layer was particularly high. On the other hand, the substrate PCB had a high influence of the circuit layer on warpage, but it was relatively low compared to the unit PCB, and the influence of the solder resist was rather increased. Therefore, considering the unit PCB and the substrate PCB at the same time, it is desirable to design the PCB for PoP layer-by-layer structure so that the outer and inner circuit layers are thick, the top solder resist is thin, and the thickness of the bottom solder resist is between 5 ㎛ and 25 ㎛.