• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.6
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• pp.55-66
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• 2016

Power gating is one of effective techniques for reducing leakage current in semiconductor chip. However, power gating cell (PGC) which is used to switch the power source causes performance degradation and the associated reliability problem by increasing IR drop. However, the newly raised problem caused by different scaling properties between gates and metal wires demands additional considerations in power gating design. In this paper, we propose a robust cell placement based power gating design method for reducing the area for power gating cell and metal routing thus to meet IR drop requirement. Experimental results by applying the proposed techniques on the application processor for smartphone fabricated in 28nm CMOS process show that power gating cell area is reduced by 16.16% and maximum IR drop value is also decreased by 8.49% compared to existing power gating cell placement techniques.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.245-246
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• 2008

• Journal of Applied Reliability
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• v.7 no.1
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• pp.1-11
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• 2007

This paper presents a derating design approach for reliability improvement of a regulator IC. The IC is usually used in SMPS. The main failure mechanism of interest is voltage drop due to the package delamination mainly caused by two stresses, i.e. temperature and current. The lifetime under stresses is modeled as a function of stresses and time using accelerating life testings. Quantitative and qualitative variation in lifetime according to stress variations are investigated using the modeled lifetime. Stress levels would be determined to achieve required reliability levels in the aspect of derating design for reliability.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.10
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• pp.447-453
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• 2001

This paper presents the unified reliability evaluation technique of distribution system. To calculate accurate reliabi1ity and reliability indices which can consider line limitation and voltage drop of distribution system, we employed the deterministic evaluation technique with PLOC technique. And to evaluate the distribution system, we presented the evaluating method which is based on Analytic network process. As a result, we can evaluate the distribution system and build the expansion planning of the system considering system load and reliability indices.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.4
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• pp.87-92
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• 2008

The interface microstructure of Sn-3.5Ag/Cu joint was modified by electroplating varying amount of Zn on Cu UBM. As the amount of Zn dissolved in Sn-3.5Ag solder increased with the electroplating Zn thickness, Cu-Sn IMCs such as $Cu_6Sn_5$ and $Cu_3Sn$ were replaced by Zn-containing IMCs such as $Cu_5Zn_8$ and $Ag_5Zn_8$, which increased the drop reliability of solder joints significantly. When the amount of Zn dissolved in solder was about 3.8wt%, drop resistance was best due to the effective suppression of Cu-Sn IMC and voids at the interface.

• Journal of Korea Water Resources Association
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• v.35 no.6
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• pp.665-675
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• 2002

It is very closely related with the reliability of the pipe network to predict pipe burst and diminish burst effect in water distribution system. Most of the engineers have not consider pipe layout and the effect of pipe burst in conservative pipe network design. In this study, The effect of pipe burst in the network is analyzed with respect to pipe network geometric topology and the method of increasing the system reliability is presented by reducing pipe-burst effect. In existing pipe system, it is only designed to the closed loop system but in case of each pipe burst, it cannot transmit appropriate water to consumers and occurs severe hydraulic head drop in many nodes. The techniques developed in this study allow proper pipe diameter and pipe layout to pipe system through the analysis of pipe-burst effect. Thus, when each pipe is bursted, pipe system is prevented from severe pressure head drop in demand nodes and can supply stable flowrate to consumer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.3
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• pp.59-67
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• 2000

This paper describes the unified reliability evaluation with partial loss of continuity for Inchon international airport distribution system which is complex and difficult system to implement. To evaluate reliability considering line limitation and voltage drop of the system, PLOC technique which is based on deterministic evaluation technique and failure mode & effective analysis method is employed. And reliability indices calculation method is used. Finally, to evaluate the system performance and to improve the reliability of the system, Analytic network process method is employed. As a result, calculating accurate reliability, finding weak points, and expansion scheduling of the system is possible.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.11-17
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• 2009

The drop impact reliability comes to be important for evaluation of the life time of mobile electronic products such as cellular phone. The drop impact reliability of solder joint is generally affected by the kinds of pad and reflow number, therefore, the reliability evaluation is needed. Drop impact test proposed by JEDEC has been used as a standard method, however, which requires high cost and long time. The drop impact reliability can be indirectly evaluated by using high speed shear test of solder joints. Solder joints formed on 3 kinds of surface finishes OSP (Organic Solderability Preservation), ENIG (Electroless Nickel Immersion Gold) and ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) was investigated. The shear strength was analysed with the morphology change of intermetallic compound (IMC) layer according to reflow number. The layer thickness of IMC was increased with the increase of reflow number, which resulted in the decrease of the high speed shear strength and impact energy. The order of the high speed shear strength and impact energy was ENEPIG > ENIG > OSP after the 1st reflow, and ENEPIG > OSP > ENIG after 8th reflow.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.378-383
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• 2004

The Korean Performance Demonstration(KPD) System for the ultrasonic testing personnel, equipments and procedures applicable to the Class 1 and 2 piping examination for nuclear power plant in Korea has been established. A round robin test was conducted in order to compare the examination results by the method of Performance Demonstration(PD) with the traditional dB-drop method. The round robin test shows that the reliability of the PD method is better than that of the dB-drop method. As a result, adoption of the PD method to the in-service inspection of the nuclear power plants will improve the reliability of the ultrasonic test results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.826-833
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• 2010

Electric-thermal-structural actuated compliant mechanisms are mechanisms onto which electric voltage drop is applied as input instead of force. This mechanism is based on thermal expansion of material while being heated. Compliant mechanisms are designed subjected to electric charge input using BESO(bi-directional evolutionary structural optimization) method. Reliability-based topology optimization (RBTO) is applied to the topology design of actuators. performance measure approach (PMA), which has probabilistic constraints that are formulated in terms of the reliability index, is adopted to evaluate the probabilistic constraints. In this study, BESO method is used to obtain optimal topology of compliant mechanisms from initial design domain. PMA approach is used to evaluate reliability index. The procedure has been tested in numerical applications and compared with the results obtained by other methods to validate these approaches.