• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2004년도 ISMP Pb-free solders and the PCB technologies related to Pb-free solders
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• pp.211-219
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• 2004

A new alloy definition will be presented concerning increasing demands for the board level reliability of miniaturized interconnections. The damage mechanism for LFBGA components on different board finishes is not quite understood. Further demands from mobile phones are the drop test, characterizing interface performance of different package constructions in relation to decreased pad constructions and therefore interfaces. The paper discusses the characterization of interfaces based on SnPb, SnPbXYZ, SnAgCu and SnAgCuInNd ball materials and SnAgCuInNd as solder paste, the stability after accelerated tests and the description of modified interfaces stric시y related to the assembly conditions, dissolution behavior of finishes on board side and the influence of intermetallic formation. The type of intermetallic as well as the quantity of intermetallics are observed, primaliry the hardness, E modules describing the ability of strain/stress compensation. First results of board level reliability are presented after TCT-40/+150. Improvement steps from the ball formulation will be discussed in conjunction to the implementation of lead free materials. In order to optimize ball materials for area array devices accelareted aging conditions like TCTs were used to analyze the board level reliability of different ball materials for BGA, LFBGA, CSP, Flip Chip. The paper outlines lead-free ball analysis in comparison to conventional solder balls for BGA and chip size packages. The important points of interest are the description of processability related to existing ball attach procedures, requirements of interconnection properties and the knowledge gained the board level reliability. Both are the primary acceptance criteria for implementation. Knowledge about melting characteristic, surface tension depend on temperature and organic vehicles, wetting behavior, electrical conductivity, thermal conductivity, specific heat, mechanical strength, creep and relaxation properties, interactions to preferred finishes (minor impurities), intermetallic growth, content of IMC, brittleness depend on solved elements/IMC, fatigue resistance, damage mechanism, affinity against oxygen, reduction potential, decontamination efforts, endo-/exothermic reactions, diffusion properties related to finishes or bare materials, isothermal fatigue, thermo-cyclic fatigue, corrosion properties, lifetime prediction based on board level results, compatibility with rework/repair solders, rework temperatures of modified solders (Impurities, change in the melting point or range), compatibility to components and laminates.

• 화약ㆍ발파
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• 제34권4호
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• pp.40-45
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• 2016

화약을 사용하는 현장은 발파에 의해 발생되는 소음과 진동의 영향으로 사용상 제약을 받게 되며, 보안물건이 근접해 있는 경우 대부분 기계식굴착에 의해 작업이 이루어지고 있다. 최근 들어 기존의 기계식굴착 구간에 대해, 발파작업에 의한 암반굴착이 확대되고 있으며 이는 전자뇌관에 의해 가능하게 되었다. 하이트로닉($HiTRONIC^{TM}$)은 진보된 전자기술을 이용하여 생산하는 4세대 뇌관으로 뇌관 내부에 IC-Chip을 내장하고 있어 0~15,000ms까지 1ms간격으로 시차를 설정할 수 있다. 또한 높은 정밀도(0.01%)를 구현하여 초정밀발파가 가능하다. 전자뇌관의 수요처는 고속도로 및 철도현장, 대형 석회석 광산을 비롯한 도심지 터파기 등에서 널리 사용되고 있으며 본고에서는 현재 하이트로닉($HiTRONIC^{TM}$)를 사용하고 있는 현장의 사례를 통해 전자뇌관에 대한 이해를 돕고자 한다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.175-176
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• 2006

Electrowetting is prevailing for its various applicability on lap-on-a-chip, and MEMS devices, such as a pump, lens, micro-actuator in the micro-TAS technology. In the usual electrowetting, an AC power is preferred to DC practically. The AC electric field delays the contact angle-saturation, decreases the hysterisis, and is more stable in the view point of dielectric strength. But researches for AC electric field on electrowetting have not been reported very much yet. The different effect of AC on the electrowetting system, especially the effect of a frequency needs to be understood more concretely. In this work, the usual system for electrowetting, water droplet on the dielectric coated electrode (EWOD) is analyzed. Experimental study on the response of contact angles on input frequencies is performed. The simple circuit-model for EWOD system is considered to explain the experimental results. For more concrete understanding, the system is analyzed numerically, where simple AC-conduction model is used. Wetting tensions are analyzed under various input frequency to excavate the experimental results for the responses of the system on input frequencies.

• 마이크로전자및패키징학회지
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• 제19권3호
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• pp.37-41
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• 2012

Cu 본딩을 이용한 웨이퍼 레벨 적층 기술은 고밀도 DRAM 이나 고성능 Logic 소자 적층 또는 이종소자 적층의 핵심 기술로 매우 중요시 되고 있다. Cu 본딩 공정을 최적화하기 위해서는 Cu chemical mechanical polishing(CMP)공정 개발이 필수적이며, 본딩층 평탄화를 위한 중요한 핵심 기술이라 하겠다. 특히 Logic 소자 응용에서는 ultra low-k 유전체와 호환성이 좋은 Ti barrier를 선호하는데, Ti barrier는 전기화학적으로 Cu CMP 슬러리에 영향을 받는 경우가 많다. 본 연구에서는 웨이퍼 레벨 Cu 본딩 기술을 위한 Ti/Cu 배선 구조의 Cu CMP 공정 기술을 연구하였다. 다마싱(damascene) 공정으로 Cu CMP 웨이퍼 시편을 제작하였고, 두 종류의 슬러리를 비교 분석 하였다. Cu 연마율(removal rate)과 슬러리에 대한 $SiO_2$와 Ti barrier의 선택비(selectivity)를 측정하였으며, 라인 폭과 금속 패턴 밀도에 대한 Cu dishing과 oxide erosion을 평가하였다.

• 조명전기설비학회논문지
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• 제20권2호
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• pp.38-44
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• 2006

고본 논문에서는, 구내용 전력선통신 시스템(PLC; Power Line Communication)으로서 연속직교 상관특성을 갖는 이진 코드를 이용한 CDMA(Code Division Multiple Access)시스템 기반의 전력선통신 시스템을 제시하였다. 연속직교 상관특성을 갖는 이진 코드는 주기가 N=4로부터 2의 배수로 계속 확장이 가능하기 때문에 코드발생기의 구현이 용이함과 동시에 ZCD(Zero Correlation Duration)특성을 가짐으로 인해서, 구내용 전력선통신에서 에코특성에 의한 다중경로 및 다중접속으로 인한 간섭문제를 확산코딩기법을 이용하여 근원적으로 해결해주는 역할을 한다. 본 논문에서는 제안한 연속직교 상관특성을 갖는 이진 코드기반의 구내용 전력선통신의 간섭완화 성능을 확인하기 위하여, 임펄스잡음 환경 및 에코특성에 의한 MPI(Multi Path Interference)와 MAI(Multiple Access Interference)와 같은 다양한 간섭환경 하에서의 BER(Bit Error Rate)특성을 정량적으로 분석하고, 모의실험을 통해 제안시스템의 간섭완화 능력을 입증하였다.

• 한국지능시스템학회논문지
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• 제16권4호
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• pp.485-492
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• 2006

본 논문은 휴머노이드 로봇 ISHURO의 분산 제어를 위한 네트웍 구현에 대해 다루고 있다. 일반적으로 휴머노이드형 로봇은 기구학적으로 유연한 동작을 위해 다수의 자유도가 필요하다. 이를 구현하기 위해서는 중앙에서 일괄적으로 처리 하는 것 보다 간결 하면서도 유연성을 줄 수 있는 분산 처리 방법이 선호되고 있다. 분산 처리를 위한 제어기를 구성할 때는 로봇의 모터를 독립적으로 제어하기 위한 제어기가 별도로 필요하며 모듈 간에는 정해진 시간 내에 데이터를 교환할 수 있는 통신 기법이 필요하다. ISHURO의 각 관절은 자체 내에 독립된 DSP를 내장하고 있으며 CAN 네트웍을 이용하여 모듈간의 통신을 하여 구동기를 재어하거나 센서의 값을 모니터링 할 수 있게 되어 있다. 본 논문에서는 이를 위한 통신 구조를 제안하고 필요한 전송 메시지를 정의하고, 전송시간을 분석하여 로봇 분산 제어기 구조에 적절한 전송 프로토콜을 제시하였다. 모든 과정은 Matlab을 이용하여 컴퓨터모의실험을 수행하였고 실제 휴머노이드 로봇에 적용하여 보행실험을 통해 검증 하였다.

• 한국식생활문화학회지
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• 제11권3호
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• pp.305-316
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• 1996

The purpose of this study was to find out how much they have several aspects of food related knowledge and eating behaviors of high school students in Sungnam area. The self-administrated questionnaire was used. The result were as follows: 1. The average height of boys and girls was $172.6{\pm}0.7$ cm and $156.3{\pm}1.5$ cm respectively. The average weights of them were $62.4{\pm}0.5$ kg (male) and $47.2{\pm}0.8$ kg (female). BMI (Body Mass Index) of them were $20.74{\pm}0.14$ (male), $18.82{\pm}0.28$ (female). The average age is 16.7 years old. 2. The 66.5% of the subjects were spent more than one-third of their pocket money in buying on light meals during three times a week. There were significant differences between income level of family. Boys spent more money on each meal than girls. And significant differences were also obserbed by their residence area and Bundang residences spent more in buying snacks. 3. The rate of skipping meals was 51.2% in boys compared with 68.0% in girls. The frequencies of buying snacks instead of main meal were high in girls. Time limits in eating may possibly be the main reason for skipping meals (59.8%), especially in the morning. Skipping a breakfast becomes general eating habits in high school students, because of pressure for time to go to school. 4. It is required that parents should be taught to prepare balanced lunch box for their children because the rate of students who prepared two lunch boxes are 49.4%. 5. The students took snacks once or twice a day. They usually bought snacks in school concessions (51.8%) and they selected items of snack instinctivly. The girls ate snacks during lunch break time (31.7%) and after dinner (23.6%). Boys ate snacks after dinner (29.1%). Preference of foods were different by sex. Boys preferred bread (31.7%), milk and otherdairy products (80.8%), cola and soda (42.0%) as their snacks between meals. Girls selected biscuit, chip, beverage, coffee as their snacks, frequently. 6. BMI value of the group who ate between meals more than three times a day was lower $(18.78{\pm}0.65)$ than that of the group who ate nothing between meals $(20.71{\pm}3.79)$. 7. As for the nutritional knowledge, the students generally had higher correct rate of answer about which nutritive components of food has (76.6%). But they had lower knowledge on questions of nutritive values in food (10.6%). There was a meaningful relation between favorite food and nutritional knowledge. In conclusion, there were some problems on nutritional knowledge and eating habits among the high school students. Therefore, it was required that girls should be learned to recognize the importance of breakfast and needed to select balanced meals and snacks. And it was required that the nutrition education should be complemented to motivate and improve practical eating behaviors.