열충격 시험을 통한 자동차 전장품에 적용되는 칩저항의 전극재와 박리 현상에 관한 연구

이준기(Lee, Joon Ki),송민식(Song, Min Sik),우성종(Woo, Sung Jong),이도영(Lee, Do Young),김상수(Kim, Sang Soo) 한국신뢰성학회 2019 한국신뢰성학회 학술대회논문집 Vol.2019 No.10

최근 환경적 유해를 이유로 납, 수은 등의 특정 유해물질의 사용이 금지되었고 자동차 배기규제가 강화되면서 기존의 유연솔더를 대신하여 납이 없는 무연솔더가 개발되고 적용되고 있다. 특히 자동차 파워트레인 전장제품들은 엔진룸에 장착이 되며 필드 사용 시 사용 환경의 온도가 -40~125도까지 이기때문에 실내 전장품(-40~85도) 대비 스트레스 조건이 높은 환경에 노출이 되고 있어 높은 신뢰성을 요구하고 있다. 또한 최근 자동차 전장품에 대한 연구 개발이 소형화, 고성능화, 다기능화 되면서 수많은 반도체와 칩부품들이 적용되고 있어 솔더 접합부의 파손 및 크랙, 그리고 소자 내부 접합재와 하우징간의 박리 현상 등은 파워트레인 전장제품에서 나타나는 주요 이슈 중의 하나이다. 가장 널리 사용되는 일반적인 칩 부품으로는 칩저항, 칩캐패시터, 칩배리스터 등이 있는데, 그동안 많은 연구와 논문을 통해서 칩저항을 실장하는 무연솔더 크랙에 대한 연구결과는 쉽게 확인을 할 수 있다. 하지만, 본 연구에서는 엔진룸에 장착이 되며 무연솔더와 칩저항이 모두 적용되는 ECU(엔진제어기)를 제작한 후 열충격 시험을 수행하여 칩저항과 칩저항을 실장한 무연솔더의 고장 패턴 및 매커니즘을 분석하였는데, 특히 저항 내부 접합재와 알루미늄 기판간의 박리 현상에 대해 연구를 하였다. Recently, the use of certain harmful substances, such as lead and mercury, was banned due to environmental regulations, and lead-free solder has been developed and applied on behalf of eutectic solder due to strict vehicle emission regulations. In particular, automotive powertrain electronic products are mounted in the engine compartment and the temperature of the used environment is -40 to 125 degrees Celsius when used in the field, which exposes high stress conditions compared to indoor electronic equipment (-40 to 85 degrees) and requires high reliability. Also, as research and development on automotive electronics has become miniaturized, high-performance and multifunctional recently, a number of semiconductor and chip parts are being applied, breaking and crack of solder joints, and delamination phenomena between element internal bonding material and housing are among the major issues appearing in powertrain electronics. Among the most widely used common chip parts are chip resistance, chip capacitor and chip varistor, the results of research on lead-free solder crack that seals chip resistance through many studies and papers so far can be easily verified. In this study, we analyzed the failure of patterns and mechanisms of lead-free solder with chip resistance by testing ECU (Engine Control Unit) mounted in engine room which is applied with both lead free solder and chip resistance. In particular, the phenomenon of delamination between resistive internal bonding material and almuminum housing was studied.

Board level reliability analysis of chip resistor assemblies under thermal cycling: A comparison study between SnPb and SnAgCu

한창운,한봉태 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.3

Accelerated thermal cycling (ATC) tests are conducted for various chip resistor assemblies using the lead-based (SnPb) and lead-free(SnAgCu) solders. The corresponding life prediction models are developed by employing the well-established energy density approach. The life prediction model constants are obtained from the ATC test data. The models are utilized to predict the lifetimes of chip resistorassemblies under a mobile device field condition. The analysis indicates that the lead-free solder used in the chip resistor assembly wouldoffer a longer lifetime under a field condition compared to the lead-based solder regardless of chip resistor types even when a reversetrend is observed in the ATC test results.

저항소자를 이용한 휴대형 Real-time PCR 기기용히터 제작

최형준,김정태,구치완 한국전기전자학회 2019 전기전자학회논문지 Vol.23 No.1

A heater in a portable real-time polymerase chain reaction(PCR) system is one of the important factors for controllingthe PCR thermocycle precisely. Since heaters are integrated on a small-sized PCR chip for rapid heating and fabricatedby semiconductor processes, the cost of producing PCR chips is high. Here, we propose to use chip resistors as aninexpensive and accurate temperature control method. The temperature distribution was simulated using one or two chipresistors on a real-time PCR chip and the PCR chip with uniform temperature distribution was fabricated. Thetemperature rise and fall rates were 18°C/s and 3°C/s, respectively. 바이오샘플의 DNA를 대량 증폭할 수 있는 휴대형 실시간 중합효소연쇄반응(Real-time PCR) 기기에서 히터는 PCR 반응온도를 제어하기 위한 중요한 요소 중의 하나이다. 보통 빠른 히팅을 위해 소형 PCR 칩에 집적화되어 있고, 반도체 공정을이용하여 박막형태로 제작되어 PCR 칩 제작 단가가 높은 편이다. 따라서 본 연구에서는 값싸고 온도제어를 정확히 할 수 있는 히터로 칩 저항을 사용하는 것을 제안한다. 칩 저항을 사용한 히터는 구조가 단순하고 제작이 쉽다는 장점이 있다. 2.54× 2.54 cm² 크기의 실시간 PCR 칩 위에 칩 저항을 1개 또는 2개를 사용했을 때 온도분포를 시뮬레이션 하였고, 고른 온도분포를 갖는 PCR 칩을 제작했다. 또한 효율적인 PCR 칩 냉각을 위해 소형 fan이 내장된 하우징을 설계하였고, 3D 프린터로제작했다. 온도제어는 마이크로프로세서를 이용한 PID제어법(Proportional-Integral-Differential control)을 적용했다. 온도상승비와 하강비는 각각 18℃/s, 3℃/s이며, 각 PCR 반응 단계의 유지 시간을 30초로 하였을 때, 한 사이클은 약 2.66분이 걸렸고, 35 사이클은 약 93 분 내로 진행할 수 있었다.

Circuit modeling and implementation of a biological neuron using a negative resistor for neuron chip

Yunseok Heo,송한정 한국바이오칩학회 2012 BioChip Journal Vol.6 No.1

The implementation of a silicon neuron based on an OTA(operational transconductance amplifier) with a negative resistor for neuron chip is described. The proposed time-varying silicon neuron consists of a coupled oscillator representing the cell body and a current-controlled negative resistor with an input summing junction. SPICE (simulation program with integrated circuit emphasis) simulation results showed that a neuron pulse is generated above a threshold input current of 70 nA. In addition, we performed simulations of a three-neuron chain connected by two synapses to confirm signal transmission. The proposed circuit was fabricated using a 0.5 μm double-poly-CMOS (complementary metal-oxide semiconductor) technology. Measurements of the fabricated single neuron and three-neuron chain were carried out by applying an input stimulus in condition of 5V DC power supply, and the results were compared to the simulations.

고장예지를 위한 온도사이클시험에서 칩저항 실장솔더의 고장메커니즘 연구

한창운(Changwoon Han),박노창(Nohchang Park),홍원식(Wonsik Hong) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

A thermal cycle test was conducted on the chip resistor solder joint with a real-time failure monitoring. To detect the failure of the chip resistor solder joint during the test, the resistance between both ends of resistor is monitored until failure occurs. Monitored resistance was first observed to fluctuate linearly according to the temperature change. Initial aberration of the resistance occurred during the temperature decreasing time of the thermal cycle. More serious change of the resistance followed after some cycles at the temperature increasing time of the thermal cycle. To explain the failure patterns of solder joint, a mechanism for the solder failure was suggested and proved through FE simulations. Based on the explained failure mechanism, it was shown that a prognostics for the solder failure can be implemented by monitoring the resistance change in a thermal cycle condition.

고장예지를 위한 온도사이클시험에서 칩저항 실장솔더의 고장메커니즘 연구

한창운(Changwoon Han),박노창(Nohchang Park),홍원식(Wonsik Hong) 대한기계학회 2011 大韓機械學會論文集A Vol.35 No.7

본 논문에서는 칩저항을 실장하는 솔더에 대한 온도사이클 시험을 수행하고, 그 결과로부터 고장 예지 실현을 위한 열하중에서의 솔더실장의 고장메커니즘을 연구하였다. 시험 중 솔더의 고장을 모니터링하기 위하여 실장된 칩저항 양단간의 저항 변화를 데이터 측정기로 실시간 관찰하였다. 관찰 데이터로부터 솔더의 크랙 진전 중과 크랙 진전 완료 시점의 고장 메커니즘을 제시하였다. 제시된 고장 메커니즘을 유한요소법으로 검증하여 솔더의 크랙이 진전 중에는 저온조건에서 크랙이 열리고 저항이 증가하며, 크랙의 진전이 완료된 후에는 고온조건에서 크랙이 열리고 저항이 증가하는 조건으로 바뀜을 보였다. 이런 결과에 기반하여 온도 사이클에서 저항측정을 통해 칩저항 실장 솔더의 고장예지가 가능함을 제시하였다. A thermal cycling test was conducted on a chip resistor solder joint with real-time failure monitoring. In order to study the failure mechanism of the chip resistor solder joint during the test, the resistance between both ends of the resistor was monitored until the occurrence of failure. It was observed that the monitored resistance first fluctuated linearly according to the temperature change. The initial variation in the resistance occurred at the time during the cycle when there was a decrease in temperature. A more significant change in the resistance followed after a certain number of cycles, during the time when there was an increase in the temperature. In order to explain the failure patterns of the solder joint, a mechanism for the solder failure was suggested, and its validity was proved through FE simulations. Based on the explained failure mechanism, it was shown that prognostics for the solder failure can be implemented by monitoring the resistance change in a thermal cycle condition.

온도변화 환경에서 칩저항 실장용 유·무연솔더의 수명모델 검증연구

한창운(Changwoon Han) 대한기계학회 2016 大韓機械學會論文集A Vol.40 No.3

최근에 온도변화 환경에서 칩저항 실장용 유·무연 솔더의 수명예측모델이 개발되었다. 개발된 수명예측모델에 의하면 가속조건에서는 칩저항 실장 무연솔더가 유연솔더보다 수명이 적은 것으로 나타나지만, 실제조건에서는 무연솔더의 신뢰성이 유연솔더보다 우수하다. 본 연구에서는 개발된 수명예측 모델의 검증 연구를 수행한다. 수명예측모델을 다른 칩저항 실장 유·무연 솔더 시험 결과에 적용하고 비교하기 위해서, 유한요소모델을 개발하고 시험 온도사이클 조건을 적용한다. 변형율 에너지 밀도를 계산하고 수명을 예측한다. 마지막으로 유·무연 솔더에 대해서 예측결과를 시험결과와 비교한다. 검증결과는 개발된 수명예측모델이 사용 가능한 범위에서 수명을 예측할 수 있음을 보인다. Recently, life prediction models for Pb-based and Pb-free solders used in chip resistor assemblies under thermal cycling have been introduced. The models suggest that the field lifetimes of Pb-free solders would be better than those of Pb-based solders when used for chip resistors under thermal cycling conditions, while the lifetime of the chip assemblies under accelerated test conditions show a reverse relationship. In this study, the prediction models were verified by applying the model to another research case. Finite element models were built, thermal cycling conditions were applied, and the energy densities were calculated. Finally, life prediction analysis was conducted for the cases where Pb-based and Pb-free solders were used. The prediction results were then compared with the test data of the case. It was verified that the predictions of the developed life cycle models are on the practical scale.

세라믹 칩저항 제조를 위한 스크린 프린팅 공정의 유동 해석에 관한 연구

박선명(S. M. Park),강익수(I. S. Kang),박철우(C.W. Park),최현진(H. J. Choi) 한국정밀공학회 2015 한국정밀공학회 학술발표대회 논문집 Vol.2015 No.12월

자이로센서와 저항센서를 이용한 보행분석

강성재,안승찬,김영호 대한인간공학회 2002 대한인간공학회 학술대회논문집 Vol.- No.-

A new reliable portable gait phase detection system for patients with various pathological gait was developed in this study. Using FSR (force sensing resistor) and a miniature gyroscope-chip sensor. An algorithm to determine seven different transitions between the four gait phases: stance, heel-off, swing, and heel-strike. A self-designed insole with FSR sensors keep in one"s shoes and the gyroscope sensor was attached to the posterior aspect of the shoes. A controller was attached to waist. Experiments were performed on normal healthy male volunteers, synchronized with a three-dimensional motion analysis system. Results showed that the delay to determine heel-strike and point of varing from heel-off to swing was significantly reduced with the developed gait phase detection system. The developed gait phase detection system will be helpful not only to determine pathological gait phases but to apply prosthetics, orthotics and functional electrical stimulation to many patients.

세라믹 칩저항의 고효율 스크린 프린팅용 듀얼헤드 시스템 개발

강익수(I. S. Kang),최현진(H. J. Choi),박철우(C. W. Park),정원(W. Jung),김연준(Y. J. Kim),권태화(T. H. Kwon) 한국생산제조학회 2016 한국생산제조시스템학회 학술발표대회 논문집 Vol.2016 No.11