• 한국신뢰성학회지:신뢰성응용연구
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• 제11권3호
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• pp.245-249
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• 2011

Through the test of ESD(Electro Static Discharge) for PCB circuit, we are able to research on the ESD effect. This paper also studys on the ESD test method for measurement. In the measurement of the discharge current, we used current probe(TC-1). The applied voltage to the PCB metal is -3 kV HBM mode. In conclusion ESD influences exponentially greater impact in nearer PCB circuit.

• 마이크로전자및패키징학회지
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• 제12권2호
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• pp.167-174
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• 2005

전자 부품의 크기가 점점 줄어들고 고집적화됨에 따라 전자 패키지 내부에 사용되는 금속간 간격이 줄어들고 있다. 이에 더하여 고온 고습한 환경에서 금속간에 전압이 인가되면 금속의 이온화가 촉진, 금속으로 이루어진 필라멘트가 형성되어 결국 절연파괴에 이르게 된다. 이러한 현상이 electrochemical migration(ECM)이다. 이에 인쇄회로기판을 사용하여 ECM 특성 평가를 수행하였다. 항온/항습조건($85^{\circ}C,\;85{\%}RH$)에서 PCB의 $300 {\mu}m$의 단자간격을 가진 through-hole via 표면에서 발생하는 ECM 현상은 CAF가 절연파괴의 주된 메커니즘이었다. solder를 구성하는 Sn과 Pb 조성 분석을 통해 Pb 의 이온 이동도가 Sn의 이온 이동도보다 큰 것을 알 수 있었으며 이는 급격한 양극용해 거동을 보이는 pure Pb의 분극거동과 상관관계가 있는 것으로 사료된다. 또한 시간에 따른 절연파괴시간 시험을 통하여 ECM에 의한 절연파괴시간이 인가전압에 의존하며 인가전압 의존성 지수값(n)은 2로 나타났다.

• 한국전자파학회논문지
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• 제21권9호
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• pp.940-946
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• 2010

본 논문에서는 휴대용 컴퓨터 내 WWAN 대역에서 동작 가능한 평판 회로 기판형 내장형 안테나를 제안하였다. 제안된 안테나는 GSM850/900 대역에서의 안테나 특성을 개선하기 위하여 평판 회로 기판 위에 인쇄되어 있는 기판을 제거한 후 패턴의 일부를 금속 구조체로 대체하였다. 제안된 안테나는 가로 74 mm, 세로 11 mm, 높이 0.5 mm의 크기로 금속 구조체를 사용하지 않은 평판 회로 기판형 안테나와 비교하였을 때 유사한 크기를 가졌음에도 불구하고 해당 주파수 대역에서 약 42 %의 대역폭 증가 특성을 보였다. 금속 구조체를 사용한 GSM850/900 대역에서 측정된 방사 이득의 경우 -4.45~-2.29 dBi로 금속 구조체를 사용하지 않은 안테나보다 높은 방사 이득 특성을 보였다.

• 제어로봇시스템학회논문지
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• 제16권5호
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• pp.469-475
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• 2010

This paper presents a method of classifying discolored defects of metal pads using geometric texture for AFVI (Automated Final Vision Inspection) systems. In PCB manufacturing process, the metal pads on PCB can be oxidized and discolored partly due to various environmental factors. Nowadays the discolored defects are manually detected and rejected from the process. This paper proposes an efficient geometric texture feature, SUTF (Symmetry and Uniformity Texture Feature) based on the symmetric and uniform textural characteristics of the surface of circular metal pads for automating AFVI systems. In practical experiments with real samples acquired from a production line, 30 discolored images and 1232 roughness images are tested. The experimental results demonstrate that the proposed method using SUTFs provides better performance compared to Gabor feature with 0% FNR (False Negative Rate) and 1.46% FPR (False Positive Rate). The performance of the proposed method shows its applicability in the real manufacturing systems.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.545-545
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• 2007

Recently, innovative process has been investigated in order to replace the conventional high-cost micro patterning processes on the electronic products. To produce desirable profit margins from this low cost products, printed circuit board(PCB), will require dramatic changes in the current manufacturing philosophies and processes. Innovative process using metal nano particles replaces the current industry standard of subtractive etched of copper as a highly efficient way to produce robust circuitry on low cost substrates. An advantage of using metal nano particles process in patterned conductive line manufacturing is that the process is additive. Material is only deposited in desired locations, thereby reducing the amount of chemical and material waste. Simply, it just draws on the substrate as glass epoxy or polyimide with metal nano particles. Particles, when their size becomes nano-meter scale, show some specific characteristics such as enhanced reactivity of surface atoms, decrease in melting point, high electric conductivity compared with the bulk. Melting temperature of metal gets low, the metal nano particles could be formated onto polymer substrates and sintered under $300^{\circ}C$, which would be applied in PCB. It can be getting the metal line of excellent electric conductivity.

• 전기학회논문지
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• 제59권11호
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• pp.2038-2042
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• 2010

In this paper, we confirmed the thermal & optical properties for improving the heat transfer coefficient by changing the via hole size and in FR4 PCB with the same area. Osram 1W power LED Package (Golden Dragon) was used and the K-factor which is relative constant between LED junction temperature and forward bias was measured with power source meter(KEITHLEY 2430) to measure the thermal resistance from PCB configuration. As results, thermal resistance in metal PCB came out to the lowest as $26 [^{\circ}C/W]$ and thermal resistance in FR4 PCB without via-holes emerged as the highest as $69 [^{\circ}C/W]$. However thermal resistance of FR4 PCB could have decreased until $32[^{\circ}C/W]$ in 0.6 mm by using the via hole. Also, the luminous flux could have improved, too.

• 한국전기전자재료학회논문지
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• 제23권10호
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• pp.759-762
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• 2010

In this investigation, the effects of $N_2/(Ar+N_2)$ gas partial pressure on the structural, electrical, and thermal properties of AlN dielectric layers prepared on aluminum substrates using RF-magnetron sputtering method were analyzed. Among the films, the AlN dielectric film deposited under $N_2/(Ar+N_2)$ gas partial pressure of 75% exhibit the highest AlN (002) preferred orientation, which was grain size of about 15.32 nm and very dense structure. We suggest the possibilities of it's application as a dielectric layer for metal PCB because the AlN films prepared at optimized gas partial pressure can improving the insulating property, the thermal conductivity, and thermal diffusivity of the films.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권2호
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• pp.68-71
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• 2006

Active thermography has been used for several years in the field of remote non-destructive testing. It provides thermal images for remote detection and imaging of damages. Also, it is based on propagation and reflection of thermal waves which are launched from the surface into the inspected component by absorption of modulated radiation. For energy deposition, it use external heat sources (e.g., halogen lamp or convective heating) or internal heat generation (e.g., microwaves, eddy current, or elastic wave). Among the external heat sources, the ultrasound is generally used for energy deposition because of defect selective heating up. The heat source generating a thermal wave is provided by the defect itself due to the attenuation of amplitude modulated ultrasound. A defect causes locally enhanced losses and consequently selective heating up. Therefore amplitude modulation of the injected ultrasonic wave turns a defect into a thermal wave transmitter whose signal is detected at the surface by thermal infrared camera. This way ultrasound thermography(UT) allows for selective defect detection which enhances the probability of defect detection in the presence of complicated intact structures. In this paper the applicability of UT for fast defect detection is described. Examples are presented showing the detection of defects in PCB material. Measurements are performed on various kinds of typical defects in PCB materials (both Cu metal and non-metal epoxy). The obtained thermal image reveals area of defect in row of thick epoxy material and PCB.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.229-229
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• 2012

Adhesion of Copper film on the aluminum oxide layer formed by anodizing an aluminum plate was enhanced by applying ion beam mixing method. Forming an conductive metal layer on the insulating oxide surface without using adhesive epoxy bonds provide metal-PCB(Printed Circuit Board) better thermal conductivities, which are crucial for high power electric device working condition. IBM (Ion beam mixing) process consists of 3 steps; a preliminary deposition of an film, ion beam bombardment, and additional deposition of film with a proper thickness for the application. For the deposition of the films, e-beam evaporation method was used and 70 KeV N-ions were applied for the ion beam bombardment in this work. Adhesions of the interfaces measured by the adhesive tape test and the pull-off test showed an enhancement with the aid of IBM and the adhesion of the ion-beam-mixed films were commercially acceptable. The mixing feature of the atoms near the interface was studied by scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy.

• 조명전기설비학회논문지
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• 제23권8호
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• pp.8-13
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• 2009

LED 광원 기술의 발전과 더불어 응용분야도 다양하게 넓어지고 있다. 이중 본 논문에서는 액정 후면 배광 장치와 같이 고성능의 광원이 요구되는 응용제품에 적합한 광원을 제작하였다. 논문에서 제안한 광원은 금속산화물 절연층을 이용하여 LED chip에서 발생한 열을 효율적으로 외부로 전달하는 구조를 적용하였으며 패키지 구조가 아닌 chip과의 접촉면에 반사컵 구조를 적용하여 배광 분포 제어와 광자 재흡수 특성을 개선하였다.