• ETRI Journal
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• 제33권4호
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• pp.645-647
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• 2011

In this study, a microcapillary pumped loop (MCPL) that can be used as a cooling device for small electronic and telecommunications equipment has been developed. For thin devices such as an MCPL, securing a vapor flow space is a critical issue for enhancing the thermal performance. In this letter, such enhancement in thermal performance was accomplished by eliminating condensed droplets from the vapor line. By fabricating the grooves in the vapor line to eliminate droplets, a decrease in thermal resistance of about 63.7% was achieved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1301-1302
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• 2006

In this paper, embedded spiral inductors are investigated into the PCB substrate for low cost RF SOP applications. The spiral inductors designed with geometrical variations were simulated, fabricated, measured, and characterized by using 3D EM simulator, 8 layered PCB standard process and HP 8510B network analyzer (or verifying their applicability. The fabricated embedded spiral inductor has inductance of 9.4 nH at 800MHz, maximum quality factor of 64.8 at 1.09GHz and self resonant frequency of 3.93GHz, respectively. As the measured inductances and quality factors are well matched with simulated ones. PCB embedded spiral inductors are promising for advanced electronic systems with various functionality, low cost, small size and volume.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.222-222
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• 2007

RF circuit을 구현하는데 있어서 기판의 전기적 특성을 정확하게 아는 것은 원하는 결과를 추출하기 위해 매우 중요하다. 본 연구에서는 현재 사용되고 있는 PI 기판의 전기적인 특성인 유효 유전율과 loss tangent 값을 T-resonator률 이용해 정확하게 측정하고자 했다. T-resonator는 microstrip 구조로 구현 되었으며 conductor material은 Cu를 사용하였다. PI 기판의 두께는 25um, Cu의 두께는 PI 기판의 종류에 따라 12um 와 18um, T-resonator line width는 50um로 구현하였다. 또한 공진 주파수에 따라 stub 길이가 다른 10개의 T-resonator를 제작하였다. PI 기판의 유효 유전율을 구하기 위해 stub 길이의 open-end effect와 T-junction effect를 고려하였으며 수식을 통해 정확한 유효 유전률을 추출하였다. 또한 PI 기판의 loss tangent 추출에 필요한 dielectric loss를 추출하기 위해 unload quality factor를 분석하였다. Unload quality factor는 dielectric loss, conductor loss, radiation loss를 구성되며 conductor loss와 radiation loss를 수식에 의해 구하고 dielectric loss를 추출 하였다. 추출 된 dielectric loss를 통해 각각의 T-resonator의 loss tangent 값을 구하였다. T-resonator를 이용한 PI 기판의 측정은 비교적 복잡한 수식에 의해 이루어지지만 정확한 data를 얻을 수 있고 다른 재료의 전기적 특성을 추출하는데 응용이 가능하다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.210-210
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• 2007

RF circuit을 구현하는데 있어서 기판의 전기적 특성을 정확하게 아는 것은 매우 중요하다. 왜냐하면 초고주파로 갈수록 기판의 전기적인 특성이 circuit에 많은 영향을 미치고 이러한 영향을 고려한 circuit를 설계해야 원하는 결과를 얻을 수 있기 때문이다. 본 연구에서는 현재 사용되고 있는 PI 기판의 전기적인 특성인 유효 유전율과 loss tangent 값을 캐패시터를 이용해 정확하게 측정하고자 했다. 캐패시터의 conductor material은 Cu를 사용하였고 PI 기판의 투께는 25um 를 이용하였다. PI 기판의 유효 유전율은 캐패시터 측정에 의한 data률 EM simulation tool 을 통해 분석한 후 간단한 수식에 의해 구했다. 또한 PI 기판의 loss tangent 값을 구하기 위해 캐패시터의 dissipation factor를 분석하였다. 캐패시터의 dissipation factor는 dielectric loss, AC 저항에 의한 loss, DC 저항에 의한 loss를 포함한다, DC 저항에 의한 loss는 dissipation factor에 차지하는 비율이 낮기 때문에 생략이 가능하다. 하지만 AC 저항에 의한 loss는 주파수에 비례하여 값이 커지게 된다. 따라서 주파수가 올라 갈수록 dissipation factor도 상승하게 되는데 주파수의 전 대역에서 AC 저항에 의한 loss를 보정해주면 dielectric loss를 얻을 수 있다. 추출된 dielectric loss를 통해 PI 기판의 loss tangent 값을 구하였다. 캐패시터를 이용한 PI 기판의 전기적 특성 추출은 간단한 구조를 통해 얻을 수 있기 때문에 다른 재료의 기판의 전기적 특성을 추출하는데도 이용이 용이하다.

• 마이크로전자및패키징학회지
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• 제24권4호
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• pp.9-17
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• 2017

In these days, MEMS (micro-electro-mechanical system) devices become the crucial sensor components in mobile devices, automobiles and several electronic consumer products. For MEMS devices, the packaging determines the performance, reliability, long-term stability and the total cost of the MEMS devices. Therefore, the packaging technology becomes a key issue for successful commercialization of MEMS devices. As the IoT and wearable devices are emerged as a future technology, the importance of the MEMS sensor keeps increasing. However, MEMS devices should meet several requirements such as ultra-miniaturization, low-power, low-cost as well as high performances and reliability. To meet those requirements, several innovative technologies are under development such as integration of MEMS and IC chip, TSV(through-silicon-via) technology and CMOS compatible MEMS fabrication. It is clear that MEMS packaging will be key technology in future MEMS. In this paper, we reviewed the recent development trends of the MEMS packaging. In particular, we discussed and reviewed the recent technology trends of the MEMS bonding technology, such as low temperature bonding, eutectic bonding and thermo-compression bonding.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
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• pp.29-33
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• 2000

MEMS, Micro Electro-Mechanical Systems, present one of the greatest advanced packaging challenges of the next decade. Historically hybrid technology, generally thick film, provided sensors and actuators while integrated circuit technologies provided the microelectronics for interpretation and control of the sensor input and actuator output. Brought together in MEMS these technical fields create new opportunities for miniaturization and performance. Integrated circuit processing technologies combined with hybrid design systems yield innovative sensors and actuators for a variety of applications from single crystal silicon wafers. MEMS packages, far more simple in principle than today's electronic packages, provide only physical protection to the devices they house. However, they cannot interfere with the function of the devices and often must actually facilitate the performance of the device. For example, a pressure transducer may need to be open to atmospheric pressure on one side of the detector yet protected from contamination and blockage. Similarly, an optical device requires protection from contamination without optical attenuation or distortion being introduced. Despite impediments such as package standardization and complexity, MEMS markets expect to double by 2003 to more than ＄9 billion, largely driven by micro-fluidic applications in the medical arena. Like the semiconductor industry before it. MEMS present many diverse demands on the advanced packaging engineering community. With focused effort, particularly on standards and packaging process efficiency. MEMS may offer the greatest opportunity for technical advancement as well as profitability in advanced packaging in the first decade of the 21st century! This paper explores MEMS packaging opportunities and reviews specific technical challenges to be met.

• 마이크로전자및패키징학회지
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• 제21권2호
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• pp.23-29
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• 2014

Less power consumption, lower cost, smaller size and more functionality are the increasing demands for consumer electronic devices. The three dimensional(3-D) TSV packaging technology is the potential solution to meet this requirement because it can supply short vertical interconnects and high input/output(I/O) counts. Cu(Copper) has usually been chosen to fill the TSV because of its high conductivity, low cost and good compatibility with the multilayer interconnects process. However, the CTE mismatch and Cu ion drift under thermal stress can raise reliability issues. This study discribe the thermal stress reliability trend for successful implementation of 3-D packaging.

• 마이크로전자및패키징학회지
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• 제26권4호
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• pp.7-13
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• 2019

Power module is getting attention from electronic industries such as solar cell, battery and electric vehicles. Transient liquid phase (TLP) boding, sintering with Ag and Cu powders and wire bonding are applied to power module packaging. Sintering is a popular process but it has some disadvantages such as high cost, complex procedures and long bonding time. Meanwhile, TLP bonding has lower bonding temperature, cost effectiveness and less porosity. However, it also needs to improve ductility of the intermetallic compounds (IMCs) at the joint. Wire boding is also an important interconnection process between semiconductor chip and metal lead for direct bonded copper (DBC). In this study, TLP bonding using Sn-based solders and wire bonding process for power electronics packaging are described.

• 마이크로전자및패키징학회지
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• 제25권2호
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• pp.1-8
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• 2018

In the soldering industry, a variety of lead-free solders have been developed as a part of restricting lead in electronic packaging. Sn-Ag-Cu (SAC) lead-free solder is regarded as one of the most superior candidates, owing to its low melting point and high solderability as well as the mechanical property. On the other hand, the mechanical property of SAC solder is directly influenced by intermetallic compounds (IMCs) in the solder joint. Although IMCs in SAC solder play an important role in bonding solder joints and impart strength to the surrounding solder matrix, a large amount of IMCs may cause poor strength, due to their brittle nature. In other words, the mechanical properties of SAC solder are of some concern because of the formation of large and brittle IMCs. As the IMCs grow, they may cause poor device performance, resulting in the failure of the electronic device. Therefore, new solder technologies which can control the IMC growth are necessary to address these issues satisfactorily. There are an advanced nanotechnology for microstructural refinement that lead to improve mechanical properties of solder alloys with nanoparticle additions, which are defined as nano-reinforced solders. These nano-reinforced solders increase the mechanical strength of the solder due to the dispersion hardening as well as solderability of the solder. This paper introduces the nano-reinforced solders, including its principles, types, and various properties.

• 마이크로전자및패키징학회지
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• 제21권4호
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• pp.1-13
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• 2014

The paper gives an overview of the concepts, basic requirements, and trends regarding packaging technologies of power modules in hybrid (HEV) and electric vehicles (EV). Power electronics is gaining more and more importance in the automotive sector due to the slow but steady progress of introducing partially or even fully electric powered vehicles. The demands for power electronic devices and systems are manifold, and concerns besides aspects such as energy efficiency, cooling and costs especially robustness and lifetime issues. Higher operation temperatures and the current density increase of new IGBT (Insulated Gate Bipolar Transistor) generations make it more and more complicated to meet the quality requirements for power electronic modules. Especially the increasing heat dissipation inside the silicon (Si) leads to maximum operation temperatures of nearly $200^{\circ}C$. As a result new packaging technologies are needed to face the demands of power modules in the future. Wide-band gap (WBG) semiconductors such as silicon carbide (SiC) or gallium nitride (GaN) have the potential to considerably enhance the energy efficiency and to reduce the weight of power electronic systems in EVs due to their improved electrical and thermal properties in comparison to Si based solutions. In this paper, we will introduce various package materials, advanced packaging technologies, heat dissipation and thermal management of advanced power modules with extended reliability for EV applications. In addition, SiC and GaN based WBG power modules will be introduced.