• 마이크로전자및패키징학회지
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• 제10권1호
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• pp.7-11
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• 2003

반도체 칩이나 전자제품에 사용되는 부품들은 작동할 때 발열을 하게 되며 발생한 열이 적절히 제거되지 않을 경우 제품 오작동의 원인이 된다. 이러한 열을 제거하기 위해 히트싱크(heatsink)와 냉각 팬 (cooling fan)을 조합한 냉각 구조가 사용된다. 그러나 히트싱크와 냉각 팬의 조합 구조는 복잡한 형상을 취하기 때문에 전기 전자 제품의 소형화 추세에 부응하기에는 어려움이 따른다. 냉각 효율은 히트싱크의 표면적과 히트싱크 제조시 사용된 재료에 따라 달라진다. 일반적인 냉각 구조의 한계를 극복하기 위한 방안으로써, Trach-etched 멤브레인의 표면과 기공(pore)에 무전해 금도금과 구리 도금을 실행하여 크기는 작으면서 표면적을 증가시킨 마이크로 히트싱크를 제조하였다. 제조한 마이크로 히트싱크의 구조는 주사현미경(SEM)과 광학 현미경으로 관찰하였으며, 일반적인 구리보다 열효율이 우수함을 방열 특성 실험을 통해 관찰하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.475-480
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• 2002

The reliability of the solder joint is affected by type and extent of the interfacial reaction between solder and substrates. Therefore, understanding of intermetallic compounds produced by soldering in electronic packaging is essential. In-based alloys have been favored bonding devices that demand low soldering temperatures. For photonic and fiber optics packaging, m-based solders have become increasingly attractive as a soldering material candidate due to its ductility. In the present work, the interfacial reactions between indium solder and bare Cu Substrate are investigated. For the identification of intermetallic compounds, both Scanning Electron Microscopy(SEM) and X-Ray Diffraction(XRD) were employed. Experimental results showed that the intermetallic compounds, such as Cu$_{11}$In$_{9}$ was observed for bare Cu substrate. Additionally, the growth rate of these intermetallic compounds was increased with the reaction temperature and time. We found that the growth of the intermetallic compound follows the parabolic law, which indicates that the growth is diffusion-controlled.d.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 1998년도 전지기술 심포지움
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• pp.153-166
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• 1998

Lithium ion Batteries commercially available since the early nineties in Japan are going to be more and more important for portable electronic devices and even EV applications. Today several companies around the world are working hard to join to market for Lithium secondary batteries. Based on the growing interest for commercial use of batteries also the materials have to be reviewed in order to meet large scale production needs. The requirements especially for electrolytes for lithium batteries are extremely high. The solvents and the lithium salts should be of highest purity. So the supply of these chemicals including packaging, transportation and storage but also the handling in production are critical items in this field. Frolic impurities are very critical for LiPF6 based electrolytes. The influence of water is tremendous. But also the other protic impurities like alcoholes are playing an Important role for the electrolyte quality. The reaction of these species with LiPF6 leads to formation of HF which further reacts with cathode materials (spinel) and anode. To understand the role of the protic impurities more clearly the electrolyte was doped with such compounds and was analyzed for protic impurities and HF. These results which directly show the relation between impurities and quality will be presented and discussed. In addition several investigations on different packaging materials as well as methods to analyze and handle the sensititive material will be addressed. These questions which are only partly discussed in literature so far and never been investigated systematically cover some of the key parameters for understanding of the battery chemicals. This investigation and understanding however is of major importance for scientist and engineers in the field of Lithium ion and Lithium polymer batteries.

• 한국재료학회지
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• 제14권6호
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• pp.443-450
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• 2004

Parylene polymer thin film shows excellent homogeneous coverage chracteristics when it was deposited onto very complex three dimensional solid matters, such as deep hole and micro crack. The parylene deposition process can be conducted at room temperature although most of chemical vapor deposition processes request relatively high processing temperature. Therefore, the parylene coating process does not induce any thermal problems. Parylene thin film is transparent and has extremly high chemical stability. For example, it shows high chemical stability with high reactive chemical solutions such as strong acid, strong alkali and acetone. The bio-stability of this material gives good chances to use for a packaging of biomedical devices and electronic devices such as display. In this review article, principle of deposition process, properties and application fields of parylene polymer thin film are introduced.

• 마이크로전자및패키징학회지
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• 제25권4호
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• pp.25-34
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• 2018

In this paper, we review the latest technical progress and commercialization of stretchable interconnectors, stretchable strain sensors, and stretchable substrates for stretchable electronics. The development of stretchable electronics can pave a way for new applications such as wearable devices, bio-integrated devices, healthcare and monitoring, and soft robotics. The essential components of stretchable electronic devices are stretchable interconnector and stretchable substrate. Stretchable interconnector should have high stretchability and high electrical conductivity as well as stability under severe mechanical deformation. Therefore several nanocomposite-based materials using CNT, graphene, nanowire, and metal flake have been developed. Geometric engineering such as wavy, serpentine, buckled and mesh structure has been well developed. Stretchable substrate should also pose high stretchability and compatibility with stretchable sensing or interconnecting material. We summarize the recent research results of new materials for stretchable interconnector and substrate as well as strain sensors. The Important challenges in development of the stretchable interconnector and substrate are also briefly discussed.

• 마이크로전자및패키징학회지
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• 제29권4호
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• pp.89-94
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• 2022

고체상태에서 열에너지과 전기에너지를 직접적이고 가역적으로 변환할 수 있는 열전소재는 전기전도특성인 전기전도도 및 제벡계수와 열전도특성인 열전도도에 의해 그 성능이 결정된다. 하지만 전기전도도, 제벡계수, 열전도도는 소재의 조성, 결정구조 및 전자구조에 의해 결정되며, 서로 상관관계를 나타내기 때문에 성능 증대를 위한 효과적인 전략수립에 어려움이 있다. 본 논문에서는 열전소재의 성능과 관련한 수식에 대한 이해를 바탕으로 실험 결과와 연계하여 열전도도 저감 관점에서 효과적인 결함제어 기반 열전소재 성능 증대 전략을 수립할 수 있는 방법론을 제공하고자 한다.

• 한국정밀공학회지
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• 제27권1호
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• pp.91-98
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• 2010

The increasing of power and processing speed and miniaturization of central processor unit (CPU) used in electronics equipment requires better performing thermal management systems. A typical thermal management package consists of thermal interfaces, heat dissipaters, and external cooling systems. There have been a number of experimental techniques and procedures for estimating thermal conductivity of thin, compressible thermal interface material (TIM). The TIM performance is affected by many factors and thus TIM should be evaluated under specified application conditions. In compact packaging of electronic equipment the chip is interfaced with a thin heat spreader. As the package is made thinner, the coupling between heat flow through TIM and that in the heat spreader becomes stronger. Thus, a TIM characterization system for considering the heat spreader effect is proposed and demonstrated in detail in this paper. The TIM test apparatus developed based on ASTM D-5470 standard for thermal interface resistance measurement of high performance TIM, including the precise measurement of changes in in-situ materials thickness. Thermal impedances are measured and compared for different directions of heat dissipation. The measurement of the TIM under the practical conditions can thus be used as the thermal criteria for the TIM selection.

• Corrosion Science and Technology
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• 제6권6호
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• pp.282-285
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• 2007

Smaller size and higher integration of electronic systems make narrower interconnect pitch not only in chip-level but also in package-level. Moreover electronic systems are required to operate in harsher conditions, that is, higher current / voltage, elevated temperature / humidity, and complex chemical contaminants. Under these severe circumstances, electronic components respond to applied voltages by electrochemically ionization of metals and conducting filament forms between anode and cathode across a nonmetallic medium. This phenomenon is called as the electrochemical migration. Many kinds of metal (Cu, Ag, SnPb, Sn etc) using in electronic packages are failed by ECM. Eutectic SnPb which is used in various electronic packaging structures, that is, printed circuit boards, plastic-encapsulated packages, organic display panels, and tape chip carriers, chip-on-films etc. And the material for soldering (eutectic SnPb) using in electronic package easily makes insulation failure by ECM. In real PCB system, not only metals but also many chemical species are included. And these chemical species act as resources of contamination. Model test systems were developed to characterize the migration phenomena without contamination effect. The serpentine-shape pattern was developed for analyzing relationship of applied voltage bias and failure lifetime by the temperature / humidity biased(THB) test.

• 마이크로전자및패키징학회지
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• 제6권1호
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• pp.81-89
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• 1999

Micromachining을 이용하여 기존의 전자 물품 감시에 사용되는 자기공명센서의 소형화 공정을 연구하였다. 설계 한 구조는 Free Standing Membrane형 과 Diving Board형의 두 가지이며 각자에 대해 적합한 공정 조건을 수립하고 실제로 그 구조를 형성해 보았다. 멤브레인형의 경우는 센서 모양을 여러 가지 형태로 쉽게 바꿀 수 있는 반면에 그 크기가 실리콘 기판의 두께에 의존하여 소형화하는데 한계가 있었으며 다이빙 보드형의 경우 소형화에도 유리하고 센서의 자기변형이 보다 자유로운 구조였다. 실리콘 질화막은 일반 반도체 공정에서의 조건보다 Si의 함량을 크게 하여 열처리 없이도 저응력의 박막형성이 가능하였으며 탄성계수 값이 크지 않아 센서 부분의 자기변형을 크게 구속하지 않아 센서물질의 지지층으로 유리한 물질이었다. 또한 스퍼터링으로 증착된 텅스텐은 자성 센서 물질로 연구되고 있는 Fe-B-Si물질에 대한 식각 선택도가 높아 구조 형성 공정 중 보호 층으로 사용된 후 제거될 수 있음을 알 수 있었다. 따라서 지지층으로 실리콘 질화막을 사용하고 보호층으로 텅스텐 박막을 사용한 다이빙 보드형 구조가 전자 물품 감시(EAS)용 센서의 소형화에 유리 할 것으로 생각된다.

• 마이크로전자및패키징학회지
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• 제25권4호
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• pp.95-99
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• 2018

최근 고집적 고출력 전자 패키지의 효율적인 열전달을 위한 기판 및 방열소재로서 절연성 고열전도 필름의 수요가 커지고 있어, 알루미나, 질화알루미늄, 질화보론, 탄소나노튜브 및 그래핀 등의 고열전도 필러소재를 사용한 고방열 복합소재에 대한 많은 연구가 이루어지고 있다. 그 중에서도 육방정 질화보론(h-BN) 나노시트가 절연성 고열전도 필러 소재로서 유력한 후보 물질로 선택되고 있다. 본 연구는 이 h-BN 나노시트와 PVA로 된 세라믹/폴리머 복합체 필름의 방열특성 향상에 관한 것이다. h-BN 나노시트는 h-BN 플레이크 원료 분말을 유기용매를 사용한 볼밀링과 초음파 처리에 의한 물리적 박리공정으로 만들었으며, 이를 사용한 h-BN/PVA 복합 필름을 제조한 결과 성형된 복합필름의 면방향과 두께방향 열전도도는 50 vol%의 필러함량에서 각각 $2.8W/m{\cdot}K$ 및 $10W/m{\cdot}K$의 높은 열전도도가 나타났다. 이 복합필름을 PVA의 유리전이온도 이상에서 일축 가압하여 h-BN 판상분말의 얼라인먼트를 향상시킴으로써 면방향 열전도도를 최대 $13.5W/m{\cdot}K$까지 증가시킬 수 있었다.