• 세라미스트
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• 제21권2호
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• pp.83-88
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• 2018

There is close relation between the heat generation and the performance of electronic device. The durability and efficiency of the device are degraded due to heat generation. It is necessary to release the generated heat from an electronic device. Based on demands of the printed circuit board (PCB) manufacturing, the robust and reliable plating technique of PCB is necessary. In this study, we review various methods for improving the heat sink property. These methods were considered to enhance the adhesion between ceramic substrate as heat sink and metal layer as electrode.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.2002-2008
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• 2012

최근 들어 전자제품 소형화로 인한 방열의 중요성이 대두되고 있는 가운데 다양한 소재의 히트싱크가 사용되고 있다. 본 연구에서는 태양광에너지 소재산업에서 발생하는 슬러리로부터 SiC를 성공적으로 분리하여 다공성 세라믹 히트싱크를 개발하였고 알루미늄 히트싱크, 순수 SiC 히트싱크와 방열성능 비교실험을 통해 다공성 재생 SiC 세라믹 히트싱크의 방열성능을 검증하였다. 실험 결과, 다공성 재생 SiC는 알루미늄 히트싱크 대비 방열성능이 우수함을 확인하였는데 이는 미세기공으로 인한 전열면적 증가에 기인한다. 또한, 수치해석을 사용하여 미세기공이 방열성능에 미치는 영향을 대류열전달계수 증가로 정량화하였다.

• 마이크로전자및패키징학회지
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• 제23권4호
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• pp.35-41
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• 2016

고출력 LED 조명용 패키지를 제조함에 있어서 발열은 LED의 광출력과 수명에 매우 중요한 영향을 주는 인자로 알려져 있다. 본 연구에서는 가로등용 고출력 LED 패키지를 개발함에 있어서 효과적인 방열을 하기 위하여 방열효과가 상대적으로 우수한 구조인 chip-on-a-heat sink 구조를 가지는 세라믹-메탈 기반의 패키지를 제조하였다. 열확산 기능을 하는 heat sink 기판소재는 알루미늄 합금을, LED 어레이 회로를 형성하는 절연막으로는 저온동시소성용 glass-ceramics을 사용하였다. 특히 열처리 시 가장 이슈가 되는 세라믹-금속 하이브리드 패키지 기판의 휨을 억제하기 위한 수단으로서, glass-ceramic 절연막을 부분 코팅함으로써 휨현상을 용이하게 줄일 수 있게 되었다. 또한, LED 패키지의 방열특성의 향상 즉 열저항도 기존의 MCPCB 패키지나 전면 코팅형 절연막 패키지에 비해 훨씬 낮아지는 효과를 얻었을 뿐 아니라, 세라믹 코팅소재의 절감효과도 볼 수 있게 되었다.

• 한국재료학회지
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• 제13권12호
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• pp.769-774
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• 2003

In this paper, we report on the DC characteristics of the AlGaN/GaN HFETs using physical models on piezoelectric and thermal effects. Employing the models was found to be essential for a realistic prediction of the DC current-voltage characteristics of the AlGaN/GaN HFETs. Though use of the implementation of the physical models, peak drain current, transconductance, pinch-off voltage, and most importantly, the negative slope in the current were accurately predicted. The importance of the heat sink effect was demonstrated by the comparison of the DC characteristics of AlGaN/GaN HFETs fabricated from different substrates including sapphire, Si and SiC. Highest peak current was achieved from the device with SiC by an effective suppression of heat sink effect.

• Design & Manufacturing
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• 제10권3호
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• pp.14-19
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• 2016

Thermally or electrically conductive filler reinforced polymer composites are extensively being developed as the demand for light weight material increases rapidly in industiral applications need good conductivity such as heat sink of the electronics or light. Carbon or ceramic materials like graphite, carbon nanotube or boron nitride are typical conductive fillers with good thermal or electical conductivity. Using these conductive fillers, the polymer composites in the market show wide range of thermal conductivity from approximately 1 W/mK to 20 W/mK, which is quite enhanced considering the thermal conductivity lower than 0.5 W/mK for most polymeric materials. The practical use of these composites, however, is yet limited to specific applications because most composites are still not conductive enough or too difficult to process, too brittle, too expensive for higher conductivity. For practical use of conductive composite, the thermal conductivity required depending on the heat releasing mode are studied first for simplified unit cooling geometry to propose thermal conductivities of the composites for reasonable cooling performance comparing with the metal heat sink as a reference. Also, as a practical design for heat sink based on polymer composite, composite and metal sheet hybrid structures are investigated for LED lamp heat sink and audio amplication module housing to find that this hybrid structure can be a good solution considering all of the cooling performance, manufacturing, mechanical performance, cost and weight.

• 대한기계학회논문집B
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• 제26권8호
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• pp.1172-1182
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• 2002

In the present study a general criterion for local thermal equilibrium is presented in terms of parameters of engineering importance which include the Darcy number, the effective Prandtl number of fluid, and the Reynolds number. For this, an order of magnitude analysis is performed for the case when the effect of convection heat transfer is dominant in a porous structure. The criterion proposed in this study is more general than the previous criterion suggested by Carbonell and Whitaker, because the latter is applicable only when conduction is the dominant heat transfer mode in a porous medium while the former can be applied even when convection heat transfer prevails. In order to check the validity of the proposed criterion for local thermal equilibrium, the forced convection phenomena in a porous medium with a microchanneled structure subject to an impinging jet are studied using a similarity transformation. The proposed criterion is also validated with the existing experimental and numerical results for convection heat transfer in various porous materials that include some of the parameters used in the criterion such as a microchannel heat sink with a parallel flow, a packed bed, a cellular ceramic, and a sintered metal. It is shown that the criterion presented in this work well-predicts the validity of the assumption of local thermal equilibrium in a porous medium.

• 한국세라믹학회지
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• 제44권11호
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• pp.622-626
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• 2007

Graphite is widely used in electronic industry due to its excellent electrical and thermal properties. However, graphite starts to oxidize around $400^{\circ}C$ that seriously degrades its properties. SiC coating can be applied to graphite foam to improve its high temperature oxidation resistance. In this research, SiC coating on graphite foam was made via preceramic polymer using a polyphenylcarbosilane. 20% of polyphenylcarbosilane in hexane solution was coated onto graphite by dip coating method. Thermal oxidation was carried out at $200^{\circ}C$ for crosslink of the preceramic polymer and the sample were pyrolysized at $800^{\circ}C{\sim}1200^{\circ}C$ under nitrogen to convert the preceramic polymer to SiC film. The microstructure of the SiC coating after pyrolysis was investigated using FESEM and oxidation resistance up to $800^{\circ}C$ was evaluated.

• 한국산학기술학회논문지
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• 제18권7호
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• pp.17-25
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• 2017

최근에 LED나 OLED와 같은 조명용 소자의 온도 상승에 따른 문제점을 개선하기 위하여 전기 도금 방법을 사용하여 제작한 두께가 두꺼운 금속 필름을 heat sink로 사용하고 있다. Cu 필름과 같은 두꺼운 금속 필름은 습식 방법인 전기 도금으로 제작하여 주로 소자의 방열판으로 사용되어 왔으나 건식의 증착 방법을 이용한 수 백 ${\mu}m$의 Cu 금속 필름에 대한 필요성이 요구되고 있다. 본 연구에서 설계 제작된 유도 가열 방식의 Cu 필름 증착 장비는 가열부가 세라믹 도가니 히터 부분과 세라믹 도가니 부분으로 분리된 이중 구조의 heating 방식을 채택하여 열 손실을 최소화 하고 보온 효과를 극대화시켰다. 또한 유도 가열 방식으로 초고속의 필름 증착 속도를 구현하였다. 그리고 열전도도가 높고 안정적인 두꺼운 Cu 필름 증착기술을 확보하고 최적화 하여 $1000{\AA}/s$의 증착율로 $100{\mu}m$의 필름을 증착 하였으며 ~2.0% 이내의 두께 균일도를 얻었다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2012년도 춘계학술논문집 2부
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• pp.762-764
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• 2012

본 연구에서는 잉곳을 절삭하여 웨이퍼를 만들 때 발생하는 슬러리로부터 SiC를 분리하고, 이를 재생시켜 다공성 SiC 세라믹 히트싱크를 제작하였다. 또한 제작 된 다공성 SiC 세라믹 히트싱크의 열적물성치를 레이저 플래쉬 방법으로 측정하였고 알루미늄 히트싱크와의 비교실험을 통해 다공성 SiC 세라믹 히트싱크의 방열성능을 검증하였다.

• 대한기계학회논문집A
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• 제32권11호
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• pp.1016-1021
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• 2008

The development of the first wall whose major function is to withstand high neutron and heat fluxes is a critical path to fusion power. The materials database and the fabrication technology are being developed for design, construction and safety operation of the fusion reactor. The first wall was designed to consist of the plasma facing armor, the heat sink layer and the supporting plates. and Porous materials are of significant interest due to their wide applications in catalysis, separation, lightweight structural materials. In this study, the characteristics of the sintering process of SiC ceramic, $SiC_f$/SiC composite and porous $C_f$/SiC composite have been introduced order to study of the fusion blanket materials and heat-exchange pannel.