• 대한전자공학회논문지SD
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• 제47권4호
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• pp.69-74
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• 2010

알루미늄 양극산화(aluminum anodization)의 선택적인 적용을 통하여 DRAM 소자를 위한 새로운 패키지 기판을 제작하였다. 에폭시 계열의 코어(core)와 구리의 적층 형태로 제작되는 일반적인 패키지 기판과는 달리 제안된 패키지 기판은 아래층 알루미늄(aluminum), 중간층 알루미나(alumina, $Al_2O_3$) 그리고 위층 구리(copper)로 구성된다. 알루미늄 기판에 양극산화 공정을 수행함으로써 두꺼운 알루미나를 얻을 수 있으며 이를 패키지 기판의 유전체로 사용할 수 있다. 알루미나층 위에 구리 패턴을 배치함으로써 새로운 2층 금속 구조의 패키지 기판을 완성하게 된다. 또한 알루미늄 양극산화를 선택적인 영역에만 적용하여 내부가 완전히 채워져 있는 비아(via) 구조를 구현할 수 있다. 패키지 설계 시에 비아 인 패드(via in pad) 구조를 적용하여 본딩 패드(bonding pad) 및 볼 패드(ball pad) 상에 비아를 배치하였다. 상기 비아 인 패드 배치 및 2층 금속 구조로 인해 패키지 기판의 배선 설계가 보다 수월해지고 설계 자유도가 향상된다. 새로운 패키지 기판의 주요 설계인자를 분석하고 최적화하기 위하여 테스트 패턴의 2차원 전자기장 시뮬레이션 및 S-파라미터 측정을 진행하였다. 이러한 설계인자를 바탕으로 모든 신호 배선은 우수한 신호 전송을 얻기 위해서 $50{\Omega}$의 특성 임피던스를 가지는 coplanar waveguide(CPW) 및 microstrip 기반의 전송선 구조로 설계되었다. 본 논문에서는 패키지 기판 구조, 설계 방식, 제작 공정 및 측정 등을 포함하여 양극산화 알루미늄 패키지 기판의 특성과 성능을 분석하였다.

• 마이크로전자및패키징학회지
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• 제7권3호
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• pp.37-44
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• 2000

Electrochemical impedance spectroscopy (EIS)를 이용하여 에폭시 수지 조성물이 코팅된 알루미늄 패드의 부식거동을 연구하였다. 에폭시 수지 조성물은 반도체 패키지 봉지용으로써 80 wt%의 충전재를 포함하고 있으며, $100^{\circ}C$의 끊는 가혹 조건에서 탈이온수 (deionized water)를 사용하여 에폭시 조성들에 침투시켰다. 흡습이 진행되면서 에폭시 조성물 및 알루미늄/에폭시 계면에서의 저항 감소와 커패시턴스 증가가 관찰되었으며 , 약 170 시간까지는 물분자와 유기물로부터 발생된 이온이 에폭시 조성물에 포화되고, 그 이후에는 계면에 침투하여 금속의 부식을 발생시키는 것을 알 수 있었다. 수분 흡습에 따른 에폭시 조성물/금속간의 접착강도 측정으로부터 계면에 물분자 및 이온이 포화됨에 따라 접착강도가 감소하는 것을 예상할 수 있었으며, 반도체 패키지용 에폭시 수지 조성물에 의한 알루미늄 전극의 부식을 방지하기 위해서는 충전재의 함량증가가 필수적이라는 것을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제11권12호
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• pp.1079-1083
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• 1998

In this study, ultrasonic power of Aluminum wire bonder, bond time and bond force are investigated and valued in order to minimize failure of bonding pad lift. We also tried to control those 3 factors properly. We got the conclusion that if we turn down the ability of ultrasonic power or bond time, we can get a pad lift from a boundary between bond pad ad wire because pad metal and wire joining is unstable, but it is best condition when it ultrasonic power is 100∼130unit, bond time is 15∼20msec and bond force is 4∼6gf.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.411-412
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• 2007

• Tribology and Lubricants
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• 제27권2호
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• pp.95-100
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• 2011

The brake disc materials for railway vehicle have been mainly used cast-iron. The brake disc and pad should be light, resist to a thermal crack and absorb enough friction energy. In order to satisfy this requirement, aluminum alloy brake disc for railway vehicle has been newly developed. The aluminum itself has not been considered the friction material for railway vehicle. However, in the case of aluminum composite with dispersed ceramic particles, friction characteristics, resistance to wear and heat are much improved. In the present study, aluminum composite brake disc of 20% ceramic particle and three kinds of organic pads have been tested in dynamometer. The results show that Al MMC brake disc and pad have good friction coefficient and wear rate, and thermal cracks in brake disc have not been initiated. Also, the Al MMC brake disc can be applied to railway vehicle of 150 km/h.

• 대한기계학회논문집A
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• 제31권2호
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• pp.197-204
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• 2007

Fretting is a contact damage process that occurs between two contact surfaces. Fretting fatigue reduces fatigue strength of the material due to low amplitude oscillatory sliding and changes in the contact surfaces of strongly connected machine and structure such as bolt, key, pin, fixed rivet and connected shaft, which have relative slip of repeatedly extreme low frequency amplitude. In this research, the fretting fatigue behavior of 2024-T3511 and 7050-T7451 aluminum alloys used mainly in aircraft and automobile industry were experimentally estimated. Based on this experimental wort the following results were obtained: (1) A significant decrease of fatigue lift was observed in the fretting fatigue compared to the plain fatigue. The fatigue limit of 2024-T3511 aluminum alloy decreased about 59% while 7050-T7451 aluminum alloy decreased about 75%. (2) In 7050-T7451 specimen using ATSI4030 contact pad, crack was initiated more early stage than using 2024-T3511 contact pad. (3) In all specimens, oblique cracks were initiated at contact edge. (4) Tire tracks and rubbed scars were observed in the oblique crack region of fracture surface.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 추계 기술심포지움 논문집
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• pp.43-46
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• 2000

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2101-2106
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• 2011

It is reported that about more than 45% of damage shown in railroad rails include breakage of rail end which cross the center of Thermit welded zone. Thermite welding is always accompanied by numerous aluminum oxide and secondary inclusions, which may have a negative influence on the ductility and toughness of the weld metal. In this study the aluminum powder recycled by waste aluminum can was used for iron oxide generated after the process of welding rod and the remain aluminum was reduced by minimizing the quantity of aluminum. And complete dissolution was induced by using ferro Mn powder as the additive element. This study reviewed the applicability of heat treatment in the welded zone of rail using ceramic heating pad by carrying it out. This study could observe the improvement of the mechanical characteristics (UTS and elongation) and the changes of failure mechanism from brittleness to ductility. It could be found that improved strength and elongation result from pearilte fine structure.

• 소성∙가공
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• 제12권6호
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• pp.582-587
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• 2003

This paper is concerned with the mechanical property changes of the milli-size products manufactured by forward extrusion processes with square dies. Experiments are carried out with pure aluminum and pure copper billets. Extrusion ratio and knock-out pad are chosen as the important process parameters affecting the changes of mechanical properties such as shear strength and hardness. Shear strength tests with the extruded milli-size pin have shown the strong relation between victors hardness and shear strength in the neck of a stepped pin. As the extrusion ratio increases, the hardness on both the surface and the center line of a pin also increase. It is also noted that the hardness on the surface is a little higher than that on the center. The existence of knock-out pad in extrusion die causes the hardness in the neck of a extruded pin to increase. Finally, the approximated linear relations between shear strength and hardness of a pin are suggested.

• 한국산업융합학회 논문집
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• 제20권3호
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• pp.221-232
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• 2017

In this study, bipolar plates in fuel cells are formed using rubber forming process. The effects of important parameters in rubber forming such as hardness and thickness of rubber pad, speed and pressure of punch that compress blank, and physical property of materials on the channel depth were analyzed. In the soft material sheet Al1050, deeper channels are formed than in materials STS304 and Ti-G5. Formed channel depth was increased when hardness of rubber pad was lower, thickness of rubber pad was high, and speed and pressure of punch were high. It was found the deepest channel was achieved when forming process condition was set with punch speed and pressure at 30 mm/s and 55 MPa, respectively using rubber pad having hardness Shore A 20 and thickness 60 mm. The channel depths of bipolar plates formed with Al1050, STS304 and Ti-G5 under the above process condition were 0.453, 0.307, and 0.270 mm, respectively. There were no defects such as wrinkle, distortion, and crack found from formed bipolar plates.