• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.667-670
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• 2005

본 논문은 100um와 80um의 텅스텐 와이어를 이용하여 세라믹(Ceramic)기판에 홀(Hole)을 뚫어 텅스텐 와이어를 수직으로 세우는 방식으로 수직형의 마이크로 스프링을 제작하였다. 마이크로 스프링의 설계를 위해 제한된 실험 결과와 신경회로망을 이용하여 텅스텐 와이어의 두께와 높이, 쉬프트(Shift)의 양을 변화시키면서 장력(Tension force)을 모델링하였고 제작을 통해 검증하였다. 이는 기존의 수평형 프로브카드의 한계를 대체할 수 있는 수직형 프로브카드의 핵심 모듈로서 멀티다이(Multi Die) 뿐만 아니라 범핑(Bumping)타입의 칩 테스트도 가능하다.

• Journal of the Korean Magnetics Society
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• v.17 no.3
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• pp.141-146
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• 2007

A new class of LC-resonator for micro magnetic sensor device was invented and fabricated by means of MEMS technique. The micro LC-resonator consists of a solenoidal micro-inductor with a bundle of soft magnetic microwire cores and a capacitor connected in parallel to the micro-inductor. The core magnetic material is a tiny glass coated $Co_{83.2}B_{3.3}Si_{5.9}Mn_{7.6}$ microwire fabricated by a glasscoated melt spinning technique. The core materials were annealed at various temperatures $150^{\circ}C,\;200^{\circ}C\;,250^{\circ}C\;,$ and $300^{\circ}C$ for 1 hour in a vacuum to improve soft magnetic properties. The solenoidal micro-inductors fabricated by MEMS technique were $500{\sim}1,000{\mu}m$ in length with $10{\sim}20$ turns. The changes of inductance as a function of external magnetic field in micro-inductors with properly annealed microwire cores were varied as much as 370%. Since the permeability of ultra soft magnetic microwire is changing rapidly as a function of external magnetic field. The inductance ratio as well as magnetoimpedance ratio (MIR) in a LC-resonator was varied drastically as a function of external magnetic field. The MIR curves can be tuned very precisely to obtain maximum sensitivity. A prototype magnetic sensor device consisting of the developed microinductors with a multivibrator circuit was test successfully.

• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.196-197
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• 2004

• Journal of the Microelectronics and Packaging Society
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• v.24 no.2
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• pp.29-35
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• 2017

In this paper, we investigated a manufacturing process of metal micro-wire interconnection on submillimeter diameter catheter. Over the years, flexible electronic researches have focused on flexible plane polymer substrate and micro electrode manufacturing on its surface. However, a curved polymer substrate, such as catheter, is very important for medical application. Among many catheters, importance of submillimeter diameter steerable catheter is increasing to resolve the several limitations of neurosurgery. Steering actuators have been researched for realizing the steerable catheter, but there is no research about practical wiring for driving these actuators. Therefore we developed a new manufacturing process for metal micro-wire interconnection on submillimeter diameter catheter. We designed custom jigs for alignment of the metal micro-wires on the submillimeter diameter catheter. An UV curing system and commercial products were used to reduce the manufacturing time and cost; Au micro-wire, UV curable epoxy, UV lamp, and submillimeter diameter catheter. The assembled catheter was characterized by using an optical microscope, a resistance meter, and a universal testing machine.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.4
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• pp.41-49
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• 2008

Thermoelectric properties of the n-type Bi-Te and the p-type Bi-Sb-Te films were measured and the growth behaviors of the electrodeposited Bi-Te and Bi-Sb-Te nanowires were characterized. Filling ratios of 81% and 77% were obtained for electrodeposition of the Bi-Te and the Bi-Sb-Te nanowires, respectively, into the nano pores of 200 nm-diameter of an alumina template. A thermoelectric module, composed of the Bi-Te nanowires and the Bi-Sb-Te nanowires was processed by electrodeposition, and a resistance value of $15{\Omega}$ was measured between the Ni electrodes formed on the Bi-Te nanowires and the Bi-Sb-Te nanowires of the module.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.1
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• pp.67-71
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• 2021

In this study, graphene layer was grown on metal microwire using chemical vapor deposition. The difference of carbon solubility between copper and nickel resulted in the formation of mono-layer and multi-layer graphene were formed on the surfaces of copper and nickel microwires, respectively. During the growth of graphene at high temperature, copper and nickel were recrytallized and the grain size increased. The ampacity of graphene/copper microwire was improved by approximately 27%, 1.91×105 A/㎠, compared to pristine copper microwire. Similar to this behavior, the ampacity of multilayer graphene/nickel microwire was 4.41×104 A/㎠ which is about about 36% improved compared to the pure nickel microwire. The excellent electrical properties of graphene/metal composites are beneficial for supplying the electrical energy to the high-power electronic devices and equipment.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.73-76
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• 2020

Silver nanowires (AgNWs) intrinsically possess high conductivity, ductility, and network structure percolated in a low density, which have led to many advanced applications of transparent and flexible electronics. Most of these applications require patterning of AgNWs, for which photolithographic and printing-based techniques have been widely used. However, several drawbacks such as high cost and complexity of the process disturb its practical application with patterning AgNWs. Herein, we propose a novel method for the patterning of AgNWs by employing UV-curable adhesive tape with a structure of liner/adhesive layer/polyolefin (PO) film and UV irradiation to simplify the process. First, the UV-curable adhesive tape was attached to AgNWs/polyurethane (PU), and then selectively exposed to UV irradiation by using a photomask. Subsequently, the UV-curable adhesive tape was peeled off and consequently AgNWs were patterned on PU substrate. This facile method is expected to be applicable to the fabrication of a variety of low-cost, shape-deformable transparent and wearable devices.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.103-111
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• 2017

In this study, the thermomechanical stress and fatigue analysis of a high voltage and high current (3,300 V/1200 A) insulated gate bipolar transistor (IGBT) module used for electric locomotive applications were performed under thermal cycling condition. Especially, the reliability of the copper wire and the ribbon wire were compared with that of the conventional aluminum wire. The copper wire showed three times higher stress than the aluminum wire. The ribbon type wire showed a higher stress than the circular type wire, and the copper ribbon wire showed the highest stress. The fatigue analysis results of the chip solder connecting the chip and the direct bond copper (DBC) indicated that the crack of the solder mainly occurred at the outer edge of the solder. In case of the circular wire, cracking of the solder occurred at 35,000 thermal cycles, and the crack area in the copper wire was larger than that of the aluminum wire. On the other hand, when the ribbon wire was used, the crack area was smaller than that of the circular wire. In case of the solder existing between DBC and base plate, the crack growth rate was similar regardless of the material and shape of the wire. However, cracking occurred earlier than chip solder, and more than half of the solder was failed at 40,000 cycles. Therefore, it is expected that the reliability of the solder between DBC and base plate would be worse than the chip solder.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.158-158
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• 2016

최근 유연정보전자소자의 개발이 대두되고 있다. 이러한 개발 동향에 맞춰 정보전자소자의 각 소재를 유연화하는 연구가 진행되고 있다. 이 중 ITO 기반의 기존 투명전극은 투명전극으로써는 매우 높은 성능을 보이지만, 유연성이 매우 낮기 때문에 대체 투명전극에 대한 연구가 필수적이다. 그래핀, 전도성 고분자, Oxide/metal/oxide, 금속나노와이어 등 다양한 유연 투명전극에 대한 연구가 진행되고 있으나 ITO 급의 면저항/투과도를 얻지 못하고 있다. 은나노와이어는 ITO 대체로 주목받는 투명전극 중에 면저항/투과도가 가장 ITO에 유사하면서, 유연성까지 지니고 있는 장점을 가지고 있다. 반면 약 100 nm 직경의 1차원 나노와이어가 랜덤하게 분포되어 있기 때문에, 위치별로 균일성에 대한 이슈가 존재하고, 표면 조도가 매우 높기 때문에 (ITO ~ 1 nm, AgNW > 20 nm) OLED에 적용하기 어려운 문제가 존재한다. 또한 대면적 OLED에 적용하기에는 여전히 저항이 높은 문제가 존재한다. 본 연구에서는 이러한 은나노와이어의 높은 저항 문제를 해결하기 위해, 마이크로 급의 미세금속배선을 보조배선으로 도입하였다. 이러한 보조배선을 통해 대면적 소자에도 전류가 잘 흐를 수 있고, 이러한 전류가 은 나노와이어를 통해 소자 전면적에 균일하게 도달하여, 대면적에서 균일한 발광을 하게 된다. 본 은나노와이어/금속보조배선 구조는 면저항 4 ohm/sqr., 투과도 90%를 달성하였고 이는 기존 ITO보다 우수한 수치이다. 더욱이, 유연성까지 함께 확보하고 있어 유연 전극으로써의 활용도 충분히 가능하다. 이를 활용해 OLED를 제작한 결과 밝기와 발광균일도가 기존의 ITO를 활용한 것보다 훨씬 높아짐을 확인할 수 있었다.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.502-503
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• 2000