• 한국정밀공학회지
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• 제17권2호
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• pp.130-136
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• 2000

Generally, the build-up printed circuit board manufactured by the sequential process with etching, plating, drilling etc. requires many types of equipments and lead time. Etching process is suitable for mass production, however, it is not adequate for manufacturing prototype in the developing stage. In this study, we introduce a screen printing technology to prototyping a build-up printed circuit board. As for the material, photo/thermal curable resin and conductive paste are used for the formation of dielectric and conductor. The build-up structure is made by subsequent processes such as the formation of liquid resin thin layer, the solidification by UV/IR light, and via filling with conductive paste. By use of photo curable resin, productivity is greatly enhanced compared with thermal curable resin. Finally, the basic concept and the possibility of build-up printed circuit board prototyping are proposed in comparison with to the conventional process.

• 한국정밀공학회지
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• 제24권5호
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• pp.89-96
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• 2007

Inkjet printing has become one of the most attractive manufacturing techniques in industry. Especially inkjet printing technology will soon be part of the PCB (Printed Circuit Board) fabrication processes. Traditional printing on PCB includes screen printing and photolithography. These technologies involve high costs, time-consuming procedures and several process steps. However, by inkjet technology manufacturing time and production costs can be reduced, and procedures can be more efficient. PCB manufacturers therefore willingly accept this inkjet technology to the PCB industry, and are quickly shifting from conventional to inkjet printing. To produce the printed circuit board by the inkjet technology, it must be harmonized with conductive nano ink, printing process, system, and inkjet printhead. In this study, micro patterning of conductive line has been investigated using the piezoelectric printhead driven by a bipolar voltage signal is used to dispense 20-40 ${\mu}m$ diameter droplets and silver nano ink which consists of 1 to 50 nm silver particles that are homogeneously suspended in an organic carrier. To fabricate a conductive line used in PCB with high precision, a printed line width was calculated and compared with printing results.

• International Journal of Precision Engineering and Manufacturing
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• 제4권4호
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• pp.51-56
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• 2003

Generally, the build-up printed circuit board manufactured by a sequential process involving etching, plating, drilling, etc, which requires many types of equipments and long lead time. Etching process is suitable for mass production, however, it is not adequate for manufacturing a prototype in the development stage. In this study, we introduce a screen printing technology for prototyping a build-up printed circuit board. As for the material, photo/thermal curable resin and conductive paste are used for the formation of dielectric and conductor. The build-up structure is made by subsequent processes such as formation of a liquid resin thin layer, solidification by a UV/IR light, and via hole filling with a conductive paste. By use of photo curable resin, productivity is greatly enhanced compared with thermal curable resin. Finally, the basic concept and the possibility of build-up printed circuit board prototyping are proposed in comparison with the conventional process.

• 마이크로전자및패키징학회지
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• 제6권4호
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• pp.15-22
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• 1999

일반적으로 빌드업 다층 인쇄회로기판은 에칭, 도금등의 습식공정에 의해 제작이 이루어지므로 많은 장비와 많은 시간이 필요하게 된다. 이러한 습식공정은 양산에는 적합하지만 개발단계에서는 그리 적합하지 않은 방법이다. 본 연구에서는 스크린 인쇄기술을 도입하여 빌드업 다층 인쇄회로기판을 제작하여 보았다. 절연성 재료로는 광경화성수지 또는 열경화성수지를 사용하였으며 전도성 재료로는 전도성 페이스트를 사용하였다. 층간의 전기적 연결을 담당하는 비아와 회로를 형성하기 위해 스크린 인쇄공정을 통해 전도성 페이스트를 인쇄 하였다. 이러한 방법을 통해 제품의 개발 단계에서 기존의 빌드업 다층 인쇄회로기판 제작 공정과 비교하여 좀더 효율적인 방법을 제시하였다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2004년도 추계 기술심포지움 초록집
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• pp.5-5
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• 2004

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.387-388
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• 2010

• 마이크로전자및패키징학회지
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• 제6권2호
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• pp.13-21
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• 1999

Flip chip assembly directly on organic boards offers miniaturization of package size as well as reduction in interconnection distances resulting in a high performance and cost-competitive Packaging method. This paper describes the investigation of alternative low cost flip-chip mounting processes using electroless Ni/Au bump and anisotropic conductive adhesives/films as an interconnection material on organic boards such as FR-4. As bumps for flip chip, electroless Ni/Au plating was performed and characterized in mechanical and metallurgical point of view. Effect of annealing on Ni bump characteristics informed that the formation of crystalline nickel with $Ni_3$P precipitation above $300^{\circ}C$ causes an increase of hardness and an increase of the intrinsic stress resulting in a reliability limitation. As an interconnection material, modified ACFs composed of nickel conductive fillers for electrical conductor and non-conductive inorganic fillers for modification of film properties such as coefficient of thermal expansion(CTE) and tensile strength were formulated for improved electrical and mechanical properties of ACF interconnection. The thermal fatigue life of ACA/F flip chip on organic board limited by the thermal expansion mismatch between the chip and the board could be increased by a modified ACA/F. Three ACF materials with different CTE values were prepared and bonded between Si chip and FR-4 board for the thermal strain measurement using moire interferometry. The thermal strain of ACF interconnection layer induced by temperature excursion of $80^{\circ}C$ was decreased with decreasing CTEs of ACF materials.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2001-2008
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• 2015

This paper proposes the concept of FlexPCB(flexible Printed Circuit Board) conductive structure for electrodynamic bearings. It has three main advantages: easy “printing” of considerably thin conductive wires, resulting in potential reduction in stray eddy currents; realization of specific conductive configurations with high precision to optimize the eddy current flowing; simplicity in being wound to cylinders or hollow cylinders of different diameters. To verify this new concept, the FlexPCB conductive structure was manufactured, an axial electrodynamic bearing test rig was built and the conductive structure's induced voltage was measured along the axial displacements from 0mm to 56mm at three rotating speeds. The finite element method was used to calcuatlate the flux density of electrodynamic bearing and induced voltage of the FlexPCB conductive structure. The experimental results are compared with the results from the FEM calculation. It is concluded that the measured and calculated induced voltages have consistency in the middle part of the bearing.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.619-620
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• 2011

• 마이크로전자및패키징학회지
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• 제16권3호
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• pp.25-29
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• 2009

COB(chip-on-board) 플립칩 패키지에 있어서 NCP(non-conductive paste)의 적용성을 확보하기 위해 자체 포뮬레이션한 NCP와 상용 NCP에 대하여 보드레벨 플립칩 패키지를 제작하고 고온고습 및 열충격 신뢰성을 평가하였다. 실험결과 보다 작은 입도의 용융 실리카를 첨가한 NCP 시제품들이 고온고습 신뢰성에 유리한 것을 알 수 있었다. 또한, NCP 접속부에 있어서 열응력에 의한 피로보다 흡습에 의한 에폭시의 팽창이 접속부 파손에 보다큰 영향을 미치는 것으로 나타났으며, NCP의 접착강도가 높을수록 NCP 플립칩 패키지의 열충격 신뢰성이 향상되는 것을 알 수 있었다.