• 전기전자학회논문지
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• 제22권1호
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• pp.193-196
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• 2018

In this study, we investigated the reliability of anisotropic conductive paste (ACP) and anisotropic conductive films (ACF), which are anisotropic conductive adhesives, applied to automotive touch panels. Adhesive material is also important as a key factor in assembling the touch panel. In order to measure the resistance change of the parts in two kinds of high temperature test, the reliability of the two types of anisotropic conductive adhesives was compared and evaluated through the results of the resistance change. For 615 hours of reliability testing, the anisotropic conductive film exhibited a higher stability in a high temperature environment than the anisotropic conductive paste.

• 마이크로전자및패키징학회지
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• 제12권1호
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• pp.9-16
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• 2005

This paper presents the development of new anisotropic conductive adhesives with enhanced thermal conductivity for the wide use of adhesive flip chip technology with improved reliability under high current density condition. The continuing downscaling of structural profiles and increase in inter-connection density in flip chip packaging using ACAs has given rise to reliability problem under high current density. In detail, as the bump size is reduced, the current density through bump is also increased. This increased current density also causes new failure mechanism such as interface degradation due to inter-metallic compound formation and adhesive swelling due to high current stressing, especially in high current density interconnection, in which high junction temperature enhances such failure mechanism. Therefore, it is necessary for the ACA to become thermal transfer medium to improve the lifetime of ACA flip chip joint under high current stressing condition. We developed thermally conductive ACA of 0.63 W/m$\cdot$K thermal conductivity using the formulation incorporating $5 {\mu}m$ Ni and $0.2{\mu}m$ SiC-filled epoxy-bated binder system to achieve acceptable viscosity, curing property, and other thermo-mechanical properties such as low CTE and high modulus. The current carrying capability of ACA flip chip joints was improved up to 6.7 A by use of thermally conductive ACA compared to conventional ACA. Electrical reliability of thermally conductive ACA flip chip joint under current stressing condition was also improved showing stable electrical conductivity of flip chip joints. The high current carrying capability and improved electrical reliability of thermally conductive ACA flip chip joint under current stressing test is mainly due to the effective heat dissipation by thermally conductive adhesive around Au stud bumps/ACA/PCB pads structure.

• 한국재료학회지
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• 제5권8호
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• pp.929-935
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• 1995

구동 IC를 유리기판 위의 Al패드 전극에 연결하는 LCD(Liquid Crystal Display) 모듈을 실장하는 Chip On Glass (COG) 기술을 개발하기 위하여 기존에 잘 알려진 기술 가운데 실제로 적용 가능성이 가장 유망한 이방성 도전 접착제 (ACA, Anisotropic Conductive Adhesives)를 사용한 공정에 대하여 조사하였다. ACA 공정은 본딩 부분에 ACA 수지를 균일하게 분포시키는 공정과 자외선을 조사하여 수지를 경화하여 칩을 실장하는 공정의 2단계로 진행하였다. 칩에 가해준 하중은 2-15kg이었고 칩의 예열 온도는 12$0^{\circ}C$이었다. 이방성 도전체는 Au 또는 Ni이 표면 피막 재료로 사용된 것을 사웅하였으며 전도성 입자의 갯수가 500, 1000, 2000, 4000개/$\textrm{mm}^2$이며 크기가 5, 7, 12$\mu\textrm{m}$이었다. ACA 처리의 결과 입자 크기가 5$\mu\textrm{m}$이고 입자 밀도는 4000개/$\textrm{mm}^2$일 경우가 대단히 낮은 접촉 저항 및 가장 안정된 본딩 특성을 나타냈었다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 International Symposium
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• pp.97-120
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• 2002

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2003년도 International Symposium
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• pp.123-144
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• 2003

• 마이크로전자및패키징학회지
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• 제16권2호
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• pp.1-9
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• 2009

Conductive adhesives have recently received a lot of focus and attention from the researchers in electronics industry as a potential substitute to lead-containing solders. Numerous studies have shown that the conductive adhesives have many advantages over conventional soldering such as environmental friendliness, finer pitch feasibility and lower temperature processing. This review focuses on the recent research trends on the reliability and property evaluation of anisotropic and non-conductive films that interconnect the integrated circuit component to the printed circuit board or other types of substrate. Major topics covered are the conduction mechanism in adhesive interconnects; mechanical reliability; thermo-mechanical-hygroscopic reliability and electrical performance of the adhesive joints. This review article is aimed at providing a better understanding of adhesive interconnects, their principles, performance and feasible applications.

• Journal of Welding and Joining
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• 제35권3호
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• pp.15-20
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• 2017

In this paper, two types of assemblies using CNT-filled SACAs (with 0.03 wt% CNTs and without CNT) were prepared to investigate the influence of carbon nanotubes (CNTs) on the reliability properties of solderable anisotropic conductive adhesives (SACAs) with a low-melting-point alloy (LMPA). Two types of reliability test including thermal shock (TS: -55 to $125^{\circ}C$, 1000 cycles) and high-temperature and high-humidity (HTHH: $85^{\circ}C$, 85% RH, 1000 h) tests were conducted. The SACA assemblies with and without CNTs showed stable electrical reliability properties due to the formation of wide and stable metallurgical interconnection between corresponding metallizations by the molten LMPA fillers. Although the mechanical pull strength of CNT-filled SACA assemblies was decreased after thermal aging (because of the excessive layer growth and planarization of the IMCs), the CNT-filled SACA with 0.03wt% CNTs showed enhanced mechanical reliability properties compared with the SACA assemblies no CNTs. This enhancement in mechanical performance was due to the reinforcement effect of the CNTs. These results demonstrate that CNTs within the CNT-filled SACAs can improve the reliability properties of CNT-filled SACAs joints due to their superior physical properties.

• Journal of Welding and Joining
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• 제26권1호
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• pp.44-49
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• 2008

• 반도체디스플레이기술학회지
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• 제15권4호
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• pp.10-15
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• 2016

In this paper, novel ball grid array (BGA) interconnection process using solderable anisotropic conductive adhesives (SACAs) with low-melting-point alloy (LMPA) fillers have been developed to enhance the processability in the conventional capillary underfill technique and to overcome the limitations in the no-flow underfill technique. To confirm the feasibility of the proposed technique, BGA interconnection test was performed using two types of SACA with different LMPA concentration (0 and 4 vol%). After the interconnection process, the interconnection characteristics such as morphology of conduction path and electrical properties of BGA assemblies were inspected and compared. The results indicated that BGA assemblies using SACA without LMPA fillers showed weak conduction path formation such as solder bump loss or short circuit formation because of the expansion of air bubbles within the interconnection area due to the relatively high reflow peak temperature. Meanwhile, assemblies using SACA with 4 vol% LMPAs showed stable metallurgical interconnection formation and electrical resistance due to the favorable selective wetting behavior of molten LMPAs for the solder bump and Cu metallization.

• 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.