• Polymer(Korea)
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• v.34 no.3
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• pp.191-197
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• 2010

To improve the curing method of anisotropic conductive film (ACF) at low temperature, it was studied to replace the thermal latent curing agent of imidazole compounds by the curing agent of cationically initiating type. Thermo-mechanical properties such as glass transition temperature, storage modulus, and coefficient of thermal expansion were investigated for the analysis of curing behavior. The reliability of ACF were observed in thermal cycle and high temperature-high humidity test. ACF using cationic initiator showed faster curing, lower CTE, and higher $T_g$ than the case of using imidazole curing agent, which is important for the high temperature stability. Furthermore, ACF using cationic initiator maintained a stable contact resistance in reliability test, although it was cured at low temperature and fast rate. With these results, it was confirmed that the curing method of epoxy had great effect on thermo-mechanical properties and reliability of ACF.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.1
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• pp.37-43
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• 2020

The effects of O₂ plasma pre-treatment and post-annealing conditions on the interfacial adhesion of Ti thin film and WPR dielectric were investigated using 90° peel test for fan-out wafer level packaging (FOWLP) redistribution layer (RDL) applications. Peel strength between Ti film and WPR dielectric decreased from 8.9±1.3 g/mm to 2.7±0.9 g/mm for variation of O₂ plasma pre-treatment time from 30s to 300s, which is closely related to C-O-C or C=O bonds breakage at the WPR dielectric surface due to excessive plasma pre-treatment conditions. During post-annealing at 150℃, the peel strength abruptly decreased from 0 h to 24 h, and then maintained constant until 100 h, which is also mainly due to the damage of WPR dielectric which is weak to high temperature. Therefore, the optimum plasma pre-treatment conditions on the surface of dielectric is essential to interfacial reliability of FOWLP RDL.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.12
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• pp.1023-1027
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• 2009

Cadmium sulfide (CdS) thin film for flexible optical device applications were prepared at $H_2/(Ar+H_2)$ flow ratios on polyethersulfon (PES) flexible polymer substrates at room temperature by radio frequency magnetron sputtering technique. The CdS thin films deposited at room temperature showed a (002) preferred orientation and the smooth surface morphologies. Films deposited at a hydrogen flow ratio of 25% exhibited a photo- and dark-sheet resistance of about 50 and $2.7\;{\times}\;10^5\;{\Omega}/square$, respectively. From the result of the bending test, CdS films exhibit a strong adhesion with the PES polymer substrates and the $Al_2O_3$ passivation layer deposited on the CdS films only shows an increase of the resistance of 8.4% after exposure for 120 h in air atmosphere.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1462-1465
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• 2005

In this report, the FE characteristics of carbon nanotubes (CNTs) treated using both thermal annealing and mechanical coatings on the as-grown CNTs system atically studied. It was found that in the high temperature annealed samples, CNTs were attacked at its root during annealing due to a small amount of oxygen, and were pulled out of the substrate in places after FE measurements because of the contact resistance. However, for the mechanically coated samples both with spin on glass (SOG) and polymethyl methacrylate (PMMA), CNTs were found to be nearly intact after FE measurements and showed reliable FE characteristics over repeatable voltage scan. The reliability of CNTs during FE could be owing to the strong adhesion of CNTs to the substrate both by SOG and PMMA coatings.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.26-26
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• 2010

Cadmium sulfide (CdS) thin film for flexible optical device applications were prepared at $H_2(Ar+H_2)$ flow ratios on polyethersulfon(PES) flexible polymer substrates at room temperature by radio frequency magnetron sputtering technique. The CdS thin films deposited at room temperature showed a (002) preferred orientation and the smooth surface morphologies. Films deposited at a hydrogen flow ratio of 25% exhibited a photo- and dark-sheet resistance of about 50 and $2.7{\times}10^5{\Omega}$/square, respectively. From the result of the bending test, CdS films exhibit a strong adhesion with the PES polymer substrates and the $Al_2O_3$ passivation layer deposited on the CdS films only shows an increase of the resistance of 8.4% after exposure for 120 h in air atmosphere.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1161-1170
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• 2014

Delta sash is an important part of automobile door, which has the functions of supporting and guiding seesaw of car's window, preventing dust and air from outside. In previous manufacturing process, each part of the delta sash was independently formed by tandem processes, and rubber is bonded to steel by poisonous glue. So, the previous processes, including roll forming process and toxic gases, had low production rate and high failure rate. In this study, progressive process design of the delta sash was proposed in order to increase productivity and high utilization of the materials. And instead of the poisonous glue used for adhesion of rubber in the previous tandem process, embossing and piercing processes were designed in the new guide to help the rubber to adhere well to steel. And the optimal piercing distance was designed to ensure structural safety, and prototypes were manufactured for verifying reliability of the processes.

• Korean Journal of Materials Research
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• v.20 no.12
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• pp.681-685
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• 2010

The application of flip chip technology has been growing with the trend of miniaturization of electronic packages, especially in mobile electronics. Currently, several types of adhesive are used for flip chip bonding and these adhesives require some special properties; they must be solvent-free and fast curing and must ensure joint reliability against thermal fatigue and humidity. In this study, imidazole and its derivatives were added as curing catalysts to epoxy resin and their effects on the adhesive properties were investigated. Non-isothermal DSC analyses showed that the curing temperatures and the heat of reaction were dependent primarily on the type of catalyst. Isothermal dielectric analyses showed that the curing time was dependent on the amount of catalysts added as well as their type. The die shear strength increased with the increase of catalyst content while the Tg decreased. From this study, imidazole catalysts with low molecular weight are expected to be beneficial for snap curing and high adhesion strength for flip chip bonding applications.

• Korean Journal of Materials Research
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• v.8 no.5
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• pp.399-407
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• 1998

본 연구에서는 LCD패키지용 이방성 전도 필름의 전기적, 기계적 특성 및 신뢰성에 미치는 접속 변수의 영향을 연구하였다. 이방성 전도 필름을 통한 전기적 전도 현상을 각각의 도전 입자와 기판 사이의 기계적 접촉에 의해 접촉 방향으로만 전류가 흐르게 되는 것이 주되는 전도 기구이다. 따라서 접속 압력에 따라 각각의 도전 입자의 변형으로 기판 사이의 접촉 면적이 변하는데 이방성 전도필름의 접촉 저항은 이런 접촉 변화에 의해 결정된다. 접속 압력에 따라 초기에 접촉 저항은 감소하다가 점차 접촉 저항기가 안정화되는 거동을 보였다. 그러나 높은 접속 압력에서는 오히려 저항치가 약간 증가함을 보였다. 이방성 전도 필름 접속의 접착력을 평가하기 위해 필 테스트(peel test)를 시행하였는데, 접속 압력과 접속 온도를 증가 시킬수록 이방성 전도 필름 접속의 접착력을 평가하기 위해 고온 시효 시험, 온도 사이클링 시험, 고온 고습 시험의 신뢰성 시험을 시행하였으며, 이중 고온 고습 시험이 ACF접속의 전기적, 기계적 특성에 가장 악영향을 주었다. 또 큰 압력으로 접속된 것보다 작은 압력으로 접속되었을 때, 그리고 도전입자로는 금속 코팅 된 폴리머 입자가 사용될 때 신뢰성이 상대적으로 좋은 것을 발견했다.

• Journal of Electrochemical Science and Technology
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• v.9 no.1
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• pp.9-19
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• 2018

The anodic behavior of aluminum (Al) foils with varying purity, capacitance, and withstand voltage in organic electrolytes was examined for EDLC. The results of cyclic voltammetry (CV) and chronoamperometry (CA) experiments showed that the electrochemical stability improves when Al foil has higher purity, lower capacitance, and higher withstand voltage. To improve the electrochemical stability of EDLC current collectors made of low-purity foil (99.4% Al foil), the foil was modified by chemical etching to reduce its capacitance to $60{\mu}F/cm^2$ and forming to have withstand a voltage of 3 Vf. EDLC cells using the modified Al foil as a current collector were made to 2.7 V with 360 F, and a constant voltage load test was subsequently performed for 2500 hours at high temperature under a rated voltage of 2.7 V. The reliability and stability of the EDLC cell improved when the modified Al foil was used as a current collector. To understand the deterioration process of the Al current collector, standard cells made of conventional Al foil under a constant voltage load test were disassembled, and the surface changes of the foil were measured every 500 hours. The Al foil became increasingly corroded, causing the adhesion between the AC coating layer and the Al foil to weaken, and it was confirmed that partial AC coating layer peeling occurred.

• Journal of the Korea Institute of Building Construction
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• v.4 no.1
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• pp.141-146
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• 2004

1) As a result of compressive strength experiment, rupture compressive strength showed more increases in specimens of 15% and 20% of Cockle shells in those of non-mixture. Comparing compressive strength between no-mixed Specimens and Specimens of containing Cockle shells, Specimens containing Cockle shells showed higher strength in 60 days and 90 days of age, and as ark Cockle is contained and age is elapsed, compressive strength is also increased In addition, estimation of compressive strength by reactive hardness in concrete using Cockle shells as aggregate shows low reliability. 2) As a result of experimenting compressive strength after heating, Specimens containing Cockle shells and non-mixed Specimens showed similar strength at $200^{\circ}C$, but compressive strength was lowered as content of Cockle shells increased at over $400^{\circ}C$ and heating temperature was higher. It is because Cockle shells was fired by heat and then its adhesion and bonding capacity were lost. 3) To sum up the above experimental results, it is found that using splitted Cockle shells as aggregate for concrete by 10%~20% showed the same or higher compressive strength and shear strength as concretes using general aggregate and it can be used as substitute aggregate of concrete. It is considered that for future use of splitted Cockle shells as substitute concrete aggregate, continuous researches of its durability, applicability and economy are needed.