In the aerospace field, Carbon/Cork composites have been used for rocket propulsion systems as a light weight structural component with a high bending stiffness and high thermal insulation properties. For the fabrication of a carbon composite with a heat insulation cork part, the bonding properties between them are very important to determine the service life of the Carbon/Cork composite structure. In this study, the changes in the interfacial adhesion and mechanical properties of Carbon/Cork composites under accelerated aging conditions were investigated. The accelerated aging experiments were performed with different temperatures and humidity conditions. The properties of the aged Carbon/Cork composites were evaluated mainly with the interfacial strength. Finally, the lifetime prediction of the Carbon/Cork composites was performed with the long-term property data under accelerated conditions.

Carbon blacks (CBs) have been widely used as reinforcing materials in advanced rubber composites. The mechanical properties of CB-reinforced rubber composites are mostly controlled by the extent of interfacial adhesion between the CBs and the rubber. Surface treatments are generally performed on CBs to introduce chemical functional groups on its surface. In this study, we review the effects of various surface treatment methods for CBs. In addition, the preparation and properties of CB-reinforced rubber composites are discussed.

3-D IC integration enables the smallest form factor and highest performance due to the shortest and most plentiful interconnects between chips. Direct metal bonding has several advantages over the solder-based bonding, including lower electrical resistivity, better electromigration resistance and more reduced interconnect RC delay, while high process temperature is one of the major bottlenecks of metal direct bonding because it can negatively influence device reliability and manufacturing yield. We performed quantitative analyses of the interfacial properties of Al-Al bonds with varying process parameters, bonding temperature, bonding time, and bonding environment. A 4-point bending method was used to measure the interfacial adhesion energy. The quantitative interfacial adhesion energy measured by a 4-point bending test shows 1.33, 2.25, and 6.44 J/m2 for 400, 450, and 500˚C, respectively, in a N2 atmosphere. Increasing the bonding time from 1 to 4 hrs enhanced the interfacial fracture toughness while the effects of forming gas were negligible, which were correlated to the bonding interface analysis results. XPS depth analysis results on the delaminated interfaces showed that the relative area fraction of aluminum oxide to the pure aluminum phase near the bonding surfaces match well the variations of interfacial adhesion energies with bonding process conditions.

The effect of annealing treatment conditions on the interfacial adhesion energy between electrolessplated Ni film and polyimide substrate was evaluated using a 180˚ peel test. Measured peel strength values are 26.9±0.8, 22.4±0.8, 21.9±1.5, 23.1±1.3, 16.1±2.0 and 14.3±1.3g/mm for annealing treatment times during 0, 1, 3, 5, 10, and 20 hours, respectively, at 200˚C in ambient environment. XPS and AES analysis results on peeled surfaces clearly reveal that the peeling occurs cohesively inside polyimide. This implies a degradation of polyimide structure due to oxygen diffusion through interface between Ni and polyimide, which is also closely related to the decrease in the interfacial adhesion energy due to thermal treatment in ambient conditions.

1.5 μm-thick copper films deposited on silicon wafers were successfully bonded at 415˚C/25 kN for 40 minutes in a thermo-compression bonding method that did not involve a pre-cleaning or pre-annealing process. The original copper bonding interface disappeared and showed a homogeneous microstructure with few voids at the original bonding interface. Quantitative interfacial adhesion energies were greater than 10.4 J/m2 as measured via a four-point bending test. Post-bonding annealing at a temperature that was less than 300˚C had only a slight effect on the bonding energy, whereas an oxygen environment significantly deteriorated the bonding energy over 400˚C. This was most likely due to the fast growth of brittle interfacial oxides. Therefore, the annealing environment and temperature conditions greatly affect the interfacial bonding energy and reliability in Cu-Cu bonded wafer stacks.

본 연구에서 FPC에 사용되는 동박과 접착제의 이종 재료간에 계면접착력을 향상시키기 위해 silane primer를 도입하였다. 또한 동박표면 및 에폭시 접착제를 개질하여 개질조건이 접착강도에 미치는 영향도 조사하였다. 본 실험은 접착제층과의 상용성을 고려하여 silane primer로 triethoxyvinylsilane을 용액 및 무유화제 유화중합한 고분자형태와 3-aminopropyl-triethoxysilane (3-APTES), 3-glycidoxypropylmethoxysilane (3-GPTMS)을 사용하여 접착제층과의 접착력 증진을 도모하였다. 동박표면은 1,1,1-trichloroethane을 사용하여 개질 시간에 따른 동박 표면의 지형변화와 그에 따른 접착강도를 조사하였다. 결과에 따르면 silane을 사용한 경우 동박-접착제간의 접착력이 약2 ~ 5배 정도 증진되었고, 동박표면의 개질시간은 약 10분 정도가 최적의 접착조건임을 알 수 있었다. 또한 저분자량 실란의 농도에 따른 접착력은 3-APTES는 약 0.5 vol.%에서 최고 접착력을 보였고, 3-GPTMS의 경우 약 0.2 vol.%에서 최고의 접착력을 보였다.