• The Southeast Asian review
• /
• v.27 no.3
• /
• pp.93-135
• /
• 2017

Due to their geographic proximity to Beijing, the Southeast Asian states under the fallout of the China's growing power are struggling to seek the art of diplomacy to promote their national interests. This study explores why Cambodia previously taking a pro-US strategy after the end of the Cold War has switched to a pro-China one in the context of the rise of G-2 system, the ASEAN regionalism, the country's national interest and Hun Sen's regime legitimation. Theoretically, this study takes a realist constructivist approach and tries to find how realist interests and norms have affected the Hun Sen's regime legitimation. The relationship between China and Cambodia has been deepened by mutual economic interdependence and increasingly stronger Chinese power. Especially, the Chinese massive economic aids and investment have enormously supported the regime legitimation of Hun Sen. On the other hand, The US value diplomacy promoting democracy and human rights has undermined the Hun Sen's legitimacy and strained the two nations' relationship. However, the Hun Sen's pro-China strategy is not to check and balance against US strategic interests and not to recognize the Chinese hegemonic position in Southeast Asia. It is a hedging against the US value diplomacy while maximizing economic and other gains from China. ASEAN has been playing a coordinating role to limit the scope of power politics among big powers and to mitigate its ramifications. Yet, since the US and Chinese interests are so keenly criss-crossing, Cambodia may continue to react to the G-2 system through bilateral relations with them.

• Journal of the Microelectronics and Packaging Society
• /
• v.27 no.1
• /
• pp.55-65
• /
• 2020

The use of underfill materials in semiconductor packages is not only important for stress relieving of the package, but also for improving the reliability of the package during shock and vibration. However, in recent years, as the size of the package becomes larger and very thin, the use of the underfill shows adverse effects and rather deteriorates the reliability of the package. To resolve these issues, we developed the package using a solid epoxy material to improve the reliability of the package as a substitute for underfill material. The developed solid epoxy was applied to the package of the application processor in smart phone, and the reliability of the package was evaluated using thermal cycling reliability tests and numerical analysis. In order to find the optimal solid epoxy material and process conditions for improving the reliability, the effects of various factors on the reliability, such as the application number of solid epoxy, type of PCB pad, and different solid epoxy materials, were investigated. The reliability test results indicated that the package with solid epoxy exhibited higher reliability than that without solid epoxy. The application of solid epoxy at six locations showed higher reliability than that of solid epoxy at four locations indicating that the solid epoxy plays a role in relieving stress of the package, thereby improving the reliability of the package. For the different types of PCB pad, NSMD (non-solder mask defined) pad showed higher reliability than the SMD (solder mask defined) pad. This is because the application of the NSMD pad is more advantageous in terms of thermomechanical stress reliability because the solderpad bond area is larger. In addition, for the different solid epoxy materials with different thermal expansion coefficients, the reliability was more improved when solid epoxy having lower thermal expansion coefficient was used.