Reliability potential of silicone molding compounds for LED application

As the development of light emitting devices (LEDs), integrate circuits (ICs) and concentration photovoltaic (CPV) modules towards higher density, packaging materials are facing the challenges of withstand with heat generation and high energy. Epoxy molding compound (EMC) is the latest technology for LED and solar cell package to replace PPA and PCT. However, it is well known that the thermal and radiation resistance of epoxy is limited. Recently, silicone based composites are attracting attention as ideal materials because they are insensible to high energy density and good resistance to UV light and heat. Epoxy and silicone both have reliability issues during long-term service at high temperature and high energy. Thermal and radiation degradation of reflector materials will largely affect their reflectance and their contribution to a higher light output and energy efficiency. Therefore, it is very essential to evaluate reliability performance of SMC and EMC based reflecting materials. Aging under multiple environmental conditions has generated considerable interest for evaluating the life and behavior of materials in a real environment. Radiation and thermal aging are two quite different types of aging. The combination of these two situations will cause the aging process to accelerate further. The objective of this study is to investigate the synergetic influence of thermal and radiation aging on optical performance of SMC and EMC based packaging materials. It is concluded that SMC is the preferred choice for packaging LEDs, ICs and solar cells for its superior thermal and radiation resistance.