The thermal evaluation of the substrate mixed with microencapsulated phase change materials for MEMS packaging applications

摘要

The thermal management of microelectronics has become a critical issue in Microsystems and optoelectronic industries. This is particularly evident with the development of high power density and high heat flux in MEMS, IC, and LED components and devices, which has further increased the demand for materials with high thermal performance. To enhance the performance of current thermal modules, the development of advanced materials to replace conventional monolithic materials is crucial. The energy storage characteristics exhibited by materials during phase change helps them to maintain a constant temperature and conserve energy. Microencapsulation is the technique of enclosing phase change materials within a high polymer shell to form microcapsules, called microencapsulated phase change materials (MPCMs). Mixing MPCMs into matrix materials makes it possible to control the temperature of systems. This study evaluates the thermal performance of an MPCM (manufactured as powder with 10-30 μm size) mixed substrate, and results show that the manufacturing process does not destroy the structure of MPCM. The time required for a substrate mixed with MPCM to reach thermal steady state was delayed, compared to the time required for substrates without MPCM. The higher the percentage of MPCM, the longer it took to reach steady state. In addition, the heat transfer efficiency of the MPCM in its solid state was lower than in its liquid state. This heat transfer behavior was quite different from that found in bulk-size materials. These results suggest the application of MPCM for the thermal control of microelectronics, thermal management of modern Microsystems technologies, and the conservation of green house energy.