This paper measures the LED thermal resistance characteristic by thermal transient tester (T3Ster) obtained the cumulative structure functions curve and differential structure functions curve. The actual K factor and optical power are obtained by testingⅠ. The thermal resistance characteristic of each layer for LED structure are analyzed by testingⅡ in different cases. The experimental results show that the bonding method and the heat sink size have tremendous influence on the LED thermal resistance’s reduce, and the contact thermal resistance takes up a great proportion in LED total thermal resistance. The contact thermal resistance may reduce by pressure on interface and by a change of the attach material and the roughness of interface.

Electronic package development is driven by the continuous increase in demands for miniaturization of products with enhanced performances. Three Dimensional System in Package (3D SiP) has become a key technology to satisfy the request. The 3D SiP with Through Silicon Via (TSV) technology is developed for chip to chip stacking in a package with superior electrical performance than conventional structures. In this study, we evaluate the thermal performance of 3D SiP with TSV technology using Finite Element Method (FEM). The evaluation topics covered impacts of various materials of mold, 3D SiP models with and without TSV, and various convention conditions. The results indicated that the role of TSVs in heat dissipation is not obvious in this study, and the maximum temperature merged in the center of the chip1 under different conditions which are considered.

Thermal contact resistance is one of key technologies for heat transfer of high power light emitting diodes (LED) packaging. In this paper, based on the resistance network model of LED packaging, a 3-D finite element simulation model (FEM) is established and thermal transient testing experiments are also performed by Thermal Transient tester (T3Ster). Experiment date indicates thermal contact resistance for 48% of the total thermal resistance. The thermal interface material (TIM) layer of high power LED packaging is studied to analysis thermal contact resistance which impacts on thermal performance of LED packaging. The total thermal resistance and the thermal resistance of TIM layer are separately calculated from simulation and experiment. To the resistance of TIM layer, the result of experiment is only a 1% error compared to the result of FEM simulation. Therefore, The FEM simulation and experiment are mutually validated. In order to thoroughly study on thermal contact resistance, based on the principle of structure function, thermal resistance of three different types of TIM layer between metal core printed circuit board (MCPCB) and aluminum heat sink are measured and compared. Experiment results indicate that the quality of interface affects the thermal contact resistance to a great extent.