Thermal transfer influence of delamination in the die attach layer of chip-on-board LED package base on entropy generation analysis

From the perspective of the irreversible energy loss of the second law of thermodynamics, that is entropy generation, theoretical analysis on the influence of delamination appeared at the die attach (DA) layer on the chip junction temperature of high power LED-COB package is carried out. First, thermal simulation of chip-on-board LED package with different position of interface delamination is investigated. The results show that delamination occurs at the edge position is more harmful for blocking heat transfer in the overall LED package than that of the center position. Second, entropy generation of edge position and center position in die attach layer with non-delamination is calculated. In the same conditions, the entropy generation value of the edge position is larger than that of the center position, that is, compared to center position, the larger irreversible heat flux loss in the edge position of die attach in the heat conduction process is higher.