Light extraction analysis of high-power LED based on flip chip technology

The light extraction has an important effect on LED encapsulation to obtain a high efficiency. The influence of packaging structure on LED light extraction was investigated in TracePro. Four kinds of high-power LED packaging methods based on the structure and the character of flip chip were presented, flip chip on board (1 reflective-cup), flip chip to substrate (1 reflective-cup), flip chip on board (100 reflective-cups) and flip chip to substrate (100 reflective-cups). Flip chip on board was that the LED chip was directly bonded to the aluminum substrate, flip chip to substrate was the LED chip bonded to the Si-Substrate before bonded to the aluminum. Two different structures of aluminum substrate were analyzed, 1 substrate with only 1 reflective cup and 1 substrate with 100 reflective cups. The final result shows that the luminous efficiency of flip chip on board (100 reflective-cups) is 0.03% higher than flip chip to substrate (100 reflective-cups); luminous efficiency of flip chip on board (1 reflective-cup1) is 0.04% lower than flip chip to substrate(1 reflective-cup). Luminous efficiency of flip chip on board (100 reflective-cups) is 10% higher than flip chip on board(1 reflective-cups); luminous efficiency of flip chip to substrate (100 reflective-cups) is 6.3% higher than flip chip to substrate(1 reflective-cup).