The Effects of Si Submounts Containing Cu Thermal Vias on the Heat-Dissipation Characteristics of a High-Power Light-Emitting Diode Package

Abstract

We investigated the effects of Si submounts containing Cu thermal vias on the heat-dissipation characteristics of a high-power light-emitting diode (LED) package. Simulations were used to determine the optimum conditions for effective heat dissipation from the LED. The optimum thickness of the Si submount containing the Cu thermal vias was 250 mu m. The optimum heat flux area ratio between the Si submount and the LED chip was 25. The thermal resistance of an Si submount 250 mu m thick and 25 mm(2) in area was 1.85 K/W without Cu vias. This value decreased to 1.50 K/W on incorporation of the 400-mu m-diameter Cu vias. In addition, the total thermal resistance of the LED package structure was improved from 9.7 K/W to 8.3 K/W on incorporation of the 400-mu m-diameter Cu vias into the Si submount.