Enhanced Optical–Thermal Performances of High-Power LED by Plated Copper on Thick Film Ceramic Substrate

Abstract

Thick printed ceramic substrate (TPC) is a promising technique for the packaging of high-power light-emitting diode (LED). Nevertheless, the incorporation of glass phase and voids in the sintered Ag layer decrease the electrical conductivity and heat dissipation of TPC substrate, which contributes to an increase in the junction temperature of LED. This article demonstrates a novel packaging design to plate copper on the sintered Ag layer of TPC substrate, which was applied to enhance the optical–thermal performances of high-power LED. After plating, the copper layers are well bonded with the Ag layer and the sheet resistance decreases rapidly. With the plated copper on thick film (PCTF) substrate package, the total thermal resistance is 17.45% lower than that with TPC package, while the junction temperature change of LED samples is 8.04 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C and 9.92 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C, respectively. Moreover, the surface temperature of LED sample packaged with PCTF is 11.16% lower than that with TPC at the working current of 1600 mA, and the optical power is 4.79% and 3.2% higher at the working current of 400 and 1200 mA, respectively. The results demonstrate that the optical–thermal performances of LED are enhanced by using the PCTF substrate due to its excellent heat dissipation.