the bottom surface of the substrate to the top metal surface underlying the led similar to other embodiments the sub mount 14 includes a bottom layer or substrate 32 of copper onto which is layered a first dielectric layer 38 a middle layer 36 of cu is deposited or layered above the first dielectric 38 and a second dielectric 34 is layered above the middle cu layer a top metal layer of cu is layered above the dielectric 34 the top metal layer is patterned to isolate conductive pads or electrodes 26 and 28 additionally a reflective layer 40 may be layered or deposited above the top layer of copper a thermally conductive core 50 is formed by metal layers 36 52 54 and 56 the led 20 is positioned above this metal core and heat from the led dissipates through the metal layers to the bottom and outwards through metal layer 36 electrical leads 16 electrically interconnect the led 20 with the conductive pads 26 and 28 fig4 illustrates an embodiment of the led package 10 including a sub mount 14 led 20 and electrical leads 16 wherein the metal core supporting the led extends from the bottom surface of the substrate to the top metal surface underlying the led similar to other embodiments the sub mount 14 includes a bottom layer or substrate 32 of copper onto which is layered a first dielectric layer 34 the top metal layer is deposited above the dielectric layer 34 and patterned to isolate conductive pads or electrodes 26 and 28 a.