an underfill formation technique for leds molds a reflective underfill material to encapsulate led dies mounted on a submount wafer while forming a reflective layer of the underfill material over the submount wafer . the underfill material is then hardened , such as by curing . the cured underfill material over the top of the led dies is removed using microbead blasting while leaving the reflective layer over the submount surface . the exposed growth substrate is then removed from all the led dies , and a phosphor layer is molded over the exposed led surface . a lens is then molded over the leds and over a portion of the reflective layer . the submount wafer is then singulated . the reflective layer increases the efficiency of the led device by reducing light absorption by the submount without any additional processing steps .