A method for manufacturing a semiconductor device includes forming a patterned photoresist layer over a substrate, performing a plasma ashing process to the patterned photoresist layer, thereby removing a portion of the patterned photoresist layer, exposing the patterned photoresist layer to broadband ultraviolet radiation and ozone, thereby removing other portions of the patterned photoresist layer, and performing a cleaning of the patterned photoresist layer after exposing the patterned photoresist layer to broadband ultraviolet radiation and ozone.