The present disclosure provides a method for making a semiconductor device. The method includes forming a material layer on a substrate; forming a sacrificial layer on the material layer, where the material layer and sacrificial layer each as a thickness less than 100 angstrom; forming a patterned photoresist layer on the sacrificial layer; applying a first wet etching process to etch the sacrificial layer to form a patterned sacrificial layer using the patterned photoresist layer as a mask; applying a second wet etching process to etch the first material layer; and applying a third wet etching process to remove the patterned sacrificial layer.