METHOD OF FILLING RETROGRADE RECESSED FEATURES

Methods for void-free material filling of fine recessed features have been disclosed in various embodiments. According to one embodiment, the method includes a) providing a substrate containing a recessed feature having an opening, a sidewall and a bottom, the sidewall including an area of retrograde profile relative to a direction extending from a top of the recessed feature to the bottom of the recessed feature, b) depositing an amount of a material in the recessed feature, the material having a greater thickness at the bottom than on the sidewall of the recessed feature, c) stopping the depositing in step b) before the recessed feature is fully filled with the material, d) etching a portion of the material from the recessed feature, and e) depositing an additional amount of the material to fully fill the recessed feature with the material without any voids in the recessed feature.