Method of forming multi-level coplanar metal/insulator films using dual damascene with sacrificial flowable oxide

摘要

An improved method of performing a dual damascene etch through a layer stack disposed above a substrate. The layer stack includes an underlying device layer and an insulating layer disposed above the underlying device layer. The method includes forming a trench in a top surface of the insulating layer such that the trench is positioned over the underlying device layer and separated therefrom by insulating material at a bottom of the trench. The method also includes, depositing flowable oxide over the top surface of the insulating layer and into the trench followed by planarizing the flowable oxide down to about a level of the top surface of the insulating layer. Further, the method includes, etching through the flowable oxide within the trench and through insulating material at the bottom of the trench down to the underlying device layer to form a via.