Method of improving an etching profile in dual damascene etching

A plasma etching method for improving an etching profile in a dual damascene structure comprising the steps of:

• providing a substrate including an oxide containing insulating layer in a multilayer semiconductor device;
• providing a patterned photoresist layer exposing an uppermost layer of the substrate for anisotropically plasma etching a via opening;
• anisotropically plasma etching through a thickness of at least a portion of the substrate to form the via opening;
• blanket depositing an etching stop liner to cover at least a portion of the sidewalls of the via opening;
• patterning according to a photolithographic process for etching a trench line opening at least partially overlying and encompassing the via opening;
• and,
• anisotropically plasma etching through at least another portion of the thickness of the substrate including the via opening to form a trench line opening at least partially overlying a remaining portion of the via opening to form a dual damascene structure.