Dual damascene with a protective mask for via etching

A method of fabricating interconnecting conductive lines and conductive vias in a layer of insulating material comprising the steps of:

• forming a conductive line opening with sidewalls and a bottom in a layer of insulating material and having a thickness from its upper surface to partially through said thickness, said thickness being the thickness of the conductive line to be formed;
• covering the surface of the insulating material and the sidewalls and the bottom of the conductive line opening with a layer of a thin conformal etch barrier material of titanium nitrite;
• forming a via opening in said barrier layer at the bottom of the conductive line opening and in alignment with the line opening;
• etching a via opening in the remaining portion of the thickness of said insulating layer by using said via opening in the barrier layer as an etch mask for said etching;
• and
• filling said conductive line opening and said via opening with a conductive material without removing the etch barrier.

A method of fabricating interconnecting conductive lines and conductive vias in a layer of insulating material having an upper portion and a lower portion and of a thickness to contain both the conductive lines and vias comprising the steps of:

• forming a conductive line openings with sidewalls and a bottom in an upper portion of a layer of insulating material and having an upper surface, the depth of the insulating layer from the upper surface being about the thickness of the conductive line to be formed;
• covering the surface of the insulating layer and the sidewalls and the bottom of the conductive line opening with a layer of thin conformal etch barrier material;
• forming a via opening in said barrier layer at the bottom of the conductive line opening, in alignment with the line opening, and without removing any of the barrier layer on the sidewalls;
• etching a via opening in the lower portion of the layer of insulating material by using said via opening in said barrier layer as an etch mask for said etching;
• and
• filling said conductive line opening and said via opening with a conductive material without removing the etch barrier.