Etch stop for copper damascene process

A method for manufacturing a double layered copper connector comprising:

• (a) providing a partially completed integrated circuit;
• (b) depositing a first insulating layer, having an upper surface, on said integrated circuit;
• (c) patterning and then etching said first insulating layer to form a cavity extending down to the level of said integrated circuit;
• (d) depositing a first barrier layer on the walls of said cavity and on the upper surface said first insulating layer;
• (e) patterning and etching said first barrier layer so that it extends for some distance, on the upper surface of said first insulating layer, on all sides of the cavity;
• (f) depositing a second insulating layer, having upper and lower surfaces, on the upper surface of said first insulating layer;
• (g) patterning and then etching said second insulating layer to form a trench therein, said trench being narrower than said extension of the first barrier layer, wider than said cavity, and symmetrically disposed over said cavity;
• (h) depositing a second barrier layer on the walls of both the trench and the cavity and on the upper surface of said second insulating layer;
• (i) depositing a copper layer to more than fill said cavity and said trench;
• (j) removing said copper layer and said second barrier layer to the level of the upper surface of said second insulating layer, thereby forming a first dual damscene copper connector having an upper surface;
• (k) depositing an etch stop barrier layer on the upper surface of the second insulating layer and on the upper surface of said damascene connector;
• (l) patterning and etching said etch stop barrier layer so that it slightly overlaps said upper surface of said damascene connector;
• and
• (m) forming a second dual damascene connector, disposed directly above the first dual damascene connector, in the manner recited in steps (b) through (j) above.