Copper interconnect structures and methods of making same

1. A method, comprising:

forming a dielectric layer on a substrate;

simultaneously forming a first trench and a second trench in said dielectric layer;

simultaneously forming a first liner on sidewalls and a bottom of said first trench and a second liner on sidewalls an a bottom of said second trench;

simultaneously filling all remaining space in said first trench with a first copper layer to form a first wire in said dielectric layer and filling all remaining space in said second trench with a second copper layer to form a second wire in said dielectric layer;

forming a third trench in said dielectric layer;

forming a third liner on sidewalls and a bottom of said third trench; and

filling all remaining space in said third trench with a third copper layer to form an electromigration stop in said dielectric layer, said electromigration stop between and abutting respective ends of said first wire and said second wire.

2. The method of claim 1 , wherein regions of said first liner on a sidewall of said first trench abut a region of said third liner on a first sidewall of said third trench and regions of said second liner on a sidewall of said second trench abut a region of said third liner on a second and opposite sidewall of said third trench.

3. The method of claim 1 , wherein regions of said first liner on a sidewall of said first trench abut a region of said third liner on a first sidewall of said third trench and regions of said second liner on a sidewall of said second trench abut a region of said third liner on a second and adjacent sidewall of said third trench.

4. The method of claim 1 , wherein a first region of said first wire abutting said electromigration etch stop and a second region of said second wire abutting said electromigration stop extend from a top surface of said dielectric layer into said dielectric layer a first distance and said electromigration stop extends from said top surface of said dielectric layer into said dielectric layer a second distance, said first distance greater than said second distance.

5. The method of claim 1 , wherein a first region of said first wire abutting said electromigration etch stop and a second region of said second wire abutting said electromigration stop extend from a top surface of said dielectric layer into said dielectric layer a first distance and said electromigration stop extends from said top surface of said dielectric layer into said dielectric layer a second distance, said second distance greater than said first distance.

6. The method of claim 1 , further including:

simultaneously with forming said first and second trenches, forming a fourth trench in said dielectric layer;

simultaneously with forming said first and second liners, forming an electrically conductive fourth liner on sidewalls and a bottom of said fourth trench;

simultaneously with filling said remaining space in said first and second trenches, filling all remaining space in said fourth trench with a fourth copper layer to form a third wire in said dielectric layer;

wherein said a first wire abuts said electromigration stop on a first side of said electromigration stop and said second wire and third wire abut said electromigration stop on a second side of said electromigration stop;

wherein said first liner, said second liner, said third liner and said fourth liner are copper diffusion barrier; and

wherein top surfaces of said first wire, said second wire, said third wire, said electromigration stop and said dielectric layer are coplanar.

7. The method of claim 1 , further including:

simultaneously with forming said first and second trenches, forming a fourth trench in said dielectric layer;

simultaneously with forming said first and second liners, forming an electrically conductive fourth liner on sidewalls and a bottom of said fourth trench;

simultaneously with filling said remaining space in said first and second trenches, filling all remaining space in said fourth trench with a fourth copper layer to form a third wire in said dielectric layer;

wherein said a first wire abuts said electromigration stop on a first side of said electromigration stop, said a second wire abuts said electromigration stop on a second side of said electromigration stop, and said a third wire abuts said electromigration stop on a third side of said electromigration stop;

wherein said first liner, said second liner, said third liner and said fourth liner are copper diffusion barriers; and

wherein top surfaces of said first wire, said second wire, said third wire, said electromigration stop and said dielectric layer are coplanar.

8. The method of claim 1 , further including:

simultaneously with forming said first and second trenches, forming a fourth trench and a fifth trench in said dielectric layer;

simultaneously with forming said first and second liners, forming an electrically conductive fourth liner on sidewalls and a bottom of said fourth trench and an electrically conductive fifth liner on sidewalls and a bottom of said fifth trench;

simultaneously with filling said remaining space in said first and second trenches, filling all remaining space in said fourth trench with a fourth copper layer to form a third wire and filling all remaining space in said fifth trench with a fifth copper layer to form a fourth wire;

wherein said first wire abuts said electromigration stop on first side of said electromigration stop, said second wire abuts said electromigration stop on second side of said electromigration stop, said third wire abuts said electromigration stop on third side of said electromigration stop, said fourth wire abuts said electromigration stop on fourth side of said electromigration stop;

wherein said first side of said electromigration stop is opposite said second side of said electromigration stop and said third side of said electromigration stop is opposite said fourth side of said electromigration stop;

wherein said first liner, said second liner, said third liner and said fourth liner are copper diffusion barriers; and

wherein top surfaces of said first wire, said second wire, said third wire, said fourth wire, said electromigration stop and said dielectric layer are coplanar.

9. The method of claim 8 , wherein said electromigration stop includes a body portion and four integral corner projections, each corner projection extending along adjacent sides of respective pairs of said first and second wires, said second and third wires said third and fourth wires and said fourth and first wires, said corner projections including a region of said third liner and said third copper layer.

10. The method of claim 1 , further including:

simultaneously with forming said first and second trenches, forming a fourth trench in said dielectric layer;

simultaneously with forming said first and second liners, forming an electrically conductive fourth liner on sidewalls and a bottom of said fourth trench;

simultaneously with filling said remaining space in said first and second trenches, filling all remaining space in said fourth trench with a fourth copper layer to form a third wire in said dielectric layer;

simultaneously with forming said third trench, forming a fifth trench in said dielectric layer;

simultaneously with forming said electrically third liner, forming an electrically conductive fifth liner on sidewalls and a bottom of said fifth trench;

simultaneously with filling said all remaining space in said third trench, filling all remaining space in said fifth trench with a fifth copper layer to for an additional electromigration stop, said additional electromigration stop between and abutting respective ends of said second wire and said second wire, said end of said second wire abutting said additional electromigration stop opposite from said end of said second wire abutting said electromigration stop.

11. The method of claim 1 , wherein said first liner, said second liner and said third liner are copper diffusion barriers.

12. The method of claim 1 , wherein top surfaces of said first wire, said second wire, said electromigration stop and said dielectric layer are coplanar.

13. The method of claim 1 , wherein a first longitudinal axes of said first wire and a second longitudinal axes of said second wire are coaxial.

14. The method of claim 8 , wherein said first and second wires have a common first longitudinal axis and said third and fourth wires have a common second longitudinal axis, said first longitudinal axis perpendicular to said second longitudinal axis.

15. The method of claim 1 , wherein said first, said second and said third liners comprise a tantalum nitride layer on the sidewalls and bottom of said first, second and third trenches and a tantalum layer on said tantalum nitride layer.