Non-mandrel cut formation
Methods of forming non-mandrel cuts. A dielectric layer is formed on a metal hardmask layer, and a patterned sacrificial layer is formed on the dielectric layer. The dielectric layer is etched to form a non-mandrel cut in the dielectric layer that is vertically aligned with the opening in the patterned sacrificial layer. A metal layer is formed on an area of the metal hardmask layer exposed by the non-mandrel cut in the dielectric layer. The metal hardmask layer is patterned with the metal layer masking the metal hardmask layer over the area.
1. A method comprising:
forming a first dielectric layer on a metal hardmask layer;
forming a first mandrel and a second mandrel on the first dielectric layer;
forming a patterned sacrificial layer on the first dielectric layer;
etching the first dielectric layer to form a non-mandrel cut in the first dielectric layer that is vertically aligned with an opening in the patterned sacrificial layer;
forming a metal layer on an area of the metal hardmask layer exposed by the non-mandrel cut in the first dielectric layer; and
patterning the metal hardmask layer with the metal layer masking the metal hardmask layer over the area.
2. The method of claim 1 further comprising:
forming a first sidewall spacer on the first dielectric layer adjacent to the first mandrel; and
forming a second sidewall spacer on the first dielectric layer adjacent to the second mandrel,
wherein the area is located between the first sidewall spacer and the second sidewall spacer.
3. The method of claim 2 wherein, when the metal hardmask layer is patterned, the first sidewall spacer and the second sidewall spacer mask the metal hardmask layer, a first section of the first dielectric layer is located vertically between the first sidewall spacer and the metal hardmask layer, and a second section of the first dielectric layer is located vertically between the second sidewall spacer and the metal hardmask layer.
4. The method of claim 2 further comprising:
removing the first mandrel selective to the first sidewall spacer; and
removing the second mandrel selective to the second sidewall spacer,
wherein the metal layer is deposited after the first mandrel and the second mandrel are removed.
5. The method of claim 4 wherein the non-mandrel cut is formed in the first dielectric layer before the first mandrel and the second mandrel are removed.
6. The method of claim 4 wherein the first dielectric layer is revealed at a first location revealed by the removal of the first mandrel and at a second location revealed by the removal of the second mandrel further comprising:
removing the first dielectric layer from the first location and the second location.
7. The method of claim 6 wherein the metal hardmask layer is patterned after the first dielectric layer is removed from the first location and the second location.
8. The method of claim 2 further comprising:
removing the first mandrel selective to the first sidewall spacer; and
removing the second mandrel selective to the second sidewall spacer,
wherein the metal layer is deposited before the first mandrel and the second mandrel are removed.
9. The method of claim 8 wherein the non-mandrel cut is formed in the first dielectric layer before the first mandrel and the second mandrel are removed.
10. The method of claim 8 wherein the first mandrel and the second mandrel are removed by an etching process, and the metal layer is masked by an etch mask when the first mandrel and the second mandrel are removed.
11. The method of claim 8 further comprising:
removing the first dielectric layer at a first location revealed by the removal of the first mandrel and at a second location revealed by the removal of the second mandrel.
12. The method of claim 11 wherein the metal hardmask layer is patterned after the first dielectric layer is removed at the first location revealed by the removal of the first mandrel and at the second location revealed by the removal of the second mandrel.
13. The method of claim 2 wherein the first dielectric layer and the metal hardmask layer are formed as a layer stack on a second dielectric layer, and further comprising:
removing the first mandrel selective to the first sidewall spacer; and
removing the second mandrel selective to the second sidewall spacer,
after the metal hardmask layer is patterned, etching the second dielectric layer to form a trench between the first sidewall spacer and the second sidewall spacer,
wherein a section of the second dielectric layer is masked during etching by the area of the metal hardmask layer to transfer the non-mandrel cut to the second dielectric layer.
14. The method of claim 13 further comprising:
filling the trench with a conductor layer to form a first wire having an end and a second wire having an end separated from the end of the first wire by the section of the second dielectric layer.
15. The method of claim 2 wherein forming the metal layer on the area of the metal hardmask layer exposed by the non-mandrel cut in the first dielectric layer comprises:
selectively depositing the metal layer on the area of the metal hardmask layer.
16. The method of claim 1 wherein the metal layer is comprised of ruthenium, copper, or cobalt.
17. The method of claim 1 wherein forming the metal layer on the area of the metal hardmask layer exposed by the non-mandrel cut in the first dielectric layer comprises:
selectively depositing the metal layer on the area of the metal hardmask layer.
18. The method of claim 17 wherein the metal layer is selectively deposited by atomic layer deposition, electroless deposition, or chemical vapor deposition.
19. The method of claim 1 wherein the patterned sacrificial layer is removed before the metal layer is formed on the area of the metal hardmask layer exposed by the non-mandrel cut in the first dielectric layer.