Mask scheme for cut pattern flow with enlarged EPE window

1. A method of forming a semiconductor device, the method comprising:

forming a first spin-on-carbon layer, a hardmask and a photoresist on a film, the film comprising alternating columns of spacer mandrels and gapfill materials with oxide films located between the alternating columns of spacer mandrels and gapfill materials, the photoresist having an opening over one of the columns of gapfill materials;

etching the hardmask and the first spin-on-carbon layer through the opening in the photoresist to remove the photoresist and portions of the hardmask and the first spin-on-carbon layer to expose a top of one of the columns of gapfill materials;

removing the first spin-on-carbon layer, the hardmask and one of the columns of gapfill material to form a gap;

forming a second spin-on-carbon layer, a second hardmask and a second photoresist on the film, the second spin-on-carbon layer filling the gap, the film comprising alternating columns of spacer mandrels, gapfill materials, oxide films and the second spin-on-carbon layer, the second photoresist having a second opening over one of the columns of spacer mandrels;

etching the second hardmask and the second spin-on carbon layer through the second opening in the second photoresist to remove the second photoresist and portions of the second hardmask and second spin-on-carbon layer to expose a top of one of the columns of spacer mandrels;

removing the second spin-on-carbon layer, the second hardmask and the second spacer mandrel to form a second gap;

removing the oxide films to leave columns of the spacer mandrels and the gapfill materials on a first etch stop layer on a first oxide layer on a substrate, with exposed portions of the first etch stop layer and exposed portions of the first oxide layer on the substrate;

etching the exposed portions of the first etch stop layer and the first oxide layer and reducing a height of the columns of the spacer mandrels and the gapfill materials to expose portions of the substrate; and

fin etching the exposed portions of the substrate and removing the remaining columns of the spacer mandrels, the gapfill materials, the first etch stop layer and the first oxide layer.

2. The method of claim 1 , wherein forming the spin-on-carbon layer, the hardmask and the photoresist on the film, the film comprising alternating columns of spacer mandrels and gapfill materials with oxide films located between the alternating columns of spacer mandrels and gapfill materials, the photoresist having an opening over one of the columns of the gapfill materials comprises:

forming mandrels in an amorphous silicon layer on the first etch stop layer on the first oxide layer on the substrate;

forming a first conformal spacer layer on the mandrels;

removing the mandrels and square etching the conformal spacer layer to form spacer mandrels on the first etch stop layer, the spacer mandrels having a first side and a second side;

forming a second conformal oxide layer on the spacer mandrels;

etching the second conformal oxide layer to form the columns of oxide films on the first side and the second side of the spacer mandrels with a gap located between adjacent columns of oxide films; and

depositing a gapfill material in the gap.

3. The method of claim 2 , wherein the substrate is a silicon substrate.

4. The method of claim 2 , wherein the oxide layer on the substrate comprises silicon oxide.

5. The method of claim 2 , wherein the spacer mandrels comprise silicon nitride.

6. The method of claim 2 , wherein the gapfill materials comprise aluminum oxide.

7. The method of claim 2 , wherein the oxide films comprise silicon oxide.

8. The method of claim 2 , wherein the conformal spacer layer comprises silicon oxide.

9. The method of claim 1 , wherein forming the spin-on-carbon layer, hardmask and photoresist on the film, the film comprising alternating columns of spacer mandrels and gapfill materials with oxide films between, the photoresist having an opening over one of the gapfill materials comprises:

forming second mandrels in a second spin-on-carbon layer on a second etch stop layer on a silicon nitride layer on the first etch stop layer on the first oxide layer on the substrate;

forming a second conformal spacer layer on the second mandrels;

removing the second mandrels and square etching the second conformal spacer layer to form second spacer mandrels on the second etch stop layer, the second spacer mandrels having a first side and a second side;

performing a transfer etch process to remove the second spacer mandrels, the second etch stop layer and portions of the silicon nitride layer leaving spacer mandrels in the silicon nitride layer and exposing the first etch stop layer;

forming a third conformal oxide layer on the third spacer mandrels on the first etch stop layer;

etching the third conformal oxide layer to form columns of oxide films on both sides of the third spacer mandrels with a second gap located between adjacent columns of oxide films; and

depositing the gapfill material in the second gap.

10. The method of claim 9 , wherein the substrate is a silicon substrate.

11. The method of claim 9 , wherein the first oxide layer on the substrate comprises silicon oxide.

12. The method of claim 9 , wherein the second spacer mandrels comprise silicon nitride.

13. The method of claim 9 , wherein the gapfill materials comprise aluminum oxide.

14. The method of claim 9 , wherein the oxide films comprise silicon oxide.

15. The method of claim 9 , wherein the second conformal spacer layer comprises silicon oxide.

16. The method of claim 1 , wherein forming the spin-on-carbon layer, hardmask and photoresist on the film, the film comprising alternating columns of spacer mandrels and gapfill materials with oxide films between, the photoresist having an opening over one of the gapfill materials comprises:

forming second mandrels in a second spin-on-carbon layer on a second etch stop layer on an amorphous silicon layer on the first etch stop layer on the first oxide layer on the substrate;

forming a second conformal spacer layer on the second mandrels in the second spin-on-carbon layer;

removing the second mandrels and square etching the second conformal spacer layer to form second spacer mandrels on the second etch stop layer;

performing a transfer etch process to remove the second spacer mandrels, the second etch stop layer and portions of the amorphous silicon layer leaving spacer mandrels of amorphous silicon and exposing the first etch stop layer;

forming a third conformal oxide layer on the spacer mandrels of amorphous silicon on the first etch stop layer;

etching the third conformal oxide layer to form columns of oxide films on both sides of the spacer mandrels of amorphous silicon with a third gap located between adjacent columns of oxide films;

depositing a second gapfill material in the third gap;

removing the spacer mandrels of amorphous silicon leaving fourth gaps located between adjacent columns of oxide films; and

depositing a silicon nitride film in the fourth gaps.

17. The method of claim 16 , wherein the first oxide layer on the substrate comprises silicon oxide.

18. The method of claim 16 , wherein the second spacer mandrels comprise silicon nitride.

19. The method of claim 16 , wherein the gapfill materials comprise aluminum oxide.

20. The method of claim 16 , wherein the oxide films comprise silicon oxide.