Gate cut with integrated etch stop layer
A method of forming a power rail to semiconductor devices comprising removing a portion of the gate structure forming a gate cut trench separating a first active region of fin structures from a second active region of fin structures. A conformal etch stop layer is formed in the gate cut trench. A fill material is formed on the conformal etch stop layer filling at least a portion of the gate cut trench. The fill material has a composition that is etched selectively to the conformal etch stop layer. A power rail is formed in the gate cut trench. The conformal etch stop layer obstructs lateral etching during forming the power rail to substantially eliminate power rail to gate structure shorting.
1. A method of forming a semiconductor structure, the method comprising:
forming a gate structure on first and second active regions of the semiconductor structure;
removing a portion of the gate structure to define a first gate structure on the first active region and a second gate structure on the second active region, wherein the first and second gate structures are in-line with one another and spaced apart by a gate cut trench;
forming a first etch stop layer in the gate cut trench;
forming a first dielectric material on the first etch stop layer in a lower portion of the gate cut trench;
forming a second etch stop layer on an upper surface of the first dielectric material; and
forming a second dielectric material on the second etch stop layer in an upper portion of the gate cut trench.
2. The method of claim 1 , further comprising:
removing a portion of the second dielectric material to form a recess in the gate cut trench; and
forming an electrically conductive material in the recess.
3. The method of claim 2 , wherein the electrically conductive material is selected from a group of: tungsten, cobalt, ruthenium, titanium, aluminum, and copper.
4. The method of claim 2 , wherein the electrically conductive material comprises a portion of a power rail or power rail interconnect.
5. The method of claim 2 , further comprising: planarizing the electrically conductive material to form a coplanar surface comprising an upper surface of the electrically conductive material, an upper surface of the first gate structure, and an upper surface of the second gate structure.
6. The method of claim 1 , wherein the first etch stop layer comprises an oxide.
7. The method of claim 6 , wherein the first etch stop layer comprises hafnium oxide.
8. The method of claim 1 , wherein the second etch stop layer comprises an oxide.
9. The method of claim 8 , wherein the second etch stop layer comprises hafnium oxide.
10. The method of claim 1 , wherein the first etch stop layer and the second etch stop layer comprise the same material.
11. The method of claim 1 , wherein forming the first etch stop layer comprises conformally depositing a first etch stop material.
12. The method of claim 1 , wherein forming the second etch stop layer comprises conformally depositing a second etch stop material.
13. The method of claim 11 , wherein forming the second etch stop layer comprises conformally depositing a second etch stop material.
14. The method of claim 13 , wherein the first and second etch stop materials are the same material.
15. The method of claim 1 , wherein forming the first dielectric material on the first etch stop layer in a lower portion of the gate cut trench further comprises:
depositing the first dielectric material in the gate cut trench; and
recessing the first dielectric material .
16. The method of claim 1 , wherein the first and second gate structures are dummy gate structures.
17. The method of claim 15 , wherein the first and second gate structures are dummy gate structures.
18. The method of claim 1 , wherein the first dielectric material comprises nitride.
19. The method of claim 1 , wherein the second dielectric material comprises nitride.
20. The method of claim 1 , wherein the first active region comprises a first fin structure.
21. The method of claim 20 , wherein the second active region comprises a second fin structure different from the first fin structure.
22. The method of claim 1 , wherein removing the portion of the gate structure comprises: removing upper portions of dielectric side wall spacers disposed on sidewalls of the gate structure.