Wrap around contact process margin improvement with early contact cut
A method is presented for forming a wrap around contact. The method includes forming a p-type epitaxial region and an n-type epitaxial region over a substrate, forming a dielectric pillar between the p-type epitaxial region and the n-type epitaxial region, depositing sacrificial liners around both the p-type epitaxial region and the n-type epitaxial region, and depositing an inter-layer dielectric (ILD). The method further includes forming trenches in the ILD extending into the sacrificial liners, wherein the trenches are vertically aligned with the p-type epitaxial region and the n-type epitaxial region, removing the sacrificial liners to define irregular-shaped openings exposing the p-type epitaxial region and the n-type epitaxial region, and filling the irregular-shaped openings with a conductive material defining the wrap around contact.
1. A method for forming a wrap around contact, the method comprising:
forming a p-type epitaxial region and an n-type epitaxial region over a substrate;
forming a dielectric pillar between the p-type epitaxial region and the n-type epitaxial region;
depositing sacrificial liners around both the p-type epitaxial region and the n-type epitaxial region such that at least one sacrificial liner of the sacrificial liners directly contacts vertical sidewalls of the dielectric pillar, the vertical sidewalls being perpendicular to the substrate;
depositing an inter-layer dielectric (ILD);
forming trenches in the ILD extending into the sacrificial liners, wherein the trenches are vertically aligned with the p-type epitaxial region and the n-type epitaxial region;
removing the sacrificial liners to define irregular-shaped openings exposing the p-type epitaxial region and the n-type epitaxial region; and
filling the irregular-shaped openings with a conductive material defining the wrap around contact.
2. The method of claim 1 , wherein the wrap around contact directly contacts top surfaces and sidewalls of both the p-type epitaxial region and the n-type epitaxial region.
3. The method of claim 1 , wherein the dielectric pillar extends above topmost surfaces of the p-type epitaxial region and the n-type epitaxial region.
4. The method of claim 1 , wherein the sacrificial liners include a first sacrificial liner and a second sacrificial liner.
5. The method of claim 4 , wherein the first sacrificial liner is a dielectric layer and the second sacrificial liner is a titanium nitride (TiN) layer.
6. The method of claim 1 , wherein a distance between a sidewall of the n-type epitaxial region and a sidewall of the dielectric pillar is at least 3 nm.
7. The method of claim 1 , wherein the conductive material defining the wrap around contact directly contacts sidewalls of the dielectric pillar.
8. The method of claim 1 , wherein a wrap around contact section adjacent the n-type epitaxial region has a different width than a wrap around contact section adjacent the p-type epitaxial region.
9. A method for forming a wrap around contact, the method comprising:
forming a dielectric pillar between a first epitaxial region and a second epitaxial region;
depositing sacrificial liners around the first and second epitaxial regions such that at least one sacrificial liner of the sacrificial liners directly contacts sidewalls of the dielectric pillar;
depositing an inter-layer dielectric (ILD);
forming trenches in the ILD extending above the first and second epitaxial regions;
removing the sacrificial liners to define openings exposing the first and second epitaxial regions; and
filling the openings with a conductive material defining the wrap around contact,
wherein a wrap around contact section adjacent the first epitaxial region has a different width than a wrap around contact section adjacent the second epitaxial region.
10. The method of claim 9 , wherein the wrap around contact directly contacts top surfaces and sidewalls of the first and second epitaxial regions.
11. The method of claim 9 , wherein the dielectric pillar extends above topmost surfaces of the first and second epitaxial regions.
12. The method of claim 9 , wherein the sacrificial liners include a first sacrificial liner and a second sacrificial liner.
13. The method of claim 9 , wherein a distance between a sidewall of the first epitaxial region and a sidewall of the dielectric pillar is at least 3 nm.
14. The method of claim 9 , wherein the conductive material defining the wrap around contact directly contacts sidewalls of the dielectric pillar.
15. The method of claim 9 , wherein the openings are irregular-shaped openings.
16. A method for forming a wrap around contact, the method comprising:
forming a dielectric pillar between a first epitaxial region and a second epitaxial region;
depositing sacrificial liners around the first and second epitaxial regions such that at least one sacrificial liner of the sacrificial liners directly contacts sidewalls of the dielectric pillar;
depositing an inter-layer dielectric (ILD);
forming trenches in the ILD extending above the first and second epitaxial regions;
removing the sacrificial liners to define openings exposing the first and second epitaxial regions; and
filling the openings with a conductive material defining the wrap around contact,
wherein the sacrificial liners include a first sacrificial liner and a second sacrificial liner, the first sacrificial liner is a dielectric layer and the second sacrificial liner is a titanium nitride (TiN) layer.
17. The method of claim 16 , wherein a wrap around contact section adjacent the first epitaxial region has a different width than a wrap around contact section adjacent the second epitaxial region.
18. The method of claim 16 , wherein the conductive material defining the wrap around contact directly contacts sidewalls of the dielectric pillar.
19. The method of claim 16 , wherein the openings are irregular-shaped openings.
20. The method of claim 16 , wherein the wrap around contact directly contacts top surfaces and sidewalls of the first and second epitaxial regions.