Source and drain contact cut last process to enable wrap-around-contact
A technique relates to a semiconductor device. A source or drain (S/D) contact liner is formed on one or more S/D regions. Annealing is performed to form a silicide layer around the one or more S/D regions, the silicide layer being formed at an interface between the S/D contact liner and the S/D regions. A block layer is formed into a pattern over the one or more S/D regions, such that a portion of the S/D contact liner is protected by the block layer. Unprotected portions of the S/D contact liner are removed, such that the S/D contact liner protected by the block layer remains over the one or more S/D regions. The block layer and S/D contacts are formed on the S/D contact liner over the one or more S/D regions.
1. A method of forming a semiconductor device, the method comprising:
forming a source or drain (S/D) contact liner of conductive material on one or more S/D regions;
responsive to forming the S/D contact liner, annealing to form a silicide layer around the one or more S/D regions, the silicide layer being formed at an interface between the S/D contact liner and the S/D regions;
forming a block layer into a pattern over the one or more S/D regions, such that a top portion of the S/D contact liner is protected by the block layer, while unprotected portions of the S/D contact liner below the top portion are free of the block layer;
removing the unprotected portions of the S/D contact liner, such that the S/D contact liner protected by the block layer remains over the one or more S/D regions;
removing the block layer; and
forming S/D contacts on the S/D contact liner over the one or more S/D regions.
2. The method of claim 1 , wherein the one or more S/D regions are formed over one or more fins.
3. The method of claim 1 , wherein the S/D contact liner includes a first material formed directly on the one or more S/D regions and a second material formed on the first material.
4. The method of claim 3 , wherein annealing to form the silicide layer around the one or more S/D regions causes the first material to form the silicide layer around the one or more S/D regions.
5. The method of claim 1 , wherein removing the unprotected portions of the S/D contact liner, such that the S/D contact liner protected by the block layer remains over the one or more S/D regions comprises etching the unprotected portions of the S/D contact liner while not etching the silicide layer.
6. A method of forming a semiconductor device, the method comprising:
forming a source or drain (S/D) contact liner on one or more S/D regions;
annealing to form a silicide layer around the one or more S/D regions, the silicide layer being formed at an interface between the S/D contact liner and the S/D regions;
forming a block layer into a pattern over the one or more S/D regions, such that a portion of the S/D contact liner is protected by the block layer;
removing unprotected portions of the S/D contact liner, such that the S/D contact liner protected by the block layer remains over the one or more S/D regions;
removing the block layer; and
forming S/D contacts on the S/D contact liner over the one or more S/D regions, wherein removal of the unprotected portions of the S/D contact liner causes the silicide layer to be exposed underneath the one or more S/D regions.
7. The method of claim 1 , wherein a fill material is formed subsequent to removing the unprotected portions of the S/D contact liner.
8. The method of claim 7 , wherein the fill material is a dielectric material.
9. The method of claim 7 , wherein the fill material is formed in openings created by forming the block layer into the pattern over the one or more S/D regions.
10. The method of claim 7 , wherein removing the block layer creates an opening for the one or more S/D contacts.
11. The method of claim 10 , wherein the one or more S/D contacts are formed in the opening.
12. The method of claim 1 , wherein the S/D contact liner comprises a stack of titanium and titanium nitride.
13. The method of claim 1 , wherein the block layer comprises an organic planarization layer.
14. The method of claim 1 , wherein the one or more S/D contacts comprise metal.
15. A source/drain cut last method of forming a semiconductor device, the method comprising:
forming a source or drain (S/D) contact liner of conductive material on one or more S/D regions;
responsive to forming the S/D contact liner, annealing to form a silicide layer around the one or more S/D regions, the silicide layer being formed at an interface between the S/D contact liner and the S/D regions;
forming a block layer over the one or more S/D regions;
cutting a pattern of trenches in the block layer such that a top portion of the S/D contact liner is protected by the block layer, while unprotected portions of the S/D contact liner below the top portion are free of the block layer;
removing the unprotected portions of the S/D contact liner, such that the S/D contact liner protected by the block layer remains over the one or more S/D regions;
depositing a fill material in the trenches;
removing the block layer to leave S/D contact openings in the fill material; and
forming S/D contacts on the S/D contact liner over the one or more S/D regions, such that the S/D contacts are formed in the S/D contact openings.