Semiconductor device structure with silicide and method for forming the same

1. A method for forming a semiconductor device structure, comprising:

providing a substrate, wherein the substrate has a base portion and a fin portion over the base portion;

forming a first spacer layer over the base portion and a first sidewall of the fin portion;

forming a first dielectric fin over the first spacer layer, wherein the first spacer layer separates the first dielectric fin from the fin portion and the base portion;

forming an epitaxial structure over the fin portion, wherein the first spacer layer is partially between the epitaxial structure and the first dielectric fin;

removing the first spacer layer between the epitaxial structure and the first dielectric fin; and

forming a silicide layer wrapping around the epitaxial structure.

2. The method for forming the semiconductor device structure as claimed in claim 1 , further comprising:

forming a second spacer layer over a second sidewall of the fin portion and the base portion during forming the first spacer layer over the first sidewall and the base portion, wherein the epitaxial structure is between the first spacer layer and the second spacer layer;

forming a second dielectric fin over the second spacer layer during forming the first dielectric fin over the first spacer layer, wherein the second spacer layer separates the second dielectric fin from the fin portion and the base portion, and the second spacer layer is partially between the epitaxial structure and the second dielectric fin; and

removing the second spacer layer between the epitaxial structure and the second dielectric fin during removing the first spacer layer between the epitaxial structure and the first dielectric fin.

3. The method for forming the semiconductor device structure as claimed in claim 2 , further comprising:

forming a first dielectric layer over the epitaxial structure, the first spacer layer, the second spacer layer, the first dielectric fin, and the second dielectric fin before removing the first spacer layer between the epitaxial structure and the first dielectric fin; and

partially removing the first dielectric layer to form a contact hole passing through the first dielectric layer and partially exposing the epitaxial structure, the first spacer layer, and the second spacer layer before removing the first spacer layer between the epitaxial structure and the first dielectric fin, wherein the first spacer layer between the epitaxial structure and the first dielectric fin and the second spacer layer between the epitaxial structure and the second dielectric fin are removed through the contact hole; and

forming a contact structure in the contact hole.

4. The method for forming the semiconductor device structure as claimed in claim 3 , wherein the contact hole partially exposes the first dielectric fin.

5. The method for forming the semiconductor device structure as claimed in claim 2 , further comprising:

conformally forming a second dielectric layer over the base portion and the first sidewall and the second sidewall of the fin portion before forming the first spacer layer and the second spacer layer,

wherein the first spacer layer, the second spacer layer, the first dielectric fin, and the second dielectric fin are formed over the second dielectric layer, the first spacer layer separates the second dielectric layer from the first dielectric fin, and the second spacer layer separates the second dielectric layer from the second dielectric fin.

6. The method for forming the semiconductor device structure as claimed in claim 5 , wherein the first spacer layer and the second spacer layer are conformally formed over the second dielectric layer.

7. The method for forming the semiconductor device structure as claimed in claim 5 , wherein the first spacer layer, the first dielectric fin, and the second dielectric layer are made of different materials.

8. The method for forming the semiconductor device structure as claimed in claim 1 , wherein the epitaxial structure is in direct contact with the first spacer layer before removing the first spacer layer between the epitaxial structure and the first dielectric fin.

9. The method for forming the semiconductor device structure as claimed in claim 1 , wherein the silicide layer is in direct contact with the first dielectric fin.

10. The method for forming the semiconductor device structure as claimed in claim 1 , wherein the first spacer layer wraps around the first dielectric fin.

11. A method for forming a semiconductor device structure, comprising:

providing a substrate, wherein the substrate has a base portion and a fin portion over the base portion;

forming a first dielectric layer over the base portion and a first sidewall of the fin portion;

forming a spacer layer over the first dielectric layer;

forming a dielectric fin over the spacer layer, wherein the spacer layer separates the dielectric fin from the first dielectric layer;

forming an epitaxial structure over the fin portion, wherein a void is surrounded by the epitaxial structure, the first dielectric layer, the spacer layer, and the dielectric fin;

removing the spacer layer between the epitaxial structure and the dielectric fin; and

forming a silicide layer over the epitaxial structure, wherein a first lower portion of the silicide layer covers a lower surface of the epitaxial structure and is in the void.

12. The method for forming the semiconductor device structure as claimed in claim 11 , further comprising:

forming a second dielectric layer over the epitaxial structure, the spacer layer, and the dielectric fin before removing the spacer layer between the epitaxial structure and the dielectric fin; and

partially removing the second dielectric layer to form a contact hole passing through the second dielectric layer and partially exposing the epitaxial structure and the spacer layer before removing the spacer layer between the epitaxial structure and the dielectric fin, wherein the spacer layer between the epitaxial structure and the dielectric fin is removed through the contact hole; and

forming a contact structure in the contact hole.

13. The method for forming the semiconductor device structure as claimed in claim 12 , wherein the void communicates with the contact hole after removing the spacer layer between the epitaxial structure and the dielectric fin.

14. The method for forming the semiconductor device structure as claimed in claim 13 , wherein the forming of the silicide layer over the epitaxial structure comprises:

forming a metal layer over the epitaxial structure, wherein a second lower portion of the metal layer covers the lower surface of the epitaxial structure and is in the void;

annealing the metal layer and the epitaxial structure to react the metal layer with the epitaxial structure so as to form the silicide layer; and

performing an etching process to remove the metal layer that has not reacted with the epitaxial structure.

15. The method for forming the semiconductor device structure as claimed in claim 14 , wherein the metal layer that has not reacted with the epitaxial structure partially remains in the void after the etching process.

16. A semiconductor device structure, comprising:

a substrate having a base portion and a fin portion over the base portion;

an epitaxial structure over the fin portion;

a first dielectric layer over the base portion and a first sidewall of the fin portion;

a spacer layer over the first dielectric layer;

a dielectric fin over the spacer layer, wherein the spacer layer separates the dielectric fin from the first dielectric layer, and a void is surrounded by the epitaxial structure, the first dielectric layer, the spacer layer, and the dielectric fin; and

a silicide layer wrapping around the epitaxial structure and extending into the void.

17. The semiconductor device structure as claimed in claim 16 , wherein a first top surface of the first dielectric layer is lower than a second top surface of the spacer layer, and the second top surface is lower than a third top surface of the dielectric fin.

18. The semiconductor device structure as claimed in claim 16 , wherein the silicide layer is in direct contact with the dielectric fin.

19. The semiconductor device structure as claimed in claim 16 , wherein a lower portion of the silicide layer conformally covers a lower surface of the epitaxial structure, and the lower portion is in the void.

20. The semiconductor device structure as claimed in claim 16 , further comprising:

a second dielectric layer over the epitaxial structure, the spacer layer, and the dielectric fin; and

a contact structure passing through the second dielectric layer to connect to the silicide layer.