Replacement metal gate structures
Replacement metal gate structures with improved chamfered workfunction metal and self-aligned contact and methods of manufacture are provided. The method includes forming a replacement metal gate structure in a dielectric material. The replacement metal gate structure is formed with a lower spacer and an upper spacer above the lower spacer. The upper spacer having material is different than material of the lower spacer. The method further includes forming a self-aligned contact adjacent to the replacement metal gate structure by patterning an opening within the dielectric material and filling the opening with contact material. The upper spacer prevents shorting with the contact material.
1. A method comprising:
forming a replacement metal gate structure and a self-aligned contact adjacent to the replacement metal gate structure, wherein the forming of the replacement gate structure comprises:
forming spacers within an opening of an interlevel dielectric;
depositing a gate dielectric material within the opening and over the spacers;
depositing a workfunction material on the gate dielectric material;
removing portions of the gate dielectric material and the workfunction material to form a space;
filling the space with a metal material;
depositing a spacer material on the spacers; and
chamfering the spacer material.
2. The method of claim 1 , wherein the replacement metal gate structure is formed in a dielectric material.
3. The method of claim 2 , wherein the self-aligned contact is formed by patterning an opening within the dielectric material and filling the opening within the dielectric material with a contact material.
4. The method of claim 1 , wherein each spacer comprises a lower spacer covered by the spacer material to form an upper spacer above the lower spacer.
5. The method of claim 4 , wherein the upper spacer is resistive to a self-aligned contact etching process.
6. The method of claim 4 , wherein the upper spacer has a material different than a material of the lower spacer.
7. The method of claim 4 , wherein the upper spacer prevents shorting with the contact material.
8. The method of claim 4 , wherein a material of the upper spacer is nitride and a material of the lower spacer is an oxide material.
9. The method of claim 1 , wherein the removing portions of the gate dielectric material and the workfunction material includes laterally removing the portions of the workfunction material and the gate dielectric material to form the space.
10. The method of claim 1 , further comprising forming a cap layer in the metal material.
11. The method of claim 10 , further comprising removing an upper portion of the metal material to form a recess for the cap layer, prior to forming the cap layer in the metal material.
12. The method of claim 11 , wherein the removing portions of the gate dielectric material and the workfunction material comprises removing upper portions of the workfunction material and the gate dielectric material to form the space.
13. The method of claim 12 , wherein the removing of the upper portions of the workfunction material and the gate dielectric material comprises laterally removing the upper portions of the workfunction material and the gate dielectric material.
14. The method of claim 13 , wherein the depositing the workfunction material on the gate dielectric material forms a seam in the workfunction material.
15. The method of claim 14 , wherein the laterally removing the upper portions of the workfunction material and the gate dielectric material prevents the seam from being etched through.
16. The method of claim 15 , further comprising plugging remaining portions of the seam with the metal material.
17. The method of claim 16 , further comprising etching the spacers back to correspond to a level of the seam.
18. The method of claim 17 , wherein the spacers are etched back to about 50% to 70% of a height of the workfunction material.
19. The method of claim 18 , wherein the etching back of the spacers forms openings on sides of the workfunction material.
20. The method of claim 19 , wherein the depositing the spacer material on the spacers comprises depositing the spacer material within the openings on the sides of the workfunction material.