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:
depositing a gate dielectric material within a replacement gate opening;
depositing a workfunction material on the gate dielectric material;
removing upper portions of the gate dielectric material and the workfunction material to form an upper space;
filling the upper space with a metal material;
removing an upper portion of a metal material to form a recess; and
forming a cap layer in the recess.
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 with contact material.
4. The method of claim 1 , wherein the replacement metal gate structure comprises a lower spacer and 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 the material of the upper spacer is nitride and the material of the lower spacer is an oxide material.
9. The method of claim 1 , wherein the removing step is laterally removing the upper portions of the workfunction material and the gate dielectric material to form the upper space.
10. The method of claim 1 , wherein the forming of the replacement gate structure further comprises:
providing a first material on sidewalls of a dummy gate opening, which is formed prior to the deposition of the gate dielectric material;
depositing the gate dielectric material on the first material;
recessing an upper portion of the first material to form a lower spacer in the replacement metal gate structure;
laterally etching of the upper portions of the workfunction material and the gate dielectric material from a space formed by the recessing of the first material; and
forming an upper spacer above the lower spacer, prior to filling of the space with the metal material.
11. The method of claim 10 , wherein the lateral etching opens a seam formed from deposition processes of the workfunction material.
12. The method of claim 11 , wherein the lateral etching removes upper portions of the gate dielectric material and the workfunction material, while preserving the workfunction material at a bottom of the seam.
13. The method of claim 12 , further comprising plugging the opened seam with the metal material and continuing a metal fill process adjacent to the upper spacer.
14. The method of claim 13 , wherein the forming of the self-aligned contact comprises etching an opening through the dielectric material, with the upper spacer acting as an etch stop to protect the metal material during the etching of the opening.