Method to recess cobalt for gate metal application
First Claim
1. A method of forming a semiconductor structure comprising:
- forming a gate structure over a semiconductor material portion, wherein the gate structure comprises, from bottom to top, a gate dielectric, a gate electrode and a gate cap;
forming a gate spacer on sidewalls of the gate structure;
forming a source/drain region on each side of the gate structure;
forming an interlevel dielectric (ILD) layer over each source/drain region and laterally surrounding the gate structure;
patterning the ILD layer to form a contact opening, wherein the contact opening extends through the ILD layer and physically exposes a surface of the source/drain regions and the gate structure, and the patterning the ILD layer also recesses the gate cap and gate spacer exposed by the contact opening;
forming a contact liner and a cobalt contact structure within the contact opening, wherein a portion of the contact liner and a portion of the cobalt contact structure are located above the recessed gate cap and recessed gate spacer;
recessing the cobalt contact conductor to provide a cobalt contact conductor portion overlying the source/drain regions, wherein the recessing the cobalt contact conductor is performed by repeating steps of oxidizing the cobalt contact conductor to form a cobalt oxide layer on a surface of the cobalt contact conductor and removing the cobalt oxide layer; and
recessing the contact liner to provide a contact liner portion contacting one of the source/drain regions.
8 Assignments
0 Petitions
Accused Products
Abstract
After forming a material stack including a gate dielectric, a work function metal and a cobalt gate electrode in a gate cavity formed by removing a sacrificial gate structure, the cobalt gate electrode is recessed by oxidizing the cobalt gate electrode to provide a cobalt oxide layer on a surface of the cobalt gate electrodes and removing the cobalt oxide layer from the surface of the cobalt gate electrodes by a chemical wet etch. The oxidation and oxide removal steps can be repeated until the cobalt gate electrode is recessed to any desired thickness. The work function metal can be recessed after the recessing of the cobalt gate electrode is completed or during the recessing of the cobalt gate electrode.
-
Citations
17 Claims
-
1. A method of forming a semiconductor structure comprising:
-
forming a gate structure over a semiconductor material portion, wherein the gate structure comprises, from bottom to top, a gate dielectric, a gate electrode and a gate cap; forming a gate spacer on sidewalls of the gate structure; forming a source/drain region on each side of the gate structure; forming an interlevel dielectric (ILD) layer over each source/drain region and laterally surrounding the gate structure; patterning the ILD layer to form a contact opening, wherein the contact opening extends through the ILD layer and physically exposes a surface of the source/drain regions and the gate structure, and the patterning the ILD layer also recesses the gate cap and gate spacer exposed by the contact opening; forming a contact liner and a cobalt contact structure within the contact opening, wherein a portion of the contact liner and a portion of the cobalt contact structure are located above the recessed gate cap and recessed gate spacer; recessing the cobalt contact conductor to provide a cobalt contact conductor portion overlying the source/drain regions, wherein the recessing the cobalt contact conductor is performed by repeating steps of oxidizing the cobalt contact conductor to form a cobalt oxide layer on a surface of the cobalt contact conductor and removing the cobalt oxide layer; and recessing the contact liner to provide a contact liner portion contacting one of the source/drain regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
Specification