Recessed metal liner contact with copper fill
A method of fabricating a contact above a source or drain region of an integrated circuit includes depositing a first liner conformally in a bottom and along a sidewall of a trench formed above the source or drain region, depositing a second liner conformally over the first liner, and stripping the first liner and the second liner from a portion of the sidewall from an opening of the trench to a height above the bottom of the trench. The method also includes depositing a third liner conformally over the second liner on the bottom and to the height above the bottom of the trench and on the portion of the sidewall, and depositing a metal fill to fill the trench.
1. A contact for a source or drain region of an integrated circuit, the contact comprising:
a first liner conformally disposed to cover a bottom of the contact and along a sidewall of the contact from the bottom to a height, the height being less than a full height of the contact such that a portion of the sidewall of the contact is not covered by the first liner;
a second liner conformally disposed over the first liner on the bottom and up to the height of the sidewall of the contact;
a third liner conformally disposed over the second liner on the bottom and up to the height of the sidewall and also covering the portion of the sidewall of the contact; and
a metal fill filling a volume of the contact defined by the third liner.
2. The contact according to claim 1 , wherein the first liner is titanium.
3. The contact according to claim 1 , wherein the second liner is titanium nitride.
4. The contact according to claim 1 , wherein the third liner is tantalum.
5. The contact according to claim 1 , wherein the third liner is tantalum nitride.
6. The contact according to claim 1 , wherein the third liner is ruthenium.
7. The contact according to claim 1 , wherein the third liner is a combination of tantalum, tantalum nitride, and ruthenium.
8. The contact according to claim 1 , wherein the metal fill is copper.
9. The contact according to claim 1 , wherein the height is a sum of 6-15 nanometers and a thickness of the first liner and the second liner on the bottom of the contact.
10. The contact according to claim 1 , wherein a thickness of a combination of the first liner and the second liner along the sidewall up to the height of the sidewall is 7-20 nanometers.
11. The contact according to claim 1 , wherein the first liner is deposited on the source region of the integrated circuit.
12. The contact according to claim 1 , wherein the first liner is deposited on the drain region of the integrated circuit.
13. The contact according to claim 1 , wherein the metal fill is covered by a liner of another contact.
14. The contact according to claim 1 , wherein the third liner covering the portion of the sidewall of the contact is adjacent to an interlayer dielectric material.