Liner-less via contact
An interconnect structure and a method of forming the interconnect structure are provided. The interconnect structure includes a source drain contact above and contacting a source drain region of a semiconductor device. The interconnect structure also includes a via above and contacting the source drain contact. The via includes a lower portion with an uppermost surface that contacts a lowermost surface of an interlayer dielectric.
1 . An interconnect structure comprising:
a source drain contact formed from a single continuous metal layer, wherein a top region of the source drain contact is recessed and covered with a cap; and
a via above and contacting the source drain contact, wherein the via has an extended contact region into the cap over the source drain contact.
2 . The interconnect structure of claim 1 , wherein a sidewall of the extended contact region directly contacts a sidewall of the cap.
3 . The interconnect structure of claim 1 , wherein an uppermost surface of the extended contact region of the via is in direct contact with and substantially parallel to a lower surface of an interlayer dielectric.
4 . The interconnect structure of claim 3 , wherein the cap is below and contacting the interlayer dielectric.
5 . The interconnect structure of claim 1 , wherein a thickness of the cap is equal or substantially equal to a thickness of the extended contact region.
6 . The interconnect structure of claim 1 , wherein the cap is composed of a material selected from the group consisting of: aluminum oxide, titanium oxide, hafnium silicate, zirconium silicate, hafnium dioxide, and zirconium dioxide.
7 . The interconnect structure of claim 1 , wherein the source drain contact and the via are composed of a material selected from the group consisting of: ruthenium, copper, cobalt, molybdenum, tungsten, aluminum, or rhodium.
8 . A method of forming an interconnect structure, the method comprising:
forming a source drain contact from a single continuous metal layer, wherein a top region of the source drain contact is recessed;
covering the recessed, top region of the source drain contact with a cap; and
forming a via above and contacting the source drain contact, wherein the via comprises an extended contact region into the cap over the source drain contact.
9 . The method of claim 8 , wherein a sidewall of the extended contact region directly contacts a sidewall of the cap.
10 . The method of claim 8 , wherein an uppermost surface of the extended contact region of the via is in direct contact with and substantially parallel to a lower surface of an interlayer dielectric.
11 . The method of claim 10 , wherein the cap is below and contacting the interlayer dielectric.
12 . The method of claim 8 , wherein a thickness of the cap is equal or substantially equal to a thickness of the extended contact region.
13 . The method of claim 8 , wherein the cap is composed of a material selected from the group consisting of: aluminum oxide, titanium oxide, hafnium silicate, zirconium silicate, hafnium dioxide, and zirconium dioxide.
14 . The method of claim 8 , wherein the source drain contact and the via are composed of a material selected from the group consisting of: ruthenium, copper, cobalt, molybdenum, tungsten, aluminum, or rhodium.