CMOS silicide metal gate integration
View Patent ↗The present invention provides a complementary metal oxide semiconductor integration process whereby a plurality of silicided metal gates are fabricated atop a gate dielectric. Each silicided metal gate that is formed using the integration scheme of the present invention has the same silicide metal phase and substantially the same height, regardless of the dimension of the silicide metal gate. The present invention also provides various methods of forming a CMOS structure having silicided contacts in which the polySi gate heights are substantially the same across the entire surface of a semiconductor structure.
1. A method of forming a CMOS structure having silicide contacts comprising the step of:
providing a structure comprising a plurality of polySi gates overlying a semiconductor substrate;
depositing a silicide metal atop the structure including the polySi gates and the semiconductor substrate;
forming a recessed, reflow material between each polySi gate;
removing silicide metal from atop each of the polySi gates;
removing the recessed, reflow material; and
annealing the structure so as to form silicide contact regions between each of the polySi gates.
2. The method of claim 1 wherein the silicide metal comprises Ti, Ta, W, Co, Ni, Pt, Pd or alloys thereof.
3. The method of claim 2 wherein the metal is Co, Ni or Pt.
4. The method of claim 1 wherein the recessed, reflow material comprises an antireflective coating or a spin-on dielectric.
5. The method of claim 1 wherein the forming the recessed, reflow material comprises deposition and optional etching.
6. The method of claim 1 wherein the removing the silicide metal comprises a wet etching process.
7. The method of claim 1 wherein the annealing includes at least a first annealing step which is performed at a temperature from about 300° C. to about 600° C.
8. The method of claim 7 further comprising an optional second annealing step which is performed at a temperature from about 600° C. to about 800° C.
9. The method of claim 1 further comprising forming silicide metal gates by depositing and planarizing a capping bilayer comprising SiO 2 and Si 3 N 4 ; performing an optional wet etch process to remove SiO 2 ; performing a selective RIE process to remove Si 3 N 4 atop the gate; forming a silicide metal on the gate; and performing a salicide process.