Self-aligned barrier and capping layers for interconnects
An interconnect structure for integrated circuits for copper wires in integrated circuits and methods for making the same are provided. Mn, Cr, or V containing layer forms a barrier against copper diffusing out of the wires, thereby protecting the insulator from premature breakdown, and protecting transistors from degradation by copper. The Mn, Cr, or V containing layer also promotes strong adhesion between copper and insulators, thus preserving the mechanical integrity of the devices during manufacture and use, as well as protecting against failure by electromigration of the copper during use of the devices and protecting the copper from corrosion by oxygen or water from its surroundings. In forming such integrated circuits, certain embodiments of the invention provide methods to selectively deposit Mn, Cr, V, or Co on the copper surfaces while reducing or even preventing deposition of Mn, Cr, V, or Co on insulator surfaces. Catalytic deposition of copper using a Mn, Cr, or V containing precursor and an iodine or bromine containing precursor is also provided.
1. A process for forming an integrated circuit interconnect structure, said process comprising:
a) providing a partially-completed and planarized interconnect structure comprising an electrically insulating surface and an electrically conductive, copper-containing surface;
b) depositing a protecting agent that comprises two or more compounds, each compound having one or more dialkylamide groups bonded to silicon, over said electrically insulating surface to synergistically reduce affinity of said electrically insulating surface to a precursor comprising manganese, cobalt, chromium or vanadium;
c) selectively depositing a metal selected from the group consisting of manganese, cobalt, chromium and vanadium on at least a part of the electrically conductive copper-containing surface.
2. The process as in claim 1 , wherein said selectively depositing a metal is carried out by CVD or ALD.
3. The process as in claim 1 , wherein said protecting agent reduces reactivity of said insulating surface with said precursor comprising manganese.
4. The process as in claim 1 , wherein said protecting agent reduces reactivity of said insulating surface with said precursor comprising cobalt.
5. The process as in claim 1 , wherein said protecting agent reduces reactivity of said insulating surface with said precursor comprising chromium.
6. The process as in claim 1 , wherein said protecting agent reduces reactivity of said insulating surface with said precursor comprising vanadium.
7. The process as in claim 1 , wherein said protecting agent is selectively deposited on said electrically insulating surface.
8. The process as in claim 1 , wherein the compounds with one or more dialkylamide groups bonded to silicon comprise bis(N,N-dialkylamino)dialkylsilanes and (N,N-dialkylamino)trialkylsilanes.