Electroless deposition process on a silicon contact
Embodiments as described herein provide methods for depositing a material on a substrate during electroless deposition processes, as well as compositions of the electroless deposition solutions. In one embodiment, the substrate contains a contact aperture having an exposed silicon contact surface. In another embodiment, the substrate contains a contact aperture having an exposed silicide contact surface. The apertures are filled with a metal contact material by exposing the substrate to an electroless deposition process. The metal contact material may contain a cobalt material, a nickel material, or alloys thereof. Prior to filling the apertures, the substrate may be exposed to a variety of pretreatment processes, such as preclean processes and activations processes. A preclean process may remove organic residues, native oxides, and other contaminants during a wet clean process or a plasma etch process. Embodiments of the process also provide the deposition of additional layers, such as a capping layer.
1. A composition of an activation solution, comprising:
a cobalt source at a concentration within a range from about 1 mM to about 100 mM;
a fluoride source at a concentration within a range from about 10 mM to about 400 mM; and
a hypophosphite source at a concentration within a range from about 5 mM to about 150 mM.
2. The composition of claim 1 , further comprising:
a cobalt source at a concentration within a range from about 5 mM to about 50 mM;
a fluoride source at a concentration within a range from about 20 mM to about 200 mM; and
a hypophosphite source at a concentration within a range from about 10 mM to about 80 mM.
3. The composition of claim 2 , further comprising:
the cobalt source at a concentration within a range from about 10 mM to about 30 mM;
the fluoride source at a concentration within a range from about 50 mM to about 120 mM; and
the hypophosphite source at a concentration within a range from about 20 mM to about 60 mM.
4. The composition of claim 3 , further comprising the cobalt source at a concentration of about 20 mM, the fluoride source at a concentration of about 80 mM, and the hypophosphite source at a concentration of about 40 mM.
5. The composition of claim 1 , wherein the fluoride source comprises hydrogen fluoride.
6. The composition of claim 5 , further comprising at least one alkanolamine compound.
7. The composition of claim 6 , further comprising at least two alkanolamine compounds.
8. The composition of claim 6 , wherein the at least one alkanolamine compound is selected from the group consisting of ethanolamine, diethanolamine, triethanolamine, derivatives thereof, and combinations thereof.
9. The composition of claim 8 , wherein a molar ratio of a first alkanolamine compound to a second alkanolamine compound is within a range from about 1 to about 5.
10. The composition of claim 9 , wherein the first alkanolamine compound is diethanolamine the second alkanolamine compound is triethanolamine.
11. The composition of claim 10 , wherein the molar ratio is about 1.2.
12. The composition of claim 1 , wherein the fluoride source has a chemical formula of [R 4 N][F], where each R is independently selected from the group consisting of hydrogen, an alkyl group, an alkanol group, derivatives thereof, and combinations thereof.
13. The composition of claim 12 , wherein the fluoride source has a chemical formula of [(HO(CH 2 ) n ) m NH 4-m ][F], where n=1, 2, 3, 4, or 5, and m=1, 2, 3, or 4.
14. The composition of claim 13 , wherein the fluoride source has a chemical formula of [(HOCH 2 CH 2 CH 2 ) m NH 4-m ][F], where m=1, 2, 3, or 4.
15. The composition of claim 1 , wherein the fluoride source is selected from the group consisting of ethanolammonium fluoride, diethanolammonium fluoride, triethanolammonium fluoride, tetramethylammonium fluoride, ammonium fluoride, hydrogen fluoride, salts thereof, derivatives thereof, and combinations thereof.
16. The composition of claim 15 , wherein the hypophosphite source is selected from the group consisting of sodium hypophosphite, potassium hypophosphite, ammonium hypophosphite, tetramethylammonium hypophosphite, salts thereof, derivatives thereof, and combinations thereof.