Methods of forming metal chalcogenide pillars
Methods of producing a self-aligned structure comprising a metal chalcogenide are described. Some methods comprise forming a metal-containing film in a substrate feature and exposing the metal-containing film to a chalogen precursor to form a self-aligned structure comprising a metal chalcogenide. Some methods comprise forming a metal-containing film in a substrate feature, expanding the metal-containing film to form a pillar and exposing the pillar to a chalogen precursor to form a self-aligned structure comprising a metal chalcogenide. Some methods comprise directly forming a metal chalcogenide pillar in a substrate feature to form a self-aligned structure comprising a metal chalcogenide. Methods of forming self-aligned vias are also described.
1. A substrate processing method comprising:
forming a metal film on a substrate with a top surface with at least one feature formed therein, the at least one feature extending a distance into the substrate from the top surface and having a sidewall and bottom, the metal film formed in the at least one feature; and
exposing the metal film to a chalcogen precursor to form a metal chalcogenide pillar which has sidewalls above the top surface that are substantially coplanar with the sidewalls of the at least one feature, the chalcogen precursor comprising substantially no oxygen.
2. The method of claim 1 , wherein the metal comprises one or more of tungsten and molybdenum.
3. The method of claim 1 , wherein the chalcogen precursor comprises one or more of H 2 S, alkyl sulfides, alkyl disulfides, S 8 powder and Se powder.
4. The method of claim 1 , wherein the metal chalcogenide pillar comprises one or more of sulfur, selenium, or tellurium.
5. The method of claim 1 , wherein the metal chalcogenide pillar is orthogonal to the top surface.
6. The method of claim 1 , wherein a volumetric ratio of the metal chalcogenide pillar to the metal film is greater than or equal to about 2.
7. A method for producing self-aligned vias, the method comprising:
forming a metal chalcogenide pillar according to claim 1 ;
depositing a dielectric material on the top surface, the dielectric material surrounding the metal chalcogenide pillar; and
removing the metal chalcogenide pillar to leave a via through the dielectric material.
8. A substrate processing method comprising:
forming a metal film on a substrate with a substrate surface with at least one feature formed therein, the at least one feature extending a distance into the substrate from the substrate surface and having a sidewall and bottom, the metal film formed in the at least one feature;
exposing the metal film to a reactant to expand the material volume of the metal film and form a pillar which grows straight up from the at least one feature, the pillar comprising substantially no oxygen; and
exposing the pillar to a chalcogen precursor to form a metal chalcogenide pillar, the chalcogen precursor comprising substantially no oxygen.
9. The method of claim 8 , wherein the metal comprises one or more of tungsten and molybdenum.
10. The method of claim 8 , wherein the pillar comprises one or more of nitrogen, carbon or silicon.
11. The method of claim 8 , wherein the chalcogen precursor comprises one or more of H 2 S, dialkyl disulfides, S 8 powder and Se powder.
12. The method of claim 8 , wherein the metal chalcogenide pillar comprises one or more of sulfur, selenium, or tellurium.
13. The method of claim 8 , wherein the metal chalcogenide pillar is orthogonal to the substrate surface.
14. A method for producing self-aligned vias, the method comprising:
forming a metal chalcogenide pillar according to claim 8 ;
depositing a dielectric material on the substrate surface, the dielectric material surrounding the metal chalcogenide pillar; and
removing the metal chalcogenide pillar to leave a via through the dielectric material.
15. A substrate processing method comprising:
exposing a substrate to a metal chalcogenide precursor to form a metal chalcogenide pillar, the substrate having a top surface with at least one feature formed therein, the at least one feature extending a distance into the substrate from the top surface and having a sidewall and bottom, the metal chalcogenide pillar growing straight up from the at least one feature and comprising substantially no oxygen.
16. The method of claim 15 , wherein the metal chalcogenide pillar comprises one or more of tungsten and molybdenum.
17. The method of claim 15 , wherein the metal chalcogenide pillar comprises one or more of sulfur, selenium, or tellurium.
18. A method for producing self-aligned vias, the method comprising:
forming a metal chalcogenide pillar according to claim 15 ;
depositing a first material comprising a dielectric on the top surface, the first material surrounding the metal chalcogenide pillar; and
removing the metal chalcogenide pillar to leave a via through the first material.
19. The method of claim 15 , wherein the metal chalcogenide precursor is represented by the general formula (R 4 N)xMaZy, where each R is independently H or C1-C4 alkyl, M is a metal, Z is a chalcogen and x, y, and a are integers from 1 to 6 such that the metal chalcogenide precursor is electrochemically neutral.
20. The method of claim 19 , wherein the metal chalcogenide precursor comprises bis-tetraalkylammonium tetrathiotungstate ((R 4 N) 2 WS 4 ), where R is a C1-4 alkyl group.