Method of selective film deposition for forming fully self-aligned vias
A substrate processing method for forming fully self-aligned vias. The method may be performed in a batch processing system that is capable of simultaneously processing multiple substrates, where the batch processing system includes a process chamber containing processing spaces defined around an axis of rotation in the process chamber. Each of the substrates contain a first surface and a second surface, and the method includes selectively forming SiO 2 raised features on the first surface relative to the second surface.
1. A substrate processing method, comprising:
a) arranging substrates on a plurality of substrate supports in a process chamber, wherein the process chamber contains processing spaces defined around an axis of rotation in the process chamber, each of the substrates containing a first surface and a second surface;
b) rotating the plurality of substrate supports about the axis of rotation;
c) exposing the substrates to a reactant gas containing a metal-containing catalyst;
d) exposing the substrates to a cleaning gas that removes an oxidized layer from the second surface along with the metal-containing catalyst on the oxidized layer;
e) exposing the substrates to a deposition gas containing a silanol gas for a time period that selectively deposits an initial SiO 2 film on the metal-containing catalyst on the first surface, wherein the initial SiO 2 film forms a raised feature adjacent the second surface;
f) exposing the substrates to the reactant gas to selectively coat the raised feature of the initial SiO 2 film, but not the second surface, with the metal-containing catalyst; and
g) exposing the substrates to the deposition gas containing the silanol gas for a time period that selectively deposits an additional SiO 2 film on the metal-containing catalyst on the raised feature of the initial SiO 2 film.
2. The method of claim 1 , wherein the first surface includes a dielectric material and the second surface includes a metal layer.
3. The method of claim 1 , further comprising:
before performing step f), repeating steps c)-e) at least once to increase the thickness of the initial SiO 2 film.
4. The method of claim 1 , further comprising:
repeating steps f) and g) at least once to increase the thickness of the additional SiO 2 film on the initial SiO 2 film.
5. The method of claim 1 , wherein steps f) and g) are performed without an intervening step of exposing the substrates to the cleaning gas.
6. The method of claim 1 , wherein the reactant gas includes aluminum (Al), titanium (Ti), hafnium (Hf), zirconium (Zr), or a combination thereof.
7. The method of claim 1 , wherein the reactant gas includes trimethylaluminum (AlMe 3 ).
8. The method of claim 1 , wherein the exposing the substrate to the deposition gas containing the silanol gas is performed in the absence of any oxidizing and hydrolyzing agent at a substrate temperature of approximately 150° C., or less.
9. The method of claim 1 , wherein the substrate temperature is about 100° C., or less, during the exposing steps.
10. The method of claim 1 , wherein the deposition gas consists of the silanol gas and an inert gas.
11. The method of claim 1 , wherein the silanol gas is selected from the group consisting of tris(tert-pentoxy) silanol, tris(tert-butoxy) silanol, and bis(tert-butoxy)(isopropoxy) silanol.
12. The method of claim 1 , wherein the initial and additional SiO 2 films are deposited on the metal-containing catalyst in a self-limiting process.
13. The method of claim 1 , wherein a thickness of the initial SiO 2 film is about 15 nm or less.
14. The method of claim 1 , wherein the initial SiO 2 film deposited by sequentially performing steps c)-e) only once.
15. The method of claim 1 , wherein the thickness of the additional SiO 2 film is between about 50 nm and about 100 nm.
16. The method of claim 1 , wherein the cleaning gas includes an alcohol.
17. The method of claim 16 , wherein the alcohol includes isopropyl alcohol, methanol, or ethanol.
18. The method of claim 1 , wherein steps c)-e) include injecting the reactant gas into a first processing space defined by a first included angle about the axis of rotation;
exposing the first and second surfaces of each of the substrates to the reactant gas in the first processing space during each full rotation;
injecting the cleaning gas into a second processing space defined by a second included angle about the axis of rotation and separated from the first processing space;
exposing the first and second surfaces of each of the substrates to the cleaning gas during each full rotation; and
injecting the deposition gas containing the silanol gas into a third processing space defined by a third included angle about the axis of rotation and separated from the first and second processing spaces.
19. The method of claim 18 , further comprising
re-exposing the first and second surfaces of each of the substrates to the reactant gas, cleaning gas, and deposition gas by repeatedly rotating the substrates through the first, second, and third processing spaces for incrementally depositing the initial SiO 2 film on each of the substrates.
20. The method of claim 1 , wherein steps f)-g) include
injecting the reactant gas into a first processing space defined by a first included angle about the axis of rotation;
exposing the first surfaces of each of the substrates to the reactant gas in the first processing space during each full rotation;
injecting the deposition gas containing the silanol gas into a second processing space defined by a second included angle about the axis of rotation and separated from the first processing space; and
re-exposing the first and second surfaces of each of the substrates to the reactant gas and the deposition gas by repeatedly rotating the substrates through the first and second processing spaces for incrementally depositing the additional SiO 2 film on each of the substrates.