Minimizing radical recombination using ALD silicon oxide surface coating with intermittent restoration plasma
Methods and apparatus for remote plasma processing are provided. In various embodiments, a reaction chamber is conditioned by forming a low recombination material coating on interior chamber surfaces. The low recombination material helps minimize the degree of radical recombination that occurs within the reaction chamber when the reaction chamber is used to process substrates. During processing on substrates, the low recombination material may become covered by relatively higher recombination material (e.g., as a byproduct of the substrate processing), which results in a decrease in the amount of radicals available to process the substrate over time. The low recombination material coating may be reconditioned through exposure to an oxidizing plasma, which acts to reform the low recombination material coating. The reconditioning process may occur periodically as additional processing occurs on substrates.
1. A method of conditioning a reaction chamber used to perform remote plasma processing, the method comprising:
forming a low recombination material coating on exposed surfaces within the reaction chamber through an atomic layer deposition process while no substrate is present in the reaction chamber; and
after performing a remote plasma operation on one or more substrates, exposing the reaction chamber to an oxidizing plasma to recondition the exposed surfaces within the reaction chamber and thereby reform the low recombination material coating.
2. The method of claim 1 , further comprising after forming the low recombination material coating, performing the remote plasma operation to process one or more substrates in the reaction chamber, wherein the remote plasma operation results in formation of a second coating on at least a portion of the exposed surfaces within the reaction chamber, the second coating promoting a higher rate of radical recombination during the remote plasma operation than the low recombination material coating.
3. The method of claim 2 , wherein exposing the reaction chamber to the oxidizing plasma modifies the second coating to reform the low recombination material coating.
4. The method of claim 3 , wherein the low recombination material coating comprises silicon oxide, wherein performing the remote plasma operation comprises depositing a silicon-containing film on the one or more substrates, and wherein the second coating comprises a silicon-containing material.
5. The method of claim 3 , wherein one or more substrates are present in the reaction chamber when the reaction chamber is exposed to the oxidizing plasma.
6. The method of claim 5 , further comprising:
after exposing the reaction chamber to the oxidizing plasma while the substrate is in the reaction chamber, performing a second remote plasma operation to further process the substrate in the reaction chamber, the second remote plasma operation again resulting in formation of the second coating; and
after performing the second remote plasma operation, exposing the reaction chamber to a second oxidizing plasma while the substrate is present in the reaction chamber to again recondition the exposed surfaces within the reaction chamber to modify the second coating to reform the low recombination material coating.
7. The method of claim 2 , wherein performing the remote plasma operation comprises:
providing one of the one or more substrates in the reaction chamber,
flowing a silicon-containing reactant into the reaction chamber without exposing the silicon-containing reactant to an in situ plasma,
generating a hydrogen plasma in a remote plasma chamber, the remote plasma chamber being positioned proximate the reaction chamber and separated from the reaction chamber by a showerhead, and allowing the hydrogen plasma to pass through the showerhead into the reaction chamber while the silicon-containing reactant is flowed into the reaction chamber;
exposing the substrate to the silicon-containing reactant and the hydrogen plasma concurrently to deposit a silicon-containing film on the substrate.
8. The method of claim 3 , further comprising:
cleaning the reaction chamber to remove any low recombination material coating and second coating present on the exposed surfaces within the reaction chamber, the cleaning comprising exposing the reaction chamber to a fluorine-containing plasma; and
after cleaning the reaction chamber, repeating the method of claim 1 .
9. The method of claim 1 , wherein the reaction chamber is exposed to the oxidizing plasma for a duration between about 0.05-5 seconds.
10. The method of claim 9 , wherein the duration is between about 0.1-1 seconds.
11. The method of claim 1 , wherein the atomic layer deposition process for forming the low recombination material coating on exposed surfaces within the reaction chamber comprises:
(a) flowing a first reactant into the reaction chamber and allowing the first reactant to adsorb onto exposed surfaces within the reaction chamber;
(b) purging the first reactant from the reaction chamber;
(c) flowing a second reactant into the reaction chamber;
(d) exposing the exposed surfaces within the reaction chamber to plasma to drive a surface reaction between the first reactant and the second reactant to form a low recombination material coating on the exposed surfaces within the reaction chamber; and
(e) repeating (a)-(d) until the low recombination material coating reaches a final coating thickness.
12. The method of claim 11 , wherein the low recombination material coating comprises silicon oxide.
13. The method of claim 11 , wherein at least one of the first and second reactants flows into the reaction chamber from a remote plasma chamber, the remote plasma chamber being located proximate the reaction chamber and separated from the reaction chamber by a showerhead.
14. The method of claim 13 , wherein both the first and second reactants flow into the reaction chamber from the remote plasma chamber, and wherein the oxidizing plasma is generated in the remote plasma chamber and flows into the reaction chamber through the showerhead.
15. The method of claim 1 , wherein the oxidizing plasma is generated in situ in the reaction chamber.
16. The method of claim 1 , further comprising cyclically repeating the steps of (a) performing a remote plasma operation on one or more substrates and (b) exposing the reaction chamber to the oxidizing plasma to recondition the exposed surfaces within the reaction chamber, wherein between about 1-50 substrates are processed in (a) between each iteration of step (b).
17. The method of claim 1 , further comprising performing the remote plasma operation on one or more substrates, the remote plasma operation comprising:
providing one of the one or more substrates in the reaction chamber,
flowing a silicon-containing reactant into the reaction chamber without exposing the silicon-containing reactant to an in situ plasma,
generating a hydrogen plasma in a remote plasma chamber, the remote plasma chamber being positioned proximate the reaction chamber and separated from the reaction chamber by a showerhead, and allowing the hydrogen plasma to pass through the showerhead into the reaction chamber while the silicon-containing reactant is flowed into the reaction chamber;
exposing the substrate to the silicon-containing reactant and the hydrogen plasma concurrently to deposit a silicon-containing film on the substrate.
18. The method of claim 1 , wherein the low recombination material coating is formed at a thickness between about 50-500 Å, as measured by an average thickness of the low recombination material coating on a substrate support within the reaction chamber.
19. The method of claim 1 , wherein the low recombination material coating comprises silicon oxide, the method further comprising performing the remote plasma operation on the one or more substrates by exposing the one or more substrates to a remote plasma to thereby deposit silicon carbide, silicon nitrocarbide, or silicon oxycarbide on the one or more substrates,
wherein performing the remote plasma operation forms silicon carbide, silicon nitrocarbide, or silicon oxycarbide on the exposed surfaces within the reaction chamber, and
wherein exposing the reaction chamber to the oxidizing plasma reforms the low recombination material coating by oxidizing the silicon carbide, silicon nitrocarbide, or silicon oxycarbide on the exposed surfaces within the reaction chamber, thereby reforming silicon oxide on the exposed surfaces within the reaction chamber.