Defect control and stability of DC bias in RF plasma-based substrate processing systems using molecular reactive purge gas
A substrate processing system comprises an upper electrode and a lower electrode arranged in a processing chamber. A gas delivery system selectively delivers at least one of precursor, one or more deposition carrier gases and a post deposition purge gas. An RF generating system deposits film on the substrate by generating RF plasma in the processing chamber between the upper electrode and the lower electrode by supplying an RF voltage to one of the upper electrode and the lower electrode while the precursor and the one or more deposition carrier gases are delivered by the gas delivery system. A bias generating circuit selectively supplies a DC bias voltage to one of the upper electrode and the lower electrode while the post deposition purge gas is delivered by the gas delivery system. The post deposition purge gas that is delivered by the gas delivery system includes a molecular reactant gas.
1. A substrate processing system comprising:
an upper electrode and a lower electrode arranged in a processing chamber;
a pedestal arranged in the processing chamber, wherein the pedestal is configured to support a substrate during processing;
a gas delivery system configured to selectively deliver at least one of a precursor, one or more deposition carrier gases, and a post deposition purge gas;
an RF generating system configured to deposit film on the substrate by generating RF plasma in the processing chamber between the upper electrode and the lower electrode by supplying an RF voltage to one of the upper electrode and the lower electrode while the precursor and the one or more deposition carrier gases are delivered by the gas delivery system;
a bias generating circuit configured to selectively supply a DC bias voltage to the one of the upper electrode and the lower electrode;
a substrate movement system configured to move the substrate relative to the pedestal while the DC bias voltage is generated; and
a controller configured to:
control the bias generating circuit to supply the DC bias voltage to the one of the upper electrode and the lower electrode,
control the gas delivery system to supply the post deposition purge gas, and
control the substrate movement system to move the substrate relative to the pedestal while the DC bias voltage is generated,
wherein the post deposition purge gas that is delivered by the gas delivery system includes a molecular reactant gas.
2. The substrate processing system of claim 1 , wherein the post deposition purge gas does not include an inert gas.
3. The substrate processing system of claim 1 , wherein the post deposition purge gas is selected from one of the deposition carrier gases.
4. The substrate processing system of claim 1 , wherein the post deposition purge gas has a higher breakdown voltage than helium and argon over process pressures from 0.2 Torr to 6 Torr.
5. The substrate processing system of claim 1 , wherein a start of the DC bias voltage is initiated a first predetermined period before the RF plasma is extinguished or a second predetermined period after the RF plasma is extinguished.
6. The substrate processing system of claim 1 , wherein the substrate movement system includes a robot configured to move the substrate relative to the pedestal.
7. A substrate processing tool comprising:
N reactors each including the substrate processing system of claim 1 , where N is an integer greater than zero,
wherein the substrate movement system includes an indexing mechanism configured to index substrates between a plurality of stations within at least one of the N reactors while the DC bias voltage is generated.
8. The substrate processing system of claim 1 , wherein the bias generating circuit generates the DC bias voltage before the RF plasma is extinguished and ends the DC bias voltage before a subsequent RF plasma is struck.
9. The substrate processing system of claim 1 , wherein the bias generating circuit generates the DC bias voltage continuously except during a period when the RF plasma is struck.
10. The substrate processing system of claim 1 , wherein the RF generating system includes:
an RF generator to generate the RF voltage; and
a matching and distribution network in communication with the RF generator and the one of the upper electrode and the lower electrode.
11. The substrate processing system of claim 1 , wherein the film includes nitrogen-free anti-reflective film, the deposition carrier gases include carbon dioxide and helium, and the post deposition purge gas includes carbon dioxide.
12. The substrate processing system of claim 1 , wherein the film includes amorphous silicon, the one or more deposition carrier gases include molecular hydrogen and helium, and the post deposition purge gas includes molecular hydrogen.
13. The substrate processing system of claim 1 , wherein the film includes ashable hard mask, the one or more deposition carrier gases include molecular hydrogen and helium, and the post deposition purge gas includes molecular hydrogen.
14. The substrate processing system of claim 1 , wherein the film includes silicon nitride, the one or more deposition carrier gases include molecular nitrogen and ammonia, and the post deposition purge gas includes molecular nitrogen.
15. The substrate processing system of claim 1 , wherein the film includes silicon dioxide, the one or more deposition carrier gases include molecular nitrogen and nitrous oxide, and the post deposition purge gas includes molecular nitrogen.
16. The substrate processing system of claim 1 , wherein the film includes silicon oxycarbide, the one or more deposition carrier gases include carbon dioxide and helium, and the post deposition purge gas includes carbon dioxide.