Plasma source and method for removing materials from substrates utilizing pressure waves
In a method is provided for removing a material from a substrate, a plasma is generated at atmospheric pressure. The plasma includes an energetic species reactive with one or more components of the material. The plasma is flowed from an outlet as a plasma plume that includes periodic regions of high plasma density and low plasma density. The material is exposed to the plasma plume. At least one component of the material reacts with the energetic species, and at least one other component of the material is physically impacted and moved by one or more of the regions of high plasma density.
1. An atmospheric pressure plasma source comprising:
a plasma-generating chamber for generating atmospheric pressure, non-thermal plasma, wherein the plasma-generating chamber defines an interior space including a plasma-generating region;
a gas inlet for providing a flow path for plasma-generating gas to feed into the plasma-generating region;
a powered electrode extending into the interior space of the plasma-generating chamber, wherein the powered electrode is at least partially within the plasma-generating region, configured to outlet the plasma to outside the plasma-generating chamber, wherein the powered electrode causes an electrical field to impress between the powered electrode and the plasma-generating chamber for generating vibrations of the plasma-generating chamber, wherein the vibrations are transferred to the plasma within the plasma-generating chamber for generating pressure waves in a plasma plume outlet from the plasma-generating chamber; and
a plasma outlet communicating with the plasma-generating chamber for outletting the plasma plume.
2. The atmospheric pressure plasma source of claim 1 , wherein the flowing means is configured for producing pressure waves in the plasma plume.
3. The atmospheric pressure plasma source of claim 2 , wherein the pressure waves are shock waves.
4. The atmospheric pressure plasma source of claim 1 , wherein the flowing means comprises a power source communicating with the electrode and configured for enabling adjustment of a drive frequency and a power level applied to the electrode to produce pressure waves in the plasma plume.
5. The atmospheric pressure plasma source of claim 1 , wherein the flowing means is configured for flowing the plasma plume at a supersonic velocity and at a pressure different from an ambient pressure outside the plasma outlet.
6. The atmospheric pressure plasma source of claim 1 , wherein the flowing means comprises a converging-diverging nozzle and the plasma outlet is an exit of the nozzle.
7. The atmospheric pressure plasma source of claim 1 , wherein the flowing means comprises a piezoelectric element disposed in the chamber and configured for transferring vibrations to plasma generated in the chamber.
8. The atmospheric pressure plasma source of claim 1 , wherein the flowing means comprises an air supply source configured for supplying air to the chamber at a pressure of 30-110 psi and at a flow rate of 1-7.5 CFM, and a converging nozzle, and wherein the plasma outlet is an exit of the nozzle.
9. An atmospheric pressure plasma source, comprising:
a plasma-generating chamber;
an electrode extending into the plasma-generating chamber;
a converging nozzle communicating with the plasma-generating chamber; and
an air supply source configured for supplying air to the chamber at a pressure of 30-110 psi and at a flow rate of 1-7.5 CFM.
10. The atmospheric pressure plasma source of claim 9 , comprising a power source communicating with the electrode and configured for enabling adjustment of a drive frequency and a power level applied to the electrode to modulate pressure waves produced in a plasma plume flowing from the converging nozzle.