Process control for atmospheric plasma treatment of surfaces
OwnerSteven R. Waltherinventor
Life of this patent
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Abstract
Disclosed is a system and method for delivering reactive species from a plasma to a treatment area by scanning a linear array of stacked plasma elements across the treatment area. Reactive species output from each plasma element is calibrated, and during scanning each plasma element is modulated with a uniformity modulation and a dose modulation, enabling a predetermined contour dose distribution of reactive species to be delivered to the treatment area.
Claims29
A method of delivering a predetermined dose distribution of reactive species from a plasma to a treatment area with a predetermined treatment boundary, the method comprising the steps of:
- providing a plasma array, the plasma array comprising a linear array of at least two plasma elements stacked linearly along an array axis, wherein each plasma element is an atmospheric plasma source and wherein each plasma element has an on state producing a reactive species output and an off state wherein the reactive species output is zero;
- performing a calibration measurement, wherein the calibration measurement comprises:
- activating the plasma elements to produce the reactive species output;
- measuring a reactive species concentration for each one of the plasma elements;
- and,
- deriving an element scaling factor for each one of the plasma elements, wherein each element scaling factor is inversely proportional to the corresponding reactive species concentration;
- scanning the plasma array across the treatment area with one or more scans in a back-and-forth scan direction perpendicular to the array axis;
- and,
- controlling each plasma element during the scanning with a uniformity modulation and a dose modulation, wherein the uniformity modulation controls the reactive species concentration of each plasma element to be proportional to the corresponding element scaling factor, and wherein the dose modulation controls the on state and the off state of each plasma element to deliver the predetermined dose distribution.
A system configured to deliver a predetermined dose distribution of reactive species from a plasma to a treatment area with a predetermined treatment boundary, the system comprising:
- a plasma array, the plasma array comprising a linear array of at least two plasma elements stacked linearly along an array axis, wherein each plasma element is a cold atmospheric plasma (CAP) source and wherein each plasma element has an on state producing a reactive species output and an off state wherein the reactive species output is zero;
- a system controller comprising a uniformity controller and a dose controller;
- an empirical calibration system configured to couple the reactive species output to a test surface comprising a material which is reactive with the reactive species and to measure a reaction rate with the test surface of the reactive species output from each plasma element;
- and,
- a scan system configured to perform a scanning of the plasma array across the treatment area with one or more scans in a back-and-forth scan direction perpendicular to the array axis;
- wherein the uniformity controller controls each plasma element during the scanning with a uniformity modulation wherein the reactive species output of each plasma element is inversely proportional to the corresponding reaction rate, and wherein the dose controller controls each plasma element during the scanning with a dose modulation wherein the on state and the off state of each plasma element are controlled to deliver the predetermined dose distribution.
Dependencies are inferred from the claim text.