Plasma parameters and skew characterization by high speed imaging
Embodiments of the present disclosure relate to a method and an apparatus for monitoring plasma behavior inside a plasma processing chamber. In one example, a method for monitoring plasma behavior includes acquiring at least one image of a plasma, and determining a plasma parameter based on the at least one image.
1. A method for monitoring plasma characteristics in a plasma processing chamber, the method comprising:
performing a first plasma process in a processing chamber at a first processing condition;
acquiring at least one image of a first plasma of the first plasma process while extinguishing the plasma;
determining a plasma parameter of the first plasma based on the at least one image, the determining the plasma parameter comprising determining a termination direction of the first plasma while extinguishing the first plasma;
modifying the first processing condition to a second processing condition for a second plasma process in response to the determined plasma parameter;
performing the second plasma process in the processing chamber at the second processing condition, the second processing condition selected such that a second plasma of the second plasma process extinguishes in a center-to-edge direction; and
extinguishing the second plasma of the second plasma process.
2. The method of claim 1 further comprising:
acquiring a second image of the plasma under the second processing condition.
3. The method of claim 1 , wherein acquiring the at least one image occurs through a first lens placed in an aperture and one of a plurality of gas-passage holes formed on a ring-shaped liner disposed within the processing chamber.
4. The method of claim 3 , wherein the first lens placed in the aperture is a wide angle lens with a focal length of about 5 mm to about 6 mm.
5. The method of claim 3 , wherein acquiring the at least one image further comprises:
observing the plasma through a viewport formed in the processing chamber, the viewport coupled to the aperture and aligned with the first lens.
6. The method of claim 5 , wherein observing the plasma through the viewport further comprises:
viewing the plasma through at least one additional lens aligned with the first lens.
7. The method of claim 3 , wherein acquiring the at least one image further comprises:
capturing images of the plasma with a camera, a first lens of the camera aligned with the first lens placed in the aperture.
8. The method of claim 7 , wherein the camera has an image capture rate of at least 50,000 frames per second.
9. A method for monitoring plasma characteristics in a plasma processing chamber, the method comprising:
performing a first plasma process in a processing chamber at a first processing condition;
acquiring at least one image of a first plasma of the first plasma process while extinguishing the plasma, the acquiring occurring through a first lens placed on an aperture coupled to one of a plurality of gas-passage holes formed on a ring-shaped liner disposed within the processing chamber;
determining a plasma parameter of the first plasma based on the at least one image, the determining the plasma parameter comprising determining a termination direction of the first plasma while extinguishing the first plasma;
modifying the first processing condition to a second processing condition for a second plasma process in response to the determined plasma parameter;
performing the second plasma process in the processing chamber at the second processing condition, the second processing condition selected such that a second plasma of the second plasma process extinguishes in a center-to-edge direction; and
extinguishing the second plasma of the second plasma process.
10. A method for monitoring plasma characteristics in a plasma processing chamber, the method comprising:
performing a first plasma process in a processing chamber at a first processing condition;
acquiring a plurality of images capturing a collapse and termination of a first plasma of the first plasma process;
determining a plasma parameter of the first plasma based on at least one of the plurality of images, the determining the plasma parameter comprising determining a termination direction of the first plasma while extinguishing the first plasma;
modifying the first processing condition to a second processing condition for a second plasma process in response to the determined plasma parameter;
performing the second plasma process in the processing chamber at the second processing condition, the second processing condition selected such that a second plasma of the second plasma process extinguishes in a center-to-edge direction; and
extinguishing the second plasma of the second plasma process.