Arrangements and methods for determining positions and offsets

摘要

A method for determining positions and offsets in a plasma processing system, the plasma processing system including at least a chuck and an upper electrode is provided. The method including moving a traversing assembly along a first plurality of paths to generate a first plurality of data sets, the traversing assembly including at least a light source, the light source providing a light beam, moving the traversing assembly along each path of the first plurality of paths causing the light beam to traverse the chuck and resulting in one or more data sets of the first plurality of data sets. The method also including receiving the first plurality of data sets and analyzing the first plurality of data sets to identify a first set of at least three discontinuities, wherein the first set of at least three discontinuities are related to three or more reflected light signals generated when the light beam encounters an edge of the chuck. The method also including determining a center of the chuck using coordinate data associated with the first set of at least three discontinuities.

主权项

1. A method for determining positions and offsets in a plasma processing system, said plasma processing system including a chuck and an upper electrode, said method comprising:
moving a traversing assembly including a light source providing a light beam along a first plurality of paths to cause said light beam to traverse said chuck and to generate one or more data sets of a first plurality of data sets; analyzing said one or more data sets of said first plurality of data sets to identify a first set of at least three discontinuities that are related to three or more reflected light signals generated when said light beam encounters an edge of said chuck; determining a center of said chuck using coordinate data associated with said first set of at least three discontinuities; determining a first set of three or more coordinate data points based on said first set of at least three discontinuities; determining said center of said chuck and an absolute position of said chuck based on said first set of three or more coordinate data points; moving said traversing assembly along a second plurality of paths to cause at least one of said light beam and a second light beam to traverse said upper electrode and resulting in one or more data sets of a second plurality of data sets; analyzing said one or more data sets of said second plurality of data sets to identify a second set of at least three discontinuities representing three or more points on said edge of said upper electrode; determining a center of said upper electrode using coordinate data associated with said second set of at least three discontinuities; positioning an optical calibration fixture in a pre-defined location, wherein said first plurality of paths traverse said pre-defined location, and wherein said optical calibration fixture has a plurality of calibration regions; and moving said traversing assembly along each path of said first plurality of paths causing said light beam to traverse said optical calibration fixture and resulting in one or more data sets of a third plurality of data sets, wherein said third plurality of data sets represent a measured reflectivity change of each calibration region of said plurality of calibration regions.