Patent ID: 9269529
Filing Date: 2016-02-23
CPC Classification: H01J,H01L

Claim Text:
1. A method for performing DA (Dynamic Alignment) beam calibration in a plasma processing system, said method comprising: acquiring a positional difference between a wafer and an end effector, said positional difference is acquired using an optical imaging approach, said optical imaging approach comprising: positioning the wafer on the end effector of a robot arm, taking a still image of said wafer on said end effector with an image acquisition device, determining a center of said wafer and said end effector-defined center of said end effector by processing said still image with a processing unit, determining said positional difference between said center of said wafer and said end effector-defined center with the processing unit, centering said wafer with respect to said end effector by compensating for said positional difference between said center of said wafer and said end effector-defined center with robot movement compensation of the robot arm, moving said wafer and said end effector through DA beams associated with a plasma processing module; and obtaining a reference DA beam pattern with the processing unit by recording a break-and-make pattern of said DA beams, said break-and-make pattern occurring as said wafer and said end effector move through said DA beams, wherein a single visual indicator is located on said end effector, said visual indicator representing a reference mark, said processing unit deriving said end effector-defined center by using the reference mark; wherein said still image includes both said visual indicator and a portion of said wafer, wherein said visual indicator is a scribe line, said scribe line configured to be an arc of a circle such that the center of said circle coincides with said end effector-defined center.