Angular averaging calibration on bare wafer metrology tools for ESFQR matching improvement

A non-transitory computer-readable medium, storing program instructions executable on a computer system for performing a computer-implemented method for generating a tool correction map, wherein the computer-implemented method comprises:

• measuring surface heights of front and back sides of first and second calibration wafers at multiple wafer rotation angles with a metrology subsystem, wherein the first and second calibration wafers are low-shape wafers having opposite shapes from each other as seen by the metrology subsystem;
• generating a first correction map from the measured surface heights of the front and back sides of the first calibration wafer at the multiple wafer rotation angles;
• generating a second correction map from the measured surface heights of the front and back sides of the second calibration wafer at the multiple wafer rotation angles;
• generating a tool correction map by averaging the first and second correction maps;
• and
• storing the tool correction map for use in calibrating a thickness map of a test wafer generated from surface heights of front and back sides of the test wafer measured by the metrology subsystem.

A computer-implemented method for generating a tool correction map, comprising:

• measuring surface heights of front and back sides of first and second calibration wafers at multiple wafer rotation angles with a metrology subsystem, wherein the first and second calibration wafers are low-shape wafers having opposite shapes from each other as seen by the metrology subsystem;
• generating a first correction map from the measured surface heights of the front and back sides of the first calibration wafer at the multiple wafer rotation angles;
• generating a second correction map from the measured surface heights of the front and back sides of the second calibration wafer at the multiple wafer rotation angles;
• generating a tool correction map by averaging the first and second correction maps;
• and
• storing the tool correction map for use in calibrating a thickness map of a test wafer generated from surface heights of front and back sides of the test wafer measured by the metrology subsystem, wherein generating the first correction map, the second correction map, and the tool correction map and storing the tool correction map are performed by a computer subsystem.