US Patent Issued to KLA on Jan. 20 for "Angular averaging calibration on bare wafer metrology tools for ESFQR matching improvement" (Singaporean Inventor)

ALEXANDRIA, Va., Jan. 20 -- United States Patent no. 12,529,552, issued on Jan. 20, was assigned to KLA Corp. (Milpitas, Calif.).

"Angular averaging calibration on bare wafer metrology tools for ESFQR matching improvement" was invented by Haifeng Wang (Singapore).

According to the abstract* released by the U.S. Patent & Trademark Office: "Methods and systems for generating a tool correction map are provided. One method includes measuring surface heights of front and back sides of first and second calibration wafers at multiple wafer rotation angles. The calibration wafers are low-shape wafers which show opposite shapes from each other when seen by the measurement apparatus, or they could be a single wafer but it is flipped in the measurem...