Patent ID: 9431212
Filing Date: 2016-08-30
CPC Classification: G01N,G03F,H01J

Claim Text:
1. A method for predicting a performance of a photolithographic mask at a predetermined exposure wavelength, comprising: a. repeatedly scanning at least one electron beam with multiple beam energies across at least one portion of the photolithographic mask, wherein the performance of a photolithographic mask is defined by its capability to transmit a predetermined structure or pattern in a photoresist arranged on a wafer; b. measuring signals generated by the at least one electron beam interacting with the at least one portion of the photolithographic mask, wherein if the photolithographic mask includes a defect, the signals include a positional information of the defect; c. determining whether the defect is a defect of an absorber layer of the photolithographic mask or a defect of a multi-layer structure of the photolithographic mask, and, if the defect is a defect of the multi-layer structure of the photolithographic mask, predicting the performance of the at least one portion of the photolithographic mask at the predetermined exposure wavelength based on the measured signals; and d. determining whether a repair of the defect is required based on a discrepancy between the determined performance and a predetermined performance.