Method for determining the performance of a photolithographic mask
AssigneeCarl Zeiss SMS GmbH
InventorsMarkus Waiblinger, Michael Budach, Thomas Scherübl, Dirk Beyer
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Abstract
The invention relates to a method for determining a performance of a photolithographic mask at an exposure wavelength with the steps of scanning at least one electron beam across at least one portion of the photolithographic mask, measuring signals generated by the at least one electron beam interacting with the at least one portion of the photolithographic mask, and determining the performance of the at least one portion of the photolithographic mask at the exposure wavelength based on the measured signals.
Claims21
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.
An apparatus for predicting a performance of a photolithographic mask at a predetermined exposure wavelength, comprising:
- a. at least one electron source for generating at least one electron beam, wherein the at least one electron source is operable to generate electron beams with multiple energies, and 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. at least one adjusting means for repeatedly scanning the at least one electron beam with multiple beam energies across the at least one portion of the photolithographic mask;
- c. at least one detector for 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 positional information on the defect;
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- d. at least one computing means for determining whether the defect is a defect of an absorber layer of the photolithographic mask or a defect of a multilayer 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 determining whether a repair of the defect is required based on a discrepancy between the determined performance and a predetermined performance.
Dependencies are inferred from the claim text.