Patent ID: 11914289
Assignee: CARL ZEISS SMS LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 17:
18. A method for determining an effect of one or more pixels to be introduced into a substrate of a photolithographic mask for at least partly correcting one or more errors of the photolithographic mask, the photolithographic mask having one or more pattern elements, wherein one or more calibration pixels serve to determine a fitted curve that can be used for controlling a pixel writing that at least partly corrects the one or more errors of the photolithographic mask, the method comprising:
determining a change in birefringence of the substrate of the photolithographic mask as a function of at least one laser beam parameter of a laser system used for introducing the one or more calibration pixels into the substrate of the photolithographic mask, wherein the laser system has a wavelength that is larger than an actinic wavelength of the photolithographic mask, the actinic wavelength being the wavelength the photolithographic mask is designed for illuminating a photoresist on a wafer;
determining an optical transmission variation of the substrate of the photolithographic mask as a function of the at least one laser beam parameter; and
determining the fitted curve representing a relationship between the change in birefringence of the substrate with the optical transmission variation of the substrate caused by the one or more calibration pixels introduced into the substrate, wherein the at least one laser beam parameter is a parameter.