Abstract: The present invention refers to a method for determining an effect of one or more of pixels to be introduced into a substrate of a photolithographic mask, the photolithographic mask having one or more pattern elements, wherein the one or more pixels serve to at least partly correct one or more errors of the photolithographic mask, the method comprising: determining the effect of the one or more introduced pixels by determining a change in birefringence of the substrate of the photolithographic mask having the one or more pattern elements.

Abstract: An optical system includes a scanning unit, a first lens-element group including at least a first lens element, and a focusing unit which is designed to focus beams onto a focus, wherein the focusing unit includes a second lens-element group including at least a second lens element and an imaging lens. The imaging lens further includes a pupil plane and a wavefront manipulator. The wavefront manipulator is arranged in the pupil plane of the imaging lens or in a plane that is conjugate to the pupil plane, or the scanning unit of the optical system is arranged in a plane that is conjugate to the pupil plane and the wavefront manipulator is arranged upstream of the scanning unit in the light direction. The focus of the second lens-element group lies in the pupil plane of the imaging lens in all focal positions of the focusing unit.

Abstract: The present invention refers to a method for determining an effect of one or more of pixels to be introduced into a substrate of a photolithographic mask, the photolithographic mask having one or more pattern elements, wherein the one or more pixels serve to at least partly correct one or more errors of the photolithographic mask, the method comprising: determining the effect of the one or more introduced pixels by determining a change in birefringence of the substrate of the photolithographic mask having the one or more pattern elements.

Abstract: The inventions concerns an optical system comprising a scanning unit, a first lens-element group comprising at least a first lens element, a focusing unit which is designed to focus beams onto a focus, wherein the focusing unit comprises a second lens-element group comprising at least a second lens element and an imaging lens. The imaging lens further comprises a pupil plane and a wavefront manipulator. The wavefront manipulator of the optical system is arranged in the pupil plane of the imaging lens or in a plane that is conjugate to the pupil plane of the imaging lens, or the scanning unit of the optical system is arranged in a plane that is conjugate to the pupil plane of the imaging lens and the wavefront manipulator is arranged upstream of the scanning unit in the light direction. The focus of the second lens-element group lies in the pupil plane of the imaging lens in all focal positions of the focusing unit.

Abstract: The invention relates to a method for locally deforming an optical element for photolithography in accordance with a predefined deformation form comprising: (a) generating at least one laser pulse having at least one laser beam parameter; and (b) directing the at least one laser pulse onto the optical element, wherein the at least one laser beam parameter of the laser pulse is selected to yield the predefined deformation form.

Abstract: The invention relates to a method for locally deforming an optical element for photolithography in accordance with a predefined deformation form comprising: (a) generating at least one laser pulse having at least one laser beam parameter; and (b) directing the at least one laser pulse onto the optical element, wherein the at least one laser beam parameter of the laser pulse is selected to yield the predefined deformation form.