Abstract: A system and method for uniformity correction is provided. The system includes a plurality of winged correction elements inserted into the illumination field in a defined configuration. Adjacent winged correction elements are overlapped to minimize induced uniformity ripple. Each winged correction element has a first protrusion on a longitudinal edge of the correction element and a second protrusion on the opposite longitudinal edge. The slope of a sloped edge of the first protrusion and the slope of a sloped edge of the second protrusion are tied to the slope of a gradient in the non-uniformity profile of the illumination field. In addition, the angles defined by the flat tip of the correction element and the sloped edge of the first and second protrusions are tied to the angle of a gradient of the illumination field.

Abstract: A removable cover for protecting a reticle used in a lithography system is described. The removable cover includes a frame and a membrane supported by the frame. The membrane is transparent to an inspection wavelength such that the reticle can be inspected with the removable cover in place. This removable cover protects the reticle when the removable cover is in place and is removable for lithographic exposure. The removable cover can further include at least one reticle fastener that applies force to the reticle thereby preventing movement of the removable cover relative to the reticle when the removable cover is in place. A plurality of fasteners are used to position and secure the removable cover and reticle. A method of performing lithography and a lithographic system are also described.