Patent ID: 6562528
Filing Date: 2003-05-13
Classification: G03F

Abstract:
In a photolithography system having an exposure apparatus that exposes a pattern onto a photosensitive surface in a substrate plane of a substrate that nominally lies in an image plane of the exposure apparatus defined by two orthogonal axes, a method for determining image plane tilt and substrate plane tilt about at least one of the orthogonal axes, comprising:subjecting a first test area to a series of exposures across the first test area; subjecting a second test area, which is displaced from the first test area in a direction of a first orthogonal axis, to a substantially same series of exposures across the second test area; developing images from the exposures in the first and second test areas, wherein the image in each test area includes an image of at least a line of best focus where the image plane and the substrate plane coincide; and identifying a presence of substrate plane tilt and image plant tilt about the second axis by comparing the images in the first and second test areas.